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Sample records for overexpressed wild-type kras

  1. Wild-type KRAS inhibits oncogenic KRAS-induced T-ALL in mice.

    PubMed

    Staffas, A; Karlsson, C; Persson, M; Palmqvist, L; Bergo, M O

    2015-05-01

    The role of hyperactive RAS signaling is well established in myeloid malignancies but less clear in T-cell malignancies. The Kras2(LSL)Mx1-Cre (KM) mouse model expresses endogenous KRAS(G12D) in hematopoietic cells and is widely used to study mechanisms and treatment of myeloproliferative neoplasms (MPN). The model displays an intriguing shift from MPN to acute T-cell leukemia (T-ALL) after transplantation to wild-type mice, but the mechanisms underlying this lineage shift is unknown. Here, we show that KRAS(G12D) increases proliferation of both myeloid and T-cell progenitors, but whereas myeloid cells differentiate, T-cell differentiation is inhibited at early stages. Secondary mutations in the expanded pool of T-cell progenitors accompany T-ALL development, and our results indicate that the shift from myeloid to T-lymphoid malignancy after transplantation is explained by the increased likelihood for secondary mutations when the tumor lifespan is increased. We demonstrate that tumor lifespan increases after transplantation because primary KM mice die rapidly, not from MPN, but from KRAS(G12D) expression in nonhematopoietic cells, which causes intestinal bleeding and severe anemia. We also identify loss of the wild-type KRAS allele as a secondary mutation in all T-ALL cells and provide evidence that wild-type KRAS acts as a tumor suppressor in the T-cell lineage in mice. PMID:25371176

  2. The Differential Effects of Wild-Type and Mutated K-Ras on MST2 Signaling Are Determined by K-Ras Activation Kinetics

    PubMed Central

    Romano, David; Maccario, Helene; Doherty, Carolanne; Quinn, Niall P.

    2013-01-01

    K-Ras is frequently mutated in human cancers. Mutant (mt) K-Ras can stimulate both oncogenic transformation and apoptosis through activation of extracellular signal-regulated kinase (ERK) and AKT pathways and the MST2 pathway, respectively. The biological outcome is determined by the balance and cross talk between these pathways. In colorectal cancer (CRC), a K-Ras mutation is negatively correlated with MST2 expression, as mt K-Ras can induce apoptosis by activating the MST2 pathway. However, wild-type (wt) K-Ras can prevent the activation of the MST2 pathway upon growth factor stimulation and enable transformation by mt K-Ras in CRC cells that express MST2. Here we have investigated the mechanism by which wt and mt K-Ras differentially regulate the MST2 pathway and MST2-dependent apoptosis. The ability of K-Ras to activate MST2 and MST2-dependent apoptosis is determined by the differential activation kinetics of mt K-Ras and wt K-Ras. Chronic activation of K-Ras by mutation or overexpression of Ras exchange factors results in the activation of MST2 and LATS1, increased MST2-LATS1 complex formation, and apoptosis. In contrast, transient K-Ras activation upon epidermal growth factor (EGF) stimulation prevents the formation of the MST2-LATS1 complex in an AKT-dependent manner. Our data suggest that the close relationship between Ras prosurvival and proapoptotic signaling is coordinated via the differential regulation of the MST2-LATS1 interaction by transient and chronic stimuli. PMID:23459937

  3. Biomarkers predicting resistance to epidermal growth factor receptor-targeted therapy in metastatic colorectal cancer with wild-type KRAS

    PubMed Central

    Liu, Jiang; Hu, Jing; Cheng, Lei; Ren, Wei; Yang, Mi; Liu, Baorui; Xie, Li; Qian, Xiaoping

    2016-01-01

    EGFR pathway is an important therapeutic target in human tumors, including metastatic colorectal cancer (mCRC). The advent of EGFR-targeted monoclonal antibodies panitumumab and cetuximab has generated promise for the treatment of mCRC and has largely improved patients’ progression-free survival (PFS) and overall survival (OS). However, treatment with anti-EGFR monoclonal antibodies is only effective in a subset of mCRC patients with wild-type KRAS. This indicates that there are other factors affecting the efficacy of anti-EGFR monoclonal antibodies. Existing studies have demonstrated that among colorectal cancer patients with wild-type KRAS, harboring mutations of BRAF, PIK3CA, NRAS, or PTEN-null may demonstrate resistance to anti-EGFR-targeted therapy, and biomarkers detection can provide better-personalized treatment for mCRC patients. How to identify and reverse the secondary resistance to anti-EGFR monoclonal antibody therapy is also another great challenge to improve the anti-EGFR efficacy in wild-type KRAS mCRC patients. Finally, both of the molecular mechanisms of response and acquired resistance would be important for the directions of future research. This review focuses on how to further improve the predictive value of anti-EGFR therapies and how to also try and avoid futile treatment for wild-type KRAS colorectal cancer patients. PMID:26869800

  4. Germ cell tumors of the testis overexpress wild-type p53.

    PubMed Central

    Guillou, L.; Estreicher, A.; Chaubert, P.; Hurlimann, J.; Kurt, A. M.; Metthez, G.; Iggo, R.; Gray, A. C.; Jichlinski, P.; Leisinger, H. J.; Benhattar, J.

    1996-01-01

    Several recent studies have suggested that testicular germ cell tumors express high levels of wild-type p53 protein. To clarify and confirm this unexpected result, we have investigated seminomatous and nonseminomatous germ cell tumors at the genomic, mRNA, and protein levels. Thirty-five tumors were examined for p53 overexpression using antibodies directed against the p53 (PAb1801, PAb240, and CM1), mdm2 (IF2), and p21Waf1/Clp1 (EA10) proteins. Thirty-two tumors were screened for p53 mutations by single-strand conformation polymorphism analysis. Eighteen tumors were screened with a functional assay that tests the transcriptional competence of human p53 protein expressed in yeast. On frozen sections, 100, 65, 35, 73, and 0% of tumors reacted with the CM1, PAb240, PAb1801, IF2, and EA10 antibodies, respectively. No p53 mutations were detected by single-strand conformation polymorphism or by functional assay. The fact that many tumors overexpress wild-type p53 but not mdm2 rules out mdm2 overexpression as a general explanation for the presence of wild-type p53 in these tumors. The absence of p21 overexpression suggests that p53 may be unable to activate transcription of critical target genes, which may explain why the presence of wild-type p53 is tolerated in this tumor type, although the mechanism for this transcriptional inactivity remains to be established. Images Figure 1 Figure 2 PMID:8863671

  5. First-line cetuximab-based chemotherapies for patients with advanced or metastatic KRAS wild-type colorectal cancer

    PubMed Central

    Uemura, Mamoru; Kim, Ho Min; Hata, Tsuyoshi; Sakata, Kazuya; Okuyama, Masaki; Takemoto, Hiroyoshi; Fujii, Hitoshi; Fukuzaki, Takayuki; Morita, Tetsushi; Hata, Taishi; Takemasa, Ichiro; Satoh, Taroh; Mizushima, Tsunekazu; Doki, Yuichiro; Mori, Maski

    2016-01-01

    Colorectal cancer (CRC) is one of the most commonly occurring cancers worldwide. A burgeoning number of studies have demonstrated that the addition of cetuximab to another standard first-line regimen markedly improves the outcome of CRC treatment. However, at present, the efficacy and safety of cetuximab-based combination chemotherapy has not been well described in Japan. The aim of the present study was to evaluate the efficacy and safety of first-line chemotherapies that included cetuximab for patients with advanced or metastatic Kirsten rat sarcoma viral oncogene homolog (KRAS) wild-type CRC in Japan. This prospective multicenter observational study was conducted at 13 affiliated medical institutions. A total of 64 patients were enrolled between 2010 and 2013. The patients met the following criteria for eligibility: i) histologically confirmed, advanced or metastatic KRAS wild-type CRC; and ii) cetuximab-based chemotherapies administered as a first-line treatment. First-line cetuximab-based treatments were administered as follows: 29 patients (45.3%) received a combination of infusional fluorouracil, leucovorin and oxaliplatin; 14 patients (21.9%) received a combination of capecitabine and oxaliplatin; and 10 patients (15.6%) received a combination of infusional fluorouracil, leucovorin and irinotecan. The overall response rate (including complete plus partial responses) was 50% (32/64 patients). Initially, 48 lesions were diagnosed as unresectable. Among those, 13 lesions (27.1%) were converted to a resectable status following cetuximab-based combination chemotherapy treatments. The median overall survival time and the progression-free survival time were 1,189 and 359 days, respectively. The most frequent grade 3/4 adverse event was neutropenia, which occurred in 20.3% of the patients. The incidence of grade 3/4 skin toxicity was 17.2% (11/64 patients). Cetuximab-based therapies may represent a promising first-line regimen for patients with advanced or

  6. Combination of cetuximab and PP242 synergistically suppress the progression of wild-type KRAS colorectal carcinoma

    PubMed Central

    Cheng, Lei; Xia, Zuguang; Bian, Xinyu; Li, Guangchao; Hu, Jing; Cao, Ya; Wang, Qing; Qian, Xiaoping

    2015-01-01

    Mammalian target of rapamycin (mTOR) has been shown to be overactive in human colorectal cancer, but the first-generation mTOR inhibitor, rapamycin, has failed to show clinical efficacy against colorectal cancer. On the other hand, although the second-generation mTOR inhibitor, PP242, has exerted substantial efficacy, it was revealed that independent inhibition by PP242 was transient, which could lead to positive-feedback loop to EGFR. Using wild-type KRAS colorectal cancer cells as models, we investigate the treatment efficacy of a widely used anti-EGFR monoclonal antibody, cetuximab, and PP242, alone or in combination in vitro and in vivo. Results of cell viability assays confirmed the synergistic inhibitory effect of PP242 and cetuximab on the survival of Caco-2 and HT-29 cells. Moreover, the ability of cancer-cell invasion and proliferation was also significantly inhibited by the combination therapy when compared with cetuximab or PP242 alone. Interestingly, the percentage of CD44-positive cancer cells was substantially decreased by the combination therapy in comparison with PP242 alone through fluorescence-activated cell sorting. The growth of cancer stem-like cell spheres in vitro was also maximally inhibited by combination therapy, in terms of either diameter or number. More importantly, the efficacy of combination therapy was more prominent than either drug alone in established tumor xenografts. These findings supported the potential use of combination therapy of PP242 and cetuximab against wild-type KRAS colorectal carcinomas. PMID:26586952

  7. Overexpression of Wild-Type Murine Tau Results in Progressive Tauopathy and Neurodegeneration

    PubMed Central

    Adams, Stephanie J.; Crook, Richard J.P.; DeTure, Michael; Randle, Suzanne J.; Innes, Amy E.; Yu, Xin Z.; Lin, Wen-Lang; Dugger, Brittany N.; McBride, Melinda; Hutton, Mike; Dickson, Dennis W.; McGowan, Eileen

    2009-01-01

    Here, we describe the generation and characterization of a novel tau transgenic mouse model (mTau) that overexpresses wild-type murine tau protein by twofold compared with endogenous levels. Transgenic tau expression was driven by a BAC transgene containing the entire wild-type mouse tau locus, including the endogenous promoter and the regulatory elements associated with the tau gene. The mTau model therefore differs from other tau models in that regulation of the genomic mouse transgene mimics that of the endogenous gene, including normal exon splicing regulation. Biochemical data from the mTau mice demonstrated that modest elevation of mouse tau leads to tau hyperphosphorylation at multiple pathologically relevant epitopes and accumulation of sarkosyl-insoluble tau. The mTau mice show a progressive increase in hyperphosphorylated tau pathology with age up to 15 to 18 months, which is accompanied by gliosis and vacuolization. In contrast, older mice show a decrease in tau pathology levels, which may represent hippocampal neuronal loss occurring in this wild-type model. Collectively, these results describe a novel model of tauopathy that develops pathological changes reminiscent of early stage Alzheimer’s disease and other related neurodegenerative diseases, achieved without overexpression of a mutant human tau transgene. This model will provide an important tool for understanding the early events leading to the development of tau pathology and a model for analysis of potential therapeutic targets for sporadic tauopathies. PMID:19717642

  8. Adenocarcinoma arising from intracranial recurrent mature teratoma and featuring mutated KRAS and wild-type BRAF genes.

    PubMed

    Kim, Eun Soo; Kwon, Mi Jung; Song, Joon Ho; Kim, Dong Hoon; Park, Hye-Rim

    2015-02-01

    Malignant transformation or recurrence of intracranial mature teratoma is an extremely rare occurrence, compared to the usual ovarian counterpart. Previously, yolk sac tumor elements have been considered to be selective progenitors of enteric-type adenocarcinoma arising from intracranial germ cell tumors. However, the present case demonstrates the occurrence of enteric-type adenocarcinoma in recurrent intracranial mature cystic teratoma 12 years after gross total removal, a case of which has not previously been documented in the literature. The 11.5-cm long, dura mater-based tumor on the right fronto-temporal lobe displaced the brain; however, the patient had no neurologic symptoms or discomfort other than pus-like discharge on the scalp. Microscopic examinations revealed a small focus of adenocarcinoma and dysplastic colonic mucosa in the mature cystic teratoma. No immature elements were seen. The cystic wall was almost denuded and showed an exuberant xanthogranulomatous reaction with foreign-body type giant cells engulfing keratin materials and cholesterol clefts, suggesting that chronic inflammation due to repeated cyst wall rupture and the previous resection may contribute to malignant transformation. The adenocarcinoma showed strong immunohistochemical expression of CK20 and p53, but CK7 in patches. The molecular profile of the adenocarcinoma showed a mutation in KRAS and wild-type BRAF, which might be associated with malignant transformation of intracranial mature teratomas. In conclusion, the intracranial mature teratomas should require long-term follow-up, and clinicians, radiologists and pathologists should be aware of the potential for malignant progression of recurrent intracranial mature cystic teratoma despite gross total resection and no neurologic symptoms. PMID:25039399

  9. Induction of breast cancer in wild type p53 cells by BRCA1-IRIS overexpression.

    PubMed

    Elshamy, Wael M

    2010-08-01

    Cells ability to evade cell death and to proliferate post geno-/cell-toxic stresses, likely leads to formation of cancer. Activation of p38MAPK and p53 following these stresses help protect cells against cancer development by initiating apoptosis. The duration of p38MAPK and p53 activation is regulated by the WIP1 phosphatase. BRCA1-IRIS triggers WIP1 expression in p53-dependent and -independent manner. BRCA1-IRIS triggers the expression and cytoplasmic localization of the mRNA stabilization and translation inducer, HuR that binds p53 and PPM1D mRNA. Hence, BRCA1-IRIS overexpression inactivates p38MAPK and/or p53 by upregulating WIP1 expression. BRCA1-IRIS abrogation of the homeostatic balance maintained by p38MAPK-p53-WIP1 pathway suppressed cell death induced by a lethal dose of UVC, high dosages of etoposide or H2O2, and allowed cells to survive and proliferate post geno-/cell-toxic stresses. This mechanism represents a new link between geno-/cell-toxic stress and aggressive breast cancer formation in p53 wild-type cells. PMID:20845286

  10. Germline polymorphisms in genes involved in the IGF1-pathway predict efficacy of cetuximab in wild-type KRAS mCRC patients

    PubMed Central

    Winder, Thomas; Zhang, Wu; Yang, Dongyun; Ning, Yan; Bohanes, Pierre; Gerger, Armin; Wilson, Peter M.; Pohl, Alexandra; Mauro, David J.; Langer, Christiane; Rowinsky, Eric K.; Lenz, Heinz-Josef

    2010-01-01

    Purpose The insulin-like growth factor 1 (IGF1) signalling pathway is an important growth-regulatory pathway, which plays a crucial role in colorectal cancer (CRC) proliferation, differentiation, migration, angiogenesis, and apoptosis. Previous studies showed that hyperactivation of the IGF1-Receptor (IGF1R) may result in resistance to anti-EGFR targeted treatment. We tested whether germline variations within the IGF1-pathway are associated with clinical outcome in wild-type KRAS (wt KRAS) drug-refractory metastatic CRC (mCRC) patients who were treated with cetuximab monotherapy (IMC-0144). Experimental Design Formalin-fixed paraffin-embedded (FFPE) tissue samples of 130 drug-refractory mCRC patients enrolled in IMC-0144, a phase II clinical trial of cetuximab monotherapy, were analyzed. gDNA was extracted from dissected FFPE tumor tissue and KRAS mutation status and six potentially functional IGF1 and IGF1R polymorphisms were analyzed using direct DNA-sequencing or PCR-RFLP. Tumor response analysis was based on recursive partitioning and survival analyses were based on univariate and multivariate hazard regression models. Results In univariate and multivariate analyses five IGF-pathway SNPs were significantly associated with progression-free-survival (PFS) and/or overall survival (OS). In multivariate combined risk allele analysis the additive model for PFS and OS was significantly associated with the number of risk alleles in wt KRAS patients (p=0.001 and p=0.02, respectively). In addition, wt KRAS patients harbouring IGF1 rs2946834 A/A genotype had a 50 % ORR compared to 0% for A/G genotype. Conclusions These results indicate that IGF1-pathway polymorphisms are potential predictive/prognostic molecular markers for cetuximab efficacy in wt KRAS mCRC patients. Prospective biomarker embedded clinical trials are warranted to validate our findings. PMID:20935157

  11. Single-Tubed Wild-Type Blocking Quantitative PCR Detection Assay for the Sensitive Detection of Codon 12 and 13 KRAS Mutations

    PubMed Central

    Duan, Guang-Jie; Shi, Yan; Deng, Guo-Hong; Xia, Han; Xu, Han-Qing; Zhao, Na; Fu, Wei-Ling; Huang, Qing

    2015-01-01

    The high degree of intra-tumor heterogeneity has meant that it is important to develop sensitive and selective assays to detect low-abundance KRAS mutations in metastatic colorectal carcinoma (mCRC) patients. As a major potential source of tumor DNA in the aforementioned genotyping assays, it was necessary to conduct an analysis on both the quality and quantity of DNA extracted from formalin-fixed paraffin-embedded (FFPE). Therefore, four commercial FFPE DNA extraction kits were initially compared with respect to their ability to facilitate extraction of amplifiable DNA. The results showed that TrimGen kits showed the greatest performance in relation to the quality and quantity of extracted FFPE DNA solutions. Using DNA extracted by TrimGen kits as a template for tumor genotyping, a real-time wild-type blocking PCR (WTB-PCR) assay was subsequently developed to detect the aforementioned KRAS mutations in mCRC patients. The results showed that WTB-PCR facilitated the detection of mutated alleles at a ratio of 1:10,000 (i.e. 0.01%) wild-type alleles. When the assay was subsequently used to test 49 mCRC patients, the results showed that the mutation detection levels of the WTB-PCR assay (61.8%; 30/49) were significantly higher than that of traditional PCR (38.8%; 19/49). Following the use of the real-time WTB-PCR assay, the ΔCq method was used to quantitatively analyze the mutation levels associated with KRAS in each FFPE sample. The results showed that the mutant levels ranged from 53.74 to 0.12% in the patients analyzed. In conclusion, the current real-time WTB-PCR is a rapid, simple, and low-cost method that permits the detection of trace amounts of the mutated KRAS gene. PMID:26701781

  12. Amplification-free In Situ KRAS Point Mutation Detection at 60 copies/mL in Urine in a Background of 1000-fold Wild Type

    PubMed Central

    KirimLi, Ceyhun E.; Shih, Wei-Heng; Shih, Wan Y.

    2016-01-01

    We have examined in situ detection of single-nucleotide KRAS mutation in urine using a (Pb(Mg1/3Nb2/3)O3)0.65(PbTiO3)0.35 (PMN-PT) piezoelectric plate sensor (PEPS) coated with a 17-nucleotide (nt) locked nucleic acid (LNA) probe DNA complementary to the KRAS mutation. To enhance in situ mutant (MT) DNA detection specificity against the wild type (WT), the detection was carried out in a flow with a flow rate of 4 mL/min and at 63°C with the PEPS vertically situated at the center of the flow in which both the temperature and the flow impingement force discriminated the wild type. Under such conditions, PEPS was shown to specifically detect KRAS MT in situ with 60 copies/mL analytical sensitivity in a background of clinically-relevant 1000-fold more WT in 30 min without DNA isolation, amplification, or labeling. For validation, the detection was followed with detection in a mixture of blue MT fluorescent reporter microspheres (FRMs) (MT FRMs) that bound to only the captured MT and orange WT FRMs that bound to only the captured WT. Microscopic examinations showed that the captured blue MT FRMs still outnumbered the orange WT FRMs by a factor of 4 to 1 even though WT was 1000-fold of MT in urine. Finally, multiplexed specific mutation detection was demonstrated using a 6-PEPS array each with a probe DNA targeting one of the 6 codon-12 KRAS mutations. PMID:26783561

  13. Amplification-free in situ KRAS point mutation detection at 60 copies per mL in urine in a background of 1000-fold wild type.

    PubMed

    Kirimli, Ceyhun E; Shih, Wei-Heng; Shih, Wan Y

    2016-02-21

    We have examined the in situ detection of a single-nucleotide KRAS mutation in urine using a (Pb(Mg1/3Nb2/3)O3)0.65(PbTiO3)0.35 (PMN-PT) piezoelectric plate sensor (PEPS) coated with a 17-nucleotide (nt) locked nucleic acid (LNA) probe DNA complementary to the KRAS mutation. To enhance the in situ mutant (MT) DNA detection specificity against the wild type (WT), detection was carried out in a flow with a flow rate of 4 mL min(-1) and at 63 °C with the PEPS vertically situated at the center of the flow in which both the temperature and the flow impingement force discriminated the wild type. Under such conditions, PEPS was shown to specifically detect KRAS MT in situ with 60 copies per mL analytical sensitivity in a background of clinically-relevant 1000-fold more WT in 30 min without DNA isolation, amplification, or labeling. For validation, this detection was followed with detection in a mixture of blue MT fluorescent reporter microspheres (FRMs) (MT FRMs) that bound to only the captured MT and orange WT FRMs that bound to only the captured WT. Microscopic examinations showed that the captured blue MT FRMs still outnumbered the orange WT FRMs by a factor of 4 to 1 even though WT was 1000-fold of MT in urine. Finally, multiplexed specific mutation detection was demonstrated using a 6-PEPS array each with a probe DNA targeting one of the 6 codon-12 KRAS mutations. PMID:26783561

  14. Differential proteomic and behavioral effects of long-term voluntary exercise in wild-type and APP-overexpressing transgenics.

    PubMed

    Rao, Shailaja Kishan; Ross, Jordan M; Harrison, Fiona E; Bernardo, Alexandra; Reiserer, Randall S; Reiserer, Ronald S; Mobley, James A; McDonald, Michael P

    2015-06-01

    Physical exercise may provide protection against the cognitive decline and neuropathology associated with Alzheimer's disease, although the mechanisms are not clear. In the present study, APP/PSEN1 double-transgenic and wild-type mice were allowed unlimited voluntary exercise for 7months. Consistent with previous reports, wheel-running improved cognition in the double-transgenic mice. Interestingly, the average daily distance run was strongly correlated with spatial memory in the water maze in wild-type mice (r(2)=.959), but uncorrelated in transgenics (r(2)=.013). Proteomics analysis showed that sedentary transgenic mice differed significantly from sedentary wild-types with respect to proteins involved in synaptic transmission, cytoskeletal regulation, and neurogenesis. When given an opportunity to exercise, the transgenics' deficiencies in cytoskeletal regulation and neurogenesis largely normalized, but abnormal synaptic proteins did not change. In contrast, exercise enhanced proteins associated with cytoskeletal regulation, oxidative phosphorylation, and synaptic transmission in wild-type mice. Soluble and insoluble Aβ40 and Aβ42 levels were significantly decreased in both cortex and hippocampus of active transgenics, suggesting that this may have played a role in the cognitive improvement in APP/PSEN1 mice. β-secretase was significantly reduced in active APP/PSEN1 mice compared to sedentary controls, suggesting a mechanism for reduced Aβ. Taken together, these data illustrate that exercise improves memory in wild-type and APP-overexpressing mice in fundamentally different ways. PMID:25818006

  15. Podocyte-Specific Overexpression of Wild Type or Mutant Trpc6 in Mice Is Sufficient to Cause Glomerular Disease

    PubMed Central

    Kairath, Pamela; Carmona-Mora, Paulina; Molina, Jessica; Carpio, J. Daniel; Ruiz, Phillip; Mezzano, Sergio A.; Li, Jing; Wei, Changli; Reiser, Jochen; Young, Juan I.; Walz, Katherina

    2010-01-01

    Mutations in the TRPC6 calcium channel (Transient receptor potential channel 6) gene have been associated with familiar forms of Focal and Segmental Glomerulosclerosis (FSGS) affecting children and adults. In addition, acquired glomerular diseases are associated with increased expression levels of TRPC6. However, the exact role of TRPC6 in the pathogenesis of FSGS remains to be elucidated. In this work we describe the generation and phenotypic characterization of three different transgenic mouse lines with podocyte-specific overexpression of the wild type or any of two mutant forms of Trpc6 (P111Q and E896K) previously related to FSGS. Consistent with the human phenotype a non-nephrotic range of albuminuria was detectable in almost all transgenic lines. The histological analysis demonstrated that the transgenic mice developed a kidney disease similar to human FSGS. Differences of 2–3 folds in the presence of glomerular lesions were found between the non transgenic and transgenic mice expressing Trpc6 in its wild type or mutant forms specifically in podocytes. Electron microscopy of glomerulus from transgenic mice showed extensive podocyte foot process effacement. We conclude that overexpression of Trpc6 (wild type or mutated) in podocytes is sufficient to cause a kidney disease consistent with FSGS. Our results contribute to reinforce the central role of podocytes in the etiology of FSGS. These mice constitute an important new model in which to study future therapies and outcomes of this complex disease. PMID:20877463

  16. A CDK4/6 inhibitor enhances cytotoxicity of paclitaxel in lung adenocarcinoma cells harboring mutant KRAS as well as wild-type KRAS.

    PubMed

    Zhang, Xiang-Hua; Cheng, Ying; Shin, Jung-Young; Kim, Jeong-Oh; Oh, Ji-Eun; Kang, Jin-Hyoung

    2013-07-01

    The KRAS gain-of-function mutation confers intrinsic resistance to targeted anti-cancer drugs and cytotoxic chemotherapeutic agents, ultimately leading to treatment failure. KRAS mutation frequency in lung adenocarcinoma is ~15-30%. Novel therapeutic strategies should be developed to improve clinical outcomes in these cases. Deregulation of the p16/cyclin-dependent kinase (CDK) 4/retinoblastoma (Rb) pathway is frequently observed in various cancers and it represents an attractive therapeutic target. We compared the anti-tumor efficacy of genetically knocked-down CDK4 and a pharmacological inhibitor of CDK4/6, CINK4, in KRAS mutation-positive lung adenocarcinoma cells. We also investigated changes in anti-proliferative activity and downstream molecules with these treatments in combination with paclitaxel. CDK4 short interfering RNA (siRNA) significantly increased paclitaxel sensitivity in KRAS mutation-positive H23 cells. CINK4 demonstrated concentration- and time-dependent anti-proliferative activity in 5 adenocarcinoma lines. CINK4 induced G 1 arrest by downregulating the p16/cyclin D1/Rb pathway, resulting in apoptotic induction via increased expression of cleaved caspase3, cleaved PARP and Bax. Combined CINK4 and paclitaxel produced synergistic anti-proliferative activity and increased apoptosis through reduced cyclin D1 and Bcl-2 in KRAS mutation-positive cancer cells. These data suggest CDK4 is a promising target for development of anti-cancer drugs and CINK4 combined with paclitaxel may be an effective therapeutic strategy for enhancing anti-tumor efficacy in KRAS mutation-positive lung adenocarcinoma. PMID:23792647

  17. Clinical outcome of panitumumab for metastatic colorectal cancer with wild-type KRAS status: a meta-analysis of randomized clinical trials.

    PubMed

    Ibrahim, Ezzeldin M; Abouelkhair, Khaled M

    2011-12-01

    Panitumumab is a fully human anti-epidermal growth factor receptor (EGFR) monoclonal antibody that has a favorable effect on patients with metastatic colorectal cancer (mCRC) harboring wild-type (WT) KRAS gene. This meta-analysis was planned to quantify the benefit and assess safety. Selected for the analysis were randomized clinical studies that have used panitumumab-based therapy (PBT) for patients with mCRC and where the outcome of patients with WT KRAS was reported. Four eligible studies were analyzed including 1,010 and 1,105 patients who received PBT and the control intervention, respectively. Used in subsequent-line setting, PBT was associated with 42% improvement in progression-free survival (PFS) (hazard ratio [HR] = 0.58; 95% CI, 0.36-0.93; P = 0.02), a non-significant overall survival (OS) benefit (HR = 0.90; [95% CI, 0.76-1.05]; P = 0.18), and a significant increase in objective response rate (ORR) (odds ratio (OR) = 0.67 [95% CI, 1.15-77.98]; P = 0.04). PBT showed no benefit in the first-line setting. Restricted analysis to two studies (first- and second-line setting), where the treatment effect of PBT was prospectively analyzed according to tumor KRAS status, showed significant PFS (HR = 0.77), OS (HR = 0.84), and ORR (OR = 2.06) advantage. Almost all patients' subgroups attained clinical benefit. PBT-related adverse events were similar across comparisons with the exception of toxicities known to be associated with anti-EGFR therapy. This meta-analysis showed significant clinical benefit for PBT for patients with WT KRAS mCRC predominantly when used following prior chemotherapy exposure. The benefit was demonstrated in most subgroup analyses. Further research to better define potential responders is needed. PMID:21221853

  18. Profile of panitumumab as first-line treatment in patients with wild-type KRAS metastatic colorectal cancer.

    PubMed

    Patel, Shiven B; Gill, David; Garrido-Laguna, Ignacio

    2016-01-01

    Targeted therapies against EGFR, vascular endothelial growth factor, and vascular endothelial growth factor receptor have expanded treatment options for patients with metastatic colorectal cancer (mCRC). Unfortunately, biomarkers to identify patients that are most likely to derive benefit from targeted therapies in this disease are still needed. Indeed, only RAS mutations have been identified as predictive of lack of benefit from monoclonal antibodies against EGFR in patients with mCRC. Panitumumab is a fully humanized monoclonal antibody against EGFR. In this study, we review data to support the use of panitumumab in combination with a chemotherapy backbone, in the first line setting in patients with RAS wild-type mCRC. Ongoing efforts are aimed at identifying smaller subsets of patients within the RAS wild-type group that will derive the largest benefit from anti-EGFR therapy. In the meantime, treatment with anti-EGFR therapy should be reserved for patients with RAS wild-type mCRC. PMID:26770060

  19. Profile of panitumumab as first-line treatment in patients with wild-type KRAS metastatic colorectal cancer

    PubMed Central

    Patel, Shiven B; Gill, David; Garrido-Laguna, Ignacio

    2016-01-01

    Targeted therapies against EGFR, vascular endothelial growth factor, and vascular endothelial growth factor receptor have expanded treatment options for patients with metastatic colorectal cancer (mCRC). Unfortunately, biomarkers to identify patients that are most likely to derive benefit from targeted therapies in this disease are still needed. Indeed, only RAS mutations have been identified as predictive of lack of benefit from monoclonal antibodies against EGFR in patients with mCRC. Panitumumab is a fully humanized monoclonal antibody against EGFR. In this study, we review data to support the use of panitumumab in combination with a chemotherapy backbone, in the first line setting in patients with RAS wild-type mCRC. Ongoing efforts are aimed at identifying smaller subsets of patients within the RAS wild-type group that will derive the largest benefit from anti-EGFR therapy. In the meantime, treatment with anti-EGFR therapy should be reserved for patients with RAS wild-type mCRC. PMID:26770060

  20. Comparative metabolomics profiling of isogenic KRAS wild type and mutant NSCLC cells in vitro and in vivo

    PubMed Central

    Brunelli, Laura; Caiola, Elisa; Marabese, Mirko; Broggini, Massimo; Pastorelli, Roberta

    2016-01-01

    Oncogenes induce metabolic reprogramming on cancer cells. Recently, G12C KRAS mutation in isogenic NSCLC cell line has been shown to be a key player in promoting metabolic rewiring mainly through the regulation of glutamine metabolism to fuel growth and proliferation. Even though cell lines possessing many of the genetic backgrounds of the primary cancer they derive from could be a valuable pre-clinical model, they do not have the additional complexity present in the whole tumor that impact metabolism. This preliminary study is aimed to explore how cancer cell metabolism in culture might recapitulate the metabolic alterations present in vivo. Our result highlighted that the gross metabolic changes observed in G12C KRAS mutant cells growing in culture were also maintained in the derived xenograft model, suggesting that a simple in vitro cell model can give important insights into the metabolic alterations induced by cancer. This is of relevance for guiding effective targeting of those metabolic traits that underlie tumor progression and anticancer treatment responses. PMID:27329432

  1. Comparative metabolomics profiling of isogenic KRAS wild type and mutant NSCLC cells in vitro and in vivo.

    PubMed

    Brunelli, Laura; Caiola, Elisa; Marabese, Mirko; Broggini, Massimo; Pastorelli, Roberta

    2016-01-01

    Oncogenes induce metabolic reprogramming on cancer cells. Recently, G12C KRAS mutation in isogenic NSCLC cell line has been shown to be a key player in promoting metabolic rewiring mainly through the regulation of glutamine metabolism to fuel growth and proliferation. Even though cell lines possessing many of the genetic backgrounds of the primary cancer they derive from could be a valuable pre-clinical model, they do not have the additional complexity present in the whole tumor that impact metabolism. This preliminary study is aimed to explore how cancer cell metabolism in culture might recapitulate the metabolic alterations present in vivo. Our result highlighted that the gross metabolic changes observed in G12C KRAS mutant cells growing in culture were also maintained in the derived xenograft model, suggesting that a simple in vitro cell model can give important insights into the metabolic alterations induced by cancer. This is of relevance for guiding effective targeting of those metabolic traits that underlie tumor progression and anticancer treatment responses. PMID:27329432

  2. Accelerated telomere shortening and replicative senescence in human fibroblasts overexpressing mutant and wild-type lamin A

    SciTech Connect

    Huang Shurong; Risques, Rosa Ana; Martin, George M.; Rabinovitch, Peter S.; Oshima, Junko

    2008-01-01

    LMNA mutations are responsible for a variety of genetic disorders, including muscular dystrophy, lipodystrophy, and certain progeroid syndromes, notably Hutchinson-Gilford Progeria. Although a number of clinical features of these disorders are suggestive of accelerated aging, it is not known whether cells derived from these patients exhibit cellular phenotypes associated with accelerated aging. We examined a series of isogenic skin fibroblast lines transfected with LMNA constructs bearing known pathogenic point mutations or deletion mutations found in progeroid syndromes. Fibroblasts overexpressing mutant lamin A exhibited accelerated rates of loss of telomeres and shortened replicative lifespans, in addition to abnormal nuclear morphology. To our surprise, these abnormalities were also observed in lines overexpressing wild-type lamin A. Copy number variants are common in human populations; those involving LMNA, whether arising meiotically or mitotically, might lead to progeroid phenotypes. In an initial pilot study of 23 progeroid cases without detectable WRN or LMNA mutations, however, no cases of altered LMNA copy number were detected. Nevertheless, our findings raise a hypothesis that changes in lamina organization may cause accelerated telomere attrition, with different kinetics for overexpession of wild-type and mutant lamin A, which leads to rapid replicative senescence and progroid phenotypes.

  3. Overexpression of wild-type or mutants forms of CEBPA alter normal human hematopoiesis.

    PubMed

    Quintana-Bustamante, O; Lan-Lan Smith, S; Griessinger, E; Reyal, Y; Vargaftig, J; Lister, T A; Fitzgibbon, J; Bonnet, D

    2012-07-01

    CCAAT/enhancer-binding protein-α (C/EBPα/CEBPA) is mutated in approximately 8% of acute myeloid leukemia (AML) in both familial and sporadic AML and, with FLT3 and NPM1, has received most attention as a predictive marker of outcome in patients with normal karyotype disease. Mutations clustering to either the N- or C-terminal (N- and C-ter) portions of the protein have different consequences on the protein function. In familial cases, the N-ter form is inherited with patients exhibiting long latency period before the onset of overt disease, typically with the acquisition of a C-ter mutation. Despite the essential insights murine models provide the functional consequences of wild-type C/EBPα in human hematopoiesis and how different mutations are involved in AML development have received less attention. Our data underline the critical role of C/EBPα in human hematopoiesis and demonstrate that C/EBPα mutations (alone or in combination) are insufficient to convert normal human hematopoietic stem/progenitor cells into leukemic-initiating cells, although individually each altered normal hematopoiesis. It provides the first insight into the effects of N- and C-ter mutations acting alone and to the combined effects of N/C double mutants. Our results mimicked closely what happens in CEBPA mutated patients. PMID:22371011

  4. Genomic markers of panitumumab resistance including ERBB2/HER2 in a phase II study of KRAS wild-type (wt) metastatic colorectal cancer (mCRC)

    PubMed Central

    Barry, Garrett S.; Cheang, Maggie C.; Chang, Hector Li; Kennecke, Hagen F.

    2016-01-01

    A prospective study was conducted to identify biomarkers associated with resistance to panitumumab monotherapy in patients with metastatic colorectal cancer (mCRC). Patients with previously treated, codon 12/13 KRAS wt, mCRC were prospectively administered panitumumab 6 mg/kg IV q2weeks. Of 34 panitumumab-treated patients, 11 (32%) had progressive disease at 8 weeks and were classified as non-responders. A Nanostring nCounter-based assay identified a 5-gene expression signature (ERBB2, MLPH, IRX3, MYRF, and KLK6) associated with panitumumab resistance (P = 0.001). Immunohistochemistry and in situ hybridization determined that the HER2 (ERBB2) protein was overexpressed in 4/11 non-responding and 0/21 responding cases (P = 0.035). Two non-responding tumors had ERBB2 gene amplification only, and one demonstrated both ERBB2 amplification and mutation. A non-codon 12/13 KRAS mutation occurred in one panitumumab-resistant patient and was mutually exclusive with ERBB2/HER2 abnormalities. This study identifies a 5-gene signature associated with non-response to single agent panitumumab, including a subgroup of non-responders with evidence of aberrant ERBB2/HER2 signaling. KRAS wt tumors resistant to EGFRi may be identified by gene signature analysis, and the HER2 pathway plays an important role in resistance to therapy. PMID:26980732

  5. Wild-type SOD1 overexpression accelerates disease onset of a G85R SOD1 mouse

    PubMed Central

    Wang, Lijun; Deng, Han-Xiang; Grisotti, Gabriella; Zhai, Hong; Siddique, Teepu; Roos, Raymond P.

    2009-01-01

    Approximately 10% of amyotrophic lateral sclerosis (ALS) cases are familial (FALS), and ∼25% of FALS cases are caused by mutations in Cu/Zn superoxide dismutase type 1 (SOD1). Mutant (MT) SOD1 is thought to be pathogenic because it misfolds and aggregates. A number of transgenic mice have been generated that express different MTSOD1s as transgenes and exhibit an ALS-like disease. Although one study found that overexpression of human wild-type (WT) SOD1 did not affect disease in G85R transgenic mice, more recent reports claim that overexpression of WTSOD1 in other MTSOD1 transgenic mice hastened disease, raising a possibility that the effect of WTSOD1 overexpression in this FALS mouse model is mutant-specific. In order to clarify this issue, we studied the effect of WTSOD1 overexpression in a G85R transgenic mouse that we recently generated. We found that G85R/WTSOD1 double transgenic mice had an acceleration of disease onset and shortened survival compared with G85R single transgenic mice; in addition, there was an earlier appearance of pathological and immunohistochemical abnormalities. The spinal cord insoluble fraction from G85R/WTSOD1 mice had evidence of G85R–WTSOD1 heterodimers and WTSOD1 homodimers (in addition to G85R homodimers) with intermolecular disulfide bond cross-linking. These studies suggest that WTSOD1 can be recruited into disease-associated aggregates by redox processes, providing an explanation for the accelerated disease seen in G85R mice following WTSOD1 overexpression, and suggesting the importance of incorrect disulfide-linked protein as key to MTSOD1 toxicity. PMID:19233858

  6. Mitochondrial defects and neurodegeneration in mice overexpressing wild-type or G399S mutant HtrA2.

    PubMed

    Casadei, Nicolas; Sood, Poonam; Ulrich, Thomas; Fallier-Becker, Petra; Kieper, Nicole; Helling, Stefan; May, Caroline; Glaab, Enrico; Chen, Jing; Nuber, Silke; Marcus, Katrin; Rapaport, Doron; Ott, Thomas; Riess, Olaf; Krüger, Rejko; Fitzgerald, Julia C

    2016-02-01

    The protease HtrA2 has a protective role inside mitochondria, but promotes apoptosis under stress. We previously identified the G399S HtrA2 mutation in Parkinson's disease (PD) patients and reported mitochondrial dysfunction in vitro. Mitochondrial dysfunction is a common feature of PD and related to neurodegeneration. Complete loss of HtrA2 has been shown to cause neurodegeneration in mice. However, the full impact of HtrA2 overexpression or the G399S mutation is still to be determined in vivo. Here, we report the first HtrA2 G399S transgenic mouse model. Our data suggest that the mutation has a dominant-negative effect. We also describe a toxic effect of wild-type (WT) HtrA2 overexpression. Only low overexpression of the G399S mutation allowed viable animals and we suggest that the mutant protein is likely unstable. This is accompanied by reduced mitochondrial respiratory capacity and sensitivity to apoptotic cell death. Mice overexpressing WT HtrA2 were viable, yet these animals have inhibited mitochondrial respiration and significant induction of apoptosis in the brain leading to motor dysfunction, highlighting the opposing roles of HtrA2. Our data further underscore the importance of HtrA2 as a key mediator of mitochondrial function and its fine regulatory role in cell fate. The location and abundance of HtrA2 is tightly controlled and, therefore, human mutations leading to gain- or loss of function could provide significant risk for PD-related neurodegeneration. PMID:26604148

  7. Prolonged ethanol administration depletes mitochondrial DNA in MnSOD-overexpressing transgenic mice, but not in their wild type littermates

    SciTech Connect

    Larosche, Isabelle; Choumar, Amal; Fromenty, Bernard; Letteron, Philippe; Abbey-Toby, Adje; Van Remmen, Holly; Epstein, Charles J.; Richardson, Arlan; Feldmann, Gerard; Pessayre, Dominique; Mansouri, Abdellah

    2009-02-01

    Alcohol consumption increases reactive oxygen species formation and lipid peroxidation, whose products can damage mitochondrial DNA (mtDNA) and alter mitochondrial function. A possible role of manganese superoxide dismutase (MnSOD) on these effects has not been investigated. To test whether MnSOD overexpression modulates alcohol-induced mitochondrial alterations, we added ethanol to the drinking water of transgenic MnSOD-overexpressing (TgMnSOD) mice and their wild type (WT) littermates for 7 weeks. In TgMnSOD mice, alcohol administration further increased the activity of MnSOD, but decreased cytosolic glutathione as well as cytosolic glutathione peroxidase activity and peroxisomal catalase activity. Whereas ethanol increased cytochrome P-450 2E1 and mitochondrial ROS generation in both WT and TgMnSOD mice, hepatic iron, lipid peroxidation products and respiratory complex I protein carbonyls were only increased in ethanol-treated TgMnSOD mice but not in WT mice. In ethanol-fed TgMnSOD mice, but not ethanol-fed WT mice, mtDNA was depleted, and mtDNA lesions blocked the progress of polymerases. The iron chelator, DFO prevented hepatic iron accumulation, lipid peroxidation, protein carbonyl formation and mtDNA depletion in alcohol-treated TgMnSOD mice. Alcohol markedly decreased the activities of complexes I, IV and V of the respiratory chain in TgMnSOD, with absent or lesser effects in WT mice. There was no inflammation, apoptosis or necrosis, and steatosis was similar in ethanol-treated WT and TgMnSOD mice. In conclusion, prolonged alcohol administration selectively triggers iron accumulation, lipid peroxidation, respiratory complex I protein carbonylation, mtDNA lesions blocking the progress of polymerases, mtDNA depletion and respiratory complex dysfunction in TgMnSOD mice but not in WT mice.

  8. Which is false: oxaliplatin or fluoropyrimidine? An analysis of patients with KRAS wild-type metastatic colorectal cancer treated with first-line epidermal growth factor receptor monoclonal antibody.

    PubMed

    Wen, Feng; Tang, Ruilei; Sang, Yaxiong; Li, Meng; Hu, Qiancheng; Du, Zedong; Zhou, Yi; Zhang, Pengfei; He, Xiaofeng; Li, Qiu

    2013-10-01

    This meta-analysis was performed to determine whether the addition of monoclonal antibodies (mAbs) of epidermal growth factor receptor (EGFR) to oxaliplatin-based chemotherapy treatment improves efficacy in KRAS wild-type metastatic colorectal cancer (mCRC), and whether infusional 5-fluorouracil (5-FU) and oxaliplatin is a preferred combination for EGFR mAbs. Oxaliplatin (including treatment), EGFR mAbs, first-line treatment, KRAS wild-type, and mCRC were used as key words. The PRIME, OPUS, COIN, and NORDIC VII trials were identified by two independent authors. Time-to-event outcomes of overall survival (OS) and progression-free survival (PFS) were analyzed using HRs (hazard ratios) with fixed effect, and response rate (RR) using odd ratios (OR) with fixed effect. A total of 1767 patients who were KRAS wild-type were included in this meta-analysis, with 866 patients in the mAbs and chemotherapy combination group and 901 patients in the chemotherapy alone group. The addition of mAbs to oxaliplatin-based chemotherapy in patients with KRAS wild-type mCRC as first-line treatment resulted in significant improvements in PFS (HR = 0.88; 95% confidence interval (CI), 0.79-0.99; P = 0.03) and response rate (RR) (OR = 1.38; 95% CI, 1.14-1.66; P = 0.009) compared with chemotherapy alone, but the difference in OS was not significant (HR = 0.96; 95% CI, 0.85-1.08; P = 0.48). However, the differences in OS and PFS were not significant when mAbs were added to bolus 5-FU or capecitabine-based regimens compared with chemotherapy alone, whereas PFS improved with an infusional 5-FU and oxaliplatin combination (P = 0.06; PFS, HR = 0.76; 95% CI, 0.65-0.86; P = 0.0002), and even OS was marginally significant, which was consistent with the subgroup analysis of cetuximab and panitumumab. EGFR mAbs combined with oxaliplatin and an infusional 5-FU regimen was associated with significantly improved RR, PFS and OS as first-line treatment in KRAS wild-type mCRC. PMID:23822592

  9. Perturbation of Auxin Homeostasis by Overexpression of Wild-Type IAA15 Results in Impaired Stem Cell Differentiation and Gravitropism in Roots

    PubMed Central

    Yan, Da-Wei; Wang, Jing; Yuan, Ting-Ting; Hong, Li-Wei; Gao, Xiang; Lu, Ying-Tang

    2013-01-01

    Aux/IAAs interact with auxin response factors (ARFs) to repress their transcriptional activity in the auxin signaling pathway. Previous studies have focused on gain-of-function mutations of domain II and little is known about whether the expression level of wild-type Aux/IAAs can modulate auxin homeostasis. Here we examined the perturbation of auxin homeostasis by ectopic expression of wild-type IAA15. Root gravitropism and stem cell differentiation were also analyzed. The transgenic lines were less sensitive to exogenous auxin and exhibited low-auxin phenotypes including failures in gravity response and defects in stem cell differentiation. Overexpression lines also showed an increase in auxin concentration and reduced polar auxin transport. These results demonstrate that an alteration in the expression of wild-type IAA15 can disrupt auxin homeostasis. PMID:23472140

  10. Overexpression of ALS-associated p.M337V human TDP-43 in mice worsens disease features compared to wild-type human TDP-43 mice.

    PubMed

    Janssens, Jonathan; Wils, Hans; Kleinberger, Gernot; Joris, Geert; Cuijt, Ivy; Ceuterick-de Groote, Chantal; Van Broeckhoven, Christine; Kumar-Singh, Samir

    2013-08-01

    Mutations in TAR DNA-binding protein 43 (TDP-43) are associated with familial forms of amyotrophic lateral sclerosis (ALS), while wild-type TDP-43 is a pathological hallmark of patients with sporadic ALS and frontotemporal lobar degeneration (FTLD). Various in vitro and in vivo studies have also demonstrated toxicity of both mutant and wild-type TDP-43 to neuronal cells. To study the potential additional toxicity incurred by mutant TDP-43 in vivo, we generated mutant human TDP-43 (p.M337V) transgenic mouse lines driven by the Thy-1.2 promoter (Mt-TAR) and compared them in the same experimental setting to the disease phenotype observed in wild-type TDP-43 transgenic lines (Wt-TAR) expressing comparable TDP-43 levels. Overexpression of mutant TDP-43 leads to a worsened dose-dependent disease phenotype in terms of motor dysfunction, neurodegeneration, gliosis, and development of ubiquitin and phosphorylated TDP-43 pathology. Furthermore, we show that cellular aggregate formation or accumulation of TDP-43 C-terminal fragments (CTFs) are not primarily responsible for development of the observed disease phenotype in both mutant and wild-type TDP-43 mice. PMID:23475610

  11. MiR-200c overexpression is associated with better efficacy of EGFR-TKIs in non-small cell lung cancer patients with EGFR wild-type

    PubMed Central

    Li, Jiayu; Li, Xuefei; Ren, Shengxiang; Chen, Xiaoxia; Zhang, Yishi; Zhou, Fei; Zhao, Mingchuan; Zhao, Chao; Chen, Xiu; Cheng, Ningning; Zhao, Yinmin; Zhou, Caicun; Hirsch, Fred R.

    2014-01-01

    Several randomized trials have demonstrated non-small cell lung cancer (NSCLC) patients with activating epidermal growth factor receptor (EGFR) mutations can achieve favorable clinical outcomes on treatment with EGFR tyrosine kinase inhibitors (TKIs). EGFR mutation is considered as a predictive marker for efficacy of EGFR-TKIs in NSCLC. Here we show miR-200c overexpression was correlated with the epithelial phenotype and sensitivity to gefitinib in EGFR wild-type NSCLC cell lines. Up-regulated miR-200c could regain the sensitivity to gefitinib in the EGFR wild-type cell lines and miR-200c could regulate epithelial to mesenchymal transition through PI3K/AKT and MEK/ERK pathways. NSCLC patients at advanced stage (N=150) who received EGFR-TKIs (gefitinib or erlotinib) as second- or third-line therapy from September 2008 to December 2012 were included in the study. In 66 NSCLC patients with wild-type EGFR, high levels of miR-200c expression was associated with higher disease control rate (DCR), longer progression-free survival (PFS) and longer overall survival (OS) compared with low miR-200c expression subgroup. In the subgroup with EGFR mutation, the trend remained the same but not statistically significant. Overall, these findings indicated that miR-200c might be a predictive biomarker for sensitivity to EGFR-TKIs in advanced NSCLC patients with wild-type EGFR. PMID:25277203

  12. Mobility and subcellular localization of endogenous, gene-edited Tau differs from that of over-expressed human wild-type and P301L mutant Tau

    PubMed Central

    Di Xia; Gutmann, Julia M.; Götz, Jürgen

    2016-01-01

    Alzheimer’s disease (AD) and a subset of frontotemporal dementia termed FTLD-Tau are characterized by a massive, yet incompletely characterized and understood redistribution of Tau. To establish a framework for understanding this pathology, we used the genome-editing tool TALEN and generated Tau-mEOS2 knock-in mice to determine the mobility and subcellular localization of endogenous Tau in hippocampal cultures. We analysed Tau in axons, dendrites and spines at three stages of maturation using live-cell imaging, photo-conversion and FRAP assays. Tau-mEOS2 cultures were compared with those over-expressing EGFP-tagged forms of human wild-type (hWT-Tau) and P301L mutant Tau (hP301L-Tau), modelling Tau accumulation in AD and FTLD-Tau, respectively. In developing neurons, Tau-mEOS2 followed a proximo-distal gradient in axons and a subcellular distribution similar to that of endogenous Tau in neurons obtained from wild-type mice, which were abolished, when either hWT-Tau or hP301L-Tau was over-expressed. For the three conditions, FRAP analysis revealed a similar mobility in dendrites compared with axons; however, Tau-mEOS2 was less mobile than hWT-Tau and hP301L-Tau and the mobile fraction was smaller, possibly reflecting less efficient microtubule binding of Tau when over-expressed. Together, our study presents Tau-mEOS2 mice as a novel tool for the study of Tau in a physiological and a pathological context. PMID:27378256

  13. Mobility and subcellular localization of endogenous, gene-edited Tau differs from that of over-expressed human wild-type and P301L mutant Tau.

    PubMed

    Di Xia; Gutmann, Julia M; Götz, Jürgen

    2016-01-01

    Alzheimer's disease (AD) and a subset of frontotemporal dementia termed FTLD-Tau are characterized by a massive, yet incompletely characterized and understood redistribution of Tau. To establish a framework for understanding this pathology, we used the genome-editing tool TALEN and generated Tau-mEOS2 knock-in mice to determine the mobility and subcellular localization of endogenous Tau in hippocampal cultures. We analysed Tau in axons, dendrites and spines at three stages of maturation using live-cell imaging, photo-conversion and FRAP assays. Tau-mEOS2 cultures were compared with those over-expressing EGFP-tagged forms of human wild-type (hWT-Tau) and P301L mutant Tau (hP301L-Tau), modelling Tau accumulation in AD and FTLD-Tau, respectively. In developing neurons, Tau-mEOS2 followed a proximo-distal gradient in axons and a subcellular distribution similar to that of endogenous Tau in neurons obtained from wild-type mice, which were abolished, when either hWT-Tau or hP301L-Tau was over-expressed. For the three conditions, FRAP analysis revealed a similar mobility in dendrites compared with axons; however, Tau-mEOS2 was less mobile than hWT-Tau and hP301L-Tau and the mobile fraction was smaller, possibly reflecting less efficient microtubule binding of Tau when over-expressed. Together, our study presents Tau-mEOS2 mice as a novel tool for the study of Tau in a physiological and a pathological context. PMID:27378256

  14. Analysis of striatal transcriptome in mice overexpressing human wild-type alpha-synuclein supports synaptic dysfunction and suggests mechanisms of neuroprotection for striatal neurons

    PubMed Central

    2011-01-01

    Background Alpha synuclein (SNCA) has been linked to neurodegenerative diseases (synucleinopathies) that include Parkinson's disease (PD). Although the primary neurodegeneration in PD involves nigrostriatal dopaminergic neurons, more extensive yet regionally selective neurodegeneration is observed in other synucleinopathies. Furthermore, SNCA is ubiquitously expressed in neurons and numerous neuronal systems are dysfunctional in PD. Therefore it is of interest to understand how overexpression of SNCA affects neuronal function in regions not directly targeted for neurodegeneration in PD. Results The present study investigated the consequences of SNCA overexpression on cellular processes and functions in the striatum of mice overexpressing wild-type, human SNCA under the Thy1 promoter (Thy1-aSyn mice) by transcriptome analysis. The analysis revealed alterations in multiple biological processes in the striatum of Thy1-aSyn mice, including synaptic plasticity, signaling, transcription, apoptosis, and neurogenesis. Conclusion The results support a key role for SNCA in synaptic function and revealed an apoptotic signature in Thy1-aSyn mice, which together with specific alterations of neuroprotective genes suggest the activation of adaptive compensatory mechanisms that may protect striatal neurons in conditions of neuronal overexpression of SNCA. PMID:22165993

  15. Lead uptake increases drought tolerance of wild type and transgenic poplar (Populus tremula x P. alba) overexpressing gsh 1.

    PubMed

    Samuilov, Sladjana; Lang, Friedericke; Djukic, Matilda; Djunisijevic-Bojovic, Danijela; Rennenberg, Heinz

    2016-09-01

    Growth and development of plants largely depends on their adaptation ability in a changing climate. This is particularly true on heavy metal contaminated soils, but the interaction of heavy metal stress and climate on plant performance has not been intensively investigated. The aim of the present study was to elucidate if transgenic poplars (Populus tremula x P. alba) with enhanced glutathione content possess an enhanced tolerance to drought and lead (Pb) exposure (single and in combination) and if they are good candidates for phytoremediation of Pb contaminated soil. Lead exposure reduced growth and biomass accumulation only in above-ground tissue of wild type poplar, although most of lead accumulated in the roots. Drought caused a decline of the water content rather than reduced biomass production, while Pb counteracted this decline in the combined exposure. Apparently, metals such as Pb possess a protective function against drought, because they interact with abscisic acid dependent stomatal closure. Lead exposure decreased while drought increased glutathione content in leaves of both plant types. Lead accumulation was higher in the roots of transgenic plants, presumably as a result of chelation by glutathione. Water deprivation enhanced Pb accumulation in the roots, but Pb was subject to leakage out of the roots after re-watering. Transgenic plants showed better adaptation under mild drought plus Pb exposure partially due to improved glutathione synthesis. However, the transgenic plants cannot be considered as a good candidate for phytoremediation of Pb, due to its small translocation to the shoots and its leakage out of the roots upon re-watering. PMID:27396669

  16. Overexpression of Galgt2 in skeletal muscle prevents injury resulting from eccentric contractions in both mdx and wild-type mice.

    PubMed

    Martin, Paul T; Xu, Rui; Rodino-Klapac, Louise R; Oglesbay, Elaine; Camboni, Marybeth; Montgomery, Chrystal L; Shontz, Kim; Chicoine, Louis G; Clark, K Reed; Sahenk, Zarife; Mendell, Jerry R; Janssen, Paul M L

    2009-03-01

    The cytotoxic T cell (CT) GalNAc transferase, or Galgt2, is a UDP-GalNAc:beta1,4-N-acetylgalactosaminyltransferase that is localized to the neuromuscular synapse in adult skeletal muscle, where it creates the synaptic CT carbohydrate antigen {GalNAcbeta1,4[NeuAc(orGc)alpha2, 3]Galbeta1,4GlcNAcbeta-}. Overexpression of Galgt2 in the skeletal muscles of transgenic mice inhibits the development of muscular dystrophy in mdx mice, a model for Duchenne muscular dystrophy. Here, we provide physiological evidence as to how Galgt2 may inhibit the development of muscle pathology in mdx animals. Both Galgt2 transgenic wild-type and mdx skeletal muscles showed a marked improvement in normalized isometric force during repetitive eccentric contractions relative to nontransgenic littermates, even using a paradigm where nontransgenic muscles had force reductions of 95% or more. Muscles from Galgt2 transgenic mice, however, showed a significant decrement in normalized specific force and in hindlimb and forelimb grip strength at some ages. Overexpression of Galgt2 in muscles of young adult mdx mice, where Galgt2 has no effect on muscle size, also caused a significant decrease in force drop during eccentric contractions and increased normalized specific force. A comparison of Galgt2 and microdystrophin overexpression using a therapeutically relevant intravascular gene delivery protocol showed Galgt2 was as effective as microdystrophin at preventing loss of force during eccentric contractions. These experiments provide a mechanism to explain why Galgt2 overexpression inhibits muscular dystrophy in mdx muscles. That overexpression also prevents loss of force in nondystrophic muscles suggests that Galgt2 is a therapeutic target with broad potential applications. PMID:19109526

  17. A randomized, placebo-controlled, phase 1/2 study of tivantinib (ARQ 197) in combination with irinotecan and cetuximab in patients with metastatic colorectal cancer with wild-type KRAS who have received first-line systemic therapy.

    PubMed

    Eng, Cathy; Bessudo, Alberto; Hart, Lowell L; Severtsev, Aleksey; Gladkov, Oleg; Müller, Lothar; Kopp, Mikhail V; Vladimirov, Vladimir; Langdon, Robert; Kotiv, Bogdan; Barni, Sandro; Hsu, Ching; Bolotin, Ellen; von Roemeling, Reinhard; Schwartz, Brian; Bendell, Johanna C

    2016-07-01

    Cetuximab in combination with an irinotecan-containing regimen is a standard treatment in patients with KRAS wild-type (KRAS WT), metastatic colorectal cancer (mCRC). We investigated the addition of the oral MET inhibitor tivantinib to cetuximab + irinotecan (CETIRI) based on preclinical evidence that activation of the MET pathway may confer resistance to anti-EGFR therapy. Previously treated patients with KRAS WT advanced or mCRC were enrolled. The phase 1, open-label 3 + 3, dose-escalation study evaluated the safety and maximally tolerated dose of tivantinib plus CETIRI. The phase 2, randomized, double-blinded, placebo-controlled study of biweekly CETIRI plus tivantinib or placebo was restricted to patients who had received only one prior line of chemotherapy. The phase 2 primary endpoint was progression-free survival (PFS). The recommended phase 2 dose was tivantinib (360 mg/m(2) twice daily) with biweekly cetuximab (500 mg/m(2)) and irinotecan (180 mg/m(2)). Among 117 patients evaluable for phase 2 analysis, no statistically significant PFS difference was observed: 8.3 months on tivantinib vs. 7.3 months on placebo (HR, 0.85; 95% confidence interval, 0.55-1.33; P = 0.38). Subgroup analyses trended in favor of tivantinib in patients with MET-High tumors by immunohistochemistry, PTEN-Low tumors, or those pretreated with oxaliplatin, but subgroups were too small to draw conclusions. Neutropenia, diarrhea, nausea and rash were the most frequent severe adverse events in tivantinib-treated patients. The combination of tivantinib and CETIRI was well tolerated but did not significantly improve PFS in previously treated KRAS WT mCRC. Tivantinib may be more active in specific subgroups. PMID:26891420

  18. G48A, a New KRAS Mutation Found in Lung Adenocarcinoma.

    PubMed

    Marabese, Mirko; Caiola, Elisa; Garassino, Marina C; Rastelli, Giulio; Settanni, Giulio; Brugnara, Sonia; Broggini, Massimo; Ganzinelli, Monica

    2016-07-01

    A new somatic mutation in the coding region of Kirsten rat sarcoma viral oncogene homolog gene (KRAS), G48A, has been identified in a patient with non-small cell lung cancer (NSCLC). No other mutations were found by screening several genes known to be mutated in NSCLC. The patient responded to first-line therapy and is still under maintenance treatment 18 months after diagnosis. Normal and cancer cells were engineered to express the KRAS(G48A) mutation. KRAS(G48A) overexpression did not change the growth or the response to treatment compared with KRAS(wild type)-expressing cells. Analysis of the structure of the KRAS(G48A) mutant predicted altered interactions with other proteins. Analysis of KRAS binding to B-Raf proto-oncogene, serine/threonine kinase showed that the KRAS(G48A) mutant behaves more like a wild-type than a classical KRAS(G12) mutant. In conclusion, this new mutation in the coding region of KRAS, found in NSCLC, does not induce phenotypic changes similar to those induced by G12 mutants but presumably affects KRAS binding to proteins other than B-Raf proto-oncogene, serine/threonine kinase. PMID:27058911

  19. Higher metastatic efficiency of KRas G12V than KRas G13D in a colorectal cancer model.

    PubMed

    Alamo, Patricia; Gallardo, Alberto; Di Nicolantonio, Federica; Pavón, Miguel Angel; Casanova, Isolda; Trias, Manuel; Mangues, María Antonia; Lopez-Pousa, Antonio; Villaverde, Antonio; Vázquez, Esther; Bardelli, Alberto; Céspedes, María Virtudes; Mangues, Ramón

    2015-02-01

    Although all KRas (protein that in humans is encoded by the KRas gene) point mutants are considered to have a similar prognostic capacity, their transformation and tumorigenic capacities vary widely. We compared the metastatic efficiency of KRas G12V (Kirsten rat sarcoma viral oncogene homolog with valine mutation at codon 12) and KRas G13D (Kirsten rat sarcoma viral oncogene homolog with aspartic mutation at codon 13) oncogenes in an orthotopic colorectal cancer (CRC) model. Following subcutaneous preconditioning, recombinant clones of the SW48 CRC cell line [Kras wild-type (Kras WT)] expressing the KRas G12V or KRas G13D allele were microinjected in the mouse cecum. The percentage of animals developing lymph node metastasis was higher in KRas G12V than in KRas G13D mice. Microscopic, macroscopic, and visible lymphatic foci were 1.5- to 3.0-fold larger in KRas G12V than in KRas G13D mice (P < 0.05). In the lung, only microfoci were developed in both groups. KRas G12V primary tumors had lower apoptosis (7.0 ± 1.2 vs. 7.4 ± 1.0 per field, P = 0.02), higher tumor budding at the invasion front (1.2 ± 0.2 vs. 0.6 ± 0.1, P = 0.04), and a higher percentage of C-X-C chemokine receptor type 4 (CXCR4)-overexpressing intravasated tumor emboli (49.8 ± 9.4% vs. 12.8 ± 4.4%, P < 0.001) than KRas G13D tumors. KRas G12V primary tumors showed Akt activation, and β5 integrin, vascular endothelial growth factor A (VEGFA), and Serpine-1 overexpression, whereas KRas G13D tumors showed integrin β1 and angiopoietin 2 (Angpt2) overexpression. The increased cell survival, invasion, intravasation, and specific molecular regulation observed in KRas G12V tumors is consistent with the higher aggressiveness observed in patients with CRC expressing this oncogene. PMID:25359494

  20. Capturing the metabolomic diversity of KRAS mutants in non-small-cell lung cancer cells

    PubMed Central

    Marabese, Mirko; Broggini, Massimo; Pastorelli, Roberta

    2014-01-01

    In non-small-cell lung cancer (NSCLC), one-fifth of patients have KRAS mutations, which are considered a negative predictive factor to first-line therapy. Evidence is emerging that not all KRAS mutations have the same biological activities and possible remodeling of cell metabolism by KRAS activation might complicate the scenario. An open question is whether different KRAS mutations at codon-12 affect cellular metabolism differently with possible implications for different responses to cancer treatments. We applied an explorative mass spectrometry-based untargeted metabolomics strategy to characterize the largest possible number of metabolites that might distinguish isogenic NSCLC cells overexpressing mutated forms of KRAS at codon-12 (G12C, G12D, G12V) and the wild-type. The glutamine deprivation assay and real-time PCR were used to confirm the involvement of some of the metabolic pathways highlighted. Cell clones indicated distinct metabolomic profiles in KRAS wild-type and mutants. Clones harboring different KRAS mutations at codon-12 also had different metabolic remodeling, such as a different redox buffering system and different glutamine-dependency not driven by the transcriptional state of enzymes involved in glutaminolysis. These findings indicate that KRAS mutations at codon-12 are associated with different metabolomic profiles that might affect the responses to cancer treatments. PMID:24952473

  1. Suppression of KRas-mutant cancer through the combined inhibition of KRAS with PLK1 and ROCK

    PubMed Central

    Wang, Jieqiong; Hu, Kewen; Guo, Jiawei; Cheng, Feixiong; Lv, Jing; Jiang, Wenhao; Lu, Weiqiang; Liu, Jinsong; Pang, Xiufeng; Liu, Mingyao

    2016-01-01

    No effective targeted therapies exist for cancers with somatic KRAS mutations. Here we develop a synthetic lethal chemical screen in isogenic KRAS-mutant and wild-type cells to identify clinical drug pairs. Our results show that dual inhibition of polo-like kinase 1 and RhoA/Rho kinase (ROCK) leads to the synergistic effects in KRAS-mutant cancers. Microarray analysis reveals that this combinatory inhibition significantly increases transcription and activity of cyclin-dependent kinase inhibitor p21WAF1/CIP1, leading to specific G2/M phase blockade in KRAS-mutant cells. Overexpression of p21WAF1/CIP1, either by cDNA transfection or clinical drugs, preferentially impairs the growth of KRAS-mutant cells, suggesting a druggable synthetic lethal interaction between KRAS and p21WAF1/CIP1. Co-administration of BI-2536 and fasudil either in the LSL-KRASG12D mouse model or in a patient tumour explant mouse model of KRAS-mutant lung cancer suppresses tumour growth and significantly prolongs mouse survival, suggesting a strong synergy in vivo and a potential avenue for therapeutic treatment of KRAS-mutant cancers. PMID:27193833

  2. Lin28-let7 Modulates Radiosensitivity of Human Cancer Cells With Activation of K-Ras

    SciTech Connect

    Oh, Jee-Sun.; Kim, Jae-Jin; Byun, Ju-Yeon; Kim, In-Ah

    2010-01-15

    Purpose: To evaluate the potential of targeting Lin28-let7 microRNA regulatory network for overcoming the radioresistance of cancer cells having activated K-Ras signaling. Methods and Materials: A549 lung carcinoma cells and ASPC1 pancreatic cancer cells possessing K-RAS mutation were transfected with pre-let7a microRNA or Lin28 siRNA, respectively. Clonogenic assay, quantitative reverse transcription polymerase chain reaction, and Western analysis were performed. The effects of Lin28 on SQ20B cells having wild-type K-RAS, and a normal fibroblast were also assessed. Results: The overexpression of let-7a decreased expression of K-Ras and radiosensitized A549 cells. Inhibition of Lin28, a repressor of let-7, attenuated K-Ras expression and radiosensitized A549 and ASPC1 cells. Neither SQ20B cells expressing wild-type K-RAS nor HDF, the normal human fibroblasts, were radiosensitized by this approach. Conclusions: The Lin28-let7 regulatory network may be a potentially useful therapeutic target for overcoming the radioresistance of human cancers having activated K-Ras signaling.

  3. Mutant KRAS Conversion of Conventional T Cells into Regulatory T Cells.

    PubMed

    Zdanov, Stephanie; Mandapathil, Magis; Abu Eid, Rasha; Adamson-Fadeyi, Saudat; Wilson, Willie; Qian, Jiahua; Carnie, Andrea; Tarasova, Nadya; Mkrtichyan, Mikayel; Berzofsky, Jay A; Whiteside, Theresa L; Khleif, Samir N

    2016-04-01

    Constitutive activation of theKRASoncogene in human malignancies is associated with aggressive tumor growth and poor prognosis. Similar to other oncogenes,KRASacts in a cell-intrinsic manner to affect tumor growth or survival. However, we describe here a different, cell-extrinsic mechanism through which mutant KRAS contributes to tumor development. Tumor cells carrying mutated KRAS induced highly suppressive T cells, and silencing KRAS reversed this effect. Overexpression of the mutantKRAS(G12V)gene in wild-type KRAS tumor cells led to regulatory T-cell (Treg) induction. We also demonstrate that mutant KRAS induces the secretion of IL10 and transforming growth factor-β1 (both required for Treg induction) by tumor cells through the activation of the MEK-ERK-AP1 pathway. Finally, we report that inhibition of KRAS reduces the infiltration of Tregs in KRAS-driven lung tumorigenesis even before tumor formation. This cell-extrinsic mechanism allows tumor cells harboring a mutantKRASoncogene to escape immune recognition. Thus, an oncogene can promote tumor progression independent of its transforming activity by increasing the number and function of Tregs. This has a significant clinical potential, in which targeting KRAS and its downstream signaling pathways could be used as powerful immune modulators in cancer immunotherapy.Cancer Immunol Res; 4(4); 354-65. ©2016 AACR. PMID:26880715

  4. ERK2-dependent reactivation of Akt mediates the limited response of tumor cells with constitutive K-RAS activity to PI3K inhibition

    PubMed Central

    Toulany, Mahmoud; Minjgee, Minjmaa; Saki, Mohammad; Holler, Marina; Meier, Friedegund; Eicheler, Wolfgang; Rodemann, H Peter

    2014-01-01

    K-RAS mutated (K-RASmut) non-small cell lung cancer (NSCLC) cells are resistant to EGFR targeting strategies. We investigated the impact of K-RAS activity irrespective of mutational status in the EGFR-independent increase in clonogenic cell survival. An analysis of the K-RAS activity status revealed a constitutively high K-RAS activity in K-RASmut NSCLC cells and also in head and neck squamous cell carcinoma (HNSCC) cells overexpressing wild-type K-RAS (K-RASwt). Similar to K-RAS-mutated cells, increased K-RAS activity in HNSCC cells overexpressing K-RASwt was associated with the stimulated production of the EGFR ligand amphiregulin and resistance to EGFR tyrosine kinase (EGFR-TK) inhibitors such as erlotinib. Expression of mutated K-RAS stimulated Akt phosphorylation and increased plating efficiency. Conversely, knockdown of K-RAS in K-RASmut NSCLC cells and in HNSCC cells presenting overexpression of K-RASwt resulted in sensitization to the anti-clonogenic activity of erlotinib. K-RAS activity results in EGFR-dependent and EGFR-independent Akt activity. The short-term treatment (2 h) of cells with EGFR-TK or PI3K inhibitors (erlotinib and PI-103) resulted in the repression of Akt activation, whereas long-term treatment (24 h) with inhibitors led to the reactivation of Akt and improved clonogenicity. The Akt re-activation was MAPK-ERK2-dependent and associated with a lack of complete response to anti-clonogenic activity of PI-103. A complete response was observed when PI-103 was combined with MEK inhibitor PD98059. Together, clonogenicity inhibition in tumor cells presenting constitutive K-RAS activity independent of K-RAS mutational status can be achieved by targeting of EGFR downstream pathways, i.e., PI3K alone or the combination of PI3K and MAPK inhibitors. PMID:24351425

  5. "Wild type" GIST: Clinicopathological features and clinical practice.

    PubMed

    Wada, Ryuichi; Arai, Hiroki; Kure, Shoko; Peng, Wei-Xia; Naito, Zenya

    2016-08-01

    Gastrointestinal stromal tumor (GIST) is a mesenchymal tumor of the gastrointestinal tract. Mutation of KIT and PDGFRA genes is implicated in the tumorigenesis. Approximately 10% of GISTs do not harbor mutation of these genes, and they are designated as "wild type" GIST. They are classified into succinate dehydrogenase (SDH)-deficient and non-SDH-deficient groups. SDH-deficient group includes Carney triad and Carney Stratakis syndrome. The patients are young women. Tumors occur in the antrum of the stomach, and tumor cells are epithelioid. Lymph node metastasis is frequent. The non-SDH-deficient group includes neurofibromatosis (NF) type 1 and GISTs with mutations of BRAF, KRAS, and PIK3CA and with the ETV6-NTRK3 fusion gene. GIST in NF occurs in the small intestine, and tumor cells are spindle shaped. GIST with BRAF mutation arises in the small intestine. Attention to the age, gender, family history and other neoplasms may raise the prediction of syndromic disease. Location of the tumor, morphology, and pleomorphism of the tumor cells are further informative. Lymphovascular invasion should be carefully evaluated. The determination of KIT expression is essential for the diagnosis. When wild type GIST is suspected, intensive genetic analysis is required. Further, a careful and long-time observation is recommended. PMID:27427238

  6. Radiohybridization PET imaging of KRAS G12D mRNA expression in human pancreas cancer xenografts with [(64)Cu]DO3A-peptide nucleic acid-peptide nanoparticles.

    PubMed

    Chakrabarti, A; Zhang, K; Aruva, M R; Cardi, C A; Opitz, A W; Wagner, N J; Thakur, M L; Wickstrom, E

    2007-06-01

    There is a compelling need to image pancreas cancer at an early stage. Human pancreas cancer cells display elevated levels of KRAS protein due to high copy numbers of KRAS mRNA, and elevated levels of insulin-like growth factor 1 receptor (IGF1R) due to overexpression of IGF1R mRNA. Therefore we hypothesized that pancreas cancer could be detected in vivo with a single probe that targets both KRAS mRNA and IGF1R. Because positron emission tomography (PET) is a sensitive imaging technique, we designed a probe incorporating the positron-emitting nuclide (64)Cu. The KRAS-specific hybridization probe consisted of 1,4,7-tris(carboxymethylaza)cyclododecane-10-aza-acetyl (DO3A) on the N-terminus of a peptide nucleic acid (PNA) hybridization sequence (GCCATCAGCTCC) linked to a cyclized IGF1 peptide analog (d-Cys-Ser-Lys-Cys) on the C-terminus, for IGF1R-mediated endocytosis. A series of such KRAS radiohybridization probes with 0, 1, 2 or 3 mismatches to KRAS G12D mRNA, including exact matches to wild type KRAS mRNA and KRAS G12V mRNA, along with a double d(Ala) replacement IGF1 peptide control, were assembled by continuous solid phase synthesis. To test the hypothesis that KRAS-IGF1 dual probes could specifically image KRAS mRNA expression noninvasively in human IGF1R-overexpressing AsPC1 pancreas cancer xenografts in immunocompromised mice, [(64)Cu]PNA radiohybridization probes and controls were administered by tail vein. The [(64)Cu]KRAS-IGF1 radiohybridization probe yielded strong tumor contrast in PET images, 8.6 +/- 1.4-fold more intense in the center of human pancreas cancer xenografts than in the contralateral muscle at 4 h post-injection. Control experiments with single base KRASmismatches, an IGF1 peptide mismatch, and a breast cancer xenograft lacking KRAS activation yielded weak tumor contrast images. These experiments are consistent with our hypothesis for noninvasive PET imaging of KRAS oncogene expression in pancreas cancer xenografts. Imaging oncogene m

  7. KRAS Mutation

    PubMed Central

    Franklin, Wilbur A.; Haney, Jerry; Sugita, Michio; Bemis, Lynne; Jimeno, Antonio; Messersmith, Wells A.

    2010-01-01

    Treatment of colon carcinoma with the anti-epidermal growth factor receptor antibody Cetuximab is reported to be ineffective in KRAS-mutant tumors. Mutation testing techniques have therefore become an urgent concern. We have compared three methods for detecting KRAS mutations in 59 cases of colon carcinoma: 1) high resolution melting, 2) the amplification refractory mutation system using a bifunctional self-probing primer (ARMS/Scorpion, ARMS/S), and 3) direct sequencing. We also evaluated the effects of the methods of sectioning and coring of paraffin blocks to obtain tumor DNA on assay sensitivity and specificity. The most sensitive and specific combination of block sampling and mutational analysis was ARMS/S performed on DNA derived from 1-mm paraffin cores. This combination of tissue sampling and testing method detected KRAS mutations in 46% of colon tumors. Four samples were positive by ARMS/S, but initially negative by direct sequencing. Cloned DNA samples were retested by direct sequencing, and in all four cases KRAS mutations were identified in the DNA. In six cases, high resolution melting abnormalities could not be confirmed as specific mutations either by ARMS/S or direct sequencing. We conclude that coring of the paraffin blocks and testing by ARMS/S is a sensitive, specific, and efficient method for KRAS testing. PMID:20007845

  8. Mutant Kras copy number defines metabolic reprogramming and therapeutic susceptibilities.

    PubMed

    Kerr, Emma M; Gaude, Edoardo; Turrell, Frances K; Frezza, Christian; Martins, Carla P

    2016-03-01

    The RAS/MAPK (mitogen-activated protein kinase) signalling pathway is frequently deregulated in non-small-cell lung cancer, often through KRAS activating mutations. A single endogenous mutant Kras allele is sufficient to promote lung tumour formation in mice but malignant progression requires additional genetic alterations. We recently showed that advanced lung tumours from Kras(G12D/+);p53-null mice frequently exhibit Kras(G12D) allelic enrichment (Kras(G12D)/Kras(wild-type) > 1) (ref. 7), implying that mutant Kras copy gains are positively selected during progression. Here we show, through a comprehensive analysis of mutant Kras homozygous and heterozygous mouse embryonic fibroblasts and lung cancer cells, that these genotypes are phenotypically distinct. In particular, Kras(G12D/G12D) cells exhibit a glycolytic switch coupled to increased channelling of glucose-derived metabolites into the tricarboxylic acid cycle and glutathione biosynthesis, resulting in enhanced glutathione-mediated detoxification. This metabolic rewiring is recapitulated in mutant KRAS homozygous non-small-cell lung cancer cells and in vivo, in spontaneous advanced murine lung tumours (which display a high frequency of Kras(G12D) copy gain), but not in the corresponding early tumours (Kras(G12D) heterozygous). Finally, we demonstrate that mutant Kras copy gain creates unique metabolic dependences that can be exploited to selectively target these aggressive mutant Kras tumours. Our data demonstrate that mutant Kras lung tumours are not a single disease but rather a heterogeneous group comprising two classes of tumours with distinct metabolic profiles, prognosis and therapeutic susceptibility, which can be discriminated on the basis of their relative mutant allelic content. We also provide the first, to our knowledge, in vivo evidence of metabolic rewiring during lung cancer malignant progression. PMID:26909577

  9. EGFR, HER-2 and KRAS in canine gastric epithelial tumors: a potential human model?

    PubMed

    Terragni, Rossella; Casadei Gardini, Andrea; Sabattini, Silvia; Bettini, Giuliano; Amadori, Dino; Talamonti, Chiara; Vignoli, Massimo; Capelli, Laura; Saunders, Jimmy H; Ricci, Marianna; Ricci, Marianna; Ulivi, Paola; Ulivi, Paola

    2014-01-01

    Epidermal growth factor receptor (EGFR or HER-1) and its analog c-erbB-2 (HER-2) are protein tyrosine kinases correlated with prognosis and response to therapy in a variety of human cancers. KRAS mediates the transduction of signals between EGFR and the nucleus, and its mutation has been identified as a predictor of resistance to anti-EGFR drugs. In human oncology, the importance of the EGFR/HER-2/KRAS signalling pathway in gastric cancer is well established, and HER-2 testing is required before initiating therapy. Conversely, this pathway has never been investigated in canine gastric tumours. A total of 19 canine gastric epithelial neoplasms (5 adenomas and 14 carcinomas) were retrospectively evaluated for EGFR/HER-2 immunohistochemical expression and KRAS mutational status. Five (35.7%) carcinomas were classified as intestinal-type and 9 (64.3%) as diffuse-type. EGFR was overexpressed (≥ 1+) in 8 (42.1%) cases and HER-2 (3+) in 11 (57.9%) cases, regardless of tumour location or biological behaviour. The percentage of EGFR-positive tumours was significantly higher in the intestinal-type (80%) than in the diffuse-type (11.1%, p = 0.023). KRAS gene was wild type in 18 cases, whereas one mucinous carcinoma harboured a point mutation at codon 12 (G12R). EGFR and HER-2 may be promising prognostic and therapeutic targets in canine gastric epithelial neoplasms. The potential presence of KRAS mutation should be taken into account as a possible mechanism of drug resistance. Further studies are necessary to evaluate the role of dog as a model for human gastric cancer. PMID:24454858

  10. EGFR, HER-2 and KRAS in Canine Gastric Epithelial Tumors: A Potential Human Model?

    PubMed Central

    Bettini, Giuliano; Amadori, Dino; Talamonti, Chiara; Vignoli, Massimo; Capelli, Laura; Saunders, Jimmy H.; Ricci, Marianna; Ulivi, Paola

    2014-01-01

    Epidermal growth factor receptor (EGFR or HER-1) and its analog c-erbB-2 (HER-2) are protein tyrosine kinases correlated with prognosis and response to therapy in a variety of human cancers. KRAS mediates the transduction of signals between EGFR and the nucleus, and its mutation has been identified as a predictor of resistance to anti-EGFR drugs. In human oncology, the importance of the EGFR/HER-2/KRAS signalling pathway in gastric cancer is well established, and HER-2 testing is required before initiating therapy. Conversely, this pathway has never been investigated in canine gastric tumours. A total of 19 canine gastric epithelial neoplasms (5 adenomas and 14 carcinomas) were retrospectively evaluated for EGFR/HER-2 immunohistochemical expression and KRAS mutational status. Five (35.7%) carcinomas were classified as intestinal-type and 9 (64.3%) as diffuse-type. EGFR was overexpressed (≥1+) in 8 (42.1%) cases and HER-2 (3+) in 11 (57.9%) cases, regardless of tumour location or biological behaviour. The percentage of EGFR-positive tumours was significantly higher in the intestinal-type (80%) than in the diffuse-type (11.1%, p = 0.023). KRAS gene was wild type in 18 cases, whereas one mucinous carcinoma harboured a point mutation at codon 12 (G12R). EGFR and HER-2 may be promising prognostic and therapeutic targets in canine gastric epithelial neoplasms. The potential presence of KRAS mutation should be taken into account as a possible mechanism of drug resistance. Further studies are necessary to evaluate the role of dog as a model for human gastric cancer. PMID:24454858

  11. KRAS-dependent sorting of miRNA to exosomes.

    PubMed

    Cha, Diana J; Franklin, Jeffrey L; Dou, Yongchao; Liu, Qi; Higginbotham, James N; Demory Beckler, Michelle; Weaver, Alissa M; Vickers, Kasey; Prasad, Nirpesh; Levy, Shawn; Zhang, Bing; Coffey, Robert J; Patton, James G

    2015-01-01

    Mutant KRAS colorectal cancer (CRC) cells release protein-laden exosomes that can alter the tumor microenvironment. To test whether exosomal RNAs also contribute to changes in gene expression in recipient cells, and whether mutant KRAS might regulate the composition of secreted microRNAs (miRNAs), we compared small RNAs of cells and matched exosomes from isogenic CRC cell lines differing only in KRAS status. We show that exosomal profiles are distinct from cellular profiles, and mutant exosomes cluster separately from wild-type KRAS exosomes. miR-10b was selectively increased in wild-type exosomes, while miR-100 was increased in mutant exosomes. Neutral sphingomyelinase inhibition caused accumulation of miR-100 only in mutant cells, suggesting KRAS-dependent miRNA export. In Transwell co-culture experiments, mutant donor cells conferred miR-100-mediated target repression in wild-type-recipient cells. These findings suggest that extracellular miRNAs can function in target cells and uncover a potential new mode of action for mutant KRAS in CRC. PMID:26132860

  12. Oncogenic KRAS and BRAF Drive Metabolic Reprogramming in Colorectal Cancer.

    PubMed

    Hutton, Josiah E; Wang, Xiaojing; Zimmerman, Lisa J; Slebos, Robbert J C; Trenary, Irina A; Young, Jamey D; Li, Ming; Liebler, Daniel C

    2016-09-01

    Metabolic reprogramming, in which altered utilization of glucose and glutamine supports rapid growth, is a hallmark of most cancers. Mutations in the oncogenes KRAS and BRAF drive metabolic reprogramming through enhanced glucose uptake, but the broader impact of these mutations on pathways of carbon metabolism is unknown. Global shotgun proteomic analysis of isogenic DLD-1 and RKO colon cancer cell lines expressing mutant and wild type KRAS or BRAF, respectively, failed to identify significant differences (at least 2-fold) in metabolic protein abundance. However, a multiplexed parallel reaction monitoring (PRM) strategy targeting 73 metabolic proteins identified significant protein abundance increases of 1.25-twofold in glycolysis, the nonoxidative pentose phosphate pathway, glutamine metabolism, and the phosphoserine biosynthetic pathway in cells with KRAS G13D mutations or BRAF V600E mutations. These alterations corresponded to mutant KRAS and BRAF-dependent increases in glucose uptake and lactate production. Metabolic reprogramming and glucose conversion to lactate in RKO cells were proportional to levels of BRAF V600E protein. In DLD-1 cells, these effects were independent of the ratio of KRAS G13D to KRAS wild type protein. A study of 8 KRAS wild type and 8 KRAS mutant human colon tumors confirmed the association of increased expression of glycolytic and glutamine metabolic proteins with KRAS mutant status. Metabolic reprogramming is driven largely by modest (<2-fold) alterations in protein expression, which are not readily detected by the global profiling methods most commonly employed in proteomic studies. The results indicate the superiority of more precise, multiplexed, pathway-targeted analyses to study functional proteome systems. Data are available through MassIVE Accession MSV000079486 at ftp://MSV000079486@massive.ucsd.edu. PMID:27340238

  13. Coordinate direct input of both KRAS and IGF1 receptor to activation of PI 3-kinase in KRAS mutant lung cancer

    PubMed Central

    Molina-Arcas, Miriam; Hancock, David C.; Sheridan, Clare; Kumar, Madhu S.; Downward, Julian

    2013-01-01

    SUMMARY Using a panel of non-small cell lung cancer (NSCLC) lines, we show here that MEK and RAF inhibitors are selectively toxic for the KRAS mutant genotype, while PI 3-kinase (PI3K), AKT and mTOR inhibitors are not. IGF1 receptor (IGF1R) tyrosine kinase inhibitors also show selectivity for KRAS mutant lung cancer lines. Combinations of IGF1R and MEK inhibitors resulted in strengthened inhibition of KRAS mutant lines and also showed improved effectiveness in autochthonous mouse models of Kras induced NSCLC. PI3K pathway activity is dependent on basal IGF1R activity in KRAS mutant, but not wild-type, lung cancer cell lines. KRAS is needed for both MEK and PI3K pathway activity in KRAS mutant, but not wild-type, lung cancer cells, while acute activation of KRAS causes stimulation of PI3K dependent upon IGF1R kinase activity. Coordinate direct input of both KRAS and IGF1R is thus required to activate PI3K in KRAS mutant lung cancer cells. PMID:23454899

  14. Utility of KRAS mutation detection using circulating cell-free DNA from patients with colorectal cancer.

    PubMed

    Yamada, Takeshi; Iwai, Takuma; Takahashi, Goro; Kan, Hayato; Koizumi, Michihiro; Matsuda, Akihisa; Shinji, Seiichi; Yamagishi, Aya; Yokoyama, Yasuyuki; Tatsuguchi, Atsushi; Kawagoe, Tatsuro; Kitano, Shiro; Nakayama, Masato; Matsumoto, Satoshi; Uchida, Eiji

    2016-07-01

    In this study, we evaluated the clinical utility of detecting KRAS mutations in circulating cell-free (ccf)DNA of metastatic colorectal cancer patients. We prospectively recruited 94 metastatic colorectal cancer patients. Circulating cell-free DNA was extracted from plasma samples and analyzed for the presence of seven KRAS point mutations. Using the Invader Plus assay with peptide nucleic acid clamping method and digital PCR, KRAS mutations were detected in the ccfDNA in 35 of 39 patients previously determined to have primary tumors containing KRAS mutations using the Luminex method, and in 5 of 55 patients with tumors containing wild-type KRAS. Curative resection was undertaken in 7 of 34 patients with primary and ccfDNA KRAS mutations, resulting in the disappearance of the mutation from the cell-free DNA in five of seven patients. Three of these patients had tumor recurrence and KRAS mutations in their ccfDNA reappeared. Epidermal growth factor receptor blockade was administered to 24 of the KRAS tumor wild-type patients. Of the 24 patients with wild-type KRAS in their primary tumors, three patients had KRAS mutations in their ccfDNA and did not respond to treatment with epidermal growth factor receptor (EGFR) blockade. We also detected a new KRAS mutation in five patients during chemotherapy with EGFR blockade, before disease progression was detectable with imaging. The detection of KRAS mutations in ccfDNA is an attractive approach for predicting both treatment response and acquired resistance to EGFR blockade, and for detecting disease recurrence. PMID:27116474

  15. Akt mediated ROS-dependent selective targeting of mutant KRAS tumors.

    PubMed

    Iskandar, Kartini; Rezlan, Majidah; Pervaiz, Shazib

    2014-10-01

    Reactive oxygen species (ROS) play a critical role in a variety of cellular processes, ranging from cell survival and proliferation to cell death. Previously, we reported the ability of a small molecule compound, C1, to induce ROS dependent autophagy associated apoptosis in human cancer cell lines and primary tumor cells (Wong C. et al. 2010). Our ongoing investigations have unraveled a hitherto undefined novel signaling network involving hyper-phosphorylation of Akt and Akt-mediated ROS production in cancer cell lines. Interestingly, drug-induced Akt activation is selectively seen in cell lines that carry mutant KRAS; HCT116 cells that carry the V13D KRAS mutation respond favorably to C1 while HT29 cells expressing wild type KRAS are relatively resistant. Of note, not only does the compound target mutant KRAS expressing cells but also induces RAS activation as evidenced by the PAK pull down assay. Corroborating this, pharmacological inhibition as well as siRNA mediated silencing of KRAS or Akt, blocked C1-induced ROS production and rescued tumor colony forming ability in HCT116 cells. To further confirm the involvement of KRAS, we made use of mutant KRAS transformed RWPE-1 prostate epithelial cells. Notably, drug-induced ROS generation and death sensitivity was significantly higher in RWPE-1-KRAS cells than the RWPE-1-vector cells, thus confirming the results obtained with mutant KRAS colorectal carcinoma cell line. Lastly, we made use of HCT116 mutant KRAS knockout cells (KO) where the mutant KRAS allele had been deleted, thus expressing a single wild-type KRAS allele. Exposure of the KO cells to C1 failed to induce Akt activation and mitochondrial ROS production. Taken together, results show the involvement of activated Akt in ROS-mediated selective targeting of mutant KRAS expressing tumors, which could have therapeutic implications given the paucity of chemotherapeutic strategies specifically targeting KRAS mutant cancers. PMID:26461287

  16. KRAS Engages AGO2 to Enhance Cellular Transformation.

    PubMed

    Shankar, Sunita; Pitchiaya, Sethuramasundaram; Malik, Rohit; Kothari, Vishal; Hosono, Yasuyuki; Yocum, Anastasia K; Gundlapalli, Harika; White, Yasmine; Firestone, Ari; Cao, Xuhong; Dhanasekaran, Saravana M; Stuckey, Jeanne A; Bollag, Gideon; Shannon, Kevin; Walter, Nils G; Kumar-Sinha, Chandan; Chinnaiyan, Arul M

    2016-02-16

    Oncogenic mutations in RAS provide a compelling yet intractable therapeutic target. Using co-immunoprecipitation mass spectrometry, we uncovered an interaction between RAS and Argonaute 2 (AGO2). Endogenously, RAS and AGO2 co-sediment and co-localize in the endoplasmic reticulum. The AGO2 N-terminal domain directly binds the Switch II region of KRAS, agnostic of nucleotide (GDP/GTP) binding. Functionally, AGO2 knockdown attenuates cell proliferation in mutant KRAS-dependent cells and AGO2 overexpression enhances KRAS(G12V)-mediated transformation. Using AGO2-/- cells, we demonstrate that the RAS-AGO2 interaction is required for maximal mutant KRAS expression and cellular transformation. Mechanistically, oncogenic KRAS attenuates AGO2-mediated gene silencing. Overall, the functional interaction with AGO2 extends KRAS function beyond its canonical role in signaling. PMID:26854235

  17. A combinatorial strategy for treating KRAS-mutant lung cancer.

    PubMed

    Manchado, Eusebio; Weissmueller, Susann; Morris, John P; Chen, Chi-Chao; Wullenkord, Ramona; Lujambio, Amaia; de Stanchina, Elisa; Poirier, John T; Gainor, Justin F; Corcoran, Ryan B; Engelman, Jeffrey A; Rudin, Charles M; Rosen, Neal; Lowe, Scott W

    2016-06-30

    Therapeutic targeting of KRAS-mutant lung adenocarcinoma represents a major goal of clinical oncology. KRAS itself has proved difficult to inhibit, and the effectiveness of agents that target key KRAS effectors has been thwarted by activation of compensatory or parallel pathways that limit their efficacy as single agents. Here we take a systematic approach towards identifying combination targets for trametinib, a MEK inhibitor approved by the US Food and Drug Administration, which acts downstream of KRAS to suppress signalling through the mitogen-activated protein kinase (MAPK) cascade. Informed by a short-hairpin RNA screen, we show that trametinib provokes a compensatory response involving the fibroblast growth factor receptor 1 (FGFR1) that leads to signalling rebound and adaptive drug resistance. As a consequence, genetic or pharmacological inhibition of FGFR1 in combination with trametinib enhances tumour cell death in vitro and in vivo. This compensatory response shows distinct specificities: it is dominated by FGFR1 in KRAS-mutant lung and pancreatic cancer cells, but is not activated or involves other mechanisms in KRAS wild-type lung and KRAS-mutant colon cancer cells. Importantly, KRAS-mutant lung cancer cells and patients’ tumours treated with trametinib show an increase in FRS2 phosphorylation, a biomarker of FGFR activation; this increase is abolished by FGFR1 inhibition and correlates with sensitivity to trametinib and FGFR inhibitor combinations. These results demonstrate that FGFR1 can mediate adaptive resistance to trametinib and validate a combinatorial approach for treating KRAS-mutant lung cancer. PMID:27338794

  18. Prognostic relevance of KRAS genotype in metastatic colorectal cancer patients unfit for FIr-B/FOx intensive regimen

    PubMed Central

    BRUERA, GEMMA; CANNITA, KATIA; GIORDANO, ALDO VICTOR; VICENTINI, ROBERTO; FICORELLA, CORRADO; RICEVUTO, ENRICO

    2014-01-01

    First-line triplet chemotherapy plus bevacizumab (FIr-B/FOx) can improve efficacy of metastatic colorectal cancer (MCRC), KRAS wild-type and mutant. Prognostic relevance of KRAS genotype was evaluated in patients unfit for FIr-B/FOx, treated with conventional medical treatments. Consecutive MCRC patients not eligible for FIr-B/FOx regimen due to age (≥75 years) and/or comorbidities were treated with tailored conventional first-line treatments. KRAS codon 12/13 mutations were screened by direct sequencing. Activity and efficacy were evaluated and compared according to medical treatments, age (non-elderly and elderly ≥65 years), comorbidity stage (Cumulative Illness Rating Scale), metastatic extension (liver-limited and other/multiple metastatic), and KRAS genotype, using log-rank. Selected first line treatments were medical in 37 patients (92.5%), and surgical in 3 patients (7.5%). Medical treatment regimens: triplet, 18 (45%); doublet, 15 (37.5%); mono-therapy, 4 (10%). At median follow-up of 8 months, objective response rate (ORR) was 37%, median progression-free survival (PFS) 7 months, liver metastasectomies 8% (liver-limited disease 37.5%), median overall survival (OS) 13 months. Triplet regimens failed to significantly affect clinical outcome, compared to doublet. According to KRAS genotype, ORR, PFS and OS were, respectively: wild-type 50%, 8 months, 13 months; mutant 25%, 6 months, 9 months. KRAS genotype wild-type compared to mutant significantly affected PFS, while not OS. KRAS c.35 G>A mutation (G12D) significantly affected worse PFS and OS compared to wild-type and/or other mutations. KRAS genotype, specifically the c.35 G>A KRAS mutation, may indicate poor prognosis in MCRC patients unfit for intensive medical treatments. PMID:24715238

  19. Direct inhibition of oncogenic KRAS by hydrocarbon-stapled SOS1 helices

    PubMed Central

    Leshchiner, Elizaveta S.; Parkhitko, Andrey; Bird, Gregory H.; Luccarelli, James; Bellairs, Joseph A.; Escudero, Silvia; Opoku-Nsiah, Kwadwo; Godes, Marina; Perrimon, Norbert; Walensky, Loren D.

    2015-01-01

    Activating mutations in the Kirsten rat sarcoma viral oncogene homolog (KRAS) underlie the pathogenesis and chemoresistance of ∼30% of all human tumors, yet the development of high-affinity inhibitors that target the broad range of KRAS mutants remains a formidable challenge. Here, we report the development and validation of stabilized alpha helices of son of sevenless 1 (SAH-SOS1) as prototype therapeutics that directly inhibit wild-type and mutant forms of KRAS. SAH-SOS1 peptides bound in a sequence-specific manner to KRAS and its mutants, and dose-responsively blocked nucleotide association. Importantly, this functional binding activity correlated with SAH-SOS1 cytotoxicity in cancer cells expressing wild-type or mutant forms of KRAS. The mechanism of action of SAH-SOS1 peptides was demonstrated by sequence-specific down-regulation of the ERK-MAP kinase phosphosignaling cascade in KRAS-driven cancer cells and in a Drosophila melanogaster model of Ras85DV12 activation. These studies provide evidence for the potential utility of SAH-SOS1 peptides in neutralizing oncogenic KRAS in human cancer. PMID:25624485

  20. Cten Is Targeted by Kras Signalling to Regulate Cell Motility in the Colon and Pancreas

    PubMed Central

    Al-Ghamdi, Saleh; Albasri, Abdulkader; Cachat, Julien; Ibrahem, Salih; Muhammad, Belal A.; Jackson, Darryl; Nateri, Abdolrahman S.; Kindle, Karin B.; Ilyas, Mohammad

    2011-01-01

    CTEN/TNS4 is an oncogene in colorectal cancer (CRC) which enhances cell motility although the mechanism of Cten regulation is unknown. We found an association between high Cten expression and KRAS/BRAF mutation in a series of CRC cell lines (p = 0.03) and hypothesised that Kras may regulate Cten. To test this, Kras was knocked-down (using small interfering (si)RNA) in CRC cell lines SW620 and DLD1 (high Cten expressors and mutant for KRAS). In each cell line, Kras knockdown was mirrored by down-regulation of Cten Since Kras signals through Braf, we tested the effect of Kras knockdown in CRC cell line Colo205 (which shows high Cten expression and is mutant for BRAF but wild type for KRAS). Cten levels were unaffected by Kras knockdown whilst Braf knockdown resulted in reduced Cten expression suggesting that Kras signals via Braf to regulate Cten. Quantification of Cten mRNA and protein analysis following proteasome inhibition suggested that regulation was of Cten transcription. Kras knockdown inhibited cell motility. To test whether this could be mediated through Cten, SW620 cells were co-transfected with Kras specific siRNAs and a Cten expression vector. Restoring Cten expression was able to restore cell motility despite Kras knockdown (transwell migration and wounding assay, p<0.001 for both). Since KRAS is mutated in many cancers, we investigated whether this relationship could be demonstrated in other tumour models. The experiments were repeated in the pancreatic cancer cell lines Colo357 & PSN-1(both high Cten expressors and mutant for KRAS). In both cell lines, Kras was shown to regulate Cten and forced expression of Cten was able to rescue loss of cell motility following Kras knockdown in PSN-1 (transwell migration assay, p<0.001). We conclude that, in the colon and pancreas, Cten is a downstream target of Kras and may be a mechanism through which Kras regulates of cell motility. PMID:21698197

  1. Loss of integrin alpha1beta1 ameliorates Kras-induced lung cancer.

    PubMed

    Macias-Perez, Ines; Borza, Corina; Chen, Xiwu; Yan, Xuexian; Ibanez, Raquel; Mernaugh, Glenda; Matrisian, Lynn M; Zent, Roy; Pozzi, Ambra

    2008-08-01

    The collagen IV binding receptor integrin alpha1beta1 has been shown to regulate lung cancer due to its proangiogenic properties; however, it is unclear whether this receptor also plays a direct role in promoting primary lung tumors. To investigate this possibility, integrin alpha1-null mice were crossed with KrasLA2 mice that carry an oncogenic mutation of the Kras gene (G12D) and develop spontaneous primary tumors with features of non-small cell lung cancer. We provide evidence that KrasLA2/alpha1-null mice have a decreased incidence of primary lung tumors and longer survival compared with KrasLA2/alpha1 wild-type controls. Tumors from KrasLA2/alpha1-null mice were also smaller, less vascularized, and exhibited reduced cell proliferation and increased apoptosis, as determined by proliferating cell nuclear antigen and terminal deoxynucleotidyl-transferase-mediated dUTP nick-end staining, respectively. Moreover, tumors from the KrasLA2/alpha1-null mice showed diminished extracellular signal-regulated kinase (ERK) but enhanced p38 mitogen-activated protein kinase activation. Primary lung tumor epithelial cells isolated from KrasLA2/alpha1-null mice showed a significant decrease in anchorage-independent colony formation, collagen-mediated cell proliferation, ERK activation, and, most importantly, tumorigenicity when injected into nude mice compared with KrasLA2/alpha1 wild-type tumor cells. These results indicate that loss of the integrin alpha1 subunit decreases the incidence and growth of lung epithelial tumors initiated by oncogenic Kras, suggesting that both Kras and integrin alpha1beta1 cooperate to drive the growth of non-small cell lung cancer in vivo. PMID:18676835

  2. Peroxisomes in wild-type and rosy mutant Drosophila melanogaster.

    PubMed Central

    Beard, M E; Holtzman, E

    1987-01-01

    This study shows that peroxisomes are abundant in the Malpighian tubule and gut of wild-type Oregon R Drosophila melanogaster and that the peroxisomal population of the rosy-506 eye-color mutant differs from that of the wild type. Catalase activity in wild-type flies is demonstrable in bodies of appearance and centrifugal behavior comparable to the peroxisomes of vertebrate tissues. Xanthine oxidase (xanthine:oxygen oxidoreductase, EC 1.1.3.22) activity of the Malpighian tubule of wild-type flies is demonstrable cytochemically in bodies like those containing catalase. The rosy-506 mutant flies, with a deletion in the structural gene for xanthine dehydrogenase (xanthine:NAD+ oxidoreductase, EC 1.1.1.204), lack cytochemically demonstrable peroxisomal xanthine oxidase activity. In addition, peroxisomes in the rosy-506 mutants show less intense cytochemical staining for catalase than those in wild-type flies, and biochemical assays indicate that catalase in the rosy mutant is much more accessible to substrate in the absence of detergent than in the wild type. Thus, the rosy-506 mutation appears to affect peroxisomes and may mimic aspects of the defects of peroxisomes in some human metabolic disorders. Images PMID:3118368

  3. Mutations of KRAS/NRAS/BRAF predict cetuximab resistance in metastatic colorectal cancer patients

    PubMed Central

    Hsu, Hung-Chih; Thiam, Tan Kien; Lu, Yen-Jung; Yeh, Chien Yuh; Tsai, Wen-Sy; You, Jeng Fu; Hung, Hsin Yuan; Tsai, Chi-Neu; Hsu, An; Chen, Hua-Chien; Chen, Shu-Jen; Yang, Tsai-Sheng

    2016-01-01

    Approximately 45% of metastatic colorectal cancer (mCRC) patients with wild-type KRAS exon 2 are resistant to cetuximab treatment. We set out to identify additional genetic markers that might predict the response to cetuximab treatment. Fifty-three wild-type KRAS exon 2 mCRC patients were treated with cetuximab/irinotecan-based chemotherapy as a first- or third-line therapy. The mutational statuses of 10 EGFR pathway genes were analyzed in primary tumors using next-generation sequencing. BRAF, PIK3CA, KRAS (exons 3 and 4), NRAS, PTEN, and AKT1 mutations were detected in 6, 6, 5, 4, 1, and 1 patient, respectively. Four of the BRAF mutations were non-V600 variants. Four tumors harbored multiple co-existing (complex) mutations. All patients with BRAF mutations or complex mutation patterns were cetuximab non-responders. All patients but one harboring KRAS, NRAS, or BRAF mutations were non-responders. Mutations in any one of these three genes were associated with a poor response rate (7.1%) and reduced survival (PFS = 8.0 months) compared to wild-type patients (74.4% and 11.6 months). Our data suggest that KRAS, NRAS, and BRAF mutations predict response to cetuximab treatment in mCRC patients. PMID:26989027

  4. Associations of Anthropometric Factors with KRAS and BRAF Mutation Status of Primary Colorectal Cancer in Men and Women: A Cohort Study

    PubMed Central

    Brändstedt, Jenny; Wangefjord, Sakarias; Nodin, Björn; Eberhard, Jakob; Sundström, Magnus; Manjer, Jonas; Jirström, Karin

    2014-01-01

    Obesity is a well-established risk factor for colorectal cancer (CRC), and accumulating evidence suggests a differential influence of sex and anthropometric factors on the molecular carcinogenesis of the disease. The aim of the present study was to investigate the relationship between height, weight, bodyfat percentage, waist- and hip circumference, waist-hip ratio (WHR), body mass index (BMI) and CRC risk according to KRAS and BRAF mutation status of the tumours, with particular reference to potential sex differences. KRAS and BRAF mutations were analysed by pyrosequencing in tumours from 494 incident CRC cases in the Malmö Diet and Cancer Study. Hazard ratios of CRC risk according to anthropometric factors and mutation status were calculated using multivariate Cox regression models. While all anthropometric measures except height were associated with an increased risk of KRAS-mutated tumours, only BMI was associated with an increased risk of KRAS wild type tumours overall. High weight, hip, waist, WHR and BMI were associated with an increased risk of BRAF wild type tumours, but none of the anthropometric factors were associated with risk of BRAF-mutated CRC, neither in the overall nor in the sex-stratified analysis. In men, several anthropometric measures were associated with both KRAS-mutated and KRAS wild type tumours. In women, only a high WHR was significantly associated with an increased risk of KRAS-mutated CRC. A significant interaction was found between sex and BMI with respect to risk of KRAS-mutated tumours. In men, all anthropometric factors except height were associated with an increased risk of BRAF wild type tumours, whereas in women, only bodyfat percentage was associated with an increased risk of BRAF wild type tumours. The results from this prospective cohort study further support an influence of sex and lifestyle factors on different pathways of colorectal carcinogenesis, defined by KRAS and BRAF mutation status of the tumours. PMID:24918610

  5. A comparison of four methods for detecting KRAS mutations in formalin-fixed specimens from metastatic colorectal cancer patients

    PubMed Central

    MATSUNAGA, MOTOTSUGU; KANETA, TOSHIKADO; MIWA, KEISUKE; ICHIKAWA, WATARU; FUJITA, KEN-ICHI; NAGASHIMA, FUMIO; FURUSE, JUNJI; KAGE, MASAYOSHI; AKAGI, YOSHITO; SASAKI, YASUTSUNA

    2016-01-01

    There is currently no standard method for the detection of Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation status in colorectal tumors. In the present study, we compared the KRAS mutation detection ability of four methods: direct sequencing, Scorpion-ARMS assaying, pyrosequencing and multi-analyte profiling (Luminex xMAP). We evaluated 73 cases of metastatic colorectal cancer (mCRC) resistant to irinotecan, oxaliplatin and fluoropyrimidine that were enrolled in an all-case study of cetuximab. The KRAS mutation detection capacity of the four analytical methods was compared using DNA samples extracted from tumor tissue, and the detection success rate and concordance of the detection results were evaluated. KRAS mutations were detected by direct sequencing, Scorpion-ARMS assays, pyrosequencing and Luminex xMAP at success rates of 93.2%, 97.3%, 95.9% and 94.5%, respectively. The concordance rates of the detection results by Scorpion-ARMS, pyrosequencing and Luminex xMAP with those of direct sequencing were 0.897, 0.923 and 0.900 (κ statistics), respectively. The direct sequencing method could not determine KRAS mutation status in five DNA samples. Of these, Scorpion-ARMS, pyrosequencing and Luminex xMAP successfully detected three, two and one KRAS mutation statuses, respectively. Three cases demonstrated inconsistent results, whereby Luminex xMAP detected mutated KRAS in two samples while wild-type KRAS was detected by the other methods. In the remaining case, direct sequencing detected wild-type KRAS, which was identified as mutated KRAS by the other methods. In conclusion, we confirmed that Scorpion-ARMS, pyrosequencing and Luminex xMAP were equally reliable in detecting KRAS mutation status in mCRC. However, in rare cases, the KRAS status was differentially diagnosed using these methods. PMID:27347117

  6. MUC1-C confers EMT and KRAS independence in mutant KRAS lung cancer cells

    PubMed Central

    Kharbanda, Akriti; Rajabi, Hasan; Jin, Caining; Alam, Maroof; Wong, Kwok-Kin; Kufe, Donald

    2014-01-01

    Non-small cell lung cancers (NSCLCs) that harbor an oncogenic KRAS mutation are often associated with resistance to targeted therapies. The MUC1-C transmembrane protein is aberrantly overexpressed in NSCLCs and confers a poor outcome; however, the functional role for MUC1-C in mutant KRAS NSCLC cells has remained unclear. The present studies demonstrate that silencing MUC1-C in A549/KRAS(G12S) and H460/KRAS(Q61H) NSCLC cells is associated with downregulation of AKT signaling and inhibition of growth. Overexpression of a MUC1-C(CQC→AQA) mutant, which inhibits MUC1-C homodimerization and function, suppressed both AKT and MEK activation. Moreover, treatment with GO-203, an inhibitor of MUC1-C homodimerization, blocked AKT and MEK signaling and decreased cell survival. The results further demonstrate that targeting MUC1-C suppresses expression of the ZEB1 transcriptional repressor by an AKT-mediated mechanism, and in turn induces miR-200c. In concert with these effects on the ZEB1/miR-200c regulatory loop, targeting MUC1-C was associated with reversal of the epithelial-mesenchymal transition (EMT) and inhibition of self-renewal capacity. Loss of MUC1-C function also attenuated KRAS independence and inhibited growth of KRAS mutant NSCLC cells as tumors in mice. These findings support a model in which targeting MUC1-C inhibits mutant KRAS signaling in NSCLC cells and thereby reverses the EMT phenotype and decreases self-renewal. PMID:25245423

  7. KRAS Mouse Models

    PubMed Central

    O’Hagan, Rónán C.; Heyer, Joerg

    2011-01-01

    KRAS is a potent oncogene and is mutated in about 30% of all human cancers. However, the biological context of KRAS-dependent oncogenesis is poorly understood. Genetically engineered mouse models of cancer provide invaluable tools to study the oncogenic process, and insights from KRAS-driven models have significantly increased our understanding of the genetic, cellular, and tissue contexts in which KRAS is competent for oncogenesis. Moreover, variation among tumors arising in mouse models can provide insight into the mechanisms underlying response or resistance to therapy in KRAS-dependent cancers. Hence, it is essential that models of KRAS-driven cancers accurately reflect the genetics of human tumors and recapitulate the complex tumor-stromal intercommunication that is manifest in human cancers. Here, we highlight the progress made in modeling KRAS-dependent cancers and the impact that these models have had on our understanding of cancer biology. In particular, the development of models that recapitulate the complex biology of human cancers enables translational insights into mechanisms of therapeutic intervention in KRAS-dependent cancers. PMID:21779503

  8. The K-Ras 4A isoform promotes apoptosis but does not affect either lifespan or spontaneous tumor incidence in aging mice

    SciTech Connect

    Plowman, Sarah J.; Arends, Mark J.; Brownstein, David G.; Luo Feijun; Devenney, Paul S.; Rose, Lorraine; Ritchie, Ann-Marie; Berry, Rachel L.; Harrison, David J.; Hooper, Martin L.; Patek, Charles E. . E-mail: Charles.Patek@ed.ac.uk

    2006-01-01

    Ras proteins function as molecular switches in signal transduction pathways, and, here, we examined the effects of the K-ras4A and 4B splice variants on cell function by comparing wild-type embryonic stem (ES) cells with K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} (exon 4A knock-out) ES cells which express K-ras4B only and K-ras {sup -/-} (exons 1-3 knock-out) ES cells which express neither splice variant, and intestinal epithelium from wild-type and K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} mice. RT-qPCR analysis found that K-ras4B expression was reduced in K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} ES cells but unaffected in small intestine. K-Ras deficiency did not affect ES cell growth, and K-Ras4A deficiency did not affect intestinal epithelial proliferation. K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} and K-ras {sup -/-} ES cells showed a reduced capacity for differentiation following LIF withdrawal, and K-ras {sup -/-} cells were least differentiated. K-Ras4A deficiency inhibited etoposide-induced apoptosis in ES cells and intestinal epithelial cells. However, K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} ES cells were more resistant to etoposide-induced apoptosis than K-ras {sup -/-} cells. The results indicate that (1) K-Ras4A promotes apoptosis while K-Ras4B inhibits it, and (2) K-Ras4B, and possibly K-Ras4A, promotes differentiation. The findings raise the possibility that alteration of the K-Ras4A/4B isoform ratio modulates tumorigenesis by differentially affecting stem cell survival and/or differentiation. However, K-Ras4A deficiency did not affect life expectancy or spontaneous overall tumor incidence in aging mice.

  9. Mathematical modeling of drug resistance due to KRAS mutation in colorectal cancer.

    PubMed

    Sameen, Sheema; Barbuti, Roberto; Milazzo, Paolo; Cerone, Antonio; Del Re, Marzia; Danesi, Romano

    2016-01-21

    The most challenging task in colorectal cancer research nowadays is to understand the development of acquired resistance to anti-EGFR drugs. The key reason for this problem is the KRAS mutations appearance after the treatment with monoclonal antibodies (moAb). Here we present a mathematical model for the analysis of KRAS mutations behavior in colorectal cancer with respect to moAb treatments. To evaluate the drug performance we have developed equations for two types of tumors cells, KRAS mutated and KRAS wild-type. Both tumor cell populations were treated with a combination of moAb and chemotherapy drugs. It was observed that even the minimal initial concentration of KRAS mutation before the treatment has the ability to make the tumor refractory to the treatment. Minor population of KRAS mutations has strong influence on large number of wild-type cells as well rendering them resistant to chemotherapy. Patient׳s immune responses are specifically taken into considerations and it is found that, in case of KRAS mutations, the immune strength does not affect medication efficacy. Finally, cetuximab (moAb) and irinotecan (chemotherapy) drugs are analyzed as first-line treatment of colorectal cancer with few KRAS mutated cells. Results show that this combined treatment could be only effective for patients with high immune strengths and it should not be recommended as first-line therapy for patients with moderate immune strengths or weak immune systems because of a potential risk of relapse, with KRAS mutant cells acquired resistance involved with them. PMID:26551156

  10. KRAS Genotypic Changes of Circulating Tumor Cells during Treatment of Patients with Metastatic Colorectal Cancer

    PubMed Central

    Kalikaki, Aristea; Politaki, Helen; Souglakos, John; Apostolaki, Stella; Papadimitraki, Elisavet; Georgoulia, Nefeli; Tzardi, Maria; Mavroudis, Dimitris; Georgoulias, Vassilis; Voutsina, Alexandra

    2014-01-01

    Introduction Circulating tumor cells (CTCs) could represent a non-invasive source of cancer cells used for longitudinal monitoring of the tumoral mutation status throughout the course of the disease. The aims of the present study were to investigate the detection of KRAS mutations in CTCs from patients with metastatic colorectal cancer (mCRC) and to compare their mutation status during treatment or disease progression with that of the corresponding primary tumors. Materials and Methods Identification of the seven most common KRAS mutations on codons 12 and 13 was performed by Peptide Nucleic Acid (PNA)-based qPCR method. The sensitivity of the assay was determined after isolation of KRAS mutant cancer cells spiked into healthy donors' blood, using the CellSearch Epithelial Cell kit. Consistent detection of KRAS mutations was achieved in samples containing at least 10 tumor cells/7.5 ml of blood. Results The clinical utility of the assay was assessed in 48 blood samples drawn from 31 patients with mCRC. All patients had PIK3CA and BRAF wild type primary tumors and 14 KRAS mutant tumors. CTCs were detected in 65% of specimens obtained from 74% of patients. KRAS mutation analysis in CTC-enriched specimens showed that 45% and 16.7% of patients with mutant and wild type primary tumors, respectively, had detectable mutations in their CTCs. Assessing KRAS mutations in serial blood samples revealed that individual patient's CTCs exhibited different mutational status of KRAS during treatment. Conclusions The current findings support the rationale for using the CTCs as a dynamic source of tumor cells which, by re-evaluating their KRAS mutation status, could predict, perhaps more accurately, the response of mCRC patients to targeted therapy. PMID:25137394

  11. Endocytic trafficking routes of wild type and DeltaF508 cystic fibrosis transmembrane conductance regulator.

    PubMed

    Gentzsch, Martina; Chang, Xiu-Bao; Cui, Liying; Wu, Yufeng; Ozols, Victor V; Choudhury, Amit; Pagano, Richard E; Riordan, John R

    2004-06-01

    Intracellular trafficking of cystic fibrosis transmembrane conductance regulator (CFTR) is a focus of attention because it is defective in most patients with cystic fibrosis. DeltaF508 CFTR, which does not mature conformationally, normally does not exit the endoplasmic reticulum, but if induced to do so at reduced temperature is short-lived at the surface. We used external epitope-tagged constructs to elucidate the itinerary and kinetics of wild type and DeltaF508 CFTR in the endocytic pathway and visualized movement of CFTR from the surface to intracellular compartments. Modulation of different endocytic steps with low temperature (16 degrees C) block, protease inhibitors, and overexpression of wild type and mutant Rab GTPases revealed that surface CFTR enters several different routes, including a Rab5-dependent initial step to early endosomes, then either Rab11-dependent recycling back to the surface or Rab7-regulated movement to late endosomes or alternatively Rab9-mediated transit to the trans-Golgi network. Without any of these modulations DeltaF508 CFTR rapidly disappears from and does not return to the cell surface, confirming that its altered structure is detected in the distal as well as proximal secretory pathway. Importantly, however, the mutant protein can be rescued at the plasma membrane by Rab11 overexpression, proteasome inhibitors, or inhibition of Rab5-dependent endocytosis. PMID:15075371

  12. AGGREGATED, WILD-TYPE PRION PROTEIN CAUSES NEUROLOGICAL DYSFUNCTION AND SYNAPTIC ABNORMALITIES

    PubMed Central

    Chiesa, Roberto; Piccardo, Pedro; Biasini, Emiliano; Ghetti, Bernardino; Harris, David A.

    2008-01-01

    The neurotoxic forms of the prion protein (PrP) that cause neurodegeneration in prion diseases remain to be conclusively identified. Considerable evidence points to the importance of non-infectious oligomers of PrP in the pathogenic process. In this study, we describe lines of Tg(WT) transgenic mice that over-express wild-type PrP by either ∼5-fold or ∼10-fold (depending on whether the transgene array is, respectively, hemizygous or homozygous). Homozygous but not hemizygous Tg(WT) mice develop a spontaneous neurodegenerative illness characterized clinically by tremor and paresis. Both kinds of mice accumulate large numbers of punctate PrP deposits in the molecular layer of the cerebellum as well as in several other brain regions, and they display abnormally enlarged synaptic terminals accompanied by a dramatic proliferation of membranous structures. The over-expressed PrP in Tg(WT) mice assembles into an insoluble form that is mildly protease-resistant and is recognizable by aggregation-specific antibodies, but that is not infectious in transmission experiments. Taken together, our results demonstrate that non-infectious aggregates of wild-type PrP are neurotoxic, particularly to synapses, and they suggest common pathogenic mechanisms shared by prion diseases and non-transmissible neurodegenerative disorders associated with protein misfolding. PMID:19052217

  13. Functional signaling pathway analysis of lung adenocarcinomas identifies novel therapeutic targets for KRAS mutant tumors

    PubMed Central

    Baldelli, Elisa; Bellezza, Guido; Haura, Eric B.; Crinó, Lucio; Cress, W. Douglas; Deng, Jianghong; Ludovini, Vienna; Sidoni, Angelo; Schabath, Matthew B.; Puma, Francesco; Vannucci, Jacopo; Siggillino, Annamaria; Liotta, Lance A.; Petricoin, Emanuel F.; Pierobon, Mariaelena

    2015-01-01

    Little is known about the complex signaling architecture of KRAS and the interconnected RAS-driven protein-protein interactions, especially as it occurs in human clinical specimens. This study explored the activated and interconnected signaling network of KRAS mutant lung adenocarcinomas (AD) to identify novel therapeutic targets. Thirty-four KRAS mutant (MT) and twenty-four KRAS wild-type (WT) frozen biospecimens were obtained from surgically treated lung ADs. Samples were subjected to laser capture microdissection and reverse phase protein microarray analysis to explore the expression/activation levels of 150 signaling proteins along with co-activation concordance mapping. An independent set of 90 non-small cell lung cancers (NSCLC) was used to validate selected findings by immunohistochemistry (IHC). Compared to KRAS WT tumors, the signaling architecture of KRAS MT ADs revealed significant interactions between KRAS downstream substrates, the AKT/mTOR pathway, and a number of Receptor Tyrosine Kinases (RTK). Approximately one-third of the KRAS MT tumors had ERK activation greater than the WT counterpart (p<0.01). Notably 18% of the KRAS MT tumors had elevated activation of the Estrogen Receptor alpha (ER-α) (p=0.02). This finding was verified in an independent population by IHC (p=0.03). KRAS MT lung ADs appear to have a more intricate RAS linked signaling network than WT tumors with linkage to many RTKs and to the AKT-mTOR pathway. Combination therapy targeting different nodes of this network may be necessary to treat this group of patients. In addition, for patients with KRAS MT tumors and activation of the ER-α, anti-estrogen therapy may have important clinical implications. PMID:26468985

  14. KRAS Mutation in Small Cell Lung Carcinoma and Extrapulmonary Small Cell Cancer

    PubMed Central

    Kodaz, Hilmi; Taştekin, Ebru; Erdoğan, Bülent; Hacıbekiroğlu, İlhan; Tozkır, Hilmi; Gürkan, Hakan; Türkmen, Esma; Demirkan, Bora; Uzunoğlu, Sernaz; Çiçin, İrfan

    2016-01-01

    Background: Lung cancer is one of the most lethal cancers. It is mainly classified into 2 groups: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Extrapulmonary small cell carcinomas (EPSCC) are very rare. The Ras oncogene controls most of the cellular functions in the cell. Overall, 21.6% of human cancers contain a Kirsten Ras (KRAS) mutation. SCLC and EPSCC have several similar features but their clinical course is different. Aims: We investigated the KRAS mutation status in SCLC and EPSCC. Study design: Mutation research. Methods: Thirty-seven SCLC and 15 EPSCC patients were included in the study. The pathological diagnoses were confirmed by a second pathologist. KRAS analysis was performed in our medical genetic department. DNA isolation was performed with primary tumor tissue using the QIAamp DNA FFPE Tissue kit (Qiagen; Hilden, Germany) in all patients. The therascreen KRAS Pyro Kit 24 V1 (Qiagen; Hilden, Germany) was used for KRAS analyses. Results: Thirty-four (91.9%) of the SCLC patients were male, while 11 (73.3%) of the EPSCC l patients were female. SCLC was more common in males, and EPSCC in females (p=0.001). A KRAS mutation was found in 6 (16.2%) if SCLC patients. The most common mutation was Q61R (CAA>CGA). Among the 15 EPSCC patients, 2 had a KRAS mutation (13.3%). When KRAS mutant and wild type patients were compared in the SCLC group, no difference was found for overall survival (p=0.6). Conclusion: In previous studies, the incidence of KRAS mutation in SCLC was 1–3%; however, it was 16.2% in our study. Therefore, there may be ethnic and geographical differences in the KRAS mutations of SCLC. As a result, KRAS mutation should not be excluded in SCLC.

  15. Functional signaling pathway analysis of lung adenocarcinomas identifies novel therapeutic targets for KRAS mutant tumors.

    PubMed

    Baldelli, Elisa; Bellezza, Guido; Haura, Eric B; Crinó, Lucio; Cress, W Douglas; Deng, Jianghong; Ludovini, Vienna; Sidoni, Angelo; Schabath, Matthew B; Puma, Francesco; Vannucci, Jacopo; Siggillino, Annamaria; Liotta, Lance A; Petricoin, Emanuel F; Pierobon, Mariaelena

    2015-10-20

    Little is known about the complex signaling architecture of KRAS and the interconnected RAS-driven protein-protein interactions, especially as it occurs in human clinical specimens. This study explored the activated and interconnected signaling network of KRAS mutant lung adenocarcinomas (AD) to identify novel therapeutic targets.Thirty-four KRAS mutant (MT) and twenty-four KRAS wild-type (WT) frozen biospecimens were obtained from surgically treated lung ADs. Samples were subjected to Laser Capture Microdissection and Reverse Phase Protein Microarray analysis to explore the expression/activation levels of 150 signaling proteins along with co-activation concordance mapping. An independent set of 90 non-small cell lung cancers (NSCLC) was used to validate selected findings by immunohistochemistry (IHC).Compared to KRAS WT tumors, the signaling architecture of KRAS MT ADs revealed significant interactions between KRAS downstream substrates, the AKT/mTOR pathway, and a number of Receptor Tyrosine Kinases (RTK). Approximately one-third of the KRAS MT tumors had ERK activation greater than the WT counterpart (p<0.01). Notably 18% of the KRAS MT tumors had elevated activation of the Estrogen Receptor alpha (ER-α) (p=0.02).This finding was verified in an independent population by IHC (p=0.03).KRAS MT lung ADs appear to have a more intricate RAS linked signaling network than WT tumors with linkage to many RTKs and to the AKT-mTOR pathway. Combination therapy targeting different nodes of this network may be necessary to treat this group of patients. In addition, for patients with KRAS MT tumors and activation of the ER-α, anti-estrogen therapy may have important clinical implications. PMID:26468985

  16. Novel Methodology for Rapid Detection of KRAS Mutation Using PNA-LNA Mediated Loop-Mediated Isothermal Amplification.

    PubMed

    Itonaga, Masahiro; Matsuzaki, Ibu; Warigaya, Kenji; Tamura, Takaaki; Shimizu, Yuki; Fujimoto, Masakazu; Kojima, Fumiyoshi; Ichinose, Masao; Murata, Shin-Ichi

    2016-01-01

    Detecting point mutation of human cancer cells quickly and accurately is gaining in importance for pathological diagnosis and choice of therapeutic approach. In the present study, we present novel methodology, peptide nucleic acid-locked nucleic acid mediated loop-mediated isothermal amplification (PNA-LNA mediated LAMP), for rapid detection of KRAS mutation using advantages of both artificial DNA and LAMP. PNA-LNA mediated LAMP reactions occurred under isothermal temperature conditions of with 4 primary primers set for the target regions on the KRAS gene, clamping PNA probe that was complimentary to the wild type sequence and LNA primers complementary to the mutated sequences. PNA-LNA mediated LAMP was applied for cDNA from 4 kinds of pancreatic carcinoma cell lines with or without KRAS point mutation. The amplified DNA products were verified by naked-eye as well as a real-time PCR equipment. By PNA-LNA mediated LAMP, amplification of wild type KRAS DNA was blocked by clamping PNA probe, whereas, mutant type KRAS DNA was significantly amplified within 50 min. Mutant alleles could be detected in samples which diluted until 0.1% of mutant-to-wild type ratio. On the other hand, mutant alleles could be reproducibly with a mutant-to-wild type ratio of 30% by direct sequencing and of 1% by PNA-clamping PCR. The limit of detection (LOD) of PNA-LNA mediated LAMP was much lower than the other conventional methods. Competition of LNA clamping primers complementary to two different subtypes (G12D and G12V) of mutant KRAS gene indicated different amplification time depend on subtypes of mutant cDNA. PNA-LNA mediated LAMP is a simple, rapid, specific and sensitive methodology for the detection of KRAS mutation. PMID:26999437

  17. Novel Methodology for Rapid Detection of KRAS Mutation Using PNA-LNA Mediated Loop-Mediated Isothermal Amplification

    PubMed Central

    Warigaya, Kenji; Tamura, Takaaki; Shimizu, Yuki; Fujimoto, Masakazu; Kojima, Fumiyoshi; Ichinose, Masao; Murata, Shin-ichi

    2016-01-01

    Detecting point mutation of human cancer cells quickly and accurately is gaining in importance for pathological diagnosis and choice of therapeutic approach. In the present study, we present novel methodology, peptide nucleic acid—locked nucleic acid mediated loop-mediated isothermal amplification (PNA-LNA mediated LAMP), for rapid detection of KRAS mutation using advantages of both artificial DNA and LAMP. PNA-LNA mediated LAMP reactions occurred under isothermal temperature conditions of with 4 primary primers set for the target regions on the KRAS gene, clamping PNA probe that was complimentary to the wild type sequence and LNA primers complementary to the mutated sequences. PNA-LNA mediated LAMP was applied for cDNA from 4 kinds of pancreatic carcinoma cell lines with or without KRAS point mutation. The amplified DNA products were verified by naked-eye as well as a real-time PCR equipment. By PNA-LNA mediated LAMP, amplification of wild type KRAS DNA was blocked by clamping PNA probe, whereas, mutant type KRAS DNA was significantly amplified within 50 min. Mutant alleles could be detected in samples which diluted until 0.1% of mutant-to-wild type ratio. On the other hand, mutant alleles could be reproducibly with a mutant-to-wild type ratio of 30% by direct sequencing and of 1% by PNA-clamping PCR. The limit of detection (LOD) of PNA-LNA mediated LAMP was much lower than the other conventional methods. Competition of LNA clamping primers complementary to two different subtypes (G12D and G12V) of mutant KRAS gene indicated different amplification time depend on subtypes of mutant cDNA. PNA-LNA mediated LAMP is a simple, rapid, specific and sensitive methodology for the detection of KRAS mutation. PMID:26999437

  18. KRAS G12D Mutation Subtype Is A Prognostic Factor for Advanced Pancreatic Adenocarcinoma

    PubMed Central

    Bournet, Barbara; Muscari, Fabrice; Buscail, Camille; Assenat, Eric; Barthet, Marc; Hammel, Pascal; Selves, Janick; Guimbaud, Rosine; Cordelier, Pierre; Buscail, Louis

    2016-01-01

    Objectives: There is no molecular biomarker available in the clinical practice to assess the prognosis of advanced pancreatic carcinoma. This multicenter prospective study aimed to investigate the role of KRAS mutation subtypes within the primary tumor to determine the prognosis of advanced pancreatic cancer. Methods: The exon-2 KRAS mutation status was tested on endoscopic ultrasound-guided fine-needle aspiration biopsy material (primary tumor; restriction fragment-length polymorphism plus sequencing and TaqMan allelic discrimination) of patients with proven locally advanced and/or metastatic pancreatic ductal carcinoma. We used the Kaplan–Meier method, log-rank test, and Cox's model to evaluate the impact of KRAS status on the overall survival (OS), adjusting for age, stage of disease, clinical performance status, CA 19-9 levels, and treatment. Results: A total of 219 patients (men: 116; mean age: 67±9.4 years) were included: 147 harbored a codon-12 KRAS mutation (G12D: 73; G12V: 53; G12R: 21) and 72 had a wild-type KRAS. There was no difference in the OS between patients with a mutant KRAS (8 months; 95% confidence interval (95% CI): 8.7–12.3) and the wild-type (9 months; 95% CI: 8.7–12.8; hazard ratio (HR): 1.03; P=0.82). However, the patients with a G12D mutation had a significantly shorter OS (6 months; 95% CI: 6.4–9.7) compared with the other patients (OS: 9 months; 95% CI: 10–13; HR: 1.47; P=0.003; i.e., wild type: 9 months, G12V: 9 months, G12R: 14 months). Similar results were observed in the subgroup of 162 patients who received chemotherapy (HR: 1.66; P=0.0013; G12D (n=49): 8 months, wild type (n=56): 10 months, G12V (n=38): 10 months, G12R (n=19): 14 months). Multivariate analyses identified KRAS G12D as an independent predictor for worse prognosis within the entire series (HR: 1.44; P=0.01) and in the subgroup of patients that received chemotherapy (HR: 1.84; P=0.02). Conclusions: The KRAS G12D mutation subtype is an independent prognostic

  19. Picoliter droplet-based digital peptide nucleic acid clamp PCR and dielectric sorting for low abundant K-ras mutations

    NASA Astrophysics Data System (ADS)

    Zhang, Huidan; Sperling, Ralph; Rotem, Assaf; Shan, Lianfeng; Heyman, John; Zhang, Yizhe; Weitz, David

    2012-02-01

    Colorectal cancer (CRC) remains the second leading cause of cancer-related mortality in the US, and the 5-year survival of metastatic CRC (mCRC) is less than 10%. Although monoclonal antibodies against epidermal growth factor receptor (EGFR) provide incremental improvements in survival, approximately 40% of mCRC patients with activating KRAS mutations won't benefit from this therapy. Peptide nucleic acid (PNA), a synthetic non-extendable oligonucleotides, can bind strongly to completely complementary wild-type KRAS by Watson-Crick base pairing and suppress its amplification during PCR, while any mutant allele will show unhindered amplification. The method is particularly suitable for the simultaneously detection of several adjoining mutant sites, just as mutations of codons 12 and 13 of KRAS gene where there are totally 12 possible mutation types. In this work, we describe the development and validation of this method, based on the droplet-based digital PCR. Using a microfluidic system, single target DNA molecule is compartmentalized in microdroplets together with PNA specific for wild-type KRAS, thermocycled and the fluorescence of each droplet was detected, followed by sorting and sequencing. It enables the precise determination of all possible mutant KRAS simultaneously, and the precise quantification of a single mutated KRAS in excess background unmutated KRAS.

  20. Absence of K-Ras Reduces Proliferation and Migration But Increases Extracellular Matrix Synthesis in Fibroblasts.

    PubMed

    Muñoz-Félix, José M; Fuentes-Calvo, Isabel; Cuesta, Cristina; Eleno, Nélida; Crespo, Piero; López-Novoa, José M; Martínez-Salgado, Carlos

    2016-10-01

    The involvement of Ras-GTPases in the development of renal fibrosis has been addressed in the last decade. We have previously shown that H- and N-Ras isoforms participate in the regulation of fibrosis. Herein, we assessed the role of K-Ras in cellular processes involved in the development of fibrosis: proliferation, migration, and extracellular matrix (ECM) proteins synthesis. K-Ras knockout (KO) mouse embryonic fibroblasts (K-ras(-/-) ) stimulated with transforming growth factor-β1 (TGF-β1) exhibited reduced proliferation and impaired mobility than wild-type fibroblasts. Moreover, an increase on ECM production was observed in K-Ras KO fibroblasts in basal conditions. The absence of K-Ras was accompanied by reduced Ras activation and ERK phosphorylation, and increased AKT phosphorylation, but no differences were observed in TGF-β1-induced Smad signaling. The MEK inhibitor U0126 decreased cell proliferation independently of the presence of K-ras but reduced migration and ECM proteins expression only in wild-type fibroblasts, while the PI3K-AKT inhibitor LY294002 decreased cell proliferation, migration, and ECM synthesis in both types of fibroblasts. Thus, our data unveil that K-Ras and its downstream effector pathways distinctively regulate key biological processes in the development of fibrosis. Moreover, we show that K-Ras may be a crucial mediator in TGF-β1-mediated effects in this cell type. J. Cell. Physiol. 231: 2224-2235, 2016. © 2016 Wiley Periodicals, Inc. PMID:26873620

  1. HER2 overexpression and amplification as a potential therapeutic target in colorectal cancer: analysis of 3256 patients enrolled in the QUASAR, FOCUS and PICCOLO colorectal cancer trials.

    PubMed

    Richman, Susan D; Southward, Katie; Chambers, Philip; Cross, Debra; Barrett, Jennifer; Hemmings, Gemma; Taylor, Morag; Wood, Henry; Hutchins, Gordon; Foster, Joseph M; Oumie, Assa; Spink, Karen G; Brown, Sarah R; Jones, Marc; Kerr, David; Handley, Kelly; Gray, Richard; Seymour, Matthew; Quirke, Philip

    2016-03-01

    HER2 overexpression/amplification is linked to trastuzumab response in breast/gastric cancers. One suggested anti-EGFR resistance mechanism in colorectal cancer (CRC) is aberrant MEK-AKT pathway activation through HER2 up-regulation. We assessed HER2-amplification/overexpression in stage II-III and IV CRC patients, assessing relationships to KRAS/BRAF and outcome. Pathological material was obtained from 1914 patients in the QUASAR stage II-III trial and 1342 patients in stage IV trials (FOCUS and PICCOLO). Tissue microarrays were created for HER2 immunohistochemistry. HER2-amplification was assessed using FISH and copy number variation. KRAS/BRAF mutation status was assessed by pyrosequencing. Progression-free survival (PFS) and overall survival (OS) data were obtained for FOCUS/PICCOLO and recurrence and mortality for QUASAR; 29/1342 (2.2%) stage IV and 25/1914 (1.3%) stage II-III tumours showed HER2 protein overexpression. Of the HER2-overexpressing cases, 27/28 (96.4%) stage IV tumours and 20/24 (83.3%) stage II-III tumours demonstrated HER2 amplification by FISH; 41/47 (87.2%) also showed copy number gains. HER2-overexpression was associated with KRAS/BRAF wild-type (WT) status at all stages: in 5.2% WT versus 1.0% mutated tumours (p < 0.0001) in stage IV and 2.1% versus 0.2% in stage II-III tumours (p = 0.01), respectively. HER2 was not associated with OS or PFS. At stage II-III, there was no significant correlation between HER2 overexpression and 5FU/FA response. A higher proportion of HER2-overexpressing cases experienced recurrence, but the difference was not significant. HER2-amplification/overexpression is identifiable by immunohistochemistry, occurring infrequently in stage II-III CRC, rising in stage IV and further in KRAS/BRAF WT tumours. The value of HER2-targeted therapy in patients with HER2-amplified CRC must be tested in a clinical trial. © 2015 The Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society

  2. CDK1 Is a Synthetic Lethal Target for KRAS Mutant Tumours

    PubMed Central

    Costa-Cabral, Sara; Brough, Rachel; Konde, Asha; Aarts, Marieke; Campbell, James; Marinari, Eliana; Riffell, Jenna; Bardelli, Alberto; Torrance, Christopher; Lord, Christopher J.; Ashworth, Alan

    2016-01-01

    Activating KRAS mutations are found in approximately 20% of human cancers but no RAS-directed therapies are currently available. Here we describe a novel, robust, KRAS synthetic lethal interaction with the cyclin dependent kinase, CDK1. This was discovered using parallel siRNA screens in KRAS mutant and wild type colorectal isogenic tumour cells and subsequently validated in a genetically diverse panel of 26 colorectal and pancreatic tumour cell models. This established that the KRAS/CDK1 synthetic lethality applies in tumour cells with either amino acid position 12 (p.G12V, pG12D, p.G12S) or amino acid position 13 (p.G13D) KRAS mutations and can also be replicated in vivo in a xenograft model using a small molecule CDK1 inhibitor. Mechanistically, CDK1 inhibition caused a reduction in the S-phase fraction of KRAS mutant cells, an effect also characterised by modulation of Rb, a master control of the G1/S checkpoint. Taken together, these observations suggest that the KRAS/CDK1 interaction is a robust synthetic lethal effect worthy of further investigation. PMID:26881434

  3. Expression of wild-type and mutant simian virus 40 large tumor antigens in villus-associated enterocytes of transgenic mice.

    PubMed Central

    Kim, S H; Roth, K A; Coopersmith, C M; Pipas, J M; Gordon, J I

    1994-01-01

    The four principal gut epithelial cell lineages undergo continuous and rapid renewal during a geographically well-organized migration along the crypt-to-villus axis. The molecules that regulate their proliferation and differentiation programs are largely unknown. The large tumor antigen (TAg) of wild-type (wt) simian virus 40 (SV40) and its mutant derivatives represent tools for describing the contributions of regulators of the cell cycle to the proliferative state of each lineage. Expression of SV40 TAgwt in postmitotic, villus-associated enterocytes of transgenic mice causes them to reenter the cell cycle without an apparent effect on their state of differentiation. When human KRAS with a Val-12 substitution ([Val12]KRAS) is coexpressed with SV40 TAgwt in villus enterocytes of bitransgenic animals, the two oncoproteins cooperate to produce dedifferentiation (dysplasia). SV40 mutant d11137 expresses a TAg that is unable to complex with p53 but retains N-terminal transforming functions, including the ability to complex pRB, p107, and p300. When SV40 TAgd11137 is expressed in villus enterocytes, they reenter into the cell cycle. However, coexpression of SV40 TAgd11137 and [Val12]KRAS does not produce dysplastic changes. Thus, the N-terminal 121 residues of TAg are sufficient to perturb the proliferative state of the enterocyte but not to produce detectable changes in the state of differentiation when coexpressed with [Val12]KRAS. Images PMID:8041720

  4. Detection of K-ras Mutations in Predicting Efficacy of Epidermal Growth Factor Receptor Tyrosine Kinase (EGFR-TK) Inhibitor in Patients with Metastatic Colorectal Cancer

    PubMed Central

    Li, Ze; Liu, Xue-Wei; Chi, Zhao-Cheng; Sun, Bao-Sheng; Cheng, Ying; Cheng, Long-Wei

    2015-01-01

    Epidermal growth factor receptor tyrosine kinase (EGFR-TK) inhibitors are useful in treating different advanced human cancers; however, their clinical efficacy varies. This study detected K-ras mutations to predict the efficacy of EGFR-TK inhibitor cetuximab treatment on Chinese patients with metastatic colorectal cancer (mCRC). A total of 87 patients with metastatic colorectal cancer were treated with cetuximab for 2-16 months, in combination with chemotherapy between August 2008 and July 2012, and tissue samples were used to detect K-ras mutations. The data showed that K-ras mutation occurred in 27/87 (31%). The objective response rates and disease control rate in K-ras wild type and mutant patients were 42% (25/60) versus 11% (3/27) (p<0.05) and 60% (36/60) versus 26% (7/27) (p<0.05), respectively. Patients with the wild-type K-ras had significantly higher median survival times and progression-free survival, than patients with mutated K-ras (21 months versus 17 months, p=0.017; 10 months versus 6 months, p=0.6). These findings suggest that a high frequency of K-ras mutations occurs in Chinese mCRC patients and that K-ras mutation is required to select patients for eligibility for cetuximab therapy. Further prospective studies using a large sample size are needed to confirm these preliminary findings. PMID:25950441

  5. Prolactin inhibits a major tumor-suppressive function of wild type BRCA1.

    PubMed

    Chen, Kuan-Hui Ethan; Walker, Ameae M

    2016-06-01

    Even though mutations in the tumor suppressor, BRCA1, markedly increase the risk of breast and ovarian cancer, most breast and ovarian cancers express wild type BRCA1. An important question is therefore how the tumor-suppressive function of normal BRCA1 is overcome during development of most cancers. Because prolactin promotes these and other cancers, we investigated the hypothesis that prolactin interferes with the ability of BRCA1 to inhibit the cell cycle. Examining six different cancer cell lines with wild type BRCA1, and making use of both prolactin and the growth-inhibiting selective prolactin receptor modulator, S179D PRL, we demonstrate that prolactin activation of Stat5 results in the formation of a complex between phospho-Stat5 and BRCA1. Formation of this complex does not interfere with nuclear translocation or binding of BRCA1 to the p21 promoter, but does interfere with the ability of BRCA1 to transactivate the p21 promoter. Overexpression of a dominant-negative Stat5 in prolactin-stimulated cells resulted in increased p21 expression. We conclude that prolactin inhibits a major tumor-suppressive function of BRCA1 by interfering with BRCA1's upregulation of expression of the cell cycle inhibitor, p21. PMID:26970274

  6. Wild-type Cu/Zn superoxide dismutase stabilizes mutant variants by heterodimerization.

    PubMed

    Weichert, Anna; Besemer, Anna S; Liebl, Martina; Hellmann, Nadja; Koziollek-Drechsler, Ingrid; Ip, Philbert; Decker, Heinz; Robertson, Janice; Chakrabartty, Avijit; Behl, Christian; Clement, Albrecht M

    2014-02-01

    Mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1) are responsible for a subset of amyotrophic lateral sclerosis cases presumably by the acquisition of as yet unknown toxic properties. Additional overexpression of wild-type SOD1 in mutant SOD1 transgenic mice did not improve but rather accelerated the disease course. Recently, it was documented that the presence of wild-type SOD1 (SOD(WT)) reduced the aggregation propensity of mutant SOD1 by the formation of heterodimers between mutant and SOD1(WT) and that these heterodimers displayed at least a similar toxicity in cellular and animal models. In this study we investigated the biochemical and biophysical properties of obligate SOD1 dimers that were connected by a peptide linker. Circular dichroism spectra indicate an increased number of unstructured residues in SOD1 mutants. However, SOD1(WT) stabilized the folding of heterodimers compared to mutant homodimers as evidenced by an increase in resistance against proteolytic degradation. Heterodimerization also reduced the affinity of mutant SOD1 to antibodies detecting misfolded SOD1. In addition, the formation of obligate dimers resulted in a detection of substantial dismutase activity even of the relatively labile SOD1(G85R) mutant. These data indicate that soluble, dismutase-active SOD1 dimers might contribute at least partially to mutant SOD1 toxicity. PMID:24200866

  7. Gene Mutation Analysis in EGFR Wild Type NSCLC Responsive to Erlotinib: Are There Features to Guide Patient Selection?

    PubMed Central

    Ulivi, Paola; Delmonte, Angelo; Chiadini, Elisa; Calistri, Daniele; Papi, Maximilian; Mariotti, Marita; Verlicchi, Alberto; Ragazzini, Angela; Capelli, Laura; Gamboni, Alessandro; Puccetti, Maurizio; Dubini, Alessandra; Burgio, Marco Angelo; Casanova, Claudia; Crinò, Lucio; Amadori, Dino; Dazzi, Claudio

    2014-01-01

    Tyrosine kinase inhibitors (TKIs) are very efficacious in non-small-cell lung cancer (NSCLC) patients harboring activating Epidermal Growth Factor Receptor (EGFR) mutations. However, about 10% of EGFR wild type (wt) patients respond to TKI, with unknown molecular mechanisms of sensitivity. We considered a case series of 34 EGFR wt NSCLC patients responsive to erlotinib after at least one line of therapy. Responsive patients were matched with an equal number of non-responsive EGFR wt patients. A panel of 26 genes, for a total of 214 somatic mutations, was analyzed by MassARRAY® System (Sequenom, San Diego, CA, USA). A 15% KRAS mutation was observed in both groups, with a prevalence of G12C in non-responders (80% vs. 40% in responders). NOTCH1, p53 and EGFR-resistance-related mutations were found more frequently in non-responders, whereas EGFR-sensitizing mutations and alterations in genes involved in proliferation pathways were more frequent in responders. In conclusion, our findings indicate that p53, NOTCH1 and exon 20 EGFR mutations seem to be related to TKI resistance. KRAS mutations do not appear to influence the TKI response, although G12C mutation is more frequent in non-responders. Finally, the use of highly sensitive methodologies could lead to the identification of under-represented EGFR mutations potentially associated with TKI sensitivity. PMID:25561229

  8. Purification of extrachloroplastic. beta. -amylase from leaves of starchless and wild type Arabidopsis

    SciTech Connect

    Somerville, C.; Monroe, J.; Preiss, J. )

    1989-04-01

    Amylase activity in crude leaf extracts from starchless mutants of Arabidopsis thaliana is 5 to 10 fold higher than in the wild type (WT) when plants are grown under a 12 h photoperiod. Visualized on native PAGE, the increased activity is attributed primarily to a previously characterized extrachloroplastic {beta}-(exo)amylase. The {beta}-amylases from phosoglucomutase deficient (starchless) and WT leaves were purified to homogeneity in two steps utilizing polyethylene glycol fractionation, and cyclohexaamylose affinity chromatography. The enzyme from both mutant and WT leaves had negligible activity toward either {beta}-limit dextrin or pullulan. The specific activities of both purified enzymes were similar indicating that the protein is over-expressed in the mutant. Preliminary antibody neutralization experiments suggest that the two {beta}-amylases are not different.

  9. Expression of Escherichia coli virulence usher protein attenuates wild-type Salmonella.

    PubMed

    Yang, Xinghong; Suo, Zhiyong; Thornburg, Theresa; Holderness, Kathryn; Cao, Ling; Lim, Timothy; Walters, Nancy; Kellerman, Laura; Loetterle, Linda; Avci, Recep; Pascual, David W

    2012-01-01

    Generation of a live attenuated vaccine for bacterial pathogens often requires prior knowledge of the pathogen's virulence factors. We hypothesized an alternative approach of heterologous gene expression would make a wild-type (wt) pathogen more susceptible to host cell killing, thus, resulting in immunization. As proof of concept, the heterologous expression of enterotoxigenic E. coli (ETEC) colonization factor antigen I (CFA/I) was tested to attenuate Salmonella. The overexpression of CFA/I resulted in significant attenuation of wt Salmonella. In-depth studies revealed the attenuation depended on the co-expression of chaperone (CfaA) and usher (CfaC) proteins. Remarkably, the CfaAC-attenuated Salmonella conferred protection against wt Salmonella challenge. Mechanistic study indicated CfaAC made Salmonella outer membranes permeable, causing Salmonella to be vulnerable to host destruction. Thus, enhancing bacterial permeability via CfaAC represents an alternative method to attenuate pathogens despite the presence of unknown virulence factors. PMID:22286706

  10. KRAS(G12D)-mediated oncogenic transformation of thyroid follicular cells requires long-term TSH stimulation and is regulated by SPRY1.

    PubMed

    Zou, Minjing; Baitei, Essa Y; Al-Rijjal, Roua A; Parhar, Ranjit S; Al-Mohanna, Futwan A; Kimura, Shioko; Pritchard, Catrin; BinEssa, Huda; Alanazi, Azizah A; Alzahrani, Ali S; Akhtar, Mohammed; Assiri, Abdullah M; Meyer, Brian F; Shi, Yufei

    2015-11-01

    KRAS(G12D) can cause lung cancer rapidly, but is not sufficient to induce thyroid cancer. It is not clear whether long-term serum thyroid stimulating hormone (TSH) stimulation can promote KRAS(G12D)-mediated thyroid follicular cell transformation. In the present study, we investigated the effect of long-term TSH stimulation in KRAS(G12D) knock-in mice and the role of Sprouty1 (SPRY1) in KRAS(G12D)-mediated signaling. We used TPO-KRAS(G12D) mice for thyroid-specific expression of KRAS(G12D) under the endogenous KRAS promoter. Twenty TPO-KRAS(G12D) mice were given anti-thyroid drug propylthiouracil (PTU, 0.1% w/v) in drinking water to induce serum TSH and 20 mice were without PTU treatment. Equal number of wild-type littermates (TPO-KRAS(WT)) was given the same treatment. The expression of SPRY1, a negative regulator of receptor tyrosine kinase (RTK) signaling, was analyzed in both KRAS(G12D)-and BRAF(V600E)-induced thyroid cancers. Without PTU treatment, only mild thyroid enlargement and hyperplasia were observed in TPO-KRAS(G12D) mice. With PTU treatment, significant thyroid enlargement and hyperplasia occurred in both TPO-KRAS(G12D) and TPO-KRAS(WT) littermates. Thyroids from TPO-KRAS(G12D) mice were six times larger than TPO-KRAS(WT) littermates. Distinct thyroid histology was found between TPO-KRAS(G12D) and TPO-KRAS(WT) mice: thyroid from TPO-KRAS(G12D) mice showed hyperplasia with well-maintained follicular architecture whereas in TPO-KRAS(WT) mice this structure was replaced by papillary hyperplasia. Among 10 TPO-KRAS(G12D) mice monitored for 14 months, two developed follicular thyroid cancer (FTC), one with pulmonary metastasis. Differential SPRY1 expression was demonstrated: increased in FTC and reduced in papillary thyroid cancer (PTC). The increased SPRY1 expression in FTC promoted TSH-RAS signaling through PI3K/AKT pathway whereas downregulation of SPRY1 by BRAF(V600E) in PTC resulted in both MAPK and PI3K/AKT activation. We conclude that chronic TSH

  11. KRAS as a Therapeutic Target

    PubMed Central

    McCormick, Frank

    2015-01-01

    KRAS proteins play a major role in human cancer, but have not yielded to therapeutic attack. New technologies in drug discovery and insights into signaling pathways that KRAS controls have promoted renewed efforts to develop therapies, either through direct targeting of KRAS itself, new ways of blocking KRAS processing, or by identifying targets that KRAS cancers depend on for survival. While drugs that block the well-established downstream pathways, RAF-MAPK and PI 3 kinase, are being tested in the clinic, new efforts are underway to exploit previously unrecognized vulnerabilities, such as altered metabolic networks, or novel pathways identified through synthetic lethal screens. Furthermore, new ways of suppressing KRAS gene expression and of harnessing the immune system offer further hope that new ways of treating KRAS are finally coming into view. These issues are discussed in this edition of CCR Focus. PMID:25878360

  12. Terpenoid Metabolism in Wild-Type and Transgenic Arabidopsis PlantsW⃞

    PubMed Central

    Aharoni, Asaph; Giri, Ashok P.; Deuerlein, Stephan; Griepink, Frans; de Kogel, Willem-Jan; Verstappen, Francel W. A.; Verhoeven, Harrie A.; Jongsma, Maarten A.; Schwab, Wilfried; Bouwmeester, Harro J.

    2003-01-01

    Volatile components, such as terpenoids, are emitted from aerial parts of plants and play a major role in the interaction between plants and their environment. Analysis of the composition and emission pattern of volatiles in the model plant Arabidopsis showed that a range of volatile components are released, primarily from flowers. Most of the volatiles detected were monoterpenes and sesquiterpenes, which in contrast to other volatiles showed a diurnal emission pattern. The active terpenoid metabolism in wild-type Arabidopsis provoked us to conduct an additional set of experiments in which transgenic Arabidopsis overexpressing two different terpene synthases were generated. Leaves of transgenic plants constitutively expressing a dual linalool/nerolidol synthase in the plastids (FaNES1) produced linalool and its glycosylated and hydroxylated derivatives. The sum of glycosylated components was in some of the transgenic lines up to 40- to 60-fold higher than the sum of the corresponding free alcohols. Surprisingly, we also detected the production and emission of nerolidol, albeit at a low level, suggesting that a small pool of its precursor farnesyl diphosphate is present in the plastids. Transgenic lines with strong transgene expression showed growth retardation, possibly as a result of the depletion of isoprenoid precursors in the plastids. In dual-choice assays with Myzus persicae, the FaNES1-expressing lines significantly repelled the aphids. Overexpression of a typical cytosolic sesquiterpene synthase resulted in the production of only trace amounts of the expected sesquiterpene, suggesting tight control of the cytosolic pool of farnesyl diphosphate, the precursor for sesquiterpenoid biosynthesis. This study further demonstrates the value of Arabidopsis for studies of the biosynthesis and ecological role of terpenoids and provides new insights into their metabolism in wild-type and transgenic plants. PMID:14630967

  13. Impaired olfactory bulb neurogenesis depends on the presence of human wild-type alpha-synuclein.

    PubMed

    May, V E L; Nuber, S; Marxreiter, F; Riess, O; Winner, B; Winkler, J

    2012-10-11

    Synucleinopathies including Parkinson's disease (PD) are characterized by the accumulation of alpha-synuclein (α-syn) within neural cell bodies and their processes. Transgenic mice overexpressing human wild-type or mutant forms of α-syn under the control of different promoters were developed to analyse the underlying neuropathology of PD. One of the earliest clinical symptoms associated with PD is olfactory impairment. The generation of new neurons persists up to adulthood in mammals, in particular the olfactory bulb (OB). In order to assess this process in relation to α-syn accumulation, we used mice overexpressing human wild-type α-syn under the regulatable control (tet-off) of the calcium/calmodulin-dependent protein kinase IIα-promoter (CaMKII). We observed a decrease in OB neurogenesis in transgenic animals compared to controls using 5-bromo-2'-deoxyuridine (BrdU) to label newly generated cells (neuron-specific nuclear protein; NeuN). After cessation of transgene expression we detected an increase in newly generated cells both in granular (GCL) and glomerular (GLOM) layers of the OB. This led to a rescue of newly generated neurons (BrdU(+)/NeuN(+)) within the GLOM with a distinct specificity for the dopaminergic subpopulation. In contrast, we did not detect a cell-specific rescue of neuronal cells in the GCL suggesting diverse effects of alpha-synucleinopathy in both interneuronal layers of the OB. Colabelling of BrdU with glial markers showed that a differentiation into neither astroglia nor microglia attributed to the observed phenotype in the GCL. In particular, BrdU(+) particles located within microglial cells were predominantly associated close to the membrane therefore the resembling phagocytosed nuclear fragments of BrdU(+) cells. Thus, our study further contributes insights into α-syn accumulation as a causative player in the impairment of adult neurogenesis and emphasizes its diverse role in cell renewal of distinct OB cell layers. PMID:22814000

  14. Efficient Genotyping of KRAS Mutant Non-Small Cell Lung Cancer Using a Multiplexed Droplet Digital PCR Approach

    PubMed Central

    Pender, Alexandra; Garcia-Murillas, Isaac; Rana, Sareena; Cutts, Rosalind J.; Kelly, Gavin; Fenwick, Kerry; Kozarewa, Iwanka; Gonzalez de Castro, David; Bhosle, Jaishree; O’Brien, Mary; Turner, Nicholas C.; Popat, Sanjay; Downward, Julian

    2015-01-01

    Droplet digital PCR (ddPCR) can be used to detect low frequency mutations in oncogene-driven lung cancer. The range of KRAS point mutations observed in NSCLC necessitates a multiplex approach to efficient mutation detection in circulating DNA. Here we report the design and optimisation of three discriminatory ddPCR multiplex assays investigating nine different KRAS mutations using PrimePCR™ ddPCR™ Mutation Assays and the Bio-Rad QX100 system. Together these mutations account for 95% of the nucleotide changes found in KRAS in human cancer. Multiplex reactions were optimised on genomic DNA extracted from KRAS mutant cell lines and tested on DNA extracted from fixed tumour tissue from a cohort of lung cancer patients without prior knowledge of the specific KRAS genotype. The multiplex ddPCR assays had a limit of detection of better than 1 mutant KRAS molecule in 2,000 wild-type KRAS molecules, which compared favourably with a limit of detection of 1 in 50 for next generation sequencing and 1 in 10 for Sanger sequencing. Multiplex ddPCR assays thus provide a highly efficient methodology to identify KRAS mutations in lung adenocarcinoma. PMID:26413866

  15. Efficient Genotyping of KRAS Mutant Non-Small Cell Lung Cancer Using a Multiplexed Droplet Digital PCR Approach.

    PubMed

    Pender, Alexandra; Garcia-Murillas, Isaac; Rana, Sareena; Cutts, Rosalind J; Kelly, Gavin; Fenwick, Kerry; Kozarewa, Iwanka; Gonzalez de Castro, David; Bhosle, Jaishree; O'Brien, Mary; Turner, Nicholas C; Popat, Sanjay; Downward, Julian

    2015-01-01

    Droplet digital PCR (ddPCR) can be used to detect low frequency mutations in oncogene-driven lung cancer. The range of KRAS point mutations observed in NSCLC necessitates a multiplex approach to efficient mutation detection in circulating DNA. Here we report the design and optimisation of three discriminatory ddPCR multiplex assays investigating nine different KRAS mutations using PrimePCR™ ddPCR™ Mutation Assays and the Bio-Rad QX100 system. Together these mutations account for 95% of the nucleotide changes found in KRAS in human cancer. Multiplex reactions were optimised on genomic DNA extracted from KRAS mutant cell lines and tested on DNA extracted from fixed tumour tissue from a cohort of lung cancer patients without prior knowledge of the specific KRAS genotype. The multiplex ddPCR assays had a limit of detection of better than 1 mutant KRAS molecule in 2,000 wild-type KRAS molecules, which compared favourably with a limit of detection of 1 in 50 for next generation sequencing and 1 in 10 for Sanger sequencing. Multiplex ddPCR assays thus provide a highly efficient methodology to identify KRAS mutations in lung adenocarcinoma. PMID:26413866

  16. Porphyrin Interactions with Wild Type and Mutant Mouse Ferrochelatase

    SciTech Connect

    Ferreira, Gloria C.; Franco, Ricardo; Lu, Yi; Ma, Jian-Guo; Shelnutt, John A.

    1999-05-19

    Ferrochelatase (EC 4.99.1.1), the terminal enzyme of the heme biosynthetic pathway, catalyzes Fe2+ chelation into protoporphyrin IX. Resonance Raman and W-visible absorbance spectroscopes of wild type and engineered variants of murine ferrochelatase were used to examine the proposed structural mechanism for iron insertion into protoporphyrin by ferrochelatase. The recombinant variants (i.e., H207N and E287Q) are enzymes in which the conserved amino acids histidine-207 and glutamate-287 of murine ferrochelatase were substituted with asparagine and glutamine, respectively. Both of these residues are at the active site of the enzyme as deduced from the Bacillus subtilis ferrochelatase three-dimensional structure. Addition of free base or metalated porphyrins to wild type ferrochelatase and H207N variant yields a quasi 1:1 complex, possibly a monomeric protein-bound species. In contrast, the addition of porphyrin (either free base or metalated) to E287Q is sub-stoichiometric, as this variant retains bound porphyrin in the active site during isolation and purification. The specificity of porphyrin binding is confirmed by the narrowing of the structure-sensitive resonance Raman lines and the vinyl vibrational mode. Resonance Raman spectra of free base and metalated porphyrins bound to the wild type ferrochelatase indicate a nonplanar distortion of the porphyrin macrocycle, although the magnitude of the distortion cannot be determined without first defining the specific type of deformation. Significantly, the extent of the nonplanar distortion varies in the case of H207N- and E287Q-bound porphyrins. In fact, resonance Raman spectral decomposition indicates a homogeneous ruffled distortion for the nickel protoporphyrin bound to the wild type ferrochelatase, whereas both a planar and ruffled conformations are present for the H207N-bound porphyrin. Perhaps more revealing is the unusual resonance , 3 Raman spectrum of the endogenous E287Q-bound porphyrin, which has

  17. Oncogenic KRAS Impairs EGFR Antibodies' Efficiency by C/EBPβ-Dependent Suppression of EGFR Expression12

    PubMed Central

    Derer, Stefanie; Berger, Sven; Schlaeth, Martin; Schneider-Merck, Tanja; Klausz, Katja; Lohse, Stefan; Overdijk, Marije B; Dechant, Michael; Kellner, Christian; Nagelmeier, Iris; Scheel, Andreas H; Lammerts van Bueren, Jeroen J; van de Winkel, Jan GJ; Parren, Paul WHI; Peipp, Matthias; Valerius, Thomas

    2012-01-01

    Oncogenic KRAS mutations in colorectal cancer (CRC) are associated with lack of benefit from epidermal growth factor receptor (EGFR)-directed antibody (Ab) therapy. However, the mechanisms by which constitutively activated KRAS (KRASG12V) impairs effector mechanisms of EGFR-Abs are incompletely understood. Here, we established isogenic cell line models to systematically investigate the impact of KRASG12V on tumor growth in mouse A431 xenograft models as well as on various modes of action triggered by EGFR-Abs in vitro. KRASG12V impaired EGFR-Ab-mediated growth inhibition by stimulating receptor-independent downstream signaling. KRASG12V also rendered tumor cells less responsive to Fc-mediated effector mechanisms of EGFR-Abs—such as complement-dependent cytotoxicity (CDC) and Ab-dependent cell-mediated cytotoxicity (ADCC). Impaired CDC and ADCC activities could be linked to reduced EGFR expression in KRAS-mutated versus wild-type (wt) cells, which was restored by small interfering RNA (siRNA)-mediated knockdown of KRAS4b. Immunohistochemistry experiments also revealed lower EGFR expression in KRAS-mutated versus KRAS-wt harboring CRC samples. Analyses of potential mechanisms by which KRASG12V downregulated EGFR expression demonstrated significantly decreased activity of six distinct transcription factors. Additional experiments suggested the CCAAT/enhancer-binding protein (C/EBP) family to be implicated in the regulation of EGFR promoter activity in KRAS-mutated tumor cells by suppressing EGFR transcription through up-regulation of the inhibitory family member C/EBPβ-LIP. Thus, siRNA-mediated knockdown of C/EBPβ led to enhanced EGFR expression and Ab-mediated cytotoxicity against KRAS-mutated cells. Together, these results demonstrate that KRASG12V signaling induced C/EBPβ-dependent suppression of EGFR expression, thereby impairing Fc-mediated effector mechanisms of EGFR-Abs and rendering KRAS-mutated tumor cells less sensitive to these therapeutic agents. PMID

  18. Cis-acting elements in its 3' UTR mediate post-transcriptional regulation of KRAS.

    PubMed

    Kim, Minlee; Kogan, Nicole; Slack, Frank J

    2016-03-15

    Multiple RNA-binding proteins and non-coding RNAs, such as microRNAs (miRNAs), are involved in post-transcriptional gene regulation through recognition motifs in the 3' untranslated region (UTR) of their target genes. The KRAS gene encodes a key signaling protein, and its messenger RNA (mRNA) contains an exceptionally long 3' UTR; this suggests that it may be subject to a highly complex set of regulatory processes. However, 3' UTR-dependent regulation of KRAS expression has not been explored in detail. Using extensive deletion and mutational analyses combined with luciferase reporter assays, we have identified inhibitory and stabilizing cis-acting regions within the KRAS 3' UTR that may interact with miRNAs and RNA-binding proteins, such as HuR. Particularly, we have identified an AU-rich 49-nt fragment in the KRAS 3' UTR that is required for KRAS 3' UTR reporter repression. This element contains a miR-185 complementary element, and we show that overexpression of miR-185 represses endogenous KRAS mRNA and protein in vitro. In addition, we have identified another 49-nt fragment that is required to promote KRAS 3' UTR reporter expression. These findings indicate that multiple cis-regulatory motifs in the 3' UTR of KRAS finely modulate its expression, and sequence alterations within a binding motif may disrupt the precise functions of trans-regulatory factors, potentially leading to aberrant KRAS expression. PMID:26930719

  19. TP53 and Let-7a micro-RNA Regulate K-Ras Activity in HCT116 Colorectal Cancer Cells

    PubMed Central

    Luu, Carrie; Heinrich, Eileen L.; Duldulao, Marjun; Arrington, Amanda K.; Fakih, Marwan; Garcia-Aguilar, Julio; Kim, Joseph

    2013-01-01

    Recent reports have indicated that KRAS and TP53 mutations predict response to therapy in colorectal cancer. However, little is known about the relationship between these two common genetic alterations. Micro-RNAs (miRNAs), a class of noncoding RNA implicated in cellular processes, have been increasingly linked to KRAS and TP53. We hypothesized that lethal-7a (let-7a) miRNA regulates KRAS through TP53. To investigate the relationship between KRAS, TP53, and let-7a, we used HCT116 KRASmut human colorectal cancer cells with four different genotypic modifications in TP53 (TP53−/−, TP53+/−, TP53mut/+, and TP53mut/−). Using these cells we observed that K-Ras activity was higher in cells with mutant or knocked out TP53 alleles, suggesting that wild-type TP53 may suppress K-Ras activity. Let-7a was present in HCT116 KRASmut cells, though there was no correlation between let-7a level and TP53 genotype status. To explore how let-7a may regulate K-Ras in the different TP53 genotype cells we used let-7a inhibitor and demonstrated increased K-Ras activity across all TP53, thus corroborating prior reports that let-7a regulates K-Ras. To assess potential clinical implications of this regulatory network, we examined the influence of TP53 genotype and let-7a inhibition on colon cancer cell survival following chemoradiation therapy (CRT). We observed that cells with complete loss of wild-type TP53 alleles (−/− or −/mut) were resistant to CRT following treatment with 5-fluorouracil and radiation. Further increase in K-Ras activity with let-7a inhibition did not impact survival in these cells. In contrast, cells with single or double wild-type TP53 alleles were moderately responsive to CRT and exhibited resistance when let-7a was inhibited. In summary, our results show a complex regulatory system involving TP53, KRAS, and let-7a. Our results may provide clues to understand and target these interactions in colorectal cancer. PMID:23936455

  20. KRAS (but not BRAF) mutations in ovarian serous borderline tumor are associated with recurrent low-grade serous carcinoma

    PubMed Central

    Tsang, Yvonne T.; Deavers, Michael T.; Sun, Charlotte C.; Kwan, Suet-Yan; Kuo, Eric; Malpica, Anais; Mok, Samuel C.; Gershenson, David M.; Wong, Kwong-Kwok

    2014-01-01

    BRAF and KRAS mutations in ovarian serous borderline tumors (OSBTs) and ovarian low-grade serous carcinomas (LGSCs) have been previously described. However, whether those OSBTs would progress to LGSCs or those LGSCs were developed from OSBT precursors in previous studies is unknown. Therefore, we assessed KRAS and BRAF mutations in tumor samples from 23 recurrent LGSC patients with known initial diagnosis of OSBT. Paraffin blocks from both OSBT and LGSC samples were available for 5 patients, and either OSBT or LGSC were available for another 18 patients. Tumor cells from paraffin-embedded tissues were dissected out for mutation analysis by conventional polymerase chain reaction (PCR) and Sanger sequencing. Tumors that appeared to have wild-type KRAS by conventional PCR–Sanger sequencing were further analyzed by full COLD (coamplification at lower denaturation temperature)-PCR and deep sequencing. Full COLD-PCR was able to enrich the amplification of mutated alleles. Deep sequencing was performed with the Ion Torrent personal genome machine (PGM). By conventional PCR–Sanger sequencing, BRAF mutation was detected only in one patient and KRAS mutations were detected in 10 patients. Full COLD-PCR deep sequencing detected low-abundance KRAS mutations in eight additional patients. Three of the five patients with both OSBT and LGSC samples available had the same KRAS mutations detected in both OSBT and LGSC samples. The remaining two patients had only KRAS mutations detected in their LGSC samples. For patients with either OSBT or LGSC samples available, KRAS mutations were detected in 7 OSBT samples and 6 LGSC samples. To our surprise, patients with the KRAS G12V mutation appeared to have shorter survival times. In summary, KRAS mutations are very common in recurrent LGSC, while BRAF mutations are rare. The findings indicate that recurrent LGSC can arise from proliferation of OSBT tumor cells with or without detectable KRAS mutations. PMID:24549645

  1. Vitamin C selectively kills KRAS and BRAF mutant colorectal cancer cells by targeting GAPDH.

    PubMed

    Yun, Jihye; Mullarky, Edouard; Lu, Changyuan; Bosch, Kaitlyn N; Kavalier, Adam; Rivera, Keith; Roper, Jatin; Chio, Iok In Christine; Giannopoulou, Eugenia G; Rago, Carlo; Muley, Ashlesha; Asara, John M; Paik, Jihye; Elemento, Olivier; Chen, Zhengming; Pappin, Darryl J; Dow, Lukas E; Papadopoulos, Nickolas; Gross, Steven S; Cantley, Lewis C

    2015-12-11

    More than half of human colorectal cancers (CRCs) carry either KRAS or BRAF mutations and are often refractory to approved targeted therapies. We found that cultured human CRC cells harboring KRAS or BRAF mutations are selectively killed when exposed to high levels of vitamin C. This effect is due to increased uptake of the oxidized form of vitamin C, dehydroascorbate (DHA), via the GLUT1 glucose transporter. Increased DHA uptake causes oxidative stress as intracellular DHA is reduced to vitamin C, depleting glutathione. Thus, reactive oxygen species accumulate and inactivate glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Inhibition of GAPDH in highly glycolytic KRAS or BRAF mutant cells leads to an energetic crisis and cell death not seen in KRAS and BRAF wild-type cells. High-dose vitamin C impairs tumor growth in Apc/Kras(G12D) mutant mice. These results provide a mechanistic rationale for exploring the therapeutic use of vitamin C for CRCs with KRAS or BRAF mutations. PMID:26541605

  2. miR-143 or miR-145 overexpression increases cetuximab-mediated antibody-dependent cellular cytotoxicity in human colon cancer cells

    PubMed Central

    Gomes, Sofia E.; Simões, André E. S.; Pereira, Diane M.; Castro, Rui E.; Rodrigues, Cecília M. P.; Borralho, Pedro M.

    2016-01-01

    miR-143 and miR-145 are downregulated in colon cancer. Here, we tested the effect of restoring these miRNAs on sensitization to cetuximab in mutant KRAS (HCT116 and SW480) and wild-type KRAS (SW48) colon cancer cells. We evaluated cetuximab-mediated antibody-dependent cellular cytotoxicity (ADCC) and the modulation of signaling pathways involved in immune effector cell-mediated elimination of cancer cells. Stable miR-143 or miR-145 overexpression increased cell sensitivity to cetuximab, resulting in a significant increase of cetuximab-mediated ADCC independently of KRAS status. Importantly, HCT116 cells overexpressing these miRNAs triggered apoptosis in result of cetuximab-mediated ADCC, effected by peripheral blood mononuclear cells (p < 0.01). This was associated with increased apoptosis and caspase-3/7 activity, and reduced Bcl-2 protein expression (p < 0.01). In addition, caspase inhibition abrogated cetuximab-mediated ADCC in HCT116 cells overexpressing either miR-143 or miR-145 (p < 0.01). Furthermore, Bcl-2 silencing led to high level of cetuximab-mediated ADCC, compared to control siRNA (p < 0.05). Importantly, granzyme B inhibition, abrogated cetuximab-mediated ADCC, reducing caspase-3/7 activity (p < 0.01). Collectively, our data suggests that re-introduction of miR-143 or miR-145 may provide a new approach for development of therapeutic strategies to re-sensitize colon cancer cells to cetuximab by stimulating cetuximab-dependent ADCC to induce cell death. PMID:26824186

  3. Characterization of a novel oncogenic K-ras mutation in colon cancer

    SciTech Connect

    Akagi, Kiwamu . E-mail: akagi@cancer-c.pref.saitama.jp; Uchibori, Ryosuke; Yamaguchi, Kensei; Kurosawa, Keiko; Tanaka, Yoichiro; Kozu, Tomoko

    2007-01-19

    Activating mutations of RAS are frequently observed in subsets of human cancers, indicating that RAS activation is involved in tumorigenesis. Here, we identified and characterized a novel G to T transversion mutation of the K-ras gene at the third position of codon 19 (TTG) which substituted phenylalanine for leucine in 3 primary colon carcinomas. Biological and biochemical activity was examined using transformed NIH3T3 cells expressing mutant or wild-type K-ras. Transformants harboring the K-ras mutation at codon 19 showed proliferative capacity under serum-starved conditions, less contact inhibition, anchorage-independent growth, tumorigenicity in nude mice and elevation of active Ras-GTP levels. These results indicated that this novel mutation possesses high oncogenic activity.

  4. KRAS G12V Mutation Detection by Droplet Digital PCR in Circulating Cell-Free DNA of Colorectal Cancer Patients.

    PubMed

    Olmedillas López, Susana; García-Olmo, Dolores C; García-Arranz, Mariano; Guadalajara, Héctor; Pastor, Carlos; García-Olmo, Damián

    2016-01-01

    KRAS mutations are responsible for resistance to anti-epidermal growth factor receptor (EGFR) therapy in colorectal cancer patients. These mutations sometimes appear once treatment has started. Detection of KRAS mutations in circulating cell-free DNA in plasma ("liquid biopsy") by droplet digital PCR (ddPCR) has emerged as a very sensitive and promising alternative to serial biopsies for disease monitoring. In this study, KRAS G12V mutation was analyzed by ddPCR in plasma DNA from 10 colorectal cancer patients and compared to six healthy donors. The percentage of KRAS G12V mutation relative to wild-type sequences in tumor-derived DNA was also determined. KRAS G12V mutation circulating in plasma was detected in 9 of 10 colorectal cancer patients whose tumors were also mutated. Colorectal cancer patients had 35.62 copies of mutated KRAS/mL plasma, whereas in healthy controls only residual copies were found (0.62 copies/mL, p = 0.0066). Interestingly, patients with metastatic disease showed a significantly higher number of mutant copies than M0 patients (126.25 versus 9.37 copies/mL, p = 0.0286). Wild-type KRAS was also significantly elevated in colorectal cancer patients compared to healthy controls (7718.8 versus 481.25 copies/mL, p = 0.0002). In conclusion, KRAS G12V mutation is detectable in plasma of colorectal cancer patients by ddPCR and could be used as a non-invasive biomarker. PMID:27043547

  5. KRAS G12V Mutation Detection by Droplet Digital PCR in Circulating Cell-Free DNA of Colorectal Cancer Patients

    PubMed Central

    Olmedillas López, Susana; García-Olmo, Dolores C.; García-Arranz, Mariano; Guadalajara, Héctor; Pastor, Carlos; García-Olmo, Damián

    2016-01-01

    KRAS mutations are responsible for resistance to anti-epidermal growth factor receptor (EGFR) therapy in colorectal cancer patients. These mutations sometimes appear once treatment has started. Detection of KRAS mutations in circulating cell-free DNA in plasma (“liquid biopsy”) by droplet digital PCR (ddPCR) has emerged as a very sensitive and promising alternative to serial biopsies for disease monitoring. In this study, KRAS G12V mutation was analyzed by ddPCR in plasma DNA from 10 colorectal cancer patients and compared to six healthy donors. The percentage of KRAS G12V mutation relative to wild-type sequences in tumor-derived DNA was also determined. KRAS G12V mutation circulating in plasma was detected in 9 of 10 colorectal cancer patients whose tumors were also mutated. Colorectal cancer patients had 35.62 copies of mutated KRAS/mL plasma, whereas in healthy controls only residual copies were found (0.62 copies/mL, p = 0.0066). Interestingly, patients with metastatic disease showed a significantly higher number of mutant copies than M0 patients (126.25 versus 9.37 copies/mL, p = 0.0286). Wild-type KRAS was also significantly elevated in colorectal cancer patients compared to healthy controls (7718.8 versus 481.25 copies/mL, p = 0.0002). In conclusion, KRAS G12V mutation is detectable in plasma of colorectal cancer patients by ddPCR and could be used as a non-invasive biomarker. PMID:27043547

  6. Survival outcome according to KRAS mutation status in newly diagnosed patients with stage IV non-small cell lung cancer treated with platinum doublet chemotherapy

    PubMed Central

    Brady, Anna K.; McNeill, Jonathan D.; Judy, Brendan; Bauml, Joshua; Evans, Tracey L.; Cohen, Roger B.; Langer, Corey; Vachani, Anil; Aggarwal, Charu

    2015-01-01

    Introduction Mutations (MT) of the KRAS gene are the most common mutation in non-small cell lung cancer (NSCLC), seen in about 20–25% of all adenocarcinomas. Effect of KRAS MT on response to cytotoxic chemotherapy is unclear. Methods We undertook a single-institution retrospective analysis of 93 consecutive patients with stage IV NSCLC adenocarcinoma with known KRAS and EGFR MT status to determine the association of KRAS MT with survival. All patients were treated between January 1, 2008 and December 31, 2011 with standard platinum based chemotherapy at the University of Pennsylvania. Overall and progression free survival were analyzed using Kaplan-Meier and Cox proportional hazard methods. Results All patients in this series received platinum doublet chemotherapy, and 42 (45%) received bevacizumab. Overall survival and progression free survival for patients with KRAS MT was no worse than for patients with wild type KRAS. Median overall survival for patients with KRAS MT was 19 months (mo) vs. 15.6 mo for KRAS WT, p = 0.34, and progression-free survival was 6.2 mo in patients with KRAS MT vs. 7mo in patients with KRAS WT, p = 0.51. In multivariable analysis including age, race, gender, and ECOG PS, KRAS MT was not associated with overall survival (HR 1.12, 95% CI 0.58–2.16, p = 0.74) or progression free survival (HR 0.80, 95% CI 0.48–1.34, p = 41). Of note, receipt of bevacizumab was associated with improved overall survival only in KRAS WT patients (HR 0.34, p = 0.01). Conclusions KRAS MT are not associated with inferior progression-free and overall survival in advanced NSCLC patients treated with standard first-line platinum-based chemotherapy. PMID:26471290

  7. Comparative transcriptomic analysis of silkwormBmovo-1 and wild type silkworm ovary

    PubMed Central

    Xue, Renyu; Hu, Xiaolong; Zhu, Liyuan; Cao, Guangli; Huang, Moli; Xue, Gaoxu; Song, Zuowei; Lu, Jiayu; Chen, Xueying; Gong, Chengliang

    2015-01-01

    The detailed molecular mechanism of Bmovo-1 regulation of ovary size is unclear. To uncover the mechanism of Bmovo-1 regulation of ovarian development and oogenesis using RNA-Seq, we compared the transcriptomes of wild type (WT) and Bmovo-1-overexpressing silkworm (silkworm+Bmovo-1) ovaries. Using a pair-end Illumina Solexa sequencing strategy, 5,296,942 total reads were obtained from silkworm+Bmovo-1 ovaries and 6,306,078 from WT ovaries. The average read length was about 100 bp. Clean read ratios were 98.79% for silkworm+Bmovo-1 and 98.87% for WT silkworm ovaries. Comparative transcriptome analysis showed 123 upregulated and 111 downregulated genes in silkworm+Bmovo-1 ovaries. These differentially expressed genes were enriched in the extracellular and extracellular spaces and involved in metabolism, genetic information processing, environmental information processing, cellular processes and organismal systems. Bmovo-1 overexpression in silkworm ovaries might promote anabolism for ovarian development and oogenesis and oocyte proliferation and transport of nutrients to ovaries by altering nutrient partitioning, which would support ovary development. Excessive consumption of nutrients for ovary development alters nutrient partitioning and deters silk protein synthesis. PMID:26643037

  8. Wild type p53 reactivation: from lab bench to clinic.

    PubMed

    Selivanova, Galina

    2014-08-19

    The p53 tumor suppressor is the most frequently inactivated gene in cancer. Several mouse models have demonstrated that the reconstitution of the p53 function suppresses the growth of established tumors. These facts, taken together, promote the idea of p53 reactivation as a strategy to combat cancer. This review will focus on recent advances in the development of small molecules which restore the function of wild type p53 by blocking its inhibitors Mdm2 and MdmX or their upstream regulators and discuss the impact of different p53 functions for tumor prevention and tumor eradication. Finally, the recent progress in p53 research will be analyzed concerning the role of p53 cofactors and cellular environment in the biological response upon p53 reactivation and how this can be applied in clinic. PMID:24726725

  9. Coexpression of wild-type and variant oestrogen receptor mRNAs in a panel of human breast cancer cell lines.

    PubMed Central

    Castles, C. G.; Klotz, D. M.; Fuqua, S. A.; Hill, S. M.

    1995-01-01

    Wild-type as well as variant oestrogen receptor (ER) mRNAs with exon 5 and 7 deleted were identified in a panel of human breast tumour cell lines by reverse transcriptase-polymerase chain reaction followed by dideoxynucleotide sequence analysis, and then quantitated by ribonuclease protection analysis. All cell lines categorised as ER+ by ligand-binding analysis expressed both wild-type and variant ER transcripts. Most cell lines classified as ER- did not express any ER transcript. However, three ER- cell lines (BT-20, MDA-MB-330 and T47Dco) expressed both wild-type and variant transcripts. A differential pattern of expression of wild type to variant was seen in both ER+ and ER- cell lines, however this pattern was not paralleled by differences in ligand-binding activity. Breast tumour cell lines previously classified as ER- expressed significantly lower levels of ER transcripts than did their ER+ counterparts. In view of these findings, as well as earlier reports that the exon 5 deletion ER variant encodes a dominant-positive receptor, it seems clear that some cell lines are misclassified as ER-, and express both wild-type and variant ER mRNAs, and that the overexpression of this variant may account, in part, for their oestrogen-independent phenotype. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:7734323

  10. KRAS mutations: variable incidences in a Brazilian cohort of 8,234 metastatic colorectal cancer patients

    PubMed Central

    2014-01-01

    Background KRAS mutations are frequently found in colorectal cancer (CRC) indicating the importance of its genotyping in the study of the molecular mechanisms behind this disease. Although major advances have occurred over the past decade, there are still important gaps in our understanding of CRC carcinogenesis, particularly whether sex-linked factors play any role. Methods The profile of KRAS mutations in the Brazilian population was analyzed by conducting direct sequencing of KRAS codons 12 and 13 belonging to 8,234 metastatic CRC patient samples. DNA was extracted from paraffin-embedded tissue, exon 1 was amplified by PCR and submitted to direct sequencing. The data obtained was analysed comparing different geographical regions, gender and age. Results The median age was 59 years and the overall percentage of wild-type and mutated KRAS was 62.8% and 31.9%, respectively. Interestingly, different percentages of mutated KRAS patients were observed between male and female patients (32.5% versus 34.8%, respectively; p = 0.03). KRAS Gly12Asp mutation was the most prevalent for both genders and for most regions, with the exception of the North where Gly12Val was the most frequent mutation found. Conclusions To the best of our knowledge this is one of the largest cohorts of KRAS genotyping in CRC patients and the largest to indicate a higher incidence of KRAS mutation in females compared to males in Brazil. Nevertheless, further research is required to better address the impact of gender differences in colorectal cancer. PMID:24720724

  11. 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

  12. An extra copy of p53 suppresses development of spontaneous Kras-driven but not radiation-induced cancer

    PubMed Central

    Moding, Everett J.; Min, Hooney D.; Castle, Katherine D.; Ali, Moiez; Woodlief, Loretta; Williams, Nerissa; Ma, Yan; Kim, Yongbaek; Lee, Chang-Lung; Kirsch, David G.

    2016-01-01

    The tumor suppressor p53 blocks tumor progression in multiple tumor types. Radiation-induced cancer following exposure to radiation therapy or space travel may also be regulated by p53 because p53 has been proposed to respond to DNA damage to suppress tumorigenesis. Here, we investigate the role of p53 in lung carcinogenesis and lymphomagenesis in LA-1 KrasG12D mice with wild-type p53 or an extra copy of p53 (super p53) exposed to fractionated total body irradiation with low linear energy transfer (low-LET) X-rays or high-LET iron ions and compared tumor formation in these mice with unirradiated controls. We found that an additional copy of p53 suppressed both Kras-driven lung tumor and lymphoma development in the absence of radiation. However, an additional copy of p53 did not affect lymphoma development following low- or high-LET radiation exposure and was unable to suppress radiation-induced expansion of thymocytes with mutated Kras. Moreover, radiation exposure increased lung tumor size in super p53 but not wild-type p53 mice. These results demonstrate that although p53 suppresses the development of spontaneous tumors expressing KrasG12D, in the context of exposure to ionizing radiation, an extra copy of p53 does not protect against radiation-induced lymphoma and may promote KrasG12D mutant lung cancer. PMID:27453951

  13. Hybridization-Induced Aggregation Technology for Practical Clinical Testing: KRAS Mutation Detection in Lung and Colorectal Tumors.

    PubMed

    Sloane, Hillary S; Landers, James P; Kelly, Kimberly A

    2016-07-01

    KRAS mutations have emerged as powerful predictors of response to targeted therapies in the treatment of lung and colorectal cancers; thus, prospective KRAS genotyping is essential for appropriate treatment stratification. Conventional mutation testing technologies are not ideal for routine clinical screening, as they often involve complex, time-consuming processes and/or costly instrumentation. In response, we recently introduced a unique analytical strategy for revealing KRAS mutations, based on the allele-specific hybridization-induced aggregation (HIA) of oligonucleotide probe-conjugated microbeads. Using simple, inexpensive instrumentation, this approach allows for the detection of any common KRAS mutation in <10 minutes after PCR. Here, we evaluate the clinical utility of the HIA method for mutation detection (HIAMD). In the analysis of 20 lung and colon tumor pathology specimens, we observed a 100% correlation between the KRAS mutation statuses determined by HIAMD and sequencing. In addition, we were able to detect KRAS mutations in a background of 75% wild-type DNA-a finding consistent with that reported for sequencing. With this, we show that HIAMD allows for the rapid and cost-effective detection of KRAS mutations, without compromising analytical performance. These results indicate the validity of HIAMD as a mutation-testing technology suitable for practical clinical testing. Further expansion of this platform may involve the detection of mutations in other key oncogenic pathways. PMID:27289420

  14. KRAS Genotype Correlates with Proteasome Inhibitor Ixazomib Activity in Preclinical In Vivo Models of Colon and Non-Small Cell Lung Cancer: Potential Role of Tumor Metabolism

    PubMed Central

    Chattopadhyay, Nibedita; Berger, Allison J.; Koenig, Erik; Bannerman, Bret; Garnsey, James; Bernard, Hugues; Hales, Paul; Maldonado Lopez, Angel; Yang, Yu; Donelan, Jill; Jordan, Kristen; Tirrell, Stephen; Stringer, Bradley; Xia, Cindy; Hather, Greg; Galvin, Katherine; Manfredi, Mark; Rhodes, Nelson; Amidon, Ben

    2015-01-01

    In non-clinical studies, the proteasome inhibitor ixazomib inhibits cell growth in a broad panel of solid tumor cell lines in vitro. In contrast, antitumor activity in xenograft tumors is model-dependent, with some solid tumors showing no response to ixazomib. In this study we examined factors responsible for ixazomib sensitivity or resistance using mouse xenograft models. A survey of 14 non-small cell lung cancer (NSCLC) and 6 colon xenografts showed a striking relationship between ixazomib activity and KRAS genotype; tumors with wild-type (WT) KRAS were more sensitive to ixazomib than tumors harboring KRAS activating mutations. To confirm the association between KRAS genotype and ixazomib sensitivity, we used SW48 isogenic colon cancer cell lines. Either KRAS-G13D or KRAS-G12V mutations were introduced into KRAS-WT SW48 cells to generate cells that stably express activated KRAS. SW48 KRAS WT tumors, but neither SW48-KRAS-G13D tumors nor SW48-KRAS-G12V tumors, were sensitive to ixazomib in vivo. Since activated KRAS is known to be associated with metabolic reprogramming, we compared metabolite profiling of SW48-WT and SW48-KRAS-G13D tumors treated with or without ixazomib. Prior to treatment there were significant metabolic differences between SW48 WT and SW48-KRAS-G13D tumors, reflecting higher oxidative stress and glucose utilization in the KRAS-G13D tumors. Ixazomib treatment resulted in significant metabolic regulation, and some of these changes were specific to KRAS WT tumors. Depletion of free amino acid pools and activation of GCN2-eIF2α-pathways were observed both in tumor types. However, changes in lipid beta oxidation were observed in only the KRAS WT tumors. The non-clinical data presented here show a correlation between KRAS genotype and ixazomib sensitivity in NSCLC and colon xenografts and provide new evidence of regulation of key metabolic pathways by proteasome inhibition. PMID:26709701

  15. KRAS Genotype Correlates with Proteasome Inhibitor Ixazomib Activity in Preclinical In Vivo Models of Colon and Non-Small Cell Lung Cancer: Potential Role of Tumor Metabolism.

    PubMed

    Chattopadhyay, Nibedita; Berger, Allison J; Koenig, Erik; Bannerman, Bret; Garnsey, James; Bernard, Hugues; Hales, Paul; Maldonado Lopez, Angel; Yang, Yu; Donelan, Jill; Jordan, Kristen; Tirrell, Stephen; Stringer, Bradley; Xia, Cindy; Hather, Greg; Galvin, Katherine; Manfredi, Mark; Rhodes, Nelson; Amidon, Ben

    2015-01-01

    In non-clinical studies, the proteasome inhibitor ixazomib inhibits cell growth in a broad panel of solid tumor cell lines in vitro. In contrast, antitumor activity in xenograft tumors is model-dependent, with some solid tumors showing no response to ixazomib. In this study we examined factors responsible for ixazomib sensitivity or resistance using mouse xenograft models. A survey of 14 non-small cell lung cancer (NSCLC) and 6 colon xenografts showed a striking relationship between ixazomib activity and KRAS genotype; tumors with wild-type (WT) KRAS were more sensitive to ixazomib than tumors harboring KRAS activating mutations. To confirm the association between KRAS genotype and ixazomib sensitivity, we used SW48 isogenic colon cancer cell lines. Either KRAS-G13D or KRAS-G12V mutations were introduced into KRAS-WT SW48 cells to generate cells that stably express activated KRAS. SW48 KRAS WT tumors, but neither SW48-KRAS-G13D tumors nor SW48-KRAS-G12V tumors, were sensitive to ixazomib in vivo. Since activated KRAS is known to be associated with metabolic reprogramming, we compared metabolite profiling of SW48-WT and SW48-KRAS-G13D tumors treated with or without ixazomib. Prior to treatment there were significant metabolic differences between SW48 WT and SW48-KRAS-G13D tumors, reflecting higher oxidative stress and glucose utilization in the KRAS-G13D tumors. Ixazomib treatment resulted in significant metabolic regulation, and some of these changes were specific to KRAS WT tumors. Depletion of free amino acid pools and activation of GCN2-eIF2α-pathways were observed both in tumor types. However, changes in lipid beta oxidation were observed in only the KRAS WT tumors. The non-clinical data presented here show a correlation between KRAS genotype and ixazomib sensitivity in NSCLC and colon xenografts and provide new evidence of regulation of key metabolic pathways by proteasome inhibition. PMID:26709701

  16. Endocytic Trafficking Routes of Wild Type and ΔF508 Cystic Fibrosis Transmembrane Conductance RegulatorD⃞

    PubMed Central

    Gentzsch, Martina; Chang, Xiu-Bao; Cui, Liying; Wu, Yufeng; Ozols, Victor V.; Choudhury, Amit; Pagano, Richard E.; Riordan, John R.

    2004-01-01

    Intracellular trafficking of cystic fibrosis transmembrane conductance regulator (CFTR) is a focus of attention because it is defective in most patients with cystic fibrosis. ΔF508 CFTR, which does not mature conformationally, normally does not exit the endoplasmic reticulum, but if induced to do so at reduced temperature is short-lived at the surface. We used external epitope-tagged constructs to elucidate the itinerary and kinetics of wild type and ΔF508 CFTR in the endocytic pathway and visualized movement of CFTR from the surface to intracellular compartments. Modulation of different endocytic steps with low temperature (16°C) block, protease inhibitors, and overexpression of wild type and mutant Rab GTPases revealed that surface CFTR enters several different routes, including a Rab5-dependent initial step to early endosomes, then either Rab11-dependent recycling back to the surface or Rab7-regulated movement to late endosomes or alternatively Rab9-mediated transit to the trans-Golgi network. Without any of these modulations ΔF508 CFTR rapidly disappears from and does not return to the cell surface, confirming that its altered structure is detected in the distal as well as proximal secretory pathway. Importantly, however, the mutant protein can be rescued at the plasma membrane by Rab11 overexpression, proteasome inhibitors, or inhibition of Rab5-dependent endocytosis. PMID:15075371

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

    PubMed Central

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

    2016-01-01

    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. PMID:26902995

  18. BRAF, PIK3CA, and HER2 Oncogenic Alterations According to KRAS Mutation Status in Advanced Colorectal Cancers with Distant Metastasis

    PubMed Central

    Koh, Jiwon; Kwak, Yoonjin; Seo, An Na; Park, Kyoung Un; Kim, Duck-Woo; Kang, Sung-Bum; Kim, Woo Ho; Lee, Hye Seung

    2016-01-01

    Background Anti-EGFR antibody–based treatment is an important therapeutic strategy for advanced colorectal cancer (CRC); despite this, several mutations—including KRAS, BRAF, and PIK3CA mutations, and HER2 amplification—are associated with the mechanisms underlying the development of resistance to anti-EGFR therapy. The aim of our study was to investigate the frequencies and clinical implications of these genetic alterations in advanced CRC. Methods KRAS, BRAF, and PIK3CA mutations were determined by Cobas real-time polymerase chain reaction (PCR) in 191 advanced CRC patients with distant metastasis. Microsatellite instability (MSI) status was determined by a fragmentation assay and HER2 amplification was assessed by silver in situ hybridization. In addition, KRAS mutations were investigated by the Sanger sequencing method in 97 of 191 CRC cases. Results Mutations in KRAS, BRAF, and PIK3CA were found in 104 (54.5%), 6 (3.1%), and 25 (13.1%) cases of advanced CRC, respectively. MSI-high status and HER2 amplification were observed in 3 (1.6%) and 16 (8.4%) cases, respectively. PIK3CA mutations were more frequently found in KRAS mutant type (18.3%) than KRAS wild type (6.9%) (P = 0.020). In contrast, HER2 amplifications and BRAF mutations were associated with KRAS wild type with borderline significance (P = 0.052 and 0.094, respectively). In combined analyses with KRAS, BRAF and HER2 status, BRAF mutations or HER2 amplifications were associated with the worst prognosis in the wild type KRAS group (P = 0.004). When comparing the efficacy of detection methods, the results of real time PCR analysis revealed 56 of 97 (57.7%) CRC cases with KRAS mutations, whereas Sanger sequencing revealed 49 cases (50.5%). Conclusions KRAS mutations were found in 54.5% of advanced CRC patients. Our results support that subgrouping using PIK3CA and BRAF mutation or HER2 amplification status, in addition to KRAS mutation status, is helpful for managing advanced CRC patients. PMID

  19. Prion-Specific Antibodies Produced in Wild-Type Mice.

    PubMed

    Heegaard, Peter M H; Bergström, Ann-Louise; Andersen, Heidi Gertz; Cordes, Henriette

    2015-01-01

    Peptide-specific antibodies produced against synthetic peptides are of high value in probing protein structure and function, especially when working with challenging proteins, including not readily available, non-immunogenic, toxic, and/or pathogenic proteins. Here, we present a straightforward method for production of mouse monoclonal antibodies (MAbs) against peptides representing two sites of interest in the bovine prion protein (boPrP), the causative agent of bovine spongiform encephalopathy ("mad cow disease") and new variant Creutzfeldt-Jakob's disease (CJD) in humans, as well as a thorough characterization of their reactivity with a range of normal and pathogenic (misfolded) prion proteins. It is demonstrated that immunization of wild-type mice with ovalbumin-conjugated peptides formulated with Freund's adjuvant induces a good immune response, including high levels of specific anti-peptide antibodies, even against peptides very homologous to murine protein sequences. In general, using the strategies described here for selecting, synthesizing, and conjugating peptides and immunizing 4-5 mice with 2-3 different peptides, high-titered antibodies reacting with the target protein are routinely obtained with at least one of the peptides after three to four immunizations with incomplete Freund's adjuvant. PMID:26424281

  20. Crystal structure of wild-type human procathepsin K.

    PubMed

    Sivaraman, J; Lalumière, M; Ménard, R; Cygler, M

    1999-02-01

    Cathepsin K is a lysosomal cysteine protease belonging to the papain superfamily. It has been implicated as a major mediator of osteoclastic bone resorption. Wild-type human procathepsin K has been crystallized in a glycosylated and a deglycosylated form. The latter crystals diffract better, to 3.2 A resolution, and contain four molecules in the asymmetric unit. The structure was solved by molecular replacement and refined to an R-factor of 0.194. The N-terminal fragment of the proregion forms a globular domain while the C-terminal segment is extended and shows substantial flexibility. The proregion interacts with the enzyme along the substrate binding groove and along the proregion binding loop (residues Ser138-Asn156). It binds to the active site in the opposite direction to that of natural substrates. The overall binding mode of the proregion to cathepsin K is similar to that observed in cathepsin L, caricain, and cathepsin B, but there are local differences that likely contribute to the specificity of these proregions for their cognate enzymes. The main observed difference is in the position of the short helix alpha3p (67p-75p), which occupies the S' subsites. As in the other proenzymes, the proregion utilizes the S2 subsite for anchoring by placing a leucine side chain there, according to the specificity of cathepsin K toward its substrate. PMID:10048321

  1. Crystal structure of wild-type human procathepsin K.

    PubMed Central

    Sivaraman, J.; Lalumière, M.; Ménard, R.; Cygler, M.

    1999-01-01

    Cathepsin K is a lysosomal cysteine protease belonging to the papain superfamily. It has been implicated as a major mediator of osteoclastic bone resorption. Wild-type human procathepsin K has been crystallized in a glycosylated and a deglycosylated form. The latter crystals diffract better, to 3.2 A resolution, and contain four molecules in the asymmetric unit. The structure was solved by molecular replacement and refined to an R-factor of 0.194. The N-terminal fragment of the proregion forms a globular domain while the C-terminal segment is extended and shows substantial flexibility. The proregion interacts with the enzyme along the substrate binding groove and along the proregion binding loop (residues Ser138-Asn156). It binds to the active site in the opposite direction to that of natural substrates. The overall binding mode of the proregion to cathepsin K is similar to that observed in cathepsin L, caricain, and cathepsin B, but there are local differences that likely contribute to the specificity of these proregions for their cognate enzymes. The main observed difference is in the position of the short helix alpha3p (67p-75p), which occupies the S' subsites. As in the other proenzymes, the proregion utilizes the S2 subsite for anchoring by placing a leucine side chain there, according to the specificity of cathepsin K toward its substrate. PMID:10048321

  2. Synthetic Lethal Therapy for KRAS Mutant Non-small-cell Lung Carcinoma with Nanoparticle-mediated CDK4 siRNA Delivery

    PubMed Central

    Mao, Cheng-Qiong; Xiong, Meng-Hua; Liu, Yang; Shen, Song; Du, Xiao-Jiao; Yang, Xian-Zhu; Dou, Shuang; Zhang, Pei-Zhuo; Wang, Jun

    2014-01-01

    The KRAS mutation is present in ~20% of lung cancers and has not yet been effectively targeted for therapy. This mutation is associated with a poor prognosis in non-small-cell lung carcinomas (NSCLCs) and confers resistance to standard anticancer treatment drugs, including epidermal growth factor receptor tyrosine kinase inhibitors. In this study, we exploited a new therapeutic strategy based on the synthetic lethal interaction between cyclin-dependent kinase 4 (CDK4) downregulation and the KRAS mutation to deliver micellar nanoparticles (MNPs) containing small interfering RNA targeting CDK4 (MNPsiCDK4) for treatment in NSCLCs harboring the oncogenic KRAS mutation. Following MNPsiCDK4 administration, CDK4 expression was decreased, accompanied by inhibited cell proliferation, specifically in KRAS mutant NSCLCs. However, this intervention was harmless to normal KRAS wild-type cells, confirming the proposed mechanism of synthetic lethality. Moreover, systemic delivery of MNPsiCDK4 significantly inhibited tumor growth in an A549 NSCLC xenograft murine model, with depressed expression of CDK4 and mutational KRAS status, suggesting the therapeutic promise of MNPsiCDK4 delivery in KRAS mutant NSCLCs via a synthetic lethal interaction between KRAS and CDK4. PMID:24496383

  3. Biosafety of recombinant and wild type nucleopolyhedroviruses as bioinsecticides.

    PubMed

    Ashour, Mohamed-Bassem; Ragheb, Didair A; El-Sheikh, El-Sayed A; Gomaa, El-Adarosy A; Kamita, Shizuo G; Hammock, Bruce D

    2007-06-01

    The entomopathogenic Autographa californica (Speyer) nucleopolyhedrovirus (AcMNPV) has been genetically modified to increase its speed of kill. The potential adverse effects of a recombinant AcMNPV (AcAaIT) as well as wild type AcMNPV and wild type Spodoptera littoralis NPV (SlNPV) were studied. Cotton plants were treated with these viruses at concentrations that were adjusted to resemble the recommended field application rate (4 x 10(12) PIBs/feddan, feddan = 4,200 m2) and 3rd instar larvae of S. littoralis were allowed to feed on the contaminated plants. SDS-PAGE, ELISA, and DNA analyses were used to confirm that larvae that fed on these plants were virus-infected. Polyhedra that were purified from the infected larvae were subjected to structural protein analysis. A 32 KDa protein was found in polyhedra that were isolated from all of the viruses. Subtle differences were found in the size and abundance of ODV proteins. Antisera against polyhedral proteins isolated from AcAaIT polyhedra were raised in rabbits. The terminal bleeds from rabbits were screened against four coating antigens (i.e., polyhedral proteins from AcAaIT, AcAaIT from field-infected larvae (AcAaIT-field), AcMNPV, and SlNPV) using a two-dimensional titration method with the coated antigen format. Competitive inhibition experiments were conducted in parallel to optimize antibody and coating antigen concentrations for ELISA. The IC50 values for each combination ranged from 1.42 to 163 microg/ml. AcAaIT-derived polyhedrin gave the lowest IC50 value, followed by those of SlNPV, AcAaIT-field, and AcMNPV. The optimized ELISA system showed low cross reactivity for AcMNPV (0.87%), AcAaIT-field (1.2%), and SlNPV (4.0%). Genomic DNAs isolated from AcAaIT that were passaged in larvae of S. littoralis that were reared in the laboratory or field did not show any detectable differences. Albino rats (male and female) that were treated with AcAaIT, AcMNPV or SlNPV (either orally or by intraperitoneal injection at

  4. Prevalence of K-Ras mutations in hepatocellular carcinoma: A Turkish Oncology Group pilot study

    PubMed Central

    TURHAL, NAZIM SERDAR; SAVAŞ, BERNA; ÇOŞKUN, ÖZNUR; BAŞ, EMINE; KARABULUT, BÜLENT; NART, DENIZ; KORKMAZ, TANER; YAVUZER, DILEK; DEMIR, GÖKHAN; DOĞUSOY, GÜLEN; ARTAÇ, MEHMET

    2015-01-01

    Hepatocellular carcinoma (HCC) is the fifth most common male-predominant type of cancer worldwide. There is no effective treatment regimen available for advanced-stage disease and chemotherapy is generally ineffective in these patients. The number of studies on the prevalence of K-Ras mutations in HCC patients is currently limited. A total of 58 patients from 6 comprehensive cancer centers in 4 metropolitan cities of Turkey were enrolled in this study. Each center committed to enroll approximately 10 random patients whose formalin-fixed paraffin-embedded tumor tissues were available for K-Ras, exon 2 genotyping. Two methods were applied based on the availability of adequate amounts of tumor DNA. In the first method, the samples were processed using TheraScreen. The genomic DNA was further used to detect the 7 most frequent somatic mutations (35G>A; 35G>C; 35G>T; 34G>A; 34G>C; 34G>T and 38G>A) in codons 12 and 13 in exon 2 of the K-Ras oncogene by quantitative polymerase chain reaction (PCR). In the second method, the genomic DNA was amplified by PCR using primers specific for K-Ras exon 2 with the GML SeqFinder Sequencing System's KRAS kit. The identified DNA sequence alterations were confirmed by sequencing both DNA strands in two independent experiments with forward and reverse primers. A total of 40 samples had adequate tumor tissue for the mutation analysis. A total of 33 (82.5%) of the investigated samples harbored no mutations in exon 2. All the mutations were identified via a direct sequencing technique, whereas none were identified by TheraScreen. In conclusion, in our patients, HCC exhibited a remarkably low (<20%) K-Ras mutation rate. Patients harboring K-Ras wild-type tumors may be good candidates for treatment with epidermal growth factor inhibitors, such as cetuximab. PMID:26807232

  5. Wild-type and mutated presenilins 2 trigger p53-dependent apoptosis and down-regulate presenilin 1 expression in HEK293 human cells and in murine neurons.

    PubMed

    Alves da Costa, Cristine; Paitel, Erwan; Mattson, Mark P; Amson, Robert; Telerman, Adam; Ancolio, Karine; Checler, Frédéric; Mattson, Marc P

    2002-03-19

    Presenilins 1 and 2 are two homologous proteins that, when mutated, account for most early onset Alzheimer's disease. Several lines of evidence suggest that, among various functions, presenilins could modulate cell apoptotic responses. Here we establish that the overexpression of presenilin 2 (PS2) and its mutated form Asn-141-Ile-PS2 alters the viability of human embryonic kidney (HEK)293 cells as established by combined trypan blue exclusion, sodium 3'-[1-(phenylamino-carbonyl)-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene sulfonic acid hydrate assay, and propidium iodide incorporation FACS analyses. The two parent proteins increase the acetyl-DEVD-al-sensitive caspase-3-like activity in both HEK293 cells and Telencephalon specific murine neurons, modulate Bax and bcl-2 expressions, and enhance cytochrome C translocation into the cytosol. We show that overexpression of both wild-type and mutated PS2 increases p53-like immunoreactivity and transcriptional activity. We also establish that wild-type- and mutated PS2-induced caspase activation is reduced by p53 antisense approach and by pifithrin-alpha, a chemical inhibitor of p53. Furthermore, mouse fibroblasts in which the PS2 gene has been knocked out exhibited strongly reduced p53-transcriptional activity. Finally, we establish that the overexpression of both wild-type and mutated PS2 is accompanied by a drastic reduction of endogenous presenilin 1 (PS1) expression. Interestingly, pifithrin-alpha diminished endogenous PS2 immunoreactivity, whereas the inhibitor increases PS1 expression. Altogether, our data demonstrate that wild-type and familial Alzheimer's disease-linked PS2 trigger apoptosis and down-regulate PS1 expression through p53-dependent mechanisms. PMID:11904448

  6. Clinical Relevance of KRAS in Human Cancers

    PubMed Central

    Jančík, Sylwia; Drábek, Jiří; Radzioch, Danuta; Hajdúch, Marián

    2010-01-01

    The KRAS gene (Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) is an oncogene that encodes a small GTPase transductor protein called KRAS. KRAS is involved in the regulation of cell division as a result of its ability to relay external signals to the cell nucleus. Activating mutations in the KRAS gene impair the ability of the KRAS protein to switch between active and inactive states, leading to cell transformation and increased resistance to chemotherapy and biological therapies targeting epidermal growth factor receptors. This review highlights some of the features of the KRAS gene and the KRAS protein and summarizes current knowledge of the mechanism of KRAS gene regulation. It also underlines the importance of activating mutations in the KRAS gene in relation to carcinogenesis and their importance as diagnostic biomarkers, providing clues regarding human cancer patients' prognosis and indicating potential therapeutic approaches. PMID:20617134

  7. Effect of KRAS codon13 mutations in patients with advanced colorectal cancer (advanced CRC) under oxaliplatin containing chemotherapy. Results from a translational study of the AIO colorectal study group

    PubMed Central

    2012-01-01

    Background To evaluate the value of KRAS codon 13 mutations in patients with advanced colorectal cancer (advanced CRC) treated with oxaliplatin and fluoropyrimidines. Methods Tumor specimens from 201 patients with advanced CRC from a randomized, phase III trial comparing oxaliplatin/5-FU vs. oxaliplatin/capecitabine were retrospectively analyzed for KRAS mutations. Mutation data were correlated to response data (Overall response rate, ORR), progression-free survival (PFS) and overall survival (OS). Results 201 patients were analysed for KRAS mutation (61.2% males; mean age 64.2 ± 8.6 years). KRAS mutations were identified in 36.3% of tumors (28.8% in codon 12, 7.4% in codon 13). The ORR in codon 13 patients compared to codon 12 and wild type patients was significantly lower (p = 0.008). There was a tendency for a better overall survival in KRAS wild type patients compared to mutants (p = 0.085). PFS in all patients was not different in the three KRAS genetic groups (p = 0.72). However, we found a marked difference in PFS between patients with codon 12 and 13 mutant tumors treated with infusional 5-FU versus capecitabine based regimens. Conclusions Our data suggest that the type of KRAS mutation may be of clinical relevance under oxaliplatin combination chemotherapies without the addition of monoclonal antibodies in particular when overall response rates are important. Trial registration number 2002-04-017 PMID:22876876

  8. Glycoproteomic Approach Identifies KRAS as a Positive Regulator of CREG1 in Non-small Cell Lung Cancer Cells

    PubMed Central

    Clark, David J.; Mei, Yuping; Sun, Shisheng; Zhang, Hui; Yang, Austin J.; Mao, Li

    2016-01-01

    Protein glycosylation plays a fundamental role in a multitude of biological processes, and the associated aberrant expression of glycoproteins in cancer has made them attractive biomarkers and therapeutic targets. In this study, we examined differentially expressed glycoproteins in cell lines derived from three different states of lung tumorigenesis: an immortalized bronchial epithelial cell (HBE) line, a non-small cell lung cancer (NSCLC) cell line harboring a Kirsten rat sarcoma viral oncogene homolog (KRAS) activation mutation and a NSCLC cell line harboring an epidermal growth factor receptor (EGFR) activation deletion. Using a Triple SILAC proteomic quantification strategy paired with hydrazide chemistry N-linked glycopeptide enrichment, we quantified 118 glycopeptides in the three cell lines derived from 82 glycoproteins. Proteomic profiling revealed 27 glycopeptides overexpressed in both NSCLC cell lines, 6 glycopeptides overexpressed only in the EGFR mutant cells and 19 glycopeptides overexpressed only in the KRAS mutant cells. Further investigation of a panel of NSCLC cell lines found that Cellular repressor of E1A-stimulated genes (CREG1) overexpression was closely correlated with KRAS mutation status in NSCLC cells and could be down-regulated by inhibition of KRAS expression. Our results indicate that CREG1 is a down-stream effector of KRAS in a sub-type of NSCLC cells and a novel candidate biomarker or therapeutic target for KRAS mutant NSCLC. PMID:26722374

  9. Identification of target genes for wild type and truncated HMGA2 in mesenchymal stem-like cells

    PubMed Central

    2010-01-01

    Background The HMGA2 gene, coding for an architectural transcription factor involved in mesenchymal embryogenesis, is frequently deranged by translocation and/or amplification in mesenchymal tumours, generally leading to over-expression of shortened transcripts and a truncated protein. Methods To identify pathways that are affected by sarcoma-associated variants of HMGA2, we have over-expressed wild type and truncated HMGA2 protein in an immortalized mesenchymal stem-like cell (MSC) line, and investigated the localisation of these proteins and their effects on differentiation and gene expression patterns. Results Over-expression of both transgenes blocked adipogenic differentiation of these cells, and microarray analysis revealed clear changes in gene expression patterns, more pronounced for the truncated protein. Most of the genes that showed altered expression in the HMGA2-overexpressing cells fell into the group of NF-κB-target genes, suggesting a central role for HMGA2 in this pathway. Of particular interest was the pronounced up-regulation of SSX1, already implicated in mesenchymal oncogenesis and stem cell functions, only in cells expressing the truncated protein. Furthermore, over-expression of both HMGA2 forms was associated with a strong repression of the epithelial marker CD24, consistent with the reported low level of CD24 in cancer stem cells. Conclusions We conclude that the c-terminal part of HMGA2 has important functions at least in mesenchymal cells, and the changes in gene expression resulting from overexpressing a protein lacking this domain may add to the malignant potential of sarcomas. PMID:20576167

  10. Cis-acting elements in its 3′ UTR mediate post-transcriptional regulation of KRAS

    PubMed Central

    Kim, Minlee; Kogan, Nicole; Slack, Frank J.

    2016-01-01

    Multiple RNA-binding proteins and non-coding RNAs, such as microRNAs (miRNAs), are involved in post-transcriptional gene regulation through recognition motifs in the 3′ untranslated region (UTR) of their target genes. The KRAS gene encodes a key signaling protein, and its messenger RNA (mRNA) contains an exceptionally long 3′ UTR; this suggests that it may be subject to a highly complex set of regulatory processes. However, 3′ UTR-dependent regulation of KRAS expression has not been explored in detail. Using extensive deletion and mutational analyses combined with luciferase reporter assays, we have identified inhibitory and stabilizing cis-acting regions within the KRAS 3′ UTR that may interact with miRNAs and RNA-binding proteins, such as HuR. Particularly, we have identified an AU-rich 49-nt fragment in the KRAS 3′ UTR that is required for KRAS 3′ UTR reporter repression. This element contains a miR-185 complementary element, and we show that overexpression of miR-185 represses endogenous KRAS mRNA and protein in vitro. In addition, we have identified another 49-nt fragment that is required to promote KRAS 3′ UTR reporter expression. These findings indicate that multiple cis-regulatory motifs in the 3′ UTR of KRAS finely modulate its expression, and sequence alterations within a binding motif may disrupt the precise functions of trans-regulatory factors, potentially leading to aberrant KRAS expression. PMID:26930719

  11. Accumulation of wild-type p53 protein in astrocytomas is not mediated by MDM2 gene amplification

    SciTech Connect

    Rubio, M.P.; Louis, D.N. Harvard Medical School, Boston, MA )

    1993-05-01

    The authors have previously described ten cases of astrocytoma (three WHO grade II, four grade III and four grade IV) with seemingly contradictory results on immunohistochemical analysis of the p53 protein and molecular genetic analysis of the p53 gene. Fixed, embedded tissues from these cases were immunohistochemically positive with the PAb 1801 antibody, which supposedly implies the presence of mutant protein. These ten cases, however, did not have mutations in exons 5 through 8 of the p53 gene, the conserved regions in which almost all human mutations have been described. The authors suggested that these cases might either represent overexpression of wild-type p53 protein (since the PAb 1801 antibody reacts with both wild-type and mutant p53 protein) or mutations in less conserved regions of the gene. To investigate these possibilities further, they performed single strand conformational polymorphism analysis and DNA sequencing on p53 exons 4, 9 and 10 in the nine cases with available DNA, since rare mutations have been noted at these loci. None of the cases showed alterations, making it highly unlikely that these tumors harbor mutations in exons of the p53 gene. They also performed immunohistochemistry on frozen sections from seven available tumors, using the mutant-specific antibody PAb 240 in addition to PAb 1801. All tumors continued to show positive staining with PAb 1801, but only one tumor reacted with PAb 240. The results support the hypothesis that the accumulated p53 protein in most cases is wild-type. Because the product of the MDM2 oncogene can bind to wild-type p53 protein, and because MDM2 amplification has recently been demonstrated in human tumors, the authors evaluated MDM2 amplification in the nine astrocytomas with available DNA. Using slot blot analysis with a 96-base pair, PCR-generated probe to the first exon of the MDM2 gene, they were unable to show MDM2 gene amplification in these tumors or in other assayed astrocytomas.

  12. A human papillomavirus type 18 E6/E7 transgene sensitizes mouse lens cells to human wild-type p53-mediated apoptosis.

    PubMed

    Nakamura, T; Williams-Simons, L; Westphal, H

    1997-06-26

    We have studied the concerted action of factors that influence the balance between cell proliferation and cell death in the developing lens of transgenic mice. We show that a human papillomavirus type 18 (HPV18) E6/E7 transgene that predominantly expresses the viral E7 gene product triggers apoptosis in a dose dependent manner, and causes retardation of lens growth or microphakia. E7 is known to inactivate pRB, the product of the retinoblastoma gene, and to enhance the action of p53. Our earlier work had demonstrated that over-expression of p53 itself can cause apoptosis of lens cells, and that a mutant p53 allele can interfere with this process. In the present study, we examined lenses that simultaneously express different constellations of the HPV18 E6/E7, wild-type and mutant human p53, and wild-type human pRB transgenes. We observed that lens cells expressing the HPV18 transgene are more sensitive to wild-type human p53 action than normal lens cells. As a result, there is severe microphakia in lenses that express both the HPV18 and the wild-type p53 transgenes. By contrast, apoptosis was reduced in lenses that co-expressed the HPV18 and either the pRB or the mutant p53 transgene. We conclude that levels of wild-type p53 are critical, and that any excess of p53 or suppression of pRB can cause cell death. Our results encourage attempts to counteract the deleterious action of human papillomaviruses in cervical cancer by a combination of measures that decrease cell proliferation and enhance apoptosis. PMID:9223662

  13. Wild-Type and Non-Wild-Type Mycobacterium tuberculosis MIC Distributions for the Novel Fluoroquinolone Antofloxacin Compared with Those for Ofloxacin, Levofloxacin, and Moxifloxacin

    PubMed Central

    Yu, Xia; Wang, Guirong; Chen, Suting; Wei, Guomei; Shang, Yuanyuan; Dong, Lingling; Schön, Thomas; Moradigaravand, Danesh; Peacock, Sharon J.

    2016-01-01

    Antofloxacin (AFX) is a novel fluoroquinolone that has been approved in China for the treatment of infections caused by a variety of bacterial species. We investigated whether it could be repurposed for the treatment of tuberculosis by studying its in vitro activity. We determined the wild-type and non-wild-type MIC ranges for AFX as well as ofloxacin (OFX), levofloxacin (LFX), and moxifloxacin (MFX), using the microplate alamarBlue assay, of 126 clinical Mycobacterium tuberculosis strains from Beijing, China, of which 48 were OFX resistant on the basis of drug susceptibility testing on Löwenstein-Jensen medium. The MIC distributions were correlated with mutations in the quinolone resistance-determining regions of gyrA (Rv0006) and gyrB (Rv0005). Pharmacokinetic/pharmacodynamic (PK/PD) data for AFX were retrieved from the literature. AFX showed lower MIC levels than OFX but higher MIC levels than LFX and MFX on the basis of the tentative epidemiological cutoff values (ECOFFs) determined in this study. All strains with non-wild-type MICs for AFX harbored known resistance mutations that also resulted in non-wild-type MICs for LFX and MFX. Moreover, our data suggested that the current critical concentration of OFX for Löwenstein-Jensen medium that was recently revised by the World Health Organization might be too high, resulting in the misclassification of phenotypically non-wild-type strains with known resistance mutations as wild type. On the basis of our exploratory PK/PD calculations, the current dose of AFX is unlikely to be optimal for the treatment of tuberculosis, but higher doses could be effective. PMID:27324769

  14. Wild-Type and Non-Wild-Type Mycobacterium tuberculosis MIC Distributions for the Novel Fluoroquinolone Antofloxacin Compared with Those for Ofloxacin, Levofloxacin, and Moxifloxacin.

    PubMed

    Yu, Xia; Wang, Guirong; Chen, Suting; Wei, Guomei; Shang, Yuanyuan; Dong, Lingling; Schön, Thomas; Moradigaravand, Danesh; Parkhill, Julian; Peacock, Sharon J; Köser, Claudio U; Huang, Hairong

    2016-09-01

    Antofloxacin (AFX) is a novel fluoroquinolone that has been approved in China for the treatment of infections caused by a variety of bacterial species. We investigated whether it could be repurposed for the treatment of tuberculosis by studying its in vitro activity. We determined the wild-type and non-wild-type MIC ranges for AFX as well as ofloxacin (OFX), levofloxacin (LFX), and moxifloxacin (MFX), using the microplate alamarBlue assay, of 126 clinical Mycobacterium tuberculosis strains from Beijing, China, of which 48 were OFX resistant on the basis of drug susceptibility testing on Löwenstein-Jensen medium. The MIC distributions were correlated with mutations in the quinolone resistance-determining regions of gyrA (Rv0006) and gyrB (Rv0005). Pharmacokinetic/pharmacodynamic (PK/PD) data for AFX were retrieved from the literature. AFX showed lower MIC levels than OFX but higher MIC levels than LFX and MFX on the basis of the tentative epidemiological cutoff values (ECOFFs) determined in this study. All strains with non-wild-type MICs for AFX harbored known resistance mutations that also resulted in non-wild-type MICs for LFX and MFX. Moreover, our data suggested that the current critical concentration of OFX for Löwenstein-Jensen medium that was recently revised by the World Health Organization might be too high, resulting in the misclassification of phenotypically non-wild-type strains with known resistance mutations as wild type. On the basis of our exploratory PK/PD calculations, the current dose of AFX is unlikely to be optimal for the treatment of tuberculosis, but higher doses could be effective. PMID:27324769

  15. Challenges in detecting pre-malignant pancreatic lesions during acute pancreatitis using a serum microRNA assay: a study based on KrasG12D transgenic mice

    PubMed Central

    Hong, Xiafei; Zhang, Jie; Wu, Qiao; Wang, Wenze; Ye, Adam Yongxin; Song, Wei; Dai, Hongmei; Wang, Xianze; Wu, Fan; You, Lei; Wu, Wenming; Zhao, Yupei

    2016-01-01

    Caerulein-induced acute pancreatitis accelerates the progression of pancreatic intraepithelial neoplasia (PanIN) lesions in a pancreas-specific KrasG12D mouse model. The purpose of this study was to explore whether serum microRNAs (miRNAs) can serve as sensitive biomarkers to detect occult PanIN in the setting of acute pancreatitis. Serum miRNA profiles were quantified by an array-based method and normalized by both Variance Stabilization Normalization (VSN) and invariant methods. Individual miRNAs were validated by TaqMan real-time PCR with synthetic spike-in C. elegans miRNAs as external controls. Serum miRNA profiles distinguished KrasG12D mice with pancreatitis from wild-type mice without pancreatitis, but failed to differentiate KrasG12D mice with pancreatitis from wild-type mice with pancreatitis. Most individual miRNAs that increased in KrasG12D mice with pancreatitis were not significantly different between KrasG12D mice without pancreatitis and wild-type mice without pancreatitis. Mechanistically, Gene Set Enrichment Analysis (GSEA) of the mRNA array data and immunohistochemical assays showed that caerulein-induced acute pancreatitis involved acinar cell loss and immune cell infiltration, which might contribute to serum miRNA profile changes. This study highlighted the challenges in using sensitive serum miRNA biomarker screening for the early detection of pancreatic malignancies during acute pancreatitis. PMID:27009811

  16. Role of Kras Status in Patients with Metastatic Colorectal Cancer Receiving First-Line Chemotherapy plus Bevacizumab: A TTD Group Cooperative Study

    PubMed Central

    Díaz-Rubio, Eduardo; Gómez-España, Auxiliadora; Massutí, Bartomeu; Sastre, Javier; Reboredo, Margarita; Manzano, José Luis; Rivera, Fernando; Safont, MªJosé; Montagut, Clara; González, Encarnación; Benavides, Manuel; Marcuello, Eugenio; Cervantes, Andrés; Martínez de Prado, Purificación; Fernández-Martos, Carlos; Arrivi, Antonio; Bando, Inmaculada; Aranda, E.; Gómez, A.; Massutí, B.; Yuste, A.; Rubio, E. Díaz; Sastre, J.; Valladares, M.; Abad, A.; Rivera, F.; Safont, MªJosé; Gallén, M.; González, E.; Benavides, M.; Marcuello, E.; Tobeña, M.; Cervantes, A.; Martínez de Prado, P.; Fernández-Martos, C.; Arrivi, A.; López-Ladrón, A.; Lacasta, A.; Llanos, M.; Remón, J.; Anton, A.; Vicent, J. Mª.; Gala´n, A.; Dueñas, R.; Tabernero, J. Mª.; Manzano, H.; Gómez, Mª. J.; Alfaro, J.; Losa, F.; Escudero, P.; García, T.; García López, J. L.; de Paredes, Mª L. García; Velasco, A.; Almenar, D.; Vera, R.; García Puche, J. L.; Carrato, A.; Lescure, A. Rodriguez; Jiménez, E.; Alberola, V.; García-Foncillas, J.; Constenla, M.; Ruiz, A.; Bueso, P.; Cabrera, E.; del Río,, L.; Ponce, J.; Oltra, A.; Checa, T.; Etxeberría, A.; Alonso, C.

    2012-01-01

    Background In the MACRO study, patients with metastatic colorectal cancer (mCRC) were randomised to first-line treatment with 6 cycles of capecitabine and oxaliplatin (XELOX) plus bevacizumab followed by either single-agent bevacizumab or XELOX plus bevacizumab until disease progression. An additional retrospective analysis was performed to define the prognostic value of tumour KRAS status on progression-free survival (PFS), overall survival (OS) and response rates. Methodology/Principal Findings KRAS data (tumour KRAS status and type of mutation) were collected by questionnaire from participating centres that performed KRAS analyses. These data were then cross-referenced with efficacy data for relevant patients in the MACRO study database. KRAS status was analysed in 394 of the 480 patients (82.1%) in the MACRO study. Wild-type (WT) KRAS tumours were found in 219 patients (56%) and mutant (MT) KRAS in 175 patients (44%). Median PFS was 10.9 months for patients with WT KRAS and 9.4 months for patients with MT KRAS tumours (p = 0.0038; HR: 1.40; 95% CI:1.12–1.77). The difference in OS was also significant: 26.7 months versus 18.0 months for WT versus MT KRAS, respectively (p = 0.0002; HR: 1.55; 95% CI: 1.23–1.96). Univariate and multivariate analyses showed that KRAS was an independent variable for both PFS and OS. Responses were observed in 126 patients (57.5%) with WT KRAS tumours and 76 patients (43.4%) with MT KRAS tumours (p = 0.0054; OR: 1.77; 95% CI: 1.18–2.64). Conclusions/Significance This analysis of the MACRO study suggests a prognostic role for tumour KRAS status in patients with mCRC treated with XELOX plus bevacizumab. For both PFS and OS, KRAS status was an independent factor in univariate and multivariate analyses. PMID:23174912

  17. An oligonucleotide-tagged microarray for routine diagnostics of colon cancer by genotyping KRAS mutations.

    PubMed

    Liu, Yuliang; Gudnason, Haukur; Li, Yi-Ping; Bang, Dang Duong; Wolff, Anders

    2014-10-01

    Colorectal cancer (CRC) is one of the most prevalent types of cancer, causing significant morbidity and mortality worldwide. CRC is curable if diagnosed at an early stage. Mutations in the oncogene KRAS play a critical role in early development of CRC. Detection of activated KRAS is of diagnostic and therapeutic importance. In this study, KRAS gene fragments containing mutations in codon 12 were amplified by multiplex PCR using a 5'-Cy5-labeled reverse primer in combination with 3'-mutation-specific forward primers that were linked with four unique nucleotide-sequence tags at the 5'-end. The Cy5-labeled reverse primer was extended under PCR amplification to the 5'-end of the mutation-specific forward primers and thus included the complimentary sequence of the tag. PCR products were hybridized to tag-probes immobilized on various substrates and detected by a scanner. Our results indicate that all mutations at codon 12 of KRAS derived from cancer cells and clinical samples could be unambiguously detected. KRAS mutations were accurately detected when the mutant DNA was present only in 10% of the starting mixed materials including wild-type genomic DNA, which was isolated from either cancer cells or spiked fecal samples. The immobilized tag-probes were stable under multiple thermal cycling treatments, allowing re-use of the tag-microarray and further optimization to solid PCR. Our results demonstrated that a novel oligonucleotide-tagged microarray system has been developed which would be suitable to be used for detection of KRAS mutations and clinical diagnosis of CRC. PMID:25018048

  18. p16 and K-ras gene mutations in the intraductal precursors of human pancreatic adenocarcinoma.

    PubMed

    Moskaluk, C A; Hruban, R H; Kern, S E

    1997-06-01

    Pancreatic adenocarcinoma is thought to arise from a noninvasive neoplastic precursor, the pancreatic intraductal lesion (PIL). Mutations of the K-ras gene are known to occur in PILs, but their high prevalence among PILs within the general population probably limit the use of K-ras as a marker of eventual clinical risk. In search of genetic constellations that might indicate the progression of some PILs toward an invasive phenotype, mutations at both the K-ras and p16 genes were sought within PILs of 10 pancreata resected for adenocarcinoma. K-ras mutations were present in most PILs and in nearly all PILs having nuclear atypia. In half of the patients, two or more unique K-ras mutations were identified among distinct PILs, which is evidence for the separate clonal evolution of multiple pancreatic neoplasms within individual patients. p16 alterations (one homozygous deletion and three point mutations) were found in 4 of the 10 carcinomas; these four pancreata harbored p16 alterations in three of nine PILs, of which one was a "histologically early" lesion. Two patients had p16 alterations in PILs matching those of the associated carcinomas. p16 mutations were not found in PILs of pancreata having wild-type p16 in the carcinoma, nor were they found in ducts having normal histology. It is suggested that alterations of the p16 gene affect a subset of PILs that contain mutations of the K-ras gene and that these mutations might identify high-risk precursors of the invasive malignancy. PMID:9187111

  19. KRAS, BRAF and PIK3CA Status in Squamous Cell Anal Carcinoma (SCAC)

    PubMed Central

    Giannini, Massimo; Freier, Eva; Tamberi, Stefano; Scarpi, Emanuela; Passardi, Alassandro; Zoli, Wainer; Ragazzini, Angela; Amadori, Dino; Frassineti, Giovanni Luca

    2014-01-01

    Anti-EGFR therapy appears to be a potential treatment option for squamous cell anal carcinoma (SCAC). KRAS mutation is a rare event in SCAC, indicating the absence of the principal mechanism of resistance to this type of therapy. However, no information is available from the literature regarding the status of BRAF or PIK3CA in this cancer type. We analysed KRAS, BRAF and PIK3CA status in SCAC patients in relation to the clinical-pathological characteristics of patients and to the presence of the human papilloma virus (HPV). One hundred and three patients were treated with the Nigro scheme for anal cancer from March 2001 to August 2012. Fifty patients were considered for the study as there was insufficient paraffin-embedded tumour tissue to perform molecular analysis the remaining 53. DNA was extracted from paraffin-embedded sections. KRAS, BRAF and PIK3CA gene status and HPV genotype were evaluated by pyrosequencing. KRAS and BRAF genes were wild-type in all cases. Conversely, PIK3CA gene was found to be mutated in 11 (22%) cases. In particular, 8 mutations occurred in exon 9 and 3 in exon 20 of the PIK3CA gene. These findings suggest that SCAC could potentially respond to an anti-EGFR drug. PIK3CA mutation may be involved in the process of carcinogenesis in some cases of SCAC. PMID:24642661

  20. Impact of genetic profiles on the efficacy of anti-EGFR antibodies in metastatic colorectal cancer with KRAS mutation.

    PubMed

    Kishiki, Tomokazu; Ohnishi, Hiroaki; Masaki, Tadahiko; Ohtsuka, Kouki; Ohkura, Yasuo; Furuse, Jyunji; Sugiyama, Masanori; Watanabe, Takashi

    2014-07-01

    Reports indicate that, even in KRAS-mutated colon cancer, there are subsets of patients who benefit from anti-EGFR monoclonal antibody (MoAb) treatment. The aim of the present study was to identify genetic profiles that contribute to the responsiveness of metastatic colorectal cancer (mCRC) to anti-EGFR MoAb. We retrospectively evaluated the efficacy of anti-EGFR MoAb in mCRC patients with KRAS mutations according to KRAS mutational subtypes, BRAF and PIK3CA mutational status and PTEN and MET expression. Among 21 patients with KRAS-mutant tumors, 8 (38%) harbored p.G13D, 7 (33%) harbored p.G12V, 5 (24%) harbored p.G12D, and 1 (5%) harbored p.G12C mutation. Patients with the p.G13D mutation exhibited a significantly higher disease control rate than patients with other KRAS mutations (P=0.042), and tended to show a longer progression-free survival (PFS) than patients with other KRAS mutations with marginal significance (P=0.074). Patients with loss of PTEN had significantly shorter PFS than those with normal PTEN expression in patients with KRAS mutations (P=0.044). MET overexpression was significantly associated with shorter PFS compared to normal MET expression in patients with KRAS mutations (P=0.016). Our data demonstrated the potential utility of alterations in PTEN and MET expression as predictive markers for response to anti-EGFR MoAbs in mCRC patients with KRAS mutations. In addition, we confirmed the predictive value of the KRAS p.G13D mutation for better response to anti-EGFR therapies in comparison with other KRAS mutations. PMID:24839940

  1. Spaceflight influences both mucosal and peripheral cytokine production in PTN-Tg and wild type mice.

    PubMed

    McCarville, Justin L; Clarke, Sandra T; Shastri, Padmaja; Liu, Yi; Kalmokoff, Martin; Brooks, Stephen P J; Green-Johnson, Julia M

    2013-01-01

    Spaceflight is associated with several health issues including diminished immune efficiency. Effects of long-term spaceflight on selected immune parameters of wild type (Wt) and transgenic mice over-expressing pleiotrophin under the human bone-specific osteocalcin promoter (PTN-Tg) were examined using the novel Mouse Drawer System (MDS) aboard the International Space Station (ISS) over a 91 day period. Effects of this long duration flight on PTN-Tg and Wt mice were determined in comparison to ground controls and vivarium-housed PTN-Tg and Wt mice. Levels of interleukin-2 (IL-2) and transforming growth factor-beta1 (TGF-β1) were measured in mucosal and systemic tissues of Wt and PTN-Tg mice. Colonic contents were also analyzed to assess potential effects on the gut microbiota, although no firm conclusions could be made due to constraints imposed by the MDS payload and the time of sampling. Spaceflight-associated differences were observed in colonic tissue and systemic lymph node levels of IL-2 and TGF-β1 relative to ground controls. Total colonic TGF-β1 levels were lower in Wt and PTN-Tg flight mice in comparison to ground controls. The Wt flight mouse had lower levels of IL-2 and TGF-β1 compared to the Wt ground control in both the inguinal and brachial lymph nodes, however this pattern was not consistently observed in PTN-Tg mice. Vivarium-housed Wt controls had higher levels of active TGF-β1 and IL-2 in inguinal lymph nodes relative to PTN-Tg mice. The results of this study suggest compartmentalized effects of spaceflight and on immune parameters in mice. PMID:23874826

  2. SURVIVAL AND EFFECTS OF WILD-TYPE, MUTANT, AND RECOMBINANT STREPTOMYCES IN A SOIL ECOSYSTEM

    EPA Science Inventory

    In a laboratory simulation, selected wild-type, mutant, and recombinant Streptomyces were released into a silt loam soil. trains included genetically enhanced lignin decomposers and those expressing recombinant plasmids. heir survival and effects on soil organic carbon mineraliza...

  3. Development of a ligase detection reaction/CGE method using a LIF dual-channel detection system for direct identification of allelic composition of mutated DNA in a mixed population of excess wild-type DNA.

    PubMed

    Hamada, Mariko; Shimase, Koji; Noda, Keiichi; Tsukagoshi, Kazuhiko; Hashimoto, Masahiko

    2013-05-01

    We developed an inexpensive LIF dual-channel detection system and applied it to a ligase detection reaction (LDR)/CGE method to identify the allelic composition of low-abundance point mutations in a large excess of wild-type DNA in a single reaction with a high degree of certainty. Ligation was performed in a tube with a nonlabeled common primer and multiplex discriminating primers, each labeled with a different standard fluorophore. The discriminating primers were directed against three mutant variations in codon 12 of the K-ras oncogene that have a high diagnostic value for colorectal cancer. LDR products generated from a particular K-ras mutation through successful ligation events were separated from remaining discriminating primers by CGE, followed by LIF detection using the new system, which consists of two photomultiplier tubes, each with a unique optical filter. Each fluorophore label conjugated to the corresponding LDR product produced a distinct fluorescence signal intensity ratio from the two detection channels, allowing spectral discrimination of the three labels. The ability of this system to detect point mutations in a wild-type sequence-dominated population, and to disclose their allelic composition, was thus demonstrated successfully. PMID:23463388

  4. Comparison between NOx Evolution Mechanisms of Wild-Type and nr1 Mutant Soybean Leaves 1

    PubMed Central

    Klepper, Lowell

    1990-01-01

    The nr1 soybean (Glycine max [L.] Merr.) mutant does not contain the two constitutive nitrate reductases, one of which is responsible for enzymic conversion of nitrite to NOx (NO + NO2). It was tested for possible nonenzymic NOx formation and evolution because of known chemical reactions between NO2− and plant metabolites and the instability of nitrous acid. It did not evolve NOx during the in vivo NR assay, but intact leaves did evolve small amounts of NOx under dark, anaerobic conditions. Experiments were conducted to compare NO3− reduction, NO2− accumulation, and the NOx evolution processes of the wild type (cv Williams) and the nr1 mutant. In vivo NR assays showed that wild-type leaves had three times more NO3− reducing capacity than the nr1 mutant. NOx evolution from intact, anerobic nr1 leaves was approximately 10 to 20% that from wild-type leaves. Nitrite content of the nr1 mutant leaves was usually higher than wild type due to low NOx evolution. Lag times and threshold NO2− concentrations for NOx evolution were similar for the two genotypes. While only 1 to 2% of NOx from wild type is NO2, the nr1 mutant evolved 15 to 30% NO2. The kinetic patterns of NOx evolution with time weré completely different for the mutant and wild type. Comparisons of light and heat treatments also gave very different results. It is generally accepted that the NOx evolution by wild type is primarily an enzymic conversion of NO2− to NO. However, this report concludes that NOx evolution by the nr1 mutant was due to nonenzymic, chemical reactions between plant metabolites and accumulated NO2− and/or decomposition of nitrous acid. Nonenzymic NOx evolution probably also occurs in wild type to a degree but could be easily masked by high rates of the enzymic process. PMID:16667445

  5. KRAS-driven ROS promote malignant transformation

    PubMed Central

    Suh, Yongjoon; Lee, Su-Jae

    2015-01-01

    The mechanism underlying KRAS (Kirsten rat sarcoma viral oncogene homolog)-driven cellular transformation remains unclear because of the complexity of its downstream effectors. Park et al. recently reported that levels of reactive oxygen species (ROS) are increased by KRAS and are responsible for KRAS-driven malignant transformation, and further identified the signaling cascade involved as KRAS/p38/PDPK1/PKCδ/p47phox/NOX1. These findings provide new insight into the molecular mechanisms governing KRAS-driven malignant transformation. PMID:27308397

  6. Co-fibrillogenesis of Wild-type and D76N β2-Microglobulin

    PubMed Central

    Natalello, Antonino; Mangione, P. Patrizia; Giorgetti, Sofia; Porcari, Riccardo; Marchese, Loredana; Zorzoli, Irene; Relini, Annalisa; Ami, Diletta; Faravelli, Giulia; Valli, Maurizia; Stoppini, Monica; Doglia, Silvia M.; Bellotti, Vittorio; Raimondi, Sara

    2016-01-01

    The amyloidogenic variant of β2-microglobulin, D76N, can readily convert into genuine fibrils under physiological conditions and primes in vitro the fibrillogenesis of the wild-type β2-microglobulin. By Fourier transformed infrared spectroscopy, we have demonstrated that the amyloid transformation of wild-type β2-microglobulin can be induced by the variant only after its complete fibrillar conversion. Our current findings are consistent with preliminary data in which we have shown a seeding effect of fibrils formed from D76N or the natural truncated form of β2-microglobulin lacking the first six N-terminal residues. Interestingly, the hybrid wild-type/variant fibrillar material acquired a thermodynamic stability similar to that of homogenous D76N β2-microglobulin fibrils and significantly higher than the wild-type homogeneous fibrils prepared at neutral pH in the presence of 20% trifluoroethanol. These results suggest that the surface of D76N β2-microglobulin fibrils can favor the transition of the wild-type protein into an amyloid conformation leading to a rapid integration into fibrils. The chaperone crystallin, which is a mild modulator of the lag phase of the variant fibrillogenesis, potently inhibits fibril elongation of the wild-type even once it is absorbed on D76N β2-microglobulin fibrils. PMID:26921323

  7. Developmental Divergence of Sleep-Wake Patterns in Orexin Knockout and Wild-Type Mice

    PubMed Central

    Coleman, Cassandra M.; Johnson, Eric D.; Shaw, Cynthia

    2008-01-01

    Narcolepsy, a disorder characterized by fragmented bouts of sleep and wakefulness during the day and night as well as cataplexy, has been linked in humans and non-human animals to the functional integrity of the orexinergic system. Adult orexin knockout mice and dogs with a mutation of the orexin receptor exhibit symptoms that mirror those seen in narcoleptic humans. As with narcolepsy, infant sleep-wake cycles in humans and rats are highly fragmented, with consolidated bouts of sleep and wakefulness developing gradually. Based on these common features of narcoleptics and infants, we hypothesized that the development of sleep-wake fragmentation in orexin knockout mice would be expressed as a developmental divergence between knockouts and wild-types, with the knockouts lagging behind the wild-types. We tested this hypothesis by recording the sleep-wake patterns of infant orexin knockout and wild-type mice across the first three postnatal weeks. Both knockouts and wild-types exhibited age-dependent, and therefore orexin-independent, quantitative and qualitative changes in sleep-wake patterning. At 3 weeks of age, however, by which time the sleep and wake bouts of the wild-types had consolidated further, the knockouts lagged behind the wild-types and exhibited significantly more bout fragmentation. These findings suggest the possibility that the fragmentation of behavioral states that characterizes narcolepsy in adults reflects reversion back toward the more fragmented sleep-wake patterns that characterize infancy. PMID:17284193

  8. Panitumumab Use in Metastatic Colorectal Cancer and Patterns of KRAS Testing: Results from a Europe-Wide Physician Survey and Medical Records Review

    PubMed Central

    Trojan, Jörg; Mineur, Laurent; Tomášek, Jiří; Rouleau, Etienne; Fabian, Pavel; de Maglio, Giovanna; García-Alfonso, Pilar; Aprile, Giuseppe; Taylor, Aliki; Kafatos, George; Downey, Gerald; Terwey, Jan-Henrik; van Krieken, J. Han

    2015-01-01

    Background From 2008–2013, the European indication for panitumumab required that patients’ tumor KRAS exon 2 mutation status was known prior to starting treatment. To evaluate physician awareness of panitumumab prescribing information and how physicians prescribe panitumumab in patients with metastatic colorectal cancer (mCRC), two European multi-country, cross-sectional, observational studies were initiated in 2012: a physician survey and a medical records review. The first two out of three planned rounds for each study are reported. Methods The primary objective in the physician survey was to estimate the prevalence of KRAS testing, and in the medical records review, it was to evaluate the effect of test results on patterns of panitumumab use. The medical records review study also included a pathologists’ survey. Results In the physician survey, nearly all oncologists (299/301) were aware of the correct panitumumab indication and the need to test patients’ tumor KRAS status before treatment with panitumumab. Nearly all oncologists (283/301) had in the past 6 months of clinical practice administered panitumumab correctly to mCRC patients with wild-type KRAS status. In the medical records review, 97.5% of participating oncologists (77/79) conducted a KRAS test for all of their patients prior to prescribing panitumumab. Four patients (1.3%) did not have tumor KRAS mutation status tested prior to starting panitumumab treatment. Approximately one-quarter of patients (85/306) were treated with panitumumab and concurrent oxaliplatin-containing chemotherapy; of these, 83/85 had confirmed wild-type KRAS status prior to starting panitumumab treatment. All 56 referred laboratories that participated used a Conformité Européenne-marked or otherwise validated KRAS detection method, and nearly all (55/56) participated in a quality assurance scheme. Conclusions There was a high level of knowledge amongst oncologists around panitumumab prescribing information and the

  9. Genomic and Transcriptional Alterations in Lung Adenocarcinoma in Relation to EGFR and KRAS Mutation Status

    PubMed Central

    Planck, Maria; Edlund, Karolina; Botling, Johan; Micke, Patrick; Isaksson, Sofi; Staaf, Johan

    2013-01-01

    Introduction In lung adenocarcinoma, the mutational spectrum is dominated by EGFR and KRAS mutations. Improved knowledge about genomic and transcriptional alterations in and between mutation-defined subgroups may identify genes involved in disease development or progression. Methods Genomic profiles from 457 adenocarcinomas, including 113 EGFR-mutated, 134 KRAS-mutated and 210 EGFR and KRAS-wild type tumors (EGFRwt/KRASwt), and gene expression profiles from 914 adenocarcinomas, including 309 EGFR-mutated, 192 KRAS-mutated, and 413 EGFRwt/KRASwt tumors, were assembled from different repositories. Genomic and transcriptional differences between the three mutational groups were analyzed by both supervised and unsupervised methods. Results EGFR-mutated adenocarcinomas displayed a larger number of copy number alterations and recurrent amplifications, a higher fraction of total loss-of-heterozygosity, higher genomic complexity, and a more distinct expression pattern than EGFR-wild type adenocarcinomas. Several of these differences were also consistent when the three mutational groups were stratified by stage, gender and smoking status. Specific copy number alterations were associated with mutation status, predominantly including regions of gain with the highest frequency in EGFR-mutated tumors. Differential regions included both large and small regions of gain on 1p, 5q34-q35.3, 7p, 7q11.21, 12p12.1, 16p, and 21q, and losses on 6q16.3-q21, 8p, and 9p, with 20-40% frequency differences between the mutational groups. Supervised gene expression analyses identified 96 consistently differentially expressed genes between the mutational groups, and together with unsupervised analyses these analyses highlighted the difficulty in broadly resolving the three mutational groups into distinct transcriptional entities. Conclusions We provide a comprehensive overview of the genomic and transcriptional landscape in lung adenocarcinoma stratified by EGFR and KRAS mutations. Our analyses

  10. Antitumoral Efficacy of the Protease Inhibitor Gabexate Mesilate in Colon Cancer Cells Harbouring KRAS, BRAF and PIK3CA Mutations

    PubMed Central

    Brandi, Giovanni; Tavolari, Simona; De Rosa, Francesco; Di Girolamo, Stefania; Agostini, Valentina; Barbera, Maria Aurelia; Frega, Giorgio; Biasco, Guido

    2012-01-01

    The employment of anti-epidermal growth factor receptor (EGFR) antibodies represents a backbone of the therapeutic options for the treatment of metastatic colorectal cancer (mCRC). However, this therapy is poorly effective or ineffective in unselected patients. Mutations in KRAS, BRAF and PIK3CA genes have recently emerged as the best predictive factors of low/absent response to EGFR-targeted therapy. Due to the need for efficacious treatment options for mCRC patients bearing these mutations, in this short report we examined the antitumoral activity of the protease inhibitor gabexate mesilate, alone and in combination with the anti-EGFR monoclonal antibody cetuximab, in a panel of human CRC cell lines harbouring a different expression pattern of wild-type/mutated KRAS, BRAF and PIK3CA genes. Results obtained showed that gabexate mesilate significantly inhibited the growth, invasive potential and tumour-induced angiogenesis in all the CRC cells employed in this study (including those ones harbouring dual KRAS/PIK3CA or BRAF/PIK3CA mutation), while cetuximab affected these parameters only in CRC cells with KRAS, BRAF and PIK3CA wild-type. Notably, the antitumoral efficacy of gabexate mesilate and cetuximab in combination was found to be not superior than that observed with gabexate mesilate as single agent. Overall, these preliminary findings suggest that gabexate mesilate could represent a promising therapeutic option for mCRC patients, particularly for those harbouring KRAS, BRAF and PIK3CA mutations, either as mono-therapy or in addition to standard chemotherapy regimens. Further studies to better elucidate gabexate mesilate mechanism of action in CRC cells are therefore warranted. PMID:22911782

  11. LYTAK1, a novel TAK1 inhibitor, suppresses KRAS mutant colorectal cancer cell growth in vitro and in vivo.

    PubMed

    Zhou, Jundong; Zheng, Bing; Ji, Jiansong; Shen, Fei; Min, Han; Liu, Biao; Wu, Jinchang; Zhang, Shuyu

    2015-05-01

    KRAS mutation in colorectal cancer (CRC) activates transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) to promote tumor progression. In the current study, we explored the potential effect of LYTAK1, a novel TAK1 inhibitor, against KRAS mutant CRC cells in vitro and in vivo. We found that LYTAK1 dose-dependently inhibited KRAS mutant CRC cell (HT-29 and SW-620 lines) growth, and induced cell cycle G1-S arrest. Further, LYTAK1 activated apoptosis in HT-29 cells and SW-620 cells, and apoptosis inhibitors almost reversed LYTAK1-mediated growth inhibition. While in KRAS wild-type (WT) CRC cell lines (DLD-1 and HCT-116), LYTAK1 had almost no effect on cell growth, cell cycle progression, or cell apoptosis. In KRAS mutant HT-29 cells and SW-260 cells, LYTAK1 blocked TAK1 activation or phosphorylation at Thr-184/187. Activation of nuclear factor κB (NF-κB) in these cells, detected by phosphorylations of p65 and IκB kinase α (IKKα) as well as expression of NF-κB-regulated gene cyclin D1, was significantly inhibited by LYTAK1. Further, LYTAK1 treatment resulted in downregulation of β-catenin and Wnt response gene Axin 2, indicating Wnt inactivation. In vivo, oral LYTAK1 significantly inhibited HT-29 xenograft growth in nude mice. Together, these results show that LYTAK1 inhibits KRAS mutant CRC cell growth both in vitro and in vivo. LYTAK1 might be investigated as a novel agent against CRC with KRAS mutation. PMID:25524577

  12. EGFR and KRAS mutation status in non-small-cell lung cancer occurring in HIV-infected patients.

    PubMed

    Créquit, Perrine; Ruppert, Anne-Marie; Rozensztajn, Nathalie; Gounant, Valérie; Vieira, T; Poulot, Virginie; Antoine, Martine; Chouaid, Christos; Wislez, Marie; Cadranel, Jacques; Lavole, Armelle

    2016-06-01

    Non-small-cell lung cancer (NSCLC) is the most common non-acquired immune deficiency syndrome-related malignancy responsible for death. Mutational status is crucial for choosing treatment of advanced NSCLC, yet no data is available on the frequency of epidermal growth factor receptor (EGFR) and Kirsten ras (KRAS) mutations and their impact on NSCLC in human immunodeficiency virus (HIV)-infected patients (HIV-NSCLC). All consecutive HIV-NSCLC patients diagnosed between June 1996 and August 2013 at two Paris university hospitals were reviewed, with tumor samples analyzed for EGFR and KRAS mutational status. Overall, 63 tumor samples were analyzed out of 73 HIV-NSCLC cases, with 63% of advanced NSCLC. There were 60 non-squamous and nine squamous cell carcinomas, with EGFR and KRAS mutations identified in two (3.3%) and seven (11.5%) tumors, respectively. The proportion of KRAS mutations was 29% if solely the more sensitive molecular techniques were considered. The two patients with advanced adenocarcinoma harboring EGFR mutations exhibited lasting partial response to EGFR-tyrosine kinase inhibitors. Overall survival for patients with advanced NSCLC were >30 months for those with EGFR mutations, <3 months for KRAS mutations (n=2), and the median was 9 months [4.1-14.3] for wild-type (n=34). In multivariate analysis, KRAS mutation and CD4<200 cells/μL were associated with poor prognosis (hazard ratio (HR): 24 [4.1-140.2], p=0.0004; HR: 3.1 [1.3-7.5], p=0.01, respectively). EGFR mutation must be investigated in HIV-NSCLC cases due to its predictive and prognostic impact, whereas KRAS mutation is of poor prognostic value. Clinicians should search for drugs dedicated to this target population. PMID:27133754

  13. The role of antiangiogenic agents in the treatment of patients with advanced colorectal cancer according to K-RAS status.

    PubMed

    García-Alfonso, Pilar; Grande, Enrique; Polo, Eduardo; Afonso, Ruth; Reina, Juan José; Jorge, Mónica; Campos, Juan Manuel; Martínez, Virginia; Angeles, Cristina; Montagut, Clara

    2014-10-01

    Colorectal cancer (CRC) is the fourth most commonly diagnosed cancer worldwide. Recently, it has been found that about 40 % of patients with CRC have mutations in the K-RAS gene. Several clinical trials have showed that patients with metastatic colorectal cancer (mCRC) who present tumour-promoting mutations in signalling pathways involving the epidermal growth factor receptor (EGFR), which includes activating K-RAS mutations, do not respond to anti-EGFR drugs such as panitumumab and cetuximab. Hence, K-RAS status is now considered an important negative predictive factor for response to anti-EGFR drugs. Moreover, K-RAS status seems to have also a prognostic role in CRC, but this fact is somewhat controversial. Activity of antiangiogenic agents seems not to be influenced by K-RAS gene status. Tumour angiogenesis has attracted interest in attempts to improve the management of mCRC. The vascular endothelial growth factor (VEGF) pathway is fundamental to the regulation of angiogenesis, and research has focused on developing agents that selectively target it. In this way, the anti-VEGF antibody bevacizumab in combination with chemotherapy has provided important clinical benefits in terms of response rate, progression-free survival and overall survival to patients with mCRC. Efficacy data of bevacizumab in K-RAS wild-type patients seem to be comparable with the efficacy data observed with anti-EGFR therapies in a cross-trial comparison. Although there is a lack of prospective and randomized data in this setting, the combination of chemotherapy plus antiangiogenic agents could be considered as an effective alternative for the treatment of mCRC with independence of K-RAS gene status. Here, we review the available data we have in the literature of the use of antiangiogenic strategies in the treatment of mCRC nowadays. PMID:24793846

  14. Wild-type and e antigen-minus hepatitis B viruses and course of chronic hepatitis.

    PubMed Central

    Brunetto, M R; Giarin, M M; Oliveri, F; Chiaberge, E; Baldi, M; Alfarano, A; Serra, A; Saracco, G; Verme, G; Will, H

    1991-01-01

    Using an oligonucleotide hybridization assay, we studied the clinical implication of wild-type hepatitis B virus (HBV) and a HBV mutant that is unable to secrete hepatitis B e antigen (HBeAg) because of a translational defect due to a stop codon in the pre-C region in 106 hepatitis B surface antigen-positive patients with chronic hepatitis B. Wild-type HBV was detected in 31 of 42 (73.8%) HBeAg-positive patients, whereas a mixed viral population was present in 10 (23.8%). Significant differences in the severity and outcome of liver disease were not observed in the two groups of patients. However, the emergence of HBeAg-minus HBV in wild-type HBV carriers was associated with an exacerbation of liver disease and was followed by the presence of antibodies against HBeAg (anti-HBe) in serum in 50% of the cases. In 61 of 64 (95.3%) anti-HBe-positive patients, HBeAg-minus HBV was the predominant virus: HBeAg-minus HBV was detected in 42 patients (65.6%), whereas both wild-type and HBeAg-minus HBV were present in 19 (29.7%). HBeAg-minus HBV was associated with a course of hepatitis characterized by flare-ups of liver cell necrosis interspersed with periods of asymptomatic HBV carriage (P less than 0.01). These data support the hypothesis that genetic heterogeneity of HBV significantly influences the course and outcome of chronic hepatitis B. Wild-type HBV secreting HBeAg induces immunologic tolerance and causes chronic infection. HBeAg-minus HBV might be unable to induce chronic infection without the helper function of wild-type HBV, but it appears to be more pathogenic. Once chronic infection is established, HBeAg-minus HBV variants may prevail and displace wild-type virus. Images PMID:2034663

  15. Shoaling and mate choice of wild-type Tanichthys albonubes in the presence of the red fluorescent transgenic conspecifics.

    PubMed

    Jiang, P; Bai, J J; Ye, X; Jian, Q; Chen, M; Chen, X Q

    2011-01-01

    Shoaling and sexual behaviour of wild-type male and female white cloud mountain minnow Tanichthys albonubes were measured in the presence of the red fluorescent transgenic conspecifics under laboratory conditions. Wild-type female test fish showed no significant preference, whereas wild-type male test fish preferred to be near a shoal of red transgenic fish rather than wild-type fish. When placed in a potentially reproductive context, wild-type males had a higher competitive ability over transgenic males; wild-type females spent more time with wild-type males in visually mediated experiments, but wild-type males performed more courtship displays towards transgenic females. These results suggest that the red body colouration does not appear to disturb signal communication between wild-type and transgenic T. albonubes in shoaling behaviour; transgenic males have no mating advantage over wild-type males, but the red body colouration of transgenic females may affect mate choice of wild-type males. PMID:21235550

  16. Effects of Hypoxanthine Substitution in Peptide Nucleic Acids Targeting KRAS2 Oncogenic mRNA Molecules: Theory and Experiment

    PubMed Central

    Sanders, Jeffrey M.; Wampole, Matthew E.; Chen, Chang-Po; Sethi, Dalip; Singh, Amrita; Dupradeau, François-Yves; Wang, Fan; Gray, Brian D.; Thakur, Mathew L.; Wickstrom, Eric

    2013-01-01

    Genetic disorders can arise from single base substitutions in a single gene. A single base substitution for wild type guanine in the twelfth codon of KRAS2 mRNA occurs frequently to initiate lung, pancreatic, and colon cancer. We have observed single base mismatch specificity in radioimaging of mutant KRAS2 mRNA in tumors in mice by in vivo hybridization with radiolabeled peptide nucleic acid (PNA) dodecamers. We hypothesized that multi-mutant specificity could be achieved with a PNA dodecamer incorporating hypoxanthine, which can form Watson-Crick basepairs with adenine, cytosine, thymine, and uracil. Using molecular dynamics simulations and free energy calculations, we show that hypoxanthine substitutions in PNAs are tolerated in KRAS2 RNA-PNA duplexes where wild type guanine is replaced by mutant uracil or adenine in RNA. To validate our predictions, we synthesized PNA dodecamers with hypoxanthine, and then measured the thermal stability of RNA-PNA duplexes. Circular dichroism thermal melting results showed that hypoxanthine-containing PNAs are more stable in duplexes where hypoxanthine-adenine and hypoxanthine-uracil base pairs are formed than single mismatch duplexes or duplexes containing hypoxanthine-guanine opposition. PMID:23972113

  17. The Mutant KRAS Gene Up-regulates BCL-XL Protein via STAT3 to Confer Apoptosis Resistance That Is Reversed by BIM Protein Induction and BCL-XL Antagonism.

    PubMed

    Zaanan, Aziz; Okamoto, Koichi; Kawakami, Hisato; Khazaie, Khashayarsha; Huang, Shengbing; Sinicrope, Frank A

    2015-09-25

    In colorectal cancers with oncogenic GTPase Kras (KRAS) mutations, inhibition of downstream MEK/ERK signaling has shown limited efficacy, in part because of failure to induce a robust apoptotic response. We studied the mechanism of apoptosis resistance in mutant KRAS cells and sought to enhance the efficacy of a KRAS-specific MEK/ERK inhibitor, GDC-0623. GDC-0623 was shown to potently up-regulate BIM expression to a greater extent versus other MEK inhibitors in isogenic KRAS HCT116 and mutant KRAS SW620 colon cancer cells. ERK silencing enhanced BIM up-regulation by GDC-0623 that was due to its loss of phosphorylation at Ser(69), confirmed by a BIM-EL phosphorylation-defective mutant (S69G) that increased protein stability and blocked BIM induction. Despite BIM and BIK induction, the isogenic KRAS mutant versus wild-type cells remained resistant to GDC-0623-induced apoptosis, in part because of up-regulation of BCL-XL. KRAS knockdown by a doxycycline-inducible shRNA attenuated BCL-XL expression. BCL-XL knockdown sensitized KRAS mutant cells to GDC-0623-mediated apoptosis, as did the BH3 mimetic ABT-263. GDC-0623 plus ABT-263 induced a synergistic apoptosis by a mechanism that includes release of BIM from its sequestration by BCL-XL. Furthermore, mutant KRAS activated p-STAT3 (Tyr(705)) in the absence of IL-6 secretion, and STAT3 knockdown reduced BCL-XL mRNA and protein expression. These data suggest that BCL-XL up-regulation by STAT3 contributes to mutant KRAS-mediated apoptosis resistance. Such resistance can be overcome by potent BIM induction and concurrent BCL-XL antagonism to enable a synergistic apoptotic response. PMID:26245900

  18. Proteomic Analysis of Wild-type and Mutant Huntingtin-associated Proteins in Mouse Brains Identifies Unique Interactions and Involvement in Protein Synthesis*

    PubMed Central

    Culver, Brady P.; Savas, Jeffrey N.; Park, Sung K.; Choi, Jeong H.; Zheng, Shuqiu; Zeitlin, Scott O.; Yates, John R.; Tanese, Naoko

    2012-01-01

    Huntington disease is a neurodegenerative disorder caused by a CAG repeat amplification in the gene huntingtin (HTT) that is reflected by a polyglutamine expansion in the Htt protein. Nearly 20 years of research have uncovered roles for Htt in a wide range of cellular processes, and many of these discoveries stemmed from the identification of Htt-interacting proteins. However, no study has employed an impartial and comprehensive strategy to identify proteins that differentially associate with full-length wild-type and mutant Htt in brain tissue, the most relevant sample source to the disease condition. We analyzed Htt affinity-purified complexes from wild-type and HTT mutant juvenile mouse brain from two different biochemical fractions by tandem mass spectrometry. We compared variations in protein spectral counts relative to Htt to identify those proteins that are the most significantly contrasted between wild-type and mutant Htt purifications. Previously unreported Htt interactions with Myo5a, Prkra (PACT), Gnb2l1 (RACK1), Rps6, and Syt2 were confirmed by Western blot analysis. Gene Ontology analysis of these and other Htt-associated proteins revealed a statistically significant enrichment for proteins involved in translation among other categories. Furthermore, Htt co-sedimentation with polysomes in cytoplasmic mouse brain extracts is dependent upon the presence of intact ribosomes. Finally, wild-type or mutant Htt overexpression inhibits cap-dependent translation of a reporter mRNA in an in vitro system. Cumulatively, these data support a new role for Htt in translation and provide impetus for further study into the link between protein synthesis and Huntington disease pathogenesis. PMID:22556411

  19. Variable stress-responsiveness in wild type and domesticated fighting fish.

    PubMed

    Verbeek, Peter; Iwamoto, Toshitaka; Murakami, Noboru

    2008-01-28

    We combined behavioral and physiological measures to compare coping style in wild-type Betta splendens and a domesticated strain selectively bred for sports fighting. We showed previously that the fighter strain is more aggressive than the wild type during experimental conditions that most closely resemble an actual fight. We predicted that compared to the wild type, the fighter strain would show a more proactive coping style, characterized by lesser cortisol and greater sympathetic responses to non-social challenges. We introduced males to an unfamiliar environment and spatial confinement as challenges that may resemble some of those that B. splendens may encounter in its natural habitat. We developed a non-invasive stress assay that enables repeated individual measures of water-borne cortisol. We estimated sympathetic activation through opercular beat rate and recorded the duration of behavioral immobility. We found that exposure to an unfamiliar environment raised cortisol levels in the wild type but not in the fighter strain and that confinement raised cortisol levels in both. In both strains opercular beat rates were significantly reduced during the latter stages of confinement compared to during the early stages. The fighter strain, but not the wild type, adopted a behavioral strategy of immobility from the very beginning of confinement. PMID:17884114

  20. A positively gravitropic mutant mirrors the wild-type protonemal response in the moss Ceratodon purpureus.

    PubMed

    Wagner, T A; Cove, D J; Sack, F D

    1997-06-01

    Wild-type Ceratodon purpureus (Hedw.) Brid. protonemata grow up in the dark by negative gravitropism. When upright wild-type protonemata are reoriented 90 degrees, they temporarily grow down soon after reorientation ("initial reversal") and also prior to cytokinesis ("mitotic reversal"). A positively gravitropic mutant designated wrong- way response (wwr-1) has been isolated by screening ultraviolet light-mutagenized Ceratodon protonemata. Protonemata of wwr-l reoriented from the vertical to the horizontal grow down with kinetics comparable to those of the wild-type. Protonemata of wwr-1 also show initial and mitotic reversals where they temporarily grow up. Thus, the direction of gravitropism, initial reversal, and mitotic reversal are coordinated though each are opposite in wwr-1 compared to the wild-type. Normal plastid zonation is still maintained in dark-grown wwr-1 apical cells, but the plastids are more numerous and plastid sedimentation is more pronounced. In addition, wwr-1 apical cells are wider and the tips greener than in the wild-type. These data suggest that a functional WWR gene product is not necessary for the establishment of some gravitropic polarity, for gravitropism, or for the coordination of the reversals. Thus, the WWR protein may normally transduce information about cell orientation. PMID:11541791

  1. A positively gravitropic mutant mirrors the wild-type protonemal response in the moss Ceratodon purpureus

    NASA Technical Reports Server (NTRS)

    Wagner, T. A.; Cove, D. J.; Sack, F. D.

    1997-01-01

    Wild-type Ceratodon purpureus (Hedw.) Brid. protonemata grow up in the dark by negative gravitropism. When upright wild-type protonemata are reoriented 90 degrees, they temporarily grow down soon after reorientation ("initial reversal") and also prior to cytokinesis ("mitotic reversal"). A positively gravitropic mutant designated wrong- way response (wwr-1) has been isolated by screening ultraviolet light-mutagenized Ceratodon protonemata. Protonemata of wwr-l reoriented from the vertical to the horizontal grow down with kinetics comparable to those of the wild-type. Protonemata of wwr-1 also show initial and mitotic reversals where they temporarily grow up. Thus, the direction of gravitropism, initial reversal, and mitotic reversal are coordinated though each are opposite in wwr-1 compared to the wild-type. Normal plastid zonation is still maintained in dark-grown wwr-1 apical cells, but the plastids are more numerous and plastid sedimentation is more pronounced. In addition, wwr-1 apical cells are wider and the tips greener than in the wild-type. These data suggest that a functional WWR gene product is not necessary for the establishment of some gravitropic polarity, for gravitropism, or for the coordination of the reversals. Thus, the WWR protein may normally transduce information about cell orientation.

  2. Orthotopic transplantation of LH receptor knockout and wild-type ovaries.

    PubMed

    Chudgar, Daksha; Lei, Zhenmin; Rao, Ch V

    2005-10-01

    Luteinizing hormone (LH) receptor knockout animals have an ovarian failure due to an arrest in folliculogenesis at the antral stage. As a result, the animals have an infertility phenotype. The present study was undertaken to determine whether this phenotype could be reversed by orthotopic transplantation of wild-type ovaries. The results revealed that transplanting wild-type ovaries into null animals did not result in resumption of estrus cycles. Although the number of different types of follicles increased, none progressed to ovulation. The serum hormone profiles improved, reflecting the ovarian changes. The wild-type animals with null ovaries also failed to cycle and their ovaries and serum hormone levels were more like null animals with their own ovaries. Although the lack of rescue of null ovaries placed into wild-type animals was predicted, the failure of wild-type ovaries placed in null animals was not, which could be due to chronic exposure of transplanted tissue to high circulating LH levels and also possibly due to altered internal milieu in null animals. These findings may have implications for potential future considerations of grafting normal donor ovaries into women who have an ovarian failure resulting from inactivating LH receptor mutations. PMID:15964032

  3. Discrimination of oligonucleotides of different lengths with a wild-type aerolysin nanopore

    NASA Astrophysics Data System (ADS)

    Cao, Chan; Ying, Yi-Lun; Hu, Zheng-Li; Liao, Dong-Fang; Tian, He; Long, Yi-Tao

    2016-08-01

    Protein nanopores offer an inexpensive, label-free method of analysing single oligonucleotides. The sensitivity of the approach is largely determined by the characteristics of the pore-forming protein employed, and typically relies on nanopores that have been chemically modified or incorporate molecular motors. Effective, high-resolution discrimination of oligonucleotides using wild-type biological nanopores remains difficult to achieve. Here, we show that a wild-type aerolysin nanopore can resolve individual short oligonucleotides that are 2 to 10 bases long. The sensing capabilities are attributed to the geometry of aerolysin and the electrostatic interactions between the nanopore and the oligonucleotides. We also show that the wild-type aerolysin nanopores can distinguish individual oligonucleotides from mixtures and can monitor the stepwise cleavage of oligonucleotides by exonuclease I.

  4. Discrimination of oligonucleotides of different lengths with a wild-type aerolysin nanopore.

    PubMed

    Cao, Chan; Ying, Yi-Lun; Hu, Zheng-Li; Liao, Dong-Fang; Tian, He; Long, Yi-Tao

    2016-08-01

    Protein nanopores offer an inexpensive, label-free method of analysing single oligonucleotides. The sensitivity of the approach is largely determined by the characteristics of the pore-forming protein employed, and typically relies on nanopores that have been chemically modified or incorporate molecular motors. Effective, high-resolution discrimination of oligonucleotides using wild-type biological nanopores remains difficult to achieve. Here, we show that a wild-type aerolysin nanopore can resolve individual short oligonucleotides that are 2 to 10 bases long. The sensing capabilities are attributed to the geometry of aerolysin and the electrostatic interactions between the nanopore and the oligonucleotides. We also show that the wild-type aerolysin nanopores can distinguish individual oligonucleotides from mixtures and can monitor the stepwise cleavage of oligonucleotides by exonuclease I. PMID:27111839

  5. Transport of Wild-Type and Recombinant Nucleopolyhedroviruses by Scavenging and Predatory Arthropods.

    PubMed

    Lee; Fuxa

    2000-05-01

    Wild-type and recombinant nucleopolyhedroviruses (NPVs) were compared in their capability to be transported over limited distances by the predator Podisus maculiventris (Say) and scavengers Sarcophaga bullata (Parker) and Acheta domesticus (Linnaeus) in Trichoplusia ni (Hübner) larvae infesting collards in a greenhouse microcosm. Viruses tested were variants of Autographa californica (Speyer) NPV (AcNPV): wild-type virus (AcNPV.WT), AcNPV expressing a scorpion toxin (AcNPV.AaIT), and AcNPV expressing juvenile hormone esterase (AcJHE.SG). Podisus maculiventris transported AcNPV.WT and S. bullata transported AcNPV.WT and AcNPV.AaIT. Prevalence and transport of AcNPV.WT were greater than those of AcNPV.AaIT and AcJHE.SG, regardless of whether the nontarget organism carriers were present or absent. Podisus maculiventris and S. bullata transported recombinant and wild-type NPVs at a rate of up to 62.5 cm/day, and A. domesticus transported wild-type NPV at 125 cm/day. The infected host insects, T. ni, undoubtedly contributed to viral transport in the current research. In every experiment, both the wild-type and recombinant virus spread to some degree in the plots without predators or scavengers. The relative amounts of NPVs that accumulated in soil, as indicated by bioassay mortality percentages, generally exhibited spatial patterns similar to those of T. ni mortality due to NPV on the collards plants. Thus, the predator and scavengers in the current research demonstrated some capacity to transport wild-type as well as recombinant viruses at significant rates in a greenhouse microcosm. PMID:10882435

  6. Erythritol Metabolism in Wild-Type and Mutant Strains of Schizophyllum commune

    PubMed Central

    Braun, M. L.; Niederpruem, D. J.

    1969-01-01

    Erythritol uptake and metabolism were compared in wild-type mycelium and a dome morphological mutant of the wood-rotting mushroom Schizophyllum commune. Wild-type mycelium utilized glucose, certain hexitols, and pentitols including ribitol, as well as d-erythrose, erythritol, and glycerol as sole carbon sources for growth. The dome mutant utilized all of these compounds except d-erythrose and erythritol. Erythritol- or glycerol-grown wild-type mycelium incorporated erythritol into various cellular constituents, whereas glucose-grown cells lagged considerably before initiation of erythritol uptake. This acquisition was inhibited by cycloheximide. Dome mycelium showed behavior similar to wild-type in uptake of erythritol after growth on glucose or glycerol, except that erythritol was not further catabolized. Enzymes of carbohydrate metabolism were compared in cell extracts of glucose-cultured wild-type mycelium and dome. Enzymes of hexose monophosphate catabolism, nicotinamide adenine dinucleotide (NAD)-dependent sugar alcohol dehydrogenases, and reduced nicotinamide adenine dinucleotide phosphate (NADPH)-coupled erythrose reductase were demonstrated in both. The occurrence of erythrose reductase was unaffected by the nature of the growth carbon source, showed optimal activity at pH 7, and generated NAD phosphate and erythritol as products of the reaction. Glycerol-, d-erythrose-, or erythritol-grown wild-type mycelium contained an NAD-dependent erythritol dehydrogenase absent in glucose cells. Erythritol dehydrogenase activity was optimal at pH 8.8 and produced erythrulose during NAD reduction. Glycerol-growth of dome mycelium induced the erythritol uptake system, but a functional erythritol dehydrogenase could not be demonstrated. Neither wild-type nor dome mycelium produced erythritol dehydrogenase during growth on ribitol. Erythritol metabolism in wild-type cells of S. commune, therefore, involves an NADPH-dependent reduction of d-erythrose to produce erythritol

  7. Kras is Required for Adult Hematopoiesis.

    PubMed

    Damnernsawad, Alisa; Kong, Guangyao; Wen, Zhi; Liu, Yangang; Rajagopalan, Adhithi; You, Xiaona; Wang, Jinyong; Zhou, Yun; Ranheim, Erik A; Luo, Hongbo R; Chang, Qiang; Zhang, Jing

    2016-07-01

    Previous studies indicate that Kras is dispensable for fetal liver hematopoiesis, but its role in adult hematopoiesis remains unclear. Here, we generated a Kras conditional knockout allele to address this question. Deletion of Kras in adult bone marrow (BM) is mediated by Vav-Cre or inducible Mx1-Cre. We find that loss of Kras leads to greatly reduced thrombopoietin (TPO) signaling in hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs), while stem cell factor-evoked ERK1/2 activation is not affected. The compromised TPO signaling is associated with reduced long term- and intermediate-term HSC compartments and a bias toward myeloid differentiation in MPPs. Although granulocyte macrophage colony-stimulating factor (GM-CSF)-evoked ERK1/2 activation is only moderately decreased in Kras(-/-) myeloid progenitors, it is blunted in neutrophils and neutrophil survival is significantly reduced in vitro. At 9-12 months old, Kras conditional knockout mice develop profound hematopoietic defects, including splenomegaly, an expanded neutrophil compartment, and reduced B cell number. In a serial transplantation assay, the reconstitution potential of Kras(-/-) BM cells is greatly compromised, which is attributable to defects in the self-renewal of Kras(-/-) HSCs and defects in differentiated hematopoietic cells. Our results demonstrate that Kras is a major regulator of TPO and GM-CSF signaling in specific populations of hematopoietic cells and its function is required for adult hematopoiesis. Stem Cells 2016;34:1859-1871. PMID:26972179

  8. Cytoplasmic localization of wild-type survivin is associated with constitutive activation of the PI3K/Akt signaling pathway and represents a favorable prognostic factor in patients with acute myeloid leukemia

    PubMed Central

    Serrano-López, Juana; Serrano, Josefina; Figueroa, Vianihuini; Torres-Gomez, Antonio; Tabares, Salvador; Casaño, Javier; Fernandez-Escalada, Noemi; Sánchez-Garcia, Joaquín

    2013-01-01

    Survivin is over-expressed in most hematologic malignancies but the prognostic significance of the subcompartmental distribution of wild-type or splicing variants in acute myeloid leukemia has not been addressed yet. Using western blotting, we assessed the expression of wild-type survivin and survivin splice variants 2B and Delta-Ex3 in nuclear and cytoplasmic protein extracts in samples taken from 105 patients at the time of their diagnosis of acute myeloid leukemia. Given that survivin is a downstream effector of the PI3K/Akt signaling pathway, survivin expression was also correlated with pSer473-Akt. Wild-type survivin and the 2B splice variant were positive in 76.3% and 78.0% of samples in the nucleus, cytoplasm or both, whereas the Delta-Ex3 isoform was only positive in the nucleus in 37.7% of samples. Cytoplasmic localization of wild-type survivin was significantly associated with the presence of high levels of pSer473-Akt (P<0.001). Inhibition of the PI3K/Akt pathway with wortmannin and Ly294002 caused a significant reduction in the expression of cytoplasmic wild-type survivin. The presence of cytoplasmic wild-type survivin and pSer473-Akt was associated with a lower fraction of quiescent leukemia stem cells (P=0.02). The presence of cytoplasmic wild-type survivin and pSer473-Akt were favorable independent prognostic factors. Moreover, the activation of the PI3K/Akt pathway with expression of cytoplasmic wild-type survivin identified a subgroup of acute myeloid leukemia patients with an excellent outcome (overall survival rate of 60.0±21.9% and relapse-free survival of 63.0±13.5%). Our findings suggest that cytoplasmic wild-type survivin is a critical downstream effector of the PI3K/Akt pathway leading to more chemosensitive cells and a more favorable outcome in acute myeloid leukemia. PMID:23812937

  9. KRAS mutation leads to decreased expression of regulator of calcineurin 2, resulting in tumor proliferation in colorectal cancer

    PubMed Central

    Niitsu, H; Hinoi, T; Kawaguchi, Y; Sentani, K; Yuge, R; Kitadai, Y; Sotomaru, Y; Adachi, T; Saito, Y; Miguchi, M; Kochi, M; Sada, H; Shimomura, M; Oue, N; Yasui, W; Ohdan, H

    2016-01-01

    KRAS mutations occur in 30–40% of all cases of human colorectal cancer (CRC). However, to date, specific therapeutic agents against KRAS-mutated CRC have not been developed. We previously described the generation of mouse models of colon cancer with and without Kras mutations (CDX2P-G22Cre;Apcflox/flox; LSL-KrasG12D and CDX2P-G22Cre;Apcflox/flox mice, respectively). Here, the two mouse models were compared to identify candidate genes, which may represent novel therapeutic targets or predictive biomarkers. Differentially expressed genes in tumors from the two mouse models were identified using microarray analysis, and their expression was compared by quantitative reverse transcription–PCR (qRT–PCR) and immunohistochemical analyses in mouse tumors and surgical specimens of human CRC, with or without KRAS mutations, respectively. Furthermore, the functions of candidate genes were studied using human CRC cell lines. Microarray analysis of 34 000 transcripts resulted in the identification of 19 candidate genes. qRT–PCR analysis data showed that four of these candidate genes (Clps, Irx5, Bex1 and Rcan2) exhibited decreased expression in the Kras-mutated mouse model. The expression of the regulator of calcineurin 2 (RCAN2) was also observed to be lower in KRAS-mutated human CRC. Moreover, inhibitory function for cancer cell proliferation dependent on calcineurin was indicated with overexpression and short hairpin RNA knockdown of RCAN2 in human CRC cell lines. KRAS mutations in CRC lead to a decrease in RCAN2 expression, resulting in tumor proliferation due to derepression of calcineurin–nuclear factor of activated T cells (NFAT) signaling. Our findings suggest that calcineurin–NFAT signal may represent a novel molecular target for the treatment of KRAS-mutated CRC. PMID:27526107

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

    PubMed

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

    2016-01-01

    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-Ras4B(WT)-GTP/GDP) catalytic domain, the K-Ras4B(WT)-GTP-GAP complex, and the mutants (K-Ras4B(G12C/G12D/G12V)-GTP/GDP, K-Ras4B(G13D)-GTP/GDP, K-Ras4B(Q61H)-GTP/GDP) and their complexes with GAP. In addition, we simulated 'exchanged' nucleotide states. These comprehensive simulations reveal that in solution K-Ras4B(WT)-GTP exists in two, active and inactive, conformations. Oncogenic mutations differentially elicit an inactive-to-active conformational transition in K-Ras4B-GTP; in K-Ras4B(G12C/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. PMID:26902995

  11. Twist1 Suppresses Senescence Programs and Thereby Accelerates and Maintains Mutant Kras-Induced Lung Tumorigenesis

    PubMed Central

    Thiyagarajan, Saravanan; Das, Sandhya T.; Zabuawala, Tahera; Chen, Joy; Cho, Yoon-Jae; Luong, Richard; Tamayo, Pablo; Salih, Tarek; Aziz, Khaled; Adam, Stacey J.; Vicent, Silvestre; Nielsen, Carsten H.; Withofs, Nadia; Sweet-Cordero, Alejandro; Gambhir, Sanjiv S.; Rudin, Charles M.; Felsher, Dean W.

    2012-01-01

    KRAS mutant lung cancers are generally refractory to chemotherapy as well targeted agents. To date, the identification of drugs to therapeutically inhibit K-RAS have been unsuccessful, suggesting that other approaches are required. We demonstrate in both a novel transgenic mutant Kras lung cancer mouse model and in human lung tumors that the inhibition of Twist1 restores a senescence program inducing the loss of a neoplastic phenotype. The Twist1 gene encodes for a transcription factor that is essential during embryogenesis. Twist1 has been suggested to play an important role during tumor progression. However, there is no in vivo evidence that Twist1 plays a role in autochthonous tumorigenesis. Through two novel transgenic mouse models, we show that Twist1 cooperates with KrasG12D to markedly accelerate lung tumorigenesis by abrogating cellular senescence programs and promoting the progression from benign adenomas to adenocarcinomas. Moreover, the suppression of Twist1 to physiological levels is sufficient to cause Kras mutant lung tumors to undergo senescence and lose their neoplastic features. Finally, we analyzed more than 500 human tumors to demonstrate that TWIST1 is frequently overexpressed in primary human lung tumors. The suppression of TWIST1 in human lung cancer cells also induced cellular senescence. Hence, TWIST1 is a critical regulator of cellular senescence programs, and the suppression of TWIST1 in human tumors may be an effective example of pro-senescence therapy. PMID:22654667

  12. L-Ascorbic acid can abrogate SVCT-2-dependent cetuximab resistance mediated by mutant KRAS in human colon cancer cells.

    PubMed

    Jung, Soo-A; Lee, Dae-Hee; Moon, Jai-Hee; Hong, Seung-Woo; Shin, Jae-Sik; Hwang, Ih Yeon; Shin, Yu Jin; Kim, Jeong Hee; Gong, Eun-Yeung; Kim, Seung-Mi; Lee, Eun Young; Lee, Seul; Kim, Jeong Eun; Kim, Kyu-Pyo; Hong, Yong Sang; Lee, Jung Shin; Jin, Dong-Hoon; Kim, TaeWon; Lee, Wang Jae

    2016-06-01

    Colon cancer patients with mutant KRAS are resistant to cetuximab, an antibody directed against the epidermal growth factor receptor, which is an effective clinical therapy for patients with wild-type KRAS. Numerous combinatorial therapies have been tested to overcome the resistance to cetuximab. However, no combinations have been found that can be used as effective therapeutic strategies. In this study, we demonstrate that L-ascorbic acid partners with cetuximab to induce killing effects, which are influenced by sodium-dependent vitamin C transporter 2 (SVCT-2) in human colon cancer cells with a mutant KRAS. L-Ascorbic acid treatment of human colon cancer cells that express a mutant KRAS differentially and synergistically induced cell death with cetuximab in a SVCT-2-dependent manner. The ectopic expression of SVCT-2 induced sensitivity to L-ascorbic acid treatment in human colon cancer cells that do not express SVCT-2, whereas the knockdown of endogenous SVCT-2 induced resistance to L-ascorbic acid treatment in SVCT-2-positive cells. Moreover, tumor regression via the administration of L-ascorbic acid and cetuximab in mice bearing tumor cell xenografts corresponded to SVCT-2 protein levels. Interestingly, cell death induced by the combination of L-ascorbic acid and cetuximab resulted in both apoptotic and necrotic cell death. These cell death mechanisms were related to a disruption of the ERK pathway and were represented by the impaired activation of RAFs and the activation of the ASK-1-p38 pathway. Taken together, these results suggest that resistance to cetuximab in human colon cancer patients with a mutant KRAS can be bypassed by L-ascorbic acid in an SVCT-2-dependent manner. Furthermore, SVCT-2 in mutant KRAS colon cancer may act as a potent marker for potentiating L-ascorbic acid co-treatment with cetuximab. PMID:27012422

  13. Phosphate uptake in Saccharomyces cerevisiae Hansen wild type and phenotypes exposed to space flight irradiation.

    PubMed

    Berry, D; Volz, P A

    1979-10-01

    Rates of phosphate uptake were approximately twice as great for Saccharomyces cerevisiae single-cell phenotypic isolates exposed to space parameters as for the wild-type ground control. Quantitative determination of 32P was performed by liquid scintillation spectrometry utilizing Cerenkov radiation counting techniques. PMID:395899

  14. Physical and physiological components of the graviresponses of wild-type and mutant Paramecium Tetraurelia.

    PubMed

    Nagel, U; Machemer, H

    2000-03-01

    Wild-type and the morphological mutant kin 241 of Paramecium tetraurelia showed improved orientation away from the centre of gravity (negative gravitaxis) when accelerations were increased from 1 to 7 g. Gravitaxis was more pronounced in the mutant. A correlation between the efficiency of orientation and the applied g value suggests a physical basis for gravitaxis. Transiently enhanced rates of reversal of the swimming direction coincided with transiently enhanced gravitaxis because reversals occurred more often in downward swimmers than in upward swimmers. The results provide evidence of a physiological modulation of gravitaxis by means of the randomizing effect of depolarization-dependent swimming reversals. Gravity bimodally altered propulsion rates of wild-type P. tetraurelia so that sedimentation was partly antagonized in upward and downward swimmers (negative gravikinesis). In the mutant, only increases in propulsion were observed, although the orientation-dependent sensitivity of the gravikinetic response was the same as in the wild-type population. Observed swimming speed and sedimentation rates in the wild-type and mutant cells were linearly related to acceleration, allowing the determination of gravikinesis as a linear (and so far non-saturating) function of gravity. PMID:10683165

  15. Measuring cell wall elasticity on enteroaggregative Escherichia coli wild type and dispersin mutant by AFM

    SciTech Connect

    Beckmann, Melissa; Venkataraman, Sankar; Doktycz, Mitchel John; Nataro, James P; Sullivan, Claretta J; Morrell-Falvey, Jennifer L; Allison, David P

    2006-07-01

    Enteroaggregative Escherichia coli (EAEC) is pathogenic and produces severe diarrhea in humans. A mutant of EAEC that does not produce dispersin, a cell surface protein, is not pathogenic. It has been proposed that dispersin imparts a positive charge to the bacterial cell surface allowing the bacteria to colonize on the negatively charged intestinal mucosa. However, physical properties of the bacterial cell surface, such as rigidity, may be influenced by the presence of dispersin and may contribute to pathogenicity. Using the system developed in our laboratory for mounting and imaging bacterial cells by atomic force microscopy (AFM), in liquid, on gelatin coated mica surfaces, studies were initiated to measure cell surface elasticity. This was carried out in both wild type EAEC, that produces dispersin, and the mutant that does not produce dispersin. This was accomplished using AFM force-distance (FD) spectroscopy on the wild type and mutant grown in liquid or on solid medium. Images in liquid and in air of both the wild-type and mutant grown in liquid and on solid media are presented. This work represents an initial step in efforts to understand the pathogenic role of the dispersin protein in the wild-type bacteria.

  16. COMPARISON OF IN VITRO-CULTURED AND WILD-TYPE PERKINSUS MARINUS I: PATHOGEN VIRULENCE

    EPA Science Inventory

    Perkinsus marinus is a highly contagious pathogen of the eastern oyster Crassostrea virginica. Until recently, transmission studies have employed wild-type parasites isolated directly from infected oysters. Newly developed methods to propagate P. marinus in vitro have led to usin...

  17. ELECTROPHORETIC MOBILITIES OF ESCHERICHIA COLI 0157:H7 AND WILD-TYPE ESCHERICHIA COLI STRAINS

    EPA Science Inventory

    The electrophoretic mobility (EPM) of a number of human-virulent and "wild-type" Escherichia coli strains in phosphate buffered water was measured. The impact of pH, ionic strength, cation type (valence) and concentration, and bacterial strain on the EPM was investigated. Resul...

  18. Sensitive detection of KRAS mutations using enhanced-ice-COLD-PCR mutation enrichment and direct sequence identification.

    PubMed

    How Kit, Alexandre; Mazaleyrat, Nicolas; Daunay, Antoine; Nielsen, Helene Myrtue; Terris, Benoît; Tost, Jörg

    2013-11-01

    A number of methods allowing the detection of low levels of KRAS mutations have been developed in the last years. However, although these methods have become increasingly sensitive, they can rarely identify the mutated base directly without prior knowledge on the mutated base and are often incompatible with a sequencing-based read-out desirable in clinical practice. Here, we present a modified version of the ice-COLD-PCR assay called Enhanced-ice-COLD-PCR (E-ice-COLD-PCR) for KRAS mutation detection and identification, which allows the enrichment of the six most frequent KRAS mutations. The method is based on a nonextendable chemically modified blocker sequence, complementary to the wild-type (WT) sequence leading to the enrichment of mutated sequences. This assay permits the reliable detection of down to 0.1% mutated sequences in a WT background. A single genotyping assay of the amplification product by pyrosequencing directly following the E-ice-COLD-PCR is performed to identify the mutated base. This developed two-step method is rapid and cost-effective, and requires only a small amount of starting material permitting the sensitive detection and sequence identification of KRAS mutations within 3 hr. This method is applied in the current study to clinical colorectal cancer samples and enables detection of mutations in samples, which appear as WT using standard detection technologies. PMID:24038839

  19. Nutlin-3a: A Potential Therapeutic Opportunity for TP53 Wild-Type Ovarian Carcinomas

    PubMed Central

    Tsang, Yvonne T. M.; Mullany, Lisa K.; Zu, Zhifei; Richards, JoAnne S.; Gershenson, David M.; Wong, Kwong-Kwok

    2015-01-01

    Epithelial ovarian cancer is a diverse molecular and clinical disease, yet standard treatment is the same for all subtypes. TP53 mutations represent a node of divergence in epithelial ovarian cancer histologic subtypes and may represent a therapeutic opportunity in subtypes expressing wild type, including most low-grade ovarian serous carcinomas, ovarian clear cell carcinomas and ovarian endometrioid carcinomas, which represent approximately 25% of all epithelial ovarian cancer. We therefore sought to investigate Nutlin-3a—a therapeutic which inhibits MDM2, activates wild-type p53, and induces apoptosis—as a therapeutic compound for TP53 wild-type ovarian carcinomas. Fifteen epithelial ovarian cancer cell lines of varying histologic subtypes were treated with Nutlin-3a with determination of IC50 values. Western Blot (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) analyses quantified MDM2, p53, and p21 expression after Nutlin-3a treatment. DNA from 15 cell lines was then sequenced for TP53 mutations in exons 2-11 including intron-exon boundaries. Responses to Nutlin-3a were dependent upon TP53 mutation status. By qRT-PCR and WB, levels of MDM2 and p21 were upregulated in wild-type TP53 sensitive cell lines, and p21 induction was reduced or absent in mutant cell lines. Annexin V assays demonstrated apoptosis in sensitive cell lines treated with Nutlin-3a. Thus, Nutlin-3a could be a potential therapeutic agent for ovarian carcinomas expressing wild-type TP53 and warrants further investigation. PMID:26248031

  20. Nutlin-3a: A Potential Therapeutic Opportunity for TP53 Wild-Type Ovarian Carcinomas.

    PubMed

    Crane, Erin K; Kwan, Suet-Yan; Izaguirre, Daisy I; Tsang, Yvonne T M; Mullany, Lisa K; Zu, Zhifei; Richards, JoAnne S; Gershenson, David M; Wong, Kwong-Kwok

    2015-01-01

    Epithelial ovarian cancer is a diverse molecular and clinical disease, yet standard treatment is the same for all subtypes. TP53 mutations represent a node of divergence in epithelial ovarian cancer histologic subtypes and may represent a therapeutic opportunity in subtypes expressing wild type, including most low-grade ovarian serous carcinomas, ovarian clear cell carcinomas and ovarian endometrioid carcinomas, which represent approximately 25% of all epithelial ovarian cancer. We therefore sought to investigate Nutlin-3a--a therapeutic which inhibits MDM2, activates wild-type p53, and induces apoptosis--as a therapeutic compound for TP53 wild-type ovarian carcinomas. Fifteen epithelial ovarian cancer cell lines of varying histologic subtypes were treated with Nutlin-3a with determination of IC50 values. Western Blot (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) analyses quantified MDM2, p53, and p21 expression after Nutlin-3a treatment. DNA from 15 cell lines was then sequenced for TP53 mutations in exons 2-11 including intron-exon boundaries. Responses to Nutlin-3a were dependent upon TP53 mutation status. By qRT-PCR and WB, levels of MDM2 and p21 were upregulated in wild-type TP53 sensitive cell lines, and p21 induction was reduced or absent in mutant cell lines. Annexin V assays demonstrated apoptosis in sensitive cell lines treated with Nutlin-3a. Thus, Nutlin-3a could be a potential therapeutic agent for ovarian carcinomas expressing wild-type TP53 and warrants further investigation. PMID:26248031

  1. The combination of tetraiodothyroacetic acid and cetuximab inhibits cell proliferation in colorectal cancers with different K-ras status.

    PubMed

    Lee, Yee-Shin; Chin, Yu-Tang; Yang, Yu-Chen S H; Wei, Po-Li; Wu, Han-Chung; Shih, Ai; Lu, Yueh-Tong; Pedersen, Jens Z; Incerpi, Sandra; Liu, Leroy F; Lin, Hung-Yun; Davis, Paul J

    2016-07-01

    Thyroid hormone induces cancer cell proliferation through its cell surface receptor integrin αvβ3. Acting via integrin αvβ3, the deaminated T4 analog tetraiodothyroacetic acid (tetrac), and its nanoparticle formulation nano-diamino-tetrac (NDAT) could inhibit cell proliferation and xenograft growth. In this study, we investigated the T4 effects on proliferation in colorectal cancer cell lines based on the proliferation marker expressions at both mRNA and protein levels. The effects of tetrac/NDAT, the monoclonal anti-EGFR antibody cetuximab, and their combinations on colorectal cancer cell proliferation were examined according to the relevant gene expression profiles and cell count analysis. The results showed that T4 significantly enhanced PCNA, Cyclin D1 and c-Myc levels in both K-ras wild type HT-29 and mutant HCT 116 cells. In HCT 116 cells, the combination of NDAT and cetuximab significantly suppressed the mRNA expressions of proliferative genes PCNA, Cyclin D1, c-Myc and RRM2 raised by T4 compared to cetuximab alone. In addition, T4-suppressed mRNA expressions of pro-apoptotic genes p53 and RRM2B could be significantly elevated by the combination of NDAT and cetuximab compared to cetuximab alone. In the K-ras mutant HCT 116 cells, but not in the K-ras wild type COLO 205 cells, the combinations of tetrac/NDAT and cetuximab significantly reduced cell proliferation compared to cetuximab alone. In conclusion, T4 promoted colorectal cancer cell proliferation which could be repressed by tetrac and NDAT. The combinations of tetrac/NDAT and cetuximab potentiated cetuximab actions in K-ras mutant colorectal cancer cells. PMID:26980146

  2. Modulation of EZH2 Expression by MEK-ERK or PI3K-AKT Signaling in Lung Cancer Is Dictated by Different KRAS Oncogene Mutations.

    PubMed

    Riquelme, Erick; Behrens, Carmen; Lin, Heather Y; Simon, George; Papadimitrakopoulou, Vassiliki; Izzo, Julie; Moran, Cesar; Kalhor, Neda; Lee, J Jack; Minna, John D; Wistuba, Ignacio I

    2016-02-01

    EZH2 overexpression promotes cancer by increasing histone methylation to silence tumor suppressor genes, but how EZH2 levels become elevated in cancer is not understood. In this study, we investigated the mechanisms by which EZH2 expression is regulated in non-small cell lung carcinoma cells by oncogenic KRAS. In cells harboring KRAS(G12C) and KRAS(G12D) mutations, EZH2 expression was modulated by MEK-ERK and PI3K/AKT signaling, respectively. Accordingly, MEK-ERK depletion decreased EZH2 expression in cells harboring the KRAS(G12C) mutation, whereas PI3K/AKT depletion decreased EZH2 expression, EZH2 phosphorylation, and STAT3 activity in KRAS(G12D)-mutant cell lines. Combined inhibition of EZH2 and MEK-ERK or PI3K/AKT increased the sensitivity of cells with specific KRAS mutations to MEK-ERK and PI3K/AKT-targeted therapies. Our work defines EZH2 as a downstream effector of KRAS signaling and offers a rationale for combining EZH2 inhibitory strategies with MEK-ERK- or PI3K/AKT-targeted therapies to treat lung cancer patients, as stratified into distinct treatment groups based on specific KRAS mutations. PMID:26676756

  3. Prognostic impact of KRAS mutant type and MET amplification in metastatic and recurrent gastric cancer patients treated with first-line S-1 plus cisplatin chemotherapy

    PubMed Central

    Matsusaka, Satoshi; Kobunai, Takashi; Yamamoto, Noriko; Chin, Keisho; Ogura, Mariko; Tanaka, Gotaro; Matsuoka, Kazuaki; Ishikawa, Yuichi; Mizunuma, Nobuyuki; Yamaguchi, Toshiharu

    2016-01-01

    Receptor tyrosine kinase (RTK)-related genes, including HER2, EGFR, MET, FGFR2 and KRAS, are target molecules that are clinically beneficial in gastric cancer (GC). We investigated the correlation between RTK-related genes and the curative effect of first-line S-1 plus cisplatin (SP) combination chemotherapy in metastatic and recurrent GC. We enrolled 150 patients with histopathologically confirmed metastatic and recurrent GC treated with SP. KRAS mutation was detected using direct sequencing. DNA copy number was measured by real-time PCR. Formalin-fixed paraffin-embedded specimens were examined immunohistochemically for HER2, EGFR, FGFR2 and MET. Among 144 patients, KRAS mutation was detected in five (3.5%) at codon 12 and one (0.7%) at codon 13. FGFR2, EGFR, HER2, MET and KRAS gene amplification was suggested in 4.4%, 5.9%, 9%, 3.7% and 10.3% of patients, respectively. KRAS mutation, but not KRAS amplification, was associated with significantly shorter overall and progression-free survival. MET membranous overexpression was associated with a significantly higher tumor response. MET amplification was associated with significantly shorter overall survival. We show for the first time that KRAS mutation and MET amplification are promising predictive markers in metastatic and recurrent GC patients treated with SP. KRAS status may be a useful prognostic marker in patients treated with SP. PMID:27014419

  4. Differential morphology and transcriptome profile between the incompletely fused carpels ovary and its wild-type in maize.

    PubMed

    Li, Hongping; Wu, Yufeng; Zhao, Yali; Hu, Xiuli; Chang, Jianfeng; Wang, Qun; Dong, Pengfei; Zhang, Moubiao; Li, Chaohai

    2016-01-01

    We have isolated a new mutation in maize, incompletely fused carpels (ifc), which results in an open stylar canal on the ovary and an incomplete pericarp at the top of the kernel. The maize ovary derives from the fusion of three carpels; however, the molecular networks regulating maize carpel fusion remain largely unclear. In this study, RNA sequencing (RNA-seq) was performed on wild-type (WT) and ifc ovaries that were collected after carpel fusion defects could be morphologically distinguished. In total, 877 differentially expressed genes were identified. Functional analysis revealed overexpression of genes related to "DNA binding", "transcription regulation", "hormones", and "stress responses". Among the 88 differentially expressed transcription factor (TF) genes, five showed a high degree of conservation (77.7-88.0% amino acid identity) of their conserved domains with genes associated with carpel fusion deficiency in Arabidopsis thaliana, suggesting that these five genes might control carpel fusion in maize. In addition, 30 genes encoding components of hormone synthesis and signaling pathways were differentially expressed between ifc and WT ovaries, indicating complex hormonal regulation during carpel fusion. These results help elucidate the underlying mechanisms that regulate carpel fusion, supporting the functional analysis of genes involved in producing this phenotype. PMID:27587343

  5. BCAT1 promotes cell proliferation through amino acid catabolism in gliomas carrying wild-type IDH1

    PubMed Central

    Park, Yoon Jung; Wang, Wei; Schlotter, Magdalena; Lindroth, Anders M; Pleier, Sabrina V; Bai, Alfa H C; Karra, Daniela; Piro, Rosario M; Felsberg, Jörg; Addington, Adele; Lemke, Dieter; Weibrecht, Irene; Hovestadt, Volker; Rolli, Claudio G; Campos, Benito; Turcan, Sevin; Sturm, Dominik; Witt, Hendrik; Chan, Timothy A; Herold-Mende, Christel; Kemkemer, Ralf; König, Rainer; Schmidt, Kathrin; Hull, William-Edmund; Pfister, Stefan M; Jugold, Manfred; Hutson, Susan M; Plass, Christoph; Okun, Jürgen G; Reifenberger, Guido; Lichter, Peter; Radlwimmer, Bernhard

    2016-01-01

    Here we show that glioblastoma express high levels of branched-chain amino acid transaminase 1 (BCAT1), the enzyme that initiates the catabolism of branched-chain amino acids (BCAAs). Expression of BCAT1 was exclusive to tumors carrying wild-type isocitrate dehydrogenase 1 (IDH1) and IDH2 genes and was highly correlated with methylation patterns in the BCAT1 promoter region. BCAT1 expression was dependent on the concentration of α-ketoglutarate substrate in glioma cell lines and could be suppressed by ectopic overexpression of mutant IDH1 in immortalized human astrocytes, providing a link between IDH1 function and BCAT1 expression. Suppression of BCAT1 in glioma cell lines blocked the excretion of glutamate and led to reduced proliferation and invasiveness in vitro, as well as significant decreases in tumor growth in a glioblastoma xenograft model. These findings suggest a central role for BCAT1 in glioma pathogenesis, making BCAT1 and BCAA metabolism attractive targets for the development of targeted therapeutic approaches to treat patients with glioblastoma. PMID:23793099

  6. Sex and Immunogen-Specific Benefits of Immunotherapy Targeting Islet Amyloid Polypeptide in Transgenic and Wild-Type Mice

    PubMed Central

    Krishnamurthy, Pavan K.; Rajamohamedsait, Hameetha B.; Gonzalez, Veronica; Rajamohamedsait, Wajitha J.; Ahmed, Nawal; Krishnaswamy, Senthilkumar; Sigurdsson, Einar M.

    2016-01-01

    Type 2 diabetes mellitus is characterized by the deposition of islet amyloid polypeptide (IAPP) as amyloid in islets, a process thought to be toxic to β-cells. To determine the feasibility of targeting these aggregates therapeutically, we vaccinated transgenic (Tg) mice that overexpress human IAPP and were fed a high-fat diet to promote their diabetic phenotype. Our findings indicate that prophylactic vaccination with IAPP and its derivative IAPP7-19-TT, protects wild-type female mice, but not males, from obesity-induced early mortality, and the derivative showed a strong trend for prolonging the lifespan of Tg females but not males. Furthermore, IAPP7-19-TT-immunized Tg females cleared a glucose bolus more efficiently than controls, while IAPP-immunized Tg females showed an impaired ability to clear a glucose bolus compared to their adjuvant injected Tg controls. Interestingly, IAPP or IAPP7-19-TT treatments had no effect on glucose clearance in Tg males. Overall, these beneficial effects of IAPP targeted immunization depend on Tg status, sex, and immunogen. Hence, future studies in this field should carefully consider these variables that clearly affect the therapeutic outcome. In conclusion, IAPP targeting immunotherapy may have benefits in patients with type 2 diabetes. PMID:27379014

  7. Differential morphology and transcriptome profile between the incompletely fused carpels ovary and its wild-type in maize

    PubMed Central

    Li, Hongping; Wu, Yufeng; Zhao, Yali; Hu, Xiuli; Chang, Jianfeng; Wang, Qun; Dong, Pengfei; Zhang, Moubiao; Li, Chaohai

    2016-01-01

    We have isolated a new mutation in maize, incompletely fused carpels (ifc), which results in an open stylar canal on the ovary and an incomplete pericarp at the top of the kernel. The maize ovary derives from the fusion of three carpels; however, the molecular networks regulating maize carpel fusion remain largely unclear. In this study, RNA sequencing (RNA-seq) was performed on wild-type (WT) and ifc ovaries that were collected after carpel fusion defects could be morphologically distinguished. In total, 877 differentially expressed genes were identified. Functional analysis revealed overexpression of genes related to “DNA binding”, “transcription regulation”, “hormones”, and “stress responses”. Among the 88 differentially expressed transcription factor (TF) genes, five showed a high degree of conservation (77.7–88.0% amino acid identity) of their conserved domains with genes associated with carpel fusion deficiency in Arabidopsis thaliana, suggesting that these five genes might control carpel fusion in maize. In addition, 30 genes encoding components of hormone synthesis and signaling pathways were differentially expressed between ifc and WT ovaries, indicating complex hormonal regulation during carpel fusion. These results help elucidate the underlying mechanisms that regulate carpel fusion, supporting the functional analysis of genes involved in producing this phenotype. PMID:27587343

  8. Spontaneous generation of rapidly transmissible prions in transgenic mice expressing wild-type bank vole prion protein.

    PubMed

    Watts, Joel C; Giles, Kurt; Stöhr, Jan; Oehler, Abby; Bhardwaj, Sumita; Grillo, Sunny K; Patel, Smita; DeArmond, Stephen J; Prusiner, Stanley B

    2012-02-28

    Currently, there are no animal models of the most common human prion disorder, sporadic Creutzfeldt-Jakob disease (CJD), in which prions are formed spontaneously from wild-type (WT) prion protein (PrP). Interestingly, bank voles (BV) exhibit an unprecedented promiscuity for diverse prion isolates, arguing that bank vole PrP (BVPrP) may be inherently prone to adopting misfolded conformations. Therefore, we constructed transgenic (Tg) mice expressing WT BVPrP. Tg(BVPrP) mice developed spontaneous CNS dysfunction between 108 and 340 d of age and recapitulated the hallmarks of prion disease, including spongiform degeneration, pronounced astrogliosis, and deposition of alternatively folded PrP in the brain. Brain homogenates of ill Tg(BVPrP) mice transmitted disease to Tg(BVPrP) mice in ∼35 d, to Tg mice overexpressing mouse PrP in under 100 d, and to WT mice in ∼185 d. Our studies demonstrate experimentally that WT PrP can spontaneously form infectious prions in vivo. Thus, Tg(BVPrP) mice may be useful for studying the spontaneous formation of prions, and thus may provide insight into the etiology of sporadic CJD. PMID:22331873

  9. Human wild-type full-length tau accumulation disrupts mitochondrial dynamics and the functions via increasing mitofusins

    PubMed Central

    Li, Xia-Chun; Hu, Yu; Wang, Zhi-hao; Luo, Yu; Zhang, Yao; Liu, Xiu-Ping; Feng, Qiong; Wang, Qun; Ye, Keqiang; Liu, Gong-Ping; Wang, Jian-Zhi

    2016-01-01

    Intracellular accumulation of tau protein is hallmark of sporadic Alzheimer’s disease (AD), however, the cellular mechanism whereby tau accumulation causes neurodegeneration is poorly understood. Here we report that overexpression of human wild-type full-length tau (termed htau) disrupted mitochondrial dynamics by enhancing fusion and induced their perinuclear accumulation in HEK293 cells and rat primary hippocampal neurons. The htau accumulation at later stage inhibited mitochondrial functions shown by the decreased ATP level, the ratio of ATP/ADP and complex I activity. Simultaneously, the cell viability was decreased with retraction of the cellular/neuronal processes. Further studies demonstrated that htau accumulation increased fusion proteins, including OPA1 and mitofusins (Mfn1, Mfn2) and reduced the ubiquitination of Mfn2. Downregulation of the mitofusins by shRNA to ~45% or ~52% of the control levels attenuated the htau-enhanced mitochondrial fusion and restored the functions, while downregulation of OPA1 to ~50% of the control level did not show rescue effects. Finally, abnormal mitochondrial accumulation and dysfunction were also observed in the brains of htau transgenic mice. Taken together, our data demonstrate that htau accumulation decreases cell viability and causes degeneration via enhancing mitofusin-associated mitochondrial fusion, which provides new insights into the molecular mechanisms underlying tauopathies. PMID:27099072

  10. Differential Transcriptome Networks between IDO1-Knockout and Wild-Type Mice in Brain Microglia and Macrophages

    PubMed Central

    Gonzalez-Pena, Dianelys; Nixon, Scott E.; Southey, Bruce R.; Lawson, Marcus A.; McCusker, Robert H.; Hernandez, Alvaro G.; Dantzer, Robert; Kelley, Keith W.; Rodriguez-Zas, Sandra L.

    2016-01-01

    Microglia in the brain and macrophages in peripheral organs are cell types responsible for immune response to challenges. Indoleamine 2,3-dioxygenase 1 (IDO1) is an immunomodulatory enzyme of the tryptophan pathway that is expressed in the brain. The higher activity of IDO1 in response to immune challenge has been implicated in behavioral disorders. The impact of IDO1 depletion on the microglia transcriptome has not been studied. An investigation of the transcript networks in the brain microglia from IDO1-knockout (IDO1-KO) mice was undertaken, relative to peripheral macrophages and to wild-type (WT) mice under unchallenged conditions. Over 105 transcript isoforms were differentially expressed between WT and IDO1-KO within cell type. Within microglia, Saa3 and Irg1 were over-expressed in IDO1-KO relative to WT. Within macrophages, Csf3 and Sele were over-expressed in IDO1-KO relative to WT. Among the genes differentially expressed between strains, enriched biological processes included ion homeostasis and ensheathment of neurons within microglia, and cytokine and chemokine expression within macrophages. Over 11,110 transcript isoforms were differentially expressed between microglia and macrophages and of these, over 10,800 transcripts overlapped between strains. Enriched biological processes among the genes over- and under-expressed in microglia relative to macrophages included cell adhesion and apoptosis, respectively. Detected only in microglia or macrophages were 421 and 43 transcript isoforms, respectively. Alternative splicing between cell types based on differential transcript isoform abundance was detected in 210 genes including Phf11d, H2afy, and Abr. Across strains, networks depicted a predominance of genes under-expressed in microglia relative to macrophages that may be a precursor for the different response of both cell types to challenges. The detected transcriptome differences enhance the understanding of the role of IDO1 in the microglia transcriptome

  11. ARID1A Alterations Are Associated with FGFR3-Wild Type, Poor-Prognosis, Urothelial Bladder Tumors

    PubMed Central

    Balbás-Martínez, Cristina; Rodríguez-Pinilla, María; Casanova, Ariel; Domínguez, Orlando; Pisano, David G.; Gómez, Gonzalo; Lloreta, Josep; Lorente, José A.; Malats, Núria; Real, Francisco X.

    2013-01-01

    Urothelial bladder cancer (UBC) is heterogeneous at the clinical, pathological, genetic, and epigenetic levels. Exome sequencing has identified ARID1A as a novel tumor suppressor gene coding for a chromatin remodeling protein that is mutated in UBC. Here, we assess ARID1A alterations in two series of patients with UBC. In the first tumor series, we analyze exons 2–20 in 52 primary UBC and find that all mutant tumors belong to the aggressive UBC phenotype (high grade non-muscle invasive and muscle invasive tumors) (P = 0.05). In a second series (n = 84), we assess ARID1A expression using immunohistochemistry, a surrogate for mutation analysis, and find that loss of expression increases with higher stage/grade, it is inversely associated with FGFR3 overexpression (P = 0.03) but it is not correlated with p53 overexpression (P = 0.30). We also analyzed the expression of cytokeratins in the same set of tumor and find, using unsupervised clustering, that tumors with ARID1A loss of expression are generally KRT5/6-low. In this patient series, loss of ARID1A expression is also associated with worse prognosis, likely reflecting the higher prevalence of losses found in tumors of higher stage and grade. The independent findings in these two sets of patients strongly support the notion that ARID1A inactivation is a key player in bladder carcinogenesis occurring predominantly in FGFR3 wild type tumors. PMID:23650517

  12. Cetuximab treatment for metastatic colorectal cancer with KRAS p.G13D mutations improves progression-free survival

    PubMed Central

    OSUMI, HIROKI; SHINOZAKI, EIJI; OSAKO, MASAHIKO; KAWAZOE, YOSHIMASA; OBA, MASARU; MISAKA, TAKAHARU; GOTO, TAKASHI; KAMO, HITOMI; SUENAGA, MITSUKUNI; KUMEKAWA, YOSUKE; OGURA, MARIKO; OZAKA, MASATO; MATSUSAKA, SATOSHI; CHIN, KEISHO; HATAKE, KIYOHIKO; MIZUNUMA, NOBUYUKI

    2015-01-01

    A number of previous studies have reported that 30–50% of patients with colorectal cancer (CRC) harbor Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations, which is a major predictive biomarker of resistance to epidermal growth factor (EGFR)-targeted therapy. Treatment with an anti-EGFR inhibitor is recommended for patients with KRAS wild-type metastatic colorectal cancer (mCRC). A recent retrospective study of cetuximab reported that patients with KRAS p.G13D mutations had better outcomes compared with those with other mutations. The aim of this retrospective study was to assess the prevalence of KRAS p.G13D mutations and evaluate the effectiveness of cetuximab in mCRC patients with KRAS p.G13D or other KRAS mutations. We reviewed the clinical records of 98 mCRC patients with KRAS mutations who were treated between August, 2004 and January, 2011 in four hospitals located in Tokyo and Kyushu Island. We also investigated KRAS mutation subtypes and patient characteristics. In the patients who received cetuximab, univariate and multivariate analyses were performed to assess the effect of KRAS p.G13D mutations on progression-free survival (PFS) and overall survival (OS). Of the 98 patients, 23 (23.5%) had KRAS p.G13D-mutated tumors, whereas 75 (76.5%) had tumors harboring other mutations. Of the 31 patients who received cetuximab, 9 (29.0%) had KRAS p.G13D mutations and 22 (71.0%) had other mutations. There were no significant differences in age, gender, primary site, pathological type, history of chemotherapy, or the combined use of irinotecan between either of the patient subgroups. The univariate analysis revealed no significant difference in PFS or OS between the patients with KRAS p.G13D mutations and those with other mutations (median PFS, 4.5 vs. 2.8 months, respectively; P=0.65; and median OS, 15.3 vs. 8.9 months, respectively; P=0.51). However, the multivariate analysis revealed a trend toward better PFS among patients harboring p.G13D mutations (PFS

  13. Common and Rare EGFR and KRAS Mutations in a Dutch Non-Small-Cell Lung Cancer Population and Their Clinical Outcome

    PubMed Central

    Kerner, Gerald S. M. A.; Schuuring, Ed; Sietsma, Johanna; Hiltermann, Thijo J. N.; Pieterman, Remge M.; de Leede, Gerard P. J.; van Putten, John W. G.; Liesker, Jeroen; Renkema, Tineke E. J.; van Hengel, Peter; Platteel, Inge; Timens, Wim; Groen, Harry J. M.

    2013-01-01

    Introduction In randomly assigned studies with EGFR TKI only a minor proportion of patients with NSCLC have genetically profiled biopsies. Guidelines provide evidence to perform EGFR and KRAS mutation analysis in non-squamous NSCLC. We explored tumor biopsy quality offered for mutation testing, different mutations distribution, and outcome with EGFR TKI. Patient and Methods Clinical data from 8 regional hospitals were studied for patient and tumor characteristics, treatment and overall survival. Biopsies sent to the central laboratory were evaluated for DNA quality and subsequently analyzed for mutations in exons 18–21 of EGFR and exon 2 of KRAS by bidirectional sequence analysis. Results Tumors from 442 subsequent patients were analyzed. For 74 patients (17%) tumors were unsuitable for mutation analysis. Thirty-eight patients (10.9%) had EGFR mutations with 79% known activating mutations. One hundred eight patients (30%) had functional KRAS mutations. The mutation spectrum was comparable to the Cosmic database. Following treatment in the first or second line with EGFR TKI median overall survival for patients with EGFR (n = 14), KRAS (n = 14) mutations and wild type EGFR/KRAS (n = 31) was not reached, 20 and 9 months, respectively. Conclusion One out of every 6 tumor samples was inadequate for mutation analysis. Patients with EGFR activating mutations treated with EGFR-TKI have the longest survival. PMID:23922984

  14. Kras activation in p53-deficient myoblasts results in high-grade sarcoma formation with impaired myogenic differentiation

    PubMed Central

    McKinnon, Timothy; Venier, Rosemarie; Dickson, Brendan C.; Kabaroff, Leah; Alkema, Manon; Chen, Li; Shern, Jack F.; Yohe, Marielle E.; Khan, Javed; Gladdy, Rebecca A.

    2015-01-01

    While genomic studies have improved our ability to classify sarcomas, the molecular mechanisms involved in the formation and progression of many sarcoma subtypes are unknown. To better understand developmental origins and genetic drivers involved in rhabdomyosarcomagenesis, we describe a novel sarcoma model system employing primary murine p53-deficient myoblasts that were isolated and lentivirally transduced with KrasG12D. Myoblast cell lines were characterized and subjected to proliferation, anchorage-independent growth and differentiation assays to assess the effects of transgenic KrasG12D expression. KrasG12D overexpression transformed p53−/− myoblasts as demonstrated by an increased anchorage-independent growth. Induction of differentiation in parental myoblasts resulted in activation of key myogenic regulators. In contrast, Kras-transduced myoblasts had impaired terminal differentiation. p53−/− myoblasts transformed by KrasG12D overexpression resulted in rapid, reproducible tumor formation following orthotopic injection into syngeneic host hindlimbs. Pathological analysis revealed high-grade sarcomas with myogenic differentiation based on the expression of muscle-specific markers, such as Myod1 and Myog. Gene expression patterns of murine sarcomas shared biological pathways with RMS gene sets as determined by gene set enrichment analysis (GSEA) and were 61% similar to human RMS as determined by metagene analysis. Thus, our novel model system is an effective means to model high-grade sarcomas along the RMS spectrum. PMID:25992772

  15. Fusarium spp. Associated with Field-Grown Grain of Near-Isogenic Low Lignin and Wild-Type Sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium spp. associated with field-grown grain of near-isogenic low lignin and wild-type sorghum. Deanna Funnell-Harris and Jeff Pedersen, USDA-ARS, Lincoln, NE Previous studies indicated that low lignin brown midrib (bmr) sorghum may be more resistant to Fusarium spp. than wild-type and that phen...

  16. Mating success of wild type and sepia mutants Drosophila melanogaster in different choice.

    PubMed

    Stanić, Snezana; Pavković-Lucic, Sofija

    2005-01-01

    Mating behaviour of red-eyed (wt) and brown-eyed (sepia) Drosophila melanogaster was studied under light conditions. Mating success was directly observed in mating vials and techniques usually applied in the studies of sexual selection ("female choice" and "multiple choice"). The comparison of sexual activity of mutant and wild types clearly indicates that they are not equally successful in matings. Sepia eye colour mutation decreases sexual activity of Drosophila melanogaster males, influences the preference ability of females and decreases the number of progeny from homogamic mating of the se x se type, as well as from heterogamic copulations in which sepia females take part. Non-random mating of wild type males and sepia females (in "multiple-choice" situation), with genetically and phenotypically different individuals, could be another mechanism for conservation of genetic polymorphism in natural populations. PMID:16440285

  17. Cytochemical Analysis of Pollen Development in Wild-Type Arabidopsis and a Male-Sterile Mutant.

    PubMed Central

    Regan, SM; Moffatt, BA

    1990-01-01

    Microsporogenesis has been examined in wild-type Arabidopsis thaliana and the nuclear male-sterile mutant BM3 by cytochemical staining. The mutant lacks adenine phosphoribosyltransferase, an enzyme of the purine salvage pathway that converts adenine to AMP. Pollen development in the mutant began to diverge from wild type just after meiosis, as the tetrads of microspores were released from their callose walls. The first indication of abnormal pollen development in the mutant was a darker staining of the microspore wall due to an incomplete synthesis of the intine. Vacuole formation was delayed and irregular in the mutant, and the majority of the mutant microspores failed to undergo mitotic divisions. Enzyme activities of alcohol dehydrogenase and esterases decreased in the mutant soon after meiosis and were undetectable in mature pollen grains of the mutant. RNA accumulation was also diminished. These results are discussed in relation to the possible role(s) of adenine salvage in pollen development. PMID:12354970

  18. Pooled Analysis of the Prognostic and Predictive Effects of KRAS Mutation Status and KRAS Mutation Subtype in Early-Stage Resected Non–Small-Cell Lung Cancer in Four Trials of Adjuvant Chemotherapy

    PubMed Central

    Shepherd, Frances A.; Domerg, Caroline; Hainaut, Pierre; Jänne, Pasi A.; Pignon, Jean-Pierre; Graziano, Stephen; Douillard, Jean-Yves; Brambilla, Elizabeth; Le Chevalier, Thierry; Seymour, Lesley; Bourredjem, Abderrahmane; Teuff, Gwénaël Le; Pirker, Robert; Filipits, Martin; Rosell, Rafael; Kratzke, Robert; Bandarchi, Bizhan; Ma, Xiaoli; Capelletti, Marzia; Soria, Jean-Charles; Tsao, Ming-Sound

    2013-01-01

    Purpose We undertook this analysis of KRAS mutation in four trials of adjuvant chemotherapy (ACT) versus observation (OBS) to clarify the prognostic/predictive roles of KRAS in non–small-cell lung cancer (NSCLC). Methods KRAS mutation was determined in blinded fashion. Exploratory analyses were performed to characterize relationships between mutation status and subtype and survival outcomes using a multivariable Cox model. Results Among 1,543 patients (763 OBS, 780 ACT), 300 had KRAS mutations (codon 12, n = 275; codon 13, n = 24; codon 14, n = 1). In OBS patients, there was no prognostic difference for overall survival for codon-12 (mutation v wild type [WT] hazard ratio [HR] = 1.04; 95% CI, 0.77 to 1.40) or codon-13 (HR = 1.01; 95% CI, 0.47 to 2.17) mutations. No significant benefit from ACT was observed for WT-KRAS (ACT v OBS HR = 0.89; 95% CI, 0.76 to 1.04; P = .15) or codon-12 mutations (HR = 0.95; 95% CI, 0.67 to 1.35; P = .77); with codon-13 mutations, ACT was deleterious (HR = 5.78; 95% CI, 2.06 to 16.2; P < .001; interaction P = .002). There was no prognostic effect for specific codon-12 amino acid substitution. The effect of ACT was variable among patients with codon-12 mutations: G12A or G12R (HR = 0.66; P = .48), G12C or G12V (HR = 0.94; P = .77) and G12D or G12S (HR = 1.39; P = .48; comparison of four HRs, including WT, interaction P = .76). OBS patients with KRAS-mutated tumors were more likely to develop second primary cancers (HR = 2.76, 95% CI, 1.34 to 5.70; P = .005) but not ACT patients (HR = 0.66; 95% CI, 0.25 to 1.75; P = .40; interaction, P = .02). Conclusion KRAS mutation status is not significantly prognostic. The potential interaction in patients with codon-13 mutations requires validation. At this time, KRAS status cannot be recommended to select patients with NSCLC for ACT. PMID:23630215

  19. Induction of MDM2-P2 Transcripts Correlates with Stabilized Wild-Type p53 in Betel- and Tobacco-Related Human Oral Cancer

    PubMed Central

    Ralhan, Ranju; Sandhya, Agarwal; Meera, Mathur; Bohdan, Wasylyk; Nootan, Shukla K.

    2000-01-01

    MDM2, a critical element of cellular homeostasis mechanisms, is involved in complex interactions with important cell-cycle and stress-response regulators including p53. The mdm2-P2 promoter is a transcriptional target of p53. The aim of this study was to determine the association between mdm2-P2 transcripts and the status of the p53 gene in betel- and tobacco-related oral squamous cell carcinomas (SCCs) to understand the mechanism of deregulation of MDM2 and p53 expression and their prognostic implications in oral tumorigenesis. Elevated levels of MDM2 proteins were observed in 11 of 25 (44%) oral hyperplastic lesions, nine of 15 (60%) dysplastic lesions, and 71 of 100 (71%) SCCs. The intriguing feature of the study was the identification and different subcellular localization of three isoforms of MDM2 (ie, 90 kd, 76 kd, and 57 kd) in oral SCCs and their correlation with p53 overexpression in each tumor. The hallmark of the study was the detection of mdm2-P2 transcripts in 12 of 20 oral SCCs overexpressing both MDM2 and p53 proteins while harboring wild-type p53 alleles. Furthermore, mdm2 amplification was an infrequent event in betel- and tobacco-associated oral tumorigenesis. The differential compartmentalization of the three isoforms of MDM2 suggests that each has a distinct function, potentially in the regulation of p53 and other gene products implicated in oral tumorigenesis. In conclusion, we report herein the first evidence suggesting that enhanced translation of mdm2-P2 transcripts (S-mdm2) may represent an important mechanism of overexpression and consequent stabilization and functional inactivation of wild-type p53 serving as an adverse prognosticator in betel- and tobacco-related oral cancer. The clinical significance of the functional inactivation of wild-type p53 by MDM2 is underscored by the significantly shorter median disease-free survival time (16 months) observed in p53/MDM2-positive cases as compared to those which did not show co-expression of

  20. Induction of MDM2-P2 transcripts correlates with stabilized wild-type p53 in betel- and tobacco-related human oral cancer.

    PubMed

    Ralhan, R; Sandhya, A; Meera, M; Bohdan, W; Nootan, S K

    2000-08-01

    MDM2, a critical element of cellular homeostasis mechanisms, is involved in complex interactions with important cell-cycle and stress-response regulators including p53. The mdm2-P2 promoter is a transcriptional target of p53. The aim of this study was to determine the association between mdm2-P2 transcripts and the status of the p53 gene in betel- and tobacco-related oral squamous cell carcinomas (SCCs) to understand the mechanism of deregulation of MDM2 and p53 expression and their prognostic implications in oral tumorigenesis. Elevated levels of MDM2 proteins were observed in 11 of 25 (44%) oral hyperplastic lesions, nine of 15 (60%) dysplastic lesions, and 71 of 100 (71%) SCCs. The intriguing feature of the study was the identification and different subcellular localization of three isoforms of MDM2 (ie, 90 kd, 76 kd, and 57 kd) in oral SCCs and their correlation with p53 overexpression in each tumor. The hallmark of the study was the detection of mdm2-P2 transcripts in 12 of 20 oral SCCs overexpressing both MDM2 and p53 proteins while harboring wild-type p53 alleles. Furthermore, mdm2 amplification was an infrequent event in betel- and tobacco-associated oral tumorigenesis. The differential compartmentalization of the three isoforms of MDM2 suggests that each has a distinct function, potentially in the regulation of p53 and other gene products implicated in oral tumorigenesis. In conclusion, we report herein the first evidence suggesting that enhanced translation of mdm2-P2 transcripts (S-mdm2) may represent an important mechanism of overexpression and consequent stabilization and functional inactivation of wild-type p53 serving as an adverse prognosticator in betel- and tobacco-related oral cancer. The clinical significance of the functional inactivation of wild-type p53 by MDM2 is underscored by the significantly shorter median disease-free survival time (16 months) observed in p53/MDM2-positive cases as compared to those which did not show co-expression of

  1. An emerging role for misfolded wild-type SOD1 in sporadic ALS pathogenesis

    PubMed Central

    Rotunno, Melissa S.; Bosco, Daryl A.

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that targets motor neurons, leading to paralysis and death within a few years of disease onset. While several genes have been linked to the inheritable, or familial, form of ALS, much less is known about the cause(s) of sporadic ALS, which accounts for ~90% of ALS cases. Due to the clinical similarities between familial and sporadic ALS, it is plausible that both forms of the disease converge on a common pathway and, therefore, involve common factors. Recent evidence suggests the Cu,Zn-superoxide dismutase (SOD1) protein to be one such factor that is common to both sporadic and familial ALS. In 1993, mutations were uncovered in SOD1 that represent the first known genetic cause of familial ALS. While the exact mechanism of mutant-SOD1 toxicity is still not known today, most evidence points to a gain of toxic function that stems, at least in part, from the propensity of this protein to misfold. In the wild-type SOD1 protein, non-genetic perturbations such as metal depletion, disruption of the quaternary structure, and oxidation, can also induce SOD1 to misfold. In fact, these aforementioned post-translational modifications cause wild-type SOD1 to adopt a “toxic conformation” that is similar to familial ALS-linked SOD1 variants. These observations, together with the detection of misfolded wild-type SOD1 within human post-mortem sporadic ALS samples, have been used to support the controversial hypothesis that misfolded forms of wild-type SOD1 contribute to sporadic ALS pathogenesis. In this review, we present data from the literature that both support and contradict this hypothesis. We also discuss SOD1 as a potential therapeutic target for both familial and sporadic ALS. PMID:24379756

  2. Stability of Iowa mutant and wild type Aβ-peptide aggregates

    SciTech Connect

    Alred, Erik J.; Scheele, Emily G.; Berhanu, Workalemahu M.; Hansmann, Ulrich H. E.

    2014-11-07

    Recent experiments indicate a connection between the structure of amyloid aggregates and their cytotoxicity as related to neurodegenerative diseases. Of particular interest is the Iowa Mutant, which causes early-onset of Alzheimer's disease. While wild-type Amyloid β-peptides form only parallel beta-sheet aggregates, the mutant also forms meta-stable antiparallel beta sheets. Since these structural variations may cause the difference in the pathological effects of the two Aβ-peptides, we have studied in silico the relative stability of the wild type and Iowa mutant in both parallel and antiparallel forms. We compare regular molecular dynamics simulations with such where the viscosity of the samples is reduced, which, we show, leads to higher sampling efficiency. By analyzing and comparing these four sets of all-atom molecular dynamics simulations, we probe the role of the various factors that could lead to the structural differences. Our analysis indicates that the parallel forms of both wild type and Iowa mutant aggregates are stable, while the antiparallel aggregates are meta-stable for the Iowa mutant and not stable for the wild type. The differences result from the direct alignment of hydrophobic interactions in the in-register parallel oligomers, making them more stable than the antiparallel aggregates. The slightly higher thermodynamic stability of the Iowa mutant fibril-like oligomers in its parallel organization over that in antiparallel form is supported by previous experimental measurements showing slow inter-conversion of antiparallel aggregates into parallel ones. Knowledge of the mechanism that selects between parallel and antiparallel conformations and determines their relative stability may open new avenues for the development of therapies targeting familial forms of early-onset Alzheimer's disease.

  3. Root graviresponsiveness and cellular differentiation in wild-type and a starchless mutant of Arabidopsis thaliana

    NASA Technical Reports Server (NTRS)

    Moore, R.

    1989-01-01

    Primary roots of a starchless mutant of Arabidopsis thaliana L. are strongly graviresponsive despite lacking amyloplasts in their columella cells. The ultrastructures of calyptrogen and peripheral cells in wild-type as compared to mutant seedlings are not significantly different. The largest difference in cellular differentiation in caps of mutant and wild-type roots is the relative volume of plastids in columella cells. Plastids occupy 12.3% of the volume of columella cells in wild-type seedlings, but only 3.69% of columella cells in mutant seedlings. These results indicate that: (1) amyloplasts and starch are not necessary for root graviresponsiveness; (2) the increase in relative volume of plastids that usually accompanies differentiation of columella cells is not necessary for root graviresponsiveness; and (3) the absence of starch and amyloplasts does not affect the structure of calyptrogen (i.e. meristematic) and secretory (i.e. peripheral) cells in root caps. These results are discussed relative to proposed models for root gravitropism.

  4. A Snapshot of Histone Modifications within Transposable Elements in Drosophila Wild Type Strains

    PubMed Central

    Rebollo, Rita; Horard, Béatrice; Begeot, Flora; Delattre, Marion; Gilson, Eric; Vieira, Cristina

    2012-01-01

    Transposable elements (TEs) are a major source of genetic variability in genomes, creating genetic novelty and driving genome evolution. Analysis of sequenced genomes has revealed considerable diversity in TE families, copy number, and localization between different, closely related species. For instance, although the twin species Drosophila melanogaster and D. simulans share the same TE families, they display different amounts of TEs. Furthermore, previous analyses of wild type derived strains of D. simulans have revealed high polymorphism regarding TE copy number within this species. Several factors may influence the diversity and abundance of TEs in a genome, including molecular mechanisms such as epigenetic factors, which could be a source of variation in TE success. In this paper, we present the first analysis of the epigenetic status of four TE families (roo, tirant, 412 and F) in seven wild type strains of D. melanogaster and D. simulans. Our data shows intra- and inter-specific variations in the histone marks that adorn TE copies. Our results demonstrate that the chromatin state of common TEs varies among TE families, between closely related species and also between wild type strains. PMID:22962605

  5. Interaction of root gravitropism and phototropism in Arabidopsis wild-type and starchless mutants

    NASA Technical Reports Server (NTRS)

    Vitha, S.; Zhao, L.; Sack, F. D.

    2000-01-01

    Root gravitropism in wild-type Arabidopsis and in two starchless mutants, pgm1-1 and adg1-1, was evaluated as a function of light position to determine the relative strengths of negative phototropism and of gravitropism and how much phototropism affects gravitropic measurements. Gravitropism was stronger than phototropism in some but not all light positions in wild-type roots grown for an extended period, indicating that the relationship between the two tropisms is more complex than previously reported. Root phototropism significantly influenced the time course of gravitropic curvature and the two measures of sensitivity. Light from above during horizontal exposure overestimated all three parameters for all three genotypes except the wild-type perception time. At the irradiance used (80 micromol m(-2) s(-1)), the shortest periods of illumination found to exaggerate gravitropism were 45 min of continuous illumination and 2-min doses of intermittent illumination. By growing roots in circumlateral light or by gravistimulating in the dark, corrected values were obtained for each gravitropic parameter. Roots of both starchless mutants were determined to be about three times less sensitive than prior estimates. This study demonstrates the importance of accounting for phototropism in the design of root gravitropism experiments in Arabidopsis.

  6. Physiology and metabolic fluxes of wild-type and riboflavin-producing Bacillus subtilis.

    PubMed Central

    Sauer, U; Hatzimanikatis, V; Hohmann, H P; Manneberg, M; van Loon, A P; Bailey, J E

    1996-01-01

    Continuous cultivation in a glucose-limited chemostat was used to determine the growth parameters of wild-type Bacillus subtilis and of a recombinant, riboflavin-producing strain. Maintenance coefficients of 0.45 and 0.66 mmol of glucose g-1 h-1 were determined for the wild-type and recombinant strains, respectively. However, the maximum molar growth yield of 82 to 85 g (cell dry weight)/mol of glucose was found to be almost identical in both strains. A nonlinear relationship between the specific riboflavin production rate and the dilution rate was observed, revealing a coupling of product formation and growth under strict substrate-limited conditions. Most prominently, riboflavin formation completely ceased at specific growth rates below 0.15 h-1. For molecular characterization of B. subtilis, the total amino acid composition of the wild type was experimentally determined and the complete building block requirements for biomass formation were derived. In particular, the murein sacculus was found to constitute approximately 9% of B. subtilis biomass, three- to fivefold more than in Escherichia coli. Estimation of intracellular metabolic fluxes by a refined mass balance approach revealed a substantial, growth rate-dependent flux through the oxidative branch of the pentose phosphate pathway. Furthermore, this flux is indicated to be increased in the strain engineered for riboflavin formation. Glucose catabolism at low growth rates with reduced biomass yields was supported mainly by the tricarboxylic acid cycle. PMID:8837424

  7. In vitro Intestinal Mucosal Epithelial Responses to Wild-Type Salmonella Typhi and Attenuated Typhoid Vaccines.

    PubMed

    Fiorentino, Maria; Lammers, Karen M; Levine, Myron M; Sztein, Marcelo B; Fasano, Alessio

    2013-01-01

    Typhoid fever, caused by S. Typhi, is responsible for approximately 200,000 deaths per year worldwide. Little information is available regarding epithelium-bacterial interactions in S. Typhi infection. We have evaluated in vitro the effects of wild-type S. Typhi, the licensed Ty21a typhoid vaccine and the leading strains CVD 908-htrA and CVD 909 vaccine candidates on intestinal barrier function and immune response. Caco2 monolayers infected with wild-type S. Typhi exhibited alterations in the organization of tight junctions, increased paracellular permeability, and a rapid decrease in Trans-Epithelial Electrical Resistance as early as 4 h post-exposure. S. Typhi triggered the secretion of interleukin (IL)-8 and IL-6. Caco2 cells infected with the attenuated strains exhibited a milder pro-inflammatory response with minimal disruption of the barrier integrity. We conclude that wild-type S. Typhi causes marked transient alterations of the intestinal mucosa that are more pronounced than those observed with Ty21a or new generation attenuated typhoid vaccine candidates. PMID:23408152

  8. Comparative proteomic analysis of tobacco expressing cyanobacterial flavodoxin and its wild type under drought stress.

    PubMed

    Gharechahi, Javad; Hajirezaei, Mohammad-Reza; Salekdeh, Ghasem Hosseini

    2015-03-01

    Tobacco plants expressing cyanobacterial flavodoxin (Fld) show enhanced tolerance to a wide range of abiotic stresses including drought, temperature and UV. The mechanisms of adaptation to stress conditions under Fld expression are largely unknown. Here, we applied comparative proteomic analysis to uncover the changes in the proteome profile of Fld-expressing plants in response to drought stress. Using high-resolution two-dimensional gel electrophoresis, we were able to detect 930 protein spots and compare their abundance. We found changes up to 1.5 fold for 52 spots under drought in transgenic and/or wild type plants. Using combined MALDI-TOF/TOF and ESI-Q/TOF analysis 39 (24 in wild type, 11 in transgenic, and 4 in both) drought-responsive proteins (DRPs) could be identified. The majority of DRPs are known to be involved in photosynthesis, carbohydrate and energy metabolism, amino acid and protein synthesis and processing, and oxidative stress responses. Among candidate DRPs, the abundance of remurin, ferredoxin-NADP reductase, chloroplast manganese stabilizing protein-II, phosphoglycerate mutase, and glutathione S-transferase decreased in drought stressed Fld-tobacco while S-formylglutathione hydrolase and pyridoxine biosynthesis protein abundance increased. In wild type plants, drought caused a reduction of proteins related to carbohydrate metabolism. These results suggest that the stress tolerance conferred by Fld expression is strongly related to control mechanisms regarding carbohydrate and energy metabolism as well as oxidative stress responses. PMID:25506766

  9. Clavulanic acid production by the MMS 150 mutant obtained from wild type Streptomyces clavuligerus ATCC 27064

    PubMed Central

    da Silva Vasconcelos, Eliton; de Lima, Vanderlei Aparecido; Goto, Leandro Seiji; Cruz-Hernández, Isara Lourdes; Hokka, Carlos Osamu

    2013-01-01

    Clavulanic acid (CA) is a powerful inhibitor of the beta-lactamases, enzymes produced by bacteria resistants to penicillin and cefalosporin. This molecule is produced industrially by strains of Streptomyces clavuligerus in complex media which carbon and nitrogen resources are supplied by inexpensive compounds still providing high productivity. The genetic production improvement using physical and chemical mutagenic agents is an important strategy in programs of industrial production development of bioactive metabolites. However, parental strains are susceptible to loss of their original productivity due genetic instability phenomenona. In this work, some S. clavuligerus mutant strains obtained by treatment with UV light and with MMS are compared with the wild type (Streptomyces clavuligerus ATCC 27064). The results indicated that the random mutations originated some strains with different phenotypes, most divergent demonstrated by the mutants strains named AC116, MMS 150 and MMS 54, that exhibited lack of pigmentation in their mature spores. Also, the strain MMS 150 presented a larger production of CA when cultivated in semi-synthetics media. Using other media, the wild type strain obtained a larger CA production. Besides, using the modifed complex media the MMS 150 strain showed changes in its lipolitic activity and a larger production of CA. The studies also allowed finding the best conditions for a lipase activity exhibited by wild type S. clavuligerus and the MMS150 mutant. PMID:24688492

  10. System-wide identification of wild-type SUMO-2 conjugation sites

    PubMed Central

    Hendriks, Ivo A.; D'Souza, Rochelle C.; Chang, Jer-Gung; Mann, Matthias; Vertegaal, Alfred C. O.

    2015-01-01

    SUMOylation is a reversible post-translational modification (PTM) regulating all nuclear processes. Identification of SUMOylation sites by mass spectrometry (MS) has been hampered by bulky tryptic fragments, which thus far necessitated the use of mutated SUMO. Here we present a SUMO-specific protease-based methodology which circumvents this problem, dubbed Protease-Reliant Identification of SUMO Modification (PRISM). PRISM allows for detection of SUMOylated proteins as well as identification of specific sites of SUMOylation while using wild-type SUMO. The method is generic and could be widely applied to study lysine PTMs. We employ PRISM in combination with high-resolution MS to identify SUMOylation sites from HeLa cells under standard growth conditions and in response to heat shock. We identified 751 wild-type SUMOylation sites on endogenous proteins, including 200 dynamic SUMO sites in response to heat shock. Thus, we have developed a method capable of quantitatively studying wild-type mammalian SUMO at the site-specific and system-wide level. PMID:26073453

  11. Performance and Cost Efficiency of KRAS Mutation Testing for Metastatic Colorectal Cancer in Routine Diagnosis: The MOKAECM Study, a Nationwide Experience

    PubMed Central

    Chatellier, Gilles; Côté, Jean-François; Pages, Jean-Christophe; de Fraipont, Florence; Boyer, Jean-Christophe; Merlio, Jean Philippe; Morel, Alain; Gorisse, Marie-Claude; de Cremoux, Patricia; Leroy, Karen; Milano, Gérard; Ouafik, L’Houcine; Merlin, Jean-Louis; Le Corre, Delphine; Aucouturier, Pascaline; Sabourin, Jean-Christophe; Nowak, Frédérique; Frebourg, Thierry; Emile, Jean-François; Durand-Zaleski, Isabelle; Laurent-Puig, Pierre

    2013-01-01

    Purpose Rapid advances in the understanding of cancer biology have transformed drug development thus leading to the approval of targeted therapies and to the development of molecular tests to select patients that will respond to treatments. KRAS status has emerged as a negative predictor of clinical benefit from anti-EGFR antibodies in colorectal cancer, and anti-EGFR antibodies use was limited to KRAS wild type tumors. In order to ensure wide access to tumor molecular profiling, the French National Cancer Institute (INCa) has set up a national network of 28 regional molecular genetics centers. Concurrently, a nationwide external quality assessment for KRAS testing (MOKAECM) was granted to analyze reproducibility and costs. Methods 96 cell-line DNAs and 24 DNA samples from paraffin embedded tumor tissues were sent to 40 French laboratories. A total of 5448 KRAS results were collected and analyzed and a micro-costing study was performed on sites for 5 common methods by an independent team of health economists. Results This work provided a baseline picture of the accuracy and reliability of KRAS analysis in routine testing conditions at a nationwide level. Inter-laboratory Kappa values were >0.8 for KRAS results despite differences detection methods and the use of in-house technologies. Specificity was excellent with only one false positive in 1128 FFPE data, and sensitivity was higher for targeted techniques as compared to Sanger sequencing based methods that were dependent upon local expertise. Estimated reagent costs per patient ranged from €5.5 to €19.0. Conclusion The INCa has set-up a network of public laboratories dedicated to molecular oncology tests. Our results showed almost perfect agreements in KRAS testing at a nationwide level despite different testing methods ensuring a cost-effective equal access to personalized colorectal cancer treatment. PMID:23935912

  12. The orl rat is more responsive to methacholine challenge than wild type

    PubMed Central

    Rodriguez, Elena; Barthold, Julia S.; Kreiger, Portia A.; Armani, Milena Hirata; Wang, Jordan; Michelini, Katherine A.; Wolfson, Marla R.; Boyce, Roberta; Barone, Carol A.; Zhu, Yan; Waldman, Scott A.; Shaffer, Thomas H.

    2015-01-01

    Background This study presents an animal model of native airway hyperresponsiveness (AHR). AHR is a fundamental aspect of asthma and reflects an abnormal response characterized by airway narrowing following exposure to a wide variety of non-immunological stimuli. Undescended testis (UDT) is one of the most common male congenital anomalies. The orl rat is a Long Evans substrain with inherited UDT. Since boys born with congenital UDT are more likely to manifest asthma symptoms, the main aim in of this study was to investigate the alternative hypothesis that orl rats have greater AHR to a methacholine aerosol challenge than wild type rats. Methods Long Evans wild type (n = 9) and orl (n = 13) rats were anesthetized, tracheostomized, and mechanically ventilated at 4 weeks of age. Escalating concentrations of inhaled methacholine were delivered. The methacholine potency and efficacy in the strains were measured. Respiratory resistance was the primary endpoint. After the final methacholine aerosol challenge, the short-acting β2-adrenoceptor agonist albuterol was administered as an aerosol and lung/diaphragm tissues were assayed for interleukin (IL)-4, IL-6, and tumor necrosis factor (TNF)-α. Histological and histomorphometrical analyses were performed. Results The methacholine concentratione-response curve in the orl group indicated increased sensitivity, hyperreactivity, and exaggerated maximal response in comparison with the wild type group, indicating that orl rats had abnormally greater AHR responses to methacholine. Histological findings in orl rats showed the presence of eosinophils, unlike wild type rats. β2-Adrenoceptor agonist intervention resulted in up-regulation of IL-4 diaphragmatic levels and down-regulation of IL-4 and IL-6 in the lungs of orl rats. Conclusion orl rats had greater AHR than wild type rats during methacholine challenge, with higher IL-4 levels in diaphragmatic tissue homogenates. Positive immunostaining for IL-4 was detected in lung and

  13. Comparative effects of chlorpyrifos in wild type and cannabinoid Cb1 receptor knockout mice

    SciTech Connect

    Baireddy, Praveena; Liu, Jing; Hinsdale, Myron; Pope, Carey

    2011-11-15

    Endocannabinoids (eCBs) modulate neurotransmission by inhibiting the release of a variety of neurotransmitters. The cannabinoid receptor agonist WIN 55.212-2 (WIN) can modulate organophosphorus (OP) anticholinesterase toxicity in rats, presumably by inhibiting acetylcholine (ACh) release. Some OP anticholinesterases also inhibit eCB-degrading enzymes. We studied the effects of the OP insecticide chlorpyrifos (CPF) on cholinergic signs of toxicity, cholinesterase activity and ACh release in tissues from wild type (+/+) and cannabinoid CB1 receptor knockout (-/-) mice. Mice of both genotypes (n = 5-6/treatment group) were challenged with CPF (300 mg/kg, 2 ml/kg in peanut oil, sc) and evaluated for functional and neurochemical changes. Both genotypes exhibited similar cholinergic signs and cholinesterase inhibition (82-95% at 48 h after dosing) in cortex, cerebellum and heart. WIN reduced depolarization-induced ACh release in vitro in hippocampal slices from wild type mice, but had no effect in hippocampal slices from knockouts or in striatal slices from either genotype. Chlorpyrifos oxon (CPO, 100 {mu}M) reduced release in hippocampal slices from both genotypes in vitro, but with a greater reduction in tissues from wild types (21% vs 12%). CPO had no significant in vitro effect on ACh release in striatum. CPF reduced ACh release in hippocampus from both genotypes ex vivo, but reduction was again significantly greater in tissues from wild types (52% vs 36%). In striatum, CPF led to a similar reduction (20-23%) in tissues from both genotypes. Thus, while CB1 deletion in mice had little influence on the expression of acute toxicity following CPF, CPF- or CPO-induced changes in ACh release appeared sensitive to modulation by CB1-mediated eCB signaling in a brain-regional manner. -- Highlights: Black-Right-Pointing-Pointer C57Bl/6 mice showed dose-related cholinergic toxicity following subcutaneous chlorpyrifos exposure. Black-Right-Pointing-Pointer Wild type and

  14. Biomass Productivities in Wild Type and Pigment Mutant of Cyclotella sp. (Diatom)

    SciTech Connect

    Huesemann, Michael H.; Hausmann, Tom S.; Bartha, Richard; Aksoy, M.; Weissman, Joseph C.; Benemann, John

    2008-07-03

    Microalgae are expected to play a significant role in greenhouse gas mitigation because they can utilize CO2 from powerplant flue gases directly while producing a variety of renewable carbon-neutral biofuels. In order for such a microalgal climate change mitigation strategy to become economically feasible, it will be necessary to significantly improve biomass productivities. One approach to achieve this objective is to reduce, via mutagenesis, the number of light harvesting pigments, which, according to theory, should significantly improve the light utilization efficiency, primarily by increasing the light intensity at which photosynthesis saturates (Is). Employing chemical (ethylmethylsulfonate, EMS) and UV mutagenesis of a wild type strain of the diatom Cyclotella, approximately 10,000 pigment mutants were generated, and two of the most promising ones (CM1 and CM1-1) were subjected to further testing in both laboratory cultures and outdoor ponds. Measurements of photosynthetic oxygen production rates as a function of light intensity (i.e., P-I curves) of samples taken from laboratory batch cultures during the exponential and linear growth phase indicated that the light intensity at which photosynthesis saturates (Is) was two to three times greater in the pigment mutant CM1-1 than in the wild type, i.e., 355-443 versus 116-169 μmole/m2∙sec, respectively. While theory, i.e., the Bush equation, predicts that such a significant gain in Is should increase light utilization efficiencies and thus biomass productivities, particularly at high light intensities, no improvements in biomass productivities were observed in either semi-continuous laboratory cultures or outdoor ponds. In fact, the maximum biomass productivity in semi-continuous laboratory culture was always greater in the wild type than in the mutant, namely 883 versus 725 mg/L∙d, respectively at low light intensity (200 μmole/m2∙sec) and 1229 versus 1043 mg/L∙d, respectively at high light intensity

  15. Targeting KRAS Oncogene in Colon Cancer Cells with 7-Carboxylate Indolo[3,2-b]quinoline Tri-Alkylamine Derivatives

    PubMed Central

    Brito, Hugo; Martins, Ana Cláudia; Lavrado, João; Mendes, Eduarda; Francisco, Ana Paula; Santos, Sofia A.; Ohnmacht, Stephan A.; Kim, Nam-Soon; Rodrigues, Cecília M. P.; Moreira, Rui; Neidle, Stephen; Borralho, Pedro M.; Paulo, Alexandra

    2015-01-01

    Background A guanine-rich strand within the promoter of the KRAS gene can fold into an intra-molecular G-quadruplex structure (G4), which has an important role in the regulation of KRAS transcription. We have previously identified indolo[3,2-b]quinolines with a 7-carboxylate group and three alkylamine side chains (IQ3A) as effective G4 stabilizers and promising selective anticancer leads. Herein we investigated the anticancer mechanism of action of these compounds, which we hypothesized due to stabilization of the G4 sequence in the KRAS promoter and subsequent down-regulation of gene expression. Methodology/Principal Findings IQ3A compounds showed greater stabilization of G4 compared to duplex DNA structures and reduced KRAS promoter activity in a dual luciferase reporter assay. Moreover, IQ3A compounds showed high anti-proliferative activity in HCT116 and SW620 colon cancer cells (IC50 < 2.69 μM), without eliciting cell death in non-malignant HEK293T human embryonic kidney, and human colon fibroblasts CCD18co. IQ3A compounds significantly reduced KRAS mRNA and protein steady-state levels at IC50 concentrations, and increased p53 protein steady-state levels and cell death by apoptosis in HCT116 cells (mut KRAS, wt p53). Furthermore, KRAS silencing in HCT116 p53 wild-type (p53(+/+)) and null (p53(-/-)) isogenic cell lines induced a higher level of cell death, and a higher IQ3A-induced cell death in HCT116 p53(+/+) compared to HCT116 p53(-/-). Conclusions Herein we provide evidence that G4 ligands such as IQ3A compounds can target G4 motifs present in KRAS promoter, down-regulate the expression of the mutant KRAS gene through inhibition of transcription and translation, and induce cell death by apoptosis in colon cancer cell lines. Thus, targeting KRAS at the genomic level with G4 ligands may be a new anticancer therapy strategy for colon cancer. PMID:26024321

  16. Bone turnover in wild type and pleiotrophin-transgenic mice housed for three months in the International Space Station (ISS).

    PubMed

    Tavella, Sara; Ruggiu, Alessandra; Giuliani, Alessandra; Brun, Francesco; Canciani, Barbara; Manescu, Adrian; Marozzi, Katia; Cilli, Michele; Costa, Delfina; Liu, Yi; Piccardi, Federica; Tasso, Roberta; Tromba, Giuliana; Rustichelli, Franco; Cancedda, Ranieri

    2012-01-01

    Bone is a complex dynamic tissue undergoing a continuous remodeling process. Gravity is a physical force playing a role in the remodeling and contributing to the maintenance of bone integrity. This article reports an investigation on the alterations of the bone microarchitecture that occurred in wild type (Wt) and pleiotrophin-transgenic (PTN-Tg) mice exposed to a near-zero gravity on the International Space Station (ISS) during the Mice Drawer System (MDS) mission, to date, the longest mice permanence (91 days) in space. The transgenic mouse strain over-expressing pleiotrophin (PTN) in bone was selected because of the PTN positive effects on bone turnover. Wt and PTN-Tg control animals were maintained on Earth either in a MDS payload or in a standard vivarium cage. This study revealed a bone loss during spaceflight in the weight-bearing bones of both strains. For both Tg and Wt a decrease of the trabecular number as well as an increase of the mean trabecular separation was observed after flight, whereas trabecular thickness did not show any significant change. Non weight-bearing bones were not affected. The PTN-Tg mice exposed to normal gravity presented a poorer trabecular organization than Wt mice, but interestingly, the expression of the PTN transgene during the flight resulted in some protection against microgravity's negative effects. Moreover, osteocytes of the Wt mice, but not of Tg mice, acquired a round shape, thus showing for the first time osteocyte space-related morphological alterations in vivo. The analysis of specific bone formation and resorption marker expression suggested that the microgravity-induced bone loss was due to both an increased bone resorption and a decreased bone deposition. Apparently, the PTN transgene protection was the result of a higher osteoblast activity in the flight mice. PMID:22438896

  17. De novo establishment of wild-type song culture in the zebra finch.

    PubMed

    Fehér, Olga; Wang, Haibin; Saar, Sigal; Mitra, Partha P; Tchernichovski, Ofer

    2009-05-28

    Culture is typically viewed as consisting of traits inherited epigenetically, through social learning. However, cultural diversity has species-typical constraints, presumably of genetic origin. A celebrated, if contentious, example is whether a universal grammar constrains syntactic diversity in human languages. Oscine songbirds exhibit song learning and provide biologically tractable models of culture: members of a species show individual variation in song and geographically separated groups have local song dialects. Different species exhibit distinct song cultures, suggestive of genetic constraints. Without such constraints, innovations and copying errors should cause unbounded variation over multiple generations or geographical distance, contrary to observations. Here we report an experiment designed to determine whether wild-type song culture might emerge over multiple generations in an isolated colony founded by isolates, and, if so, how this might happen and what type of social environment is required. Zebra finch isolates, unexposed to singing males during development, produce song with characteristics that differ from the wild-type song found in laboratory or natural colonies. In tutoring lineages starting from isolate founders, we quantified alterations in song across tutoring generations in two social environments: tutor-pupil pairs in sound-isolated chambers and an isolated semi-natural colony. In both settings, juveniles imitated the isolate tutors but changed certain characteristics of the songs. These alterations accumulated over learning generations. Consequently, songs evolved towards the wild-type in three to four generations. Thus, species-typical song culture can appear de novo. Our study has parallels with language change and evolution. In analogy to models in quantitative genetics, we model song culture as a multigenerational phenotype partly encoded genetically in an isolate founding population, influenced by environmental variables and taking

  18. Efavirenz concentrations in CSF exceed IC50 for wild-type HIV

    PubMed Central

    Best, Brookie M.; Koopmans, Peter P.; Letendre, Scott L.; Capparelli, Edmund V.; Rossi, Steven S.; Clifford, David B.; Collier, Ann C.; Gelman, Benjamin B.; Mbeo, Gilbert; McCutchan, J. Allen; Simpson, David M.; Haubrich, Richard; Ellis, Ronald; Grant, Igor; Grant, Igor; McCutchan, J. Allen; Ellis, Ronald J.; Marcotte, Thomas D.; Franklin, Donald; Ellis, Ronald J.; McCutchan, J. Allen; Alexander, Terry; Letendre, Scott; Capparelli, Edmund; Heaton, Robert K.; Atkinson, J. Hampton; Woods, Steven Paul; Dawson, Matthew; Wong, Joseph K.; Fennema-Notestine, Christine; Taylor, Michael J.; Theilmann, Rebecca; Gamst, Anthony C.; Cushman, Clint; Abramson, Ian; Vaida, Florin; Marcotte, Thomas D.; von Jaeger, Rodney; McArthur, Justin; Smith, Mary; Morgello, Susan; Simpson, David; Mintz, Letty; McCutchan, J. Allen; Toperoff, Will; Collier, Ann; Marra, Christina; Jones, Trudy; Gelman, Benjamin; Head, Eleanor; Clifford, David; Al-Lozi, Muhammad; Teshome, Mengesha

    2011-01-01

    Objectives HIV-associated neurocognitive disorders remain common despite use of potent antiretroviral therapy (ART). Ongoing viral replication due to poor distribution of antivirals into the CNS may increase risk for HIV-associated neurocognitive disorders. This study's objective was to determine penetration of a commonly prescribed antiretroviral drug, efavirenz, into CSF. Methods CHARTER is an ongoing, North American, multicentre, observational study to determine the effects of ART on HIV-associated neurological disease. Single random plasma and CSF samples were drawn within 1 h of each other from subjects taking efavirenz between September 2003 and July 2007. Samples were assayed by HPLC or HPLC/mass spectrometry with detection limits of 39 ng/mL (plasma) and <0.1 ng/mL (CSF). Results Eighty participants (age 44 ± 8 years; 79 ± 15 kg; 20 females) had samples drawn 12.5 ± 5.4 h post-dose. The median efavirenz concentrations after a median of 7 months [interquartile range (IQR) 2–17] of therapy were 2145 ng/mL in plasma (IQR 1384–4423) and 13.9 ng/mL in CSF (IQR 4.1–21.2). The CSF/plasma concentration ratio from paired samples drawn within 1 h of each other was 0.005 (IQR 0.0026–0.0076; n = 69). The CSF/IC50 ratio was 26 (IQR 8–41) using the published IC50 for wild-type HIV (0.51 ng/mL). Two CSF samples had concentrations below the efavirenz IC50 for wild-type HIV. Conclusions Efavirenz concentrations in the CSF are only 0.5% of plasma concentrations but exceed the wild-type IC50 in nearly all individuals. Since CSF drug concentrations reflect those in brain interstitial fluids, efavirenz reaches therapeutic concentrations in brain tissue. PMID:21098541

  19. Structural and Morphometric Comparison of Lower Incisors in PACAP-Deficient and Wild-Type Mice.

    PubMed

    Sandor, B; Fintor, K; Reglodi, D; Fulop, D B; Helyes, Z; Szanto, I; Nagy, P; Hashimoto, H; Tamas, A

    2016-06-01

    Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with widespread distribution. PACAP plays an important role in the development of the nervous system, it has a trophic and protective effect, and it is also implicated in the regulation of various physiological functions. Teeth are originated from the mesenchyme of the neural crest and the ectoderm of the first branchial arch, suggesting similarities with the development of the nervous system. Earlier PACAP-immunoreactive fibers have been found in the odontoblastic and subodontoblastic layers of the dental pulp. Our previous examinations have shown that PACAP deficiency causes alterations in the morphology and structure of the developing molars of 7-day-old mice. In our present study, morphometric and structural comparison was performed on the incisors of 1-year-old wild-type and PACAP-deficient mice. Hard tissue density measurements and morphometric comparison were carried out on the mandibles and the lower incisors with micro-CT. For structural examination, Raman microscopy was applied on frontal thin sections of the mandible. With micro-CT morphometrical measurements, the size of the incisors and the relative volume of the pulp to dentin were significantly smaller in the PACAP-deficient group compared to the wild-type animals. The density of calcium hydroxyapatite in the dentin was reduced in the PACAP-deficient mice. No structural differences could be observed in the enamel with Raman microscopy. Significant differences were found in the dentin of PACAP-deficient mice with Raman microscopy, where increased carbonate/phosphate ratio indicates higher intracrystalline disordering. The evaluation of amide III bands in the dentin revealed higher structural diversity in wild-type mice. Based upon our present and previous results, it is obvious that PACAP plays an important role in tooth development with the regulation of morphogenesis, dentin, and enamel mineralization. Further studies are

  20. Genetic variation of the transthyretin gene in wild-type transthyretin amyloidosis (ATTRwt).

    PubMed

    Sikora, Jacquelyn L; Logue, Mark W; Chan, Gloria G; Spencer, Brian H; Prokaeva, Tatiana B; Baldwin, Clinton T; Seldin, David C; Connors, Lawreen H

    2015-01-01

    Wild-type transthyretin amyloidosis (ATTRwt), typically diagnosed as congestive heart failure in elderly Caucasian men, features myocardial amyloid deposits of wild-type plasma protein transthyretin (TTR). ATTRwt is sporadic, its pathogenesis is poorly understood, and currently there are no biomarkers for diagnosis or prognosis. Genetic studies of variant-associated transthyretin amyloidosis have suggested that non-coding TTR gene variants modulate disease. We hypothesized that cis-acting regulatory elements in the TTR gene non-coding regions may modify expression, affecting ATTRwt onset and progression. We studied an ATTRwt cohort consisting of 108 Caucasian males ranging in age from 59 to 87 years with cardiomyopathy due to wild-type TTR deposition; results were compared to 118 anonymous controls matched by age, sex, and race. Four predicted non-coding regulatory regions and all exons in the TTR gene were sequenced using the Sanger method. Eleven common variants were identified; three variants were significantly associated with ATTRwt (p < 0.05), though only one, rs72922940, remained near significance (p corrected = 0.083) after multiple testing correction. Exon analyses demonstrated the occurrence of the p.G26S (G6S) polymorphism in 7 % of ATTRwt subjects and 12 % of controls; this variant was predicted to be a protective factor (p = 0.051). Four variants were significantly associated with age at onset and survival. In this first genetic study of a large, well-characterized cohort of ATTRwt, non-coding and coding variants associated with disease, age at onset, and survival were identified. Further investigation is warranted to determine the prevalence of these variants in ATTRwt, their regulatory function, and potential role in assessing disease risk. PMID:25367359

  1. Capsaicin potentiates wild-type and mutant cystic fibrosis transmembrane conductance regulator chloride-channel currents.

    PubMed

    Ai, Tomohiko; Bompadre, Silvia G; Wang, Xiaohui; Hu, Shenghui; Li, Min; Hwang, Tzyh-Chang

    2004-06-01

    To examine the effects of capsaicin on cystic fibrosis transmembrane conductance regulator (CFTR), we recorded wild-type and mutant CFTR chloride-channel currents using patch-clamp methods. The effects of capsaicin were compared with those of genistein, a well-characterized CFTR activator. In whole-cell experiments, capsaicin potentiates cAMP-stimulated wild-type CFTR currents expressed in NIH 3T3 cells or Chinese hamster ovary cells in a dose-dependent manner with a maximal response approximately 60% of that with genistein and an apparent Kd of 48.4 +/- 6.8 microM. In cell-attached recordings, capsaicin alone fails to activate CFTR in cells that show negligible basal CFTR activity, indicating that capsaicin does not stimulate the cAMP cascade. The magnitude of potentiation with capsaicin depends on the channel activity before drug application; the lower the prestimulated Po, the higher the potentiation. Single-channel kinetic analysis shows that capsaicin potentiates CFTR by increasing the opening rate and decreasing the closing rate of the channel. Capsaicin may act as a partial agonist of genistein because the maximally enhanced wild-type CFTR currents with genistein are partially inhibited by capsaicin. Capsaicin increases DeltaR-CFTR, a protein kinase A (PKA)-independent, constitutively active channel, in cell-attached patches. In excised inside-out patches, capsaicin potentiates the PKA-phosphorylated, ATP-dependent CFTR activity. Both capsaicin and genistein potentiate the cAMP-stimulated G551D-CFTR, DeltaF508-CFTR, and 8SA mutant channel currents. The binding site for capsaicin is probably located at the cytoplasmic domain of CFTR, because pipette application of capsaicin fails to potentiate CFTR activity. In conclusion, capsaicin is a partial agonist of genistein in activation of the CFTR chloride channel. Both compounds affect ATP-dependent gating of CFTR. PMID:15155835

  2. Growth, seed development and genetic analysis in wild type and Def mutant of Pisum sativum L

    PubMed Central

    2011-01-01

    Background The def mutant pea (Pisum sativum L) showed non-abscission of seeds from the funicule. Here we present data on seed development and growth pattern and their relationship in predicting this particular trait in wild type and mutant lines as well as the inheritance pattern of the def allele in F2 and F3 populations. Findings Pod length and seed fresh weight increase with fruit maturity and this may affect the abscission event in pea seeds. However, the seed position in either the distal and proximal ends of the pod did not show any difference. The growth factors of seed fresh weight (FW), width of funicles (WFN), seed width (SW) and seed height (SH) were highly correlated and their relationships were determined in both wild type and def mutant peas. The coefficient of determination R2 values for the relationship between WFN and FW, SW and SH and their various interactions were higher for the def dwarf type. Stepwise multiple regression analysis showed that variation of WFN was associated with SH and SW. Pearson's chi square analysis revealed that the inheritance and segregation of the Def locus in 3:1 ratio was significant in two F2 populations. Structural analysis of the F3 population was used to confirm the inheritance status of the Def locus in F2 heterozygote plants. Conclusions This study investigated the inheritance of the presence or absence of the Def allele, controlling the presence of an abscission zone (AZ) or an abscission-less zone (ALZ) forming in wild type and mutant lines respectively. The single major gene (Def) controlling this phenotype was monogenic and def mutants were characterized and controlled by the homozygous recessive def allele that showed no palisade layers in the hilum region of the seed coat. PMID:22078070

  3. Selective Targeting of the KRAS G12C Mutant: Kicking KRAS When It's Down.

    PubMed

    Hobbs, G Aaron; Wittinghofer, Alfred; Der, Channing J

    2016-03-14

    Two recent studies evaluated a small molecule that specifically binds to and inactivates the KRAS G12C mutant. The new findings argue that the perception that mutant KRAS is persistently frozen in its active GTP-bound form may not be accurate. PMID:26977877

  4. Adaptive thermogenesis and thermal conductance in wild-type and UCP1-KO mice

    PubMed Central

    Willershäuser, Monja; Jastroch, Martin; Rourke, Bryan C.; Fromme, Tobias; Oelkrug, Rebecca; Heldmaier, Gerhard; Klingenspor, Martin

    2010-01-01

    We compared maximal cold-induced heat production (HPmax) and cold limits between warm (WA; 27°C), moderate cold (MCA; 18°C), or cold acclimated (CA; 5°C) wild-type and uncoupling-protein 1 knockout (UCP1-KO) mice. In wild-type mice, HPmax was successively increased after MCA and CA, and the cold limit was lowered to −8.3°C and −18.0°C, respectively. UCP1-KO mice also increased HPmax in response to MCA and CA, although to a lesser extent. Direct comparison revealed a maximal cold-induced recruitment of heat production by +473 mW and +227 mW in wild-type and UCP1-KO mice, respectively. The increase in cold tolerance of UCP1-KO mice from −0.9°C in MCA to −10.1°C in CA could not be directly related to changes in HPmax, indicating that UCP1-KO mice used the dissipated heat more efficiently than wild-type mice. As judged from respiratory quotients, acutely cold-challenged UCP1-KO mice showed a delayed transition toward lipid oxidation, and 5-h cold exposure revealed diminished physical activity and less variability in the control of metabolic rate. We conclude that BAT is required for maximal adaptive thermogenesis but also allows metabolic flexibility and a rapid switch toward sustained lipid-fuelled thermogenesis as an acute response to cold. In both CA groups, expression of contractile proteins (myosin heavy-chain isoforms) showed minor training effects in skeletal muscles, while cardiac muscle of UCP1-KO mice had novel expression of beta cardiac isoform. Neither respiration nor basal proton conductance of skeletal muscle mitochondria were different between genotypes. In subcutaneous white adipose tissue of UCP1-KO mice, cold exposure increased cytochrome-c oxidase activity and expression of the cell death-inducing DFFA-like effector A by 3.6-fold and 15-fold, respectively, indicating the recruitment of mitochondria-rich brown adipocyte-like cells. Absence of functional BAT leads to remodeling of white adipose tissue, which may significantly contribute

  5. Organophosphonate utilization by the wild-type strain of Pseudomonas fluorescens.

    PubMed

    Zboińska, E; Lejczak, B; Kafarski, P

    1992-09-01

    The wild-type strain of Pseudomonas fluorescens was found to utilize a range of structurally diverse organophosphonates as its sole carbon or nitrogen sources. Representative compounds included aminoalkylphosphonates, hydroxyalkylphosphonates, oxoalkylphosphonates, and phosphono dipeptides. Among them, amino(phenyl)methylphosphonate,2-aminoethylphosphonate, aminomethylphosphonate, diisopropyl 9-aminofluoren-9-ylphosphonate, and 2-oxoalkylphosphonates were used by P. fluorescens as its sole sources of phosphorus. Only slight growth was observed on the herbicide glyphosate (N-phosphonomethylglycine), which was metabolized to aminomethylphosphonate. Neither phosphinothricin nor its dialanyl tripeptide, bialaphos, supported growth of P. fluorescens. The possible mechanisms of organophosphonate degradation by this strain are discussed. PMID:1444412

  6. Organophosphonate utilization by the wild-type strain of Pseudomonas fluorescens.

    PubMed Central

    Zboińska, E; Lejczak, B; Kafarski, P

    1992-01-01

    The wild-type strain of Pseudomonas fluorescens was found to utilize a range of structurally diverse organophosphonates as its sole carbon or nitrogen sources. Representative compounds included aminoalkylphosphonates, hydroxyalkylphosphonates, oxoalkylphosphonates, and phosphono dipeptides. Among them, amino(phenyl)methylphosphonate,2-aminoethylphosphonate, aminomethylphosphonate, diisopropyl 9-aminofluoren-9-ylphosphonate, and 2-oxoalkylphosphonates were used by P. fluorescens as its sole sources of phosphorus. Only slight growth was observed on the herbicide glyphosate (N-phosphonomethylglycine), which was metabolized to aminomethylphosphonate. Neither phosphinothricin nor its dialanyl tripeptide, bialaphos, supported growth of P. fluorescens. The possible mechanisms of organophosphonate degradation by this strain are discussed. PMID:1444412

  7. Oxygenated cembranoids from the cultured and wild-type soft corals Sinularia flexibilis.

    PubMed

    Su, Jui-Hsin; Lin, Yu-Fang; Lu, Yi; Yeh, Hsiao-Chien; Wang, Wei-Hsien; Fan, Tung-Yung; Sheu, Jyh-Horng

    2009-11-01

    Two new cembranoids, flexibilisolide A (1) and flexibilisin A (2), along with one known combranoid 5 have been isolated from the cultured soft coral Sinularia flexibilis. Furthermore, two new cembranoids, flexibilisolide B (3) and flexibilisin B (4), along with two known combranoids (5, 6), have been isolated from the wild-type soft coral S. flexibilis. The structures of the new metabolites were determined on the basis of extensive spectroscopic analysis and by comparison of NMR data with those of known compounds. The metabolites 5 and 6 have been shown to exhibit weak cytotoxic activity against MCF-7 cancer cell line. PMID:19881265

  8. Intra-axonal calcium changes after axotomy in wild-type and slow Wallerian degeneration axons.

    PubMed

    Adalbert, R; Morreale, G; Paizs, M; Conforti, L; Walker, S A; Roderick, H L; Bootman, M D; Siklós, L; Coleman, M P

    2012-12-01

    Calcium accumulation induces the breakdown of cytoskeleton and axonal fragmentation in the late stages of Wallerian degeneration. In the early stages there is no evidence for any long-lasting, extensive increase in intra-axonal calcium but there does appear to be some redistribution. We hypothesized that changes in calcium distribution could have an early regulatory role in axonal degeneration in addition to the late executionary role of calcium. Schmidt-Lanterman clefts (SLCs), which allow exchange of metabolites and ions between the periaxonal and extracellular space, are likely to have an increased role when axon segments are separated from the cell body, so we used the oxalate-pyroantimonate method to study calcium at SLCs in distal stumps of transected wild-type and slow Wallerian degeneration (Wld(S)) mutant sciatic nerves, in which Wallerian degeneration is greatly delayed. In wild-type nerves most SLCs show a step gradient of calcium distribution, which is lost at around 20% of SLCs within 3mm of the lesion site by 4-24h after nerve transection. To investigate further the association with Wallerian degeneration, we studied nerves from Wld(S) rats. The step gradient of calcium distribution in Wld(S) is absent in around 20% of the intact nerves beneath SLCs but 4-24h following injury, calcium distribution in transected axons remained similar to that in uninjured nerves. We then used calcium indicators to study influx and buffering of calcium in injured neurites in primary culture. Calcium penetration and the early calcium increase in this system were indistinguishable between Wld(S) and wild-type axons. However, a significant difference was observed during the following hours, when calcium increased in wild-type neurites but not in Wld(S) neurites. We conclude that there is little relationship between calcium distribution and the early stages of Wallerian degeneration at the time points studied in vivo or in vitro but that Wld(S) neurites fail to show a later

  9. Detection of KRAS mutations using double-stranded toehold-exchange probes.

    PubMed

    Wu, Zhenhua; Ma, Tianle; Coll, Jean-Luc; Liu, Fangming; Zhang, Honglian; Ma, Yunfei; Wang, Zhishuo; Jin, Qinghui; Mao, Hongju; Zhao, Jianlong

    2016-06-15

    Detection of KRAS mutations in cancer tissues is immensely valuable for the identification of personalized genotype-based therapy. Here, we employed a double-stranded toehold-exchange probe, which is labeled with fluorescent molecules (FAM) and quenchers (Dabcyl), to detect KRAS mutations in cancer tissues. This probe was able to differentiate the intended mutation in a sample containing as little as 5% mutant alleles in a background of wild-type DNA. This probe also performed robustly at a wide range of conditions, for examples, from 4 °C to 37 °C, from 200 mM Na(+) to 1M Na(+), and from 200 mM K(+) to 500 mM K(+). Furthermore, we validated the practicality of this probe in a clinical setting using 8 pairs of cancer tissue samples and their NT (corresponding adjacent nontumorous tissue) samples. All the results generated from the probe detection agreed with those from direct sequencing. Combining features of extreme high specificity and robustness, this probe is a valuable tool for reliable diagnosis of cancer-related mutations. PMID:26829579

  10. Mutation of NRAS but not KRAS significantly reduces myeloma sensitivity to single-agent bortezomib therapy

    PubMed Central

    Lichter, David I.; Di Bacco, Alessandra; Blakemore, Stephen J.; Berger, Allison; Koenig, Erik; Bernard, Hugues; Trepicchio, William; Li, Bin; Neuwirth, Rachel; Chattopadhyay, Nibedita; Bolen, Joseph B.; Dorner, Andrew J.; van de Velde, Helgi; Ricci, Deborah; Jagannath, Sundar; Berenson, James R.; Richardson, Paul G.; Stadtmauer, Edward A.; Orlowski, Robert Z.; Lonial, Sagar; Anderson, Kenneth C.; Sonneveld, Pieter; San Miguel, Jesús F.; Esseltine, Dixie-Lee; Schu, Matthew

    2014-01-01

    Various translocations and mutations have been identified in myeloma, and certain aberrations, such as t(4;14) and del17, are linked with disease prognosis. To investigate mutational prevalence in myeloma and associations between mutations and patient outcomes, we tested a panel of 41 known oncogenes and tumor suppressor genes in tumor samples from 133 relapsed myeloma patients participating in phase 2 or 3 clinical trials of bortezomib. DNA mutations were identified in 14 genes. BRAF as well as RAS genes were mutated in a large proportion of cases (45.9%) and these mutations were mutually exclusive. New recurrent mutations were also identified, including in the PDGFRA and JAK3 genes. NRAS mutations were associated with a significantly lower response rate to single-agent bortezomib (7% vs 53% in patients with mutant vs wild-type NRAS, P = .00116, Bonferroni-corrected P = .016), as well as shorter time to progression in bortezomib-treated patients (P = .0058, Bonferroni-corrected P = .012). However, NRAS mutation did not impact outcome in patients treated with high-dose dexamethasone. KRAS mutation did not reduce sensitivity to bortezomib or dexamethasone. These findings identify a significant clinical impact of NRAS mutation in myeloma and demonstrate a clear example of functional differences between the KRAS and NRAS oncogenes. PMID:24335104

  11. ALS mutant FUS disrupts nuclear localization and sequesters wild-type FUS within cytoplasmic stress granules

    PubMed Central

    Vance, Caroline; Scotter, Emma L.; Nishimura, Agnes L.; Troakes, Claire; Mitchell, Jacqueline C.; Kathe, Claudia; Urwin, Hazel; Manser, Catherine; Miller, Christopher C.; Hortobágyi, Tibor; Dragunow, Mike; Rogelj, Boris; Shaw, Christopher E.

    2013-01-01

    Mutations in the gene encoding Fused in Sarcoma (FUS) cause amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. FUS is a predominantly nuclear DNA- and RNA-binding protein that is involved in RNA processing. Large FUS-immunoreactive inclusions fill the perikaryon of surviving motor neurons of ALS patients carrying mutations at post-mortem. This sequestration of FUS is predicted to disrupt RNA processing and initiate neurodegeneration. Here, we demonstrate that C-terminal ALS mutations disrupt the nuclear localizing signal (NLS) of FUS resulting in cytoplasmic accumulation in transfected cells and patient fibroblasts. FUS mislocalization is rescued by the addition of the wild-type FUS NLS to mutant proteins. We also show that oxidative stress recruits mutant FUS to cytoplasmic stress granules where it is able to bind and sequester wild-type FUS. While FUS interacts with itself directly by protein–protein interaction, the recruitment of FUS to stress granules and interaction with PABP are RNA dependent. These findings support a two-hit hypothesis, whereby cytoplasmic mislocalization of FUS protein, followed by cellular stress, contributes to the formation of cytoplasmic aggregates that may sequester FUS, disrupt RNA processing and initiate motor neuron degeneration. PMID:23474818

  12. Physiological effects of fenpropimorph on wild-type Saccharomyces cerevisiae and fenpropimorph-resistant mutants.

    PubMed Central

    Lorenz, R T; Parks, L W

    1991-01-01

    Fenpropimorph-resistant mutants of Saccharomyces cerevisiae were isolated by a gradient selection procedure. The mutants were cross-resistant to other morpholines (fenpropidin, dodemorph, tridemorph) and 15-azasterol, but were susceptible to azoles (miconazole, clotrimazole, ketoconazole) and nystatin. In the absence of fenpropimorph, the major sterol produced by the mutants and the parental strain was ergosterol. In the presence of fenpropimorph, ignosterol (ergosta-8,14-dien-3 beta-ol) was the major sterol produced by the mutants and the parental strain. The resistance to fenpropimorph involves two recessive genes, each of which allows a semiresistance, when they are isolated apart from one another. Strain JR4 (erg3 erg11), which produces 14-methylfecosterol [14 alpha-methyl-ergosta-8,24(28)-dien- 3-beta-ol) as the major sterol in the presence or absence of fenpropimorph, was also found to be resistant to the drug. The growth inhibitory effect of fenpropimorph on wild-type cells appears to be linked to the production of ignosterol. The uptake of exogenous sterol by wild-type cells was greatly enhanced in the presence of fenpropimorph. The growth inhibition caused by fenpropimorph could only be overcome with bulk levels of exogenous C-5,6-unsaturated sterols. PMID:1929324

  13. ALS mutant FUS disrupts nuclear localization and sequesters wild-type FUS within cytoplasmic stress granules.

    PubMed

    Vance, Caroline; Scotter, Emma L; Nishimura, Agnes L; Troakes, Claire; Mitchell, Jacqueline C; Kathe, Claudia; Urwin, Hazel; Manser, Catherine; Miller, Christopher C; Hortobágyi, Tibor; Dragunow, Mike; Rogelj, Boris; Shaw, Christopher E

    2013-07-01

    Mutations in the gene encoding Fused in Sarcoma (FUS) cause amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. FUS is a predominantly nuclear DNA- and RNA-binding protein that is involved in RNA processing. Large FUS-immunoreactive inclusions fill the perikaryon of surviving motor neurons of ALS patients carrying mutations at post-mortem. This sequestration of FUS is predicted to disrupt RNA processing and initiate neurodegeneration. Here, we demonstrate that C-terminal ALS mutations disrupt the nuclear localizing signal (NLS) of FUS resulting in cytoplasmic accumulation in transfected cells and patient fibroblasts. FUS mislocalization is rescued by the addition of the wild-type FUS NLS to mutant proteins. We also show that oxidative stress recruits mutant FUS to cytoplasmic stress granules where it is able to bind and sequester wild-type FUS. While FUS interacts with itself directly by protein-protein interaction, the recruitment of FUS to stress granules and interaction with PABP are RNA dependent. These findings support a two-hit hypothesis, whereby cytoplasmic mislocalization of FUS protein, followed by cellular stress, contributes to the formation of cytoplasmic aggregates that may sequester FUS, disrupt RNA processing and initiate motor neuron degeneration. PMID:23474818

  14. High Pathogenicity of Wild-Type Measles Virus Infection in CD150 (SLAM) Transgenic Mice

    PubMed Central

    Sellin, Caroline I.; Davoust, Nathalie; Guillaume, Vanessa; Baas, Dominique; Belin, Marie-Françoise; Buckland, Robin; Wild, T. Fabian; Horvat, Branka

    2006-01-01

    Measles virus (MV) infection causes an acute childhood disease, associated in certain cases with infection of the central nervous system and development of a severe neurological disease. We have generated transgenic mice ubiquitously expressing the human protein SLAM (signaling lymphocytic activation molecule), or CD150, recently identified as an MV receptor. In contrast to all other MV receptor transgenic models described so far, in these mice infection with wild-type MV strains is highly pathogenic. Intranasal infection of SLAM transgenic suckling mice leads to MV spread to different organs and the development of an acute neurological syndrome, characterized by lethargy, seizures, ataxia, weight loss, and death within 3 weeks. In addition, in this model, vaccine and wild-type MV strains can be distinguished by virulence. Furthermore, intracranial MV infection of adult transgenic mice generates a subclinical infection associated with a high titer of MV-specific antibodies in the serum. Finally, to analyze new antimeasles therapeutic approaches, we created a recombinant soluble form of SLAM and demonstrated its important antiviral activity both in vitro and in vivo. Taken together, our results show the high susceptibility of SLAM transgenic mice to MV-induced neurological disease and open new perspectives for the analysis of the implication of SLAM in the neuropathogenicity of other morbilliviruses, which also use this molecule as a receptor. Moreover, this transgenic model, in allowing a simple readout of the efficacy of an antiviral treatment, provides unique experimental means to test novel anti-MV preventive and therapeutic strategies. PMID:16775330

  15. Molecular dynamics studies on the structural stability of wild-type dog prion protein.

    PubMed

    Zhang, Jiapu; Liu, David D W

    2011-06-01

    Prion diseases such as Creutzfeldt-Jakob disease, variant Creutzfeldt-Jakob diseases, Gerstmann-Sträussler-Scheinker syndrome, Fatal Familial Insomnia, Kuru in humans, scrapie in sheep, bovine spongiform encephalopathy (or 'mad-cow' disease) and chronic wasting disease in cattle are invariably fatal and highly infectious neurodegenerative diseases affecting humans and animals. However, by now there have not been some effective therapeutic approaches to treat all these prion diseases. In 2008, canine mammals including dogs (canis familials) were the first time academically reported to be resistant to prion diseases (Vaccine 26: 2601-2614 (2008)). Thus, it is very worth studying the molecular structures of dog prion protein to obtain insights into the immunity of dogs to prion diseases. This paper studies the molecular structural dynamics of wild-type dog prion protein. The comparison analyses with rabbit prion protein show that the dog prion protein has stable molecular structures whether under neutral or low pH environments. We also find that the salt bridges such as D177-R163 contribute to the structural stability of wild-type rabbit prion protein under neutral pH environment. PMID:21469747

  16. Protein Folding Simulation of Mutant Go Models of the Wild-Type Trp-cage Protein

    NASA Astrophysics Data System (ADS)

    Linhananta, Apichart; Liu, Junmin

    2008-03-01

    For the past three decades, Go models of protein folding have played important roles in the understanding of how proteins fold from random conformations to their unique native structures. Unfortunately Go models reliance on known NMR or x-ray structures to construct Go interaction potentials severely limit their predictive powers. In this work, we introduce a novel method for constructing Go interaction potentials of mutant proteins based on Go interaction potentials of wild type proteins. As a template we employ the all-atom Go model of the 20-residue Trp-cage protein (A. Linhananta, J. Boer and I. MacKay, J. Chem. Phys., 2005, 122, 114901) as the wild type Go model. Trp-cage mutants are constructed by replacing a Trp-cage residue with a different residue. In particular the Pro-12 residue of the Trp-cage is substituted by Trp-12 to produce the Trp2-cage mutant, whose native structure is not yet known. Monte Carlo simulations, using CHARMM force fields, are performed to determine the ground-state structure mutant. The resulting mutant structures are used to construct the Go interaction potential of the Trp2-cage mutant Go model.

  17. Global carbon utilization profiles of wild-type, mutant, and transformant strains of Hypocrea jecorina.

    PubMed

    Druzhinina, Irina S; Schmoll, Monika; Seiboth, Bernhard; Kubicek, Christian P

    2006-03-01

    The ascomycete Hypocrea jecorina (Trichoderma reesei), an industrial producer of cellulases and hemicellulases, can efficiently degrade plant polysaccharides. However, the catabolic pathways for the resulting monomers and their relationship to enzyme induction are not well known. Here we used the Biolog Phenotype MicroArrays technique to evaluate the growth of H. jecorina on 95 carbon sources. For this purpose, we compared several wild-type isolates, mutants producing different amounts of cellulases, and strains transformed with a heterologous antibiotic resistance marker gene. The wild-type isolates and transformed strains had the highest variation in growth patterns on individual carbon sources. The cellulase mutants were relatively similar to their parental strains. Both in the mutant and in the transformed strains, the most significant changes occurred in utilization of xylitol, erythritol, D-sorbitol, D-ribose, D-galactose, L-arabinose, N-acetyl-D-glucosamine, maltotriose, and beta-methyl-glucoside. Increased production of cellulases was negatively correlated with the ability to grow on gamma-aminobutyrate, adonitol, and 2-ketogluconate; and positively correlated with that on d-sorbitol and saccharic acid. The reproducibility, relative simplicity, and high resolution (+/-10% of increase in mycelial density) of the phenotypic microarrays make them a useful tool for the characterization of mutant and transformed strains and for a global analysis of gene function. PMID:16517662

  18. Wild-type macrophages reverse disease in heme oxygenase 1-deficient mice.

    PubMed

    Kovtunovych, Gennadiy; Ghosh, Manik C; Ollivierre, Wade; Weitzel, R Patrick; Eckhaus, Michael A; Tisdale, John F; Yachie, Akihiro; Rouault, Tracey A

    2014-08-28

    Loss-of-function mutation in the heme oxygenase 1 (Hmox1) gene causes a rare and lethal disease in children, characterized by severe anemia and intravascular hemolysis, with damage to endothelia and kidneys. Previously, we found that macrophages engaged in recycling of red cells were depleted from the tissues of Hmox1(-/-) mice, which resulted in intravascular hemolysis and severe damage to the endothelial system, kidneys, and other organs. Here, we report that subablative bone marrow transplantation (BMT) has a curative effect for disease in Hmox1(-/-) animals as a result of restoration of heme recycling by repopulation of the tissues with wild-type macrophages. Although engraftment was transient, BMT reversed anemia, normalized blood chemistries and iron metabolism parameters, and prevented renal damage. The largest proportion of donor-derived cells was observed in the livers of transplanted animals. These cells, identified as Kupffer cells with high levels of Hmox1 expression, persisted months after transient engraftment of the donor bone marrow and were responsible for the full restoration of heme-recycling ability in Hmox1(-/-) mice and reversing Hmox1-deficient phenotype. Our findings suggest that BMT or the development of specific cell therapies to repopulate patients' tissues with wild-type or reengineered macrophages represent promising approaches for HMOX1 deficiency treatment in humans. PMID:24963040

  19. Gravitropism of hypocotyls of wild-type and starch-deficient Arabidopsis seedlings in spaceflight studies

    NASA Technical Reports Server (NTRS)

    Kiss, J. Z.; Edelmann, R. E.; Wood, P. C.

    1999-01-01

    The major purpose of this spaceflight project was to investigate the starch-statolith hypothesis for gravity perception, and a secondary goal was to study plant growth and development under spaceflight conditions. This research was based on our ground studies of gravity perception in the wild type and three starch-deficient (one starchless and two reduced starch) mutants of Arabidopsis thaliana (L.) Heynh. Dark-grown seedlings that developed in microgravity were given one of several (30 min, 60 min, or 90 min) 1-g stimuli by an on-board centrifuge, and additional controls for seedling development also were performed. These latter control experiments included a morphological study of plants that developed in space in microgravity (F microg), in space on a centrifuge (F 1g), on the ground (G 1g), and on a rotating clinostat on the ground. Since elevated levels of ethylene were reported in the spacecraft atmosphere, additional controls for morphology and gravitropism with added ethylene also were performed. While exogenous ethylene reduced the absolute magnitude of the response in all four strains of Arabidopsis, this gas did not appear to change the relative graviresponsiveness among the strains. The relative response of hypocotyls of microgravity-grown seedlings to the stimuli provided by the in-flight centrifuge was: wild type > starch-deficient mutants. Although the protoplast pressure model for gravity perception cannot be excluded, these results are consistent with a statolith-based model for perception in plants.

  20. Plastid sedimentation kinetics in roots of wild-type and starch-deficient mutants of Arabidopsis

    NASA Technical Reports Server (NTRS)

    MacCleery, S. A.; Kiss, J. Z.

    1999-01-01

    Sedimentation and movement of plastids in columella cells of the root cap were measured in seedlings of wild-type, a reduced starch mutant, and a starchless mutant of Arabidopsis. To assay for sedimentation, we used both linear measurements and the change of angle from the cell center as indices in vertical and reoriented plants with the aid of computer-assisted image analysis. Seedlings were fixed at short periods after reorientation, and plastid sedimentation correlated with starch content in the three strains of Arabidopsis. Amyloplasts of wild-type seedlings showed the greatest sedimentation, whereas plastids of the starchless mutant showed no significant sedimentation in the vertically grown and reoriented seedlings. Because previous research has shown that a full complement of starch is needed for full gravitropic sensitivity, this study correlates increased sensitivity with plastid sedimentation. However, although plastid sedimentation contributed to gravisensitivity, it was not required, because the gravitropic starchless mutant had plastids that did not sediment. This is the first study, to our knowledge, to measure plastid sedimentation in Arabidopsis roots after reorientation of seedlings. Taken together, the results of this study are consistent with the classic plastid-based and protoplast-based models of graviperception and suggest that multiple systems of perception exist in plant cells.

  1. Comparative metabolic profiling of mce1 operon mutant vs wild-type Mycobacterium tuberculosis strains.

    PubMed

    Queiroz, Adriano; Medina-Cleghorn, Daniel; Marjanovic, Olivera; Nomura, Daniel K; Riley, Lee W

    2015-11-01

    Mycobacterium tuberculosis disrupted in a 13-gene operon (mce1) accumulates free mycolic acids (FM) in its cell wall and causes accelerated death in mice. Here, to more comprehensively analyze differences in their cell wall lipid composition, we used an untargeted metabolomics approach to compare the lipid profiles of wild-type and mce1 operon mutant strains. By liquid chromatography-mass spectrometry, we identified >400 distinct lipids significantly altered in the mce1 mutant compared to wild type. These lipids included decreased levels of saccharolipids and glycerophospholipids, and increased levels of alpha-, methoxy- and keto mycolic acids (MA), and hydroxyphthioceranic acid. The mutant showed reduced expression of mmpL8, mmpL10, stf0, pks2 and papA2 genes involved in transport and metabolism of lipids recognized to induce proinflammatory response; these lipids were found to be decreased in the mutant. In contrast, the transcripts of mmpL3, fasI, kasA, kasB, acpM and RV3451 involved in MA transport and metabolism increased; MA inhibits inflammatory response in macrophages. Since the mce1 operon is known to be regulated in intracellular M. tuberculosis, we speculate that the differences we observed in cell wall lipid metabolism and composition may affect host response to M. tuberculosis infection and determine the clinical outcome of such an infection. PMID:26319139

  2. Combined effect of temperature and zinc on Caenorhabditis elegans wild type and daf-21 mutant strains.

    PubMed

    Wang, Yunbiao; Ezemaduka, Anastasia N

    2014-04-01

    Heavy metal pollution in aquatic ecosystems is a far reaching environmental problem. The possible influences of heavy metal exposure and the potential harm to organisms when combined with other environmental stressors such as temperature have been largely unexplored. An aquatic toxicity test of Caenorhabditis elegans was performed to estimate the 24h median lethal concentration (LC50) of different zinc concentrations at different temperatures (15°C, 20°C, 25°C, and 30°C). We also examined the time course thermotolerance on wild type (N2) and daf-21 null (JT6130) adults exposed to 6.1mM zinc at 37°C. Hsp90 protein expression level in response to the combined effect of temperature and zinc toxicity was also investigated by both Western blots and ELISA. Our results show that C. elegans wild type nematodes exhibit severe lethal toxicity after a 24h exposure to zinc at higher temperatures. In addition, the expression level of Hsp90 was highly inhibited in adult worms subjected to zinc stress. This toxicity assay at different temperatures provides insight into organism response to combined effects of temperature and zinc toxicity. PMID:24679967

  3. Elucidation of the atherosclerotic disease process in apo E and wild type mice by vibrational spectroscopy

    NASA Astrophysics Data System (ADS)

    Adar, Fran; Jelicks, Linda; Naudin, Coralie; Rousseau, Denis; Yeh, Syun-ru

    2004-07-01

    Raman and FTIR microprobe spectroscopy have been used to characterize the atherosclerotic process in Apo E and wild type mice. The Apo E null mouse is being studied in parallel with a healthy strain as a model of the human atherosclerotic disease. Preliminary Raman microprobe spectra have been recorded from the lumen of the aorta vessels from a normal black mouse (C57BL/6J) and the apo E null mouse fed on a normal chow diet. Spectra were also recorded from another normal mouse fed breeder chow containing a much higher content of fats. In the Raman spectra the fat cells exhibited spectra typical of esterified triglycerides while the wall tissue had spectra dominated by Amide I and III modes and the phenylalanine stretch at 1003 cm-1 of protein. The FTIR spectra showed the typical Amide I and II bands of protein and the strong >C=O stretch of the triglycerides. In addition, there were morphologically distinct regions of the specimens indicating a surprising form of calcification in one very old mouse (wild type), and free fatty acid inclusions in the knock out mouse. The observation of these chemistries provide new information for elucidation of the molecular mechanisms of the development of atherosclerosis.

  4. Retinal ganglion cell responses to voltage and current stimulation in wild-type and rd1 mouse retinas

    NASA Astrophysics Data System (ADS)

    Goo, Yong Sook; Ye, Jang Hee; Lee, Seokyoung; Nam, Yoonkey; Ryu, Sang Baek; Kim, Kyung Hwan

    2011-06-01

    Retinal prostheses are being developed to restore vision for those with retinal diseases such as retinitis pigmentosa or age-related macular degeneration. Since neural prostheses depend upon electrical stimulation to control neural activity, optimal stimulation parameters for successful encoding of visual information are one of the most important requirements to enable visual perception. In this paper, we focused on retinal ganglion cell (RGC) responses to different stimulation parameters and compared threshold charge densities in wild-type and rd1 mice. For this purpose, we used in vitro retinal preparations of wild-type and rd1 mice. When the neural network was stimulated with voltage- and current-controlled pulses, RGCs from both wild-type and rd1 mice responded; however the temporal pattern of RGC response is very different. In wild-type RGCs, a single peak within 100 ms appears, while multiple peaks (approximately four peaks) with ~10 Hz rhythm within 400 ms appear in RGCs in the degenerated retina of rd1 mice. We find that an anodic phase-first biphasic voltage-controlled pulse is more efficient for stimulation than a biphasic current-controlled pulse based on lower threshold charge density. The threshold charge densities for activation of RGCs both with voltage- and current-controlled pulses are overall more elevated for the rd1 mouse than the wild-type mouse. Here, we propose the stimulus range for wild-type and rd1 retinas when the optimal modulation of a RGC response is possible.

  5. DDX3 enhances oncogenic KRAS-induced tumor invasion in colorectal cancer via the β-catenin/ZEB1 axis

    PubMed Central

    Wu, De-Wei; Lin, Po-Lin; Cheng, Ya-Wen; Huang, Chi-Chou; Wang, Lee; Lee, Huei

    2016-01-01

    DDX3 plays a dual role in colorectal cancer; however, the role and underlying mechanism of DDX3 in colorectal tumorigenesis remains unclear. Here, we provide evidence that DDX3 enhances oncogenic KRAS transcription via an increase in SP1 binding to its promoter. Accelerating oncogenic KRAS expression by DDX3 promotes the invasion capability via the ERK/PTEN/AKT/β-catenin cascade. Moreover, the β-catenin/ZEB1 axis is responsible for DDX3-induced cell invasiveness and xenograft lung tumor nodule formation. The xenograft lung tumor nodules induced by DDX3-overexpressing T84 stable clone were nearly suppressed by the inhibitor of AKT (perifosine) or β-catenin (XAV939). Among patients, high KRAS, positive nuclear β-catenin expression and high ZEB1 were more commonly occurred in high-DDX3 tumors than in low-DDX3 tumors. High-DDX3, high-KRAS, positive nuclear β-catenin tumors, and high-ZEB1 exhibited worse overall survival (OS) and relapse free survival (RFS) than their counterparts. In conclusion, DDX3 may play an oncogenic role to promote tumor growth and invasion in colon cancer cells via the β-catenin/ZEB1 axis due to increasing KRAS transcription. We therefore suggest that AKT or β-catenin may potentially act as a therapeutic target to improve tumor regression and outcomes in colorectal cancer patients who harbored high-DDX3 tumors. PMID:27007150

  6. Early recognition of lung cancer by integrin targeted imaging in K-ras mouse model.

    PubMed

    Ermolayev, Vladimir; Mohajerani, Pouyan; Ale, Angelique; Sarantopoulos, Athanasios; Aichler, Michaela; Kayser, Gian; Walch, Axel; Ntziachristos, Vasilis

    2015-09-01

    Non-small cell lung cancer is characterized by slow progression and high heterogeneity of tumors. Integrins play an important role in lung cancer development and metastasis and were suggested as a tumor marker; however their role in anticancer therapy remains controversial. In this work, we demonstrate the potential of integrin-targeted imaging to recognize early lesions in transgenic mouse model of lung cancer based on spontaneous introduction of mutated human gene bearing K-ras mutation. We conducted ex vivo and fluorescence molecular tomography-X-ray computed tomography (FMT-XCT) in vivo imaging and analysis for specific targeting of early lung lesions and tumors in rodent preclinical model for lung cancer. The lesions and tumors were characterized by histology, immunofluorescence and immunohistochemistry using a panel of cancer markers. Ex vivo, the integrin-targeted fluorescent signal significantly differed between wild type lung tissue and K-ras pulmonary lesions (PL) at all ages studied. The panel of immunofluorescence experiments demonstrated that PL, which only partially show cancer cell features were detected by αvβ3-integrin targeted imaging. Human patient material analysis confirmed the specificity of target localization in different lung cancer types. Most importantly, small tumors in the lungs of 4-week-old animals could be noninvasively detected in vivo on the fluorescence channel of FMT-XCT. Our findings demonstrated αvβ3-integrin targeted fluorescent imaging to specifically detect premalignant pleural lesions in K-ras mice. Integrin targeted imaging may find application areas in preclinical research and clinical practice, such as early lung cancer diagnostics, intraoperative assistance or therapy monitoring. PMID:25450481

  7. Let-7 microRNA-binding-site polymorphism in the 3′UTR of KRAS and colorectal cancer outcome: a systematic review and meta-analysis

    PubMed Central

    Langevin, Scott M; Christensen, Brock C

    2014-01-01

    There is a small but growing body of literature regarding the predictive utility of a Let-7 microRNA-binding-site polymorphism in the 3′-untranslated region (UTR) of KRAS (KRAS-LCS6) for colorectal cancer outcome, although the results are conflicting. We performed a review and meta-analysis in an attempt to better clarify this relationship. A PubMed search was conducted to identify all studies reporting on KRAS let-7 microRNA-binding site polymorphism (LCS6; rs61764370) and colorectal cancer outcome. Hazard ratios (HR) and corresponding 95% confidence intervals (CI) were extracted or estimated from each manuscript. Log HRs and log CIs were combined across studies using the inverse-variance weight to calculate fixed- and random-effects summary estimates and corresponding 95% CIs for overall and progression-free survival. We did not observe any significant association between overall or progression-free survival, neither when considering all colorectal cancer patients nor for subgroup analyses (metastatic, anti-EGFR [epidermal growth factor receptor] treatment, or KRAS wild type). There was substantial heterogeneity across studies, overall and among subgroups analyzed. We have found no clear evidence to support an association between the KRAS-LCS6 genotype and overall or progression-free survival among colorectal cancer patients, even after conducting subgroup analyses by stage and anti-EGFR treatment status. This information helps to clarify the confusing body of literature regarding the clinical implications of the KRAS-LCS6 genetic variant on colorectal cancer outcomes, indicating that it should not be used at the present time to personalize therapeutic strategies (PROSPERO registration number: CRD42013005325). PMID:24890702

  8. Downregulation of Microrna-126 Contributes to Tumorigenesis of Squamous Tongue Cell Carcinoma via Targeting KRAS

    PubMed Central

    Han, Jingying; Wang, Lina; Wang, Xiaofeng; Li, Kun

    2016-01-01

    Background miR-126 has been reported to be differentially expressed in various malignancies, whereas its role in the pathogenesis of tongue squamous cell carcinoma (TSCC) remains largely unknown. Material/Methods In this study, we collected 21 pairs of TSCC cancerous and adjacent non-cancerous tissue samples, with which we performed real-time PCR to determine and compare the expression of 6 candidate miRNAs that are reportedly associated with tumorigenesis of TSCC, including miR-100, miR-451, miR-221, let-7a, miR-21, and miR-126. We further performed luciferase assay to validate KRAS as a target of miR-126, and conducted transfection to study the effect of miR-126 on proliferation and apoptosis of the cells. Results We identified that miR-126 was significantly downregulated in the cancerous tissue samples compared with the non-cancerous control tissue samples. By using computational analysis, we identified that KRAS is a virtual target of miR-126, and such association was verified by using luciferase assay. In addition, we found that mRNA and protein expression level of KRAS was significantly higher in the tumor tissue than the control tissue samples. Conclusions The following in vitro experiment showed that both mRNA and protein KRAS expression were significantly decreased in SCC-15 cells in which miR-126 was overexpressed, in comparison with similar cells transfected with a negative control, while downregulation of miR-126 by transfecting the cells with miR-126 inhibitors significantly upregulated the mRNA and protein expression of KRAS. Conclusions: miR-126 might be a promising diagnostic and therapeutic target in the prevention and management of TSCC patients. PMID:26883054

  9. ReadMax-a novel reading and scoring approach for EGFR gene copy number to predict therapeutic benefit of erlotinib treatment in EGFR wild-type non-small-cell lung cancer.

    PubMed

    Moecks, Joachim; Soulières, Denis; Klughammer, Barbara

    2015-07-01

    EGFR mutation testing is now well established as a means of selecting the optimal first-line therapy for patients with advanced non-small-cell lung cancer (NSCLC). However, deciding on the correct treatment for EGFR wild-type NSCLC remains a challenge. EGFR fluorescence in-situ hybridization (FISH) testing of gene copy number has been a promising marker, but has provided mixed results despite attempts to standardize the reading and scoring process. The novel ReadMax reading and scoring system focuses on the most aberrant cells, to identify oncogene addiction, rather than taking a representative reading as in the Colorado method. The methodology was developed using historical samples from the TRUST and MERIT studies, followed by re-reading of the samples from the SATURN trial. Analysis of samples using the ReadMax methodology revealed that progression-free survival (PFS) and overall survival (OS) were improved in patients with ReadMax FISH-positive (RM FISH+) tumours, compared with those whose tumours were not RM FISH+: PFS hazard ratios (HRs) were 0.52 for RM FISH+ versus 0.93 for not RM FISH+; OS HRs were 0.69 and 0.92, respectively. For PFS, HR for RM FISH+ versus not RM FISH+ in the SATURN erlotinib group was 0.53 (p = 0.003). The PFS and OS results were also similar in the EGFR wild-type population (PFS HRs were 0.63 and 0.96; OS HRs were 0.61 and 0.84, respectively), although amplification of the EGFR gene in patients with EGFR wild-type disease was not found to be predictive of treatment outcomes, which was unexpected but not unprecedented. KRAS status was not found to affect outcomes. Further experience is required to refine the ReadMax methodology and fully establish its validity and robustness. In conclusion, the ReadMax scoring system to identify patients with EGFR FISH-positive NSCLC is a promising technique, which could improve treatment options and outcomes for patients with advanced NSCLC, in particular for EGFR wild-type tumours. PMID:27499899

  10. GATA2 is epigenetically repressed in human and mouse lung tumors and is not requisite for survival of KRAS mutant lung cancer

    PubMed Central

    Tessema, Mathewos; Yingling, Christin M.; Snider, Amanda M.; Do, Kieu; Juri, Daniel E.; Picchi, Maria A.; Zhang, Xiequn; Liu, Yushi; Leng, Shuguang; Tellez, Carmen S.; Belinsky, Steven A.

    2014-01-01

    Introduction GATA2 was recently described as a critical survival factor and therapeutic target for KRAS mutant non-small cell lung cancer (NSCLC). However, whether this role is affected by epigenetic repression of GATA2 in lung cancer is unclear. Methods GATA2 expression and promoter CpG island methylation were evaluated using human and mouse NSCLC cell lines and tumor-normal pairs. In vitro assays were used to study GATA2 repression on cell survival and during tobacco carcinogen-induced transformation. Results GATA2 expression in KRAS wild-type (n=15) and mutant (n=10) NSCLC cell lines and primary lung tumors (n=24) was significantly lower, 1.3–33.6-fold (p=2.2×10−9), compared to corresponding normal lung. GATA2 promoter was unmethylated in normal lung (0/10) but frequently methylated in lung tumors (96%, 159/165) and NSCLC cell lines (97%, 30/31). This highly prevalent aberrant methylation was independently validated using TCGA data for 369 NSCLC tumor-normal pairs. In vitro studies using an established carcinogen-induced pre-malignancy model revealed that GATA2 expression was initially repressed by chromatin remodeling followed by cytosine methylation during transformation. Similarly, expression of Gata2 in NNK-induced mouse lung tumors (n=6) and cell lines (n=5) was 5-fold and 100-fold lower, respectively, than normal mouse lung. Finally, siRNA-mediated knockdown of GATA2 in KRAS mutant [human (n=4) and murine (n=5)] and wild-type [human (n=4)] NSCLC cell lines showed that further reduction of expression (up to 95%) does not induce cell death. Conclusion GATA2 is epigenetically repressed in human and mouse lung tumors and its further inhibition is not a valid therapeutic strategy for KRAS mutant lung cancer. PMID:24807155

  11. KRAS Mutation Status and Clinical Outcome of Preoperative Chemoradiation With Cetuximab in Locally Advanced Rectal Cancer: A Pooled Analysis of 2 Phase II Trials

    SciTech Connect

    Kim, Sun Young; Shim, Eun Kyung; Yeo, Hyun Yang; Baek, Ji Yeon; Hong, Yong Sang; Kim, Dae Yong; Kim, Tae Won; Kim, Jee Hyun; Im, Seock-Ah; Jung, Kyung Hae; Chang, Hee Jin

    2013-01-01

    Purpose: Cetuximab-containing chemotherapy is known to be effective for KRAS wild-type metastatic colorectal cancer; however, it is not clear whether cetuximab-based preoperative chemoradiation confers an additional benefit compared with chemoradiation without cetuximab in patients with locally advanced rectal cancer. Methods and Materials: We analyzed EGFR, KRAS, BRAF, and PIK3CA mutation status with direct sequencing and epidermal growth factor receptor (EGFR) and Phosphatase and tensin homolog (PTEN) expression status with immunohistochemistry in tumor samples of 82 patients with locally advanced rectal cancer who were enrolled in the IRIX trial (preoperative chemoradiation with irinotecan and capecitabine; n=44) or the ERBIRIX trial (preoperative chemoradiation with irinotecan and capecitabine plus cetuximab; n=38). Both trials were similarly designed except for the administration of cetuximab; radiation therapy was administered at a dose of 50.4 Gy/28 fractions and irinotecan and capecitabine were given at doses of 40 mg/m{sup 2} weekly and 1650 mg/m{sup 2}/day, respectively, for 5 days per week. In the ERBIRIX trial, cetuximab was additionally given with a loading dose of 400 mg/m{sup 2} on 1 week before radiation, and 250 mg/m{sup 2} weekly thereafter. Results: Baseline characteristics before chemoradiation were similar between the 2 trial cohorts. A KRAS mutation in codon 12, 13, and 61 was noted in 15 (34%) patients in the IRIX cohort and 5 (13%) in the ERBIRIX cohort (P=.028). Among 62 KRAS wild-type cancer patients, major pathologic response rate, disease-free survival and pathologic stage did not differ significantly between the 2 cohorts. No mutations were detected in BRAF exon 11 and 15, PIK3CA exon 9 and 20, or EGFR exon 18-24 in any of the 82 patients, and PTEN and EGFR expression were not predictive of clinical outcome. Conclusions: In patients with KRAS wild-type locally advanced rectal cancer, the addition of cetuximab to the chemoradiation with

  12. Transcript profiling reveals expression differences in wild-type and glabrous soybean lines

    PubMed Central

    2011-01-01

    Background Trichome hairs affect diverse agronomic characters such as seed weight and yield, prevent insect damage and reduce loss of water but their molecular control has not been extensively studied in soybean. Several detailed models for trichome development have been proposed for Arabidopsis thaliana, but their applicability to important crops such as cotton and soybean is not fully known. Results Two high throughput transcript sequencing methods, Digital Gene Expression (DGE) Tag Profiling and RNA-Seq, were used to compare the transcriptional profiles in wild-type (cv. Clark standard, CS) and a mutant (cv. Clark glabrous, i.e., trichomeless or hairless, CG) soybean isoline that carries the dominant P1 allele. DGE data and RNA-Seq data were mapped to the cDNAs (Glyma models) predicted from the reference soybean genome, Williams 82. Extending the model length by 250 bp at both ends resulted in significantly more matches of authentic DGE tags indicating that many of the predicted gene models are prematurely truncated at the 5' and 3' UTRs. The genome-wide comparative study of the transcript profiles of the wild-type versus mutant line revealed a number of differentially expressed genes. One highly-expressed gene, Glyma04g35130, in wild-type soybean was of interest as it has high homology to the cotton gene GhRDL1 gene that has been identified as being involved in cotton fiber initiation and is a member of the BURP protein family. Sequence comparison of Glyma04g35130 among Williams 82 with our sequences derived from CS and CG isolines revealed various SNPs and indels including addition of one nucleotide C in the CG and insertion of ~60 bp in the third exon of CS that causes a frameshift mutation and premature truncation of peptides in both lines as compared to Williams 82. Conclusion Although not a candidate for the P1 locus, a BURP family member (Glyma04g35130) from soybean has been shown to be abundantly expressed in the CS line and very weakly expressed in the

  13. Implication of K-ras and p53 in colorectal cancer carcinogenesis in Tunisian population cohort.

    PubMed

    Ines, Chaar; Donia, Ounissi; Rahma, Boughriba; Ben Ammar, Azza; Sameh, Amara; Khalfallah, Taher; Abdelmajid, Ben Hmida; Sabeh, Mzabi; Saadia, Bouraoui

    2014-07-01

    According to the multistep route of genetic alterations in the colorectal adenoma-carcinoma sequence, the complex K-ras/p53 mutation is one of the first alterations to occur and represent an important genetic event in colorectal cancer (CRC). An evaluation of the mutation spectra in K-ras and p53 gene was effected in 167 Tunisian patients with sporadic CRC to determine whether our populations have similar pattern of genetic alteration as in Maghrebin's population. Mutation patterns of codon 12-13 of K-ras and exon 5-8 of p53 were analyzed by immunohistochemistry and PCR-SSCP and confirmed by sequencing. Mutations in the K-ras gene were detected in 31.13 % and affect the women more than the men (p = 0.008). Immunostaining showed that expression of p21 ras was correlated with the advanced age (p = 0.004), whereas loss of signal was associated with mucinous histotype (p = 0.003). Kaplan-Meier survival curve found that patients with the K-ras mutation had a shorter survival compared with patients without mutation (p = 0.005). Alteration in p53 was seen in 17.4 % of patients and affects three hot spot codons such as 175, 245, and 248. Overexpression of p53 was seen in 34.1 % and correlated with tumor node metastasis (TNM) advanced stage (p = 0.037) and mucinous histotype (p = 0.001). A high concordance between p53 expression and alteration (p<0.005) was shown. Concomitant mutations in K-ras and p53 gene were detected in only 4 % of tumors. K-ras and p53 undergo separate pathways in colorectal tumorogenesis. Interestingly, mutations in the K-ras gene might be considered a valuable prognostic factor correlated to poor outcome. p53 gene alterations were rather low in our set, and methylation pattern of p53 is required to elucidate the molecular basis of this protein in CRC. PMID:24763823

  14. Differential regulation of insulin-like growth factor-I receptor gene expression by wild type and mutant androgen receptor in prostate cancer cells.

    PubMed

    Schayek, Hagit; Seti, Hila; Greenberg, Norman M; Sun, Shihua; Werner, Haim; Plymate, Stephen R

    2010-07-29

    The progression of prostate cancer from an organ-confined, androgen-sensitive disease to a metastatic one is associated with dysregulation of androgen receptor (AR)-regulated target genes and with a decrease in insulin-like growth factor-I receptor (IGF-IR) expression. To investigate the differential effects of wild type (wt) and mutant AR on IGF-IR levels we employed a series of isogenic prostate-derived cell lines and human xenografts. We show that basal and phosphorylated IGF-IR levels progressively decreased as prostate cancer cells became more tumorigenic and metastatic. In addition, we show that wt, but not mutant, AR along with dihydrotestosterone treatment increased IGF-IR promoter activity and endogenous IGF-IR levels. ChIP analysis show enhanced AR binding to the IGF-IR promoter in AR-overexpressing cells. Finally, wt AR-overexpressing cells display an enhanced proliferation rate. In summary, we provide evidence that activated wt AR enhances IGF-IR transcription in prostate cancer cells via a mechanism that involves AR binding to the IGF-IR promoter. AR mutations alter the ability of the mutated protein to regulate IGF-IR expression. Our results suggest that prostate cancer progression is associated with a decrease in IGF-IR expression that could be the result of impaired ability of AR to stimulate IGF-IR gene expression. PMID:20417685

  15. MicroRNA-128-3p impaired water maze learning by suppressing Doublecortin expression in both wild type and Aβ-42 infused mice.

    PubMed

    Chen, Jinlong; Li, Wen; Li, Yuan; He, Songwei; Li, Lingyu; Liang, Lining; Song, Yancheng; Qin, Dajiang; Zheng, Hui

    2016-07-28

    MicroRNA-128-3p (miR-128) is a brain-enriched microRNA reported to target Doublecortin (Dcx), a key transcriptional factor during adult neurogenesis. However, the downstream physiological effects of this miR-128-DCX axis remain unclear. Here we demonstrated that miR-128 could suppress Dcx expression by complementally binding to the -849 to -856 region of the 3'UTR of mouse Dcx. During differentiation of neural stem cells, over-expressing miR-128 with a lentivirus system inhibited the up-regulation of Dcx on Day 5, subsequently decreasing the percentage of TuJ+ cells on Day 16. Administration of the lentivirus encoding miR-128 into mouse hippocampi significantly impaired water maze learning after 14days, which could be attenuated when the Dcx-encoding virus was delivered simultaneously. In addition, similar changes including miR-128 up-regulation, Dcx down-regulation and learning defects were observed after a 14-day infusion of Aβ-42, which were also partially reversed by over-expressing Dcx. Collectively, the regulation axis from miR-128 to Dcx is critical for hippocampus-related contextual learning not only in wild type, but also in mice infused with Aβ-42. PMID:27222923

  16. Protective role of olesoxime against wild-type α-synuclein-induced toxicity in human neuronally differentiated SHSY-5Y cells

    PubMed Central

    Gouarné, C; Tracz, J; Paoli, M Giraudon; Deluca, V; Seimandi, M; Tardif, G; Xilouri, M; Stefanis, L; Bordet, T; Pruss, R M

    2015-01-01

    BACKGROUND AND PURPOSE Parkinson's disease (PD) is usually diagnosed clinically from classical motor symptoms, while definitive diagnosis is made postmortem, based on the presence of Lewy bodies and nigral neuron cell loss. α-Synuclein (ASYN), the main protein component of Lewy bodies, clearly plays a role in the neurodegeneration that characterizes PD. Additionally, mutation in the SNCA gene or copy number variations are associated with some forms of familial PD. Here, the objective of the study was to evaluate whether olesoxime, a promising neuroprotective drug can prevent ASYN-mediated neurotoxicity. EXPERIMENTAL APPROACH We used here a novel, mechanistically approachable and attractive cellular model based on the inducible overexpression of human wild-type ASYN in neuronally differentiated human neuroblastoma (SHSY-5Y) cells. This model demonstrates gradual cellular degeneration, coinciding temporally with the appearance of soluble and membrane-bound ASYN oligomers and cell death combining both apoptotic and non-apoptotic pathways. KEY RESULTS Olesoxime fully protected differentiated SHSY-5Y cells from cell death, neurite retraction and cytoplasmic shrinkage induced by moderate ASYN overexpression. This protection was associated with a reduction in cytochrome c release from mitochondria and caspase-9 activation suggesting that olesoxime prevented ASYN toxicity by preserving mitochondrial integrity and function. In addition, olesoxime displayed neurotrophic effects on neuronally differentiated SHSY-5Y cells, independent of ASYN expression, by promoting their differentiation. CONCLUSIONS AND IMPLICATIONS Because ASYN is a common underlying factor in many cases of PD, olesoxime could be a promising therapy to slow neurodegeneration in PD. PMID:25220617

  17. Comparation of enhanced green fluorescent protein gene transfected and wild-type porcine neural stem cells.

    PubMed

    Zheng, Yue-Mao; An, Zhi-Xing; Zhao, Xiao-E; Quan, Fu-Sheng; Zhao, Hui-Ying; Zhang, Ya-Rong; Liu, Jun; He, Xiao-Ying; He, Xiao-Ning

    2010-02-01

    The aim of this study was to transfect and express the enhanced green fluorescence protein (EGFP) gene into porcine neural stem cells (NSCs) to determine whether EGFP can be used as a marker to monitor NSCs. NSCs were isolated from embryonic day 30 fetal pig brain and transfected with EGFP gene using lipofection. Transfected and wild-type NSCs were induced to differentiate into cells of neuronal and myogenic lineages. Markers of passage three NSCs and their differentiated cells were tested by reverse transcription polymerase chain reaction. The results showed that EGFP could be expressed in NSCs and the differentiated cells. NSCs expressed Nestin, NogoA, DCX, Hes1, Oct4, CD-90 and Sox2. NSCs could differentiated into astrocyte (GFAP(+)), oligodendrocyte (GalC(+)), neuron (NF(+), NSE(+) and MAP2(+)) and myocyte (myf-6(+) and myoD(+)). We concluded that EGFP can be used as a marker in monitoring NSCs. PMID:19580981

  18. Genome sequence of SG33 strain and recombination between wild-type and vaccine myxoma viruses.

    PubMed

    Camus-Bouclainville, Christelle; Gretillat, Magalie; Py, Robert; Gelfi, Jacqueline; Guérin, Jean Luc; Bertagnoli, Stéphane

    2011-04-01

    Myxomatosis in Europe is the result of the release of a South America strain of myxoma virus in 1952. Several attenuated strains with origins in South America or California have since been used as vaccines in the rabbit industry. We sequenced the genome of the SG33 myxoma virus vaccine strain and compared it with those of other myxoma virus strains. We show that SG33 genome carries a large deletion in its right end. Furthermore, our data strongly suggest that the virus isolate from which SG33 is derived results from an in vivo recombination between a wild-type South America (Lausanne) strain and a California MSD-derived strain. These findings raise questions about the use of insufficiently attenuated virus in vaccination. PMID:21470452

  19. The Phenotypic Effects of Royal Jelly on Wild-Type D. melanogaster Are Strain-Specific

    PubMed Central

    Morgan, Stefanie L.; Seggio, Joseph A.; Hicks, Jasmin A.; Sharp, Katherine A.; Axelrod, Jeffrey D.; Wang, Kevin C.

    2016-01-01

    The role for royal jelly (RJ) in promoting caste differentiation of honeybee larvae into queens rather than workers is well characterized. A recent study demonstrated that this poorly understood complex nutrition drives strikingly similar phenotypic effects in Drosophila melanogaster, such as increased body size and reduced developmental time, making possible the use of D. melanogaster as a model system for the genetic analysis of the cellular mechanisms underlying RJ and caste differentiation. We demonstrate here that RJ increases the body size of some wild-type strains of D. melanogaster but not others, and report significant delays in developmental time in all flies reared on RJ. These findings suggest that cryptic genetic variation may be a factor in the D. melanogaster response to RJ, and should be considered when attempting to elucidate response mechanisms to environmental changes in non-honeybee species. PMID:27486863

  20. Cholesterol Secosterol Aldehydes Induce Amyloidogenesis and Dysfunction of Wild Type Tumor Protein p53

    PubMed Central

    Nieva, Jorge; Song, Byeong-Doo; Rogel, Joseph K.; Kujawara, David; Altobel, Lawrence; Izharrudin, Alicia; Boldt, Grant E.; Grover, Rajesh K.; Wentworth, Anita D.; Wentworth, Paul

    2011-01-01

    SUMMARY Epidemiologic and clinical evidence points to an increased risk of cancer when coupled with chronic inflammation. However, the molecular mechanisms that underpin this interrelationship remain largely unresolved. Herein we show that the inflammation-derived cholesterol 5,6-secosterol aldehydes, atheronal-A (KA) and –B (ALD), but not the PUFA-derived aldehydes 4-hydroxynonenal (HNE) and 4-hydroxyhexenal (HHE), induce misfolding of wild-type p53 into an amyloidogenic form that binds thioflavin T and Congo Red dyes but cannot bind to a consensus DNA sequence. Treatment of lung carcinoma cells with KA and ALD leads to a loss of function of extracted p53, as determined by analysis of extracted nuclear protein and in activation of p21. Our results uncover a plausible chemical link between inflammation and cancer and expands the already pivotal role of p53 dysfunction and cancer risk. PMID:21802012

  1. The Phenotypic Effects of Royal Jelly on Wild-Type D. melanogaster Are Strain-Specific.

    PubMed

    Morgan, Stefanie L; Seggio, Joseph A; Nascimento, Nara F; Huh, Dana D; Hicks, Jasmin A; Sharp, Katherine A; Axelrod, Jeffrey D; Wang, Kevin C

    2016-01-01

    The role for royal jelly (RJ) in promoting caste differentiation of honeybee larvae into queens rather than workers is well characterized. A recent study demonstrated that this poorly understood complex nutrition drives strikingly similar phenotypic effects in Drosophila melanogaster, such as increased body size and reduced developmental time, making possible the use of D. melanogaster as a model system for the genetic analysis of the cellular mechanisms underlying RJ and caste differentiation. We demonstrate here that RJ increases the body size of some wild-type strains of D. melanogaster but not others, and report significant delays in developmental time in all flies reared on RJ. These findings suggest that cryptic genetic variation may be a factor in the D. melanogaster response to RJ, and should be considered when attempting to elucidate response mechanisms to environmental changes in non-honeybee species. PMID:27486863

  2. Modest increased sensitivity to radiation oncogenesis in ATM heterozygous versus wild-type mammalian cells

    NASA Technical Reports Server (NTRS)

    Smilenov, L. B.; Brenner, D. J.; Hall, E. J.

    2001-01-01

    Subpopulations that are genetically predisposed to radiation-induced cancer could have significant public health consequences. Individuals homozygous for null mutations at the ataxia telangiectasia gene are indeed highly radiosensitive, but their numbers are very small. Ataxia Telangiectasia heterozygotes (1-2% of the population) have been associated with somewhat increased radiosensitivity for some end points, but none directly related to carcinogenesis. Here, intralitter comparisons between wild-type mouse embryo fibroblasts and mouse embryo fibroblasts carrying ataxia telangiectasia mutated (ATM) null mutation indicate that the heterozygous cells are more sensitive to radiation oncogenesis than their normal, litter-matched, counterparts. From these data we suggest that Ataxia Telangiectasia heterozygotes could indeed represent a societally-significant radiosensitive human subpopulation.

  3. Predicting Gene Function from Uncontrolled Expression Variation among Individual Wild-Type Arabidopsis Plants[W

    PubMed Central

    Bhosale, Rahul; Jewell, Jeremy B.; Hollunder, Jens; Koo, Abraham J.K.; Vuylsteke, Marnik; Michoel, Tom; Hilson, Pierre; Goossens, Alain; Howe, Gregg A.; Browse, John; Maere, Steven

    2013-01-01

    Gene expression profiling studies are usually performed on pooled samples grown under tightly controlled experimental conditions to suppress variability among individuals and increase experimental reproducibility. In addition, to mask unwanted residual effects, the samples are often subjected to relatively harsh treatments that are unrealistic in a natural context. Here, we show that expression variations among individual wild-type Arabidopsis thaliana plants grown under the same macroscopic growth conditions contain as much information on the underlying gene network structure as expression profiles of pooled plant samples under controlled experimental perturbations. We advocate the use of subtle uncontrolled variations in gene expression between individuals to uncover functional links between genes and unravel regulatory influences. As a case study, we use this approach to identify ILL6 as a new regulatory component of the jasmonate response pathway. PMID:23943861

  4. Comparative mutational analysis of wild-type and stretched tRNA3(Leu) gene promoters.

    PubMed Central

    Fabrizio, P; Coppo, A; Fruscoloni, P; Benedetti, P; Di Segni, G; Tocchini-Valentini, G P

    1987-01-01

    We demonstrate that, when the yeast tRNA(3Leu) gene is stretched so that the distance between the two portions of the intragenic promoter is increased to 365 base pairs, the A and B blocks remain functional. Mutations in the A block, which show a weak phenotype when inserted in the wild type, exert a dramatic effect when inserted into the stretched gene. Experiments with extensively purified transcription factor tau indicate that the tau B-B block interaction is not influenced by A-B distance; only the ability of tau A to interact with A block sequences is affected, possibly because of the additional free-energy cost of forming a large loop of the intervening DNA. Images PMID:3321052

  5. Proteomic characterization of a wild-type wine strain of Saccharomyces cerevisiae.

    PubMed

    Trabalzini, Lorenza; Paffetti, Alessandro; Ferro, Elisa; Scaloni, Andrea; Talamo, Fabio; Millucci, Lia; Martelli, Paola; Santucci, Annalisa

    2003-12-01

    Saccharomyces cerevisiae is the optimal eukaryotic model system to study mammalian biological responses. At the same time Saccharomyces cerevisiae is also widely utilized as a biotechnological tool in the food industry. Enological Saccharomyces cerevisiae strains have been so far routinely analyzed for their microbiological aspects. Nevertheless, wine yeasts are gaining an increasing interest in the last years since they strongly affect both the vinification process and the organoleptic properties of the final product wine. The protein repertoire is responsible of such features and, consequently, 2D-PAGE can be an useful tool to evaluate and select optimal wine yeast strains. We present here the first proteomic map of a wild-type wine Saccharomyces cerevisiae strain selected for the guided fermentation of very high quality wines. PMID:15141481

  6. Quality assessment of the blue mussel (Mytilus edulis): comparison between commercial and wild types.

    PubMed

    De Witte, B; Devriese, L; Bekaert, K; Hoffman, S; Vandermeersch, G; Cooreman, K; Robbens, J

    2014-08-15

    This study compared species identity, microplastics, chemical and microbial contamination between consumption mussels and wild type mussels, collected at Belgian department stores and Belgian groynes and quaysides, respectively. Species identification based on genetic analysis showed a high number of Mytilus (M.) edulis compared to M. galloprovincialis and M. edulis/galloprovincialis hybrid mussels. The number of total microplastics varied from 2.6 to 5.1 fibres/10 g of mussel. A higher prevalence of orange fibres at quaysides is related to fisheries activities. Chemical contamination of polycyclic aromatic hydrocarbons and polychlorobiphenyls could be related to industrial activities and water turbidity, with maximum concentrations at the quayside of port Zeebrugge. The inverse was noted for Escherichia coli contamination, which was relatively low at Zeebrugge quayside with a total count of 3.9 × 10(2)CFU/100 g tissue, due to limited agricultural effluents. Results of this complementary analysis stress the importance of integrated monitoring and quality assessment. PMID:24969855

  7. Comparative genomics of wild type yeast strains unveils important genome diversity

    PubMed Central

    Carreto, Laura; Eiriz, Maria F; Gomes, Ana C; Pereira, Patrícia M; Schuller, Dorit; Santos, Manuel AS

    2008-01-01

    Background Genome variability generates phenotypic heterogeneity and is of relevance for adaptation to environmental change, but the extent of such variability in natural populations is still poorly understood. For example, selected Saccharomyces cerevisiae strains are variable at the ploidy level, have gene amplifications, changes in chromosome copy number, and gross chromosomal rearrangements. This suggests that genome plasticity provides important genetic diversity upon which natural selection mechanisms can operate. Results In this study, we have used wild-type S. cerevisiae (yeast) strains to investigate genome variation in natural and artificial environments. We have used comparative genome hybridization on array (aCGH) to characterize the genome variability of 16 yeast strains, of laboratory and commercial origin, isolated from vineyards and wine cellars, and from opportunistic human infections. Interestingly, sub-telomeric instability was associated with the clinical phenotype, while Ty element insertion regions determined genomic differences of natural wine fermentation strains. Copy number depletion of ASP3 and YRF1 genes was found in all wild-type strains. Other gene families involved in transmembrane transport, sugar and alcohol metabolism or drug resistance had copy number changes, which also distinguished wine from clinical isolates. Conclusion We have isolated and genotyped more than 1000 yeast strains from natural environments and carried out an aCGH analysis of 16 strains representative of distinct genotype clusters. Important genomic variability was identified between these strains, in particular in sub-telomeric regions and in Ty-element insertion sites, suggesting that this type of genome variability is the main source of genetic diversity in natural populations of yeast. The data highlights the usefulness of yeast as a model system to unravel intraspecific natural genome diversity and to elucidate how natural selection shapes the yeast genome

  8. Characterization of yakju brewed from glutinous rice and wild-type yeast strains isolated from nuruks.

    PubMed

    Kim, Hye Ryun; Kim, Jae-Ho; Bae, Dong-Hoon; Ahn, Byung-Hak

    2010-12-01

    Korean traditional rice wines yakju and takju are generally brewed with nuruk as the source of the saccharogenic enzymes by natural fermentation. To improve the quality of Korean rice wine, the microorganisms in the nuruk need to be studied. The objective of this research was to improve the quality of Korean wine with the wild-type yeast strains isolated from the fermentation starter, nuruk. Only strain YA-6 showed high activity in 20% ethanol. Precipitation of Y89-5-3 was similar to that of very flocculent yeast (〉80%) at 75.95%. Using 18S rRNA sequencing, all 10 strains were identified as Saccharomyces cerevisiae. Volatile compounds present in yakju were analyzed by gas chromatography-mass selective detector. The principal component analysis (PCA) of the volatile compounds grouped long-chain esters on the right side of the first principal component, PC1; these compounds were found in yakju that was made with strains YA-6, Y89-5-3, Y89-5- 2, Y90-9, and Y89-1-1. On the other side of PC1 were short-chain esters; these compounds were found in wines that were brewed with strains Y183-2, Y268-3, Y54-3, Y98-4, and Y88-4. Overall, the results indicated that using different wild-type yeast strains in the fermentation process significantly affects the chemical characteristics of the glutinous rice wine. PMID:21193827

  9. Real-time quantification of wild-type contaminants in glyphosate tolerant soybean

    PubMed Central

    Battistini, Elena; Noli, Enrico

    2009-01-01

    Background Trait purity is a key factor for the successful utilization of biotech varieties and is currently assessed by analysis of individual seeds or plants. Here we propose a novel PCR-based approach to test trait purity that can be applied to bulk samples. To this aim the insertion site of a transgene is characterized and the corresponding sequence of the wild-type (wt) allele is used as diagnostic target for amplification. As a demonstration, we developed a real-time quantitative PCR method to test purity of glyphosate tolerant (Roundup Ready®, RR) soybean. Results The soybean wt sequence at the RR locus was characterized and found to be highly conserved among conventional genotypes, thus allowing the detection of possibly any soybean non-trait contaminant. On the other hand, no amplification product was obtained from RR soybean varieties, indicating that the wt sequence is single copy and represents a suitable marker of conventional soybean presence. In addition, results obtained from the analysis of wt-spiked RR samples demonstrate that it is possible to use the real-time PCR assay to quantify the non-trait contamination with an acceptable degree of accuracy. Conclusion In principle this approach could be successfully applied to any transgenic event, provided that the wild-type sequence is conserved and single copy. The main advantages of the assay here described derive from its applicability to bulk samples, which would allow to increase the number of single seeds or plants forming the analytical sample, thus improving accuracy and throughput while containing costs. For these reasons this application of quantitative PCR could represent a useful tool in agricultural biotechnology. PMID:19267904

  10. Phenylbutyrate Sensitizes Human Glioblastoma Cells Lacking Wild-Type P53 Function to Ionizing Radiation

    SciTech Connect

    Lopez, Carlos A. Feng, Felix Y.; Herman, Joseph M.; Nyati, Mukesh K.; Lawrence, Theodore S.; Ljungman, Mats

    2007-09-01

    Purpose: Histone deacetylase (HDAC) inhibitors induce growth arrest, differentiation, and apoptosis in cancer cells. Phenylbutyrate (PB) is a HDAC inhibitor used clinically for treatment of urea cycle disorders. Because of its low cytotoxicity, cerebrospinal fluid penetration, and high oral bioavailability, we investigated PB as a potential radiation sensitizer in human glioblastoma cell lines. Methods and Materials: Four glioblastoma cell lines were selected for this study. Phenylbutyrate was used at a concentration of 2 mM, which is achievable in humans. Western blots were used to assess levels of acetylated histone H3 in tumor cells after treatment with PB. Flow cytometry was used for cell cycle analysis. Clonogenic assays were performed to assess the effect of PB on radiation sensitivity. We used shRNA against p53 to study the role of p53 in radiosensitization. Results: Treatment with PB alone resulted in hyperacetylation of histones, confirmed by Western blot analysis. The PB alone resulted in cytostatic effects in three cell lines. There was no evidence of G{sub 1} arrest, increase in sub-G{sub 1} fraction or p21 protein induction. Clonogenic assays showed radiosensitization in two lines harboring p53 mutations, with enhancement ratios ({+-} SE) of 1.5 ({+-} 0.2) and 1.3 ({+-} 0.1), respectively. There was no radiopotentiating effect in two cell lines with wild-type p53, but knockdown of wild-type p53 resulted in radiosensitization by PB. Conclusions: Phenylbutyrate can produce p21-independent cytostasis, and enhances radiation sensitivity in p53 mutant human glioblastoma cells in vitro. This suggests the potential application of combined PB and radiotherapy in glioblastoma harboring mutant p53.

  11. LOC283731 promoter hypermethylation prognosticates survival after radiochemotherapy in IDH1 wild-type glioblastoma patients.

    PubMed

    Mock, Andreas; Geisenberger, Christoph; Orlik, Christian; Warta, Rolf; Schwager, Christian; Jungk, Christine; Dutruel, Céline; Geiselhart, Lea; Weichenhan, Dieter; Zucknick, Manuela; Nied, Ann-Katrin; Friauf, Sara; Exner, Janina; Capper, David; Hartmann, Christian; Lahrmann, Bernd; Grabe, Niels; Debus, Jürgen; von Deimling, Andreas; Popanda, Odilia; Plass, Christoph; Unterberg, Andreas; Abdollahi, Amir; Schmezer, Peter; Herold-Mende, Christel

    2016-07-15

    MGMT promoter methylation status is currently the only established molecular prognosticator in IDH wild-type glioblastoma multiforme (GBM). Therefore, we aimed to discover novel therapy-associated epigenetic biomarkers. After enrichment for hypermethylated fractions using methyl-CpG-immunoprecipitation (MCIp), we performed global DNA methylation profiling for 14 long-term (LTS; >36 months) and 15 short-term (STS; 6-10 months) surviving GBM patients. Even after exclusion of the G-CIMP phenotype, we observed marked differences between the LTS and STS methylome. A total of 1,247 probes in 706 genes were hypermethylated in LTS and 463 probes in 305 genes were found to be hypermethylated in STS patients (p values < 0.05, log2 fold change ± 0.5). We identified 13 differentially methylated regions (DMRs) with a minimum of four differentially methylated probes per gene. Indeed, we were able to validate a subset of these DMRs through a second, independent method (MassARRAY) in our LTS/STS training set (ADCY1, GPC3, LOC283731/ISLR2). These DMRs were further assessed for their prognostic capability in an independent validation cohort (n = 62) of non-G-CIMP GBMs from the TCGA. Hypermethylation of multiple CpGs mapping to the promoter region of LOC283731 correlated with improved patient outcome (p = 0.03). The prognostic performance of LOC283731 promoter hypermethylation was confirmed in a third independent study cohort (n = 89), and was independent of gender, performance (KPS) and MGMT status (p = 0.0485, HR = 0.63). Intriguingly, the prediction was most pronounced in younger GBM patients (<60 years). In conclusion, we provide compelling evidence that promoter methylation status of this novel gene is a prognostic biomarker in IDH1 wild-type/non-G-CIMP GBMs. PMID:26934681

  12. Molecular Dynamics Approach in the Comparison of Wild-Type and Mutant Paraoxonase-1 Apoenzyme Form

    PubMed Central

    Amine, Khadija; Miri, Lamia; Naimi, Adil; Saile, Rachid; El Kharrim, Abderrahmane; Mikou, Afaf; Kettani, Anass

    2015-01-01

    There is some evidence linking the mammalian paraoxonase-1 (PON1) loops (L1 and L2) to an increased flexibility and reactivity of its active site with potential substrates. The aim of this work is to study the structural, dynamical, and functional effects of the most flexible regions close to the active site and to determine the impact of mutations on the protein. For both models, wild-type (PON1wild) and PON1 mutant (PON1mut) models, the L1 loop and Q/R and L/M mutations were constructed using MODELLER software. Molecular dynamics simulations of 20 ns at 300 K on fully modeled PON1wild and PON1mut apoenzyme have been done. Detailed analyses of the root-mean-square deviation and fluctuations, H-bonding pattern, and torsion angles have been performed. The PON1wild results were then compared with those obtained for the PON1mut. Our results show that the active site in the wild-type structure is characterized by two distinct movements of opened and closed conformations of the L1 and L2 loops. The alternating and repetitive movement of loops at specific times is consistent with the presence of 11 defined hydrogen bonds. In the PON1mut, these open-closed movements are therefore totally influenced and repressed by the Q/R and L/M mutations. In fact, these mutations seem to impact the PON1mut active site by directly reducing the catalytic core flexibility, while maintaining a significant mobility of the switch regions delineated by the loops surrounding the active site. The impact of the studied mutations on structure and dynamics proprieties of the protein may subsequently contribute to the loss of both flexibility and activity of the PON1 enzyme. PMID:26417201

  13. Efficient Reassignment of a Frequent Serine Codon in Wild-Type Escherichia coli.

    PubMed

    Ho, Joanne M; Reynolds, Noah M; Rivera, Keith; Connolly, Morgan; Guo, Li-Tao; Ling, Jiqiang; Pappin, Darryl J; Church, George M; Söll, Dieter

    2016-02-19

    Expansion of the genetic code through engineering the translation machinery has greatly increased the chemical repertoire of the proteome. This has been accomplished mainly by read-through of UAG or UGA stop codons by the noncanonical aminoacyl-tRNA of choice. While stop codon read-through involves competition with the translation release factors, sense codon reassignment entails competition with a large pool of endogenous tRNAs. We used an engineered pyrrolysyl-tRNA synthetase to incorporate 3-iodo-l-phenylalanine (3-I-Phe) at a number of different serine and leucine codons in wild-type Escherichia coli. Quantitative LC-MS/MS measurements of amino acid incorporation yields carried out in a selected reaction monitoring experiment revealed that the 3-I-Phe abundance at the Ser208AGU codon in superfolder GFP was 65 ± 17%. This method also allowed quantification of other amino acids (serine, 33 ± 17%; phenylalanine, 1 ± 1%; threonine, 1 ± 1%) that compete with 3-I-Phe at both the aminoacylation and decoding steps of translation for incorporation at the same codon position. Reassignments of different serine (AGU, AGC, UCG) and leucine (CUG) codons with the matching tRNA(Pyl) anticodon variants were met with varying success, and our findings provide a guideline for the choice of sense codons to be reassigned. Our results indicate that the 3-iodo-l-phenylalanyl-tRNA synthetase (IFRS)/tRNA(Pyl) pair can efficiently outcompete the cellular machinery to reassign select sense codons in wild-type E. coli. PMID:26544153

  14. Molecular Dynamics Approach in the Comparison of Wild-Type and Mutant Paraoxonase-1 Apoenzyme Form.

    PubMed

    Amine, Khadija; Miri, Lamia; Naimi, Adil; Saile, Rachid; El Kharrim, Abderrahmane; Mikou, Afaf; Kettani, Anass

    2015-01-01

    There is some evidence linking the mammalian paraoxonase-1 (PON1) loops (L1 and L2) to an increased flexibility and reactivity of its active site with potential substrates. The aim of this work is to study the structural, dynamical, and functional effects of the most flexible regions close to the active site and to determine the impact of mutations on the protein. For both models, wild-type (PON1wild) and PON1 mutant (PON1mut) models, the L1 loop and Q/R and L/M mutations were constructed using MODELLER software. Molecular dynamics simulations of 20 ns at 300 K on fully modeled PON1wild and PON1mut apoenzyme have been done. Detailed analyses of the root-mean-square deviation and fluctuations, H-bonding pattern, and torsion angles have been performed. The PON1wild results were then compared with those obtained for the PON1mut. Our results show that the active site in the wild-type structure is characterized by two distinct movements of opened and closed conformations of the L1 and L2 loops. The alternating and repetitive movement of loops at specific times is consistent with the presence of 11 defined hydrogen bonds. In the PON1mut, these open-closed movements are therefore totally influenced and repressed by the Q/R and L/M mutations. In fact, these mutations seem to impact the PON1mut active site by directly reducing the catalytic core flexibility, while maintaining a significant mobility of the switch regions delineated by the loops surrounding the active site. The impact of the studied mutations on structure and dynamics proprieties of the protein may subsequently contribute to the loss of both flexibility and activity of the PON1 enzyme. PMID:26417201

  15. Impact of mTORC1 inhibition on keratinocyte proliferation during skin tumor promotion in wild-type and BK5.AktWT mice.

    PubMed

    Rho, Okkyung; Kiguchi, Kaoru; Jiang, Guiyu; DiGiovanni, John

    2014-11-01

    In this study, we examined the impact of rapamycin on mTORC1 signaling during 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced keratinocyte proliferation and skin tumor promotion in both wild-type (FVB/N) and BK5.Akt(WT) mice. TPA activated mTORC1 signaling in a time-dependent manner in cultured primary mouse keratinocytes and a mouse keratinocyte cell line. Early activation (15-30 min) of mTORC1 signaling induced by TPA was mediated in part by PKC activation, whereas later activation (2-4 h) was mediated by activation of EGFR and Akt. BK5.Akt(WT) transgenic mice, where Akt1 is overexpressed in basal epidermis, are highly sensitive to TPA-induced epidermal proliferation and two-stage skin carcinogenesis. Targeting mTORC1 with rapamycin effectively inhibited TPA-induced epidermal hyperplasia and hyperproliferation as well as tumor promotion in a dose-dependent manner in both wild-type and BK5.Akt(WT) mice. A significant expansion (∼threefold) of the label retaining cell (LRC) population per hair follicle was observed in BK5.Akt(WT) mice compared to FVB/N mice. There was also a significant increase in K15 expressing cells in the hair follicle of transgenic mice that coincided with expression of phospho-Akt, phospho-S6K, and phospho-PRAS40, suggesting an important role of mTORC1 signaling in bulge-region keratinocyte stem cell (KSC) homeostasis. After 2 weeks of TPA treatment, LRCs had moved upward into the interfollicular epidermis from the bulge region of both wild-type and BK5.Akt(WT) mice. TPA-mediated LRC proliferation and migration was significantly inhibited by rapamycin. Collectively, the current data indicate that signaling through mTORC1 contributes significantly to the process of skin tumor promotion through effects on proliferation of the target cells for tumor development. PMID:24114993

  16. Wild-type human TDP-43 expression causes TDP-43 phosphorylation, mitochondrial aggregation, motor deficits and early mortality in transgenic mice

    PubMed Central

    Xu, Ya-Fei; Gendron, Tania F.; Zhang, Yong-Jie; Lin, Wen-Lang; D’Alton, Simon; Sheng, Hong; Casey, Monica Castanedes; Tong, Jimei; Knight, Joshua; Yu, Xin; Rademakers, Rosa; Boylan, Kevin; Hutton, Mike; McGowan, Eileen; Dickson, Dennis W.; Lewis, Jada; Petrucelli, Leonard

    2011-01-01

    Transactivation response DNA-binding protein 43 (TDP-43) is a principal component of ubiquitinated inclusions in frontotemporal lobar degeneration with ubiquitin-positive inclusions and in amyotrophic lateral sclerosis (ALS). Mutations in TARDBP, the gene encoding TDP-43, are associated with sporadic and familial ALS, yet multiple neurodegenerative diseases exhibit TDP-43 pathology without known TARDBP mutations. While TDP-43 has been ascribed a number of roles in normal biology, including mRNA splicing and transcription regulation, elucidating disease mechanisms associated with this protein is hindered by the lack of models to dissect such functions. We have generated transgenic (TDP-43PrP) mice expressing full-length human TDP-43 (hTDP-43) driven by the mouse prion promoter to provide a tool to analyze the role of wild-type hTDP-43 in the brain and spinal cord. Expression of hTDP-43 caused a dose dependant down regulation of mouse TDP-43 RNA and protein. Moderate overexpression of hTDP-43 resulted in TDP-43 truncation, increased cytoplasmic and nuclear ubiquitin levels, as well as intranuclear and cytoplasmic aggregates that were immunopositive for phosphorylated TDP-43. Of note, abnormal juxtanuclear aggregates of mitochondria were observed, accompanied by enhanced levels of Fis1 and phosphorylated DLP1, key components of the mitochondrial fission machinery. Conversely, a marked reduction in mitofusin 1 expression, which plays an essential role in mitochondrial fusion, was observed in TDP-43PrP mice. Finally, TDP-43PrP mice showed reactive gliosis, axonal and myelin degeneration, gait abnormalities and early lethality. This TDP-43 transgenic line provides a valuable tool for identifying potential roles of wild-type TDP-43 within the central nervous system and for studying TDP-43-associated neurotoxicity. PMID:20702714

  17. Oxidative stress mediates impairment of muscle function in transgenic mice with elevated level of wild-type Cu/Zn superoxide dismutase

    PubMed Central

    Peled-Kamar, M.; Lotem, J.; Wirguin, I.; Weiner, L.; Hermalin, A.; Groner, Y.

    1997-01-01

    Cases of familial amyotrophic lateral sclerosis (fALS; a neurodegenerative disorder) have been reported in which the gene for Cu/Zn superoxide dismutase (CuZnSOD) was mutated. Several studies with the fALS mutant CuZnSOD in transgenic mice and cells showed that the fALS mutations act through an as yet undefined dominant gain-of-function mechanism. Wild-type CuZnSOD catalyzes the dismutation of superoxide (O2⨪) but also produces hydroxyl radicals (•OH) with H2O2 as substrate. Two laboratories have recently demonstrated that the •OH production ability was preferentially enhanced by the fALS mutant CuZnSOD, suggesting that this might be the function gained in fALS. In this study, we used transgenic CuZnSOD (Tg-CuZnSOD) mice with elevated levels of CuZnSOD to determine whether overexpression of wild-type CuZnSOD was also associated with increased •OH production and impaired muscle function. Enhanced formation of •OH was detected, by spin trapping, in brain and muscle extracts of the Tg-CuZnSOD mice. Three independently derived Tg-CuZnSOD lines showed muscle abnormalities, reflected by altered electromyography (EMG) and diminished performance in the rope grip test. After treatment with paraquat (PQ), a widely used herbicide and O2⨪-generating compound, muscle disability significantly deteriorated in Tg-CuZnSOD mice but not in control mice. The results indicate that elevated levels of CuZnSOD cause indigenous long-term oxidative stress leading to impairment of muscle function. These findings may provide valuable clues about the concurred role of indigenous oxidative stress and exogenous agents in the etiology of sporadic ALS and several other neurodegenerative diseases in which a specific subset of neurons is affected. PMID:9108073

  18. Gene expression of the IGF pathway family distinguishes subsets of gastrointestinal stromal tumors wild type for KIT and PDGFRA.

    PubMed

    Beadling, Carol; Patterson, Janice; Justusson, Emily; Nelson, Dylan; Pantaleo, Maria A; Hornick, Jason L; Chacón, Matias; Corless, Christopher L; Heinrich, Michael C

    2013-02-01

    Gastrointestinal stromal tumors (GISTs) arise from the interstitial cells of Cajal (ICCs) and are the most common mesenchymal neoplasm of the gastrointestinal tract. While the majority of GISTs harbor activating mutations in either the v-kit Hardy-Zuckerman feline sarcoma viral oncogene homolog (KIT) or platelet-derived growth factor receptor alpha (PDGFRA) tyrosine kinases, approximately 10-15% of adult GISTs and 85% of pediatric GISTs lack such mutations. These "wild-type" GISTs have been reported to express high levels of the insulin-like growth factor 1 receptor (IGF1R), and IGF1R-targeted therapy of wild-type GISTs is being evaluated in clinical trials. However, it is not clear that all wild-type GISTs express IGF1R, because studies to date have predominantly focused on a particular subtype of gastric wild-type GIST that is deficient in the mitochondrial succinate dehydrogenase (SDH) complex. This study of a series of 136 GISTs, including 72 wild-type specimens, was therefore undertaken to further characterize wild-type GIST subtypes based on the relative expression of transcripts encoding IGF1R. Additional transcripts relevant to GIST biology were also evaluated, including members of the IGF-signaling pathway (IGF1, IGF2, and insulin receptor [INSR]), neural markers (CDH2[CDH: Cadherin], neurofilament, light polypeptide, LHX2 [LHX: LIM homeobox], and KIRREL3 [KIRREL: kin of IRRE like]), KIT, PDGFRA, CD34, and HIF1A. Succinate dehydrogenase complex, subunit B protein expression was also assessed as a measure of SDH complex integrity. In addition to the previously described SDH-deficient, IGF1R(high) wild-type GISTs, other SDH-intact wild-type subpopulations were defined by high relative expression of IGF1R, neural markers, IGF1 and INSR, or low IGF1R coupled with high IGF2. These results underscore the complexity and heterogeneity of wild-type GISTs that will need to be factored into molecularly-targeted therapeutic strategies. PMID:24133624

  19. Poor competitive fitness of transgenically mitigated tobacco in competition with the wild type in a replacement series.

    PubMed

    Al-Ahmad, Hani; Galili, Shmuel; Gressel, Jonathan

    2005-10-01

    Transgenic crops can interbreed with other crop cultivars or with related weeds, increasing the potential of the hybrid progeny for competition. To prevent generating competitive hybrids, we previously tested tobacco (Nicotiana tabacum L.) as a model for validating the transgenic mitigation (TM) concept using tandem constructs where a gene of choice is linked to mitigating genes that are positive or neutral to the crop, but deleterious to a recipient under competition. Here, we examine the efficacy of the TM concept at various ratios of transgenically mitigated tobacco in competition with the wild type tobacco in an ecological replacement series. The dwarf/herbicide-resistant TM transgenic plants cultivated alone under self-competition grew well and formed many more flowers than the tall wild type, which is an indication of greater reproductivity. In contrast to the wild type, TM flowering was almost completely suppressed in mixed cultures at most TM/wild type ratios up to 75% transgenic, as the TM plants were extremely unfit to reproduce. In addition, homozygous TM progeny had an even lower competitive fitness against the wild type than hemizygous/homozygous TM segregants. Thus, the TM technology was effective in reducing the risk of transgene establishment of intraspecific transgenic hybrids at different competitive levels, at the close spacing typical of weed populations. PMID:15931502

  20. Mitochondrial Function in Cell Wall Glycoprotein Synthesis in Saccharomyces cerevisiae NCYC 625 (Wild Type) and [rho0] Mutants

    PubMed Central

    Iung, Annie Rakotoarivony; Coulon, Joël; Kiss, Ferenc; Ekome, Jacques Ngondi; Vallner, Judit; Bonaly, Roger

    1999-01-01

    We studied phosphopeptidomannans (PPMs) of two Saccharomyces cerevisiae NCYC 625 strains (S. diastaticus): a wild type strain grown aerobically, anaerobically, and in the presence of antimycin and a [rho0] mutant grown aerobically and anaerobically. The aerobic wild-type cultures were highly flocculent, but all others were weakly flocculent. Ligands implicated in flocculation of mutants or antimycin-treated cells were not aggregated as much by concanavalin A as were those of the wild type. The [rho0] mutants and antimycin-treated cells differ from the wild type in PPM composition and invertase, acid phosphatase, and glucoamylase activities. PPMs extracted from different cells differ in the protein but not in the glycosidic moiety. The PPMs were less stable in mitochondrion-deficient cells than in wild-type cells grown aerobically, and this difference may be attributable to defective mitochondrial function during cell wall synthesis. The reduced flocculation of cells grown in the presence of antimycin, under anaerobiosis, or carrying a [rho0] mutation may be the consequence of alterations of PPM structures which are the ligands of lectins, both involved in this cell-cell recognition phenomenon. These respiratory chain alterations also affect peripheral, biologically active glycoproteins such as extracellular enzymes and peripheral PPMs. PMID:10583995

  1. Acquired transmissibility of sheep-passaged L-type bovine spongiform encephalopathy prion to wild-type mice.

    PubMed

    Okada, Hiroyuki; Masujin, Kentaro; Miyazawa, Kohtaro; Yokoyama, Takashi

    2015-01-01

    L-type bovine spongiform encephalopathy (L-BSE) is an atypical form of BSE that is transmissible to cattle and several lines of prion protein (PrP) transgenic mice, but not to wild-type mice. In this study, we examined the transmissibility of sheep-passaged L-BSE prions to wild-type mice. Disease-associated prion protein (PrP(Sc)) was detected in the brain and/or lymphoid tissues during the lifespan of mice that were asymptomatic subclinical carriers, indicating that wild-type mice were susceptible to sheep-passaged L-BSE. The morphological characteristics of the PrP(Sc) of sheep-passaged L-BSE included florid plaques that were distributed mainly in the cerebral cortex and hippocampus of subsequent passaged mice. The PrP(Sc) glycoform profiles of wild-type mice infected with sheep-passaged L-BSE were similar to those of the original isolate. The data indicate that sheep-passaged L-BSE has an altered host range and acquired transmissibility to wild-type mice. PMID:26169916

  2. Viral adaptation to an antiviral protein enhances the fitness level to above that of the uninhibited wild type.

    PubMed

    Cherwa, James E; Sanchez-Soria, Pablo; Wichman, Holly A; Fane, Bentley A

    2009-11-01

    Viruses often evolve resistance to antiviral agents. While resistant strains are able to replicate in the presence of the agent, they generally exhibit lower fitness than the wild-type strain in the absence of the inhibitor. In some cases, resistant strains become dependent on the antiviral agent. However, the agent rarely, if ever, elevates dependent strain fitness above the uninhibited wild-type level. This would require an adaptive mechanism to convert the antiviral agent into a beneficial growth factor. Using an inhibitory scaffolding protein that specifically blocks phiX174 capsid assembly, we demonstrate that such mechanisms are possible. To obtain the quintuple-mutant resistant strain, the wild-type virus was propagated for approximately 150 viral life cycles in the presence of increasing concentrations of the inhibitory protein. The expression of the inhibitory protein elevated the strain's fitness significantly above the uninhibited wild-type level. Thus, selecting for resistance coselected for dependency, which was characterized and found to operate on the level of capsid nucleation. To the best of our knowledge, this is the first report of a virus evolving a mechanism to productively utilize an antiviral agent to stimulate its fitness above the uninhibited wild-type level. The results of this study may be predictive of the types of resistant phenotypes that could be selected by antiviral agents that specifically target capsid assembly. PMID:19726521

  3. Overexpression of poplar cellulase accelerates growth and disturbs the closing movements of leaves in sengon.

    PubMed

    Hartati, Sri; Sudarmonowati, Enny; Park, Yong Woo; Kaku, Tomomi; Kaida, Rumi; Baba, Kei'ichi; Hayashi, Takahisa

    2008-06-01

    In this study, poplar (Populus alba) cellulase (PaPopCel1) was overexpressed in a tropical Leguminosae tree, sengon (Paraserianthes falcataria), by the Agrobacterium tumefaciens method. PaPopCel1 overexpression increased the length and width of stems with larger leaves, which showed a moderately higher density of green color than leaves of the wild type. The pairs of leaves on the transgenic plants closed more slowly during sunset than those on the wild-type plants. When main veins from each genotype were excised and placed on a paper towel, however, the leaves of the transgenic plants closed more rapidly than those of the wild-type plant. Based on carbohydrate analyses of cell walls, the leaves of the transgenic plants contained less wall-bound xyloglucan than those of the wild-type plants. In situ xyloglucan endotransglucosylase activity showed that the incorporation of whole xyloglucan, potentially for wall tightening, occurred in the parenchyma cells (motor cells) of the petiolule pulvinus attached to the main vein, although the transgenic plant incorporated less whole xyloglucan than the wild-type plant. These observations support the hypothesis that the paracrystalline sites of cellulose microfibrils are attacked by poplar cellulase, which loosens xyloglucan intercalation, resulting in an irreversible wall modification. This process could be the reason why the overexpression of poplar cellulase both promotes plant growth and disturbs the biological clock of the plant by altering the closing movements of the leaves of the plant. PMID:18417637

  4. Clinical and metabolic parameters in non-small cell lung carcinoma and colorectal cancer patients with and without KRAS mutations.

    PubMed

    Yilmaz, Ahmet; Mohamed, Nehad; Patterson, Kara A; Tang, Yan; Shilo, Konstantin; Villalona-Calero, Miguel A; Davis, Michael E; Zhou, Xiao-Ping; Frankel, Wendy; Otterson, Gregory A; Zhao, Weiqiang

    2014-09-01

    Lung cancer (LC) and colorectal cancer (CRC) are the first and second deadliest types of cancer worldwide. EGFR-based therapy has been used in the treatment of these cancers with variable success. Presence of mutations in the KRAS driver oncogene, possibly induced by environmental factors such as carcinogens in diet and cigarette smoke, may confer worse prognosis and resistance to treatment for reasons not fully understood. Data on possible associations between KRAS mutational status and clinical and metabolic parameters, which may help in clinical management, as well as in identifying risk factors for developing these cancers, are limited in the current literature. We sequenced the KRAS gene and investigated the associations of variations in 108 patients with non-small cell lung carcinoma (NSCLC), the most common form of LC, and in 116 patients with CRC. All of the mutations originated from the guanosine nucleotide and over half of all transversions in NSCLC and CRC were c.34 G>T and c.35 G>T, respectively. c.35 G>A was the most frequent type of transition in both cancers. Excluding smoking, the clinical and metabolic parameters in patients carrying mutant and wild type KRAS were similar except that the CRC patients with transversion mutations were 8.6 years younger than those carrying the transitions (P < 0.01). Dyslipidemia, hypertension, family cancer history, and age of diagnosis older than 60 years were more frequent in NSCLC than CRC (P ≤ 0.04). These results suggest that most of the clinical and metabolic parameters investigated in this study are probably not associated with the more aggressive phenotype and differences in response to EGFR-based treatment previously reported in patients with KRAS mutations. However, the increased rates of abnormal metabolic parameters in patients with NSCLC in comparison to CRC indicate that these parameters may be more important in the management of NSCLC. CRC patients carrying transition mutations are older than those

  5. Data for proteomic profiling of Anthers from a photosensitive male sterile mutant and wild-type cotton (Gossypium hirsutum L.).

    PubMed

    Liu, Ji; Pang, Chaoyou; Wei, Hengling; Song, Meizhen; Meng, Yanyan; Ma, Jianhui; Fan, Shuli; Yu, Shuxun

    2015-09-01

    Cotton is an important economic crop, used mainly for the production of textile fiber. Using a space mutation breeding technique, a novel photosensitive genetic male sterile mutant CCRI9106 was isolated from the wild-type upland cotton cultivar CCRI040029. To study the male sterile mechanisms of CCRI9106, histological and iTRAQ-facilitated proteomic analyses of anthers were performed. This data article contains data related to the research article titled iTRAQ-Facilitated Proteomic Profiling of Anthers From a Photosensitive Male Sterile Mutant and Wild-type Cotton (Gossypium hirsutum L.)[1]. This research article describes the iTRAQ-facilitated proteomic analysis of the wild-type and a photosensitive male sterile mutant in cotton. The report indicated that exine formation defect is the key reason for male sterility in mutant plant. The information presented here represents the tables and figures that detail the processing of the raw data obtained from iTRAQ analysis. PMID:26958592

  6. Detection and differentiation of wild-type and a vaccine strain of Streptococcus equi ssp. equi using pyrosequencing.

    PubMed

    Livengood, Julia L; Lanka, Saraswathi; Maddox, Carol; Tewari, Deepanker

    2016-07-25

    Streptococcus equi subspecies equi (S. equi), the causative agent of strangles, is an important equine pathogen. Strangles is a highly contagious disease and a commercial modified live vaccine (MLV) is used for protection, which although effective, may also result in clinical signs of the disease. A rapid means to differentiate between the MLV and wild-type infection is crucial for quarantine release and limiting the disease spread. This study describes the use of a pyrosequencing assay targeting a single nucleotide deletion upstream of the SzPSe gene to distinguish between the wild-type and vaccine strains. A set of 96 characterized clinical specimens and isolates were tested using the assay. The assay was successful in differentiating between wild-type S. equi and the vaccine strains and in discriminating S. equi from other Streptococci. The vaccine strain was identified in 61.7% (29/47) of the strangles cases in horses with a history of MLV vaccination. PMID:27317457

  7. Lunatic Fringe is a potent tumor suppressor in Kras-initiated pancreatic cancer.

    PubMed

    Zhang, S; Chung, W-C; Xu, K

    2016-05-12

    Notch controls pancreatic differentiation during development and is reactivated in pancreatic cancer. In recent years, the importance of Notch signaling in pancreatic tumorigenesis has become increasingly evident; however, it remains unclear how Notch activities are regulated in this context. Here we report differential regulation of Notch receptors by Lunatic Fringe (Lfng), which encodes an O-fucosylpeptide 3-β-N-acetylglucosaminyltransferase known to modify epidermal growth factor repeats in the Notch extracellular domain, during pathogenesis of Kras-induced pancreatic ductal adenocarcinoma (PDAC). We show that Lfng is uniquely expressed in a subset of acinar cells in the adult pancreas. Deletion of Lfng in the Kras(LSL-G12D/+);Pdx1-Cre mouse model caused increased activation of Notch3 throughout PDAC initiation and progression, and Notch1 after the onset of disease, associated with marked upregulation of Notch target gene Hes1. Deletion of Lfng also resulted in accumulation of Aldh1-positive cell population. We found that loss of Lfng significantly accelerated Kras-initiated PDAC development and shortened survival of the PDAC mice. Interestingly, Lfng-deficient tumors showed a propensity for a poorly differentiated state with features of epithelial-to-mesenchymal transition. Likewise, knockdown of LFNG in human PDAC cell lines caused elevated Notch activation, associated with either accelerated cell proliferation or expanded Aldh1-positive cell population. Deletion of Lfng resulted in downregulation of Tgfb1, Tgfb2 and Tgfbr2 expression in the wild-type pancreas at all ages examined, and in the Kras(LSL-G12D/+);Pdx1-Cre pancreas after PDAC onset, as well as reduced phospho-Smad2 levels in pancreatic tumors. We provide evidence that Lfng regulates transforming growth factor (TGF)-β signaling through Notch-mediated transcriptional repression of TGF-β pathway genes. Taken together, our results reveal a potent tumor-suppressive function for Lfng and crosstalk

  8. TraK and TraB are conserved outer membrane proteins of the Neisseria gonorrhoeae Type IV secretion system and are expressed at low levels in wild-type cells.

    PubMed

    Ramsey, Meghan E; Hackett, Kathleen T; Bender, Tobias; Kotha, Chaitra; van der Does, Chris; Dillard, Joseph P

    2014-08-15

    Neisseria gonorrhoeae uses a type IV secretion system (T4SS) to secrete chromosomal DNA into the medium, and this DNA is effective in transforming other gonococci via natural transformation. In addition, the T4SS is important in the initial stages of biofilm development and mediates intracellular iron uptake in the absence of TonB. To better understand the mechanism of type IV secretion in N. gonorrhoeae, we examined the expression levels and localization of two predicted T4SS outer membrane proteins, TraK and TraB, in the wild-type strain as well as in overexpression strains and in a strain lacking all of the T4SS proteins. Despite very low sequence similarity to known homologues, TraB (VirB10 homolog) and TraK (VirB9 homolog) localized similarly to related proteins in other systems. Additionally, we found that TraV (a VirB7 homolog) interacts with TraK, as in other T4SSs. However, unlike in other systems, neither TraK nor TraB required the presence of other T4SS components for proper localization. Unlike other gonococcal T4SS proteins we have investigated, protein levels of the outer membrane proteins TraK and TraB were extremely low in wild-type cells and were undetectable by Western blotting unless overexpressed or tagged with a FLAG3 triple-epitope tag. Localization of TraK-FLAG3 in otherwise wild-type cells using immunogold electron microscopy of thin sections revealed a single gold particle on some cells. These results suggest that the gonococcal T4SS may be present in single copy per cell and that small amounts of T4SS proteins TraK and TraB are sufficient for DNA secretion. PMID:24914183

  9. TraK and TraB Are Conserved Outer Membrane Proteins of the Neisseria gonorrhoeae Type IV Secretion System and Are Expressed at Low Levels in Wild-Type Cells

    PubMed Central

    Ramsey, Meghan E.; Hackett, Kathleen T.; Bender, Tobias; Kotha, Chaitra; van der Does, Chris

    2014-01-01

    Neisseria gonorrhoeae uses a type IV secretion system (T4SS) to secrete chromosomal DNA into the medium, and this DNA is effective in transforming other gonococci via natural transformation. In addition, the T4SS is important in the initial stages of biofilm development and mediates intracellular iron uptake in the absence of TonB. To better understand the mechanism of type IV secretion in N. gonorrhoeae, we examined the expression levels and localization of two predicted T4SS outer membrane proteins, TraK and TraB, in the wild-type strain as well as in overexpression strains and in a strain lacking all of the T4SS proteins. Despite very low sequence similarity to known homologues, TraB (VirB10 homolog) and TraK (VirB9 homolog) localized similarly to related proteins in other systems. Additionally, we found that TraV (a VirB7 homolog) interacts with TraK, as in other T4SSs. However, unlike in other systems, neither TraK nor TraB required the presence of other T4SS components for proper localization. Unlike other gonococcal T4SS proteins we have investigated, protein levels of the outer membrane proteins TraK and TraB were extremely low in wild-type cells and were undetectable by Western blotting unless overexpressed or tagged with a FLAG3 triple-epitope tag. Localization of TraK-FLAG3 in otherwise wild-type cells using immunogold electron microscopy of thin sections revealed a single gold particle on some cells. These results suggest that the gonococcal T4SS may be present in single copy per cell and that small amounts of T4SS proteins TraK and TraB are sufficient for DNA secretion. PMID:24914183

  10. The mechanism of dehydration in chromophore maturation of wild-type green fluorescent protein: A theoretical study

    NASA Astrophysics Data System (ADS)

    Ma, Yingying; Yu, Jian-Guo; Sun, Qiao; Li, Zhen; Smith, Sean C.

    2015-07-01

    An interesting aspect of the green fluorescent protein (GFP) is its autocatalytic chromophore maturation. Numerous experimental studies have indicated that dehydration is the last step in the chromophore maturation process of wild-type GFP. Based on the crystal structure of wild-type GFP, the mechanism of the reverse reaction of dehydration was investigated by using density functional theory (DFT) in this study. Our results proposed that the dehydration is exothermic. Moreover, the rate-limiting step of the mechanism is the proton on guanidinium of Arg96 transferring to the β-carbon anion of Tyr66, which is consistent with the experimental observation.

  11. Gene expression of the IGF pathway family distinguishes subsets of gastrointestinal stromal tumors wild type for KIT and PDGFRA

    PubMed Central

    Beadling, Carol; Patterson, Janice; Justusson, Emily; Nelson, Dylan; Pantaleo, Maria A.; Hornick, Jason L.; Chacón, Matias; Corless, Christopher L.; Heinrich, Michael C.

    2013-01-01

    Gastrointestinal stromal tumors (GISTs) arise from the interstitial cells of Cajal (ICCs) and are the most common mesenchymal neoplasm of the gastrointestinal tract. While the majority of GISTs harbor activating mutations in either the v-kit Hardy-Zuckerman feline sarcoma viral oncogene homolog (KIT) or platelet-derived growth factor receptor alpha (PDGFRA) tyrosine kinases, approximately 10–15% of adult GISTs and 85% of pediatric GISTs lack such mutations. These “wild-type” GISTs have been reported to express high levels of the insulin-like growth factor 1 receptor (IGF1R), and IGF1R-targeted therapy of wild-type GISTs is being evaluated in clinical trials. However, it is not clear that all wild-type GISTs express IGF1R, because studies to date have predominantly focused on a particular subtype of gastric wild-type GIST that is deficient in the mitochondrial succinate dehydrogenase (SDH) complex. This study of a series of 136 GISTs, including 72 wild-type specimens, was therefore undertaken to further characterize wild-type GIST subtypes based on the relative expression of transcripts encoding IGF1R. Additional transcripts relevant to GIST biology were also evaluated, including members of the IGF-signaling pathway (IGF1, IGF2, and insulin receptor [INSR]), neural markers (CDH2[CDH: Cadherin], neurofilament, light polypeptide, LHX2 [LHX: LIM homeobox], and KIRREL3 [KIRREL: kin of IRRE like]), KIT, PDGFRA, CD34, and HIF1A. Succinate dehydrogenase complex, subunit B protein expression was also assessed as a measure of SDH complex integrity. In addition to the previously described SDH-deficient, IGF1Rhigh wild-type GISTs, other SDH-intact wild-type subpopulations were defined by high relative expression of IGF1R, neural markers, IGF1 and INSR, or low IGF1R coupled with high IGF2. These results underscore the complexity and heterogeneity of wild-type GISTs that will need to be factored into molecularly-targeted therapeutic strategies. PMID:24133624

  12. Matrix Metalloproteinase-10 Promotes Kras-Mediated Bronchio-Alveolar Stem Cell Expansion and Lung Cancer Formation

    PubMed Central

    Regala, Roderick P.; Justilien, Verline; Walsh, Michael P.; Weems, Capella; Khoor, Andras; Murray, Nicole R.; Fields, Alan P.

    2011-01-01

    Matrix metalloproteinase 10 (MMP-10; stromelysin 2) is a member of a large family of structurally related matrix metalloproteinases, many of which have been implicated in tumor progression, invasion and metastasis. We recently identified Mmp10 as a gene that is highly induced in tumor-initiating lung bronchioalveolar stem cells (BASCs) upon activation of oncogenic Kras in a mouse model of lung adenocarcinoma. However, the potential role of Mmp10 in lung tumorigenesis has not been addressed. Here, we demonstrate that Mmp10 is overexpressed in lung tumors induced by either the smoke carcinogen urethane or oncogenic Kras. In addition, we report a significant reduction in lung tumor number and size after urethane exposure or genetic activation of oncogenic Kras in Mmp10 null (Mmp10−/−) mice. This inhibitory effect is reflected in a defect in the ability of Mmp10-deficient BASCs to expand and undergo transformation in response to urethane or oncogenic Kras in vivo and in vitro, demonstrating a role for Mmp10 in the tumor-initiating activity of Kras-transformed lung stem cells. To determine the potential relevance of MMP10 in human cancer we analyzed Mmp10 expression in publicly-available gene expression profiles of human cancers. Our analysis reveals that MMP10 is highly overexpressed in human lung tumors. Gene set enhancement analysis (GSEA) demonstrates that elevated MMP10 expression correlates with both cancer stem cell and tumor metastasis genomic signatures in human lung cancer. Finally, Mmp10 is elevated in many human tumor types suggesting a widespread role for Mmp10 in human malignancy. We conclude that Mmp10 plays an important role in lung tumor initiation via maintenance of a highly tumorigenic, cancer-initiating, stem-like cell population, and that Mmp10 expression is associated with stem-like, highly metastatic genotypes in human lung cancers. These results indicate that Mmp10 may represent a novel therapeutic approach to target lung cancer stem cells

  13. Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro

    PubMed Central

    2013-01-01

    Background Familial hyperaldosteronism type I (FH-I) is caused by the unequal recombination between the 11beta-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes, resulting in the generation of a CYP11B1/B2 chimeric gene and abnormal adrenal aldosterone production. Affected patients usually show severe hypertension and an elevated frequency of stroke at a young age. Aldosterone levels rise during pregnancy, yet in pregnant women with FH-1, their hypertensive condition either remains unchanged or may even improve. The purpose of this study was to investigate in vitro whether female sex steroids modulate the activity of chimeric (ASCE) or wild type (ASWT) aldosterone synthase enzymes. Methods We designed an in vitro assay using HEK-293 cell line transiently transfected with vectors containing the full ASCE or ASWT cDNAs. Progesterone or estradiol effects on AS enzyme activities were evaluated in transfected cells incubated with deoxycorticosterone (DOC) alone or DOC plus increasing doses of these steroids. Results In our in vitro model, both enzymes showed similar apparent kinetic parameters (Km = 1.191 microM and Vmax = 27.08 microM/24 h for ASCE and Km = 1.163 microM and Vmax = 36.98 microM/24 h for ASWT; p = ns, Mann–Whitney test). Progesterone inhibited aldosterone production by ASCE- and ASWT-transfected cells, while estradiol demonstrated no effect. Progesterone acted as a competitive inhibitor for both enzymes. Molecular modelling studies and binding affinity estimations indicate that progesterone might bind to the substrate site in both ASCE and ASWT, supporting the idea that this steroid could regulate these enzymatic activities and contribute to the decay of aldosterone synthase activity in chimeric gene-positive patients. Conclusions Our results show an inhibitory action of progesterone in the aldosterone synthesis by chimeric or wild type aldosterone synthase enzymes. This is a novel regulatory mechanism of progesterone

  14. Characterization of Arabidopsis thaliana FLAVONOL SYNTHASE 1 (FLS1) -overexpression plants in response to abiotic stress.

    PubMed

    Nguyen, Nguyen Hoai; Kim, Jun Hyeok; Kwon, Jaeyoung; Jeong, Chan Young; Lee, Wonje; Lee, Dongho; Hong, Suk-Whan; Lee, Hojoung

    2016-06-01

    Flavonoids are an important group of secondary metabolites that are involved in plant growth and contribute to human health. Many studies have focused on the biosynthesis pathway, biochemical characters, and biological functions of flavonoids. In this report, we showed that overexpression of FLS1 (FLS1-OX) not only altered seed coat color (resulting in a light brown color), but also affected flavonoid accumulation. Whereas fls1-3 mutants accumulated higher anthocyanin levels, FLS1-OX seedlings had lower levels than those of the wild-type. Besides, shoot tissues of FLS1-OX plants exhibited lower flavonol levels than those of the wild-type. However, growth performance and abiotic stress tolerance of FLS1-OX, fls1-3, and wild-type plants were not significantly different. Taken together, FLS1 can be manipulated (i.e., silenced or overexpressed) to redirect the flavonoid biosynthetic pathway toward anthocyanin production without negative effects on plant growth and development. PMID:26990404

  15. NVP-BKM120, a novel PI3K inhibitor, shows synergism with a STAT3 inhibitor in human gastric cancer cells harboring KRAS mutations

    PubMed Central

    PARK, EUNJU; PARK, JINAH; HAN, SAE-WON; IM, SEOCK-AH; KIM, TAE-YOU; OH, DO-YOUN; BANG, YUNG-JUE

    2012-01-01

    Aberrations of Phosphoinositide 3-kinase (PI3K)/AKT signaling are frequently observed in many types of cancer, promoting its emergence as a promising target for cancer treatment. PI3K can become activated by various pathways, one of which includes RAS. RAS can not only directly activate the PI3K/AKT pathway via binding to p110 of PI3K, but also regulates mTOR via ERK or RSK independently of the PI3K/AKT pathway. Thus, actively mutated RAS can constitutively activate PI3K signaling. Additionally, in RAS tumorigenic transformation, signal transducer and activator of transcription 3 (STAT3) has been known also to be required. In this study, we examined the efficacy of NVP-BKM120, a pan-class I PI3K inhibitor in human gastric cancer cells and hypothesized that the combined inhibition of PI3K and STAT3 would be synergistic in KRAS mutant gastric cancer cells. NVP-BKM120 demonstrated anti-proliferative activity in 11 human gastric cancer cell lines by decreasing mTOR downstream signaling. But NVP-BKM120 treatment increased p-AKT by subsequent abrogation of feedback inhibition by stabilizing insulin receptor substrate-1. In KRAS mutant gastric cancer cells, either p-ERK or p-STAT3 was also increased upon treatment of NVP-BKM120. The synergistic efficacy study demonstrated that dual PI3K and STAT3 blockade showed a synergism in cells harboring mutated KRAS by inducing apoptosis. The synergistic effect was not seen in KRAS wild-type cells. Together, these findings suggest for the first time that the dual inhibition of PI3K and STAT3 signaling may be an effective therapeutic strategy for KRAS mutant gastric cancer patients. PMID:22159814

  16. 454 next generation-sequencing outperforms allele-specific PCR, Sanger sequencing, and pyrosequencing for routine KRAS mutation analysis of formalin-fixed, paraffin-embedded samples

    PubMed Central

    Altimari, Annalisa; de Biase, Dario; De Maglio, Giovanna; Gruppioni, Elisa; Capizzi, Elisa; Degiovanni, Alessio; D’Errico, Antonia; Pession, Annalisa; Pizzolitto, Stefano; Fiorentino, Michelangelo; Tallini, Giovanni

    2013-01-01

    Detection of KRAS mutations in archival pathology samples is critical for therapeutic appropriateness of anti-EGFR monoclonal antibodies in colorectal cancer. We compared the sensitivity, specificity, and accuracy of Sanger sequencing, ARMS-Scorpion (TheraScreen®) real-time polymerase chain reaction (PCR), pyrosequencing, chip array hybridization, and 454 next-generation sequencing to assess KRAS codon 12 and 13 mutations in 60 nonconsecutive selected cases of colorectal cancer. Twenty of the 60 cases were detected as wild-type KRAS by all methods with 100% specificity. Among the 40 mutated cases, 13 were discrepant with at least one method. The sensitivity was 85%, 90%, 93%, and 92%, and the accuracy was 90%, 93%, 95%, and 95% for Sanger sequencing, TheraScreen real-time PCR, pyrosequencing, and chip array hybridization, respectively. The main limitation of Sanger sequencing was its low analytical sensitivity, whereas TheraScreen real-time PCR, pyrosequencing, and chip array hybridization showed higher sensitivity but suffered from the limitations of predesigned assays. Concordance between the methods was k = 0.79 for Sanger sequencing and k > 0.85 for the other techniques. Tumor cell enrichment correlated significantly with the abundance of KRAS-mutated deoxyribonucleic acid (DNA), evaluated as ΔCt for TheraScreen real-time PCR (P = 0.03), percentage of mutation for pyrosequencing (P = 0.001), ratio for chip array hybridization (P = 0.003), and percentage of mutation for 454 next-generation sequencing (P = 0.004). Also, 454 next-generation sequencing showed the best cross correlation for quantification of mutation abundance compared with all the other methods (P < 0.001). Our comparison showed the superiority of next-generation sequencing over the other techniques in terms of sensitivity and specificity. Next-generation sequencing will replace Sanger sequencing as the reference technique for diagnostic detection of KRAS mutation in archival tumor tissues. PMID

  17. Auto-Assembling Detoxified Staphylococcus aureus Alpha-Hemolysin Mimicking the Wild-Type Cytolytic Toxin

    PubMed Central

    Fiaschi, Luigi; Di Palo, Benedetta; Scarselli, Maria; Pozzi, Clarissa; Tomaszewski, Kelly; Galletti, Bruno; Nardi-Dei, Vincenzo; Arcidiacono, Letizia; Mishra, Ravi P. N.; Mori, Elena; Pallaoro, Michele; Falugi, Fabiana; Torre, Antonina; Fontana, Maria Rita; Soriani, Marco; Bubeck Wardenburg, Juliane; Grandi, Guido; Rappuoli, Rino

    2016-01-01

    Staphylococcus aureus alpha-hemolysin (Hla) assembles into heptameric pores on the host cell membrane, causing lysis, apoptosis, and junction disruption. Herein, we present the design of a newly engineered S. aureus alpha-toxin, HlaPSGS, which lacks the predicted membrane-spanning stem domain. This protein is able to form heptamers in aqueous solution in the absence of lipophilic substrata, and its structure, obtained by transmission electron microscopy and single-particle reconstruction analysis, resembles the cap of the wild-type cytolytic Hla pore. HlaPSGS was found to be impaired in binding to host cells and to its receptor ADAM10 and to lack hemolytic and cytotoxic activity. Immunological studies using human sera as well as sera from mice convalescent from S. aureus infection suggested that the heptameric conformation of HlaPSGS mimics epitopes exposed by the cytolytic Hla pore during infection. Finally, immunization with this newly engineered Hla generated high protective immunity against staphylococcal infection in mice. Overall, this study provides unprecedented data on the natural immune response against Hla and suggests that the heptameric HlaPSGS is a highly valuable vaccine candidate against S. aureus. PMID:27030589

  18. Sphingopeptides: dihydrosphingosine-based fusion inhibitors against wild-type and enfuvirtide-resistant HIV-1.

    PubMed

    Ashkenazi, Avraham; Viard, Mathias; Unger, Linor; Blumenthal, Robert; Shai, Yechiel

    2012-11-01

    Understanding the structural organization of lipids in the cell and viral membranes is essential for elucidating mechanisms of viral fusion that lead to entry of enveloped viruses into their host cells. The HIV lipidome shows a remarkable enrichment in dihydrosphingomyelin, an unusual sphingolipid formed by a dihydrosphingosine backbone. Here we investigated the ability of dihydrosphingosine to incorporate into the site of membrane fusion mediated by the HIV envelope (Env) protein. Dihydrosphingosine as well as cholesterol, fatty acid, and tocopherol was conjugated to highly conserved, short HIV-1 Env-derived peptides with no antiviral activity otherwise. We showed that dihydrosphingosine exclusively endowed nanomolar antiviral activity to the peptides (IC(50) as low as 120 nM) in HIV-1 infection on TZM-bl cells and on Jurkat T cells, as well as in the cell-cell fusion assay. These sphingopeptides were active against enfuvirtide-resistant and wild-type CXCR4 and CCR5 tropic HIV strains. The anti-HIV activity was determined by both the peptides and their dihydrosphingosine conjugate. Moreover, their mode of action involved accumulation in the cells and viruses and binding to membranes enriched in sphingomyelin and cholesterol. The data suggest that sphingopeptides are recruited to the HIV membrane fusion site and provide a general concept in developing inhibitors of sphingolipid-mediated biological systems. PMID:22872679

  19. Rootcap structure in wild type and in a starchless mutant of Arabidopsis

    NASA Technical Reports Server (NTRS)

    Sack, F. D.; Kiss, J. Z.

    1989-01-01

    Rootcaps of the wild type (WT) and of a starchless, gravitropic mutant (TC7) of Arabidopsis thaliana L. were examined by electron microscopy to identify cellular polarities with respect to gravity. In columella cells, nuclei are located proximally, and the nuclear envelope is continuous with endoplasmic reticulum (ER) that is in turn connected to nearby plasmodesmata. Impregnation of ER with osmium ferricyanide revealed numerous contacts between columella plastids and ER in both genotypes. ER is present mostly in the outer regions of the columella protoplast except in older columella cells that are developing into peripheral cells. In vertical roots, only columella cells that are intermediate in development (story 2 cells) have a higher surface density (S) of ER in the distal compared to proximal regions of the cell. The distal but not the proximal S of the ER is constant throughout columella development. Plastids are less sedimented in TC7 columella cells compared to those of the WT. It is hypothesized that plastid contact with the ER plays a role in gravity perception in both genotypes.

  20. Wild-Type Transthyretin Cardiac Amyloidosis: Novel Insights From Advanced Imaging.

    PubMed

    Narotsky, David L; Castano, Adam; Weinsaft, Jonathan W; Bokhari, Sabahat; Maurer, Mathew S

    2016-09-01

    Amyloidosis is caused by extracellular deposition of abnormal protein fibrils, resulting in destruction of tissue architecture and impairment of organ function. The most common forms of systemic amyloidosis are light-chain and transthyretin-related (ATTR). ATTR can result from an autosomal dominant hereditary transmission of mutated genes in the transthyretin or from a wild-type form of disease (ATTRwt), previously known as senile cardiac amyloidosis. With the aging of the worldwide population, ATTRwt will emerge as the most common type of cardiac amyloidosis that clinicians encounter. Diagnosis of systemic amyloidosis is often delayed, either because of the false assumption that it is a rare disease, or because of misdiagnosis as a result of mistaking it with other conditions. Clinicians must integrate clinical clues from history, physical examination, and common diagnostic tests to raise suspicion for ATTRwt. The historical gold standard for diagnosis of cardiac amyloid is endomyocardial biopsy analysis with pathological distinction of precursor protein type, but this method often results in delayed diagnosis because of the limited availability of expertise to perform and interpret the endomyocardial biopsy specimen. Emerging noninvasive imaging modalities provide easier, accurate screening for ATTRwt. These modalities include advanced echocardiography, using strain imaging and the myocardial contraction fraction; nuclear scintigraphy, which can differentiate between ATTR and light-chain cardiac amyloid; and cardiac magnetic resonance imaging, using extracellular volume measurement, late gadolinium enhancement, and distinct T1 mapping. These novel approaches reveal insights into the prevalence, clinical course, morphological effects, and prognosis of ATTRwt. PMID:27568874

  1. Profile of Cytokines and Chemokines Triggered by Wild-Type Strains of Rabies Virus in Mice.

    PubMed

    Appolinário, Camila Michele; Allendorf, Susan Dora; Peres, Marina Gea; Ribeiro, Bruna Devidé; Fonseca, Clóvis R; Vicente, Acácia Ferreira; Antunes, João Marcelo A de Paula; Megid, Jane

    2016-02-01

    Rabies is a lethal infectious disease that causes 55,000 human deaths per year and is transmitted by various mammalian species, such as dogs and bats. The host immune response is essential for avoiding viral progression and promoting viral clearance. Cytokines and chemokines are crucial in the development of an immediate antiviral response; the rabies virus (RABV) attempts to evade this immune response. The virus's capacity for evasion is correlated with its pathogenicity and the host's inflammatory response, with highly pathogenic strains being the most efficient at hijacking the host's defense mechanisms and thereby decreasing inflammation. The purpose of this study was to evaluate the expression of a set of cytokine and chemokine genes that are related to the immune response in the brains of mice inoculated intramuscularly or intracerebrally with two wild-type strains of RABV, one from dog and the other from vampire bat. The results demonstrated that the gene expression profile is intrinsic to the specific rabies variant. The prompt production of cytokines and chemokines seems to be more important than their levels of expression for surviving a rabies infection. PMID:26711511

  2. Evaluation of short-interfering RNAs treatment in experimental rabies due to wild-type virus.

    PubMed

    Appolinario, Camila Michele; Allendorf, Susan Dora; Peres, Marina Gea; Fonseca, Clovis Reynaldo; Vicente, Acacia Ferreira; Antunes, João Marcelo Azevedo de Paula; Pantoja, José Carlos Figueiredo; Megid, Jane

    2015-01-01

    We have evaluated the efficacy of short-interfering RNAs targeting the nucleoprotein gene and also the brain immune response in treated and non-treated infected mice. Mice were inoculated with wild-type virus, classified as dog (hv2) or vampire bat (hv3) variants and both groups were treated or left as controls. No difference was observed in the lethality rate between treated and non-treated groups, although clinical evaluation of hv2 infected mice showed differences in the severity of clinical disease (p=0.0006). Evaluation of brain immune response 5 days post-inoculation in treated hv2 group showed no difference among the analyzed genes, whereas after 10 days post-inoculation there was increased expression of 2',5'-oligoadenylate synthetase 1, tumor necrosis factor alpha, interleukin 12, interferon gamma, and C-X-C motif chemokine 10 associated with higher expression of N gene in the same period (p<0.0001). In hv2 non-treated group only higher interferon beta expression was found at day 5. The observed differences in results of the immune response genes between treated and non-treated groups is not promising as they had neither impact on mortality nor even a reduction in the expression of N gene in siRNA treated animals. This finding suggests that the use of pre-designed siRNA alone may not be useful in rabies treatment. PMID:26254692

  3. Experimental Infection of Adults With Recombinant Wild-Type Human Metapneumovirus

    PubMed Central

    Talaat, Kawsar R.; Karron, Ruth A.; Thumar, Bhagvanji; McMahon, Bridget A.; Schmidt, Alexander C.; Collins, Peter L.; Buchholz, Ursula J.

    2013-01-01

    Background. Human metapneumovirus (HMPV) causes lower respiratory tract infections in young children. rHMPV-SHs is a recombinant HMPV (rHMPV) based on a biologically derived wild-type HMPV strain. We characterized its infectivity and immunogenicity in healthy adults to determine whether it would be suitable for use as the parent virus for the development of live attenuated rHMPV vaccines. Methods. Twenty-one healthy adults were inoculated intranasally with 106 plaque-forming units of rHMPV-SHs. Respiratory symptoms and shedding of challenge virus were assessed. Neutralizing antibody responses, serum immunoglobulin G and A, and nasal wash specimen immunoglobulin A antibody responses to the HMPV F protein were also measured. Induction of nasal cytokines was assessed with electrochemiluminescence assays. Results. Nine subjects (43%) were infected with challenge virus as determined by virus detection and/or ≥4-fold rise in serum antibody titers. Peak viral shedding occurred on days 7–9 after infection. Four weeks after inoculation, 35% of subjects had any antibody response. Six of 9 infected subjects had respiratory symptoms, and 3 had headache after inoculation. Cytokine patterns differed considerably between subjects with similar illness severity and viral shedding. Conclusions. The rHMPV-SHs virus is infectious and is a suitable parent virus for development of live-attenuated HMPV vaccine candidates. Clinical Trials Registration. NCT01109329. PMID:23908489

  4. Wild Type Bone Marrow Transplant Partially Reverses Neuroinflammation in Progranulin-Deficient Mice

    PubMed Central

    Yang, Yue; Aloi, Macarena S.; Cudaback, Eiron; Josephsen, Samuel R.; Rice, Samantha J.; Jorstad, Nikolas L.; Keene, C. Dirk; Montine, Thomas J.

    2014-01-01

    Frontotemporal dementia (FTD) is a neurodegenerative disease with devastating changes in behavioral performance and social function. Mutations in the progranulin gene (GRN) are one of the most common causes of inherited FTD due to reduced progranulin expression or activity, including in brain where it is expressed primarily by neurons and microglia. Thus, efforts aimed at enhancing progranulin levels might be a promising therapeutic strategy. Bone marrow-derived cells are able to engraft in the brain and adopt a microglial phenotype under myeloablative irradiation conditioning. This ability makes bone marrow (BM)-derived cells a potential cellular vehicle for transferring therapeutic molecules to the central nervous system. Here, we utilized BM cells from Grn+/+ (wild type or wt) mice labeled with green fluorescence protein for delivery of progranulin to progranulin deficient (Grn−/−) mice. Our results showed that wt bone marrow transplantation (BMT) partially reconstituted progranulin in the periphery and in cerebral cortex of Grn−/− mice. We demonstrated a pro-inflammatory effect in vivo and in ex vivo preparations of cerebral cortex of Grn−/− mice that was partially to fully reversed five months after BMT. Our findings suggest that BMT can be administered as a stem cell-based approach to prevent or to treat neurodegenerative diseases. PMID:25199051

  5. Auto-Assembling Detoxified Staphylococcus aureus Alpha-Hemolysin Mimicking the Wild-Type Cytolytic Toxin.

    PubMed

    Fiaschi, Luigi; Di Palo, Benedetta; Scarselli, Maria; Pozzi, Clarissa; Tomaszewski, Kelly; Galletti, Bruno; Nardi-Dei, Vincenzo; Arcidiacono, Letizia; Mishra, Ravi P N; Mori, Elena; Pallaoro, Michele; Falugi, Fabiana; Torre, Antonina; Fontana, Maria Rita; Soriani, Marco; Bubeck Wardenburg, Juliane; Grandi, Guido; Rappuoli, Rino; Ferlenghi, Ilaria; Bagnoli, Fabio

    2016-06-01

    Staphylococcus aureus alpha-hemolysin (Hla) assembles into heptameric pores on the host cell membrane, causing lysis, apoptosis, and junction disruption. Herein, we present the design of a newly engineered S. aureus alpha-toxin, HlaPSGS, which lacks the predicted membrane-spanning stem domain. This protein is able to form heptamers in aqueous solution in the absence of lipophilic substrata, and its structure, obtained by transmission electron microscopy and single-particle reconstruction analysis, resembles the cap of the wild-type cytolytic Hla pore. HlaPSGS was found to be impaired in binding to host cells and to its receptor ADAM10 and to lack hemolytic and cytotoxic activity. Immunological studies using human sera as well as sera from mice convalescent from S. aureus infection suggested that the heptameric conformation of HlaPSGS mimics epitopes exposed by the cytolytic Hla pore during infection. Finally, immunization with this newly engineered Hla generated high protective immunity against staphylococcal infection in mice. Overall, this study provides unprecedented data on the natural immune response against Hla and suggests that the heptameric HlaPSGS is a highly valuable vaccine candidate against S. aureus. PMID:27030589

  6. Mitochondrially targeted wild-type p53 induces apoptosis in a solid human tumor xenograft model

    PubMed Central

    Palacios, Gustavo; Crawford, Howard C.; Vaseva, Angelina; Moll, Ute M.

    2013-01-01

    Classic but also novel roles of p53 are becoming increasingly well characterized. We previously showed that ex vivo retroviral transfer of mitochondrially targeted wild type p53 (mitop53) in the Eμ-myc mouse lymphoma model efficiently induces tumor cell killing in vivo. In an effort to further explore the therapeutic potential of mitop53 for its pro-apoptotic effect in solid tumors, we generated replication-deficient recombinant human Adenovirus type 5 vectors. We show here that adenoviral delivery of mitop53 by intratumoral injection into HCT116 human colon carcinoma xenograft tumors in nude mice is surprisingly effective, resulting in tumor cell death of comparable potency to conventional p53. These apoptotic effects in vivo were confirmed by Ad5-mitop53 mediated cell death of HCT116 cells in culture. Together, these data provide encouragement to further explore the potential for novel mitop53 proteins in cancer therapy to execute the shortest known circuitry of p53 death signaling. PMID:18719383

  7. Extensive degradation of RNA precursors by the exosome in wild-type cells.

    PubMed

    Gudipati, Rajani Kanth; Xu, Zhenyu; Lebreton, Alice; Séraphin, Bertrand; Steinmetz, Lars M; Jacquier, Alain; Libri, Domenico

    2012-11-01

    The exosome is a complex involved in the maturation of rRNA and sn-snoRNA, in the degradation of short-lived noncoding RNAs, and in the quality control of RNAs produced in mutants. It contains two catalytic subunits, Rrp6p and Dis3p, whose specific functions are not fully understood. We analyzed the transcriptome of combinations of Rrp6p and Dis3p catalytic mutants by high-resolution tiling arrays. We show that Dis3p and Rrp6p have both overlapping and specific roles in degrading distinct classes of substrates. We found that transcripts derived from more than half of intron-containing genes are degraded before splicing. Surprisingly, we also show that the exosome degrades large amounts of tRNA precursors despite the absence of processing defects. These results underscore the notion that large amounts of RNAs produced in wild-type cells are discarded before entering functional pathways and suggest that kinetic competition with degradation proofreads the efficiency and accuracy of processing. PMID:23000176

  8. Quantification of gait parameters in freely walking wild type and sensory deprived Drosophila melanogaster

    PubMed Central

    Mendes, César S; Bartos, Imre; Akay, Turgay; Márka, Szabolcs; Mann, Richard S

    2013-01-01

    Coordinated walking in vertebrates and multi-legged invertebrates such as Drosophila melanogaster requires a complex neural network coupled to sensory feedback. An understanding of this network will benefit from systems such as Drosophila that have the ability to genetically manipulate neural activities. However, the fly's small size makes it challenging to analyze walking in this system. In order to overcome this limitation, we developed an optical method coupled with high-speed imaging that allows the tracking and quantification of gait parameters in freely walking flies with high temporal and spatial resolution. Using this method, we present a comprehensive description of many locomotion parameters, such as gait, tarsal positioning, and intersegmental and left-right coordination for wild type fruit flies. Surprisingly, we find that inactivation of sensory neurons in the fly's legs, to block proprioceptive feedback, led to deficient step precision, but interleg coordination and the ability to execute a tripod gait were unaffected. DOI: http://dx.doi.org/10.7554/eLife.00231.001 PMID:23326642

  9. Comparative whole genome sequence analysis of wild-type and cidofovir-resistant monkeypoxvirus

    PubMed Central

    2010-01-01

    We performed whole genome sequencing of a cidofovir {[(S)-1-(3-hydroxy-2-phosphonylmethoxy-propyl) cytosine] [HPMPC]}-resistant (CDV-R) strain of Monkeypoxvirus (MPV). Whole-genome comparison with the wild-type (WT) strain revealed 55 single-nucleotide polymorphisms (SNPs) and one tandem-repeat contraction. Over one-third of all identified SNPs were located within genes comprising the poxvirus replication complex, including the DNA polymerase, RNA polymerase, mRNA capping methyltransferase, DNA processivity factor, and poly-A polymerase. Four polymorphic sites were found within the DNA polymerase gene. DNA polymerase mutations observed at positions 314 and 684 in MPV were consistent with CDV-R loci previously identified in Vaccinia virus (VACV). These data suggest the mechanism of CDV resistance may be highly conserved across Orthopoxvirus (OPV) species. SNPs were also identified within virulence genes such as the A-type inclusion protein, serine protease inhibitor-like protein SPI-3, Schlafen ATPase and thymidylate kinase, among others. Aberrant chain extension induced by CDV may lead to diverse alterations in gene expression and viral replication that may result in both adaptive and attenuating mutations. Defining the potential contribution of substitutions in the replication complex and RNA processing machinery reported here may yield further insight into CDV resistance and may augment current therapeutic development strategies. PMID:20509894

  10. Differential transcription patterns in wild-type and glycoprotein G-deleted infectious laryngotracheitis viruses.

    PubMed

    Mahmoudian, Alireza; Markham, Philip F; Noormohammadi, Amir H; Devlin, Joanne M; Browning, Glenn F

    2013-01-01

    Infectious laryngotracheitis virus (ILTV) causes severe respiratory disease in poultry throughout the world. Recently the role of glycoprotein G (gG) in ILTV pathogenesis has been investigated and it has been shown to have chemokine-binding activity. An ILTV vaccine candidate deficient in gG has been developed and the deletion has been shown to alter the host's immune response to the virus. To understand the effect of the gG gene on transcription of other viral genes, the global expression profile of 72 ILTV genes in gG-deleted and wild-type ILTVs were investigated both in vivo and in vitro using quantitative reverse transcription-polymerase chain reaction. Several genes were differentially expressed in the different viruses in LMH cell cultures or in the tracheas of infected birds, and the expression of a number of genes, including ICP27, gC, gJ, Ul7 and UL40, differed significantly both in vivo and in vitro, suggesting that they had direct or indirect roles in virulence. This study has provided insights into the interactions between gG and other ILTV genes that may have a role in virulence. PMID:23611157

  11. Taste responses to sweet stimuli in alpha-gustducin knockout and wild-type mice.

    PubMed

    Danilova, Vicktoria; Damak, Sami; Margolskee, Robert F; Hellekant, Göran

    2006-07-01

    The importance of alpha-gustducin in sweet taste transduction is based on data obtained with sucrose and the artificial sweetener SC45647. Here we studied the role of alpha-gustducin in sweet taste. We compared the behavioral and electrophysiological responses of alpha-gustducin knockout (KO) and wild-type (WT) mice to 11 different sweeteners, representing carbohydrates, artificial sweeteners, and sweet amino acids. In behavioral experiments, over 48-h preference ratios were measured in two-bottle preference tests. In electrophysiological experiments, integrated responses of chorda tympani (CT) and glossopharyngeal (NG) nerves were recorded. We found that preference ratios of the KO mice were significantly lower than those of WT for acesulfame-K, dulcin, fructose, NC00174, D-phenylalanine, L-proline, D-tryptophan, saccharin, SC45647, sucrose, but not neotame. The nerve responses to all sweeteners, except neotame, were smaller in the KO mice than in the WT mice. The differences between the responses in WT and KO mice were more pronounced in the CT than in the NG. These data indicate that alpha-gustducin participates in the transduction of the sweet taste in general. PMID:16740645

  12. Intraperitoneal Infection of Wild-Type Mice with Synthetically Generated Mammalian Prion

    PubMed Central

    Wang, Xinhe; McGovern, Gillian; Zhang, Yi; Wang, Fei; Zha, Liang; Jeffrey, Martin; Ma, Jiyan

    2015-01-01

    The prion hypothesis postulates that the infectious agent in transmissible spongiform encephalopathies (TSEs) is an unorthodox protein conformation based agent. Recent successes in generating mammalian prions in vitro with bacterially expressed recombinant prion protein provide strong support for the hypothesis. However, whether the pathogenic properties of synthetically generated prion (rec-Prion) recapitulate those of naturally occurring prions remains unresolved. Using end-point titration assay, we showed that the in vitro prepared rec-Prions have infectious titers of around 104 LD50 / μg. In addition, intraperitoneal (i.p.) inoculation of wild-type mice with rec-Prion caused prion disease with an average survival time of 210 – 220 days post inoculation. Detailed pathological analyses revealed that the nature of rec-Prion induced lesions, including spongiform change, disease specific prion protein accumulation (PrP-d) and the PrP-d dissemination amongst lymphoid and peripheral nervous system tissues, the route and mechanisms of neuroinvasion were all typical of classical rodent prions. Our results revealed that, similar to naturally occurring prions, the rec-Prion has a titratable infectivity and is capable of causing prion disease via routes other than direct intra-cerebral challenge. More importantly, our results established that the rec-Prion caused disease is pathogenically and pathologically identical to naturally occurring contagious TSEs, supporting the concept that a conformationally altered protein agent is responsible for the infectivity in TSEs. PMID:26136122

  13. Fermentative production of 1-propanol from sugars using wild-type and recombinant Shimwellia blattae.

    PubMed

    Urano, Nobuyuki; Fujii, Misaki; Kaino, Hiroshi; Matsubara, Mitsuru; Kataoka, Michihiko

    2015-02-01

    Shimwellia blattae is an enteric bacterium and produces endogenous enzymes that convert 1,2-propanediol (1,2-PD) to 1-propanol, which is expected to be used as a fuel substitute and a precursor of polypropylene. Therefore, if S. blattae could be induced to generate its own 1,2-PD from sugars, it might be possible to produce 1-propanol from sugars with this microorganism. Here, two 1,2-PD production pathways were constructed in S. blattae, resulting in two methods for 1-propanol production with the bacterium. One method employed the L-rhamnose utilization pathway, in which L-rhamnose is split into dihydroxyacetone phosphate and 1,2-PD. When wild-type S. blattae was cultured with L-rhamnose, an accumulation of 1,2-PD was observed. The other method for producing 1,2-PD was to introduce an engineered 1,2-PD production pathway from glucose into S. blattae. In both cases, the produced 1,2-PD was then converted to 1-propanol by 1,2-PD converting enzymes, whose production was induced by the addition of glycerol. PMID:25547843

  14. Experimentally Derived Structural Constraints for Amyloid Fibrils of Wild-Type Transthyretin

    PubMed Central

    Bateman, David A.; Tycko, Robert; Wickner, Reed B.

    2011-01-01

    Transthyretin (TTR) is a largely β-sheet serum protein responsible for transporting thyroxine and vitamin A. TTR is found in amyloid deposits of patients with senile systemic amyloidosis. TTR mutants lead to familial amyloidotic polyneuropathy and familial amyloid cardiomyopathy, with an earlier age of onset. Studies of amyloid fibrils of familial amyloidotic polyneuropathy mutant TTR suggest a structure similar to the native state with only a simple opening of a β-strand-loop-strand region exposing the two main β-sheets of the protein for fibril elongation. However, we find that the wild-type TTR sequence forms amyloid fibrils that are considerably different from the previously suggested amyloid structure. Using protease digestion with mass spectrometry, we observe the amyloid core to be primarily composed of the C-terminal region, starting around residue 50. Solid-state NMR measurements prove that TTR differs from other pathological amyloids in not having an in-register parallel β-sheet architecture. We also find that the TTR amyloid is incapable of binding thyroxine as monitored by either isothermal calorimetry or 1,8-anilinonaphthalene sulfonate competition. Taken together, our experiments are consistent with a significantly different configuration of the β-sheets compared to the previously suggested structure. PMID:22098747

  15. Experimentally derived structural constraints for amyloid fibrils of wild-type transthyretin.

    PubMed

    Bateman, David A; Tycko, Robert; Wickner, Reed B

    2011-11-16

    Transthyretin (TTR) is a largely β-sheet serum protein responsible for transporting thyroxine and vitamin A. TTR is found in amyloid deposits of patients with senile systemic amyloidosis. TTR mutants lead to familial amyloidotic polyneuropathy and familial amyloid cardiomyopathy, with an earlier age of onset. Studies of amyloid fibrils of familial amyloidotic polyneuropathy mutant TTR suggest a structure similar to the native state with only a simple opening of a β-strand-loop-strand region exposing the two main β-sheets of the protein for fibril elongation. However, we find that the wild-type TTR sequence forms amyloid fibrils that are considerably different from the previously suggested amyloid structure. Using protease digestion with mass spectrometry, we observe the amyloid core to be primarily composed of the C-terminal region, starting around residue 50. Solid-state NMR measurements prove that TTR differs from other pathological amyloids in not having an in-register parallel β-sheet architecture. We also find that the TTR amyloid is incapable of binding thyroxine as monitored by either isothermal calorimetry or 1,8-anilinonaphthalene sulfonate competition. Taken together, our experiments are consistent with a significantly different configuration of the β-sheets compared to the previously suggested structure. PMID:22098747

  16. Gravitropism and development of wild-type and starch-deficient mutants of Arabidopsis during spaceflight

    NASA Technical Reports Server (NTRS)

    Kiss, J. Z.; Katembe, W. J.; Edelmann, R. E.

    1998-01-01

    The "starch-statolith" hypothesis has been used by plant physiologists to explain the gravity perception mechanism in higher plants. In order to help resolve some of the controversy associated with ground-based research that has supported this theory, we performed a spaceflight experiment during the January 1997 mission of the Space Shuttle STS-81. Seedlings of wild-type (WT) Arabidopsis, two reduced-starch strains, and a starchless mutant were grown in microgravity and then given a gravity stimulus on a centrifuge. In terms of development in space, germination was greater than 90% for seeds in microgravity, and flight seedlings were smaller (60% in total length) compared to control plants grown on the ground and to control plants on a rotating clinostat. Seedlings grown in space had two structural features that distinguished them from the controls: a greater density of root hairs and an anomalous hypocotyl hook structure. However, the slower growth and morphological changes observed in the flight seedlings may be due to the effects of ethylene present in the spacecraft. Nevertheless, during the flight hypocotyls of WT seedlings responded to a unilateral 60 min stimulus provided by a 1-g centrifuge while those of the starch-deficient strains did not. Thus the strain with the greatest amount of starch responded to the stimulus given in flight and therefore, these data support the starch-statolith model for gravity sensing.

  17. Pharmacologic activation of wild-type p53 by nutlin therapy in childhood cancer.

    PubMed

    Van Maerken, Tom; Rihani, Ali; Van Goethem, Alan; De Paepe, Anne; Speleman, Frank; Vandesompele, Jo

    2014-03-28

    A peculiar feature of several types of childhood cancer is that loss-of-function mutations of the TP53 (p53) tumor suppressor gene are uncommon, in contrast to many adult tumors. As p53 needs to be inactivated in order for tumor cells to survive and thrive, pediatric tumors typically make use of other mechanisms to keep p53 in check. One of the critical negative regulators of p53 is the MDM2 oncoprotein. Many anticancer drug development efforts in the past decade have therefore been devoted to the discovery and optimization of small molecules that selectively disrupt the interaction between MDM2 and p53, which could provide, in principle, a potent means to restore p53 function in tumor cells with wild-type p53. The nutlins are the class of selective inhibitors of the p53-MDM2 interaction that are currently most advanced in their clinical development. We review here the preclinical data that support the potential therapeutic use of nutlin drugs in the treatment of various pediatric tumors, including neuroblastoma, retinoblastoma, osteosarcoma, Ewing's sarcoma, rhabdomyosarcoma, medulloblastoma, and childhood acute lymphoblastic leukemia. PMID:24262662

  18. Wild type microglia do not arrest pathology in mouse models of Rett syndrome

    PubMed Central

    Wang, Jieqi; Wegener, Jan Eike; Huang, Teng-Wei; Sripathy, Smitha; De Jesus-Cortes, Hector; Xu, Pin; Tran, Stephanie; Knobbe, Whitney; Leko, Vid; Britt, Jeremiah; Starwalt, Ruth; McDaniel, Latisha; Ward, Chris; Parra, Diana; Newcomb, Benjamin; Lao, Uyen; Flowers, David A.; Cullen, Sean; Jorstad, Nikolas L; Yang, Yue; Glaskova, Lena; Vigneau, Sebastian; Kozlitina, Julia; Reichardt, Sybille D.; Reichardt, Holger M.; Gärtner, Jutta; Bartolomei, Marisa S.; Fang, Min; Loeb, Keith; Keene, C. Dirk; Bernstein, Irwin; Goodell, Margaret; Brat, Daniel J.

    2015-01-01

    Rett syndrome (RTT) is a severe neurodevelopmental disorder caused by mutations in the X chromosomal gene Methyl-CpG-binding Protein 2 (MECP2) (1). RTT treatment so far is symptomatic. Mecp2 disruption in mice phenocopies major features of the syndrome (2) that can be reversed upon re-expression of Mecp2 (3. It has recently been reported that transplantation of wild type (WT) bone marrow (BMT) into lethally irradiated Mecp2tm1.1Jae/y mice prevented neurologic decline and early death by restoring microglial phagocytic activity against apoptotic targets (4). Based on this report, clinical trials of BMT for patients with RTT have been initiated (5). We aimed to replicate and extend the BMT experiments in three different RTT mouse models but found that despite robust microglial engraftment, BMT from WT donors did not rescue early death or ameliorate neurologic deficits. Furthermore, early and specific genetic expression of Mecp2 in microglia did not rescue Mecp2-deficient mice. In conclusion our experiments do not support BMT as therapy for RTT. PMID:25993969

  19. Dietary supplementation with ipriflavone decreases hepatic iron stores in wild type mice.

    PubMed

    Patchen, Bonnie; Koppe, Tiago; Cheng, Aaron; Seo, Young Ah; Wessling-Resnick, Marianne; Fraenkel, Paula G

    2016-09-01

    Hepcidin, a peptide produced in the liver, decreases intestinal iron absorption and macrophage iron release by causing degradation of the iron exporter, ferroportin. Because its levels are inappropriately low in patients with iron overload syndromes, hepcidin is a potential drug target. We previously conducted a chemical screen that revealed ipriflavone, an orally available small molecule, as a potent inducer of hepcidin expression. To evaluate ipriflavone's effect on iron homeostasis, we placed groups of 5-week old wild type or thalassemia intermedia (Hbb(Th3+/-)) mice on a soy-free, iron-sufficient diet, AIN-93G containing 220mg iron and 0-750mgipriflavone/kg of food for 50days. Ipriflavone 500mg/kg significantly reduced liver iron stores and intestinal ferroportin expression in WT mice, while increasing the ratio of hepcidin transcript levels to liver iron stores. Ipriflavone supplementation in Hbb(Th3+/-) mice failed to alleviate iron overload and was associated with a milder reduction in intestinal ferroportin and a failure to alter the ratio of hepcidin transcript levels to liver iron stores or splenic expression of the hepcidin-regulatory hormone, erythroferrone. These data suggest that dietary supplementation with ipriflavone alone would not be sufficient to treat iron overload in thalassemia intermedia. PMID:27519943

  20. Magnetic Resonance Spectroscopy discriminates the response to microglial stimulation of wild type and Alzheimer's disease models.

    PubMed

    Pardon, Marie-Christine; Yanez Lopez, Maria; Yuchun, Ding; Marjańska, Małgorzata; Prior, Malcolm; Brignell, Christopher; Parhizkar, Samira; Agostini, Alessandra; Bai, Li; Auer, Dorothee P; Faas, Henryk M

    2016-01-01

    Microglia activation has emerged as a potential key factor in the pathogenesis of Alzheimer's disease. Metabolite levels assessed by magnetic resonance spectroscopy (MRS) are used as markers of neuroinflammation in neurodegenerative diseases, but how they relate to microglial activation in health and chronic disease is incompletely understood. Using MRS, we monitored the brain metabolic response to lipopolysaccharides (LPS)-induced microglia activation in vivo in a transgenic mouse model of Alzheimer's disease (APP/PS1) and healthy controls (wild-type (WT) littermates) over 4 hours. We assessed reactive gliosis by immunohistochemistry and correlated metabolic and histological measures. In WT mice, LPS induced a microglial phenotype consistent with activation, associated with a sustained increase in macromolecule and lipid levels (ML9). This effect was not seen in APP/PS1 mice, where LPS did not lead to a microglial response measured by histology, but induced a late increase in the putative inflammation marker myoinositol (mI) and metabolic changes in total creatine and taurine previously reported to be associated with amyloid load. We argue that ML9 and mI distinguish the response of WT and APP/PS1 mice to immune mediators. Lipid and macromolecule levels may represent a biomarker of activation of healthy microglia, while mI may not be a glial marker. PMID:26813748

  1. Biochemical characterization of Arabidopsis wild-type and mutant phytochrome B holoproteins.

    PubMed Central

    Elich, T D; Chory, J

    1997-01-01

    Although phytochrome B (phyB) plays a particularly important role throughout the life cycle of a plant, it has not been studied in detail at the molecular level due to its low abundance. Here, we report on the expression, assembly with chromophore, and purification of epitope-tagged Arabidopsis phyB. In addition, we have reconstructed two missense mutations, phyB-4 and phyB-101, isolated in long hypocotyl screens. We show that mutant proteins phyB-4 and phyB-101 exhibit altered spectrophotometric and biochemical properties relative to the wild-type protein. In particular, we demonstrate that phyB-101 Pfr exhibits rapid nonphotochemical (dark) reversion to Pr that results in a lower photoequilibrium level of the active Pfr form. We conclude that this occurs in vivo as well because phyB-101 mutants are shown to lack an end-of-day-far-red hypocotyl elongation response that requires a stable Pfr species. We propose that this Pfr instability may be the primary molecular mechanism underlying the phyB-101 mutant phenotype. PMID:9437866

  2. The mechanical properties of Drosophila jump muscle expressing wild-type and embryonic Myosin isoforms.

    PubMed

    Eldred, Catherine C; Simeonov, Dimitre R; Koppes, Ryan A; Yang, Chaoxing; Corr, David T; Swank, Douglas M

    2010-04-01

    Transgenic Drosophila are highly useful for structure-function studies of muscle proteins. However, our ability to mechanically analyze transgenically expressed mutant proteins in Drosophila muscles has been limited to the skinned indirect flight muscle preparation. We have developed a new muscle preparation using the Drosophila tergal depressor of the trochanter (TDT or jump) muscle that increases our experimental repertoire to include maximum shortening velocity (V(slack)), force-velocity curves and steady-state power generation; experiments not possible using indirect flight muscle fibers. When transgenically expressing its wild-type myosin isoform (Tr-WT) the TDT is equivalent to a very fast vertebrate muscle. TDT has a V(slack) equal to 6.1 +/- 0.3 ML/s at 15 degrees C, a steep tension-pCa curve, isometric tension of 37 +/- 3 mN/mm(2), and maximum power production at 26% of isometric tension. Transgenically expressing an embryonic myosin isoform in the TDT muscle increased isometric tension 1.4-fold, but decreased V(slack) 50% resulting in no significant difference in maximum power production compared to Tr-WT. Drosophila expressing embryonic myosin jumped <50% as far as Tr-WT that, along with comparisons to frog jump muscle studies, suggests fast muscle shortening velocity is relatively more important than high tension generation for Drosophila jumping. PMID:20371321

  3. The Resistant-Population Cutoff (RCOFF): a New Concept for Improved Characterization of Antimicrobial Susceptibility Patterns of Non-Wild-Type Bacterial Populations

    PubMed Central

    Valsesia, Giorgia; Hombach, Michael; Maurer, Florian P.; Courvalin, Patrice; Roos, Malgorzata

    2015-01-01

    This study aimed to determine resistant-population cutoffs (RCOFFs) to allow for improved characterization of antimicrobial susceptibility patterns in bacterial populations. RCOFFs can complement epidemiological cutoff (ECOFF)-based settings of clinical breakpoints (CBPs) by systematically describing the correlation between non-wild-type and wild-type populations. We illustrate this concept by describing three paradigmatic examples of wild-type and non-wild-type Escherichia coli populations from our clinical strain database of disk diffusion diameters. The statistical determination of RCOFFs and ECOFFs and their standardized applications in antimicrobial susceptibility testing (AST) facilitates the assignment of isolates to wild-type or non-wild-type populations. This should improve the correlation of in vitro AST data and distinct antibiotic resistance mechanisms with clinical outcome facilitating the setting and validation of CBPs. PMID:25762769

  4. Wild-type p53-mediated down-modulation of interleukin 15 and interleukin 15 receptors in human rhabdomyosarcoma cells.

    PubMed Central

    De Giovanni, C.; Nanni, P.; Sacchi, A.; Soddu, S.; Manni, I.; D'Orazi, G.; Bulfone-Paus, S.; Pohl, T.; Landuzzi, L.; Nicoletti, G.; Frabetti, F.; Rossi, I.; Lollini, P. L.

    1998-01-01

    We recently reported that rhabdomyosarcoma cell lines express and secrete interleukin 15 (IL-15), a tightly regulated cytokine with IL-2-like activity. To test whether the p53-impaired function that is frequently found in this tumour type could play a role in the IL-15 production, wild-type p53 gene was transduced in the human rhabdomyosarcoma cell line RD (which harbours a mutated p53 gene), and its effect on proliferation and expression of IL-15 was studied. Arrest of proliferation was induced by wild-type p53; increased proportions of G1-arrested cells and of apoptotic cells were observed. A marked down-modulation of IL-15 expression, at both the mRNA and protein level, was found in p53-transduced cells. Because a direct effect of IL-15 on normal muscle cells has been reported, the presence of IL-15 membrane receptors was studied by cytofluorometric analysis. Rhabdomyosarcoma cells showed IL-15 membrane receptors, which are down-modulated by wild-type p53 transfected gene. In conclusion, wild-type p53 transduction in human rhabdomyosarcoma cells induces the down-modulation of both IL-15 production and IL-15 receptor expression. Images Figure 3 PMID:9862562

  5. Differential proteomic responses of selectively bred and wild-type Sydney rock oyster populations exposed to elevated CO2.

    PubMed

    Thompson, E L; O'Connor, W; Parker, L; Ross, P; Raftos, D A

    2015-03-01

    Previous work suggests that larvae from Sydney rock oysters that have been selectively bred for fast growth and disease resistance are more resilient to the impacts of ocean acidification than nonselected, wild-type oysters. In this study, we used proteomics to investigate the molecular differences between oyster populations in adult Sydney rock oysters and to identify whether these form the basis for observations seen in larvae. Adult oysters from a selective breeding line (B2) and nonselected wild types (WT) were exposed for 4 weeks to elevated pCO2 (856 μatm) before their proteomes were compared to those of oysters held under ambient conditions (375 μatm pCO2 ). Exposure to elevated pCO2 resulted in substantial changes in the proteomes of oysters from both the selectively bred and wild-type populations. When biological functions were assigned, these differential proteins fell into five broad, potentially interrelated categories of subcellular functions, in both oyster populations. These functional categories were energy production, cellular stress responses, the cytoskeleton, protein synthesis and cell signalling. In the wild-type population, proteins were predominantly upregulated. However, unexpectedly, these cellular systems were downregulated in the selectively bred oyster population, indicating cellular dysfunction. We argue that this reflects a trade-off, whereby an adaptive capacity for enhanced mitochondrial energy production in the selectively bred population may help to protect larvae from the effects of elevated CO2 , whilst being deleterious to adult oysters. PMID:25689603

  6. A comparative study of cytokinins in caryopsis development in the maize miniature 1 seed mutant and its wild type

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report here a comparative developmental profile of cytokinins, both total quantity and diversity of various forms, in relation to cell size, cell number and endoreduplication in developing caryopses of a cell wall invertase-deficient miniature1 (mn1) seed mutant and its wild type, Mn1, genotype. ...

  7. Dendritic cells transduced with wild-type p53 gene elicit potent anti-tumour immune responses

    PubMed Central

    Ishida, T; Chada, S; Stipanov, M; Nadaf, S; Ciernik, F I; Gabrilovich, D I; Carbone, D P

    1999-01-01

    In this study we have tested the concept of using wild-type p53 gene for immunotherapy of cancer. Dendritic cells (DC) were transduced with a human wild-type p53 containing recombinant adenovirus (Ad-p53). About a half of DC transduced with this virus expressed p53 protein by FACS analysis 48 h after infection. Mice immunized twice with Ad-p53 DC developed substantial cytotoxic T lymphocyte (CTL) responses against tumour cells expressing wild-type and different mutant human and murine p53 genes. Very low CTL responses were observed against target cells infected with control adenovirus (Ad-c). Immunization with Ad-p53 provided complete tumour protection in 85% of mice challenged with tumour cells expressing human mutant p53 and in 72.7% of mice challenged with tumour cells with murine mutant p53. Treatment with Ad-p53-transduced DC significantly slowed the growth of established tumours. Thus, DC transduced with wild-type p53 may be a promising new tool for the immunotherapy of cancer. PMID:10444254

  8. Receptor usage and differential downregulation of CD46 by measles virus wild-type and vaccine strains.

    PubMed

    Schneider-Schaulies, J; Schnorr, J J; Brinckmann, U; Dunster, L M; Baczko, K; Liebert, U G; Schneider-Schaulies, S; ter Meulen, V

    1995-04-25

    Recently, two cell surface molecules, CD46 and moesin, have been found to be functionally associated with measles virus (MV) infectivity of cells. We investigated the receptor usage of MV wild-type, subacute sclerosing panencephalitis, and vaccine strains and their effect on the down-regulation of CD46 after infection. We found that the infection of human cell lines with all 19 MV strains tested was inhibitable with antibodies against CD46. In contrast, not all strains of MV led to the downregulation of CD46 following infection. The group of CD46 non-downregulating strains comprised four lymphotropic wild-type isolates designated AB, DF, DL, and WTF. Since the downregulation of CD46 is caused by interaction with newly synthesized MV hemagglutinin (MV-H), we tested the capability of recombinant MV-H proteins to downregulate CD46. Recombinant MV-H proteins of MV strains Edmonston, Halle, and CM led to the down-regulation of CD46, whereas those of DL and WTF did not. This observed differential downregulation by different MV strains has profound consequences, since lack of CD46 on the cell surface leads to susceptibility of cells to complement lysis. These results suggest that lymphotropic wild-type strains of MV which do not downregulate CD46 may have an advantage for replication in vivo. The relatively weak immune response against attenuated vaccine strains of MV compared with wild-type strains might be related to this phenomenon. PMID:7732009

  9. ASSESSING POTENTIAL OF COLLETOTRICHUM ACUTATUM WILD-TYPE AND AUXOTROPHIC MUTANTS AS BIOLOGICAL FRUIT THINNING AGENTS IN CITRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Colletotrichum acutatum, causal agent of postbloom fruit drop of citrus, and two induced C. acutatum mutants (3-3 and 3-2) were tested as potential agents for reducing fruit load on Valencia (Citrus sinensis ) and 'Temple' orange (C.reticulata x C. sinensis). Wild-type C. acutatum (RST) and a C. gl...

  10. Wild-Type Mouse Models to Screen Antisense Oligonucleotides for Exon-Skipping Efficacy in Duchenne Muscular Dystrophy

    PubMed Central

    Cao, Limin; Han, Gang; Gu, Ben; Yin, HaiFang

    2014-01-01

    A readily available animal model is essential for rapidly identifying effective treatments for Duchenne muscular dystrophy (DMD), a devastating neuromuscular disorder caused by the lack of dystrophin protein, which results from frame-disrupting mutations in the DMD gene. Currently, the mdx mouse is the most commonly used model for antisense oligonucleotide (AO)-mediated exon skipping pre-clinical studies, with a mild phenotype. However, the accessibility of mdx mouse colonies particularly in developing countries can constrain research. Therefore in this study we explore the feasibility of using wild-type mice as models to establish exon-skipping efficiency of various DMD AO chemistries and their conjugates. Four different strains of wild-type mice and six different AO chemistries were investigated intramuscularly and the results indicated that the same exon-skipping efficiency was achieved for all tested AOs as that from mdx mice. Notably, levels of exon-skipping obtained in C57BL6 and C3H and mdx mice were most closely matched, followed by ICR and BALB/C mice. Systemic validation revealed that wild-type mice are less responsive to AO-mediated exon skipping than mdx mice. Our study provides evidence for the first time that wild-type mice can be appropriate models for assessing DMD AO exon-skipping efficiency with similar sensitivity to that of mdx mice and this finding can further accelerate the development of effective DMD AOs. PMID:25365558

  11. Differences in 23S ribosomal RNA mutations between wild-type and mutant macrolide-resistant Chlamydia trachomatis isolates

    PubMed Central

    JIANG, YONG; ZHU, HUI; YANG, LI-NA; LIU, YUAN-JUN; HOU, SHU-PING; QI, MAN-LI; LIU, QUAN-ZHONG

    2015-01-01

    The aim of the present study was to determine the in vitro susceptibility of wild-type and mutant clinical isolates of Chlamydia (C.) trachomatis strains to erythromycin, azithromycin and josamycin, and to identify the resistance-conferring 23S ribosomal (r)RNA mutations in the isolates. The wild-type resistant isolates were defined as those with minimum inhibitory concentration values above the tissue concentration of the antibiotic in the urogenital system. Furthermore, all resistant C. trachomatis isolates were exposed to sub-inhibitory concentrations of macrolides, and 13 resistant mutants were selected following serial passages. Among the 8 wild-type isolates that were resistant to erythromycin, 3 isolates had a mutation at T2611C in the 23S rRNA gene while the others did not show any 23S rRNA mutations. The selected mutant isolates showed a 4- to 16-fold reduction in in vitro sensitivities. With regard to the mutant strains, the T2611C mutation was found in 10 isolates, A2057G mutation in 6 isolates, and A2059G mutation in 1 isolate. Thus, the macrolide-resistant isolates of the wild-type strain had different mutations from those selected by exposure to sub-inhibitory concentrations of macrolides. Also, since 23S rRNA mutations were not identified in certain isolates, it was considered that other molecular mechanisms may also be responsible for the macrolide resistance of C. trachomatis. PMID:26622462

  12. Prognostic and Predictive Significance of MYC and KRAS Alterations in Breast Cancer from Women Treated with Neoadjuvant Chemotherapy

    PubMed Central

    de Souza, Carolina Rosal Teixeira; Montenegro, Raquel Carvalho; Rey, Juan Antonio; Carvalho, Antônio Alberto; Assumpção, Paulo Pimentel; Khayat, André Salim; Pinto, Giovanny Rebouças; Demachki, Sâmia; de Arruda Cardoso Smith, Marília; Burbano, Rommel Rodríguez

    2013-01-01

    Breast cancer is a complex disease, with heterogeneous clinical evolution. Several analyses have been performed to identify the risk factors for breast cancer progression and the patients who respond best to a specific treatment. We aimed to evaluate whether the hormone receptor expression, HER2 and MYC genes and their protein status, and KRAS codon 12 mutations may be prognostic or predictive biomarkers of breast cancer. Protein, gene and mutation status were concomitantly evaluated in 116 breast tumors from women who underwent neoadjuvant chemotherapy with doxorubicin plus cyclophosphamide. We observed that MYC expression was associated with luminal B and HER2 overexpression phenotypes compared to luminal A (p<0.05). The presence of MYC duplication or polysomy 8, as well as KRAS mutation, were also associated with the HER2 overexpression subtype (p<0.05). MYC expression and MYC gain were more frequently observed in early-onset compared to late-onset tumors (p<0.05). KRAS mutation was a risk factor of grade 3 tumors (p<0.05). A multivariate logistic regression demonstrated that MYC amplification defined as MYC/nucleus ratio of ≥2.5 was a protective factor for chemotherapy resistance. On the other hand, age and grade 2 tumors were a risk factor. Additionally, luminal B, HER2 overexpression, and triple-negative tumors presented increased odds of being resistant to chemotherapy relative to luminal A tumors. Thus, breast tumors with KRAS codon 12 mutations seem to present a worse prognosis. Additionally, MYC amplification may help in the identification of tumors that are sensitive to doxorubicin plus cyclophosphamide treatment. If confirmed in a large set of samples, these markers may be useful for clinical stratification and prognosis. PMID:23555992

  13. Stimulus control by 5methoxy-N,N-dimethyltryptamine in wild-type and CYP2D6-humanized mice

    PubMed Central

    Winter, J. C.; Amorosi, D. J.; Rice, Kenner C.; Cheng, Kejun; Yu, Ai-Ming

    2011-01-01

    In previous studies we have observed that, in comparison with wild type mice, Tg-CYP2D6 mice have increased serum levels of bufotenine [5-hydroxy-N,N-dimethyltryptamine] following the administration of 5-MeO-DMT. Furthermore, following the injection of 5-MeO-DMT, harmaline was observed to increase serum levels of bufotenine and 5-MeO-DMT in both wild-type and Tg-CYP2D6 mice. In the present investigation, 5-MeO-DMT-induced stimulus control was established in wild-type and Tg-CYP2D6 mice. The two groups did not differ in their rate of acquisition of stimulus control. When tested with bufotenine, no 5-MeO-DMT-appropriate responding was observed. In contrast, the more lipid soluble analog of bufotenine, acetylbufotenine, was followed by an intermediate level of responding. The combination of harmaline with 5-MeO-DMT yielded a statistically significant increase in 5-MeO-DMT-appropriate responding in Tg-CYP2D6 mice; a comparable increase occurred in wild-type mice. In addition, it was noted that harmaline alone was followed by a significant degree of 5-MeO-DMT-appropriate responding in Tg-CYP2D6 mice. It is concluded that wild-type and Tg-CYPD2D6 mice do not differ in terms of acquisition of stimulus control by 5-MeO-DMT or in their response to bufotenine and acetylbufotenine. In both groups of mice, harmaline was found to enhance the stimulus effects of 5-MeO-DMT. PMID:21624387

  14. Functional differences in pore properties between wild-type and cysteine-less forms of the CFTR chloride channel.

    PubMed

    Holstead, Ryan G; Li, Man-Song; Linsdell, Paul

    2011-10-01

    Studies of the structure and function of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel have been advanced by the development of functional channel variants in which all 18 endogenous cysteine residues have been mutated ("cys-less" CFTR). However, cys-less CFTR has a slightly higher single-channel conductance than wild-type CFTR, raising questions as to the suitability of cys-less as a model of the wild-type CFTR pore. We used site-directed mutagenesis and patch-clamp recording to investigate the origin of this conductance difference and to determine the extent of functional differences between wild-type and cys-less CFTR channel permeation properties. Our results suggest that the conductance difference is the result of a single substitution, of C343: the point mutant C343S has a conductance similar to cys-less, whereas the reverse mutation, S343C in a cys-less background, restores wild-type conductance levels. Other cysteine substitutions (C128S, C225S, C376S, C866S) were without effect. Substitution of other residues for C343 suggested that conductance is dependent on amino acid side chain volume at this position. A range of other functional pore properties, including interactions with channel blockers (Au[CN] (2) (-) , 5-nitro-2-[3-phenylpropylamino]benzoic acid, suramin) and anion permeability, were not significantly different between wild-type and cys-less CFTR. Our results suggest that functional differences between these two CFTR constructs are of limited scale and scope and result from a small change in side chain volume at position 343. These results therefore support the use of cys-less as a model of the CFTR pore region. PMID:21796426

  15. Research on the ultrafast fluorescence property of thylakoid membranes of the wild-type and mutant rice

    NASA Astrophysics Data System (ADS)

    Ren, Zhao-Yu; Xu, Xiao-Ming; Wang, Shui-Cai; Xin, Yue-Yong; He, Jun-Fang; Hou, Xun

    2003-10-01

    A high yielding rice variety mutant (Oryza sativa L., Zhenhui 249) with low chlorophyll b (Chl b) has been discovered in natural fields. It has a quality character controlled by a pair of recessive genes (nuclear gene). The partial loss of Chl b in content affects the efficiency of light harvest in a light harvest complex (LHC), thus producing the difference of the exciting energy transfer and the efficiency of photochemistry conversion between the mutant and wild-type rice in photosynthetic unit. The efficiency of utilizing light energy is higher in the mutant than that in the wild-type rice relatively. For further discussion of the above-mentioned difference and learning about the mechanism of the increase in the photochemical efficiency of the mutant, the pico-second resolution fluorescence spectrum measurement with delay-frame-scanning single photon counting technique is adopted. Thylakoid membranes of the mutant and the wild-type rice are excited by an Ar+ laser with a pulse width of 120 ps, repetition rate of 4 MHz and wavelength of 514 nm. Compared with the time and spectrum property of exciting fluorescence, conclusions of those ultrafast dynamic experiments are: 1) The speeds of the exciting energy transferred in photo-system I are faster than that in photo-system II in both samples. 2) The speeds of the exciting energy transfer of mutant sample are faster than those of the wild-type. This might be one of the major reasons why the efficiency of photosynthesis is higher in mutant than that in the wild-type rice.

  16. Stimulus control by 5-methoxy-N,N-dimethyltryptamine in wild-type and CYP2D6-humanized mice.

    PubMed

    Winter, J C; Amorosi, D J; Rice, Kenner C; Cheng, Kejun; Yu, Ai-Ming

    2011-09-01

    In previous studies we have observed that, in comparison with wild type mice, Tg-CYP2D6 mice have increased serum levels of bufotenine [5-hydroxy-N,N-dimethyltryptamine] following the administration of 5-MeO-DMT. Furthermore, following the injection of 5-MeO-DMT, harmaline was observed to increase serum levels of bufotenine and 5-MeO-DMT in both wild-type and Tg-CYP2D6 mice. In the present investigation, 5-MeO-DMT-induced stimulus control was established in wild-type and Tg-CYP2D6 mice. The two groups did not differ in their rate of acquisition of stimulus control. When tested with bufotenine, no 5-MeO-DMT-appropriate responding was observed. In contrast, the more lipid soluble analog of bufotenine, acetylbufotenine, was followed by an intermediate level of responding. The combination of harmaline with 5-MeO-DMT yielded a statistically significant increase in 5-MeO-DMT-appropriate responding in Tg-CYP2D6 mice; a comparable increase occurred in wild-type mice. In addition, it was noted that harmaline alone was followed by a significant degree of 5-MeO-DMT-appropriate responding in Tg-CYP2D6 mice. It is concluded that wild-type and Tg-CYPD2D6 mice do not differ in terms of acquisition of stimulus control by 5-MeO-DMT or in their response to bufotenine and acetylbufotenine. In both groups of mice, harmaline was found to enhance the stimulus effects of 5-MeO-DMT. PMID:21624387

  17. Protein substrates for cGMP-dependent protein phosphorylation in cilia of wild type and atalanta mutants of Paramecium.

    PubMed

    Ann, K S; Nelson, D L

    1995-01-01

    In the ciliated protozoan Paramecium, swimming direction is regulated by voltage-gated Ca2+ channels in the ciliary membrane. In response to depolarizing stimuli, intraciliary Ca2+ rises, triggering reversal of the ciliary power stroke and backward swimming. One class of Ca(2+)-unresponsive behavioral mutants of Paramecium, atalanta mutants, cannot swim backward even though they have functional Ca2+ channels in their ciliary membrane. Several atalanta mutants were characterized with regard to several Ca(2+)-dependent activities, but no significant difference between wild type and the mutants was detected. However, one allelic group, atalanta A (initially characterized by Hinrichsen and Kung [1984: Genet. Res. Camb. 43:11-20]), showed a helical swimming path of opposite handedness from that of wild-type cells when detergent-permeabilized cells ("models") were reactivated with MgATP. When cGMP-dependent protein kinase purified from wild-type cells was added to atalanta A models, the handedness of the swimming path was reversed. Cyclic GMP stimulated in vitro phosphorylation of several proteins in isolated cilia, and the pattern of phosphoproteins was very similar for wild type and atalanta mutants, with one exception: a protein of 59 kDa was phosphorylated much less in the mutant ata A. When ciliary proteins were separated by gel electrophoresis and then phosphorylated "on blot" by purified cGMP-dependent protein kinase, phosphoprotein patterns were similar in wild type and ata mutants except that a 48 kDa protein (p48) from ata A3 was more heavily phosphorylated. This difference in p48 phosphorylation was also observed with cGMP-dependent protein kinase purified from ata A3 mutant cells.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7796456

  18. Modulation of penetrance by the wild-type allele in dominantly inherited erythropoietic protoporphyria and acute hepatic porphyrias.

    PubMed

    Gouya, Laurent; Puy, Hervé; Robreau, Anne-Marie; Lyoumi, Said; Lamoril, Jérome; Da Silva, Vasco; Grandchamp, Bernard; Deybach, Jean-Charles

    2004-02-01

    We have recently demonstrated that in an autosomal dominant porphyria, erythropoietic protoporphyria (EPP), the coinheritance of a ferrochelatase (FECH) gene defect and of a wild-type low-expressed FECH allele is generally involved in the clinical expression of EPP. This mechanism may provide a model for phenotype modulation by minor variations in the expression of the wild-type allele in the other three autosomal dominant porphyrias that exhibit incomplete penetrance: acute intermittent porphyria (AIP), variegata porphyria (VP) and hereditary coproporphyria (HC), which are caused by partial deficiencies of hydroxy-methyl bilane synthase (HMBS), protoporphyrinogen oxidase (PPOX) and coproporphyrinogen oxidase (CPO), respectively. Given the dominant mode of inheritance of EPP, VP, AIP and HC, we first confirmed that the 200 overtly porphyric subjects (55 EPP, 58 AIP, 56 VP; 31 HC) presented a single mutation restricted to one allele (20 novel mutations and 162 known mutations). We then analysed the available single-nucleotide polymorphisms (SNPs) present at high frequencies in the general population and spreading throughout the FECH, HMBS, PPOX and the CPO genes in four case-control association studies. Finally, we explored the functional consequences of polymorphisms on the abundance of wild-type RNA, and used relative allelic mRNA determinations to find out whether low-expressed HMBS, PPOX and the CPO alleles occur in the general population. We confirm that the wild-type low-expressed allele phenomenon is usually operative in the mechanism of variable penetrance in EPP, but conclude that this is not the case in AIP and VP. For HC, the CPO mRNA determinations strongly suggest that normal CPO alleles with low-expression are present, but whether this low-expression of the wild-type allele could modulate the penetrance of a CPO gene defect in HC families remains to be ascertained. PMID:14669009

  19. Assessing benzene-induced toxicity on wild type Euglena gracilis Z and its mutant strain SMZ.

    PubMed

    Peng, Cheng; Arthur, Dionne M; Sichani, Homa Teimouri; Xia, Qing; Ng, Jack C

    2013-11-01

    Benzene is a representative member of volatile organic compounds and has been widely used as an industrial solvent. Groundwater contamination of benzene may pose risks to human health and ecosystems. Detection of benzene in the groundwater using chemical analysis is expensive and time consuming. In addition, biological responses to environmental exposures are uninformative using such analysis. Therefore, the aim of this study was to employ a microorganism, Euglena gracilis (E. gracilis) as a putative model to monitor the contamination of benzene in groundwater. To this end, we examined the wild type of E. gracilis Z and its mutant form, SMZ in their growth rate, morphology, chlorophyll content, formation of reactive oxygen species (ROS) and DNA damage in response to benzene exposure. The results showed that benzene inhibited cell growth in a dose response manner up to 48 h of exposure. SMZ showed a greater sensitivity compared to Z in response to benzene exposure. The difference was more evident at lower concentrations of benzene (0.005-5 μM) where growth inhibition occurred in SMZ but not in Z cells. We found that benzene induced morphological changes, formation of lipofuscin, and decreased chlorophyll content in Z strain in a dose response manner. No significant differences were found between the two strains in ROS formation and DNA damage by benzene at concentrations affecting cell growth. Based on these results, we conclude that E. gracilis cells were sensitive to benzene-induced toxicities for certain endpoints such as cell growth rate, morphological change, depletion of chlorophyll. Therefore, it is a potentially suitable model for monitoring the contamination of benzene and its effects in the groundwater. PMID:24034892

  20. Cytidine is a novel substrate for wild-type concentrative nucleoside transporter 2.

    PubMed

    Nagai, Katsuhito; Nagasawa, Kazuki; Koma, Mineto; Hotta, Ayumi; Fujimoto, Sadaki

    2006-08-25

    Nucleoside transporter (NT) plays key roles in the physiology of nucleosides and the pharmacology of its analogues in mammals. We previously cloned Na+/nucleoside cotransporter CNT2 from mouse M5076 ovarian sarcoma cells, the peptide encoded by it differing from that by the previously reported mouse CNT2 in five substitutions, and observed that the transporter can take up cytidine, like CNT1 and CNT3. In the present study, we examined which of the two aforementioned CNT2 is the normal one, and whether or not cytidine is transported via the previously reported CNT2. The peptide encoded by CNT2 derived from mouse intestine, liver, spleen, and ovary was identical to that previously reported. The uptake of [3H]cytidine, but not [3H]thymidine, by Cos-7 cells transfected with CNT2 cDNA obtained from mouse intestine was much greater than that by mock cells, as in the case of [3H]uridine, a typical substrate of NT. [3H]Cytidine and [3H]uridine were taken up via CNT2, in temperature-, extracellular Na+-, and substrate concentration-dependent manners. The uptake of [3H]cytidine and [3H]uridine mediated by CNT2 was significantly inhibited by the variety of nucleosides used in this study, except for thymidine, and inhibition of the [3H]uridine uptake by cytidine was competitive. The [3H]uridine uptake via CNT2 was significantly decreased by the addition of cytarabin or gemcitabine, antimetabolites of cytidine analogue. These results indicated that the previously reported mouse CNT2 is the wild-type one, and cytidine is transported mediated by the same recognition site on the CNT2 with uridine, and furthermore, cytidine analogues may be substrates for the transporter. PMID:16828706

  1. Direct conversion of xylan to butanol by a wild-type Clostridium species strain G117.

    PubMed

    Yan, Yu; Basu, Anindya; Li, Tinggang; He, Jianzhong

    2016-08-01

    Lignocellulosic biomass has great potential for use as a carbon source for the production of second-generation biofuels by solventogenic bacteria. Here we describe the production of butanol by a newly discovered wild-type Clostridium species strain G117 with xylan as the sole carbon source for fermentation. Strain G117 produced 0.86 ± 0.07 g/L butanol and 53.4 ± 0.05 mL hydrogen directly from 60 g/L xylan provided that had undergone no prior enzymatic hydrolysis. After process optimization, the amount of butanol produced from xylan was increased to 1.24 ± 0.37 g/L. In contrast to traditional acetone-butanol-ethanol (ABE) solventogenic fermentation, xylan supported fermentation in strain G117 and negligible amount of acetone was produced. The expression of genes normally associated with acetone production (adc and ctfB2) were down-regulated compared to xylose fed cultures. This lack of acetone production may greatly simplify downstream separation process. Moreover, higher amount of butanol (2.94 g/L) was produced from 16.99 g/L xylo-oligosaccharides, suggesting a major role for strain G117 in butanol production from xylan and its oligosaccharides. The unique ability of strain G117 to produce a considerable amount of butanol directly from xylan without producing undesirable fermentation byproducts opens the door to the possibility of cost-effective biofuels production in a single step. Biotechnol. Bioeng. 2016;113: 1702-1710. © 2016 Wiley Periodicals, Inc. PMID:26803924

  2. Wild-type p53 and p73 negatively regulate expression of proliferation related genes.

    PubMed

    Scian, M J; Carchman, E H; Mohanraj, L; Stagliano, K E R; Anderson, M A E; Deb, D; Crane, B M; Kiyono, T; Windle, B; Deb, S P; Deb, S

    2008-04-17

    When normal cells come under stress, the wild-type (WT) p53 level increases resulting in the regulation of gene expression responsible for growth arrest or apoptosis. Here we show that elevated levels of WT p53 or its homologue, p73, inhibit expression of a number of cell cycle regulatory and growth promoting genes. Our analysis also identified a group of genes whose expression is differentially regulated by WT p53 and p73. We have infected p53-null H1299 human lung carcinoma cells with recombinant adenoviruses expressing WT p53, p73 or beta-galactosidase, and have undertaken microarray hybridization analyses to identify genes whose expression profile is altered by p53 or p73. Quantitative real-time PCR verified the repression of E2F-5, centromere protein A and E, minichromosome maintenance proteins (MCM)-2, -3, -5, -6 and -7 and human CDC25B after p53 expression. 5-Fluorouracil treatment of colon carcinoma HCT116 cells expressing WT p53 results in a reduction of the cyclin B2 protein level suggesting that DNA damage may indeed cause repression of these genes. Transient transcriptional assays verified that WT p53 repressed promoters of a number of these genes. Interestingly, a gain-of-function p53 mutant instead upregulated a number of these promoters in transient transfection. Using promoter deletion mutants of MCM-7 we have found that WT p53-mediated repression needs a minimal promoter that contains a single E2F site and surrounding sequences. However, a single E2F site cannot be significantly repressed by WT p53. Many of the genes identified are also repressed by p21. Thus, our work shows that WT p53 and p73 repress a number of growth-related genes and that in many instances this repression may be through the induction of p21. PMID:17982488

  3. MicroRNA-based Therapeutic Strategies for Targeting Mutant and Wild Type RAS in Cancer

    PubMed Central

    Sharma, Sriganesh B.; Ruppert, J. Michael

    2015-01-01

    MicroRNAs (miRs) have been causally implicated in the progression and development of a wide variety of cancers. miRs modulate the activity of key cell signaling networks by regulating the translation of pathway component proteins. Thus, the pharmacological targeting of miRs that regulate cancer cell signaling networks, either by promoting (using miR-supplementation) or by suppressing (using anti-sense oligonucleotide based strategies) miR activity is an area of intense research. The RAS-Extracellular signal regulated kinase (ERK) pathway represents a major miR-regulated signaling network that endows cells with some of the classical hallmarks of cancer, and is often inappropriately activated in malignancies by somatic genetic alteration through point mutation or alteration of gene copy number. In addition, recent progress indicates that many tumors may be deficient in GTPase activating proteins (GAPs) due to the collaborative action of oncogenic microRNAs. Recent studies also suggest that in tumors harboring a mutant RAS allele there is a critical role for wild type RAS proteins in determining overall RAS-ERK pathway activity. Together, these two advances comprise a new opportunity for therapeutic intervention. In this review, we evaluate miR-based therapeutic strategies for modulating RAS-ERK signaling in cancers, in particular for more direct modulation of RAS-GTP levels, with the potential to complement current strategies in order to yield more durable treatment responses. To this end, we discuss the potential for miR-based therapies focused on three prominent miRs including the pan-RAS regulator let-7 and the GAP regulator comprised of miR-206 and miR-21 (miR-206/21). PMID:26284568

  4. Genistein potentiates wild-type and delta F508-CFTR channel activity.

    PubMed

    Hwang, T C; Wang, F; Yang, I C; Reenstra, W W

    1997-09-01

    Effects of genistein on wild-type (wt) and delta F508-cystic fibrosis transmembrane conductance regulator (CFTR) were studied in NIH/3T3 cells stably transfected with wt or mutant CFTR cDNA. As measured by I- efflux, half-maximal concentration of agonist (K1/2) for forskolin-dependent activation was greater for delta F508-CFTR than wt-CFTR. Genistein decreased the K1/2 for both forms of the channel and increased the maximal activity of delta F508-CFTR by 3.7-fold. In cell-attached patches, 10 microM forskolin induced minimal delta F508-CFTR activity with characteristic prolonged closed times (estimated time constant, > 30 s). Genistein increased the forskolin-induced macroscopic currents of wt-CFTR and delta F508-CFTR by 3- and 19-fold, respectively. Variance analysis suggested that in the presence of forskolin and genistein the open probabilities (Po) of wt- and delta F508-CFTR were identical. In single-channel studies, at maximal adenosine 3',5'-cyclic monophosphate (cAMP) stimulation, genistein increased the Po of wt-CFTR by prolonging the open time, but, at submaximal cAMP stimulation, the Po was increased by prolonging the open time and shortening the closed time. In excised patches with CFTR channels preactivated in the cell-attached mode, genistein increased ATP-dependent wt- and delta F508-CFTR current about twofold by prolonging the open time. Our results thus suggest that phosphorylation-dependent activation of delta F508-CFTR is defective and that genistein corrects this defect at least in part by binding to the CFTR protein. PMID:9316420

  5. Human IL-2 mutein with higher antitumor efficacy than wild type IL-2.

    PubMed

    Carmenate, Tania; Pacios, Anabel; Enamorado, Michel; Moreno, Ernesto; Garcia-Martínez, Karina; Fuente, Dasha; León, Kalet

    2013-06-15

    IL-2 has been used for the treatment of melanoma and renal cell carcinoma, but this therapy has limited efficacy and severe toxicity. Currently, it is assumed that part of the limited efficacy is due to the IL-2-driven preferential expansion of regulatory T cells, which dampen the antitumor immunity. In this study, we characterize a human IL-2 mutant with higher antitumor efficacy and lower toxicity than wild type human IL-2 (wtIL-2). The mutant differs from wtIL-2 by four mutations at the interface with the α subunit of IL-2R. The IL-2 mutant induces in vitro proliferation of CD8(+)CD44(hi) and NK1.1 cells as efficiently as does wtIL-2, but it shows a reduced capacity to induce proliferation of CD4(+)Foxp3(+) regulatory T cells. The IL-2 mutant shows a higher antimetastatic effect than does wtIL-2 in several transplantable tumor models: the experimental metastasis model of MB16F0 melanoma and the experimental and spontaneous metastasis models for the mouse pulmonary carcinoma 3LL-D1222. Relevantly, the IL-2 mutant also exhibits lower lung and liver toxicity than does wtIL-2 when used at high doses in mice. In silico simulations, using a calibrated mathematical model, predict that the properties of IL-2 mutein are a consequence of the reduction, of at least two orders of magnitude, in its affinity for the α subunit of IL-2R (CD25). The human IL-2 mutant described in the present work could be a good candidate for improving cancer therapy based on IL-2. PMID:23677467

  6. Primary charge separation within P870* in wild type and heterodimer mutants in femtosecond time domain.

    PubMed

    Khatypov, R A; Khmelnitskiy, A Yu; Khristin, A M; Fufina, T Yu; Vasilieva, L G; Shuvalov, V A

    2012-08-01

    Primary charge separation dynamics in the reaction center (RC) of purple bacterium Rhodobacter sphaeroides and its P870 heterodimer mutants have been studied using femtosecond time-resolved spectroscopy with 20 and 40fs excitation at 870nm at 293K. Absorbance increase in the 1060-1130nm region that is presumably attributed to P(A)(δ+) cation radical molecule as a part of mixed state with a charge transfer character P*(P(A)(δ+)P(B)(δ-)) was found. This state appears at 120-180fs time delay in the wild type RC and even faster in H(L173)L and H(M202)L heterodimer mutants and precedes electron transfer (ET) to B(A) bacteriochlorophyll with absorption band at 1020nm in WT. The formation of the P(A)(δ+)B(A)(δ-) state is a result of the electron transfer from P*(P(A)(δ+)P(B)(δ-)) to the primary electron acceptor B(A) (still mixed with P*) with the apparent time delay of ~1.1ps. Next step of ET is accompanied by the 3-ps appearance of bacteriopheophytin a(-) (H(A)(-)) band at 960nm. The study of the wave packet formation upon 20-fs illumination has shown that the vibration energy of the wave packet promotes reversible overcoming of an energy barrier between two potential energy surfaces P* and P*(P(A)(δ+)B(A)(δ-)) at ~500fs. For longer excitation pulses (40fs) this promotion is absent and tunneling through an energy barrier takes about 3ps. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. PMID:22209778

  7. Profiling the RNA editomes of wild-type C. elegans and ADAR mutants.

    PubMed

    Zhao, Han-Qing; Zhang, Pan; Gao, Hua; He, Xiandong; Dou, Yanmei; Huang, August Y; Liu, Xi-Ming; Ye, Adam Y; Dong, Meng-Qiu; Wei, Liping

    2015-01-01

    RNA editing increases transcriptome diversity through post-transcriptional modifications of RNA. Adenosine deaminases that act on RNA (ADARs) catalyze the adenosine-to-inosine (A-to-I) conversion, the most common type of RNA editing in higher eukaryotes. Caenorhabditis elegans has two ADARs, ADR-1 and ADR-2, but their functions remain unclear. Here, we profiled the RNA editomes of C. elegans at different developmental stages of wild-type and ADAR mutants. We developed a new computational pipeline with a "bisulfite-seq-mapping-like" step and achieved a threefold increase in identification sensitivity. A total of 99.5% of the 47,660 A-to-I editing sites were found in clusters. Of the 3080 editing clusters, 65.7% overlapped with DNA transposons in noncoding regions and 73.7% could form hairpin structures. The numbers of editing sites and clusters were highest at the L1 and embryonic stages. The editing frequency of a cluster positively correlated with the number of editing sites within it. Intriguingly, for 80% of the clusters with 10 or more editing sites, almost all expressed transcripts were edited. Deletion of adr-1 reduced the editing frequency but not the number of editing clusters, whereas deletion of adr-2 nearly abolished RNA editing, indicating a modulating role of ADR-1 and an essential role of ADR-2 in A-to-I editing. Quantitative proteomics analysis showed that adr-2 mutant worms altered the abundance of proteins involved in aging and lifespan regulation. Consistent with this finding, we observed that worms lacking RNA editing were short-lived. Taken together, our results reveal a sophisticated landscape of RNA editing and distinct modes of action of different ADARs. PMID:25373143

  8. Targeting Mdmx to treat breast cancers with wild-type p53

    PubMed Central

    Haupt, S; Buckley, D; Pang, J-MB; Panimaya, J; Paul, P J; Gamell, C; Takano, E A; Ying Lee, Y; Hiddingh, S; Rogers, T-M; Teunisse, A F A S; Herold, M J; Marine, J-C; Fox, S B; Jochemsen, A; Haupt, Y

    2015-01-01

    The function of the tumor suppressor p53 is universally compromised in cancers. It is the most frequently mutated gene in human cancers (reviewed). In cases where p53 is not mutated, alternative regulatory pathways inactivate its tumor suppressive functions. This is primarily achieved through elevation in the expression of the key inhibitors of p53: Mdm2 or Mdmx (also called Mdm4) (reviewed). In breast cancer (BrCa), the frequency of p53 mutations varies markedly between the different subtypes, with basal-like BrCas bearing a high frequency of p53 mutations, whereas luminal BrCas generally express wild-type (wt) p53. Here we show that Mdmx is unexpectedly highly expressed in normal breast epithelial cells and its expression is further elevated in most luminal BrCas, whereas p53 expression is generally low, consistent with wt p53 status. Inducible knockdown (KD) of Mdmx in luminal BrCa MCF-7 cells impedes the growth of these cells in culture, in a p53-dependent manner. Importantly, KD of Mdmx in orthotopic xenograft transplants resulted in growth inhibition associated with prolonged survival, both in a preventative model and also in a treatment model. Growth impediment in response to Mdmx KD was associated with cellular senescence. The growth inhibitory capacity of Mdmx KD was recapitulated in an additional luminal BrCa cell line MPE600, which expresses wt p53. Further, the growth inhibitory capacity of Mdmx KD was also demonstrated in the wt p53 basal-like cell line SKBR7 line. These results identify Mdmx growth dependency in wt p53 expressing BrCas, across a range of subtypes. Based on our findings, we propose that Mdmx targeting is an attractive strategy for treating BrCas harboring wt p53. PMID:26181202

  9. Manganese supplementation protects against diet-induced diabetes in wild type mice by enhancing insulin secretion.

    PubMed

    Lee, Soh-Hyun; Jouihan, Hani A; Cooksey, Robert C; Jones, Deborah; Kim, Hyung J; Winge, Dennis R; McClain, Donald A

    2013-03-01

    Mitochondrial dysfunction is both a contributing mechanism and complication of diabetes, and oxidative stress contributes to that dysfunction. Mitochondrial manganese-superoxide dismutase (MnSOD) is a metalloenzyme that provides antioxidant protection. We have previously shown in a mouse model of hereditary iron overload that cytosolic iron levels affected mitochondrial manganese availability, MnSOD activity, and insulin secretion. We therefore sought to determine the metallation status of MnSOD in wild-type mice and whether altering that status affected β-cell function. 129/SvEVTac mice given supplemental manganese exhibited a 73% increase in hepatic MnSOD activity and increased metallation of MnSOD. To determine whether manganese supplementation offered glucose homeostasis under a situation of β-cell stress, we challenged C57BL/6J mice, which are more susceptible to diet-induced diabetes, with a high-fat diet for 12 weeks. Manganese was supplemented or not for the final 8 weeks on that diet, after which we examined glucose tolerance and the function of isolated islets. Liver mitochondria from manganese-injected C57BL/6J mice had similar increases in MnSOD activity (81%) and metallation as were seen in 129/SvEVTac mice. The manganese-treated group fed high fat had improved glucose tolerance (24% decrease in fasting glucose and 41% decrease in area under the glucose curve), comparable with mice on normal chow and increased serum insulin levels. Isolated islets from the manganese-treated group exhibited improved insulin secretion, decreased lipid peroxidation, and improved mitochondrial function. In conclusion, MnSOD metallation and activity can be augmented with manganese supplementation in normal mice on normal chow, and manganese treatment can increase insulin secretion to improve glucose tolerance under conditions of dietary stress. PMID:23372018

  10. Effects of chronic variable stress on cognition and Bace1 expression among wild-type mice.

    PubMed

    Cordner, Z A; Tamashiro, K L K

    2016-01-01

    Stressful life events, activation of the hypothalamic-pituitary-adrenal (HPA) axis and glucocorticoids are now thought to have a role in the development of several neurodegenerative and psychiatric disorders including Alzheimer's disease (AD) through mechanisms that may include exacerbation of cognitive impairment, neuronal loss, and beta-amyloid (Aβ) and tau neuropathology. In the current study, we use a wild-type mouse model to demonstrate that chronic variable stress impairs cognitive function and that aged mice are particularly susceptible. We also find that stress exposure is associated with a 1.5- to 2-fold increase in the expression of Bace1 in the hippocampus of young adult mice and the hippocampus, prefrontal cortex and amygdala of aged mice. Further, the increased expression of Bace1 was associated with decreased methylation of several CpGs in the Bace1 promoter region. In a second series of experiments, exposure to environmental enrichment (EE) prevented the stress-related changes in cognition, gene expression and DNA methylation. Together, these findings re-affirm the adverse effects of stress on cognition and further suggest that aged individuals are especially susceptible. In addition, demonstrating that chronic stress results in decreased DNA methylation and increased expression of Bace1 in the brain may provide a novel link between stress, Aβ pathology and AD. Finally, understanding the mechanisms by which EE prevented the effects of stress on cognition and Bace1 expression will be an important area of future study that may provide insights into novel approaches to the treatment of AD. PMID:27404286

  11. Internal binding sites for MSH: Analyses in wild-type and variant Cloudman melanoma cells

    SciTech Connect

    Orlow, S.J.; Hotchkiss, S.; Pawelek, J.M. )

    1990-01-01

    Cloudman S91 mouse melanoma cells express both external (plasma membrane) and internal binding sites for MSH. Using 125I-beta melanotropin (beta-MSH) as a probe, we report here an extensive series of studies on the biological relevance of these internal sites. Cells were swollen in a hypotonic buffer and lysed, and a particulate fraction was prepared by high-speed centrifugation. This fraction was incubated with 125I-beta-MSH with or without excess nonradioactive beta-MSH in the cold for 2 hours. The material was then layered onto a step-wise sucrose gradient and centrifuged; fractions were collected and counted in a gamma counter or assayed for various enzymatic activities. The following points were established: (1) Specific binding sites for MSH were observed sedimenting at an average density of 50% sucrose in amelanotic cells and at higher densities in melanotic cells. (2) These sites were similar in density to those observed when intact cells were labeled externally with 125I-beta-MSH and then warmed to promote internalization of the hormone. (3) Most of the internal binding sites were not as dense as fully melanized melanosomes. (4) In control experiments, the MSH binding sites were not found in cultured hepatoma cells. (5) Variant melanoma cells, which differed from the wild-type in their responses to MSH, had reduced expression of internal binding sites even though their ability to bind MSH to the outer cell surface appeared normal. (MSH-induced responses included changes in tyrosinase, dopa oxidase, and dopachrome conversion factor activities, melanization, proliferation, and morphology.) (6) Isobutylmethylxanthine, which enhanced cellular responsiveness to MSH, also enhanced expression of internal binding sites. The results indicate that expression of internal binding sites for MSH is an important criterion for cellular responsiveness to the hormone.

  12. Selective modulation of wild type receptor functions by mutants of G-protein-coupled receptors.

    PubMed

    Le Gouill, C; Parent, J L; Caron, C A; Gaudreau, R; Volkov, L; Rola-Pleszczynski, M; Stanková, J

    1999-04-30

    Members of the G-protein-coupled receptor (GPCR) family are involved in most aspects of higher eukaryote biology, and mutations in their coding sequence have been linked to several diseases. In the present study, we report that mutant GPCR can affect the functional properties of the co-expressed wild type (WT) receptor. Mutants of the human platelet-activating factor receptor that fail to show any detectable ligand binding (N285I and K298stop) or coupling to a G-protein (D63N, D289A, and Y293A) were co-expressed with the WT receptor in Chinese hamster ovary and COS-7 cells. In this context, N285I and K298stop mutant receptors inhibited 3H-WEB2086 binding and surface expression. Co-transfection with D63N resulted in a constitutively active receptor phenotype. Platelet-activating factor-induced inositol phosphate production in cells transfected with a 1:1 ratio of WT:D63N was higher than with the WT cDNA alone but was abolished with a 1:3 ratio. We confirmed that these findings could be extended to other GPCRs by showing that co-expression of the WT C-C chemokine receptor 2b with a carboxyl-terminal deletion mutant (K311stop), resulted in a decreased affinity and responsiveness to MCP-1. A better understanding of this phenomenon could lead to important tools for the prevention or treatment of certain diseases. PMID:10212233

  13. Subcellular localization of SREBP1 depends on its interaction with the C-terminal region of wild-type and disease related A-type lamins

    PubMed Central

    Duband-Goulet, Isabelle; Woerner, Stephanie; Gasparini, Sylvaine; Attanda, Wikayatou; Kondé, Emilie; Tellier-Lebègue, Carine; Craescu, Constantin T.; Gombault, Aurélie; Roussel, Pascal; Vadrot, Nathalie; Vicart, Patrick; Östlund, Cecilia; Worman, Howard J.; Zinn-Justin, Sophie; Buendia, Brigitte

    2011-01-01

    Lamins A and C are nuclear intermediate filament proteins expressed in most differentiated somatic cells. Previous data suggested that prelamin A, the lamin A precursor, accumulates in some lipodystrophy syndromes caused by mutations in the lamin A/C gene, and binds and inactivates the sterol regulatory element binding protein 1 (SREBP1). Here we show that, in vitro, the tail regions of prelamin A, lamin A and lamin C bind a polypeptide of SREBP1. Such interactions also occur in HeLa cells, since expression of lamin tail regions impedes nucleolar accumulation of the SREBP1 polypeptide fused to a nucleolar localization signal sequence. In addition, the tail regions of A-type lamin variants that occur in Dunnigan-type familial partial lipodystrophy of (R482W) and Hutchison Gilford progeria syndrome (Δ607–656) bind to the SREBP1 polypeptide in vitro, and the corresponding FLAG-tagged full-length lamin variants co-immunoprecipitate the SREBP1 polypeptide in cells. Overexpression of wild-type A-type lamins and variants favors SREBP1 polypeptide localization at the intranuclear periphery, suggesting its sequestration. Our data support the hypothesis that variation of A-type lamin protein level and spatial organization, in particular due to disease-linked mutations, influences the sequestration of SREBP1 at the nuclear envelope and thus contributes to the regulation of SREBP1 function. PMID:21993218

  14. Subcellular localization of SREBP1 depends on its interaction with the C-terminal region of wild-type and disease related A-type lamins

    SciTech Connect

    Duband-Goulet, Isabelle; Woerner, Stephanie; Gasparini, Sylvaine; Attanda, Wikayatou; Konde, Emilie; Tellier-Lebegue, Carine; Craescu, Constantin T.; Roussel, Pascal; Vadrot, Nathalie; Vicart, Patrick; Oestlund, Cecilia; Worman, Howard J.; and others

    2011-12-10

    Lamins A and C are nuclear intermediate filament proteins expressed in most differentiated somatic cells. Previous data suggested that prelamin A, the lamin A precursor, accumulates in some lipodystrophy syndromes caused by mutations in the lamin A/C gene, and binds and inactivates the sterol regulatory element binding protein 1 (SREBP1). Here we show that, in vitro, the tail regions of prelamin A, lamin A and lamin C bind a polypeptide of SREBP1. Such interactions also occur in HeLa cells, since expression of lamin tail regions impedes nucleolar accumulation of the SREBP1 polypeptide fused to a nucleolar localization signal sequence. In addition, the tail regions of A-type lamin variants that occur in Dunnigan-type familial partial lipodystrophy of (R482W) and Hutchison Gilford progeria syndrome ( Increment 607-656) bind to the SREBP1 polypeptide in vitro, and the corresponding FLAG-tagged full-length lamin variants co-immunoprecipitate the SREBP1 polypeptide in cells. Overexpression of wild-type A-type lamins and variants favors SREBP1 polypeptide localization at the intranuclear periphery, suggesting its sequestration. Our data support the hypothesis that variation of A-type lamin protein level and spatial organization, in particular due to disease-linked mutations, influences the sequestration of SREBP1 at the nuclear envelope and thus contributes to the regulation of SREBP1 function.

  15. Interaction of αA-crystallin F71L mutant with wild type αA- and αB-crystallins by mammalian two hybrid assay.

    PubMed

    Ramkumar, Srinivasagan; Thankappan, Bency; Fujii, Noriko; Natarajaseenivasan, Kalimuthusamy; Anbarasu, Kumarasamy

    2015-05-01

    Incidence of age related cataract (ARC) increases by a variety of factors including metabolic and environmental factors. Nonetheless, genetic mutations are responsible for the altered structural stability of the proteins, especially; the F71L mutation in αA-crystallin has been shown to be responsible for the incidence of cataracts. However, structural characteristics and chaperone function of this mutant and its interaction with wild type (WT) crystallins may aid to decipher its role in cataractogenesis. The aim of the present study is to show the interaction of F71L mutant protein with the WT α-crystallins. The F71L mutant used in this study was created by site-directed mutagenesis, overexpressed and purified. Biophysical characteristics determined by size exclusion HPLC, DLS, CD spectrometry, tryptophan fluorescence and surface hydrophobicity did not show significant structural changes in the mutant protein compared to WT counterpart. Interestingly, the F71L mutant displayed a significant loss in homogenous interaction with WT αA-crystallin and F71L mutant as well as heterogeneous interaction with αB-crystallin as evaluated by mammalian two hybrid system. Our findings suggest that F71L loses the ability to form homo and hetero-oligomers seems to result in the loss in chaperone like activity (CLA) and refractive index resulting in the development of cataracts. PMID:25720831

  16. Increased expression of SIRT2 is a novel marker of cellular senescence and is dependent on wild type p53 status.

    PubMed

    Anwar, Tarique; Khosla, Sanjeev; Ramakrishna, Gayatri

    2016-07-17

    Sirtuins (SIRT) belonging to the NAD+ dependent histone deacetylase III class of enzymes have emerged as master regulators of metabolism and longevity. However, their role in prevention of organismal aging and cellular senescence still remains controversial. In the present study, we now report upregulation of SIRT2 as a specific feature associated with stress induced premature senescence but not with either quiescence or cell death. Additionally, increase in SIRT2 expression was noted in different types of senescent conditions such as replicative and oncogene induced senescence using multiple cell lines. Induction of SIRT2 expression during senescence was dependent on p53 status as depletion of p53 by shRNA prevented its accumulation. Chromatin immunoprecipitation revealed the presence of p53 binding sites on the SIRT2 promoter suggesting its regulation by p53, which was also corroborated by the SEAP reporter assay. Overexpression or knockdown of SIRT2 had no effect on stress induced premature senescence, thereby indicating that SIRT2 increase is not a cause of senescence; rather it is an effect linked to senescence-associated changes. Overall, our results suggest SIRT2 as a promising marker of cellular senescence at least in cells with wild type p53 status. PMID:27229617

  17. Nitric oxide-induced p53 accumulation and regulation of inducible nitric oxide synthase expression by wild-type p53.

    PubMed Central

    Forrester, K; Ambs, S; Lupold, S E; Kapust, R B; Spillare, E A; Weinberg, W C; Felley-Bosco, E; Wang, X W; Geller, D A; Tzeng, E; Billiar, T R; Harris, C C

    1996-01-01

    The tumor suppressor gene product p53 plays an important role in the cellular response to DNA damage from exogenous chemical and physical mutagens. Therefore, we hypothesized that p53 performs a similar role in response to putative endogenous mutagens, such as nitric oxide (NO). We report here that exposure of human cells to NO generated from an NO donor or from overexpression of inducible nitric oxide synthase (NOS2) results in p53 protein accumulation. In addition, expression of wild-type (WT) p53 in a variety of human tumor cell lines, as well as murine fibroblasts, results in down-regulation of NOS2 expression through inhibition of the NOS2 promoter. These data are consistent with the hypothesis of a negative feedback loop in which endogenous NO-induced DNA damage results in WT p53 accumulation and provides a novel mechanism by which p53 safeguards against DNA damage through p53-mediated transrepression of NOS2 gene expression, thus reducing the potential for NO-induced DNA damage. Images Fig. 1 Fig. 2 Fig. 3 PMID:8637893

  18. Reactivating p53 functions by suppressing its novel inhibitor iASPP: a potential therapeutic opportunity in p53 wild-type tumors

    PubMed Central

    Dong, Peixin; Ihira, Kei; Hamada, Junichi; Watari, Hidemichi; Yamada, Takahiro; Hosaka, Masayoshi; Hanley, Sharon J.B.; Kudo, Masataka; Sakuragi, Noriaki

    2015-01-01

    Although mutational inactivation of p53 is found in 50% of all human tumors, a subset of tumors display defective p53 function, but retain wild-type (WT) p53. Here, direct and indirect mechanisms leading to the loss of WT p53 activities are discussed. We summarize the oncogenic roles of iASPP, an inhibitor of WT p53, in promoting proliferation, invasion, drug or radiation-resistance and metastasis. From the therapeutic view, we highlight promising perspectives of microRNA-124, peptide and small molecules that reduce or block iASPP for the treatment of cancer. High iASPP expression enhances proliferation, aggressive behavior, the resistance to radiation/chemotherapy and correlates with poor prognosis in a range of human tumors. Overexpression of iASPP accelerates tumorigenesis and invasion through p53-dependent and p53-independent mechanisms. MicroRNA-124 directly targets iASPP and represses the growth and invasiveness of cancer cells. The disruption of iASPP-p53 interaction by a p53-derived peptide A34 restores p53 function in cancer cells. The inhibition of iASPP phosphorylation with small molecules induces p53-dependent apoptosis and growth suppression. The mechanisms underlying aberrant expression of iASPP in human tumors should be further investigated. Reactivating WT p53 functions by targeting its novel inhibitor iASPP holds promise for potential therapeutic interventions in the treatment of WT p53-containing tumors. PMID:26343523

  19. Human wild-type tau interacts with wingless pathway components and produces neurofibrillary pathology in Drosophila.

    PubMed

    Jackson, George R; Wiedau-Pazos, Martina; Sang, Tzu-Kang; Wagle, Naveed; Brown, Carlos A; Massachi, Sasan; Geschwind, Daniel H

    2002-05-16

    Pathologic alterations in the microtubule-associated protein tau have been implicated in a number of neurodegenerative disorders, including Alzheimer's disease (AD), progressive supranuclear palsy (PSP), and frontotemporal dementia (FTD). Here, we show that tau overexpression, in combination with phosphorylation by the Drosophila glycogen synthase kinase-3 (GSK-3) homolog and wingless pathway component (Shaggy), exacerbated neurodegeneration induced by tau overexpression alone, leading to neurofibrillary pathology in the fly. Furthermore, manipulation of other wingless signaling molecules downstream from shaggy demonstrated that components of the Wnt signaling pathway modulate neurodegeneration induced by tau pathology in vivo but suggested that tau phosphorylation by GSK-3beta differs from canonical Wnt effects on beta-catenin stability and TCF activity. The genetic system we have established provides a powerful reagent for identification of novel modifiers of tau-induced neurodegeneration that may serve as future therapeutic targets. PMID:12062036

  20. Regulation of feeding behavior and food intake by appetite-regulating peptides in wild-type and growth hormone-transgenic coho salmon.

    PubMed

    White, Samantha L; Volkoff, Helene; Devlin, Robert H

    2016-08-01

    Survival, competition, growth and reproductive success in fishes are highly dependent on food intake, food availability and feeding behavior and are all influenced by a complex set of metabolic and neuroendocrine mechanisms. Overexpression of growth hormone (GH) in transgenic fish can result in greatly enhanced growth rates, feed conversion, feeding motivation and food intake. The objectives of this study were to compare seasonal feeding behavior of non-transgenic wild-type (NT) and GH-transgenic (T) coho salmon (Oncorhynchus kisutch), and to examine the effects of intraperitoneal injections of the appetite-regulating peptides cholecystokinin (CCK-8), bombesin (BBS), glucagon-like peptide-1 (GLP-1), and alpha-melanocyte-stimulating hormone (α-MSH) on feeding behavior. T salmon fed consistently across all seasons, whereas NT dramatically reduced their food intake in winter, indicating the seasonal regulation of appetite can be altered by overexpression of GH in T fish. Intraperitoneal injections of CCK-8 and BBS caused a significant and rapid decrease in food intake for both genotypes. Treatment with either GLP-1 or α-MSH resulted in a significant suppression of food intake for NT but had no effect in T coho salmon. The differential response of T and NT fish to α-MSH is consistent with the melanocortin-4 receptor system being a significant pathway by which GH acts to stimulate appetite. Taken together, these results suggest that chronically increased levels of GH alter feeding regulatory pathways to different extents for individual peptides, and that altered feeding behavior in transgenic coho salmon may arise, in part, from changes in sensitivity to peripheral appetite-regulating signals. PMID:27149948

  1. Optimization of glutathione production in batch and fed-batch cultures by the wild-type and recombinant strains of the methylotrophic yeast Hansenula polymorpha DL-1

    PubMed Central

    2011-01-01

    Background Tripeptide glutathione (gamma-glutamyl-L-cysteinyl-glycine) is the most abundant non-protein thiol that protects cells from metabolic and oxidative stresses and is widely used as medicine, food additives and in cosmetic industry. The methylotrophic yeast Hansenula polymorpha is regarded as a rich source of glutathione due to the role of this thiol in detoxifications of key intermediates of methanol metabolism. Cellular and extracellular glutathione production of H. polymorpha DL-1 in the wild type and recombinant strains which overexpress genes of glutathione biosynthesis (GSH2) and its precursor cysteine (MET4) was studied. Results Glutathione producing capacity of H. polymorpha DL-1 depending on parameters of cultivation (dissolved oxygen tension, pH, stirrer speed), carbon substrate (glucose, methanol) and type of overexpressed genes of glutathione and its precursor biosynthesis during batch and fed-batch fermentations were studied. Under optimized conditions of glucose fed-batch cultivation, the glutathione productivity of the engineered strains was increased from ~900 up to ~ 2300 mg of Total Intracellular Glutathione (TIG) or GSH+GSSGin, per liter of culture medium. Meantime, methanol fed-batch cultivation of one of the recombinant strains allowed achieving the extracellular glutathione productivity up to 250 mg of Total Extracellular Glutathione (TEG) or GSH+GSSGex, per liter of the culture medium. Conclusions H. polymorpha is an competitive glutathione producer as compared to other known yeast and bacteria strains (Saccharomyces cerevisiae, Candida utilis, Escherichia coli, Lactococcus lactis etc.) with good perspectives for further improvement especially for production of extracellular form of glutathione. PMID:21255454

  2. Hypoxia-induced lncRNA-NUTF2P3-001 contributes to tumorigenesis of pancreatic cancer by derepressing the miR-3923/KRAS pathway.

    PubMed

    Li, Xiang; Deng, Shi-jiang; Zhu, Shuai; Jin, Yan; Cui, Shi-peng; Chen, Jing-yuan; Xiang, Cheng; Li, Qun-ying; He, Chi; Zhao, Shu-feng; Chen, Heng-yu; Niu, Yi; Liu, Yang; Deng, Shi-chang; Wang, Chun-you; Zhao, Gang

    2016-02-01

    Recent studies indicate that long non-coding RNAs (lncRNAs) play crucial roles in numerous cancers, while their function in pancreatic cancer is rarely elucidated. The present study identifies a functional lncRNA and its potential role in tumorigenesis of pancreatic cancer. Microarray co-assay for lncRNAs and mRNAs demonstrates that lncRNA-NUTF2P3-001 is remarkably overexpressed in pancreatic cancer and chronic pancreatitis tissues, which positively correlates with KRAS mRNA expression. After downregulating lncRNA-NUTF2P3-001, the proliferation and invasion of pancreatic cancer cell are significantly inhibited both in vitro and vivo, accompanying with decreased KRAS expression. The dual-luciferase reporter assay further validates that lncRNA-NUTF2P3-001 and 3'UTR of KRAS mRNA competitively bind with miR-3923. Furthermore, miR-3923 overexpression simulates the inhibiting effects of lncRNA-NUTF2P3-001-siRNA on pancreatic cancer cell, which is rescued by miR-3923 inhibitor. Specifically, the present study further reveals that lncRNA-NUTF2P3-001 is upregulated in pancreatic cancer cells under hypoxia and CoCl2 treatment, which is attributed to the binding of hypoxia-inducible factor-1α (HIF-1α) to hypoxia response elements (HREs) in the upstream of KRAS promoter. Data from pancreatic cancer patients show a positive correlation between lncRNA-NUTF2P3-001 and KRAS, which is associated with advanced tumor stage and worse prognosis. Hence, our data provide a new lncRNA-mediated regulatory mechanism for the tumor oncogene KRAS and implicate that lncRNA-NUTF2P3-001 and miR-3923 can be applied as novel predictors and therapeutic targets for pancreatic cancer. PMID:26755660

  3. MicroRNA-31 initiates lung tumorigenesis and promotes mutant KRAS-driven lung cancer

    PubMed Central

    Edmonds, Mick D.; Boyd, Kelli L.; Moyo, Tamara; Mitra, Ramkrishna; Duszynski, Robert; Arrate, Maria Pia; Chen, Xi; Zhao, Zhongming; Blackwell, Timothy S.; Andl, Thomas; Eischen, Christine M.

    2015-01-01

    MicroRNA (miR) are important regulators of gene expression, and aberrant miR expression has been linked to oncogenesis; however, little is understood about their contribution to lung tumorigenesis. Here, we determined that miR-31 is overexpressed in human lung adenocarcinoma and this overexpression independently correlates with decreased patient survival. We developed a transgenic mouse model that allows for lung-specific expression of miR-31 to test the oncogenic potential of miR-31 in the lung. Using this model, we observed that miR-31 induction results in lung hyperplasia, followed by adenoma formation and later adenocarcinoma development. Moreover, induced expression of miR-31 in mice cooperated with mutant KRAS to accelerate lung tumorigenesis. We determined that miR-31 regulates lung epithelial cell growth and identified 6 negative regulators of RAS/MAPK signaling as direct targets of miR-31. Our study distinguishes miR-31 as a driver of lung tumorigenesis that promotes mutant KRAS-mediated oncogenesis and reveals that miR-31 directly targets and reduces expression of negative regulators of RAS/MAPK signaling. PMID:26657862

  4. [Overexpression of FKS1 to improve yeast autolysis-stress].

    PubMed

    Li, Jia; Wang, Jinjing; Li, Qi

    2015-09-01

    With the development of high gravity brewing, yeast cells are exposed to multiple brewing-associated stresses, such as increased osmotic pressure, enhanced alcohol concentration and nutritional imbalance. These will speed up yeast autolysis, which seriously influence beer flavor and quality. To increase yeast anti-autolytic ability, FKS1 overexpression strain was constructed by 18S rDNA. The concentration of β-1,3-glucan of overexpression strain was 62% higher than that of wild type strain. Meantime, FKS1 overexpression strain increased anti-stress ability at 8% ethanol, 0.4 mol/L NaCl and starvation stress. Under simulated autolysis, FKS1 showed good anti-autolytic ability by slower autolysis. These results confirms the potential of FKS1 overexpression to tackle yeast autolysis in high-gravity brewing. PMID:26955712

  5. Novel approach to abuse the hyperactive K-Ras pathway for adenoviral gene therapy of colorectal cancer

    SciTech Connect

    Naumov, Inna; Kazanov, Dina; Lisiansky, Victoria; Starr, Alex; Aroch, Ilan; Shapira, Shiran; Kraus, Sarah; Arber, Nadir

    2012-01-15

    Background: Functional activation of oncogenic K-Ras signaling pathway plays an important role in the early events of colorectal carcinogenesis (CRC). K-Ras proto-oncogene is involved in 35-40% of CRC cases. Mutations in the Ras gene trigger the transduction of proliferative and anti-apoptotic signals, even in the absence of extra cellular stimuli. The objective of the current study was to use a gene-targeting approach to kill human CRC cells selectively harboring mutated K-Ras. Results: A recombinant adenovirus that carries a lethal gene, PUMA, under the control of a Ras responsive promoter (Ad-Py4-SV40-PUMA) was used selectively to target CRC cells (HCT116, SW480, DLD1 and RIE-Ras) that possess a hyperactive Ras pathway while using HT29 and RIE cells as a control that harbors wild type Ras and exhibit very low Ras activity. Control vector, without the Ras responsive promoter elements was used to assess the specificity of our 'gene therapy' approach. Both adenoviral vectors were assed in vitro and in xenograft model in vivo. Ad-Py4-SV40-PUMA showed high potency to induce {approx} 50% apoptosis in vitro, to abolish completely tumor formation by infecting cells with the Ad-Py4-SV40-PUMA prior xenografting them in nude mice and high ability to suppress by {approx} 35% tumor progression in vivo in already established tumors. Conclusions: Selective targeting of CRC cells with the activated Ras pathway may be a novel and effective therapy in CRC. The high potency of this adenoviral vector may help to overcome an undetectable micro metastasis that is the major hurdle in challenging with CRC.

  6. Validation of a Multiplex Allele-Specific Polymerase Chain Reaction Assay for Detection of KRAS Gene Mutations in Formalin-Fixed, Paraffin-Embedded Tissues from Colorectal Cancer Patients

    PubMed Central

    Seekhuntod, Sirirat; Thavarungkul, Paninee; Chaichanawongsaroj, Nuntaree

    2016-01-01

    Background Patients with KRAS mutations do not respond to epidermal growth factor receptor (EGFR) inhibitors and fail to benefit from adjuvant chemotherapy. Mutation analysis of KRAS is needed before starting treatment with monoclonal anti-EGFR antibodies in patients with metastatic colorectal cancer (mCRC). The objective of this study is to develop a multiplex allele-specific PCR (MAS-PCR) assay to detect KRAS mutations. Methods We developed a single-tube MAS-PCR assay for the detection of seven KRAS mutations (G12D, G12A, G12R, G12C, G12S, G12V, and G13D). We performed MAS-PCR assay analysis for KRAS on DNA isolated from 270 formalin-fixed paraffin-embedded (FFPE) colorectal cancer tissues. Sequences of all 270 samples were determined by pyrosequencing. Seven known point-mutation DNA samples diluted with wild-type DNA were assayed to determine the limitation of detection and reproducibility of the MAS-PCR assay. Results Overall, the results of MAS-PCR assay were in good concordance with pyrosequencing, and only seven discordant samples were found. The MAS-PCR assay reproducibly detected 1 to 2% mutant alleles. The most common mutations were G13D in codon 13 (49.17%), G12D (25.83%) and G12V (12.50%) in codon 12. Conclusion The MAS-PCR assay provides a rapid, cost-effective, and reliable diagnostic tool for accurate detection of KRAS mutations in routine FFPE colorectal cancer tissues. PMID:26812617

  7. Fertility comparison between wild type and transgenic mice by in vitro fertilization

    PubMed Central

    Vasudevan, Kuzhalini; Raber, James

    2011-01-01

    . Oocytes from superovulated females were inseminated with sperm of same background. Fertility rate was considered as the percentage of two cell embryos scored 24 h after insemination. The data collected from this study shows that the fertilization rate is affected (reduced to half fold) in some of the transgenic mice compared to the respective Wild Type (WT) mice. For the WT the average fertility rate ranged from 80% (C57BL/6), 90% (FVB/N), 45% (129Sv/J × C57Bl/6)F1 and 43% (CD1). For transgenic mice it was 52% (C57BL/6), 65% (FVB/N), 22% (129Sv/J × C57Bl/6)F1 and 25% (CD1). PMID:19844803

  8. PHEX Mimetic (SPR4-Peptide) Corrects and Improves HYP and Wild Type Mice Energy-Metabolism

    PubMed Central

    Zelenchuk, Lesya V.; Hedge, Anne-Marie; Rowe, Peter S. N.

    2014-01-01

    Context PHEX or DMP1 mutations cause hypophosphatemic-rickets and altered energy metabolism. PHEX binds to DMP1-ASARM-motif to form a complex with α5β3 integrin that suppresses FGF23 expression. ASARM-peptides increase FGF23 by disrupting the PHEX-DMP1-Integrin complex. We used a 4.2 kDa peptide (SPR4) that binds to ASARM-peptide/motif to study the DMP1-PHEX interaction and to assess SPR4 for the treatment of energy metabolism defects in HYP and potentially other bone-mineral disorders. Design Subcutaneously transplanted osmotic pumps were used to infuse SPR4-peptide or vehicle (VE) into wild-type mice (WT) and HYP-mice (PHEX mutation) for 4 weeks. Results SPR4 partially corrected HYP mice hypophosphatemia and increased serum 1.25(OH)2D3. Serum FGF23 remained high and PTH was unaffected. WT-SPR4 mice developed hypophosphatemia and hypercalcemia with increased PTH, FGF23 and 1.25(OH)2D3. SPR4 increased GAPDH HYP-bone expression 60× and corrected HYP-mice hyperglycemia and hypoinsulinemia. HYP-VE serum uric-acid (UA) levels were reduced and SPR4 infusion suppressed UA levels in WT-mice but not HYP-mice. SPR4 altered leptin, adiponectin, and sympathetic-tone and increased the fat mass/weight ratio for HYP and WT mice. Expression of perlipin-2 a gene involved in obesity was reduced in HYP-VE and WT-SPR4 mice but increased in HYP-SPR4 mice. Also, increased expression of two genes that inhibit insulin-signaling, ENPP1 and ESP, occurred with HYP-VE mice. In contrast, SPR4 reduced expression of both ENPP1 and ESP in WT mice and suppressed ENPP1 in HYP mice. Increased expression of FAM20C and sclerostin occurred with HYP-VE mice. SPR4 suppressed expression of FAM20C and sclerostin in HYP and WT mice. Conclusions ASARM peptides and motifs are physiological substrates for PHEX and modulate osteocyte PHEX-DMP1-α5β3-integrin interactions and thereby FGF23 expression. These interactions also provide a nexus that regulates bone and energy metabolism. SPR4 suppression of

  9. Wild-type phosphoribosylpyrophosphate synthase (PRS) from Mycobacterium tuberculosis: a bacterial class II PRS?

    PubMed

    Breda, Ardala; Martinelli, Leonardo K B; Bizarro, Cristiano V; Rosado, Leonardo A; Borges, Caroline B; Santos, Diógenes S; Basso, Luiz A

    2012-01-01

    The 5-phospho-α-D-ribose 1-diphosphate (PRPP) metabolite plays essential roles in several biosynthetic pathways, including histidine, tryptophan, nucleotides, and, in mycobacteria, cell wall precursors. PRPP is synthesized from α-D-ribose 5-phosphate (R5P) and ATP by the Mycobacterium tuberculosis prsA gene product, phosphoribosylpyrophosphate synthase (MtPRS). Here, we report amplification, cloning, expression and purification of wild-type MtPRS. Glutaraldehyde cross-linking results suggest that MtPRS predominates as a hexamer, presenting varied oligomeric states due to distinct ligand binding. MtPRS activity measurements were carried out by a novel coupled continuous spectrophotometric assay. MtPRS enzyme activity could be detected in the absence of P(i). ADP, GDP and UMP inhibit MtPRS activity. Steady-state kinetics results indicate that MtPRS has broad substrate specificity, being able to accept ATP, GTP, CTP, and UTP as diphosphoryl group donors. Fluorescence spectroscopy data suggest that the enzyme mechanism for purine diphosphoryl donors follows a random order of substrate addition, and for pyrimidine diphosphoryl donors follows an ordered mechanism of substrate addition in which R5P binds first to free enzyme. An ordered mechanism for product dissociation is followed by MtPRS, in which PRPP is the first product to be released followed by the nucleoside monophosphate products to yield free enzyme for the next round of catalysis. The broad specificity for diphosphoryl group donors and detection of enzyme activity in the absence of P(i) would suggest that MtPRS belongs to Class II PRS proteins. On the other hand, the hexameric quaternary structure and allosteric ADP inhibition would place MtPRS in Class I PRSs. Further data are needed to classify MtPRS as belonging to a particular family of PRS proteins. The data here presented should help augment our understanding of MtPRS mode of action. Current efforts are toward experimental structure determination of

  10. Subcellular localization of Mayven following expression of wild type and mutant EGFP tagged cDNAs

    PubMed Central

    2010-01-01

    Background Process formation by glial cells is crucial to their function. Mayven, an actin binding, multi-domain polypeptide, and member of the BTB-BACK-Kelch family have been shown to be important in oligodendrocyte process extension. To assess the role of Mayven in neural cell process extension we have tracked the subcellular distribution of exogenous Mayven following expression of a rat Mayven -EGFP cDNA in a variety of neural cell backgrounds and specifically in OEC tranfectants following drug treatment to disrupt the integrity of the cytoskeleton. A comparison was made between the subcellular localization following transient transfection of OECs with full-length Mayven cDNA and a series of mutant domain constructs. Results The subcellular location of Mayven in OEC transfectants showed a characteristic distribution with intense foci of staining towards the process tips corresponding to regions of accumulated Mayven overlapping in part with lammelipodial actin and was absent from the filipodia and the outer membrane. This signature pattern was also observed in Schwann cells, Oli-Neu cells, astrocytes and the neuroblastoma cell line B104 transfectants and resembled the exogenous and endogenous Mayven distribution in oligodendrocytes. This contrasted with the localization pattern in non-neural cells. There was a re-localization of Mayven in OEC transfectants following drug treatment to challenge the integrity of the actin cytoskeleton while breakdown of the microtubular component had no discernible impact on the accumulation of Mayven in the process tips. Deletion of the first three amino acids of the SH3 motif of the putative Fyn Kinase binding domain at the amino terminus significantly compromised this signature pattern as did the removal of the last Kelch repeat unit of six unit Kelch domain comprising the carboxyl terminus. In addition, there was a reduction in process length in mutant transfectants. Co-expression studies with a haemagglutinin (HA) tagged wild

  11. miR-181a shows tumor suppressive effect against oral squamous cell carcinoma cells by downregulating K-ras

    SciTech Connect

    Shin, Ki-Hyuk; Bae, Susan D.; Hong, Hannah S.; Kim, Reuben H.; Kang, Mo K.; Park, No-Hee

    2011-01-28

    Research highlights: {yields} MicroRNA-181a (miR-181a) was frequently downregulated in oral squamous cell carcinoma (OSCC). {yields} Overexpression of miR-181a suppressed OSCC growth. {yields} K-ras is a novel target of miR-181a. {yields} Decreased miR-181a expression is attributed to its lower promoter activity in OSCC. -- Abstract: MicroRNAs (miRNAs) are epigenetic regulators of gene expression, and their deregulation plays an important role in human cancer, including oral squamous cell carcinoma (OSCC). Recently, we found that miRNA-181a (miR-181a) was upregulated during replicative senescence of normal human oral keratinocytes. Since senescence is considered as a tumor suppressive mechanism, we thus investigated the expression and biological role of miR-181a in OSCC. We found that miR-181a was frequently downregulated in OSCC. Ectopic expression of miR-181a suppressed proliferation and anchorage independent growth ability of OSCC. Moreover, miR-181a dramatically reduces the growth of OSCC on three dimensional organotypic raft culture. We also identified K-ras as a novel target of miR-181a. miR-181a decreased K-ras protein level as well as the luciferase activity of reporter vectors containing the 3'-untranslated region of K-ras gene. Finally, we defined a minimal regulatory region of miR-181a and found a positive correlation between its promoter activity and the level of miR-181a expression. In conclusion, miR-181a may function as an OSCC suppressor by targeting on K-ras oncogene. Thus, miR-181a should be considered for therapeutic application for OSCC.

  12. Cadmium tolerance, cysteine and thiol peptide levels in wild type and chromium-tolerant strains of Scenedesmus acutus (Chlorophyceae).

    PubMed

    Torricelli, Elena; Gorbi, Gessica; Pawlik-Skowronska, Barbara; Di Toppi, Luigi Sanità; Corradi, Maria Grazia

    2004-07-14

    Two strains of the unicellular green alga Scenedesmus acutus with different sensitivity to hexavalent chromium were compared for their tolerance of cadmium, by means of growth and recovery tests, and determination of cysteine, reduced glutathione and phytochelatin content, after short-term exposure to various cadmium concentrations (from 1.125 to 27 microM). Growth experiments showed that, after 7-day treatments with cadmium, the chromium-tolerant strain reached a significantly higher cell density and, after 24-h exposure to Cd, was able to resume growth significantly better than the wild type. Constitutive level of cysteine was higher in the chromium-tolerant strain, while glutathione levels were similar in the two strains. The higher content of cysteine and the maintenance of both reduced glutathione and phytochelatin high levels in the presence of cadmium, support the higher cadmium co-tolerance of the chromium-tolerant strain in comparison with the wild type one. PMID:15177949

  13. Small N-terminal mutant huntingtin fragments, but not wild type, are mainly present in monomeric form: Implications for pathogenesis.

    PubMed

    Cong, Shu-Yan; Pepers, Barry A; Roos, Raymund A C; van Ommen, Gert-Jan B; Dorsman, Josephine C

    2006-06-01

    N-terminal fragments of huntingtin containing an expanded polyglutamine stretch play an important role in the molecular pathogenesis of Huntington's disease. Their ultimate accumulation in insoluble protein aggregates constitutes an important pathological hallmark of Huntington's disease. We report on systematic biochemical comparison studies of soluble wild type and mutant N-terminal huntingtin fragments. The results show that soluble wild type exon 1 fragments are predominantly present in higher molecular weight complexes with a molecular size of approximately 300 kDa, while their mutant counterparts are mainly present in their monomeric form. In contrast, longer N-terminal fragments corresponding to peptides produced by caspase cleavage do not display these differential properties. These findings suggest that especially an increased amount of monomeric form of small N-terminal mutant huntingtin fragments may facilitate aberrant interactions both with itself via the polyglutamine stretch and with other proteins and thereby contribute to molecular pathogenesis. PMID:16380118

  14. A PCR-based assay for the wild-type dystrophin gene transferred into the mdx mouse.

    PubMed

    Shrager, J B; Naji, A; Kelly, A M; Stedman, H H

    1992-10-01

    Myoblast transfer has emerged as a promising treatment for inherited myopathies such as Duchenne muscular dystrophy (DMD). Further development of the technique's therapeutic potential requires an experimental system in which issues of graft rejection can be clearly discriminated from those related to myoblast biology. Here we report the development and initial application of a quantitative assay for myogenic cells bearing a wild-type dystrophin gene following transfer into the mdx mouse. The technique relies upon the ability of a mutagenizing polymerase chain reaction (PCR) primer to create a new restriction site in the amplification production of the wild-type, but not the mdx dystrophin gene. The ratio of host to donor cells can be determined from muscle biopsies as small as 1 mg, regardless of donor H-2 background. This simple technique should allow a number of basic questions related to myoblast and direct gene transfer to be addressed using the mdx mouse model. PMID:1357549

  15. Structural variability between starch granules in wild type and in ae high-amylose mutant maize kernels.

    PubMed

    Liu, Dongli; Parker, Mary L; Wellner, Nikolaus; Kirby, Andrew R; Cross, Kathryn; Morris, Victor J; Cheng, Fang

    2013-09-12

    Starch granule structure within wild-type and ae high-amylose mutant maize kernels has been mapped in situ using light, electron and atomic force microscopy, and both Raman and infra-red spectroscopy. The population of wild-type starch granules is found to be homogenous. The ae mutant granule population is heterogeneous. Heterogeneity in chemical and physical structure is observed within individual granules, between granules within cells, and spatially within the kernel. The highest level of heterogeneity is observed in the region where starch is first deposited during kernel development. Light microscopy demonstrates structural diversity through use of potassium iodide/iodine staining and polarised microscopy. Electron and atomic force microscopy, and infra-red and Raman spectroscopy defined the nature of the structural changes within granules. The methodology provides novel information on the changes in starch structure resulting from kernel development. PMID:23911471

  16. EXAFS of Klebsiella pneumoniae nitrogenase MoFe protein from wild-type and nif V mutant strains

    SciTech Connect

    Eidsness, M.K.; Flank, A.M.; Smith, B.E.; Flood, A.C.; Garner, C.D.; Cramer. S.P.

    1986-05-14

    The enzyme nitrogenase catalyzes the biological reduction of N/sub 2/ to NH/sub 3/. In Klebsiella pneumoniae a cluster of 17 genes in seven transcriptional units has been associated with nitrogen fixation. The nitrogenase enzyme from the nif V mutants is relatively ineffective at dinitrogen reduction, is more efficient than the wild-type enzyme at HCN reduction, and has its hydrogen evolution activity inhibited up to 80% by CO. This altered substrate specificity has been shown to be associated with the iron-molybdenum cofactor, FeMo-co, of the enzyme. X-ray absorption spectroscopy has been a valuable tool for probing the molybdenum environment of wild-type nitrogenase, and the authors report here similar studies on the Nif V/sup -/ enzyme.

  17. Full Genome Sequence-Based Comparative Study of Wild-Type and Vaccine Strains of Infectious Laryngotracheitis Virus from Italy.

    PubMed

    Piccirillo, Alessandra; Lavezzo, Enrico; Niero, Giulia; Moreno, Ana; Massi, Paola; Franchin, Elisa; Toppo, Stefano; Salata, Cristiano; Palù, Giorgio

    2016-01-01

    Infectious laryngotracheitis (ILT) is an acute and highly contagious respiratory disease of chickens caused by an alphaherpesvirus, infectious laryngotracheitis virus (ILTV). Recently, full genome sequences of wild-type and vaccine strains have been determined worldwide, but none was from Europe. The aim of this study was to determine and analyse the complete genome sequences of five ILTV strains. Sequences were also compared to reveal the similarity of strains across time and to discriminate between wild-type and vaccine strains. Genomes of three ILTV field isolates from outbreaks occurred in Italy in 1980, 2007 and 2011, and two commercial chicken embryo origin (CEO) vaccines were sequenced using the 454 Life Sciences technology. The comparison with the Serva genome showed that 35 open reading frames (ORFs) differed across the five genomes. Overall, 54 single nucleotide polymorphisms (SNPs) and 27 amino acid differences in 19 ORFs and two insertions in the UL52 and ORFC genes were identified. Similarity among the field strains and between the field and the vaccine strains ranged from 99.96% to 99.99%. Phylogenetic analysis revealed a close relationship among them, as well. This study generated data on genomic variation among Italian ILTV strains revealing that, even though the genetic variability of the genome is well conserved across time and between wild-type and vaccine strains, some mutations may help in differentiating among them and may be involved in ILTV virulence/attenuation. The results of this study can contribute to the understanding of the molecular bases of ILTV pathogenicity and provide genetic markers to differentiate between wild-type and vaccine strains. PMID:26890525

  18. Wild-type p53 protein undergoes cytoplasmic sequestration in undifferentiated neuroblastomas but not in differentiated tumors.

    PubMed Central

    Moll, U M; LaQuaglia, M; Bénard, J; Riou, G

    1995-01-01

    Neuroblastoma (NB), a tumor arising from the sympathetic nervous system, is one of the most common malignancies in childhood. Several recent reports on the p53 genotype found virtually exclusive wild-type status in primary tumors, and it was postulated that p53 plays no role in the development of NB. Here, however, we report that the vast majority of undifferentiated NBs exhibit abnormal cytoplasmic sequestration of wild-type p53. This inability of p53 to translocate to the nucleus presumably prevents the protein from functioning as a suppressor. Thirty of 31 cases (96%) of undifferentiated NB showed elevated levels of wild-type p53 in the cytoplasm of all tumor cells concomittant with a lack of nuclear staining. p53 immunoprecipitation from tumor tissues showed a 4.5- to 8-fold increase over normal protein levels. All of 10 tumors analyzed harbored wild-type p53 by direct sequencing of full-length cDNA and Southern blot. In addition, no MDM-2 gene amplification was seen in all 11 tumors analyzed. In contrast, no p53 abnormality was detected in 14 differentiated ganglioneuroblastomas and 1 benign ganglioneuroma. We conclude that loss of p53 function seems to play a major role in the tumorigenesis of undifferentiated NB. This tumor might abrogate the transactivating function of p53 by inhibiting its access to the nucleus, rather than by gene mutation. Importantly, our results suggest that (i) this could be a general mechanism for p53 inactivation not limited to breast cancer (where we first described it) and that (ii) it is found in a tumor previously not thought to be affected by p53 alteration. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:7753819

  19. Effect of lectin on nodulation by wild-type Bradyrhizobium japonicum and a nodulation-defective mutant.

    PubMed Central

    Halverson, L J; Stacey, G

    1986-01-01

    The nodulation characteristics of wild-type Bradyrhizobium japonicum USDA 110 and mutant strain HS111 were examined. Mutant strain HS111 exhibits a delayed-nodulation phenotype, a result of its inability to initiate successful nodulation promptly following inoculation of the soybean root. Previously, we showed that the defect in initiation of infection leading to subsequent nodulation which is found in HS111 can be phenotypically reversed by pretreatment with soybean root exudate or soybean seed lectin. This effect is not seen after pretreatment with root exudates and lectins obtained from other plant species. Treatment of strain HS111 with as little as 10 soybean seed lectin molecules per bacterium (3.3 X 10 (-12) M) resulted in enhancement of nodule formation. Pretreatment of wild-type B. japonicum USDA 110 with soybean root exudate or seed lectin increased nodule numbers twofold on 6-week-old plants. Wild-type strain USDA 110 cells inoculated at 10(4) cells per seedling exhibited a delay in initiation of infection leading to subsequent nodulation. Wild-type cells pretreated in soybean root exudates or seed lectin did not exhibit a delay in nodulation at this cell concentration. Mutant strain HS111 pretreated in seed lectin for 0 or 1 h, followed by washing with the hapten D-galactose to remove the lectin, exhibited a delay in initiation of nodulation. Phenotypic reversal of the delayed-nodulation phenotype exhibited by strain HS111 was seen if incubation was continued for an additional 71 h in plant nutrient solution following 1 h of lectin pretreatment. Reversal of the delayed-nodulation phenotype of HS111 through lectin pretreatment was prevented by chloramphenicol or rifampin.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3707122

  20. Functional independence of monomeric CHIP28 water channels revealed by expression of wild-type mutant heterodimers.

    PubMed

    Shi, L B; Skach, W R; Verkman, A S

    1994-04-01

    CHIP28 is a major water transporting protein in erythrocytes and kidney which forms tetramers in membranes (Verbavatz, J. M., Brown, D., Sabolic, I., Valenti, G., Ausiello, D. A., Van Hoek, A. N., Ma, T., and Verkman, A. S. (1993) J. Cell Biol. 123, 605-618). To determine whether CHIP28 monomers function independently, chimeric cDNA dimers were constructed which contained wild-type CHIP28 in series with either wild-type CHIP28, a non-water transporting CHIP28 mutant (C189W), or a functional but mercurial-insensitive CHIP28 mutant (C189S). Transcribed cRNAs were injected in Xenopus oocytes and plasma membrane expression was assayed by quantitative immunofluorescence. Water channel function was measured by osmotically induced swelling. CHIP28 homo- and heterodimers were targeted to the oocyte plasma membrane and functioned as water channels. Relative osmotic water permeability (Pf) values (normalized for plasma membrane expression of monomeric subunits) were: 1.0 (CHIP28 monomer), 0.0 (C189W), 1.07 (C189S), 1.10 (CHIP28-CHIP28 dimer) and 0.52 (CHIP28-C189W). The increase in oocyte Pf was linearly related to plasma membrane expression of wild-type CHIP28 and C189S subunits. HgCl2 (0.3 mM) inhibited channel-mediated Pf in oocytes expressing wild-type CHIP28 monomers and dimers by 85-90%, but did not inhibit Pf in oocytes expressing C189S. HgCl2 inhibited Pf in oocytes expressing CHIP28-C189S dimers by 44 +/- 7%, consistent with one mercurial-sensitive and one insensitive subunit in the heterodimer. These results indicate that despite their assembly in tetramers, monomeric CHIP28 subunits function independently as water channels. PMID:7511600

  1. Posttranslational Modifications in Type I Collagen from Different Tissues Extracted from Wild Type and Prolyl 3-Hydroxylase 1 Null Mice*

    PubMed Central

    Pokidysheva, Elena; Zientek, Keith D.; Ishikawa, Yoshihiro; Mizuno, Kazunori; Vranka, Janice A.; Montgomery, Nathan T.; Keene, Douglas R.; Kawaguchi, Tatsuya; Okuyama, Kenji; Bächinger, Hans Peter

    2013-01-01

    Type I collagen extracted from tendon, skin, and bone of wild type and prolyl 3-hydroxylase 1 (P3H1) null mice shows distinct patterns of 3-hydroxylation and glycosylation of hydroxylysine residues. The A1 site (Pro-986) in the α1-chain of type I collagen is almost completely 3-hydroxylated in every tissue of the wild type mice. In contrast, no 3-hydroxylation of this proline residue was found in P3H1 null mice. Partial 3-hydroxylation of the A3 site (Pro-707) was present in tendon and bone, but absent in skin in both α-chains of the wild type animals. Type I collagen extracted from bone of P3H1 null mice shows a large reduction in 3-hydroxylation of the A3 site in both α-chains, whereas type I collagen extracted from tendon of P3H1 null mice shows little difference as compared with wild type. These results demonstrate that the A1 site in type I collagen is exclusively 3-hydroxylated by P3H1, and presumably, this enzyme is required for the 3-hydroxylation of the A3 site of both α-chains in bone but not in tendon. The increase in glycosylation of hydroxylysine in P3H1 null mice in bone was found to be due to an increased occupancy of normally glycosylated sites. Despite the severe disorganization of collagen fibrils in adult tissues, the D-period of the fibrils is unchanged. Tendon fibrils of newborn P3H1 null mice are well organized with only a slight increase in diameter. The absence of 3-hydroxyproline and/or the increased glycosylation of hydroxylysine in type I collagen disturbs the lateral growth of the fibrils. PMID:23861401

  2. Full Genome Sequence-Based Comparative Study of Wild-Type and Vaccine Strains of Infectious Laryngotracheitis Virus from Italy

    PubMed Central

    Niero, Giulia; Moreno, Ana; Massi, Paola; Franchin, Elisa; Toppo, Stefano; Salata, Cristiano; Palù, Giorgio

    2016-01-01

    Infectious laryngotracheitis (ILT) is an acute and highly contagious respiratory disease of chickens caused by an alphaherpesvirus, infectious laryngotracheitis virus (ILTV). Recently, full genome sequences of wild-type and vaccine strains have been determined worldwide, but none was from Europe. The aim of this study was to determine and analyse the complete genome sequences of five ILTV strains. Sequences were also compared to reveal the similarity of strains across time and to discriminate between wild-type and vaccine strains. Genomes of three ILTV field isolates from outbreaks occurred in Italy in 1980, 2007 and 2011, and two commercial chicken embryo origin (CEO) vaccines were sequenced using the 454 Life Sciences technology. The comparison with the Serva genome showed that 35 open reading frames (ORFs) differed across the five genomes. Overall, 54 single nucleotide polymorphisms (SNPs) and 27 amino acid differences in 19 ORFs and two insertions in the UL52 and ORFC genes were identified. Similarity among the field strains and between the field and the vaccine strains ranged from 99.96% to 99.99%. Phylogenetic analysis revealed a close relationship among them, as well. This study generated data on genomic variation among Italian ILTV strains revealing that, even though the genetic variability of the genome is well conserved across time and between wild-type and vaccine strains, some mutations may help in differentiating among them and may be involved in ILTV virulence/attenuation. The results of this study can contribute to the understanding of the molecular bases of ILTV pathogenicity and provide genetic markers to differentiate between wild-type and vaccine strains. PMID:26890525

  3. Purification and some properties of wild-type and N-terminal-truncated ethanolamine ammonia-lyase of Escherichia coli.

    PubMed

    Akita, Keita; Hieda, Naoki; Baba, Nobuyuki; Kawaguchi, Satoshi; Sakamoto, Hirohisa; Nakanishi, Yuka; Yamanishi, Mamoru; Mori, Koichi; Toraya, Tetsuo

    2010-01-01

    The methods of homologous high-level expression and simple large-scale purification for coenzyme B(12)-dependent ethanolamine ammonia-lyase of Escherichia coli were developed. The eutB and eutC genes in the eut operon encoded the large and small subunits of the enzyme, respectively. The enzyme existed as the heterododecamer alpha(6)beta(6). Upon active-site titration with adeninylpentylcobalamin, a strong competitive inhibitor for coenzyme B(12), the binding of 1 mol of the inhibitor per mol of the alphabeta unit caused complete inhibition of enzyme, in consistent with its subunit structure. EPR spectra indicated the formation of substrate-derived radicals during catalysis and the binding of cobalamin in the base-on mode, i.e. with 5,6-dimethylbenzimidazole coordinating to the cobalt atom. The purified wild-type enzyme underwent aggregation and inactivation at high concentrations. Limited proteolysis with trypsin indicated that the N-terminal region is not essential for catalysis. His-tagged truncated enzymes were similar to the wild-type enzyme in catalytic properties, but more resistant to p-chloromercuribenzoate than the wild-type enzyme. A truncated enzyme was highly soluble even in the absence of detergent and resistant to aggregation and oxidative inactivation at high concentrations, indicating that a short N-terminal sequence is sufficient to change the solubility and stability of the enzyme. PMID:19762342

  4. Protective efficacy of low-dose amantadine in adults challenged with wild-type influenza A virus.

    PubMed Central

    Sears, S D; Clements, M L

    1987-01-01

    The prophylactic efficacy of a low dose (100 mg) of amantadine hydrochloride against experimental challenge with influenza A/Texas/1/85 (H1N1) wild-type virus was determined in healthy adult volunteers in a placebo-controlled, double-blind, randomized trial. No side effects of the 100-mg dose were observed in the amantadine-treated volunteers. Compared with placebo, 100 mg of amantadine significantly reduced the frequency of illness (9 of 22 versus 2 of 22 volunteers, P less than 0.04) and provided 78% protection against influenza illness. The two ill volunteers in the amantadine group had rhinitis only, whereas most of the ill placebo controls developed both systemic and upper-respiratory-tract illness. Wild-type virus was recovered from 50% of the amantadine-treated volunteers, compared with 82% of the placebo controls. Of note, the infected amantadine recipients shed 100 times less virus and shed virus for half as many days as did the infected placebo recipients. Although amantadine restricted viral replication, it did not interfere with the development of an antibody response to influenza virus. These results indicate that in adults experimentally challenged with influenza wild-type virus, 100 mg of amantadine is effective both in the prevention of influenza illness and in the restriction of virus replication. PMID:3435099

  5. Activation of ganglion cells in wild-type and rd1 mouse retinas with monophasic and biphasic current pulses

    NASA Astrophysics Data System (ADS)

    Jensen, Ralph J.; Rizzo, Joseph F. III

    2009-06-01

    We and other research groups are designing an electronic retinal prosthesis to provide vision for patients who are blind due to photoreceptor degeneration. In this study, we examined the effect of stimulus waveform on the amount of current needed to activate retinal ganglion cells (RGCs) when the retinal neural network is stimulated. Isolated retinas of wild-type and rd1 mice were stimulated with cathodal and anodal monophasic current pulses of 1 ms duration and symmetric biphasic current pulses (1 ms per phase) delivered through an electrode that was located subretinally. For both wild-type and rd1 mouse retinas, cathodal current pulses were least effective in activating most RGCs. The median threshold current for a cathodal current pulse was 2.0-4.4 fold higher than the median threshold current for either an anodal or a biphasic current pulse. In wild-type mouse retinas, the median threshold current for activating RGCs with anodal current pulses was 23% lower than that with biphasic current pulses. In rd1 mouse retinas, the median threshold currents for anodal and biphasic current pulses were about the same. However, the variance in thresholds of rd1 RGCs for biphasic pulse stimulation was much smaller than for anodal pulse stimulation. Thus, a symmetric biphasic current pulse may be the best stimulus for activating the greatest number of RGCs in retinas devoid of photoreceptors.

  6. Cellular Oxidative Stress and the Control of Apoptosis by Wild-Type p53, Cytotoxic Compounds, and Cytokines

    NASA Astrophysics Data System (ADS)

    Lotem, Joseph; Peled-Kamar, Mira; Groner, Yoram; Sachs, Leo

    1996-08-01

    Apoptosis induced by wild-type p53 or cytotoxic compounds in myeloid leukemic cells can be inhibited by the cytokines interleukin 6, interleukin 3, granulocyte-macrophage colony-stimulating factor, and interferon γ and by antioxidants. The antioxidants and cytokines showed a cooperative protective effect against induction of apoptosis. Cells with a higher sensitivity to induction of apoptosis and required a higher cytokine concentration to inhibit apoptosis. Decreasing the intrinsic oxidative stress in cells by antioxidants thus inhibited apoptosis, whereas increasing this intrinsic stress by adding H2O2 enhanced apoptosis. Induction of apoptosis by wild-type p53 was not preceded by increased peroxide production or lipid peroxidation and the protective effect of cytokines was not associated with a decrease in these properties. The results indicate that the intrinsic degree of oxidative stress can regulate cell susceptibility to wild-type p53-dependent and p53-independent induction of apoptosis and the ability of cytokines to protect cells against apoptosis.

  7. Processing of CFTR bearing the P574H mutation differs from wild-type and deltaF508-CFTR.

    PubMed

    Ostedgaard, L S; Zeiher, B; Welsh, M J

    1999-07-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) containing the deltaF508 mutation is retained in the endoplasmic reticulum (ER). This defect can be partially overcome by a reduction in temperature which allows some of the deltaF508 protein to exit the ER and move to the cell surface. Earlier studies showed that the CF-associated mutants, P574H and A455E, were also misprocessed. In this study, we found that processing of P574H and A455E was also temperature-sensitive; at 26 degrees C, some of the protein matured. In contrast to other CFTR mutants, P574H accumulated in punctate cytoplasmic bodies that colocalized with endoplasmic reticulum (ER) markers. At 26 degrees C, these bodies were no longer present. P574H showed a prolonged association with Hsp70 and also colocalized with Hsp70. We used brefeldin A (BFA) to determine which processing step(s) was altered by reduced temperature. Unlike wild-type CFTR, which was converted into an intermediate that was stable in the presence of BFA at 37 degrees C, deltaF508 and P574H produced the intermediate only when the temperature was reduced to 26 degrees C. Furthermore the wild-type intermediate was not associated with Hsp70. These data suggest that formation of the stable intermediate is a key temperature-sensitive step and appears to be coincident with release of the wild-type protein from Hsp70. PMID:10362539

  8. The fusion protein of wild-type canine distemper virus is a major determinant of persistent infection

    SciTech Connect

    Plattet, Philippe; Rivals, Jean-Paul; Zuber, BenoIt; Brunner, Jean-Marc; Zurbriggen, Andreas; Wittek, Riccardo . E-mail: Riccardo.Wittek@unil.ch

    2005-07-05

    The wild-type A75/17 canine distemper virus (CDV) strain induces a persistent infection in the central nervous system but infects cell lines very inefficiently. In contrast, the genetically more distant Onderstepoort CDV vaccine strain (OP-CDV) induces extensive syncytia formation. Here, we investigated the roles of wild-type fusion (F{sub WT}) and attachment (H{sub WT}) proteins in Vero cells expressing, or not, the canine SLAM receptor by transfection experiments and by studying recombinants viruses expressing different combinations of wild-type and OP-CDV glycoproteins. We show that low fusogenicity is not due to a defect of the envelope proteins to reach the cell surface and that H{sub WT} determines persistent infection in a receptor-dependent manner, emphasizing the role of SLAM as a potent enhancer of fusogenicity. However, importantly, F{sub WT} reduced cell-to-cell fusion independently of the cell surface receptor, thus demonstrating that the fusion protein of the neurovirulent A75/17-CDV strain plays a key role in determining persistent infection.

  9. Transfection of wild-type CFTR into cystic fibrosis lymphocytes restores chloride conductance at G1 of the cell cycle.

    PubMed Central

    Krauss, R D; Bubien, J K; Drumm, M L; Zheng, T; Peiper, S C; Collins, F S; Kirk, K L; Frizzell, R A; Rado, T A

    1992-01-01

    We complemented the Cl- conductance defect in cystic fibrosis lymphocytes by transfection with wild-type cDNA for the cystic fibrosis transmembrane conductance regulator (CFTR). Stable transfectants were selected and subjected to molecular and functional analyses. We detected expression of endogenous CFTR mRNA in several CF and non-CF lymphoid cell lines by PCR. Expression from cDNA in the transfectants was demonstrated by amplifying vector-specific sequences. Both fluorescence and patch-clamp assays showed that transfectants expressing wild-type CFTR acquired properties previously associated with Cl- conductance (GCl) regulation in non-CF lymphocytes: (i) GCl was elevated in the G1 phase of the cell cycle, (ii) cells fixed at G1 increase GCl in response to increased cellular cAMP or Ca2+, (iii) agonist-induced increases in GCl were lost as the cells progressed to the S phase of the cell cycle. The cell cycle and agonist dependent regulation of GCl was not observed in CF lymphocytes transfected with CFTR cDNA containing stop codons in all reading frames at exon 6. Our findings indicate that lymphocytes express functional CFTR since wild-type CFTR corrects the defects in Cl- conductance regulation found in CF lymphocytes. Evaluation of the mechanism of this novel, CFTR-mediated regulation of GCl during cell cycling should provide further insights into the function of CFTR. Images PMID:1372253

  10. Targeting cytokine networks in KRAS-driven tumorigenesis.

    PubMed

    Golay, Hadrien G; Barbie, David A

    2014-08-01

    KRAS is one of the most commonly mutated oncogenes in human tumors, and is typically associated with aggressive disease. Despite intensive study and years of effort, KRAS has remained refractory to targeted inhibition. Given the challenge of inhibiting KRAS directly, current approaches to KRAS targeted therapy have involved the disruption of downstream signaling pathways. However, combinations of drugs that target RAF/MEK and PI3K/AKT signaling have failed to live up to expectations in the clinic. Here we summarize the evidence that the cytokine signaling circuitry of KRAS-driven tumors represents an equally tractable drug target. Indeed, the incorporation of novel therapeutics that disrupts these cytokine signaling networks may hold the key to overcoming this seemingly impenetrable treatment barrier. PMID:24928447

  11. KRAS Mutations in Canine and Feline Pancreatic Acinar Cell Carcinoma.

    PubMed

    Crozier, C; Wood, G A; Foster, R A; Stasi, S; Liu, J H W; Bartlett, J M S; Coomber, B L; Sabine, V S

    2016-07-01

    Companion animals may serve as valuable models for studying human cancers. Although KRAS is the most commonly mutated gene in human ductal pancreatic cancers (57%), with mutations frequently occurring at codons 12, 13 and 61, human pancreatic acinar cell carcinomas (ACCs) lack activating KRAS mutations. In the present study, 32 pancreatic ACC samples obtained from 14 dogs and 18 cats, including seven metastases, were analyzed for six common activating KRAS mutations located in codons 12 (n = 5) and 13 (n = 1) using Sequenom MassARRAY. No KRAS mutations were found, suggesting that, similar to human pancreatic ACC, KRAS mutations do not play a critical role in feline or canine pancreatic ACC. Due to the similarity of the clinical disease in dogs and cats to that of man, this study confirms that companion animals offer potential as a suitable model for investigating this rare subtype of pancreatic carcinoma. PMID:27290644

  12. Crystallization and preliminary X-ray crystallographic study of the wild type and two mutants of the CP1 hydrolytic domain from Aquifex aeolicus leucyl-tRNA synthetase

    SciTech Connect

    Cura, Vincent; Olieric, Natacha; Guichard, Alexandre; Moras, Dino; Cavarelli, Jean

    2005-10-01

    The wild-type editing CP1 domain of A. aeolicus leucyl-tRNA synthetase and two mutant CP1 domains have been overexpressed, purified and crystallized. X-ray diffraction data have been collected to 1.8 Å, which has enabled determination of the structures by molecular replacement. The editing or hydrolytic CP1 domain of leucyl-tRNA synthetase (LeuRS) hydrolyses several misactivated amino acids. The CP1 domain of Aquifex aeolicus LeuRS was expressed, purified and crystallized by the hanging-drop vapour-diffusion method using ammonium sulfate as precipitant. Crystals belong to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 38.8, b = 98.4, c = 116.7 Å. Crystals diffract to beyond 1.8 Å resolution and contain two monomers in the asymmetric unit. Two CP1 mutants in which a conserved threonine residue essential for the fidelity of the hydrolytic pathway is mutated to alanine or glutamic acid have also been expressed and crystallized. Crystals of the two CP1 mutants are isomorphs of the wild type and diffract to beyond 1.9 Å resolution. All structures were solved by molecular-replacement techniques.

  13. Enhanced lignin biodegradation by a laccase-overexpressed white-rot fungus Polyporus brumalis in the pretreatment of wood chips.

    PubMed

    Ryu, Sun-Hwa; Cho, Myung-Kil; Kim, Myungkil; Jung, Sang-Min; Seo, Jin-Ho

    2013-11-01

    The laccase gene of Polyporus brumalis was genetically transformed to overexpress its laccase. The transformants exhibited increased laccase activity and effective decolorization of the dye Remazol Brilliant Blue R than the wild type. When the transformants were pretreated with wood chips from a red pine (softwood) and a tulip tree (hardwood) for 15 and 45 days, they showed higher lignin-degradation activity as well as higher wood-chip weight loss than the wild type. When the wood chips treated with the transformant were enzymatically saccharified, the highest sugar yields were found to be 32.5 % for the red pine wood and 29.5 % for the tulip tree wood, on the basis of the dried wood weights, which were 1.6-folds higher than those for the wild type. These results suggested that overexpression of the laccase gene from P. brumalis significantly contributed to the pretreatment of lignocellulose for increasing sugar yields. PMID:23975277

  14. Clonal dynamics following p53 loss of heterozygosity in Kras-driven cancers.

    PubMed

    Muzumdar, Mandar Deepak; Dorans, Kimberly Judith; Chung, Katherine Minjee; Robbins, Rebecca; Tammela, Tuomas; Gocheva, Vasilena; Li, Carman Man-Chung; Jacks, Tyler

    2016-01-01

    Although it has become increasingly clear that cancers display extensive cellular heterogeneity, the spatial growth dynamics of genetically distinct clones within developing solid tumours remain poorly understood. Here we leverage mosaic analysis with double markers (MADM) to trace subclonal populations retaining or lacking p53 within oncogenic Kras-initiated lung and pancreatic tumours. In both models, p53 constrains progression to advanced adenocarcinomas. Comparison of lineage-related p53 knockout and wild-type clones reveals a minor role of p53 in suppressing cell expansion in lung adenomas. In contrast, p53 loss promotes both the initiation and expansion of low-grade pancreatic intraepithelial neoplasia (PanINs), likely through differential expression of the p53 regulator p19ARF. Strikingly, lineage-related cells are often dispersed in lung adenomas and PanINs, contrasting with more contiguous growth of advanced subclones. Together, these results support cancer type-specific suppressive roles of p53 in early tumour progression and offer insights into clonal growth patterns during tumour development. PMID:27585860

  15. Overexpression of agouti protein and stress responsiveness in mice.

    PubMed

    Harris, R B; Zhou, J; Shi, M; Redmann, S; Mynatt, R L; Ryan, D H

    2001-07-01

    Ectopic overexpression of agouti protein, an endogenous antagonist of melanocortin receptors' linked to the beta-actin promoter (BAPa) in mice, produces a phenotype of yellow coat color, Type II diabetes, obesity and increased somatic growth. Spontaneous overexpression of agouti increases stress-induced weight loss. In these experiments, other aspects of stress responsiveness were tested in 12-week-old male wild-type mice and BAPa mice. Two hours of restraint on three consecutive days produced greater increases in corticosterone and post-stress weight loss in BAPa than wild-type mice. In Experiment 2, anxiety-type behavior was measured immediately after 12 min of restraint. This mild stress did not produce many changes indicative of anxiety, but BAPa mice spent more time in the dark side of a light-dark box and less time in the open arms of an elevated plus maze than restrained wild-type mice. In a defensive withdrawal test, grooming was increased by restraint in all mice, but the duration of each event was substantially shorter in BAPa mice, possibly due to direct antagonism of the MC4-R by agouti protein. Thus, BAPa mice showed exaggerated endocrine and energetic responses to restraint stress with small differences in anxiety-type behavior compared with wild-type mice. These results are consistent with observations in other transgenic mice in which the melanocortin system is disrupted, but contrast with reports that acute blockade of central melanocortin receptors inhibits stress-induced hypophagia. Thus, the increased stress responsiveness in BAPa mice may be a developmental compensation for chronic inhibition of melanocortin receptors. PMID:11495665

  16. Oncogenic KRAS Regulates Tumor Cell Signaling via Stromal Reciprocation.

    PubMed

    Tape, Christopher J; Ling, Stephanie; Dimitriadi, Maria; McMahon, Kelly M; Worboys, Jonathan D; Leong, Hui Sun; Norrie, Ida C; Miller, Crispin J; Poulogiannis, George; Lauffenburger, Douglas A; Jørgensen, Claus

    2016-05-01

    Oncogenic mutations regulate signaling within both tumor cells and adjacent stromal cells. Here, we show that oncogenic KRAS (KRAS(G12D)) also regulates tumor cell signaling via stromal cells. By combining cell-specific proteome labeling with multivariate phosphoproteomics, we analyzed heterocellular KRAS(G12D) signaling in pancreatic ductal adenocarcinoma (PDA) cells. Tumor cell KRAS(G12D) engages heterotypic fibroblasts, which subsequently instigate reciprocal signaling in the tumor cells. Reciprocal signaling employs additional kinases and doubles the number of regulated signaling nodes from cell-autonomous KRAS(G12D). Consequently, reciprocal KRAS(G12D) produces a tumor cell phosphoproteome and total proteome that is distinct from cell-autonomous KRAS(G12D) alone. Reciprocal signaling regulates tumor cell proliferation and apoptosis and increases mitochondrial capacity via an IGF1R/AXL-AKT axis. These results demonstrate that oncogene signaling should be viewed as a heterocellular process and that our existing cell-autonomous perspective underrepresents the extent of oncogene signaling in cancer. VIDEO ABSTRACT. PMID:27087446

  17. Oncogenic KRAS confers chemoresistance by upregulating NRF2

    PubMed Central

    Tao, Shasha; Wang, Shue; Moghaddam, Seyed Javad; Ooi, Aikseng; Chapman, Eli; Wong, Pak K.; Zhang, Donna D.

    2014-01-01

    Oncogenic KRAS mutations found in 20–30% of all non-small cell lung cancers (NSCLC) are associated with chemoresistance and poor prognosis. Here we demonstrate that activation of the cell protective stress response gene NRF2 by KRAS is responsible for its ability to promote drug resistance. RNAi-mediated silencing of NRF2 was sufficient to reverse resistance to cisplatin elicited by ectopic expression of oncogenic KRAS in NSCLC cells. Mechanistically, KRAS increased NRF2 gene transcription through a TPA response element (TRE) located in the NRF2 promoter. In a mouse model of mutant KrasG12D-induced lung cancer, we found that suppressing the NRF2 pathway with the chemical inhibitor brusatol enhanced the antitumor efficacy of cisplatin. Co-treatment reduced tumor burden and improved survival. Our findings illuminate the mechanistic details of KRAS-mediated drug resistance and provide a preclinical rationale to improve the management of lung tumors harboring KRAS mutations with NRF2 pathway inhibitors. PMID:25339352

  18. Study of phytochelatins and other related thiols as complexing biomolecules of As and Cd in wild type and genetically modified Brassica juncea plants.

    PubMed

    Navaza, Ana Pereira; Montes-Bayón, Maria; LeDuc, Danika L; Terry, Norman; Sanz-Medel, Alfredo

    2006-03-01

    The accumulation of As and Cd in Brassica juncea plants and the formation of complexes of these elements with bioligands such as glutathione and/or phytochelatins (PCs) is studied. The genetic manipulation of these plants to induce higher As and Cd accumulation has been achieved by overexpressing the genes encoding for gamma-glutamyl cysteine synthetase (gamma-ECS) and glutathione synthetase (GS). These two enzymes are responsible for glutathione (GSH) formation in plants, which is the first step in the production of PCs. The biomass produced in both the wild type and the genetically modified plants, has been evaluated. Additionally, the total Cd and As concentration accumulated in the plant tissues was measured by inductively coupled plasma mass spectrometry (ICP-MS) after extraction. Speciation studies on the extracts were conducted using size exclusion liquid chromatography (SEC) coupled online with ICP-MS to monitor As, Cd and S. For further purification of the As fractions, reversed phase high performance liquid chromatography (RP-HPLC) was used. Structural elucidation of the PCs and other thiols, as well as their complexes with As and Cd, was performed by electrospray-quadrupole-time-of-flight (ESI-Q-TOF). In both the Cd and As exposed plants it was possible to observe the presence of oxidized PC2 ([M + H]+, m/z 538), GS-PC2(-Glu) ([M + H]+, m/z 716) as well as reduced GSH ([M + H]+, m/z 308) and oxidized glutathione (GSSG) ([M + H]+, m/z 613). However, only the GS plants exhibited the presence of As(GS)3 complex ([M + H]+, m/z 994) that was further confirmed by MS/MS. This species is reported for the first time in B. juncea plant tissues. PMID:16421878

  19. Bone Turnover in Wild Type and Pleiotrophin-Transgenic Mice Housed for Three Months in the International Space Station (ISS)

    PubMed Central

    Brun, Francesco; Canciani, Barbara; Manescu, Adrian; Marozzi, Katia; Cilli, Michele; Costa, Delfina; Liu, Yi; Piccardi, Federica; Tasso, Roberta; Tromba, Giuliana; Rustichelli, Franco; Cancedda, Ranieri

    2012-01-01

    Bone is a complex dynamic tissue undergoing a continuous remodeling process. Gravity is a physical force playing a role in the remodeling and contributing to the maintenance of bone integrity. This article reports an investigation on the alterations of the bone microarchitecture that occurred in wild type (Wt) and pleiotrophin-transgenic (PTN-Tg) mice exposed to a near-zero gravity on the International Space Station (ISS) during the Mice Drawer System (MDS) mission, to date, the longest mice permanence (91 days) in space. The transgenic mouse strain over-expressing pleiotrophin (PTN) in bone was selected because of the PTN positive effects on bone turnover. Wt and PTN-Tg control animals were maintained on Earth either in a MDS payload or in a standard vivarium cage. This study revealed a bone loss during spaceflight in the weight-bearing bones of both strains. For both Tg and Wt a decrease of the trabecular number as well as an increase of the mean trabecular separation was observed after flight, whereas trabecular thickness did not show any significant change. Non weight-bearing bones were not affected. The PTN-Tg mice exposed to normal gravity presented a poorer trabecular organization than Wt mice, but interestingly, the expression of the PTN transgene during the flight resulted in some protection against microgravity’s negative effects. Moreover, osteocytes of the Wt mice, but not of Tg mice, acquired a round shape, thus showing for the first time osteocyte space-related morphological alterations in vivo. The analysis of specific bone formation and resorption marker expression suggested that the microgravity-induced bone loss was due to both an increased bone resorption and a decreased bone deposition. Apparently, the PTN transgene protection was the result of a higher osteoblast activity in the flight mice. PMID:22438896

  20. Pharmacological activation of wild-type p53 in the therapy of leukemia.

    PubMed

    Kojima, Kensuke; Ishizawa, Jo; Andreeff, Michael

    2016-09-01

    The tumor suppressor p53 is inactivated by mutations in the majority of human solid tumors. Conversely, p53 mutations are rare in leukemias and are only observed in a small fraction of the patient population, predominately in patients with complex karyotype acute myeloid leukemia or hypodiploid acute lymphoblastic leukemia. However, the loss of p53 function in leukemic cells is often caused by abnormalities in p53-regulatory proteins, including overexpression of MDM2/MDMX, deletion of CDKN2A/ARF, and alterations in ATM. For example, MDM2 inhibits p53-mediated transcription, promotes its nuclear export, and induces proteasome-dependent degradation. The MDM2 homolog MDMX is another direct regulator of p53 that inhibits p53-mediated transcription. Several small-molecule inhibitors and stapled peptides targeting MDM2 and MDMX have been developed and have recently entered clinical trials. The clinical trial results of the first clinically used MDM2 inhibitor, RG7112, illustrated promising p53 activation and apoptosis induction in leukemia cells as proof of concept. Side effects of RG7112 were most prominent in suppression of thrombopoiesis and gastrointestinal symptoms in leukemia patients. Predictive biomarkers for response to MDM2 inhibitors have been proposed, but they require further validation both in vitro and in vivo so that the accumulated knowledge concerning pathological p53 dysregulation in leukemia and novel molecular-targeted strategies to overcome this dysregulation can be translated safely and efficiently into novel clinical therapeutics. PMID:27327543

  1. Genome wide interactions of wild-type and activator bypass forms of σ54.

    PubMed

    Schaefer, Jorrit; Engl, Christoph; Zhang, Nan; Lawton, Edward; Buck, Martin

    2015-09-01

    Enhancer-dependent transcription involving the promoter specificity factor σ(54) is widely distributed amongst bacteria and commonly associated with cell envelope function. For transcription initiation, σ(54)-RNA polymerase yields open promoter complexes through its remodelling by cognate AAA+ ATPase activators. Since activators can be bypassed in vitro, bypass transcription in vivo could be a source of emergent gene expression along evolutionary pathways yielding new control networks and transcription patterns. At a single test promoter in vivo bypass transcription was not observed. We now use genome-wide transcription profiling, genome-wide mutagenesis and gene over-expression strategies in Escherichia coli, to (i) scope the range of bypass transcription in vivo and (ii) identify genes which might alter bypass transcription in vivo. We find little evidence for pervasive bypass transcription in vivo with only a small subset of σ(54) promoters functioning without activators. Results also suggest no one gene limits bypass transcription in vivo, arguing bypass transcription is strongly kept in check. Promoter sequences subject to repression by σ(54) were evident, indicating loss of rpoN (encoding σ(54)) rather than creating rpoN bypass alleles would be one evolutionary route for new gene expression patterns. Finally, cold-shock promoters showed unusual σ(54)-dependence in vivo not readily correlated with conventional σ(54) binding-sites. PMID:26082500

  2. Extracellular enzyme activities during lignocellulose degradation by Streptomyces spp. : a comparative study of wild-type and genetically manipulated strains

    SciTech Connect

    Ramachandra, M.; Crawford, D.L.; Pometto, A.L. III

    1987-12-01

    The wild-type ligninolytic actinomycete Streptomyces viridosporus T7A and two genetically manipulated strains with enhanced abilities to produce a water-soluble lignin degradation intermediate, an acid-precipitable polymeric lignin (APPL), were grown on lignocellulose in solid-state fermentation cultures. Culture filtrates were periodically collected, analyzed for APPL, and assayed for extracellular lignocellulose-catabolizing enzyme activities. Two APPL-overproducing strains, UV irradiation mutant T7A-81 and protoplast fusion recombinant SR-10, had higher and longer persisting peroxidase, esterase, and endoglucanase activities than did the wild-type strain T7A. Results implicated one or more of these enzymes in lignin solubilization. Only mutant T7A-81 had higher xylanase activity than the wild type. The peroxidase was induced by both lignocellulose and APPL. This extracellular enzyme has some similarities to previously described ligninases in fungi. This is the first report of such an enzyme in Streptomyces spp. Four peroxidase isozymes were present, and all catalyzed the oxidation of 3,4-dihydroxyphenylalanine, while one also catalyzed hydrogen peroxide-dependent oxidation of homoprotocatechuic acid and caffeic acid. Three constitutive esterase isozymes were produced which differed in substrate specificity toward ..cap alpha..-naphthyl acetate and ..cap alpha..-naphthyl butyrate. Three endoglucanase bands, which also exhibited a low level of xylanase activity, were identified on polyacrylamide gels as was one xylanase-specific band. There were no major differences in the isoenzymes produced by the different strains. The probable role of each enzyme in lignocellulose degradation is discussed.

  3. Expression of mutant and wild-type TIMP3 in primary gingival fibroblasts from Sorsby's fundus dystrophy patients.

    PubMed

    Arris, Christine E; Bevitt, Debra J; Mohamed, Jeseem; Li, Zheng; Langton, Kevin P; Barker, Michael D; Clarke, Michael P; McKie, Norman

    2003-05-20

    Gingival fibroblast cell lines were derived from Sorsby's fundus dystrophy (SFD) patients carrying the S181C TIMP3 and the E139X TIMP3 mutations. These cell lines were grown in culture to study expression of the wild-type and mutant tissue inhibitor of metalloproteinase 3 (TIMP3) alleles from a normal diploid cell type. Firstly, patient cells were found to co-express the wild-type and mutant TIMP3 alleles, S181C TIMP3 or E139X TIMP3, at the mRNA level using restriction fragment length polymorphism (RFLP) analysis. A SpeI RFLP for E139X TIMP3 is described. Low levels of endogenous TIMP3 protein expression were elevated using the natural polysaccharide calcium pentosan polysulfate (CaPPs) in combination with the cytokine IL-1alpha. Immunoblotting detected protein expression from both wild-type and mutant alleles, S181C TIMP3 or E139X TIMP3. S181C TIMP3 from these cells was found to dimerise and retain MMP2 inhibitory activity. To facilitate studies of the E139X TIMP3 protein, the allele was expressed using HighFive insect cells. In this cell type, the E139X TIMP3 was synthesised as a mixture of monomer and dimer. Both monomeric and dimeric E139X TIMP3 protein retained MMP2 inhibitory activity in gelatin zymography. Expression of mutant E139X or S181C TIMP3 protein from a normal diploid patient-derived fibroblast cell had no effect on either MMP2 or MMP9 expression or activation whilst transcribed from their normal promoter context. PMID:12757930

  4. Heterogeneity of KRAS Mutation Status in Rectal Cancer

    PubMed Central

    Jo, Peter; König, Alexander; Schirmer, Markus; Kitz, Julia; Conradi, Lena-Christin; Azizian, Azadeh; Bernhardt, Markus; Wolff, Hendrik A.; Grade, Marian; Ghadimi, Michael; Ströbel, Philipp; Schildhaus, Hans-Ulrich; Gaedcke, Jochen

    2016-01-01

    Introduction Anti-EGFR targeted therapy is of increasing importance in advanced colorectal cancer and prior KRAS mutation testing is mandatory for therapy. However, at which occasions this should be performed is still under debate. We aimed to assess in patients with locally advanced rectal cancer whether there is intra-specimen KRAS heterogeneity prior to and upon preoperative chemoradiotherapy (CRT), and if there are any changes in KRAS mutation status due to this intervention. Materials and Methods KRAS mutation status analyses were performed in 199 tumor samples from 47 patients with rectal cancer. To evaluate the heterogeneity between different tumor areas within the same tumor prior to preoperative CRT, 114 biopsies from 34 patients (mean 3 biopsies per patient) were analyzed (pre-therapeutic intratumoral heterogeneity). For the assessment of heterogeneity after CRT residual tumor tissue (85 samples) from 12 patients (mean 4.2 tissue samples per patient) were analyzed (post-therapeutic intratumoral heterogeneity) and assessment of heterogeneity before and after CRT was evaluated in corresponding patient samples (interventional heterogeneity). Primer extension method (SNaPshot™) was used for initial KRAS mutation status testing for Codon 12, 13, 61, and 146. Discordant results by this method were reevaluated by using the FDA-approved KRAS Pyro Kit 24, V1 and the RAS Extension Pyro Kit 24, V1 Kit (therascreen® KRAS test). Results For 20 (43%) out of the 47 patients, a KRAS mutation was detected. With 12 out of 20, the majority of these mutations affected codon 35. We did not obtained evidence that CRT results in changes of the KRAS mutation pattern. In addition, no intratumoral heterogeneity in the KRAS mutational status could be proven. This was true for both the biopsies prior to CRT and the resection specimens thereafter. The discrepancy observed in some samples when using the SNaPshot™ assay was due to insufficient sensitivity of this technique upon

  5. The progressive nature of Wallerian degeneration in wild-type and slow Wallerian degeneration (WldS) nerves

    PubMed Central

    Beirowski, Bogdan; Adalbert, Robert; Wagner, Diana; Grumme, Daniela S; Addicks, Klaus; Ribchester, Richard R; Coleman, Michael P

    2005-01-01

    Background The progressive nature of Wallerian degeneration has long been controversial. Conflicting reports that distal stumps of injured axons degenerate anterogradely, retrogradely, or simultaneously are based on statistical observations at discontinuous locations within the nerve, without observing any single axon at two distant points. As axon degeneration is asynchronous, there are clear advantages to longitudinal studies of individual degenerating axons. We recently validated the study of Wallerian degeneration using yellow fluorescent protein (YFP) in a small, representative population of axons, which greatly improves longitudinal imaging. Here, we apply this method to study the progressive nature of Wallerian degeneration in both wild-type and slow Wallerian degeneration (WldS) mutant mice. Results In wild-type nerves, we directly observed partially fragmented axons (average 5.3%) among a majority of fully intact or degenerated axons 37–42 h after transection and 40–44 h after crush injury. Axons exist in this state only transiently, probably for less than one hour. Surprisingly, axons degenerated anterogradely after transection but retrogradely after a crush, but in both cases a sharp boundary separated intact and fragmented regions of individual axons, indicating that Wallerian degeneration progresses as a wave sequentially affecting adjacent regions of the axon. In contrast, most or all WldS axons were partially fragmented 15–25 days after nerve lesion, WldS axons degenerated anterogradely independent of lesion type, and signs of degeneration increased gradually along the nerve instead of abruptly. Furthermore, the first signs of degeneration were short constrictions, not complete breaks. Conclusions We conclude that Wallerian degeneration progresses rapidly along individual wild-type axons after a heterogeneous latent phase. The speed of progression and its ability to travel in either direction challenges earlier models in which clearance of

  6. Accumulation of a bioactive benzoisochromanequinone compound kalafungin by a wild type antitumor-medermycin-producing streptomycete strain.

    PubMed

    Lü, Jin; He, Qiang; Huang, Luyao; Cai, Xiaofeng; Guo, Wenwen; He, Jing; Zhang, Lili; Li, Aiying

    2015-01-01

    Medermycin and kalafungin, two antibacterial and antitumor antibiotics isolated from different streptomycetes, share an identical polyketide skeleton core. The present study reported the discovery of kalafungin in a medermycin-producing streptomycete strain for the first time. A mutant strain obtained through UV mutagenesis showed a 3-fold increase in the production of this antibiotic, compared to the wild type strain. Heterologous expression experiments suggested that its production was severely controlled by the gene cluster for medermycin biosynthesis. In all, these findings suggested that kalafungin and medermycin could be accumulated by the same streptomycete and share their biosynthetic pathway to some extent in this strain. PMID:25695632

  7. Accumulation of a Bioactive Benzoisochromanequinone Compound Kalafungin by a Wild Type Antitumor-Medermycin-Producing Streptomycete Strain

    PubMed Central

    Lü, Jin; He, Qiang; Huang, Luyao; Cai, Xiaofeng; Guo, Wenwen; He, Jing; Zhang, Lili; Li, Aiying

    2015-01-01

    Medermycin and kalafungin, two antibacterial and antitumor antibiotics isolated from different streptomycetes, share an identical polyketide skeleton core. The present study reported the discovery of kalafungin in a medermycin-producing streptomycete strain for the first time. A mutant strain obtained through UV mutagenesis showed a 3-fold increase in the production of this antibiotic, compared to the wild type strain. Heterologous expression experiments suggested that its production was severely controlled by the gene cluster for medermycin biosynthesis. In all, these findings suggested that kalafungin and medermycin could be accumulated by the same streptomycete and share their biosynthetic pathway to some extent in this strain. PMID:25695632

  8. Visualization of Melanosome Dynamics within Wild-Type and Dilute Melanocytes Suggests a Paradigm for Myosin V Function In Vivo

    PubMed Central

    Wu, Xufeng; Bowers, Blair; Rao, Kang; Wei, Qin; Hammer, John A.

    1998-01-01

    Unlike wild-type mouse melanocytes, where melanosomes are concentrated in dendrites and dendritic tips, melanosomes in dilute (myosin Va−) melanocytes are concentrated in the cell center. Here we sought to define the role that myosin Va plays in melanosome transport and distribution. Actin filaments that comprise a cortical shell running the length of the dendrite were found to exhibit a random orientation, suggesting that myosin Va could drive the outward spreading of melanosomes by catalyzing random walks. In contrast to this mechanism, time lapse video microscopy revealed that melanosomes undergo rapid (∼1.5 μm/s) microtubule-dependent movements to the periphery and back again. This bidirectional traffic occurs in both wild-type and dilute melanocytes, but it is more obvious in dilute melanocytes because the only melanosomes in their periphery are those undergoing this movement. While providing an efficient means to transport melanosomes to the periphery, this component does not by itself result in their net accumulation there. These observations, together with previous studies showing extensive colocalization of myosin Va and melanosomes in the actin-rich periphery, suggest a mechanism in which a myosin Va–dependent interaction of melanosomes with F-actin in the periphery prevents these organelles from returning on microtubules to the cell center, causing their distal accumulation. This “capture” model is supported by the demonstration that (a) expression of the myosin Va tail domain within wild-type cells creates a dilute-like phenotype via a process involving initial colocalization of tail domains with melanosomes in the periphery, followed by an ∼120-min, microtubule-based redistribution of melanosomes to the cell center; (b) microtubule-dependent melanosome movement appears to be damped by myosin Va; (c) intermittent, microtubule-independent, ∼0.14 μm/s melanosome movements are seen only in wild-type melanocytes; and (d) these movements do

  9. Enhanced water stress tolerance of transgenic maize plants over-expressing LEA Rab28 gene.

    PubMed

    Amara, Imen; Capellades, Montserrat; Ludevid, M Dolors; Pagès, Montserrat; Goday, Adela

    2013-06-15

    Late Embryogenesis Abundant (LEA) proteins participate in plant stress responses and contribute to the acquisition of desiccation tolerance. In this report Rab28 LEA gene has been over-expressed in maize plants under a constitutive maize promoter. The expression of Rab28 transcripts led to the accumulation and stability of Rab28 protein in the transgenic plants. Native Rab28 protein is localized to nucleoli in wild type maize embryo cells; here we find by whole-mount immunocytochemistry that in root cells of Rab28 transgenic and wild-type plants the protein is also associated to nucleolar structures. Transgenic plants were tested for stress tolerance and resulted in sustained growth under polyethyleneglycol (PEG)-mediated dehydration compared to wild-type controls. Under osmotic stress transgenic seedlings showed increased leaf and root areas, higher relative water content (RWC), reduced chlorophyll loss and lower Malondialdehyde (MDA) production in relation to wild-type plants. Moreover, transgenic seeds exhibited higher germination rates than wild-type seeds under water deficit. Overall, our results highlight the presence of transgenic Rab28 protein in nucleolar structures and point to the potential of group 5 LEA Rab28 gene as candidate to enhance stress tolerance in maize plants. PMID:23384757

  10. Herbicidal and antioxidant responses of transgenic rice overexpressing Myxococcus xanthus protoporphyrinogen oxidase.

    PubMed

    Jung, Sunyo; Back, Kyoungwhan

    2005-05-01

    We analyzed the herbicidal and antioxidant defense responses of transgenic rice plants that overexpressed the Myxococcus xanthus protoporphyrinogen oxidase gene. Leaf squares of the wild-type incubated with oxyfluorfen were characterized by necrotic leaf lesions and increases in conductivity and malonyldialdehyde levels, whereas transgenic lines M4 and M7 did not show any change with up to 100 microM oxyfluorfen. The wild-type had decreased F(v)/F(m) and produced a high level of H(2)O(2) at 18 h after foliar application of oxyfluorfen, whereas transgenic lines M4 and M7 were unaffected. In response to oxyfluorfen, violaxanthin, beta-carotene, and chlorophylls (Chls) decreased in wild-type plants, whereas antheraxanthin and zeaxanthin increased. Only a slight decline in Chls was observed in transgenic lines at 48 h after oxyfluorfen treatment. Noticeable increases of cytosolic Cu/Zn-superoxide dismutase, peroxidase isozymes 1 and 2, and catalase were observed after at 48 h of oxyfluorfen treatment in the wild-type. Non-enzymatic antioxidants appeared to respond faster to oxyfluorfen-induced photodynamic stress than did enzymatic antioxidants. Protective responses for the detoxification of active oxygen species were induced to counteract photodynamic stress in oxyfluorfen-treated, wild-type plants. However, oxyfluorfen-treated, transgenic plants suffered less oxidative stress, confirming increased herbicidal resistance resulted from dual expression of M. xanthus Protox in chloroplasts and mitochondria. PMID:15890521

  11. Safety of intravenous administration of a canarypox virus encoding the human wild-type p53 gene in colorectal cancer patients.

    PubMed

    Menon, Anand G; Kuppen, Peter J K; van der Burg, Sjoerd H; Offringa, Rienk; Bonnet, Marie Claude; Harinck, Bert I J; Tollenaar, Rob A E M; Redeker, Anke; Putter, Hein; Moingeon, Philippe; Morreau, Hans; Melief, Cornelis J M; van de Velde, Cornelis J H

    2003-07-01

    Overexpression of p53 occurs in more than 50% of colorectal cancers. Therefore, p53 represents an attractive target antigen for immunotherapy. We assessed the safety of a canarypox virus encoding the human wild-type p53 gene given intravenously to end-stage colorectal cancer patients in a three-step dose escalation study aimed at inducing p53 immune responses. Patients with metastatic disease of p53-overexpressing colorectal cancers were vaccinated three times at 3-week intervals, each time with 10(6.5) CCID(50) (CCID(50)=cell culture infectious dose 50%; group 1, n=5), 10(7.0) CCID(50) (group 2, n=5) or 10(7.5) CCID(50) (group 3, n=6). Vital signs and the occurrence of adverse events were monitored and blood was analyzed for biochemical and hematological parameters as well as signs of auto-immune safety. In all, 16 patients were enrolled and 15 patients completed three vaccinations. No anaphylactic reaction or unwanted auto-immune reactions were observed. A total of 16 serious adverse events (SAEs) occurred: 10 in group 1, three in group 2 and three in group 3. All SAEs were tumor-related complications. There was no difference in the frequency of adverse events between the three groups, except for fever. Fever was the only vaccination-related adverse event consistently observed and was most frequent and outspoken in the group 3 patients. The majority was a grade 1 or 2 fever (93%) and grade 3 fever (7%) was observed in three patients of group 3. Some patients showed humoral and cellular responses against p53, following vaccinations. After having completed his initial treatment cycle, one patient (group 2) received a second treatment cycle of three doses of 10(7.5) CCID(50) and subsequently showed stable disease. All other patients showed progressive disease. We conclude that ALVAC-p53 can be administered intravenously to colorectal cancer patients without serious toxicity or pathological autoimmunity and can induce immune responses against p53. PMID:12833131

  12. Cadmium tolerance and phytochelatin content of Arabidopsis seedlings over-expressing the phytochelatin synthase gene AtPCS1

    PubMed Central

    Brunetti, Patrizia; Zanella, Letizia; Proia, Alessandra; De Paolis, Angelo; Falasca, Giuseppina; Altamura, Maria Maddalena; Sanità di Toppi, Luigi; Costantino, Paolo; Cardarelli, Maura

    2011-01-01

    Previous studies demonstrated that expression of the Arabidopsis phytochelatin (PC) biosynthetic gene AtPCS1 in Nicotiana tabacum plants increases the Cd tolerance in the presence of exogenous glutathione (GSH). In this paper, the Cd tolerance of Arabidopsis plants over-expressing AtPCS1 (AtPCSox lines) has been analysed and the differences between Arabidopsis and tobacco are shown. Based on the analysis of seedling fresh weight, primary root length, and alterations in root anatomy, evidence is provided that, at relatively low Cd concentrations, the Cd tolerance of AtPCSox lines is lower than the wild type, while AtPCS1 over-expressing tobacco is more tolerant to Cd than the wild type. At higher Cd concentrations, Arabidopsis AtPCSox seedlings are more tolerant to Cd than the wild type, while tobacco AtPCS1 seedlings are as sensitive as the wild type. Exogenous GSH, in contrast to what was observed in tobacco, did not increase the Cd tolerance of AtPCSox lines. The PC content in wild-type Arabidopsis at low Cd concentrations is more than three times higher than in tobacco and substantial differences were also found in the PC chain lengths. These data indicate that the differences in Cd tolerance and in its dependence on exogenous GSH between Arabidopsis and tobacco are due to species-specific differences in the endogenous content of PCs and GSH and may be in the relative abundance of PCs of different length. PMID:21841172

  13. Cadmium tolerance and phytochelatin content of Arabidopsis seedlings over-expressing the phytochelatin synthase gene AtPCS1.

    PubMed

    Brunetti, Patrizia; Zanella, Letizia; Proia, Alessandra; De Paolis, Angelo; Falasca, Giuseppina; Altamura, Maria Maddalena; Sanità di Toppi, Luigi; Costantino, Paolo; Cardarelli, Maura

    2011-11-01

    Previous studies demonstrated that expression of the Arabidopsis phytochelatin (PC) biosynthetic gene AtPCS1 in Nicotiana tabacum plants increases the Cd tolerance in the presence of exogenous glutathione (GSH). In this paper, the Cd tolerance of Arabidopsis plants over-expressing AtPCS1 (AtPCSox lines) has been analysed and the differences between Arabidopsis and tobacco are shown. Based on the analysis of seedling fresh weight, primary root length, and alterations in root anatomy, evidence is provided that, at relatively low Cd concentrations, the Cd tolerance of AtPCSox lines is lower than the wild type, while AtPCS1 over-expressing tobacco is more tolerant to Cd than the wild type. At higher Cd concentrations, Arabidopsis AtPCSox seedlings are more tolerant to Cd than the wild type, while tobacco AtPCS1 seedlings are as sensitive as the wild type. Exogenous GSH, in contrast to what was observed in tobacco, did not increase the Cd tolerance of AtPCSox lines. The PC content in wild-type Arabidopsis at low Cd concentrations is more than three times higher than in tobacco and substantial differences were also found in the PC chain lengths. These data indicate that the differences in Cd tolerance and in its dependence on exogenous GSH between Arabidopsis and tobacco are due to species-specific differences in the endogenous content of PCs and GSH and may be in the relative abundance of PCs of different length. PMID:21841172

  14. PEP3 overexpression shortens lag phase but does not alter growth rate in Saccharomyces cerevisiae exposed to acetic acid stress.

    PubMed

    Ding, Jun; Holzwarth, Garrett; Bradford, C Samuel; Cooley, Ben; Yoshinaga, Allen S; Patton-Vogt, Jana; Abeliovich, Hagai; Penner, Michael H; Bakalinsky, Alan T

    2015-10-01

    In fungi, two recognized mechanisms contribute to pH homeostasis: the plasma membrane proton-pumping ATPase that exports excess protons and the vacuolar proton-pumping ATPase (V-ATPase) that mediates vacuolar proton uptake. Here, we report that overexpression of PEP3 which encodes a component of the HOPS and CORVET complexes involved in vacuolar biogenesis, shortened lag phase in Saccharomyces cerevisiae exposed to acetic acid stress. By confocal microscopy, PEP3-overexpressing cells stained with the vacuolar membrane-specific dye, FM4-64 had more fragmented vacuoles than the wild-type control. The stained overexpression mutant was also found to exhibit about 3.6-fold more FM4-64 fluorescence than the wild-type control as determined by flow cytometry. While the vacuolar pH of the wild-type strain grown in the presence of 80 mM acetic acid was significantly higher than in the absence of added acid, no significant difference was observed in vacuolar pH of the overexpression strain grown either in the presence or absence of 80 mM acetic acid. Based on an indirect growth assay, the PEP3-overexpression strain exhibited higher V-ATPase activity. We hypothesize that PEP3 overexpression provides protection from acid stress by increasing vacuolar surface area and V-ATPase activity and, hence, proton-sequestering capacity. PMID:26051671

  15. Performance by Spring-Calving Cows Grazing Tall Fescue Pastures with Either the Wild-Type Toxic Endophyte or a Non-Toxic Novel Endophyte

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cows grazing 'Kentucky-31' tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] infected with its wild-type endophyte (Neotyphodium coenophialum; E+) generally display suboptimal performance. Recently, endophyte strains that do not produce compounds toxic to cattle have been incorporated into tall ...

  16. Viscoelasticity in wild-type and vinculin-deficient (5.51) mouse F9 embryonic carcinoma cells examined by atomic force microscopy and rheology.

    PubMed

    Goldmann, W H; Ezzell, R M

    1996-07-10

    We have been studying mouse F9 embryonic carcinoma cells which contain no detectable vinculin protein (5.51 cells), and compared them with F9 wild-type cells. Employing atomic force microscopy, we probed the elastic properties of individual F9 wild-type and 5.51 cells by measuring the dynamic response of controlled loads of the cantilever tip. An elastic modulus (Young) of approximately 3.8 and approximately 2.5 kPa was calculated for wild-type and 5.51 cells, respectively. Using disc rheometry, we detected a marked change in shear of a 1000g pellet of approximately 55 x 10(6) cells between wild-type and 5.51 mutants. These differences are attributed to the loss of vinculin and altered cytoskeletal organization in these cells. PMID:8660960

  17. Phenotypic expression of wild-type tomato and three wilty mutants in relation to abscisic acid accumulation in roots and leaflets of reciprocal grafts

    SciTech Connect

    Cornish, K.; Zeevaart, J.A.D. )

    1988-05-01

    Lycopersicon esculentum Mill. cv Rheinlands Ruhm (RR) and cv Moneymaker and the three wilty mutants flacca (flc), sitiens (sit), and sitiens{sup w} (sit{sup w}), together with the most reciprocal grafts, were grown in pots and in solution culture. Detached leaflets, and control and stem-girdled intact plants, were left turgid or were wilted in air. Detached leaflets and the leaflets and roots of the intact plants were analyzed for their abscisic acid (ABA) content. Turgid RR leaflets contained about 2.9 ng ABA per miligram dry weight. On average, the flc and sit leaflets contained 33 and 11% of this amount, respectively. The lack of ABA approximately correlated with the severity of the mutant phenotype. Mutant roots also contained less ABA than wild-type roots. Wild-type scions on mutant stocks (wild type/mutant) maintained the normal phenotype of ungrafted plants. Mutant scions grafted onto wild-type stocks reverted to a near wild-type phenotype. After the wild-type leaves were excised from solution culture-grown mutant/wild-type plants, the revertive morphology of the mutant scions was maintained, although endogenous ABA levels in the leaflets fell to typical mutant levels and the leaflets became wilty again. When stressed in air, both leaflets and roots of RR plants produced stress-induced ABA, but the mutant leaflets and roots did not. The roots and leaflets of the grafted plants behaved according to their own genotype, with the notable exception of mutant roots grown with wild-type scions. Roots of flc and sit{sup w} recovered the ability to accumulate stress-induced ABA when grafted with RR scions before the stress was imposed.

  18. Plastid Alternative Oxidase (PTOX) Promotes Oxidative Stress When Overexpressed in Tobacco

    PubMed Central

    Heyno, Eiri; Gross, Christine M.; Laureau, Constance; Culcasi, Marcel; Pietri, Sylvia; Krieger-Liszkay, Anja

    2009-01-01

    Photoinhibition and production of reactive oxygen species were studied in tobacco plants overexpressing the plastid terminal oxidase (PTOX). In high light, these plants was more susceptible to photoinhibition than wild-type plants. Also oxygen-evolving activity of isolated thylakoid membranes from the PTOX-overexpressing plants was more strongly inhibited in high light than in thylakoids from wild-type plants. In contrast in low light, in the PTOX overexpressor, the thylakoids were protected against photoinhibition while in wild type they were significantly damaged. The production of superoxide and hydroxyl radicals was shown by EPR spin-trapping techniques in the different samples. Superoxide and hydroxyl radical production was stimulated in the overexpressor. Two-thirds of the superoxide production was maintained in the presence of DNP-INT, an inhibitor of the cytochrome b6f complex. No increase of the SOD content was observed in the overexpressor compared with the wild type. We propose that superoxide is produced by PTOX in a side reaction and that PTOX can only act as a safety valve under stress conditions when the generated superoxide is detoxified by an efficient antioxidant system. PMID:19740740

  19. Cellular toxicity of yeast prion protein Rnq1 can be modulated by N-terminal wild type huntingtin.

    PubMed

    Sethi, Ratnika; Patel, Vishal; Saleh, Aliabbas A; Roy, Ipsita

    2016-01-15

    Aggregation of the N-terminal human mutant huntingtin and the consequent toxicity in the yeast model of Huntington's disease (HD) requires the presence of Rnq1 protein (Rnq1p) in its prion conformation [RNQ1(+)]. The understanding of interaction of wild-type huntingtin (wt-Htt) with the amyloidogenic prion has some gaps. In this work, we show that N-terminal fragment of wt-Htt (N-wt-Htt) ameliorated the toxic effect of [RNQ1(+)] depending on expression levels of both proteins. When the expression of N-wt-Htt was high, it increased the expression and delayed the aggregation of [RNQ1(+)]. As the expression of N-wt-Htt was reduced, it formed high molecular weight aggregates along with the prion. Even when sequestered by [RNQ1(+)], the beneficial effect of N-wt-Htt on expression of Rnq1p and on cell survival was evident. Huntingtin protein ameliorated toxicity due to the prion protein [RNQ1(+)] in yeast cells in a dose-dependent manner, resulting in increase in cell survival, hinting at its probable role as a component of the proteostasis network of the cell. Taking into account the earlier reports of the beneficial effect of expression of N-wt-Htt on the aggregation of mutant huntingtin, the function of wild-type huntingtin as an inhibitor of protein aggregation in the cell needs to be explored. PMID:26628321

  20. Fructose 6-phosphate phosphoketolase activity in wild-type strains of Lactobacillus, isolated from the intestinal tract of pigs.

    PubMed

    Bolado-Martínez, E; Acedo-Félix, E; Peregrino-Uriarte, A B; Yepiz-Plascencia, G

    2012-01-01

    Phosphoketolases are key enzymes of the phosphoketolase pathway of heterofermentative lactic acid bacteria, which include lactobacilli. In heterofermentative lactobacilli xylulose 5-phosphate phosphoketolase (X5PPK) is the main enzyme of the phosphoketolase pathway. However, activity of fructose 6-phosphate phosphoketolase (F6PPK) has always been considered absent in lactic acid bacteria. In this study, the F6PPK activity was detected in 24 porcine wild-type strains of Lactobacillus reuteri and Lactobacillus mucosae, but not in the Lactobacillus salivarius or in L. reuteri ATCC strains. The activity of F6PPK increased after treatment of the culture at low-pH and diminished after porcine bile-salts stress conditions in wild-type strains of L. reuteri. Colorimetric quantification at 505 nm allowed to differentiate between microbial strains with low activity and without the activity of F6PPK. Additionally, activity of F6PPK and the X5PPK gene expression levels were evaluated by real time PCR, under stress and nonstress conditions, in 3 L. reuteri strains. Although an exact correlation, between enzyme activity and gene expression was not obtained, it remains possible that the xpk gene codes for a phosphoketolase with dual substrate, at least in the analyzed strains of L. reuteri. PMID:23101386

  1. MLL fusion proteins preferentially regulate a subset of wild-type MLL target genes in the leukemic genome

    PubMed Central

    Wang, Qian-fei; Wu, George; Mi, Shuangli; He, Fuhong; Wu, Jun; Dong, Jingfang; Luo, Roger T.; Mattison, Ryan; Kaberlein, Joseph J.; Prabhakar, Shyam; Ji, Hongkai

    2011-01-01

    MLL encodes a histone methyltransferase that is critical in maintaining gene expression during embryonic development and hematopoiesis. 11q23 translocations result in the formation of chimeric MLL fusion proteins that act as potent drivers of acute leukemia. However, it remains unclear what portion of the leukemic genome is under the direct control of MLL fusions. By comparing patient-derived leukemic cell lines, we find that MLL fusion-bound genes are a small subset of that recognized by wild-type MLL. In an inducible MLL-ENL model, MLL fusion protein binding and changes in H3K79 methylation are limited to a specific portion of the genome, whereas wild-type MLL distributes to a much larger set of gene loci. Surprisingly, among 223 MLL-ENL–bound genes, only 12 demonstrate a significant increase in mRNA expression on induction of the fusion protein. In addition to Hoxa9 and Meis1, this includes Eya1 and Six1, which comprise a heterodimeric transcription factor important in several developmental pathways. We show that Eya1 has the capacity to immortalize hematopoietic progenitor cells in vitro and collaborates with Six1 in hematopoietic transformation assays. Altogether, our data suggest that MLL fusions contribute to the development of acute leukemia through direct activation of a small set of target genes. PMID:21518926

  2. Crystal Structures and Functional Characterization of Wild Type and Active Sites Mutants of CYP101D1

    PubMed Central

    Batabyal, Dipanwita; Poulos, Thomas L.

    2014-01-01

    Although CYP101D1 and P450cam catayze the same reaction at a similar rate and share strikingly similar active site architectures, there are significance functional differences. CYP101D1 thus provides an opportunity to probe what structural and functional features must be shared and what can differ yet maintain high catalytic efficiency. Crystal structures of the cyanide complex of wild type CYP101D1 and it active site mutants, D259N and T260A, have been solved. The conformational changes in CYP101D1 upon cyanide binding are very similar to P450cam indicating a similar mechanism for proton delivery during oxygen activation using solvent assisted proton transfer. The D259N-CN− complex shows a perturbed solvent structure compared to wild type which is similar to what was observed in the oxy-complex of the corresonding D251N mutant in P450cam. As in P450cam the T260A mutant is highly uncoupled while the D259N gives barely detectable activity. Despite these similarities, CYP101D1 is able to use the P450cam redox partners while P450cam cannot use the CYP101D1 redox partners. Thus the strict requirement of P450cam for its own redox partner is relaxed in CYP101D1. Differences in the local environment of the essential Asp (Asp259 in CYP101D1) provides a strucutral basis for understanding these functional differences. PMID:24261604

  3. Nitrosative damage to free and zinc-bound cysteine thiols underlies nitric oxide toxicity in wild-type Borrelia burgdorferi

    PubMed Central

    Bourret, Travis J; Boylan, Julie A; Lawrence, Kevin A; Gherardini, Frank C

    2011-01-01

    Borrelia burgdorferi encounters potentially harmful reactive nitrogen species (RNS) throughout its infective cycle. In this study, diethylamine NONOate (DEA/NO) was used to characterize the lethal effects of RNS on B. burgdorferi. RNS produce a variety of DNA lesions in a broad spectrum of microbial pathogens; however, levels of the DNA deamination product, deoxyinosine, and the numbers of apurinic/apyrimidinic (AP) sites were identical in DNA isolated from untreated and DEA/NO-treated B. burgdorferi cells. Strains with mutations in the nucleotide excision repair (NER) pathway genes uvrC or uvrB treated with DEA/NO had significantly higher spontaneous mutation frequencies, increased numbers of AP sites in DNA and reduced survival compared with wild-type controls. Polyunsaturated fatty acids in B. burgdorferi cell membranes, which are susceptible to peroxidation by reactive oxygen species (ROS), were not sensitive to RNS-mediated lipid peroxidation. However, treatment of B. burgdorferi cells with DEA/NO resulted in nitrosative damage to several proteins, including the zinc-dependent glycolytic enzyme fructose-1,6-bisphosphate aldolase (BB0445), the Borrelia oxidative stress regulator (BosR) and neutrophil-activating protein (NapA). Collectively, these data suggested that nitrosative damage to proteins harbouring free or zinc-bound cysteine thiols, rather than DNA or membrane lipids underlies RNS toxicity in wild-type B. burgdorferi. PMID:21564333

  4. Discovery of an inhibitor of the production of the Pseudomonas aeruginosa virulence factor pyocyanin in wild-type cells

    PubMed Central

    Morkunas, Bernardas; Gal, Balint; Galloway, Warren R J D; Hodgkinson, James T; Ibbeson, Brett M; Sing Tan, Yaw; Welch, Martin

    2016-01-01

    Summary Pyocyanin is a small molecule produced by Pseudomonas aeruginosa that plays a crucial role in the pathogenesis of infections by this notorious opportunistic pathogen. The inhibition of pyocyanin production has been identified as an attractive antivirulence strategy for the treatment of P. aeruginosa infections. Herein, we report the discovery of an inhibitor of pyocyanin production in cultures of wild-type P. aeruginosa which is based around a 4-alkylquinolin-2(1H)-one scaffold. To the best of our knowledge, this is the first reported example of pyocyanin inhibition by a compound based around this molecular framework. The compound may therefore be representative of a new structural sub-class of pyocyanin inhibitors, which could potentially be exploited in in a therapeutic context for the development of critically needed new antipseudomonal agents. In this context, the use of wild-type cells in this study is notable, since the data obtained are of direct relevance to native situations. The compound could also be of value in better elucidating the role of pyocyanin in P. aeruginosa infections. Evidence suggests that the active compound reduces the level of pyocyanin production by inhibiting the cell–cell signalling mechanism known as quorum sensing. This could have interesting implications; quorum sensing regulates a range of additional elements associated with the pathogenicity of P. aeruginosa and there is a wide range of other potential applications where the inhibition of quorum sensing is desirable. PMID:27559393

  5. Intra-host competition between nef-defective escape mutants and wild-type human immunodeficiency virus type 1.

    PubMed Central

    Altes, H K; Jansen, V A

    2000-01-01

    Various forms of nef genes with deletions at conserved positions along the sequence have been reported to persist in human immunodeficiency virus type 1 infected patients. We investigate the forces maintaining such variants in the proviral population. The main selection pressures are preservation of function and host immune response. The crippled Nef protein might have fewer epitopes, and as such be less visible to the specific immune response, but it will lose some function. Does a trade-off between avoidance of the immune response and loss of function explain the dynamics of the crippled virus found in the patients? To answer this question, we formulated a deterministic model of the virus-host interactions. We found that when the crippled protein presents few epitopes and suffers little loss of function, the two viral types can coexist. Otherwise, the wild-type comes to prevail. The mutant form might initially dominate, but as the selective pressure by the CD84+ T cells decreases over the course of infection, the advantage for the crippled form of losing epitopes disappears. Hence, we go from a situation of coexistence of wild-type and mutant, to a situation of only full-length nef. The results are discussed in the context of the suggested use of live attenuated vaccines having deletions in nef. PMID:10687825

  6. Prognosis and management of adult wild type gastrointestinal stromal tumours (GISTs): A pooled analysis and review of literature.

    PubMed

    Bhatt, N R; Collins, D; Crotty, P; Ridgway, P F

    2016-09-01

    A pooled review was performed to determine survival in adult WT GIST (Wild Type GastroIntestinal Stromal Tumours) and compare the same with pediatric WT GISTs. Electronic databases were searched using the terms "Wild type" AND "GIST". Eighty-two adult patients from 14 studies were included in the pooled analysis. Cumulative survival was greater than 50% in both age groups, hence medial survival could not be computed. Mean survival in adults was 15.7 years ± 0.78 and in children was 18.8 years ± 1.3 (p = 0.241). Median disease free survival in adults was 10 years while 5-year overall survival was 88%. There was no statistically significant difference in the survival between the two groups (p = 0.241). Overall survival in adults with WT GISTs is favourable compared to other adult GIST subtypes likely reflects a common molecular pathway similar to pediatric GIST. PMID:27566016

  7. Characteristics of alpha/beta interferon induction after infection of murine fibroblasts with wild-type and mutant alphaviruses

    SciTech Connect

    Burke, Crystal W.; Gardner, Christina L.; Steffan, Joshua J.; Ryman, Kate D.; Klimstra, William B.

    2009-12-05

    We examined the characteristics of interferon alpha/beta (IFN-alpha/beta) induction after alphavirus or control Sendai virus (SeV) infection of murine fibroblasts (MEFs). As expected, SeV infection of wild-type (wt) MEFs resulted in strong dimerization of IRF3 and the production of high levels of IFN-alpha/beta. In contrast, infection of MEFs with multiple alphaviruses failed to elicit detectable IFN-alpha/beta. In more detailed studies, Sindbis virus (SINV) infection caused dimerization and nuclear migration of IRF3, but minimal IFN-beta promoter activity, although surprisingly, the infected cells were competent for IFN production by other stimuli early after infection. A SINV mutant defective in host macromolecular synthesis shutoff induced IFN-alpha/beta in the MEF cultures dependent upon the activities of the TBK1 IRF3 activating kinase and host pattern recognition receptors (PRRs) PKR and MDA5 but not RIG-I. These results suggest that wild-type alphaviruses antagonize IFN induction after IRF3 activation but also may avoid detection by host PRRs early after infection.

  8. Genetic background and environmental conditions drive metabolic variation in wild type and transgenic soybean (Glycine max) seeds.

    PubMed

    Cohen, Hagai; Shir, Ofer M; Yu, Yang; Hou, Wensheng; Sun, Shi; Han, Tianfu; Amir, Rachel

    2016-08-01

    The metabolic profiles and composition of storage reserves of agricultural crop seeds are strongly regulated by heritable and environmental factors. Yet, very little is known about the genetic and environmental determinants of adaptive metabolic variation amongst wild type as well as transgenic seed populations derived from the same genetic background, grown under natural field conditions. The goal of the current study was to investigate the effects of natural environmental conditions on wild type and transgenic soybean seeds expressing a feedback-insensitive form of cystathionine γ-synthase, a methionine main regulatory enzyme. The seeds were grown in four geographically distinct habitats in China and then assayed for primary metabolic profiles using gas chromatography mass spectrometry, morphological traits and storage reserve accumulation. The analyses revealed changes in the levels of primary metabolites which evidently exhibited high correlation to methionine regardless of changes in environmental conditions. The environment, however, constituted a major determinant of metabolic profiles amongst seeds, as much more metabolites were observed to be affected by this variable, particularly along the north-to-south latitudinal gradient. The observations suggest that metabolic variation amongst seeds grown under natural field conditions depends upon the complex relationships existing amongst their genetic background and the environmental conditions characterizing their cultivation areas. PMID:27038216

  9. BclxL Changes Conformation upon Binding to Wild-type but Not Mutant p53 DNA Binding Domain*

    PubMed Central

    Hagn, Franz; Klein, Christian; Demmer, Oliver; Marchenko, Natasha; Vaseva, Angelina; Moll, Ute M.; Kessler, Horst

    2010-01-01

    p53 can induce apoptosis through mitochondrial membrane permeabilization by interaction of its DNA binding region with the anti-apoptotic proteins BclxL and Bcl2. However, little is known about the action of p53 at the mitochondria in molecular detail. By using NMR spectroscopy and fluorescence polarization we characterized the binding of wild-type and mutant p53 DNA binding domains to BclxL and show that the wild-type p53 DNA binding domain leads to structural changes in the BH3 binding region of BclxL, whereas mutants fail to induce such effects due to reduced affinity. This was probed by induced chemical shift and residual dipolar coupling data. These data imply that p53 partly achieves its pro-apoptotic function at the mitochondria by facilitating interaction between BclxL and BH3-only proteins in an allosteric mode of action. Furthermore, we characterize for the first time the binding behavior of Pifithrin-μ, a specific small molecule inhibitor of the p53-BclxL interaction, and present a structural model of the protein-ligand complex. A rather unusual behavior is revealed whereby Pifithrin-μ binds to both sides of the protein-protein complex. These data should facilitate the rational design of more potent specific BclxL-p53 inhibitors. PMID:19955567

  10. Gene Expression Analysis Indicates Divergent Mechanisms in DEN-Induced Carcinogenesis in Wild Type and Bid-Deficient Livers.

    PubMed

    Yu, Changshun; Yan, Shengmin; Khambu, Bilon; Chen, Xiaoyun; Dong, Zheng; Luo, Jianhua; Michalopoulos, George K; Wu, Shangwei; Yin, Xiao-Ming

    2016-01-01

    Bid is a Bcl-2 family protein. In addition to its pro-apoptosis function, Bid can also promote cell proliferation, maintain S phase checkpoint, and facilitate inflammasome activation. Bid plays important roles in tissue injury and regeneration, hematopoietic homeostasis, and tumorigenesis. Bid participates in hepatic carcinogenesis but the mechanism is not fully understood. Deletion of Bid resulted in diminished tumor burden and delayed tumor progression in a liver cancer model. In order to better understand the Bid-regulated events during hepatic carcinogenesis we performed gene expression analysis in wild type and bid-deficient mice treated with a hepatic carcinogen, diethylnitrosamine. We found that deletion of Bid caused significantly fewer alterations in gene expression in terms of the number of genes affected and the number of pathways affected. In addition, the expression profiles were remarkably different. In the wild type mice, there was a significant increase in the expression of growth regulation-related and immune/inflammation response-related genes, and a significant decrease in the expression of metabolism-related genes, both of which were diminished in bid-deficient livers. These data suggest that Bid could promote hepatic carcinogenesis via growth control and inflammation-mediated events. PMID:27196317

  11. Gene Expression Analysis Indicates Divergent Mechanisms in DEN-Induced Carcinogenesis in Wild Type and Bid-Deficient Livers

    PubMed Central

    Yu, Changshun; Yan, Shengmin; Khambu, Bilon; Chen, Xiaoyun; Dong, Zheng; Luo, Jianhua; Michalopoulos, George K.; Wu, Shangwei; Yin, Xiao-Ming

    2016-01-01

    Bid is a Bcl-2 family protein. In addition to its pro-apoptosis function, Bid can also promote cell proliferation, maintain S phase checkpoint, and facilitate inflammasome activation. Bid plays important roles in tissue injury and regeneration, hematopoietic homeostasis, and tumorigenesis. Bid participates in hepatic carcinogenesis but the mechanism is not fully understood. Deletion of Bid resulted in diminished tumor burden and delayed tumor progression in a liver cancer model. In order to better understand the Bid-regulated events during hepatic carcinogenesis we performed gene expression analysis in wild type and bid-deficient mice treated with a hepatic carcinogen, diethylnitrosamine. We found that deletion of Bid caused significantly fewer alterations in gene expression in terms of the number of genes affected and the number of pathways affected. In addition, the expression profiles were remarkably different. In the wild type mice, there was a significant increase in the expression of growth regulation-related and immune/inflammation response-related genes, and a significant decrease in the expression of metabolism-related genes, both of which were diminished in bid-deficient livers. These data suggest that Bid could promote hepatic carcinogenesis via growth control and inflammation-mediated events. PMID:27196317

  12. A recombinant measles vaccine virus expressing wild-type glycoproteins: consequences for viral spread and cell tropism.

    PubMed

    Johnston, I C; ter Meulen, V; Schneider-Schaulies, J; Schneider-Schaulies, S

    1999-08-01

    Wild-type, lymphotropic strains of measles virus (MV) and tissue culture-adapted MV vaccine strains possess different cell tropisms. This observation has led to attempts to identify the viral receptors and to characterize the functions of the MV glycoproteins. We have functionally analyzed the interactions of MV hemagglutinin (H) and fusion (F) proteins of vaccine (Edmonston) and wild-type (WTF) strains in different combinations in transfected cells. Cell-cell fusion occurs when both Edmonston F and H proteins are expressed in HeLa or Vero cells. The expression of WTF glycoproteins in HeLa cells did not result in syncytia, yet they fused efficiently with cells of lymphocytic origin. To further investigate the role of the MV glycoproteins in virus cell entry and also the role of other viral proteins in cell tropism, we generated recombinant vaccine MVs containing one or both glycoproteins from WTF. These viruses were viable and grew similarly in lymphocytic cells. Recombinant viruses expressing the WTFH protein showed a restricted spread in HeLa cells but spread efficiently in Vero cells. Parental WTF remained restricted in both cell types. Therefore, not only differential receptor usage but also other cell-specific factors are important in determining MV cell tropism. PMID:10400788

  13. Utilization of Whole-Cell MALDI-TOF Mass Spectrometry to Differentiate Burkholderia pseudomallei Wild-Type and Constructed Mutants

    PubMed Central

    Jaresitthikunchai, Janthima; Roytrakul, Sittiruk; Tungpradabkul, Sumalee

    2015-01-01

    Whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (whole-cell MALDI-TOF MS) has been widely adopted as a useful technology in the identification and typing of microorganisms. This study employed the whole-cell MALDI-TOF MS to identify and differentiate wild-type and mutants containing constructed single gene mutations of Burkholderia pseudomallei, a pathogenic bacterium causing melioidosis disease in both humans and animals. Candidate biomarkers for the B. pseudomallei mutants, including rpoS, ppk, and bpsI isolates, were determined. Taxon-specific and clinical isolate-specific biomarkers of B. pseudomallei were consistently found and conserved across all average mass spectra. Cluster analysis of MALDI spectra of all isolates exhibited separate distribution. A total of twelve potential mass peaks discriminating between wild-type and mutant isolates were identified using ClinProTools analysis. Two peaks (m/z 2721 and 2748 Da) were specific for the rpoS isolate, three (m/z 3150, 3378, and 7994 Da) for ppk, and seven (m/z 3420, 3520, 3587, 3688, 4623, 4708, and 5450 Da) for bpsI. Our findings demonstrated that the rapid, accurate, and reproducible mass profiling technology could have new implications in laboratory-based rapid differentiation of extensive libraries of genetically altered bacteria. PMID:26656930

  14. BclxL changes conformation upon binding to wild-type but not mutant p53 DNA binding domain.

    PubMed

    Hagn, Franz; Klein, Christian; Demmer, Oliver; Marchenko, Natasha; Vaseva, Angelina; Moll, Ute M; Kessler, Horst

    2010-01-29

    p53 can induce apoptosis through mitochondrial membrane permeabilization by interaction of its DNA binding region with the anti-apoptotic proteins BclxL and Bcl2. However, little is known about the action of p53 at the mitochondria in molecular detail. By using NMR spectroscopy and fluorescence polarization we characterized the binding of wild-type and mutant p53 DNA binding domains to BclxL and show that the wild-type p53 DNA binding domain leads to structural changes in the BH3 binding region of BclxL, whereas mutants fail to induce such effects due to reduced affinity. This was probed by induced chemical shift and residual dipolar coupling data. These data imply that p53 partly achieves its pro-apoptotic function at the mitochondria by facilitating interaction between BclxL and BH3-only proteins in an allosteric mode of action. Furthermore, we characterize for the first time the binding behavior of Pifithrin-mu, a specific small molecule inhibitor of the p53-BclxL interaction, and present a structural model of the protein-ligand complex. A rather unusual behavior is revealed whereby Pifithrin-mu binds to both sides of the protein-protein complex. These data should facilitate the rational design of more potent specific BclxL-p53 inhibitors. PMID:19955567

  15. Ablation of the Locus Coeruleus Increases Oxidative Stress in Tg-2576 Transgenic but Not Wild-Type Mice

    PubMed Central

    Hurko, Orest; Boudonck, Kurt; Gonzales, Cathleen; Hughes, Zoe A.; Jacobsen, J. Steve; Reinhart, Peter H.; Crowther, Daniel

    2010-01-01

    Mice transgenic for production of excessive or mutant forms of beta-amyloid differ from patients with Alzheimer's disease in the degree of inflammation, oxidative damage, and alteration of intermediary metabolism, as well as the paucity or absence of neuronal atrophy and cognitive impairment. Previous observers have suggested that differences in inflammatory response reflect a discrepancy in the state of the locus coeruleus (LC), loss of which is an early change in Alzheimer's disease but which is preserved in the transgenic mice. In this paper, we extend these observations by examining the effects of the LC on markers of oxidative stress and intermediary metabolism. We compare four groups: wild-type or Tg2576 Aβ transgenic mice injected with DSP4 or vehicle. Of greatest interest were metabolites different between ablated and intact transgenics, but not between ablated and intact wild-type animals. The Tg2576_DSP4 mice were distinguished from the other three groups by oxidative stress and altered energy metabolism. These observations provide further support for the hypothesis that Tg2576 Aβ transgenic mice with this ablation may be a more congruent model of Alzheimer's disease than are transgenics with an intact LC. PMID:20981353

  16. Bronze-2 gene of maize: reconstruction of a wild-type allele and analysis of transcription and splicing.

    PubMed Central

    Nash, J; Luehrsen, K R; Walbot, V

    1990-01-01

    The maize Bronze-2 (Bz2) gene, whose product acts late in the anthocyanin biosynthetic pathway, has been cloned and its transcript has been mapped. We have developed a general procedure for reconstructing wild-type alleles from transposable element-induced mutants. An existing transposon-containing clone, bz2::mu1 [McLaughlin, M., and Walbot, V. (1987). Genetics 117, 771-776], was modified by replacing the region of bz2::mu1 containing the transposon with the corresponding polymerase chain reaction-amplified sequence from the progenitor allele that has no Mu insertion. Particle gun delivery of the reconstructed Bz2 gene to embryonic scutellar tissue lacking a functional Bz2 gene complemented the bz2 mutant phenotype, as demonstrated by the production of purple spots. Having cloned the wild-type allele, we then analyzed the Bz2 transcript, whose features include an 82-nucleotide 5'-untranslated leader, one small intron (78 base pairs) within the coding region, and multiple polyadenylation sites. Four Mutator transposon insertions that eliminate gene function were mapped within the 850-nucleotide transcription unit. We found that variable levels of unspliced Bz2 RNA are present in purple husk tissue; this finding may indicate that the expression of Bz2 is regulated in part at the level of transcript processing. PMID:1967051

  17. Resistance to cadmium ions and formation of a cadmium-binding complex in various wild-type yeasts.

    PubMed

    Inouhe, M; Sumiyoshi, M; Tohoyama, H; Joho, M

    1996-04-01

    The resistance to cadmium ions (Cd-resistance) and possible formation of cadmium-binding complexes were examined in eight different wild-type yeasts. Saccharomyces exiguus, Pichia farinosa, Torulaspora delbrueckii and Schizosaccharomyces octosporus exhibited partial Cd-resistance, as compared to the Cd-resistant strain 301N and the Cu-resistant but Cd-sensitive strain X2180-1B of Saccharomyces cerevisiae. Saccharomyces carlsbergensis, Pichia mogii, Zygosaccharomyces rouxii and Kluyveromyces lactis were all Cd-sensitive. The partially Cd-sensitive species, with the exception of S. exiguus, accumulated Cd2+ ions in the cytoplasmic fraction to varying extents. This fraction from S. octosporus included a Cd-binding complex that contained (gamma EC)nG peptides known as cadystins or phytochelatins, while P. farinosa and T. delbrueckii synthesized Cd-binding proteins that were similar to the Cd-metallothionein produced by S. cerevisiae 301N in terms of molecular weight and amino acid composition. These results suggest that such cytoplasmic molecules play a role in the Cd-tolerance of the above three species of yeast. S. exiguus retained most cadmium in the cell wall fraction and no Cd-binding complex was found in the cytoplasm, an indication of the important role of the cell wall in its Cd-tolerance. Different modes of binding of Cd2+ ions appear to be involved in the Cd-resistance of wild-type yeasts and fungi. PMID:8673342

  18. Permissiveness of Human Cancer Cells to Oncolytic Bovine Herpesvirus 1 Is Mediated in Part by KRAS Activity

    PubMed Central

    Cuddington, Breanne P.

    2014-01-01

    ABSTRACT Oncolytic viruses (OVs) are attractive avenues of cancer therapy due to the absence of toxic side effects often seen with current treatment modalities. Bovine herpesvirus 1 (BHV-1) is a species-specific virus that does not induce cytotoxicity in normal primary human cells but can infect and kill various human immortalized and transformed cell lines. To gain a better understanding of the oncolytic breadth of BHV-1, the NCI panel of established human tumor cell lines was screened for sensitivity to the virus. Overall, 72% of the panel is permissive to BHV-1 infection, with corresponding decreases in cellular viability. This sensitivity is in comparison to a sensitivity of only 32% for a herpes simplex virus 1 (HSV-1)-based oncolytic vector. Strikingly, while 35% of the panel supports minimal or no BHV-1 replication, significant decreases in cellular viability still occur. These data suggest that BHV-1 is an OV with tropism for multiple tumor types and is able to induce cytotoxicity independent of significant virus replication. In contrast to other species-specific OVs, cellular sensitivity to BHV-1 does not correlate with type I interferon (IFN) signaling; however, mutations in KRAS were found to correlate with high levels of virus replication. The knockdown or overexpression of KRAS in human tumor cell lines yields modest changes in viral titers; however, overexpression of KRAS in normal primary cells elicits permissivity to BHV-1 infection. Together, these data suggest that BHV-1 is a broad-spectrum OV with a distinct mechanism of tumor targeting. IMPORTANCE Cancer remains a significant health issue, and novel treatments are required, particularly for tumors that are refractory to conventional therapies. Oncolytic viruses are a novel platform given their ability to specifically target tumor cells while leaving healthy cells intact. For this strategy to be successful, a fundamental understanding of virus-host interactions is required. We previously

  19. Targeting Mutant KRAS for Anticancer Therapeutics: A Review of Novel Small Molecule Modulators

    PubMed Central

    Wang, Yuanxiang; Kaiser, Christine E.; Frett, Brendan; Li, Hong-yu

    2015-01-01

    The RAS proteins play a role in cell differentiation, proliferation, and survival. Aberrant RAS signaling has been found to play a role in 30% of all cancers. KRAS, a key member of the RAS protein family, is an attractive cancer target, as frequent point mutations in the KRAS gene render the protein constitutively active. A number of attempts have been made to target aberrant KRAS signaling by identifying small molecule compounds that (1) are synthetic lethal to mutant KRAS, (2) block KRAS/GEF interactions, (3) inhibit downstream KRAS effectors, or (4) inhibit the post-translational processing of RAS proteins. In addition, inhibition of novel targets outside the main KRAS signaling pathway, specifically the cell cycle related kinase PLK1, has been shown have an effect in cells that harb