Graded inhibition of oncogenic Ras-signaling by multivalent Ras-binding domains

PubMed Central

2014-01-01

Background Ras is a membrane-associated small G-protein that funnels growth and differentiation signals into downstream signal transduction pathways by cycling between an inactive, GDP-bound and an active, GTP-bound state. Aberrant Ras activity as a result of oncogenic mutations causes de novo cell transformation and promotes tumor growth and progression. Results Here, we describe a novel strategy to block deregulated Ras activity by means of oligomerized cognate protein modules derived from the Ras-binding domain of c-Raf (RBD), which we named MSOR for multivalent scavengers of oncogenic Ras. The introduction of well-characterized mutations into RBD was used to adjust the affinity and hence the blocking potency of MSOR towards activated Ras. MSOR inhibited several oncogenic Ras-stimulated processes including downstream activation of Erk1/2, induction of matrix-degrading enzymes, cell motility and invasiveness in a graded fashion depending on the oligomerization grade and the nature of the individual RBD-modules. The amenability to accurate experimental regulation was further improved by engineering an inducible MSOR-expression system to render the reversal of oncogenic Ras effects controllable. Conclusion MSOR represent a new tool for the experimental and possibly therapeutic selective blockade of oncogenic Ras signals. PMID:24383791

Epigenetic Alterations in Human Papillomavirus-Associated Cancers

PubMed Central

Song, Christine; McLaughlin-Drubin, Margaret E.

2017-01-01

Approximately 15–20% of human cancers are caused by viruses, including human papillomaviruses (HPVs). Viruses are obligatory intracellular parasites and encode proteins that reprogram the regulatory networks governing host cellular signaling pathways that control recognition by the immune system, proliferation, differentiation, genomic integrity, and cell death. Given that key proteins in these regulatory networks are also subject to mutation in non-virally associated diseases and cancers, the study of oncogenic viruses has also been instrumental to the discovery and analysis of many fundamental cellular processes, including messenger RNA (mRNA) splicing, transcriptional enhancers, oncogenes and tumor suppressors, signal transduction, immune regulation, and cell cycle control. More recently, tumor viruses, in particular HPV, have proven themselves invaluable in the study of the cancer epigenome. Epigenetic silencing or de-silencing of genes can have cellular consequences that are akin to genetic mutations, i.e., the loss and gain of expression of genes that are not usually expressed in a certain cell type and/or genes that have tumor suppressive or oncogenic activities, respectively. Unlike genetic mutations, the reversible nature of epigenetic modifications affords an opportunity of epigenetic therapy for cancer. This review summarizes the current knowledge on epigenetic regulation in HPV-infected cells with a focus on those elements with relevance to carcinogenesis. PMID:28862667

The epithelial polarity regulator LGALS9/galectin-9 induces fatal frustrated autophagy in KRAS mutant colon carcinoma that depends on elevated basal autophagic flux

PubMed Central

Wiersma, Valerie R; de Bruyn, Marco; Wei, Yunwei; van Ginkel, Robert J; Hirashima, Mitsuomi; Niki, Toshiro; Nishi, Nozomu; Zhou, Jin; Pouwels, Simon D; Samplonius, Douwe F; Nijman, Hans W; Eggleton, Paul; Helfrich, Wijnand; Bremer, Edwin

2015-01-01

Oncogenic mutation of KRAS (Kirsten rat sarcoma viral oncogene homolog) in colorectal cancer (CRC) confers resistance to both chemotherapy and EGFR (epidermal growth factor receptor)-targeted therapy. We uncovered that KRAS mutant (KRASmut) CRC is uniquely sensitive to treatment with recombinant LGALS9/Galectin-9 (rLGALS9), a recently established regulator of epithelial polarity. Upon treatment of CRC cells, rLGALS9 rapidly internalizes via early- and late-endosomes and accumulates in the lysosomal compartment. Treatment with rLGALS9 is accompanied by induction of frustrated autophagy in KRASmut CRC, but not in CRC with BRAF (B-Raf proto-oncogene, serine/threonine kinase) mutations (BRAFmut). In KRASmut CRC, rLGALS9 acts as a lysosomal inhibitor that inhibits autophagosome-lysosome fusion, leading to autophagosome accumulation, excessive lysosomal swelling and cell death. This antitumor activity of rLGALS9 directly correlates with elevated basal autophagic flux in KRASmut cancer cells. Thus, rLGALS9 has potent antitumor activity toward refractory KRASmut CRC cells that may be exploitable for therapeutic use. PMID:26086204

The cornerstone K-RAS mutation in pancreatic adenocarcinoma: From cell signaling network, target genes, biological processes to therapeutic targeting.

PubMed

Jonckheere, Nicolas; Vasseur, Romain; Van Seuningen, Isabelle

2017-03-01

RAS belongs to the super family of small G proteins and plays crucial roles in signal transduction from membrane receptors in the cell. Mutations of K-RAS oncogene lead to an accumulation of GTP-bound proteins that maintains an active conformation. In the pancreatic ductal adenocarcinoma (PDAC), one of the most deadly cancers in occidental countries, mutations of the K-RAS oncogene are nearly systematic (>90%). Moreover, K-RAS mutation is the earliest genetic alteration occurring during pancreatic carcinogenetic sequence. In this review, we discuss the central role of K-RAS mutations and their tremendous diversity of biological properties by the interconnected regulation of signaling pathways (MAPKs, NF-κB, PI3K, Ral…). In pancreatic ductal adenocarcinoma, transcriptome analysis and preclinical animal models showed that K-RAS mutation alters biological behavior of PDAC cells (promoting proliferation, migration and invasion, evading growth suppressors, regulating mucin pattern, and miRNA expression). K-RAS also impacts tumor microenvironment and PDAC metabolism reprogramming. Finally we discuss therapeutic targeting strategies of K-RAS that have been developed without significant clinical success so far. As K-RAS is considered as the undruggable target, targeting its multiple effectors and target genes should be considered as potential alternatives. Copyright © 2017 Elsevier B.V. All rights reserved.

TAD disruption as oncogenic driver

PubMed Central

Valton, Anne-Laure; Dekker, Job

2016-01-01

Topologically Associating Domains (TADs) are conserved during evolution and play roles in guiding and constraining long-range regulation of gene expression. Disruption of TAD boundaries results in aberrant gene expression by exposing genes to inappropriate regulatory elements. Recent studies have shown that TAD disruption is often found in cancer cells and contributes to oncogenesis through two mechanisms. One mechanism locally disrupts domains by deleting or mutating a TAD boundary leading to fusion of the two adjacent TADs. The other mechanism involves genomic rearrangements that break up TADs and creates new ones without directly affecting TAD boundaries. Understanding the mechanisms by which TADs form and control long-range chromatin interactions will therefore not only provide insights into the mechanism of gene regulation in general, but will also reveal how genomic rearrangements and mutations in cancer genomes can lead to misregulation of oncogenes and tumor suppressors. PMID:27111891

Disruption of PH–kinase domain interactions leads to oncogenic activation of AKT in human cancers

PubMed Central

Parikh, Chaitali; Janakiraman, Vasantharajan; Wu, Wen-I; Foo, Catherine K.; Kljavin, Noelyn M.; Chaudhuri, Subhra; Stawiski, Eric; Lee, Brian; Lin, Jie; Li, Hong; Lorenzo, Maria N.; Yuan, Wenlin; Guillory, Joseph; Jackson, Marlena; Rondon, Jesus; Franke, Yvonne; Bowman, Krista K.; Sagolla, Meredith; Stinson, Jeremy; Wu, Thomas D.; Wu, Jiansheng; Stokoe, David; Stern, Howard M.; Brandhuber, Barbara J.; Lin, Kui; Skelton, Nicholas J.; Seshagiri, Somasekar

2012-01-01

The protein kinase v-akt murine thymoma viral oncogene homolog (AKT), a key regulator of cell survival and proliferation, is frequently hyperactivated in human cancers. Intramolecular pleckstrin homology (PH) domain–kinase domain (KD) interactions are important in maintaining AKT in an inactive state. AKT activation proceeds after a conformational change that dislodges the PH from the KD. To understand these autoinhibitory interactions, we generated mutations at the PH–KD interface and found that most of them lead to constitutive activation of AKT. Such mutations are likely another mechanism by which activation may occur in human cancers and other diseases. In support of this likelihood, we found somatic mutations in AKT1 at the PH–KD interface that have not been previously described in human cancers. Furthermore, we show that the AKT1 somatic mutants are constitutively active, leading to oncogenic signaling. Additionally, our studies show that the AKT1 mutants are not effectively inhibited by allosteric AKT inhibitors, consistent with the requirement for an intact PH–KD interface for allosteric inhibition. These results have important implications for therapeutic intervention in patients with AKT mutations at the PH–KD interface. PMID:23134728

Unique presentation of cutis laxa with Leigh-like syndrome due to ECHS1 deficiency.

PubMed

Balasubramaniam, S; Riley, L G; Bratkovic, D; Ketteridge, D; Manton, N; Cowley, M J; Gayevskiy, V; Roscioli, T; Mohamed, M; Gardeitchik, T; Morava, E; Christodoulou, J

2017-09-01

Clinical finding of cutis laxa, characterized by wrinkled, redundant, sagging, nonelastic skin, is of growing significance due to its occurrence in several different inborn errors of metabolism (IEM). Metabolic cutis laxa results from Menkes syndrome, caused by a defect in the ATPase copper transporting alpha (ATP7A) gene; congenital disorders of glycosylation due to mutations in subunit 7 of the component of oligomeric Golgi (COG7)-congenital disorders of glycosylation (CDG) complex; combined disorder of N- and O-linked glycosylation, due to mutations in ATPase H+ transporting V0 subunit a2 (ATP6VOA2) gene; pyrroline-5-carboxylate reductase 1 deficiency; pyrroline-5-carboxylate synthase deficiency; macrocephaly, alopecia, cutis laxa, and scoliosis (MACS) syndrome, due to Ras and Rab interactor 2 (RIN2) mutations; transaldolase deficiency caused by mutations in the transaldolase 1 (TALDO1) gene; Gerodermia osteodysplastica due to mutations in the golgin, RAB6-interacting (GORAB or SCYL1BP1) gene; and mitogen-activated pathway (MAP) kinase defects, caused by mutations in several genes [protein tyrosine phosphatase, non-receptor-type 11 (PTPN11), RAF, NF, HRas proto-oncogene, GTPase (HRAS), B-Raf proto-oncogene, serine/threonine kinase (BRAF), MEK1/2, KRAS proto-oncogene, GTPase (KRAS), SOS Ras/Rho guanine nucleotide exchange factor 2 (SOS2), leucine rich repeat scaffold protein (SHOC2), NRAS proto-oncogene, GTPase (NRAS), and Raf-1 proto-oncogene, serine/threonine kinase (RAF1)], which regulate the Ras-MAPK cascade. Here, we further expand the list of inborn errors of metabolism associated with cutis laxa by describing the clinical presentation of a 17-month-old girl with Leigh-like syndrome due to enoyl coenzyme A hydratase, short chain, 1, mitochondria (ECHS1) deficiency, a mitochondrial matrix enzyme that catalyzes the second step of the beta-oxidation spiral of fatty acids and plays an important role in amino acid catabolism, particularly valine.

Heat shock protein 70 regulates Tcl1 expression in leukemia and lymphomas

PubMed Central

Gaudio, Eugenio; Paduano, Francesco; Ngankeu, Apollinaire; Lovat, Francesca; Fabbri, Muller; Sun, Hui-Lung; Gasparini, Pierluigi; Efanov, Alexey; Peng, Yong; Zanesi, Nicola; Shuaib, Mohammed A.; Rassenti, Laura Z.; Kipps, Thomas J.; Li, Chenglong; Aqeilan, Rami I.; Lesinski, Gregory B.; Trapasso, Francesco

2013-01-01

T-cell leukemia/lymphoma 1 (TCL1) is an oncogene overexpressed in T-cell prolymphocytic leukemia and in B-cell malignancies including B-cell chronic lymphocytic leukemia and lymphomas. To date, only a limited number of Tcl1-interacting proteins that regulate its oncogenic function have been identified. Prior studies used a proteomic approach to identify a novel interaction between Tcl1 with Ataxia Telangiectasia Mutated. The association of Tcl1 and Ataxia Telangiectasia Mutated leads to activation of the NF-κB pathway. Here, we demonstrate that Tcl1 also interacts with heat shock protein (Hsp) 70. The Tcl1-Hsp70 complex was validated by coimmunoprecipitation experiments. In addition, we report that Hsp70, a protein that plays a critical role in the folding and maturation of several oncogenic proteins, associates with Tcl1 protein and stabilizes its expression. The inhibition of the ATPase activity of Hsp70 results in ubiquitination and proteasome-dependent degradation of Tcl1. The inhibition of Hsp70 significantly reduced the growth of lymphoma xenografts in vivo and down-regulated the expression of Tcl1 protein. Our findings reveal a functional interaction between Tcl1 and Hsp70 and identify Tcl1 as a novel Hsp70 client protein. These findings suggest that inhibition of Hsp70 may represent an alternative effective therapy for chronic lymphocytic leukemia and lymphomas via its ability to inhibit the oncogenic functions of Tcl1. PMID:23160471

Regulation of leukemia-initiating cell activity by the ubiquitin ligase FBXW7

PubMed Central

King, Bryan; Trimarchi, Thomas; Reavie, Linsey; Xu, Luyao; Mullenders, Jasper; Ntziachristos, Panagiotis; Aranda-Orgilles, Beatriz; Perez-Garcia, Arianne; Shi, Junwei; Vakoc, Christopher; Sandy, Peter; Shen, Steven S.; Ferrando, Adolfo; Aifantis, Iannis

2013-01-01

SUMMARY Sequencing efforts led to the identification of somatic mutations that could affect self-renewal and differentiation of cancer-initiating cells. One such recurrent mutation targets the binding pocket of the ubiquitin ligase FBXW7. Missense FBXW7 mutations are prevalent in various tumors, including T-cell acute lymphoblastic leukemia (T-ALL). To study the effects of such lesions, we generated animals carrying regulatable Fbxw7 mutant alleles. We show here that these mutations specifically bolster cancer-initiating cell activity in collaboration with Notch1 oncogenes, but spare normal hematopoietic stem cell function. We were also able to show that FBXW7 mutations specifically affect the ubiquitylation and half-life of c-Myc protein, a key T-ALL oncogene. Using animals carrying c-Myc fusion alleles, we connected Fbxw7 function to c-Myc abundance and correlated c-Myc expression to leukemia-initiating activity. Finally, we demonstrated that small molecule-mediated suppression of MYC activity leads to T-ALL remission, suggesting a novel effective therapeutic strategy. PMID:23791182

CYCLOPENTA-FUSED POLYCYCLIC AROMATIC HYDROCARBONS IN STRAIN A/J MOUSE LUNG: DNA ADDUCTS, ONCOGENE MUTATIONS, & TUMORIGENESIS

EPA Science Inventory

Cyclopenta-fused Polycyclic Aromatic Hydrocarbons in Strain AJJ Mouse Lung: DNA Adducts, Oncogene Mutations, and Tumorigenesis.

We have examined the relationships between DNA adducts, Ki-ras oncogene mutations, DNA adducts, and adenoma induction in the lungs of strain A/J...

TAD disruption as oncogenic driver.

PubMed

Valton, Anne-Laure; Dekker, Job

2016-02-01

Topologically Associating Domains (TADs) are conserved during evolution and play roles in guiding and constraining long-range regulation of gene expression. Disruption of TAD boundaries results in aberrant gene expression by exposing genes to inappropriate regulatory elements. Recent studies have shown that TAD disruption is often found in cancer cells and contributes to oncogenesis through two mechanisms. One mechanism locally disrupts domains by deleting or mutating a TAD boundary leading to fusion of the two adjacent TADs. The other mechanism involves genomic rearrangements that break up TADs and creates new ones without directly affecting TAD boundaries. Understanding the mechanisms by which TADs form and control long-range chromatin interactions will therefore not only provide insights into the mechanism of gene regulation in general, but will also reveal how genomic rearrangements and mutations in cancer genomes can lead to misregulation of oncogenes and tumor suppressors. Copyright © 2016 Elsevier Ltd. All rights reserved.

3D view to tumor suppression: Lkb1, polarity and the arrest of oncogenic c-Myc.

PubMed

Partanen, Johanna I; Nieminen, Anni I; Klefstrom, Juha

2009-03-01

Machiavelli wrote, in his famous political treatise Il Principe, about disrupting organization by planting seeds of dissension or by eliminating necessary support elements. Tumor cells do exactly that by disrupting the organized architecture of epithelial cell layers during progression from contained benign tumor to full-blown invasive cancer. However, it is still unclear whether tumor cells primarily break free by activating oncogenes powerful enough to cause chaos or by eliminating tumor suppressor genes guarding the order of the epithelial organization. Studies in Drosophila have exposed genes that encode key regulators of the epithelial apicobasal polarity and which, upon inactivation, cause disorganization of the epithelial layers and promote unscheduled cell proliferation. These polarity regulator/tumor suppressor proteins, which include products of neoplastic tumor suppressor genes (nTSGs), are carefully positioned in polarized epithelial cells to maintain the order of epithelial structures and to impose a restraint on cell proliferation. In this review, we have explored the presence and prevalence of somatic mutations in the human counterparts of Drosophila polarity regulator/tumor suppressor genes across the human cancers. The screen points out LKB1, which is a causal genetic lesion in Peutz-Jeghers cancer syndrome, a gene mutated in certain sporadic cancers and a human homologue of the fly polarity gene par-4. We review the evidence linking Lkb1 protein to polarity regulation in the scope of our recent results suggesting a coupled role for Lkb1 as an architect of organized acinar structures and a suppressor of oncogenic c-Myc. We finally present models to explain how Lkb1-dependent formation of epithelial architecture is coupled to suppression of normal and oncogene-induced proliferation.

The Oncogenic Role of RhoGAPs in Basal-Like Breast Cancer

DTIC Science & Technology

2016-04-01

somatic mutations of RhoA in peripheral T cell lymphomas (PTCLs) (16-18) and in diffuse-type gastric carcinomas (19-21). Surprisingly, unlike Rac1...Diffuse-type gastric cancers exhibited mutations in the effector binding domain of RhoA, most commonly Y42C (19-21), which prevents binding to the...Impiombato A, Perez-Garcia A, et al. Recurrent mutations in epigenetic regulators, RHOA and FYN kinase in peripheral T cell lymphomas . Nat Genet 2014;46

A Novel Ras Effector Pathway Found to Play Significant Role in Tumor Suppression | Poster

Cancer.gov

By Nancy Parrish, Staff Writer; photo by Richard Frederickson, Staff Photographer Normal cells have mechanisms to prevent the development of cancer. Among these is a type of tumor suppressor mechanism known as oncogene-induced senescence, or OIS, which halts the uncontrolled growth of cells caused by mutations in oncogenes. The oncogene Ras plays a crucial role in inducing OIS through a specific cascade of proteins, as reported in a recent article in Molecular and Cellular Biology by Jacqueline Salotti, Ph.D., and colleagues in the Eukaryotic Transcriptional Regulation Section of the Mouse Cancer Genetics Program, Center for Cancer Research (CCR).

Casein kinase 1α–dependent feedback loop controls autophagy in RAS-driven cancers

PubMed Central

Cheong, Jit Kong; Zhang, Fuquan; Chua, Pei Jou; Bay, Boon Huat; Thorburn, Andrew; Virshup, David M.

2015-01-01

Activating mutations in the RAS oncogene are common in cancer but are difficult to therapeutically target. RAS activation promotes autophagy, a highly regulated catabolic process that metabolically buffers cells in response to diverse stresses. Here we report that casein kinase 1α (CK1α), a ubiquitously expressed serine/threonine kinase, is a key negative regulator of oncogenic RAS–induced autophagy. Depletion or pharmacologic inhibition of CK1α enhanced autophagic flux in oncogenic RAS–driven human fibroblasts and multiple cancer cell lines. FOXO3A, a master longevity mediator that transcriptionally regulates diverse autophagy genes, was a critical target of CK1α, as depletion of CK1α reduced levels of phosphorylated FOXO3A and increased expression of FOXO3A-responsive genes. Oncogenic RAS increased CK1α protein abundance via activation of the PI3K/AKT/mTOR pathway. In turn, elevated levels of CK1α increased phosphorylation of nuclear FOXO3A, thereby inhibiting transactivation of genes critical for RAS-induced autophagy. In both RAS-driven cancer cells and murine xenograft models, pharmacologic CK1α inactivation synergized with lysosomotropic agents to inhibit growth and promote tumor cell death. Together, our results identify a kinase feedback loop that influences RAS-dependent autophagy and suggest that targeting CK1α-regulated autophagy offers a potential therapeutic opportunity to treat oncogenic RAS–driven cancers. PMID:25798617

Chromatin modifiers and the promise of epigenetic therapy in acute leukemia

PubMed Central

Greenblatt, Sarah M.; Nimer, Stephen D.

2017-01-01

Hematopoiesis is a tightly regulated process involving the control of gene expression that directs the transition from hematopoietic stem and progenitor cells to terminally differentiated blood cells. In leukemia, the processes directing self-renewal, differentiation, and progenitor cell expansion are disrupted, leading to the accumulation of immature, non-functioning malignant cells. Insights into these processes have come in stages, based upon technological advances in genetic analyses, bioinformatics, and biological sciences. The first cytogenetic studies of leukemic cells identified chromosomal translocations that generate oncogenic fusion proteins, and most commonly affect regulators of transcription. This was followed by the discovery of recurrent somatic mutations in genes encoding regulators of the signal transduction pathways that control cell proliferation and survival. Recently, studies of global changes in methylation and gene expression have led to the understanding that the output of transcriptional regulators and the proliferative signaling pathways, are ultimately influenced by chromatin structure. Candidate gene, whole genome, and whole exome sequencing studies have identified recurrent somatic mutations in genes encoding epigenetic modifiers in both acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). In contrast to the two hit model of leukemogenesis, emerging evidence suggests that these epigenetic modifiers represent a class of mutations that are critical to the development of leukemia and affect the regulation of various other oncogenic pathways. In this review, we discuss the range of recurrent, somatic mutations in epigenetic modifiers found in leukemia and how these modifiers relate to the classical leukemogenic pathways that lead to impaired cell differentiation and aberrant self-renewal and proliferation. PMID:24609046

K-RasG12D–induced T-cell lymphoblastic lymphoma/leukemias harbor Notch1 mutations and are sensitive to γ-secretase inhibitors

PubMed Central

Cornejo, Melanie G.; Scholl, Claudia; Liu, Jianing; Leeman, Dena S.; Haydu, J. Erika; Fröhling, Stefan; Lee, Benjamin H.; Gilliland, D. Gary

2008-01-01

To study the impact of oncogenic K-Ras on T-cell leukemia/lymphoma development and progression, we made use of a conditional K-RasG12D murine knockin model, in which oncogenic K-Ras is expressed from its endogenous promoter. Transplantation of whole bone marrow cells that express oncogenic K-Ras into wild-type recipient mice resulted in a highly penetrant, aggressive T-cell leukemia/lymphoma. The lymphoblasts were composed of a CD4/CD8 double-positive population that aberrantly expressed CD44. Thymi of primary donor mice showed reduced cellularity, and immunophenotypic analysis demonstrated a block in differentiation at the double-negative 1 stage. With progression of disease, approximately 50% of mice acquired Notch1 mutations within the PEST domain. Of note, primary lymphoblasts were hypersensitive to γ-secretase inhibitor treatment, which is known to impair Notch signaling. This inhibition was Notch-specific as assessed by down-regulation of Notch1 target genes and intracellular cleaved Notch. We also observed that the oncogenic K-Ras-induced T-cell disease was responsive to rapamycin and inhibitors of the RAS/MAPK pathway. These data indicate that patients with T-cell leukemia with K-Ras mutations may benefit from therapies that target the NOTCH pathway alone or in combination with inhibition of the PI3K/AKT/MTOR and RAS/MAPK pathways. PMID:18663146

Concurrent Oncogene Mutation Profile in Chinese Patients With Stage Ib Lung Adenocarcinoma

PubMed Central

Wen, Ying-Sheng; Cai, Ling; Zhang, Xue-wen; Zhu, Jian-fei; Zhang, Zi-chen; Shao, Jian-yong; Zhang, Lan-Jun

2014-01-01

Abstract Molecular characteristics in lung cancer are associated with carcinogenesis, response to targeted therapies, and prognosis. With concurrent oncogene mutations being reported more often, the adjustment of treatment based on the driver gene mutations would improve therapy. We proposed to investigate the distribution of concurrent oncogene mutations in stage Ib lung adenocarcinoma in a Chinese population and find out the correlation between survival outcome and the most frequently mutated genes in EGFR and KRAS in Chinese population. Simultaneously, we tried to validate the Sequenom method by real time fluoresce qualification reverse transcription polymerase chain reaction (RT-PCR) in oncogene detection. One hundred fifty-six patients who underwent complete surgical resection in our hospital between 1999 and 2007 were retrospectively investigated. Using time-of-flight mass spectrometry, 238 mutation hotspots in 19 oncogenes were examined. Genetic mutations occurred in 86 of 156 patients (55.13%). EGFR was most frequently gene contained driver mutations, with a rate of 44.23%, followed by KRAS (8.33%), PIK3CA (3.84%), KIT (3.20%), BRAF (2.56%), AKT (1.28%), MET (0.64%), NRAS (0.64%), HRAS (0.64%), and ERBB2 (0.64%). No mutations were found in the RET, PDGFRA, FGFR1, FGFR3, FLT3, ABL, CDK, or JAK2 oncogenes. Thirteen patients (8.3%) were detected in multiple gene mutations. Six patients had PIK3CA mutations in addition to mutations in EGFR and KRAS. EGFR mutations can coexist with mutations in NRAS, KIT, ERBB2, and BRAF. Only one case was found to have a KRAS mutation coexisting with the EGFR T790M mutation. Otherwise, mutations in EGFR and KRAS seem to be mutually exclusive. There is no survival benefit in favor of EGFR/KRAS mutation. Several concomitant driver gene mutations were observed in our study. None of EFGR/KRAS mutation was demonstrated as a prognostic factor. Polygenic mutation testing by time-of-flight mass spectrometry was validated by RT-PCR, which can be an alternative option to test for multiple mutations and can be widely applied to clinical practice and help to guide treatment. PMID:25546673

Oncogenic Ras induces inflammatory cytokine production by up-regulating the squamous cell carcinoma antigens SerpinB3/B4

PubMed Central

Pan, Ji-An; Sun, Yu; Shi, Chanjuan; Li, Jinyu; Powers, R. Scott; Crawford, Howard C.; Zong, Wei-Xing

2014-01-01

Mounting evidence indicates that oncogenic Ras can modulate cell autonomous inflammatory cytokine production, although the underlying mechanism remains unclear. Here we show that squamous cell carcinoma antigens 1 and 2 (SCCA1/2), members of the Serpin family of serine/cysteine protease inhibitors, are transcriptionally up-regulated by oncogenic Ras via MAPK and the ETS family transcription factor PEA3. Increased SCCA expression leads to inhibition of protein turnover, unfolded protein response, activation of NF-κB, and is essential for Ras-mediated cytokine production and tumor growth. Analysis of human colorectal and pancreatic tumor samples reveals a positive correlation between Ras mutation, enhanced SCCA expression, and IL-6 expression. These results indicate that SCCA is a Ras-responsive factor that has a role in Ras-associated cytokine production and tumorigenesis. PMID:24759783

The Energy Landscape Analysis of Cancer Mutations in Protein Kinases

PubMed Central

Dixit, Anshuman; Verkhivker, Gennady M.

2011-01-01

The growing interest in quantifying the molecular basis of protein kinase activation and allosteric regulation by cancer mutations has fueled computational studies of allosteric signaling in protein kinases. In the present study, we combined computer simulations and the energy landscape analysis of protein kinases to characterize the interplay between oncogenic mutations and locally frustrated sites as important catalysts of allostetric kinase activation. While structurally rigid kinase core constitutes a minimally frustrated hub of the catalytic domain, locally frustrated residue clusters, whose interaction networks are not energetically optimized, are prone to dynamic modulation and could enable allosteric conformational transitions. The results of this study have shown that the energy landscape effect of oncogenic mutations may be allosteric eliciting global changes in the spatial distribution of highly frustrated residues. We have found that mutation-induced allosteric signaling may involve a dynamic coupling between structurally rigid (minimally frustrated) and plastic (locally frustrated) clusters of residues. The presented study has demonstrated that activation cancer mutations may affect the thermodynamic equilibrium between kinase states by allosterically altering the distribution of locally frustrated sites and increasing the local frustration in the inactive form, while eliminating locally frustrated sites and restoring structural rigidity of the active form. The energy landsape analysis of protein kinases and the proposed role of locally frustrated sites in activation mechanisms may have useful implications for bioinformatics-based screening and detection of functional sites critical for allosteric regulation in complex biomolecular systems. PMID:21998754

Child with RET proto-oncogene codon 634 mutation.

PubMed

İnce, Dilek; Demirağ, Bengü; Ataseven, Eda; Oymak, Yeşim; Tuhan, Hale; Karakuş, Osman Zeki; Hazan, Filiz; Abacı, Ayhan; Özer, Erdener; Mutafoglu, Kamer; Olgun, Nur

2017-01-01

İnce D, Demirağ B, Ataseven E, Oymak Y, Tuhan H, Karakuş OZ, Hazan F, Abacı A, Özer E, Mutafoglu K, Olgun N. Child with RET proto-oncogene codon 634 mutation. Turk J Pediatr 2017; 59: 590-593. Herein we reported a 7-year-old child with RET proto-oncogene c634 mutation. Her mother had been diagnosed with medullary thyroid carcinoma (MTC), and treated six years ago. Heterozygous mutation of the RET proto-oncogene at c634 had been detected in her mother. Genetic analysis showed the presence of the same mutation in our patient. Thyroid functions were normal. Serum calcitonin level was found mildly elevated. Parathormone (PTH) and carcinoembrionic antigen (CEA) levels were normal. Prophylactic thyroidectomy and sampling of cervical lymph nodes were performed. Histopathologic examination revealed hyperplasia in thyroid C cells, and reactive lymphadenopathy. The risk of MTC has been reported 100% through the life of patients with RET proto-oncogene mutation. It has been reported that particularly patients with c634 mutation have more risk of occurence of metastatic and progressive/recurrent MTC. Prophylactic `thyroidectomy, cervical lymph node dissection` before 5-years-of-age should be considered for these patients.

Remarkable difference of somatic mutation patterns between oncogenes and tumor suppressor genes.

PubMed

Liu, Haoxuan; Xing, Yuhang; Yang, Sihai; Tian, Dacheng

2011-12-01

Cancers arise owing to mutations that confer selective growth advantages on the cells in a subset of tumor suppressor and/or oncogenes. To understand oncogenesis and diagnose cancers, it is crucial to discriminate these two groups of genes by using the difference in their mutation patterns. Here, we investigated>120,000 mutation samples in 66 well-known tumor suppressor genes and oncogenes of the COSMIC database, and found a set of significant differences in mutation patterns (e.g., non-3n-indel, non-sense SNP and mutation hotspot) between them. By screening the best measurement, we developed indices to readily distinguish one from another and predict clearly the unknown oncogenesis genes as tumor suppressors (e.g., ASXL1, HNF1A and KDM6A) or oncogenes (e.g., FOXL2, MYD88 and TSHR). Based on our results, a third gene group can be classified, which has a mutational pattern between tumor suppressors and oncogenes. The concept of the third gene group could help to understand gene function in different cancers or individual patients and to know the exact function of genes in oncogenesis. In conclusion, our study provides further insights into cancer-related genes and identifies several potential therapeutic targets.

Genomic Profiling on an Unselected Solid Tumor Population Reveals a Highly Mutated Wnt/β-Catenin Pathway Associated with Oncogenic EGFR Mutations.

PubMed

Jiang, Jingrui; Protopopov, Alexei; Sun, Ruobai; Lyle, Stephen; Russell, Meaghan

2018-04-09

Oncogenic epidermal growth factor receptors (EGFRs) can recruit key effectors in diverse cellular processes to propagate oncogenic signals. Targeted and combinational therapeutic strategies have been successfully applied for treating EGFR-driven cancers. However, a main challenge in EGFR therapies is drug resistance due to mutations, oncogenic shift, alternative signaling, and other potential mechanisms. To further understand the genetic alterations associated with oncogenic EGFRs and to provide further insight into optimal and personalized therapeutic strategies, we applied a proprietary comprehensive next-generation sequencing (NGS)-based assay of 435 genes to systematically study the genomic profiles of 1565 unselected solid cancer patient samples. We found that activating EGFR mutations were predominantly detected in lung cancer, particularly in non-small cell lung cancer (NSCLC). The mutational landscape of EGFR-driven tumors covered most key signaling pathways and biological processes. Strikingly, the Wnt/β-catenin pathway was highly mutated (48 variants detected in 46% of the EGFR-driven tumors), and its variant number topped that in the TP53/apoptosis and PI3K-AKT-mTOR pathways. Furthermore, an analysis of mutation distribution revealed a differential association pattern of gene mutations between EGFR exon 19del and EGFR L858R. Our results confirm the aggressive nature of the oncogenic EGFR-driven tumors and reassure that a combinational strategy should have advantages over an EGFR-targeted monotherapy and holds great promise for overcoming drug resistance.

Systemic Regulation of RAS/MAPK Signaling by the Serotonin Metabolite 5-HIAA.

PubMed

Schmid, Tobias; Snoek, L Basten; Fröhli, Erika; van der Bent, M Leontien; Kammenga, Jan; Hajnal, Alex

2015-05-01

Human cancer is caused by the interplay of mutations in oncogenes and tumor suppressor genes and inherited variations in cancer susceptibility genes. While many of the tumor initiating mutations are well characterized, the effect of genetic background variation on disease onset and progression is less understood. We have used C. elegans genetics to identify genetic modifiers of the oncogenic RAS/MAPK signaling pathway. Quantitative trait locus analysis of two highly diverged C. elegans isolates combined with allele swapping experiments identified the polymorphic monoamine oxidase A (MAOA) gene amx-2 as a negative regulator of RAS/MAPK signaling. We further show that the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), which is a product of MAOA catalysis, systemically inhibits RAS/MAPK signaling in different organs of C. elegans. Thus, MAOA activity sets a global threshold for MAPK activation by controlling 5-HIAA levels. To our knowledge, 5-HIAA is the first endogenous small molecule that acts as a systemic inhibitor of RAS/MAPK signaling.

NMR 1H,13C, 15N backbone and 13C side chain resonance assignment of the G12C mutant of human K-Ras bound to GDP.

PubMed

Sharma, Alok K; Lee, Seung-Joo; Rigby, Alan C; Townson, Sharon A

2018-05-02

K-Ras is a key driver of oncogenesis, accounting for approximately 80% of Ras-driven human cancers. The small GTPase cycles between an inactive, GDP-bound and an active, GTP-bound state, regulated by guanine nucleotide exchange factors and GTPase activating proteins, respectively. Activated K-Ras regulates cell proliferation, differentiation and survival by signaling through several effector pathways, including Raf-MAPK. Oncogenic mutations that impair the GTPase activity of K-Ras result in a hyperactivated state, leading to uncontrolled cellular proliferation and tumorogenesis. A cysteine mutation at glycine 12 is commonly found in K-Ras associated cancers, and has become a recent focus for therapeutic intervention. We report here 1 H N, 15 N, and 13 C resonance assignments for the 19.3 kDa (aa 1-169) human K-Ras protein harboring an oncogenic G12C mutation in the GDP-bound form (K-RAS G12C-GDP ), using heteronuclear, multidimensional NMR spectroscopy. Backbone 1 H- 15 N correlations have been assigned for all non-proline residues, except for the first methionine residue.

Activation of the Lbc Rho Exchange Factor Proto-Oncogene by Truncation of an Extended C Terminus That Regulates Transformation and Targeting

PubMed Central

Sterpetti, Paola; Hack, Andrew A.; Bashar, Mariam P.; Park, Brian; Cheng, Sou-De; Knoll, Joan H. M.; Urano, Takeshi; Feig, Larry A.; Toksoz, Deniz

1999-01-01

The human lbc oncogene product is a guanine nucleotide exchange factor that specifically activates the Rho small GTP binding protein, thus resulting in biologically active, GTP-bound Rho, which in turn mediates actin cytoskeletal reorganization, gene transcription, and entry into the mitotic S phase. In order to elucidate the mechanism of onco-Lbc transformation, here we report that while proto- and onco-lbc cDNAs encode identical N-terminal dbl oncogene homology (DH) and pleckstrin homology (PH) domains, proto-Lbc encodes a novel C terminus absent in the oncoprotein that includes a predicted α-helical region homologous to cyto-matrix proteins, followed by a proline-rich region. The lbc proto-oncogene maps to chromosome 15, and onco-lbc represents a fusion of the lbc proto-oncogene N terminus with a short, unrelated C-terminal sequence from chromosome 7. Both onco- and proto-Lbc can promote formation of GTP-bound Rho in vivo. Proto-Lbc transforming activity is much reduced compared to that of onco-Lbc, and a significant increase in transforming activity requires truncation of both the α-helical and proline-rich regions in the proto-Lbc C terminus. Deletion of the chromosome 7-derived C terminus of onco-Lbc does not destroy transforming activity, demonstrating that it is loss of the proto-Lbc C terminus, rather than gain of an unrelated C-terminus by onco-Lbc, that confers transforming activity. Mutations of onco-Lbc DH and PH domains demonstrate that both domains are necessary for full transforming activity. The proto-Lbc product localizes to the particulate (membrane) fraction, while the majority of the onco-Lbc product is cytosolic, and mutations of the PH domain do not affect this localization. The proto-Lbc C-terminus alone localizes predominantly to the particulate fraction, indicating that the C terminus may play a major role in the correct subcellular localization of proto-Lbc, thus providing a mechanism for regulating Lbc oncogenic potential. PMID:9891067

Oncogenic activation of v-kit involves deletion of a putative tyrosine-substrate interaction site.

PubMed

Herbst, R; Munemitsu, S; Ullrich, A

1995-01-19

The transforming gene of the Hardy-Zuckerman-4 strain of feline sarcoma virus, v-kit, arose by transduction of the cellular c-kit gene, which encodes the receptor tyrosine kinase (RTK) p145c-kit. To gain insight into the molecular basis of the v-kit transforming potential, we characterized the feline c-kit by cDNA cloning. Comparison of the feline v-kit and c-kit sequences revealed, in addition to deletions of the extracellular and transmembrane domains, three additional mutations in the v-kit oncogene product: deletion of tyrosine-569 and valine-570, the exchange of aspartate at position 761 to glycine, and replacement of the C-terminal 50 amino acids by five unrelated residues. Examinations of individual v-kit mutations in the context of chimeric receptors yielded inhibitory effects for some mutants on both autophosphorylation and substrate phosphorylation functions. In contrast, deletion of tyrosine-569 and valine-570 significantly enhanced transforming and mitogenic activities of p145c-kit, while the other mutations had no significant effects. Conservation in subclass III RTKs and the identification of the corresponding residue in beta PDGF-R, Y579, as a binding site for src family tyrosine kinases suggests an important role for Y568 in kit signal regulation and the definition of its oncogenic potential. Repositioning of Y571 by an inframe two codon deletion may be the crucial alteration resulting in enhancement of v-kit oncogenic activity.

Lung cancer in never-smoker Asian females is driven by oncogenic mutations, most often involving EGFR

PubMed Central

Choi, Hye Joo; Lee, Jinseon; Jung, Kyungsoo; Irwin, Darry; Liu, Xiao; Lira, Maruja E.; Mao, Mao; Kim, Hong Kwan; Choi, Yong Soo; Shim, Young Mog; Park, Woong Yang; Choi, Yoon-La; Kim, Jhingook

2015-01-01

The aim of this study was to determine the distribution of known oncogenic driver mutations in female never-smoker Asian patients with lung adenocarcinoma. We analyzed 214 mutations across 26 lung cancer-associated genes and three fusion genes using the MassARRAY® LungCarta Panel and the ALK, ROS1, and RET fusion assays in 198 consecutively resected lung adenocarcinomas from never-smoker females at a single institution. EGFR mutation, which was the most frequent driver gene mutation, was detected in 124 (63%) cases. Mutation of ALK, KRAS, PIK3CA, ERBB2, BRAF, ROS1, and RET genesoccurred in 7%, 4%, 2.5%, 1.5%, 1%, 1%, and 1% of cases, respectively. Thus, 79% of lung adenocarcinomas from never-smoker females harbored well-known oncogenic mutations. Mucinous adenocarcinomas tended to have a lower frequency of known driver gene mutations than other histologic subtypes. EGFR mutation was associated with older age and a predominantly acinar pattern, while ALK rearrangement was associated with younger age and a predominantly solid pattern. Lung cancer in never-smoker Asian females is a distinct entity, with the majority of these cancers developing from oncogenic mutations. PMID:25760072

Fibroblast growth factor 23 in oncogenic osteomalacia and X-linked hypophosphatemia.

PubMed

Jonsson, Kenneth B; Zahradnik, Richard; Larsson, Tobias; White, Kenneth E; Sugimoto, Toshitsugu; Imanishi, Yasuo; Yamamoto, Takehisa; Hampson, Geeta; Koshiyama, Hiroyuki; Ljunggren, Osten; Oba, Koichi; Yang, In Myung; Miyauchi, Akimitsu; Econs, Michael J; Lavigne, Jeffrey; Jüppner, Harald

2003-04-24

Mutations in fibroblast growth factor 23 (FGF-23) cause autosomal dominant hypophosphatemic rickets. Clinical and laboratory findings in this disorder are similar to those in oncogenic osteomalacia, in which tumors abundantly express FGF-23 messenger RNA, and to those in X-linked hypophosphatemia, which is caused by inactivating mutations in a phosphate-regulating endopeptidase called PHEX. Recombinant FGF-23 induces phosphaturia and hypophosphatemia in vivo, suggesting that it has a role in phosphate regulation. To determine whether FGF-23 circulates in healthy persons and whether it is elevated in those with oncogenic osteomalacia or X-linked hypophosphatemia, an immunometric assay was developed to measure it. Using affinity-purified, polyclonal antibodies against [Tyr223]FGF-23(206-222)amide and [Tyr224]FGF-23(225-244)amide, we developed a two-site enzyme-linked immunosorbent assay that detects equivalently recombinant human FGF-23, the mutant form in which glutamine is substituted for arginine at position 179 (R179Q), and synthetic human FGF-23(207-244)amide. Plasma or serum samples from 147 healthy adults (mean [+/-SD] age, 48.4+/-19.6 years) and 26 healthy children (mean age, 10.9+/-5.5 years) and from 17 patients with oncogenic osteomalacia (mean age, 43.0+/-13.3 years) and 21 patients with X-linked hypophosphatemia (mean age, 34.9+/-17.2 years) were studied. Mean FGF-23 concentrations in the healthy adults and children were 55+/-50 and 69+/-36 reference units (RU) per milliliter, respectively. Four patients with oncogenic osteomalacia had concentrations ranging from 426 to 7970 RU per milliliter, which normalized after tumor resection. FGF-23 concentrations were 481+/-528 RU per milliliter in those with suspected oncogenic osteomalacia and 353+/-510 RU per milliliter (range, 31 to 2335) in those with X-linked hypophosphatemia. FGF-23 is readily detectable in the plasma or serum of healthy persons and can be markedly elevated in those with oncogenic osteomalacia or X-linked hypophosphatemia, suggesting that this growth factor has a role in phosphate homeostasis. FGF-23 measurements might improve the management of phosphate-wasting disorders. Copyright 2003 Massachusetts Medical Society

HER2 missense mutations have distinct effects on oncogenic signaling and migration

PubMed Central

Zabransky, Daniel J.; Yankaskas, Christopher L.; Cochran, Rory L.; Wong, Hong Yuen; Croessmann, Sarah; Chu, David; Kavuri, Shyam M.; Red Brewer, Monica; Rosen, D. Marc; Dalton, W. Brian; Cimino-Mathews, Ashley; Cravero, Karen; Button, Berry; Kyker-Snowman, Kelly; Cidado, Justin; Erlanger, Bracha; Parsons, Heather A.; Manto, Kristen M.; Bose, Ron; Lauring, Josh; Arteaga, Carlos L.; Konstantopoulos, Konstantinos; Park, Ben Ho

2015-01-01

Recurrent human epidermal growth factor receptor 2 (HER2) missense mutations have been reported in human cancers. These mutations occur primarily in the absence of HER2 gene amplification such that most HER2-mutant tumors are classified as “negative” by FISH or immunohistochemistry assays. It remains unclear whether nonamplified HER2 missense mutations are oncogenic and whether they are targets for HER2-directed therapies that are currently approved for the treatment of HER2 gene-amplified breast cancers. Here we functionally characterize HER2 kinase and extracellular domain mutations through gene editing of the endogenous loci in HER2 nonamplified human breast epithelial cells. In in vitro and in vivo assays, the majority of HER2 missense mutations do not impart detectable oncogenic changes. However, the HER2 V777L mutation increased biochemical pathway activation and, in the context of a PIK3CA mutation, enhanced migratory features in vitro. However, the V777L mutation did not alter in vivo tumorigenicity or sensitivity to HER2-directed therapies in proliferation assays. Our results suggest the oncogenicity and potential targeting of HER2 missense mutations should be considered in the context of cooperating genetic alterations and provide previously unidentified insights into functional analysis of HER2 mutations and strategies to target them. PMID:26508629

SomInaClust: detection of cancer genes based on somatic mutation patterns of inactivation and clustering.

PubMed

Van den Eynden, Jimmy; Fierro, Ana Carolina; Verbeke, Lieven P C; Marchal, Kathleen

2015-04-23

With the advances in high throughput technologies, increasing amounts of cancer somatic mutation data are being generated and made available. Only a small number of (driver) mutations occur in driver genes and are responsible for carcinogenesis, while the majority of (passenger) mutations do not influence tumour biology. In this study, SomInaClust is introduced, a method that accurately identifies driver genes based on their mutation pattern across tumour samples and then classifies them into oncogenes or tumour suppressor genes respectively. SomInaClust starts from the observation that oncogenes mainly contain mutations that, due to positive selection, cluster at similar positions in a gene across patient samples, whereas tumour suppressor genes contain a high number of protein-truncating mutations throughout the entire gene length. The method was shown to prioritize driver genes in 9 different solid cancers. Furthermore it was found to be complementary to existing similar-purpose methods with the additional advantages that it has a higher sensitivity, also for rare mutations (occurring in less than 1% of all samples), and it accurately classifies candidate driver genes in putative oncogenes and tumour suppressor genes. Pathway enrichment analysis showed that the identified genes belong to known cancer signalling pathways, and that the distinction between oncogenes and tumour suppressor genes is biologically relevant. SomInaClust was shown to detect candidate driver genes based on somatic mutation patterns of inactivation and clustering and to distinguish oncogenes from tumour suppressor genes. The method could be used for the identification of new cancer genes or to filter mutation data for further data-integration purposes.

Thrombopoietin/MPL participates in initiating and maintaining RUNX1-ETO acute myeloid leukemia via PI3K/AKT signaling

PubMed Central

Pulikkan, John Anto; Madera, Dmitri; Xue, Liting; Bradley, Paul; Landrette, Sean Francis; Kuo, Ya-Huei; Abbas, Saman; Zhu, Lihua Julie; Valk, Peter

2012-01-01

Oncogenic mutations in components of cytokine signaling pathways elicit ligand-independent activation of downstream signaling, enhancing proliferation and survival in acute myeloid leukemia (AML). The myeloproliferative leukemia virus oncogene, MPL, a homodimeric receptor activated by thrombopoietin (THPO), is mutated in myeloproliferative disorders but rarely in AML. Here we show that wild-type MPL expression is increased in a fraction of human AML samples expressing RUNX1-ETO, a fusion protein created by chromosome translocation t(8;21), and that up-regulation of Mpl expression in mice induces AML when coexpressed with RUNX1-ETO. The leukemic cells are sensitive to THPO, activating survival and proliferative responses. Mpl expression is not regulated by RUNX1-ETO in mouse hematopoietic progenitors or leukemic cells. Moreover, we find that activation of PI3K/AKT but not ERK/MEK pathway is a critical mediator of the MPL-directed antiapoptotic function in leukemic cells. Hence, this study provides evidence that up-regulation of wild-type MPL levels promotes leukemia development and maintenance through activation of the PI3K/AKT axis, and suggests that inhibitors of this axis could be effective for treatment of MPL-positive AML. PMID:22613795

Thrombopoietin/MPL participates in initiating and maintaining RUNX1-ETO acute myeloid leukemia via PI3K/AKT signaling.

PubMed

Pulikkan, John Anto; Madera, Dmitri; Xue, Liting; Bradley, Paul; Landrette, Sean Francis; Kuo, Ya-Huei; Abbas, Saman; Zhu, Lihua Julie; Valk, Peter; Castilla, Lucio Hernán

2012-07-26

Oncogenic mutations in components of cytokine signaling pathways elicit ligand-independent activation of downstream signaling, enhancing proliferation and survival in acute myeloid leukemia (AML). The myeloproliferative leukemia virus oncogene, MPL, a homodimeric receptor activated by thrombopoietin (THPO), is mutated in myeloproliferative disorders but rarely in AML. Here we show that wild-type MPL expression is increased in a fraction of human AML samples expressing RUNX1-ETO, a fusion protein created by chromosome translocation t(8;21), and that up-regulation of Mpl expression in mice induces AML when coexpressed with RUNX1-ETO. The leukemic cells are sensitive to THPO, activating survival and proliferative responses. Mpl expression is not regulated by RUNX1-ETO in mouse hematopoietic progenitors or leukemic cells. Moreover, we find that activation of PI3K/AKT but not ERK/MEK pathway is a critical mediator of the MPL-directed antiapoptotic function in leukemic cells. Hence, this study provides evidence that up-regulation of wild-type MPL levels promotes leukemia development and maintenance through activation of the PI3K/AKT axis, and suggests that inhibitors of this axis could be effective for treatment of MPL-positive AML.

RSK regulates activated BRAF signalling to mTORC1 and promotes melanoma growth

PubMed Central

Zindy, Pierre-Joachim; Saba-El-Leil, Marc; Lavoie, Geneviève; Dandachi, Farah; Baptissart, Marine; Borden, Katherine L. B.; Meloche, Sylvain; Roux, Philippe P.

2015-01-01

The Ras/mitogen-activated protein kinase (MAPK) signalling cascade regulates various biological functions, including cell growth, proliferation and survival. As such, this pathway is often deregulated in cancer, including melanomas, which frequently harbour activating mutations in the NRAS and BRAF oncogenes. Hyperactive MAPK signalling is known to promote protein synthesis, but the mechanisms by which this occurs remain poorly understood. Here, we show that expression of oncogenic forms of Ras and Raf promotes the constitutive activation of the mammalian target of rapamycin (mTOR). Using pharmacological inhibitors and RNA interference we find that the MAPK-activated protein kinase RSK (p90 ribosomal S6 kinase) is partly required for these effects. Using melanoma cell lines carrying activating BRAF mutations we show that ERK/RSK signalling regulates assembly of the translation initiation complex and polysome formation, as well as the translation of growth-related mRNAs containing a 5’ terminal oligopyrimidine (TOP) motif. Accordingly, we find that RSK inhibition abrogates tumour growth in mice. Our findings indicate that RSK may be a valuable therapeutic target for the treatment of tumours characterized by deregulated MAPK signalling, such as melanoma. PMID:22797077

Comprehensive profiling and quantitation of oncogenic mutations in non-small cell lung carcinoma using single-molecule amplification and re-sequencing technology.

PubMed

Shi, Jian; Yuan, Meng; Wang, Zhan-Dong; Xu, Xiao-Li; Hong, Lei; Sun, Shenglin

2017-02-01

The carcinogenesis of non-small cell lung carcinoma has been found to associate with activating and resistant mutations in the tyrosine kinase domain of specific oncogenes. Here, we assessed the type, frequency, and abundance of epithelial growth factor receptor, KRAS, BRAF, and ALK mutations in 154 non-small cell lung carcinoma specimens using single-molecule amplification and re-sequencing technology. We found that epithelial growth factor receptor mutations were the most prevalent (44.2%), followed by KRAS (18.8%), ALK (7.8%), and BRAF (5.8%) mutations. The type and abundance of the mutations in tumor specimens appeared to be heterogeneous. Thus, we conclude that identification of clinically significant oncogenic mutations may improve the classification of patients and provide valuable information for determination of the therapeutic strategies.

PIK3CA oncogenic mutations represent a major mechanism of resistance to trastuzumab in HER2/neu overexpressing uterine serous carcinomas

PubMed Central

Black, Jonathan D; Lopez, Salvatore; Cocco, Emiliano; Bellone, Stefania; Altwerger, Gary; Schwab, Carlton L; English, Diana P; Bonazzoli, Elena; Predolini, Federica; Ferrari, Francesca; Ratner, Elena; Silasi, Dan-Arin; Azodi, Masoud; Schwartz, Peter E; Santin, Alessandro D

2015-01-01

Objectives: We evaluated the role of PIK3CA-mutations as mechanism of resistance to trastuzumab in primary HER2/neu-amplified uterine-serous-carcinoma (USC) cell lines. Methods: Fifteen whole-exome-sequenced USC cell lines were tested for HER2/neu-amplification and PIK3CA-mutations. Four HER2/neu-amplified USC (2-harbouring wild-type-PIK3CA-genes and 2-harbouring oncogenic-PIK3CA-mutations) were evaluated in in vitro dose-titration-proliferation-assays, cell-viability and HER2 and S6-protein-phosphorylation after exposure to trastuzumab. USC harbouring wild-type-PIK3CA were transfected with plasmids encoding oncogenic PIK3CA-mutations (i.e., H1047R/R93Q) and exposed to trastuzumab. Finally, trastuzumab efficacy was tested by using two USC xenograft mouse models. Results: Seven out of fifteen (46%) of the USC cell lines were HER2/neu-amplified by fluorescence in situ hybridisation. Within these tumours four out of seven (57%) were found to harbour oncogenic PIK3CA-mutations vs two out of eight (25%) of the HER2/neu not amplified cell lines (P=0.01). HER2/neu-amplified/PIK3CA-mutated USC were highly resistant to trastuzumab when compared with HER2/neu-amplified/wild-type-PIK3CA cell lines (P=0.02). HER2/neu-amplified/PIK3CA wild-type cell lines transfected with oncogenic PIK3CA-mutations increased their resistance to trastuzumab (P<0.0001). Trastuzumab was effective in reducing tumour growth (P=0.001) and improved survival (P=0.0001) in mouse xenografts harbouring HER2-amplified/PIK3CA wild-type USC but not in HER2-amplified/PIK3CA-mutated tumours. Conclusions: Oncogenic PIK3CA mutations are common in HER2/neu-amplified USC and may constitute a major mechanism of resistance to trastuzumab treatment. PMID:26325104

PIK3CA oncogenic mutations represent a major mechanism of resistance to trastuzumab in HER2/neu overexpressing uterine serous carcinomas.

PubMed

Black, Jonathan D; Lopez, Salvatore; Cocco, Emiliano; Bellone, Stefania; Altwerger, Gary; Schwab, Carlton L; English, Diana P; Bonazzoli, Elena; Predolini, Federica; Ferrari, Francesca; Ratner, Elena; Silasi, Dan-Arin; Azodi, Masoud; Schwartz, Peter E; Santin, Alessandro D

2015-09-29

We evaluated the role of PIK3CA-mutations as mechanism of resistance to trastuzumab in primary HER2/neu-amplified uterine-serous-carcinoma (USC) cell lines. Fifteen whole-exome-sequenced USC cell lines were tested for HER2/neu-amplification and PIK3CA-mutations. Four HER2/neu-amplified USC (2-harbouring wild-type-PIK3CA-genes and 2-harbouring oncogenic-PIK3CA-mutations) were evaluated in in vitro dose-titration-proliferation-assays, cell-viability and HER2 and S6-protein-phosphorylation after exposure to trastuzumab. USC harbouring wild-type-PIK3CA were transfected with plasmids encoding oncogenic PIK3CA-mutations (i.e., H1047R/R93Q) and exposed to trastuzumab. Finally, trastuzumab efficacy was tested by using two USC xenograft mouse models. Seven out of fifteen (46%) of the USC cell lines were HER2/neu-amplified by fluorescence in situ hybridisation. Within these tumours four out of seven (57%) were found to harbour oncogenic PIK3CA-mutations vs two out of eight (25%) of the HER2/neu not amplified cell lines (P=0.01). HER2/neu-amplified/PIK3CA-mutated USC were highly resistant to trastuzumab when compared with HER2/neu-amplified/wild-type-PIK3CA cell lines (P=0.02). HER2/neu-amplified/PIK3CA wild-type cell lines transfected with oncogenic PIK3CA-mutations increased their resistance to trastuzumab (P<0.0001). Trastuzumab was effective in reducing tumour growth (P=0.001) and improved survival (P=0.0001) in mouse xenografts harbouring HER2-amplified/PIK3CA wild-type USC but not in HER2-amplified/PIK3CA-mutated tumours. Oncogenic PIK3CA mutations are common in HER2/neu-amplified USC and may constitute a major mechanism of resistance to trastuzumab treatment.

Occurrence of phaeochromocytoma tumours in RET mutation carriers - a single-centre study.

PubMed

Kotecka-Blicharz, Agnieszka; Hasse-Lazar, Kornelia; Jurecka-Lubieniecka, Beata; Pawlaczek, Agnieszka; Oczko-Wojciechowska, Małgorzata; Bugajska, Beata; Ledwon, Aleksandra; Król, Aleksandra; Michalik, Barbara; Jarząb, Barbara

2016-01-01

Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant genetic syndrome caused by germline mutation in RET proto-oncogene. The most common mutations are in a cysteine rich domain. Phaeochromocytoma will develop in approximately 50% of RET proto-oncogene carriers. The studied population consisted of 228 RET proto-oncogene mutation carriers. Monitoring for the diagnosis of phaeochromocytoma was carried out in all patients with established genetic status. Mean time of follow up was 138 months. Surveillance consisted of periodically performed clinical evaluation, 24-hour urinary determinations of total metanephrines complementary with imaging (CT, MR, MIBG scintigraphy). Phaeochromocytoma developed in 41 patients (18% of all RET proto-oncogene mutations carriers). The mean age of diagnosis for the whole cohort was 43 years. In eight cases phaeochromocytoma was the first manifestation of the MEN 2 syndrome. Only eight (20%) patients were symptomatic at diagnosis of phaeochromocytoma. The mean size of the tumour was 4.3 cm. There was no extra-adrenal localisation. We observed one case of malignant phaeochromocytoma. In patients with MEN 2 syndrome phaeochromocytomas are usually benign adrenal tumours with high risk of bilateral development. Taking to account the latter risk and non-specific clinical manifestation of the neoplasm it is mandatory to screen all RET proto-oncogene mutations carriers for phaeochromocytoma.

KRASG12D expression in lung-resident myeloid cells promotes pulmonary LCH-like neoplasm sensitive to statin treatment

PubMed Central

Giblett, Susan; Pritchard, Catrin

2017-01-01

Langerhans cell histiocytosis (LCH) is a rare histiocytic neoplasm associated with somatic mutations in the genes involved in the RAF/MEK/extracellular signal-regulated kinase (ERK) signaling pathway. Recently, oncogenic mutations in NRAS/KRAS, upstream regulators of the RAF/MEK/ERK pathway, have been reported in pulmonary, but not in nonpulmonary, LCH cases, suggesting organ-specific contribution of oncogenic RAS to LCH pathogenesis. Using a mouse model expressing KRASG12D in the lung by nasal delivery of adenoviral Cre recombinase (Cre), here we show that KRASG12D expression in lung-resident myeloid cells induces pulmonary LCH-like neoplasms composed of pathogenic CD11chighF4/80+CD207+ cells. The pathogenic cells were mitotically inactive, but proliferating precursors were detected in primary cultures of lung tissue. These precursors were derived, at least in part, from CD11cdimCD11bintGr1− lung-resident monocytic cells transformed by KRASG12D. In contrast, BRAFV600E expression induced by the same method failed to develop LCH-like neoplasms, suggesting that each oncogene may initiate pulmonary LCH by transforming different types of lung-resident myeloid cells. In vivo treatment of the KRASG12D-induced LCH-like mouse with the cholesterol-lowering drug atorvastatin ameliorated the pathology, implicating statins as potential therapeutics against a subset of pulmonary LCH. PMID:28550040

ROS1 fusions rarely overlap with other oncogenic drivers in non-small cell lung cancer

PubMed Central

Lin, Jessica J.; Ritterhouse, Lauren L.; Ali, Siraj M.; Bailey, Mark; Schrock, Alexa B.; Gainor, Justin F.; Ferris, Lorin A.; Mino-Kenudson, Mari; Miller, Vincent A.; Iafrate, Anthony J.; Lennerz, Jochen K.; Shaw, Alice T.

2017-01-01

Introduction Chromosomal rearrangements involving the ROS proto-oncogene 1 receptor tyrosine kinase gene (ROS1) define a distinct molecular subset of non-small cell lung cancer (NSCLC) with sensitivity to ROS1 inhibitors. Recent reports have suggested a significant overlap between ROS1 fusions and other oncogenic driver alterations, including mutations in epidermal growth factor receptor (EGFR) and KRAS proto-oncogene (KRAS). Methods We identified patients at our institution with ROS1-rearranged NSCLC who had undergone testing for genetic alterations in additional oncogenes, including EGFR, KRAS, and anaplastic lymphoma kinase (ALK). Clinicopathologic features and genetic testing results were reviewed. We also examined a separate database of ROS1-rearranged NSCLCs identified through a commercial FoundationOne assay. Results Among 62 patients with ROS1-rearranged NSCLC evaluated at our institution, none harbored concurrent ALK fusions (0%) or EGFR activating mutations (0%). KRAS mutations were detected in two cases (3.2%), one of which harbored a concurrent non-canonical KRAS I24N mutation of unknown biological significance. In a separate ROS1 FISH-positive case, targeted sequencing failed to confirm a ROS1 fusion, but instead identified a KRAS G13D mutation. No concurrent mutations in BRAF, ERBB2, PIK3CA, AKT1, or MAP2K1 were detected. Analysis of an independent dataset of 166 ROS1-rearranged NSCLCs identified by FoundationOne demonstrated rare cases with co-occurring driver mutations in EGFR (1/166) and KRAS (3/166), and no cases with co-occurring ROS1 and ALK rearrangements. Conclusions ROS1 rearrangements rarely overlap with alterations in EGFR, KRAS, ALK, or other targetable oncogenes in NSCLC. PMID:28088512

Regulation of Stat5 by FAK and PAK1 in Oncogenic FLT3 and KIT driven Leukemogenesis

PubMed Central

Chatterjee, Anindya; Ghosh, Joydeep; Ramdas, Baskar; Mali, Raghuveer Singh; Martin, Holly; Kobayashi, Michihiro; Vemula, Sasidhar; Canela, Victor H.; Waskow, Emily R.; Visconte, Valeria; Tiu, Ramon V.; Smith, Catherine C.; Shah, Neil; Bunting, Kevin D.; Boswell, H. Scott; Liu, Yan; Chan, Rebecca J.; Kapur, Reuben

2015-01-01

SUMMARY Oncogenic mutations of FLT3 and KIT receptors are associated with poor survival in patients with acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPN) and currently available drugs are largely ineffective. Although Stat5 has been implicated in regulating several myeloid and lymphoid malignancies, how precisely Stat5 regulates leukemogenesis, including its nuclear translocation to induce gene transcription is poorly understood. In leukemic cells, we show constitutive activation of focal adhesion kinase (FAK), whose inhibition represses leukemogenesis. Downstream of FAK, activation of Rac1 is regulated by RacGEF Tiam1, whose inhibition prolongs the survival of leukemic mice. Inhibition of the Rac1 effector PAK1 prolongs the survival of leukemic mice in part by inhibiting the nuclear translocation of Stat5. These results reveal a leukemic pathway involving FAK/Tiam1/Rac1/PAK1 and demonstrate an essential role for these signaling molecules in regulating the nuclear translocation of Stat5 in leukemogenesis. PMID:25456130

Differential KrasV12 protein levels control a switch regulating lung cancer cell morphology and motility

PubMed Central

Schäfer, C.; Mohan, A.; Burford, W.; Driscoll, M. K.; Ludlow, A. T.; Wright, W. E.; Shay, J. W.; Danuser, G.

2016-01-01

Introduction Oncogenic Kras mutations are important drivers of lung cancer development and metastasis. They are known to activate numerous cellular signaling pathways implicated in enhanced proliferation, survival, tumorigenicity and motility during malignant progression. Objectives Most previous studies of Kras in cancer have focused on the comparison of cell states in the absence or presence of oncogenic Kras mutations. Here we show that differential expression of the constitutively active mutation KrasV12 has profound effects on cell morphology and motility that drive metastatic processes. Methods The study relies on lung cancer cell transformation models, patient-derived lung cancer cell lines, and human lung tumor sections combined with molecular biology techniques, live-cell imaging and staining methods. Results Our analysis shows two cell functional states driven by KrasV12 protein levels: a non-motile state associated with high KrasV12 levels and tumorigenicity, and a motile state associated with low KrasV12 levels and cell dissemination. Conversion between the states is conferred by differential activation of a mechano-sensitive double-negative feedback between KrasV12/ERK/Myosin II and matrix-adhesion signaling. KrasV12 expression levels change upon cues such as hypoxia and integrin-mediated cell-matrix adhesion, rendering KrasV12 levels an integrator of micro-environmental signals that translate into cellular function. By live cell imaging of tumor models we observe shedding of mixed high and low KrasV12 expressers forming multi-functional collectives with potentially optimal metastatic properties composed of a highly mobile and a highly tumorigenic unit. Discussion Together these data highlight previously unappreciated roles for the quantitative effects of expression level variation of oncogenic signaling molecules in conferring fundamental alterations in cell function regulation required for cancer progression. PMID:29057096

Tyrosine 842 in the activation loop is required for full transformation by the oncogenic mutant FLT3-ITD.

PubMed

Kazi, Julhash U; Chougule, Rohit A; Li, Tianfeng; Su, Xianwei; Moharram, Sausan A; Rupar, Kaja; Marhäll, Alissa; Gazi, Mohiuddin; Sun, Jianmin; Zhao, Hui; Rönnstrand, Lars

2017-07-01

The type III receptor tyrosine kinase FLT3 is frequently mutated in acute myeloid leukemia. Oncogenic FLT3 mutants display constitutive activity leading to aberrant cell proliferation and survival. Phosphorylation on several critical tyrosine residues is known to be essential for FLT3 signaling. Among these tyrosine residues, Y842 is located in the so-called activation loop. The position of this tyrosine residue is well conserved in all receptor tyrosine kinases. It has been reported that phosphorylation of the activation loop tyrosine is critical for catalytic activity for some but not all receptor tyrosine kinases. The role of Y842 residue in FLT3 signaling has not yet been studied. In this report, we show that Y842 is not important for FLT3 activation or ubiquitination but plays a critical role in regulating signaling downstream of the receptor as well as controlling receptor stability. We found that mutation of Y842 in the FLT3-ITD oncogenic mutant background reduced cell viability and increased apoptosis. Furthermore, the introduction of the Y842 mutation in the FLT3-ITD background led to a dramatic reduction in in vitro colony forming capacity. Additionally, mice injected with cells expressing FLT3-ITD/Y842F displayed a significant delay in tumor formation, compared to FLT3-ITD expressing cells. Microarray analysis comparing gene expression regulated by FLT3-ITD versus FLT3-ITD/Y842F demonstrated that mutation of Y842 causes suppression of anti-apoptotic genes. Furthermore, we showed that cells expressing FLT3-ITD/Y842F display impaired activity of the RAS/ERK pathway due to reduced interaction between FLT3 and SHP2 leading to reduced SHP2 activation. Thus, we suggest that Y842 is critical for FLT3-mediated RAS/ERK signaling and cellular transformation.

Response of head and neck squamous cell carcinoma cells carrying PIK3CA mutations to selected targeted therapies.

PubMed

Wirtz, Eric D; Hoshino, Daisuke; Maldonado, Anthony T; Tyson, Darren R; Weaver, Alissa M

2015-06-01

The PIK3CA mutation is one of the most common mutations in head and neck squamous cell carcinoma (HNSCC). Through this research we attempt to elicit the role of oncogene dependence and effects of targeted therapy on this PIK3CA mutation. (1) To determine the role of oncogene dependence on PIK3CA-one of the more common and targetable oncogenes in HNSCC, and (2) to evaluate the consequence of this oncogene on the effectiveness of newly developed targeted therapies. This was a cell culture-based, in vitro study performed at an academic research laboratory assessing the viability of PIK3CA-mutated head and neck cell lines when treated with targeted therapy. PIK3CA-mutated head and neck cell lines were treated with 17-AAG, GDC-0941, trametinib, and BEZ-235. Assessment of cell viability of HNSCC cell lines characterized for PIK3CA mutations or SCC25 cells engineered to express the PIK3CA hotspot mutations E545K or H1047R. Surprisingly, in engineered cell lines, the hotspot E545K and H1047R mutations conferred increased, rather than reduced, IC50 assay measurements when treated with the respective HSP90, PI3K, and MEK inhibitors, 17-AAG, GDC-0941, and trametinib, compared with the SCC25 control cell lines. When treated with BEZ-235, H1047R-expressing cell lines showed increased sensitivity to inhibition compared with control, whereas those expressing E545K showed slightly increased sensitivity of unclear significance. (1) The PIK3CA mutations within our engineered cell model did not lead to enhanced oncogene-dependent cell death when treated with direct inhibition of the PI3K enzyme yet did show increased sensitivity compared with control with dual PI3K/mTOR inhibition. (2) Oncogene addiction to PIK3CA hotspot mutations, if it occurs, is likely to evolve in vivo in the context of additional molecular changes that remain to be identified. Additional study is required to develop new model systems and approaches to determine the role of targeted therapy in the treatment of PI3K-overactive HNSCC tumors.

DNA replication stress as a hallmark of cancer.

PubMed

Macheret, Morgane; Halazonetis, Thanos D

2015-01-01

Human cancers share properties referred to as hallmarks, among which sustained proliferation, escape from apoptosis, and genomic instability are the most pervasive. The sustained proliferation hallmark can be explained by mutations in oncogenes and tumor suppressors that regulate cell growth, whereas the escape from apoptosis hallmark can be explained by mutations in the TP53, ATM, or MDM2 genes. A model to explain the presence of the three hallmarks listed above, as well as the patterns of genomic instability observed in human cancers, proposes that the genes driving cell proliferation induce DNA replication stress, which, in turn, generates genomic instability and selects for escape from apoptosis. Here, we review the data that support this model, as well as the mechanisms by which oncogenes induce replication stress. Further, we argue that DNA replication stress should be considered as a hallmark of cancer because it likely drives cancer development and is very prevalent.

Understanding the biology of melanoma and therapeutic implications

PubMed Central

Sullivan, Ryan J; Fisher, David E

2014-01-01

From 1976 – 2010, the US FDA approved only two medications for the treatment of metastatic melanoma, dacarbazine and high-dose interleukin 2. Between 2011–13, four agents were approved (ipilimumab, vemurafenib, dabrafenib, trametinib) and other therapies have shown great promise in clinical trials. This startling progress has been made possible by the groundbreaking efforts of basic scientists and the vision and innovation of translational and clinical investigators. Fundamental discoveries such as the identification of oncogenic mutations in the majority melanomas, the elucidation of the molecular signaling resultant from these mutations, and the revelation that a number of cell surface molecules serve as regulators of immune activation, have all been instrumental to this progress. This chapter provides a summary of the molecular pathogenesis of melanoma by reviewing the relevant melanocyte biology and molecular signaling used by melanoma, describes the current efforts to target oncogene driven signaling, and presents the rationale for combining immune and molecular targeting. PMID:24880940

Reverse engineering of TLX oncogenic transcriptional networks identifies RUNX1 as tumor suppressor in T-ALL.

PubMed

Della Gatta, Giusy; Palomero, Teresa; Perez-Garcia, Arianne; Ambesi-Impiombato, Alberto; Bansal, Mukesh; Carpenter, Zachary W; De Keersmaecker, Kim; Sole, Xavier; Xu, Luyao; Paietta, Elisabeth; Racevskis, Janis; Wiernik, Peter H; Rowe, Jacob M; Meijerink, Jules P; Califano, Andrea; Ferrando, Adolfo A

2012-02-26

The TLX1 and TLX3 transcription factor oncogenes have a key role in the pathogenesis of T cell acute lymphoblastic leukemia (T-ALL). Here we used reverse engineering of global transcriptional networks to decipher the oncogenic regulatory circuit controlled by TLX1 and TLX3. This systems biology analysis defined T cell leukemia homeobox 1 (TLX1) and TLX3 as master regulators of an oncogenic transcriptional circuit governing T-ALL. Notably, a network structure analysis of this hierarchical network identified RUNX1 as a key mediator of the T-ALL induced by TLX1 and TLX3 and predicted a tumor-suppressor role for RUNX1 in T cell transformation. Consistent with these results, we identified recurrent somatic loss-of-function mutations in RUNX1 in human T-ALL. Overall, these results place TLX1 and TLX3 at the top of an oncogenic transcriptional network controlling leukemia development, show the power of network analyses to identify key elements in the regulatory circuits governing human cancer and identify RUNX1 as a tumor-suppressor gene in T-ALL.

Suppressor of cytokine signaling 1 interacts with oncogenic lymphocyte-specific protein tyrosine kinase.

PubMed

Venkitachalam, Srividya; Chueh, Fu-Yu; Leong, King-Fu; Pabich, Samantha; Yu, Chao-Lan

2011-03-01

Lymphocyte-specific protein tyrosine kinase (Lck) plays a key role in T cell signal transduction and is tightly regulated by phosphorylation and dephosphorylation. Lck can function as an oncoprotein when overexpressed or constantly activated by mutations. Our previous studies showed that Lck-induced cellular transformation could be suppressed by enforced expression of suppressor of cytokine signaling 1 (SOCS1), a SOCS family member involved in the negative feedback control of cytokine signaling. We observed attenuated Lck kinase activity in SOCS1-expressing cells, suggesting an important role of SOCS in regulating Lck functions. It remains largely unknown whether and how SOCS proteins interact with the oncogenic Lck kinase. Here, we report that among four SOCS family proteins, SOCS1, SOCS2, SOCS3 and CIS (cytokine-inducible SH2 domain containing protein), SOCS1 has the highest affinity in binding to the oncogenic Lck kinase. We identified the positive regulatory phosphotyrosine 394 residue in the kinase domain as the key interacting determinant in Lck. Additionally, the Lck kinase domain alone is sufficient to bind SOCS1. While the SH2 domain in SOCS1 is important in its association with the oncogenic Lck kinase, other functional domains may also contribute to overall binding affinity. These findings provide important mechanistic insights into the role of SOCS proteins as tumor suppressors in cells transformed by oncogenic protein tyrosine kinases.

Suppressor of cytokine signaling 1 interacts with oncogenic lymphocyte-specific protein tyrosine kinase

PubMed Central

VENKITACHALAM, SRIVIDYA; CHUEH, FU-YU; LEONG, KING-FU; PABICH, SAMANTHA; YU, CHAO-LAN

2011-01-01

Lymphocyte-specific protein tyrosine kinase (Lck) plays a key role in T cell signal transduction and is tightly regulated by phosphorylation and dephosphorylation. Lck can function as an oncoprotein when overexpressed or constantly activated by mutations. Our previous studies showed that Lck-induced cellular transformation could be suppressed by enforced expression of suppressor of cytokine signaling 1 (SOCS1), a SOCS family member involved in the negative feedback control of cytokine signaling. We observed attenuated Lck kinase activity in SOCS1-expressing cells, suggesting an important role of SOCS in regulating Lck functions. It remains largely unknown whether and how SOCS proteins interact with the oncogenic Lck kinase. Here we report that, among four SOCS family proteins, SOCS1, SOCS2, SOCS3 and CIS (cytokine–inducible SH2 domain containing protein), SOCS1 has the highest affinity in binding to the oncogenic Lck kinase. We identify the positive regulatory phospho-tyrosine 394 residue in the kinase domain as the key interacting determinant in Lck. Additionally, the Lck kinase domain alone is sufficient to bind SOCS1. While the SH2 domain in SOCS1 is important in its association with the oncogenic Lck kinase, other functional domains may also contribute to overall binding affinity. These findings provide important mechanistic insights into the role of SOCS proteins as tumor suppressors in cells transformed by oncogenic protein tyrosine kinases. PMID:21234523

neu mutation in schwannomas induced transplacentally in Syrian golden hamsters by N-nitrosoethylurea: high incidence but low allelic representation.

PubMed

Buzard, G S; Enomoto, T; Hongyo, T; Perantoni, A O; Diwan, B A; Devor, D E; Reed, C D; Dove, L F; Rice, J M

1999-10-01

Peripheral nerve tumors (PNT) and melanomas induced transplacentally on day 14 of gestation in Syrian golden hamsters by N-nitrosoethylurea were analyzed for activated oncogenes by the NIH 3T3 transfection assay, and for mutations in the neu oncogene by direct sequencing, allele-specific oligonucleotide hybridization, MnlI restriction-fragment-length polymorphism, single-strand conformation polymorphism, and mismatch amplification mutation assays. All (67/67) of the PNT, but none of the melanomas, contained a somatic missense T --> A transversion within the neu oncogene transmembrane domain at a site corresponding to that which also occurs in rat schwannomas transplacentally induced by N-nitrosoethylurea. In only 2 of the 67 individual hamster PNT did the majority of tumor cells appear to carry the mutant neu allele, in contrast to comparable rat schwannomas in which it overwhelmingly predominates. The low fraction of hamster tumor cells carrying the mutation was stable through multiple transplantation passages. In the hamster, as in the rat, specific point-mutational activation of the neu oncogene thus constitutes the major pathway for induction of PNT by transplacental exposure to an alkylating agent, but the low allelic representation of mutant neu in hamster PNT suggests a significant difference in mechanism by which the mutant oncogene acts in this species.

Identification and analysis of mutational hotspots in oncogenes and tumour suppressors.

PubMed

Baeissa, Hanadi; Benstead-Hume, Graeme; Richardson, Christopher J; Pearl, Frances M G

2017-03-28

The key to interpreting the contribution of a disease-associated mutation in the development and progression of cancer is an understanding of the consequences of that mutation both on the function of the affected protein and on the pathways in which that protein is involved. Protein domains encapsulate function and position-specific domain based analysis of mutations have been shown to help elucidate their phenotypes. In this paper we examine the domain biases in oncogenes and tumour suppressors, and find that their domain compositions substantially differ. Using data from over 30 different cancers from whole-exome sequencing cancer genomic projects we mapped over one million mutations to their respective Pfam domains to identify which domains are enriched in any of three different classes of mutation; missense, indels or truncations. Next, we identified the mutational hotspots within domain families by mapping small mutations to equivalent positions in multiple sequence alignments of protein domainsWe find that gain of function mutations from oncogenes and loss of function mutations from tumour suppressors are normally found in different domain families and when observed in the same domain families, hotspot mutations are located at different positions within the multiple sequence alignment of the domain. By considering hotspots in tumour suppressors and oncogenes independently, we find that there are different specific positions within domain families that are particularly suited to accommodate either a loss or a gain of function mutation. The position is also dependent on the class of mutation.We find rare mutations co-located with well-known functional mutation hotspots, in members of homologous domain superfamilies, and we detect novel mutation hotspots in domain families previously unconnected with cancer. The results of this analysis can be accessed through the MOKCa database (http://strubiol.icr.ac.uk/extra/MOKCa).

Drug Resistance Missense Mutations in Cancer Are Subject to Evolutionary Constraints

PubMed Central

Friedman, Ran

2013-01-01

Several tumour types are sensitive to deactivation of just one or very few genes that are constantly active in the cancer cells, a phenomenon that is termed ‘oncogene addiction’. Drugs that target the products of those oncogenes can yield a temporary relief, and even complete remission. Unfortunately, many patients receiving oncogene-targeted therapies relapse on treatment. This often happens due to somatic mutations in the oncogene (‘resistance mutations’). ‘Compound mutations’, which in the context of cancer drug resistance are defined as two or more mutations of the drug target in the same clone may lead to enhanced resistance against the most selective inhibitors. Here, it is shown that the vast majority of the resistance mutations occurring in cancer patients treated with tyrosin kinase inhibitors aimed at three different proteins follow an evolutionary pathway. Using bioinformatic analysis tools, it is found that the drug-resistance mutations in the tyrosine kinase domains of Abl1, ALK and exons 20 and 21 of EGFR favour transformations to residues that can be identified in similar positions in evolutionary related proteins. The results demonstrate that evolutionary pressure shapes the mutational landscape in the case of drug-resistance somatic mutations. The constraints on the mutational landscape suggest that it may be possible to counter single drug-resistance point mutations. The observation of relatively many resistance mutations in Abl1, but not in the other genes, is explained by the fact that mutations in Abl1 tend to be biochemically conservative, whereas mutations in EGFR and ALK tend to be radical. Analysis of Abl1 compound mutations suggests that such mutations are more prevalent than hitherto reported and may be more difficult to counter. This supports the notion that such mutations may provide an escape route for targeted cancer drug resistance. PMID:24376513

Identification of novel mutational drivers reveals oncogene dependencies in multiple myeloma.

PubMed

Walker, Brian A; Mavrommatis, Konstantinos; Wardell, Christopher P; Ashby, T Cody; Bauer, Michael; Davies, Faith E; Rosenthal, Adam; Wang, Hongwei; Qu, Pingping; Hoering, Antje; Samur, Mehmet; Towfic, Fadi; Ortiz, Maria; Flynt, Erin; Yu, Zhinuan; Yang, Zhihong; Rozelle, Dan; Obenauer, John; Trotter, Matthew; Auclair, Daniel; Keats, Jonathan; Bolli, Niccolo; Fulciniti, Mariateresa; Szalat, Raphael; Moreau, Philippe; Durie, Brian; Stewart, A Keith; Goldschmidt, Hartmut; Raab, Marc S; Einsele, Hermann; Sonneveld, Pieter; San Miguel, Jesus; Lonial, Sagar; Jackson, Graham H; Anderson, Kenneth C; Avet-Loiseau, Herve; Munshi, Nikhil; Thakurta, Anjan; Morgan, Gareth J

2018-06-08

Understanding the profile of oncogene and tumor suppressor gene mutations with their interactions and impact on the prognosis of multiple myeloma (MM) can improve the definition of disease subsets and identify pathways important in disease pathobiology. Using integrated genomics of 1,273 newly diagnosed patients with multiple myeloma we identify 63 driver genes, some of which are novel including IDH1 , IDH2 , HUWE1 , KLHL6 , and PTPN11 Oncogene mutations are significantly more clonal than tumor suppressor mutations, indicating they may exert a bigger selective pressure. Patients with more mutations in driver genes are associated with a worse outcome, as are those with identified mechanisms of genomic instability. Oncogenic dependencies were identified between mutations in driver genes, common regions of copy number change, and primary translocation and hyperdiploidy events. These dependencies included associations with t(4;14) and mutations in FGFR3 , DIS3 and PRKD2 ; t(11;14) with mutations in CCND1 and IRF4 ; t(14;16) with mutations in MAF , BRAF , DIS3 and ATM ; and hyperdiploidy with gain 11q, mutations in FAM46C and MYC rearrangements. These associations indicate that the genomic landscape of myeloma is pre-determined by the primary events upon which further dependencies are built, giving rise to a non-random accumulation of genetic hits. Understanding these dependencies may elucidate potential evolutionary patterns and lead to better treatment regimens. Copyright © 2018 American Society of Hematology.

Tumor suppressors Sav/Scrib and oncogene Ras regulate stem cell transformation in adult Drosophila Malpighian Tubules

PubMed Central

Zeng, Xiankun; Singh, Shree Ram; Hou, David; Hou, Steven X.

2012-01-01

An increasing body of evidence suggests that tumors might originate from a few transformed cells that share many properties with normal stem cells. However, it remains unclear how normal stem cells are transformed into cancer stem cells. Here, we demonstrated that mutations causing the loss of tumor suppressor Sav or Scrib or activation of the oncogene Ras transform normal stem cells into cancer stem cells through a multistep process in the adult Drosophila Malpighian Tubules (MTs). In wild-type MTs, each stem cell generates one self-renewing and one differentiating daughter cell. However, in flies with loss-of-function sav or scrib or gain-of-function Ras mutations, both daughter cells grew and behaved like stem cells, leading to the formation of tumors in MTs. Ras functioned downstream of Sav and Scrib in regulating the stem cell transformation. The Ras-transformed stem cells exhibited many of the hallmarks of cancer, such as increased proliferation, reduced cell death, and failure to differentiate. We further demonstrated that several signal transduction pathways (including MEK/MAPK, RhoA, PKA, and TOR) mediate Rasṕ function in the stem cell transformation. Therefore, we have identified a molecular mechanism that regulates stem cell transformation, and this finding may lead to strategies for preventing tumor formation in certain organs. PMID:20432470

Targeted Therapies in NSCLC: Emerging oncogene targets following the success of EGFR

PubMed Central

Berge, Eamon M; Doebele, Robert C

2014-01-01

The diagnostic testing, treatment and prognosis of non-small cell lung cancer (NSCLC) has undergone a paradigm shift since the discovery of sensitizing mutations in the epidermal growth factor receptor (EGFR) gene in a subset of NSCLC patients. Several additional oncogenic mutations, including gene fusions and amplifications have since been discovered, with a number of drugs that target each specific oncogene. This review focuses on oncogenes in NSCLC other than EGFR and their companion ‘targeted therapies’. Particular emphasis is placed on the role of ALK, ROS1, RET, MET, BRAF, and HER2 in NSCLC. PMID:24565585

Small molecule stabilization of the KSR inactive state antagonizes oncogenic Ras signalling

PubMed Central

Dhawan, Neil S.; scopton, Alex P.; Dar, Arvin C.

2016-01-01

Deregulation of the Ras–mitogen activated protein kinase (MAPK) pathway is an early event in many different cancers and a key driver of resistance to targeted therapies1. Sustained signalling through this pathway is caused most often by mutations in K-Ras, which biochemically favours the stabilization of active RAF signalling complexes2. Kinase suppressor of Ras (KSR) is a MAPK scaffold3–5 that is subject to allosteric regulation through dimerization with RAF6,7. Direct targeting of KSR could have important therapeutic implications for cancer; however, testing this hypothesis has been difficult owing to a lack of small-molecule antagonists of KSR function. Guided by KSR mutations that selectively suppress oncogenic, but not wild-type, Ras signalling, we developed a class of compounds that stabilize a previously unrecognized inactive state of KSR. These compounds, exemplified by APS-2-79, modulate KSR-dependent MAPK signalling by antagonizing RAF heterodimerization as well as the conformational changes required for phosphorylation and activation of KSR-bound MEK (mitogen-activated protein kinase kinase). Furthermore, APS-2-79 increased the potency of several MEK inhibitors specifically within Ras-mutant cell lines by antagonizing release of negative feedback signalling, demonstrating the potential of targeting KSR to improve the efficacy of current MAPK inhibitors. These results reveal conformational switching in KSR as a druggable regulator of oncogenic Ras, and further suggest co-targeting of enzymatic and scaffolding activities within Ras–MAPK signalling complexes as a therapeutic strategy for overcoming Ras-driven cancers. PMID:27556948

Mutational landscape of EGFR-, MYC-, and Kras-driven genetically engineered mouse models of lung adenocarcinoma

PubMed Central

McFadden, David G.; Politi, Katerina; Bhutkar, Arjun; Chen, Frances K.; Song, Xiaoling; Pirun, Mono; Santiago, Philip M.; Kim-Kiselak, Caroline; Platt, James T.; Lee, Emily; Hodges, Emily; Rosebrock, Adam P.; Bronson, Roderick T.; Socci, Nicholas D.; Hannon, Gregory J.; Jacks, Tyler; Varmus, Harold

2016-01-01

Genetically engineered mouse models (GEMMs) of cancer are increasingly being used to assess putative driver mutations identified by large-scale sequencing of human cancer genomes. To accurately interpret experiments that introduce additional mutations, an understanding of the somatic genetic profile and evolution of GEMM tumors is necessary. Here, we performed whole-exome sequencing of tumors from three GEMMs of lung adenocarcinoma driven by mutant epidermal growth factor receptor (EGFR), mutant Kirsten rat sarcoma viral oncogene homolog (Kras), or overexpression of MYC proto-oncogene. Tumors from EGFR- and Kras-driven models exhibited, respectively, 0.02 and 0.07 nonsynonymous mutations per megabase, a dramatically lower average mutational frequency than observed in human lung adenocarcinomas. Tumors from models driven by strong cancer drivers (mutant EGFR and Kras) harbored few mutations in known cancer genes, whereas tumors driven by MYC, a weaker initiating oncogene in the murine lung, acquired recurrent clonal oncogenic Kras mutations. In addition, although EGFR- and Kras-driven models both exhibited recurrent whole-chromosome DNA copy number alterations, the specific chromosomes altered by gain or loss were different in each model. These data demonstrate that GEMM tumors exhibit relatively simple somatic genotypes compared with human cancers of a similar type, making these autochthonous model systems useful for additive engineering approaches to assess the potential of novel mutations on tumorigenesis, cancer progression, and drug sensitivity. PMID:27702896

Mutational landscape of EGFR-, MYC-, and Kras-driven genetically engineered mouse models of lung adenocarcinoma.

PubMed

McFadden, David G; Politi, Katerina; Bhutkar, Arjun; Chen, Frances K; Song, Xiaoling; Pirun, Mono; Santiago, Philip M; Kim-Kiselak, Caroline; Platt, James T; Lee, Emily; Hodges, Emily; Rosebrock, Adam P; Bronson, Roderick T; Socci, Nicholas D; Hannon, Gregory J; Jacks, Tyler; Varmus, Harold

2016-10-18

Genetically engineered mouse models (GEMMs) of cancer are increasingly being used to assess putative driver mutations identified by large-scale sequencing of human cancer genomes. To accurately interpret experiments that introduce additional mutations, an understanding of the somatic genetic profile and evolution of GEMM tumors is necessary. Here, we performed whole-exome sequencing of tumors from three GEMMs of lung adenocarcinoma driven by mutant epidermal growth factor receptor (EGFR), mutant Kirsten rat sarcoma viral oncogene homolog (Kras), or overexpression of MYC proto-oncogene. Tumors from EGFR- and Kras-driven models exhibited, respectively, 0.02 and 0.07 nonsynonymous mutations per megabase, a dramatically lower average mutational frequency than observed in human lung adenocarcinomas. Tumors from models driven by strong cancer drivers (mutant EGFR and Kras) harbored few mutations in known cancer genes, whereas tumors driven by MYC, a weaker initiating oncogene in the murine lung, acquired recurrent clonal oncogenic Kras mutations. In addition, although EGFR- and Kras-driven models both exhibited recurrent whole-chromosome DNA copy number alterations, the specific chromosomes altered by gain or loss were different in each model. These data demonstrate that GEMM tumors exhibit relatively simple somatic genotypes compared with human cancers of a similar type, making these autochthonous model systems useful for additive engineering approaches to assess the potential of novel mutations on tumorigenesis, cancer progression, and drug sensitivity.

Profiling of Resistance Patterns & Oncogenic Signaling Pathways in Evaluation of Cancers of the Thorax and Therapeutic Target Identification

DTIC Science & Technology

2010-06-01

mutation si gnature i s prognostic in EGFR wild-type l ung adenocarcinomas and identifies Metastasis associated in colon cancer 1 (MACC1) as an EGFR...T790M mutation (N=7, blue curve) (AUC: area under the curve). Figure 3. EGFR dependency signature is a favorable prognostic factor. EGFR index...developed. T he si gnature w as shown t o b e prognostic regardless of EGFR status. T he results also suggest MACC1 to be a regulator of MET in NSCLC

Mastocytosis: a mutated KIT receptor induced myeloproliferative disorder

PubMed Central

Chatterjee, Anindya; Ghosh, Joydeep; Kapur, Reuben

2015-01-01

Although more than 90% systemic mastocytosis (SM) patients express gain of function mutations in the KIT receptor, recent next generation sequencing has revealed the presence of several additional genetic and epigenetic mutations in a subset of these patients, which confer poor prognosis and inferior overall survival. A clear understanding of how genetic and epigenetic mutations cooperate in regulating the tremendous heterogeneity observed in these patients will be essential for designing effective treatment strategies for this complex disease. In this review, we describe the clinical heterogeneity observed in patients with mastocytosis, the nature of relatively novel mutations identified in these patients, therapeutic strategies to target molecules downstream from activating KIT receptor and finally we speculate on potential novel strategies to interfere with the function of not only the oncogenic KIT receptor but also epigenetic mutations seen in these patients. PMID:26158763

Response of Head and Neck Squamous Cell Carcinoma Cells Carrying PIK3CA Mutations to Select Targeted Therapies

PubMed Central

Wirtz, Eric D; Hoshino, Daisuke; Maldonado, Anthony T; Tyson, Darren R; Weaver, Alissa M

2015-01-01

Importance The PIK3CA mutation is one of the most common mutations in Head and Neck Squamous Cell Carcinoma (HNSCC). Through this research we attempt to elicit the role of oncogene dependence and effects of targeted therapy on this PIK3CA mutation. Objectives 1) To determine the role of oncogene dependence on one of the more common and targetable oncogenes in HNSCC – PIK3CA; 2) To evaluate the consequence of this oncogene on the effectiveness of newly developed targeted therapies. Study Design In vitro study. Setting Academic research laboratory. Participants Cell culture based study assessing the viability of PIK3CA mutated head and neck cell lines when treated with targeted therapy. Exposures PIK3CA mutated head and neck cell lines were treated with 17-AAG, GDC-0941, trametinib, and BEZ-235. Main Outcome and Measures Assessment of cell viability of HNSCC cell lines characterized for PIK3CA mutations or SCC25 cells engineered to express the PIK3CA hotspot mutations E545K or H1047R Results Surprisingly, in engineered cell lines, the hotspot E545K and H1047R mutations conferred decreased, rather than increased, sensitivity as measured by IC50 when treated with the respective HSP90, PI3K, and MEK inhibitors, 17-AAG, GDC-0941, and trametinib, compared to the SCC25 control cell lines. When treated with BEZ-235, H1047R-expressing cell lines showed increased sensitivity to inhibition compared to control while those expressing E545K showed slightly increased sensitivity of unclear significance. Conclusions and Relevance 1) The PIK3CA mutations within our engineered cell model did not lead to enhanced oncogene-dependent cell death when treated with direct inhibition of the PI3K enzyme yet did show increased sensitivity compared to control with dual PI3K/mTOR inhibition. 2) Oncogene addiction to PIK3CA hot spot mutations, if it occurs, is likely to evolve in vivo molecular changes that remain to be identified. Additional study is required to develop new model systems and approaches to determine the role of targeted therapy in the treatment of PI3K-overactive HNSCC tumors. PMID:25855885

Loss of Oncogenic Notch1 with Resistance to a PI3K Inhibitor in T Cell Leukaemia

PubMed Central

Dail, Monique; Wong, Jason; Lawrence, Jessica; O’Connor, Daniel; Nakitandwe, Joy; Chen, Shann-Ching; Xu, Jin; Lee, Leslie B; Akagi, Keiko; Li, Qing; Aster, Jon C.; Pear, Warren S.; Downing, James R; Sampath, Deepak; Shannon, Kevin

2014-01-01

Mutations that deregulate Notch1 and Ras/PI3 kinase/Akt signalling are prevalent in T lineage acute lymphoblastic leukaemia (T-ALL), and often coexist. The PI3 kinase inhibitor GDC-0941 was active against primary T-ALLs from wild-type and KrasG12D mice and addition of the MEK inhibitor PD0325901 increased efficacy. Mice invariably relapsed after treatment with drug resistant clones, most of which unexpectedly had reduced levels of activated Notch1 protein, down-regulated many Notch1 target genes, and exhibited cross-resistance to γ secretase inhibitors. Multiple resistant primary T-ALLs that emerged in vivo did not contain somatic Notch1 mutations present in the parental leukaemia. Importantly, resistant clones up-regulated PI3K signalling. Consistent with these data, inhibiting Notch1 activated the PI3K pathway, providing a likely mechanism for selection against oncogenic Notch1 signalling. These studies validate PI3K as a therapeutic target in T-ALL and raise the unexpected possibility that dual inhibition of PI3K and Notch1 signalling could facilitate drug resistance in T-ALL. PMID:25043004

Modulation of oncogenic transcription factors by bioactive natural products in breast cancer.

PubMed

Hasanpourghadi, Mohadeseh; Pandurangan, Ashok Kumar; Mustafa, Mohd Rais

2018-02-01

Carcinogenesis, a multi-step phenomenon, characterized by alterations at genetic level and affecting the main intracellular pathways controlling cell growth and development. There are growing number of evidences linking oncogenes to the induction of malignancies, especially breast cancer. Modulations of oncogenes lead to gain-of-function signals in the cells and contribute to the tumorigenic phenotype. These signals yield a large number of proteins that cause cell growth and inhibit apoptosis. Transcription factors such as STAT, p53, NF-κB, c-JUN and FOXM1, are proteins that are conserved among species, accumulate in the nucleus, bind to DNA and regulate the specific genes targets. Oncogenic transcription factors resulting from the mutation or overexpression following aberrant gene expression relay the signals in the nucleus and disrupt the transcription pattern. Activation of oncogenic transcription factors is associated with control of cell cycle, apoptosis, migration and cell differentiation. Among different cancer types, breast cancer is one of top ten cancers worldwide. There are different subtypes of breast cancer cell-lines such as non-aggressive MCF-7 and aggressive and metastatic MDA-MB-231 cells, which are identified with distinct molecular profile and different levels of oncogenic transcription factor. For instance, MDA-MB-231 carries mutated and overexpressed p53 with its abnormal, uncontrolled downstream signalling pathway that account for resistance to several anticancer drugs compared to MCF-7 cells with wild-type p53. Appropriate enough, inhibition of oncogenic transcription factors has become a potential target in discovery and development of anti-tumour drugs against breast cancer. Plants produce diverse amount of organic metabolites. Universally, these metabolites with biological activities are known as "natural products". The chemical structure and function of natural products have been studied since 1850s. Investigating these properties leaded to recognition of their molecular effects as anticancer drugs. Numerous natural products extracted from plants, fruits, mushrooms and mycelia, show potential inhibitory effects against several oncogenic transcription factors in breast cancer. Natural compounds that target oncogenic transcription factors have increased the number of candidate therapeutic agents. This review summarizes the current findings of natural products in targeting specific oncogenic transcription factors in breast cancer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Regulation of Stat5 by FAK and PAK1 in Oncogenic FLT3- and KIT-Driven Leukemogenesis.

PubMed

Chatterjee, Anindya; Ghosh, Joydeep; Ramdas, Baskar; Mali, Raghuveer Singh; Martin, Holly; Kobayashi, Michihiro; Vemula, Sasidhar; Canela, Victor H; Waskow, Emily R; Visconte, Valeria; Tiu, Ramon V; Smith, Catherine C; Shah, Neil; Bunting, Kevin D; Boswell, H Scott; Liu, Yan; Chan, Rebecca J; Kapur, Reuben

2014-11-20

Oncogenic mutations of FLT3 and KIT receptors are associated with poor survival in patients with acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPNs), and currently available drugs are largely ineffective. Although Stat5 has been implicated in regulating several myeloid and lymphoid malignancies, how precisely Stat5 regulates leukemogenesis, including its nuclear translocation to induce gene transcription, is poorly understood. In leukemic cells, we show constitutive activation of focal adhesion kinase (FAK) whose inhibition represses leukemogenesis. Downstream of FAK, activation of Rac1 is regulated by RacGEF Tiam1, whose inhibition prolongs the survival of leukemic mice. Inhibition of the Rac1 effector PAK1 prolongs the survival of leukemic mice in part by inhibiting the nuclear translocation of Stat5. These results reveal a leukemic pathway involving FAK/Tiam1/Rac1/PAK1 and demonstrate an essential role for these signaling molecules in regulating the nuclear translocation of Stat5 in leukemogenesis. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Oncogenic roles of PRL-3 in FLT3-ITD induced acute myeloid leukaemia

PubMed Central

Park, Jung Eun; Yuen, Hiu Fung; Zhou, Jian Biao; Al-aidaroos, Abdul Qader O; Guo, Ke; Valk, Peter J; Zhang, Shu Dong; Chng, Wee Joo; Hong, Cheng William; Mills, Ken; Zeng, Qi

2013-01-01

FLT3-ITD mutations are prevalent mutations in acute myeloid leukaemia (AML). PRL-3, a metastasis-associated phosphatase, is a downstream target of FLT3-ITD. This study investigates the regulation and function of PRL-3 in leukaemia cell lines and AML patients associated with FLT3-ITD mutations. PRL-3 expression is upregulated by the FLT3-STAT5 signalling pathway in leukaemia cells, leading an activation of AP-1 transcription factors via ERK and JNK pathways. PRL-3-depleted AML cells showed a significant decrease in cell growth. Clinically, high PRL-3 mRNA expression was associated with FLT3-ITD mutations in four independent AML datasets with 1158 patients. Multivariable Cox-regression analysis on our Cohort 1 with 221 patients identified PRL-3 as a novel prognostic marker independent of other clinical parameters. Kaplan–Meier analysis showed high PRL-3 mRNA expression was significantly associated with poorer survival among 491 patients with normal karyotype. Targeting PRL-3 reversed the oncogenic effects in FLT3-ITD AML models in vitro and in vivo. Herein, we suggest that PRL-3 could serve as a prognostic marker to predict poorer survival and as a promising novel therapeutic target for AML patients. PMID:23929599

Molecular concept in human oral cancer.

PubMed

Krishna, Akhilesh; Singh, Shraddha; Kumar, Vijay; Pal, U S

2015-01-01

The incidence of oral cancer remains high in both Asian and Western countries. Several risk factors associated with development of oral cancer are now well-known, including tobacco chewing, smoking, and alcohol consumption. Cancerous risk factors may cause many genetic events through chromosomal alteration or mutations in genetic material and lead to progression and development of oral cancer through histological progress, carcinogenesis. Oral squamous carcinogenesis is a multistep process in which multiple genetic events occur that alter the normal functions of proto-oncogenes/oncogenes and tumor suppressor genes. Furthermore, these gene alterations can deregulate the normal activity such as increase in the production of growth factors (transforming growth factor-α [TGF-α], TGF-β, platelet-derived growth factor, etc.) or numbers of cell surface receptors (epidermal growth factor receptor, G-protein-coupled receptor, etc.), enhanced intracellular messenger signaling and mutated production of transcription factors (ras gene family, c-myc gene) which results disturb to tightly regulated signaling pathways of normal cell. Several oncogenes and tumor suppressor genes have been implicated in oral cancer especially cyclin family, ras, PRAD-1, cyclin-dependent kinase inhibitors, p53 and RB1. Viral infections, particularly with oncogenic human papilloma virus subtype (16 and 18) and Epstein-Barr virus have tumorigenic effect on oral epithelia. Worldwide, this is an urgent need to initiate oral cancer research programs at molecular and genetic level which investigates the causes of genetic and molecular defect, responsible for malignancy. This approach may lead to development of target dependent tumor-specific drugs and appropriate gene therapy.

Molecular concept in human oral cancer

PubMed Central

Krishna, Akhilesh; Singh, Shraddha; Kumar, Vijay; Pal, U. S.

2015-01-01

The incidence of oral cancer remains high in both Asian and Western countries. Several risk factors associated with development of oral cancer are now well-known, including tobacco chewing, smoking, and alcohol consumption. Cancerous risk factors may cause many genetic events through chromosomal alteration or mutations in genetic material and lead to progression and development of oral cancer through histological progress, carcinogenesis. Oral squamous carcinogenesis is a multistep process in which multiple genetic events occur that alter the normal functions of proto-oncogenes/oncogenes and tumor suppressor genes. Furthermore, these gene alterations can deregulate the normal activity such as increase in the production of growth factors (transforming growth factor-α [TGF-α], TGF-β, platelet-derived growth factor, etc.) or numbers of cell surface receptors (epidermal growth factor receptor, G-protein-coupled receptor, etc.), enhanced intracellular messenger signaling and mutated production of transcription factors (ras gene family, c-myc gene) which results disturb to tightly regulated signaling pathways of normal cell. Several oncogenes and tumor suppressor genes have been implicated in oral cancer especially cyclin family, ras, PRAD-1, cyclin-dependent kinase inhibitors, p53 and RB1. Viral infections, particularly with oncogenic human papilloma virus subtype (16 and 18) and Epstein-Barr virus have tumorigenic effect on oral epithelia. Worldwide, this is an urgent need to initiate oral cancer research programs at molecular and genetic level which investigates the causes of genetic and molecular defect, responsible for malignancy. This approach may lead to development of target dependent tumor-specific drugs and appropriate gene therapy. PMID:26668446

Advances in human genetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, H.; Hirschhorn, K.

1993-01-01

This book has five chapters covering peroxisomal diseases, X-linked immunodeficiencies, genetic mutations affecting human lipoproteins and their receptors and enzymes, genetic aspects of cancer, and Gaucher disease. The chapter on peroxisomes covers their discovery, structure, functions, disorders, etc. The chapter on X-linked immunodeficiencies discusses such diseases as agammaglobulinemia, severe combined immunodeficiency, Wiskott-Aldrich syndrome, animal models, linkage analysis, etc. Apolipoprotein formation, synthesis, gene regulation, proteins, etc. are the main focus of chapter 3. The chapter on cancer covers such topics as oncogene mapping and the molecular characterization of some recessive oncogenes. Gaucher disease is covered from its diagnosis, classification, and prevention,more » to its organ system involvement and molecular biology.« less

RUNX1 promotes cell growth in human T-cell acute lymphoblastic leukemia by transcriptional regulation of key target genes.

PubMed

Jenkins, Catherine E; Gusscott, Samuel; Wong, Rachel J; Shevchuk, Olena O; Rana, Gurneet; Giambra, Vincenzo; Tyshchenko, Kateryna; Islam, Rashedul; Hirst, Martin; Weng, Andrew P

2018-05-04

RUNX1 is frequently mutated in T-cell acute lymphoblastic leukemia (T-ALL). The spectrum of RUNX1 mutations has led to the notion that it acts as a tumor suppressor in this context; however, other studies have placed RUNX1 along with transcription factors TAL1 and NOTCH1 as core drivers of an oncogenic transcriptional program. To reconcile these divergent roles, we knocked down RUNX1 in human T-ALL cell lines and deleted Runx1 or Cbfb in primary mouse T-cell leukemias. RUNX1 depletion consistently resulted in reduced cell proliferation and increased apoptosis. RUNX1 upregulated variable sets of target genes in each cell line, but consistently included a core set of oncogenic effectors including IGF1R and NRAS. Our results support the conclusion that RUNX1 has a net positive effect on cell growth in the context of established T-ALL. Copyright © 2018. Published by Elsevier Inc.

KRAS oncogene in non-small cell lung cancer: clinical perspectives on the treatment of an old target.

PubMed

Román, Marta; Baraibar, Iosune; López, Inés; Nadal, Ernest; Rolfo, Christian; Vicent, Silvestre; Gil-Bazo, Ignacio

2018-02-19

Lung neoplasms are the leading cause of death by cancer worldwide. Non-small cell lung cancer (NSCLC) constitutes more than 80% of all lung malignancies and the majority of patients present advanced disease at onset. However, in the last decade, multiple oncogenic driver alterations have been discovered and each of them represents a potential therapeutic target. Although KRAS mutations are the most frequently oncogene aberrations in lung adenocarcinoma patients, effective therapies targeting KRAS have yet to be developed. Moreover, the role of KRAS oncogene in NSCLC remains unclear and its predictive and prognostic impact remains controversial. The study of the underlying biology of KRAS in NSCLC patients could help to determine potential candidates to evaluate novel targeted agents and combinations that may allow a tailored treatment for these patients. The aim of this review is to update the current knowledge about KRAS-mutated lung adenocarcinoma, including a historical overview, the biology of the molecular pathways involved, the clinical relevance of KRAS mutations as a prognostic and predictive marker and the potential therapeutic approaches for a personalized treatment of KRAS-mutated NSCLC patients.

Gain-of-function mutant p53 but not p53 deletion promotes head and neck cancer progression in response to oncogenic K-ras

PubMed Central

Acin, Sergio; Li, Zhongyou; Mejia, Olga; Roop, Dennis R; El-Naggar, Adel K; Caulin, Carlos

2015-01-01

Mutations in p53 occur in over 50% of the human head and neck squamous cell carcinomas (SCCHN). The majority of these mutations result in the expression of mutant forms of p53, rather than deletions in the p53 gene. Some p53 mutants are associated with poor prognosis in SCCHN patients. However, the molecular mechanisms that determine the poor outcome of cancers carrying p53 mutations are unknown. Here, we generated a mouse model for SCCHN and found that activation of the endogenous p53 gain-of-function mutation p53R172H, but not deletion of p53, cooperates with oncogenic K-ras during SCCHN initiation, accelerates oral tumour growth, and promotes progression to carcinoma. Mechanistically, expression profiling of the tumours that developed in these mice and studies using cell lines derived from these tumours determined that mutant p53 induces the expression of genes involved in mitosis, including cyclin B1 and cyclin A, and accelerates entry in mitosis. Additionally, we discovered that this oncogenic function of mutant p53 was dependent on K-ras because the expression of cyclin B1 and cyclin A decreased, and entry in mitosis was delayed, after suppressing K-ras expression in oral tumour cells that express p53R172H. The presence of double-strand breaks in the tumours suggests that oncogene-dependent DNA damage resulting from K-ras activation promotes the oncogenic function of mutant p53. Accordingly, DNA damage induced by doxorubicin also induced increased expression of cyclin B1 and cyclin A in cells that express p53R172H. These findings represent strong in vivo evidence for an oncogenic function of endogenous p53 gain-of-function mutations in SCCHN and provide a mechanistic explanation for the genetic interaction between oncogenic K-ras and mutant p53. PMID:21952947

NF-κB in Hematological Malignancies

PubMed Central

Imbert, Véronique; Peyron, Jean-François

2017-01-01

NF-κB (Nuclear Factor Κ-light-chain-enhancer of activated B cells) transcription factors are critical regulators of immunity, stress response, apoptosis, and differentiation. Molecular defects promoting the constitutive activation of canonical and non-canonical NF-κB signaling pathways contribute to many diseases, including cancer, diabetes, chronic inflammation, and autoimmunity. In the present review, we focus our attention on the mechanisms of NF-κB deregulation in hematological malignancies. Key positive regulators of NF-κB signaling can act as oncogenes that are often prone to chromosomal translocation, amplifications, or activating mutations. Negative regulators of NF-κB have tumor suppressor functions, and are frequently inactivated either by genomic deletions or point mutations. NF-κB activation in tumoral cells is also driven by the microenvironment or chronic signaling that does not rely on genetic alterations. PMID:28561798

Oncogenic collaboration of the cyclin D1 (PRAD1, bcl-1) gene with a mutated p53 and an activated ras oncogene in neoplastic transformation.

PubMed

Uchimaru, K; Endo, K; Fujinuma, H; Zukerberg, L; Arnold, A; Motokura, T

1996-05-01

Cyclin D1 is one of the key regulators in G1 progression in the cell cycle and is also a candidate oncogene (termed PRAD1 or bcl-1) in several types of human tumors. We report a collaboration of the cyclin D1 gene with ras and a mutated form of p53 (p53-mt) in neoplastic transformation. Transfection of cyclin D1 alone or in combination with ras or with p53-mt was not sufficient for focus formation of rat embryonic fibroblasts. However, focus formation induced by co-transfection of ras and p53-mt was enhanced in the presence of the cyclin D1-expression plasmid. Co-transfection of ras- and p53-mt-transformants with the cyclin D1-expression plasmid resulted in reduced serum dependency in vitro. Furthermore, the transformants expressing exogenous cyclin D1 grew faster than those without the cyclin D1 plasmid when injected into nude mice. These observations strengthen the significance of cyclin D1 overexpression through gene rearrangement or gene amplification observed in human tumors as a step in multistep oncogenesis; deregulated expression of cyclin D1 may reduce the requirement for growth factors and may stimulate in vivo growth.

Suppression of intestinal tumorigenesis in Apc mutant mice upon Musashi-1 deletion.

PubMed

Wolfe, Andy R; Ernlund, Amanda; McGuinness, William; Lehmann, Carl; Carl, Kaitlyn; Balmaceda, Nicole; Neufeld, Kristi L

2017-02-15

Therapeutic strategies based on a specific oncogenic target are better justified when elimination of that particular oncogene reduces tumorigenesis in a model organism. One such oncogene, Musashi-1 ( Msi-1 ), regulates translation of target mRNAs and is implicated in promoting tumorigenesis in the colon and other tissues. Msi-1 targets include the tumor suppressor adenomatous polyposis coli ( Apc ), a Wnt pathway antagonist lost in ∼80% of all colorectal cancers. Cell culture experiments have established that Msi-1 is a Wnt target, thus positioning Msi-1 and Apc as mutual antagonists in a mutually repressive feedback loop. Here, we report that intestines from mice lacking Msi-1 display aberrant Apc and Msi-1 mutually repressive feedback, reduced Wnt and Notch signaling, decreased proliferation, and changes in stem cell populations, features predicted to suppress tumorigenesis. Indeed, mice with germline Apc mutations ( Apc Min ) or with the Apc 1322T truncation mutation have a dramatic reduction in intestinal polyp number when Msi-1 is deleted. Taken together, these results provide genetic evidence that Msi-1 contributes to intestinal tumorigenesis driven by Apc loss, and validate the pursuit of Msi-1 inhibitors as chemo-prevention agents to reduce tumor burden. © 2017. Published by The Company of Biologists Ltd.

The Effect of Coexistence of a Pair of Mutated Oncogenes on the Survival Rate of Invasive Breast Carcinoma Patients

NASA Astrophysics Data System (ADS)

Nair, D. R.

2017-12-01

The purpose of this project was to determine the effect of two mutated oncogenes on the survival rate from invasive breast carcinoma when in comparison to the mutation of a single oncogene on the survival rate. An oncogene is defined as a gene, that when mutated, can lead to cancer. The two oncogenes used in this project were human epidermal growth factor receptor 2 (HER2) and c-myc (MYC). HER2 and MYC are both oncogenes that contribute to the formation of cancer. HER2 proteins are receptors on breast cells, and when the HER2 gene is mutated, there is an overexpression of HER2 protein on the breast cell. This makes the breast cells proliferate uncontrollably. MYC is a gene that codes for a transcription factor that plays a role in cell cycle progression. The overexpression of MYC also leads to the proliferation of cells. I hypothesized that if there is a mutation in both the MYC and HER2 genes, then the survival rate of invasive breast carcinoma patients will be lower compared to patients with the mutations of only MYC or HER2. To test this hypothesis, we conducted individual gene searches in CBioPortal for HER2 in the datasets from the studies titled TCGA Nature 2012, TCGA Cell 2015, and TCGA Provisional. We conducted individual gene searches in CBioPortal for MYC in the same datasets. The survival rate data was then exported and analyzed for patients with mutations of either HER2 or MYC and with mutations of both genes. To determine the cases that had both HER2 and MYC mutations, we found the overlapping cases in both HER2 and MYC groups for all three datasets. We calculated the median of the survival data for cases where either HER2 or MYC was mutated and cases where both MYC and HER2 were mutated. From the first dataset, the median of MYC data was 95.53, HER2 data was 95.83, and both HER2 and MYC data was 91.24. In the second dataset, the median of MYC data was 92.17 , HER2 data was 93.5, and both HER2 and MYC data was 87.95 . In the third dataset, the median of MYC data was 92.18, HER2 data was 94.22, and both HER2 and MYC data was 89.45. The median survival rates all showed that cases with mutations in both genes had a lower survival rate than those with single mutations. My hypothesis was supported. Some sources of error are the fewer number of cases in the TCGA Nature 2012 dataset, making this data statistically insignificant.

A mutant p53/let-7i-axis-regulated gene network drives cell migration, invasion and metastasis

PubMed Central

Subramanian, M; Francis, P; Bilke, S; Li, XL; Hara, T; Lu, X; Jones, MF; Walker, RL; Zhu, Y; Pineda, M; Lee, C; Varanasi, L; Yang, Y; Martinez, LA; Luo, J; Ambs, S; Sharma, S; Wakefield, LM; Meltzer, PS; Lal, A

2015-01-01

Most p53 mutations in human cancers are missense mutations resulting in a full-length mutant p53 protein. Besides losing tumor suppressor activity, some hotspot p53 mutants gain oncogenic functions. This effect is mediated in part, through gene expression changes due to inhibition of p63 and p73 by mutant p53 at their target gene promoters. Here, we report that the tumor suppressor microRNA let-7i is downregulated by mutant p53 in multiple cell lines expressing endogenous mutant p53. In breast cancer patients, significantly decreased let-7i levels were associated with missense mutations in p53. Chromatin immunoprecipitation and promoter luciferase assays established let-7i as a transcriptional target of mutant p53 through p63. Introduction of let-7i to mutant p53 cells significantly inhibited migration, invasion and metastasis by repressing a network of oncogenes including E2F5, LIN28B, MYC and NRAS. Our findings demonstrate that repression of let-7i expression by mutant p53 has a key role in enhancing migration, invasion and metastasis. PMID:24662829

Advances in the translational genomics of neuroblastoma

PubMed Central

Bosse, Kristopher R.; Maris, John M.

2015-01-01

Neuroblastoma is an embryonal malignancy that commonly affects young children and is remarkably heterogenous in its malignant potential. Recently, the genetic basis of neuroblastoma has come into focus, which has catalyzed not only a more comprehensive understanding of neuroblastoma tumorigenesis, but has also revealed novel oncogenic vulnerabilities that are being leveraged therapeutically. Neuroblastoma is a model pediatric solid tumor in its use of recurrent genomic alterations, such as high-level MYCN amplification, for risk stratification. Given the relative paucity of recurrent activating somatic point mutations or gene fusions in primary neuroblastoma tumors studied at initial diagnosis, innovative treatment approaches beyond small molecules targeting mutated or dysregulated kinases will be required moving forward to achieve noticeable improvements in overall patient survival. However, the clonally acquired, oncogenic aberrations in relapsed neuroblastomas are currently being defined and may offer an opportunity to improve patient outcomes with molecularly targeted therapy directed towards aberrantly regulated pathways in relapsed disease. This review will summarize the current state of knowledge of neuroblastoma genetics and genomics, highlighting the improved prognostication and potential therapeutic opportunities that have arisen from recent advances in understanding germline predisposition, recurrent segmental chromosomal alterations, somatic point mutations and translocations, and clonal evolution in relapsed neuroblastoma. PMID:26539795

Determination of synthetic lethal interactions in KRAS oncogene-dependent cancer cells reveals novel therapeutic targeting strategies

PubMed Central

Steckel, Michael; Molina-Arcas, Miriam; Weigelt, Britta; Marani, Michaela; Warne, Patricia H; Kuznetsov, Hanna; Kelly, Gavin; Saunders, Becky; Howell, Michael; Downward, Julian; Hancock, David C

2012-01-01

Oncogenic mutations in RAS genes are very common in human cancer, resulting in cells with well-characterized selective advantages, but also less well-understood vulnerabilities. We have carried out a large-scale loss-of-function screen to identify genes that are required by KRAS-transformed colon cancer cells, but not by derivatives lacking this oncogene. Top-scoring genes were then tested in a larger panel of KRAS mutant and wild-type cancer cells. Cancer cells expressing oncogenic KRAS were found to be highly dependent on the transcription factor GATA2 and the DNA replication initiation regulator CDC6. Extending this analysis using a collection of drugs with known targets, we found that cancer cells with mutant KRAS showed selective addiction to proteasome function, as well as synthetic lethality with topoisomerase inhibition. Combination targeting of these functions caused improved killing of KRAS mutant cells relative to wild-type cells. These observations suggest novel targets and new ways of combining existing therapies for optimal effect in RAS mutant cancers, which are traditionally seen as being highly refractory to therapy. PMID:22613949

Multiplex Detection of KRAS Mutations Using Passive Droplet Fusion.

PubMed

Pekin, Deniz; Taly, Valerie

2017-01-01

We describe a droplet microfluidics method to screen for multiple mutations of a same oncogene in a single experiment using passive droplet fusion. Genomic DNA from H1573 cell-line was screened for the presence of the six common mutations of the KRAS oncogene as well as wild-type sequences with a detection efficiency of 98 %. Furthermore, the mutant allelic fraction of the cell-line was also assessed correctly showing that the technique is quantitative.

Comprehensive profiling and quantitation of oncogenic mutations in non small-cell lung carcinoma using single molecule amplification and re-sequencing technology

PubMed Central

Jiang, Hong; Wang, Limin; Xu, Rujun; Shi, Yanbin; Zhang, Jianguang; Xu, Mengnan; Cram, David S.; Ma, Shenglin

2016-01-01

Activating and resistance mutations in the tyrosine kinase domain of several oncogenes are frequently associated with non-small cell lung carcinoma (NSCLC). In this study we assessed the frequency, type and abundance of EGFR, KRAS, BRAF, TP53 and ALK mutations in tumour specimens from 184 patients with early and late stage disease using single molecule amplification and re-sequencing technology (SMART). Based on modelling of EGFR mutations, the detection sensitivity of the SMART assay was at least 0.1%. Benchmarking EGFR mutation detection against the gold standard ARMS-PCR assay, SMART assay had a sensitivity and specificity of 98.7% and 99.0%. Amongst the 184 samples, EGFR mutations were the most prevalent (59.9%), followed by KRAS (16.9%), TP53 (12.7%), EML4-ALK fusions (6.3%) and BRAF (4.2%) mutations. The abundance and types of mutations in tumour specimens were extremely heterogeneous, involving either monoclonal (51.6%) or polyclonal (12.6%) mutation events. At the clinical level, although the spectrum of tumour mutation(s) was unique to each patient, the overall patterns in early or advanced stage disease were relatively similar. Based on these findings, we propose that personalized profiling and quantitation of clinically significant oncogenic mutations will allow better classification of patients according to tumour characteristics and provide clinicians with important ancillary information for treatment decision-making. PMID:27409166

Comprehensive profiling and quantitation of oncogenic mutations in non small-cell lung carcinoma using single molecule amplification and re-sequencing technology.

PubMed

Zhang, Shirong; Xia, Bing; Jiang, Hong; Wang, Limin; Xu, Rujun; Shi, Yanbin; Zhang, Jianguang; Xu, Mengnan; Cram, David S; Ma, Shenglin

2016-08-02

Activating and resistance mutations in the tyrosine kinase domain of several oncogenes are frequently associated with non-small cell lung carcinoma (NSCLC). In this study we assessed the frequency, type and abundance of EGFR, KRAS, BRAF, TP53 and ALK mutations in tumour specimens from 184 patients with early and late stage disease using single molecule amplification and re-sequencing technology (SMART). Based on modelling of EGFR mutations, the detection sensitivity of the SMART assay was at least 0.1%. Benchmarking EGFR mutation detection against the gold standard ARMS-PCR assay, SMART assay had a sensitivity and specificity of 98.7% and 99.0%. Amongst the 184 samples, EGFR mutations were the most prevalent (59.9%), followed by KRAS (16.9%), TP53 (12.7%), EML4-ALK fusions (6.3%) and BRAF (4.2%) mutations. The abundance and types of mutations in tumour specimens were extremely heterogeneous, involving either monoclonal (51.6%) or polyclonal (12.6%) mutation events. At the clinical level, although the spectrum of tumour mutation(s) was unique to each patient, the overall patterns in early or advanced stage disease were relatively similar. Based on these findings, we propose that personalized profiling and quantitation of clinically significant oncogenic mutations will allow better classification of patients according to tumour characteristics and provide clinicians with important ancillary information for treatment decision-making.

Infrequent detectable somatic mutations of the RET and glial cell line-derived neurotrophic factor (GDNF) genes in human pituitary adenomas.

PubMed

Yoshimoto, K; Tanaka, C; Moritani, M; Shimizu, E; Yamaoka, T; Yamada, S; Sano, T; Itakura, M

1999-02-01

RET is a receptor tyrosine kinase expressed in neuroendocrine cells and tumors. RET is activated by a ligand complex comprising glial cell line-derived neurotrophic factor (GDNF) and GDNF receptor-alpha (GDNFR-alpha). Activating mutations of the RET proto-oncogene were found in multiple endocrine neoplasia (MEN) 2 and in sporadic medullary thyroid carcinoma and pheochromocytoma of neuroendocrine origin. Mutations of the RET proto-oncogene and the glial cell line-derived neurotrophic factor (GDNF) gene were examined in human pituitary tumors. No mutations of the RET proto-oncogene including the cysteine-rich region or codon 768 and 918 in the tyrosine kinase domain were detected in 172 human pituitary adenomas either by polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) or by PCR-restriction fragment length polymorphism (RFLP). Further, somatic mutations of the GDNF gene in 33 human pituitary adenomas were not detected by PCR-SSCP. One polymorphism of the GDNF gene at codon 145 of TGC or TGT was observed in a prolactinoma. The RET proto-oncogene message was detected in a normal human pituitary gland or 4 of 4 human pituitary adenomas with reverse transcription (RT)-PCR, and in rodent pituitary tumor cell lines with Western blotting. The expression of GDNF gene was detected in 1 of 4 human somatotroph adenomas, 1 of 2 corticotroph adenomas, and 2 of 6 rodent pituitary tumor cell lines with RT-PCR. Based on these, it is concluded that somatic mutations of the RET proto-oncogene or the GDNF gene do not appear to play a major role in the pituitary tumorigenesis in examined tumors.

Engineering and Functional Characterization of Fusion Genes Identifies Novel Oncogenic Drivers of Cancer.

PubMed

Lu, Hengyu; Villafane, Nicole; Dogruluk, Turgut; Grzeskowiak, Caitlin L; Kong, Kathleen; Tsang, Yiu Huen; Zagorodna, Oksana; Pantazi, Angeliki; Yang, Lixing; Neill, Nicholas J; Kim, Young Won; Creighton, Chad J; Verhaak, Roel G; Mills, Gordon B; Park, Peter J; Kucherlapati, Raju; Scott, Kenneth L

2017-07-01

Oncogenic gene fusions drive many human cancers, but tools to more quickly unravel their functional contributions are needed. Here we describe methodology permitting fusion gene construction for functional evaluation. Using this strategy, we engineered the known fusion oncogenes, BCR-ABL1, EML4-ALK , and ETV6-NTRK3, as well as 20 previously uncharacterized fusion genes identified in The Cancer Genome Atlas datasets. In addition to confirming oncogenic activity of the known fusion oncogenes engineered by our construction strategy, we validated five novel fusion genes involving MET, NTRK2 , and BRAF kinases that exhibited potent transforming activity and conferred sensitivity to FDA-approved kinase inhibitors. Our fusion construction strategy also enabled domain-function studies of BRAF fusion genes. Our results confirmed other reports that the transforming activity of BRAF fusions results from truncation-mediated loss of inhibitory domains within the N-terminus of the BRAF protein. BRAF mutations residing within this inhibitory region may provide a means for BRAF activation in cancer, therefore we leveraged the modular design of our fusion gene construction methodology to screen N-terminal domain mutations discovered in tumors that are wild-type at the BRAF mutation hotspot, V600. We identified an oncogenic mutation, F247L, whose expression robustly activated the MAPK pathway and sensitized cells to BRAF and MEK inhibitors. When applied broadly, these tools will facilitate rapid fusion gene construction for subsequent functional characterization and translation into personalized treatment strategies. Cancer Res; 77(13); 3502-12. ©2017 AACR . ©2017 American Association for Cancer Research.

Splicing-factor alterations in cancers

PubMed Central

Anczuków, Olga; Krainer, Adrian R.

2016-01-01

Tumor-associated alterations in RNA splicing result either from mutations in splicing-regulatory elements or changes in components of the splicing machinery. This review summarizes our current understanding of the role of splicing-factor alterations in human cancers. We describe splicing-factor alterations detected in human tumors and the resulting changes in splicing, highlighting cell-type-specific similarities and differences. We review the mechanisms of splicing-factor regulation in normal and cancer cells. Finally, we summarize recent efforts to develop novel cancer therapies, based on targeting either the oncogenic splicing events or their upstream splicing regulators. PMID:27530828

Y Chromosome Regulation of Autism Susceptibility Genes

DTIC Science & Technology

2009-06-01

with human -like spontaneous mutation. Neuroreport, 2008. 19(7): p. 739-43. 60. Lin, Y.M., et al., Association analysis of monoamine oxidase A gene and...susceptibility genes, including the monoamine oxidase A (MOAA), mediator complex subunit 12 (MED12), homeobox B1 (HOXB1) gastrin-releasing peptide...autism susceptibility genes, the RET proto- oncogene and monoamine oxidase A (MAOA) gene for detail studies. MAOA deaminates monoamines and is involved

INDUCTION OF DNA ADDUCTS, TUMORS, AND KI-RAS ONCOGENE MUTATIONS IN STRAIN A/J MOUSE LUNG BY IP. ADMINISTRATION OF DIBENZ[A,H]ANTHRACENE

EPA Science Inventory

Induction of DNA adducts, tumors, and Ki-ras oncogene mutations in strain AlJ mouse lung by ip. administration of dibenz[a,h]anthracene

Previous studies of polycyclic aromatic hydrocarbon (P AH) induced lung tumors in the strain NJ mouse model system have demonstrated qua...

Signal Transduction in Cancer

PubMed Central

Sever, Richard; Brugge, Joan S.

2015-01-01

SUMMARY Cancer is driven by genetic and epigenetic alterations that allow cells to overproliferate and escape mechanisms that normally control their survival and migration. Many of these alterations map to signaling pathways that control cell growth and division, cell death, cell fate, and cell motility, and can be placed in the context of distortions of wider signaling networks that fuel cancer progression, such as changes in the tumor microenvironment, angiogenesis, and inflammation. Mutations that convert cellular proto-oncogenes to oncogenes can cause hyperactivation of these signaling pathways, whereas inactivation of tumor suppressors eliminates critical negative regulators of signaling. An examination of the PI3K-Akt and Ras-ERK pathways illustrates how such alterations dysregulate signaling in cancer and produce many of the characteristic features of tumor cells. PMID:25833940

Oncogenes on my mind: ERK and MTOR signaling in cognitive diseases.

PubMed

Krab, Lianne C; Goorden, Susanna M I; Elgersma, Ype

2008-10-01

Defects in rat sarcoma viral oncogene homolog (RAS)-extracellular signal regulated kinase (ERK) and phosphatidylinositol 3-kinase (PI3K)-mammalian target of rapamycin (MTOR) signaling pathways have recently been shown to cause several genetic disorders classified as neuro-cardio-facial-cutaneous (NCFC) and Hamartoma syndromes. Although these pathways are well-known players in cell proliferation and cancer, their role in cognitive function is less appreciated. Here, we focus on the cognitive problems associated with mutations in the RAS-ERK and PI3K-MTOR signaling pathways and on the underlying mechanisms revealed by recent animal studies. Cancer drugs have been shown to reverse the cognitive deficits in mouse models of NCFC and Hamartoma syndromes, raising hopes for clinical trials.

A single mutation in Securin induces chromosomal instability and enhances cell invasion.

PubMed

Mora-Santos, Mar; Castilla, Carolina; Herrero-Ruiz, Joaquín; Giráldez, Servando; Limón-Mortés, M Cristina; Sáez, Carmen; Japón, Miguel Á; Tortolero, Maria; Romero, Francisco

2013-01-01

Pituitary tumour transforming gene (pttg1) encodes Securin, a protein involved in the inhibition of sister chromatid separation binding to Separase until the onset of anaphase. Separase is a cysteine-protease that degrades cohesin to segregate the sister chromatids to opposite poles of the cell. The amount of Securin is strongly regulated because it should allow Separase activation when it is degraded by the anaphase promoting complex/cyclosome, should arrest the cell cycle after DNA damage, when it is degraded through SKP1-CUL1-βTrCP ubiquitin ligase, and its overexpression induces tumour formation and correlates with metastasis in multiple tumours. Securin is a phosphoprotein that contains 32 potentially phosphorylatable residues. We mutated and analysed most of them, and found a single mutant, hSecT60A, that showed enhanced oncogenic properties. Our fluorescence activated cell sorting analysis, fluorescence in situ hybridisation assays, tumour cell migration and invasion experiments and gene expression by microarrays analysis clearly involved hSecT60A in chromosomal instability and cell invasion. These results show, for the first time, that a single mutation in pttg1 is sufficient to trigger the oncogenic properties of Securin. The finding of this point mutation in patients might be used as an effective strategy for early detection of cancer. Copyright © 2012 Elsevier Ltd. All rights reserved.

Genomic instability--an evolving hallmark of cancer.

PubMed

Negrini, Simona; Gorgoulis, Vassilis G; Halazonetis, Thanos D

2010-03-01

Genomic instability is a characteristic of most cancers. In hereditary cancers, genomic instability results from mutations in DNA repair genes and drives cancer development, as predicted by the mutator hypothesis. In sporadic (non-hereditary) cancers the molecular basis of genomic instability remains unclear, but recent high-throughput sequencing studies suggest that mutations in DNA repair genes are infrequent before therapy, arguing against the mutator hypothesis for these cancers. Instead, the mutation patterns of the tumour suppressor TP53 (which encodes p53), ataxia telangiectasia mutated (ATM) and cyclin-dependent kinase inhibitor 2A (CDKN2A; which encodes p16INK4A and p14ARF) support the oncogene-induced DNA replication stress model, which attributes genomic instability and TP53 and ATM mutations to oncogene-induced DNA damage.

MAFA missense mutation causes familial insulinomatosis and diabetes mellitus

PubMed Central

Iacovazzo, Donato; Flanagan, Sarah E.; Walker, Emily; Quezado, Rosana; de Sousa Barros, Fernando Antonio; Johnson, Matthew B.; Wakeling, Matthew; Brändle, Michael; Guo, Min; Dang, Mary N.; Gabrovska, Plamena; Niederle, Bruno; Christ, Emanuel; Jenni, Stefan; Sipos, Bence; Nieser, Maike; Frilling, Andrea; Dhatariya, Ketan; Konukiewitz, Björn; Klöppel, Günter; Stein, Roland; Korbonits, Márta; Ellard, Sian

2018-01-01

The β-cell–enriched MAFA transcription factor plays a central role in regulating glucose-stimulated insulin secretion while also demonstrating oncogenic transformation potential in vitro. No disease-causing MAFA variants have been previously described. We investigated a large pedigree with autosomal dominant inheritance of diabetes mellitus or insulinomatosis, an adult-onset condition of recurrent hyperinsulinemic hypoglycemia caused by multiple insulin-secreting neuroendocrine tumors of the pancreas. Using exome sequencing, we identified a missense MAFA mutation (p.Ser64Phe, c.191C>T) segregating with both phenotypes of insulinomatosis and diabetes. This mutation was also found in a second unrelated family with the same clinical phenotype, while no germline or somatic MAFA mutations were identified in nine patients with sporadic insulinomatosis. In the two families, insulinomatosis presented more frequently in females (eight females/two males) and diabetes more often in males (12 males/four females). Four patients from the index family, including two homozygotes, had a history of congenital cataract and/or glaucoma. The p.Ser64Phe mutation was found to impair phosphorylation within the transactivation domain of MAFA and profoundly increased MAFA protein stability under both high and low glucose concentrations in β-cell lines. In addition, the transactivation potential of p.Ser64Phe MAFA in β-cell lines was enhanced compared with wild-type MAFA. In summary, the p.Ser64Phe missense MAFA mutation leads to familial insulinomatosis or diabetes by impacting MAFA protein stability and transactivation ability. The human phenotypes associated with the p.Ser64Phe MAFA missense mutation reflect both the oncogenic capacity of MAFA and its key role in islet β-cell activity. PMID:29339498

Cervical Cancer Neoantigen Landscape and Immune Activity is Associated with Human Papillomavirus Master Regulators.

PubMed

Qin, Yong; Ekmekcioglu, Suhendan; Forget, Marie-Andrée; Szekvolgyi, Lorant; Hwu, Patrick; Grimm, Elizabeth A; Jazaeri, Amir A; Roszik, Jason

2017-01-01

Human papillomaviruses (HPVs) play a major role in development of cervical cancer, and HPV oncoproteins are being targeted by immunotherapies. Although these treatments show promising results in the clinic, many patients do not benefit or the durability is limited. In addition to HPV antigens, neoantigens derived from somatic mutations may also generate an effective immune response and represent an additional and distinct immunotherapy strategy against this and other HPV-associated cancers. To explore the landscape of neoantigens in cervix cancer, we predicted all possible mutated neopeptides in two large sequencing data sets and analyzed whether mutation and neoantigen load correlate with antigen presentation, infiltrating immune cell types, and a HPV-induced master regulator gene expression signature. We found that targetable neoantigens are detected in most tumors, and there are recurrent mutated peptides from known oncogenic driver genes (KRAS, MAPK1, PIK3CA, ERBB2, and ERBB3) that are predicted to be potentially immunogenic. Our studies show that HPV-induced master regulators are not only associated with HPV load but may also play crucial roles in relation to mutation and neoantigen load, and also the immune microenvironment of the tumor. A subset of these HPV-induced master regulators positively correlated with expression of immune-suppressor molecules such as PD-L1, TGFB1, and IL-10 suggesting that they may be involved in abrogating antitumor response induced by the presence of mutations and neoantigens. Based on these results, we predict that HPV master regulators identified in our study might be potentially effective targets in cervical cancer.

Role of race in oncogenic driver prevalence and outcomes in lung adenocarcinoma: Results from the Lung Cancer Mutation Consortium.

PubMed

Steuer, Conor E; Behera, Madhusmita; Berry, Lynne; Kim, Sungjin; Rossi, Michael; Sica, Gabriel; Owonikoko, Taofeek K; Johnson, Bruce E; Kris, Mark G; Bunn, Paul A; Khuri, Fadlo R; Garon, Edward B; Ramalingam, Suresh S

2016-03-01

The discovery of oncogenic drivers has ushered in a new era for lung cancer, but the role of these mutations in different racial/ethnic minorities has been understudied. The Lung Cancer Mutation Consortium 1 (LCMC1) database was investigated to evaluate the frequency and impact of oncogenic drivers in lung adenocarcinomas in the racial/ethnic minority patient population. Patients with metastatic lung adenocarcinomas from 14 US sites were enrolled in the LCMC1. Tumor samples were collected from 2009 through 2012 with multiplex genotyping performed on 10 oncogenic drivers (KRAS, epidermal growth factor receptor [EGFR], anaplastic lymphoma kinase (ALK) rearrangements, ERBB2 [formerly human epidermal growth factor receptor 2], BRAF, PIK3CA, MET amplification, NRAS, MEK1, and AKT1). Patients were classified as white, Asian, African American (AA), or Latino. The driver mutation frequency, the treatments, and the survival from diagnosis were determined. One thousand seven patients were included. Whites represented the majority (n = 838); there were 60 AAs, 48 Asians, and 28 Latinos. Asian patients had the highest rate of oncogenic drivers with 81% (n = 39), and they were followed by Latinos with 68% (n = 19), whites with 61% (n = 511), and AAs with 53% (n = 32). For AAs, the EGFR mutation frequency was 22%, the KRAS frequency was 17%, and the ALK frequency was 4%. Asian patients were most likely to receive targeted therapies (51% vs 27% for AAs). There were no significant differences in overall survival. Differences were observed in the prevalence of oncogenic drivers in lung adenocarcinomas and in subsequent treatments among racial groups. The lowest frequency of drivers was seen for AA patients; however, more than half of AA patients had a driver, and those treated with targeted therapy had outcomes similar to those of other races. Cancer 2016;122:766-772. © 2015 American Cancer Society. © 2015 American Cancer Society.

Dana-Farber Cancer Institute: Mapping the Function of Rare Oncogenic Variants | Office of Cancer Genomics

Cancer.gov

Although some oncogenes and tumor suppressor genes are recurrently mutated at high frequency, the majority of somatic sequence alterations found in cancers occur at low frequency, and the functional consequences of the majority of these mutated alleles remain unknown. We are developing a scalable systematic approach to interrogate the function of cancer-associated gene variants. Read the abstract

Carcinogen susceptibility is regulated by genome architecture and predicts cancer mutagenesis.

PubMed

García-Nieto, Pablo E; Schwartz, Erin K; King, Devin A; Paulsen, Jonas; Collas, Philippe; Herrera, Rafael E; Morrison, Ashby J

2017-10-02

The development of many sporadic cancers is directly initiated by carcinogen exposure. Carcinogens induce malignancies by creating DNA lesions (i.e., adducts) that can result in mutations if left unrepaired. Despite this knowledge, there has been remarkably little investigation into the regulation of susceptibility to acquire DNA lesions. In this study, we present the first quantitative human genome-wide map of DNA lesions induced by ultraviolet (UV) radiation, the ubiquitous carcinogen in sunlight that causes skin cancer. Remarkably, the pattern of carcinogen susceptibility across the genome of primary cells significantly reflects mutation frequency in malignant melanoma. Surprisingly, DNase-accessible euchromatin is protected from UV, while lamina-associated heterochromatin at the nuclear periphery is vulnerable. Many cancer driver genes have an intrinsic increase in carcinogen susceptibility, including the BRAF oncogene that has the highest mutation frequency in melanoma. These findings provide a genome-wide snapshot of DNA injuries at the earliest stage of carcinogenesis. Furthermore, they identify carcinogen susceptibility as an origin of genome instability that is regulated by nuclear architecture and mirrors mutagenesis in cancer. © 2017 The Authors.

Targeted nanoconjugate co-delivering siRNA and tyrosine kinase inhibitor to KRAS mutant NSCLC dissociates GAB1-SHP2 post oncogene knockdown.

PubMed

Srikar, R; Suresh, Dhananjay; Zambre, Ajit; Taylor, Kristen; Chapman, Sarah; Leevy, Matthew; Upendran, Anandhi; Kannan, Raghuraman

2016-08-17

A tri-block nanoparticle (TBN) comprising of an enzymatically cleavable porous gelatin nanocore encapsulated with gefitinib (tyrosine kinase inhibitor (TKI)) and surface functionalized with cetuximab-siRNA conjugate has been synthesized. Targeted delivery of siRNA to undruggable KRAS mutated non-small cell lung cancer cells would sensitize the cells to TKI drugs and offers an efficient therapy for treating cancer; however, efficient delivery of siRNA and releasing it in cytoplasm remains a major challenge. We have shown TBN can efficiently deliver siRNA to cytoplasm of KRAS mutant H23 Non-Small Cell Lung Cancer (NSCLC) cells for oncogene knockdown; subsequently, sensitizing it to TKI. In the absence of TKI, the nanoparticle showed minimal toxicity suggesting that the cells adapt a parallel GAB1 mediated survival pathway. In H23 cells, activated ERK results in phosphorylation of GAB1 on serine and threonine residues to form GAB1-p85 PI3K complex. In the absence of TKI, knocking down the oncogene dephosphorylated ERK, and negated the complex formation. This event led to tyrosine phosphorylation at Tyr627 domain of GAB1 that regulated EGFR signaling by recruiting SHP2. In the presence of TKI, GAB1-SHP2 dissociation occurs, leading to cell death. The outcome of this study provides a promising platform for treating NSCLC patients harboring KRAS mutation.

Proteome Analysis for Downstream Targets of Oncogenic KRAS - the Potential Participation of CLIC4 in Carcinogenesis in the Lung

PubMed Central

Okudela, Koji; Katayama, Akira; Woo, Tetsukan; Mitsui, Hideaki; Suzuki, Takehisa; Tateishi, Yoko; Umeda, Shigeaki; Tajiri, Michihiko; Masuda, Munetaka; Nagahara, Noriyuki; Kitamura, Hitoshi; Ohashi, Kenichi

2014-01-01

This study investigated the proteome modulated by oncogenic KRAS in immortalized airway epithelial cells. Chloride intracellular channel protein 4 (CLIC4), S100 proteins (S100A2 and S100A11), tropomyosin 2, cathepsin L1, integrinsα3, eukaryotic elongation factor 1, vimentin, and others were discriminated. We here focused on CLIC4 to investigate its potential involvement in carcinogenesis in the lung because previous studies suggested that some chloride channels and chloride channel regulators could function as tumor suppressors. CILC4 protein levels were reduced in some lung cancer cell lines. The restoration of CLIC4 in lung cancer cell lines in which CLIC4 expression was reduced attenuated their growth activity. The immunohistochemical expression of the CLIC4 protein was weaker in primary lung cancer cells than in non-tumorous airway epithelial cells and was occasionally undetectable in some tumors. CLIC4 protein levels were significantly lower in a subtype of mucinous ADC than in others, and were also significantly lower in KRAS-mutated ADC than in EGFR-mutated ADC. These results suggest that the alteration in CLIC4 could be involved in restrictedly the development of a specific fraction of lung adenocarcinomas. The potential benefit of the proteome modulated by oncogenic KRAS to lung cancer research has been demonstrated. PMID:24503901

Targeted nanoconjugate co-delivering siRNA and tyrosine kinase inhibitor to KRAS mutant NSCLC dissociates GAB1-SHP2 post oncogene knockdown

NASA Astrophysics Data System (ADS)

Srikar, R.; Suresh, Dhananjay; Zambre, Ajit; Taylor, Kristen; Chapman, Sarah; Leevy, Matthew; Upendran, Anandhi; Kannan, Raghuraman

2016-08-01

A tri-block nanoparticle (TBN) comprising of an enzymatically cleavable porous gelatin nanocore encapsulated with gefitinib (tyrosine kinase inhibitor (TKI)) and surface functionalized with cetuximab-siRNA conjugate has been synthesized. Targeted delivery of siRNA to undruggable KRAS mutated non-small cell lung cancer cells would sensitize the cells to TKI drugs and offers an efficient therapy for treating cancer; however, efficient delivery of siRNA and releasing it in cytoplasm remains a major challenge. We have shown TBN can efficiently deliver siRNA to cytoplasm of KRAS mutant H23 Non-Small Cell Lung Cancer (NSCLC) cells for oncogene knockdown; subsequently, sensitizing it to TKI. In the absence of TKI, the nanoparticle showed minimal toxicity suggesting that the cells adapt a parallel GAB1 mediated survival pathway. In H23 cells, activated ERK results in phosphorylation of GAB1 on serine and threonine residues to form GAB1-p85 PI3K complex. In the absence of TKI, knocking down the oncogene dephosphorylated ERK, and negated the complex formation. This event led to tyrosine phosphorylation at Tyr627 domain of GAB1 that regulated EGFR signaling by recruiting SHP2. In the presence of TKI, GAB1-SHP2 dissociation occurs, leading to cell death. The outcome of this study provides a promising platform for treating NSCLC patients harboring KRAS mutation.

Oncogenic Kit signalling on the Golgi is suppressed by blocking secretory trafficking with M-COPA in gastrointestinal stromal tumours.

PubMed

Obata, Yuuki; Horikawa, Keita; Shiina, Isamu; Takahashi, Tsuyoshi; Murata, Takatsugu; Tasaki, Yasutaka; Suzuki, Kyohei; Yonekura, Keita; Esumi, Hiroyasu; Nishida, Toshirou; Abe, Ryo

2018-02-28

Most gastrointestinal stromal tumours (GISTs) are caused by constitutively active mutations in Kit tyrosine kinase. The drug imatinib, a specific Kit inhibitor, improves the prognosis of metastatic GIST patients, but these patients become resistant to the drug by acquiring secondary mutations in the Kit kinase domain. We recently reported that a Kit mutant causes oncogenic signals only on the Golgi apparatus in GISTs. In this study, we show that in GIST, 2-methylcoprophilinamide (M-COPA, also known as "AMF-26"), an inhibitor of biosynthetic protein trafficking from the endoplasmic reticulum (ER) to the Golgi, suppresses Kit autophosphorylation at Y703/Y721/Y730/Y936, resulting in blockade of oncogenic signalling. Results of our M-COPA treatment assay show that Kit Y703/Y730/Y936 in the ER are dephosphorylated by protein tyrosine phosphatases (PTPs), thus the ER-retained Kit is unable to activate downstream molecules. ER-localized Kit Y721 is not phosphorylated, but not due to PTPs. Importantly, M-COPA can inhibit the activation of the Kit kinase domain mutant, resulting in suppression of imatinib-resistant GIST proliferation. Our study demonstrates that Kit autophosphorylation is spatio-temporally regulated and may offer a new strategy for treating imatinib-resistant GISTs. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

K-Ras(G12C) inhibitors allosterically control GTP affinity and effector interactions

PubMed Central

Ostrem, Jonathan M.; Peters, Ulf; Sos, Martin L.; Wells, James A.; Shokat, Kevan M.

2014-01-01

Somatic mutations in the small GTPase K-Ras are the most common activating lesions found in human cancer, and are generally associated with poor response to standard therapies1–3. Efforts to target this oncogene directly have faced difficulties owing to its picomolar affinity for GTP/GDP4 and the absence of known allosteric regulatory sites. Oncogenic mutations result in functional activation of Ras family proteins by impairing GTP hydrolysis5,6. With diminished regulation by GTPase activity, the nucleotide state of Ras becomes more dependent on relative nucleotide affinity and concentration. This gives GTP an advantage over GDP7 and increases the proportion of active GTP-bound Ras. Here we report the development of small molecules that irreversibly bind to a common oncogenic mutant, K-Ras(G12C). These compounds rely on the mutant cysteine for binding and therefore do not affect the wild-type protein. Crystallographic studies reveal the formation of a new pocket that is not apparent in previous structures of Ras, beneath the effector binding switch-II region. Binding of these inhibitors to K-Ras(G12C) disrupts both switch-I and switch-II, subverting the native nucleotide preference to favour GDP over GTP and impairing binding to Raf. Our data provide structure-based validation of a new allosteric regulatory site on Ras that is targetable in a mutant-specific manner. PMID:24256730

Roles of FGFR in oral carcinogenesis.

PubMed

Xie, Xiaoyan; Wang, Zhiyong; Chen, Fangman; Yuan, Yao; Wang, Jiayi; Liu, Rui; Chen, Qianming

2016-06-01

Fibroblast growth factor receptors (FGFRs) play essential roles in organ development during the embryonic period, and regulate tissue repair in adults. Accumulating evidence suggests that alterations in FGFR signalling are involved in diverse types of cancer. In this review, we focus on aberrant regulation of FGFRs in pathogenesis of oral squamous cell carcinoma (OSCC), including altered expression and subcellular location, aberrant isoform splicing and mutations. We also provide an overview of oncogenic roles of each FGFR and its downstream signalling pathways in regulating OSCC cell proliferation and metastasis. Finally, we discuss potential application of FGFRs as anti-cancer targets in the preclinical environment and in clinical practice. © 2016 John Wiley & Sons Ltd.

Investigating MUC1/ICAM-1 Binding Induced Signaling in Breast Cancer Metastasis

DTIC Science & Technology

2011-05-01

expected that covalently linked species would remain intact. Reducing (R, + !-mercaptoethanol) and non-reducing (NR, no !-mercaptoethanol) samples were...binding site, containing both proline and arginine residues. We mutated the SH2 and/or putative SH3 binding domains on the MUC1-CFP-Fv plasmid...Structure and regulation of Src family kinases. Oncogene 2004, 23:7918- 7927. 31. Li SSC: Specificity and versatility of SH3 and other proline -recognition

[Analysis of prevalence of point mutations in codon 12 of oncogene K-ras from non-cancerous samples of cervical cytology positive for type 16 or 18 PVH].

PubMed

Golijow, C D; Mourón, S A; Gómez, M A; Dulout, F N

1999-12-01

Ninety-one non cancerous samples from genital specimens positives for VPH 16 or 18 and 27 non-infected samples as controls were studied. Mutations at codon 12 in K-ras gene was analyzed using enriched alelic PCR technique. Among the samples studied 17.58% showed mutations in this codon. Significant differences were observed between the control group (negative DNA-HPV) and positives DNA-HPV samples (p < 0.01). No differences were found between both viral types in relation to the mutation frequency. The presence of mutations in the K-ras gene in non cancerous cytological samples point out new questions about the role of mutations in proto-oncogenes and the development of cervical cancer.

MDM4 is a key therapeutic target in cutaneous melanoma

PubMed Central

Gembarska, Agnieszka; Luciani, Flavie; Fedele, Clare; Russell, Elisabeth A; Dewaele, Michael; Villar, Stéphanie; Zwolinska, Aleksandra; Haupt, Sue; de Lange, Job; Yip, Dana; Goydos, James; Haigh, Jody J; Haupt, Ygal; Larue, Lionel; Jochemsen, Aart; Shi, Hubing; Moriceau, Gatien; Lo, Roger S; Ghanem, Ghanem; Shackleton, Mark; Bernal, Federico; Marine, Jean-Christophe

2013-01-01

The inactivation of the p53 tumor suppressor pathway, which often occurs through mutations in TP53 (encoding tumor protein 53) is a common step in human cancer. However, in melanoma—a highly chemotherapy-resistant disease—TP53 mutations are rare, raising the possibility that this cancer uses alternative ways to overcome p53-mediated tumor suppression. Here we show that Mdm4 p53 binding protein homolog (MDM4), a negative regulator of p53, is upregulated in a substantial proportion (∼65%) of stage I–IV human melanomas and that melanocyte-specific Mdm4 overexpression enhanced tumorigenesis in a mouse model of melanoma induced by the oncogene Nras. MDM4 promotes the survival of human metastatic melanoma by antagonizing p53 proapoptotic function. Notably, inhibition of the MDM4-p53 interaction restored p53 function in melanoma cells, resulting in increased sensitivity to cytotoxic chemotherapy and to inhibitors of the BRAF (V600E) oncogene. Our results identify MDM4 as a key determinant of impaired p53 function in human melanoma and designate MDM4 as a promising target for antimelanoma combination therapy. PMID:22820643

K-ras Mutations as the Earliest Driving Force in a Subset of Colorectal Carcinomas

PubMed Central

MARGETIS, NIKOLAOS; KOULOUKOUSSA, MYRSINI; PAVLOU, KYRIAKI; VRAKAS, SPYRIDON; MARIOLIS-SAPSAKOS, THEODOROS

2017-01-01

K-ras oncogene is a key factor in colorectal cancer. Based on published and our data we propose that K-ras could be the oncogene responsible for the inactivation of the tumor-suppressor gene APC, currently considered as the initial step in colorectal tumorigenesis. K-ras fulfills the criteria of the oncogene-induced DNA damage model, as it can provoke well- established causes for inactivating tumor-suppressors, i.e. DNA double-strand breaks (causing allele deletion) and ROS production (responsible for point mutation). The model we propose is a variation of the currently existing model and hypothesizes that, in a subgroup of colorectal carcinomas, K-ras mutation may precede APC inactivation, representing the earliest driving force and, probably, an early biomarker of colorectal carcinogenesis. This observation is clinically useful, since it may modify the preventive colorectal cancer strategy, restricting numerically patients undergoing colonoscopies to those bearing K-ras mutation in their colorectum, either in benign polyps or the normal accompanying mucosa. PMID:28652417

Oncogene cooperation in tumor maintenance and tumor recurrence in mouse mammary tumors induced by Myc and mutant Kras.

PubMed

Podsypanina, Katrina; Politi, Katerina; Beverly, Levi J; Varmus, Harold E

2008-04-01

Most, if not all, cancers are composed of cells in which more than one gene has a cancer-promoting mutation. Although recent evidence has shown the benefits of therapies targeting a single mutant protein, little attention has been given to situations in which experimental tumors are induced by multiple cooperating oncogenes. Using combinations of doxycycline-inducible and constitutive Myc and mutant Kras transgenes expressed in mouse mammary glands, we show that tumors induced by the cooperative actions of two oncogenes remain dependent on the activity of a single oncogene. Deinduction of either oncogene individually, or both oncogenes simultaneously, led to partial or complete tumor regression. Prolonged remission followed deinduction of Kras(G12D) in the context of continued Myc expression, deinduction of a MYC transgene with continued expression of mutant Kras produced modest effects on life extension, whereas simultaneous deinduction of both MYC and Kras(G12D) transgenes further improved survival. Disease relapse after deinduction of both oncogenes was associated with reactivation of both oncogenic transgenes in all recurrent tumors, often in conjunction with secondary somatic mutations in the tetracycline transactivator transgene, MMTV-rtTA, rendering gene expression doxycycline-independent. These results demonstrate that tumor viability is maintained by each gene in a combination of oncogenes and that targeted approaches will also benefit from combination therapies.

Multiplex picodroplet digital PCR to detect KRAS mutations in circulating DNA from the plasma of colorectal cancer patients.

PubMed

Taly, Valerie; Pekin, Deniz; Benhaim, Leonor; Kotsopoulos, Steve K; Le Corre, Delphine; Li, Xinyu; Atochin, Ivan; Link, Darren R; Griffiths, Andrew D; Pallier, Karine; Blons, Hélène; Bouché, Olivier; Landi, Bruno; Hutchison, J Brian; Laurent-Puig, Pierre

2013-12-01

Multiplex digital PCR (dPCR) enables noninvasive and sensitive detection of circulating tumor DNA with performance unachievable by current molecular-detection approaches. Furthermore, picodroplet dPCR facilitates simultaneous screening for multiple mutations from the same sample. We investigated the utility of multiplex dPCR to screen for the 7 most common mutations in codons 12 and 13 of the KRAS (Kirsten rat sarcoma viral oncogene homolog) oncogene from plasma samples of patients with metastatic colorectal cancer. Fifty plasma samples were tested from patients for whom the primary tumor biopsy tissue DNA had been characterized by quantitative PCR. Tumor characterization revealed that 19 patient tumors had KRAS mutations. Multiplex dPCR analysis of the plasma DNA prepared from these samples identified 14 samples that matched the mutation identified in the tumor, 1 sample contained a different KRAS mutation, and 4 samples had no detectable mutation. Among the tumor samples that were wild type for KRAS, 2 KRAS mutations were identified in the corresponding plasma samples. Duplex dPCR (i.e., wild-type and single-mutation assay) was also used to analyze plasma samples from patients with KRAS-mutated tumors and 5 samples expected to contain the BRAF (v-raf murine sarcoma viral oncogene homolog B) V600E mutation. The results for the duplex analysis matched those for the multiplex analysis for KRAS-mutated samples and, owing to its higher sensitivity, enabled detection of 2 additional samples with low levels of KRAS-mutated DNA. All 5 samples with BRAF mutations were detected. This work demonstrates the clinical utility of multiplex dPCR to screen for multiple mutations simultaneously with a sensitivity sufficient to detect mutations in circulating DNA obtained by noninvasive blood collection.

Targeting reactive oxygen species in development and progression of pancreatic cancer

PubMed Central

Durand, Nisha; Storz, Peter

2017-01-01

Introduction Pancreatic ductal adenocarcinoma (PDA) is characterized by expression of oncogenic KRas which drives all aspects of tumorigenesis. Oncogenic KRas induces the formation of reactive oxygen species (ROS) which have been implicated in initiation and progression of PDA. To facilitate tumor promoting levels and to avoid oncogene-induced senescence or cytotoxicity, ROS homeostasis in PDA cells is balanced by additional up-regulation of antioxidant systems. Areas Covered We examine the sources of ROS in PDA, the mechanisms by which ROS homeostasis is maintained, and the biological consequences of ROS in PDA. Additionally, we discuss the potential mechanisms for targeting ROS homoeostasis as a point of therapeutic intervention. An extensive review of the relevant literature as it relates to the topic was conducted using PubMed. Expert Commentary Even though oncogenic mutations in the KRAS gene have been detected in over 95% of human pancreatic adenocarcinoma, targeting its gene product, KRas, has been difficult. The dependency of PDA cells on balancing ROS homeostasis could be an angle for new prevention or treatment strategies. These include use of antioxidants to prevent formation or progression of precancerous lesions, or methods to increase ROS in tumor cells to toxic levels. PMID:27841037

Targeting Bcl-2 stability to sensitize cells harboring oncogenic ras.

PubMed

Peng, Bo; Ganapathy, Suthakar; Shen, Ling; Huang, Junchi; Yi, Bo; Zhou, Xiaodong; Dai, Wei; Chen, Changyan

2015-09-08

The pro-survival factor Bcl-2 and its family members are critical determinants of the threshold of the susceptibility of cells to apoptosis. Studies are shown that cells harboring an oncogenic ras were extremely sensitive to the inhibition of protein kinase C (PKC) and Bcl-2 could antagonize this apoptotic process. However, it remains unrevealed how Bcl-2 is being regulated in this apoptotic process. In this study, we investigate the role of Bcl-2 stability in sensitizing the cells harboring oncogenic K-ras to apoptosis triggered by PKC inhibitor GO6976. We demonstrated that Bcl-2 in Swiss3T3 cells ectopically expressing or murine lung cancer LKR cells harboring K-ras rapidly underwent ubiquitin-dependent proteasome pathway after the treatment of GO6976, accompanied with induction of apoptosis. In this process, Bcl-2 formed the complex with Keap-1 and Cul3. The mutation of serine-17 and deletion of BH-2 or 4 was required for Bcl-2 ubiquitination and degradation, which elevate the signal threshold for the induction of apoptosis in the cells following PKC inhibition. Thus, Bcl-2 appears an attractive target for the induction of apoptosis by PKC inhibition in cancer cells expressing oncogenic K-ras.

The PDZ-binding motif of Yes-associated protein is required for its co-activation of TEAD-mediated CTGF transcription and oncogenic cell transforming activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shimomura, Tadanori; Miyamura, Norio; Hata, Shoji

2014-01-17

Highlights: •Loss of the PDZ-binding motif inhibits constitutively active YAP (5SA)-induced oncogenic cell transformation. •The PDZ-binding motif of YAP promotes its nuclear localization in cultured cells and mouse liver. •Loss of the PDZ-binding motif inhibits YAP (5SA)-induced CTGF transcription in cultured cells and mouse liver. -- Abstract: YAP is a transcriptional co-activator that acts downstream of the Hippo signaling pathway and regulates multiple cellular processes, including proliferation. Hippo pathway-dependent phosphorylation of YAP negatively regulates its function. Conversely, attenuation of Hippo-mediated phosphorylation of YAP increases its ability to stimulate proliferation and eventually induces oncogenic transformation. The C-terminus of YAP contains amore » highly conserved PDZ-binding motif that regulates YAP’s functions in multiple ways. However, to date, the importance of the PDZ-binding motif to the oncogenic cell transforming activity of YAP has not been determined. In this study, we disrupted the PDZ-binding motif in the YAP (5SA) protein, in which the sites normally targeted by Hippo pathway-dependent phosphorylation are mutated. We found that loss of the PDZ-binding motif significantly inhibited the oncogenic transformation of cultured cells induced by YAP (5SA). In addition, the increased nuclear localization of YAP (5SA) and its enhanced activation of TEAD-dependent transcription of the cell proliferation gene CTGF were strongly reduced when the PDZ-binding motif was deleted. Similarly, in mouse liver, deletion of the PDZ-binding motif suppressed nuclear localization of YAP (5SA) and YAP (5SA)-induced CTGF expression. Taken together, our results indicate that the PDZ-binding motif of YAP is critical for YAP-mediated oncogenesis, and that this effect is mediated by YAP’s co-activation of TEAD-mediated CTGF transcription.« less

Noncoding somatic and inherited single-nucleotide variants converge to promote ESR1 expression in breast cancer.

PubMed

Bailey, Swneke D; Desai, Kinjal; Kron, Ken J; Mazrooei, Parisa; Sinnott-Armstrong, Nicholas A; Treloar, Aislinn E; Dowar, Mark; Thu, Kelsie L; Cescon, David W; Silvester, Jennifer; Yang, S Y Cindy; Wu, Xue; Pezo, Rossanna C; Haibe-Kains, Benjamin; Mak, Tak W; Bedard, Philippe L; Pugh, Trevor J; Sallari, Richard C; Lupien, Mathieu

2016-10-01

Sustained expression of the estrogen receptor-α (ESR1) drives two-thirds of breast cancer and defines the ESR1-positive subtype. ESR1 engages enhancers upon estrogen stimulation to establish an oncogenic expression program. Somatic copy number alterations involving the ESR1 gene occur in approximately 1% of ESR1-positive breast cancers, suggesting that other mechanisms underlie the persistent expression of ESR1. We report significant enrichment of somatic mutations within the set of regulatory elements (SRE) regulating ESR1 in 7% of ESR1-positive breast cancers. These mutations regulate ESR1 expression by modulating transcription factor binding to the DNA. The SRE includes a recurrently mutated enhancer whose activity is also affected by rs9383590, a functional inherited single-nucleotide variant (SNV) that accounts for several breast cancer risk-associated loci. Our work highlights the importance of considering the combinatorial activity of regulatory elements as a single unit to delineate the impact of noncoding genetic alterations on single genes in cancer.

Dana-Farber Cancer Institute: Mapping the Function of Rare Oncogenic Variants | Office of Cancer Genomics

Cancer.gov

Although some oncogenes and tumor suppressor genes are recurrently mutated at high frequency, the majority of somatic sequence alterations found in cancers occur at low frequency, and the functional consequences of the majority of these mutated alleles remain unknown. We are developing a scalable systematic approach to interrogate the function of cancer-associated gene variants. Read the abstract: Kim et al., 2016

Oncogenic Kras initiates leukemia in hematopoietic stem cells.

PubMed

Sabnis, Amit J; Cheung, Laurene S; Dail, Monique; Kang, Hio Chung; Santaguida, Marianne; Hermiston, Michelle L; Passegué, Emmanuelle; Shannon, Kevin; Braun, Benjamin S

2009-03-17

How oncogenes modulate the self-renewal properties of cancer-initiating cells is incompletely understood. Activating KRAS and NRAS mutations are among the most common oncogenic lesions detected in human cancer, and occur in myeloproliferative disorders (MPDs) and leukemias. We investigated the effects of expressing oncogenic Kras(G12D) from its endogenous locus on the proliferation and tumor-initiating properties of murine hematopoietic stem and progenitor cells. MPD could be initiated by Kras(G12D) expression in a highly restricted population enriched for hematopoietic stem cells (HSCs), but not in common myeloid progenitors. Kras(G12D) HSCs demonstrated a marked in vivo competitive advantage over wild-type cells. Kras(G12D) expression also increased the fraction of proliferating HSCs and reduced the overall size of this compartment. Transplanted Kras(G12D) HSCs efficiently initiated acute T-lineage leukemia/lymphoma, which was associated with secondary Notch1 mutations in thymocytes. We conclude that MPD-initiating activity is restricted to the HSC compartment in Kras(G12D) mice, and that distinct self-renewing populations with cooperating mutations emerge during cancer progression.

Effects of HRAS oncogene on cell cycle progression in a cervical cancer-derived cell line.

PubMed

Córdova-Alarcón, Emilio; Centeno, Federico; Reyes-Esparza, Jorge; García-Carrancá, Alejandro; Garrido, Efraín

2005-01-01

Human papillomavirus (HPV) infection is the most prevalent factor in anogenital cancers. However, epidemiological surveys and molecular data indicate that viral presence is not enough to induce cervical cancer, suggesting that cellular factors could play a key role. One of the most important genes involved in cancer development is the RAS oncogene, and activating mutations in this gene have been associated with HPV infection and cervical neoplasia. Thus, we determined the effect of HRAS oncogene expression on cell proliferation in a cell line immortalized by E6 and E7 oncogenes. HPV positive human cervical carcinoma-derived cell lines (HeLa), previously transfected with the HRAS oncogene or the empty vector, were used. We first determined the proliferation rate and cell cycle profile of these cells by using flow cytometry and BrdU incorporation assays. In order to determine the signaling pathway regulated by HRAS and implicated in the alteration of proliferation of these cells, we used specific chemical inhibitors to inactivate the Raf and PI3K pathways. We observed that HeLa cells stably transfected with oncogenic HRAS progressed faster than control cells on the cell cycle by reducing their G1 phase. Additionally, HRAS overexpression accelerated the G1/S transition. Specific chemical inhibitors for PI3K and MEK activities indicated that both PI3K/AKT and RAF/MEK/ERK pathways are involved in the HRAS oncogene-induced reduction of the G1 phase. Our results suggest that the HRAS oncogene could play an important role in the development of cervical cancer, in addition to the presence of HPV, by reducing the G1 phase and accelerating the G1/S transition of infected cells.

RAS/ERK modulates TGFbeta-regulated PTEN expression in human pancreatic adenocarcinoma cells.

PubMed

Chow, Jimmy Y C; Quach, Khai T; Cabrera, Betty L; Cabral, Jennifer A; Beck, Stayce E; Carethers, John M

2007-11-01

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is rarely mutated in pancreatic cancers, but its regulation by transforming growth factor (TGF)-beta might mediate growth suppression and other oncogenic actions. Here, we examined the role of TGFbeta and the effects of oncogenic K-RAS/ERK upon PTEN expression in the absence of SMAD4. We utilized two SMAD4-null pancreatic cell lines, CAPAN-1 (K-RAS mutant) and BxPc-3 (WT-K-RAS), both of which express TGFbeta surface receptors. Cells were treated with TGFbeta1 and separated into cytosolic/nuclear fractions for western blotting with phospho-SMAD2, SMAD 2, 4 phospho-ATP-dependent tyrosine kinases (Akt), Akt and PTEN antibodies. PTEN mRNA levels were assessed by reverse transcriptase-polymerase chain reaction. The MEK1 inhibitor, PD98059, was used to block the downstream action of oncogenic K-RAS/ERK, as was a dominant-negative (DN) K-RAS construct. TGFbeta increased phospho-SMAD2 in both cytosolic and nuclear fractions. PD98059 treatment further increased phospho-SMAD2 in the nucleus of both pancreatic cell lines, and DN-K-RAS further improved SMAD translocation in K-RAS mutant CAPAN cells. TGFbeta treatment significantly suppressed PTEN protein levels concomitant with activation of Akt by 48 h through transcriptional reduction of PTEN mRNA that was evident by 6 h. TGFbeta-induced PTEN suppression was reversed by PD98059 and DN-K-RAS compared with treatments without TGFbeta. TGFbeta-induced PTEN expression was inversely related to cellular proliferation. Thus, oncogenic K-RAS/ERK in pancreatic adenocarcinoma facilitates TGFbeta-induced transcriptional down-regulation of the tumor suppressor PTEN in a SMAD4-independent manner and could constitute a signaling switch mechanism from growth suppression to growth promotion in pancreatic cancers.

Comprehensive Characterization of Oncogenic Drivers in Asian Lung Adenocarcinoma.

PubMed

Li, Shiyong; Choi, Yoon-La; Gong, Zhuolin; Liu, Xiao; Lira, Maruja; Kan, Zhengyan; Oh, Ensel; Wang, Jian; Ting, Jason C; Ye, Xiangsheng; Reinhart, Christoph; Liu, Xiaoqiao; Pei, Yunfei; Zhou, Wei; Chen, Ronghua; Fu, Shijun; Jin, Gang; Jiang, Awei; Fernandez, Julio; Hardwick, James; Kang, Min Woong; I, Hoseok; Zheng, Hancheng; Kim, Jhingook; Mao, Mao

2016-12-01

The incidence rate of lung adenocarcinoma (LUAD), the predominant histological subtype of lung cancer, is elevated in Asians, particularly in female nonsmokers. The mutation patterns in LUAD in Asians might be distinct from those in LUAD in whites. We profiled 271 resected LUAD tumors (mainly stage I) to characterize the genomic landscape of LUAD in Asians with a focus on female nonsmokers. Mutations in EGFR, KRAS, erb-b2 receptor tyrosine kinase 2 gene (ERBB2), and BRAF; gene fusions involving anaplastic lymphoma receptor tyrosine kinase gene (ALK), ROS1, and ret proto-oncogene (RET); and Met Proto-Oncogene Tyrosine Kinase (MET) exon 14 skipping were the major drivers in LUAD in Asians, exhibiting mutually exclusive and differing prevalence from those reported in studies of LUAD in non-Asians. In addition, we identified a novel mutational signature of XNX (the mutated base N in the middle flanked by two identical bases at the 5' and 3' positions) that was overrepresented in LUAD tumors in nonsmokers and negatively correlated with the overall mutational frequency. In this cohort, approximately 85% of individuals have known driver mutations (EGFR 59.4%, KRAS 7.4%, ALK 7.4%, ERBB2 2.6%, ROS1 2.2%, RET 2.2%, MET 1.8%, BRAF 1.1%, and NRAS 0.4%). Seventy percent of smokers and 90% of nonsmokers had defined oncogenic drivers matching the U.S. Food and Drug Administration-approved targeted therapies. Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peltomaeki, Paeivi, E-mail: Paivi.Peltomaki@Helsinki.Fi

Cancer is traditionally viewed as a disease of abnormal cell proliferation controlled by a series of mutations. Mutations typically affect oncogenes or tumor suppressor genes thereby conferring growth advantage. Genomic instability facilitates mutation accumulation. Recent findings demonstrate that activation of oncogenes and inactivation of tumor suppressor genes, as well as genomic instability, can be achieved by epigenetic mechanisms as well. Unlike genetic mutations, epimutations do not change the base sequence of DNA and are potentially reversible. Similar to genetic mutations, epimutations are associated with specific patterns of gene expression that are heritable through cell divisions. Knudson's hypothesis postulates that inactivationmore » of tumor suppressor genes requires two hits, with the first hit occurring either in somatic cells (sporadic cancer) or in the germline (hereditary cancer) and the second one always being somatic. Studies on hereditary and sporadic forms of colorectal carcinoma have made it evident that, apart from genetic mutations, epimutations may serve as either hit or both. Furthermore, recent next-generation sequencing studies show that epigenetic genes, such as those encoding histone modifying enzymes and subunits for chromatin remodeling systems, are themselves frequent targets of somatic mutations in cancer and can act like tumor suppressor genes or oncogenes. This review discusses genetic vs. epigenetic origin of cancer, including cancer susceptibility, in light of recent discoveries. Situations in which mutations and epimutations occur to serve analogous purposes are highlighted.« less

Molecular Cell Biology of Apoptosis and Necroptosis in Cancer.

PubMed

Dillon, Christopher P; Green, Douglas R

Cell death is a major mechanism to eliminate cells in which DNA is damaged, organelles are stressed, or oncogenes are overexpressed, all events that would otherwise predispose cells to oncogenic transformation. The pathways that initiate and execute cell death are complex, genetically encoded, and subject to significant regulation. Consequently, while these pathways are often mutated in malignancy, there is considerable interest in inducing cell death in tumor cells as therapy. This chapter addresses our current understanding of molecular mechanisms contributing to two cell death pathways, apoptotic cell death and necroptosis, a regulated form of necrotic cell death. Apoptosis can be induced by a wide variety of signals, leading to protease activation that dismantles the cell. We discuss the physiological importance of each apoptosis pathway and summarize their known roles in cancer suppression and the current efforts at targeting each pathway therapeutically. The intricate mechanistic link between death receptor-mediated apoptosis and necroptosis is described, as well as the potential opportunities for utilizing necroptosis in the treatment of malignancy.

JAK signaling globally counteracts heterochromatic gene silencing.

PubMed

Shi, Song; Calhoun, Healani C; Xia, Fan; Li, Jinghong; Le, Long; Li, Willis X

2006-09-01

The JAK/STAT pathway has pleiotropic roles in animal development, and its aberrant activation is implicated in multiple human cancers. JAK/STAT signaling effects have been attributed largely to direct transcriptional regulation by STAT of specific target genes that promote tumor cell proliferation or survival. We show here in a Drosophila melanogaster hematopoietic tumor model, however, that JAK overactivation globally disrupts heterochromatic gene silencing, an epigenetic tumor suppressive mechanism. This disruption allows derepression of genes that are not direct targets of STAT, as evidenced by suppression of heterochromatin-mediated position effect variegation. Moreover, mutations in the genes encoding heterochromatin components heterochromatin protein 1 (HP1) and Su(var)3-9 enhance tumorigenesis induced by an oncogenic JAK kinase without affecting JAK/STAT signaling. Consistently, JAK loss of function enhances heterochromatic gene silencing, whereas overexpressing HP1 suppresses oncogenic JAK-induced tumors. These results demonstrate that the JAK/STAT pathway regulates cellular epigenetic status and that globally disrupting heterochromatin-mediated tumor suppression is essential for tumorigenesis induced by JAK overactivation.

JAK signaling globally counteracts heterochromatic gene silencing

PubMed Central

Shi, Song; Calhoun, Healani C; Xia, Fan; Li, Jinghong; Le, Long; Li, Willis X

2011-01-01

The JAK/STAT pathway has pleiotropic roles in animal development, and its aberrant activation is implicated in multiple human cancers1–3. JAK/STAT signaling effects have been attributed largely to direct transcriptional regulation by STAT of specific target genes that promote tumor cell proliferation or survival. We show here in a Drosophila melanogaster hematopoietic tumor model, however, that JAK overactivation globally disrupts heterochromatic gene silencing, an epigenetic tumor suppressive mechanism4. This disruption allows derepression of genes that are not direct targets of STAT, as evidenced by suppression of heterochromatin-mediated position effect variegation. Moreover, mutations in the genes encoding heterochromatin components heterochromatin protein 1 (HP1) and Su(var)3-9 enhance tumorigenesis induced by an oncogenic JAK kinase without affecting JAK/STAT signaling. Consistently, JAK loss of function enhances heterochromatic gene silencing, whereas overexpressing HP1 suppresses oncogenic JAK-induced tumors. These results demonstrate that the JAK/STAT pathway regulates cellular epigenetic status and that globally disrupting heterochromatin-mediated tumor suppression is essential for tumorigenesis induced by JAK overactivation. PMID:16892059

Molecular profiling of appendiceal epithelial tumors using massively parallel sequencing to identify somatic mutations.

PubMed

Liu, Xiaoying; Mody, Kabir; de Abreu, Francine B; Pipas, J Marc; Peterson, Jason D; Gallagher, Torrey L; Suriawinata, Arief A; Ripple, Gregory H; Hourdequin, Kathryn C; Smith, Kerrington D; Barth, Richard J; Colacchio, Thomas A; Tsapakos, Michael J; Zaki, Bassem I; Gardner, Timothy B; Gordon, Stuart R; Amos, Christopher I; Wells, Wendy A; Tsongalis, Gregory J

2014-07-01

Some epithelial neoplasms of the appendix, including low-grade appendiceal mucinous neoplasm and adenocarcinoma, can result in pseudomyxoma peritonei (PMP). Little is known about the mutational spectra of these tumor types and whether mutations may be of clinical significance with respect to therapeutic selection. In this study, we identified somatic mutations using the Ion Torrent AmpliSeq Cancer Hotspot Panel v2. Specimens consisted of 3 nonneoplastic retention cysts/mucocele, 15 low-grade mucinous neoplasms (LAMNs), 8 low-grade/well-differentiated mucinous adenocarcinomas with pseudomyxoma peritonei, and 12 adenocarcinomas with/without goblet cell/signet ring cell features. Barcoded libraries were prepared from up to 10 ng of extracted DNA and multiplexed on single 318 chips for sequencing. Data analysis was performed using Golden Helix SVS. Variants that remained after the analysis pipeline were individually interrogated using the Integrative Genomics Viewer. A single Janus kinase 3 (JAK3) mutation was detected in the mucocele group. Eight mutations were identified in the V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and GNAS complex locus (GNAS) genes among LAMN samples. Additional gene mutations were identified in the AKT1 (v-akt murine thymoma viral oncogene homolog 1), APC (adenomatous polyposis coli), JAK3, MET (met proto-oncogene), phosphatidylinositol-4,5-bisphosphate 3-kinase (PIK3CA), RB1 (retinoblastoma 1), STK11 (serine/threonine kinase 11), and tumor protein p53 (TP53) genes. Among the PMPs, 6 mutations were detected in the KRAS gene and also in the GNAS, TP53, and RB1 genes. Appendiceal cancers showed mutations in the APC, ATM (ataxia telangiectasia mutated), KRAS, IDH1 [isocitrate dehydrogenase 1 (NADP+)], NRAS [neuroblastoma RAS viral (v-ras) oncogene homolog], PIK3CA, SMAD4 (SMAD family member 4), and TP53 genes. Our results suggest molecular heterogeneity among epithelial tumors of the appendix. Next generation sequencing efforts have identified mutational spectra in several subtypes of these tumors that may suggest a phenotypic heterogeneity showing mutations that are relevant for targeted therapies. © 2014 The American Association for Clinical Chemistry.

Endogenous oncogenic Nras mutation initiates hematopoietic malignancies in a dose- and cell type-dependent manner

PubMed Central

Wang, Jinyong; Liu, Yangang; Li, Zeyang; Wang, Zhongde; Tan, Li Xuan; Ryu, Myung-Jeom; Meline, Benjamin; Du, Juan; Young, Ken H.; Ranheim, Erik; Chang, Qiang

2011-01-01

Both monoallelic and biallelic oncogenic NRAS mutations are identified in human leukemias, suggesting a dose-dependent role of oncogenic NRAS in leukemogenesis. Here, we use a hypomorphic oncogenic Nras allele and a normal oncogenic Nras allele (Nras G12Dhypo and Nras G12D, respectively) to create a gene dose gradient ranging from 25% to 200% of endogenous Nras G12D/+. Mice expressing Nras G12Dhypo/G12Dhypo develop normally and are tumor-free, whereas early embryonic expression of Nras G12D/+ is lethal. Somatic expression of Nras G12D/G12D but not Nras G12D/+ leads to hyperactivation of ERK, excessive proliferation of myeloid progenitors, and consequently an acute myeloproliferative disease. Using a bone marrow transplant model, we previously showed that ∼ 95% of animals receiving Nras G12D/+ bone marrow cells develop chronic myelomonocytic leukemia (CMML), while ∼ 8% of recipients develop acute T-cell lymphoblastic leukemia/lymphoma [TALL] (TALL-het). Here we demonstrate that 100% of recipients transplanted with Nras G12D/G12D bone marrow cells develop TALL (TALL-homo). Although both TALL-het and -homo tumors acquire Notch1 mutations and are sensitive to a γ-secretase inhibitor, endogenous Nras G12D/+ signaling promotes TALL through distinct genetic mechanism(s) from Nras G12D/G12D. Our data indicate that the tumor transformation potential of endogenous oncogenic Nras is both dose- and cell type-dependent. PMID:21586752

Risk for Sporadic Breast Cancer in Ataxia Telangiectasia Heterozygotes

DTIC Science & Technology

2002-08-01

gene, due to a loss of function mutation in one of the 2 alleles and found in about 1% of the general population, confers a significant increase in... loss of wild type ATM expression rather than mutational inactivation could be expected. With this rationale, we undertook a comprehensive ATM expression...deficient tumor cells with activated oncogenic pathways, clonal outgrowth favors loss of p73 function. Taken together, this data shows that oncogenes can

Mechanisms of NF-κB deregulation in lymphoid malignancies.

PubMed

Krappmann, Daniel; Vincendeau, Michelle

2016-08-01

Deregulations promoting constitutive activation of canonical and non-canonical NF-κB signaling are a common feature of many lymphoid malignancies. Due to their cellular origin and the pivotal role of NF-κB for the normal function of B lymphocytes, B-cell malignancies are particularly prone to genetic aberrations that affect the pathway. Key positive regulators of NF-κB signaling can act as oncogenes that are often prone to chromosomal translocation, amplifications or activating mutations. Negative regulators of NF-κB have tumor suppressor functions and are frequently inactivated either by genomic deletions or point mutations. Whereas some aberrations are found in a variety of different lymphoid malignancies, some oncogenic alterations are very restricted to distinct lymphoma subsets, reflecting the clonal and cellular origin of specific lymphoma entities. NF-κB activation in many lymphoma cells is also driven by the microenvironment or chronic signaling that does not rely on genetic alterations. A number of drugs that target the NF-κB pathway are in preclinical or clinical development, revealing that there will be new options for therapies in the future. Since each lymphoma entity utilizes distinct mechanisms to activate NF-κB, a major challenge is to elucidate the exact pathological processes in order to faithfully predict clinical responses to the different therapeutic approaches. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oncogenic PIK3CA mutations occur in epidermal nevi and seborrheic keratoses with a characteristic mutation pattern

PubMed Central

Hafner, Christian; López-Knowles, Elena; Luis, Nuno M.; Toll, Agustí; Baselga, Eulàlia; Fernández-Casado, Alex; Hernández, Silvia; Ribé, Adriana; Mentzel, Thomas; Stoehr, Robert; Hofstaedter, Ferdinand; Landthaler, Michael; Vogt, Thomas; Pujol, Ramòn M.; Hartmann, Arndt; Real, Francisco X.

2007-01-01

Activating mutations of the p110 α subunit of PI3K (PIK3CA) oncogene have been identified in a broad spectrum of malignant tumors. However, their role in benign or preneoplastic conditions is unknown. Activating FGF receptor 3 (FGFR3) mutations are common in benign skin lesions, either as embryonic mutations in epidermal nevi (EN) or as somatic mutations in seborrheic keratoses (SK). FGFR3 mutations are also common in low-grade malignant bladder tumors, where they often occur in association with PIK3CA mutations. Therefore, we examined exons 9 and 20 of PIK3CA and FGFR3 hotspot mutations in EN (n = 33) and SK (n = 62), two proliferative skin lesions lacking malignant potential. Nine of 33 (27%) EN harbored PIK3CA mutations; all cases showed the E545G substitution, which is uncommon in cancers. In EN, R248C was the only FGFR3 mutation identified. By contrast, 10 of 62 (16%) SK revealed the typical cancer-associated PIK3CA mutations E542K, E545K, and H1047R. The same lesions displayed a wide range of FGFR3 mutations. Corresponding unaffected tissue was available for four EN and two mutant SK: all control samples displayed a WT sequence, confirming the somatic nature of the mutations found in lesional tissue. Forty of 95 (42%) lesions showed at least one mutation in either gene. PIK3CA and FGFR3 mutations displayed an independent distribution; 5/95 lesions harbored mutations in both genes. Our findings suggest that, in addition to their role in cancer, oncogenic PIK3CA mutations contribute to the pathogenesis of skin tumors lacking malignant potential. The remarkable genotype–phenotype correlation as observed in this study points to a distinct etiopathogenesis of the mutations in keratinocytes occuring either during fetal development or in adult life. PMID:17673550

Emerging therapeutic targets in myeloproliferative neoplasms and peripheral T-cell leukemia and lymphomas

PubMed Central

Orlova, Anna; Wingelhofer, Bettina; Neubauer, Heidi A.; Maurer, Barbara; Berger-Becvar, Angelika; Keserű, György Miklós; Gunning, Patrick T.; Valent, Peter; Moriggl, Richard

2018-01-01

ABSTRACT Introduction: Hematopoietic neoplasms are often driven by gain-of-function mutations of the JAK-STAT pathway together with mutations in chromatin remodeling and DNA damage control pathways. The interconnection between the JAK-STAT pathway, epigenetic regulation or DNA damage control is still poorly understood in cancer cell biology. Areas covered: Here, we focus on a broader description of mutational insights into myeloproliferative neoplasms and peripheral T-cell leukemia and lymphomas, since sequencing efforts have identified similar combinations of driver mutations in these diseases covering different lineages. We summarize how these pathways might be interconnected in normal or cancer cells, which have lost differentiation capacity and drive oncogene transcription. Expert opinion: Due to similarities in driver mutations including epigenetic enzymes, JAK-STAT pathway activation and mutated checkpoint control through TP53, we hypothesize that similar therapeutic approaches could be of benefit in these diseases. We give an overview of how driver mutations in these malignancies contribute to hematopoietic cancer initiation or progression, and how these pathways can be targeted with currently available tools. PMID:29148847

EGFR, ALK, RET, KRAS and BRAF alterations in never-smokers with non-small cell lung cancer.

PubMed

Dong, Y U; Ren, Weihong; Qi, Jun; Jin, B O; Li, Ying; Tao, Huiqing; Xu, Ren; Li, Yanqing; Zhang, Qinxian; Han, Baohui

2016-04-01

Non-small cell lung cancer (NSCLC), caused by various mutations in a spectrum of cancer driver genes, may have distinct pathological characteristics and drug responses. Extensive genetic screening and pathological characterization is required for the design of customized therapies to improve patient outcomes. Notably, NSCLC in never-smokers exhibits distinctive clinicopathological features, which are frequently associated with tumorigenic mutations, and thus may be treated as a unique disease entity. However, to the best of our knowledge, these mutations have not been extensively and accurately characterized in an NSCLC study with a large sample size. Therefore, the present study enrolled a large cohort of NSCLC patients, which consisted of 358 never-smokers, for the screening of genetic alterations in the epidermal growth factor receptor (EGFR), ret proto-oncogene (RET), anaplastic lymphoma kinase (ALK), Kirsten rat sarcoma viral oncogene homolog (KRAS) and B-Raf proto-oncogene serine/threonine kinase (BRAF) tumorigenic genes. It was identified that the mutation rate was 47.8, 7.5, 3.6, 1.4 and 0.3% for EGFR, ALK, KRAS, RET and BRAF, respectively. In addition, clinicopathological features associated with these mutations were characterized. EGFR mutations were more frequently observed in female and older patients. By contrast, KRAS mutations were more frequently detected in male patients, and ALK and RET translocations in younger patients. The cancer cells were frequently well-differentiated in carcinoma cases exhibiting EGFR mutations, however, were less differentiated in those with ALK translocations. In conclusion, the present study determined the frequency of oncogenic alterations and associated clinicopathological features in NSCLC exhibited by never-smokers using a large sample size. The results of the present study may enrich our knowledge of NSCLC in never-smokers and provide useful insights for improvement of the outcome of molecularly targeted therapies for the treatment of NSCLC.

Germ line mutation analysis in families with multiple endocrine neoplasia type 2A or familial medullary thyroid carcinoma.

PubMed

Karga, H J; Karayianni, M K; Linos, D A; Tseleni, S C; Karaiskos, K D; Papapetrou, P D

1998-10-01

The RET proto-oncogene has been identified as the multiple endocrine neoplasia type 2 disease gene. An association between specific RET mutation and disease phenotype has been reported. We present the phenotype-genotype of 12 Greek families with multiple endocrine neoplasia type 2A (MEN 2A) or familial medullary thyroid carcinoma (FMTC). Seventy members were studied and DNA analysis for RET mutations was performed in fifty-eight of them. Exons 10, 11, 13, 14 and 16 of the RET proto-oncogene were analyzed by single strand conformation polymorphism analysis, direct DNA sequencing and/or restriction enzyme analysis. No mutations of the RET proto-oncogene were identified in 1 of 9 families with MEN 2A and in the 3 families with FMTC. In 7 MEN 2A families, the mutation was demonstrated in codon 634 and in 1 family it was demonstrated in codon 620. There was a low frequency, about 8%, of hyperparathyroidism associated with MEN 2A. The specific causative mutations for pararthyroid disease were C634R or C634Y. Among the MEN 2A individuals there was one case with de novo C634R mutation and one case, C634Y, with cutaneous lichen amyloidosis which predated by 24 years the diagnosis of MEN 2A. In 2 children who were MEN 2A gene carriers, microscopic medullary thyroid carcinomas were found. These data show a low frequency of hyperparathyroidism in our cases and provide further evidence that individuals with C634R as well as with C634Y mutations of the RET proto-oncogene could be at risk for parathyroid disease. Cutaneous lichen amyloidosis could be an early feature of MEN 2A. Additionally, direct DNA testing provided an opportunity to resect medullary thyroid carcinoma at an early stage.

Muscle RAS oncogene homolog (MRAS) recurrent mutation in Borrmann type IV gastric cancer.

PubMed

Yasumoto, Makiko; Sakamoto, Etsuko; Ogasawara, Sachiko; Isobe, Taro; Kizaki, Junya; Sumi, Akiko; Kusano, Hironori; Akiba, Jun; Torimura, Takuji; Akagi, Yoshito; Itadani, Hiraku; Kobayashi, Tsutomu; Hasako, Shinichi; Kumazaki, Masafumi; Mizuarai, Shinji; Oie, Shinji; Yano, Hirohisa

2017-01-01

The prognosis of patients with Borrmann type IV gastric cancer (Type IV) is extremely poor. Thus, there is an urgent need to elucidate the molecular mechanisms underlying the oncogenesis of Type IV and to identify new therapeutic targets. Although previous studies using whole-exome and whole-genome sequencing have elucidated genomic alterations in gastric cancer, none has focused on comprehensive genetic analysis of Type IV. To discover cancer-relevant genes in Type IV, we performed whole-exome sequencing and genome-wide copy number analysis on 13 patients with Type IV. Exome sequencing identified 178 somatic mutations in protein-coding sequences or at splice sites. Among the mutations, we found a mutation in muscle RAS oncogene homolog (MRAS), which is predicted to cause molecular dysfunction. MRAS belongs to the Ras subgroup of small G proteins, which includes the prototypic RAS oncogenes. We analyzed an additional 46 Type IV samples to investigate the frequency of MRAS mutation. There were eight nonsynonymous mutations (mutation frequency, 17%), showing that MRAS is recurrently mutated in Type IV. Copy number analysis identified six focal amplifications and one homozygous deletion, including insulin-like growth factor 1 receptor (IGF1R) amplification. The samples with IGF1R amplification had remarkably higher IGF1R mRNA and protein expression levels compared with the other samples. This is the first report of MRAS recurrent mutation in human tumor samples. Our results suggest that MRAS mutation and IGF1R amplification could drive tumorigenesis of Type IV and could be new therapeutic targets. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Myb proteins: angels and demons in normal and transformed cells.

PubMed

Zhou, Ye; Ness, Scott A

2011-01-01

A key regulator of proliferation, differentiation and cell fate, the c-Myb transcription factor regulates the expression of hundreds of genes and is in turn regulated by numerous pathways and protein interactions. However, the most unique feature of c-Myb is that it can be converted into an oncogenic transforming protein through a few mutations that completely change its activity and specificity. The c-Myb protein is a myriad of interactions and activities rolled up in a protein that controls proliferation and differentiation in many different cell types. Here we discuss the background and recent progress that have led to a better understanding of this complex protein, and outline the questions that have yet to be answered.

Relationship of driver oncogenes to long term pemetrexed response in non-small cell lung cancer

PubMed Central

Liang, Ying; Wakelee, Heather A.; Neal, Joel W.

2015-01-01

Background Pemetrexed is approved in the treatment of advanced stage non-squamous non-small-cell lung cancer (NSCLC). The length of response is variable, and we thus sought to identify which clinicopathologic characteristics are associated with long term disease control with pemetrexed. Methods Patients with metastatic NSCLC were identified who received pemetrexed (with or without bevacizumab) for 12 months or longer, either as maintenance treatment after first-line platinum-based chemotherapy or as subsequent treatment. Clinical and pathological characteristics were collected. Results Of a total of 196 patients who received pemetrexed starting in 2007, 25 patients were identified who received pemetrexed for over one year. Of these, 15 patients received pemetrexed with or without bevacizumab as maintenance treatment and 10 patients received pemetrexed as subsequent treatment. Fifteen of the 25 patients (60%) had an oncogenic driver mutation as follows: five (20%) had ROS1 gene rearrangements, four (16%) had ALK gene rearrangements, three (12%) had KRAS mutations, two (8%) had epidermal growth factor receptor (EGFR) mutations, and one (4%) had an NRAS mutation. The median overall survival (OS) was 42.2 months (95% confidence interval [CI]: 37.4–61.3) and median progression free survival (PFS) was 22.1 months (95% CI: 15.1–29.1). Patients with an oncogenic driver mutation had significantly better PFS (p=0.006) and OS (p=0.001). Conclusions Among patients with NSCLC who received pemetrexed for an extended time, those with ALK and ROS1 gene rearrangements are proportionally overrepresented compared with that anticipated in a general non-squamous NSCLC population, and patients with oncogenic driver mutations had improved outcomes. PMID:25665893

Spliceosomal gene aberrations are rare, coexist with oncogenic mutations, and are unlikely to exert a driver effect in childhood MDS and JMML.

PubMed

Hirabayashi, Shinsuke; Flotho, Christian; Moetter, Jessica; Heuser, Michael; Hasle, Henrik; Gruhn, Bernd; Klingebiel, Thomas; Thol, Felicitas; Schlegelberger, Brigitte; Baumann, Irith; Strahm, Brigitte; Stary, Jan; Locatelli, Franco; Zecca, Marco; Bergstraesser, Eva; Dworzak, Michael; van den Heuvel-Eibrink, Marry M; De Moerloose, Barbara; Ogawa, Seishi; Niemeyer, Charlotte M; Wlodarski, Marcin W

2012-03-15

Somatic mutations of the spliceosomal machinery occur frequently in adult patients with myelodysplastic syndrome (MDS). We resequenced SF3B1, U2AF35, and SRSF2 in 371 children with MDS or juvenile myelomonocytic leukemia. We found missense mutations in 2 juvenile myelomonocytic leukemia cases and in 1 child with systemic mastocytosis with MDS. In 1 juvenile myelomonocytic leukemia patient, the SRSF2 mutation that initially coexisted with an oncogenic NRAS mutation was absent at relapse, whereas the NRAS mutation persisted and a second, concomitant NRAS mutation later emerged. The patient with systemic mastocytosis and MDS carried both mutated U2AF35 and KIT in a single clone as confirmed by clonal sequencing. In the adult MDS patients sequenced for control purposes, we detected previously reported mutations in 7/30 and a novel SRSF2 deletion (c.284_307del) in 3 of 30 patients. These findings implicate that spliceosome mutations are rare in pediatric MDS and juvenile myelomonocytic leukemia and are unlikely to operate as driver mutations.

Targeted nanoconjugate co-delivering siRNA and tyrosine kinase inhibitor to KRAS mutant NSCLC dissociates GAB1-SHP2 post oncogene knockdown

PubMed Central

Srikar, R.; Suresh, Dhananjay; Zambre, Ajit; Taylor, Kristen; Chapman, Sarah; Leevy, Matthew; Upendran, Anandhi; Kannan, Raghuraman

2016-01-01

A tri-block nanoparticle (TBN) comprising of an enzymatically cleavable porous gelatin nanocore encapsulated with gefitinib (tyrosine kinase inhibitor (TKI)) and surface functionalized with cetuximab-siRNA conjugate has been synthesized. Targeted delivery of siRNA to undruggable KRAS mutated non-small cell lung cancer cells would sensitize the cells to TKI drugs and offers an efficient therapy for treating cancer; however, efficient delivery of siRNA and releasing it in cytoplasm remains a major challenge. We have shown TBN can efficiently deliver siRNA to cytoplasm of KRAS mutant H23 Non-Small Cell Lung Cancer (NSCLC) cells for oncogene knockdown; subsequently, sensitizing it to TKI. In the absence of TKI, the nanoparticle showed minimal toxicity suggesting that the cells adapt a parallel GAB1 mediated survival pathway. In H23 cells, activated ERK results in phosphorylation of GAB1 on serine and threonine residues to form GAB1-p85 PI3K complex. In the absence of TKI, knocking down the oncogene dephosphorylated ERK, and negated the complex formation. This event led to tyrosine phosphorylation at Tyr627 domain of GAB1 that regulated EGFR signaling by recruiting SHP2. In the presence of TKI, GAB1-SHP2 dissociation occurs, leading to cell death. The outcome of this study provides a promising platform for treating NSCLC patients harboring KRAS mutation. PMID:27530552

A Review: Molecular Aberrations within Hippo Signaling in Bone and Soft-Tissue Sarcomas

PubMed Central

Deel, Michael D.; Li, Jenny J.; Crose, Lisa E. S.; Linardic, Corinne M.

2015-01-01

The Hippo signaling pathway is an evolutionarily conserved developmental network vital for the regulation of organ size, tissue homeostasis, repair and regeneration, and cell fate. The Hippo pathway has also been shown to have tumor suppressor properties. Hippo transduction involves a series of kinases and scaffolding proteins that are intricately connected to proteins in developmental cascades and in the tissue microenvironment. This network governs the downstream Hippo transcriptional co-activators, YAP and TAZ, which bind to and activate the output of TEADs, as well as other transcription factors responsible for cellular proliferation, self-renewal, differentiation, and survival. Surprisingly, there are few oncogenic mutations within the core components of the Hippo pathway. Instead, dysregulated Hippo signaling is a versatile accomplice to commonly mutated cancer pathways. For example, YAP and TAZ can be activated by oncogenic signaling from other pathways, or serve as co-activators for classical oncogenes. Emerging evidence suggests that Hippo signaling couples cell density and cytoskeletal structural changes to morphogenic signals and conveys a mesenchymal phenotype. While much of Hippo biology has been described in epithelial cell systems, it is clear that dysregulated Hippo signaling also contributes to malignancies of mesenchymal origin. This review will summarize the known molecular alterations within the Hippo pathway in sarcomas and highlight how several pharmacologic compounds have shown activity in modulating Hippo components, providing proof-of-principle that Hippo signaling may be harnessed for therapeutic application in sarcomas. PMID:26389076

A Review: Molecular Aberrations within Hippo Signaling in Bone and Soft-Tissue Sarcomas.

PubMed

Deel, Michael D; Li, Jenny J; Crose, Lisa E S; Linardic, Corinne M

2015-01-01

The Hippo signaling pathway is an evolutionarily conserved developmental network vital for the regulation of organ size, tissue homeostasis, repair and regeneration, and cell fate. The Hippo pathway has also been shown to have tumor suppressor properties. Hippo transduction involves a series of kinases and scaffolding proteins that are intricately connected to proteins in developmental cascades and in the tissue microenvironment. This network governs the downstream Hippo transcriptional co-activators, YAP and TAZ, which bind to and activate the output of TEADs, as well as other transcription factors responsible for cellular proliferation, self-renewal, differentiation, and survival. Surprisingly, there are few oncogenic mutations within the core components of the Hippo pathway. Instead, dysregulated Hippo signaling is a versatile accomplice to commonly mutated cancer pathways. For example, YAP and TAZ can be activated by oncogenic signaling from other pathways, or serve as co-activators for classical oncogenes. Emerging evidence suggests that Hippo signaling couples cell density and cytoskeletal structural changes to morphogenic signals and conveys a mesenchymal phenotype. While much of Hippo biology has been described in epithelial cell systems, it is clear that dysregulated Hippo signaling also contributes to malignancies of mesenchymal origin. This review will summarize the known molecular alterations within the Hippo pathway in sarcomas and highlight how several pharmacologic compounds have shown activity in modulating Hippo components, providing proof-of-principle that Hippo signaling may be harnessed for therapeutic application in sarcomas.

Presence of a consensus DNA motif at nearby DNA sequence of the mutation susceptible CG nucleotides.

PubMed

Chowdhury, Kaushik; Kumar, Suresh; Sharma, Tanu; Sharma, Ankit; Bhagat, Meenakshi; Kamai, Asangla; Ford, Bridget M; Asthana, Shailendra; Mandal, Chandi C

2018-01-10

Complexity in tissues affected by cancer arises from somatic mutations and epigenetic modifications in the genome. The mutation susceptible hotspots present within the genome indicate a non-random nature and/or a position specific selection of mutation. An association exists between the occurrence of mutations and epigenetic DNA methylation. This study is primarily aimed at determining mutation status, and identifying a signature for predicting mutation prone zones of tumor suppressor (TS) genes. Nearby sequences from the top five positions having a higher mutation frequency in each gene of 42 TS genes were selected from a cosmic database and were considered as mutation prone zones. The conserved motifs present in the mutation prone DNA fragments were identified. Molecular docking studies were done to determine putative interactions between the identified conserved motifs and enzyme methyltransferase DNMT1. Collective analysis of 42 TS genes found GC as the most commonly replaced and AT as the most commonly formed residues after mutation. Analysis of the top 5 mutated positions of each gene (210 DNA segments for 42 TS genes) identified that CG nucleotides of the amino acid codons (e.g., Arginine) are most susceptible to mutation, and found a consensus DNA "T/AGC/GAGGA/TG" sequence present in these mutation prone DNA segments. Similar to TS genes, analysis of 54 oncogenes not only found CG nucleotides of the amino acid Arg as the most susceptible to mutation, but also identified the presence of similar consensus DNA motifs in the mutation prone DNA fragments (270 DNA segments for 54 oncogenes) of oncogenes. Docking studies depicted that, upon binding of DNMT1 methylates to this consensus DNA motif (C residues of CpG islands), mutation was likely to occur. Thus, this study proposes that DNMT1 mediated methylation in chromosomal DNA may decrease if a foreign DNA segment containing this consensus sequence along with CG nucleotides is exogenously introduced to dividing cancer cells. Copyright © 2017 Elsevier B.V. All rights reserved.

The ortholog of the human proto-oncogene ROS1 is required for epithelial development in C. elegans

PubMed Central

Jones, Martin R; Rose, Ann M; Baillie, David L

2013-01-01

The orphan receptor ROS1 is a human proto-oncogene, mutations of which are found in an increasing number of cancers. Little is known about the role of ROS1, however in vertebrates it has been implicated in promoting differentiation programs in specialized epithelial tissues. In this study we show that the C. elegans ortholog of ROS1, the receptor tyrosine kinase ROL-3, has an essential role in orchestrating the morphogenesis and development of specialized epidermal tissues, highlighting a potentially conserved function in coordinating crosstalk between developing epithelial cells. We also provide evidence of a direct relationship between ROL-3, the mucin SRAP-1, and BCC-1, the homolog of mRNA regulating protein Bicaudal-C. This study answers a longstanding question as to the developmental function of ROL-3, identifies three new genes that are expressed and function in the developing epithelium of C. elegans, and introduces the nematode as a potentially powerful model system for investigating the increasingly important, yet poorly understood, human oncogene ROS1. genesis 51:545–561. PMID:23733356

In situ mutation detection and visualization of intratumor heterogeneity for cancer research and diagnostics

PubMed Central

Grundberg, Ida; Kiflemariam, Sara; Mignardi, Marco; Imgenberg-Kreuz, Juliana; Edlund, Karolina; Micke, Patrick; Sundström, Magnus; Sjöblom, Tobias

2013-01-01

Current assays for somatic mutation analysis are based on extracts from tissue sections that often contain morphologically heterogeneous neoplastic regions with variable contents of genetically normal stromal and inflammatory cells, obscuring the results of the assays. We have developed an RNA-based in situ mutation assay that targets oncogenic mutations in a multiplex fashion that resolves the heterogeneity of the tissue sample. Activating oncogenic mutations are targets for a new generation of cancer drugs. For anti-EGFR therapy prediction, we demonstrate reliable in situ detection of KRAS mutations in codon 12 and 13 in colon and lung cancers in three different types of routinely processed tissue materials. High-throughput screening of KRAS mutation status was successfully performed on a tissue microarray. Moreover, we show how the patterns of expressed mutated and wild-type alleles can be studied in situ in tumors with complex combinations of mutated EGFR, KRAS and TP53. This in situ method holds great promise as a tool to investigate the role of somatic mutations during tumor progression and for prediction of response to targeted therapy. PMID:24280411

Transforming activity and therapeutic targeting of C-terminal-binding protein 2 in Apc-mutated neoplasia.

PubMed

Sumner, E T; Chawla, A T; Cororaton, A D; Koblinski, J E; Kovi, R C; Love, I M; Szomju, B B; Korwar, S; Ellis, K C; Grossman, S R

2017-08-17

Overexpression of the transcriptional coregulators C-terminal binding proteins 1 and 2 (CtBP1 and 2) occurs in many human solid tumors and is associated with poor prognosis. CtBP modulates oncogenic gene expression programs and is an emerging drug target, but its oncogenic role is unclear. Consistent with this oncogenic potential, exogenous CtBP2 transformed primary mouse and human cells to anchorage independence similarly to mutant H-Ras. To investigate CtBP's contribution to in vivo tumorigenesis, Apc min/+ mice, which succumb to massive intestinal polyposis, were bred to Ctbp2 +/- mice. CtBP interacts with adenomatous polyposis coli (APC) protein, and is stabilized in both APC-mutated human colon cancers and Apc min/+ intestinal polyps. Ctbp2 heterozygosity increased the median survival of Apc min/+ mice from 21 to 48 weeks, and reduced polyp formation by 90%, with Ctbp2 +/- polyps exhibiting reduced levels of β-catenin and its oncogenic transcriptional target, cyclin D1. CtBP's potential as a therapeutic target was studied by treating Apc min/+ mice with the CtBP small-molecule inhibitors 4-methylthio-2-oxobutyric acid and 2-hydroxy-imino phenylpyruvic acid, both of which reduced polyposis by more than half compared with vehicle treatment. Phenocopying Ctbp2 deletion, both Ctbp inhibitors caused substantial decreases in the protein level of Ctbp2, as well its oncogenic partner β-catenin, and the effects of the inhibitors on CtBP and β-catenin levels could be modeled in an APC-mutated human colon cancer cell line. CtBP2 is thus a druggable transforming oncoprotein critical for the evolution of neoplasia driven by Apc mutation.

A Novel Ras Effector Pathway Found to Play Significant Role in Tumor Suppression | Poster

Cancer.gov

By Nancy Parrish, Staff Writer; photo by Richard Frederickson, Staff Photographer Normal cells have mechanisms to prevent the development of cancer. Among these is a type of tumor suppressor mechanism known as oncogene-induced senescence, or OIS, which halts the uncontrolled growth of cells caused by mutations in oncogenes. The oncogene Ras plays a crucial role in inducing OIS

P53 Mutation Profiles in Premenopausal Versus Postmenopausal Breast Cancer in a Stationary Population

DTIC Science & Technology

1997-08-01

Gryka , M ., Bischoff, F Z., Tainsky, M . A., Friend. S. H., 1990: Germ line p53 mutation in a familial syndrome of breast cancer, sarcomas, and...of relapse and survival with amplification of the HER-2/neu oncogene. Science 235:177-182 2. Prosser, J., Thompson, A. M ., Cranston, G and Evans, HJ...1990: Evidence that p53 behaves as a tumor suppressor gene in sporadic breast tumours. Oncogene 5:1573-1579. 3. Davidoff, A. M ., Kerns, B.J. M

The Structural Basis of Oncogenic Mutations G12, G13 and Q61 in Small GTPase K-Ras4B

NASA Astrophysics Data System (ADS)

Lu, Shaoyong; Jang, Hyunbum; Nussinov, Ruth; Zhang, Jian

2016-02-01

Ras mediates cell proliferation, survival and differentiation. Mutations in K-Ras4B are predominant at residues G12, G13 and Q61. Even though all impair GAP-assisted GTP → GDP hydrolysis, the mutation frequencies of K-Ras4B in human cancers vary. Here we aim to figure out their mechanisms and differential oncogenicity. In total, we performed 6.4 μs molecular dynamics simulations on the wild-type K-Ras4B (K-Ras4BWT-GTP/GDP) catalytic domain, the K-Ras4BWT-GTP-GAP complex, and the mutants (K-Ras4BG12C/G12D/G12V-GTP/GDP, K-Ras4BG13D-GTP/GDP, K-Ras4BQ61H-GTP/GDP) and their complexes with GAP. In addition, we simulated ‘exchanged’ nucleotide states. These comprehensive simulations reveal that in solution K-Ras4BWT-GTP exists in two, active and inactive, conformations. Oncogenic mutations differentially elicit an inactive-to-active conformational transition in K-Ras4B-GTP; in K-Ras4BG12C/G12D-GDP they expose the bound nucleotide which facilitates the GDP-to-GTP exchange. These mechanisms may help elucidate the differential mutational statistics in K-Ras4B-driven cancers. Exchanged nucleotide simulations reveal that the conformational transition is more accessible in the GTP-to-GDP than in the GDP-to-GTP exchange. Importantly, GAP not only donates its R789 arginine finger, but stabilizes the catalytically-competent conformation and pre-organizes catalytic residue Q61; mutations disturb the R789/Q61 organization, impairing GAP-mediated GTP hydrolysis. Together, our simulations help provide a mechanistic explanation of key mutational events in one of the most oncogenic proteins in cancer.

Oncogenic PIK3CA gene mutations and HER2/neu gene amplifications determine the sensitivity of uterine serous carcinoma cell lines to GDC-0980, a selective inhibitor of Class I PI3 kinase and mTOR kinase (TORC1/2).

PubMed

English, Diana P; Bellone, Stefania; Cocco, Emiliano; Bortolomai, Ileana; Pecorelli, Sergio; Lopez, Salvatore; Silasi, Dan-Arin; Schwartz, Peter E; Rutherford, Thomas; Santin, Alessandro D

2013-11-01

To evaluate PIK3CA mutational status and c-erbB2 gene amplification in a series of primary uterine serous carcinomas (USC) cell lines. To assess the efficacy of GDC-0980, a potent inhibitor of Class I PI3 kinase and mTOR kinase (TORC1/2), against primary USC harboring HER2/neu gene amplification and/or PIK3CA mutations. Twenty-two primary USC cell lines were evaluated for c-erbB2 oncogene amplification by fluorescence in situ hybridization (FISH) assays and for PIK3CA gene mutations by direct DNA sequencing of exons 9 and 20. In vitro sensitivity to GDC-0980 was evaluated by flow-cytometry-based viability and proliferation assays. Downstream cellular responses to GDC-0980 were assessed by measuring phosphorylation of the 4-EBP1 protein by flow-cytometry. Five of 22 (22.7%) USC cell lines contained oncogenic PIK3CA mutations although 9 (40.9%) harbored c-erbB2 gene amplification by FISH. GDC-0980 caused a strong differential growth inhibition in FISH+ USC when compared with FISH- (GDC-0980 IC50 mean ± SEM = 0.29 ± 0.05 μM in FISH+ vs 1.09 ± 0.20 μM in FISH- tumors, P = .02). FISH+ USC harboring PIK3CA mutations were significantly more sensitive to GDC-0980 exposure when compared with USC cell lines harboring wild-type PIK3CA (P = .03). GDC-0980 growth-inhibition was associated with a significant and dose-dependent decline in phosphorylated 4-EBP1 levels. Oncogenic PIK3CA mutations and c-erbB2 gene amplification may represent biomarkers to identify patients harboring USC who may benefit most from the use of GDC-0980. Copyright © 2013 Mosby, Inc. All rights reserved.

Mutant JAK3 phosphoproteomic profiling predicts synergism between JAK3 inhibitors and MEK/BCL2 inhibitors for the treatment of T-cell acute lymphoblastic leukemia

PubMed Central

Degryse, S; de Bock, C E; Demeyer, S; Govaerts, I; Bornschein, S; Verbeke, D; Jacobs, K; Binos, S; Skerrett-Byrne, D A; Murray, H C; Verrills, N M; Van Vlierberghe, P; Cools, J; Dun, M D

2018-01-01

Mutations in the interleukin-7 receptor (IL7R) or the Janus kinase 3 (JAK3) kinase occur frequently in T-cell acute lymphoblastic leukemia (T-ALL) and both are able to drive cellular transformation and the development of T-ALL in mouse models. However, the signal transduction pathways downstream of JAK3 mutations remain poorly characterized. Here we describe the phosphoproteome downstream of the JAK3(L857Q)/(M511I) activating mutations in transformed Ba/F3 lymphocyte cells. Signaling pathways regulated by JAK3 mutants were assessed following acute inhibition of JAK1/JAK3 using the JAK kinase inhibitors ruxolitinib or tofacitinib. Comprehensive network interrogation using the phosphoproteomic signatures identified significant changes in pathways regulating cell cycle, translation initiation, mitogen-activated protein kinase and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/AKT signaling, RNA metabolism, as well as epigenetic and apoptotic processes. Key regulatory proteins within pathways that showed altered phosphorylation following JAK inhibition were targeted using selumetinib and trametinib (MEK), buparlisib (PI3K) and ABT-199 (BCL2), and found to be synergistic in combination with JAK kinase inhibitors in primary T-ALL samples harboring JAK3 mutations. These data provide the first detailed molecular characterization of the downstream signaling pathways regulated by JAK3 mutations and provide further understanding into the oncogenic processes regulated by constitutive kinase activation aiding in the development of improved combinatorial treatment regimens. PMID:28852199

Spectrum of oncogenic driver mutations in lung adenocarcinomas from East Asian never smokers.

PubMed

Li, Chenguang; Fang, Rong; Sun, Yihua; Han, Xiangkun; Li, Fei; Gao, Bin; Iafrate, A John; Liu, Xin-Yuan; Pao, William; Chen, Haiquan; Ji, Hongbin

2011-01-01

We previously showed that 90% (47 of 52; 95% CI, 0.79 to 0.96) of lung adenocarcinomas from East Asian never-smokers harbored well-known oncogenic mutations in just four genes: EGFR, HER2, ALK, and KRAS. Here, we sought to extend these findings to more samples and identify driver alterations in tumors negative for these mutations. We have collected and analyzed 202 resected lung adenocarcinomas from never smokers seen at Fudan University Shanghai Cancer Center. Since mutations were mutually exclusive in the first 52 examined, we determined the status of EGFR, KRAS, HER2, ALK, and BRAF in stepwise fashion as previously described. Samples negative for mutations in these 5 genes were subsequently examined for known ROS1 fusions by RT-PCR and direct sequencing. 152 tumors (75.3%) harbored EGFR mutations, 12 (6%) had HER2 mutations, 10 (5%) had ALK fusions all involving EML4 as the 5' partner, 4 (2%) had KRAS mutations, and 2 (1%) harbored ROS1 fusions. No BRAF mutation were detected. The vast majority (176 of 202; 87.1%, 95% CI: 0.82 to 0.91) of lung adenocarcinomas from never smokers harbor mutant kinases sensitive to available TKIs. Interestingly, patients with EGFR mutant patients tend to be older than those without EGFR mutations (58.3 Vs 54.3, P = 0.016) and patient without any known oncogenic driver tend to be diagnosed at a younger age (52.3 Vs 57.9, P = 0.013). Collectively, these data indicate that the majority of never smokers with lung adenocarcinoma could benefit from treatment with a specific tyrosine kinase inhibitor.

Spectrum of Oncogenic Driver Mutations in Lung Adenocarcinomas from East Asian Never Smokers

PubMed Central

Han, Xiangkun; Li, Fei; Gao, Bin; Iafrate, A. John; Liu, Xin-Yuan; Pao, William; Chen, Haiquan; Ji, Hongbin

2011-01-01

Purpose We previously showed that 90% (47 of 52; 95% CI, 0.79 to 0.96) of lung adenocarcinomas from East Asian never-smokers harbored well-known oncogenic mutations in just four genes: EGFR, HER2, ALK, and KRAS. Here, we sought to extend these findings to more samples and identify driver alterations in tumors negative for these mutations. Experimental Design We have collected and analyzed 202 resected lung adenocarcinomas from never smokers seen at Fudan University Shanghai Cancer Center. Since mutations were mutually exclusive in the first 52 examined, we determined the status of EGFR, KRAS, HER2, ALK, and BRAF in stepwise fashion as previously described. Samples negative for mutations in these 5 genes were subsequently examined for known ROS1 fusions by RT-PCR and direct sequencing. Results 152 tumors (75.3%) harbored EGFR mutations, 12 (6%) had HER2 mutations, 10 (5%) had ALK fusions all involving EML4 as the 5′ partner, 4 (2%) had KRAS mutations, and 2 (1%) harbored ROS1 fusions. No BRAF mutation were detected. Conclusion The vast majority (176 of 202; 87.1%, 95% CI: 0.82 to 0.91) of lung adenocarcinomas from never smokers harbor mutant kinases sensitive to available TKIs. Interestingly, patients with EGFR mutant patients tend to be older than those without EGFR mutations (58.3 Vs 54.3, P = 0.016) and patient without any known oncogenic driver tend to be diagnosed at a younger age (52.3 Vs 57.9, P = 0.013). Collectively, these data indicate that the majority of never smokers with lung adenocarcinoma could benefit from treatment with a specific tyrosine kinase inhibitor. PMID:22140546

Deleterious CHEK2 1100delC and L303X mutants identified among 38 human breast cancer cell lines.

PubMed

Wasielewski, Marijke; Hanifi-Moghaddam, Pejman; Hollestelle, Antoinette; Merajver, Sofia D; van den Ouweland, Ans; Klijn, Jan G M; Ethier, Stephen P; Schutte, Mieke

2009-01-01

The CHEK2 protein plays a major role in the regulation of DNA damage response pathways. Mutations in the CHEK2 gene, in particular 1100delC, have been associated with increased cancer risks, but the precise function of CHEK2 mutations in carcinogenesis is not known. Human cancer cell lines with CHEK2 mutations are therefore of main interest. Here, we have sequenced 38 breast cancer cell lines for mutations in the CHEK2 gene and identified two cell lines with deleterious CHEK2 mutations. Cell line UACC812 has a nonsense truncating mutation in the CHEK2 kinase domain (L303X) and cell line SUM102PT has the well-known oncogenic CHEK2 1100delC founder mutation. Immunohistochemical analysis revealed that the two CHEK2 mutant cell lines expressed neither CHEK2 nor P-Thr(68) CHEK2 proteins, implying abrogation of normal CHEK2 DNA repair functions. Cell lines UACC812 and SUM102PT thus are the first human CHEK2 null cell lines reported and should therefore be a major help in further unraveling the function of CHEK2 mutations in carcinogenesis.

Noncoding somatic and inherited single-nucleotide variants converge to promote ESR1 expression in breast cancer

PubMed Central

Bailey, Swneke D.; Desai, Kinjal; Kron, Ken J.; Mazrooei, Parisa; Sinnott-Armstrong, Nicholas A.; Treloar, Aislinn E.; Dowar, Mark; Thu, Kelsie L.; Cescon, David W.; Silvester, Jennifer; Yang, S. Y. Cindy; Wu, Xue; Pezo, Rossanna C.; Haibe-Kains, Benjamin; Mak, Tak W.; Bedard, Philippe L.; Pugh, Trevor J.; Sallari, Richard C.; Lupien, Mathieu

2016-01-01

Sustained expression of the oestrogen receptor alpha (ESR1) drives two-thirds of breast cancer and defines the ESR1-positive subtype. ESR1 engages enhancers upon oestrogen stimulation to establish an oncogenic expression program1. Somatic copy number alterations involving the ESR1 gene occur in approximately 1% of ESR1-positive breast cancers2–5, implying that other mechanisms underlie the persistent expression of ESR1. We report the significant enrichment of somatic mutations within the set of regulatory elements (SRE) regulating ESR1 in 7% of ESR1-positive breast cancers. These mutations regulate ESR1 expression by modulating transcription factor binding to the DNA. The SRE includes a recurrently mutated enhancer whose activity is also affected by a functional inherited single nucleotide variant (SNV) rs9383590 that accounts for several breast cancer risk-loci. Our work highlights the importance of considering the combinatorial activity of regulatory elements as a single unit to delineate the impact of noncoding genetic alterations on single genes in cancer. PMID:27571262

Nitrative and oxidative DNA damage caused by K-ras mutation in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohnishi, Shiho; Saito, Hiromitsu; Suzuki, Noboru

2011-09-23

Highlights: {yields} Mutated K-ras in transgenic mice caused nitrative DNA damage, 8-nitroguanine. {yields} The mutagenic 8-nitroguanine seemed to be generated by iNOS via Ras-MAPK signal. {yields} Mutated K-ras produces additional mutagenic lesions, as a new oncogenic role. -- Abstract: Ras mutation is important for carcinogenesis. Carcinogenesis consists of multi-step process with mutations in several genes. We investigated the role of DNA damage in carcinogenesis initiated by K-ras mutation, using conditional transgenic mice. Immunohistochemical analysis revealed that mutagenic 8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) were apparently formed in adenocarcinoma caused by mutated K-ras. 8-Nitroguanine was co-localized with iNOS, eNOS, NF-{kappa}B, IKK, MAPK, MEK,more » and mutated K-ras, suggesting that oncogenic K-ras causes additional DNA damage via signaling pathway involving these molecules. It is noteworthy that K-ras mutation mediates not only cell over-proliferation but also the accumulation of mutagenic DNA lesions, leading to carcinogenesis.« less

Small G proteins Rac1 and Ras regulate serine/threonine protein phosphatase 5 (PP5)·extracellular signal-regulated kinase (ERK) complexes involved in the feedback regulation of Raf1.

PubMed

Mazalouskas, Matthew D; Godoy-Ruiz, Raquel; Weber, David J; Zimmer, Danna B; Honkanen, Richard E; Wadzinski, Brian E

2014-02-14

Serine/threonine protein phosphatase 5 (PP5, PPP5C) is known to interact with the chaperonin heat shock protein 90 (HSP90) and is involved in the regulation of multiple cellular signaling cascades that control diverse cellular processes, such as cell growth, differentiation, proliferation, motility, and apoptosis. Here, we identify PP5 in stable complexes with extracellular signal-regulated kinases (ERKs). Studies using mutant proteins reveal that the formation of PP5·ERK1 and PP5·ERK2 complexes partially depends on HSP90 binding to PP5 but does not require PP5 or ERK1/2 activity. However, PP5 and ERK activity regulates the phosphorylation state of Raf1 kinase, an upstream activator of ERK signaling. Whereas expression of constitutively active Rac1 promotes the assembly of PP5·ERK1/2 complexes, acute activation of ERK1/2 fails to influence the phosphatase-kinase interaction. Introduction of oncogenic HRas (HRas(V12)) has no effect on PP5-ERK1 binding but selectively decreases the interaction of PP5 with ERK2, in a manner that is independent of PP5 and MAPK/ERK kinase (MEK) activity, yet paradoxically requires ERK2 activity. Additional studies conducted with oncogenic variants of KRas4B reveal that KRas(L61), but not KRas(V12), also decreases the PP5-ERK2 interaction. The expression of wild type HRas or KRas proteins fails to reduce PP5-ERK2 binding, indicating that the effect is specific to HRas(V12) and KRas(L61) gain-of-function mutations. These findings reveal a novel, differential responsiveness of PP5-ERK1 and PP5-ERK2 interactions to select oncogenic Ras variants and also support a role for PP5·ERK complexes in regulating the feedback phosphorylation of PP5-associated Raf1.

Identification of Novel Ovarian Cancer Oncogenes that Function by Regulating Exosome Function

DTIC Science & Technology

2017-09-01

Novel Ovarian Cancer Oncogenes that Function by Regulating Exosome Function September 2017 x 1Sep2016...31Aug2017 Email: mbirrer@partners.org 6 Identification of Novel Ovarian Cancer Oncogenes that Function by Regulating Exosome Function xx

Differences in somatic mutation landscape of hepatocellular carcinoma in Asian American and European American populations

PubMed Central

Hu, Qiang; Yan, Li; Liu, Biao; Ambrosone, Christine B.; Wang, Jianmin; Liu, Song

2016-01-01

The incidence rate of hepatocellular carcinoma (HCC) is higher in populations of Asian ancestry than European ancestry (EA). We sought to investigate HCC mutational differences between the two populations, which may reflect differences in the prevalence of etiological factors. We compared HCC somatic mutations in patients of self-reported Asian American and EA from The Cancer Genome Atlas (TCGA), and assessed associations of tumor mutations with established HCC risk factors. Although the average mutation burden was similar, TP53 and RB1 were mutated at a much higher frequency in Asian Americans than in EAs (TP53: 43% vs. 21%; RB1: 19% vs. 2%). Three putative oncogenic genes, including TRPM3, SAGE1, and ADAMTS7, were mutated exclusively in Asians. In addition, VEGF binding pathway, a druggable target by tyrosine kinase inhibitors such as sorafenib, was mutated at a higher frequency among Asians (13% vs. 2%); while the negative regulation of IL17 production, involved in inflammation and autoimmunity, was mutated only in EAs (12% vs. 0). Accounting for HCC risk factors had little impact on any of the mutational differences. In conclusion, we demonstrated here mutational differences in important cancer genes and pathways between Asian and European ancestries. These differences may have implications for the prevention and treatment of HCC. PMID:27246981

Differences in somatic mutation landscape of hepatocellular carcinoma in Asian American and European American populations.

PubMed

Yao, Song; Johnson, Christopher; Hu, Qiang; Yan, Li; Liu, Biao; Ambrosone, Christine B; Wang, Jianmin; Liu, Song

2016-06-28

The incidence rate of hepatocellular carcinoma (HCC) is higher in populations of Asian ancestry than European ancestry (EA). We sought to investigate HCC mutational differences between the two populations, which may reflect differences in the prevalence of etiological factors. We compared HCC somatic mutations in patients of self-reported Asian American and EA from The Cancer Genome Atlas (TCGA), and assessed associations of tumor mutations with established HCC risk factors. Although the average mutation burden was similar, TP53 and RB1 were mutated at a much higher frequency in Asian Americans than in EAs (TP53: 43% vs. 21%; RB1: 19% vs. 2%). Three putative oncogenic genes, including TRPM3, SAGE1, and ADAMTS7, were mutated exclusively in Asians. In addition, VEGF binding pathway, a druggable target by tyrosine kinase inhibitors such as sorafenib, was mutated at a higher frequency among Asians (13% vs. 2%); while the negative regulation of IL17 production, involved in inflammation and autoimmunity, was mutated only in EAs (12% vs. 0). Accounting for HCC risk factors had little impact on any of the mutational differences. In conclusion, we demonstrated here mutational differences in important cancer genes and pathways between Asian and European ancestries. These differences may have implications for the prevention and treatment of HCC.

Cellular context-dependent consequences of Apc mutations on gene regulation and cellular behavior.

PubMed

Hashimoto, Kyoichi; Yamada, Yosuke; Semi, Katsunori; Yagi, Masaki; Tanaka, Akito; Itakura, Fumiaki; Aoki, Hitomi; Kunisada, Takahiro; Woltjen, Knut; Haga, Hironori; Sakai, Yoshiharu; Yamamoto, Takuya; Yamada, Yasuhiro

2017-01-24

The spectrum of genetic mutations differs among cancers in different organs, implying a cellular context-dependent effect for genetic aberrations. However, the extent to which the cellular context affects the consequences of oncogenic mutations remains to be fully elucidated. We reprogrammed colon tumor cells in an Apc Min/+ (adenomatous polyposis coli) mouse model, in which the loss of the Apc gene plays a critical role in tumor development and subsequently, established reprogrammed tumor cells (RTCs) that exhibit pluripotent stem cell (PSC)-like signatures of gene expression. We show that the majority of the genes in RTCs that were affected by Apc mutations did not overlap with the genes affected in the intestine. RTCs lacked pluripotency but exhibited an increased expression of Cdx2 and a differentiation propensity that was biased toward the trophectoderm cell lineage. Genetic rescue of the mutated Apc allele conferred pluripotency on RTCs and enabled their differentiation into various cell types in vivo. The redisruption of Apc in RTC-derived differentiated cells resulted in neoplastic growth that was exclusive to the intestine, but the majority of the intestinal lesions remained as pretumoral microadenomas. These results highlight the significant influence of cellular context on gene regulation, cellular plasticity, and cellular behavior in response to the loss of the Apc function. Our results also imply that the transition from microadenomas to macroscopic tumors is reprogrammable, which underscores the importance of epigenetic regulation on tumor promotion.

Cellular context-dependent consequences of Apc mutations on gene regulation and cellular behavior

PubMed Central

Hashimoto, Kyoichi; Yamada, Yosuke; Semi, Katsunori; Yagi, Masaki; Tanaka, Akito; Itakura, Fumiaki; Aoki, Hitomi; Kunisada, Takahiro; Woltjen, Knut; Haga, Hironori; Sakai, Yoshiharu; Yamamoto, Takuya; Yamada, Yasuhiro

2017-01-01

The spectrum of genetic mutations differs among cancers in different organs, implying a cellular context-dependent effect for genetic aberrations. However, the extent to which the cellular context affects the consequences of oncogenic mutations remains to be fully elucidated. We reprogrammed colon tumor cells in an ApcMin/+ (adenomatous polyposis coli) mouse model, in which the loss of the Apc gene plays a critical role in tumor development and subsequently, established reprogrammed tumor cells (RTCs) that exhibit pluripotent stem cell (PSC)-like signatures of gene expression. We show that the majority of the genes in RTCs that were affected by Apc mutations did not overlap with the genes affected in the intestine. RTCs lacked pluripotency but exhibited an increased expression of Cdx2 and a differentiation propensity that was biased toward the trophectoderm cell lineage. Genetic rescue of the mutated Apc allele conferred pluripotency on RTCs and enabled their differentiation into various cell types in vivo. The redisruption of Apc in RTC-derived differentiated cells resulted in neoplastic growth that was exclusive to the intestine, but the majority of the intestinal lesions remained as pretumoral microadenomas. These results highlight the significant influence of cellular context on gene regulation, cellular plasticity, and cellular behavior in response to the loss of the Apc function. Our results also imply that the transition from microadenomas to macroscopic tumors is reprogrammable, which underscores the importance of epigenetic regulation on tumor promotion. PMID:28057861

A study of therapy targeted EGFR/ALK mutations in Indian patients with lung adenocarcinoma: A clinical and epidemiological study.

PubMed

Rana, Vandana; Ranjan, Praveer; Jagani, Rajat; Rathi, K R; Kumar, Dharmesh; Khera, Anurag

2018-04-01

Established predictive biomarkers for Non-Small Cell Lung Carcinoma (NSCLC) include sensitizing Epidermal Growth Factor Receptor (EGFR) mutations and Anaplastic Lymphoma Kinase (ALK) fusion oncogene. The primary aim of the study is to ascertain the prevalence of EGFR mutation and ALK gene rearrangement in patients of lung adenocarcinoma in Indian population and the second objective is to impress upon the importance of adequate processing of limited tissue samples. Histopathologically confirmed cases of lung adenocarcinoma, whose tumour had been tested for both EGFR and ALK gene mutations, were included in this study. The EGFR mutations were analyzed using PCR and Gene Sequencing. ALK fusion oncogene was found by Fluorescence In Situ Hybridization (FISH) technique using kit of Vysis LSI ALK Dual colour Break Apart Rearrangement probe. A total of 152 cases of lung adenocarcinoma were included. Out of which, 92 (60.5%) were male and 60 (39.5%) were female. After exclusion of 17 cases due to unsatisfactory result, EGFR mutations were found positive in 35.5% cases (48/135). ALK gene rearrangement was found in 7.6% (10/131) after excluding 21 cases with unsatisfactory result. EGFR mutations and ALK gene rearrangement was found to be mutually exclusive. Incidence of EGFR mutations (35.5%) is much higher in Indian population than in Caucasians (13%) and is close to the incidence in East Asian countries. The 7.6% incidence of ALK fusion oncogene in Indian patients establishes the importance of molecular studies to give maximum benefit of targeted therapy to the patients.

Declining lymphoid progenitor fitness promotes aging-associated leukemogenesis.

PubMed

Henry, Curtis J; Marusyk, Andriy; Zaberezhnyy, Vadym; Adane, Biniam; DeGregori, James

2010-12-14

Aging is associated with the functional decline of cells, tissues, and organs. At the same time, age is the single most important prognostic factor in the development of most human cancers, including chronic myelogenous and acute lymphoblastic leukemias initiated by Bcr-Abl oncogenic translocations. Prevailing paradigms attribute the association between aging and cancers to the accumulation of oncogenic mutations over time, because the accrual of oncogenic events is thought to be the rate-limiting step in initiation and progression of cancers. Conversely, aging-associated functional decline caused by both cell-autonomous and non-cell-autonomous mechanisms is likely to reduce the fitness of stem and progenitor cell populations. This reduction in fitness should be conducive for increased selection of oncogenic mutations that can at least partially alleviate fitness defects, thereby promoting the initiation of cancers. We tested this hypothesis using mouse hematopoietic models. Our studies indicate that the dramatic decline in the fitness of aged B-lymphopoiesis coincides with altered receptor-associated kinase signaling. We further show that Bcr-Abl provides a much greater competitive advantage to old B-lymphoid progenitors compared with young progenitors, coinciding with restored kinase signaling pathways, and that this enhanced competitive advantage translates into increased promotion of Bcr-Abl-driven leukemias. Moreover, impairing IL-7-mediated signaling is sufficient to promote selection for Bcr-Abl-expressing B progenitors. These studies support an unappreciated causative link between aging and cancer: increased selection of oncogenic mutations as a result of age-dependent alterations of the fitness landscape.

Intrinsic and Extrinsic Regulation of PD-L2 Expression in Oncogene-Driven Non-Small Cell Lung Cancer.

PubMed

Shibahara, Daisuke; Tanaka, Kentaro; Iwama, Eiji; Kubo, Naoki; Ota, Keiichi; Azuma, Koichi; Harada, Taishi; Fujita, Jiro; Nakanishi, Yoichi; Okamoto, Isamu

2018-03-27

The interaction of programmed cell death ligand 2 (PD-L2) with programmed cell death 1 is implicated in tumor immune escape. The regulation of PD-L2 expression in tumor cells has remained unclear, however. We here examined intrinsic and extrinsic regulation of PD-L2 expression in NSCLC. PD-L2 expression was evaluated by reverse transcription and real-time polymerase chain reaction analysis and by flow cytometry. BEAS-2B cells stably expressing an activated mutant form of EGFR or the echinoderm microtubule associated protein like 4 (EML4)-ALK receptor tyrosine kinase fusion oncoprotein manifested increased expression of PD-L2 at both the mRNA and protein levels. Furthermore, treatment of NSCLC cell lines that harbor such driver oncogenes with corresponding EGFR or ALK tyrosine kinase inhibitors or depletion of EGFR or ALK by small interfering RNA transfection suppressed expression of PD-L2, demonstrating that activating EGFR mutations or echinoderm microtubule associated protein like 4 gene (EML4)-ALK receptor tyrosine kinase gene (ALK) fusion intrinsically induce PD-L2 expression. We also found that interferon gamma (IFN-γ) extrinsically induced expression of PD-L2 through signal transducer and activator of transcription 1 signaling in NSCLC cells. Oncogene-driven expression of PD-L2 in NSCLC cells was inhibited by knockdown of the transcription factors signal transducer and activator of transcription 3 (STAT3) or c-FOS. IFN-γ also activated STAT3 and c-FOS, suggesting that these proteins may also contribute to the extrinsic induction of PD-L2 expression. Expression of PD-L2 is induced intrinsically by activating EGFR mutations or EML4-ALK fusion and extrinsically by IFN-γ, with STAT3 and c-FOS possibly contributing to both intrinsic and extrinsic pathways. Our results thus provide insight into the complexity of tumor immune escape in NSCLC. Copyright © 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Mitogen-Inducible Gene-6 Mediates Feedback Inhibition from Mutated BRAF towards the Epidermal Growth Factor Receptor and Thereby Limits Malignant Transformation

PubMed Central

Milewska, Malgorzata; Romano, David; Herrero, Ana; Guerriero, Maria Luisa; Birtwistle, Marc; Quehenberger, Franz; Hatzl, Stefan; Kholodenko, Boris N.; Segatto, Oreste; Kolch, Walter; Zebisch, Armin

2015-01-01

BRAF functions in the RAS-extracellular signal-regulated kinase (ERK) signaling cascade. Activation of this pathway is necessary to mediate the transforming potential of oncogenic BRAF, however, it may also cause a negative feedback that inhibits the epidermal growth factor receptor (EGFR). Mitogen-inducible gene-6 (MIG-6) is a potent inhibitor of the EGFR and has been demonstrated to function as a tumor suppressor. As MIG-6 can be induced via RAS-ERK signaling, we investigated its potential involvement in this negative regulatory loop. Focus formation assays were performed and demonstrated that MIG-6 significantly reduces malignant transformation induced by oncogenic BRAF. Although this genetic interaction was mirrored by a physical interaction between MIG-6 and BRAF, we did not observe a direct regulation of BRAF kinase activity by MIG-6. Interestingly, a selective chemical EGFR inhibitor suppressed transformation to a similar degree as MIG-6, whereas combining these approaches had no synergistic effect. By analyzing a range of BRAF mutated and wildtype cell line models, we could show that BRAF V600E causes a strong upregulation of MIG-6, which was mediated at the transcriptional level via the RAS-ERK pathway and resulted in downregulation of EGFR activation. This feedback loop is operational in tumors, as shown by the analysis of almost 400 patients with papillary thyroid cancer (PTC). Presence of BRAF V600E correlated with increased MIG-6 expression on the one hand, and with inactivation of the EGFR and of PI3K/AKT signaling on the other hand. Importantly, we also observed a more aggressive disease phenotype when BRAF V600E coexisted with low MIG-6 expression. Finally, analysis of methylation data was performed and revealed that higher methylation of MIG-6 correlated to its decreased expression. Taken together, we demonstrate that MIG-6 efficiently reduces cellular transformation driven by oncogenic BRAF by orchestrating a negative feedback circuit directed towards the EGFR. PMID:26065894

Identification of druggable cancer driver genes amplified across TCGA datasets.

PubMed

Chen, Ying; McGee, Jeremy; Chen, Xianming; Doman, Thompson N; Gong, Xueqian; Zhang, Youyan; Hamm, Nicole; Ma, Xiwen; Higgs, Richard E; Bhagwat, Shripad V; Buchanan, Sean; Peng, Sheng-Bin; Staschke, Kirk A; Yadav, Vipin; Yue, Yong; Kouros-Mehr, Hosein

2014-01-01

The Cancer Genome Atlas (TCGA) projects have advanced our understanding of the driver mutations, genetic backgrounds, and key pathways activated across cancer types. Analysis of TCGA datasets have mostly focused on somatic mutations and translocations, with less emphasis placed on gene amplifications. Here we describe a bioinformatics screening strategy to identify putative cancer driver genes amplified across TCGA datasets. We carried out GISTIC2 analysis of TCGA datasets spanning 16 cancer subtypes and identified 486 genes that were amplified in two or more datasets. The list was narrowed to 75 cancer-associated genes with potential "druggable" properties. The majority of the genes were localized to 14 amplicons spread across the genome. To identify potential cancer driver genes, we analyzed gene copy number and mRNA expression data from individual patient samples and identified 42 putative cancer driver genes linked to diverse oncogenic processes. Oncogenic activity was further validated by siRNA/shRNA knockdown and by referencing the Project Achilles datasets. The amplified genes represented a number of gene families, including epigenetic regulators, cell cycle-associated genes, DNA damage response/repair genes, metabolic regulators, and genes linked to the Wnt, Notch, Hedgehog, JAK/STAT, NF-KB and MAPK signaling pathways. Among the 42 putative driver genes were known driver genes, such as EGFR, ERBB2 and PIK3CA. Wild-type KRAS was amplified in several cancer types, and KRAS-amplified cancer cell lines were most sensitive to KRAS shRNA, suggesting that KRAS amplification was an independent oncogenic event. A number of MAP kinase adapters were co-amplified with their receptor tyrosine kinases, such as the FGFR adapter FRS2 and the EGFR family adapters GRB2 and GRB7. The ubiquitin-like ligase DCUN1D1 and the histone methyltransferase NSD3 were also identified as novel putative cancer driver genes. We discuss the patient tailoring implications for existing cancer drug targets and we further discuss potential novel opportunities for drug discovery efforts.

Identification of Druggable Cancer Driver Genes Amplified across TCGA Datasets

PubMed Central

Chen, Ying; McGee, Jeremy; Chen, Xianming; Doman, Thompson N.; Gong, Xueqian; Zhang, Youyan; Hamm, Nicole; Ma, Xiwen; Higgs, Richard E.; Bhagwat, Shripad V.; Buchanan, Sean; Peng, Sheng-Bin; Staschke, Kirk A.; Yadav, Vipin; Yue, Yong; Kouros-Mehr, Hosein

2014-01-01

The Cancer Genome Atlas (TCGA) projects have advanced our understanding of the driver mutations, genetic backgrounds, and key pathways activated across cancer types. Analysis of TCGA datasets have mostly focused on somatic mutations and translocations, with less emphasis placed on gene amplifications. Here we describe a bioinformatics screening strategy to identify putative cancer driver genes amplified across TCGA datasets. We carried out GISTIC2 analysis of TCGA datasets spanning 14 cancer subtypes and identified 461 genes that were amplified in two or more datasets. The list was narrowed to 73 cancer-associated genes with potential “druggable” properties. The majority of the genes were localized to 14 amplicons spread across the genome. To identify potential cancer driver genes, we analyzed gene copy number and mRNA expression data from individual patient samples and identified 40 putative cancer driver genes linked to diverse oncogenic processes. Oncogenic activity was further validated by siRNA/shRNA knockdown and by referencing the Project Achilles datasets. The amplified genes represented a number of gene families, including epigenetic regulators, cell cycle-associated genes, DNA damage response/repair genes, metabolic regulators, and genes linked to the Wnt, Notch, Hedgehog, JAK/STAT, NF-KB and MAPK signaling pathways. Among the 40 putative driver genes were known driver genes, such as EGFR, ERBB2 and PIK3CA. Wild-type KRAS was amplified in several cancer types, and KRAS-amplified cancer cell lines were most sensitive to KRAS shRNA, suggesting that KRAS amplification was an independent oncogenic event. A number of MAP kinase adapters were co-amplified with their receptor tyrosine kinases, such as the FGFR adapter FRS2 and the EGFR family adapter GRB7. The ubiquitin-like ligase DCUN1D1 and the histone methyltransferase NSD3 were also identified as novel putative cancer driver genes. We discuss the patient tailoring implications for existing cancer drug targets and we further discuss potential novel opportunities for drug discovery efforts. PMID:24874471

The Colony-Stimulating Factor 3 Receptor T640N Mutation Is Oncogenic, Sensitive to JAK Inhibition, and Mimics T618I.

PubMed

Maxson, Julia E; Luty, Samuel B; MacManiman, Jason D; Paik, Jason C; Gotlib, Jason; Greenberg, Peter; Bahamadi, Swaleh; Savage, Samantha L; Abel, Melissa L; Eide, Christopher A; Loriaux, Marc M; Stevens, Emily A; Tyner, Jeffrey W

2016-02-01

Colony-stimulating factor 3 receptor (CSF3R) mutations have been identified in the majority of chronic neutrophilic leukemia (CNL) and a smaller percentage of atypical chronic myeloid leukemia (aCML) cases. Although CSF3R point mutations (e.g., T618I) are emerging as key players in CNL/aCML, the significance of rarer CSF3R mutations is unknown. In this study, we assess the importance of the CSF3R T640N mutation as a marker of CNL/aCML and potential therapeutic target. Sanger sequencing of leukemia samples was performed to identify CSF3R mutations in CNL and aCML. The oncogenicity of the CSF3R T640N mutation relative to the T618I mutation was assessed by cytokine independent growth assays and by mouse bone marrow transplant. Receptor dimerization and O-glycosylation of the mutants was assessed by Western blot, and JAK inhibitor sensitivity was assessed by colony assay. Here, we identify a CSF3R T640N mutation in two patients with CNL/aCML, one of whom was originally diagnosed with MDS and acquired the T640N mutation upon evolution of disease to aCML. The T640N mutation is oncogenic in cellular transformation assays and an in vivo mouse bone marrow transplantation model. It exhibits many similar phenotypic features to T618I, including ligand independence and altered patterns of O-glycosylation--despite the transmembrane location of T640 preventing access by GalNAc transferase enzymes. Cells transformed by the T640N mutation are sensitive to JAK kinase inhibition to a similar degree as cells transformed by CSF3R T618I. Because of its similarities to CSF3R T618I, the T640N mutation likely has diagnostic and therapeutic relevance in CNL/aCML. ©2015 American Association for Cancer Research.

Myb proteins: angels and demons in normal and transformed cells

PubMed Central

Zhou, Ye; Ness, Scott A.

2013-01-01

A key regulator of proliferation, differentiation and cell fate, the c-Myb transcription factor regulates the expression of hundreds of genes and is in turn regulated by numerous pathways and protein interactions. However, the most unique feature of c-Myb is that it can be converted into an oncogenic transforming protein through a few mutations that completely change its activity and specificity. The c-Myb protein is a myriad of interactions and activities rolled up in a protein that controls proliferation and differentiation in many different cell types. Here we discuss the background and recent progress that have led to a better understanding of this complex protein, and outline the questions that have yet to be answered. PMID:21196221

Effects of oncogenic mutations on the conformational free-energy landscape of EGFR kinase

PubMed Central

Sutto, Ludovico; Gervasio, Francesco Luigi

2013-01-01

Activating mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase are frequently found in many cancers. It has been suggested that changes in the equilibrium between its active and inactive conformations are linked to its oncogenic potential. Here, we quantify the effects of some of the most common single (L858R and T790M) and double (T790M-L858R) oncogenic mutations on the conformational free-energy landscape of the EGFR kinase domain by using massive molecular dynamics simulations together with parallel tempering, metadynamics, and one of the best force-fields available. Whereas the wild-type EGFR catalytic domain monomer is mostly found in an inactive conformation, our results show a clear shift toward the active conformation for all of the mutants. The L858R mutation stabilizes the active conformation at the expense of the inactive conformation and rigidifies the αC-helix. The T790M gatekeeper mutant favors activation by stabilizing a hydrophobic cluster. Finally, T790M with L858R shows a significant positive epistasis effect. This combination not only stabilizes the active conformation, but in nontrivial ways changes the free-energy landscape lowering the transition barriers. PMID:23754386

Effects of oncogenic mutations on the conformational free-energy landscape of EGFR kinase.

PubMed

Sutto, Ludovico; Gervasio, Francesco Luigi

2013-06-25

Activating mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase are frequently found in many cancers. It has been suggested that changes in the equilibrium between its active and inactive conformations are linked to its oncogenic potential. Here, we quantify the effects of some of the most common single (L858R and T790M) and double (T790M-L858R) oncogenic mutations on the conformational free-energy landscape of the EGFR kinase domain by using massive molecular dynamics simulations together with parallel tempering, metadynamics, and one of the best force-fields available. Whereas the wild-type EGFR catalytic domain monomer is mostly found in an inactive conformation, our results show a clear shift toward the active conformation for all of the mutants. The L858R mutation stabilizes the active conformation at the expense of the inactive conformation and rigidifies the αC-helix. The T790M gatekeeper mutant favors activation by stabilizing a hydrophobic cluster. Finally, T790M with L858R shows a significant positive epistasis effect. This combination not only stabilizes the active conformation, but in nontrivial ways changes the free-energy landscape lowering the transition barriers.

The long tail of oncogenic drivers in prostate cancer.

PubMed

Armenia, Joshua; Wankowicz, Stephanie A M; Liu, David; Gao, Jianjiong; Kundra, Ritika; Reznik, Ed; Chatila, Walid K; Chakravarty, Debyani; Han, G Celine; Coleman, Ilsa; Montgomery, Bruce; Pritchard, Colin; Morrissey, Colm; Barbieri, Christopher E; Beltran, Himisha; Sboner, Andrea; Zafeiriou, Zafeiris; Miranda, Susana; Bielski, Craig M; Penson, Alexander V; Tolonen, Charlotte; Huang, Franklin W; Robinson, Dan; Wu, Yi Mi; Lonigro, Robert; Garraway, Levi A; Demichelis, Francesca; Kantoff, Philip W; Taplin, Mary-Ellen; Abida, Wassim; Taylor, Barry S; Scher, Howard I; Nelson, Peter S; de Bono, Johann S; Rubin, Mark A; Sawyers, Charles L; Chinnaiyan, Arul M; Schultz, Nikolaus; Van Allen, Eliezer M

2018-05-01

Comprehensive genomic characterization of prostate cancer has identified recurrent alterations in genes involved in androgen signaling, DNA repair, and PI3K signaling, among others. However, larger and uniform genomic analysis may identify additional recurrently mutated genes at lower frequencies. Here we aggregate and uniformly analyze exome sequencing data from 1,013 prostate cancers. We identify and validate a new class of E26 transformation-specific (ETS)-fusion-negative tumors defined by mutations in epigenetic regulators, as well as alterations in pathways not previously implicated in prostate cancer, such as the spliceosome pathway. We find that the incidence of significantly mutated genes (SMGs) follows a long-tail distribution, with many genes mutated in less than 3% of cases. We identify a total of 97 SMGs, including 70 not previously implicated in prostate cancer, such as the ubiquitin ligase CUL3 and the transcription factor SPEN. Finally, comparing primary and metastatic prostate cancer identifies a set of genomic markers that may inform risk stratification.

Whole-genome sequencing of an aggressive BRAF wild-type papillary thyroid cancer identified EML4-ALK translocation as a therapeutic target.

PubMed

Demeure, Michael J; Aziz, Meraj; Rosenberg, Richard; Gurley, Steven D; Bussey, Kimberly J; Carpten, John D

2014-06-01

Recent advances in the treatment of cancer have focused on targeting genomic aberrations with selective therapeutic agents. In radioiodine resistant aggressive papillary thyroid cancers, there remain few effective therapeutic options. A 62-year-old man who underwent multiple operations for papillary thyroid cancer and whose metastases progressed despite standard treatments provided tumor tissue. We analyzed tumor and whole blood DNA by whole genome sequencing, achieving 80× or greater coverage over 94 % of the exome and 90 % of the genome. We determined somatic mutations and structural alterations. We found a total of 57 somatic mutations in 55 genes of the cancer genome. There was notably a lack of mutations in NRAS and BRAF, and no RET/PTC rearrangement. There was a mutation in the TRAPP oncogene and a loss of heterozygosity of the p16, p18, and RB1 tumor suppressor genes. The oncogenic driver for this tumor is a translocation involving the genes for anaplastic lymphoma receptor tyrosine kinase (ALK) and echinoderm microtubule associated protein like 4 (EML4). The EML4-ALK translocation has been reported in approximately 5 % of lung cancers, as well as in pediatric neuroblastoma, and is a therapeutic target for crizotinib. This is the first report of the whole genomic sequencing of a papillary thyroid cancer in which we identified an EML4-ALK translocation of a TRAPP oncogene mutation. These findings suggest that this tumor has a more distinct oncogenesis than BRAF mutant papillary thyroid cancer. Whole genome sequencing can elucidate an oncogenic context and expose potential therapeutic vulnerabilities in rare cancers.

EGFR and Ras regulate DDX59 during lung cancer development.

PubMed

Yang, Lin; Zhang, Hanyin; Chen, Dan; Ding, Peikun; Yuan, Yunchang; Zhang, Yandong

2018-02-05

Oncogenes EGFR and ras are frequently mutated and activated in human lung cancers. In this report, we found that both EGFR and Ras signaling can upregulate RNA helicase DDX59 in lung cancer cells. DDX59 can be induced through the mitogen activated protein kinase (MAPK) pathway after EGFR or Ras activation. Inhibitors for Ras/Raf/MAP pathway significantly decreased DDX59 expression at both protein and mRNA levels. Through immunohistochemistry, we found that DDX59 protein expression correlated with Ras and EGFR mutation status in human lung adenocarcinoma. Finally, through a xenograft nude mice model, we demonstrated that DDX59 is pivotal for EGFR mutated lung cancer cell growth in vivo. Our study identified a novel protein downstream of Ras and EGFR, which may serve as a potential therapeutic drug target for lung cancer patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantifying oncogenic phosphotyrosine signaling networks through systems biology.

PubMed

Del Rosario, Amanda M; White, Forest M

2010-02-01

Pathways linking oncogenic mutations to increased proliferative or migratory capacity are poorly characterized, yet provide potential targets for therapeutic intervention. As tyrosine phosphorylation signaling networks are known to mediate proliferation and migration, and frequently go awry in cancers, a comprehensive understanding of these networks in normal and diseased states is warranted. To this end, recent advances in mass spectrometry, protein microarrays, and computational algorithms provide insight into various aspects of the network including phosphotyrosine identification, analysis of kinase/phosphatase substrates, and phosphorylation-mediated protein-protein interactions. Here we detail technological advances underlying these system-level approaches and give examples of their applications. By combining multiple approaches, it is now possible to quantify changes in the phosphotyrosine signaling network with various oncogenic mutations, thereby unveiling novel therapeutic targets. Copyright 2009 Elsevier Ltd. All rights reserved.

Hippo-independent activation of YAP by the GNAQ uveal melanoma oncogene through a trio-regulated rho GTPase signaling circuitry.

PubMed

Feng, Xiaodong; Degese, Maria Sol; Iglesias-Bartolome, Ramiro; Vaque, Jose P; Molinolo, Alfredo A; Rodrigues, Murilo; Zaidi, M Raza; Ksander, Bruce R; Merlino, Glenn; Sodhi, Akrit; Chen, Qianming; Gutkind, J Silvio

2014-06-16

Mutually exclusive activating mutations in the GNAQ and GNA11 oncogenes, encoding heterotrimeric Gαq family members, have been identified in ∼ 83% and ∼ 6% of uveal and skin melanomas, respectively. However, the molecular events underlying these GNAQ-driven malignancies are not yet defined, thus limiting the ability to develop cancer-targeted therapies. Here, we focused on the transcriptional coactivator YAP, a critical component of the Hippo signaling pathway that controls organ size. We found that Gαq stimulates YAP through a Trio-Rho/Rac signaling circuitry promoting actin polymerization, independently of phospholipase Cβ and the canonical Hippo pathway. Furthermore, we show that Gαq promotes the YAP-dependent growth of uveal melanoma cells, thereby identifying YAP as a suitable therapeutic target in uveal melanoma, a GNAQ/GNA11-initiated human malignancy. Copyright © 2014 Elsevier Inc. All rights reserved.

Distinct Neural Stem Cell Populations Give Rise to Disparate Brain Tumors in Response to N-MYC

PubMed Central

Swartling, Fredrik J.; Savov, Vasil; Persson, Anders I.; Chen, Justin; Hackett, Christopher S.; Northcott, Paul A.; Grimmer, Matthew R.; Lau, Jasmine; Chesler, Louis; Perry, Arie; Phillips, Joanna J.; Taylor, Michael D.; Weiss, William A.

2012-01-01

SUMMARY The proto-oncogene MYCN is mis-expressed in various types of human brain tumors. To clarify how developmental and regional differences influence transformation, we transduced wild-type or mutationally-stabilized murine N-mycT58A into neural stem cells (NSCs) from perinatal murine cerebellum, brain stem and forebrain. Transplantation of N-mycWT NSCs was insufficient for tumor formation. N-mycT58A cerebellar and brain stem NSCs generated medulloblastoma/primitive neuroectodermal tumors, whereas forebrain NSCs developed diffuse glioma. Expression analyses distinguished tumors generated from these different regions, with tumors from embryonic versus postnatal cerebellar NSCs demonstrating SHH-dependence and SHH-independence, respectively. These differences were regulated in-part by the transcription factor SOX9, activated in the SHH subclass of human medulloblastoma. Our results demonstrate context-dependent transformation of NSCs in response to a common oncogenic signal. PMID:22624711

Oncogenic mutations in melanomas and benign melanocytic nevi of the female genital tract

PubMed Central

Tseng, Diane; Kim, Julie; Warrick, Andrea; Nelson, Dylan; Pukay, Marina; Beadling, Carol; Heinrich, Michael; Selim, Maria Angelica; Corless, Christopher L.; Nelson, Kelly

2015-01-01

Background The genetic heterogeneity of melanomas and melanocytic nevi of the female genital tract is poorly understood. Objective We aim to characterize the frequency of mutations of the following genes: BRAF, NRAS, KIT, GNA11, and GNAQ in female genital tract melanomas. We also characterize the frequency of BRAF mutations in female genital tract melanomas compared with melanocytic nevi. Methods Mutational screening was performed on the following female genital tract melanocytic neoplasms: 25 melanomas, 7 benign melanocytic nevi, and 4 atypical melanocytic nevi. Results Of the 25 female genital tract melanoma specimens queried, KIT mutations were detected in 4 (16.0%), NRAS mutations in 4 (16.0%), and BRAF mutations in 2 (8.0%) samples. Two of the tumors with KIT mutations harbored double mutations in the same exon. No GNAQ or GNA11 mutations were identified among 11 melanomas screened. BRAF V600E mutations were detected in 7 of 7 benign melanocytic genital nevi (100%) and 3 of 4 atypical genital nevi (75%). Limitations Our study is limited by the small sample size of this rare subset of melanomas. Conclusion KIT, NRAS, and BRAF mutations are found in a subset of female genital tract melanomas. Screening for oncogenic mutations is important for developing and applying clinical therapies for melanomas of the female genital tract. PMID:24842760

MET-oncogenic and JAK2-inactivating alterations are independent factors that affect regulation of PD-L1 expression in lung cancer.

PubMed

Saigi, Maria; Alburquerque-Bejar, Juan J; McLEER-Florin, Anne; Pereira, Carolina; Pros, Eva; Romero, Octavio A; Baixeras, Nuria; Esteve-Codina, Anna; Nadal, Ernest; Brambilla, Elisabeth; Sanchez-Cespedes, Montse

2018-06-13

The blockade of immune checkpoints such as PD-L1 and PD-1 is being exploited therapeutically in several types of malignancies. Here, we aimed to understand the contribution of the genetics of lung cancer (LC) to the ability of tumor cells to escape immunosurveillance checkpoints. Over 150 primary non-small cell lung cancers, including pulmonary sarcomatoid carcinomas, were tested for the levels of HLA-I complex, PD-L1, tumor-infiltrating CD8+ lymphocytes and alterations in main LC genes. Correlations were validated in cancer cell lines using appropriate treatments to activate or inhibit selected pathways. We also performed RNA sequencing to assess changes in gene expression after these treatments Results: MET-oncogenic activation tended to associate with positive PD-L1 immunostaining, whereas STK11 mutations were correlated with negative immunostaining. In MET-altered cancer cells, MET triggered a transcriptional increase of PD-L1 that was independent of the IFNγ-mediated JAK/STAT pathway. The activation of MET also up-regulated other immunosuppressive genes (PDCD1LG2 and SOCS1), and transcripts involved in angiogenesis (VEGFA and NRP1) and in cell proliferation. We also report recurrent inactivating mutations in JAK2 that co-occur with alterations in MET and STK11, which prevented the induction of immunoresponse-related genes following treatment with IFNγ. We show that MET activation promotes the expression of several negative checkpoint regulators of the immunoresponse, including PD-L1. In addition, we report inactivation of JAK2 in LC cells that prevented the response to IFNγ. These alterations are likely to facilitate tumor growth by enabling immune tolerance and may affect the response to immune checkpoint inhibitors. Copyright ©2018, American Association for Cancer Research.

Fatty acid synthase mediates EGFR palmitoylation in EGFR mutated non-small cell lung cancer.

PubMed

Ali, Azhar; Levantini, Elena; Teo, Jun Ting; Goggi, Julian; Clohessy, John G; Wu, Chan Shuo; Chen, Leilei; Yang, Henry; Krishnan, Indira; Kocher, Olivier; Zhang, Junyan; Soo, Ross A; Bhakoo, Kishore; Chin, Tan Min; Tenen, Daniel G

2018-02-15

Metabolic reprogramming is widely known as a hallmark of cancer cells to allow adaptation of cells to sustain survival signals. In this report, we describe a novel oncogenic signaling pathway exclusively acting in mutated epidermal growth factor receptor (EGFR) non-small cell lung cancer (NSCLC) with acquired tyrosine kinase inhibitor (TKI) resistance. Mutated EGFR mediates TKI resistance through regulation of the fatty acid synthase (FASN), which produces 16-C saturated fatty acid palmitate. Our work shows that the persistent signaling by mutated EGFR in TKI-resistant tumor cells relies on EGFR palmitoylation and can be targeted by Orlistat, an FDA-approved anti-obesity drug. Inhibition of FASN with Orlistat induces EGFR ubiquitination and abrogates EGFR mutant signaling, and reduces tumor growths both in culture systems and in vivo Together, our data provide compelling evidence on the functional interrelationship between mutated EGFR and FASN and that the fatty acid metabolism pathway is a candidate target for acquired TKI-resistant EGFR mutant NSCLC patients. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

Mouse model of proximal colon-specific tumorigenesis driven by microsatellite instability-induced Cre-mediated inactivation of Apc and activation of Kras.

PubMed

Kawaguchi, Yasuo; Hinoi, Takao; Saito, Yasufumi; Adachi, Tomohiro; Miguchi, Masashi; Niitsu, Hiroaki; Sasada, Tatsunari; Shimomura, Manabu; Egi, Hiroyuki; Oka, Shiro; Tanaka, Shinji; Chayama, Kazuaki; Sentani, Kazuhiro; Oue, Naohide; Yasui, Wataru; Ohdan, Hideki

2016-05-01

KRAS gene mutations are found in 40-50% of colorectal cancer cases, but their functional contribution is not fully understood. To address this issue, we generated genetically engineered mice with colon tumors expressing an oncogenic Kras(G12D) allele in the context of the Adenomatous polyposis coli (Apc) deficiency to compare them to tumors harboring Apc deficiency alone. CDX2P9.5-G22Cre (referred to as G22Cre) mice showing inducible Cre recombinase transgene expression in the proximal colon controlled under the CDX2 gene promoter were intercrossed with Apc (flox/flox) mice and LSL-Kras (G12D) mice carrying loxP-flanked Apc and Lox-Stop-Lox oncogenic Kras(G12D) alleles, respectively, to generate G22Cre; Apc(flox/flox); Kras(G12D) and G22Cre; Apc(flox/flox); KrasWT mice. Gene expression profiles of the tumors were analyzed using high-density oligonucleotide arrays. Morphologically, minimal difference in proximal colon tumor was observed between the two mouse models. Consistent with previous findings in vitro, Glut1 transcript and protein expression was up-regulated in the tumors of G22Cre;Apc (flox/flox) ; Kras(G12D) mice. Immunohistochemical staining analysis revealed that GLUT1 protein expression correlated with KRAS mutations in human colorectal cancer. Microarray analysis identified 11 candidate genes upregulated more than fivefold and quantitative PCR analysis confirmed that Aqp8, Ttr, Qpct, and Slc26a3 genes were upregulated 3.7- to 30.2-fold in tumors with mutant Kras. These results demonstrated the validity of the G22Cre; Apc(flox/flox) ;Kras (G12D) mice as a new mouse model with oncogenic Kras activation. We believe that this model can facilitate efforts to define novel factors that contribute to the pathogenesis of human colorectal cancer with KRAS mutations.

Oncogenic signalling pathways in benign odontogenic cysts and tumours.

PubMed

Diniz, Marina Gonçalves; Gomes, Carolina Cavalieri; de Sousa, Sílvia Ferreira; Xavier, Guilherme Machado; Gomez, Ricardo Santiago

2017-09-01

The first step towards the prevention of cancer is to develop an in-depth understanding of tumourigenesis and the molecular basis of malignant transformation. What drives tumour initiation? Why do most benign tumours fail to metastasize? Oncogenic mutations, previously considered to be the hallmark drivers of cancers, are reported in benign cysts and tumours, including those that have an odontogenic origin. Despite the presence of such alterations, the vast majority of odontogenic lesions are benign and never progress to the stage of malignant transformation. As these lesions are likely to develop due to developmental defects, it is possible that they harbour quiet genomes. Now the question arises - do they result from DNA replication errors? Specific candidate genes have been sequenced in odontogenic lesions, revealing recurrent BRAF mutation in the case of ameloblastoma, KRAS mutation in adenomatoid odontogenic tumours, PTCH1 mutation in odontogenic keratocysts, and CTNNB1 (Beta-catenin) mutation in calcifying odontogenic cysts. Studies on these benign and rare entities might reveal important information about the tumorigenic process and the mechanisms that hinder/halt neoplastic progression. This is because the role of relatively common oncogenic mutations seems to be context dependent. In this review, each mutation signature of the odontogenic lesion and the affected signalling pathways are discussed in the context of tooth development and tumorigenesis. Furthermore, behavioural differences between different types of odontogenic lesions are explored and discussed based on the molecular alteration described. This review also includes the employment of molecular results for guiding therapeutic approaches towards odontogenic lesions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differential Reprogramming of Isogenic Colorectal Cancer Cells by Distinct Activating KRAS Mutations

PubMed Central

2015-01-01

Oncogenic mutations of Ras at codons 12, 13, or 61, that render the protein constitutively active, are found in ∼16% of all cancer cases. Among the three major Ras isoforms, KRAS is the most frequently mutated isoform in cancer. Each Ras isoform and tumor type displays a distinct pattern of codon-specific mutations. In colon cancer, KRAS is typically mutated at codon 12, but a significant fraction of patients have mutations at codon 13. Clinical data suggest different outcomes and responsiveness to treatment between these two groups. To investigate the differential effects upon cell status associated with KRAS mutations we performed a quantitative analysis of the proteome and phosphoproteome of isogenic SW48 colon cancer cell lines in which one allele of the endogenous gene has been edited to harbor specific KRAS mutations (G12V, G12D, or G13D). Each mutation generates a distinct signature, with the most variability seen between G13D and the codon 12 KRAS mutants. One notable example of specific up-regulation in KRAS codon 12 mutant SW48 cells is provided by the short form of the colon cancer stem cell marker doublecortin-like Kinase 1 (DCLK1) that can be reversed by suppression of KRAS. PMID:25599653

B-Raf mutation: a key player in molecular biology of cancer.

PubMed

Rahman, M A; Salajegheh, A; Smith, R A; Lam, A K-Y

2013-12-01

B-Raf is one of the more commonly mutated proto-oncogenes implicated in the development of cancers. In this review, we consider the mechanisms and clinical impacts of B-Raf mutations in cancer and discuss the implications for the patient in melanoma, thyroid cancer and colorectal cancer, where B-Raf mutations are particularly common. © 2013.

CRISPR-Cas9-mediated saturated mutagenesis screen predicts clinical drug resistance with improved accuracy.

PubMed

Ma, Leyuan; Boucher, Jeffrey I; Paulsen, Janet; Matuszewski, Sebastian; Eide, Christopher A; Ou, Jianhong; Eickelberg, Garrett; Press, Richard D; Zhu, Lihua Julie; Druker, Brian J; Branford, Susan; Wolfe, Scot A; Jensen, Jeffrey D; Schiffer, Celia A; Green, Michael R; Bolon, Daniel N

2017-10-31

Developing tools to accurately predict the clinical prevalence of drug-resistant mutations is a key step toward generating more effective therapeutics. Here we describe a high-throughput CRISPR-Cas9-based saturated mutagenesis approach to generate comprehensive libraries of point mutations at a defined genomic location and systematically study their effect on cell growth. As proof of concept, we mutagenized a selected region within the leukemic oncogene BCR-ABL1 Using bulk competitions with a deep-sequencing readout, we analyzed hundreds of mutations under multiple drug conditions and found that the effects of mutations on growth in the presence or absence of drug were critical for predicting clinically relevant resistant mutations, many of which were cancer adaptive in the absence of drug pressure. Using this approach, we identified all clinically isolated BCR-ABL1 mutations and achieved a prediction score that correlated highly with their clinical prevalence. The strategy described here can be broadly applied to a variety of oncogenes to predict patient mutations and evaluate resistance susceptibility in the development of new therapeutics. Published under the PNAS license.

Cancer genes mutation profiling in calcifying epithelial odontogenic tumour.

PubMed

de Sousa, Sílvia Ferreira; Diniz, Marina Gonçalves; França, Josiane Alves; Fontes Pereira, Thaís Dos Santos; Moreira, Rennan Garcias; Santos, Jean Nunes Dos; Gomez, Ricardo Santiago; Gomes, Carolina Cavalieri

2018-03-01

To identify calcifying epithelial odontogenic tumour (CEOT) mutations in oncogenes and tumour suppressor genes. A panel of 50 genes commonly mutated in cancer was sequenced in CEOT by next-generation sequencing. Sanger sequencing was used to cover the region of the frameshift deletion identified in one sample. Missense single nucleotide variants (SNVs) with minor allele frequency (MAF) <1% were detected in PTEN , MET and JAK3 . A frameshift deletion in CDKN2A occurred in association with a missense mutation in the same gene region, suggesting a second hit in the inactivation of this gene. APC, KDR, KIT, PIK3CA and TP53 missense SNVs were identified; however, these are common SNVs, showing MAF >1%. CEOT harbours mutations in the tumour suppressor PTEN and CDKN2A and in the oncogenes JAK3 and MET . As these mutations occurred in only one case each, they are probably not driver mutations for these tumours. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

BRD4-targeted therapy induces Myc-independent cytotoxicity in Gnaq/11-mutatant uveal melanoma cells.

PubMed

Ambrosini, Grazia; Sawle, Ashley D; Musi, Elgilda; Schwartz, Gary K

2015-10-20

Uveal melanoma (UM) is an aggressive intraocular malignancy with limited therapeutic options. Both primary and metastatic UM are characterized by oncogenic mutations in the G-protein alpha subunit q and 11. Furthermore, nearly 40% of UM has amplification of the chromosomal arm 8q and monosomy of chromosome 3, with consequent anomalies of MYC copy number. Chromatin regulators have become attractive targets for cancer therapy. In particular, the bromodomain and extra-terminal (BET) inhibitor JQ1 has shown selective inhibition of c-Myc expression with antiproliferative activity in hematopoietic and solid tumors. Here we provide evidence that JQ1 had cytotoxic activity in UM cell lines carrying Gnaq/11 mutations, while in cells without the mutations had little effects. Using microarray analysis, we identified a large subset of genes modulated by JQ1 involved in the regulation of cell cycle, apoptosis and DNA repair. Further analysis of selected genes determined that the concomitant silencing of Bcl-xL and Rad51 represented the minimal requirement to mimic the apoptotic effects of JQ1 in the mutant cells, independently of c-Myc. In addition, administration of JQ1 to mouse xenograft models of Gnaq-mutant UM resulted in significant inhibition of tumor growth.Collectively, our results define BRD4 targeting as a novel therapeutic intervention against UM with Gnaq/Gna11 mutations.

Mutant p53 Promotes Tumor Cell Malignancy by Both Positive and Negative Regulation of the Transforming Growth Factor β (TGF-β) Pathway*

PubMed Central

Ji, Lei; Xu, Jinjin; Liu, Jian; Amjad, Ali; Zhang, Kun; Liu, Qingwu; Zhou, Lei; Xiao, Jianru; Li, Xiaotao

2015-01-01

Specific p53 mutations abrogate tumor-suppressive functions by gaining new abilities to promote tumorigenesis. Inactivation of p53 is known to distort TGF-β signaling, which paradoxically displays both tumor-suppressive and pro-oncogenic functions. The molecular mechanisms of how mutant p53 simultaneously antagonizes the tumor-suppressive and synergizes the tumor-promoting function of the TGF-β pathway remain elusive. Here we demonstrate that mutant p53 differentially regulates subsets of TGF-β target genes by enhanced binding to the MH2 domain in Smad3 upon the integration of ERK signaling, therefore disrupting Smad3/Smad4 complex formation. Silencing Smad2, inhibition of ERK, or introducing a phosphorylation-defective mutation at Ser-392 in p53 abrogates the R175H mutant p53-dependent regulation of these TGF-β target genes. Our study shows a mechanism to reconcile the seemingly contradictory observations that mutant p53 can both attenuate and cooperate with the TGF-β pathway to promote cancer cell malignancy in the same cell type. PMID:25767119

MSH3-deficiency initiates EMAST without oncogenic transformation of human colon epithelial cells.

PubMed

Campregher, Christoph; Schmid, Gerald; Ferk, Franziska; Knasmüller, Siegfried; Khare, Vineeta; Kortüm, Benedikt; Dammann, Kyle; Lang, Michaela; Scharl, Theresa; Spittler, Andreas; Roig, Andres I; Shay, Jerry W; Gerner, Christopher; Gasche, Christoph

2012-01-01

Elevated microsatellite instability at selected tetranucleotide repeats (EMAST) is a genetic signature in certain cases of sporadic colorectal cancer and has been linked to MSH3-deficiency. It is currently controversial whether EMAST is associated with oncogenic properties in humans, specifically as cancer development in Msh3-deficient mice is not enhanced. However, a mutator phenotype is different between species as the genetic positions of repetitive sequences are not conserved. Here we studied the molecular effects of human MSH3-deficiency. HCT116 and HCT116+chr3 (both MSH3-deficient) and primary human colon epithelial cells (HCEC, MSH3-wildtype) were stably transfected with an EGFP-based reporter plasmid for the detection of frameshift mutations within an [AAAG]17 repeat. MSH3 was silenced by shRNA and changes in protein expression were analyzed by shotgun proteomics. Colony forming assay was used to determine oncogenic transformation and double strand breaks (DSBs) were assessed by Comet assay. Despite differential MLH1 expression, both HCT116 and HCT116+chr3 cells displayed comparable high mutation rates (about 4×10(-4)) at [AAAG]17 repeats. Silencing of MSH3 in HCECs leads to a remarkable increased frameshift mutations in [AAAG]17 repeats whereas [CA]13 repeats were less affected. Upon MSH3-silencing, significant changes in the expression of 202 proteins were detected. Pathway analysis revealed overexpression of proteins involved in double strand break repair (MRE11 and RAD50), apoptosis, L1 recycling, and repression of proteins involved in metabolism, tRNA aminoacylation, and gene expression. MSH3-silencing did not induce oncogenic transformation and DSBs increased 2-fold. MSH3-deficiency in human colon epithelial cells results in EMAST, formation of DSBs and significant changes of the proteome but lacks oncogenic transformation. Thus, MSH3-deficiency alone is unlikely to drive human colon carcinogenesis.

MSH3-Deficiency Initiates EMAST without Oncogenic Transformation of Human Colon Epithelial Cells

PubMed Central

Campregher, Christoph; Schmid, Gerald; Ferk, Franziska; Knasmüller, Siegfried; Khare, Vineeta; Kortüm, Benedikt; Dammann, Kyle; Lang, Michaela; Scharl, Theresa; Spittler, Andreas; Roig, Andres I.; Shay, Jerry W.; Gerner, Christopher; Gasche, Christoph

2012-01-01

Background/Aim Elevated microsatellite instability at selected tetranucleotide repeats (EMAST) is a genetic signature in certain cases of sporadic colorectal cancer and has been linked to MSH3-deficiency. It is currently controversial whether EMAST is associated with oncogenic properties in humans, specifically as cancer development in Msh3-deficient mice is not enhanced. However, a mutator phenotype is different between species as the genetic positions of repetitive sequences are not conserved. Here we studied the molecular effects of human MSH3-deficiency. Methods HCT116 and HCT116+chr3 (both MSH3-deficient) and primary human colon epithelial cells (HCEC, MSH3-wildtype) were stably transfected with an EGFP-based reporter plasmid for the detection of frameshift mutations within an [AAAG]17 repeat. MSH3 was silenced by shRNA and changes in protein expression were analyzed by shotgun proteomics. Colony forming assay was used to determine oncogenic transformation and double strand breaks (DSBs) were assessed by Comet assay. Results Despite differential MLH1 expression, both HCT116 and HCT116+chr3 cells displayed comparable high mutation rates (about 4×10−4) at [AAAG]17 repeats. Silencing of MSH3 in HCECs leads to a remarkable increased frameshift mutations in [AAAG]17 repeats whereas [CA]13 repeats were less affected. Upon MSH3-silencing, significant changes in the expression of 202 proteins were detected. Pathway analysis revealed overexpression of proteins involved in double strand break repair (MRE11 and RAD50), apoptosis, L1 recycling, and repression of proteins involved in metabolism, tRNA aminoacylation, and gene expression. MSH3-silencing did not induce oncogenic transformation and DSBs increased 2-fold. Conclusions MSH3-deficiency in human colon epithelial cells results in EMAST, formation of DSBs and significant changes of the proteome but lacks oncogenic transformation. Thus, MSH3-deficiency alone is unlikely to drive human colon carcinogenesis. PMID:23209772

Chromatin-Bound IκBα Regulates a Subset of Polycomb Target Genes in Differentiation and Cancer

PubMed Central

Mulero, María Carmen; Ferres-Marco, Dolors; Islam, Abul; Margalef, Pol; Pecoraro, Matteo; Toll, Agustí; Drechsel, Nils; Charneco, Cristina; Davis, Shelly; Bellora, Nicolás; Gallardo, Fernando; López-Arribillaga, Erika; Asensio-Juan, Elena; Rodilla, Verónica; González, Jessica; Iglesias, Mar; Shih, Vincent; Albà, M. Mar; Di Croce, Luciano; Hoffmann, Alexander; Miyamoto, Shigeki; Villà-Freixa, Jordi; López-Bigas, Nuria; Keyes, William M.; Domínguez, María; Bigas, Anna; Espinosa, Lluís

2014-01-01

Summary IκB proteins are the primary inhibitors of NF-κB. Here, we demonstrate that sumoylated and phosphorylated IκBα accumulates in the nucleus of keratinocytes and interacts with histones H2A and H4 at the regulatory region of HOX and IRX genes. Chromatin-bound IκBα modulates Polycomb recruitment and imparts their competence to be activated by TNFα. Mutations in the Drosophila IκBα gene cactus enhance the homeotic phenotype of Polycomb mutants, which is not counteracted by mutations in dorsal/NF-κB. Oncogenic transformation of keratinocytes results in cytoplasmic IκBα translocation associated with a massive activation of Hox. Accumulation of cytoplasmic IκBα was found in squamous cell carcinoma (SCC) associated with IKK activation and HOX upregulation. PMID:23850221

ASXL1 mutation correction by CRISPR/Cas9 restores gene function in leukemia cells and increases survival in mouse xenografts

PubMed Central

Valletta, Simona; Dolatshad, Hamid; Bartenstein, Matthias; Yip, Bon Ham; Bello, Erica; Gordon, Shanisha; Yu, Yiting; Shaw, Jacqueline; Roy, Swagata; Scifo, Laura; Schuh, Anna; Pellagatti, Andrea; Fulga, Tudor A.; Verma, Amit; Boultwood, Jacqueline

2015-01-01

Recurrent somatic mutations of the epigenetic modifier and tumor suppressor ASXL1 are common in myeloid malignancies, including chronic myeloid leukemia (CML), and are associated with poor clinical outcome. CRISPR/Cas9 has recently emerged as a powerful and versatile genome editing tool for genome engineering in various species. We have used the CRISPR/Cas9 system to correct the ASXL1 homozygous nonsense mutation present in the CML cell line KBM5, which lacks ASXL1 protein expression. CRISPR/Cas9-mediated ASXL1 homozygous correction resulted in protein re-expression with restored normal function, including down-regulation of Polycomb repressive complex 2 target genes. Significantly reduced cell growth and increased myeloid differentiation were observed in ASXL1 mutation-corrected cells, providing new insights into the role of ASXL1 in human myeloid cell differentiation. Mice xenografted with mutation-corrected KBM5 cells showed significantly longer survival than uncorrected xenografts. These results show that the sole correction of a driver mutation in leukemia cells increases survival in vivo in mice. This study provides proof-of-concept for driver gene mutation correction via CRISPR/Cas9 technology in human leukemia cells and presents a strategy to illuminate the impact of oncogenic mutations on cellular function and survival. PMID:26623729

ASXL1 mutation correction by CRISPR/Cas9 restores gene function in leukemia cells and increases survival in mouse xenografts.

PubMed

Valletta, Simona; Dolatshad, Hamid; Bartenstein, Matthias; Yip, Bon Ham; Bello, Erica; Gordon, Shanisha; Yu, Yiting; Shaw, Jacqueline; Roy, Swagata; Scifo, Laura; Schuh, Anna; Pellagatti, Andrea; Fulga, Tudor A; Verma, Amit; Boultwood, Jacqueline

2015-12-29

Recurrent somatic mutations of the epigenetic modifier and tumor suppressor ASXL1 are common in myeloid malignancies, including chronic myeloid leukemia (CML), and are associated with poor clinical outcome. CRISPR/Cas9 has recently emerged as a powerful and versatile genome editing tool for genome engineering in various species. We have used the CRISPR/Cas9 system to correct the ASXL1 homozygous nonsense mutation present in the CML cell line KBM5, which lacks ASXL1 protein expression. CRISPR/Cas9-mediated ASXL1 homozygous correction resulted in protein re-expression with restored normal function, including down-regulation of Polycomb repressive complex 2 target genes. Significantly reduced cell growth and increased myeloid differentiation were observed in ASXL1 mutation-corrected cells, providing new insights into the role of ASXL1 in human myeloid cell differentiation. Mice xenografted with mutation-corrected KBM5 cells showed significantly longer survival than uncorrected xenografts. These results show that the sole correction of a driver mutation in leukemia cells increases survival in vivo in mice. This study provides proof-of-concept for driver gene mutation correction via CRISPR/Cas9 technology in human leukemia cells and presents a strategy to illuminate the impact of oncogenic mutations on cellular function and survival.

Graded effects of unregulated smooth muscle myosin on intestinal architecture, intestinal motility and vascular function in zebrafish.

PubMed

Abrams, Joshua; Einhorn, Zev; Seiler, Christoph; Zong, Alan B; Sweeney, H Lee; Pack, Michael

2016-05-01

Smooth muscle contraction is controlled by the regulated activity of the myosin heavy chain ATPase (Myh11). Myh11 mutations have diverse effects in the cardiovascular, digestive and genitourinary systems in humans and animal models. We previously reported a recessive missense mutation, meltdown (mlt), which converts a highly conserved tryptophan to arginine (W512R) in the rigid relay loop of zebrafish Myh11. The mlt mutation disrupts myosin regulation and non-autonomously induces invasive expansion of the intestinal epithelium. Here, we report two newly identified missense mutations in the switch-1 (S237Y) and coil-coiled (L1287M) domains of Myh11 that fail to complement mlt Cell invasion was not detected in either homozygous mutant but could be induced by oxidative stress and activation of oncogenic signaling pathways. The smooth muscle defect imparted by the mlt and S237Y mutations also delayed intestinal transit, and altered vascular function, as measured by blood flow in the dorsal aorta. The cell-invasion phenotype induced by the three myh11 mutants correlated with the degree of myosin deregulation. These findings suggest that the vertebrate intestinal epithelium is tuned to the physical state of the surrounding stroma, which, in turn, governs its response to physiologic and pathologic stimuli. Genetic variants that alter the regulation of smooth muscle myosin might be risk factors for diseases affecting the intestine, vasculature, and other tissues that contain smooth muscle or contractile cells that express smooth muscle proteins, particularly in the setting of redox stress. © 2016. Published by The Company of Biologists Ltd.

Just like the rest of evolution in Mother Nature, the evolution of cancers may be driven by natural selection, and not by haphazard mutations

PubMed Central

Zhang, Ju; Lou, Xiaomin; Zellmer, Lucas; Liu, Siqi; Xu, Ningzhi; Liao, D. Joshua

2014-01-01

Sporadic carcinogenesis starts from immortalization of a differentiated somatic cell or an organ-specific stem cell. The immortalized cell incepts a new or quasinew organism that lives like a parasite in the patient and usually proceeds to progressive simplification, constantly engendering intermediate organisms that are simpler than normal cells. Like organismal evolution in Mother Nature, this cellular simplification is a process of Darwinian selection of those mutations with growth- or survival-advantages, from numerous ones that occur randomly and stochastically. Therefore, functional gain of growth- or survival-sustaining oncogenes and functional loss of differentiation-sustaining tumor suppressor genes, which are hallmarks of cancer cells and contribute to phenotypes of greater malignancy, are not drivers of carcinogenesis but are results from natural selection of advantageous mutations. Besides this mutation-load dependent survival mechanism that is evolutionarily low and of an asexual nature, cancer cells may also use cell fusion for survival, which is an evolutionarily-higher mechanism and is of a sexual nature. Assigning oncogenes or tumor suppressor genes or their mutants as drivers to induce cancer in animals may somewhat coerce them to create man-made oncogenic pathways that may not really be a course of sporadic cancer formations in the human. PMID:25594068

RET fusion as a novel driver of medullary thyroid carcinoma.

PubMed

Grubbs, Elizabeth G; Ng, Patrick Kwok-Shing; Bui, Jacquelin; Busaidy, Naifa L; Chen, Ken; Lee, Jeffrey E; Lu, Xinyan; Lu, Hengyu; Meric-Bernstam, Funda; Mills, Gordon B; Palmer, Gary; Perrier, Nancy D; Scott, Kenneth L; Shaw, Kenna R; Waguespack, Steven G; Williams, Michelle D; Yelensky, Roman; Cote, Gilbert J

2015-03-01

Oncogenic RET tyrosine kinase gene fusions and activating mutations have recently been identified in lung cancers, prompting initiation of targeted therapy trials in this disease. Although RET point mutation has been identified as a driver of tumorigenesis in medullary thyroid carcinoma (MTC), no fusions have been described to date. We evaluated the role of RET fusion as an oncogenic driver in MTC. We describe a patient who died from aggressive sporadic MTC < 10 months after diagnosis. Her tumor was evaluated by means of next-generation sequencing, including an intronic capture strategy. A reciprocal translocation involving RET intron 12 was identified. The fusion was validated using a targeted break apart fluorescence in situ hybridization probe, and RNA sequencing confirmed the existence of an in-frame fusion transcript joining MYH13 exon 35 with RET exon 12. Ectopic expression of fusion product in a murine Ba/F3 cell reporter model established strong oncogenicity. Three tyrosine kinase inhibitors currently used to treat MTC in clinical practice blocked tumorigenic cell growth. This finding represents the report of a novel RET fusion, the first of its kind described in MTC. The finding of this potential novel oncogenic mechanism has clear implications for sporadic MTC, which in the majority of cases has no driver mutation identified. The presence of a RET fusion also provides a plausible target for RET tyrosine kinase inhibitor therapies.

Extracellular vesicle communication pathways as regulatory targets of oncogenic transformation.

PubMed

Choi, Dongsic; Lee, Tae Hoon; Spinelli, Cristiana; Chennakrishnaiah, Shilpa; D'Asti, Esterina; Rak, Janusz

2017-07-01

Pathogenesis of human cancers bridges intracellular oncogenic driver events and their impact on intercellular communication. Among multiple mediators of this 'pathological connectivity' the role of extracellular vesicles (EVs) and their subsets (exosomes, ectosomes, oncosomes) is of particular interest for several reasons. The release of EVs from cancer cells represents a unique mechanism of regulated expulsion of bioactive molecules, a process that also mediates cell-to-cell transfer of lipids, proteins, and nucleic acids. Biological effects of these processes have been implicated in several aspects of cancer-related pathology, including tumour growth, invasion, angiogenesis, metastasis, immunity and thrombosis. Notably, the emerging evidence suggests that oncogenic mutations may impact several aspects of EV-mediated cell-cell communication including: (i) EV release rate and protein content; (ii) molecular composition of cancer EVs; (iii) the inclusion of oncogenic and mutant macromolecules in the EV cargo; (iv) EV-mediated release of genomic DNA; (v) deregulation of mechanisms responsible for EV biogenesis (vesiculome) and (vi) mechanisms of EV uptake by cancer cells. Intriguingly, EV-mediated intercellular transfer of mutant and oncogenic molecules between subpopulations of cancer cells, their indolent counterparts and stroma may exert profound biological effects that often resemble (but are not tantamount to) oncogenic transformation, including changes in cell growth, clonogenicity and angiogenic phenotype, or cause cell stress and death. However, several biological barriers likely curtail a permanent horizontal transformation of normal cells through EV-mediated mechanisms. The ongoing analysis and targeting of EV-mediated intercellular communication pathways can be viewed as a new therapeutic paradigm in cancer, while the analysis of oncogenic cargo contained in EVs released from cancer cells into biofluids is being developed for clinical use as a biomarker and companion diagnostics. Indeed, studies are underway to further explore the multiple links between molecular causality in cancer and various aspects of cellular vesiculation. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Genomic Evolution of Prostate Cancer

DTIC Science & Technology

2014-10-01

Mutation characteristics. (a) Number of high-confidence somatic mutations across all foci. Non- silent , non- silent mutations; Unique, number of unique...genes harboring a non- silent mutation; Reported, gene reported to be mutated in references 9–12 and 14. (b) Spectrum of unique high confidence somatic...epigenetic and micr- oRNA-mediated inactivation of LRP1B, a modulator of the extracellular environment of thyroid cancer cells. Oncogene 2011; 30

Systematic analysis of mutation distribution in three dimensional protein structures identifies cancer driver genes.

PubMed

Fujimoto, Akihiro; Okada, Yukinori; Boroevich, Keith A; Tsunoda, Tatsuhiko; Taniguchi, Hiroaki; Nakagawa, Hidewaki

2016-05-26

Protein tertiary structure determines molecular function, interaction, and stability of the protein, therefore distribution of mutation in the tertiary structure can facilitate the identification of new driver genes in cancer. To analyze mutation distribution in protein tertiary structures, we applied a novel three dimensional permutation test to the mutation positions. We analyzed somatic mutation datasets of 21 types of cancers obtained from exome sequencing conducted by the TCGA project. Of the 3,622 genes that had ≥3 mutations in the regions with tertiary structure data, 106 genes showed significant skew in mutation distribution. Known tumor suppressors and oncogenes were significantly enriched in these identified cancer gene sets. Physical distances between mutations in known oncogenes were significantly smaller than those of tumor suppressors. Twenty-three genes were detected in multiple cancers. Candidate genes with significant skew of the 3D mutation distribution included kinases (MAPK1, EPHA5, ERBB3, and ERBB4), an apoptosis related gene (APP), an RNA splicing factor (SF1), a miRNA processing factor (DICER1), an E3 ubiquitin ligase (CUL1) and transcription factors (KLF5 and EEF1B2). Our study suggests that systematic analysis of mutation distribution in the tertiary protein structure can help identify cancer driver genes.

Systematic analysis of mutation distribution in three dimensional protein structures identifies cancer driver genes

PubMed Central

Fujimoto, Akihiro; Okada, Yukinori; Boroevich, Keith A.; Tsunoda, Tatsuhiko; Taniguchi, Hiroaki; Nakagawa, Hidewaki

2016-01-01

Protein tertiary structure determines molecular function, interaction, and stability of the protein, therefore distribution of mutation in the tertiary structure can facilitate the identification of new driver genes in cancer. To analyze mutation distribution in protein tertiary structures, we applied a novel three dimensional permutation test to the mutation positions. We analyzed somatic mutation datasets of 21 types of cancers obtained from exome sequencing conducted by the TCGA project. Of the 3,622 genes that had ≥3 mutations in the regions with tertiary structure data, 106 genes showed significant skew in mutation distribution. Known tumor suppressors and oncogenes were significantly enriched in these identified cancer gene sets. Physical distances between mutations in known oncogenes were significantly smaller than those of tumor suppressors. Twenty-three genes were detected in multiple cancers. Candidate genes with significant skew of the 3D mutation distribution included kinases (MAPK1, EPHA5, ERBB3, and ERBB4), an apoptosis related gene (APP), an RNA splicing factor (SF1), a miRNA processing factor (DICER1), an E3 ubiquitin ligase (CUL1) and transcription factors (KLF5 and EEF1B2). Our study suggests that systematic analysis of mutation distribution in the tertiary protein structure can help identify cancer driver genes. PMID:27225414

Oncogenic mutations in melanomas and benign melanocytic nevi of the female genital tract.

PubMed

Tseng, Diane; Kim, Julie; Warrick, Andrea; Nelson, Dylan; Pukay, Marina; Beadling, Carol; Heinrich, Michael; Selim, Maria Angelica; Corless, Christopher L; Nelson, Kelly

2014-08-01

The genetic heterogeneity of melanomas and melanocytic nevi of the female genital tract is poorly understood. We aim to characterize the frequency of mutations of the following genes: BRAF, NRAS, KIT, GNA11, and GNAQ in female genital tract melanomas. We also characterize the frequency of BRAF mutations in female genital tract melanomas compared with melanocytic nevi. Mutational screening was performed on the following female genital tract melanocytic neoplasms: 25 melanomas, 7 benign melanocytic nevi, and 4 atypical melanocytic nevi. Of the 25 female genital tract melanoma specimens queried, KIT mutations were detected in 4 (16.0%), NRAS mutations in 4 (16.0%), and BRAF mutations in 2 (8.0%) samples. Two of the tumors with KIT mutations harbored double mutations in the same exon. No GNAQ or GNA11 mutations were identified among 11 melanomas screened. BRAF V600E mutations were detected in 7 of 7 benign melanocytic genital nevi (100%) and 3 of 4 atypical genital nevi (75%). Our study is limited by the small sample size of this rare subset of melanomas. KIT, NRAS, and BRAF mutations are found in a subset of female genital tract melanomas. Screening for oncogenic mutations is important for developing and applying clinical therapies for melanomas of the female genital tract. Copyright © 2014 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

Aberrant status and clinicopathologic characteristic associations of 11 target genes in 1,321 Chinese patients with lung adenocarcinoma.

PubMed

Zhao, Mengnan; Zhan, Cheng; Li, Ming; Yang, Xiaodong; Yang, Xinyu; Zhang, Yong; Lin, Miao; Xia, Yifeng; Feng, Mingxiang; Wang, Qun

2018-01-01

The aberrant status of target genes and their associations with clinicopathologic characteristics are still unclear in primary lung adenocarcinoma. The common mutations and translocations of nine target genes were evaluated in 1,247 specimens of surgically-resected primary lung adenocarcinoma. Immunohistochemistry was used to analyze the expressions of programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) in 731 specimens. The frequency of the aberrations and their associations with clinicopathologic characteristics were analyzed. Overall, 952 (76.3%) of 1,247 patients harbored at least one target mutation or translocation: epidermal growth factor receptor ( EGFR ) (729, 58.5%), v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog ( KRAS ) (83, 6.7%), human epidermal growth factor receptor 2 ( HER2 ) (82, 6.6%), anaplastic lymphoma kinase ( ALK) (23, 1.8%), phosphoinositide-3-kinase catalytic alpha polypeptide ( PIK3CA ) (20, 1.6%), Ret proto-oncogene RET (15, 1.2%), ROS proto-oncogene 1 receptor tyrosine kinase ( ROS1 ) (12, 1.0%), B-raf proto-oncogene ( BRAF ) (9, 0.7%), neuroblastoma RAS viral (v-ras) oncogene homolog ( NRAS ) (3, 0.2%). Fourteen (1.9%) of 731 patients were PD-1 positive and 95 (13.0%) were PD-L1 positive in tumor cells. In men and smokers, there were more frequent KRAS mutations (both P<0.001) and PD-L1 positive tumors (P<0.001, P=0.005, respectively), and less frequent EGFR mutations (P=0.049, <0.001, respectively). In ground-glass opacity (GGO) or ground-glass nodules (GGN), there were more HER2 (P=0.033) but less EGFR (P=0.025) and PIK3CA mutations (P=0.012), and ALK translocations (P=0.014). EGFR (P<0.001), KRAS mutations (P=0.004) and PD-L1 positive tumors (P=0.046) were more frequent in older patients, while HER2 (P<0.001), ALK (P=0.005) and ROS1 aberrations (P=0.044) were less frequent. Invasive mucinous adenocarcinoma was significantly associated with KRAS and ALK aberrations (both P<0.001), while solid predominant adenocarcinoma was associated with ROS1 translocations (P=0.036) and PD-L1 expression (P<0.001). KRAS, HER2, and ALK aberrations were scarce in patients with EGFR mutations (all P<0.001), while PD-L1 positive tumors positively correlated with ALK translocations (P=0.031) and negatively correlated with HER2 mutations (P=0.019). Most patients with primary lung adenocarcinoma harbored target gene aberrations. The frequency of each alteration differed in patients depending on clinicopathologic characteristics.

Proto-oncogene activation in liver tumors of hepatocarcinogenesis-resistant strains of mice.

PubMed

Stanley, L A; Devereux, T R; Foley, J; Lord, P G; Maronpot, R R; Orton, T C; Anderson, M W

1992-12-01

Activation of the ras family of oncogenes occurs frequently in liver tumors of the B6C3F1 mouse, a strain which is highly sensitive to hepatocarcinogenesis. Many other mouse strains are much more resistant to hepatocarcinogenesis; the aim of this study was to determine the frequency and pattern of oncogene activation in spontaneous and chemically induced liver tumors of three such strains, the C57BL/6J, the C57BL/6 x DBA/2 F1 hybrid (B6D2F1) and the C57BL/6 x Balb/c F1 hybrid (B6BCF1). The C57BL/6, DBA/2 and Balb/c strains are all relatively resistant to spontaneous hepatocarcinogenesis (1.5-3.6% of animals develop liver tumors in 2 years); with regard to chemically induced hepatocarcinogenesis the Balb/c is highly resistant, the C57BL/6 has low susceptibility and the DBA/2 has low to moderate susceptibility. The nude mouse tumorigenicity assay was used to search for activated oncogenes in 15 C57BL/6J liver tumors induced by a single neonatal dose of vinyl carbamate (VC, 0.15 mumol/g body weight). Three tumors contained H-ras genes activated by point mutations at codon 61 and one contained a non-ras oncogene. The polymerase chain reaction and allele-specific oligonucleotide hybridization were used to study H-ras mutations in spontaneous and VC-induced tumors from all three strains of mice. The frequency of H-ras codon 61 mutations in tumors induced by 0.15 mumol/g body weight VC in the C57BL/6J mouse (5/37) was similar to that in spontaneous tumors (2/9); surprisingly, tumors induced by a lower dose of VC (0.03 mumol/g body weight) had a higher frequency of H-ras mutations (12/28). The frequencies of H-ras activation detected in VC (0.03 mumol/g body weight)-induced tumors from the two F1 hybrids studied differed markedly. Only one VC-induced B6BCF1 tumor contained a mutated H-ras gene (1/10), whereas the majority of B6D2F1 tumors contained such mutations (23/33). Several spontaneous B6D2F1 liver tumors contained H-ras codon 61 mutations (6/15). Thus, H-ras activation frequency does not determine susceptibility to hepatocarcinogenesis in inbred mice and their F1 hybrids, since a relatively high frequency of H-ras mutations was observed in two resistant strains and a low frequency was found in the other strain.

Genomic profiling of multiple sequentially acquired tumor metastatic sites from an “exceptional responder” lung adenocarcinoma patient reveals extensive genomic heterogeneity and novel somatic variants driving treatment response

PubMed Central

Biswas, Romi; Gao, Shaojian; Cultraro, Constance M.; Maity, Tapan K.; Venugopalan, Abhilash; Abdullaev, Zied; Shaytan, Alexey K.; Carter, Corey A.; Thomas, Anish; Rajan, Arun; Song, Young; Pitts, Stephanie; Chen, Kevin; Bass, Sara; Boland, Joseph; Hanada, Ken-Ichi; Chen, Jinqiu; Meltzer, Paul S.; Panchenko, Anna R.; Yang, James C.; Pack, Svetlana; Giaccone, Giuseppe; Schrump, David S.; Khan, Javed; Guha, Udayan

2016-01-01

We used next-generation sequencing to identify somatic alterations in multiple metastatic sites from an “exceptional responder” lung adenocarcinoma patient during his 7-yr course of ERBB2-directed therapies. The degree of heterogeneity was unprecedented, with ∼1% similarity between somatic alterations of the lung and lymph nodes. One novel translocation, PLAG1-ACTA2, present in both sites, up-regulated ACTA2 expression. ERBB2, the predominant driver oncogene, was amplified in both sites, more pronounced in the lung, and harbored an L869R mutation in the lymph node. Functional studies showed increased proliferation, migration, metastasis, and resistance to ERBB2-directed therapy because of L869R mutation and increased migration because of ACTA2 overexpression. Within the lung, a nonfunctional CDK12, due to a novel G879V mutation, correlated with down-regulation of DNA damage response genes, causing genomic instability, and sensitivity to chemotherapy. We propose a model whereby a subclone metastasized early from the primary site and evolved independently in lymph nodes. PMID:27900369

Structure of human POFUT1, its requirement in ligand-independent oncogenic Notch signaling, and functional effects of Dowling-Degos mutations

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMillan, Brian J.; Zimmerman, Brandon; Egan, Emily D.

Protein O-fucosyltransferase-1 (POFUT1), which transfers fucose residues to acceptor sites on serine and threonine residues of epidermal growth factor-like repeats of recipient proteins, is essential for Notch signal transduction in mammals. Here, we examine the consequences of POFUT1 loss on the oncogenic signaling associated with certain leukemia-associated mutations of human Notch1, report the structures of human POFUT1 in free and GDP-fucose bound states, and assess the effects of Dowling-Degos mutations on human POFUT1 function. CRISPR-mediated knockout of POFUT1 in U2OS cells suppresses both normal Notch1 signaling, and the ligand-independent signaling associated with leukemogenic mutations of Notch1. Normal and oncogenic signalingmore » are rescued by wild-type POFUT1 but rescue is impaired by an active-site R240A mutation. The overall structure of the human enzyme closely resembles that of the Caenorhabditis elegans protein, with an overall backbone RMSD of 0.93 Å, despite primary sequence identity of only 39% in the mature protein. GDP-fucose binding to the human enzyme induces limited backbone conformational movement, though the side chains of R43 and D244 reorient to make direct contact with the fucose moiety in the complex. The reported Dowling-Degos mutations of POFUT1, except for M262T, fail to rescue Notch1 signaling efficiently in the CRISPR-engineered POFUT1 -/- background. Together, these studies identify POFUT1 as a potential target for cancers driven by Notch1 mutations and provide a structural roadmap for its inhibition.« less

Validity of Targeted Next-Generation Sequencing in Routine Care for Identifying Clinically Relevant Molecular Profiles in Non-Small-Cell Lung Cancer: Results of a 2-Year Experience on 1343 Samples.

PubMed

Legras, Antoine; Barritault, Marc; Tallet, Anne; Fabre, Elizabeth; Guyard, Alice; Rance, Bastien; Digan, William; Pecuchet, Nicolas; Giroux-Leprieur, Etienne; Julie, Catherine; Jouveshomme, Stéphane; Duchatelle, Véronique; Giraudet, Véronique; Gibault, Laure; Cazier, Alain; Pastre, Jean; Le Pimpec-Barthes, Françoise; Laurent-Puig, Pierre; Blons, Hélène

2018-05-19

Theranostic assays are based on single-gene testing, but the ability of next-generation sequencing (NGS) to interrogate numerous genetic alterations will progressively replace single-gene assays. Although NGS was evaluated to screen for theranostic mutations, its usefulness in clinical practice on large series of samples remains to be demonstrated. NGS performance was assessed following guidelines. TaqMan probes and NGS were compared for their ability to detect EGFR and KRAS mutations, and NGS mutation profiles were analyzed on a large series of non-small-cell lung cancers (n = 1343). The R 2 correlation between expected and measured allelic ratio, using commercial samples, was >0.96. Mutation detection threshold was 2% for 10 ng of DNA input. κ Scores for TaqMan versus NGS were 0.99 (95% CI, 0.97-1.00) for EGFR and 0.98 (95% CI, 0.97-1.00) for KRAS after exclusion of rare EGFR (n = 40) and KRAS (n = 60) mutations. NGS identified 693 and 292 mutations in validated and potential oncogenic drivers, respectively. Significant associations were found between EGFR and PI3KCA or CTNNB1 and between KRAS and STK11. Potential oncogenic driver mutations or gene amplifications were more frequent in validated oncogenic driver nonmutated samples. This work is a proof of concept that targeted NGS is accessible in routine screening, including large screening, at reasonable cost. Clinical data should be collected and implemented in specific databases to make molecular data meaningful for direct patients' benefit. Copyright © 2018. Published by Elsevier Inc.

Treatment of NRAS-mutated advanced or metastatic melanoma: rationale, current trials and evidence to date

PubMed Central

Boespflug, Amélie; Caramel, Julie; Dalle, Stephane; Thomas, Luc

2017-01-01

The disease course of BRAF (v-raf murine sarcoma viral oncogene homolog B1)-mutant melanoma has been drastically improved by the arrival of targeted therapies. NRAS (neuroblastoma RAS viral oncogene homolog)-mutated melanoma represents 15–25% of all metastatic melanoma patients. It currently does not have an approved targeted therapy. Metastatic patients receive immune-based therapies as first-line treatments, then cytotoxic chemotherapy like carboplatin/paclitaxel (C/P), dacarbazine (DTIC) or temozolomide (TMZ) as a second-line treatment. We will review current preclinical and clinical developments in NRAS-mutated melanoma, and analyze ongoing clinical trials that are evaluating the benefit of different targeted and immune-based therapies, either tested as single agents or in combination, in NRAS-mutant melanoma. PMID:28717400

Oncogenic signaling by Kit tyrosine kinase occurs selectively on the Golgi apparatus in gastrointestinal stromal tumors

PubMed Central

Obata, Y; Horikawa, K; Takahashi, T; Akieda, Y; Tsujimoto, M; Fletcher, J A; Esumi, H; Nishida, T; Abe, R

2017-01-01

Gastrointestinal stromal tumors (GISTs) are caused by gain-of-function mutations in the Kit receptor tyrosine kinase. Most primary GIST patients respond to the Kit inhibitor imatinib, but this drug often becomes ineffective because of secondary mutations in the Kit kinase domain. The characteristic intracellular accumulation of imatinib-sensitive and -resistant Kit protein is well documented, but its relationship to oncogenic signaling remains unknown. Here, we show that in cancer tissue from primary GIST patients as well as in cell lines, mutant Kit accumulates on the Golgi apparatus, whereas normal Kit localizes to the plasma membrane (PM). In imatinib-resistant GIST with a secondary Kit mutation, Kit localizes predominantly on the Golgi apparatus. Both imatinib-sensitive and imatinib-resistant Kit (Kit(mut)) become fully auto-phosphorylated only on the Golgi and only if in a complex-glycosylated form. Kit(mut) accumulates on the Golgi during the early secretory pathway, but not after endocytosis. The aberrant kinase activity of Kit(mut) prevents its export from the Golgi to the PM. Furthermore, Kit(mut) on the Golgi signals and activates the phosphatidylinositol 3-kinase–Akt (PI3K–Akt) pathway, signal transducer and activator of transcription 5 (STAT5), and the Mek–Erk pathway. Blocking the biosynthetic transport of Kit(mut) to the Golgi from the endoplasmic reticulum inhibits oncogenic signaling. PM localization of Kit(mut) is not required for its signaling. Activation of Src-family tyrosine kinases on the Golgi is essential for oncogenic Kit signaling. These results suggest that the Golgi apparatus serves as a platform for oncogenic Kit signaling. Our study demonstrates that Kit(mut)’s pathogenicity is related to its mis-localization, and may offer a new strategy for treating imatinib-resistant GISTs. PMID:28192400

Consistency and reproducibility of next-generation sequencing and other multigene mutational assays: A worldwide ring trial study on quantitative cytological molecular reference specimens.

PubMed

Malapelle, Umberto; Mayo-de-Las-Casas, Clara; Molina-Vila, Miguel A; Rosell, Rafael; Savic, Spasenija; Bihl, Michel; Bubendorf, Lukas; Salto-Tellez, Manuel; de Biase, Dario; Tallini, Giovanni; Hwang, David H; Sholl, Lynette M; Luthra, Rajyalakshmi; Weynand, Birgit; Vander Borght, Sara; Missiaglia, Edoardo; Bongiovanni, Massimo; Stieber, Daniel; Vielh, Philippe; Schmitt, Fernando; Rappa, Alessandra; Barberis, Massimo; Pepe, Francesco; Pisapia, Pasquale; Serra, Nicola; Vigliar, Elena; Bellevicine, Claudio; Fassan, Matteo; Rugge, Massimo; de Andrea, Carlos E; Lozano, Maria D; Basolo, Fulvio; Fontanini, Gabriella; Nikiforov, Yuri E; Kamel-Reid, Suzanne; da Cunha Santos, Gilda; Nikiforova, Marina N; Roy-Chowdhuri, Sinchita; Troncone, Giancarlo

2017-08-01

Molecular testing of cytological lung cancer specimens includes, beyond epidermal growth factor receptor (EGFR), emerging predictive/prognostic genomic biomarkers such as Kirsten rat sarcoma viral oncogene homolog (KRAS), neuroblastoma RAS viral [v-ras] oncogene homolog (NRAS), B-Raf proto-oncogene, serine/threonine kinase (BRAF), and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA). Next-generation sequencing (NGS) and other multigene mutational assays are suitable for cytological specimens, including smears. However, the current literature reflects single-institution studies rather than multicenter experiences. Quantitative cytological molecular reference slides were produced with cell lines designed to harbor concurrent mutations in the EGFR, KRAS, NRAS, BRAF, and PIK3CA genes at various allelic ratios, including low allele frequencies (AFs; 1%). This interlaboratory ring trial study included 14 institutions across the world that performed multigene mutational assays, from tissue extraction to data analysis, on these reference slides, with each laboratory using its own mutation analysis platform and methodology. All laboratories using NGS (n = 11) successfully detected the study's set of mutations with minimal variations in the means and standard errors of variant fractions at dilution points of 10% (P = .171) and 5% (P = .063) despite the use of different sequencing platforms (Illumina, Ion Torrent/Proton, and Roche). However, when mutations at a low AF of 1% were analyzed, the concordance of the NGS results was low, and this reflected the use of different thresholds for variant calling among the institutions. In contrast, laboratories using matrix-assisted laser desorption/ionization-time of flight (n = 2) showed lower concordance in terms of mutation detection and mutant AF quantification. Quantitative molecular reference slides are a useful tool for monitoring the performance of different multigene mutational assays, and this could lead to better standardization of molecular cytopathology procedures. Cancer Cytopathol 2017;125:615-26. © 2017 American Cancer Society. © 2017 American Cancer Society.

The mucin MUC4 is a transcriptional and post-transcriptional target of K-ras oncogene in pancreatic cancer. Implication of MAPK/AP-1, NF-κB and RalB signaling pathways.

PubMed

Vasseur, Romain; Skrypek, Nicolas; Duchêne, Belinda; Renaud, Florence; Martínez-Maqueda, Daniel; Vincent, Audrey; Porchet, Nicole; Van Seuningen, Isabelle; Jonckheere, Nicolas

2015-12-01

The membrane-bound mucinMUC4 is a high molecularweight glycoprotein frequently deregulated in cancer. In pancreatic cancer, one of the most deadly cancers in occidental countries, MUC4 is neo-expressed in the preneoplastic stages and thereafter is involved in cancer cell properties leading to cancer progression and chemoresistance. K-ras oncogene is a small GTPase of the RAS superfamily, highly implicated in cancer. K-ras mutations are considered as an initiating event of pancreatic carcinogenesis and K-ras oncogenic activities are necessary components of cancer progression. However, K-ras remains clinically undruggable. Targeting early downstream K-ras signaling in cancer may thus appear as an interesting strategy and MUC4 regulation by K-ras in pancreatic carcinogenesis remains unknown. Using the Pdx1-Cre; LStopL-K-rasG12D mouse model of pancreatic carcinogenesis, we show that the in vivo early neo-expression of the mucin Muc4 in pancreatic intraepithelial neoplastic lesions (PanINs) induced by mutated K-ras is correlated with the activation of ERK, JNK and NF-κB signaling pathways. In vitro, transfection of constitutively activated K-rasG12V in pancreatic cancer cells led to the transcriptional upregulation of MUC4. This activation was found to be mediated at the transcriptional level by AP-1 and NF-κB transcription factors via MAPK, JNK and NF-κB pathways and at the posttranscriptional level by a mechanism involving the RalB GTPase. Altogether, these results identify MUC4 as a transcriptional and post-transcriptional target of K-ras in pancreatic cancer. This opens avenues in developing new approaches to target the early steps of this deadly cancer.

Pirin Inhibits Cellular Senescence in Melanocytic Cells

PubMed Central

Licciulli, Silvia; Luise, Chiara; Scafetta, Gaia; Capra, Maria; Giardina, Giuseppina; Nuciforo, Paolo; Bosari, Silvano; Viale, Giuseppe; Mazzarol, Giovanni; Tonelli, Chiara; Lanfrancone, Luisa; Alcalay, Myriam

2011-01-01

Cellular senescence has been widely recognized as a tumor suppressing mechanism that acts as a barrier to cancer development after oncogenic stimuli. A prominent in vivo model of the senescence barrier is represented by nevi, which are composed of melanocytes that, after an initial phase of proliferation induced by activated oncogenes (most commonly BRAF), are blocked in a state of cellular senescence. Transformation to melanoma occurs when genes involved in controlling senescence are mutated or silenced and cells reacquire the capacity to proliferate. Pirin (PIR) is a highly conserved nuclear protein that likely functions as a transcriptional regulator whose expression levels are altered in different types of tumors. We analyzed the expression pattern of PIR in adult human tissues and found that it is expressed in melanocytes and has a complex pattern of regulation in nevi and melanoma: it is rarely detected in mature nevi, but is expressed at high levels in a subset of melanomas. Loss of function and overexpression experiments in normal and transformed melanocytic cells revealed that PIR is involved in the negative control of cellular senescence and that its expression is necessary to overcome the senescence barrier. Our results suggest that PIR may have a relevant role in melanoma progression. PMID:21514450

Frequencies and prognostic impact of RAS mutations in MLL-rearranged acute lymphoblastic leukemia in infants

PubMed Central

Driessen, Emma M.C.; van Roon, Eddy H.J.; Spijkers-Hagelstein, Jill A.P.; Schneider, Pauline; de Lorenzo, Paola; Valsecchi, Maria Grazia; Pieters, Rob; Stam, Ronald W.

2013-01-01

Acute lymphoblastic leukemia in infants represents an aggressive malignancy associated with a high incidence (approx. 80%) of translocations involving the Mixed Lineage Leukemia (MLL) gene. Attempts to mimic Mixed Lineage Leukemia fusion driven leukemogenesis in mice raised the question whether these fusion proteins require secondary hits. RAS mutations are suggested as candidates. Earlier results on the incidence of RAS mutations in Mixed Lineage Leukemia-rearranged acute lymphoblastic leukemia are inconclusive. Therefore, we studied frequencies and relation with clinical parameters of RAS mutations in a large cohort of infant acute lymphoblastic leukemia patients. Using conventional sequencing analysis, we screened neuroblastoma RAS viral (v-ras) oncogene homolog gene (NRAS), v-Ki-ras Kirsten rat sarcoma viral oncogene homolog gene (KRAS), and v-raf murine sarcoma viral oncogene homolog B1 gene (BRAF) for mutations in a large cohort (n=109) of infant acute lymphoblastic leukemia patients and studied the mutations in relation to several clinical parameters, and in relation to Homeobox gene A9 expression and the presence of ALL1 fused gene 4-Mixed Lineage Leukemia (AF4-MLL). Mutations were detected in approximately 14% of all cases, with a higher frequency of approximately 24% in t(4;11)-positive patients (P=0.04). Furthermore, we identified RAS mutations as an independent predictor (P=0.019) for poor outcome in Mixed Lineage Leukemia-rearranged infant acute lymphoblastic leukemia, with a hazard ratio of 3.194 (95% confidence interval (CI):1.211–8.429). Also, RAS-mutated infants have higher white blood cell counts at diagnosis (P=0.013), and are more resistant to glucocorticoids in vitro (P<0.05). Finally, we demonstrate that RAS mutations, and not the lack of Homeobox gene A9 expression nor the expression of AF4-MLL are associated with poor outcome in t(4;11)-rearranged infants. We conclude that the presence of RAS mutations in Mixed Lineage Leukemia-rearranged infant acute lymphoblastic leukemia is an independent predictor for a poor outcome. Therefore, future risk-stratification based on abnormal RAS-pathway activation and RAS-pathway inhibition could be beneficial in RAS-mutated infant acute lymphoblastic leukemia patients. PMID:23403319

Analysis of the oncogene BRAF mutation and the correlation of the expression of wild-type BRAF and CREB1 in endometriosis

PubMed Central

Lv, Xiao; Ma, Yue; Long, Zaiqiu

2018-01-01

B-Raf proto-oncogene, serine/threonine kinase (BRAF) has previously been identified as a candidate target gene in endometriosis. Wild-type and mutated BRAF serve important roles in different diseases. The aim of the present study was to explore BRAF mutation, the mRNA and protein expression of wild-type BRAF (wtBRAF) in endometriosis, and the association between the expression levels of wtBRAF and the predicted transcription factor cAMP responsive element binding protein 1 (CREB1). In the present study, BRAF mutation was detected using Sanger sequencing among 30 ectopic and matched eutopic endometrium samples of patients with endometriosis as well as 25 normal endometrium samples, and no BRAF mutation was detected in exons 11 or 15. A region of ~2,000 bp upstream of the BRAF gene was then screened using NCBI and UCSC databases, and CREB1 was identified as a potential transcription factor of BRAF by analysis with the JASPAR and the TRANSFAC databases. Quantitative polymerase chain reaction was used to analysis the mRNA expression levels of wtBRAF and CREB1, and the corresponding protein expression levels were evaluated using immunohistochemistry and western blot analysis. The results revealed that the mRNA and protein expression levels of wtBRAF and CREB1 were significantly upregulated in the eutopic endometrial tissues of patients with endometriosis compared with normal endometrial tissues (P<0.05) and no significant difference in wtBRAF and CREB1 levels was detected between the ectopic and eutopic endometrium (P>0.05). In addition, correlation analysis revealed that the protein expression of CREB1 was positively correlated with the transcript level and protein expression of wtBRAF. It is reasonable to speculate that CREB1 may activate the transcription of wtBRAF through directly binding to its promoter, increasing BRAF expression and regulating the cell proliferation, migration and invasion of endometriosis. PMID:29286077

RAG-mediated recombination is the predominant driver of oncogenic rearrangement in ETV6-RUNX1 acute lymphoblastic leukemia

PubMed Central

Papaemmanuil, Elli; Rapado, Inmaculada; Li, Yilong; Potter, Nicola E; Wedge, David C; Tubio, Jose; Alexandrov, Ludmil B; Van Loo, Peter; Cooke, Susanna L; Marshall, John; Martincorena, Inigo; Hinton, Jonathan; Gundem, Gunes; van Delft, Frederik W; Nik-Zainal, Serena; Jones, David R; Ramakrishna, Manasa; Titley, Ian; Stebbings, Lucy; Leroy, Catherine; Menzies, Andrew; Gamble, John; Robinson, Ben; Mudie, Laura; Raine, Keiran; O’Meara, Sarah; Teague, Jon W; Butler, Adam P; Cazzaniga, Giovanni; Biondi, Andrea; Zuna, Jan; Kempski, Helena; Muschen, Markus; Ford, Anthony M; Stratton, Michael R; Greaves, Mel; Campbell, Peter J

2014-01-01

The ETV6-RUNX1 fusion gene, found in 25% of childhood acute lymphoblastic leukemia (ALL), is acquired in utero but requires additional somatic mutations for overt leukemia. We used exome and low-coverage whole-genome sequencing to characterize secondary events associated with leukemic transformation. RAG-mediated deletions emerge as the dominant mutational process, characterized by recombination signal sequence motifs near the breakpoints; incorporation of non-templated sequence at the junction; ~30-fold enrichment at promoters and enhancers of genes actively transcribed in B-cell development and an unexpectedly high ratio of recurrent to non-recurrent structural variants. Single cell tracking shows that this mechanism is active throughout leukemic evolution with evidence of localized clustering and re-iterated deletions. Integration of point mutation and rearrangement data identifies ATF7IP and MGA as two new tumor suppressor genes in ALL. Thus, a remarkably parsimonious mutational process transforms ETV6-RUNX1 lymphoblasts, targeting the promoters, enhancers and first exons of genes that normally regulate B-cell differentiation. PMID:24413735

Histone H3.3 mutations drive paediatric glioblastoma through upregulation of MYCN

PubMed Central

Bjerke, Lynn; Mackay, Alan; Nandhabalan, Meera; Burford, Anna; Jury, Alexa; Popov, Sergey; Bax, Dorine A; Carvalho, Diana; Taylor, Kathryn R; Vinci, Maria; Bajrami, Ilirjana; McGonnell, Imelda M; Lord, Christopher J; Reis, Rui M; Hargrave, Darren; Ashworth, Alan; Workman, Paul; Jones, Chris

2013-01-01

Glioblastomas of children and young adults have a median survival of only 12-15months and are clinically and biologically distinct from histologically similar cancers in older adults1. They are defined by highly specific mutations in the gene encoding the histone H3.3 variant H3F3A2, occurring either at or close to key residues marked by methylation for regulation of transcription – K27 and G34. Here we show that the cerebral hemispheric-specific G34 mutation drives a distinct expression signature through differential genomic binding of the K36 trimethylation mark (H3K36me3). The transcriptional program induced recapitulates that of the developing forebrain, and involves numerous markers of stem cell maintenance, cell fate decisions and self-renewal. Critically, H3F3A G34 mutations cause profound upregulation of MYCN, a potent oncogene which is causative of glioblastomas when expressed in the correct developmental context. This driving aberration is selectively targetable in this patient population by inhibiting kinases responsible for stabilisation of the protein. PMID:23539269

Interplay of autophagy, receptor tyrosine kinase signalling and endocytic trafficking

PubMed Central

Fraser, Jane; Cabodevilla, Ainara G.; Simpson, Joanne; Gammoh, Noor

2017-01-01

Vesicular trafficking events play key roles in the compartmentalization and proper sorting of cellular components. These events have crucial roles in sensing external signals, regulating protein activities and stimulating cell growth or death decisions. Although mutations in vesicle trafficking players are not direct drivers of cellular transformation, their activities are important in facilitating oncogenic pathways. One such pathway is the sensing of external stimuli and signalling through receptor tyrosine kinases (RTKs). The regulation of RTK activity by the endocytic pathway has been extensively studied. Compelling recent studies have begun to highlight the association between autophagy and RTK signalling. The influence of this interplay on cellular status and its relevance in disease settings will be discussed here. PMID:29233871

p53 mutations promote proteasomal activity.

PubMed

Oren, Moshe; Kotler, Eran

2016-07-27

p53 mutations occur very frequently in human cancer. Besides abrogating the tumour suppressive functions of wild-type p53, many of those mutations also acquire oncogenic gain-of-function activities. Augmentation of proteasome activity is now reported as a common gain-of-function mechanism shared by different p53 mutants, which promotes cancer resistance to proteasome inhibitors.

p53 regulates cytoskeleton remodeling to suppress tumor progression.

PubMed

Araki, Keigo; Ebata, Takahiro; Guo, Alvin Kunyao; Tobiume, Kei; Wolf, Steven John; Kawauchi, Keiko

2015-11-01

Cancer cells possess unique characteristics such as invasiveness, the ability to undergo epithelial-mesenchymal transition, and an inherent stemness. Cell morphology is altered during these processes and this is highly dependent on actin cytoskeleton remodeling. Regulation of the actin cytoskeleton is, therefore, important for determination of cell fate. Mutations within the TP53 (tumor suppressor p53) gene leading to loss or gain of function (GOF) of the protein are often observed in aggressive cancer cells. Here, we highlight the roles of p53 and its GOF mutants in cancer cell invasion from the perspective of the actin cytoskeleton; in particular its reorganization and regulation by cell adhesion molecules such as integrins and cadherins. We emphasize the multiple functions of p53 in the regulation of actin cytoskeleton remodeling in response to the extracellular microenvironment, and oncogene activation. Such an approach provides a new perspective in the consideration of novel targets for anti-cancer therapy.

Pre-malignant lymphoid cells arise from hematopoietic stem/progenitor cells in chronic lymphocytic leukemia.

PubMed

Kikushige, Yoshikane; Miyamoto, Toshihiro

2015-11-01

Human malignancies progress through a multistep process that includes the development of critical somatic mutations over the clinical course. Recent novel findings have indicated that hematopoietic stem cells (HSCs), which have the potential to self-renew and differentiate into multilineage hematopoietic cells, are an important cellular target for the accumulation of critical somatic mutations in hematological malignancies and play a central role in myeloid malignancy development. In contrast to myeloid malignancies, mature lymphoid malignancies, such as chronic lymphocytic leukemia (CLL), are thought to originate directly from differentiated mature lymphocytes; however, recent compelling data have shown that primitive HSCs and hematopoietic progenitor cells contribute to the pathogenesis of mature lymphoid malignancies. Several representative mutations of hematological malignancies have been identified within the HSCs of CLL and lymphoma patients, indicating that the self-renewing long-lived fraction of HSCs can serve as a reservoir for the development of oncogenic events. Novel mice models have been established as human mature lymphoma models, in which specific oncogenic events target the HSCs and immature progenitor cells. These data collectively suggest that HSCs can be the cellular target involved in the accumulation of oncogenic events in the pathogenesis of mature lymphoid and myeloid malignancies.

Oncogenic MicroRNA-20a is downregulated by the HIF-1α/c-MYC pathway in IDH1 R132H-mutant glioma.

PubMed

Xu, Qingfu; Ahmed, A Karim; Zhu, Yan; Wang, Kimberly; Lv, Shengqing; Li, Yunqing; Jiang, Yugang

2018-05-23

Mutations in the isocitrate dehydrogenase 1 (IDH1) gene have been identified as one of the earliest events in gliomagenesis, occurring in over 70% of low grade gliomas and are present in the vast majority of secondary glioblastoma (GBM) that develop from these low-grade lesions. The aim of this study was to investigate whether the IDH1 R132H mutation influences the expression of oncogenic miR-20a and shed light on the underlying molecular mechanisms. The findings of the current study demonstrate presence of the IDH1 R132H mutation in primary human glioblastoma cell lines with upregulated HIF-1α expression, downregulating c-MYC activity and resulting in a consequential decrease in miR-20a, which is responsible for cell proliferation and resistance to standard temozolomide treatment. Elucidating the mechanism of oncogenic miR-20a activity introduces its role among well-established signaling pathways (i.e. HIF/c-MYC) and may be a meaningful prognostic biomarker or target for novel therapies among patients with IDH1-mutant glioma. Copyright © 2018 Elsevier Inc. All rights reserved.

Chromatin-bound IκBα regulates a subset of polycomb target genes in differentiation and cancer.

PubMed

Mulero, María Carmen; Ferres-Marco, Dolors; Islam, Abul; Margalef, Pol; Pecoraro, Matteo; Toll, Agustí; Drechsel, Nils; Charneco, Cristina; Davis, Shelly; Bellora, Nicolás; Gallardo, Fernando; López-Arribillaga, Erika; Asensio-Juan, Elena; Rodilla, Verónica; González, Jessica; Iglesias, Mar; Shih, Vincent; Mar Albà, M; Di Croce, Luciano; Hoffmann, Alexander; Miyamoto, Shigeki; Villà-Freixa, Jordi; López-Bigas, Nuria; Keyes, William M; Domínguez, María; Bigas, Anna; Espinosa, Lluís

2013-08-12

IκB proteins are the primary inhibitors of NF-κB. Here, we demonstrate that sumoylated and phosphorylated IκBα accumulates in the nucleus of keratinocytes and interacts with histones H2A and H4 at the regulatory region of HOX and IRX genes. Chromatin-bound IκBα modulates Polycomb recruitment and imparts their competence to be activated by TNFα. Mutations in the Drosophila IκBα gene cactus enhance the homeotic phenotype of Polycomb mutants, which is not counteracted by mutations in dorsal/NF-κB. Oncogenic transformation of keratinocytes results in cytoplasmic IκBα translocation associated with a massive activation of Hox. Accumulation of cytoplasmic IκBα was found in squamous cell carcinoma (SCC) associated with IKK activation and HOX upregulation. Copyright © 2013 Elsevier Inc. All rights reserved.

Dynamic regulation of GDP binding to G proteins revealed by magnetic field-dependent NMR relaxation analyses

PubMed Central

Toyama, Yuki; Kano, Hanaho; Mase, Yoko; Yokogawa, Mariko; Osawa, Masanori; Shimada, Ichio

2017-01-01

Heterotrimeric guanine-nucleotide-binding proteins (G proteins) serve as molecular switches in signalling pathways, by coupling the activation of cell surface receptors to intracellular responses. Mutations in the G protein α-subunit (Gα) that accelerate guanosine diphosphate (GDP) dissociation cause hyperactivation of the downstream effector proteins, leading to oncogenesis. However, the structural mechanism of the accelerated GDP dissociation has remained unclear. Here, we use magnetic field-dependent nuclear magnetic resonance relaxation analyses to investigate the structural and dynamic properties of GDP bound Gα on a microsecond timescale. We show that Gα rapidly exchanges between a ground-state conformation, which tightly binds to GDP and an excited conformation with reduced GDP affinity. The oncogenic D150N mutation accelerates GDP dissociation by shifting the equilibrium towards the excited conformation. PMID:28223697

Dynamic regulation of GDP binding to G proteins revealed by magnetic field-dependent NMR relaxation analyses.

PubMed

Toyama, Yuki; Kano, Hanaho; Mase, Yoko; Yokogawa, Mariko; Osawa, Masanori; Shimada, Ichio

2017-02-22

Heterotrimeric guanine-nucleotide-binding proteins (G proteins) serve as molecular switches in signalling pathways, by coupling the activation of cell surface receptors to intracellular responses. Mutations in the G protein α-subunit (Gα) that accelerate guanosine diphosphate (GDP) dissociation cause hyperactivation of the downstream effector proteins, leading to oncogenesis. However, the structural mechanism of the accelerated GDP dissociation has remained unclear. Here, we use magnetic field-dependent nuclear magnetic resonance relaxation analyses to investigate the structural and dynamic properties of GDP bound Gα on a microsecond timescale. We show that Gα rapidly exchanges between a ground-state conformation, which tightly binds to GDP and an excited conformation with reduced GDP affinity. The oncogenic D150N mutation accelerates GDP dissociation by shifting the equilibrium towards the excited conformation.

Epigenetic regulation of immune checkpoints: another target for cancer immunotherapy?

PubMed

Ali, Mahmoud A; Matboli, Marwa; Tarek, Marwa; Reda, Maged; Kamal, Kamal M; Nouh, Mahmoud; Ashry, Ahmed M; El-Bab, Ahmed Fath; Mesalam, Hend A; Shafei, Ayman El-Sayed; Abdel-Rahman, Omar

2017-01-01

Epigenetic changes in oncogenes and tumor-suppressor genes contribute to carcinogenesis. Understanding the epigenetic and genetic components of tumor immune evasion is crucial. Few cancer genetic mutations have been linked to direct correlations with immune evasion. Studies on the epigenetic modulation of the immune checkpoints have revealed a critical interaction between epigenetic and immune modulation. Epigenetic modifiers can activate many silenced genes. Some of them are immune checkpoints regulators that turn on immune responses and others turn them off resulting in immune evasion. Many forms of epigenetic inheritance mechanisms may play a role in regulation of immune checkpoints including: covalent modifications, noncoding RNA and histone modifications. In this review, we will show how the potential interaction between epigenetic and immune modulation may lead to new approaches for specific epigenome/immunome-targeted therapies for cancer.

Mutational analysis of PI3K/AKT and RAS/RAF pathway activation in malignant salivary gland tumours with a new mutation of PIK3CA.

PubMed

Shalmon, B; Drendel, M; Wolf, M; Hirshberg, A; Cohen, Y

2016-06-01

The phosphoinositide 3-kinase (PIK3)/v-akt murine thymoma (AKT) oncogene pathway and the RAS/RAF pathway are involved in regulating the signalling of multiple biological processes, including apoptosis, metabolism, cell proliferation, and cell growth. Mutations in the genes within these pathways are frequently found in several tumours. The aim of this study was to investigate the frequency of mutations in the PIK3CA, BRAF, and KRAS genes in cases of malignant salivary gland tumours. Mutational analysis of the PIK3CA, KRAS, and BRAF genes was performed by direct sequencing of material from 21 patients with malignant salivary gland tumours who underwent surgery between 1992 and 2001. No mutations were found in the KRAS exon 2, BRAF exon 15, or PIK3CA exon 9 genes. However, an unpublished mutation of the PIK3CA gene in exon 20 (W1051 stop mutation) was found in one case of adenocarcinoma NOS. The impact of this mutation on the biological behaviour of the tumour has yet to be explored, however the patient with adenocarcinoma NOS harbouring this mutation has survived for over 20 years following surgery despite a high stage at presentation. Further studies with more homogeneous patient cohorts are needed to address whether this mutation reflects a different clinical presentation and may benefit from targeted treatment strategies. Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Oncogenic and RASopathy-associated K-RAS mutations relieve membrane-dependent occlusion of the effector-binding site.

PubMed

Mazhab-Jafari, Mohammad T; Marshall, Christopher B; Smith, Matthew J; Gasmi-Seabrook, Geneviève M C; Stathopulos, Peter B; Inagaki, Fuyuhiko; Kay, Lewis E; Neel, Benjamin G; Ikura, Mitsuhiko

2015-05-26

K-RAS4B (Kirsten rat sarcoma viral oncogene homolog 4B) is a prenylated, membrane-associated GTPase protein that is a critical switch for the propagation of growth factor signaling pathways to diverse effector proteins, including rapidly accelerated fibrosarcoma (RAF) kinases and RAS-related protein guanine nucleotide dissociation stimulator (RALGDS) proteins. Gain-of-function KRAS mutations occur frequently in human cancers and predict poor clinical outcome, whereas germ-line mutations are associated with developmental syndromes. However, it is not known how these mutations affect K-RAS association with biological membranes or whether this impacts signal transduction. Here, we used solution NMR studies of K-RAS4B tethered to nanodiscs to investigate lipid bilayer-anchored K-RAS4B and its interactions with effector protein RAS-binding domains (RBDs). Unexpectedly, we found that the effector-binding region of activated K-RAS4B is occluded by interaction with the membrane in one of the NMR-observable, and thus highly populated, conformational states. Binding of the RAF isoform ARAF and RALGDS RBDs induced marked reorientation of K-RAS4B from the occluded state to RBD-specific effector-bound states. Importantly, we found that two Noonan syndrome-associated mutations, K5N and D153V, which do not affect the GTPase cycle, relieve the occluded orientation by directly altering the electrostatics of two membrane interaction surfaces. Similarly, the most frequent KRAS oncogenic mutation G12D also drives K-RAS4B toward an exposed configuration. Further, the D153V and G12D mutations increase the rate of association of ARAF-RBD with lipid bilayer-tethered K-RAS4B. We revealed a mechanism of K-RAS4B autoinhibition by membrane sequestration of its effector-binding site, which can be disrupted by disease-associated mutations. Stabilizing the autoinhibitory interactions between K-RAS4B and the membrane could be an attractive target for anticancer drug discovery.

Comprehensive investigation of oncogenic driver mutations in Chinese non-small cell lung cancer patients.

PubMed

Wang, Rui; Zhang, Yang; Pan, Yunjian; Li, Yuan; Hu, Haichuan; Cai, Deng; Li, Hang; Ye, Ting; Luo, Xiaoyang; Zhang, Yiliang; Li, Bin; Shen, Lei; Sun, Yihua; Chen, Haiquan

2015-10-27

To determine the frequency of driver mutations in Chinese non-small cell lung cancer (NSCLC) patients. Comprehensive mutational analysis was performed in 1356 lung adenocarcinoma, 503 squamous cell carcinoma, 57 adenosquamous lung carcinoma, 19 large cell carcinoma and 8 sarcomatoid carcinoma. The effect of EGFR tyrosine kinase inhibitors (TKIs) on EGFR-mutated lung adenocarcinoma patients after disease recurrence was investigated. Mutations in EGFR kinase domain, HER2 kinase domain, KRAS, BRAF, ALK, ROS1 and RET were mutually exclusive. In lung adenocarcinoma cases "pan-negative" for the seven above-mentioned driver mutations, we also detected two oncogenic EGFR extracellular domain mutations (A289D and R324L), two HER2 extracellular and transmembrane domain mutations (S310Y and V659E), one ARAF S214C mutation and two CD74-NRG1 fusions. Six (1.2%) FGFR3 activating mutations were identified in lung squamous cell carcinoma (five S249C and one R248C). There were three (15.8%) EGFR mutations and four (21.1%) KRAS mutations in large cell carcinoma. Three (37.5%) KRAS mutations were detected in sarcomatoid carcinoma. In EGFR-mutated lung adenocarcinoma patients who experienced disease recurrence, treatment with EGFR TKIs was an independent predictor of better overall survival (HR = 0.299, 95% CI: 0.172-0.519, P < 0.001). We determined the frequency of driver mutations in a large series of Chinese NSCLC patients. EGFR TKIs might improve the survival outcomes of EGFR-mutated lung adenocarcinoma patients who experienced disease recurrence.

G protein abnormalities in pituitary adenomas.

PubMed

Spada, A; Lania, A; Ballarè, E

1998-07-25

It has been demonstrated that the majority of secreting and nonsecreting adenomas is monoclonal in origin suggesting that these neoplasia arise from the replication of a single mutated cell, in which growth advantage results from either activation of protooncogenes or inactivation of antioncogenes. Although a large number of genes has been screened for mutations, only few genetic abnormalities have been found in pituitary tumors such as allelic deletion of chromosome 11q13 where the MEN-1 gene has been localised, and mutations in the gene encoding the alpha subunit of the stimulatory Gs and Gi2 protein. These mutations constitutively activate the alpha subunit of the Gs and Gi2 protein by inhibiting their intrinsic GTPase activity. Both Gs alpha and Gi2alpha can be considered products of protooncogenes (gsp and gip2, respectively) since gain of function mutations that activate mitogenic signals have been recognized in human tumors. Gsp oncogene is found in 30-40% of GH-secreting adenomas, in a low percentage of nonfunctioning and ACTH-secreting pituitary adenomas, in toxic thyroid adenomas and differentiated thyroid carcinomas. The same mutations, occurred early in embriogenesis, have been also identified in tissues from patients affected with the McCune Albright syndrome. These mutations result in an increased cAMP production and in the subsequent overactivation of specific pathways involved in both cell growth and specific programmes of cell differentiation. By consequence, the endocrine tumors expressing gsp oncogene retain differentiated functions. The gip2 oncogene has been identified in about 10% of nonfunctioning pituitary adenomas, in tumors of the ovary and the adrenal cortex. However, it remains to be established whether Gi proteins activate mitogenic signals in pituitary cells. Since Gi proteins are involved in mediating the effect of inhibitory neurohormones on intracellular effectors, it has been proposed that in pituitary tumors the low expression of these proteins, particularly Gi1-3alpha, may contribute to uncontrolled pituitary cells growth by preventing the transduction of inhibitory signals. While by in vitro mutagenesis it has been demonstrated that activated mutant of Gq alpha, G12alpha, G13alpha and Gz alpha are fully oncogenic, it remains to be proved whether or not these abnormalities might naturally occur in human tumors and, in particular, in pituitary adenomas.

Identification of a novel missense mutation of MAF in a Japanese family with congenital cataract by whole exome sequencing: a clinical report and review of literature.

PubMed

Narumi, Yoko; Nishina, Sachiko; Tokimitsu, Motoharu; Aoki, Yoko; Kosaki, Rika; Wakui, Keiko; Azuma, Noriyuki; Murata, Toshinori; Takada, Fumio; Fukushima, Yoshimitsu; Kosho, Tomoki

2014-05-01

Congenital cataracts are the most important cause of severe visual impairment in infants. Genetic factors contribute to the disease development and 29 genes are known to cause congenital cataracts. Identifying the genetic cause of congenital cataracts can be difficult because of genetic heterogeneity. V-maf avian musculoaponeurotic fibrosarcoma oncogene homolog (MAF) encodes a basic region/leucine zipper transcription factor that plays a key role as a regulator of embryonic lens fiber cell development. MAF mutations have been reported to cause juvenile-onset pulverulent cataract, microcornea, iris coloboma, and other anterior segment dysgenesis. We report on six patients in a family who have congenital cataracts were identified MAF mutation by whole exome sequencing (WES). The heterozygous MAF mutation Q303L detected in the present family occurs in a well conserved glutamine residue at the basic region of the DNA-binding domain. All affected members showed congenital cataracts. Three of the six members showed microcornea and one showed iris coloboma. Congenital cataracts with MAF mutation exhibited phenotypically variable cataracts within the family. Review of the patients with MAF mutations supports the notion that congenital cataracts caused by MAF mutations could be accompanied by microcornea and/or iris coloboma. WES is a useful tool for detecting disease-causing mutations in patients with genetically heterogeneous conditions. © 2014 Wiley Periodicals, Inc.

MNK1/2 inhibition limits oncogenicity and metastasis of KIT-mutant melanoma

PubMed Central

Zhan, Yao; Guo, Jun; Yang, William; Goncalves, Christophe; Rzymski, Tomasz; Dreas, Agnieszka; Żyłkiewicz, Eliza; Mikulski, Maciej; Brzózka, Krzysztof; Golas, Aniela; Kong, Yan; Ma, Meng; Huang, Fan; Huor, Bonnie; Guo, Qianyu; da Silva, Sabrina Daniela; Torres, Jose; Cai, Yutian; Topisirovic, Ivan; Su, Jie; Bijian, Krikor; Alaoui-Jamali, Moulay A.; Huang, Sidong; Journe, Fabrice; Ghanem, Ghanem E.; Miller, Wilson H.

2017-01-01

Melanoma can be stratified into unique subtypes based on distinct pathologies. The acral/mucosal melanoma subtype is characterized by aberrant and constitutive activation of the proto-oncogene receptor tyrosine kinase C-KIT, which drives tumorigenesis. Treatment of these melanoma patients with C-KIT inhibitors has proven challenging, prompting us to investigate the downstream effectors of the C-KIT receptor. We determined that C-KIT stimulates MAP kinase–interacting serine/threonine kinases 1 and 2 (MNK1/2), which phosphorylate eukaryotic translation initiation factor 4E (eIF4E) and render it oncogenic. Depletion of MNK1/2 in melanoma cells with oncogenic C-KIT inhibited cell migration and mRNA translation of the transcriptional repressor SNAI1 and the cell cycle gene CCNE1. This suggested that blocking MNK1/2 activity may inhibit tumor progression, at least in part, by blocking translation initiation of mRNAs encoding cell migration proteins. Moreover, we developed an MNK1/2 inhibitor (SEL201), and found that SEL201-treated KIT-mutant melanoma cells had lower oncogenicity and reduced metastatic ability. Clinically, tumors from melanoma patients harboring KIT mutations displayed a marked increase in MNK1 and phospho-eIF4E. Thus, our studies indicate that blocking MNK1/2 exerts potent antimelanoma effects and support blocking MNK1/2 as a potential strategy to treat patients positive for KIT mutations. PMID:29035277

MNK1/2 inhibition limits oncogenicity and metastasis of KIT-mutant melanoma.

PubMed

Zhan, Yao; Guo, Jun; Yang, William; Goncalves, Christophe; Rzymski, Tomasz; Dreas, Agnieszka; Żyłkiewicz, Eliza; Mikulski, Maciej; Brzózka, Krzysztof; Golas, Aniela; Kong, Yan; Ma, Meng; Huang, Fan; Huor, Bonnie; Guo, Qianyu; da Silva, Sabrina Daniela; Torres, Jose; Cai, Yutian; Topisirovic, Ivan; Su, Jie; Bijian, Krikor; Alaoui-Jamali, Moulay A; Huang, Sidong; Journe, Fabrice; Ghanem, Ghanem E; Miller, Wilson H; Del Rincón, Sonia V

2017-11-01

Melanoma can be stratified into unique subtypes based on distinct pathologies. The acral/mucosal melanoma subtype is characterized by aberrant and constitutive activation of the proto-oncogene receptor tyrosine kinase C-KIT, which drives tumorigenesis. Treatment of these melanoma patients with C-KIT inhibitors has proven challenging, prompting us to investigate the downstream effectors of the C-KIT receptor. We determined that C-KIT stimulates MAP kinase-interacting serine/threonine kinases 1 and 2 (MNK1/2), which phosphorylate eukaryotic translation initiation factor 4E (eIF4E) and render it oncogenic. Depletion of MNK1/2 in melanoma cells with oncogenic C-KIT inhibited cell migration and mRNA translation of the transcriptional repressor SNAI1 and the cell cycle gene CCNE1. This suggested that blocking MNK1/2 activity may inhibit tumor progression, at least in part, by blocking translation initiation of mRNAs encoding cell migration proteins. Moreover, we developed an MNK1/2 inhibitor (SEL201), and found that SEL201-treated KIT-mutant melanoma cells had lower oncogenicity and reduced metastatic ability. Clinically, tumors from melanoma patients harboring KIT mutations displayed a marked increase in MNK1 and phospho-eIF4E. Thus, our studies indicate that blocking MNK1/2 exerts potent antimelanoma effects and support blocking MNK1/2 as a potential strategy to treat patients positive for KIT mutations.

Dabrafenib in combination with trametinib in the treatment of patients with BRAF V600-positive advanced or metastatic non-small cell lung cancer: clinical evidence and experience.

PubMed

Khunger, Arjun; Khunger, Monica; Velcheti, Vamsidhar

2018-01-01

Mutations in the BRAF oncogene are found in 2-4% of all non-small cell lung cancer (NSCLC) patients. The most common activating mutation present within the BRAF oncogene is associated with valine substitution for glutamate at position 600 (V600E) within the BRAF kinase. BRAF-targeted therapies are effective in patients with melanoma and NSCLC harboring BRAF V600E mutation. In both melanoma and NSCLC, dual inhibition of both BRAF and the downstream mitogen-activated protein kinase (MEK) improves response rates compared with BRAF inhibition alone. BRAF-MEK combination therapy (dabrafenib plus trametinib) demonstrated tolerability and efficacy in a recent phase II clinical trial and was approved by the European Medicines Agency and United States Food and Drug Administration for patients with stage IV NSCLC harboring BRAF V600E mutation. Here, in this review, we outline the preclinical and clinical data for BRAF and MEK inhibitor combination treatment for NSCLC patients with BRAF V600E mutation.

Targeting the RAS oncogene

PubMed Central

Takashima, Asami

2013-01-01

Introduction The Ras proteins (K-Ras, N-Ras, H-Ras) are GTPases that function as molecular switches for a variety of critical cellular activities and their function is tightly and temporally regulated in normal cells. Oncogenic mutations in the RAS genes, which create constitutively-active Ras proteins, can result in uncontrolled proliferation or survival in tumor cells. Areas covered The paper discusses three therapeutic approaches targeting the Ras pathway in cancer: 1) Ras itself, 2) Ras downstream pathways, and 3) synthetic lethality. The most adopted approach is targeting Ras downstream signaling, and specifically the PI3K-AKT-mTOR and Raf-MEK pathways, as they are frequently major oncogenic drivers in cancers with high Ras signaling. Although direct targeting of Ras has not been successful clinically, newer approaches being investigated in preclinical studies, such as RNA interference-based and synthetic lethal approaches, promise great potential for clinical application. Expert opinion The challenges of current and emerging therapeutics include the lack of “tumor specificity” and their limitation to those cancers which are “dependent” upon aberrant Ras signaling for survival. While the newer approaches have the potential to overcome these limitations, they also highlight the importance of robust preclinical studies and bidirectional translational research for successful clinical development of Ras-related targeted therapies. PMID:23360111

PAK1 is a breast cancer oncogene that coordinately activates MAPK and MET signaling

PubMed Central

Shrestha, Yashaswi; Schafer, Eric J.; Boehm, Jesse S.; Thomas, Sapana R.; He, Frank; Du, Jinyan; Wang, Shumei; Barretina, Jordi; Weir, Barbara A.; Zhao, Jean J.; Polyak, Kornelia; Golub, Todd R.; Beroukhim, Rameen; Hahn, William C.

2011-01-01

Activating mutations in the RAS family or BRAF frequently occur in many types of human cancers but are rarely detected in breast tumors. However, activation of the RAS-RAF-MEK-ERK Mitogen-Activated Protein Kinase (MAPK) pathway is commonly observed in human breast cancers, suggesting that other genetic alterations lead to activation of this signaling pathway. To identify breast cancer oncogenes that activate the MAPK pathway, we screened a library of human kinases for their ability to induce anchorage-independent growth in a derivative of immortalized human mammary epithelial cells (HMLE). We identified PAK1 as a kinase that permitted HMLE cells to form anchorage-independent colonies. PAK1 is amplified in several human cancer types, including 33% of breast tumor samples and cancer cell lines. The kinase activity of PAK1 is necessary for PAK1-induced transformation. Moreover, we show that PAK1 simultaneously activates MAPK and MET signaling; the latter via inhibition of Merlin. Disruption of these activities inhibits PAK1-driven anchorage-independent growth. These observations establish PAK1 amplification as an alternative mechanism for MAPK activation in human breast cancer and credential PAK1 as a breast cancer oncogene that coordinately regulates multiple signaling pathways, the cooperation of which leads to malignant transformation. PMID:22105362

PAK1 is a breast cancer oncogene that coordinately activates MAPK and MET signaling.

PubMed

Shrestha, Y; Schafer, E J; Boehm, J S; Thomas, S R; He, F; Du, J; Wang, S; Barretina, J; Weir, B A; Zhao, J J; Polyak, K; Golub, T R; Beroukhim, R; Hahn, W C

2012-07-19

Activating mutations in the RAS family or BRAF frequently occur in many types of human cancers but are rarely detected in breast tumors. However, activation of the RAS-RAF-MEK-ERK MAPK pathway is commonly observed in human breast cancers, suggesting that other genetic alterations lead to activation of this signaling pathway. To identify breast cancer oncogenes that activate the MAPK pathway, we screened a library of human kinases for their ability to induce anchorage-independent growth in a derivative of immortalized human mammary epithelial cells (HMLE). We identified p21-activated kinase 1 (PAK1) as a kinase that permitted HMLE cells to form anchorage-independent colonies. PAK1 is amplified in several human cancer types, including 30--33% of breast tumor samples and cancer cell lines. The kinase activity of PAK1 is necessary for PAK1-induced transformation. Moreover, we show that PAK1 simultaneously activates MAPK and MET signaling; the latter via inhibition of merlin. Disruption of these activities inhibits PAK1-driven anchorage-independent growth. These observations establish PAK1 amplification as an alternative mechanism for MAPK activation in human breast cancer and credential PAK1 as a breast cancer oncogene that coordinately regulates multiple signaling pathways, the cooperation of which leads to malignant transformation.

More antitumor efficacy of the PI3K inhibitor GDC-0941 in breast cancer with PIK3CA mutation or HER2 amplification status in vitro.

PubMed

Zheng, Jie; Wang, Huan; Yao, Jia; Zou, Xianjin

2014-01-01

PIK3CA is probably the most commonly mutated kinase in several malignant tumors. Activation of class I phosphatidylinositol 3' kinase (PI3K) regulates tumor proliferation, survival, etc. This study sought to identify whether the pan-inhibitor has more antitumor efficacy in breast cancer cells with PIK3CA Mutation or HER2 amplification than basal-like cancer cells. The proliferation of breast cancer cells was measured by MTT assay in the presence of GDC-0941. Afterwards, we determined the visible changes in signaling in the PI3K/AKT/mTOR pathway. Finally, we examined GDC-0941 effects on cell cycle, apoptosis and motility. GDC-0941 exhibited excellent inhibition on three cell lines with PIK3CA mutation or HER2 amplification. In addition, GDC-0941 resulted in decreased Akt activity. GDC-0941 downregulated the key components of the cell cycle machinery, such as cyclin D1, upregulated the apoptotic markers and inhibited cell motility on three cell lines with PIK3CA Mutation or HER2 amplification. Antitumor activity of GDC-0941 treatment amongst tumor cell lines with PIK3CA mutation and HER2 amplification may have clinical utility in patients with these oncogenic alterations.

Epidermal Growth Factor Receptor Activation in Glioblastoma through Novel Missense Mutations in the Extracellular Domain

PubMed Central

Lee, Jeffrey C; Vivanco, Igor; Beroukhim, Rameen; Huang, Julie H. Y; Feng, Whei L; DeBiasi, Ralph M; Yoshimoto, Koji; King, Jennifer C; Nghiemphu, Phioanh; Yuza, Yuki; Xu, Qing; Greulich, Heidi; Thomas, Roman K; Paez, J. Guillermo; Peck, Timothy C; Linhart, David J; Glatt, Karen A; Getz, Gad; Onofrio, Robert; Ziaugra, Liuda; Levine, Ross L; Gabriel, Stacey; Kawaguchi, Tomohiro; O'Neill, Keith; Khan, Haumith; Liau, Linda M; Nelson, Stanley F; Rao, P. Nagesh; Mischel, Paul; Pieper, Russell O; Cloughesy, Tim; Leahy, Daniel J; Sellers, William R; Sawyers, Charles L; Meyerson, Matthew; Mellinghoff, Ingo K

2006-01-01

Background Protein tyrosine kinases are important regulators of cellular homeostasis with tightly controlled catalytic activity. Mutations in kinase-encoding genes can relieve the autoinhibitory constraints on kinase activity, can promote malignant transformation, and appear to be a major determinant of response to kinase inhibitor therapy. Missense mutations in the EGFR kinase domain, for example, have recently been identified in patients who showed clinical responses to EGFR kinase inhibitor therapy. Methods and Findings Encouraged by the promising clinical activity of epidermal growth factor receptor (EGFR) kinase inhibitors in treating glioblastoma in humans, we have sequenced the complete EGFR coding sequence in glioma tumor samples and cell lines. We identified novel missense mutations in the extracellular domain of EGFR in 13.6% (18/132) of glioblastomas and 12.5% (1/8) of glioblastoma cell lines. These EGFR mutations were associated with increased EGFR gene dosage and conferred anchorage-independent growth and tumorigenicity to NIH-3T3 cells. Cells transformed by expression of these EGFR mutants were sensitive to small-molecule EGFR kinase inhibitors. Conclusions Our results suggest extracellular missense mutations as a novel mechanism for oncogenic EGFR activation and may help identify patients who can benefit from EGFR kinase inhibitors for treatment of glioblastoma. PMID:17177598

Epigenetics and colorectal cancer pathogenesis.

PubMed

Bardhan, Kankana; Liu, Kebin

2013-06-05

Colorectal cancer (CRC) develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy.

Epigenetics and Colorectal Cancer Pathogenesis

PubMed Central

Bardhan, Kankana; Liu, Kebin

2013-01-01

Colorectal cancer (CRC) develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy. PMID:24216997

SUMOylated MAFB promotes colorectal cancer tumorigenesis

PubMed Central

Xie, Yin-Yin; Sun, Xiao-Jian; Zhao, Ren; Huang, Qiu-Hua

2016-01-01

The transcription factor, v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog B (MAFB), promotes tumorigenesis in some cancers. In this study, we found that MAFB levels were increased in clinical colorectal cancer (CRC) samples, and higher expression correlated with more advanced TNM stage. We identified MAFB amplifications in a majority of tumor types in an assessment of The Cancer Genome Atlas database. Altered MAFB levels due to gene amplification, deletion, mutation, or transcription upregulation occurred in 9% of CRC cases within the database. shRNA knockdown experiments demonstrated that MAFB deficiency blocked CRC cell proliferation by arresting the cell cycle at G0/G1 phase in vitro. We found that MAFB could be SUMOylated by SUMO1 at lysine 32, and this modification was critical for cell cycle regulation by MAFB in CRC cells. SUMOylated MAFB directly regulated cyclin-dependent kinase 6 transcription by binding to its promoter. MAFB knockdown CRC cell xenograft tumors in mice grew more slowly than controls, and wild-type MAFB-overexpressing tumors grew more quickly than tumors overexpressing MAFB mutated at lysine 32. These data suggest that SUMOylated MAFB promotes CRC tumorigenesis through cell cycle regulation. MAFB and its SUMOylation process may serve as novel therapeutic targets for CRC treatment. PMID:27829226

CRISPR-Barcoding for Intratumor Genetic Heterogeneity Modeling and Functional Analysis of Oncogenic Driver Mutations.

PubMed

Guernet, Alexis; Mungamuri, Sathish Kumar; Cartier, Dorthe; Sachidanandam, Ravi; Jayaprakash, Anitha; Adriouch, Sahil; Vezain, Myriam; Charbonnier, Françoise; Rohkin, Guy; Coutant, Sophie; Yao, Shen; Ainani, Hassan; Alexandre, David; Tournier, Isabelle; Boyer, Olivier; Aaronson, Stuart A; Anouar, Youssef; Grumolato, Luca

2016-08-04

Intratumor genetic heterogeneity underlies the ability of tumors to evolve and adapt to different environmental conditions. Using CRISPR/Cas9 technology and specific DNA barcodes, we devised a strategy to recapitulate and trace the emergence of subpopulations of cancer cells containing a mutation of interest. We used this approach to model different mechanisms of lung cancer cell resistance to EGFR inhibitors and to assess effects of combined drug therapies. By overcoming intrinsic limitations of current approaches, CRISPR-barcoding also enables investigation of most types of genetic modifications, including repair of oncogenic driver mutations. Finally, we used highly complex barcodes inserted at a specific genome location as a means of simultaneously tracing the fates of many thousands of genetically labeled cancer cells. CRISPR-barcoding is a straightforward and highly flexible method that should greatly facilitate the functional investigation of specific mutations, in a context that closely mimics the complexity of cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Mediator kinase module and human tumorigenesis.

PubMed

Clark, Alison D; Oldenbroek, Marieke; Boyer, Thomas G

2015-01-01

Mediator is a conserved multi-subunit signal processor through which regulatory informatiosn conveyed by gene-specific transcription factors is transduced to RNA Polymerase II (Pol II). In humans, MED13, MED12, CDK8 and Cyclin C (CycC) comprise a four-subunit "kinase" module that exists in variable association with a 26-subunit Mediator core. Genetic and biochemical studies have established the Mediator kinase module as a major ingress of developmental and oncogenic signaling through Mediator, and much of its function in signal-dependent gene regulation derives from its resident CDK8 kinase activity. For example, CDK8-targeted substrate phosphorylation impacts transcription factor half-life, Pol II activity and chromatin chemistry and functional status. Recent structural and biochemical studies have revealed a precise network of physical and functional subunit interactions required for proper kinase module activity. Accordingly, pathologic change in this activity through altered expression or mutation of constituent kinase module subunits can have profound consequences for altered signaling and tumor formation. Herein, we review the structural organization, biological function and oncogenic potential of the Mediator kinase module. We focus principally on tumor-associated alterations in kinase module subunits for which mechanistic relationships as opposed to strictly correlative associations are established. These considerations point to an emerging picture of the Mediator kinase module as an oncogenic unit, one in which pathogenic activation/deactivation through component change drives tumor formation through perturbation of signal-dependent gene regulation. It follows that therapeutic strategies to combat CDK8-driven tumors will involve targeted modulation of CDK8 activity or pharmacologic manipulation of dysregulated CDK8-dependent signaling pathways.

Mediator kinase module and human tumorigenesis

PubMed Central

Clark, Alison D.; Oldenbroek, Marieke; Boyer, Thomas G.

2016-01-01

Mediator is a conserved multi-subunit signal processor through which regulatory informatiosn conveyed by gene-specific transcription factors is transduced to RNA Polymerase II (Pol II). In humans, MED13, MED12, CDK8 and Cyclin C (CycC) comprise a four-subunit “kinase” module that exists in variable association with a 26-subunit Mediator core. Genetic and biochemical studies have established the Mediator kinase module as a major ingress of developmental and oncogenic signaling through Mediator, and much of its function in signal-dependent gene regulation derives from its resident CDK8 kinase activity. For example, CDK8-targeted substrate phosphorylation impacts transcription factor half-life, Pol II activity and chromatin chemistry and functional status. Recent structural and biochemical studies have revealed a precise network of physical and functional subunit interactions required for proper kinase module activity. Accordingly, pathologic change in this activity through altered expression or mutation of constituent kinase module subunits can have profound consequences for altered signaling and tumor formation. Herein, we review the structural organization, biological function and oncogenic potential of the Mediator kinase module. We focus principally on tumor-associated alterations in kinase module subunits for which mechanistic relationships as opposed to strictly correlative associations are established. These considerations point to an emerging picture of the Mediator kinase module as an oncogenic unit, one in which pathogenic activation/deactivation through component change drives tumor formation through perturbation of signal-dependent gene regulation. It follows that therapeutic strategies to combat CDK8-driven tumors will involve targeted modulation of CDK8 activity or pharmacologic manipulation of dysregulated CDK8-dependent signaling pathways. PMID:26182352

Contributions of intrinsic mutation rate and selfish selection to levels of de novo HRAS mutations in the paternal germline

PubMed Central

Giannoulatou, Eleni; McVean, Gilean; Taylor, Indira B.; McGowan, Simon J.; Maher, Geoffrey J.; Iqbal, Zamin; Pfeifer, Susanne P.; Turner, Isaac; Burkitt Wright, Emma M. M.; Shorto, Jennifer; Itani, Aysha; Turner, Karen; Gregory, Lorna; Buck, David; Rajpert-De Meyts, Ewa; Looijenga, Leendert H. J.; Kerr, Bronwyn; Wilkie, Andrew O. M.; Goriely, Anne

2013-01-01

The RAS proto-oncogene Harvey rat sarcoma viral oncogene homolog (HRAS) encodes a small GTPase that transduces signals from cell surface receptors to intracellular effectors to control cellular behavior. Although somatic HRAS mutations have been described in many cancers, germline mutations cause Costello syndrome (CS), a congenital disorder associated with predisposition to malignancy. Based on the epidemiology of CS and the occurrence of HRAS mutations in spermatocytic seminoma, we proposed that activating HRAS mutations become enriched in sperm through a process akin to tumorigenesis, termed selfish spermatogonial selection. To test this hypothesis, we quantified the levels, in blood and sperm samples, of HRAS mutations at the p.G12 codon and compared the results to changes at the p.A11 codon, at which activating mutations do not occur. The data strongly support the role of selection in determining HRAS mutation levels in sperm, and hence the occurrence of CS, but we also found differences from the mutation pattern in tumorigenesis. First, the relative prevalence of mutations in sperm correlates weakly with their in vitro activating properties and occurrence in cancers. Second, specific tandem base substitutions (predominantly GC>TT/AA) occur in sperm but not in cancers; genomewide analysis showed that this same mutation is also overrepresented in constitutional pathogenic and polymorphic variants, suggesting a heightened vulnerability to these mutations in the germline. We developed a statistical model to show how both intrinsic mutation rate and selfish selection contribute to the mutational burden borne by the paternal germline. PMID:24259709

Contributions of intrinsic mutation rate and selfish selection to levels of de novo HRAS mutations in the paternal germline.

PubMed

Giannoulatou, Eleni; McVean, Gilean; Taylor, Indira B; McGowan, Simon J; Maher, Geoffrey J; Iqbal, Zamin; Pfeifer, Susanne P; Turner, Isaac; Burkitt Wright, Emma M M; Shorto, Jennifer; Itani, Aysha; Turner, Karen; Gregory, Lorna; Buck, David; Rajpert-De Meyts, Ewa; Looijenga, Leendert H J; Kerr, Bronwyn; Wilkie, Andrew O M; Goriely, Anne

2013-12-10

The RAS proto-oncogene Harvey rat sarcoma viral oncogene homolog (HRAS) encodes a small GTPase that transduces signals from cell surface receptors to intracellular effectors to control cellular behavior. Although somatic HRAS mutations have been described in many cancers, germline mutations cause Costello syndrome (CS), a congenital disorder associated with predisposition to malignancy. Based on the epidemiology of CS and the occurrence of HRAS mutations in spermatocytic seminoma, we proposed that activating HRAS mutations become enriched in sperm through a process akin to tumorigenesis, termed selfish spermatogonial selection. To test this hypothesis, we quantified the levels, in blood and sperm samples, of HRAS mutations at the p.G12 codon and compared the results to changes at the p.A11 codon, at which activating mutations do not occur. The data strongly support the role of selection in determining HRAS mutation levels in sperm, and hence the occurrence of CS, but we also found differences from the mutation pattern in tumorigenesis. First, the relative prevalence of mutations in sperm correlates weakly with their in vitro activating properties and occurrence in cancers. Second, specific tandem base substitutions (predominantly GC>TT/AA) occur in sperm but not in cancers; genomewide analysis showed that this same mutation is also overrepresented in constitutional pathogenic and polymorphic variants, suggesting a heightened vulnerability to these mutations in the germline. We developed a statistical model to show how both intrinsic mutation rate and selfish selection contribute to the mutational burden borne by the paternal germline.

Nonoverlapping Clinical and Mutational Patterns in Melanomas from the Female Genital Tract and Atypical Genital Nevi.

PubMed

Yélamos, Oriol; Merkel, Emily A; Sholl, Lauren Meldi; Zhang, Bin; Amin, Sapna M; Lee, Christina Y; Guitart, Gerta E; Yang, Jingyi; Wenzel, Alexander T; Bunick, Christopher G; Yazdan, Pedram; Choi, Jaehyuk; Gerami, Pedram

2016-09-01

Genital melanomas (GM) are the second most common cancer of the female external genitalia and may be confused with atypical genital nevi (AGN), which exhibit atypical histological features but have benign behavior. In this study, we compared the clinical, histological, and molecular features of 19 GM and 25 AGN. We described chromosomal copy number aberrations and the mutational status of 50 oncogenes and tumor suppressor genes in both groups. Our study showed that a pigmented lesion occurring in mucosal tissue, particularly in postmenopausal women, was more likely to be a melanoma than a nevus. GM had high levels of chromosomal instability, with many copy number aberrations. Furthermore, we found a completely nonoverlapping pattern of oncogenic mutations when comparing GM and AGN. In GM, we report somatic mutations in KIT and TP53. Conversely, AGN had frequent BRAF V600E mutations, which were not seen in any of the GM. Our results show that GM and AGN have distinct clinical and molecular changes and that GM have a different mutational pattern compared with AGN. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Liquid Biopsies in the Screening of Oncogenic Mutations in NSCLC and its Application in Targeted Therapy.

PubMed

Tang, Jason H; Chia, David

2015-01-01

Non-small cell lung cancer (NSCLC) still dominates cancer-related deaths in America. Despite this, new discoveries and advancements in technology are helping with the detection and treatment of NSCLC. The discovery of circulating tumor DNA in blood and other biofluids is essential for the creation of a DNA biomarker. Limitations in technology and sequencing have stunted assay development, but with recent advancements in the next-generation sequencing, droplet digital PCR, and EFIRM, the detection of mutations in biofluids has become possible with reasonable sensitivity and specificity. These methods have been applied to the detection of mutations in NSCLC by measuring the levels of circulating tumor DNA. ALK fusion genes along with mutations in EGFR and KRAS have been shown to correlate to tumor size and metastasis. These methods allow for noninvasive, affordable, and efficient diagnoses of oncogenic mutations that overcome the issues of traditional biopsies. These issues include tumor heterogeneity and early detection of cancers with asymptomatic early stages. Early detection and treatment remain the best way to ensure survival. This review aims to describe these new technologies along with their application in mutation detection in NSCLC in order to proactively utilize targeted anticancer therapy.

Next generation sequencing of Cytokeratin 20-negative Merkel cell carcinoma reveals ultraviolet-signature mutations and recurrent TP53 and RB1 inactivation.

PubMed

Harms, Paul W; Collie, Angela M B; Hovelson, Daniel H; Cani, Andi K; Verhaegen, Monique E; Patel, Rajiv M; Fullen, Douglas R; Omata, Kei; Dlugosz, Andrzej A; Tomlins, Scott A; Billings, Steven D

2016-03-01

Merkel cell carcinoma is a rare but highly aggressive cutaneous neuroendocrine carcinoma. Cytokeratin 20 (CK20) is expressed in ~95% of Merkel cell carcinomas and is useful for distinction from morphologically similar entities including metastatic small-cell lung carcinoma. Lack of CK20 expression may make diagnosis of Merkel cell carcinoma more challenging, and has unknown biological significance. Approximately 80% of CK20-positive Merkel cell carcinomas are associated with the oncogenic Merkel cell polyomavirus. Merkel cell carcinomas lacking Merkel cell polyomavirus display distinct genetic changes from Merkel cell polyomavirus-positive Merkel cell carcinoma, including RB1 inactivating mutations. Unlike CK20-positive Merkel cell carcinoma, the majority of CK20-negative Merkel cell carcinomas are Merkel cell polyomavirus-negative, suggesting CK20-negative Merkel cell carcinomas predominantly arise through virus-independent pathway(s) and may harbor additional genetic differences from conventional Merkel cell carcinoma. Hence, we analyzed 15 CK20-negative Merkel cell carcinoma tumors (10 Merkel cell polyomavirus-negative, four Merkel cell polyomavirus-positive, and one undetermined) using the Ion Ampliseq Comprehensive Cancer Panel, which assesses copy number alterations and mutations in 409 cancer-relevant genes. Twelve tumors displayed prioritized high-level chromosomal gains or losses (average 1.9 per tumor). Non-synonymous high-confidence somatic mutations were detected in 14 tumors (average 11.9 per tumor). Assessing all somatic coding mutations, an ultraviolet-signature mutational profile was present, and more prevalent in Merkel cell polyomavirus-negative tumors. Recurrent deleterious tumor suppressor mutations affected TP53 (9/15, 60%), RB1 (3/15, 20%), and BAP1 (2/15, 13%). Oncogenic activating mutations included PIK3CA (3/15, 20%), AKT1 (1/15, 7%) and EZH2 (1/15, 7%). In conclusion, CK20-negative Merkel cell carcinoma display overlapping genetic changes with CK20-positive Merkel cell carcinoma, including RB1 mutations restricted to Merkel cell polyomavirus-negative tumors. However, some CK20-negative Merkel cell carcinomas harbor mutations not previously described in Merkel cell carcinoma. Hence, CK20-negative Merkel cell carcinomas harbor diverse oncogenic drivers which may represent therapeutic targets in individual tumors.

Next Generation Sequencing of Cytokeratin 20-Negative Merkel Cell Carcinoma Reveals Ultraviolet Signature Mutations and Recurrent TP53 and RB1 Inactivation

PubMed Central

Harms, Paul W.; Collie, Angela M. B.; Hovelson, Daniel H.; Cani, Andi K.; Verhaegen, Monique E.; Patel, Rajiv M.; Fullen, Douglas R.; Omata, Kei; Dlugosz, Andrzej A.; Tomlins, Scott A.; Billings, Steven D.

2016-01-01

Merkel cell carcinoma is a rare but highly aggressive cutaneous neuroendocrine carcinoma. Cytokeratin-20 (CK20) is expressed in approximately 95% of Merkel cell carcinomas and is useful for distinction from morphologically similar entities including metastatic small cell lung carcinoma. Lack of CK20 expression may make diagnosis of Merkel cell carcinoma more challenging, and has unknown biological significance. Approximately 80% of CK20-positive Merkel cell carcinomas are associated with the oncogenic Merkel cell polyomavirus. Merkel cell carcinomas lacking Merkel cell polyomavirus display distinct genetic changes from Merkel cell polyomavirus-positive Merkel cell carcinoma, including RB1 inactivating mutations. Unlike CK20-positive Merkel cell carcinoma, the majority of CK20-negative Merkel cell carcinomas are Merkel cell polyomavirus-negative, suggesting CK20-negative Merkel cell carcinomas predominantly arise through virus-independent pathway(s) and may harbor additional genetic differences from conventional Merkel cell carcinoma. Hence, we analyzed 15 CK20-negative Merkel cell carcinoma tumors (ten Merkel cell polyomavirus-negative, four Merkel cell polyomavirus-positive, and one undetermined) using the Ion Ampliseq Comprehensive Cancer Panel, which assesses copy number alterations and mutations in 409 cancer-relevant genes. Twelve tumors displayed prioritized high-level chromosomal gains or losses (average 1.9 per tumor). Non-synonymous high confidence somatic mutations were detected in 14 tumors (average 11.9 per tumor). Assessing all somatic coding mutations, an ultraviolet-signature mutational profile was present, and more prevalent in Merkel cell polyomavirus-negative tumors. Recurrent deleterious tumor suppressor mutations affected TP53 (9/15, 60%), RB1 (3/15, 20%), and BAP1 (2/15, 13%). Oncogenic activating mutations included PIK3CA (3/15, 20%), AKT1 (1/15, 7%)) and EZH2 (1/15, 7%). In conclusion, CK20-negative Merkel cell carcinoma display overlapping genetic changes with CK20-positive Merkel cell carcinoma, including RB1 mutations restricted to Merkel cell polyomavirus-negative tumors. However, some CK20-negative Merkel cell carcinomas harbor mutations not previously described in Merkel cell carcinoma. Hence, CK20-negative Merkel cell carcinomas harbor diverse oncogenic drivers which may represent therapeutic targets in individual tumors. PMID:26743471

Targeted sequencing identifies associations between IL7R-JAK mutations and epigenetic modulators in T-cell acute lymphoblastic leukemia

PubMed Central

Vicente, Carmen; Schwab, Claire; Broux, Michaël; Geerdens, Ellen; Degryse, Sandrine; Demeyer, Sofie; Lahortiga, Idoya; Elliott, Alannah; Chilton, Lucy; La Starza, Roberta; Mecucci, Cristina; Vandenberghe, Peter; Goulden, Nicholas; Vora, Ajay; Moorman, Anthony V.; Soulier, Jean; Harrison, Christine J.; Clappier, Emmanuelle; Cools, Jan

2015-01-01

T-cell acute lymphoblastic leukemia is caused by the accumulation of multiple oncogenic lesions, including chromosomal rearrangements and mutations. To determine the frequency and co-occurrence of mutations in T-cell acute lymphoblastic leukemia, we performed targeted re-sequencing of 115 genes across 155 diagnostic samples (44 adult and 111 childhood cases). NOTCH1 and CDKN2A/B were mutated/deleted in more than half of the cases, while an additional 37 genes were mutated/deleted in 4% to 20% of cases. We found that IL7R-JAK pathway genes were mutated in 27.7% of cases, with JAK3 mutations being the most frequent event in this group. Copy number variations were also detected, including deletions of CREBBP or CTCF and duplication of MYB. FLT3 mutations were rare, but a novel extracellular mutation in FLT3 was detected and confirmed to be transforming. Furthermore, we identified complex patterns of pairwise associations, including a significant association between mutations in IL7R-JAK genes and epigenetic regulators (WT1, PRC2, PHF6). Our analyses showed that IL7R-JAK genetic lesions did not confer adverse prognosis in T-cell acute lymphoblastic leukemia cases enrolled in the UK ALL2003 trial. Overall, these results identify interconnections between the T-cell acute lymphoblastic leukemia genome and disease biology, and suggest a potential clinical application for JAK inhibitors in a significant proportion of patients with T-cell acute lymphoblastic leukemia. PMID:26206799

Oncogenic Activation of Fibroblast Growth Factor Receptor-3 and RAS Genes as Non-Overlapping Mutual Exclusive Events in Urinary Bladder Cancer.

PubMed

Pandith, Arshad A; Hussain, Aashaq; Khan, Mosin S; Shah, Zafar A; Wani, M Saleem; Siddiqi, Mushtaq A

2016-01-01

Urinary bladder cancer is a common malignancy in the West and ranks as the 7th most common cancer in our region of Kashmir, India. FGFR3 mutations are frequent in superficial urothelial carcinoma (UC) differing from the RAS gene mutational pattern. The aim of this study was to analyze the frequency and association of FGFR3 and RAS gene mutations in UC cases. Paired tumor and adjacent normal tissue specimens of 65 consecutive UC patients were examined. DNA preparations were evaluated for the occurrence of FGFR3 and RAS gene mutations by PCR-SCCP and DNA sequencing. Somatic point mutations of FGFR3 were identified in 32.3% (21 of 65). The pattern and distribution were significantly associated with low grade/stage (<0.05). The overall mutations in exon 1 and 2 in all the forms of RAS genes aggregated to 21.5% and showed no association with any clinic-pathological parameters. In total, 53.8% (35 of 65) of the tumors studied had mutations in either a RAS or FGFR3 gene, but these were totally mutually exclusive in and none of the samples showed both the mutational events in mutually exclusive RAS and FGFR3. We conclude that RAS and FGFR3 mutations in UC are mutually exclusive and non-overlapping events which reflect activation of oncogenic pathways through different elements.

Association between mutations of critical pathway genes and survival outcomes according to the tumor location in colorectal cancer.

PubMed

Lee, Dae-Won; Han, Sae-Won; Cha, Yongjun; Bae, Jeong Mo; Kim, Hwang-Phill; Lyu, Jaemyun; Han, Hyojun; Kim, Hyoki; Jang, Hoon; Bang, Duhee; Huh, Iksoo; Park, Taesung; Won, Jae-Kyung; Jeong, Seung-Yong; Park, Kyu Joo; Kang, Gyeong Hoon; Kim, Tae-You

2017-09-15

Colorectal cancer (CRC) develops through the alteration of several critical pathways. This study was aimed at evaluating the influence of critical pathways on survival outcomes for patients with CRC. Targeted next-generation sequencing of 40 genes included in the 5 critical pathways of CRC (WNT, P53, RTK-RAS, phosphatidylinositol-4,5-bisphosphate 3-kinase [PI3K], and transforming growth factor β [TGF-β]) was performed for 516 patients with stage III or high-risk stage II CRC treated with surgery followed by adjuvant fluoropyrimidine and oxaliplatin chemotherapy. The associations between critical pathway mutations and relapse-free survival (RFS) and overall survival were analyzed. The associations were further analyzed according to the tumor location. The mutation rates for the WNT, P53, RTK-RAS, PI3K, and TGF-β pathways were 84.5%, 69.0%, 60.7%, 30.0%, and 28.9%, respectively. A mutation in the PI3K pathway was associated with longer RFS (adjusted hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.36-0.99), whereas a mutation in the RTK-RAS pathway was associated with shorter RFS (adjusted HR, 1.60; 95% CI, 1.01-2.52). Proximal tumors showed a higher mutation rate than distal tumors, and the mutation profile was different according to the tumor location. The mutation rates of Kirsten rat sarcoma viral oncogene homolog (KRAS), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA), and B-Raf proto-oncogene serine/threonine kinase (BRAF) were higher in proximal tumors, and the mutation rates of adenomatous polyposis coli (APC), tumor protein 53 (TP53), and neuroblastoma RAS viral oncogene homolog (NRAS) were higher in distal tumors. The better RFS with the PI3K pathway mutation was significant only for proximal tumors, and the worse RFS with the RTK-RAS pathway mutation was significant only for distal tumors. A PI3K pathway mutation was associated with better RFS for CRC patients treated with adjuvant chemotherapy, and an RTK-RAS pathway mutation was associated with worse RFS. The significance of the prognostic impact differed according to the tumor location. Cancer 2017;123:3513-23. © 2017 American Cancer Society. © 2017 American Cancer Society.

CBL enhances breast tumor formation by inhibiting tumor suppressive activity of TGF-β signaling.

PubMed

Kang, J M; Park, S; Kim, S J; Hong, H Y; Jeong, J; Kim, H-S; Kim, S-J

2012-12-13

Casitas B-lineage lymphoma (CBL) protein family functions as multifunctional adaptor proteins and E3 ubiquitin ligases that are implicated as regulators of signaling in various cell types. Recent discovery revealed mutations of proto-oncogenic CBL in the linker region and RING finger domain in human acute myeloid neoplasm, and these transforming mutations induced carcinogenesis. However, the adaptor function of CBL mediated signaling pathway during tumorigenesis has not been well characterized. Here, we show that CBL is highly expressed in breast cancer cells and significantly inhibits transforming growth factor-β (TGF-β) tumor suppressive activity. Knockdown of CBL expression resulted in the increased expression of TGF-β target genes, PAI-I and CDK inhibitors such as p15(INK4b) and p21(Cip1). Furthermore, we demonstrate that CBL is frequently overexpressed in human breast cancer tissues, and the loss of CBL decreases the tumorigenic activity of breast cancer cells in vivo. CBL directly binds to Smad3 through its proline-rich motif, thereby preventing Smad3 from interacting with Smad4 and blocking nuclear translocation of Smad3. CBL-b, one of CBL protein family, also interacted with Smad3 and knockdown of both CBL and CBL-b further enhanced TGF-β transcriptional activity. Our findings provide evidence for a previously undescribed mechanism by which oncogenic CBL can block TGF-β tumor suppressor activity.

Crosstalk of the EphA2 Receptor with a Serine/Threonine Phosphatase Suppresses the Akt-mTORC1 Pathway in Cancer Cells

PubMed Central

Yang, Nai-Ying; Fernandez, Carlos; Richter, Melanie; Xiao, Zhan; Valencia, Fatima; Tice, David A.; Pasquale, Elena B.

2010-01-01

Receptor tyrosine kinases of the Eph family play multiple roles in the physiological regulation of tissue homeostasis and in the pathogenesis of various diseases, including cancer. The EphA2 receptor is highly expressed in most cancer cell types, where it has disparate activities that are not well understood. It has been reported that interplay of EphA2 with oncogenic signaling pathways promotes cancer cell malignancy independently of ephrin ligand binding and receptor kinase activity. In contrast, stimulation of EphA2 signaling with ephrin-A ligands can suppress malignancy by inhibiting the Ras-MAP kinase pathway, integrin-mediated adhesion, and epithelial to mesenchymal transition. Here we show that ephrin-A1 ligand-dependent activation of EphA2 decreases the growth of PC3 prostate cancer cells and profoundly inhibits the Akt-mTORC1 pathway, which is hyperactivated due to loss of the PTEN tumor suppressor. Our results do not implicate changes in the activity of Akt upstream regulators (such as Ras family GTPases, PI3 kinase, integrins, or the Ship2 lipid phosphatase) in the observed loss of Akt T308 and S473 phosphorylation downstream of EphA2. Indeed, EphA2 can inhibit Akt phosphorylation induced by oncogenic mutations of not only PTEN but also PI3 kinase. Furthermore, it can decrease the hyperphosphorylation induced by constitutive membrane-targeting of Akt. Our data suggest a novel signaling mechanism whereby EphA2 inactivates the Akt-mTORC1 oncogenic pathway through Akt dephosphorylation mediated by a serine/threonine phosphatase. Ephrin-A1-induced Akt dephosphorylation was observed not only in PC3 prostate cancer cells but also in other cancer cell types. Thus, activation of EphA2 signaling represents a possible new avenue for anti-cancer therapies that exploit the remarkable ability of this receptor to counteract multiple oncogenic signaling pathways. PMID:20837138

Pancreatic Cancer, A Mis-interpreter of the Epigenetic Language.

PubMed

Iguchi, Eriko; Safgren, Stephanie L; Marks, David L; Olson, Rachel L; Fernandez-Zapico, Martin E

2016-12-01

Pancreatic cancer is the third leading cause of cancer mortality in the U.S. with close to 40,000 deaths per year. Pancreatic ductal adenocarcinoma (PDAC) represents approximately 90 percent of all pancreatic cancer cases and is the most lethal form of the disease. Current therapies for PDAC are ineffective and most patients cannot be treated by surgical resection. Most research efforts have primarily focused on how genetic alterations cause, alter progression, contribute to diagnosis, and influence PDAC management. Over the past two decades, a model has been advanced of PDAC initiation and progression as a multi-step process driven by the acquisition of mutations leading to loss of tumor suppressors and activation of oncogenes. The recognition of the essential roles of these genetic alterations in the development of PDAC has revolutionized our knowledge of this disease. However, none of these findings have turned into effective treatment for this dismal malignancy. In recent years, studies in the areas of chromatin modifications, and non-coding RNAs have uncovered mechanisms for regulating gene expression which occur independently of genetic alterations. Chromatin-based mechanisms are interwoven with microRNA-driven regulation of protein translation to create an integrated epigenetic language, which is grossly dysregulated in PDAC. Thus in PDAC, key tumor suppressors that are well established to play a role in PDAC may be repressed, and oncogenes can be upregulated secondary to epigenetic alterations. Unlike mutations, epigenetic changes are potentially reversible. Given this feature of epigenetic mechanisms, it is conceivable that targeting epigenetic-based events promoting and maintaining PDAC could serve as foundation for the development of new therapeutic and diagnostic approaches for this disease.

Loss of Dependence on Continued Expression of the Human Papillomavirus 16 E7 Oncogene in Cervical Cancers and Precancerous Lesions Arising in Fanconi Anemia Pathway-Deficient Mice

PubMed Central

Park, Soyeong; Park, Jung Wook; Pitot, Henry C.

2016-01-01

ABSTRACT   Fanconi anemia (FA) is a rare genetic disorder caused by defects in DNA damage repair. FA patients often develop squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) are known to cause cancer, including the cervix. However, SCCs found in human FA patients are often HPV negative, even though the majority of female FA patients with anogenital cancers had preexisting HPV-positive dysplasia. We hypothesize that HPVs contribute to the development of SCCs in FA patients but that the continued expression of HPV oncogenes is not required for the maintenance of the cancer state because FA deficiency leads to an accumulation of mutations in cellular genes that render the cancer no longer dependent upon viral oncogenes. We tested this hypothesis, making use of Bi-L E7 transgenic mice in which we temporally controlled expression of HPV16 E7, the dominant viral oncogene in HPV-associated cancers. As seen before, the persistence of cervical neoplastic disease was highly dependent upon the continued expression of HPV16 E7 in FA-sufficient mice. However, in mice with FA deficiency, cervical cancers persisted in a large fraction of the mice after HPV16 E7 expression was turned off, indicating that these cancers had escaped from their dependency on E7. Furthermore, the severity of precancerous lesions also failed to be reduced significantly in the mice with FA deficiency upon turning off expression of E7. These findings confirm our hypothesis and may explain the fact that, while FA patients have a high frequency of infections by HPVs and HPV-induced precancerous lesions, the cancers are frequently HPV negative. Importance   Fanconi anemia (FA) patients are at high risk for developing squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) frequently cause cancer. Yet these SCCs are often HPV negative. FA patients have a genetic defect in their capacity to repair damaged DNA. HPV oncogenes cause an accumulation of DNA damage. We hypothesize, therefore, that DNA damage induced by HPV leads to an accumulation of mutations in patients with FA deficiency and that such mutations allow HPV-driven cancers to become independent of the viral oncogenes. Consistent with this hypothesis, we found that cervical cancers arising in HPV16 transgenic mice with FA deficiency frequently escape from dependency on the HPV16 oncogene that drove its development. Our report provides further support for vaccination of FA patients against HPVs and argues for the need to define mutational profiles of SCCs arising in FA patients in order to inform precision medicine-based approaches to treating these patients. PMID:27190216

Loss of Dependence on Continued Expression of the Human Papillomavirus 16 E7 Oncogene in Cervical Cancers and Precancerous Lesions Arising in Fanconi Anemia Pathway-Deficient Mice.

PubMed

Park, Soyeong; Park, Jung Wook; Pitot, Henry C; Lambert, Paul F

2016-05-17

Fanconi anemia (FA) is a rare genetic disorder caused by defects in DNA damage repair. FA patients often develop squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) are known to cause cancer, including the cervix. However, SCCs found in human FA patients are often HPV negative, even though the majority of female FA patients with anogenital cancers had preexisting HPV-positive dysplasia. We hypothesize that HPVs contribute to the development of SCCs in FA patients but that the continued expression of HPV oncogenes is not required for the maintenance of the cancer state because FA deficiency leads to an accumulation of mutations in cellular genes that render the cancer no longer dependent upon viral oncogenes. We tested this hypothesis, making use of Bi-L E7 transgenic mice in which we temporally controlled expression of HPV16 E7, the dominant viral oncogene in HPV-associated cancers. As seen before, the persistence of cervical neoplastic disease was highly dependent upon the continued expression of HPV16 E7 in FA-sufficient mice. However, in mice with FA deficiency, cervical cancers persisted in a large fraction of the mice after HPV16 E7 expression was turned off, indicating that these cancers had escaped from their dependency on E7. Furthermore, the severity of precancerous lesions also failed to be reduced significantly in the mice with FA deficiency upon turning off expression of E7. These findings confirm our hypothesis and may explain the fact that, while FA patients have a high frequency of infections by HPVs and HPV-induced precancerous lesions, the cancers are frequently HPV negative. IMPORTANCE  : Fanconi anemia (FA) patients are at high risk for developing squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) frequently cause cancer. Yet these SCCs are often HPV negative. FA patients have a genetic defect in their capacity to repair damaged DNA. HPV oncogenes cause an accumulation of DNA damage. We hypothesize, therefore, that DNA damage induced by HPV leads to an accumulation of mutations in patients with FA deficiency and that such mutations allow HPV-driven cancers to become independent of the viral oncogenes. Consistent with this hypothesis, we found that cervical cancers arising in HPV16 transgenic mice with FA deficiency frequently escape from dependency on the HPV16 oncogene that drove its development. Our report provides further support for vaccination of FA patients against HPVs and argues for the need to define mutational profiles of SCCs arising in FA patients in order to inform precision medicine-based approaches to treating these patients. Copyright © 2016 Park et al.

Oncogenic Kit signals on endolysosomes and endoplasmic reticulum are essential for neoplastic mast cell proliferation

PubMed Central

Obata, Yuuki; Toyoshima, Shota; Wakamatsu, Ei; Suzuki, Shunichi; Ogawa, Shuhei; Esumi, Hiroyasu; Abe, Ryo

2014-01-01

Kit is a receptor-type tyrosine kinase found on the plasma membrane. It can transform mast cells through activating mutations. Here, we show that a mutant Kit from neoplastic mast cells from mice, Kit(D814Y), is permanently active and allows cells to proliferate autonomously. It does so by activating two signalling pathways from different intracellular compartments. Mutant Kit from the cell surface accumulates on endolysosomes through clathrin-mediated endocytosis, which requires Kit’s kinase activity. Kit(D814Y) is constitutively associated with phosphatidylinositol 3-kinase, but the complex activates Akt only on the cytoplasmic surface of endolysosomes. It resists destruction because it is under-ubiquitinated. Kit(D814Y) also appears in the endoplasmic reticulum soon after biosynthesis, and there, can activate STAT5 aberrantly. These mechanisms of oncogenic signalling are also seen in rat and human mast cell leukemia cells. Thus, oncogenic Kit signalling occurs from different intracellular compartments, and the mutation acts by altering Kit trafficking as well as activation. PMID:25493654

Molecular Genetic Study of Human Esophageal Carcinoma

DTIC Science & Technology

1991-07-16

chromosome 13q (Friend, et al. 1986; Lee, et al. 1987). The biochemical functions of the tumor suppressor gene products are not clearly elucidated...et al. 1990). In contrast to the dominant oncogenes, two genetic lesions are required for the manifestation of tumor suppressor gene , one each to...multiple genetic mutations. Oncogenes and tumor suppressor genes are frequently involved in the pathogenesis of human cancers. The transformation

Establishment and characterization of a human gastrointestinal stromal tumour (GIST) xenograft in athymic nude mice.

PubMed

Revheim, Mona-Elisabeth; Seierstad, Therese; Berner, Jeanne-Marie; Bruland, Oyvind Sverre; Røe, Kathrine; Ohnstad, Hege Oma; Bjerkehagen, Bodil; Bach-Gansmo, Tore

2009-11-01

The majority of gastrointestinal stromal tumours (GISTs) contain oncogenic KIT (v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog) or platelet-derived growth factor-alpha (PDGFRA) receptor tyrosine kinase (TK) mutations and are initially, but only temporarily sensitive to TK inhibitors. The aim of this study was to establish and characterize a human GIST xenograft that could be used for evaluating various molecularly targeted therapies. GIST tissue from four patients was implanted under the skin of athymic nude mice. In one case a tumour line was established. The xenograft showed characteristic GIST morphology and exhibited the same mutation profile as that of the patient. A human GIST xenograft with mutation in KIT exons 11 and 17 has been established and maintained in nude mice for 3 years (13 passages). This model will enable further studies on mechanisms of resistance, combination therapies and allow testing of novel targeted therapies.

USP21 regulates Hippo pathway activity by mediating MARK protein turnover.

PubMed

Nguyen, Hung Thanh; Kugler, Jan-Michael; Loya, Anand C; Cohen, Stephen M

2017-09-08

The Hippo pathway, which acts to repress the activity of YAP and TAZ trancriptional co-activators, serve as a barrier for oncogenic transformation. Unlike other oncoproteins, YAP and TAZ are rarely activated by mutations or amplified in cancer. However, elevated YAP/TAZ activity is frequently observed in cancer and often correlates with worse survival. The activity and stability of Hippo pathway components, including YAP/TAZ, AMOT and LATS1/2, are regulated by ubiquitin-mediated protein degradation. Aberrant expression of ubiquitin ligase complexes that regulate the turnover of Hippo components and deubiquitylating enzymes that counteract these ubiquitin ligases have been implicated in human cancer. Here we identify the USP21 deubiquitylating enzyme as a novel regulator of Hippo pathway activity. We provide evidence that USP21 regulates YAP/TAZ activity by controlling the stability of MARK kinases, which promote Hippo signaling. Low expression of USP21 in early stage renal clear cell carcinoma suggests that USP21 may be a useful biomarker.

Intestinal Stem Cell Dynamics: A Story of Mice and Humans.

PubMed

Hodder, Michael C; Flanagan, Dustin J; Sansom, Owen J

2018-06-01

Stem cell dynamics define the probability of accumulating mutations within the intestinal epithelium. In this issue of Cell Stem Cell, Nicholson et al. (2018) report that human intestinal stem cell dynamics differ significantly from those of mice and establish that oncogenic mutations are more likely to expand; therefore, "normal" epithelium may carry multiple mutations. Copyright © 2018 Elsevier Inc. All rights reserved.

Northwestern’s Kelleher Laboratory Develops Top-Down KRAS Isoform Assay to Detect Protein Mutations and Modifications | Office of Cancer Clinical Proteomics Research

Cancer.gov

Mutations in the RAS genes — KRAS, HRAS, and NRAS — have been identified in approximately 30% of all human cancers. While RAS gene family members encode proteins that are pivotal for cytoplasmic cell signaling, RAS oncogenes

Mutation-induced protein interaction kinetics changes affect apoptotic network dynamic properties and facilitate oncogenesis

PubMed Central

Zhao, Linjie; Sun, Tanlin; Pei, Jianfeng; Ouyang, Qi

2015-01-01

It has been a consensus in cancer research that cancer is a disease caused primarily by genomic alterations, especially somatic mutations. However, the mechanism of mutation-induced oncogenesis is not fully understood. Here, we used the mitochondrial apoptotic pathway as a case study and performed a systematic analysis of integrating pathway dynamics with protein interaction kinetics to quantitatively investigate the causal molecular mechanism of mutation-induced oncogenesis. A mathematical model of the regulatory network was constructed to establish the functional role of dynamic bifurcation in the apoptotic process. The oncogenic mutation enrichment of each of the protein functional domains involved was found strongly correlated with the parameter sensitivity of the bifurcation point. We further dissected the causal mechanism underlying this correlation by evaluating the mutational influence on protein interaction kinetics using molecular dynamics simulation. We analyzed 29 matched mutant–wild-type and 16 matched SNP—wild-type protein systems. We found that the binding kinetics changes reflected by the changes of free energy changes induced by protein interaction mutations, which induce variations in the sensitive parameters of the bifurcation point, were a major cause of apoptosis pathway dysfunction, and mutations involved in sensitive interaction domains show high oncogenic potential. Our analysis provided a molecular basis for connecting protein mutations, protein interaction kinetics, network dynamics properties, and physiological function of a regulatory network. These insights provide a framework for coupling mutation genotype to tumorigenesis phenotype and help elucidate the logic of cancer initiation. PMID:26170328

A mutation screening of oncogenes, tumor suppressor gene TP53 and nuclear encoded mitochondrial complex I genes in oncocytic thyroid tumors.

PubMed

Evangelisti, Cecilia; de Biase, Dario; Kurelac, Ivana; Ceccarelli, Claudio; Prokisch, Holger; Meitinger, Thomas; Caria, Paola; Vanni, Roberta; Romeo, Giovanni; Tallini, Giovanni; Gasparre, Giuseppe; Bonora, Elena

2015-03-21

Thyroid neoplasias with oncocytic features represent a specific phenotype in non-medullary thyroid cancer, reflecting the unique biological phenomenon of mitochondrial hyperplasia in the cytoplasm. Oncocytic thyroid cells are characterized by a prominent eosinophilia (or oxyphilia) caused by mitochondrial abundance. Although disruptive mutations in the mitochondrial DNA (mtDNA) are the most significant hallmark of such tumors, oncocytomas may be envisioned as heterogeneous neoplasms, characterized by multiple nuclear and mitochondrial gene lesions. We investigated the nuclear mutational profile of oncocytic tumors to pinpoint the mutations that may trigger the early oncogenic hit. Total DNA was extracted from paraffin-embedded tissues from 45 biopsies of oncocytic tumors. High-resolution melting was used for mutation screening of mitochondrial complex I subunits genes. Specific nuclear rearrangements were investigated by RT-PCR (RET/PTC) or on isolated nuclei by interphase FISH (PAX8/PPARγ). Recurrent point mutations were analyzed by direct sequencing. In our oncocytic tumor samples, we identified rare TP53 mutations. The series of analyzed cases did not include poorly- or undifferentiated thyroid carcinomas, and none of the TP53 mutated cases had significant mitotic activity or high-grade features. Thus, the presence of disruptive TP53 mutations was completely unexpected. In addition, novel mutations in nuclear-encoded complex I genes were identified. These findings suggest that nuclear genetic lesions altering the bioenergetics competence of thyroid cells may give rise to an aberrant mitochondria-centered compensatory mechanism and ultimately to the oncocytic phenotype.

PI3K: A Crucial Piece in the RAS Signaling Puzzle.

PubMed

Krygowska, Agata Adelajda; Castellano, Esther

2018-06-01

RAS proteins are key signaling switches essential for control of proliferation, differentiation, and survival of eukaryotic cells. RAS proteins are mutated in 30% of human cancers. In addition, mutations in upstream or downstream signaling components also contribute to oncogenic activation of the pathway. RAS proteins exert their functions through activation of several signaling pathways and dissecting the contributions of these effectors in normal cells and in cancer is an ongoing challenge. In this review, we summarize our current knowledge about how RAS regulates type I phosphatidylinositol 3-kinase (PI3K), one of the main RAS effectors. RAS signaling through PI3K is necessary for normal lymphatic vasculature development and for RAS-induced transformation in vitro and in vivo, especially in lung cancer, where it is essential for tumor initiation and necessary for tumor maintenance. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

Retinoic acid induces proteasome-dependent degradation of retinoic acid receptor α (RARα) and oncogenic RARα fusion proteins

PubMed Central

Zhu, Jun; Gianni, Maurizio; Kopf, Eliezer; Honoré, Nicole; Chelbi-Alix, Mounira; Koken, Marcel; Quignon, Frédérique; Rochette-Egly, Cécile; de Thé, Hugues

1999-01-01

Analyzing the pathways by which retinoic acid (RA) induces promyelocytic leukemia/retinoic acid receptor α (PML/RARα) catabolism in acute promyelocytic leukemia (APL), we found that, in addition to caspase-mediated PML/RARα cleavage, RA triggers degradation of both PML/RARα and RARα. Similarly, in non-APL cells, RA directly targeted RARα and RARα fusions to the proteasome degradation pathway. Activation of either RARα or RXRα by specific agonists induced degradation of both proteins. Conversely, a mutation in RARα that abolishes heterodimer formation and DNA binding, blocked both RARα and RXRα degradation. Mutations in the RARα DNA-binding domain or AF-2 transcriptional activation region also impaired RARα catabolism. Hence, our results link transcriptional activation to receptor catabolism and suggest that transcriptional up-regulation of nuclear receptors by their ligands may be a feedback mechanism allowing sustained target-gene activation. PMID:10611294

Inducible transgenics. New lessons on events governing the induction and commitment in mammary tumorigenesis.

PubMed

Hulit, J; Di Vizio, D; Pestell, R G

2001-01-01

Breast cancer arises from multiple genetic events that together contribute to the established, irreversible malignant phenotype. The development of inducible tissue-specific transgenics has allowed a careful dissection of the events required for induction and subsequent maintenance of tumorigenesis. Mammary gland targeted expression of oncogenic Ras or c-Myc is sufficient for the induction of mammary gland tumorigenesis in the rodent, and when overexpressed together the rate of tumor onset is substantially enhanced. In an exciting recent finding, D'Cruz et al discovered tetracycline-regulated c-Myc overexpression in the mammary gland induced invasive mammary tumors that regressed upon withdrawal of c-Myc expression. Almost one-half of the c-Myc-induced tumors harbored K-ras or N-ras gene point mutations, correlating with tumor persistence on withdrawal of c-Myc transgene expression. These findings suggest maintenance of tumorigenesis may involve a second mutation within the Ras pathway.

Developments for Personalized Medicine of Lung Cancer Subtypes: Mass Spectrometry-Based Clinical Proteogenomic Analysis of Oncogenic Mutations.

PubMed

Nishimura, Toshihide; Nakamura, Haruhiko

2016-01-01

Molecular therapies targeting lung cancers with mutated epidermal growth factor receptor (EGFR) by EGFR-tyrosin kinase inhibitors (EGFR-TKIs), gefitinib and erlotinib, changed the treatment system of lung cancer. It was revealed that drug efficacy differs by race (e.g., Caucasians vs. Asians) due to oncogenic driver mutations specific to each race, exemplified by gefitinib / erlotinib. The molecular target drugs for lung cancer with anaplastic lymphoma kinase (ALK) gene translocation (the fusion gene, EML4-ALK) was approved, and those targeting lung cancers addicted ROS1, RET, and HER2 have been under development. Both identification and quantification of gatekeeper mutations need to be performed using lung cancer tissue specimens obtained from patients to improve the treatment for lung cancer patients: (1) identification and quantitation data of targeted mutated proteins, including investigation of mutation heterogeneity within a tissue; (2) exploratory mass spectrometry (MS)-based clinical proteogenomic analysis of mutated proteins; and also importantly (3) analysis of dynamic protein-protein interaction (PPI) networks of proteins significantly related to a subgroup of patients with lung cancer not only with good efficacy but also with acquired resistance. MS-based proteogenomics is a promising approach to directly capture mutated and fusion proteins expressed in a clinical sample. Technological developments are further expected, which will provide a powerful solution for the stratification of patients and drug discovery (Precision Medicine).

Methylation-mediated miR-155-FAM133A axis contributes to the attenuated invasion and migration of IDH mutant gliomas.

PubMed

Huang, Guo-Hao; Du, Lei; Li, Ningning; Zhang, Ying; Xiang, Yan; Tang, Jun-Hai; Xia, Shuli; Zhang, Eric Erquan; Lv, Sheng-Qing

2018-06-06

Gliomas with isocitrate dehydrogenases genes mutation (IDH MT ) were found to be less aggressive than their wildtype (IDH WT ) counterparts. However, the mechanism remains unclear. The current study aims to investigate the role of silenced oncogenic microRNAs in IDH MT gliomas, which were largely ignored and may contribute to the less aggressive behavior of IDH MT gliomas. Microarrays, bioinformatics analysis of the data from TCGA and qPCR analysis of samples from our experimental cohort (LGG: IDH WT =10, IDH MT =31; GBM: IDH WT =34, IDH MT =9) were performed. The results show that miR-155 was consistently down-regulated in IDH MT gliomas. Establishment of IDH1 R132H overexpressing glioma cell line and bisulfite sequencing PCR suggested that miR-155 down-regulation was associated with IDH1 R132H mutation induced promoter CpG islands methylation. The cancer testis antigen FAM133A is a direct downstream target of miR-155 and is a negative regulator of glioma invasion and migration possibly by regulating matrix metallopeptidase 14 (MMP14). Together, we found that methylation-regulated miR-155-FAM133A axis may contribute to the attenuated invasion and migration of IDH MT gliomas by targeting MMP14. Copyright © 2018. Published by Elsevier B.V.

BCR-ABL1- positive chronic myeloid leukemia with erythrocytosis presenting as polycythemia vera: a case report.

PubMed

Cornea, Mihaela I Precup; Levrat, Emmanuel; Pugin, Paul; Betticher, Daniel C

2015-04-08

The World Health Organization classification of chronic myeloproliferative disease encompasses eight entities of bone marrow neoplasms, among them Breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1-positive chronic myeloid leukemia and polycythemia vera. Polycythemia vera requires, in the majority of cases (95%), the negativity of Breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1 rearrangement and the presence of the Janus kinase 2 mutation. We report a case of erythrocytosis as the primary manifestation of a chronic myeloid leukemia, with the presence of the Philadelphia chromosome and the Breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1 fusion gene, and in the absence of any Janus kinase 2 mutation. A 68-year-old Caucasian woman, with a history of cigarette consumption and obstructive sleep apnoea syndrome (undergoing continuous positive airway pressure treatment) had presented to our institution with fatigue and a hemoglobin level of 18.6g/L, with slight leukocytosis at 16G/L, and no other anomalies on her complete blood cell count. Examination of her arterial blood gases found only a slight hypoxemia; erythropoietin and ferritin levels were very low and could not explain a secondary erythrocytosis. Further analyses revealed the absence of any Janus kinase 2 mutation, thus excluding polycythemia vera. Taken together with a high vitamin B12 level, we conducted a Breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1 gene analysis and bone marrow cytogenetic analysis, both of which returned positive, leading to the diagnosis of chronic myeloid leukemia. To date, this case is the first description of a Breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1-positive chronic myeloid leukemia, presenting with erythrocytosis as the initial manifestation, and mimicking a Janus kinase 2 V617F-negative polycythemia vera. Her impressive response to imatinib therapy underscores the importance of not missing this diagnosis.

Prognostic and predictive values of oncogenic BRAF, NRAS, c-KIT and MITF in cutaneous and mucous melanoma.

PubMed

Pracht, M; Mogha, A; Lespagnol, A; Fautrel, A; Mouchet, N; Le Gall, F; Paumier, V; Lefeuvre-Plesse, C; Rioux-Leclerc, N; Mosser, J; Oger, E; Adamski, H; Galibert, M-D; Lesimple, T

2015-08-01

Mutations of BRAF, NRAS and c-KIT oncogenes are preferentially described in certain histological subtypes of melanoma and linked to specific histopathological features. BRAF-, MEK- and KIT-inhibitors led to improvement in overall survival of patients harbouring mutated metastatic melanoma. To assess the prevalence and types of BRAF, NRAS, c-KIT and MITF mutations in cutaneous and mucous melanoma and to correlate mutation status with clinicopathological features and outcome. Clinicopathological features and mutation status of 108 samples and of 98 consecutive patients were, respectively, assessed in one retrospective and one prospective study. Clinicopathological features were correlated with mutation status and the predictive value of these mutations was studied. This work identified significant correlations between BRAF mutations and melanoma occurring on non-chronic sun-damaged skin and superficial spreading melanoma (P < 0.05) on one hand, and between NRAS mutations and nodular melanoma (P < 0.05) on the other hand. Younger age (P < 0.05), microscopic (P < 0.05) and macroscopic (P < 0.05) lymphatic involvement at diagnosis of primary melanoma were significantly linked to BRAF mutations. A mutated status was a positive predictive factor of a response to BRAF inhibitors (OR = 3.44). Mutated melanoma showed a significantly (P = 0.038) higher objective response rate to cytotoxic chemotherapy (26.3%) than wild-type tumours (6.7%). Clinical and pathological characteristics of the primary melanoma differed between wild-type and BRAF- or NRAS-mutated tumours. Patients with BRAF-mutated tumours were younger at diagnosis of primary melanoma. Patients carrying mutations showed better responses better to specific kinase inhibitors and interestingly also to systemic cytotoxic chemotherapy. © 2015 European Academy of Dermatology and Venereology.

Type-1-cytokines synergize with oncogene inhibition to induce tumor growth arrest

PubMed Central

Acquavella, Nicolas; Clever, David; Yu, Zhiya; Roelke-Parker, Melody; Palmer, Douglas C.; Xi, Liqiang; Pflicke, Holger; Ji, Yun; Gros, Alena; Hanada, Ken-ichi; Goldlust, Ian S.; Mehta, Gautam U.; Klebanoff, Christopher A.; Crompton, Joseph G.; Sukumar, Madhusudhanan; Morrow, James J.; Franco, Zulmarie; Gattinoni, Luca; Liu, Hui; Wang, Ena; Marincola, Francesco; Stroncek, David F.; Lee, Chyi-Chia R.; Raffeld, Mark; Bosenberg, Marcus W.; Roychoudhuri, Rahul; Restifo, Nicholas P.

2014-01-01

Both targeted inhibition of oncogenic driver mutations and immune-based therapies show efficacy in treatment of patients with metastatic cancer but responses can be either short-lived or incompletely effective. Oncogene inhibition can augment the efficacy of immune-based therapy but mechanisms by which these two interventions might cooperate are incompletely resolved. Using a novel transplantable BRAFV600E-mutant murine melanoma model (SB-3123), we explore potential mechanisms of synergy between the selective BRAFV600E inhibitor vemurafenib and adoptive cell transfer (ACT)-based immunotherapy. We found that vemurafenib cooperated with ACT to delay melanoma progression without significantly affecting tumor infiltration or effector function of endogenous or adoptively transferred CD8+ T cells as previously observed. Instead, we found that the T-cell cytokines IFNγ and TNFα synergized with vemurafenib to induce cell-cycle arrest of tumor cells in vitro. This combinatorial effect was recapitulated in human melanoma-derived cell lines and was restricted to cancers bearing a BRAFV600E-mutation. Molecular profiling of treated SB-3123 indicated that the provision of vemurafenib promoted the sensitization of SB-3123 to the anti-proliferative effects of T-cell effector cytokines. The unexpected finding that immune cytokines synergize with oncogene inhibitors to induce growth arrest have major implications for understanding cancer biology at the intersection of oncogenic and immune signaling and provides a basis for design of combinatorial therapeutic approaches for patients with metastatic cancer. PMID:25358764

Signaling through the Phosphatidylinositol 3-Kinase (PI3K)/Mammalian Target of Rapamycin (mTOR) Axis Is Responsible for Aerobic Glycolysis mediated by Glucose Transporter in Epidermal Growth Factor Receptor (EGFR)-mutated Lung Adenocarcinoma*

PubMed Central

Makinoshima, Hideki; Takita, Masahiro; Saruwatari, Koichi; Umemura, Shigeki; Obata, Yuuki; Ishii, Genichiro; Matsumoto, Shingo; Sugiyama, Eri; Ochiai, Atsushi; Abe, Ryo; Goto, Koichi; Esumi, Hiroyasu; Tsuchihara, Katsuya

2015-01-01

Oncogenic epidermal growth factor receptor (EGFR) signaling plays an important role in regulating global metabolic pathways, including aerobic glycolysis, the pentose phosphate pathway (PPP), and pyrimidine biosynthesis. However, the molecular mechanism by which EGFR signaling regulates cancer cell metabolism is still unclear. To elucidate how EGFR signaling is linked to metabolic activity, we investigated the involvement of the RAS/MEK/ERK and PI3K/AKT/mammalian target of rapamycin (mTOR) pathways on metabolic alteration in lung adenocarcinoma (LAD) cell lines with activating EGFR mutations. Although MEK inhibition did not alter lactate production and the extracellular acidification rate, PI3K/mTOR inhibitors significantly suppressed glycolysis in EGFR-mutant LAD cells. Moreover, a comprehensive metabolomics analysis revealed that the levels of glucose 6-phosphate and 6-phosphogluconate as early metabolites in glycolysis and PPP were decreased after inhibition of the PI3K/AKT/mTOR pathway, suggesting a link between PI3K signaling and the proper function of glucose transporters or hexokinases in glycolysis. Indeed, PI3K/mTOR inhibition effectively suppressed membrane localization of facilitative glucose transporter 1 (GLUT1), which, instead, accumulated in the cytoplasm. Finally, aerobic glycolysis and cell proliferation were down-regulated when GLUT1 gene expression was suppressed by RNAi. Taken together, these results suggest that PI3K/AKT/mTOR signaling is indispensable for the regulation of aerobic glycolysis in EGFR-mutated LAD cells. PMID:26023239

Application of a multi-channel microfluidic chip on the simultaneous detection of DNAs by using microbead-quantum dots.

PubMed

Le, Ngoc Tam; Kim, Jong Sung

2014-12-01

Several researches have shown that cancer is caused by genetic mutations especially in genes involved in cell growth and regulation. Ras family members are frequently found in their mutated, oncogenic forms in human tumors. Mutant RAS proteins are constitutively active, owing to reduce intrinsic GTPase activity and insensitivity to GTPase-activating protein (GAPs). In total, activating mutations in the RAS genes occur in approximately 20% of all human cancers, mainly in codon 12, 13 or 61. Activating mutations in the NRAS gene not only result in the reduction of intrinsic GTPase activity but also in the induction of resistance against molecules inducing such activity. In this paper, we reported a rapid, simple and portable method for detecting the mutant types of NRAS genes codon 12 and 61 simultaneously by using bead-quantum dots (QDs) based multi-channel microfluidic chip. Probe DNAs are conjugated to bead-QDs and packed in the pillars of channels in the microfluidic chip. After injection of target DNAs and intercalating dyes, the fluorescence quenching of QDs by intercalating dye was observed due to FRET phenomena. The platform can be effortlessly applied in other biological and clinical areas.

Mapping the Structural and Dynamical Features of Multiple p53 DNA Binding Domains: Insights into Loop 1 Intrinsic Dynamics

PubMed Central

Lukman, Suryani; Lane, David P.; Verma, Chandra S.

2013-01-01

The transcription factor p53 regulates cellular integrity in response to stress. p53 is mutated in more than half of cancerous cells, with a majority of the mutations localized to the DNA binding domain (DBD). In order to map the structural and dynamical features of the DBD, we carried out multiple copy molecular dynamics simulations (totaling 0.8 μs). Simulations show the loop 1 to be the most dynamic element among the DNA-contacting loops (loops 1-3). Loop 1 occupies two major conformational states: extended and recessed; the former but not the latter displays correlations in atomic fluctuations with those of loop 2 (~24 Å apart). Since loop 1 binds to the major groove whereas loop 2 binds to the minor groove of DNA, our results begin to provide some insight into the possible mechanism underpinning the cooperative nature of DBD binding to DNA. We propose (1) a novel mechanism underlying the dynamics of loop 1 and the possible tread-milling of p53 on DNA and (2) possible mutations on loop 1 residues to restore the transcriptional activity of an oncogenic mutation at a distant site. PMID:24324553

Prebiotics: A Novel Approach to Treat Hepatocellular Carcinoma.

PubMed

Fatima, Naz; Akhtar, Tasleem; Sheikh, Nadeem

2017-01-01

Hepatocellular carcinoma is one of the fatal malignancies and is considered as the third leading cause of death. Mutations, genetic modifications, dietary aflatoxins, or impairments in the regulation of oncogenic pathways may bring about liver cancer. An effective barrier against hepatotoxins is offered by gut-liver axis as a change in gut permeability and expanded translocation of lipopolysaccharides triggers the activation of Toll-like receptors which stimulate the process of hepatocarcinogenesis. Prebiotics, nondigestible oligosaccharides, have a pivotal role to play when it comes to inducing an antitumor effect. A healthy gut flora balance is imperative to downregulation of inflammatory cytokines and reducing lipopolysaccharides induced endotoxemia, thus inducing the antitumor effect.

Depletion of pro-oncogenic RUNX2 enhances gemcitabine (GEM) sensitivity of p53-mutated pancreatic cancer Panc-1 cells through the induction of pro-apoptotic TAp63.

PubMed

Ozaki, Toshinori; Nakamura, Mizuyo; Ogata, Takehiro; Sang, Meijie; Yoda, Hiroyuki; Hiraoka, Kiriko; Sang, Meixiang; Shimozato, Osamu

2016-11-01

Recently, we have described that siRNA-mediated silencing of runt-related transcription factor 2 (RUNX2) improves anti-cancer drug gemcitabine (GEM) sensitivity of p53-deficient human pancreatic cancer AsPC-1 cells through the augmentation of p53 family TAp63-dependent cell death pathway. In this manuscript, we have extended our study to p53-mutated human pancreatic cancer Panc-1 cells. According to our present results, knockdown of mutant p53 alone had a marginal effect on GEM-mediated cell death of Panc-1 cells. We then sought to deplete RUNX2 using siRNA in Panc-1 cells and examined its effect on GEM sensitivity. Under our experimental conditions, RUNX2 knockdown caused a significant enhancement of GEM sensitivity of Panc-1 cells. Notably, GEM-mediated induction of TAp63 but not of TAp73 was further stimulated in RUNX2-depleted Panc-1 cells, indicating that, like AsPC-1 cells, TAp63 might play a pivotal role in the regulation of GEM sensitivity of Panc-1 cells. Consistent with this notion, forced expression of TAp63α in Panc-1 cells promoted cell cycle arrest and/or cell death, and massively increased luciferase activities driven by TAp63-target gene promoters such as p21WAF1 and NOXA. In addition, immunoprecipitation experiments indicated that RUNX2 forms a complex with TAp63 in Panc-1 cells. Taken together, our current observations strongly suggest that depletion of RUNX2 enhances the cytotoxic effect of GEM on p53-mutated Panc-1 cells through the stimulation of TAp63-dependent cell death pathway even in the presence of a large amount of pro-oncogenic mutant p53, and might provide an attractive strategy to treat pancreatic cancer patients with p53 mutations.

Depletion of pro-oncogenic RUNX2 enhances gemcitabine (GEM) sensitivity of p53-mutated pancreatic cancer Panc-1 cells through the induction of pro-apoptotic TAp63

PubMed Central

Ozaki, Toshinori; Nakamura, Mizuyo; Ogata, Takehiro; Sang, Meijie; Yoda, Hiroyuki; Hiraoka, Kiriko; Sang, Meixiang; Shimozato, Osamu

2016-01-01

Recently, we have described that siRNA-mediated silencing of runt-related transcription factor 2 (RUNX2) improves anti-cancer drug gemcitabine (GEM) sensitivity of p53-deficient human pancreatic cancer AsPC-1 cells through the augmentation of p53 family TAp63-dependent cell death pathway. In this manuscript, we have extended our study to p53-mutated human pancreatic cancer Panc-1 cells. According to our present results, knockdown of mutant p53 alone had a marginal effect on GEM-mediated cell death of Panc-1 cells. We then sought to deplete RUNX2 using siRNA in Panc-1 cells and examined its effect on GEM sensitivity. Under our experimental conditions, RUNX2 knockdown caused a significant enhancement of GEM sensitivity of Panc-1 cells. Notably, GEM-mediated induction of TAp63 but not of TAp73 was further stimulated in RUNX2-depleted Panc-1 cells, indicating that, like AsPC-1 cells, TAp63 might play a pivotal role in the regulation of GEM sensitivity of Panc-1 cells. Consistent with this notion, forced expression of TAp63α in Panc-1 cells promoted cell cycle arrest and/or cell death, and massively increased luciferase activities driven by TAp63-target gene promoters such as p21WAF1 and NOXA. In addition, immunoprecipitation experiments indicated that RUNX2 forms a complex with TAp63 in Panc-1 cells. Taken together, our current observations strongly suggest that depletion of RUNX2 enhances the cytotoxic effect of GEM on p53-mutated Panc-1 cells through the stimulation of TAp63-dependent cell death pathway even in the presence of a large amount of pro-oncogenic mutant p53, and might provide an attractive strategy to treat pancreatic cancer patients with p53 mutations. PMID:27713122

Oncogenic c-Myc-induced lymphomagenesis is inhibited non-redundantly by the p19Arf–Mdm2–p53 and RP–Mdm2–p53 pathways

PubMed Central

Meng, X; Carlson, NR; Dong, J; Zhang, Y

2016-01-01

The multifaceted oncogene c-Myc plays important roles in the development and progression of human cancer. Recent in vitro and in vivo studies have shown that the p19Arf–Mdm2–p53 and the ribosomal protein (RP)–Mdm2–p53 pathways are both essential in preventing oncogenic c-Myc-induced tumorigenesis. Disruption of each pathway individually by p19Arf deletion or by Mdm2C305F mutation, which disrupts RP-Mdm2 binding, accelerates Eμ-myc transgene-induced pre-B/B-cell lymphoma in mice at seemingly similar paces with median survival around 10 and 11 weeks, respectively, compared to 20 weeks for Eμ-myc transgenic mice. Because p19Arf can inhibit ribosomal biogenesis through its interaction with nucleophosmin (NPM/B23), RNA helicase DDX5 and RNA polymerase I transcription termination factor (TTF-I), it has been speculated that the p19Arf–Mdm2–p53 and the RP–Mdm2–p53 pathways might be a single p19Arf–RP–Mdm2–p53 pathway, in which p19Arf activates p53 by inhibiting RP biosynthesis; thus, p19Arf deletion or Mdm2C305F mutation would result in similar consequences. Here, we generated mice with concurrent p19Arf deletion and Mdm2C305F mutation and investigated the compound mice for tumorigenesis in the absence and the presence of oncogenic c-Myc overexpression. In the absence of Eμ-myc transgene, the Mdm2C305F mutation did not elicit spontaneous tumors in mice, nor did it accelerate spontaneous tumors in mice with p19Arf deletion. In the presence of Eμ-myc transgene, however, Mdm2C305F mutation significantly accelerated p19Arf deletion-induced lymphomagenesis and promoted rapid metastasis. We found that when p19Arf–Mdm2–p53 and RP–Mdm2–p53 pathways are independently disrupted, oncogenic c-Myc-induced p53 stabilization and activation is only partially attenuated. When both pathways are concurrently disrupted, however, c-Myc-induced p53 stabilization and activation are essentially obliterated. Thus, the p19Arf–Mdm2–p53 and the RP–Mdm2–p53 are non-redundant pathways possessing similar capabilities to activate p53 upon c-Myc overexpression. PMID:25823025

Concomitance of oncogenic HPV types, CHEK2 gene mutations, and CYP1B1 gene polymorphism as an increased risk factor for malignancy.

PubMed

Banaszkiewicz, Monika; Constantinou, Maria; Pietrusiński, Michał; Kępczyński, Lukasz; Jędrzejczyk, Adam; Rożniecki, Marek; Marks, Piotr; Kałużewski, Bogdan

2013-01-01

Urinary bladder carcinoma ranks the fourth position in malignancy incidence rates in men (6.1%) and the 17th position in women (1.6%). In general, neoplastic diseases should be approached from two perspectives: prevention with implementation of prophylactic measures and early diagnostics. Prophylactics is possible in the preclinical phase of neoplasm, being both justified and plausible in patients from high-risk groups. Thus, it is particularly important to select such groups, not only by referring to environmental carcinogenic factors (occupational and extra-occupational) but also from genetic predisposition, which may be conductive for neoplasm formation. The mutations / polymorphisms of CHEK2 and CYP1B1 genes predispose to neoplasm via multiorgan mechanisms, while the human papilloma virus (HPV) may participate in the neoplastic transformation as an environmental factor. 131 patients with diagnosed urinary bladder cancer were qualified to the study. Mutations/polymorphisms of CHEK2 (IVS2 + 1G > A gene, 1100delC, del5395, I157T) and CYP1B1- 355T/T were identified by the PCR in DNA isolated directly from the tumor and from peripheral blood. The ELISA test was used for the studies of 37 HPV genotypes in DNA, isolated tumour tissue. 11 mutations of CHEK2 gene were found, 355T/T polymorphism if CYP1B1 gene occurred in 18 patients (12.9%). Oncogenic HPV was found in 36 (29.3%), out of 123 examined patients. The concomitance of CHEK2 gene mutations or 355T/T polymorphism of CYP1B1 gene and the presence of oncogenic HPV types statistically significantly correlates with histological malignancy grades of urinary bladder carcinoma.

Pak and Rac GTPases promote oncogenic KIT–induced neoplasms

PubMed Central

Martin, Holly; Mali, Raghuveer Singh; Ma, Peilin; Chatterjee, Anindya; Ramdas, Baskar; Sims, Emily; Munugalavadla, Veerendra; Ghosh, Joydeep; Mattingly, Ray R.; Visconte, Valeria; Tiu, Ramon V.; Vlaar, Cornelis P.; Dharmawardhane, Suranganie; Kapur, Reuben

2013-01-01

An acquired somatic mutation at codon 816 in the KIT receptor tyrosine kinase is associated with poor prognosis in patients with systemic mastocytosis and acute myeloid leukemia (AML). Treatment of leukemic cells bearing this mutation with an allosteric inhibitor of p21–activated kinase (Pak) or its genetic inactivation results in growth repression due to enhanced apoptosis. Inhibition of the upstream effector Rac abrogates the oncogene-induced growth and activity of Pak. Although both Rac1 and Rac2 are constitutively activated via the guanine nucleotide exchange factor (GEF) Vav1, loss of Rac1 or Rac2 alone moderately corrected the growth of KIT-bearing leukemic cells, whereas the combined loss resulted in 75% growth repression. In vivo, the inhibition of Vav or Rac or Pak delayed the onset of myeloproliferative neoplasms (MPNs) and corrected the associated pathology in mice. To assess the role of Rac GEFs in oncogene-induced transformation, we used an inhibitor of Rac, EHop-016, which specifically targets Vav1 and found that EHop-016 was a potent inhibitor of human and murine leukemic cell growth. These studies identify Pak and Rac GTPases, including Vav1, as potential therapeutic targets in MPN and AML involving an oncogenic form of KIT. PMID:24091327

Oncogenic Mutations Differentially Affect Bax Monomer, Dimer, and Oligomeric Pore Formation in the Membrane.

PubMed

Zhang, Mingzhen; Zheng, Jie; Nussinov, Ruth; Ma, Buyong

2016-09-15

Dysfunction of Bax, a pro-apoptotic regulator of cellular metabolism is implicated in neurodegenerative diseases and cancer. We have constructed the first atomistic models of the Bax oligomeric pore consisting with experimental residue-residue distances. The models are stable, capturing well double electron-electron resonance (DEER) spectroscopy measurements and provide structural details in line with the DEER data. Comparison with the latest experimental results revealed that our models agree well with both Bax and Bak pores, pointed to a converged structural arrangement for Bax and Bak pore formation. Using multi-scale molecular dynamics simulations, we probed mutational effects on Bax transformation from monomer → dimer → membrane pore formation at atomic resolution. We observe that two cancer-related mutations, G40E and S118I, allosterically destabilize the monomer and stabilize an off-pathway swapped dimer, preventing productive pore formation. This observation suggests a mechanism whereby the mutations may work mainly by over-stabilizing the monomer → dimer transformation toward an unproductive off-pathway swapped-dimer state. Our observations point to misfolded Bax states, shedding light on the molecular mechanism of Bax mutation-elicited cancer. Most importantly, the structure of the Bax pore facilitates future study of releases cytochrome C in atomic detail.

Oncogenic Mutations Differentially Affect Bax Monomer, Dimer, and Oligomeric Pore Formation in the Membrane

NASA Astrophysics Data System (ADS)

Zhang, Mingzhen; Zheng, Jie; Nussinov, Ruth; Ma, Buyong

2016-09-01

Dysfunction of Bax, a pro-apoptotic regulator of cellular metabolism is implicated in neurodegenerative diseases and cancer. We have constructed the first atomistic models of the Bax oligomeric pore consisting with experimental residue-residue distances. The models are stable, capturing well double electron-electron resonance (DEER) spectroscopy measurements and provide structural details in line with the DEER data. Comparison with the latest experimental results revealed that our models agree well with both Bax and Bak pores, pointed to a converged structural arrangement for Bax and Bak pore formation. Using multi-scale molecular dynamics simulations, we probed mutational effects on Bax transformation from monomer → dimer → membrane pore formation at atomic resolution. We observe that two cancer-related mutations, G40E and S118I, allosterically destabilize the monomer and stabilize an off-pathway swapped dimer, preventing productive pore formation. This observation suggests a mechanism whereby the mutations may work mainly by over-stabilizing the monomer → dimer transformation toward an unproductive off-pathway swapped-dimer state. Our observations point to misfolded Bax states, shedding light on the molecular mechanism of Bax mutation-elicited cancer. Most importantly, the structure of the Bax pore facilitates future study of releases cytochrome C in atomic detail.

Imatinib for melanomas harboring mutationally activated or amplified KIT arising on mucosal, acral, and chronically sun-damaged skin.

PubMed

Hodi, F Stephen; Corless, Christopher L; Giobbie-Hurder, Anita; Fletcher, Jonathan A; Zhu, Meijun; Marino-Enriquez, Adrian; Friedlander, Philip; Gonzalez, Rene; Weber, Jeffrey S; Gajewski, Thomas F; O'Day, Steven J; Kim, Kevin B; Lawrence, Donald; Flaherty, Keith T; Luke, Jason J; Collichio, Frances A; Ernstoff, Marc S; Heinrich, Michael C; Beadling, Carol; Zukotynski, Katherine A; Yap, Jeffrey T; Van den Abbeele, Annick D; Demetri, George D; Fisher, David E

2013-09-10

Amplifications and mutations in the KIT proto-oncogene in subsets of melanomas provide therapeutic opportunities. We conducted a multicenter phase II trial of imatinib in metastatic mucosal, acral, or chronically sun-damaged (CSD) melanoma with KIT amplifications and/or mutations. Patients received imatinib 400 mg once per day or 400 mg twice per day if there was no initial response. Dose reductions were permitted for treatment-related toxicities. Additional oncogene mutation screening was performed by mass spectroscopy. Twenty-five patients were enrolled (24 evaluable). Eight patients (33%) had tumors with KIT mutations, 11 (46%) with KIT amplifications, and five (21%) with both. Median follow-up was 10.6 months (range, 3.7 to 27.1 months). Best overall response rate (BORR) was 29% (21% excluding nonconfirmed responses) with a two-stage 95% CI of 13% to 51%. BORR was significantly greater than the hypothesized null of 5% and statistically significantly different by mutation status (7 of 13 or 54% KIT mutated v 0% KIT amplified only). There were no statistical differences in rates of progression or survival by mutation status or by melanoma site. The overall disease control rate was 50% but varied significantly by KIT mutation status (77% mutated v 18% amplified). Four patients harbored pretreatment NRAS mutations, and one patient acquired increased KIT amplification after treatment. Melanomas that arise on mucosal, acral, or CSD skin should be assessed for KIT mutations. Imatinib can be effective when tumors harbor KIT mutations, but not if KIT is amplified only. NRAS mutations and KIT copy number gain may be mechanisms of therapeutic resistance to imatinib.

Exploring environmental causes of altered ras effects: fragmentation plus integration?

PubMed

Porta, Miquel; Ayude, Daniel; Alguacil, Juan; Jariod, Manuel

2003-02-01

Mutations in ras genes are the most common abnormality of oncogenes in human cancer and a major example of activation by point mutation. Experimental and epidemiological studies support the notion that Ki-ras activation and expression may be chemically related. We discuss the potential role of several environmental compounds in the induction or promotion of ras mutations in humans, with a focus on exocrine pancreatic cancer, the human tumor with the highest prevalence at diagnosis of Ki-ras mutations. Organochlorine compounds, organic solvents, and coffee compounds may play an indirect role in causing Ki-ras mutations, rather than as direct inducers of the mutations. Although for some organochlorine compounds the induction of point mutations in ras oncogenes cannot be excluded, it seems more likely that the effects of these compounds are mediated through nongenomic or indirectly genotoxic mechanisms of action. Organic solvents also may act via enzymatic induction of ras mutagens or by providing a proliferation advantage to ras-mutated cell clones. In exocrine pancreatic cancer, caffeine, other coffee compounds, or other factors with which coffee drinking is associated could modulate Ki-ras activation by interfering with DNA repair, cell-cycle checkpoints, and apoptosis. Asbestos, cigarette smoking, and some dietary factors also may be involved in the initiation or the promotion of Ki-ras mutations in lung and colon cancers. Further development of the mechanistic scenarios proposed here could contribute to a meaningful integration of biological, clinical, and environmental knowledge on the causes of altered ras effects. Copyright 2003 Wiley-Liss, Inc.

Identification of T-cell Receptors Targeting KRAS-mutated Human Tumors

PubMed Central

Wang, Qiong J.; Yu, Zhiya; Griffith, Kayla; Hanada, Ken-ichi; Restifo, Nicholas P.; Yang, James C.

2015-01-01

KRAS is one of the most frequently mutated proto-oncogenes in human cancers. The dominant oncogenic mutations of KRAS are single amino acid substitutions at codon 12, in particular G12D and G12V present in 60–70% of pancreatic cancers and 20–30% of colorectal cancers. The consistency, frequency, and tumor specificity of these “neo-antigens” make them attractive therapeutic targets. Recent data associates T cells that target mutated antigens with clinical immunotherapy responses in patients with metastatic melanoma, lung cancer, or cholangiocarcinoma. Using HLA-peptide prediction algorithms, we noted that HLA-A*11:01 could potentially present mutated KRAS variants. By immunizing HLA-A*11:01 transgenic mice, we generated murine T cells and subsequently isolated T-cell receptors (TCRs) highly reactive to the mutated KRAS variants G12V and G12D. Peripheral blood lymphocytes (PBLs) transduced with these TCRs could recognize multiple HLA-A*11:01+ tumor lines bearing the appropriate KRAS mutations. In a xenograft model of large established tumor, adoptive transfer of these transduced PBLs reactive with an HLA-A*11:01, G12D-mutated pancreatic cell line could significantly reduce its growth in NSG mice (P = 0.002). The success of adoptive transfer of TCR-engineered T cells against melanoma and other cancers support clinical trials with these T cells that recognize mutated KRAS in patients with a variety of common cancer types. PMID:26701267

Brain Metastases in Oncogene-Addicted Non-Small Cell Lung Cancer Patients: Incidence and Treatment

PubMed Central

Remon, J.; Besse, Benjamin

2018-01-01

Brain metastases (BM) are common in non-small cell lung cancer patients including in molecularly selected populations, such as EGFR-mutant and ALK-rearranged tumors. They are associated with a reduced quality of life, and are commonly the first site of progression for patients receiving tyrosine kinase inhibitors (TKIs). In this review, we summarize incidence of BM and intracranial efficacy with TKI agents according to oncogene driver mutations, focusing on important clinical issues, notably optimal first-line treatment in oncogene-addicted lung tumors with upfront BM (local therapies followed by TKI vs. TKI monotherapy). We also discuss the potential role of newly emerging late-generation TKIs as new standard treatment in oncogene-addicted lung cancer tumors compared with sequential strategies. PMID:29696132

Oncogenically active MYD88 mutations in human lymphoma.

PubMed

Ngo, Vu N; Young, Ryan M; Schmitz, Roland; Jhavar, Sameer; Xiao, Wenming; Lim, Kian-Huat; Kohlhammer, Holger; Xu, Weihong; Yang, Yandan; Zhao, Hong; Shaffer, Arthur L; Romesser, Paul; Wright, George; Powell, John; Rosenwald, Andreas; Muller-Hermelink, Hans Konrad; Ott, German; Gascoyne, Randy D; Connors, Joseph M; Rimsza, Lisa M; Campo, Elias; Jaffe, Elaine S; Delabie, Jan; Smeland, Erlend B; Fisher, Richard I; Braziel, Rita M; Tubbs, Raymond R; Cook, J R; Weisenburger, Denny D; Chan, Wing C; Staudt, Louis M

2011-02-03

The activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) remains the least curable form of this malignancy despite recent advances in therapy. Constitutive nuclear factor (NF)-κB and JAK kinase signalling promotes malignant cell survival in these lymphomas, but the genetic basis for this signalling is incompletely understood. Here we describe the dependence of ABC DLBCLs on MYD88, an adaptor protein that mediates toll and interleukin (IL)-1 receptor signalling, and the discovery of highly recurrent oncogenic mutations affecting MYD88 in ABC DLBCL tumours. RNA interference screening revealed that MYD88 and the associated kinases IRAK1 and IRAK4 are essential for ABC DLBCL survival. High-throughput RNA resequencing uncovered MYD88 mutations in ABC DLBCL lines. Notably, 29% of ABC DLBCL tumours harboured the same amino acid substitution, L265P, in the MYD88 Toll/IL-1 receptor (TIR) domain at an evolutionarily invariant residue in its hydrophobic core. This mutation was rare or absent in other DLBCL subtypes and Burkitt's lymphoma, but was observed in 9% of mucosa-associated lymphoid tissue lymphomas. At a lower frequency, additional mutations were observed in the MYD88 TIR domain, occurring in both the ABC and germinal centre B-cell-like (GCB) DLBCL subtypes. Survival of ABC DLBCL cells bearing the L265P mutation was sustained by the mutant but not the wild-type MYD88 isoform, demonstrating that L265P is a gain-of-function driver mutation. The L265P mutant promoted cell survival by spontaneously assembling a protein complex containing IRAK1 and IRAK4, leading to IRAK4 kinase activity, IRAK1 phosphorylation, NF-κB signalling, JAK kinase activation of STAT3, and secretion of IL-6, IL-10 and interferon-β. Hence, the MYD88 signalling pathway is integral to the pathogenesis of ABC DLBCL, supporting the development of inhibitors of IRAK4 kinase and other components of this pathway for the treatment of tumours bearing oncogenic MYD88 mutations.

The genetics and biology of KRAS in lung cancer

PubMed Central

Westcott, Peter M. K.; To, Minh D.

2013-01-01

Mutational activation of KRAS is a common oncogenic event in lung cancer and other epithelial cancer types. Efforts to develop therapies that counteract the oncogenic effects of mutant KRAS have been largely unsuccessful, and cancers driven by mutant KRAS remain among the most refractory to available treatments. Studies undertaken over the past decades have produced a wealth of information regarding the clinical relevance of KRAS mutations in lung cancer. Mutant Kras-driven mouse models of cancer, together with cellular and molecular studies, have provided a deeper appreciation for the complex functions of KRAS in tumorigenesis. However, a much more thorough understanding of these complexities is needed before clinically effective therapies targeting mutant KRAS-driven cancers can be achieved. PMID:22776234

Aberrant RNA splicing in cancer; expression changes and driver mutations of splicing factor genes.

PubMed

Sveen, A; Kilpinen, S; Ruusulehto, A; Lothe, R A; Skotheim, R I

2016-05-12

Alternative splicing is a widespread process contributing to structural transcript variation and proteome diversity. In cancer, the splicing process is commonly disrupted, resulting in both functional and non-functional end-products. Cancer-specific splicing events are known to contribute to disease progression; however, the dysregulated splicing patterns found on a genome-wide scale have until recently been less well-studied. In this review, we provide an overview of aberrant RNA splicing and its regulation in cancer. We then focus on the executors of the splicing process. Based on a comprehensive catalog of splicing factor encoding genes and analyses of available gene expression and somatic mutation data, we identify cancer-associated patterns of dysregulation. Splicing factor genes are shown to be significantly differentially expressed between cancer and corresponding normal samples, and to have reduced inter-individual expression variation in cancer. Furthermore, we identify enrichment of predicted cancer-critical genes among the splicing factors. In addition to previously described oncogenic splicing factor genes, we propose 24 novel cancer-critical splicing factors predicted from somatic mutations.

Role of specific DNA mutations in the peripheral blood of colorectal cancer patients for the assessment of tumor stage and residual disease following tumor resection

PubMed Central

Norcic, Gregor; Jelenc, Franc; Cerkovnik, Petra; Stegel, Vida; Novakovic, Srdjan

2016-01-01

In the present study, the detection of tumor-specific KRAS proto-oncogene, GTPase (KRAS) and B-Raf proto-oncogene, serine/threonine kinase (BRAF) mutations in the peripheral blood of colorectal cancer (CRC) patients at all stages and adenomas was used for the estimation of disease stage prior to surgery and for residual disease following surgery. A total of 65 CRC patients were enrolled. The primary tumor tested positive for the specific mutations (KRAS mutations in codons 12, 13, 61, 117 or 146 and BRAF mutations in codon 600) in 35 patients. In all these patients, the specimen of normal bowel resected with the tumor was also tested for the presence of the same mutations in order to exclude the germ-line mutations. Only patients who tested positive for the specific mutation in the primary tumor were included in further analysis for the presence of tumor-specific mutation in the peripheral blood. No statistically significant differences were found between the detection rates of tumor mutations in the blood and different tumor stages (P=0.491). However, statistically significant differences in the proportions of patients with detected tumor-specific DNA mutations in the peripheral blood were found when comparing the groups of patients with R0 and R2 resections (P=0.038). Tumor-specific DNA mutations in the peripheral blood were more frequently detected in the patients with an incomplete surgical clearance of the tumor due to macroscopic residual disease (R2 resections). Therefore, the study concludes that the follow-up of somatic KRAS- and BRAF-mutated DNA in the peripheral blood of CRC patients may be useful in assessing the surgical clearance of the disease. PMID:27900004

Concurrent Targeting of KRAS and AKT by MiR-4689 Is a Novel Treatment Against Mutant KRAS Colorectal Cancer

PubMed Central

Hiraki, Masayuki; Nishimura, Junichi; Takahashi, Hidekazu; Wu, Xin; Takahashi, Yusuke; Miyo, Masaaki; Nishida, Naohiro; Uemura, Mamoru; Hata, Taishi; Takemasa, Ichiro; Mizushima, Tsunekazu; Soh, Jae-Won; Doki, Yuichiro; Mori, Masaki; Yamamoto, Hirofumi

2015-01-01

KRAS mutations are a major cause of drug resistance to molecular-targeted therapies. Aberrant epidermal growth factor receptor (EGFR) signaling may cause dysregulation of microRNA (miRNA) and gene regulatory networks, which leads to cancer initiation and progression. To address the functional relevance of miRNAs in mutant KRAS cancers, we transfected exogenous KRASG12V into human embryonic kidney 293 and MRC5 cells with wild-type KRAS and BRAF genes, and we comprehensively profiled the dysregulated miRNAs. The result showed that mature miRNA oligonucleotide (miR)-4689, one of the significantly down-regulated miRNAs in KRASG12V overexpressed cells, was found to exhibit a potent growth-inhibitory and proapoptotic effect both in vitro and in vivo. miR-4689 expression was significantly down-regulated in cancer tissues compared to normal mucosa, and it was particularly decreased in mutant KRAS CRC tissues. miR-4689 directly targets v-ki-ras2 kirsten rat sarcoma viral oncogene homolog (KRAS) and v-akt murine thymoma viral oncogene homolog 1(AKT1), key components of two major branches in EGFR pathway, suggesting KRAS overdrives this signaling pathway through inhibition of miR-4689. Overall, this study provided additional evidence that mutant KRAS functions as a broad regulator of the EGFR signaling cascade by inhibiting miR-4689, which negatively regulates both RAS/mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/AKT pathways. These activities indicated that miR-4689 may be a promising therapeutic agent in mutant KRAS CRC. PMID:25756961

Roles of p53, MYC and HIF-1 in regulating glycolysis - the seventh hallmark of cancer.

PubMed

Yeung, S J; Pan, J; Lee, M-H

2008-12-01

Despite diversity in genetic events in oncogenesis, cancer cells exhibit a common set of functional characteristics. Otto Warburg discovered that cancer cells have consistently higher rates of glycolysis than normal cells. The underlying mechanisms leading to the Warburg phenomenon include mitochondrial changes, upregulation of rate-limiting enzymes/proteins in glycolysis and intracellular pH regulation, hypoxia-induced switch to anaerobic metabolism, and metabolic reprogramming after loss of p53 function. The regulation of energy metabolism can be traced to a "triad" of transcription factors: c-MYC, HIF-1 and p53. Oncogenetic changes involve a nonrandom set of gene deletions, amplifications and mutations, and many oncogenes and tumor suppressor genes cluster along the signaling pathways that regulate c-MYC, HIF-1 and p53. Glycolysis in cancer cells has clinical implications in cancer diagnosis, treatment and interaction with diabetes mellitus. Many drugs targeting energy metabolism are in development. Future advances in technology may bring about transcriptome and metabolome-guided chemotherapy.

Indispensable roles of mammalian Cbl family proteins as negative regulators of protein tyrosine kinase signaling

PubMed Central

Band, Vimla

2011-01-01

All higher eukaryotes utilize protein tyrosine kinases (PTKs) as molecular switches to control a variety of cellular signals. Notably, many PTKs have been identified as proto-oncogenes whose aberrant expression, mutations or co-option by pathogens can lead to human malignancies. Thus, it is obvious that PTK functions must be precisely regulated in order to maintain homeostasis of an organism. Investigations over the past fifteen years have revealed that members of the Cbl family proteins can serve as negative regulators of PTK signaling, and biochemical and cell biological studies have unraveled the mechanistic basis of this regulation. Yet, it is only recently that the field has begun to appreciate the real significance of this novel regulatory apparatus in shaping PTK-mediated signaling in organismic contexts and in human diseases. Here, we discuss recent progress in murine models that are beginning to provide insights into the critical roles of Cbl proteins in physiological pathways, with important implications in understanding how aberrations of Cbl proteins contribute to oncogenesis. PMID:21655429

Fendiline Inhibits K-Ras Plasma Membrane Localization and Blocks K-Ras Signal Transmission

PubMed Central

van der Hoeven, Dharini; Cho, Kwang-jin; Ma, Xiaoping; Chigurupati, Sravanthi; Parton, Robert G.

2013-01-01

Ras proteins regulate signaling pathways important for cell growth, differentiation, and survival. Oncogenic mutant Ras proteins are commonly expressed in human tumors, with mutations of the K-Ras isoform being most prevalent. To be active, K-Ras must undergo posttranslational processing and associate with the plasma membrane. We therefore devised a high-content screening assay to search for inhibitors of K-Ras plasma membrane association. Using this assay, we identified fendiline, an L-type calcium channel blocker, as a specific inhibitor of K-Ras plasma membrane targeting with no detectable effect on the localization of H- and N-Ras. Other classes of L-type calcium channel blockers did not mislocalize K-Ras, suggesting a mechanism that is unrelated to calcium channel blockade. Fendiline did not inhibit K-Ras posttranslational processing but significantly reduced nanoclustering of K-Ras and redistributed K-Ras from the plasma membrane to the endoplasmic reticulum (ER), Golgi apparatus, endosomes, and cytosol. Fendiline significantly inhibited signaling downstream of constitutively active K-Ras and endogenous K-Ras signaling in cells transformed by oncogenic H-Ras. Consistent with these effects, fendiline blocked the proliferation of pancreatic, colon, lung, and endometrial cancer cell lines expressing oncogenic mutant K-Ras. Taken together, these results suggest that inhibitors of K-Ras plasma membrane localization may have utility as novel K-Ras-specific anticancer therapeutics. PMID:23129805

[Clinical relevance of the K-ras oncogene in colorectal cancer: experience in a Mexican population].

PubMed

Cabrera-Mendoza, F; Gainza-Lagunes, S; Castañeda-Andrade, I; Castro-Zárate, A

2014-01-01

Colorectal cancer is frequent in the developed countries, with a cancer-specific mortality rate of 33%. Different biomarkers are associated with overall survival and the prediction of monoclonal treatment effectiveness. The presence of mutations in the K-ras oncogene alters the response to target therapy with cetuximab and could be an independent prognostic factor. To analyze the difference in survival between patients with mutated K-ras and those with K-ras wild-type status. Thirty-one clinical records were retrospectively analyzed of patients presenting with colorectal cancer that underwent K-ras sequencing through real-time polymerase chain reaction within the time frame of 2009 to 2012 at the Hospital de Alta Especialidad de Veracruz of the Instituto para la Salud y Seguridad Social de los Trabajadores del Estado (HAEV-ISSSTE). Survival analysis for patients with and without K-ras mutation was performed using the Kaplan Meier method. Contrast of covariates was performed using logarithmic transformations. No statistically significant difference was found in relation to survival in the patients with mutated K-ras vs. those with K-ras wild-type (P=.416), nor were significant differences found when analyzing the covariants and survival in the patients with mutated K-ras: ECOG scale (P=.221); age (less than, equal to or greater than 65years, P=.441); clinical stage according to the AJCC (P=.057), and primary lesion site (P=.614). No relation was found between the K-ras oncogene mutation and reduced survival, in contrast to what has been established in the international medical literature. Further studies that include both a larger number of patients and those receiving monoclonal treatment, need to be conducted. There were only 5 patients in the present study that received cetuximab, resulting in a misleading analysis. Copyright © 2013 Asociación Mexicana de Gastroenterología. Published by Masson Doyma México S.A. All rights reserved.

Baseline and On-Treatment Characteristics of Serum Tumor Markers in Stage IV Oncogene-Addicted Adenocarcinoma of the Lung.

PubMed

Noonan, Sinead A; Patil, Tejas; Gao, Dexiang; King, Gentry G; Thibault, Jessica R; Lu, Xian; Bunn, Paul A; Doebele, Robert C; Purcell, W Thomas; Barón, Anna E; Camidge, D Ross

2018-01-01

The role of serum tumor markers in the modern management of advanced NSCLC remains poorly described. A single-center retrospective analysis of available carcinoembryonic antigen, CA125, CA19.9, and CA27.29 levels at baseline and during treatment of stage IV lung adenocarcinoma by oncogenic driver was conducted. A total of 142 patients were analyzed (60 with anaplastic lymphoma kinase gene [ALK] rearrangement, 50 with EGFR mutation, four with ROS1 rearrangement, and 29 with KRAS mutation). Of these, 82% had at least one marker (95% if all four markers were measured), with CA27.29 being the most commonly increased and CA19.9 the rarest. Only CA27.29 differed significantly by oncogene (it was less common in KRAS) (p = 0.016). The median times to nadir during tyrosine kinase inhibitor (TKI) therapy in EGFR and ALK cases were 16.4 and 20 weeks, respectively. Of the 41 patients with EGFR mutation or ALK or ROS1 rearrangement, 24 (59%) demonstrated an initial increase within the first 4 weeks of TKI therapy, 58% of whom then had their levels fall below baseline. An increase in marker level of 10% or more from nadir occurred in 53% of systemic and 22% of central nervous system-only progression. Serum tumor markers are frequently increased in lung adenocarcinoma regardless of driver oncogene. Changes within the first 4 weeks of therapy may be misleading. Progression is associated with marker increases, especially in sites other than the central nervous system. Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Temporal Resolution of Autophosphorylation for Normal and Oncogenic Forms of EGFR and Differential Effects of Gefitinib†

PubMed Central

Kim, Youngjoo; Li, Zhimin; Apetri, Mihaela; Luo, BeiBei; Settleman, Jeffrey E.; Anderson, Karen S.

2012-01-01

Epidermal growth factor receptor (EGFR) is a member of the ErbB family of receptor tyrosine kinases (RTK). EGFR overexpression or mutation in many different forms of cancers has highlighted its role as an important therapeutic target. Gefitinib, the first small molecule inhibitor of EGFR kinase function to be approved for the treatment of non-small cell lung cancer (NSCLC) by the FDA, demonstrates clinical activity primarily in patients with tumors that harbor somatic kinase domain mutations in EGFR. Here, we compare wild-type EGFR autophosphorylation kinetics to the L834R (also called L858R) EGFR form, one of the most common mutations in lung cancer patients. Using rapid chemical quench, time resolved electrospray mass spectrometry (ESI-MS) and western blot analyses, we examined the order of autophosphorylation in wild-type (WT) and L834R EGFR and the effect of gefitinib (Iressa ™) on the phosphorylation of individual tyrosines. These studies establish that there is a temporal order of autophosphorylation of key tyrosines involved in downstream signaling for WT EGFR and a loss of order for the oncogenic L834R mutant. These studies also reveal unique signature patterns of drug sensitivity for inhibition of tyrosine autophosphorylation by gefitinib; distinct for WT and oncogenic L834R mutant forms of EGFR. Fluorescence studies show that for WT EGFR, the binding affinity for gefitinib is weaker for the phosphorylated protein while for the oncogenic mutant, L834R EGFR, the binding affinity of gefitinib is substantially enhanced and likely contributes to the efficacy observed clinically. This mechanistic information is important in understanding the molecular details underpinning clinical observations as well as to aid in the design of more potent and selective EGFR inhibitors. PMID:22657099

Off-Target V(D)J Recombination Drives Lymphomagenesis and Is Escalated by Loss of the Rag2 C Terminus.

PubMed

Mijušković, Martina; Chou, Yi-Fan; Gigi, Vered; Lindsay, Cory R; Shestova, Olga; Lewis, Susanna M; Roth, David B

2015-09-22

Genome-wide analysis of thymic lymphomas from Tp53(-/-) mice with wild-type or C-terminally truncated Rag2 revealed numerous off-target, RAG-mediated DNA rearrangements. A significantly higher fraction of these errors mutated known and suspected oncogenes/tumor suppressor genes than did sporadic rearrangements (p < 0.0001). This tractable mouse model recapitulates recent findings in human pre-B ALL and allows comparison of wild-type and mutant RAG2. Recurrent, RAG-mediated deletions affected Notch1, Pten, Ikzf1, Jak1, Phlda1, Trat1, and Agpat9. Rag2 truncation substantially increased the frequency of off-target V(D)J recombination. The data suggest that interactions between Rag2 and a specific chromatin modification, H3K4me3, support V(D)J recombination fidelity. Oncogenic effects of off-target rearrangements created by this highly regulated recombinase may need to be considered in design of site-specific nucleases engineered for genome modification. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

MicroRNAs in thyroid development, function and tumorigenesis.

PubMed

Fuziwara, Cesar Seigi; Kimura, Edna Teruko

2017-11-15

MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression that modulate the vast majority of cellular processes. During development, the correct timing and expression of miRNAs in the tissue differentiation is essential for organogenesis and functionality. In thyroid gland, DICER and miRNAs are necessary for accurately establishing thyroid follicles and hormone synthesis. Moreover, DICER1 mutations and miRNA deregulation observed in human goiter influence thyroid tumorigenesis. The thyroid malignant transformation by MAPK oncogenes is accompanied by global miRNA changes, with a marked reduction of "tumor-suppressor" miRNAs and activation of oncogenic miRNAs. Loss of thyroid cell differentiation/function, and consequently iodine trapping impairment, is an important clinical characteristic of radioiodine-refractory thyroid cancer. However, few studies have addressed the direct role of miRNAs in thyroid gland physiology. Here, we focus on what we have learned in the thyroid follicular cell differentiation and function as revealed by cell and animal models and miRNA modulation in thyroid tumorigenesis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Oncogenic Signaling by Leukemia-Associated Mutant Cbl Proteins

PubMed Central

Nadeau, Scott; An, Wei; Palermo, Nick; Feng, Dan; Ahmad, Gulzar; Dong, Lin; Borgstahl, Gloria E. O.; Natarajan, Amarnath; Naramura, Mayumi; Band, Vimla; Band, Hamid

2013-01-01

Members of the Cbl protein family (Cbl, Cbl-b, and Cbl-c) are E3 ubiquitin ligases that have emerged as critical negative regulators of protein tyrosine kinase (PTK) signaling. This function reflects their ability to directly interact with activated PTKs and to target them as well as their associated signaling components for ubiquitination. Given the critical roles of PTK signaling in driving oncogenesis, recent studies in animal models and genetic analyses in human cancer have firmly established that Cbl proteins function as tumor suppressors. Missense mutations or small in-frame deletions within the regions of Cbl protein that are essential for its E3 activity have been identified in nearly 5% of leukemia patients with myelodysplastic/myeloproliferative disorders. Based on evidence from cell culture studies, in vivo models and clinical data, we discuss the potential signaling mechanisms of mutant Cbl-driven oncogenesis. Mechanistic insights into oncogenic Cbl mutants and associated animal models are likely to enhance our understanding of normal hematopoietic stem cell homeostasis and provide avenues for targeted therapy of mutant Cbl-driven cancers. PMID:23997989

Oncogenic NRAS, Required for Pathogenesis of Embryonic Rhabdomyosarcoma, Relies upon the HMGA2–IGF2BP2 Pathway

PubMed Central

Li, Zhizhong; Zhang, Yunyu; Ramanujan, Krishnan; Ma, Yan; Kirsch, David G.; Glass, David J.

2013-01-01

Embryonic rhabdomyosarcoma (ERMS) is the most common soft-tissue tumor in children. Here, we report the identification of the minor groove DNA-binding factor high mobility group AT-hook 2 (HMGA2) as a driver of ERMS development. HMGA2 was highly expressed in normal myoblasts and ERMS cells, where its expression was essential to maintain cell proliferation, survival in vitro, and tumor outgrowth in vivo. Mechanistic investigations revealed that upregulation of the insulin–like growth factor (IGF) mRNA-binding protein IGF2BP2 was critical for HMGA2 action. In particular, IGF2BP2 was essential for mRNA and protein stability of NRAS, a frequently mutated gene in ERMS. shRNA-mediated attenuation of NRAS or pharmacologic inhibition of the MAP-ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) effector pathway showed that NRAS and NRAS-mediated signaling was required for tumor maintenance. Taken together, these findings implicate the HMGA2–IGFBP2–NRAS signaling pathway as a critical oncogenic driver in ERMS. PMID:23536553

Dysfunctional oxidative phosphorylation makes malignant melanoma cells addicted to glycolysis driven by the (V600E)BRAF oncogene.

PubMed

Hall, Arnaldur; Meyle, Kathrine Damm; Lange, Marina Krarup; Klima, Martin; Sanderhoff, May; Dahl, Christina; Abildgaard, Cecilie; Thorup, Katrine; Moghimi, Seyed Moein; Jensen, Per Bo; Bartek, Jiri; Guldberg, Per; Christensen, Claus

2013-04-01

Oncogene addiction describes how cancer cells exhibit dependence on single oncogenes to escape apoptosis and senescence. While oncogene addiction constitutes the basis for new cancer treatment strategies targeting individual kinases and pathways activated by oncogenic mutations, the biochemical basis for this addiction is largely unknown. Here we provide evidence for a metabolic rationale behind the addiction to (V600E)BRAF in two malignant melanoma cell lines. Both cell lines display a striking addiction to glycolysis due to underlying dysfunction of oxidative phosphorylation (OXPHOS). Notably, even minor reductions in glycolytic activity lead to increased OXPHOS activity (reversed Warburg effect), however the mitochondria are unable to sustain ATP production. We show that (V600E)BRAF upholds the activity of glycolysis and therefore the addiction to glycolysis de facto becomes an addiction to (V600E)BRAF. Finally, the senescence response associated with inhibition of (V600E)BRAF is rescued by overexpression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), providing direct evidence that oncogene addiction rests on a metabolic foundation.

Analysis of alterations of oncogenes and tumor suppressor genes in chronic lymphocytic leukemia.

PubMed Central

Gaidano, G.; Newcomb, E. W.; Gong, J. Z.; Tassi, V.; Neri, A.; Cortelezzi, A.; Calori, R.; Baldini, L.; Dalla-Favera, R.

1994-01-01

B cell chronic lymphocytic leukemia (B-CLL) represents the most frequent adult leukemia in the Western world. The molecular pathogenesis of B-CLL is largely unknown. Although initial reports on small panels of cases had suggested a role for Bcl-1 and Bcl-2 oncogene activation in B-CLL, later investigations failed to confirm these data. Among tumor suppressor genes, p53 mutations have been reported in a fraction of cases. In this study, we have attempted a conclusive definition of the involvement of dominantly acting oncogenes (Bcl-1 and Bcl-2) and tumor suppressor loci (p53, 6q-) in 100 cases of B-CLL selected for their CD5 positivity and Rai's stage (0 to IV). Rearrangements of Bcl-1 and Bcl-2 and deletions of 6q and 17p were analyzed by Southern blot using multiple probes. Mutational analysis (single strand conformation polymorphism and polymerase chain reaction direct sequencing) was used to assay p53 inactivation. No alterations of Bcl-1 or Bcl-2 were detected in the 100 cases tested. Mutations of p53 were found in 10/100 cases without any significant association with clinical stage. Deletions of 6q were present in 4/100 cases. Overall, our data indicate that: 1) contrary to previous reports, Bcl-1 and Bcl-2 rearrangements are not involved in CD5+ B-CLL pathogenesis and 2) p53 mutations are present in 10% of cases at all stages of the disease. Images Figure 1 Figure 2 Figure 3 PMID:8203469

RNA splicing, cell signaling, and response to therapies.

PubMed

Abou Faycal, Cherine; Gazzeri, Sylvie; Eymin, Beatrice

2016-01-01

PremRNA alternative splicing is more a rule than an exception as it affects more than 90% of multiexons genes and plays a key role in proteome diversity. Here, we discuss some recent studies published in the extensively growing field linking RNA splicing and cancer. These last years, the development of high-throughput studies together with appropriate bioinformatic tools have led to the identification of new cancer-specific splicing patterns that allow to distinguish various cancer types, and provide new prognosis biomarkers. In addition, the functional consequences of hot spot mutations affecting various components of the spliceosome machinery in cancers have been described. As an example, missplicing of the enhancer of zeste homolog 2 histone methyltransferase premRNA in response to hot spot mutation of the splicing factor SRSF2 was found to participate to the pathogenesis of myelodysplastic syndrome. Moreover, proofs of principle that targeting the RNA splicing machinery can be used to correct aberrant missplicing, kill oncogene-driven cancer cells, or reverse resistance of tumor cells to targeted therapies have been done. As another example, the core spliceosomal function was recently found to be critical for the survival of Myc-driven breast cancer cells, rendering them hypersensitive to spliceosome inhibitors. Dysregulation of premRNA alternative splicing appears to be one of the hallmarks of cancer. The characterization of novel splicing signatures in cancer as well as the identification of original signaling networks involving RNA splicing regulators should allow to decipher novel oncogenic mechanisms and to develop new therapeutic strategies.

Amplification of Chromosome 1q Genes Encoding the Phosphoinositide Signalling Enzymes PI4KB, AKT3, PIP5K1A and PI3KC2B in Breast Cancer

PubMed Central

Waugh, Mark G.

2014-01-01

Little is known about the possible oncogenic roles of genes encoding for the phosphatidylinositol 4-kinases, a family of enzymes that regulate an early step in phosphoinositide signalling. To address this issue, the mutational status of all four human phosphatidylinositol 4-kinases genes was analyzed across 852 breast cancer samples using the COSMIC data resource. Point mutations in the phosphatidylinositol 4-kinase genes were uncommon and appeared in less than 1% of the patient samples however, 62% of the tumours had increases in gene copy number for PI4KB which encodes the phosphatidylinositol 4-kinase IIIbeta isozyme. Extending this analysis to subsequent enzymes in the phosphoinositide signalling cascades revealed that the only PIP5K1A, PI3KC2B and AKT3 genes exhibited similar patterns of gene copy number variation. By comparison, gene copy number increases for established oncogenes such as EGFR and HER2/Neu were only evident in 20% of the samples. The PI4KB, PIP5K1A, PI3KC2B and AKT3 genes are related in that they all localize to chromosome 1q which is often structurally and numerically abnormal in breast cancer. These results demonstrate that a gene quartet encoding a potential phosphoinositide signalling pathway is amplified in a subset of breast cancers. PMID:25368680

Increased phosphorylation of ERK1/2 is associated with worse chemotherapeutic outcome and a poor prognosis in advanced lung adenocarcinoma.

PubMed

Tsujino, Ichiro; Nakanishi, Yoko; Hiranuma, Hisato; Shimizu, Tetsuo; Hirotani, Yukari; Ohni, Sumie; Ouchi, Yasushi; Takahashi, Noriaki; Nemoto, Norimichi; Hashimoto, Shu

2016-06-01

Constitutive activation of extracellular signal-regulated kinase (ERK)1/2 pathway, that is activated by various stimuli including growth factors and oncogenic driver mutations, is observed in various cancers. However, the difference of the activated levels of the pathway is still unclear in clinical significances. The aim of this study was to investigate the effect of different ERK1/2 pathway activation, assessed by the expression levels of phosphorylated (p) ERK1/2, on the prognosis of advanced lung adenocarcinoma patients. Paraffin-embedded lung biopsy samples were obtained from 85 lung adenocarcinoma patients. Correlation between pERK1/2 expression levels that were assessed by immunohistochemistry (IHC) analysis and oncogenic driver mutation status, clinicopathological factors, outcome from standard anticancer therapies, and prognosis was investigated. Varying levels of pERK1/2 expression were observed in 68 (80.0 %) patients. The overall survival was significantly reduced in patients with higher pERK1/2 expression in comparison to those with lower expression levels (P = 0.03). In particular, higher pERK1/2 expression levels correlated with worse performance status and worse clinical outcome. Thus, the IHC analysis of pERK1/2 expression levels may predict patient prognosis in advanced lung adenocarcinoma. Inhibition of ERK1/2 pathway activated by various signals may improve the effects of standard chemotherapies and the clinical condition of patients with advanced cancer.

Oncogenes Activate an Autonomous Transcriptional Regulatory Circuit That Drives Glioblastoma.

PubMed

Singh, Dinesh K; Kollipara, Rahul K; Vemireddy, Vamsidara; Yang, Xiao-Li; Sun, Yuxiao; Regmi, Nanda; Klingler, Stefan; Hatanpaa, Kimmo J; Raisanen, Jack; Cho, Steve K; Sirasanagandla, Shyam; Nannepaga, Suraj; Piccirillo, Sara; Mashimo, Tomoyuki; Wang, Shan; Humphries, Caroline G; Mickey, Bruce; Maher, Elizabeth A; Zheng, Hongwu; Kim, Ryung S; Kittler, Ralf; Bachoo, Robert M

2017-01-24

Efforts to identify and target glioblastoma (GBM) drivers have primarily focused on receptor tyrosine kinases (RTKs). Clinical benefits, however, have been elusive. Here, we identify an SRY-related box 2 (SOX2) transcriptional regulatory network that is independent of upstream RTKs and capable of driving glioma-initiating cells. We identified oligodendrocyte lineage transcription factor 2 (OLIG2) and zinc-finger E-box binding homeobox 1 (ZEB1), which are frequently co-expressed irrespective of driver mutations, as potential SOX2 targets. In murine glioma models, we show that different combinations of tumor suppressor and oncogene mutations can activate Sox2, Olig2, and Zeb1 expression. We demonstrate that ectopic co-expression of the three transcription factors can transform tumor-suppressor-deficient astrocytes into glioma-initiating cells in the absence of an upstream RTK oncogene. Finally, we demonstrate that the transcriptional inhibitor mithramycin downregulates SOX2 and its target genes, resulting in markedly reduced proliferation of GBM cells in vivo. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Nanoproteomic analysis of extracellular receptor kinase-1/2 post-translational activation in microdissected human hyperplastic colon lesions.

PubMed

Drew, David A; Devers, Thomas; Horelik, Nicole; Yang, Shi; O'Brien, Michael; Wu, Rong; Rosenberg, Daniel W

2013-05-01

Oncogenic activation resulting in hyperproliferative lesions within the colonic mucosa has been identified in putative precancerous lesions, aberrant crypt foci (ACF). KRAS and BRAF mutation status was determined in 172 ACF identified in the colorectum of screening subjects by in situ high-definition, magnifying chromoendoscopy. Lesions were stratified according to histology (serrated vs. distended). Due to their limiting size, however, it was not technically feasible to examine downstream signaling consequences of these oncogenic mutations. We have combined ultraviolet-infrared (UV/IR) microdissection with an ultrasensitive nanofluidic proteomic immunoassay (NIA) to enable accurate quantification of posttranslational modifications to mitogen-activated protein kinase (MAPK) in total protein lysates isolated from hyperproliferative crypts and adjacent normal mucosa. Using this approach, levels of singly and dually (activated) phosphorylated isoforms of extracellular receptor kinase(ERK)-1 and ERK-2 were quantified in samples containing as little as 16 ng of total protein recovered from <200 cells. ERK activation is responsible for observed hyperplasia found in these early lesions, but is not directly dependent on KRAS and/or BRAF mutation status. This study describes the novel use of a sensitive nanofluidic platform to measure oncogene-driven proteomic changes in diminutive lesions and highlights the advantage of this approach over classical immunohistochemistry-based analyses. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

RET is a potential tumor suppressor gene in colorectal cancer

PubMed Central

Luo, Yanxin; Tsuchiya, Karen D.; Park, Dong Il; Fausel, Rebecca; Kanngurn, Samornmas; Welcsh, Piri; Dzieciatkowski, Slavomir; Wang, Jianping; Grady, William M.

2012-01-01

Cancer arises as the consequence of mutations and epigenetic alterations that activate oncogenes and inactivate tumor suppressor genes. Through a genome-wide screen for methylated genes in colon neoplasms, we identified aberrantly methylated RET in colorectal cancer. RET, a transmembrane receptor tyrosine kinase and a receptor for the GDNF-family ligands, was one of the first oncogenes to be identified and has been shown to be an oncogene in thyroid cancer and pheochromocytoma. However, unexpectedly, we found RET is methylated in 27% of colon adenomas and in 63% of colorectal cancers, and now provide evidence that RET has tumor suppressor activity in colon cancer. The aberrant methylation of RET correlates with decreased RET expression, whereas the restoration of RET in colorectal cancer cell lines results in apoptosis. Furthermore, in support of a tumor suppressor function of RET, mutant RET has also been found in primary colorectal cancer. We now show that these mutations inactivate RET, which is consistent with RET being a tumor suppressor gene in the colon. These findings suggest that the aberrant methylation of RET and the mutational inactivation of RET promote colorectal cancer formation and that RET can serve as a tumor suppressor gene in the colon. Moreover, the increased frequency of methylated RET in colon cancers compared to adenomas suggests RET inactivation is involved in the progression of colon adenomas to cancer. PMID:22751117

Mutations within ICP4 acquired during in vitro attenuation do not alter virulence of recombinant Marek’s disease viruses in vivo

USDA-ARS?s Scientific Manuscript database

Marek's disease (MD) is a T-cell lymphoma of chickens caused by the oncogenic Marek's disease virus (MDV). MD is primarily controlled by live-attenuated vaccines generated by repeated in vitro serial passage. Previous efforts to characterize attenuated MDVs identified numerous mutations, particularl...

IDH mutations in liver cell plasticity and biliary cancer

PubMed Central

Saha, Supriya K; Parachoniak, Christine A; Bardeesy, Nabeel

2014-01-01

Intrahepatic cholangiocarcinoma (ICC) is an aggressive cancer associated with the bile ducts within the liver. These tumors are characterized by frequent gain-of-function mutations in the isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) genes—that are also common in subsets of neural, haematopoietic and bone tumors, but rare or absent in the other types of gastrointestinal malignancy. Mutant IDH acts through a novel mechanism of oncogenesis, producing high levels of the metabolite 2-hydroxyglutarate, which interferes with the function of α-ketoglutarate-dependent enzymes that regulate diverse cellular processes including histone demethylation and DNA modification. Recently, we used in vitro stem cell systems and genetically engineered mouse models (GEMMs) to demonstrate that mutant IDH promotes ICC formation by blocking hepatocyte differentiation and increasing pools of hepatic progenitors that are susceptible to additional oncogenic hits leading to ICC. We found that silencing of HNF4A—encoding a master transcriptional regulator of hepatocyte identity and quiescence—was critical to mutant IDH-mediated inhibition of liver differentiation. In line with these findings, human ICC with IDH mutations are characterized by a hepatic progenitor cell transcriptional signature suggesting that they are a distinct ICC subtype as compared to IDH wild type tumors. The role of mutant IDH in controlling hepatic differentiation state suggests the potential of newly developed inhibitors of the mutant enzyme as a form of differentiation therapy in a solid tumor. PMID:25485496

Pan-cancer transcriptomic analysis associates long non-coding RNAs with key mutational driver events

PubMed Central

Ashouri, Arghavan; Sayin, Volkan I.; Van den Eynden, Jimmy; Singh, Simranjit X.; Papagiannakopoulos, Thales; Larsson, Erik

2016-01-01

Thousands of long non-coding RNAs (lncRNAs) lie interspersed with coding genes across the genome, and a small subset has been implicated as downstream effectors in oncogenic pathways. Here we make use of transcriptome and exome sequencing data from thousands of tumours across 19 cancer types, to identify lncRNAs that are induced or repressed in relation to somatic mutations in key oncogenic driver genes. Our screen confirms known coding and non-coding effectors and also associates many new lncRNAs to relevant pathways. The associations are often highly reproducible across cancer types, and while many lncRNAs are co-expressed with their protein-coding hosts or neighbours, some are intergenic and independent. We highlight lncRNAs with possible functions downstream of the tumour suppressor TP53 and the master antioxidant transcription factor NFE2L2. Our study provides a comprehensive overview of lncRNA transcriptional alterations in relation to key driver mutational events in human cancers. PMID:28959951

BRAF V600E mutations in papillary craniopharyngioma

PubMed Central

Brastianos, Priscilla K.; Santagata, Sandro

2016-01-01

Papillary craniopharyngioma is an intracranial tumor that results in high levels of morbidity. We recently demonstrated that the vast majority of these tumors harbor the oncogenic BRAF V600E mutation. The pathologic diagnosis of papillary craniopharyngioma can now be confirmed using mutation specific immunohistochemistry and targeted genetic testing. Treatment with targeted agents is now also a possibility in select situations. We recently reported a patient with a multiply recurrent papillary craniopharyngioma in whom targeting both BRAF and MEK resulted in a dramatic therapeutic response with a marked anti-tumor immune response. This work shows that activation of the MAPK pathway is the likely principal oncogenic driver of these tumors. We will now investigate the efficacy of this approach in a multicenter phase II clinical trial. Post-treatment resection samples will be monitored for the emergence of resistance mechanisms. Further advances in the non-invasive diagnosis of papillary craniopharyngioma by radiologic criteria and by cell-free DNA testing could someday allow neo-adjuvant therapy for this disease in select patient populations. PMID:26563980

Neutral competition of stem cells is skewed by proliferative changes downstream of Hh and Hpo.

PubMed

Amoyel, Marc; Simons, Benjamin D; Bach, Erika A

2014-10-16

Neutral competition, an emerging feature of stem cell homeostasis, posits that individual stem cells can be lost and replaced by their neighbors stochastically, resulting in chance dominance of a clone at the niche. A single stem cell with an oncogenic mutation could bias this process and clonally spread the mutation throughout the stem cell pool. The Drosophila testis provides an ideal system for testing this model. The niche supports two stem cell populations that compete for niche occupancy. Here, we show that cyst stem cells (CySCs) conform to the paradigm of neutral competition and that clonal deregulation of either the Hedgehog (Hh) or Hippo (Hpo) pathway allows a single CySC to colonize the niche. We find that the driving force behind such behavior is accelerated proliferation. Our results demonstrate that a single stem cell colonizes its niche through oncogenic mutation by co-opting an underlying homeostatic process. © 2014 The Authors.

Genomic catastrophes frequently arise in esophageal adenocarcinoma and drive tumorigenesis

PubMed Central

Patch, Ann-Marie; Bailey, Peter; Newell, Felicity; Holmes, Oliver; Fink, J. Lynn; Quinn, Michael C.J.; Tang, Yue Hang; Lampe, Guy; Quek, Kelly; Loffler, Kelly A.; Manning, Suzanne; Idrisoglu, Senel; Miller, David; Xu, Qinying; Waddell, Nick; Wilson, Peter J.; Bruxner, Timothy J.C.; Christ, Angelika N.; Harliwong, Ivon; Nourse, Craig; Nourbakhsh, Ehsan; Anderson, Matthew; Kazakoff, Stephen; Leonard, Conrad; Wood, Scott; Simpson, Peter T.; Reid, Lynne E.; Krause, Lutz; Hussey, Damian J.; Watson, David I.; Lord, Reginald V.; Nancarrow, Derek; Phillips, Wayne A.; Gotley, David; Smithers, B. Mark; Whiteman, David C.; Hayward, Nicholas K.; Campbell, Peter J.; Pearson, John V.; Grimmond, Sean M.; Barbour, Andrew P.

2015-01-01

Oesophageal adenocarcinoma (EAC) incidence is rapidly increasing in Western countries. A better understanding of EAC underpins efforts to improve early detection and treatment outcomes. While large EAC exome sequencing efforts to date have found recurrent loss-of-function mutations, oncogenic driving events have been underrepresented. Here we use a combination of whole-genome sequencing (WGS) and single-nucleotide polymorphism-array profiling to show that genomic catastrophes are frequent in EAC, with almost a third (32%, n = 40/123) undergoing chromothriptic events. WGS of 22 EAC cases show that catastrophes may lead to oncogene amplification through chromothripsis-derived double-minute chromosome formation (MYC and MDM2) or breakage-fusion-bridge (KRAS, MDM2 and RFC3). Telomere shortening is more prominent in EACs bearing localized complex rearrangements. Mutational signature analysis also confirms that extreme genomic instability in EAC can be driven by somatic BRCA2 mutations. These findings suggest that genomic catastrophes have a significant role in the malignant transformation of EAC. PMID:25351503

Targeted Therapies in Non-Small Cell Lung Cancer-Beyond EGFR and ALK.

PubMed

Rothschild, Sacha I

2015-05-26

Systemic therapy for non-small cell lung cancer (NSCLC) has undergone a dramatic paradigm shift over the past decade. Advances in our understanding of the underlying biology of NSCLC have revealed distinct molecular subtypes. A substantial proportion of NSCLC depends on oncogenic molecular aberrations (so-called "driver mutations") for their malignant phenotype. Personalized therapy encompasses the strategy of matching these subtypes with effective targeted therapies. EGFR mutations and ALK translocation are the most effectively targeted oncogenes in NSCLC. EGFR mutations and ALK gene rearrangements are successfully being targeted with specific tyrosine kinase inhibitors. The number of molecular subgroups of NSCLC continues to grow. The scope of this review is to discuss recent data on novel molecular targets as ROS1, BRAF, KRAS, HER2, c-MET, RET, PIK3CA, FGFR1 and DDR2. Thereby the review will focus on therapeutic strategies targeting these aberrations. Moreover, the emerging challenge of acquired resistance to initially effective therapies will be discussed.

Comparison of EGFR signaling pathway somatic DNA mutations derived from peripheral blood and corresponding tumor tissue of patients with advanced non-small-cell lung cancer using liquidchip technology.

PubMed

Zhang, Hui; Liu, Deruo; Li, Shanqing; Zheng, Yongqing; Yang, Xinjie; Li, Xi; Zhang, Quan; Qin, Na; Lu, Jialin; Ren-Heidenreich, Lifen; Yang, Huiyi; Wu, Yuhua; Zhang, Xinyong; Nong, Jingying; Sun, Yifen; Zhang, Shucai

2013-11-01

Somatic DNA mutations affecting the epidermal growth factor receptor (EGFR) signaling pathway are known to predict responsiveness to EGFR-tyrosine kinase inhibitor drugs in patients with advanced non-small-cell lung cancers. We evaluated a sensitive liquidchip platform for detecting EGFR, KRAS (alias Ki-ras), proto-oncogene B-Raf, and phosphatidylinositol 3-kinase CA mutations in plasma samples, which were highly correlated with matched tumor tissues from 86 patients with advanced non-small-cell lung cancers. Either EGFR exon 19 or 21 mutations were detected in 36 patients: 23 of whom had identical mutations in both their blood and tissue samples; whereas mutations in the remaining 13 were found only in their tumor samples. These EGFR mutations occurred at a significantly higher frequency in females, never-smokers, and in patients with adenocarcinomas (P ≤ 0.001). The EGFR exon 20 T790M mutation was detected in only one of the paired samples [100% (95% CI, 96% to 100%) agreement]. For KRAS, proto-oncogene B-Raf, and phosphatidylinositol 3-kinase CA mutations, the overall agreements were 97% (95% CI, 90% to 99%), 98% (95% CI, 92% to 99%), and 97% (95% CI, 90% to 99%), respectively, and these were not associated with age, sex, smoking history, or histopathologic type. In conclusion, mutations detected in plasma correlated strongly with mutation profiles in each respective tumor sample, suggesting that this liquidchip platform may offer a rapid and noninvasive method for predicting tumor responsiveness to EGFR-tyrosine kinase inhibitor drugs in patients with advanced non-small-cell lung cancers. Copyright © 2013 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

PEST domain mutations in Notch receptors comprise an oncogenic driver segment in triple-negative breast cancer sensitive to a γ-secretase inhibitor.

PubMed

Wang, Kai; Zhang, Qin; Li, Danan; Ching, Keith; Zhang, Cathy; Zheng, Xianxian; Ozeck, Mark; Shi, Stephanie; Li, Xiaorong; Wang, Hui; Rejto, Paul; Christensen, James; Olson, Peter

2015-03-15

To identify and characterize novel, activating mutations in Notch receptors in breast cancer and to determine response to the gamma secretase inhibitor (GSI) PF-03084014. We used several computational approaches, including novel algorithms, to analyze next-generation sequencing data and related omic datasets from The Cancer Genome Atlas (TCGA) breast cancer cohort. Patient-derived xenograft (PDX) models were sequenced, and Notch-mutant models were treated with PF-03084014. Gene-expression and functional analyses were performed to study the mechanism of activation through mutation and inhibition by PF-03084014. We identified mutations within and upstream of the PEST domains of NOTCH1, NOTCH2, and NOTCH3 in the TCGA dataset. Mutations occurred via several genetic mechanisms and compromised the function of the PEST domain, a negative regulatory domain commonly mutated in other cancers. Focal amplifications of NOTCH2 and NOTCH3 were also observed, as were heterodimerization or extracellular domain mutations at lower incidence. Mutations and amplifications often activated the Notch pathway as evidenced by increased expression of canonical Notch target genes, and functional mutations were significantly enriched in the triple-negative breast cancer subtype (TNBC). PDX models were also identified that harbored PEST domain mutations, and these models were highly sensitive to PF-03084014. This work suggests that Notch-altered breast cancer constitutes a bona fide oncogenic driver segment with the most common alteration being PEST domain mutations present in multiple Notch receptors. Importantly, functional studies suggest that this newly identified class can be targeted with Notch inhibitors, including GSIs. ©2015 American Association for Cancer Research.

Multi-institutional oncogenic driver mutation analysis in lung adenocarcinoma: The Lung Cancer Mutation Consortium experience

PubMed Central

Dias-Santagata, Dora; Wistuba, Ignacio I.; Chen, Heidi; Fujimoto, Junya; Kugler, Kelly; Franklin, Wilbur A.; Iafrate, A. John; Ladanyi, Marc; Kris, Mark G.; Johnson, Bruce E.; Bunn, Paul A.; Minna, John D.; Kwiatkowski, David J.

2015-01-01

Introduction Molecular genetic analyses of lung adenocarcinoma have recently become standard of care for treatment selection. The Lung Cancer Mutation Consortium was formed to enable collaborative multi-institutional analyses of 10 potential oncogenic driver mutations. Technical aspects of testing, and clinicopathologic correlations are presented. Methods Mutation testing in at least one of 8 genes (EGFR, KRAS, ERBB2, AKT1, BRAF, MEK1, NRAS, PIK3CA) using SNaPshot, mass spectrometry, Sanger sequencing +/− PNA and/or sizing assays, along with ALK and/or MET FISH were performed in 6 labs on 1007 patients from 14 institutions. Results 1007 specimens had mutation analysis performed, and 733 specimens had all 10 genes analyzed. Mutation identification rates did not vary by analytic method. Biopsy and cytology specimens were inadequate for testing in 26% and 35% of cases compared to 5% of surgical specimens. Among the 1007 cases with mutation analysis performed, EGFR, KRAS, ALK, and ERBB2 alterations were detected in 22, 25, 8.5, and 2.4% of cases, respectively. EGFR mutations were highly associated with female sex, Asian race, and never smoking status; and less strongly associated with stage IV disease, presence of bone metastases, and absence of adrenal metastases. ALK rearrangements were strongly associated with never smoking status, and more weakly associated with presence of liver metastases. ERBB2 mutations were strongly associated with Asian race and never smoking status. Two mutations were seen in 2.7% of samples, all but one of which involved one or more of PIK3CA, ALK or MET. Conclusion Multi-institutional molecular analysis across multiple platforms, sample types, and institutions can yield consistent results and novel clinicopathological observations. PMID:25738220

Molecular alterations of EGFR and PIK3CA in uterine serous carcinoma.

PubMed

Hayes, Monica Prasad; Douglas, Wayne; Ellenson, Lora Hedrick

2009-06-01

Uterine serous carcinoma (USC) is an aggressive endometrial cancer associated with poor prognosis despite comprehensive surgical staging and adjuvant chemotherapy and radiation therapy. Biologic targets have yet to be fully explored in this disease and research on such targets could lead to clinical trials utilizing a new class of therapeutics. This study sought to evaluate primary USC tumors for molecular alterations in epidermal growth factor receptor (EGFR) and the recently characterized oncogene PIK3CA, which encodes the catalytic p110-alpha subunit of phosphatidylinositol 3-kinase (PI3K) and thus activates the AKT-mTOR oncogenic pathway. Paraffin-embedded archival tissue of 45 primary USC tumors was utilized in this study. Immunohistochemical analysis of EGFR was performed and cases given a score of 0 to 12 calculated as the product of staining intensity (0 to 3+) and the percentage of positively stained cells (0-4), with 1=1-25%, 2=26-50%, 3=51-75%, and 4=76-100%. For mutational analysis, neoplastic tissue was microdissected and DNA was extracted with phenol-chloroform. Exons 18 through 21 of EGFR and exons 9 and 20 of PIK3CA, the most commonly mutated exons of these genes, were amplified and directly sequenced. When EGFR was evaluated, moderate or strong EGFR membranous staining was observed in 25/45 (56%) USC cases. Thus, a mutational analysis was performed on 35 cases, including all cases with moderate and strong EGFR staining. No mutations were identified in EGFR. In contrast, PIK3CA mutations were confirmed in 5/34 (15%) of USC cases. Four cases were mutated in exon 20 and one case was mutated in exon 9. Since optimal treatment of uterine serous carcinoma remains unknown, novel therapeutic approaches need to be actively pursued. In the current study of primary USC tumors, oncogenic mutations of the PIK3CA gene were seen in 15% of USC cases. This represents the first report of this gene mutation in USC. In addition, EGFR stained positively in the majority of cases, suggesting a possible target protein. These findings warrant further investigation and suggest a potential role for therapeutic agents targeting the PI3K-AKT-mTOR pathway, such as rapamycin, as well as possible targets of EGFR in the treatment of uterine serous carcinoma.

Shuttling imbalance of MLF1 results in p53 instability and increases susceptibility to oncogenic transformation.

PubMed

Yoneda-Kato, Noriko; Kato, Jun-Ya

2008-01-01

Myeloid leukemia factor 1 (MLF1) stabilizes the activity of the tumor suppressor p53 by suppressing its E3 ubiquitin ligase, COP1, through a third component of the COP9 signalosome (CSN3). However, little is known about how MLF1 functions upstream of the CSN3-COP1-p53 pathway and how its deregulation by the formation of the fusion protein nucleophosmin (NPM)-MLF1, generated by t(3;5)(q25.1;q34) chromosomal translocation, leads to leukemogenesis. Here we show that MLF1 is a cytoplasmic-nuclear-shuttling protein and that its nucleolar localization on fusing with NPM prevents the full induction of p53 by both genotoxic and oncogenic cellular stress. The majority of MLF1 was located in the cytoplasm, but the treatment of cells with leptomycin B rapidly induced a nuclear accumulation of MLF1. A mutation of the nuclear export signal (NES) motif identified in the MLF1 sequence enhanced the antiproliferative activity of MLF1. The fusion of MLF1 with NPM translocated MLF1 to the nucleolus and abolished the growth-suppressing activity. The introduction of NPM-MLF1 into early-passage murine embryonic fibroblasts allowed the cells to escape from cellular senescence at a markedly earlier stage and induced neoplastic transformation in collaboration with the oncogenic form of Ras. Interestingly, disruption of the MLF1-derived NES sequence completely abolished the growth-promoting activity of NPM-MLF1 in murine fibroblasts and hematopoietic cells. Thus, our results provide important evidence that the shuttling of MLF1 is critical for the regulation of cell proliferation and a disturbance in the shuttling balance increases the cell's susceptibility to oncogenic transformation.

Shuttling Imbalance of MLF1 Results in p53 Instability and Increases Susceptibility to Oncogenic Transformation▿ †

PubMed Central

Yoneda-Kato, Noriko; Kato, Jun-ya

2008-01-01

Myeloid leukemia factor 1 (MLF1) stabilizes the activity of the tumor suppressor p53 by suppressing its E3 ubiquitin ligase, COP1, through a third component of the COP9 signalosome (CSN3). However, little is known about how MLF1 functions upstream of the CSN3-COP1-p53 pathway and how its deregulation by the formation of the fusion protein nucleophosmin (NPM)-MLF1, generated by t(3;5)(q25.1;q34) chromosomal translocation, leads to leukemogenesis. Here we show that MLF1 is a cytoplasmic-nuclear-shuttling protein and that its nucleolar localization on fusing with NPM prevents the full induction of p53 by both genotoxic and oncogenic cellular stress. The majority of MLF1 was located in the cytoplasm, but the treatment of cells with leptomycin B rapidly induced a nuclear accumulation of MLF1. A mutation of the nuclear export signal (NES) motif identified in the MLF1 sequence enhanced the antiproliferative activity of MLF1. The fusion of MLF1 with NPM translocated MLF1 to the nucleolus and abolished the growth-suppressing activity. The introduction of NPM-MLF1 into early-passage murine embryonic fibroblasts allowed the cells to escape from cellular senescence at a markedly earlier stage and induced neoplastic transformation in collaboration with the oncogenic form of Ras. Interestingly, disruption of the MLF1-derived NES sequence completely abolished the growth-promoting activity of NPM-MLF1 in murine fibroblasts and hematopoietic cells. Thus, our results provide important evidence that the shuttling of MLF1 is critical for the regulation of cell proliferation and a disturbance in the shuttling balance increases the cell's susceptibility to oncogenic transformation. PMID:17967869

In vitro modeling of human pancreatic duct epithelial cell transformation defines gene expression changes induced by K-ras oncogenic activation in pancreatic carcinogenesis.

PubMed

Qian, Jiaying; Niu, Jiangong; Li, Ming; Chiao, Paul J; Tsao, Ming-Sound

2005-06-15

Genetic analysis of pancreatic ductal adenocarcinomas and their putative precursor lesions, pancreatic intraepithelial neoplasias (PanIN), has shown a multistep molecular paradigm for duct cell carcinogenesis. Mutational activation or inactivation of the K-ras, p16(INK4A), Smad4, and p53 genes occur at progressive and high frequencies in these lesions. Oncogenic activation of the K-ras gene occurs in >90% of pancreatic ductal carcinoma and is found early in the PanIN-carcinoma sequence, but its functional roles remain poorly understood. We show here that the expression of K-ras(G12V) oncogene in a near diploid HPV16-E6E7 gene immortalized human pancreatic duct epithelial cell line originally derived from normal pancreas induced the formation of carcinoma in 50% of severe combined immunodeficient mice implanted with these cells. A tumor cell line established from one of these tumors formed ductal cancer when implanted orthotopically. These cells also showed increased activation of the mitogen-activated protein kinase, AKT, and nuclear factor-kappaB pathways. Microarray expression profiling studies identified 584 genes whose expression seemed specifically up-regulated by the K-ras oncogene expression. Forty-two of these genes have been reported previously as differentially overexpressed in pancreatic cancer cell lines or primary tumors. Real-time PCR confirmed the overexpression of a large number of these genes. Immunohistochemistry done on tissue microarrays constructed from PanIN and pancreatic cancer samples showed laminin beta3 overexpression starting in high-grade PanINs and occurring in >90% of pancreatic ductal carcinoma. The in vitro modeling of human pancreatic duct epithelial cell transformation may provide mechanistic insights on gene expression changes that occur during multistage pancreatic duct cell carcinogenesis.

Oncogenic JAK2V617F requires an intact SH2-like domain for constitutive activation and induction of a myeloproliferative disease in mice.

PubMed

Gorantla, Sivahari P; Dechow, Tobias N; Grundler, Rebekka; Illert, Anna Lena; Zum Büschenfelde, Christian Meyer; Kremer, Marcus; Peschel, Christian; Duyster, Justus

2010-11-25

The oncogenic JAK2V617F mutation is found in myeloproliferative neoplasms (MPNs) and is believed to be critical for leukemogenesis. Here we show that JAK2V617F requires an intact SH2 domain for constitutive activation of downstream signaling pathways. In addition, there is a strict requirement of cytokine receptor expression for the activation of this oncogene. Further analysis showed that the SH2 domain mutation did not interfere with JAK2 membrane distribution. However, coimmunoprecipitated experiments revealed a role for the SH2 domain in the aggregation and cross-phosphorylation of JAK2V617F at the cell membrane. Forced overexpression of cytokine receptors could rescue the JAK2V617F SH2 mutant supporting a critical role of JAK2V617F abundance for constitutive activation. However, under physiologic cytokine receptor expression the SH2 domain is absolutely necessary for oncogenic JAK2V617F activation. This is demonstrated in a bone marrow transplantation model, in which an intact SH2 domain in JAK2V617F is required for the induction of an MPN-like disease. Thus, our results points to an indispensable role of the SH2 domain in JAK2V617F-induced MPNs.

Links between metabolism and cancer

PubMed Central

Dang, Chi V.

2012-01-01

Metabolism generates oxygen radicals, which contribute to oncogenic mutations. Activated oncogenes and loss of tumor suppressors in turn alter metabolism and induce aerobic glycolysis. Aerobic glycolysis or the Warburg effect links the high rate of glucose fermentation to cancer. Together with glutamine, glucose via glycolysis provides the carbon skeletons, NADPH, and ATP to build new cancer cells, which persist in hypoxia that in turn rewires metabolic pathways for cell growth and survival. Excessive caloric intake is associated with an increased risk for cancers, while caloric restriction is protective, perhaps through clearance of mitochondria or mitophagy, thereby reducing oxidative stress. Hence, the links between metabolism and cancer are multifaceted, spanning from the low incidence of cancer in large mammals with low specific metabolic rates to altered cancer cell metabolism resulting from mutated enzymes or cancer genes. PMID:22549953

Role of Non Receptor Tyrosine Kinases in Hematological Malignances and its Targeting by Natural Products.

PubMed

Siveen, Kodappully S; Prabhu, Kirti S; Achkar, Iman W; Kuttikrishnan, Shilpa; Shyam, Sunitha; Khan, Abdul Q; Merhi, Maysaloun; Dermime, Said; Uddin, Shahab

2018-02-19

Tyrosine kinases belong to a family of enzymes that mediate the movement of the phosphate group to tyrosine residues of target protein, thus transmitting signals from the cell surface to cytoplasmic proteins and the nucleus to regulate physiological processes. Non-receptor tyrosine kinases (NRTK) are a sub-group of tyrosine kinases, which can relay intracellular signals originating from extracellular receptor. NRTKs can regulate a huge array of cellular functions such as cell survival, division/propagation and adhesion, gene expression, immune response, etc. NRTKs exhibit considerable variability in their structural make up, having a shared kinase domain and commonly possessing many other domains such as SH2, SH3 which are protein-protein interacting domains. Recent studies show that NRTKs are mutated in several hematological malignancies, including lymphomas, leukemias and myelomas, leading to aberrant activation. It can be due to point mutations which are intragenic changes or by fusion of genes leading to chromosome translocation. Mutations that lead to constitutive kinase activity result in the formation of oncogenes, such as Abl, Fes, Src, etc. Therefore, specific kinase inhibitors have been sought after to target mutated kinases. A number of compounds have since been discovered, which have shown to inhibit the activity of NRTKs, which are remarkably well tolerated. This review covers the role of various NRTKs in the development of hematological cancers, including their deregulation, genetic alterations, aberrant activation and associated mutations. In addition, it also looks at the recent advances in the development of novel natural compounds that can target NRTKs and perhaps in combination with other forms of therapy can show great promise for the treatment of hematological malignancies.

Regulation of pokemon 1 activity by sumoylation.

PubMed

Roh, Hee-Eun; Lee, Min-Nyung; Jeon, Bu-Nam; Choi, Won-Il; Kim, Yoo-Jin; Yu, Mi-Young; Hur, Man-Wook

2007-01-01

Pokemon 1 is a proto-oncogenic transcriptional regulator that contains a POZ domain at the N-terminus and four Kruppel-like zinc fingers at the C-terminus. Pokemon 1 plays an important role in adipogenesis, osteogenesis, oncogenesis, and transcription of NF-kB responsive genes. Recent reports have shown that biological activities of transcription factors are regulated by sumolylation. We investigated whether Pokemon 1 is post-translationally modified by sumoylation and whether the modification affects Pokemon 1's transcriptional properties. We found that Pokemon 1 is sumoylated in vitro and in vivo. Upon careful analysis of the amino acid sequence of Pokemon 1, we found ten potential sumoylation sites located at lysines 61, 354, 371, 379, 383, 396, 486, 487, 536 and 539. We mutated each of these amino acids into arginine and tested whether the mutation could affect the transcriptional properties of Pokemon 1 on the Pokemon 1 responsive genes, such as ADH5/FDH and pG5-FRE-Luc. Wild-type Pokemon 1 potently represses transcription of ADH5/FDH. Most of the mutants, however, were weaker transcription repressors and repressed transcription 1.3-3.3 fold less effective. Although potential sumoylation sites were located close to the DNA binding domain or the nuclear localization sequence, the mutations did not alter nuclear localization or DNA binding activity. In addition, on the pG5-FRE-Luc test promoter construct, ectopic SUMO-1 repressed transcription in the presence of Pokemon 1. The sumoylation target lysine residue at amino acid 61, which is located in the middle of the POZ-domain, is important because K61R mutation resulted in a much weaker molecular interaction with corepressors. Our data suggest that Pokemon 1's activity as a transcription factor may involve sumoylation, and that sumoylation might be important in the regulation of transcription by Pokemon 1.

Signaling through the Phosphatidylinositol 3-Kinase (PI3K)/Mammalian Target of Rapamycin (mTOR) Axis Is Responsible for Aerobic Glycolysis mediated by Glucose Transporter in Epidermal Growth Factor Receptor (EGFR)-mutated Lung Adenocarcinoma.

PubMed

Makinoshima, Hideki; Takita, Masahiro; Saruwatari, Koichi; Umemura, Shigeki; Obata, Yuuki; Ishii, Genichiro; Matsumoto, Shingo; Sugiyama, Eri; Ochiai, Atsushi; Abe, Ryo; Goto, Koichi; Esumi, Hiroyasu; Tsuchihara, Katsuya

2015-07-10

Oncogenic epidermal growth factor receptor (EGFR) signaling plays an important role in regulating global metabolic pathways, including aerobic glycolysis, the pentose phosphate pathway (PPP), and pyrimidine biosynthesis. However, the molecular mechanism by which EGFR signaling regulates cancer cell metabolism is still unclear. To elucidate how EGFR signaling is linked to metabolic activity, we investigated the involvement of the RAS/MEK/ERK and PI3K/AKT/mammalian target of rapamycin (mTOR) pathways on metabolic alteration in lung adenocarcinoma (LAD) cell lines with activating EGFR mutations. Although MEK inhibition did not alter lactate production and the extracellular acidification rate, PI3K/mTOR inhibitors significantly suppressed glycolysis in EGFR-mutant LAD cells. Moreover, a comprehensive metabolomics analysis revealed that the levels of glucose 6-phosphate and 6-phosphogluconate as early metabolites in glycolysis and PPP were decreased after inhibition of the PI3K/AKT/mTOR pathway, suggesting a link between PI3K signaling and the proper function of glucose transporters or hexokinases in glycolysis. Indeed, PI3K/mTOR inhibition effectively suppressed membrane localization of facilitative glucose transporter 1 (GLUT1), which, instead, accumulated in the cytoplasm. Finally, aerobic glycolysis and cell proliferation were down-regulated when GLUT1 gene expression was suppressed by RNAi. Taken together, these results suggest that PI3K/AKT/mTOR signaling is indispensable for the regulation of aerobic glycolysis in EGFR-mutated LAD cells. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Mutational landscape, clonal evolution patterns, and role of RAS mutations in relapsed acute lymphoblastic leukemia

PubMed Central

Oshima, Koichi; Khiabanian, Hossein; da Silva-Almeida, Ana C.; Tzoneva, Gannie; Abate, Francesco; Ambesi-Impiombato, Alberto; Sanchez-Martin, Marta; Carpenter, Zachary; Penson, Alex; Perez-Garcia, Arianne; Eckert, Cornelia; Nicolas, Concepción; Balbin, Milagros; Sulis, Maria Luisa; Kato, Motohiro; Koh, Katsuyoshi; Paganin, Maddalena; Basso, Giuseppe; Gastier-Foster, Julie M.; Devidas, Meenakshi; Loh, Mignon L.; Kirschner-Schwabe, Renate; Palomero, Teresa; Rabadan, Raul; Ferrando, Adolfo A.

2016-01-01

Although multiagent combination chemotherapy is curative in a significant fraction of childhood acute lymphoblastic leukemia (ALL) patients, 20% of cases relapse and most die because of chemorefractory disease. Here we used whole-exome and whole-genome sequencing to analyze the mutational landscape at relapse in pediatric ALL cases. These analyses identified numerous relapse-associated mutated genes intertwined in chemotherapy resistance-related protein complexes. In this context, RAS-MAPK pathway-activating mutations in the neuroblastoma RAS viral oncogene homolog (NRAS), kirsten rat sarcoma viral oncogene homolog (KRAS), and protein tyrosine phosphatase, nonreceptor type 11 (PTPN11) genes were present in 24 of 55 (44%) cases in our series. Interestingly, some leukemias showed retention or emergence of RAS mutant clones at relapse, whereas in others RAS mutant clones present at diagnosis were replaced by RAS wild-type populations, supporting a role for both positive and negative selection evolutionary pressures in clonal evolution of RAS-mutant leukemia. Consistently, functional dissection of mouse and human wild-type and mutant RAS isogenic leukemia cells demonstrated induction of methotrexate resistance but also improved the response to vincristine in mutant RAS-expressing lymphoblasts. These results highlight the central role of chemotherapy-driven selection as a central mechanism of leukemia clonal evolution in relapsed ALL, and demonstrate a previously unrecognized dual role of RAS mutations as drivers of both sensitivity and resistance to chemotherapy. PMID:27655895

HLA class I-restricted MYD88 L265P-derived peptides as specific targets for lymphoma immunotherapy

PubMed Central

Nelde, Annika; Walz, Juliane Sarah; Kowalewski, Daniel Johannes; Schuster, Heiko; Wolz, Olaf-Oliver; Peper, Janet Kerstin; Cardona Gloria, Yamel; Langerak, Anton W.; Muggen, Alice F.; Claus, Rainer; Bonzheim, Irina; Fend, Falko; Salih, Helmut Rainer; Kanz, Lothar; Rammensee, Hans-Georg; Stevanović, Stefan; Weber, Alexander N. R.

2017-01-01

ABSTRACT Genome sequencing has uncovered an array of recurring somatic mutations in different non-Hodgkin lymphoma (NHL) subtypes. If affecting protein-coding regions, such mutations may yield mutation-derived peptides that may be presented by HLA class I proteins and recognized by cytotoxic T cells. A recurring somatic and oncogenic driver mutation of the Toll-like receptor adaptor protein MYD88, Leu265Pro (L265P) was identified in up to 90% of different NHL subtype patients. We therefore screened the potential of MYD88L265P-derived peptides to elicit cytotoxic T cell responses as tumor-specific neoantigens. Based on in silico predictions, we identified potential MYD88L265P-containing HLA ligands for several HLA class I restrictions. A set of HLA class I MYD88L265P-derived ligands elicited specific cytotoxic T cell responses for HLA-B*07 and -B*15. These data highlight the potential of MYD88L265P mutation-specific peptide-based immunotherapy as a novel personalized treatment approach for patients with MYD88L265P+ NHLs that may complement pharmacological approaches targeting oncogenic MyD88 L265P signaling. PMID:28405493

Prebiotics: A Novel Approach to Treat Hepatocellular Carcinoma

PubMed Central

2017-01-01

Hepatocellular carcinoma is one of the fatal malignancies and is considered as the third leading cause of death. Mutations, genetic modifications, dietary aflatoxins, or impairments in the regulation of oncogenic pathways may bring about liver cancer. An effective barrier against hepatotoxins is offered by gut-liver axis as a change in gut permeability and expanded translocation of lipopolysaccharides triggers the activation of Toll-like receptors which stimulate the process of hepatocarcinogenesis. Prebiotics, nondigestible oligosaccharides, have a pivotal role to play when it comes to inducing an antitumor effect. A healthy gut flora balance is imperative to downregulation of inflammatory cytokines and reducing lipopolysaccharides induced endotoxemia, thus inducing the antitumor effect. PMID:28573132

Functions of bromodomain-containing proteins and their roles in homeostasis and cancer.

PubMed

Fujisawa, Takao; Filippakopoulos, Panagis

2017-04-01

Bromodomains (BRDs) are evolutionarily conserved protein-protein interaction modules that are found in a wide range of proteins with diverse catalytic and scaffolding functions and are present in most tissues. BRDs selectively recognize and bind to acetylated Lys residues - particularly in histones - and thereby have important roles in the regulation of gene expression. BRD-containing proteins are frequently dysregulated in cancer, they participate in gene fusions that generate diverse, frequently oncogenic proteins, and many cancer-causing mutations have been mapped to the BRDs themselves. Importantly, BRDs can be targeted by small-molecule inhibitors, which has stimulated many translational research projects that seek to attenuate the aberrant functions of BRD-containing proteins in disease.

Drosophila photoreceptor axon guidance and targeting requires the dreadlocks SH2/SH3 adapter protein.

PubMed

Garrity, P A; Rao, Y; Salecker, I; McGlade, J; Pawson, T; Zipursky, S L

1996-05-31

Mutations in the Drosophila gene dreadlocks (dock) disrupt photoreceptor cell (R cell) axon guidance and targeting. Genetic mosaic analysis and cell-type-specific expression of dock transgenes demonstrate dock is required in R cells for proper innervation. Dock protein contains one SH2 and three SH3 domains, implicating it in tyrosine kinase signaling, and is highly related to the human proto-oncogene Nck. Dock expression is detected in R cell growth cones in the target region. We propose Dock transmits signals in the growth cone in response to guidance and targeting cues. These findings provide an important step for dissection of signaling pathways regulating growth cone motility.

Genomic characterization of explant tumorgraft models derived from fresh patient tumor tissue

PubMed Central

2012-01-01

Background There is resurgence within drug and biomarker development communities for the use of primary tumorgraft models as improved predictors of patient tumor response to novel therapeutic strategies. Despite perceived advantages over cell line derived xenograft models, there is limited data comparing the genotype and phenotype of tumorgrafts to the donor patient tumor, limiting the determination of molecular relevance of the tumorgraft model. This report directly compares the genomic characteristics of patient tumors and the derived tumorgraft models, including gene expression, and oncogenic mutation status. Methods Fresh tumor tissues from 182 cancer patients were implanted subcutaneously into immune-compromised mice for the development of primary patient tumorgraft models. Histological assessment was performed on both patient tumors and the resulting tumorgraft models. Somatic mutations in key oncogenes and gene expression levels of resulting tumorgrafts were compared to the matched patient tumors using the OncoCarta (Sequenom, San Diego, CA) and human gene microarray (Affymetrix, Santa Clara, CA) platforms respectively. The genomic stability of the established tumorgrafts was assessed across serial in vivo generations in a representative subset of models. The genomes of patient tumors that formed tumorgrafts were compared to those that did not to identify the possible molecular basis to successful engraftment or rejection. Results Fresh tumor tissues from 182 cancer patients were implanted into immune-compromised mice with forty-nine tumorgraft models that have been successfully established, exhibiting strong histological and genomic fidelity to the originating patient tumors. Comparison of the transcriptomes and oncogenic mutations between the tumorgrafts and the matched patient tumors were found to be stable across four tumorgraft generations. Not only did the various tumors retain the differentiation pattern, but supporting stromal elements were preserved. Those genes down-regulated specifically in tumorgrafts were enriched in biological pathways involved in host immune response, consistent with the immune deficiency status of the host. Patient tumors that successfully formed tumorgrafts were enriched for cell signaling, cell cycle, and cytoskeleton pathways and exhibited evidence of reduced immunogenicity. Conclusions The preservation of the patient’s tumor genomic profile and tumor microenvironment supports the view that primary patient tumorgrafts provide a relevant model to support the translation of new therapeutic strategies and personalized medicine approaches in oncology. PMID:22709571

KRAS mutations and CDKN2A promoter methylation show an interactive adverse effect on survival and predict recurrence of rectal cancer.

PubMed

Kohonen-Corish, Maija R J; Tseung, Jason; Chan, Charles; Currey, Nicola; Dent, Owen F; Clarke, Stephen; Bokey, Les; Chapuis, Pierre H

2014-06-15

Colonic and rectal cancers differ in their clinicopathologic features and treatment strategies. Molecular markers such as gene methylation, microsatellite instability and KRAS mutations, are becoming increasingly important in guiding treatment decisions in colorectal cancer. However, their association with clinicopathologic variables and utility in the management of rectal cancer is still poorly understood. We analyzed CDKN2A gene methylation, CpG island methylator phenotype (CIMP), microsatellite instability and KRAS/BRAF mutations in a cohort of 381 rectal cancers with extensive clinical follow-up data. BRAF mutations (2%), CIMP-high (4%) and microsatellite instability-high (2%) were rare, whereas KRAS mutations (39%), CDKN2A methylation (20%) and CIMP-low (25%) were more common. Only CDKN2A methylation and KRAS mutations showed an association with poor overall survival but these did not remain significant when analyzed with other clinicopathologic factors. In contrast, this prognostic effect was strengthened by the joint presence of CDKN2A methylation and KRAS mutations, which independently predicted recurrence of cancer and was associated with poor overall and cancer-specific survival. This study has identified a subgroup of more aggressive rectal cancers that may arise through the KRAS-p16 pathway. It has been previously shown that an interaction of p16 deficiency and oncogenic KRAS promotes carcinogenesis in the mouse and is characterized by loss of oncogene-induced senescence. These findings may provide avenues for the discovery of new treatments in rectal cancer. © 2013 UICC.

DNMT3A and IDH mutations in acute myeloid leukemia and other myeloid malignancies: associations with prognosis and potential treatment strategies

PubMed Central

Im, AP; Sehgal, AR; Carroll, MP; Smith, BD; Tefferi, A; Johnson, DE; Boyiadzis, M

2014-01-01

The development of effective treatment strategies for most forms of acute myeloid leukemia (AML) has languished for the past several decades. There are a number of reasons for this, but key among them is the considerable heterogeneity of this disease and the paucity of molecular markers that can be used to predict clinical outcomes and responsiveness to different therapies. The recent large-scale sequencing of AML genomes is now providing opportunities for patient stratification and personalized approaches to treatment that are based on individual mutational profiles. It is particularly notable that studies by The Cancer Genome Atlas and others have determined that 44% of patients with AML exhibit mutations in genes that regulate methylation of genomic DNA. In particular, frequent mutation has been observed in the genes encoding DNA methyltransferase 3A (DNMT3A), isocitrate dehydrogenase 1 (IDH1) and isocitrate dehydrogenase 2 (IDH2), as well as Tet oncogene family member 2. This review will summarize the incidence of these mutations, their impact on biochemical functions including epigenetic modification of genomic DNA and their potential usefulness as prognostic indicators. Importantly, the presence of DNMT3A, IDH1 or IDH2 mutations may confer sensitivity to novel therapeutic approaches, including the use of demethylating agents. Therefore, the clinical experience with decitabine and azacitidine in the treatment of patients harboring these mutations will be reviewed. Overall, we propose that understanding the role of these mutations in AML biology will lead to more rational therapeutic approaches targeting molecularly defined subtypes of the disease. PMID:24699305

Cytokinesis failure due to derailed integrin traffic induces aneuploidy and oncogenic transformation in vitro and in vivo

PubMed Central

Högnäs, G; Tuomi, S; Veltel, S; Mattila, E; Murumägi, A; Edgren, H; Kallioniemi, O; Ivaska, J

2012-01-01

Aneuploidy is frequently detected in solid tumors but the mechanisms regulating the generation of aneuploidy and their relevance in cancer initiation remain under debate and are incompletely characterized. Spatial and temporal regulation of integrin traffic is critical for cell migration and cytokinesis. Impaired integrin endocytosis, because of the loss of Rab21 small GTPase or mutations in the integrin β-subunit cytoplasmic tail, induces failure of cytokinesis in vitro. Here, we describe that repeatedly failed cytokinesis, because of impaired traffic, is sufficient to trigger the generation of aneuploid cells, which display characteristics of oncogenic transformation in vitro and are tumorigenic in vivo. Furthermore, in an in vivo mouse xenograft model, non-transformed cells with impaired integrin traffic formed tumors with a long latency. More detailed investigation of these tumors revealed that the tumor cells were aneuploid. Therefore, abnormal integrin traffic was linked with generation of aneuploidy and cell transformation also in vivo. In human prostate and ovarian cancer samples, downregulation of Rab21 correlates with increased malignancy. Loss-of-function experiments demonstrate that long-term depletion of Rab21 is sufficient to induce chromosome number aberrations in normal human epithelial cells. These data are the first to demonstrate that impaired integrin traffic is sufficient to induce conversion of non-transformed cells to tumorigenic cells in vitro and in vivo. PMID:22120710

Oncogenic transformation induced by cell-free nucleic acids circulating in plasma (genometastasis) remains after the surgical resection of the primary tumor: a pilot study.

PubMed

García-Olmo, Damián; García-Olmo, Dolores C; Domínguez-Berzosa, Carolina; Guadalajara, Hector; Vega, Luz; García-Arranz, Mariano

2012-06-01

The oncogenic transformation by cell-free nucleic acids circulating in plasma has been named as genometastasis. The feasibility of this phenomenon has been demonstrated and now it is necessary to value the impact of this phenomenon and to determine what conditions could promote or inhibit it. The goal of this study was to examine the transforming ability of plasma from colorectal cancer patients in a long-term follow-up after the surgical excision of the primary tumor, and to try correlate it with the clinical picture of patients. Blood samples were taken from eight patients with K-ras-mutated colorectal tumors, who were under surgical primary tumor resection at least 2 years before. Plasma was isolated by two centrifugations and added to cultures of NIH-3T3 cells and human adipose-derived stem cells (hASCs). In two cases, plasma was separated from cells by a membrane with 0.4-μm pores. The presence of mutated and non-mutated human K-ras sequences was tested by real-time PCR in cultured cells. After 30 days, cells were subcutaneously injected into athymic nude mice in order to test their ability to generate tumors. In four of the eight patients analyzed after surgery, tumor DNA was detected in plasma. Plasmas from three of them were able to oncogenically transform NIH-3T3 cells in culture and, when those cells were injected in mice, carcinomas were generated. After a 2-year follow-up, metastases were found in two of the three patients whose plasmas were able to transform cells, and in two of the four in whom plasma tumor DNA was not detected. Thus, after a mean follow-up of 29.5 months, only four of 13 patients (30.8%) were alive and disease-free. Primary tumor resection does not assure a complete clean of blood of circulating oncogenes, in spite of a disease-free clinical picture. Moreover, in some cases plasma kept their oncogenic capabilities. The value of these findings as prognosis factor remains unclear and needs further investigations.

The expression of SALL4 is significantly associated with EGFR, but not KRAS or EML4-ALK mutations in lung cancer.

PubMed

Jia, Xiangbo; Qian, Rulin; Zhang, Binbin; Zhao, Song

2016-10-01

Lung cancer is the leading cause of cancer-related deaths worldwide; unfortunately, its prognosis is still very poor. Therefore, developing the target molecular is very important for lung cancer diagnosis and treatment, especially in the early stage. With this in view, spalt-like transcription factor 4 ( SALL4 ) is considered a potential biomarker for diagnosis and prognosis in cancers, including lung cancer. In order to better investigate the association between the expression of SALL4 and driver genes mutation, 450 histopathologically diagnosed patients with lung cancer and 11 non-cancer patients were enrolled to test the expression of SALL4 and the status of driver genes mutation. This investigation included epidermal growth factor receptor ( EGFR ), kirsten rat sarcoma viral oncogene homolog ( KRAS ), and a fusion gene of the echinoderm microtubule-associated protein-like 4 ( EML4 ) and the anaplastic lymphoma kinase ( ALK ). The results of the study showed that females harbored more EGFR mutation in adenocarcinoma (ADC). The mutation rate of KRAS and EML4-ALK was about 5%, and the double mutations of EGFR/EML4-ALK were higher than EGFR/KRAS . In the expression analysis, the expression of SALL4 was much higher in cancer tissues than normally expected, especially in tissues that carried EGFR mutation (P<0.05), however, there were no significant differences between different mutation types. Likewise, there were no significant differences between expression of SALL4 and KRAS and EML4-ALK mutations. SALL4 is up regulated in lung cancer specimens and harbors EGFR mutation; this finding indicates that SALL4 expression may be relevant with EGFR , which could provide a new insight to lung cancer therapy. The mechanism needs further investigation and analysis.

Mixed adenoneuroendocrine carcinoma of the colon: molecular pathogenesis and treatment.

PubMed

Vanacker, Leen; Smeets, Dominiek; Hoorens, Anne; Teugels, Erik; Algaba, Roberto; Dehou, Marie Françoise; De Becker, Ann; Lambrechts, Diether; De Greve, Jacques

2014-10-01

We report a case of a mixed adenoneuroendocrine carcinoma developed in a colorectal adenocarcinoma with lymph node and liver metastases exclusively emanating from the neuroendocrine carcinoma component. The patient underwent right hemicolectomy and postoperatively received chemotherapy with cisplatin and etoposide and subsequent high-dose induction chemotherapy, followed by autologous stem cell transplantation. Following this treatment, there was a complete remission. Currently, thirty months after treatment, the patient is in unmaintained complete remission. Comparative exome sequencing of germline DNA and DNA from the two separate malignant components revealed six somatic changes in cancer consensus genes. Both components shared somatic mutations in Adenomatous polyposis coli (APC), Kirsten rat sarcoma viral oncogene homolog (KRAS), B-cell CLL/lymphoma 9 (BCL9) and Forkhead Box P1 (FOXP1) genes. Mutation in SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a, member 4 (SMARCA4) was only found in the neuroendocrine carcinoma component. The finding of several identical somatic mutations in both components supports a clonal relationship between the neuroendocrine carcinoma and the adenocarcinoma. We suggest that a mutation in SMARCA4 could be responsible for the transformation of the adenocarcinoma component into the neuroendocrine phenotype. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

The human tyrosine kinase Kit and its gatekeeper mutant T670I, show different kinetic properties: Implications for drug design.

PubMed

Kissova, Miroslava; Maga, Giovanni; Crespan, Emmanuele

2016-10-01

The tyrosine kinase Kit, a receptor for Stem Cell Factor, is involved, among others, in processes associated to cell survival, proliferation and migration. Upon physiological conditions, the activity of Kit is tightly regulated. However, primary mutations that lead to its constitutive activation are the causal oncogenic driver of gastrointestinal stromal tumours (GISTs). GISTs are known to be refractory to conventional therapies but the introduction of Imatinib, a selective inhibitor of tyrosine kinases Abl and Kit, significantly ameliorated the treatment options of GISTs patients. However, the acquisition of secondary mutations renders Kit resistant towards all available drugs. Mutation involving gatekeeper residues (such as V654a and T670I) influence both the structure and the catalytic activity of the enzyme. Therefore, detailed knowledge of the enzymatic properties of the mutant forms, in comparison with the wild type enzyme, is an important pre-requisite for the rational development of specific inhibitors. In this paper we report a thorough kinetic analysis of the reaction catalyzed by the Kit kinase and its gatekeeper mutated form T670I. Our results revealed the different mechanisms of action of these two enzymes and may open a new avenue for the future design of specific Kit inhibitors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Shared Oncogenic Pathways Implicated in Both Virus-Positive and UV-Induced Merkel Cell Carcinomas.

PubMed

González-Vela, María Del Carmen; Curiel-Olmo, Soraya; Derdak, Sophia; Beltran, Sergi; Santibañez, Miguel; Martínez, Nerea; Castillo-Trujillo, Alfredo; Gut, Martha; Sánchez-Pacheco, Roxana; Almaraz, Carmen; Cereceda, Laura; Llombart, Beatriz; Agraz-Doblas, Antonio; Revert-Arce, José; López Guerrero, José Antonio; Mollejo, Manuela; Marrón, Pablo Isidro; Ortiz-Romero, Pablo; Fernandez-Cuesta, Lynnette; Varela, Ignacio; Gut, Ivo; Cerroni, Lorenzo; Piris, Miguel Ángel; Vaqué, José Pedro

2017-01-01

Merkel cell carcinoma (MCC) is a highly malignant neuroendocrine tumor of the skin whose molecular pathogenesis is not completely understood, despite the role that Merkel cell polyomavirus can play in 55-90% of cases. To study potential mechanisms driving this disease in clinically characterized cases, we searched for somatic mutations using whole-exome sequencing, and extrapolated our findings to study functional biomarkers reporting on the activity of the mutated pathways. Confirming previous results, Merkel cell polyomavirus-negative tumors had higher mutational loads with UV signatures and more frequent mutations in TP53 and RB compared with their Merkel cell polyomavirus-positive counterparts. Despite important genetic differences, the two Merkel cell carcinoma etiologies both exhibited nuclear accumulation of oncogenic transcription factors such as NFAT or nuclear factor of activated T cells (NFAT), P-CREB, and P-STAT3, indicating commonly deregulated pathogenic mechanisms with the potential to serve as targets for therapy. A multivariable analysis identified phosphorylated CRE-binding protein as an independent survival factor with respect to clinical variables and Merkel cell polyomavirus status in our cohort of Merkel cell carcinoma patients. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Oncogenic RAS Enables DNA Damage- and p53-Dependent Differentiation of Acute Myeloid Leukemia Cells in Response to Chemotherapy

PubMed Central

Meyer, Mona; Rübsamen, Daniela; Slany, Robert; Illmer, Thomas; Stabla, Kathleen; Roth, Petra; Stiewe, Thorsten

2009-01-01

Acute myeloid leukemia (AML) is a clonal disease originating from myeloid progenitor cells with a heterogeneous genetic background. High-dose cytarabine is used as the standard consolidation chemotherapy. Oncogenic RAS mutations are frequently observed in AML, and are associated with beneficial response to cytarabine. Why AML-patients with oncogenic RAS benefit most from high-dose cytarabine post-remission therapy is not well understood. Here we used bone marrow cells expressing a conditional MLL-ENL-ER oncogene to investigate the interaction of oncogenic RAS and chemotherapeutic agents. We show that oncogenic RAS synergizes with cytotoxic agents such as cytarabine in activation of DNA damage checkpoints, resulting in a p53-dependent genetic program that reduces clonogenicity and increases myeloid differentiation. Our data can explain the beneficial effects observed for AML patients with oncogenic RAS treated with higher dosages of cytarabine and suggest that induction of p53-dependent differentiation, e.g. by interfering with Mdm2-mediated degradation, may be a rational approach to increase cure rate in response to chemotherapy. The data also support the notion that the therapeutic success of cytotoxic drugs may depend on their ability to promote the differentiation of tumor-initiating cells. PMID:19890398

Exosomes Facilitate Therapeutic Targeting of Oncogenic Kras in Pancreatic Cancer

PubMed Central

Kamerkar, Sushrut; LeBleu, Valerie S.; Sugimoto, Hikaru; Yang, Sujuan; Ruivo, Carolina F.; Melo, Sonia A.; Lee, J. Jack; Kalluri, Raghu

2017-01-01

Summary The mutant form of the GTPase KRAS is a key driver of pancreatic cancer but remains a challenging therapeutic target. Exosomes, extracellular vesicles generated by all cells, are naturally present in the blood. Here we demonstrate that enhanced retention of exosomes in circulation, compared to liposomes, is due to CD47 mediated protection of exosomes from phagocytosis by monocytes and macrophages. Exosomes derived from normal fibroblast-like mesenchymal cells were engineered to carry siRNA or shRNA specific to oncogenic KRASG12D (iExosomes), a common mutation in pancreatic cancer. Compared to liposomes, iExosomes target oncogenic Kras with an enhanced efficacy that is dependent on CD47, and is facilitated by macropinocytosis. iExosomes treatment suppressed cancer in multiple mouse models of pancreatic cancer and significantly increased their overall survival. Our results inform on a novel approach for direct and specific targeting of oncogenic Kras in tumors using iExosomes. PMID:28607485

PIK3CA Mutations in Mucinous Cystic Neoplasms of the Pancreas

PubMed Central

Garcia-Carracedo, Dario; Chen, Zong-Ming; Qiu, Wanglong; Huang, Alicia S.; Tang, Sophia M.; Hruban, Ralph H.; Su, Gloria H.

2014-01-01

Objectives Mucinous cystic neoplasms (MCNs) are rare, potentially curable, mucin-producing neoplasms of the pancreas. We have previously reported PIK3CA (phosphoinositide-3-kinase catalytic subunit, p110α) mutations in intraductal papillary mucinous neoplasms, another mucin-producing neoplasm of the pancreas. In this study, we analyzed the presence of PIK3CA and AKT1/PKB (V-akt murine thymoma viral oncogene homolog 1) hot-spot mutations in MCN specimens. Methods Using the genomic DNA sequencing of tumor tissues isolated by laser capture microdissection, we evaluated 15 well-characterized MCNs for the E542K, E545K(exon 9), and H1047R (exon 20) hot-spotmutations in the PIK3CA gene and the E17K mutation in the AKT1 gene. Results A hot-spotmutation (E545K) of the PIK3CA gene was detected in 1 of the 15 MCNs and further confirmed by a mutant-enriched method. Interestingly, this mutation was found to be present only in the high-grade but not in low-grade dysplastic epithelium obtained from this neoplasm and coexisted with a KRASG12D mutation. No mutations were identified in the AKT1 gene. Conclusions Our data, when combined with previous reports on intraductal papillary mucinous neoplasms, indicate that oncogenic activation of the PI3K pathway involving PIK3CA gene mutations can contribute to the progression of mucin-producing neoplasms but not pancreatic intraepithelial neoplasia. PIK3CA status could be useful for understanding their progression to malignancy. PMID:24518503

Establishing high resolution melting analysis: method validation and evaluation for c-RET proto-oncogene mutation screening.

PubMed

Benej, Martin; Bendlova, Bela; Vaclavikova, Eliska; Poturnajova, Martina

2011-10-06

Reliable and effective primary screening of mutation carriers is the key condition for common diagnostic use. The objective of this study is to validate the method high resolution melting (HRM) analysis for routine primary mutation screening and accomplish its optimization, evaluation and validation. Due to their heterozygous nature, germline point mutations of c-RET proto-oncogene, associated to multiple endocrine neoplasia type 2 (MEN2), are suitable for HRM analysis. Early identification of mutation carriers has a major impact on patients' survival due to early onset of medullary thyroid carcinoma (MTC) and resistance to conventional therapy. The authors performed a series of validation assays according to International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) guidelines for validation of analytical procedures, along with appropriate design and optimization experiments. After validated evaluation of HRM, the method was utilized for primary screening of 28 pathogenic c-RET mutations distributed among nine exons of c-RET gene. Validation experiments confirm the repeatability, robustness, accuracy and reproducibility of HRM. All c-RET gene pathogenic variants were detected with no occurrence of false-positive/false-negative results. The data provide basic information about design, establishment and validation of HRM for primary screening of genetic variants in order to distinguish heterozygous point mutation carriers among the wild-type sequence carriers. HRM analysis is a powerful and reliable tool for rapid and cost-effective primary screening, e.g., of c-RET gene germline and/or sporadic mutations and can be used as a first line potential diagnostic tool.

Structure-Based Analysis Reveals Cancer Missense Mutations Target Protein Interaction Interfaces.

PubMed

Engin, H Billur; Kreisberg, Jason F; Carter, Hannah

2016-01-01

Recently it has been shown that cancer mutations selectively target protein-protein interactions. We hypothesized that mutations affecting distinct protein interactions involving established cancer genes could contribute to tumor heterogeneity, and that novel mechanistic insights might be gained into tumorigenesis by investigating protein interactions under positive selection in cancer. To identify protein interactions under positive selection in cancer, we mapped over 1.2 million nonsynonymous somatic cancer mutations onto 4,896 experimentally determined protein structures and analyzed their spatial distribution. In total, 20% of mutations on the surface of known cancer genes perturbed protein-protein interactions (PPIs), and this enrichment for PPI interfaces was observed for both tumor suppressors (Odds Ratio 1.28, P-value < 10(-4)) and oncogenes (Odds Ratio 1.17, P-value < 10(-3)). To study this further, we constructed a bipartite network representing structurally resolved PPIs from all available human complexes in the Protein Data Bank (2,864 proteins, 3,072 PPIs). Analysis of frequently mutated cancer genes within this network revealed that tumor-suppressors, but not oncogenes, are significantly enriched with functional mutations in homo-oligomerization regions (Odds Ratio 3.68, P-Value < 10(-8)). We present two important examples, TP53 and beta-2-microglobulin, for which the patterns of somatic mutations at interfaces provide insights into specifically perturbed biological circuits. In patients with TP53 mutations, patient survival correlated with the specific interactions that were perturbed. Moreover, we investigated mutations at the interface of protein-nucleotide interactions and observed an unexpected number of missense mutations but not silent mutations occurring within DNA and RNA binding sites. Finally, we provide a resource of 3,072 PPI interfaces ranked according to their mutation rates. Analysis of this list highlights 282 novel candidate cancer genes that encode proteins participating in interactions that are perturbed recurrently across tumors. In summary, mutation of specific protein interactions is an important contributor to tumor heterogeneity and may have important implications for clinical outcomes.

RB mutation and RAS overexpression induce resistance to NK cell-mediated cytotoxicity in glioma cells.

PubMed

Orozco-Morales, Mario; Sánchez-García, Francisco Javier; Golán-Cancela, Irene; Hernández-Pedro, Norma; Costoya, Jose A; de la Cruz, Verónica Pérez; Moreno-Jiménez, Sergio; Sotelo, Julio; Pineda, Benjamín

2015-01-01

Several theories aim to explain the malignant transformation of cells, including the mutation of tumor suppressors and proto-oncogenes. Deletion of Rb (a tumor suppressor), overexpression of mutated Ras (a proto-oncogene), or both, are sufficient for in vitro gliomagenesis, and these genetic traits are associated with their proliferative capacity. An emerging hallmark of cancer is the ability of tumor cells to evade the immune system. Whether specific mutations are related with this, remains to be analyzed. To address this issue, three transformed glioma cell lines were obtained (Rb(-/-), Ras(V12), and Rb(-/-)/Ras(V12)) by in vitro retroviral transformation of astrocytes, as previously reported. In addition, Ras(V12) and Rb(-/-)/Ras(V12) transformed cells were injected into SCID mice and after tumor growth two stable glioma cell lines were derived. All these cells were characterized in terms of Rb and Ras gene expression, morphology, proliferative capacity, expression of MHC I, Rae1δ, and Rae1αβγδε, mult1, H60a, H60b, H60c, as ligands for NK cell receptors, and their susceptibility to NK cell-mediated cytotoxicity. Our results show that transformation of astrocytes (Rb loss, Ras overexpression, or both) induced phenotypical and functional changes associated with resistance to NK cell-mediated cytotoxicity. Moreover, the transfer of cell lines of transformed astrocytes into SCID mice increased resistance to NK cell-mediated cytotoxicity, thus suggesting that specific changes in a tumor suppressor (Rb) and a proto-oncogene (Ras) are enough to confer resistance to NK cell-mediated cytotoxicity in glioma cells and therefore provide some insight into the ability of tumor cells to evade immune responses.

Altered molecular profile in thyroid cancers from patients affected by the Three Mile Island nuclear accident.

PubMed

Goldenberg, David; Russo, Mariano; Houser, Kenneth; Crist, Henry; Derr, Jonathan B; Walter, Vonn; Warrick, Joshua I; Sheldon, Kathryn E; Broach, James; Bann, Darrin V

2017-07-01

In 1979, Three Mile Island (TMI) nuclear power plant experienced a partial meltdown with release of radioactive material. The effects of the accident on thyroid cancer (TC) in the surrounding population remain unclear. Radiation-induced TCs have a lower incidence of single nucleotide oncogenic driver mutations and higher incidence of gene fusions. We used next generation sequencing (NGS) to identify molecular signatures of radiation-induced TC in a cohort of TC patients residing near TMI during the time of the accident. Case series. We identified 44 patients who developed papillary thyroid carcinoma between 1974 and 2014. Patients who developed TC between 1984 and 1996 were at risk for radiation-induced TC, patients who developed TC before 1984 or after 1996 were the control group. We used targeted NGS of paired tumor and normal tissue from each patient to identify single nucleotide oncogenic driver mutations. Oncogenic gene fusions were identified using quantitative reverse transcription polymerase chain reaction. We identified 15 patients in the at-risk group and 29 patients in the control group. BRAF V600E mutations were identified in 53% patients in the at-risk group and 83% patients in the control group. The proportion of patients with BRAF mutations in the at-risk group was significantly lower than predicted by the The Cancer Genome Atlas cohort. Gene fusion or somatic copy number alteration drivers were identified in 33% tumors in the at-risk group and 14% of tumors in the control group. Findings were consistent with observations from other radiation-exposed populations. These data raise the possibility that radiation released from TMI may have altered the molecular profile of TC in the population surrounding TMI. 4 Laryngoscope, 127:S1-S9, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Cancer therapy based on oncogene addiction.

PubMed

McCormick, Frank

2011-05-01

Tumor cells contain multiple mutations, yet they often depend on continued expressed of a single oncoprotein for survival. Targeting these proteins has led to dramatic responses. Unfortunately, patients usually progress, through drug resistance or adaptive resistance through reprogramming of signaling networks. The Ras-MAPK pathway provides examples of these successes and failures, and has revealed unexpected degrees of oncogene addiction and signaling complexity that are likely to be useful lessons for the future of targeted therapy. Copyright © 2011 Wiley-Liss, Inc.

Characterizing genomic alterations in cancer by complementary functional associations | Office of Cancer Genomics

Cancer.gov

Systematic efforts to sequence the cancer genome have identified large numbers of mutations and copy number alterations in human cancers. However, elucidating the functional consequences of these variants, and their interactions to drive or maintain oncogenic states, remains a challenge in cancer research. We developed REVEALER, a computational method that identifies combinations of mutually exclusive genomic alterations correlated with functional phenotypes, such as the activation or gene dependency of oncogenic pathways or sensitivity to a drug treatment.

Systematic RNA interference reveals that oncogenic KRAS-driven cancers require TBK1

PubMed Central

Barbie, David A.; Tamayo, Pablo; Boehm, Jesse S.; Kim, So Young; Moody, Susan E.; Dunn, Ian F.; Schinzel, Anna C.; Sandy, Peter; Meylan, Etienne; Scholl, Claudia; Fröhling, Stefan; Chan, Edmond M.; Sos, Martin L.; Michel, Kathrin; Mermel, Craig; Silver, Serena J.; Weir, Barbara A.; Reiling, Jan H.; Sheng, Qing; Gupta, Piyush B.; Wadlow, Raymond C.; Le, Hanh; Hoersch, Sebastian; Wittner, Ben S.; Ramaswamy, Sridhar; Livingston, David M.; Sabatini, David M.; Meyerson, Matthew; Thomas, Roman K.; Lander, Eric S.; Mesirov, Jill P.; Root, David E.; Gilliland, D. Gary; Jacks, Tyler; Hahn, William C.

2009-01-01

The proto-oncogene KRAS is mutated in a wide array of human cancers, most of which are aggressive and respond poorly to standard therapies. Although the identification of specific oncogenes has led to the development of clinically effective, molecularly targeted therapies in some cases, KRAS has remained refractory to this approach. A complementary strategy for targeting KRAS is to identify gene products that, when inhibited, result in cell death only in the presence of an oncogenic allele1,2. Here we have used systematic RNA interference (RNAi) to detect synthetic lethal partners of oncogenic KRAS and found that the non-canonical IκB kinase, TBK1, was selectively essential in cells that harbor mutant KRAS. Suppression of TBK1 induced apoptosis specifically in human cancer cell lines that depend on oncogenic KRAS expression. In these cells, TBK1 activated NF-κB anti-apoptotic signals involving cREL and BCL-XL that were essential for survival, providing mechanistic insights into this synthetic lethal interaction. These observations identify TBK1 and NF-κB signaling as essential in KRAS mutant tumors and establish a general approach for the rational identification of co-dependent pathways in cancer. PMID:19847166

XMEN disease: a new primary immunodeficiency affecting Mg2+ regulation of immunity against Epstein-Barr virus.

PubMed

Li, Feng-Yen; Chaigne-Delalande, Benjamin; Su, Helen; Uzel, Gulbu; Matthews, Helen; Lenardo, Michael J

2014-04-03

Epstein-Barr virus (EBV) is an oncogenic gammaherpesvirus that infects and persists in 95% of adults worldwide and has the potential to cause fatal disease, especially lymphoma, in immunocompromised hosts. Primary immunodeficiencies (PIDs) that predispose to EBV-associated malignancies have provided novel insights into the molecular mechanisms of immune defense against EBV. We have recently characterized a novel PID now named "X-linked immunodeficiency with magnesium defect, EBV infection, and neoplasia" (XMEN) disease characterized by loss-of-function mutations in the gene encoding magnesium transporter 1 (MAGT1), chronic high-level EBV with increased EBV-infected B cells, and heightened susceptibility to EBV-associated lymphomas. The genetic etiology of XMEN disease has revealed an unexpected quantitative role for intracellular free magnesium in immune functions and has led to novel diagnostic and therapeutic strategies. Here, we review the clinical presentation, genetic mutation spectrum, molecular mechanisms of pathogenesis, and diagnostic and therapeutic considerations for this previously unrecognized disease.

Decoding the genetic basis of Cushing's disease: USP8 in the spotlight.

PubMed

Theodoropoulou, Marily; Reincke, Martin; Fassnacht, Martin; Komada, Masayuki

2015-10-01

Cushing's disease (CD) arises from pituitary-dependent glucocorticoid excess due to an ACTH-secreting corticotroph tumor. Genetic hits in oncogenes and tumor suppressor genes that afflict other pituitary tumor subtypes are not found in corticotrophinomas. Recently, a somatic mutational hotspot was found in up to half of corticotrophinomas in the USP8 gene that encodes a protein that impairs the downregulation of the epidermal growth factor receptor (EGFR) and enables its constitutive signaling. EGF is an important regulator of corticotroph function and its receptor is highly expressed in Cushing's pituitary tumors, where it leads to increased ACTH synthesis in vitro and in vivo. The mutational hotspot found in corticotrophinomas hyper-activates USP8, enabling it to rescue EGFR from lysosomal degradation and ensure its stimulatory signaling. This review presents new developments in the study of the genetics of CD and focuses on the USP8-EGFR system as trigger and target of corticotroph tumorigenesis. © 2015 European Society of Endocrinology.

CRISPR/Cas9 and cancer targets: future possibilities and present challenges.

PubMed

White, Martyn K; Khalili, Kamel

2016-03-15

All cancers have multiple mutations that can largely be grouped into certain classes depending on the function of the gene in which they lie and these include oncogenic changes that enhance cellular proliferation, loss of function of tumor suppressors that regulate cell growth potential and induction of metabolic enzymes that confer resistance to chemotherapeutic agents. Thus the ability to correct such mutations is an important goal in cancer treatment. Recent research has led to the developments of reagents which specifically target nucleotide sequences within the cellular genome and these have a huge potential for expanding our anticancer armamentarium. One such a reagent is the clustered regulatory interspaced short palindromic repeat (CRISPR)-associated 9 (Cas9) system, a powerful, highly specific and adaptable tool that provides unparalleled control for editing the cellular genome. In this short review, we discuss the potential of CRISPR/Cas9 against human cancers and the current difficulties in translating this for novel therapeutic approaches.

Differences in the Regulation of K-Ras and H-Ras Isoforms by Monoubiquitination*

PubMed Central

Baker, Rachael; Wilkerson, Emily M.; Sumita, Kazutaka; Isom, Daniel G.; Sasaki, Atsuo T.; Dohlman, Henrik G.; Campbell, Sharon L.

2013-01-01

Ras GTPases are signaling switches that control critical cellular processes including gene expression, differentiation, and apoptosis. The major Ras isoforms (K, H, and N) contain a conserved core GTPase domain, but have distinct biological functions. Among the three Ras isoforms there are clear differences in post-translational regulation, which contribute to differences in localization and signaling output. Modification by ubiquitination was recently reported to activate Ras signaling in cells, but the mechanisms of activation are not well understood. Here, we show that H-Ras is activated by monoubiquitination and that ubiquitination at Lys-117 accelerates intrinsic nucleotide exchange, thereby promoting GTP loading. This mechanism of Ras activation is distinct from K-Ras monoubiquitination at Lys-147, which leads to impaired regulator-mediated GTP hydrolysis. These findings reveal that different Ras isoforms are monoubiquitinated at distinct sites, with distinct mechanisms of action, but with a common ability to chronically activate the protein in the absence of a receptor signal or oncogenic mutation. PMID:24247240

Altered MENIN expression disrupts the MAFA differentiation pathway in insulinoma.

PubMed

Hamze, Z; Vercherat, C; Bernigaud-Lacheretz, A; Bazzi, W; Bonnavion, R; Lu, J; Calender, A; Pouponnot, C; Bertolino, P; Roche, C; Stein, R; Scoazec, J Y; Zhang, C X; Cordier-Bussat, M

2013-12-01

The protein MENIN is the product of the multiple endocrine neoplasia type I (MEN1) gene. Altered MENIN expression is one of the few events that are clearly associated with foregut neuroendocrine tumours (NETs), classical oncogenes or tumour suppressors being not involved. One of the current challenges is to understand how alteration of MENIN expression contributes to the development of these tumours. We hypothesised that MENIN might regulate factors maintaining endocrine-differentiated functions. We chose the insulinoma model, a paradigmatic example of well-differentiated pancreatic NETs, to study whether MENIN interferes with the expression of v-MAF musculoaponeurotic fibrosarcoma oncogene homologue A (MAFA), a master glucose-dependent transcription factor in differentiated β-cells. Immunohistochemical analysis of a series of human insulinomas revealed a correlated decrease in both MENIN and MAFA. Decreased MAFA expression resulting from targeted Men1 ablation was also consistently observed in mouse insulinomas. In vitro analyses using insulinoma cell lines showed that MENIN regulated MAFA protein and mRNA levels, and bound to Mafa promoter sequences. MENIN knockdown concomitantly decreased mRNA expression of both Mafa and β-cell differentiation markers (Ins1/2, Gck, Slc2a2 and Pdx1) and, in parallel, increased the proliferation rate of tumours as measured by bromodeoxyuridine incorporation. Interestingly, MAFA knockdown alone also increased proliferation rate but did not affect the expression of candidate proliferation genes regulated by MENIN. Finally, MENIN variants with missense mutations detected in patients with MEN1 lost the WT MENIN properties to regulate MAFA. Together, our findings unveil a previously unsuspected MENIN/MAFA connection regarding control of the β-cell differentiation/proliferation balance, which could contribute to tumorigenesis.

Somatic mutation of EZH2 (Y641) in follicular and diffuse large B-cell lymphomas of germinal center origin | Office of Cancer Genomics

Cancer.gov

Morin et al. describe recurrent somatic mutations in EZH2, a polycomb group oncogene. The mutation, found in the SET domain of this gene encoding a histone methyltransferase, is found only in a subset of lymphoma samples. Specifically, EZH2 mutations are found in about 12% of follicular lymphomas (FL) and almost 23% of diffuse large B-cell lymphomas (DLBCL) of germinal center origin. This paper goes on to demonstrate that altered EZH2 proteins, corresponding to the most frequent mutations found in human lymphomas, have reduced activity using in vitro histone methylation assays.

Serine/Arginine-Rich Splicing Factor 3 and Heterogeneous Nuclear Ribonucleoprotein A1 Regulate Alternative RNA Splicing and Gene Expression of Human Papillomavirus 18 through Two Functionally Distinguishable cis Elements.

PubMed

Ajiro, Masahiko; Tang, Shuang; Doorbar, John; Zheng, Zhi-Ming

2016-10-15

Human papillomavirus 18 (HPV18) is the second most common oncogenic HPV type associated with cervical, anogenital, and oropharyngeal cancers. Like other oncogenic HPVs, HPV18 encodes two major (one early and one late) polycistronic pre-mRNAs that are regulated by alternative RNA splicing to produce a repertoire of viral transcripts for the expression of individual viral genes. However, RNA cis-regulatory elements and trans-acting factors contributing to HPV18 alternative RNA splicing remain unknown. In this study, an exonic splicing enhancer (ESE) in the nucleotide (nt) 3520 to 3550 region in the HPV18 genome was identified and characterized for promotion of HPV18 929^3434 splicing and E1^E4 production through interaction with SRSF3, a host oncogenic splicing factor differentially expressed in epithelial cells and keratinocytes. Introduction of point mutations in the SRSF3-binding site or knockdown of SRSF3 expression in cells reduces 929^3434 splicing and E1^E4 production but activates other, minor 929^3465 and 929^3506 splicing. Knockdown of SRSF3 expression also enhances the expression of E2 and L1 mRNAs. An exonic splicing silencer (ESS) in the HPV18 nt 612 to 639 region was identified as being inhibitory to the 233^416 splicing of HPV18 E6E7 pre-mRNAs via binding to hnRNP A1, a well-characterized, abundantly and ubiquitously expressed RNA-binding protein. Introduction of point mutations into the hnRNP A1-binding site or knockdown of hnRNP A1 expression promoted 233^416 splicing and reduced E6 expression. These data provide the first evidence that the alternative RNA splicing of HPV18 pre-mRNAs is subject to regulation by viral RNA cis elements and host trans-acting splicing factors. Expression of HPV18 genes is regulated by alternative RNA splicing of viral polycistronic pre-mRNAs to produce a repertoire of viral early and late transcripts. RNA cis elements and trans-acting factors contributing to HPV18 alternative RNA splicing have been discovered in this study for the first time. The identified ESS at the E7 open reading frame (ORF) prevents HPV18 233^416 splicing in the E6 ORF through interaction with a host splicing factor, hnRNP A1, and regulates E6 and E7 expression of the early E6E7 polycistronic pre-mRNA. The identified ESE at the E1^E4 ORF promotes HPV18 929^3434 splicing of both viral early and late pre-mRNAs and E1^E4 production through interaction with SRSF3. This study provides important observations on how alternative RNA splicing of HPV18 pre-mRNAs is subject to regulation by viral RNA cis elements and host splicing factors and offers potential therapeutic targets to overcome HPV-related cancer. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Serine/Arginine-Rich Splicing Factor 3 and Heterogeneous Nuclear Ribonucleoprotein A1 Regulate Alternative RNA Splicing and Gene Expression of Human Papillomavirus 18 through Two Functionally Distinguishable cis Elements

PubMed Central

Ajiro, Masahiko; Tang, Shuang; Doorbar, John

2016-01-01

ABSTRACT Human papillomavirus 18 (HPV18) is the second most common oncogenic HPV type associated with cervical, anogenital, and oropharyngeal cancers. Like other oncogenic HPVs, HPV18 encodes two major (one early and one late) polycistronic pre-mRNAs that are regulated by alternative RNA splicing to produce a repertoire of viral transcripts for the expression of individual viral genes. However, RNA cis-regulatory elements and trans-acting factors contributing to HPV18 alternative RNA splicing remain unknown. In this study, an exonic splicing enhancer (ESE) in the nucleotide (nt) 3520 to 3550 region in the HPV18 genome was identified and characterized for promotion of HPV18 929^3434 splicing and E1^E4 production through interaction with SRSF3, a host oncogenic splicing factor differentially expressed in epithelial cells and keratinocytes. Introduction of point mutations in the SRSF3-binding site or knockdown of SRSF3 expression in cells reduces 929^3434 splicing and E1^E4 production but activates other, minor 929^3465 and 929^3506 splicing. Knockdown of SRSF3 expression also enhances the expression of E2 and L1 mRNAs. An exonic splicing silencer (ESS) in the HPV18 nt 612 to 639 region was identified as being inhibitory to the 233^416 splicing of HPV18 E6E7 pre-mRNAs via binding to hnRNP A1, a well-characterized, abundantly and ubiquitously expressed RNA-binding protein. Introduction of point mutations into the hnRNP A1-binding site or knockdown of hnRNP A1 expression promoted 233^416 splicing and reduced E6 expression. These data provide the first evidence that the alternative RNA splicing of HPV18 pre-mRNAs is subject to regulation by viral RNA cis elements and host trans-acting splicing factors. IMPORTANCE Expression of HPV18 genes is regulated by alternative RNA splicing of viral polycistronic pre-mRNAs to produce a repertoire of viral early and late transcripts. RNA cis elements and trans-acting factors contributing to HPV18 alternative RNA splicing have been discovered in this study for the first time. The identified ESS at the E7 open reading frame (ORF) prevents HPV18 233^416 splicing in the E6 ORF through interaction with a host splicing factor, hnRNP A1, and regulates E6 and E7 expression of the early E6E7 polycistronic pre-mRNA. The identified ESE at the E1^E4 ORF promotes HPV18 929^3434 splicing of both viral early and late pre-mRNAs and E1^E4 production through interaction with SRSF3. This study provides important observations on how alternative RNA splicing of HPV18 pre-mRNAs is subject to regulation by viral RNA cis elements and host splicing factors and offers potential therapeutic targets to overcome HPV-related cancer. PMID:27489271

The fanconi anemia pathway limits human papillomavirus replication.

PubMed

Hoskins, Elizabeth E; Morreale, Richard J; Werner, Stephen P; Higginbotham, Jennifer M; Laimins, Laimonis A; Lambert, Paul F; Brown, Darron R; Gillison, Maura L; Nuovo, Gerard J; Witte, David P; Kim, Mi-Ok; Davies, Stella M; Mehta, Parinda A; Butsch Kovacic, Melinda; Wikenheiser-Brokamp, Kathryn A; Wells, Susanne I

2012-08-01

High-risk human papillomaviruses (HPVs) deregulate epidermal differentiation and cause anogenital and head and neck squamous cell carcinomas (SCCs). The E7 gene is considered the predominant viral oncogene and drives proliferation and genome instability. While the implementation of routine screens has greatly reduced the incidence of cervical cancers which are almost exclusively HPV positive, the proportion of HPV-positive head and neck SCCs is on the rise. High levels of HPV oncogene expression and genome load are linked to disease progression, but genetic risk factors that regulate oncogene abundance and/or genome amplification remain poorly understood. Fanconi anemia (FA) is a genome instability syndrome characterized at least in part by extreme susceptibility to SCCs. FA results from mutations in one of 15 genes in the FA pathway, whose protein products assemble in the nucleus and play important roles in DNA damage repair. We report here that loss of FA pathway components FANCA and FANCD2 stimulates E7 protein accumulation in human keratinocytes and causes increased epithelial proliferation and basal cell layer expansion in the HPV-positive epidermis. Additionally, FANCD2 loss stimulates HPV genome amplification in differentiating cells, demonstrating that the intact FA pathway functions to restrict the HPV life cycle. These findings raise the possibility that FA genes suppress HPV infection and disease and suggest possible mechanism(s) for reported associations of HPV with an FA cohort in Brazil and for allelic variation of FA genes with HPV persistence in the general population.

Protein stabilization by RSUME accounts for PTTG pituitary tumor abundance and oncogenicity.

PubMed

Fuertes, M; Sapochnik, M; Tedesco, L; Senin, S; Attorresi, A; Ajler, P; Carrizo, G; Cervio, A; Sevlever, G; Bonfiglio, J J; Stalla, G K; Arzt, E

2018-06-01

Increased levels of the proto-oncogene pituitary tumor-transforming gene 1 (PTTG) have been repeatedly reported in several human solid tumors, especially in endocrine-related tumors such as pituitary adenomas. Securin PTTG has a critical role in pituitary tumorigenesis. However, the cause of upregulation has not been found yet, despite analyses made at the gene, promoter and mRNA level that show that no mutations, epigenetic modifications or other mechanisms that deregulate its expression may explain its overexpression and action as an oncogene. We describe that high PTTG protein levels are induced by the RWD-containing sumoylation enhancer (RWDD3 or RSUME), a protein originally identified in the same pituitary tumor cell line in which PTTG was also cloned. We demonstrate that PTTG and RSUME have a positive expression correlation in human pituitary adenomas. RSUME increases PTTG protein in pituitary tumor cell lines, prolongs the half-life of PTTG protein and regulates the PTTG induction by estradiol. As a consequence, RSUME enhances PTTG transcription factor and securin activities. PTTG hyperactivity on the cell cycle resulted in recurrent and unequal divisions without cytokinesis, and the consequential appearance of aneuploidies and multinucleated cells in the tumor. RSUME knockdown diminishes securin PTTG and reduces its tumorigenic potential in a xenograft mouse model. Taken together, our findings show that PTTG high protein steady state levels account for PTTG tumor abundance and demonstrate a critical role of RSUME in this process in pituitary tumor cells. © 2018 Society for Endocrinology.

Combined transcriptome studies identify AFF3 as a mediator of the oncogenic effects of β-catenin in adrenocortical carcinoma

PubMed Central

Lefèvre, L; Omeiri, H; Drougat, L; Hantel, C; Giraud, M; Val, P; Rodriguez, S; Perlemoine, K; Blugeon, C; Beuschlein, F; de Reyniès, A; Rizk-Rabin, M; Bertherat, J; Ragazzon, B

2015-01-01

Adrenocortical cancer (ACC) is a very aggressive tumor, and genomics studies demonstrate that the most frequent alterations of driver genes in these cancers activate the Wnt/β-catenin signaling pathway. However, the adrenal-specific targets of oncogenic β-catenin-mediating tumorigenesis have not being established. A combined transcriptomic analysis from two series of human tumors and the human ACC cell line H295R harboring a spontaneous β-catenin activating mutation was done to identify the Wnt/β-catenin targets. Seven genes were consistently identified in the three studies. Among these genes, we found that AFF3 mediates the oncogenic effects of β-catenin in ACC. The Wnt response element site located at nucleotide position −1408 of the AFF3 transcriptional start sites (TSS) mediates the regulation by the Wnt/β-catenin signaling pathway. AFF3 silencing decreases cell proliferation and increases apoptosis in the ACC cell line H295R. AFF3 is located in nuclear speckles, which play an important role in RNA splicing. AFF3 overexpression in adrenocortical cells interferes with the organization and/or biogenesis of these nuclear speckles and alters the distribution of CDK9 and cyclin T1 such that they accumulate at the sites of AFF3/speckles. We demonstrate that AFF3 is a new target of Wnt/β-catenin pathway involved in ACC, acting on transcription and RNA splicing. PMID:26214578

Novel mutations and their functional and clinical relevance in myeloproliferative neoplasms: JAK2, MPL, TET2, ASXL1, CBL, IDH and IKZF1

PubMed Central

Tefferi, A

2010-01-01

Myeloproliferative neoplasms (MPNs) originate from genetically transformed hematopoietic stem cells that retain the capacity for multilineage differentiation and effective myelopoiesis. Beginning in early 2005, a number of novel mutations involving Janus kinase 2 (JAK2), Myeloproliferative Leukemia Virus (MPL), TET oncogene family member 2 (TET2), Additional Sex Combs-Like 1 (ASXL1), Casitas B-lineage lymphoma proto-oncogene (CBL), Isocitrate dehydrogenase (IDH) and IKAROS family zinc finger 1 (IKZF1) have been described in BCR-ABL1-negative MPNs. However, none of these mutations were MPN specific, displayed mutual exclusivity or could be traced back to a common ancestral clone. JAK2 and MPL mutations appear to exert a phenotype-modifying effect and are distinctly associated with polycythemia vera, essential thrombocythemia and primary myelofibrosis; the corresponding mutational frequencies are ∼99, 55 and 65% for JAK2 and 0, 3 and 10% for MPL mutations. The incidence of TET2, ASXL1, CBL, IDH or IKZF1 mutations in these disorders ranges from 0 to 17% these latter mutations are more common in chronic (TET2, ASXL1, CBL) or juvenile (CBL) myelomonocytic leukemias, mastocytosis (TET2), myelodysplastic syndromes (TET2, ASXL1) and secondary acute myeloid leukemia, including blast-phase MPN (IDH, ASXL1, IKZF1). The functional consequences of MPN-associated mutations include unregulated JAK-STAT (Janus kinase/signal transducer and activator of transcription) signaling, epigenetic modulation of transcription and abnormal accumulation of oncoproteins. However, it is not clear as to whether and how these abnormalities contribute to disease initiation, clonal evolution or blastic transformation. PMID:20428194

The impact of KRAS mutations on VEGF-A production and tumour vascular network

PubMed Central

2013-01-01

Background The malignant potential of tumour cells may be influenced by the molecular nature of KRAS mutations being codon 13 mutations less aggressive than codon 12 ones. Their metabolic profile is also different, with an increased anaerobic glycolytic metabolism in cells harbouring codon 12 KRAS mutations compared with cells containing codon 13 mutations. We hypothesized that this distinct metabolic behaviour could be associated with different HIF-1α expression and a distinct angiogenic profile. Methods Codon13 KRAS mutation (ASP13) or codon12 KRAS mutation (CYS12) NIH3T3 transfectants were analyzed in vitro and in vivo. Expression of HIF-1α, and VEGF-A was studied at RNA and protein levels. Regulation of VEGF-A promoter activity was assessed by means of luciferase assays using different plasmid constructs. Vascular network was assessed in tumors growing after subcutaneous inoculation. Non parametric statistics were used for analysis of results. Results Our results show that in normoxic conditions ASP13 transfectants exhibited less HIF-1α protein levels and activity than CYS12. In contrast, codon 13 transfectants exhibited higher VEGF-A mRNA and protein levels and enhanced VEGF-A promoter activity. These differences were due to a differential activation of Sp1/AP2 transcription elements of the VEGF-A promoter associated with increased ERKs signalling in ASP13 transfectants. Subcutaneous CYS12 tumours expressed less VEGF-A and showed a higher microvessel density (MVD) than ASP13 tumours. In contrast, prominent vessels were only observed in the latter. Conclusion Subtle changes in the molecular nature of KRAS oncogene activating mutations occurring in tumour cells have a major impact on the vascular strategy devised providing with new insights on the role of KRAS mutations on angiogenesis. PMID:23506169

Thyroid C-Cell Biology and Oncogenic Transformation

PubMed Central

Cote, Gilbert J.; Grubbs, Elizabeth G.; Hofmann, Marie-Claude

2017-01-01

The thyroid parafollicular cell, or commonly named “C-cell,” functions in serum calcium homeostasis. Elevations in serum calcium trigger release of calcitonin from the C-cell, which in turn functions to inhibit absorption of calcium by the intestine, resorption of bone by the osteoclast, and reabsorption of calcium by renal tubular cells. Oncogenic transformation of the thyroid C-cell is thought to progress through a hyperplastic process prior to malignancy with increasing levels of serum calcitonin serving as a biomarker for tumor burden. The discovery that Multiple Endocrine Neoplasia, type 2 is caused by activating mutations of the RET gene serves to highlight the RET-RAS-MAPK signaling pathway in both initiation and progression of medullary thyroid carcinoma. Thyroid C-cells are known to express RET at high levels relative to most cell types, therefore aberrant activation of this receptor is targeted primarily to the C-cell, providing one possible cause of tissue-specific oncogenesis. The role of RET signaling in normal C-cell function is unknown though calcitonin gene transcription appears to be sensitive to RET activation. Beyond RET the modeling of oncogenesis in animals and screening of human tumors for candidate gene mutations has uncovered mutation of RAS family members and inactivation of Rb1 regulatory pathway as potential mediators of C-cell transformation. A growing understanding of how RET interacts with these pathways, both in normal C-cell function and during oncogenic transformation will help in the development of novel molecular targeted therapies. PMID:26494382

Redox-Directed Cancer Therapeutics: Molecular Mechanisms and Opportunities

PubMed Central

2009-01-01

Abstract Redox dysregulation originating from metabolic alterations and dependence on mitogenic and survival signaling through reactive oxygen species represents a specific vulnerability of malignant cells that can be selectively targeted by redox chemotherapeutics. This review will present an update on drug discovery, target identification, and mechanisms of action of experimental redox chemotherapeutics with a focus on pro- and antioxidant redox modulators now in advanced phases of preclinal and clinical development. Recent research indicates that numerous oncogenes and tumor suppressor genes exert their functions in part through redox mechanisms amenable to pharmacological intervention by redox chemotherapeutics. The pleiotropic action of many redox chemotherapeutics that involves simultaneous modulation of multiple redox sensitive targets can overcome cancer cell drug resistance originating from redundancy of oncogenic signaling and rapid mutation. Moreover, some redox chemotherapeutics may function according to the concept of synthetic lethality (i.e., drug cytotoxicity is confined to cancer cells that display loss of function mutations in tumor suppressor genes or upregulation of oncogene expression). The impressive number of ongoing clinical trials that examine therapeutic performance of novel redox drugs in cancer patients demonstrates that redox chemotherapy has made the crucial transition from bench to bedside. Antioxid. Redox Signal. 11, 3013–3069. PMID:19496700

Genetic and pharmacological suppression of oncogenic mutations in RAS genes of yeast and humans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schafer, W.R.; Sterne, R.; Thorner, J.

1989-07-28

The activity of an oncoprotein and the secretion of a pheromone can be affected by an unusual protein modification. Specifically, posttranslational modification of yeast-a-factor and Ras protein requires an intermediate of the cholesterol biosynthetic pathway. This modification is apparently essential for biological activity. Studies of yeast mutants blocked in sterol biosynthesis demonstrated that the membrane association and biological activation of the yeast Ras2 protein require mevalonate, a precursor of sterols and other isoprenes such as farnesyl pyrophosphate. Furthermore, drugs that inhibit mevalonate biosynthesis blocked the in vivo action of oncogenic derivatives of human Ras protein in the Xenopus oocyte assay.more » The same drugs and mutations also prevented the posttranslational processing and secretion of yeast a-factor, a peptide that is farnesylated. Thus, the mevalonate requirement for Ras activation may indicate that attachment of a mevalonate-derived (isoprenoid) moiety to Ras proteins is necessary for membrane association and biological function. These observations establish a connection between the cholesterol biosynthetic pathway and transformation by the ras oncogene and offer a novel pharmacological approach to investigating, and possibly controlling, ras-mediated malignant transformations. 50 refs., 3 figs., 3 tabs.« less

Inhibition of Ras for cancer treatment: the search continues

PubMed Central

Baines, Antonio T.; Xu, Dapeng; Der, Channing J.

2012-01-01

Background The RAS oncogenes (HRAS, NRAS and KRAS) comprise the most frequently mutated class of oncogenes in human cancers (33%), stimulating intensive effort in developing anti-Ras inhibitors for cancer treatment. Discussion Despite intensive effort, to date no effective anti-Ras strategies have successfully made it to the clinic. We present an overview of past and ongoing strategies to inhibit oncogenic Ras in cancer. Conclusions Since approaches to directly target mutant Ras have not been successful, most efforts have focused on indirect approaches to block Ras membrane association or downstream effector signaling. While inhibitors of effector signaling are currently under clinical evaluation, genome-wide unbiased genetic screens have identified novel directions for future anti-Ras drug discovery. PMID:22004085

p53−/− synergizes with enhanced NrasG12D signaling to transform megakaryocyte-erythroid progenitors in acute myeloid leukemia

PubMed Central

Kong, Guangyao; Rajagopalan, Adhithi; Lu, Li; Song, Jingming; Hussaini, Mohamed; Zhang, Xinmin; Ranheim, Erik A.; Liu, Yangang; Wang, Jinyong; Gao, Xin; Chang, Yuan-I; Johnson, Kirby D.; Zhou, Yun; Yang, David; Bhatnagar, Bhavana; Lucas, David M.; Bresnick, Emery H.; Zhong, Xuehua; Padron, Eric

2017-01-01

Somatic mutations in TP53 and NRAS are associated with transformation of human chronic myeloid diseases to acute myeloid leukemia (AML). Here, we report that concurrent RAS pathway and TP53 mutations are identified in a subset of AML patients and confer an inferior overall survival. To further investigate the genetic interaction between p53 loss and endogenous NrasG12D/+ in AML, we generated conditional NrasG12D/+p53−/− mice. Consistent with the clinical data, recipient mice transplanted with NrasG12D/+p53−/− bone marrow cells rapidly develop a highly penetrant AML. We find that p53−/− cooperates with NrasG12D/+ to promote increased quiescence in megakaryocyte-erythroid progenitors (MEPs). NrasG12D/+p53−/− MEPs are transformed to self-renewing AML-initiating cells and are capable of inducing AML in serially transplanted recipients. RNA sequencing analysis revealed that transformed MEPs gain a partial hematopoietic stem cell signature and largely retain an MEP signature. Their distinct transcriptomes suggests a potential regulation by p53 loss. In addition, we show that during AML development, transformed MEPs acquire overexpression of oncogenic Nras, leading to hyperactivation of ERK1/2 signaling. Our results demonstrate that p53−/− synergizes with enhanced oncogenic Nras signaling to transform MEPs and drive AML development. This model may serve as a platform to test candidate therapeutics in this aggressive subset of AML. PMID:27815262

Oncogenic Gene Fusion FGFR3-TACC3 Is Regulated by Tyrosine Phosphorylation.

PubMed

Nelson, Katelyn N; Meyer, April N; Siari, Asma; Campos, Alexandre R; Motamedchaboki, Khatereh; Donoghue, Daniel J

2016-05-01

Fibroblast growth factor receptors (FGFR) are critical for cell proliferation and differentiation. Mutation and/or translocation of FGFRs lead to aberrant signaling that often results in developmental syndromes or cancer growth. As sequencing of human tumors becomes more frequent, so does the detection of FGFR translocations and fusion proteins. The research conducted in this article examines a frequently identified fusion protein between FGFR3 and transforming acidic coiled-coil containing protein 3 (TACC3), frequently identified in glioblastoma, lung cancer, bladder cancer, oral cancer, head and neck squamous cell carcinoma, gallbladder cancer, and cervical cancer. Using titanium dioxide-based phosphopeptide enrichment (TiO2)-liquid chromatography (LC)-high mass accuracy tandem mass spectrometry (MS/MS), it was demonstrated that the fused coiled-coil TACC3 domain results in constitutive phosphorylation of key activating FGFR3 tyrosine residues. The presence of the TACC coiled-coil domain leads to increased and altered levels of FGFR3 activation, fusion protein phosphorylation, MAPK pathway activation, nuclear localization, cellular transformation, and IL3-independent proliferation. Introduction of K508R FGFR3 kinase-dead mutation abrogates these effects, except for nuclear localization which is due solely to the TACC3 domain. These results demonstrate that FGFR3 kinase activity is essential for the oncogenic effects of the FGFR3-TACC3 fusion protein and could serve as a therapeutic target, but that phosphorylated tyrosine residues within the TACC3-derived portion are not critical for activity. Mol Cancer Res; 14(5); 458-69. ©2016 AACR. ©2016 American Association for Cancer Research.

Mutations in the Polybasic Juxtamembrane Sequence of Both Plasma Membrane- and Endoplasmic Reticulum-localized Epidermal Growth Factor Receptors Confer Ligand-independent Cell Transformation*

PubMed Central

Bryant, Kirsten L.; Antonyak, Marc A.; Cerione, Richard A.; Baird, Barbara; Holowka, David

2013-01-01

Deregulation of ErbB receptor-tyrosine kinases is a hallmark of many human cancers. Conserved in the ErbB family is a cluster of basic amino acid residues in the cytoplasmic juxtamembrane region. We found that charge-silencing mutagenesis within this juxtamembrane region of the epidermal growth factor receptor (EGFR) results in the generation of a mutant receptor (EGFR Mut R1-6) that spontaneously transforms NIH 3T3 cells in a ligand-independent manner. A similar mutant with one additional basic residue, EGFR Mut R1-5, fails to exhibit ligand-independent transformation. The capacity of EGFR Mut R1-6 to mediate this transformation is maintained when this mutant is retained in the endoplasmic reticulum via a single point mutation, L393H, which we describe. We show that EGFR Mut R1-6 with or without L393H exhibits enhanced basal tyrosine phosphorylation when ectopically expressed, and the ligand-independent transforming activity of EGFR Mut R1-6 is sensitive to inhibition of EGFR kinase activity and is particularly dependent on PI3K and mTOR activity. Similar to EGFR Mut R1-6/L393H in NIH 3T3 cells, EGFR variant type III, a highly oncogenic mutant form of EGFR linked to human brain cancers, confers transforming activity while it is wholly endoplasmic reticulum-retained in U87 cells. Our findings highlight the importance of the polybasic juxtamembrane sequence in regulating the oncogenic potential of EGFR signaling. PMID:24142702

A Robust Error Model for iTRAQ Quantification Reveals Divergent Signaling between Oncogenic FLT3 Mutants in Acute Myeloid Leukemia*

PubMed Central

Zhang, Yi; Askenazi, Manor; Jiang, Jingrui; Luckey, C. John; Griffin, James D.; Marto, Jarrod A.

2010-01-01

The FLT3 receptor tyrosine kinase plays an important role in normal hematopoietic development and leukemogenesis. Point mutations within the activation loop and in-frame tandem duplications of the juxtamembrane domain represent the most frequent molecular abnormalities observed in acute myeloid leukemia. Interestingly these gain-of-function mutations correlate with different clinical outcomes, suggesting that signals from constitutive FLT3 mutants activate different downstream targets. In principle, mass spectrometry offers a powerful means to quantify protein phosphorylation and identify signaling events associated with constitutively active kinases or other oncogenic events. However, regulation of individual phosphorylation sites presents a challenging case for proteomics studies whereby quantification is based on individual peptides rather than an average across different peptides derived from the same protein. Here we describe a robust experimental framework and associated error model for iTRAQ-based quantification on an Orbitrap mass spectrometer that relates variance of peptide ratios to mass spectral peak height and provides for assignment of p value, q value, and confidence interval to every peptide identification, all based on routine measurements, obviating the need for detailed characterization of individual ion peaks. Moreover, we demonstrate that our model is stable over time and can be applied in a manner directly analogous to ubiquitously used external mass calibration routines. Application of our error model to quantitative proteomics data for FLT3 signaling provides evidence that phosphorylation of tyrosine phosphatase SHP1 abrogates the transformative potential, but not overall kinase activity, of FLT3-D835Y in acute myeloid leukemia. PMID:20019052

Targeting protein-trafficking pathways alters melanoma treatment sensitivity

PubMed Central

Huang, Zhi-ming; Chinen, Milka; Chang, Philip J.; Xie, Tong; Zhong, Lily; Demetriou, Stephanie; Patel, Mira P.; Scherzer, Rebecca; Sviderskaya, Elena V.; Bennett, Dorothy C.; Millhauser, Glenn L.; Oh, Dennis H.; Cleaver, James E.; Wei, Maria L.

2012-01-01

Protein-trafficking pathways are targeted here in human melanoma cells using methods independent of oncogene mutational status, and the ability to up-regulate and down-regulate tumor treatment sensitivity is demonstrated. Sensitivity of melanoma cells to cis-diaminedichloroplatinum II (cDDP, cis-platin), carboplatin, dacarbazine, or temozolomide together with velaparib, an inhibitor of poly (ADP ribose) polymerase 1, is increased by up to 10-fold by targeting genes that regulate both protein trafficking and the formation of melanosomes, intracellular organelles unique to melanocytes and melanoma cells. Melanoma cells depleted of either of the protein-trafficking regulators vacuolar protein sorting 33A protein (VPS33A) or cappuccino protein (CNO) have increased nuclear localization of cDDP, increased nuclear DNA damage by platination, and increased apoptosis, resulting in increased treatment sensitivity. Depleted cells also exhibit a decreased proportion of intracellular, mature melanosomes compared with undepleted cells. Modulation of protein trafficking via cell-surface signaling by binding the melanocortin 1 receptor with the antagonist agouti-signaling protein decreased the proportion of mature melanosomes formed and increased cDDP sensitivity, whereas receptor binding with the agonist melanocyte-stimulating hormone resulted in an increased proportion of mature melanosomes formed and in decreased sensitivity (i.e., increased resistance) to cDDP. Mutation of the protein-trafficking gene Hps6, known to impair the formation of mature melanosomes, also increased cDDP sensitivity. Together, these results indicate that targeting protein-trafficking molecules markedly increases melanoma treatment sensitivity and influences the degree of melanosomes available for sequestration of therapeutic agents. PMID:22203954

EVI1 carboxy-terminal phosphorylation is ATM-mediated and sustains transcriptional modulation and self-renewal via enhanced CtBP1 association.

PubMed

Paredes, Roberto; Schneider, Marion; Stevens, Adam; White, Daniel J; Williamson, Andrew Jk; Muter, Joanne; Pearson, Stella; Kelly, James R; Connors, Kathleen; Wiseman, Daniel H; Chadwick, John A; Löffler, Harald; Teng, Hsiang Ying; Lovell, Simon; Unwin, Richard; van de Vrugt, Henri J; Smith, Helen; Kustikova, Olga; Schambach, Axel; Somervaille, Tim C P; Pierce, Andrew; Whetton, Anthony D; Meyer, Stefan

2018-06-25

The transcriptional regulator EVI1 has an essential role in early hematopoiesis and development. However, aberrantly high expression of EVI1 has potent oncogenic properties and confers poor prognosis and chemo-resistance in leukemia and solid tumors. To investigate to what extent EVI1 function might be regulated by post-translational modifications we carried out mass spectrometry- and antibody-based analyses and uncovered an ATM-mediated double phosphorylation of EVI1 at the carboxy-terminal S858/S860 SQS motif. In the presence of genotoxic stress EVI1-WT (SQS), but not site mutated EVI1-AQA was able to maintain transcriptional patterns and transformation potency, while under standard conditions carboxy-terminal mutation had no effect. Maintenance of hematopoietic progenitor cell clonogenic potential was profoundly impaired with EVI1-AQA compared with EVI1-WT, in particular in the presence of genotoxic stress. Exploring mechanistic events underlying these observations, we showed that after genotoxic stress EVI1-WT, but not EVI1-AQA increased its level of association with its functionally essential interaction partner CtBP1, implying a role for ATM in regulating EVI1 protein interactions via phosphorylation. This aspect of EVI1 regulation is therapeutically relevant, as chemotherapy-induced genotoxicity might detrimentally sustain EVI1 function via stress response mediated phosphorylation, and ATM-inhibition might be of specific targeted benefit in EVI1-overexpressing malignancies.

Factors of transforming growth factor beta signalling are co-regulated in human hepatocellular carcinoma.

PubMed

Longerich, Thomas; Breuhahn, Kai; Odenthal, Margarete; Petmecky, Katharina; Schirmacher, Peter

2004-12-01

Transforming growth factor beta (TGFbeta) is a central mitoinhibitory factor for epithelial cells, and alterations of TGFbeta signalling have been demonstrated in many different human cancers. We have analysed human hepatocellular carcinomas (HCCs) for potential pro-tumourigenic alterations in regard to expression of Smad4 and mutations and expression changes of the pro-oncogenic transcriptional co-repressors Ski and SnoN, as well as mRNA levels of matrix metalloproteinase-2 (MMP2), which is transcriptionally regulated by TGFbeta. Smad4 mRNA was detected in all HCCs; while, using immunohistology, loss of Smad4 expression was found in 10% of HCCs. Neither mutations in the transformation-relevant sequences nor significant pro-tumourigenic expression changes of the Ski and SnoN genes were detected. In HCC cell lines, expression of both genes was regulated, potentially involving phosphorylation. Ski showed a distinct nuclear speckled pattern, indicating recruitment to active transcription complexes. MMP2 mRNA levels were increased in 19% of HCCs, whereas MMP2 mRNA was not detectable in HCC cell lines, suggesting that MMP2 was derived only from tumour stroma cells. Transcript levels of Smad4, Ski, SnoN and MMP2 correlated well. These data argue against a significant role of Ski and SnoN in human hepatocarcinogenesis and suggest that, in the majority of HCCs, the analysed factors are co-regulated by an upstream mechanism, potentially by TGFbeta itself.

CBL family E3 ubiquitin ligases control JAK2 ubiquitination and stability in hematopoietic stem cells and myeloid malignancies

PubMed Central

Lv, Kaosheng; Jiang, Jing; Donaghy, Ryan; Riling, Christopher R.; Cheng, Ying; Chandra, Vemika; Rozenova, Krasimira; An, Wei; Mohapatra, Bhopal C.; Goetz, Benjamin T.; Pillai, Vinodh; Han, Xu; Todd, Emily A.; Jeschke, Grace R.; Langdon, Wallace Y.; Kumar, Suresh; Hexner, Elizabeth O.

2017-01-01

Janus kinase 2 (JAK2) is a central kinase in hematopoietic stem/progenitor cells (HSPCs), and its uncontrolled activation is a prominent oncogenic driver of hematopoietic neoplasms. However, molecular mechanisms underlying the regulation of JAK2 have remained elusive. Here we report that the Casitas B-cell lymphoma (CBL) family E3 ubiquitin ligases down-regulate JAK2 stability and signaling via the adaptor protein LNK/SH2B3. We demonstrated that depletion of CBL/CBL-B or LNK abrogated JAK2 ubiquitination, extended JAK2 half-life, and enhanced JAK2 signaling and cell growth in human cell lines as well as primary murine HSPCs. Built on these findings, we showed that JAK inhibitor (JAKi) significantly reduced aberrant HSPCs and mitigated leukemia development in a mouse model of aggressive myeloid leukemia driven by loss of Cbl and Cbl-b. Importantly, primary human CBL mutated (CBLmut) leukemias exhibited increased JAK2 protein levels and signaling and were hypersensitive to JAKi. Loss-of-function mutations in CBL E3 ubiquitin ligases are found in a wide range of myeloid malignancies, which are diseases without effective treatment options. Hence, our studies reveal a novel signaling axis that regulates JAK2 in normal and malignant HSPCs and suggest new therapeutic strategies for treating CBLmut myeloid malignancies. PMID:28611190

Transposon mutagenesis identifies chromatin modifiers cooperating with Ras in thyroid tumorigenesis and detects ATXN7 as a cancer gene.

PubMed

Montero-Conde, Cristina; Leandro-Garcia, Luis J; Chen, Xu; Oler, Gisele; Ruiz-Llorente, Sergio; Ryder, Mabel; Landa, Iñigo; Sanchez-Vega, Francisco; La, Konnor; Ghossein, Ronald A; Bajorin, Dean F; Knauf, Jeffrey A; Riordan, Jesse D; Dupuy, Adam J; Fagin, James A

2017-06-20

Oncogenic RAS mutations are present in 15-30% of thyroid carcinomas. Endogenous expression of mutant Ras is insufficient to initiate thyroid tumorigenesis in murine models, indicating that additional genetic alterations are required. We used Sleeping Beauty (SB) transposon mutagenesis to identify events that cooperate with Hras G12V in thyroid tumor development. Random genomic integration of SB transposons primarily generated loss-of-function events that significantly increased thyroid tumor penetrance in Tpo-Cre/homozygous FR-Hras G12V mice. The thyroid tumors closely phenocopied the histological features of human RAS-driven, poorly differentiated thyroid cancers. Characterization of transposon insertion sites in the SB-induced tumors identified 45 recurrently mutated candidate cancer genes. These mutation profiles were remarkably concordant with mutated cancer genes identified in a large series of human poorly differentiated and anaplastic thyroid cancers screened by next-generation sequencing using the MSK-IMPACT panel of cancer genes, which we modified to include all SB candidates. The disrupted genes primarily clustered in chromatin remodeling functional nodes and in the PI3K pathway. ATXN7 , a component of a multiprotein complex with histone acetylase activity, scored as a significant SB hit. It was recurrently mutated in advanced human cancers and significantly co-occurred with RAS or NF1 mutations. Expression of ATXN7 mutants cooperated with oncogenic RAS to induce thyroid cell proliferation, pointing to ATXN7 as a previously unrecognized cancer gene.

Transposon mutagenesis identifies chromatin modifiers cooperating with Ras in thyroid tumorigenesis and detects ATXN7 as a cancer gene

PubMed Central

Montero-Conde, Cristina; Leandro-Garcia, Luis J.; Chen, Xu; Oler, Gisele; Ruiz-Llorente, Sergio; Ryder, Mabel; Landa, Iñigo; Sanchez-Vega, Francisco; La, Konnor; Ghossein, Ronald A.; Bajorin, Dean F.; Knauf, Jeffrey A.; Riordan, Jesse D.; Dupuy, Adam J.; Fagin, James A.

2017-01-01

Oncogenic RAS mutations are present in 15–30% of thyroid carcinomas. Endogenous expression of mutant Ras is insufficient to initiate thyroid tumorigenesis in murine models, indicating that additional genetic alterations are required. We used Sleeping Beauty (SB) transposon mutagenesis to identify events that cooperate with HrasG12V in thyroid tumor development. Random genomic integration of SB transposons primarily generated loss-of-function events that significantly increased thyroid tumor penetrance in Tpo-Cre/homozygous FR-HrasG12V mice. The thyroid tumors closely phenocopied the histological features of human RAS-driven, poorly differentiated thyroid cancers. Characterization of transposon insertion sites in the SB-induced tumors identified 45 recurrently mutated candidate cancer genes. These mutation profiles were remarkably concordant with mutated cancer genes identified in a large series of human poorly differentiated and anaplastic thyroid cancers screened by next-generation sequencing using the MSK-IMPACT panel of cancer genes, which we modified to include all SB candidates. The disrupted genes primarily clustered in chromatin remodeling functional nodes and in the PI3K pathway. ATXN7, a component of a multiprotein complex with histone acetylase activity, scored as a significant SB hit. It was recurrently mutated in advanced human cancers and significantly co-occurred with RAS or NF1 mutations. Expression of ATXN7 mutants cooperated with oncogenic RAS to induce thyroid cell proliferation, pointing to ATXN7 as a previously unrecognized cancer gene. PMID:28584132

Differential Effects of CSF-1R D802V and KIT D816V Homologous Mutations on Receptor Tertiary Structure and Allosteric Communication

PubMed Central

Da Silva Figueiredo Celestino Gomes, Priscila; Panel, Nicolas; Laine, Elodie; Pascutti, Pedro Geraldo; Solary, Eric; Tchertanov, Luba

2014-01-01

The colony stimulating factor-1 receptor (CSF-1R) and the stem cell factor receptor KIT, type III receptor tyrosine kinases (RTKs), are important mediators of signal transduction. The normal functions of these receptors can be compromised by gain-of-function mutations associated with different physiopatological impacts. Whereas KIT D816V/H mutation is a well-characterized oncogenic event and principal cause of systemic mastocytosis, the homologous CSF-1R D802V has not been identified in human cancers. The KIT D816V oncogenic mutation triggers resistance to the RTK inhibitor Imatinib used as first line treatment against chronic myeloid leukemia and gastrointestinal tumors. CSF-1R is also sensitive to Imatinib and this sensitivity is altered by mutation D802V. Previous in silico characterization of the D816V mutation in KIT evidenced that the mutation caused a structure reorganization of the juxtamembrane region (JMR) and facilitated its departure from the kinase domain (KD). In this study, we showed that the equivalent CSF-1R D802V mutation does not promote such structural effects on the JMR despite of a reduction on some key H-bonds interactions controlling the JMR binding to the KD. In addition, this mutation disrupts the allosteric communication between two essential regulatory fragments of the receptors, the JMR and the A-loop. Nevertheless, the mutation-induced shift towards an active conformation observed in KIT D816V is not observed in CSF-1R D802V. The distinct impact of equivalent mutation in two homologous RTKs could be associated with the sequence difference between both receptors in the native form, particularly in the JMR region. A local mutation-induced perturbation on the A-loop structure observed in both receptors indicates the stabilization of an inactive non-inhibited form, which Imatinib cannot bind. PMID:24828813

The driver and passenger effects of isocitrate dehydrogenase 1 and 2 mutations in oncogenesis and survival prolongation.

PubMed

Molenaar, Remco J; Radivoyevitch, Tomas; Maciejewski, Jaroslaw P; van Noorden, Cornelis J F; Bleeker, Fonnet E

2014-12-01

Mutations in isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are key events in the development of glioma, acute myeloid leukemia (AML), chondrosarcoma, intrahepatic cholangiocarcinoma (ICC), and angioimmunoblastic T-cell lymphoma. They also cause D-2-hydroxyglutaric aciduria and Ollier and Maffucci syndromes. IDH1/2 mutations are associated with prolonged survival in glioma and in ICC, but not in AML. The reason for this is unknown. In their wild-type forms, IDH1 and IDH2 convert isocitrate and NADP(+) to α-ketoglutarate (αKG) and NADPH. Missense mutations in the active sites of these enzymes induce a neo-enzymatic reaction wherein NADPH reduces αKG to D-2-hydroxyglutarate (D-2HG). The resulting D-2HG accumulation leads to hypoxia-inducible factor 1α degradation, and changes in epigenetics and extracellular matrix homeostasis. Such mutations also imply less NADPH production capacity. Each of these effects could play a role in cancer formation. Here, we provide an overview of the literature and discuss which downstream molecular effects are likely to be the drivers of the oncogenic and survival-prolonging properties of IDH1/2 mutations. We discuss interactions between mutant IDH1/2 inhibitors and conventional therapies. Understanding of the biochemical consequences of IDH1/2 mutations in oncogenesis and survival prolongation will yield valuable information for rational therapy design: it will tell us which oncogenic processes should be blocked and which "survivalogenic" effects should be retained. Copyright © 2014 Elsevier B.V. All rights reserved.

Double KRAS and BRAF Mutations in Surgically Treated Colorectal Cancer Liver Metastases: An International, Multi-institutional Case Series.

PubMed

Deshwar, Amar; Margonis, Georgios Antonios; Andreatos, Nikolaos; Barbon, Carlotta; Wang, Jaeyun; Buettner, Stefan; Wagner, Doris; Sasaki, Kazunari; Beer, Andrea; Løes, Inger Marie; Pikoulis, Emmanouil; Damaskos, Christos; Garmpis, Nikolaos; Kamphues, Karsten; He, Jin; Kaczirek, Klaus; Poultsides, George; Lønning, Per Eystein; Mischinger, Hans Joerg; Aucejo, Federico N; Kreis, Martin E; Wolfgang, Christopher L; Weiss, Matthew J

2018-05-01

While previously believed to be mutually exclusive, concomitant mutation of Kirsten rat sarcoma viral oncogene homolog (KRAS)- and V-raf murine sarcoma b-viral oncogene homolog B1 (BRAF)-mutated colorectal carcinoma (CRC), has been described in rare instances and been associated with advanced-stage disease. The present case series is the first to report on the implications of concurrent KRAS/BRAF mutations among surgically treated patients, and the largest set of patients with surgically treated colorectal liver metastasis (CRLM) and data on KRAS/BRAF mutational status thus far described. We present cases from an international, multi-institutional cohort of patients that underwent hepatic resection for CRLM between 2000-2015 at seven tertiary centers. The incidence of KRAS/BRAF mutation in patients with CRLM was 0.5% (4/820). Of these cases, patient 1 (T2N1 primary, G13D/V600E), patient 2 (T3N1 primary, G12V/V600E) and patient 3 (T4N2 primary, G13D/D594N) succumbed to their disease within 485, 236 and 79 days respectively, post-hepatic resection. Patient 4 (T4 primary, G12S/G469S) was alive 416 days after hepatic resection. The present case series suggests that the incidence of concomitant KRAS/BRAF mutations in surgical cohorts may be higher than previously hypothesized, and associated with more variable survival outcomes than expected. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

A role for the epidermal growth factor receptor signaling in development of intestinal serrated polyps in mice and humans.

PubMed

Bongers, Gerold; Muniz, Luciana R; Pacer, Michelle E; Iuga, Alina C; Thirunarayanan, Nanthakumar; Slinger, Erik; Smit, Martine J; Reddy, E Premkumar; Mayer, Lloyd; Furtado, Glaucia C; Harpaz, Noam; Lira, Sergio A

2012-09-01

Epithelial cancers can be initiated by activating mutations in components of the mitogen-activated protein kinase signaling pathway such as v-raf murine sarcoma viral oncogene homolog B1 (BRAF), v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), or epidermal growth factor receptor (EGFR). Human intestinal serrated polyps are a heterogeneous group of benign lesions, but some progress to colorectal cancer. Tumors that arise from these polyps frequently contain activating mutations in BRAF or KRAS, but little is known about the role of EGFR activation in their development. Polyp samples were obtained from adults during screening colonoscopies at Mount Sinai Hospital in New York. We measured levels of EGFR protein and phosphorylation in human serrated polyps by immunohistochemical and immunoblot analyses. We generated transgenic mice that express the ligand for EGFR, Heparin-binding EGF-like growth factor (HB-EGF), in the intestine. EGFR and the extracellular-regulated kinases (ERK)1/2 were phosphorylated in serrated areas of human hyperplastic polyps (HPPs), sessile serrated adenomas, and traditional serrated adenomas. EGFR and ERK1/2 were phosphorylated in the absence of KRAS or BRAF activating mutations in a subset of HPP. Transgenic expression of the EGFR ligand HB-EGF in the intestines of mice promoted development of small cecal serrated polyps. Mice that expressed a combination of HB-EGF and US28 (a constitutively active, G-protein-coupled receptor that increases processing of HB-EGF from the membrane) rapidly developed large cecal serrated polyps. These polyps were similar to HPPs and had increased phosphorylation of EGFR and ERK1/2 within the serrated epithelium. Administration of pharmacologic inhibitors of EGFR or MAPK to these transgenic mice significantly reduced polyp development. Activation of EGFR signaling in the intestine of mice promotes development of serrated polyps. EGFR signaling also is activated in human HPPs, sessile serrated adenomas, and traditional serrated adenomas. Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.

Prediction of Oncogenic Interactions and Cancer-Related Signaling Networks Based on Network Topology

PubMed Central

Acencio, Marcio Luis; Bovolenta, Luiz Augusto; Camilo, Esther; Lemke, Ney

2013-01-01

Cancer has been increasingly recognized as a systems biology disease since many investigators have demonstrated that this malignant phenotype emerges from abnormal protein-protein, regulatory and metabolic interactions induced by simultaneous structural and regulatory changes in multiple genes and pathways. Therefore, the identification of oncogenic interactions and cancer-related signaling networks is crucial for better understanding cancer. As experimental techniques for determining such interactions and signaling networks are labor-intensive and time-consuming, the development of a computational approach capable to accomplish this task would be of great value. For this purpose, we present here a novel computational approach based on network topology and machine learning capable to predict oncogenic interactions and extract relevant cancer-related signaling subnetworks from an integrated network of human genes interactions (INHGI). This approach, called graph2sig, is twofold: first, it assigns oncogenic scores to all interactions in the INHGI and then these oncogenic scores are used as edge weights to extract oncogenic signaling subnetworks from INHGI. Regarding the prediction of oncogenic interactions, we showed that graph2sig is able to recover 89% of known oncogenic interactions with a precision of 77%. Moreover, the interactions that received high oncogenic scores are enriched in genes for which mutations have been causally implicated in cancer. We also demonstrated that graph2sig is potentially useful in extracting oncogenic signaling subnetworks: more than 80% of constructed subnetworks contain more than 50% of original interactions in their corresponding oncogenic linear pathways present in the KEGG PATHWAY database. In addition, the potential oncogenic signaling subnetworks discovered by graph2sig are supported by experimental evidence. Taken together, these results suggest that graph2sig can be a useful tool for investigators involved in cancer research interested in detecting signaling networks most prone to contribute with the emergence of malignant phenotype. PMID:24204854

The human T-cell leukemia virus type-1 p30II protein activates p53 and induces the TIGAR and suppresses oncogene-induced oxidative stress during viral carcinogenesis.

PubMed

Romeo, Megan; Hutchison, Tetiana; Malu, Aditi; White, Averi; Kim, Janice; Gardner, Rachel; Smith, Katie; Nelson, Katherine; Bergeson, Rachel; McKee, Ryan; Harrod, Carolyn; Ratner, Lee; Lüscher, Bernhard; Martinez, Ernest; Harrod, Robert

2018-05-01

In normal cells, aberrant oncogene expression leads to the accumulation of cytotoxic metabolites, including reactive oxygen species (ROS), which can cause oxidative DNA-damage and apoptosis as an intrinsic barrier against neoplastic disease. The c-Myc oncoprotein is overexpressed in many lymphoid cancers due to c-myc gene amplification and/or 8q24 chromosomal translocations. Intriguingly, p53 is a downstream target of c-Myc and hematological malignancies, such as adult T-cell leukemia/lymphoma (ATL), frequently contain wildtype p53 and c-Myc overexpression. We therefore hypothesized that p53-regulated pro-survival signals may thwart the cell's metabolic anticancer defenses to support oncogene-activation in lymphoid cancers. Here we show that the Tp53-induced glycolysis and apoptosis regulator (TIGAR) promotes c-myc oncogene-activation by the human T-cell leukemia virus type-1 (HTLV-1) latency-maintenance factor p30 II , associated with c-Myc deregulation in ATL clinical isolates. TIGAR prevents the intracellular accumulation of c-Myc-induced ROS and inhibits oncogene-induced cellular senescence in ATL, acute lymphoblastic leukemia, and multiple myeloma cells with elevated c-Myc expression. Our results allude to a pivotal role for p53-regulated antioxidant signals as mediators of c-Myc oncogenic functions in viral and non-viral lymphoid tumors. Copyright © 2018 Elsevier Inc. All rights reserved.

Next Generation MUT-MAP, a High-Sensitivity High-Throughput Microfluidics Chip-Based Mutation Analysis Panel

PubMed Central

Patel, Rajesh; Tsan, Alison; Sumiyoshi, Teiko; Fu, Ling; Desai, Rupal; Schoenbrunner, Nancy; Myers, Thomas W.; Bauer, Keith; Smith, Edward; Raja, Rajiv

2014-01-01

Molecular profiling of tumor tissue to detect alterations, such as oncogenic mutations, plays a vital role in determining treatment options in oncology. Hence, there is an increasing need for a robust and high-throughput technology to detect oncogenic hotspot mutations. Although commercial assays are available to detect genetic alterations in single genes, only a limited amount of tissue is often available from patients, requiring multiplexing to allow for simultaneous detection of mutations in many genes using low DNA input. Even though next-generation sequencing (NGS) platforms provide powerful tools for this purpose, they face challenges such as high cost, large DNA input requirement, complex data analysis, and long turnaround times, limiting their use in clinical settings. We report the development of the next generation mutation multi-analyte panel (MUT-MAP), a high-throughput microfluidic, panel for detecting 120 somatic mutations across eleven genes of therapeutic interest (AKT1, BRAF, EGFR, FGFR3, FLT3, HRAS, KIT, KRAS, MET, NRAS, and PIK3CA) using allele-specific PCR (AS-PCR) and Taqman technology. This mutation panel requires as little as 2 ng of high quality DNA from fresh frozen or 100 ng of DNA from formalin-fixed paraffin-embedded (FFPE) tissues. Mutation calls, including an automated data analysis process, have been implemented to run 88 samples per day. Validation of this platform using plasmids showed robust signal and low cross-reactivity in all of the newly added assays and mutation calls in cell line samples were found to be consistent with the Catalogue of Somatic Mutations in Cancer (COSMIC) database allowing for direct comparison of our platform to Sanger sequencing. High correlation with NGS when compared to the SuraSeq500 panel run on the Ion Torrent platform in a FFPE dilution experiment showed assay sensitivity down to 0.45%. This multiplexed mutation panel is a valuable tool for high-throughput biomarker discovery in personalized medicine and cancer drug development. PMID:24658394

Something Old, Something New, Something Borrowed, Something Fused: Novel EGFR Rearrangements in Lung Adenocarcinomas.

PubMed

Paik, Paul K

2016-06-01

Mutations in EGFR stand as the archetype for somatic alterations that lead to oncogene addiction and that predict for response to targeted therapies. In this issue of Cancer Discovery, Konduri and colleagues report on a pair of novel oncogenic and actionable EGFR fusion events in a series of patients with lung adenocarcinomas, casting new light on this model gene. Cancer Discov; 6(6); 574-5. ©2016 AACRSee related article by Konduri et al., p. 601. ©2016 American Association for Cancer Research.

Phosphatidylinositol Phosphate 5-Kinase Iγi2 in Association with Src Controls Anchorage-independent Growth of Tumor Cells*

PubMed Central

Thapa, Narendra; Choi, Suyong; Hedman, Andrew; Tan, Xiaojun; Anderson, Richard A.

2013-01-01

A fundamental property of tumor cells is to defy anoikis, cell death caused by a lack of cell-matrix interaction, and grow in an anchorage-independent manner. How tumor cells organize signaling molecules at the plasma membrane to sustain oncogenic signals in the absence of cell-matrix interactions remains poorly understood. Here, we describe a role for phosphatidylinositol 4-phosphate 5-kinase (PIPK) Iγi2 in controlling anchorage-independent growth of tumor cells in coordination with the proto-oncogene Src. PIPKIγi2 regulated Src activation downstream of growth factor receptors and integrins. PIPKIγi2 directly interacted with the C-terminal tail of Src and regulated its subcellular localization in concert with talin, a cytoskeletal protein targeted to focal adhesions. Co-expression of PIPKIγi2 and Src synergistically induced the anchorage-independent growth of nonmalignant cells. This study uncovers a novel mechanism where a phosphoinositide-synthesizing enzyme, PIPKIγi2, functions with the proto-oncogene Src, to regulate oncogenic signaling. PMID:24151076

A Pan-Cancer Proteogenomic Atlas of PI3K/AKT/mTOR Pathway Alterations | Office of Cancer Genomics

Cancer.gov

Molecular alterations involving the PI3K/Akt/mTOR pathway (including mutation, copy number, protein, or RNA) were examined across 11,219 human cancers representing 32 major types. Within specific mutated genes, frequency, mutation hotspot residues, in silico predictions, and functional assays were all informative in distinguishing the subset of genetic variants more likely to have functional relevance. Multiple oncogenic pathways including PI3K/Akt/mTOR converged on similar sets of downstream transcriptional targets.

Multiproteomic and Transcriptomic Analysis of Oncogenic β-Catenin Molecular Networks.

PubMed

Ewing, Rob M; Song, Jing; Gokulrangan, Giridharan; Bai, Sheldon; Bowler, Emily H; Bolton, Rachel; Skipp, Paul; Wang, Yihua; Wang, Zhenghe

2018-06-01

The dysregulation of Wnt signaling is a frequent occurrence in many different cancers. Oncogenic mutations of CTNNB1/β-catenin, the key nuclear effector of canonical Wnt signaling, lead to the accumulation and stabilization of β-catenin protein with diverse effects in cancer cells. Although the transcriptional response to Wnt/β-catenin signaling activation has been widely studied, an integrated understanding of the effects of oncogenic β-catenin on molecular networks is lacking. We used affinity-purification mass spectrometry (AP-MS), label-free liquid chromatography-tandem mass spectrometry, and RNA-Seq to compare protein-protein interactions, protein expression, and gene expression in colorectal cancer cells expressing mutant (oncogenic) or wild-type β-catenin. We generate an integrated molecular network and use it to identify novel protein modules that are associated with mutant or wild-type β-catenin. We identify a DNA methyltransferase I associated subnetwork that is enriched in cells with mutant β-catenin and a subnetwork enriched in wild-type cells associated with the CDKN2A tumor suppressor, linking these processes to the transformation of colorectal cancer cells through oncogenic β-catenin signaling. In summary, multiomics analysis of a defined colorectal cancer cell model provides a significantly more comprehensive identification of functional molecular networks associated with oncogenic β-catenin signaling.

Overproduction of v-Myc in the nucleus and its excess over Max are not required for avian fibroblast transformation.

PubMed Central

Tikhonenko, A T; Hartman, A R; Linial, M L

1993-01-01

The cellular proto-oncogene c-myc can acquire transforming potential by a number of different means, including retroviral transduction. The transduced allele generally contains point mutations relative to c-myc and is overexpressed in infected cells, usually as a v-Gag-Myc fusion protein. Upon synthesis, v-Gag-Myc enters the nucleus, forms complexes with its heterodimeric partner Max, and in this complex binds to DNA in a sequence-specific manner. To delineate the role for each of these events in fibroblast transformation, we introduced several mutations into the myc gene of the avian retrovirus MC29. We observed that Gag-Myc with a mutated nuclear localization signal is confined predominantly in the cytoplasm and only about 5% of the protein could be detected in the nucleus (less than the amount of endogenous c-Myc). Consequently, only a small fraction of Max is associated with Myc. However, cells infected with this mutant exhibit a completely transformed phenotype in vitro, suggesting that production of enough v-Gag-Myc to tie up all cellular Max is not needed for transformation. While the nuclear localization signal is dispensable for transformation, minimal changes in the v-Gag-Myc DNA-binding domain completely abolish its transforming potential, consistent with a role of Myc as a transcriptional regulator. One of its potential targets might be the endogenous c-myc, which is repressed in wild-type MC29-infected cells. Our experiments with MC29 mutants demonstrate that c-myc down-regulation depends on the integrity of the v-Myc DNA-binding domain and occurs at the RNA level. Hence, it is conceivable that v-Gag-Myc, either directly or circuitously, regulates c-myc transcription. Images PMID:8497274

Absence of ras-gene hot-spot mutations in canine fibrosarcomas and melanomas.

PubMed

Murua Escobar, Hugo; Günther, Kathrin; Richter, Andreas; Soller, Jan T; Winkler, Susanne; Nolte, Ingo; Bullerdiek, Jörn

2004-01-01

Point mutations within ras proto-oncogenes, particularly within the mutational hot-spot codons 12, 13 and 61, are frequently detected in human malignancies and in different types of experimentally-induced tumours in animals. So far little is known about ras mutations in naturally occurring canine fibrosarcomas or K-ras mutations in canine melanomas. To elucidate whether ras mutations exist in these naturally occurring tumours in dogs, in the present study we screened 13 canine fibrosarcomas, 2 feline fibrosarcomas and 11 canine melanomas for point mutations, particularly within the mutational hot-spots, making this the first study to investigate a large number of canine fibrosarcomas. None of the samples showed a K- or N-ras hot spot mutation. Thus, our data strongly suggest that ras mutations at the hot-spot loci are very rare and do not play a major role in the pathogenesis of the spontaneously occurring canine tumours investigated.

In Hyperthermia Increased ERK and WNT Signaling Suppress Colorectal Cancer Cell Growth

PubMed Central

Bordonaro, Michael; Shirasawa, Senji; Lazarova, Darina L.

2016-01-01

Although neoplastic cells exhibit relatively higher sensitivity to hyperthermia than normal cells, hyperthermia has had variable success as an anti-cancer therapy. This variable outcome might be due to the fact that cancer cells themselves have differential degrees of sensitivity to high temperature. We hypothesized that the varying sensitivity of colorectal cancer (CRC) cells to hyperthermia depends upon the differential induction of survival pathways. Screening of such pathways revealed that Extracellular Signal-Regulated Kinase (ERK) signaling is augmented by hyperthermia, and the extent of this modulation correlates with the mutation status of V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS). Through clonal growth assays, apoptotic analyses and transcription reporter assays of CRC cells that differ only in KRAS mutation status we established that mutant KRAS cells are more sensitive to hyperthermia, as they exhibit sustained ERK signaling hyperactivation and increased Wingless/Integrated (WNT)/beta-catenin signaling. We propose that whereas increased levels of WNT and ERK signaling and a positive feedback between the two pathways is a major obstacle in anti-cancer therapy today, under hyperthermia the hyperinduction of the pathways and their positive crosstalk contribute to CRC cell death. Ascertaining the causative association between types of mutations and hyperthermia sensitivity may allow for a mutation profile-guided application of hyperthermia as an anti-cancer therapy. Since KRAS and WNT signaling mutations are prevalent in CRC, our results suggest that hyperthermia-based therapy might benefit a significant number, but not all, CRC patients. PMID:27187477

Toll-like receptor 3 as an immunotherapeutic target for KRAS mutated colorectal cancer

PubMed Central

Maitra, Radhashree; Augustine, Titto; Dayan, Yitzchak; Chandy, Carol; Coffey, Matthew; Goel, Sanjay

2017-01-01

New therapeutic interventions are essential for improved management of patients with metastatic colorectal cancer (mCRC). This is especially critical for those patients whose tumors harbor a mutation in the KRAS oncogene (40-45% of all patients). This patient cohort is excluded from receiving anti-EGFR monoclonal antibodies that have added a significant therapeutic benefit for KRAS wild type CRC patients. Reovirus, a double stranded (ds) RNA virus is in clinical development for patients with chemotherapy refractory KRAS mutated tumors. Toll Like Receptor (TLR) 3, a member of the toll like receptor family of the host innate immune system is the pattern recognition motif for dsRNA pathogens. Using TLR3 expressing commercial HEK-Blue™-hTLR3 cells we confirm that TLR3 is the host pattern recognition motif responsible for the detection of reovirus. Further, our investigation with KRAS mutated HCT116 cell line showed that effective expression of host TLR3 dampens the infection potential of reovirus by mounting a robust innate immune response. Down regulation of TLR3 expression with siRNA improves the anticancer activity of reovirus. In vivo experiments using human CRC cells derived xenografts in athymic mice further demonstrate the beneficial effects of TLR3 knock down by improving tumor response rates to reovirus. Strategies to mitigate the TLR3 response pathway can be utilized as a tool towards improved reovirus efficacy to specifically target the dissemination of KRAS mutated CRC. PMID:28422714

An integrative approach unveils FOSL1 as an oncogene vulnerability in KRAS-driven lung and pancreatic cancer.

PubMed

Vallejo, Adrian; Perurena, Naiara; Guruceaga, Elisabet; Mazur, Pawel K; Martinez-Canarias, Susana; Zandueta, Carolina; Valencia, Karmele; Arricibita, Andrea; Gwinn, Dana; Sayles, Leanne C; Chuang, Chen-Hua; Guembe, Laura; Bailey, Peter; Chang, David K; Biankin, Andrew; Ponz-Sarvise, Mariano; Andersen, Jesper B; Khatri, Purvesh; Bozec, Aline; Sweet-Cordero, E Alejandro; Sage, Julien; Lecanda, Fernando; Vicent, Silve

2017-02-21

KRAS mutated tumours represent a large fraction of human cancers, but the vast majority remains refractory to current clinical therapies. Thus, a deeper understanding of the molecular mechanisms triggered by KRAS oncogene may yield alternative therapeutic strategies. Here we report the identification of a common transcriptional signature across mutant KRAS cancers of distinct tissue origin that includes the transcription factor FOSL1. High FOSL1 expression identifies mutant KRAS lung and pancreatic cancer patients with the worst survival outcome. Furthermore, FOSL1 genetic inhibition is detrimental to both KRAS-driven tumour types. Mechanistically, FOSL1 links the KRAS oncogene to components of the mitotic machinery, a pathway previously postulated to function orthogonally to oncogenic KRAS. FOSL1 targets include AURKA, whose inhibition impairs viability of mutant KRAS cells. Lastly, combination of AURKA and MEK inhibitors induces a deleterious effect on mutant KRAS cells. Our findings unveil KRAS downstream effectors that provide opportunities to treat KRAS-driven cancers.

Distinct cellular properties of oncogenic KIT receptor tyrosine kinase mutants enable alternative courses of cancer cell inhibition

PubMed Central

Shi, Xiarong; Sousa, Leiliane P.; Mandel-Bausch, Elizabeth M.; Tome, Francisco; Reshetnyak, Andrey V.; Hadari, Yaron; Schlessinger, Joseph; Lax, Irit

2016-01-01

Large genomic sequencing analysis as part of precision medicine efforts revealed numerous activating mutations in receptor tyrosine kinases, including KIT. Unfortunately, a single approach is not effective for inhibiting cancer cells or treating cancers driven by all known oncogenic KIT mutants. Here, we show that each of the six major KIT oncogenic mutants exhibits different enzymatic, cellular, and dynamic properties and responds distinctly to different KIT inhibitors. One class of KIT mutants responded well to anti-KIT antibody treatment alone or in combination with a low dose of tyrosine kinase inhibitors (TKIs). A second class of KIT mutants, including a mutant resistant to imatinib treatment, responded well to a combination of TKI with anti-KIT antibodies or to anti-KIT toxin conjugates, respectively. We conclude that the preferred choice of precision medicine treatments for cancers driven by activated KIT and other RTKs may rely on clear understanding of the dynamic properties of oncogenic mutants. PMID:27482095

Exosomes facilitate therapeutic targeting of oncogenic KRAS in pancreatic cancer.

PubMed

Kamerkar, Sushrut; LeBleu, Valerie S; Sugimoto, Hikaru; Yang, Sujuan; Ruivo, Carolina F; Melo, Sonia A; Lee, J Jack; Kalluri, Raghu

2017-06-22

The mutant form of the GTPase KRAS is a key driver of pancreatic cancer but remains a challenging therapeutic target. Exosomes are extracellular vesicles generated by all cells, and are naturally present in the blood. Here we show that enhanced retention of exosomes, compared to liposomes, in the circulation of mice is likely due to CD47-mediated protection of exosomes from phagocytosis by monocytes and macrophages. Exosomes derived from normal fibroblast-like mesenchymal cells were engineered to carry short interfering RNA or short hairpin RNA specific to oncogenic Kras G12D , a common mutation in pancreatic cancer. Compared to liposomes, the engineered exosomes (known as iExosomes) target oncogenic KRAS with an enhanced efficacy that is dependent on CD47, and is facilitated by macropinocytosis. Treatment with iExosomes suppressed cancer in multiple mouse models of pancreatic cancer and significantly increased overall survival. Our results demonstrate an approach for direct and specific targeting of oncogenic KRAS in tumours using iExosomes.

Prx I Suppresses K-ras-Driven Lung Tumorigenesis by Opposing Redox-Sensitive ERK/Cyclin D1 Pathway

PubMed Central

Park, Young-Ho; Kim, Sun-Uk; Lee, Bo-Kyoung; Kim, Hyun-Sun; Song, In-Sung; Shin, Hye-Jun; Han, Ying-Hao; Chang, Kyu-Tae; Kim, Jin-Man; Lee, Dong-Seok; Kim, Yeul-Hong; Choi, Chang-Min; Kim, Bo-Yeon

2013-01-01

Abstract Aims: Coupled responses of mutated K-ras and oxidative stress are often an important etiological factor in non–small-cell lung cancer (NSCLC). However, relatively few studies have examined the control mechanism of oxidative stress in oncogenic K-ras-driven NSCLC progression. Here, we studied whether the redox signaling pathway governed by peroxiredoxin I (Prx I) is involved in K-rasG12D-mediated lung adenocarcinogenesis. Results: Using human-lung adenocarcinoma tissues and lung-specific K-rasG12D-transgenic mice, we found that Prx I was significantly up-regulated in the tumor regions via activation of nuclear erythroid 2-related factor 2 (Nrf2) transcription. Interestingly, the increased reactive oxygen species (ROS) by null mutation of Prx I greatly promoted K-rasG12D-driven lung tumorigenesis in number and size, which appeared to require the activation of the ROS-dependent extracellular signal-regulated kinase (ERK)/cyclin D1 pathway. Innovation: Taken together, these results suggest that Prx I functions as an Nrf2-dependently inducible tumor suppressant in K-ras-driven lung adenocarcinogenesis by opposing ROS/ERK/cyclin D1 pathway activation. Conclusion: These findings provide a better understanding of oxidative stress-mediated lung tumorigenesis. Antioxid. Redox Signal. 19, 482–496. PMID:23186333

MEK Inhibitors in the Treatment of Metastatic Melanoma and Solid Tumors.

PubMed

Grimaldi, Antonio M; Simeone, Ester; Festino, Lucia; Vanella, Vito; Strudel, Martina; Ascierto, Paolo A

2017-12-01

The mitogen-activated protein kinase (MAPK) cascade is an intracellular signaling pathway involved in the regulation of cellular proliferation and the survival of tumor cells. Several different mutations, involving BRAF or NRAS, exert an oncogenic effect by activating the MAPK pathway, resulting in an increase in cellular proliferation. These mutations have become targets for new therapeutic strategies in melanoma and other cancers. Selective MEK inhibitors have the ability to inhibit growth and induce cell death in BRAF- and NRAS-mutant melanoma cell lines. MEK inhibitor therapy in combination with a BRAF inhibitor is more effective and less toxic than treatment with a BRAF inhibitor alone, and has become the standard of care for patients with BRAF-mutated melanoma. Trametinib was the first MEK inhibitor approved for the treatment of BRAF-mutated metastatic melanoma not previously treated with BRAF inhibitors, and is also approved in combination with the BRAF inhibitor dabrafenib. Furthermore, cobimetinib is another MEK inhibitor approved for the treatment of BRAF-mutated metastatic melanoma in combination with a BRAF inhibitor, vemurafenib. The MEK inhibitor binimetinib in combination with the BRAF inhibitor encorafenib is in clinical development. The addition of an anti-PD-1/PD-L1 agent, such as pembrolizumab, durvalumab or atezolizumab, to combined BRAF and MEK inhibition has shown considerable promise, with several trials ongoing in metastatic melanoma. Binimetinib has also shown efficacy in NRAS-mutated melanoma patients. Future possibilities for MEK inhibitors in advanced melanoma, as well as other solid tumors, include their use in combination with other targeted therapies (e.g. anti-CDK4/6 inhibitors) and/or various immune-modulating antibodies.

Orphan nuclear receptor TLX functions as a potent suppressor of oncogene-induced senescence in prostate cancer via its transcriptional co-regulation of the CDKN1A (p21(WAF1) (/) (CIP1) ) and SIRT1 genes.

PubMed

Wu, Dinglan; Yu, Shan; Jia, Lin; Zou, Chang; Xu, Zhenyu; Xiao, Lijia; Wong, Kam-Bo; Ng, Chi-Fai; Chan, Franky L

2015-05-01

Oncogene-induced senescence is an important tumour-suppressing mechanism to prevent both premalignant transformation and cancer progression. Overcoming this process is a critical step in early cancer development. The druggable orphan nuclear receptor TLX (NR2E1) is characterized as an important regulator of neural stem cells and is also implicated in the development of some brain tumours. However, its exact functional roles in cancer growth regulation still remain unclear. Here we report that TLX can act as a promoter of tumourigenesis in prostate cancer by suppressing oncogene-induced senescence. We determined that TLX exhibited an increased expression in high-grade prostate cancer tissues and many prostate cancer cell lines. Functional studies revealed that TLX could perform an oncogenic function in prostate cancer cells, as its knockdown triggered cellular senescence and cell growth arrest in vitro and in vivo, whereas its over-expression promoted the malignant growth of prostate cancer cells. Furthermore, enhancement of TLX activity, by either ectopic expression or ligand stimulation, could potently prevent doxorubicin-induced senescence in prostate cancer cells and also allow prostatic epithelial cells to escape oncogene-induced senescence induced either by activated oncogene H-Ras(G12V) or knockdown of tumour suppressor PTEN, via a mechanism of direct but differential transcriptional regulation of two senescence-associated genes, repression of CDKN1A and transactivation of SIRT1. Together, our present study shows, for the first time, that TLX may play an important role in prostate carcinogenesis through its suppression of oncogene-induced senescence, and also suggests that targeting the senescence-regulatory TLX is of potential therapeutic significance in prostate cancer. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Epigenetics provides a new generation of oncogenes and tumour-suppressor genes

PubMed Central

Esteller, M

2006-01-01

Cancer is nowadays recognised as a genetic and epigenetic disease. Much effort has been devoted in the last 30 years to the elucidation of the ‘classical' oncogenes and tumour-suppressor genes involved in malignant cell transformation. However, since the acceptance that major disruption of DNA methylation, histone modification and chromatin compartments are a common hallmark of human cancer, epigenetics has come to the fore in cancer research. One piece is still missing from the story: are the epigenetic genes themselves driving forces on the road to tumorigenesis? We are in the early stages of finding the answer, and the data are beginning to appear: knockout mice defective in DNA methyltransferases, methyl-CpG-binding proteins and histone methyltransferases strongly affect the risk of cancer onset; somatic mutations, homozygous deletions and methylation-associated silencing of histone acetyltransferases, histone methyltransferases and chromatin remodelling factors are being found in human tumours; and the first cancer-prone families arising from germline mutations in epigenetic genes, such as hSNF5/INI1, have been described. Even more importantly, all these ‘new' oncogenes and tumour-suppressor genes provide novel molecular targets for designed therapies, and the first DNA-demethylating agents and inhibitors of histone deacetylases are reaching the bedside of patients with haematological malignancies. PMID:16404435

A Non-oncogenic HPV 16 E6/E7 Vaccine Enhances Treatment of HPV Expressing Tumors

PubMed Central

Wieking, Bryant G.; Vermeer, Daniel W.; Spanos, William C.; Lee, Kimberly M.; Vermeer, Paola; Lee, Walter T.; Xu, Younong; Gabitzsch, Elizabeth S.; Balcaitis, Stephanie; Balint, Joseph P.; Jones, Frank R.; Lee, John H.

2012-01-01

Human papillomaviruses (HPVs) are the causative factor for greater than 90% of cervical cancers and 25% of head and neck cancers. The incidence of HPV positive (+) head and neck squamous cell carcinomas (HNSCCs) has greatly increased in the last 30 years. E6 and E7 are the two key viral oncoproteins that induce and propagate cellular transformation. An immune response generated during cisplatin/radiation therapy improves tumor clearance of HPV(+) cancers. Augmenting this induced response during therapy with an adenoviral HPV16 E6/E7 vaccine improves long term survival in preclinical models. Here we describe the generation of an HPV16 E6/E7 construct, which contains mutations that render E6/E7 non-oncogenic, while preserving antigenicity. These mutations do not allow E6/E7 to degrade p53, pRb, PTPN13, or activate telomerase. Non-oncogenic E6/E7 (E6Δ/E7Δ) expressed as a stable integrant, or in the [E1-, E2b-] adenovirus, lacks the ability to transform human cells while retaining the ability to induce an HPV specific immune response. Moreover, E6Δ/E7Δ plus chemotherapy/radiation statistically enhances clearance of established HPV(+) cancer in vivo. PMID:22918471

Interstitial telomeric sequences in human chromosomes cluster with common fragile sites, mutagen sensitive sites, viral integration sites, cancer breakpoints, proto-oncogenes and breakpoints involved in primate evolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adekunle, S.S.A.; Wyandt, H.; Mark, H.F.L.

1994-09-01

Recently we mapped the telomeric repeat sequences to 111 interstitial sites in the human genome and to sites of gaps and breaks induced by aphidicolin and sister chromatid exchange sites detected by BrdU. Many of these sites correspond to conserved fragile sites in man, gorilla and chimpazee, to sites of conserved sister chromatid exchange in the mammalian X chromosome, to mutagenic sensitive sites, mapped locations of proto-oncogenes, breakpoints implicated in primate evolution and to breakpoints indicated as the sole anomaly in neoplasia. This observation prompted us to investigate if the interstitial telomeric sites cluster with these sites. An extensive literaturemore » search was carried out to find all the available published sites mentioned above. For comparison, we also carried out a statistical analysis of the clustering of the sites of the telomeric repeats with the gene locations where only nucleotide mutations have been observed as the only chromosomal abnormality. Our results indicate that the telomeric repeats cluster most with fragile sites, mutagenic sensitive sites and breakpoints implicated in primate evolution and least with cancer breakpoints, mapped locations of proto-oncogenes and other genes with nucleotide mutations.« less

Identification of three subgroups of B cell chronic lymphocytic leukemia based upon mutations of BCL-6 and IgV genes.

PubMed

Capello, D; Fais, F; Vivenza, D; Migliaretti, G; Chiorazzi, N; Gaidano, G; Ferrarini, M

2000-05-01

Although B cell chronic lymphocytic leukemia (B-CLL) has been traditionally viewed as a tumor of virgin B cells, this notion has been recently questioned by data suggesting that a fraction of B-CLL derives from antigen experienced B cells. In order to further clarify the histogenetic derivation of this lymphoproliferation, we have analyzed the DNA sequences of the 5' non-coding region of BCL-6 proto-oncogene in 28 cases of B-CLL. Mutations of BCL-6 proto-oncogene, a zinc finger transcription factor implicated in lymphoma development, represent a histogenetic marker of B cell transit through the germinal center (GC) and occur frequently in B cell malignancies derived from GC or post-GC B cells. For comparison, the same tumor panel was analyzed for somatic mutations of the rearranged immunoglobulin variable (IgV) genes, which are known to be acquired at the time of B cell transit through the GC. Sequence analyses of BCL-6 and IgV genes allowed the definition of three groups of B-CLL. Group I B-CLL displayed mutations of both BCL-6 and IgV genes (10/28; 36%). Group II B-CLL displayed mutated IgV genes, but a germline BCL-6 gene (5/28; 18%). Finally, group III B-CLL included the remaining cases (13/28; 46%) that were characterized by the absence of somatic mutations of both BCL-6 and IgV genes. Overall, the distribution of BCL-6 and IgV mutations in B-CLL reinforce the notion that this leukemia is histogenetically heterogeneous and that a substantial subgroup of these lymphoproliferations derives from post-germinal center B cells.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simoes, Maria L.; Hockley, Sarah L.; Schwerdtle, Tanja

Aristolochic acid (AA) is the causative agent of urothelial tumours associated with aristolochic acid nephropathy. These tumours contain TP53 mutations and over-express TP53. We compared transcriptional and translational responses of two isogenic HCT116 cell lines, one expressing TP53 (p53-WT) and the other with this gene knocked out (p53-null), to treatment with aristolochic acid I (AAI) (50-100 {mu}M) for 6-48 h. Modulation of 118 genes was observed in p53-WT cells and 123 genes in p53-null cells. Some genes, including INSIG1, EGR1, CAV1, LCN2 and CCNG1, were differentially expressed in the two cell lines. CDKN1A was selectively up-regulated in p53-WT cells, leadingmore » to accumulation of TP53 and CDKN1A. Apoptotic signalling, measured by caspase-3 and -7 activity, was TP53-dependent. Both cell types accumulated in S phase, suggesting that AAI-DNA adducts interfere with DNA replication, independently of TP53 status. The oncogene MYC, frequently over-expressed in urothelial tumours, was up-regulated by AAI, whereas FOS was down-regulated. Observed modulation of genes involved in endocytosis, e.g. RAB5A, may be relevant to the known inhibition of receptor-mediated endocytosis, an early sign of AA-mediated proximal tubule injury. AAI-DNA adduct formation was significantly greater in p53-WT cells than in p53-null cells. Collectively, phenotypic anchoring of the AAI-induced expression profiles to DNA adduct formation, cell-cycle parameters, TP53 expression and apoptosis identified several genes linked to these biological outcomes, some of which are TP53-dependent. These results strengthen the importance of TP53 in AA-induced cancer, and indicate that other alterations, e.g. to MYC oncogenic pathways, may also contribute.« less

The transforming activity of Ski and SnoN is dependent on their ability to repress the activity of Smad proteins.

PubMed

He, Jun; Tegen, Sarah B; Krawitz, Ariel R; Martin, G Steven; Luo, Kunxin

2003-08-15

The regulation of cell growth and differentiation by transforming growth factor-beta (TGF-beta) is mediated by the Smad proteins. In the nucleus, the Smad proteins are negatively regulated by two closely related nuclear proto-oncoproteins, Ski and SnoN. When overexpressed, Ski and SnoN induce oncogenic transformation of chicken embryo fibroblasts. However, the mechanism of transformation by Ski and SnoN has not been defined. We have previously reported that Ski and SnoN interact directly with Smad2, Smad3, and Smad4 and repress their ability to activate TGF-beta target genes through multiple mechanisms. Because Smad proteins are tumor suppressors, we hypothesized that the ability of Ski and SnoN to inactivate Smad function may be responsible for their transforming activity. Here, we show that the receptor regulated Smad proteins (Smad2 and Smad3) and common mediator Smad (Smad4) bind to different regions in Ski and SnoN. Mutation of both regions, but not each region alone, markedly impaired the ability of Ski and SnoN to repress TGF-beta-induced transcriptional activation and cell cycle arrest. Moreover, when expressed in chicken embryo fibroblasts, mutant Ski or SnoN defective in binding to the Smad proteins failed to induce oncogenic transformation. These results suggest that the ability of Ski and SnoN to repress the growth inhibitory function of the Smad proteins is required for their transforming activity. This may account for the resistance to TGF-beta-induced growth arrest in some human cancer cell lines that express high levels of Ski or SnoN.

MYCN-driven regulatory mechanisms controlling LIN28B in neuroblastoma

PubMed Central

Beckers, Anneleen; Van Peer, Gert; Carter, Daniel R.; Gartlgruber, Moritz; Herrmann, Carl; Agarwal, Saurabh; Helsmoortel, Hetty H.; Althoff, Kristina; Molenaar, Jan J.; Cheung, Belamy B.; Schulte, Johannes H.; Benoit, Yves; Shohet, Jason M.; Westermann, Frank; Marshall, Glenn M.; Vandesompele, Jo; De Preter, Katleen; Speleman, Frank

2016-01-01

LIN28B has been identified as an oncogene in various tumor entities, including neuroblastoma, a childhood cancer that originates from neural crest-derived cells, and is characterized by amplification of the MYCN oncogene. Recently, elevated LIN28B expression levels were shown to contribute to neuroblastoma tumorigenesis via let-7 dependent de-repression of MYCN. However, additional insight in the regulation of LIN28B in neuroblastoma is lacking. Therefore, we have performed a comprehensive analysis of the regulation of LIN28B in neuroblastoma, with a specific focus on the contribution of miRNAs. We show that MYCN regulates LIN28B expression in neuroblastoma tumors via two distinct parallel mechanisms. First, through an unbiased LIN28B-3′UTR reporter screen, we found that miR-26a-5p and miR-26b-5p regulate LIN28B expression. Next, we demonstrated that MYCN indirectly affects the expression of miR-26a-5p, and hence regulates LIN28B, therefor establishing a MYCN-miR-26a-5p-LIN28B regulatory axis. Second, we provide evidence that MYCN regulates LIN28B expression via interaction with the LIN28B promotor, establishing a direct MYCN-LIN28B regulatory axis. We believe that these findings mark LIN28B as an important effector of the MYCN oncogenic phenotype and underlines the importance of MYCN-regulated miRNAs in establishing the MYCN-driven oncogenic process. PMID:26123663

[Alterations of c-Myc and c-erbB-2 genes in ovarian tumours].

PubMed

Pastor, Tibor; Popović, Branka; Gvozdenović, Ana; Boro, Aleksandar; Petrović, Bojana; Novaković, Ivana; Puzović, Dragana; Luković, Ljiljana; Milasin, Jelena

2009-01-01

According to clinical and epidemiological studies, ovarian cancer ranks fifth in cancer deaths among women. The causes of ovarian cancer remain largely unknown but various factors may increase the risk of developing it, such as age, family history of cancer, childbearing status etc. This cancer results from a succession of genetic alterations involving oncogenes and tumour suppressor genes, which have a critical role in normal cell growth regulation. Mutations and/or overexpression of three oncogenes, c-erbB-2, c-Myc and K-ras, and of the tumour suppressor gene p53, have been frequently observed in a sporadic ovarian cancer. The aim of the present study was to analyse c-Myc and c-erbB-2 oncogene alterations, specifically amplification, as one of main mechanisms of their activation in ovarian cancers and to establish a possible association with the pathogenic process. DNA was isolated from 15 samples of malignant and 5 benign ovarian tumours, using proteinase K digestion, followed by phenol-chloroform isoamyl extraction and ethanol precipitation. C-Myc and c-erbB-2 amplification were detected by differential PCR. The level of gene copy increase was measured using the Scion image software. The amplification of both c-Myc and c-erbB-2 was detected in 26.7% of ovarian epithelial carcinoma specimens. Only one tumour specimen concomitantly showed increased gene copy number for both studied genes. Interestingly, besides amplification, gene deletion was also detected (26.7% for c-erbB-2). Most of the ovarian carcinomas with alterations in c-Myc and c-erbB-2 belonged to advanced FIGO stages. The amplification of c-Myc and c-erbB-2 oncogenes in ovarian epithelial carcinomas is most probably a late event in the pathogenesis conferring these tumours a more aggressive biological behaviour. Similarly, gene deletions point to genomic instability in epithelial carcinomas in higher clinical stages as the result of clonal evolution and selection.

miR-2909-mediated regulation of KLF4: a novel molecular mechanism for differentiating between B-cell and T-cell pediatric acute lymphoblastic leukemias

PubMed Central

2014-01-01

Background microRNAs (miRNAs) play both oncogenic and oncostatic roles in leukemia. However, the molecular details underlying miRNA-mediated regulation of their target genes in pediatric B- and T-cell acute lymphoblastic leukemias (ALLs) remain unclear. The present study investigated the relationship between miR-2909 and Kruppel-like factor 4 (KLF4), and its functional relevance to cell cycle progression and immortalization in patients with pediatric ALL. Methods Elevated levels of miR-2909 targeted the tumor suppressor gene KLF4 in pediatric B-cell, but not pediatric T-cell ALL, as detected by pMIR-GFP reporter assay. Expression levels of genes including apoptosis-antagonizing transcription factor (AATF), MYC, B-cell lymphoma (BCL3), P21 CIP , CCND1 and SP1 in B- and T-cells from patients with pediatric ALL were compared with control levels using real-time quantitative reverse transcription polymerase chain reaction, western blotting, and reporter assays. Results We identified two novel mutations in KLF4 in pediatric T-ALL. A mutation in the 3′ untranslated region of the KLF4 gene resulted in loss of miR-2909-mediated regulation, while mutation in its first or third zinc-finger motif (Zf1/Zf3) rendered KLF4 transcriptionally inactive. This mutation was a frameshift mutation resulting in alteration of the Zf3 motif sequence in the mutant KLF4 protein in all pediatric T-ALL samples. Homology models, docking studies and promoter activity of its target gene P21 CIP confirmed the lack of function of the mutant KLF4 protein in pediatric T-ALL. Moreover, the inability of miR-2909 to regulate KLF4 and its downstream genes controlling cell cycle and apoptosis in T-cell but not in B-ALL was verified by antagomiR-2909 transfection. Comprehensive sequence analysis of KLF4 identified the predominance of isoform 1 (~55 kDa) in most patients with pediatric B-ALL, while those with pediatric T-ALL expressed isoform 2 (~51 kDa). Conclusions This study identified a novel miR-2909-KLF4 molecular axis able to differentiate between the pathogeneses of pediatric B- and T-cell ALLs, and which may represent a new diagnostic/prognostic marker. PMID:25037230

Histopathological and molecular prognostic markers in medulloblastoma: c-myc, N-myc, TrkC, and anaplasia.

PubMed

Eberhart, Charles G; Kratz, John; Wang, Yunyue; Summers, Krista; Stearns, Duncan; Cohen, Kenneth; Dang, Chi V; Burger, Peter C

2004-05-01

Several molecular and histopathological prognostic markers have been proposed for the therapeutic stratification of medulloblastoma patients. Amplification of the c-myc oncogene, elevated levels of c-myc mRNA, or tumor anaplasia have been associated with worse clinical outcomes. In contrast, high TrkC mRNA expression generally presages longer survival. The goal of this study was to evaluate the prognostic value of c-myc, N-myc and TrkC expression in medulloblastomas and compare them to histopathological classification. We used in situ hybridization to measure expression of these molecular markers. c-myc mRNA was detected in 18 of 59 (31%) cases, and was significantly associated with shorter patient survival times on both univariate and multivariate analyses (p = 0.04). The presence of c-myc mRNA was also significantly associated with tumor anaplasia. While survival rates were higher for patients with low N-myc or high TrkC expression, these differences were not statistically significant. The group of patients with either moderate or severely anaplastic tumors showed only a trend towards shorter survival (p = 0.11). However, severe anaplasia alone was significantly prognostic (p = 0.002). Given the prognostic import of c-myc, we investigated 2 potential mechanisms by which its expression might be regulated: Wnt signaling and Mxi-1 mutation. Nuclear translocation of beta-catenin, a marker of Wnt pathway activation, was more common in medulloblastomas with high c-myc than in tumors overall, but the difference was not statistically significant. No Mxi-1 mutations were detected in the 22 cases examined. The association we describe between c-myc expression, tumor anaplasia, and worse clinical outcomes provides further evidence for the importance of this oncogene in medulloblastoma pathobiology.

Does Harvey-Ras gene expression lead to oral squamous cell carcinoma? A clinicopathological aspect

PubMed Central

Krishna, Akhilesh; Singh, Shraddha; Singh, Vineeta; Kumar, Vijay; Singh, Uma Shankar; Sankhwar, Satya Narayan

2018-01-01

Background: Harvey-Ras (H-Ras) is an important guanosine triphosphatase protein for the regulation of cellular growth and survival. Altered Ras signaling has been observed in different types of cancer either by gene amplification and/or mutation. The H-Ras oncogene mutations are well reported, but expression of the H-Ras gene is still unknown. Objective: This study aimed to examine both protein and messenger-RNA (mRNA) expressions of H-Ras in oral squamous cell carcinoma (OSCC) and analyzed the association with risk habits and the clinicopathological profile of cases. Methodology: A total of 65 tissue specimens of OSCC (case group) and equal number of normal tissues (control group) were included in this study. H-Ras protein and mRNA expressions were analyzed using immunohistochemical and quantitative real time-polymerase chain reaction techniques, respectively. Results: The H-Ras protein was significantly overexpressed in the oral carcinoma group compared to the normal group (P = 0.03). Most of the OSCC cases showed positive staining with moderate expression, while negative and moderate staining was high in the control group. The majority of H-Ras positive cases were found in individuals with multiple risk habits including tobacco chewing. The risk of H-Ras positivity was 1.46 times higher in smokers than non-smokers. H-Ras positivity increased in cases affected with buccal mucosa site and higher grade of carcinoma. Relative mRNA level of H-Ras was significantly elevated in oral carcinoma as compared with the control group (P ≤ 0.001). Protein and mRNA levels of H-Ras in case group was poorly correlated. Conclusion: H-Ras oncogene expression was markedly higher in oral carcinoma, and it can be a prognostic marker and target for an effective molecular therapy. PMID:29731559

Mice over-expressing human O6 alkylguanine-DNA alkyltransferase selectively reduce O6 methylguanine mediated carcinogenic mutations to threshold levels after N-methyl-N-nitrosourea.

PubMed

Allay, E; Veigl, M; Gerson, S L

1999-06-24

While it is well known that MNU induces thymic lymphomas in the mouse, it remains unclear which pre-mutagenic lesions are responsible for lymphomagenic transformation. One lesion thought to play a critical role is O6methylguanine[O6mG]which initiates G: C to A:T transition mutations in K-ras and other oncogenes. O6alkylguanine-DNA alkyltransferase (AGT), encoded by the methylguanine methyltransferase gene [MGMT], removes the methyl group thereby preventing the mutation from occurring. When overexpressed in the thymus, MGMT protects mice from MNU-induced thymic lymphomas. To determine whether MGMT overexpression reduced G: C to A: T mutation frequency after MNU, Big Blue lacI and MGMT+/Big Blue mice were treated with MNU and analysed for mutations in the lacI and K-ras genes. The incidence of MNU-induced lymphomas was 84% in Big Blue lacI mice compared to 14% in MGMT+Big Blue lacI mice. Sixty-two per cent of the lymphomas had a GGT to GAT activating mutation in codon 12 of K-ras consistent with O6mG adduct-mediated point mutagenesis. LacI mutation frequency in thymus of MNU treated Big Blue mice was 45-fold above background whereas it was 11-fold above background in MNU treated MGMT+/Big Blue mice. Most lacI mutations were G:C to A:T transitions, implicating O6mG even in the MGMT+mice. No mutations were attributable to chromosomal aberrations or rearrangements. Thus, O6mG adducts account for the carcinogenic effect of MNU and MGMT overexpression is selectively able to reduce O6methylguanine adducts below a carcinogenic threshold. Other adducts are mutagenic but appear to contribute much less to malignant transformation or oncogene activation.

Genetic disruption of oncogenic Kras sensitizes lung cancer cells to Fas receptor-mediated apoptosis.

PubMed

Mou, Haiwei; Moore, Jill; Malonia, Sunil K; Li, Yingxiang; Ozata, Deniz M; Hough, Soren; Song, Chun-Qing; Smith, Jordan L; Fischer, Andrew; Weng, Zhiping; Green, Michael R; Xue, Wen

2017-04-04

Genetic lesions that activate KRAS account for ∼30% of the 1.6 million annual cases of lung cancer. Despite clinical need, KRAS is still undruggable using traditional small-molecule drugs/inhibitors. When oncogenic Kras is suppressed by RNA interference, tumors initially regress but eventually recur and proliferate despite suppression of Kras Here, we show that tumor cells can survive knockout of oncogenic Kras , indicating the existence of Kras -independent survival pathways. Thus, even if clinical KRAS inhibitors were available, resistance would remain an obstacle to treatment. Kras -independent cancer cells exhibit decreased colony formation in vitro but retain the ability to form tumors in mice. Comparing the transcriptomes of oncogenic Kras cells and Kras knockout cells, we identified 603 genes that were specifically up-regulated in Kras knockout cells, including the Fas gene, which encodes a cell surface death receptor involved in physiological regulation of apoptosis. Antibodies recognizing Fas receptor efficiently induced apoptosis of Kras knockout cells but not oncogenic Kras -expressing cells. Increased Fas expression in Kras knockout cells was attributed to decreased association of repressive epigenetic marks at the Fas promoter. Concordant with this observation, treating oncogenic Kras cells with histone deacetylase inhibitor and Fas-activating antibody efficiently induced apoptosis, thus bypassing the need to inhibit Kras. Our results suggest that activation of Fas could be exploited as an Achilles' heel in tumors initiated by oncogenic Kras.

Genetic disruption of oncogenic Kras sensitizes lung cancer cells to Fas receptor-mediated apoptosis

PubMed Central

Mou, Haiwei; Moore, Jill; Malonia, Sunil K.; Li, Yingxiang; Ozata, Deniz M.; Hough, Soren; Song, Chun-Qing; Smith, Jordan L.; Fischer, Andrew; Weng, Zhiping; Xue, Wen

2017-01-01

Genetic lesions that activate KRAS account for ∼30% of the 1.6 million annual cases of lung cancer. Despite clinical need, KRAS is still undruggable using traditional small-molecule drugs/inhibitors. When oncogenic Kras is suppressed by RNA interference, tumors initially regress but eventually recur and proliferate despite suppression of Kras. Here, we show that tumor cells can survive knockout of oncogenic Kras, indicating the existence of Kras-independent survival pathways. Thus, even if clinical KRAS inhibitors were available, resistance would remain an obstacle to treatment. Kras-independent cancer cells exhibit decreased colony formation in vitro but retain the ability to form tumors in mice. Comparing the transcriptomes of oncogenic Kras cells and Kras knockout cells, we identified 603 genes that were specifically up-regulated in Kras knockout cells, including the Fas gene, which encodes a cell surface death receptor involved in physiological regulation of apoptosis. Antibodies recognizing Fas receptor efficiently induced apoptosis of Kras knockout cells but not oncogenic Kras-expressing cells. Increased Fas expression in Kras knockout cells was attributed to decreased association of repressive epigenetic marks at the Fas promoter. Concordant with this observation, treating oncogenic Kras cells with histone deacetylase inhibitor and Fas-activating antibody efficiently induced apoptosis, thus bypassing the need to inhibit Kras. Our results suggest that activation of Fas could be exploited as an Achilles’ heel in tumors initiated by oncogenic Kras. PMID:28320962

Oncogenic B-Raf(V600E) abrogates the AKT/B-Raf/Mps1 interaction in melanoma cells.

PubMed

Zhang, Ling; Shi, Ruyi; He, Chanting; Cheng, Caixia; Song, Bin; Cui, Heyang; Zhang, Yanyan; Zhao, Zhiping; Bi, Yanghui; Yang, Xiaofeng; Miao, Xiaoping; Guo, Jiansheng; Chen, Xing; Wang, Jinfen; Li, Yaoping; Cheng, Xiaolong; Liu, Jing; Cui, Yongping

2013-08-28

Activating B-Raf mutations that deregulate the mitogen-activated protein kinase (MAPK) pathway commonly occur in cancer. Although B-Raf(V600E) induces increased Mps1 protein contributing to centrosome amplification and chromosome instability, the regulatory mechanisms of Mps1 in melanoma cells is not fully understood. Here, we report that Mps1/AKT and B-Raf(WT)/ERK signaling form an auto-regulatory negative feedback loop in melanoma cells; notably, oncogenic B-Raf(V600E) abrogates the negative feedback loop, contributing the aberrant Mps1 functions and tumorigenesis. Our findings raise the possibility that targeting the oncogenic B-Raf and Mps1, especially when used in combination could potentially provide great therapeutic opportunities for cancer treatment. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A porcine model of osteosarcoma

PubMed Central

Saalfrank, A; Janssen, K-P; Ravon, M; Flisikowski, K; Eser, S; Steiger, K; Flisikowska, T; Müller-Fliedner, P; Schulze, É; Brönner, C; Gnann, A; Kappe, E; Böhm, B; Schade, B; Certa, U; Saur, D; Esposito, I; Kind, A; Schnieke, A

2016-01-01

We previously produced pigs with a latent oncogenic TP53 mutation. Humans with TP53 germline mutations are predisposed to a wide spectrum of early-onset cancers, predominantly breast, brain, adrenal gland cancer, soft tissue sarcomas and osteosarcomas. Loss of p53 function has been observed in >50% of human cancers. Here we demonstrate that porcine mesenchymal stem cells (MSCs) convert to a transformed phenotype after activation of latent oncogenic TP53R167H and KRASG12D, and overexpression of MYC promotes tumorigenesis. The process mimics key molecular aspects of human sarcomagenesis. Transformed porcine MSCs exhibit genomic instability, with complex karyotypes, and develop into sarcomas on transplantation into immune-deficient mice. In pigs, heterozygous knockout of TP53 was sufficient for spontaneous osteosarcoma development in older animals, whereas homozygous TP53 knockout resulted in multiple large osteosarcomas in 7–8-month-old animals. This is the first report that engineered mutation of an endogenous tumour-suppressor gene leads to invasive cancer in pigs. Unlike in Trp53 mutant mice, osteosarcoma developed in the long bones and skull, closely recapitulating the human disease. These animals thus promise a model for juvenile osteosarcoma, a relatively uncommon but devastating disease. PMID:26974205

CRISPR-mediated targeting of HER2 inhibits cell proliferation through a dominant negative mutation.

PubMed

Wang, Huajing; Sun, William

2017-01-28

With the discovery of the CRISPR/Cas9 technology, genome editing could be performed in a rapid, precise and effective manner. Its potential applications in functional interrogation of cancer-causing genes and cancer therapy have been extensively explored. In this study, we demonstrated the use of the CRISPR/Cas9 system to directly target the oncogene HER2. Directing Cas9 to exons of the HER2 gene inhibited cell growth in breast cancer cell lines that harbor amplification of the HER2 locus. The inhibitory effect was potentiated with the addition of PARP inhibitors. Unexpectedly, CRISPR-induced mutations did not significantly affect the level of HER2 protein expression. Instead, CRISPR targeting appeared to exert its effect through a dominant negative mutation. This HER2 mutant interfered with the MAPK/ERK axis of HER2 downstream signaling. Our work provides a novel mechanism underlying the anti-cancer effects of HER2-targeting by CRISPR/Cas9, which is distinct from the clinical drug Herceptin. In addition, it opens up the possibility that incomplete CRISPR targeting of certain oncogenes could still have therapeutic value by generation of dominant negative mutants. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Emerging Insights into Wnt/β-catenin Signaling in Head and Neck Cancer.

PubMed

Alamoud, K A; Kukuruzinska, M A

2018-06-01

Head and neck cancer presents primarily as head and neck squamous cell carcinoma (HNSCC), a debilitating malignancy fraught with high morbidity, poor survival rates, and limited treatment options. Mounting evidence indicates that the Wnt/β-catenin signaling pathway plays important roles in the pathobiology of HNSCC. Wnt/β-catenin signaling affects multiple cellular processes that endow cancer cells with the ability to maintain and expand immature stem-like phenotypes, proliferate, extend survival, and acquire aggressive characteristics by adopting mesenchymal traits. A central component of canonical Wnt signaling is β-catenin, which balances its role as a structural component of E-cadherin junctions with its function as a transcriptional coactivator of numerous target genes. Recent genomic characterization of head and neck cancer revealed that while β-catenin is not frequently mutated in HNSCC, its activity is unchecked by more common mutations in genes encoding upstream regulators of β-catenin, NOTCH1, FAT1, and AJUBA. Wnt/β-catenin signaling affects a wide range epigenetic and transcriptional activities, mediated by the interaction of β-catenin with different transcription factors and transcriptional coactivators and corepressors. Furthermore, Wnt/β-catenin functions in a network with many signaling and metabolic pathways that modulate its activity. In addition to its effects on tumor epithelia, β-catenin activity regulates the tumor microenvironment by regulating extracellular matrix remodeling, fibrotic processes, and immune response. These multifunctional oncogenic effects of β-catenin make it an attractive bona fide target for HNSCC therapy.

Direct regulation of the Akt proto-oncogene product by phosphatidylinositol-3,4-bisphosphate.

PubMed

Franke, T F; Kaplan, D R; Cantley, L C; Toker, A

1997-01-31

The regulation of the serine-threonine kinase Akt by lipid products of phosphoinositide 3-kinase (PI 3-kinase) was investigated. Akt activity was found to correlate with the amount of phosphatidylinositol-3,4-bisphosphate (PtdIns-3,4-P2) in vivo, and synthetic PtdIns-3,4-P2 activated Akt both in vitro and in vivo. Binding of PtdIns-3,4-P2 occurred within the Akt pleckstrin homology (PH) domain and facilitated dimerization of Akt. Akt mutated in the PH domain was not activated by PI 3-kinase in vivo or by PtdIns-3, 4-P2 in vitro, and it was impaired in binding to PtdIns-3,4-P2. Examination of the binding to other phosphoinositides revealed that they bound to the Akt PH domain with much lower affinity than did PtdIns-3,4-P2 and failed to increase Akt activity. Thus, Akt is apparently regulated by the direct interaction of PtdIns-3,4-P2 with the Akt PH domain.

GLI1, a master regulator of the hallmark of pancreatic cancer.

PubMed

Kasai, Kenji

2016-12-01

Hedgehog signaling is highly conserved across species and governs proper embryonic development. Germline gene mutations that reduce this signaling activity cause a variety of developmental abnormalities such as holoprosencephaly, while those that enhance Hedgehog signaling activity induce a tumor-predisposition condition Nevoid basal cell carcinoma syndrome. Furthermore, dysregulated activation of Hedgehog signaling has been recognized in various sporadic malignancies, including pancreatic adenocarcinoma. Pancreatic adenocarcinoma develops through a multistep carcinogenesis starting with oncogenic mutation of the KRAS gene. During this process, precancerous or cancer cells secrete Hedgehog ligand proteins to promote characteristic desmoplastic stroma around the cells, which in turn activates the expression of the downstream transcription factor GLI1 inside the cells. The quantitative and spatiotemporal dysregulation of GLI1 subsequently leads to the expression of transcriptional target genes of GLI1 that govern the hallmark of malignant properties. Here, after a brief introductory outline, a perspective is offered of Hedgehog signaling with a special focus on the role of GLI1 in pancreatic carcinogenesis. © 2016 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.

Molecular basis for the role of oncogenic histone mutations in modulating H3K36 methylation

DOE PAGES

Zhang, Yinglu; Shan, Chun -Min; Wang, Jiyong; ...

2017-03-03

Histone H3 lysine 36 methylation (H3K36me) is critical for epigenetic regulation and mutations at or near H3K36 are associated with distinct types of cancers. H3K36M dominantly inhibits H3K36me on wild-type histones, whereas H3G34R/V selectively affects H3K36me on the same histone tail. Here we report the crystal structures of SETD2 SET domain in complex with an H3K36M peptide and SAM or SAH. There are large conformational changes in the substrate binding regions of the SET domain, and the K36M residue interacts with the catalytic pocket of SETD2. H3G34 is surrounded by a very narrow tunnel, which excludes larger amino acid sidemore » chains. H3P38 is in the trans configuration, and the cis configuration is incompatible with SETD2 binding. Lastly, mutations of H3G34 or H3P38 alleviate the inhibitory effects of H3K36M on H3K36me, demonstrating that the stable interaction of H3K36M with SETD2 is critical for its inhibitory effects.« less

CpG island methylator phenotype in adenocarcinomas from the digestive tract: Methods, conclusions, and controversies

PubMed Central

Sánchez-Vega, Francisco; Gotea, Valer; Chen, Yun-Ching; Elnitski, Laura

2017-01-01

Over the last two decades, cancer-related alterations in DNA methylation that regulate transcription have been reported for a variety of tumors of the gastrointestinal tract. Due to its relevance for translational research, great emphasis has been placed on the analysis and molecular characterization of the CpG island methylator phenotype (CIMP), defined as widespread hypermethylation of CpG islands in clinically distinct subsets of cancer patients. Here, we present an overview of previous work in this field and also explore some open questions using cross-platform data for esophageal, gastric, and colorectal adenocarcinomas from The Cancer Genome Atlas. We provide a data-driven, pan-gastrointestinal stratification of individual samples based on CIMP status and we investigate correlations with oncogenic alterations, including somatic mutations and epigenetic silencing of tumor suppressor genes. Besides known events in CIMP such as BRAF V600E mutation, CDKN2A silencing or MLH1 inactivation, we discuss the potential role of emerging actors such as Wnt pathway deregulation through truncating mutations in RNF43 and epigenetic silencing of WIF1. Our results highlight the existence of molecular similarities that are superimposed over a larger backbone of tissue-specific features and can be exploited to reduce heterogeneity of response in clinical trials. PMID:28344746

Exosomes as mediators of platinum resistance in ovarian cancer.

PubMed

Crow, Jennifer; Atay, Safinur; Banskota, Samagya; Artale, Brittany; Schmitt, Sarah; Godwin, Andrew K

2017-02-14

Exosomes have been implicated in the cell-cell transfer of oncogenic proteins and genetic material. We speculated this may be one mechanism by which an intrinsically platinum-resistant population of epithelial ovarian cancer (EOC) cells imparts its influence on surrounding tumor cells. To explore this possibility we utilized a platinum-sensitive cell line, A2780 and exosomes derived from its resistant subclones, and an unselected, platinum-resistant EOC line, OVCAR10. A2780 cells demonstrate a ~2-fold increase in viability upon treatment with carboplatin when pre-exposed to exosomes from platinum-resistant cells as compared to controls. This coincided with increased epithelial to mesenchymal transition (EMT). DNA sequencing of EOC cell lines revealed previously unreported somatic mutations in the Mothers Against Decapentaplegic Homolog 4 (SMAD4) within platinum-resistant cells. A2780 cells engineered to exogenously express these SMAD4 mutations demonstrate up-regulation of EMT markers following carboplatin treatment, are more resistant to carboplatin, and release exosomes which impart a ~1.7-fold increase in resistance in naive A2780 recipient cells as compared to controls. These studies provide the first evidence that acquired SMAD4 mutations enhance the chemo-resistance profile of EOC and present a novel mechanism in which exchange of tumor-derived exosomes perpetuates an EMT phenotype, leading to the development of subpopulations of platinum-refractory cells.

New roles for Dicer in the nucleolus and its relevance to cancer.

PubMed

Roche, Benjamin; Arcangioli, Benoît; Martienssen, Rob

2017-09-17

The nucleolus is a distinct compartment of the nucleus responsible for ribosome biogenesis. Mis-regulation of nucleolar functions and of the cellular translation machinery has been associated with disease, in particular with many types of cancer. Indeed, many tumor suppressors (p53, Rb, PTEN, PICT1, BRCA1) and proto-oncogenes (MYC, NPM) play a direct role in the nucleolus, and interact with the RNA polymerase I transcription machinery and the nucleolar stress response. We have identified Dicer and the RNA interference pathway as having an essential role in the nucleolus of quiescent Schizosaccharomyces pombe cells, distinct from pericentromeric silencing, by controlling RNA polymerase I release. We propose that this novel function is evolutionarily conserved and may contribute to the tumorigenic pre-disposition of DICER1 mutations in mammals.

Specific cancer-associated mutations in the switch III region of Ras increase tumorigenicity by nanocluster augmentation

PubMed Central

Šolman, Maja; Ligabue, Alessio; Blaževitš, Olga; Jaiswal, Alok; Zhou, Yong; Liang, Hong; Lectez, Benoit; Kopra, Kari; Guzmán, Camilo; Härmä, Harri; Hancock, John F; Aittokallio, Tero; Abankwa, Daniel

2015-01-01

Hotspot mutations of Ras drive cell transformation and tumorigenesis. Less frequent mutations in Ras are poorly characterized for their oncogenic potential. Yet insight into their mechanism of action may point to novel opportunities to target Ras. Here, we show that several cancer-associated mutations in the switch III region moderately increase Ras activity in all isoforms. Mutants are biochemically inconspicuous, while their clustering into nanoscale signaling complexes on the plasma membrane, termed nanocluster, is augmented. Nanoclustering dictates downstream effector recruitment, MAPK-activity, and tumorigenic cell proliferation. Our results describe an unprecedented mechanism of signaling protein activation in cancer. DOI: http://dx.doi.org/10.7554/eLife.08905.001 PMID:26274561

Risk for Sporadic Breast Cancer in Ataxia Telangiectasia Heterozygotes

DTIC Science & Technology

2001-08-01

assess whether heterozygosity for the ATM gene, due to a loss of function mutation in one of the 2 alleles and found in about 1% of the general population...suppressor role in breast cancer, a loss of wild type ATM expression rather than mutational inactivation could be expected. With this rationale, we...genes. The latter indicates that in p53-deficient tumor cells with activated oncogenic pathways, clonal outgrowth favors loss of p73 function. Taken

ONCOGENIC BASE SUBSTITUTION MUTATIONS IN CIRCULATING LEUKOCYTES OF NORMAL INDIVIDUALS. (R825810)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Estrogens and human papilloma virus oncogenes regulate human ether-à-go-go-1 potassium channel expression.

PubMed

Díaz, Lorenza; Ceja-Ochoa, Irais; Restrepo-Angulo, Iván; Larrea, Fernando; Avila-Chávez, Euclides; García-Becerra, Rocío; Borja-Cacho, Elizabeth; Barrera, David; Ahumada, Elías; Gariglio, Patricio; Alvarez-Rios, Elizabeth; Ocadiz-Delgado, Rodolfo; Garcia-Villa, Enrique; Hernández-Gallegos, Elizabeth; Camacho-Arroyo, Ignacio; Morales, Angélica; Ordaz-Rosado, David; García-Latorre, Ethel; Escamilla, Juan; Sánchez-Peña, Luz Carmen; Saqui-Salces, Milena; Gamboa-Dominguez, Armando; Vera, Eunice; Uribe-Ramírez, Marisela; Murbartián, Janet; Ortiz, Cindy Sharon; Rivera-Guevara, Claudia; De Vizcaya-Ruiz, Andrea; Camacho, Javier

2009-04-15

Ether-à-go-go-1 (Eag1) potassium channels are potential tools for detection and therapy of numerous cancers. Here, we show human Eag1 (hEag1) regulation by cancer-associated factors. We studied hEag1 gene expression and its regulation by estradiol, antiestrogens, and human papillomavirus (HPV) oncogenes (E6/E7). Primary cultures from normal placentas and cervical cancer tissues; tumor cell lines from cervix, choriocarcinoma, keratinocytes, and lung; and normal cell lines from vascular endothelium, keratinocytes, and lung were used. Reverse transcription-PCR (RT-PCR) experiments and Southern blot analysis showed Eag1 expression in all of the cancer cell types, normal trophoblasts, and vascular endothelium, in contrast to normal keratinocytes and lung cells. Estradiol and antiestrogens regulated Eag1 in a cell type-dependent manner. Real-time RT-PCR experiments in HeLa cells showed that Eag1 estrogenic regulation was strongly associated with the expression of estrogen receptor-alpha. Eag1 protein was detected by monoclonal antibodies in normal placenta and placental blood vessels. Patch-clamp recordings in normal trophoblasts treated with estradiol exhibited potassium currents resembling Eag1 channel activity. Eag1 gene expression in keratinocytes depended either on cellular immortalization or the presence of HPV oncogenes. Eag1 protein was found in keratinocytes transfected with E6/E7 HPV oncogenes. Cell proliferation of E6/E7 keratinocytes was decreased by Eag1 antibodies inhibiting channel activity and by the nonspecific Eag1 inhibitors imipramine and astemizole; the latter also increased apoptosis. Our results propose novel oncogenic mechanisms of estrogen/antiestrogen use and HPV infection. We also suggest Eag1 as an early indicator of cell proliferation leading to malignancies and a therapeutic target at early stages of cellular hyperproliferation.

The Wnt/β-catenin pathway is deregulated in cemento-ossifying fibromas.

PubMed

Pereira, Thaís Dos Santos Fontes; Diniz, Marina Gonçalves; França, Josiane Alves; Moreira, Rennan Garcias; Menezes, Grazielle Helena Ferreira de; Sousa, Sílvia Ferreira de; Castro, Wagner Henriques de; Gomes, Carolina Cavaliéri; Gomez, Ricardo Santiago

2018-02-01

The molecular pathogenesis of cemento ossifying fibroma (COF) is unclear. The purpose of this study was to investigate mutations in 50 oncogenes and tumor suppressor genes, including APC and CTNNB1, in which mutations in COF have been previously reported. In addition, we assessed the transcriptional levels of the Wnt/β-catenin pathway genes in COF. We used a quantitative polymerase chain reaction array to evaluate the transcriptional levels of 44 Wnt/β-catenin pathway genes in 6 COF samples, in comparison with 6 samples of healthy jaws. By using next-generation sequencing (NGS) in 7 COF samples, we investigated approximately 2800 mutations in 50 genes. The expression assay revealed 12 differentially expressed Wnt/β-catenin pathway genes in COF, including the upregulation of CTNNB1, TCF7, NKD1, and WNT5 A, and downregulation of CTNNBIP1, FRZB, FZD6, RHOU, SFRP4, WNT10 A, WNT3 A, and WNT4, suggesting activation of the Wnt/β-catenin signaling pathway. NGS revealed 5 single nucleotide variants: TP53 (rs1042522), PIK3 CA (rs2230461), MET (rs33917957), KIT (rs3822214), and APC (rs33974176), but none of them was pathogenic. Although NGS detected no oncogenic mutation, deregulation of key Wnt/β-catenin signaling pathway genes appears to be relevant to the molecular pathogenesis of COF. Copyright © 2017 Elsevier Inc. All rights reserved.

Machine Learning-Assisted Network Inference Approach to Identify a New Class of Genes that Coordinate the Functionality of Cancer Networks.

PubMed

Ghanat Bari, Mehrab; Ung, Choong Yong; Zhang, Cheng; Zhu, Shizhen; Li, Hu

2017-08-01

Emerging evidence indicates the existence of a new class of cancer genes that act as "signal linkers" coordinating oncogenic signals between mutated and differentially expressed genes. While frequently mutated oncogenes and differentially expressed genes, which we term Class I cancer genes, are readily detected by most analytical tools, the new class of cancer-related genes, i.e., Class II, escape detection because they are neither mutated nor differentially expressed. Given this hypothesis, we developed a Machine Learning-Assisted Network Inference (MALANI) algorithm, which assesses all genes regardless of expression or mutational status in the context of cancer etiology. We used 8807 expression arrays, corresponding to 9 cancer types, to build more than 2 × 10 8 Support Vector Machine (SVM) models for reconstructing a cancer network. We found that ~3% of ~19,000 not differentially expressed genes are Class II cancer gene candidates. Some Class II genes that we found, such as SLC19A1 and ATAD3B, have been recently reported to associate with cancer outcomes. To our knowledge, this is the first study that utilizes both machine learning and network biology approaches to uncover Class II cancer genes in coordinating functionality in cancer networks and will illuminate our understanding of how genes are modulated in a tissue-specific network contribute to tumorigenesis and therapy development.

Differential sensitivity of melanoma cell lines with BRAFV600E mutation to the specific Raf inhibitor PLX4032

PubMed Central

2010-01-01

Blocking oncogenic signaling induced by the BRAFV600E mutation is a promising approach for melanoma treatment. We tested the anti-tumor effects of a specific inhibitor of Raf protein kinases, PLX4032/RG7204, in melanoma cell lines. PLX4032 decreased signaling through the MAPK pathway only in cell lines with the BRAFV600E mutation. Seven out of 10 BRAFV600E mutant cell lines displayed sensitivity based on cell viability assays and three were resistant at concentrations up to 10 μM. Among the sensitive cell lines, four were highly sensitive with IC50 values below 1 μM, and three were moderately sensitive with IC50 values between 1 and 10 μM. There was evidence of MAPK pathway inhibition and cell cycle arrest in both sensitive and resistant cell lines. Genomic analysis by sequencing, genotyping of close to 400 oncogeninc mutations by mass spectrometry, and SNP arrays demonstrated no major differences in BRAF locus amplification or in other oncogenic events between sensitive and resistant cell lines. However, metabolic tracer uptake studies demonstrated that sensitive cell lines had a more profound inhibition of FDG uptake upon exposure to PLX4032 than resistant cell lines. In conclusion, BRAFV600E mutant melanoma cell lines displayed a range of sensitivities to PLX4032 and metabolic imaging using PET probes can be used to assess sensitivity. PMID:20406486

Pathogenesis of thyroid nodules: histological classification?

PubMed

Salabè, G B

2001-02-01

Thyroid nodule genesis may be considered as an amplification of thyroid heterogeneity due to genetic and/or epigenetic mechanisms. We classified the thyroid nodules in five types with distinct histological features: hyperplastic, neoplastic, colloid, cystic and thyroiditic nodules. Hyperplastic: Thyrocyte proliferation is under the control of TSH but several other paracrine and autocrine factors are secreted by follicular cells, the stromal apparatus and the lymphocytes, which are implicated in initiation and perpetuation of thyroid hyperplasia. Growth occurs mainly through TSHR, cAMP and PKA. Constitutive cAMP overproduction has been shown to be due to point mutation of the TSHR or Gs protein, producing overgrowth and hyperfunction. Neoplastic: Several activated oncogenes have been identified in thyroid malignancies. Oncogenes relevant to the thyroid carcinogenesis are: mutated TSHR and gsp (constitutive activation of cAMP); TRK (receptor for NGF); RET/PTC (phosphorylation of tyrosine kinase receptor)--an isoform of this oncogene is induced by radiation: ras (it encodes Gs proteins transducing mitogenic signals); and c-MET (receptor for hepatocyte growth factor). The evolution of a differentiated thyroid cancer towards an undifferentiated cancer is due to a mutation of a family of proteins (i.e., p53), which acts as a brake, preventing the genomic instability of cancer. It is suggested that a tumor initiates by RET or ras and possibly progresses--as a result of additional mutations and by p53 mutation--to anaplastic carcinoma. Colloid: Flattening of the epithelium and dilatation of follicles containing viscous material--made up by a concentrated solution of thyroglobulin (hTg)--is the characteristic of the colloid nodule. A defect of intraluminal reabsorption of hTg has been suggested but not proven. Experimentally, a load of iodine is able to change thyroid hyperplasia to a colloid feature; however, a load of iodine is rarely found in the clinical history of patients. A new clue to the pathogenesis comes from the finding that a relevant part of the colloid (10-20%) is made up of insoluble globules, where hTg is compacted in a polymeric form. It is suggested that stocking hTg into globules is defective in colloid nodules, leading to enormous enlargement of the follicle. Cystic: It is estimated that between 15 and 40% of thyroid nodules are partly or entirely cystic. The 'true cyst' is rare; most of the so-called cystic nodules are 'pseudocysts', which follow necrosis and colliquation. Necrosis issues as an imbalance between growth and the precisely regulated process of angiogenesis. More recently, the VEGF/VPF has been found to be at the origin of recent and recurrent cysts. Immunotoxic and apoptotic mechanisms have also been suggested. Chemical analysis of cystic fluid showed a 'denatured' and 'serum-like' pattern suggesting different mechanisms in the pathogenesis of the pseudocystic thyroid nodules. Thyroiditic: Nodular lymphocytic thyroiditis (NLT) includes two different entities: 1) lymphocyte thyroiditis growing as a nodule in a hyperplastic or normal gland, and 2) lymphocyte thyroiditis associated in the same nodule with other nodular diseases of the thyroid: papillary thyroid carcinoma and lymphoma have been found to be associated to chronic lymphocytic thyroiditis.

Navigator-3, a modulator of cell migration, may act as a suppressor of breast cancer progression

PubMed Central

Cohen-Dvashi, Hadas; Ben-Chetrit, Nir; Russell, Roslin; Carvalho, Silvia; Lauriola, Mattia; Nisani, Sophia; Mancini, Maicol; Nataraj, Nishanth; Kedmi, Merav; Roth, Lee; Köstler, Wolfgang; Zeisel, Amit; Yitzhaky, Assif; Zylberg, Jacques; Tarcic, Gabi; Eilam, Raya; Wigelman, Yoav; Will, Rainer; Lavi, Sara; Porat, Ziv; Wiemann, Stefan; Ricardo, Sara; Schmitt, Fernando; Caldas, Carlos; Yarden, Yosef

2015-01-01

Dissemination of primary tumor cells depends on migratory and invasive attributes. Here, we identify Navigator-3 (NAV3), a gene frequently mutated or deleted in human tumors, as a regulator of epithelial migration and invasion. Following induction by growth factors, NAV3 localizes to the plus ends of microtubules and enhances their polarized growth. Accordingly, NAV3 depletion trimmed microtubule growth, prolonged growth factor signaling, prevented apoptosis and enhanced random cell migration. Mathematical modeling suggested that NAV3-depleted cells acquire an advantage in terms of the way they explore their environment. In animal models, silencing NAV3 increased metastasis, whereas ectopic expression of the wild-type form, unlike expression of two, relatively unstable oncogenic mutants from human tumors, inhibited metastasis. Congruently, analyses of > 2,500 breast and lung cancer patients associated low NAV3 with shorter survival. We propose that NAV3 inhibits breast cancer progression by regulating microtubule dynamics, biasing directionally persistent rather than random migration, and inhibiting locomotion of initiated cells. PMID:25678558

A Structural Perspective on the Regulation of the EGF Receptor

PubMed Central

Kovacs, Erika; Zorn, Julie Anne; Huang, Yongjian; Barros, Tiago; Kuriyan, John

2015-01-01

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that plays a critical role in the pathogenesis of many cancers. EGFR is unique in that its ligand-induced dimerization is established solely by contacts between regions of the receptor that are occluded within the monomeric, unliganded state. Activation of EGFR depends on the formation of an asymmetric dimer of the intracellular module of two receptor molecules, a configuration observed in crystal structures of the EGFR kinase domain in the active state. Coupling between the extracellular and intracellular modules is achieved by a switch between alternative geometries of the transmembrane and juxtamembrane segments within the receptor dimer. As the structure of the full-length receptor is yet to be determined, here we review recent structural studies on isolated modules of EGFR and molecular dynamics simulations that have provided much of our current understanding of its signaling mechanism, including how its regulation is compromised by oncogenic mutations. PMID:25621509

Ski and SnoN, potent negative regulators of TGF-β signaling

PubMed Central

Deheuninck, Julien; Luo, Kunxin

2011-01-01

Ski and the closely related SnoN were discovered as oncogenes by their ability to transform chicken embryo fibroblasts upon overexpression. While elevated expressions of Ski and SnoN have also been reported in many human cancer cells and tissues, consistent with their pro-oncogenic activity, emerging evidence also suggests a potential anti-oncogenic activity for both. In addition, Ski and SnoN have been implicated in regulation of cell differentiation, especially in the muscle and neuronal lineages. Multiple cellular partners of Ski and SnoN have been identified in an effort to understand the molecular mechanisms underlying the complex roles of Ski and SnoN. In this review, we summarize recent findings on the biological functions of Ski and SnoN, their mechanisms of action and how their levels of expression are regulated. PMID:19114989

Tumor-associated macrophages promote neuroblastoma via STAT3 phosphorylation and up-regulation of c-MYC

PubMed Central

Hadjidaniel, Michael D.; Muthugounder, Sakunthala; Hung, Long T.; Sheard, Michael A.; Shirinbak, Soheila; Chan, Randall Y.; Nakata, Rie; Borriello, Lucia; Malvar, Jemily; Kennedy, Rebekah J.; Iwakura, Hiroshi; Akamizu, Takashi; Sposto, Richard; Shimada, Hiroyuki; DeClerck, Yves A.; Asgharzadeh, Shahab

2017-01-01

Tumor-associated macrophages (TAMs) are strongly associated with poor survival in neuroblastomas that lack MYCN amplification. To study TAM action in neuroblastomas, we used a novel murine model of spontaneous neuroblastoma lacking MYCN amplification, and observed recruitment and polarization of TAMs, which in turn enhanced neuroblastoma proliferation and growth. In both murine and human neuroblastoma cells, we found that TAMs increased STAT3 activation in neuroblastoma cells and transcriptionally up-regulated the MYC oncogene. Analysis of human neuroblastoma tumor specimens revealed that MYC up-regulation correlates with markers of TAM infiltration. In an IL6ko neuroblastoma model, the absence of IL-6 protein had no effect on tumor development and prevented neither STAT3 activation nor MYC up-regulation. In contrast, inhibition of JAK-STAT activation using AZD1480 or the clinically admissible inhibitor ruxolitinib significantly reduced TAM-mediated growth of neuroblastomas implanted subcutaneously in NOD scid gamma mice. Our results point to a unique mechanism in which TAMs promote tumor cells that lack amplification of an oncogene common to the malignancy by up-regulating transcriptional expression of a distinct oncogene from the same gene family, and underscore the role of IL-6-independent activation of STAT3 in this mechanism. Amplification of MYCN or constitutive up-regulation of MYC protein is observed in approximately half of high-risk tumors; our findings indicate a novel role of TAMs as inducers of MYC expression in neuroblastomas lacking independent oncogene activation. PMID:29207662

A Landscape of Driver Mutations in Melanoma

PubMed Central

Hodis, Eran; Watson, Ian R.; Kryukov, Gregory V.; Arold, Stefan T.; Imielinski, Marcin; Theurillat, Jean-Philippe; Nickerson, Elizabeth; Auclair, Daniel; Li, Liren; Place, Chelsea; DiCara, Daniel; Ramos, Alex H.; Lawrence, Michael S.; Cibulskis, Kristian; Sivachenko, Andrey; Voet, Douglas; Saksena, Gordon; Stransky, Nicolas; Onofrio, Robert C.; Winckler, Wendy; Ardlie, Kristin; Wagle, Nikhil; Wargo, Jennifer; Chong, Kelly; Morton, Donald L.; Stemke-Hale, Katherine; Chen, Guo; Noble, Michael; Meyerson, Matthew; Ladbury, John E.; Davies, Michael A.; Gershenwald, Jeffrey E.; Wagner, Stephan N.; Hoon, Dave S.B.; Schadendorf, Dirk; Lander, Eric S.; Gabriel, Stacey B.; Getz, Gad; Garraway, Levi A.; Chin, Lynda

2012-01-01

SUMMARY Despite recent insights into melanoma genetics, systematic surveys for driver mutations are challenged by an abundance of passenger mutations caused by carcinogenic ultraviolet (UV) light exposure. We developed a permutation-based framework to address this challenge, employing mutation data from intronic sequences to control for passenger mutational load on a per gene basis. Analysis of large-scale melanoma exome data by this approach discovered six novel melanoma genes (PPP6C, RAC1, SNX31, TACC1, STK19 and ARID2), three of which - RAC1, PPP6C and STK19 - harbored recurrent and potentially targetable mutations. Integration with chromosomal copy number data contextualized the landscape of driver mutations, providing oncogenic insights in BRAF- and NRAS-driven melanoma as well as those without known NRAS/BRAF mutations. The landscape also clarified a mutational basis for RB and p53 pathway deregulation in this malignancy. Finally, the spectrum of driver mutations provided unequivocal genomic evidence for a direct mutagenic role of UV light in melanoma pathogenesis. PMID:22817889

Expression of Abelson Interactor 1 (Abi1) Correlates with Inflammation, KRAS Mutation and Adenomatous Change during Colonic Carcinogenesis

PubMed Central

Steinestel, Konrad; Brüderlein, Silke; Steinestel, Julie; Märkl, Bruno; Schwerer, Michael J.; Arndt, Annette; Kraft, Klaus; Pröpper, Christian; Möller, Peter

2012-01-01

Background Abelson interactor 1 (Abi1) is an important regulator of actin dynamics during cytoskeletal reorganization. In this study, our aim was to investigate the expression of Abi1 in colonic mucosa with and without inflammation, colonic polyps, colorectal carcinomas (CRC) and metastases as well as in CRC cell lines with respect to BRAF/KRAS mutation status and to find out whether introduction of KRAS mutation or stimulation with TNFalpha enhances Abi1 protein expression in CRC cells. Methodology/Principal Findings We immunohistochemically analyzed Abi1 protein expression in 126 tissue specimens from 95 patients and in 5 colorectal carcinoma cell lines with different mutation status by western immunoblotting. We found that Abi1 expression correlated positively with KRAS, but not BRAF mutation status in the examined tissue samples. Furthermore, Abi1 is overexpressed in inflammatory mucosa, sessile serrated polyps and adenomas, tubular adenomas, invasive CRC and CRC metastasis when compared to healthy mucosa and BRAF-mutated as well as KRAS wild-type hyperplastic polyps. Abi1 expression in carcinoma was independent of microsatellite stability of the tumor. Abi1 protein expression correlated with KRAS mutation in the analyzed CRC cell lines, and upregulation of Abi1 could be induced by TNFalpha treatment as well as transfection of wild-type CRC cells with mutant KRAS. The overexpression of Abi1 could be abolished by treatment with the PI3K-inhibitor Wortmannin after KRAS transfection. Conclusions/Significance Our results support a role for Abi1 as a downstream target of inflammatory response and adenomatous change as well as oncogenic KRAS mutation via PI3K, but not BRAF activation. Furthermore, they highlight a possible role for Abi1 as a marker for early KRAS mutation in hyperplastic polyps. Since the protein is a key player in actin dynamics, our data encourages further studies concerning the exact role of Abi1 in actin reorganization upon enhanced KRAS/PI3K signalling during colonic tumorigenesis. PMID:22808230

Molecular biology of pancreatic cancer.

PubMed

Zavoral, Miroslav; Minarikova, Petra; Zavada, Filip; Salek, Cyril; Minarik, Marek

2011-06-28

In spite of continuous research efforts directed at early detection and treatment of pancreatic cancer, the outlook for patients affected by the disease remains dismal. With most cases still being diagnosed at advanced stages, no improvement in survival prognosis is achieved with current diagnostic imaging approaches. In the absence of a dominant precancerous condition, several risk factors have been identified including family history, chronic pancreatitis, smoking, diabetes mellitus, as well as certain genetic disorders such as hereditary pancreatitis, cystic fibrosis, familial atypical multiple mole melanoma, and Peutz-Jeghers and Lynch syndromes. Most pancreatic carcinomas, however, remain sporadic. Current progress in experimental molecular techniques has enabled detailed understanding of the molecular processes of pancreatic cancer development. According to the latest information, malignant pancreatic transformation involves multiple oncogenes and tumor-suppressor genes that are involved in a variety of signaling pathways. The most characteristic aberrations (somatic point mutations and allelic losses) affect oncogenes and tumor-suppressor genes within RAS, AKT and Wnt signaling, and have a key role in transcription and proliferation, as well as systems that regulate the cell cycle (SMAD/DPC, CDKN2A/p16) and apoptosis (TP53). Understanding of the underlying molecular mechanisms should promote development of new methodology for early diagnosis and facilitate improvement in current approaches for pancreatic cancer treatment.

Severe Clinical Course in a Patient with Congenital Amegakaryocytic Thrombocytopenia Due to a Missense Mutation of the c-MPL Gene.

PubMed

Ok Bozkaya, İkbal; Yaralı, Neşe; Işık, Pamir; Ünsal Saç, Rukiye; Tavil, Betül; Tunç, Bahattin

2015-06-01

Congenital amegakaryocytic thrombocytopenia (CAMT) generally begins at birth with severe thrombocytopenia and progresses to pancytopenia. It is caused by mutations in the thrombopoietin receptor gene, the myeloproliferative leukemia virus oncogene (c-MPL). The association between CAMT and c-MPL mutation type has been reported in the literature. Patients with CAMT have been categorized according to their clinical symptoms caused by different mutations. Missense mutations of c-MPL have been classified as type II and these patients have delayed onset of bone marrow failure compared to type I patients. Here we present a girl with severe clinical course of CAMT II having a missense mutation in exon 4 of the c-MPL gene who was admitted to our hospital with intracranial hemorrhage during the newborn period.

Corruption of homeostatic mechanisms in the guanylyl cyclase C signaling pathway underlying colorectal tumorigenesis

PubMed Central

Waldman, Scott A

2010-01-01

Colon cancer, the second leading cause of cancer-related mortality worldwide, originates from the malignant transformation of intestinal epithelial cells. The intestinal epithelium undergoes a highly organized process of rapid regeneration along the crypt-villus axis, characterized by proliferation, migration, differentiation and apoptosis, whose coordination is essential to maintaining the mucosal barrier. Disruption of these homeostatic processes predisposes cells to mutations in tumor suppressors or oncogenes, whose dysfunction provides transformed cells an evolutionary growth advantage. While sequences of genetic mutations at different stages along the neoplastic continuum have been established, little is known of the events initiating tumorigenesis prior to adenomatous polyposis coli (APC) mutations. Here, we examine a role for the corruption of homeostasis induced by silencing novel tumor suppressors, including the intestine-specific transcription factor CDX2 and its gene target guanylyl cyclase C (GCC), as early events predisposing cells to mutations in APC and other sequential genes that initiate colorectal cancer. CDX2 and GCC maintain homeostatic regeneration in the intestine by restricting cell proliferation, promoting cell maturation and adhesion, regulating cell migration and defending the intestinal barrier and genomic integrity. Elimination of CDX2 or GCC promotes intestinal tumor initiation and growth in aged mice, mice carrying APC mutations or mice exposed to carcinogens. The roles of CDX2 and GCC in suppressing intestinal tumorigenesis, universal disruption in their signaling through silencing of hormones driving GCC, and the uniform overexpression of GCC by tumors underscore the potential value of oral replacement with GCC ligands as targeted prevention and therapy for colorectal cancer. PMID:20592492

Activation Of Wild-Type Hras Suppresses The Earliest Stages Of Pancreatic Cancer.

PubMed

Weyandt, Jamie

2015-08-01

The RAS family of small GTPases is comprised of HRAS, NRAS, and KRAS. KRAS is invariably oncogenically mutated in pancreatic cancers, which is known to induce this disease. Beyond oncogenic KRAS, redox-dependent reactions have been implicated in the activation of the remaining wild-type RAS proteins in pancreatic cancer cell lines. These results suggest a possible involvement of wild-type RAS proteins in pancreatic cancer. To evaluate the impact of genetically suppressing wild-type RAS expression on pancreatic cancer. Hras homozygous null mice (Hras -/- ) were crossed into a Pdx-Cre; LSL-Kras G12D/+ (KC) murine background in which oncogenic Kras is activated in the pancreas to promote preinvasive pancreatic cancer. Tumor burden was then measured at different stages of disease. HRas -/- ;KC mice exhibited more precancerous lesions in the pancreas and more off-target skin papillomas compared to their wild-type counterparts, suggesting that Hras suppresses early oncogenic Kras-driven tumorigenesis, possibly at the time of initiation. Loss of Hras also reduced the survival of mice engineered to develop aggressive pancreatic cancer by the additional disruption of one allele of the tumor suppressor p53 (Trp53 R172H/+ ). However, this survival advantage was lost when both alleles of Trp53 were mutated, suggesting that wild-type Hras inhibits tumorigenesis in a p53-dependent fashion. Loss of wild-type Hras promotes the earliest stages of pancreatic tumorigenesis, and moreover results in more rapid progression of the disease. As such, mechanisms leading to activation of wild-type Ras proteins, including but not limited to redox-dependent reactions, may influence the development of pancreatic cancer. Copyright © 2015. Published by Elsevier B.V.

Association Between Environmental Tobacco Smoke Exposure and the Occurrence of EGFR Mutations and ALK Rearrangements in Never-smokers With Non-Small-cell Lung Cancer: Analyses From a Prospective Multinational ETS Registry.

PubMed

Soo, Ross A; Kubo, Akihito; Ando, Masahiko; Kawaguchi, Tomoya; Ahn, Myung-Ju; Ou, Sai-Hong Ignatius

2017-09-01

Molecular studies have demonstrated actionable driver oncogene alterations are more frequent in never-smokers with non-small-cell lung cancer (NSCLC). The etiology of these driver oncogenes in patients with NSCLC remains unknown, and environmental tobacco smoke (ETS) is a potential cause in these cases. We assembled clinical and genetic information for never-smoker patients with NSCLC accrued in Japan, Korea, Singapore, and the United States. To determine an association between cumulative ETS and activating EGFR mutations or ALK rearrangements, the Mantel extension test was used. Multivariate analysis on activating EGFR and ALK gene rearrangements was performed using the generalized linear mixed model with nations as a random effect. From July 2007 to December 2012, 498 never-smokers with pathologically proven NSCLC were registered and tested for the association between ETS and EGFR and ALK status. EGFR mutations were more frequent in the ever-ETS cohort (58.4%) compared with the never-ETS cohort (39.6%), and the incidence of EGFR mutations was significantly associated with the increment of cumulative ETS (cETS) in female never-smokers (P = .033), whereas the incidence of ALK rearrangements was not significantly different between the ever-ETS and never-ETS cohorts. Odds ratio for EGFR mutations for each 10-year increment in cETS was 1.091 and 0.89 for female and male never-smokers (P = .031 and P = .263, respectively). Increased ETS exposure was closely associated with EGFR mutations in female never-smokers with NSCLC in the expanded multinational cohort. However, the association of ETS and ALK rearrangements in never-smokers with NSCLC was not significant. Copyright © 2017 Elsevier Inc. All rights reserved.

Sequential inductions of the ZEB1 transcription factor caused by mutation of Rb and then Ras proteins are required for tumor initiation and progression.

PubMed

Liu, Yongqing; Sánchez-Tilló, Ester; Lu, Xiaoqin; Huang, Li; Clem, Brian; Telang, Sucheta; Jenson, Alfred B; Cuatrecasas, Miriam; Chesney, Jason; Postigo, Antonio; Dean, Douglas C

2013-04-19

Rb1 restricts cell cycle progression, and it imposes cell contact inhibition to suppress tumor outgrowth. It also triggers oncogene-induced senescence to block Ras mutation. Loss of the Rb1 pathway, which is a hallmark of cancer cells, then provides a permissive environment for Ras mutation, and Ras is sufficient for invasive tumor formation in Rb1 family mutant mouse embryo fibroblasts (MEFs). These results demonstrate that sequential mutation of the Rb1 and Ras pathways comprises a tumor initiation axis. Both Rb1 and Ras regulate expression of the transcription factor ZEB1, thereby linking tumor initiation to the subsequent invasion and metastasis, which is induced by ZEB1. ZEB1 acts in a negative feedback loop to block expression of miR-200, which is thought to facilitate tumor invasion and metastasis. However, ZEB1 also represses cyclin-dependent kinase (cdk) inhibitors to control the cell cycle; its mutation in MEFs leads to induction of these inhibitors and premature senescence. Here, we provide evidence for two sequential inductions of ZEB1 during Ras transformation of MEFs. Rb1 constitutively represses cdk inhibitors, and induction of ZEB1 when the Rb1 pathway is lost is required to maintain this repression, allowing for the classic immortalization and loss of cell contact inhibition seen when the Rb1 pathway is lost. In vivo, we show that this induction of ZEB1 is required for Ras-initiated tumor formation. ZEB1 is then further induced by Ras, beyond the level seen with Rb1 mutation, and this Ras superinduction is required to reach a threshold of ZEB1 sufficient for repression of miR-200 and tumor invasion.

The Significance of Ras Activity in Pancreatic Cancer Initiation

PubMed Central

Logsdon, Craig D.; Lu, Weiqin

2016-01-01

The genetic landscape of pancreatic cancer shows nearly ubiquitous mutations of K-RAS. However, oncogenic K-Rasmt alone is not sufficient to lead to pancreatic ductal adenocarcinoma (PDAC) in either human or in genetically modified adult mouse models. Many stimulants, such as high fat diet, CCK, LPS, PGE2 and others, have physiological effects at low concentrations that are mediated in part through modest increases in K-Ras activity. However, at high concentrations, they induce inflammation that, in the presence of oncogenic K-Ras expression, substantially accelerates PDAC formation. The mechanism involves increased activity of oncogenic K-Rasmt. Unlike what has been proposed in the standard paradigm for the role of Ras in oncogenesis, oncogenic K-Rasmt is now known to not be constitutively active. Rather, it can be activated by standard mechanisms similar to wild-type K-Ras, but its activity is sustained for a prolonged period. Furthermore, if the level of K-Ras activity exceeds a threshold at which it begins to generate its own activators, then a feed-forward loop is formed between K-Ras activity and inflammation and pathological processes including oncogenesis are initiated. Oncogenic K-Rasmt activation, a key event in PDAC initiation and development, is subject to complex regulatory mechanisms. Reagents which inhibit inflammation, such as the Cox2 inhibitor celecoxib, block the feed-forward loop and prevent induction of PDAC in models with endogenous oncogenic K-Rasmt. Increased understanding of the role of activating and inhibitory mechanisms on oncogenic K-Rasmt activity is of paramount importance for the development of preventive and therapeutic strategies to fight against this lethal disease. PMID:26929740

Promoter Methylation in the Genesis of Gastrointestinal Cancer

PubMed Central

Shin, Sung Kwan; Goel, Ajay

2009-01-01

Colorectal cancers (CRC)-and probably all cancers-are caused by alterations in genes. This includes activation of oncogenes and inactivation of tumor suppressor genes (TSGs). There are many ways to achieve these alterations. Oncogenes are frequently activated by point mutation, gene amplification, or changes in the promoter (typically caused by chromosomal rearrangements). TSGs are typically inactivated by mutation, deletion, or promoter methylation, which silences gene expression. About 15% of CRC is associated with loss of the DNA mismatch repair system, and the resulting CRCs have a unique phenotype that is called microsatellite instability, or MSI. This paper reviews the types of genetic alterations that can be found in CRCs and hepatocellular carcinoma (HCC), and focuses upon the epigenetic alterations that result in promoter methylation and the CpG island methylator phenotype (CIMP). The challenge facing CRC research and clinical care at this time is to deal with the heterogeneity and complexity of these genetic and epigenetic alterations, and to use this information to direct rational prevention and treatment strategies. PMID:19568590

Exploring molecular genetics of bladder cancer: lessons learned from mouse models

PubMed Central

Ahmad, Imran; Sansom, Owen J.; Leung, Hing Y.

2012-01-01

Urothelial cell carcinoma (UCC) of the bladder is one of the most common malignancies worldwide, causing considerable morbidity and mortality. It is unusual among the epithelial carcinomas because tumorigenesis can occur by two distinct pathways: low-grade, recurring papillary tumours usually contain oncogenic mutations in FGFR3 or HRAS, whereas high-grade, muscle-invasive tumours with metastatic potential generally have defects in the pathways controlled by the tumour suppressors p53 and retinoblastoma (RB). Over the past 20 years, a plethora of genetically engineered mouse (GEM) models of UCC have been developed, containing deletions or mutations of key tumour suppressor genes or oncogenes. In this review, we provide an up-to-date summary of these GEM models, analyse their flaws and weaknesses, discuss how they have advanced our understanding of UCC at the molecular level, and comment on their translational potential. We also highlight recent studies supporting a role for dysregulated Wnt signalling in UCC and the development of mouse models that recapitulate this dysregulation. PMID:22422829

Targeted Therapies in Non-Small Cell Lung Cancer—Beyond EGFR and ALK

PubMed Central

Rothschild, Sacha I.

2015-01-01

Systemic therapy for non-small cell lung cancer (NSCLC) has undergone a dramatic paradigm shift over the past decade. Advances in our understanding of the underlying biology of NSCLC have revealed distinct molecular subtypes. A substantial proportion of NSCLC depends on oncogenic molecular aberrations (so-called “driver mutations”) for their malignant phenotype. Personalized therapy encompasses the strategy of matching these subtypes with effective targeted therapies. EGFR mutations and ALK translocation are the most effectively targeted oncogenes in NSCLC. EGFR mutations and ALK gene rearrangements are successfully being targeted with specific tyrosine kinase inhibitors. The number of molecular subgroups of NSCLC continues to grow. The scope of this review is to discuss recent data on novel molecular targets as ROS1, BRAF, KRAS, HER2, c-MET, RET, PIK3CA, FGFR1 and DDR2. Thereby the review will focus on therapeutic strategies targeting these aberrations. Moreover, the emerging challenge of acquired resistance to initially effective therapies will be discussed. PMID:26018876

New and Unexpected Biological Functions for the Src-Homology 2 Domain-Containing Phosphatase SHP-2 in the Gastrointestinal Tract.

PubMed

Coulombe, Geneviève; Rivard, Nathalie

2016-01-01

SHP-2 is a tyrosine phosphatase expressed in most embryonic and adult tissues. SHP-2 regulates many cellular functions including growth, differentiation, migration, and survival. Genetic and biochemical evidence show that SHP-2 is required for rat sarcoma viral oncogene/extracellular signal-regulated kinases mitogen-activated protein kinase pathway activation by most tyrosine kinase receptors, as well as by G-protein-coupled and cytokine receptors. In addition, SHP-2 can regulate the Janus kinase/signal transducers and activators of transcription, nuclear factor-κB, phosphatidyl-inositol 3-kinase/Akt, RhoA, Hippo, and Wnt/β-catenin signaling pathways. Emerging evidence has shown that SHP-2 dysfunction represents a key factor in the pathogenesis of gastrointestinal diseases, in particular in chronic inflammation and cancer. Variations within the gene locus encoding SHP-2 have been associated with increased susceptibility to develop ulcerative colitis and gastric atrophy. Furthermore, mice with conditional deletion of SHP-2 in intestinal epithelial cells rapidly develop severe colitis. Similarly, hepatocyte-specific deletion of SHP-2 induces hepatic inflammation, resulting in regenerative hyperplasia and development of tumors in aged mice. However, the SHP-2 gene initially was suggested to be a proto-oncogene because activating mutations of this gene were found in pediatric leukemias and certain forms of liver and colon cancers. Moreover, SHP-2 expression is up-regulated in gastric and hepatocellular cancers. Notably, SHP-2 functions downstream of cytotoxin-associated antigen A (CagA), the major virulence factor of Helicobacter pylori , and is associated with increased risks of gastric cancer. Further compounding this complexity, most recent findings suggest that SHP-2 also coordinates carbohydrate, lipid, and bile acid synthesis in the liver and pancreas. This review aims to summarize current knowledge and recent data regarding the biological functions of SHP-2 in the gastrointestinal tract.

Identification of Nuclear Protein Targets for Six Leukemogenic Tyrosine Kinases Governed by Post-Translational Regulation

PubMed Central

Pierce, Andrew; Williamson, Andrew; Jaworska, Ewa; Griffiths, John R.; Taylor, Sam; Walker, Michael; O’Dea, Mark Aspinall; Spooncer, Elaine; Unwin, Richard D.; Poolman, Toryn; Ray, David; Whetton, Anthony D.

2012-01-01

Mutated tyrosine kinases are associated with a number of different haematological malignancies including myeloproliferative disorders, lymphoma and acute myeloid leukaemia. The potential commonalities in the action of six of these leukemogenic proteins on nuclear proteins were investigated using systematic proteomic analysis. The effects on over 3600 nuclear proteins and 1500 phosphopeptide sites were relatively quantified in seven isogenic cell lines. The effects of the kinases were diverse although some commonalities were found. Comparison of the nuclear proteomic data with transcriptome data and cytoplasmic proteomic data indicated that the major changes are due to post-translational mechanisms rather than changes in mRNA or protein distribution. Analysis of the promoter regions of genes whose protein levels changed in response to the kinases showed the most common binding site found was that for NFκB whilst other sites such as those for the glucocorticoid receptor were also found. Glucocorticoid receptor levels and phosphorylation were decreased by all 6 PTKs. Whilst Glucocorticoid receptor action can potentiate NFκB action those proteins where genes have NFκB binding sites were in often regulated post-translationally. However all 6 PTKs showed evidence of NFkB pathway modulation via activation via altered IkB and NFKB levels. Validation of a common change was also undertaken with PMS2, a DNA mismatch repair protein. PMS2 nuclear levels were decreased in response to the expression of all 6 kinases, with no concomitant change in mRNA level or cytosolic protein level. Response to thioguanine, that requires the mismatch repair pathway, was modulated by all 6 oncogenic kinases. In summary common targets for 6 oncogenic PTKs have been found that are regulated by post-translational mechanisms. They represent potential new avenues for therapies but also demonstrate the post-translational regulation is a key target of leukaemogenic kinases. PMID:22745689

The G1 phase Cdks regulate the centrosome cycle and mediate oncogene-dependent centrosome amplification

PubMed Central

2011-01-01

Because centrosome amplification generates aneuploidy and since centrosome amplification is ubiquitous in human tumors, a strong case is made for centrosome amplification being a major force in tumor biogenesis. Various evidence showing that oncogenes and altered tumor suppressors lead to centrosome amplification and aneuploidy suggests that oncogenes and altered tumor suppressors are a major source of genomic instability in tumors, and that they generate those abnormal processes to initiate and sustain tumorigenesis. We discuss how altered tumor suppressors and oncogenes utilize the cell cycle regulatory machinery to signal centrosome amplification and aneuploidy. PMID:21272329

Oncogenic osteomalacia due to FGF23-expressing colon adenocarcinoma.

PubMed

Leaf, David E; Pereira, Renata C; Bazari, Hasan; Jüppner, Harald

2013-03-01

Oncogenic osteomalacia, a paraneoplastic syndrome associated with hypophosphatemia due to increased urinary phosphate excretion, is caused by excessive synthesis and secretion of fibroblast growth factor 23 (FGF23), a phosphaturic hormone that is normally produced by osteocytes. Most cases of oncogenic osteomalacia have been associated with benign tumors of bone or soft tissue; however, whether malignant neoplasms can also produce and secrete FGF23 is currently unknown. The aim was to determine whether a malignant neoplasm could cause oncogenic osteomalacia through excessive production and secretion of FGF23. We describe an 80-year-old woman with stage IV colon adenocarcinoma who presented with severe hypophosphatemia (0.4 mg/dL; reference, 2.6-4.5 mg/dL). Fractional excretion of phosphate was 34% (reference, <5% in the setting of hypophosphatemia), and plasma levels of FGF23 were highly elevated at 674 RU/mL (reference, <180 RU/mL). Immunohistochemical analysis of the patient's tumor showed strong staining for FGF23. Genetic analyses revealed a point mutation in the KRAS gene. We present the first case in which a malignant neoplasm is documented to produce and secrete FGF23, leading to renal phosphate-wasting. Oncogenic osteomalacia should be considered in the differential diagnosis for patients with a malignant tumor who present with hypophosphatemia.

Oncogenic Osteomalacia due to FGF23-Expressing Colon Adenocarcinoma

PubMed Central

Pereira, Renata C.; Bazari, Hasan; Jüppner, Harald

2013-01-01

Context: Oncogenic osteomalacia, a paraneoplastic syndrome associated with hypophosphatemia due to increased urinary phosphate excretion, is caused by excessive synthesis and secretion of fibroblast growth factor 23 (FGF23), a phosphaturic hormone that is normally produced by osteocytes. Most cases of oncogenic osteomalacia have been associated with benign tumors of bone or soft tissue; however, whether malignant neoplasms can also produce and secrete FGF23 is currently unknown. Objective: The aim was to determine whether a malignant neoplasm could cause oncogenic osteomalacia through excessive production and secretion of FGF23. Setting: We describe an 80-year-old woman with stage IV colon adenocarcinoma who presented with severe hypophosphatemia (0.4 mg/dL; reference, 2.6–4.5 mg/dL). Results: Fractional excretion of phosphate was 34% (reference, <5% in the setting of hypophosphatemia), and plasma levels of FGF23 were highly elevated at 674 RU/mL (reference, <180 RU/mL). Immunohistochemical analysis of the patient's tumor showed strong staining for FGF23. Genetic analyses revealed a point mutation in the KRAS gene. Conclusions: We present the first case in which a malignant neoplasm is documented to produce and secrete FGF23, leading to renal phosphate-wasting. Oncogenic osteomalacia should be considered in the differential diagnosis for patients with a malignant tumor who present with hypophosphatemia. PMID:23393166

Advances in molecular biology of lung disease: aiming for precision therapy in non-small cell lung cancer.

PubMed

Rooney, Claire; Sethi, Tariq

2015-10-01

Lung cancer is the principal cause of cancer-related mortality in the developed world, accounting for almost one-quarter of all cancer deaths. Traditional treatment algorithms have largely relied on histologic subtype and have comprised pragmatic chemotherapy regimens with limited efficacy. However, because our understanding of the molecular basis of disease in non-small cell lung cancer (NSCLC) has improved exponentially, it has become apparent that NSCLC can be radically subdivided, or molecularly characterized, based on recurrent driver mutations occurring in specific oncogenes. We know that the presence of such mutations leads to constitutive activation of aberrant signaling proteins that initiate, progress, and sustain tumorigenesis. This persistence of the malignant phenotype is referred to as "oncogene addiction." On this basis, a paradigm shift in treatment approach has occurred. Rational, targeted therapies have been developed, the first being tyrosine kinase inhibitors (TKIs), which entered the clinical arena > 10 years ago. These were tremendously successful, significantly affecting the natural history of NSCLC and improving patient outcomes. However, the benefits of these drugs are somewhat limited by the emergence of adaptive resistance mechanisms, and efforts to tackle this phenomenon are ongoing. A better understanding of all types of oncogene-driven NSCLC and the occurrence of TKI resistance will help us to further develop second- and third-generation small molecule inhibitors and will expand our range of precision therapies for this disease.

Loss of mutL homolog-1 (MLH1) expression promotes acquisition of oncogenic and inhibitor-resistant point mutations in tyrosine kinases.

PubMed

Springuel, Lorraine; Losdyck, Elisabeth; Saussoy, Pascale; Turcq, Béatrice; Mahon, François-Xavier; Knoops, Laurent; Renauld, Jean-Christophe

2016-12-01

Genomic instability drives cancer progression by promoting genetic abnormalities that allow for the multi-step clonal selection of cells with growth advantages. We previously reported that the IL-9-dependent TS1 cell line sequentially acquired activating substitutions in JAK1 and JAK3 upon successive selections for growth factor independent and JAK inhibitor-resistant cells, suggestive of a defect in mutation avoidance mechanisms. In the first part of this paper, we discovered that the gene encoding mutL homolog-1 (MLH1), a key component of the DNA mismatch repair system, is silenced by promoter methylation in TS1 cells. By means of stable ectopic expression and RNA interference methods, we showed that the high frequencies of growth factor-independent and inhibitor-resistant cells with activating JAK mutations can be attributed to the absence of MLH1 expression. In the second part of this paper, we confirm the clinical relevance of our findings by showing that chronic myeloid leukemia relapses upon ABL-targeted therapy correlated with a lower expression of MLH1 messenger RNA. Interestingly, the mutational profile observed in our TS1 model, characterized by a strong predominance of T:A>C:G transitions, was identical to the one described in the literature for primitive cells derived from chronic myeloid leukemia patients. Taken together, our observations demonstrate for the first time a causal relationship between MLH1-deficiency and incidence of oncogenic point mutations in tyrosine kinases driving cell transformation and acquired resistance to kinase-targeted cancer therapies.

Myeloproliferative neoplasms: Current molecular biology and genetics.

PubMed

Saeidi, Kolsoum

2016-02-01

Myeloproliferative neoplasms (MPNs) are clonal disorders characterized by increased production of mature blood cells. Philadelphia chromosome-negative MPNs (Ph-MPNs) consist of polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). A number of stem cell derived mutations have been identified in the past 10 years. These findings showed that JAK2V617F, as a diagnostic marker involving JAK2 exon 14 with a high frequency, is the best molecular characterization of Ph-MPNs. Somatic mutations in an endoplasmic reticulum chaperone, named calreticulin (CALR), is the second most common mutation in patients with ET and PMF after JAK2 V617F mutation. Discovery of CALR mutations led to the increased molecular diagnostic of ET and PMF up to 90%. It has been shown that JAK2V617F is not the unique event in disease pathogenesis. Some other genes' location such as TET oncogene family member 2 (TET2), additional sex combs-like 1 (ASXL1), casitas B-lineage lymphoma proto-oncogene (CBL), isocitrate dehydrogenase 1/2 (IDH1/IDH2), IKAROS family zinc finger 1 (IKZF1), DNA methyltransferase 3A (DNMT3A), suppressor of cytokine signaling (SOCS), enhancer of zeste homolog 2 (EZH2), tumor protein p53 (TP53), runt-related transcription factor 1 (RUNX1) and high mobility group AT-hook 2 (HMGA2) have also identified to be involved in MPNs phenotypes. Here, current molecular biology and genetic mechanisms involved in MNPs with a focus on the aforementioned factors is presented. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Genomic profiling in a homogeneous molecular subtype of non-small cell lung cancer: An effort to explore new drug targets.

PubMed

Veldore, Vidya H; Patil, S; Satheesh, C T; Shashidhara, H P; Tejaswi, R; Prabhudesai, Shilpa A; Krishnamoorthy, N; Hazarika, D; Naik, R; Rao, Raghavendra M; Ajai Kumar, B S

2015-01-01

Patients' who are positive for kinase domain activating mutations in epidermal growth factor receptor (EGFR) gene, constitute 30-40% of non-small cell lung cancer (NSCLC), and are suitable candidates for Tyrosine Kinase Inhibitor based targeted/personalized therapy. In EGFR non-mutated subset, 8-10% that show molecular abnormalities such as EML4-ALK, ROS1-ALK, KIP4-ALK, may also derive the benefit of targeted therapy. However, 40% of NSCLC belong to a grey zone of tumours that are negative for the clinically approved biomarkers for personalized therapy. This pilot study aims to identify and classify molecular subtypes of this group to address the un-met need for new drug targets in this category. Here we screened for known/novel oncogenic driver mutations using a 46 gene Ampliseq Panel V1.0 that includes Ser/Thr/Tyr kinases, transcription factors and tumor suppressors. NSCLC with tumor burden of at least 40% on histopathology were screened for 29 somatic mutations in the EGFR kinase domain by real-time polymerase chain reaction methods. 20 cases which were EGFR non-mutated for TK domain mutations were included in this study. DNA Quality was verified from each of the 20 cases by fluorimeter, pooled and subjected to targeted re-sequencing in the Ion Torrent platform. Torrent Suite software was used for next generation sequencing raw data processing and variant calling. The clinical relevance and pathological role of all the mutations/variants that include SNPs and Indels was assessed using polyphen-2/SIFT/PROVEAN/mutation assessor structure function prediction programs. There were 10 pathogenic mutations in six different oncogenes for which annotation was available in the COSMIC database; C420R mutation in PIK3CA, Q472H mutation in vascular endothelial growth factor receptor 2 (VEGFR2) (KDR), C630W and C634R in RET, K367M mutation in fibroblast growth factor receptor 2 (FGFR2), G12C in KRAS and 4 pathogenic mutations in TP53 in the DNA binding domain (E285K, R213L, R175H, V173G). Results suggest, a potential role for PIK3CA, VEGFR2, RET and FGFR2 as therapeutic targets in EGFR non-mutated NSCLC that requires further clinical validation.

Characterization of dSnoN and its relationship to Decapentaplegic signaling in Drosophila.

PubMed

Barrio, Rosa; López-Varea, Ana; Casado, Mar; de Celis, Jose F

2007-06-01

Vertebrate members of the ski/snoN family of proto-oncogenes antagonize TGFbeta and BMP signaling in a variety of experimental situations. This activity of Ski/SnoN proteins is related to their ability to interact with Smads, the proteins acting as key mediators of the transcriptional response to the TGFbeta superfamily members. However, despite extensive efforts to identify the physiological roles of the Ski/SnoN proteins, it is not yet clear whether they participate in regulating Activin and/or BMP signaling during normal development. It is therefore crucial to examine their roles in vivo mostly because of the large number of known Ski/SnoN-interacting proteins and the association between the up-regulation of these genes and cancer progression. Here we characterize the Drosophila homolog to vertebrate ski and snoN genes. The Drosophila dSnoN protein retains the ability of its vertebrate counterparts to antagonize BMP signaling in vivo and in cultured cells. dSnoN does not interfere with Mad phosphorylation but it interacts genetically with Mad, Medea and dSmad2. Mutations in either the Smad2-3 or Smad4 putative binding sites of dSnoN prevent the antagonism of dSnoN towards Dpp signaling, although homozygous flies for these mutations or for a genetic deficiency of the locus are viable and have wings of normal size and pattern.

Akt SUMOylation regulates cell proliferation and tumorigenesis.

PubMed

Li, Rong; Wei, Jie; Jiang, Cong; Liu, Dongmei; Deng, Lu; Zhang, Kai; Wang, Ping

2013-09-15

Proto-oncogene Akt plays essential roles in cell proliferation and tumorigenesis. Full activation of Akt is regulated by phosphorylation, ubiquitination, and acetylation. Here we report that SUMOylation of Akt is a novel mechanism for its activation. Systematically analyzing the role of lysine residues in Akt activation revealed that K276, which is located in a SUMOylation consensus motif, is essential for Akt activation. Ectopic or endogenous Akt1 could be modified by SUMOylation. RNA interference-mediated silencing of UBC9 reduced Akt SUMOylation, which was promoted by SUMO E3 ligase PIAS1 and reversed by the SUMO-specific protease SENP1. Although multiple sites on Akt could be SUMOylated, K276 was identified as a major SUMO acceptor site. K276R or E278A mutation reduced SUMOylation of Akt but had little effect on its ubiquitination. Strikingly, these mutations also completely abolished Akt kinase activity. In support of these results, we found that expression of PIAS1 and SUMO1 increased Akt activity, whereas expression of SENP1 reduced Akt1 activity. Interestingly, the cancer-derived mutant E17K in Akt1 that occurs in various cancers was more efficiently SUMOylated than wild-type Akt. Moreover, SUMOylation loss dramatically reduced Akt1 E17K-mediated cell proliferation, cell migration, and tumorigenesis. Collectively, our findings establish that Akt SUMOylation provides a novel regulatory mechanism for activating Akt function. ©2013 AACR.

The Role of c-FLIP(L) in Regulating Apoptotic Pathways in Prostate Cancer

DTIC Science & Technology

2006-12-01

which regulates gene expression 3. c-Fos has been shown to play an important role in development, inflammation and oncogenic processes. For example...important role in development, inflammation and oncogenic processes. For example, TNF-family induction of c-Fos plays an important role in proper bone c...identifying the down-stream targets of c-Fos has significant implications in understanding of normal development, inflammation and oncogenesis (10). In

Mutational landscape of a chemically-induced mouse model of liver cancer.

PubMed

Connor, Frances; Rayner, Tim F; Aitken, Sarah J; Feig, Christine; Lukk, Margus; Santoyo-Lopez, Javier; Odom, Duncan T

2018-06-26

Carcinogen-induced mouse models of liver cancer are used extensively to study pathogenesis of the disease and have a critical role in validating candidate therapeutics. These models can recapitulate molecular and histological features of human disease. However, it is not known if the genomic alterations driving these mouse tumour genomes are comparable to those found in human tumours. Here, we provide a detailed genomic characterisation of tumours from a commonly used mouse model of hepatocellular carcinoma (HCC). We analysed whole exome sequences of liver tumours arising in mice exposed to diethylnitrosamine (DEN). DEN-initiated tumours had a high, uniform number of somatic single nucleotide variants (SNVs), with few insertions, deletions or copy number alterations, consistent with the known genotoxic action of DEN. Exposure of hepatocytes to DEN left a reproducible mutational imprint in resulting tumour exomes which we could computationally reconstruct using six known COSMIC mutational signatures. The tumours carried a high diversity of low-incidence, non-synonymous point mutations in many oncogenes and tumour suppressors, reflecting the stochastic introduction of SNVs into the hepatocyte genome by the carcinogen. We identified four recurrently mutated genes that were putative oncogenic drivers of HCC in this model. Every neoplasm carried activating hotspot mutations either in codon 61 of Hras, in codon 584 of Braf or in codon 254 of Egfr. Truncating mutations of Apc occurred in 21% of neoplasms, which were exclusively carcinomas supporting a role for deregulation of Wnt/β-catenin signalling in cancer progression. Our study provides detailed insight into the mutational landscape of tumours arising in a commonly-used carcinogen model of HCC, facilitating the future use of this model to understand the human disease. Mouse models are widely used to study the biology of cancer and to test potential therapies. Here, we have described the mutational landscape of tumours arising in a carcinogen-induced mouse model of liver cancer. Since cancer is a disease caused by genomic alterations, information about the patterns and types of mutations in the tumours in this mouse model should facilitate its use to study human liver cancer. Copyright © 2018 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

KIT mutations in Russian patients with mucosal melanoma.

PubMed

Abysheva, Svetlana N; Iyevleva, Aglaya G; Efimova, Nina V; Mokhina, Yulia B; Sabirova, Feruza A; Ivantsov, Alexandr O; Artemieva, Anna S; Togo, Alexandr V; Moiseyenko, Vladimir M; Matsko, Dmitry E; Imyanitov, Evgeny N

2011-12-01

A single institution series of 48 mucosal melanomas (MMs) has been analyzed for the presence of KIT mutations using high-resolution melting and sequencing of abnormally melted DNA fragments. The analysis of exons 9, 11, 13, and 17 has revealed eight of 48 (17%) nonsynonymous alterations, including zero of seven head and neck, six of 24 anorectal, one of 15 genitourinary, one of one gastric, and zero of one mediastinal MMs. Seven of these mutations were potentially associated with the tumor sensitivity to KIT tyrosine kinase inhibitors. One tumor harbored somatically acquired silent nucleotide substitution c.1383A>G (T461T). This study adds to the evidence that a substantial portion of MMs carry a therapeutically relevant mutation in the KIT oncogene.

Retroviral expression screening of oncogenes in natural killer cell leukemia.

PubMed

Choi, Young Lim; Moriuchi, Ryozo; Osawa, Mitsujiro; Iwama, Atsushi; Makishima, Hideki; Wada, Tomoaki; Kisanuki, Hiroyuki; Kaneda, Ruri; Ota, Jun; Koinuma, Koji; Ishikawa, Madoka; Takada, Shuji; Yamashita, Yoshihiro; Oshimi, Kazuo; Mano, Hiroyuki

2005-08-01

Aggressive natural killer cell leukemia (ANKL) is an intractable malignancy that is characterized by the outgrowth of NK cells. To identify transforming genes in ANKL, we constructed a retroviral cDNA expression library from an ANKL cell line KHYG-1. Infection of 3T3 cells with recombinant retroviruses yielded 33 transformed foci. Nucleotide sequencing of the DNA inserts recovered from these foci revealed that 31 of them encoded KRAS2 with a glycine-to-alanine mutation at codon 12. Mutation-specific PCR analysis indicated that the KRAS mutation was present only in KHYG-1 cells, not in another ANKL cell line or in clinical specimens (n=8).

Recurrent papillary craniopharyngioma with BRAFV600E mutation treated with neoadjuvant-targeted therapy.

PubMed

Rostami, Elham; Witt Nyström, Petra; Libard, Sylwia; Wikström, Johan; Casar-Borota, Olivera; Gudjonsson, Olafur

2017-11-01

Craniopharyngiomas are histologically benign but locally aggressive tumors in the sellar region that may cause devastating neurological and endocrine deficits. They tend to recur following surgery with high morbidity; hence, postoperative radiotherapy is recommended following sub-total resection. BRAFV600E mutation is the principal oncogenic driver in the papillary variant of craniopharyngiomas. Recently, a dramatic tumor reduction has been reported in a patient with BRAFV600E mutated, multiply recurrent papillary craniopharyngioma using a combination therapy of BRAF inhibitor dabrafenib and MEK inhibitor trametinib. Here, we report on near-radical reduction of a growing residual BRAFV600E craniopharyngioma using the same neoadjuvant therapy.

Cell Cycle Deregulation in Ewing's Sarcoma Pathogenesis

PubMed Central

Kowalewski, Ashley A.; Randall, R. Lor; Lessnick, Stephen L.

2011-01-01

Ewing's sarcoma is a highly aggressive pediatric tumor of bone that usually contains the characteristic chromosomal translocation t(11;22)(q24;q12). This translocation encodes the oncogenic fusion protein EWS/FLI, which acts as an aberrant transcription factor to deregulate target genes necessary for oncogenesis. One key feature of oncogenic transformation is dysregulation of cell cycle control. It is therefore likely that EWS/FLI and other cooperating mutations in Ewing's sarcoma modulate the cell cycle to facilitate tumorigenesis. This paper will summarize current published data associated with deregulation of the cell cycle in Ewing's sarcoma and highlight important questions that remain to be answered. PMID:21052502

Mutations in the PP2A regulatory subunit B family genes PPP2R5B, PPP2R5C and PPP2R5D cause human overgrowth.

PubMed

Loveday, Chey; Tatton-Brown, Katrina; Clarke, Matthew; Westwood, Isaac; Renwick, Anthony; Ramsay, Emma; Nemeth, Andrea; Campbell, Jennifer; Joss, Shelagh; Gardner, McKinlay; Zachariou, Anna; Elliott, Anna; Ruark, Elise; van Montfort, Rob; Rahman, Nazneen

2015-09-01

Overgrowth syndromes comprise a group of heterogeneous disorders characterised by excessive growth parameters, often in association with intellectual disability. To identify new causes of human overgrowth, we have been undertaking trio-based exome sequencing studies in overgrowth patients and their unaffected parents. Prioritisation of functionally relevant genes with multiple unique de novo mutations revealed four mutations in protein phosphatase 2A (PP2A) regulatory subunit B family genes protein phosphatase 2, regulatory Subunit B', beta (PPP2R5B); protein phosphatase 2, regulatory Subunit B', gamma (PPP2R5C); and protein phosphatase 2, regulatory Subunit B', delta (PPP2R5D). This observation in 3 related genes in 111 individuals with a similar phenotype is greatly in excess of the expected number, as determined from gene-specific de novo mutation rates (P = 1.43 × 10(-10)). Analysis of exome-sequencing data from a follow-up series of overgrowth probands identified a further pathogenic mutation, bringing the total number of affected individuals to 5. Heterozygotes shared similar phenotypic features including increased height, increased head circumference and intellectual disability. The mutations clustered within a region of nine amino acid residues in the aligned protein sequences (P = 1.6 × 10(-5)). We mapped the mutations onto the crystal structure of the PP2A holoenzyme complex to predict their molecular and functional consequences. These studies suggest that the mutations may affect substrate binding, thus perturbing the ability of PP2A to dephosphorylate particular protein substrates. PP2A is a major negative regulator of v-akt murine thymoma viral oncogene homolog 1 (AKT). Thus, our data further expand the list of genes encoding components of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/AKT signalling cascade that are disrupted in human overgrowth conditions. © The Author 2015. Published by Oxford University Press.

PTEN: Multiple Functions in Human Malignant Tumors.

PubMed

Milella, Michele; Falcone, Italia; Conciatori, Fabiana; Cesta Incani, Ursula; Del Curatolo, Anais; Inzerilli, Nicola; Nuzzo, Carmen M A; Vaccaro, Vanja; Vari, Sabrina; Cognetti, Francesco; Ciuffreda, Ludovica

2015-01-01

PTEN is the most important negative regulator of the PI3K signaling pathway. In addition to its canonical, PI3K inhibition-dependent functions, PTEN can also function as a tumor suppressor in a PI3K-independent manner. Indeed, the PTEN network regulates a broad spectrum of biological functions, modulating the flow of information from membrane-bound growth factor receptors to nuclear transcription factors, occurring in concert with other tumor suppressors and oncogenic signaling pathways. PTEN acts through its lipid and protein phosphatase activity and other non-enzymatic mechanisms. Studies conducted over the past 10 years have expanded our understanding of the biological role of PTEN, showing that in addition to its ability to regulate proliferation and cell survival, it also plays an intriguing role in regulating genomic stability, cell migration, stem cell self-renewal, and tumor microenvironment. Changes in PTEN protein levels, location, and enzymatic activity through various molecular mechanisms can generate a continuum of functional PTEN levels in inherited syndromes, sporadic cancers, and other diseases. PTEN activity can indeed, be modulated by mutations, epigenetic silencing, transcriptional repression, aberrant protein localization, and post-translational modifications. This review will discuss our current understanding of the biological role of PTEN, how PTEN expression and activity are regulated, and the consequences of PTEN dysregulation in human malignant tumors.

PTEN: Multiple Functions in Human Malignant Tumors

PubMed Central

Milella, Michele; Falcone, Italia; Conciatori, Fabiana; Cesta Incani, Ursula; Del Curatolo, Anais; Inzerilli, Nicola; Nuzzo, Carmen M. A.; Vaccaro, Vanja; Vari, Sabrina; Cognetti, Francesco; Ciuffreda, Ludovica

2015-01-01

PTEN is the most important negative regulator of the PI3K signaling pathway. In addition to its canonical, PI3K inhibition-dependent functions, PTEN can also function as a tumor suppressor in a PI3K-independent manner. Indeed, the PTEN network regulates a broad spectrum of biological functions, modulating the flow of information from membrane-bound growth factor receptors to nuclear transcription factors, occurring in concert with other tumor suppressors and oncogenic signaling pathways. PTEN acts through its lipid and protein phosphatase activity and other non-enzymatic mechanisms. Studies conducted over the past 10 years have expanded our understanding of the biological role of PTEN, showing that in addition to its ability to regulate proliferation and cell survival, it also plays an intriguing role in regulating genomic stability, cell migration, stem cell self-renewal, and tumor microenvironment. Changes in PTEN protein levels, location, and enzymatic activity through various molecular mechanisms can generate a continuum of functional PTEN levels in inherited syndromes, sporadic cancers, and other diseases. PTEN activity can indeed, be modulated by mutations, epigenetic silencing, transcriptional repression, aberrant protein localization, and post-translational modifications. This review will discuss our current understanding of the biological role of PTEN, how PTEN expression and activity are regulated, and the consequences of PTEN dysregulation in human malignant tumors. PMID:25763354

microRNA-218 inhibits prostate cancer cell growth and promotes apoptosis by repressing TPD52 expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Guangye, E-mail: guangyehan@126.com; Fan, Maochuan, E-mail: maochunfan@outlook.com; Zhang, Xinjun, E-mail: xinjunzhang11@163.com

2015-01-16

Highlights: • miR-218 expression is downregulated in prostate cancer. • miR-218 inhibits prostate tumor cells proliferation partially through promoting apoptosis. • miR-218 targets TPD52 by binding to its 3′-UTR. • miR-218 suppresses prostate cancer cell growth through inhibiting TPD52 expression. - Abstract: The tumor protein D52 (TPD52) is an oncogene overexpressed in prostate cancer (PC) due to gene amplification. Although the oncogenic effect of TPD52 is well recognized, how its expression is regulated is still not clear. This study tried to explore the regulative role of miR-218, a tumor suppressing miRNA on TPD52 expression and prostate cancer cell proliferation. Wemore » found the expression of miR-218 was significantly lower in PC specimens. Based on gain and loss of function analysis, we found miR-218 significantly inhibit cancer cell proliferation by inducing apoptosis. These results strongly suggest that miR-218 plays a tumor suppressor role in PC cells. In addition, our data firstly demonstrated that miR-218 directly regulates oncogenic TPD52 in PC3 cells and the miR-218-TPD52 axis can regulate growth of this prostate cancer cell line. Knockdown of TPD52 resulted in significantly increased cancer cell apoptosis. Clearly understanding of oncogenic TPD52 pathways regulated by miR-218 might be helpful to reveal new therapeutic targets for PC.« less

hEcd, A Novel Regulator of Mammary Epithelial Cell Survival

DTIC Science & Technology

2009-09-01

theYeast Two hybrid analysis with human papilloma virus oncogene E6 (the most efficient oncogene to immortalize hMECs in vitro) as a bait and mammary...transformation. We have identified a novel protein us ing the Yeast Two hybrid analysis with human papilloma virus oncogene E6 (the most efficient...epithelial cell cDNA library, we identified hEcd ( human orthologue of Drosophila Ecdysoneless) as a novel E6 binding partner. To study the cellular

Identification of significantly mutated regions across cancer types highlights a rich landscape of functional molecular alterations

PubMed Central

Araya, Carlos L.; Cenik, Can; Reuter, Jason A.; Kiss, Gert; Pande, Vijay S.; Snyder, Michael P.; Greenleaf, William J.

2015-01-01

Cancer sequencing studies have primarily identified cancer-driver genes by the accumulation of protein-altering mutations. An improved method would be annotation-independent, sensitive to unknown distributions of functions within proteins, and inclusive of non-coding drivers. We employed density-based clustering methods in 21 tumor types to detect variably-sized significantly mutated regions (SMRs). SMRs reveal recurrent alterations across a spectrum of coding and non-coding elements, including transcription factor binding sites and untranslated regions mutated in up to ∼15% of specific tumor types. SMRs reveal spatial clustering of mutations at molecular domains and interfaces, often with associated changes in signaling. Mutation frequencies in SMRs demonstrate that distinct protein regions are differentially mutated among tumor types, as exemplified by a linker region of PIK3CA in which biophysical simulations suggest mutations affect regulatory interactions. The functional diversity of SMRs underscores both the varied mechanisms of oncogenic misregulation and the advantage of functionally-agnostic driver identification. PMID:26691984

Selective Inhibition of Tumor Oncogenes by Disruption of Super-Enhancers

PubMed Central

Lovén, Jakob; Hoke, Heather A.; Lin, Charles Y.; Lau, Ashley; Orlando, David A.; Vakoc, Christopher R.; Bradner, James E.; Lee, Tong Ihn; Young, Richard A.

2013-01-01

Summary Chromatin regulators have become attractive targets for cancer therapy, but it is unclear why inhibition of these ubiquitous regulators should have gene-specific effects in tumor cells. Here, we investigate how inhibition of the widely expressed transcriptional coactivator BRD4 leads to selective inhibition of the MYC oncogene in multiple myeloma (MM). BRD4 and Mediator were found to co-occupy thousands of enhancers associated with active genes. They also co-occupied a small set of exceptionally large super-enhancers associated with genes that feature prominently in MM biology, including the MYC oncogene. Treatment of MM tumor cells with the BET-bromodomain inhibitor JQ1 led to preferential loss of BRD4 at super-enhancers and consequent transcription elongation defects that preferentially impacted genes with super-enhancers, including MYC. Super-enhancers were found at key oncogenic drivers in many other tumor cells. These observations have implications for the discovery of cancer therapeutics directed at components of super-enhancers in diverse tumor types. PMID:23582323

Mutations in the Nucleolar Phosphoprotein, Nucleophosmin, Promote the Expression of the Oncogenic Transcription Factor MEF/ELF4 in Leukemia Cells and Potentiates Transformation*

PubMed Central

Ando, Koji; Tsushima, Hideki; Matsuo, Emi; Horio, Kensuke; Tominaga-Sato, Shinya; Imanishi, Daisuke; Imaizumi, Yoshitaka; Iwanaga, Masako; Itonaga, Hidehiro; Yoshida, Shinichiro; Hata, Tomoko; Moriuchi, Ryozo; Kiyoi, Hitoshi; Nimer, Stephen; Mano, Hiroyuki; Naoe, Tomoki; Tomonaga, Masao; Miyazaki, Yasushi

2013-01-01

Myeloid ELF1-like factor (MEF/ELF4), a member of the ETS transcription factors, can function as an oncogene in murine cancer models and is overexpressed in various human cancers. Here, we report a mechanism by which MEF/ELF4 may be activated by a common leukemia-associated mutation in the nucleophosmin gene. By using a tandem affinity purification assay, we found that MEF/ELF4 interacts with multifactorial protein nucleophosmin (NPM1). Coimmunoprecipitation and GST pull-down experiments demonstrated that MEF/ELF4 directly forms a complex with NPM1 and also identified the region of NPM1 that is responsible for this interaction. Functional analyses showed that wild-type NPM1 inhibited the DNA binding and transcriptional activity of MEF/ELF4 on the HDM2 promoter, whereas NPM1 mutant protein (Mt-NPM1) enhanced these activities of MEF/ELF4. Induction of Mt-NPM1 into MEF/ELF4-overexpressing NIH3T3 cells facilitated malignant transformation. In addition, clinical leukemia samples with NPM1 mutations had higher human MDM2 (HDM2) mRNA expression. Our data suggest that enhanced HDM2 expression induced by mutant NPM1 may have a role in MEF/ELF4-dependent leukemogenesis. PMID:23393136

Mutations in the nucleolar phosphoprotein, nucleophosmin, promote the expression of the oncogenic transcription factor MEF/ELF4 in leukemia cells and potentiates transformation.

PubMed

Ando, Koji; Tsushima, Hideki; Matsuo, Emi; Horio, Kensuke; Tominaga-Sato, Shinya; Imanishi, Daisuke; Imaizumi, Yoshitaka; Iwanaga, Masako; Itonaga, Hidehiro; Yoshida, Shinichiro; Hata, Tomoko; Moriuchi, Ryozo; Kiyoi, Hitoshi; Nimer, Stephen; Mano, Hiroyuki; Naoe, Tomoki; Tomonaga, Masao; Miyazaki, Yasushi

2013-03-29

Myeloid ELF1-like factor (MEF/ELF4), a member of the ETS transcription factors, can function as an oncogene in murine cancer models and is overexpressed in various human cancers. Here, we report a mechanism by which MEF/ELF4 may be activated by a common leukemia-associated mutation in the nucleophosmin gene. By using a tandem affinity purification assay, we found that MEF/ELF4 interacts with multifactorial protein nucleophosmin (NPM1). Coimmunoprecipitation and GST pull-down experiments demonstrated that MEF/ELF4 directly forms a complex with NPM1 and also identified the region of NPM1 that is responsible for this interaction. Functional analyses showed that wild-type NPM1 inhibited the DNA binding and transcriptional activity of MEF/ELF4 on the HDM2 promoter, whereas NPM1 mutant protein (Mt-NPM1) enhanced these activities of MEF/ELF4. Induction of Mt-NPM1 into MEF/ELF4-overexpressing NIH3T3 cells facilitated malignant transformation. In addition, clinical leukemia samples with NPM1 mutations had higher human MDM2 (HDM2) mRNA expression. Our data suggest that enhanced HDM2 expression induced by mutant NPM1 may have a role in MEF/ELF4-dependent leukemogenesis.

Structural centrosome aberrations sensitize polarized epithelia to basal cell extrusion.

PubMed

Ganier, Olivier; Schnerch, Dominik; Nigg, Erich A

2018-06-01

Centrosome aberrations disrupt tissue architecture and may confer invasive properties to cancer cells. Here we show that structural centrosome aberrations, induced by overexpression of either Ninein-like protein (NLP) or CEP131/AZI1, sensitize polarized mammalian epithelia to basal cell extrusion. While unperturbed epithelia typically dispose of damaged cells through apical dissemination into luminal cavities, certain oncogenic mutations cause a switch in directionality towards basal cell extrusion, raising the potential for metastatic cell dissemination. Here we report that NLP-induced centrosome aberrations trigger the preferential extrusion of damaged cells towards the basal surface of epithelial monolayers. This switch in directionality from apical to basal dissemination coincides with a profound reorganization of the microtubule cytoskeleton, which in turn prevents the contractile ring repositioning that is required to support extrusion towards the apical surface. While the basal extrusion of cells harbouring NLP-induced centrosome aberrations requires exogenously induced cell damage, structural centrosome aberrations induced by excess CEP131 trigger the spontaneous dissemination of dying cells towards the basal surface from MDCK cysts. Thus, similar to oncogenic mutations, structural centrosome aberrations can favour basal extrusion of damaged cells from polarized epithelia. Assuming that additional mutations may promote cell survival, this process could sensitize epithelia to disseminate potentially metastatic cells. © 2018 The Authors.

KRAS Mutation Status Is Not a Predictor for Tumor Response and Survival in Rectal Cancer Patients Who Received Preoperative Radiotherapy With 5-Fluoropyrimidine Followed by Curative Surgery.

PubMed

Lee, Jeong Won; Lee, Jong Hoon; Shim, Byoung Yong; Kim, Sung Hwan; Chung, Mi-Joo; Kye, Bong-Hyeon; Kim, Hyung Jin; Cho, Hyeon Min; Jang, Hong Seok

2015-08-01

We evaluated the tumor response and survival according to the KRAS oncogene status in locally advanced rectal cancer. One hundred patients with locally advanced rectal cancer (cT3-4N0-2M0) received preoperative radiation of 50.4 Gy in 28 fractions with 5-fluorouracil and total mesorectal excision. Tumor DNA from each patient was obtained from pretreatment biopsy tissues. A Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation was found in 26 (26%) of the 100 patients. Downstaging (ypT0-2N0M0) rates after preoperative chemoradiotheray were not statistically different between the wild-type and mutant-type KRAS groups (30.8% vs 27.0%, P = 0.715, respectively). After a median follow-up time of 34 months, there was no statistically significant difference in the 3-year relapse-free survival (82.2% vs 82.6%, P = 0.512) and overall survival (94.7% vs 92.3%, P = 0.249) rates between wild-type and mutant-type KRAS groups, respectively. The KRAS mutation status does not influence the tumor response to the radiotherapy and survival in locally advanced rectal cancer patients who received preoperative chemoradiotherapy and curative surgery.

KRAS Mutation Status Is Not a Predictor for Tumor Response and Survival in Rectal Cancer Patients Who Received Preoperative Radiotherapy With 5-Fluoropyrimidine Followed by Curative Surgery

PubMed Central

Lee, Jeong Won; Lee, Jong Hoon; Shim, Byoung Yong; Kim, Sung Hwan; Chung, Mi-Joo; Kye, Bong-Hyeon; Kim, Hyung Jin; Cho, Hyeon Min; Jang, Hong Seok

2015-01-01

Abstract We evaluated the tumor response and survival according to the KRAS oncogene status in locally advanced rectal cancer. One hundred patients with locally advanced rectal cancer (cT3-4N0-2M0) received preoperative radiation of 50.4 Gy in 28 fractions with 5-fluorouracil and total mesorectal excision. Tumor DNA from each patient was obtained from pretreatment biopsy tissues. A Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation was found in 26 (26%) of the 100 patients. Downstaging (ypT0-2N0M0) rates after preoperative chemoradiotheray were not statistically different between the wild-type and mutant-type KRAS groups (30.8% vs 27.0%, P = 0.715, respectively). After a median follow-up time of 34 months, there was no statistically significant difference in the 3-year relapse-free survival (82.2% vs 82.6%, P = 0.512) and overall survival (94.7% vs 92.3%, P = 0.249) rates between wild-type and mutant-type KRAS groups, respectively. The KRAS mutation status does not influence the tumor response to the radiotherapy and survival in locally advanced rectal cancer patients who received preoperative chemoradiotherapy and curative surgery. PMID:26252300

Time-course Interactions between Cell Proliferation and DNA Sequence Variants in a Mouse Model of Latent Carcinogenicity

EPA Science Inventory

A fundamental principle of non-mutagenic chemical carcinogenesis is that increased cell proliferation enhances spontaneous DNA damage. Over time, this damage drives mutations in oncogenic genes that ultimately lead to cancer. This concept is a central part of cancer mode of actio...

A Molecular Basis of Cancer.

ERIC Educational Resources Information Center

Weinberg, Robert A.

1983-01-01

Discusses the molecular basis of cancer, focusing on genetics of the disease. Indicates that human cancers are initiated by oncogenes (altered versions of normal genes) and that in one case the critical alteration is a single point mutation that changes one amino acid in the protein encoded by the gene. (JN)

Mutation of the Salt Bridge-forming Residues in the ETV6-SAM Domain Interface Blocks ETV6-NTRK3-induced Cellular Transformation*

PubMed Central

Cetinbas, Naniye; Huang-Hobbs, Helen; Tognon, Cristina; Leprivier, Gabriel; An, Jianghong; McKinney, Steven; Bowden, Mary; Chow, Connie; Gleave, Martin; McIntosh, Lawrence P.; Sorensen, Poul H.

2013-01-01

The ETV6-NTRK3 (EN) chimeric oncogene is expressed in diverse tumor types. EN is generated by a t(12;15) translocation, which fuses the N-terminal SAM (sterile α-motif) domain of the ETV6 (or TEL) transcription factor to the C-terminal PTK (protein-tyrosine kinase) domain of the neurotrophin-3 receptor NTRK3. SAM domain-mediated polymerization of EN leads to constitutive activation of the PTK domain and constitutive signaling of the Ras-MAPK and PI3K-Akt pathways, which are essential for EN oncogenesis. Here we show through complementary biophysical and cellular biological techniques that mutation of Lys-99, which participates in a salt bridge at the SAM polymer interface, reduces self-association of the isolated SAM domain as well as high molecular mass complex formation of EN and abrogates the transformation activity of EN. We also show that mutation of Asp-101, the intermolecular salt bridge partner of Lys-99, similarly blocks transformation of NIH3T3 cells by EN, reduces EN tyrosine phosphorylation, inhibits Akt and Mek1/2 signaling downstream of EN, and abolishes tumor formation in nude mice. In contrast, mutations of Glu-100 and Arg-103, residues in the vicinity of the interdomain Lys-99–Asp-101 salt bridge, have little or no effect on these oncogenic characteristics of EN. Our results underscore the importance of specific electrostatic interactions for SAM polymerization and EN transformation. PMID:23798677

Mutation of the salt bridge-forming residues in the ETV6-SAM domain interface blocks ETV6-NTRK3-induced cellular transformation.

PubMed

Cetinbas, Naniye; Huang-Hobbs, Helen; Tognon, Cristina; Leprivier, Gabriel; An, Jianghong; McKinney, Steven; Bowden, Mary; Chow, Connie; Gleave, Martin; McIntosh, Lawrence P; Sorensen, Poul H

2013-09-27

The ETV6-NTRK3 (EN) chimeric oncogene is expressed in diverse tumor types. EN is generated by a t(12;15) translocation, which fuses the N-terminal SAM (sterile α-motif) domain of the ETV6 (or TEL) transcription factor to the C-terminal PTK (protein-tyrosine kinase) domain of the neurotrophin-3 receptor NTRK3. SAM domain-mediated polymerization of EN leads to constitutive activation of the PTK domain and constitutive signaling of the Ras-MAPK and PI3K-Akt pathways, which are essential for EN oncogenesis. Here we show through complementary biophysical and cellular biological techniques that mutation of Lys-99, which participates in a salt bridge at the SAM polymer interface, reduces self-association of the isolated SAM domain as well as high molecular mass complex formation of EN and abrogates the transformation activity of EN. We also show that mutation of Asp-101, the intermolecular salt bridge partner of Lys-99, similarly blocks transformation of NIH3T3 cells by EN, reduces EN tyrosine phosphorylation, inhibits Akt and Mek1/2 signaling downstream of EN, and abolishes tumor formation in nude mice. In contrast, mutations of Glu-100 and Arg-103, residues in the vicinity of the interdomain Lys-99-Asp-101 salt bridge, have little or no effect on these oncogenic characteristics of EN. Our results underscore the importance of specific electrostatic interactions for SAM polymerization and EN transformation.

Familial Breast/Ovarian Cancer and BRCA1/2 Genetic Screening: The Role of Immunohistochemistry as an Additional Method in the Selection of Patients

PubMed Central

Vaz, Fátima H.; Machado, Patrícia M.; Brandão, Rita D.; Laranjeira, Cátia T.; Eugénio, Joana S.; Fernandes, Aires H.; André, Saudade P.

2007-01-01

Only 20–25% of families screened for BRCA1/2 mutations are found positive. Because only a positive result is informative, we studied the role of BRCA1/2 immunohistochemistry as an additional method for patient selection. From 53 high-risk-affected probands, 18 (34%) had available paraffin blocks of their tumors and were selected for this study. Mutation screening was done by conformation-sensitive gel electrophoresis and multiplex ligation-dependent probe amplification. For immunohistochemistry, 21 neoplastic specimens (15 breast carcinomas, 5 ovary neoplasms, and 1 rectal adenocarcinoma) were analyzed with BRCA1 (monoclonal antibody, Ab-1, oncogene) and BRCA2 (polyclonal antibody, Ab-2, oncogene) antibodies. Absence of the BRCA1 protein was confirmed in negative tumors by Western blotting. Seven patients were positive for BRCA1/2 mutations: 5 for BRCA1 and 2 for BRCA2. Four out of five positive patients had tumors negative for BRCA1 immunostaining, and the remaining 13 BRCA1-negative patients had positive BRCA1 immunostaining in all tumor samples. Sensitivity to predict for BRCA1 mutation carriers was 80%, and specificity was 100%, with a positive predictive value of 100% and a negative predictive value of 93%. This correlation was statistically significant (p=0.001). No correlation was observed for BRCA2. If larger studies confirm these results, high-risk patients with BRCA1-negative tumors should be screened first for this gene. PMID:17625228

Quantifying EGFR alterations in the lung cancer genome with nanofluidic digital PCR arrays.

PubMed

Wang, Jun; Ramakrishnan, Ramesh; Tang, Zhe; Fan, Weiwen; Kluge, Amy; Dowlati, Afshin; Jones, Robert C; Ma, Patrick C

2010-04-01

The EGFR [epidermal growth factor receptor (erythroblastic leukemia viral (v-erb-b) oncogene homolog, avian)] gene is known to harbor genomic alterations in advanced lung cancer involving gene amplification and kinase mutations that predict the clinical response to EGFR-targeted inhibitors. Methods for detecting such molecular changes in lung cancer tumors are desirable. We used a nanofluidic digital PCR array platform and 16 cell lines and 20 samples of genomic DNA from resected tumors (stages I-III) to quantify the relative numbers of copies of the EGFR gene and to detect mutated EGFR alleles in lung cancer. We assessed the relative number of EGFR gene copies by calculating the ratio of the number of EGFR molecules (measured with a 6-carboxyfluorescein-labeled Scorpion assay) to the number of molecules of the single-copy gene RPP30 (ribonuclease P/MRP 30kDa subunit) (measured with a 6-carboxy-X-rhodamine-labeled TaqMan assay) in each panel. To assay for the EGFR L858R (exon 21) mutation and exon 19 in-frame deletions, we used the ARMS and Scorpion technologies in a DxS/Qiagen EGFR29 Mutation Test Kit for the digital PCR array. The digital array detected and quantified rare gefitinib/erlotinib-sensitizing EGFR mutations (0.02%-9.26% abundance) that were present in formalin-fixed, paraffin-embedded samples of early-stage resectable lung tumors without an associated increase in gene copy number. Our results also demonstrated the presence of intratumor molecular heterogeneity for the clinically relevant EGFR mutated alleles in these early-stage lung tumors. The digital PCR array platform allows characterization and quantification of oncogenes, such as EGFR, at the single-molecule level. Use of this nanofluidics platform may provide deeper insight into the specific roles of clinically relevant kinase mutations during different stages of lung tumor progression and may be useful in predicting the clinical response to EGFR-targeted inhibitors.

The Significance of Ras Activity in Pancreatic Cancer Initiation.

PubMed

Logsdon, Craig D; Lu, Weiqin

2016-01-01

The genetic landscape of pancreatic cancer shows nearly ubiquitous mutations of K-RAS. However, oncogenic K-Ras(mt) alone is not sufficient to lead to pancreatic ductal adenocarcinoma (PDAC) in either human or in genetically modified adult mouse models. Many stimulants, such as high fat diet, CCK, LPS, PGE2 and others, have physiological effects at low concentrations that are mediated in part through modest increases in K-Ras activity. However, at high concentrations, they induce inflammation that, in the presence of oncogenic K-Ras expression, substantially accelerates PDAC formation. The mechanism involves increased activity of oncogenic K-Ras(mt). Unlike what has been proposed in the standard paradigm for the role of Ras in oncogenesis, oncogenic K-Ras(mt) is now known to not be constitutively active. Rather, it can be activated by standard mechanisms similar to wild-type K-Ras, but its activity is sustained for a prolonged period. Furthermore, if the level of K-Ras activity exceeds a threshold at which it begins to generate its own activators, then a feed-forward loop is formed between K-Ras activity and inflammation and pathological processes including oncogenesis are initiated. Oncogenic K-Ras(mt) activation, a key event in PDAC initiation and development, is subject to complex regulatory mechanisms. Reagents which inhibit inflammation, such as the Cox2 inhibitor celecoxib, block the feed-forward loop and prevent induction of PDAC in models with endogenous oncogenic K-Ras(mt). Increased understanding of the role of activating and inhibitory mechanisms on oncogenic K-Ras(mt) activity is of paramount importance for the development of preventive and therapeutic strategies to fight against this lethal disease.