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Sample records for inhibition sensitizes tumor

  1. Hepatocyte growth factor sensitizes brain tumors to c-MET kinase inhibition

    PubMed Central

    Zhang, Ying; Farenholtz, Kaitlyn E.; Yang, Yanzhi; Guessous, Fadila; diPierro, Charles G.; Calvert, Valerie S.; Deng, Jianghong; Schiff, David; Xin, Wenjun; Lee, Jae K.; Purow, Benjamin; Christensen, James; Petricoin, Emanuel; Abounader, Roger

    2013-01-01

    Purpose The receptor tyrosine kinase (RTK) c-MET and its ligand hepatocyte growth factor (HGF) are deregulated and promote malignancy in cancer and brain tumors. Consequently, clinically applicable c-MET inhibitors have been developed. The purpose of this study was to investigate the not well known molecular determinants that predict responsiveness to c-MET inhibitors, and to explore new strategies for improving inhibitor efficacy in brain tumors. Experimental design We investigated the molecular factors and pathway activation signatures that determine sensitivity to c-MET inhibitors in a panel of glioblastoma and medulloblastoma cells, glioblastoma stem cells (GSCs), and established cell line-derived xenografts using functional assays, reverse protein microarrays, and in vivo tumor volume measurements, but validation with animal survival analyses remains to be done. We also explored new approaches for improving the efficacy of the inhibitors in vitro and in vivo. Results We found that HGF co-expression is a key predictor of response to c-MET inhibition among the examined factors, and identified an ERK/JAK/p53 pathway activation signature that differentiates c-MET inhibition in responsive and non-responsive cells. Surprisingly, we also found that short pre-treatment of cells and tumors with exogenous HGF moderately but statistically significantly enhanced the anti-tumor effects of c-MET inhibition. We observed a similar ligand-induced sensitization effect to an EGFR small molecule kinase inhibitor. Conclusions These findings allow the identification of a subset of patients that will be responsive to c-MET inhibition, and propose ligand pre-treatment as a potential new strategy for improving the anti-cancer efficacy of RTK inhibitors. PMID:23386689

  2. Recombinant TIMP-1-GPI inhibits growth of fibrosarcoma and enhances tumor sensitivity to doxorubicin.

    PubMed

    Bao, Q; Niess, H; Djafarzadeh, R; Zhao, Y; Schwarz, B; Angele, M K; Jauch, K-W; Nelson, P J; Bruns, C J

    2014-09-01

    Fibrosarcomas show a high incidence of recurrence and general resistance to apoptosis. Limiting tumor regrowth and increasing their sensitivity to chemotherapy and apoptosis represent key issues in developing more effective treatments of these tumors. Tissue inhibitor of metalloproteinase 1 (TIMP-1) broadly blocks matrix metalloproteinase (MMP) activity and can moderate tumor growth and metastasis. We previously described generation of a recombinant fusion protein linking TIMP-1 to glycosylphophatidylinositol (GPI) anchor (TIMP-1-GPI) that efficiently directs the inhibitor to cell surfaces. In the present report, we examined the effect of TIMP-1-GPI treatment on fibrosarcoma biology. Exogenously applied TIMP-1-GPI efficiently incorporated into surface membranes of human HT1080 fibrosarcoma cells. It inhibited their proliferation, migration, suppressed cancer cell clone formation, and enhanced apoptosis. Doxorubicin, the standard chemotherapeutic drug for fibrosarcoma, was tested alone or in combination with TIMP-1-GPI. In parallel, the influence of treatment on HT1080 side population cells (exhibiting tumor stem cell-like characteristics) was investigated using Hoechst 33342 staining. The sequential combination of TIMP-1-GPI and doxorubicin showed more than additive effects on apoptosis, while TIMP-1-GPI treatment alone effectively decreased "stem-cell like" side population cells of HT1080. TIMP-1-GPI treatment was validated using HT1080 fibrosarcoma murine xenografts. Growing tumors treated with repeated local injections of TIMP-1-GPI showed dramatically inhibited fibrosarcoma growth and reduced angiogenesis. Intraoperative peritumoral application of GPI-anchored TIMP-1 as an adjuvant to surgery may help maintain tumor control by targeting microscopic residual fibrosarcoma cells and increasing their sensitivity to chemotherapy.

  3. The downregulation of Mcl-1 via USP9X inhibition sensitizes solid tumors to Bcl-xl inhibition

    PubMed Central

    2012-01-01

    Background It has been shown in many solid tumors that the overexpression of the pro-survival Bcl-2 family members Bcl-xL and Mcl-1 confers resistance to a variety of chemotherapeutic agents. Mcl-1 is a critical survival protein in a variety of cell lineages and is critically regulated via ubiquitination. Methods The Mcl-1, Bcl-xL and USP9X expression patterns in human lung and colon adenocarcinomas were evaluated via immunohistochemistry. Interaction between USP9X and Mcl-1 was demonstrated by immunoprecipitation-western blotting. The protein expression profiles of Mcl-1, Bcl-xL and USP9X in multiple cancer cell lines were determined by western blotting. Annexin-V staining and cleaved PARP western blotting were used to assay for apoptosis. The cellular toxicities after various treatments were measured via the XTT assay. Results In our current analysis of colon and lung cancer samples, we demonstrate that Mcl-1 and Bcl-xL are overexpressed and also co-exist in many tumors and that the expression levels of both genes correlate with the clinical staging. The downregulation of Mcl-1 or Bcl-xL via RNAi was found to increase the sensitivity of the tumor cells to chemotherapy. Furthermore, our analyses revealed that USP9X expression correlates with that of Mcl-1 in human cancer tissue samples. We additionally found that the USP9X inhibitor WP1130 promotes Mcl-1 degradation and increases tumor cell sensitivity to chemotherapies. Moreover, the combination of WP1130 and ABT-737, a well-documented Bcl-xL inhibitor, demonstrated a chemotherapeutic synergy and promoted apoptosis in different tumor cells. Conclusion Mcl-1, Bcl-xL and USP9X overexpression are tumor survival mechanisms protective against chemotherapy. USP9X inhibition increases tumor cell sensitivity to various chemotherapeutic agents including Bcl-2/Bcl-xL inhibitors. PMID:23171055

  4. Multi-targeted inhibition of tumor growth and lung metastasis by redox-sensitive shell crosslinked micelles loading disulfiram

    NASA Astrophysics Data System (ADS)

    Duan, Xiaopin; Xiao, Jisheng; Yin, Qi; Zhang, Zhiwen; Yu, Haijun; Mao, Shirui; Li, Yaping

    2014-03-01

    Metastasis, the main cause of cancer related deaths, remains the greatest challenge in cancer treatment. Disulfiram (DSF), which has multi-targeted anti-tumor activity, was encapsulated into redox-sensitive shell crosslinked micelles to achieve intracellular targeted delivery and finally inhibit tumor growth and metastasis. The crosslinked micelles demonstrated good stability in circulation and specifically released DSF under a reductive environment that mimicked the intracellular conditions of tumor cells. As a result, the DSF-loaded redox-sensitive shell crosslinked micelles (DCMs) dramatically inhibited cell proliferation, induced cell apoptosis and suppressed cell invasion, as well as impairing tube formation of HMEC-1 cells. In addition, the DCMs could accumulate in tumor tissue and stay there for a long time, thereby causing significant inhibition of 4T1 tumor growth and marked prevention in lung metastasis of 4T1 tumors. These results suggested that DCMs could be a promising delivery system in inhibiting the growth and metastasis of breast cancer.

  5. EZH2 inhibition sensitizes BRG1 and EGFR mutant lung tumors to TopoII inhibitors

    PubMed Central

    Fillmore, Christine M.; Xu, Chunxiao; Desai, Pooja T.; Berry, Joanne M.; Rowbotham, Samuel P.; Lin, Yi-Jang; Zhang, Haikuo; Marquez, Victor E.; Hammerman, Peter S.; Wong, Kwok-Kin; Kim, Carla F.

    2014-01-01

    SUMMARY Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide1. Chemotherapies such as the topoisomerase II inhibitor (TopoIIi) etoposide effectively reduce disease in a minority of NSCLC patients2,3; therefore, alternative drug targets, including epigenetic enzymes, are under consideration for therapeutic intervention4. A promising potential epigenetic target is the methyltransferase EZH2, which in the context of the Polycomb Repressive Complex 2 (PRC2) is well known to tri-methylate Histone H3 at lysine 27 (H3K27me3) and elicit gene silencing5. Here, we demonstrate that EZH2 inhibition (EZH2i) had differential effects on TopoIIi response of NSCLCs in vitro and in vivo. EGFR and BRG1 mutations were genetic biomarkers that predicted enhanced sensitivity to TopoIIi in response to EZH2i. BRG1 loss-of-function mutant tumors responded to EZH2i with increased S phase, anaphase bridging, apoptosis, and TopoIIi sensitivity. Conversely, EGFR and BRG1 wild-type tumors up-regulated BRG1 in response to EZH2i and ultimately became more resistant to TopoIIi. EGFR gain-of-function mutant tumors were also sensitive to dual EZH2i and TopoIIi, due to genetic antagonism between EGFR and BRG1. These findings suggest an exciting opportunity for precision medicine in the genetically complex disease of NSCLC. PMID:25629630

  6. Pit-1 inhibits BRCA1 and sensitizes human breast tumors to cisplatin and vitamin D treatment

    PubMed Central

    Seoane, Samuel; Arias, Efigenia; Sigueiro, Rita; Sendon-Lago, Juan; Martinez-Ordoñez, Anxo; Castelao, Esteban; Eiró, Noemí; Garcia-Caballero, Tomás; Macia, Manuel; Lopez-Lopez, Rafael; Maestro, Miguel; Vizoso, Francisco; Mouriño, Antonio; Perez-Fernandez, Roman

    2015-01-01

    The POU class 1 homeobox 1 (POU1F1, also known as Pit-1), pertaining to the Pit-Oct-Unc (POU) family of transcription factors, has been related to tumor growth and metastasis in breast. However, its role in response to breast cancer therapy is unknown. We found that Pit-1 down-regulated DNA-damage and repair genes, and specifically inhibited BRCA1 gene expression, sensitizing breast cancer cells to DNA-damage agents. Administration of 1α, 25-dihydroxy-3-epi-vitamin D3 (3-Epi, an endogenous low calcemic vitamin D metabolite) reduced Pit-1 expression, and synergized with cisplatin, thus, decreasing cell proliferation and apoptosis in vitro, and reducing tumor growth in vivo. In addition, fifteen primary cultures of human breast tumors showed significantly decreased proliferation when treated with 3-Epi+cisplatin, compared to cisplatin alone. This response positively correlated with Pit-1 levels. Our findings demonstrate that high levels of Pit-1 and reduced BRCA1 levels increase breast cancer cell susceptibility to 3-Epi+cisplatin therapy. PMID:25992773

  7. Inhibition of Galectin-1 Sensitizes HRAS-driven Tumor Growth to Rapamycin Treatment.

    PubMed

    Michael, James V; Wurtzel, Jeremy G T; Goldfinger, Lawrence E

    2016-10-01

    The goal of this study was to develop combinatorial application of two drugs currently either in active use as anticancer agents (rapamycin) or in clinical trials (OTX008) as a novel strategy to inhibit Harvey RAS (HRAS)-driven tumor progression. HRAS anchored to the plasma membrane shuttles from the lipid ordered (Lo) domain to the lipid ordered/lipid disordered border upon activation, and retention of HRAS at these sites requires galectin-1. We recently showed that genetically enforced Lo sequestration of HRAS inhibited mitogen-activated protein kinase (MAPK) signaling, but not phoshatidylinositol 3-kinase (PI3K) activation. Here we show that inhibition of galectin-1 with OTX008 sequestered HRAS in the Lo domain, blocked HRAS-mediated MAPK signaling, and attenuated HRAS-driven tumor progression in mice. HRAS-driven tumor growth was also attenuated by treatment with mammalian target of rapamycin (mTOR) inhibitor rapamycin, and this effect was further enhanced in tumors driven by Lo-sequestered HRAS. These drugs also revealed bidirectional cross-talk in HRAS pathways. Moreover, dual pathway inhibition with OTX008 and rapamycin resulted in nearly complete ablation of HRAS-driven tumor growth. These findings indicate that membrane microdomain sequestration of HRAS with galectin-1 inhibition, coupled with mTOR inhibition, may support a novel therapeutic approach to treat HRAS-mutant cancer.

  8. Inhibition of DNA methylation promotes breast tumor sensitivity to netrin-1 interference.

    PubMed

    Grandin, Mélodie; Mathot, Pauline; Devailly, Guillaume; Bidet, Yannick; Ghantous, Akram; Favrot, Clementine; Gibert, Benjamin; Gadot, Nicolas; Puisieux, Isabelle; Herceg, Zdenko; Delcros, Jean-Guy; Bernet, Agnès; Mehlen, Patrick; Dante, Robert

    2016-08-01

    In a number of human cancers, NTN1 upregulation inhibits apoptosis induced by its so-called dependence receptors DCC and UNC5H, thus promoting tumor progression. In other cancers however, the selective inhibition of this dependence receptor death pathway relies on the silencing of pro-apoptotic effector proteins. We show here that a substantial fraction of human breast tumors exhibits simultaneous DNA methylation-dependent loss of expression of NTN1 and of DAPK1, a serine threonine kinase known to transduce the netrin-1 dependence receptor pro-apoptotic pathway. The inhibition of DNA methylation by drugs such as decitabine restores the expression of both NTN1 and DAPK1 in netrin-1-low cancer cells. Furthermore, a combination of decitabine with NTN1 silencing strategies or with an anti-netrin-1 neutralizing antibody potentiates tumor cell death and efficiently blocks tumor growth in different animal models. Thus, combining DNA methylation inhibitors with netrin-1 neutralizing agents may be a valuable strategy for combating cancer. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

  9. Akt inhibition promotes autophagy and sensitizes PTEN-null tumors to lysosomotropic agents

    PubMed Central

    Degtyarev, Michael; De Mazière, Ann; Orr, Christine; Lin, Jie; Lee, Brian B.; Tien, Janet Y.; Prior, Wei W.; van Dijk, Suzanne; Wu, Hong; Gray, Daniel C.; Davis, David P.; Stern, Howard M.; Murray, Lesley J.; Hoeflich, Klaus P.; Klumperman, Judith; Friedman, Lori S.; Lin, Kui

    2008-01-01

    Although Akt is known as a survival kinase, inhibitors of the phosphatidylinositol 3-kinase (PI3K)–Akt pathway do not always induce substantial apoptosis. We show that silencing Akt1 alone, or any combination of Akt isoforms, can suppress the growth of tumors established from phosphatase and tensin homologue–null human cancer cells. Although these findings indicate that Akt is essential for tumor maintenance, most tumors eventually rebound. Akt knockdown or inactivation with small molecule inhibitors did not induce significant apoptosis but rather markedly increased autophagy. Further treatment with the lysosomotropic agent chloroquine caused accumulation of abnormal autophagolysosomes and reactive oxygen species, leading to accelerated cell death in vitro and complete tumor remission in vivo. Cell death was also promoted when Akt inhibition was combined with the vacuolar H+–adenosine triphosphatase inhibitor bafilomycin A1 or with cathepsin inhibition. These results suggest that blocking lysosomal degradation can be detrimental to cancer cell survival when autophagy is activated, providing rationale for a new therapeutic approach to enhancing the anticancer efficacy of PI3K–Akt pathway inhibition. PMID:18838554

  10. Suppression of homologous recombination sensitizes human tumor cells to IGF-1R inhibition.

    PubMed

    Lodhia, Kunal A; Gao, Shan; Aleksic, Tamara; Esashi, Fumiko; Macaulay, Valentine M

    2015-06-15

    Inhibition of type 1 IGF receptor (IGF-1R) sensitizes to DNA-damaging cancer treatments, and delays repair of DNA double strand breaks (DSBs) by non-homologous end-joining and homologous recombination (HR). In a recent screen for mediators of resistance to IGF-1R inhibitor AZ12253801, we identified RAD51, required for the strand invasion step of HR. These findings prompted us to test the hypothesis that IGF-1R-inhibited cells accumulate DSBs formed at endogenous DNA lesions, and depend on residual HR for their repair. Indeed, initial experiments showed time-dependent accumulation of γH2AX foci in IGF-1R -inhibited or -depleted prostate cancer cells. We then tested effects of suppressing HR, and found that RAD51 depletion enhanced AZ12253801 sensitivity in PTEN wild-type prostate cancer cells but not in cells lacking functional PTEN. Similar sensitization was induced in prostate cancer cells by depletion of BRCA2, required for RAD51 loading onto DNA, and in BRCA2(-/-) colorectal cancer cells, compared with isogenic BRCA2(+/-) cells. We also assessed chemical HR inhibitors, finding that RAD51 inhibitor BO2 blocked RAD51 focus formation and sensitized to AZ12253801. Finally, we tested CDK1 inhibitor RO-3306, which impairs HR by inhibiting CDK1-mediated BRCA1 phosphorylation. R0-3306 suppressed RAD51 focus formation consistent with HR attenuation, and sensitized prostate cancer cells to IGF-1R inhibition, with 2.4-fold reduction in AZ12253801 GI50 and 13-fold reduction in GI80. These data suggest that responses to IGF-1R inhibition are enhanced by genetic and chemical approaches to suppress HR, defining a population of cancers (PTEN wild-type, BRCA mutant) that may be intrinsically sensitive to IGF-1R inhibitory drugs. © 2014 UICC.

  11. miR-103 inhibits proliferation and sensitizes hemopoietic tumor cells for glucocorticoid-induced apoptosis

    PubMed Central

    Biton, Moshe; Stepensky, Polina

    2017-01-01

    Glucocorticoid (GC) hormones are an important ingredient of leukemia therapy since they are potent inducers of lymphoid cell apoptosis. However, the development of GC resistance remains an obstacle in GC-based treatment. In the present investigation we found that miR-103 is upregulated in GC-sensitive leukemia cells treated by the hormone. Transfection of GC resistant cells with miR-103 sensitized them to GC induced apoptosis (GCIA), while miR-103 sponging of GC sensitive cells rendered them partially resistant. miR-103 reduced the expression of cyclin dependent kinase (CDK2) and its cyclin E1 target, thereby leading to inhibition of cellular proliferation. miR-103 is encoded within the fifth intron of PANK3 gene. We demonstrate that the GC receptor (GR) upregulates miR-103 by direct interaction with GC response element (GRE) in the PANK3 enhancer. Consequently, miR-103 targets the c-Myc activators c-Myb and DVL1, thereby reducing c-Myc expression. Since c-Myc is a transcription factor of the miR-17~92a poly-cistron, all six miRNAs of the latter are also downregulated. Of these, miR-18a and miR-20a are involved in GCIA, as they target GR and BIM, respectively. Consequently, GR and BIM expression are elevated, thus advancing GCIA. Altogether, this study highlights miR-103 as a useful prognostic biomarker and drug for leukemia management in the future. PMID:27888798

  12. Interleukin-4 receptor-targeted delivery of Bcl-xL siRNA sensitizes tumors to chemotherapy and inhibits tumor growth.

    PubMed

    Guruprasath, Padmanaban; Kim, Jihoon; Gunassekaran, Gowri Rangaswamy; Chi, Lianhua; Kim, Soyoun; Park, Rang-Woon; Kim, Sang-Hyun; Baek, Moon-Chang; Bae, Sang Mun; Kim, Sang-Yeob; Kim, Dong-Kyu; Park, In-Kyu; Kim, Won-Jong; Lee, Byungheon

    2017-10-01

    IL-4 receptor (IL-4R) is commonly up-regulated on tumor cells, and interactions between the receptor and Interleukin-4 (IL-4) can induce the expression of anti-apoptotic proteins, including Bcl-xL. This contributes to tumor cell survival and their resistance to chemotherapy. In this study, we exploited IL-4R-targeted delivery of Bcl-xL siRNA to IL-4R-expressing tumor cells in order to sensitize them to chemotherapy. To target IL-4R, an IL-4R-binding peptide, IL4RPep-1, was attached to branched polyethyleneimine-superparamagnetic iron oxide nanoparticles (BPEI-SPION). These nanoparticles were then complexed with Bcl-xL-targeting siRNA. IL-4R-targeted BPEI-SPION/Bcl-xL siRNA more efficiently reduced Bcl-xL gene expression and enhanced cytotoxicity of doxorubicin in MDA-MB231 breast tumor cells compared to untargeted BPEI-SPION/Bcl-xL siRNA. The siRNA was released from the complexes after 15 h of incubation at pH 5.5 and was stable in the complexes up to 72 h in the serum. The IL-4R-targeted BPEI-SPION/siRNA was internalized by cells through IL-4R, successfully escaped the endosomes, and was dispersed into the cytoplasm. Near-infrared fluorescence and magnetic resonance imaging demonstrated that in vivo tumor homing and accumulation of IL-4R-targeted BPEI-SPION/siRNA were both higher than untargeted BPEI-SPION/siRNA. The IL-4R-targeted BPEI-SPION/Bcl-xL siRNA, in combination with doxorubicin, significantly inhibited tumor growth in mice compared to untargeted BPEI-SPION/Bcl-xL siRNA. These results suggest that the IL-4R-targeted delivery of Bcl-xL siRNA to IL-4R-expressing tumors can sensitize tumors to chemotherapy and enhance the efficacy of anti-tumor therapeutics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Mechanism of Telomerase Inhibition Using a Small Inhibitory RNAs and Induction of Breast Tumor Cell Sensitization

    DTIC Science & Technology

    2007-04-01

    Other studies have attempted to target hTERT in a chronic fashion and inhibit telomerase using a variety of strategies including ribozymes , peptide...Hao, Z-M. et al. 2005. Intensive inhibition of hTERT expression by a ribozyme induces rapid apoptosis of cancer cells through a telomere length...limiting and necessary for telomerase function in vivo. Curr. Biol. 10: 1459-1462. Ludwig, A., et al. 2001. Ribozyme cleavage of telomerse mRNA

  14. Targeting MYCN IRES in MYCN-amplified neuroblastoma with miR-375 inhibits tumor growth and sensitizes tumor cells to radiation.

    PubMed

    Zhang, Hailong; Liu, Tao; Yi, Sha; Gu, Lubing; Zhou, Muxiang

    2015-08-01

    The MYCN oncogene is amplified in 20% of neuroblastomas, leading to its overexpression at both the mRNA and protein levels. MYCN overexpression is strongly associated with advanced disease stage, rapid tumor progression and a worse prognosis. In the present study, we identified microRNA-375 (miR-375) as a negative regulator of MYCN: enforced expression of miR-375 inhibited MYCN-amplified neuroblastoma in vitro and in vivo. Upon searching the website miRbase for possible miR-375 binding sites within the whole MYCN mRNA, we found that the MYCN 5'-UTR had significant sequence complementarity to miR-375, yet no complementary sequences existed within the MYCN 3'-UTR and coding regions. Enforced overexpression of miR-375 efficiently inhibited MYCN mRNA translation and protein synthesis, via an IRES-dependent mechanism. In athymic nude mouse model with human MYCN-amplified neuroblastoma, MYCN downregulation by miR-375 led to inhibition of tumor cell growth and tumorigenicity. In particular, miR-375-regulated inhibition of MYCN translation was enhanced when MYCN-amplified neuroblastoma cells were exposed to stress stimulation, such as ionizing irradiation (IR), resulting in a remarkable increase in the neuroblastoma's sensitivity to IR-induced cell death. Our results identified a novel mechanism by which IRES-dependent translation of MYCN is repressed by miR-375, particularly during cellular stress, highlighting a potential anticancer strategy: the development of miR-375 as a novel therapeutic agent to treat MYCN-amplified neuroblastoma. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  15. Whole-genome duplication increases tumor cell sensitivity to MPS1 inhibition

    PubMed Central

    Jemaà, Mohamed; Manic, Gwenola; Lledo, Gwendaline; Lissa, Delphine; Reynes, Christelle; Morin, Nathalie; Chibon, Frédéric; Sistigu, Antonella; Castedo, Maria; Vitale, Ilio; Kroemer, Guido; Abrieu, Ariane

    2016-01-01

    Several lines of evidence indicate that whole-genome duplication resulting in tetraploidy facilitates carcinogenesis by providing an intermediate and metastable state more prone to generate oncogenic aneuploidy. Here, we report a novel strategy to preferentially kill tetraploid cells based on the abrogation of the spindle assembly checkpoint (SAC) via the targeting of TTK protein kinase (better known as monopolar spindle 1, MPS1). The pharmacological inhibition as well as the knockdown of MPS1 kills more efficiently tetraploid cells than their diploid counterparts. By using time-lapse videomicroscopy, we show that tetraploid cells do not survive the aborted mitosis due to SAC abrogation upon MPS1 depletion. On the contrary diploid cells are able to survive up to at least two more cell cycles upon the same treatment. This effect might reflect the enhanced difficulty of cells with whole-genome doubling to tolerate a further increase in ploidy and/or an elevated level of chromosome instability in the absence of SAC functions. We further show that MPS1-inhibited tetraploid cells promote mitotic catastrophe executed by the intrinsic pathway of apoptosis, as indicated by the loss of mitochondrial potential, the release of the pro-apoptotic cytochrome c from mitochondria, and the activation of caspases. Altogether, our results suggest that MPS1 inhibition could be used as a therapeutic strategy for targeting tetraploid cancer cells. PMID:26637805

  16. Inhibition of Casein kinase-2 induces p53-dependent cell cycle arrest and sensitizes glioblastoma cells to tumor necrosis factor (TNFα)-induced apoptosis through SIRT1 inhibition.

    PubMed

    Dixit, D; Sharma, V; Ghosh, S; Mehta, V S; Sen, E

    2012-02-09

    Glioblastoma multiforme (GBM) are resistant to TNFα-induced apoptosis and blockade of TNFα-induced NF-κB activation sensitizes glioma cells to apoptosis. As Casein kinase-2 (CK2) induces aberrant NF-κB activation and as we observed elevated CK2 levels in GBM tumors, we investigated the potential of CK2 inhibitors (CK2-Is) - DRB and Apigenin in sensitizing glioma cells to TNFα-induced apoptosis. CK2-Is and CK2 small interfering RNA (siRNA) reduced glioma cell viability, inhibited TNFα-mediated NF-κB activation, and sensitized cell to TNFα-induced apoptosis. Importantly, CK2-Is activated p53 function in wild-type but not in p53 mutant cells. Activation of p53 function involved its increased transcriptional activation, DNA-binding ability, increased expression of p53 target genes associated with cell cycle progression and apoptosis. Moreover, CK2-Is decreased telomerase activity and increased senescence in a p53-dependent manner. Apoptotic gene profiling indicated that CK2-Is differentially affect p53 and TNFα targets in p53 wild-type and mutant glioma cells. CK2-I decreased MDM2-p53 association and p53 ubiquitination to enhance p53 levels. Interestingly, CK2-Is downregulated SIRT1 activity and over-expression of SIRT1 decreased p53 transcriptional activity and rescued cells from CK2-I-induced apoptosis. This ability of CK2-Is to sensitize glioma to TNFα-induced death via multiple mechanisms involving abrogation of NF-κB activation, reactivation of wild-type p53 function and SIRT1 inhibition warrants investigation.

  17. Inhibition of 4E-BP1 Sensitizes U87 Glioblastoma Xenograft Tumors to Irradiation by Decreasing Hypoxia Tolerance

    SciTech Connect

    Dubois, Ludwig; Magagnin, Michael G.; Cleven, Arjen H.G.; Weppler, Sherry A.; Grenacher, Beat; Landuyt, Willy; Lieuwes, Natasja; Lambin, Philippe; Gorr, Thomas A.; Koritzinsky, Marianne

    2009-03-15

    Purpose: Eukaryotic initiation factor 4E (eIF4E) is an essential rate-limiting factor for cap-dependent translation in eukaryotic cells. Elevated eIF4E activity is common in many human tumors and is associated with disease progression. The growth-promoting effects of eIF4E are in turn negatively regulated by 4E-BP1. However, although 4E-BP1 harbors anti-growth activity, its expression is paradoxically elevated in some tumors. The aim of this study was to investigate the functional role of 4E-BP1 in the context of solid tumors. Methods and Materials: In vitro and in vivo growth properties, hypoxia tolerance, and response to radiation were assessed for HeLa and U87 cells, after stable expression of shRNA specific for 4E-BP1. Results: We found that loss of 4E-BP1 expression did not significantly alter in vitro growth but did accelerate the growth of U87 tumor xenografts, consistent with the growth-promoting function of deregulated eIF4E. However, cells lacking 4E-BP1 were significantly more sensitive to hypoxia-induced cell death in vitro. Furthermore, 4E-BP1 knockdown cells produced tumors more sensitive to radiation because of a reduction in the viable fraction of radioresistant hypoxic cells. Decreased hypoxia tolerance in the 4E-BP1 knockdown tumors was evident by increased cleaved caspase-3 levels and was associated with a reduction in adenosine triphosphate (ATP). Conclusions: Our results suggest that although tumors often demonstrate increases in cap-dependent translation, regulation of this activity is required to facilitate energy conservation, hypoxia tolerance, and tumor radioresistance. Furthermore, we suggest that targeting translational control may be an effective way to target hypoxic cells and radioresistance in metabolically hyperactive tumors.

  18. Inhibition of c-Jun N-terminal kinase sensitizes tumor cells to flavonoid-induced apoptosis through down-regulation of JunD

    SciTech Connect

    Kook, Sung-Ho; Son, Young-Ok; Jang, Yong-Suk; Lee, Kyung-Yeol; Lee, Seung-Ah; Kim, Beom-Soo; Lee, Hyun-Jeong; Lee, Jeong-Chae

    2008-03-15

    Reduction of susceptibility to apoptosis signals is a crucial step in carcinogenesis. Therefore, sensitization of tumor cells to apoptosis is a promising therapeutic strategy. c-Jun NH{sub 2}-terminal kinase (JNK) has been implicated in stress-induced apoptosis. However, many studies also emphasize the role of JNK on cell survival, although its mechanisms are not completely understood. Previously, we found that inhibition of JNK activity promotes flavonoid-mediated apoptosis of human osteosarcoma cells. We thus determined whether inhibition of JNK sensitizes tumor cells to a bioflavonoid-induced apoptosis, and whether this effect of JNK is a general effect. As the results, quercetin and genistein as well as a flavonoid fraction induced apoptosis of tumor cells, which was further accelerated by specific JNK inhibitor, SP600125 or by small interfering RNA specific to JNK1/2. This effect was specific to types of cells because it was further apparent in tumorigenic cell lines. Inhibition of JNK by SP600125 also reduced flavonoid-stimulated nuclear induction of JunD which was known to have protective role in apoptosis, whereas JNK inhibition alone had little effect on apoptosis. The flavonoid-induced apoptosis of tumor cells was significantly enhanced by transfecting them with antisense JunD oligonucleotides. These results suggest that inhibition of JNK facilitates flavonoid-induced apoptosis through down-regulation of JunD, which is further sensitive to tumor cells. Therefore, combination with a specific JNK inhibitor further enhances the anti-cancer and chemopreventive potential of bio-flavonoids.

  19. Low levels of circulating estrogen sensitize PTEN-null endometrial tumors to poly (ADP-ribose) polymerase (PARP) inhibition in vivo

    PubMed Central

    Janzen, Deanna M.; Paik, Daniel Y.; Rosales, Miguel A.; Yep, Brian; Cheng, Donghui; Witte, Owen N.; Kayadibi, Huseyin; Ryan, Christopher M.; Jung, Michael E.; Faull, Kym; Memarzadeh, Sanaz

    2013-01-01

    Prior in vitro work demonstrated that PARP inhibition induces cell death in PTEN-null endometrial cancer cell lines, but the in vivo therapeutic efficacy of these agents against endometrial cancer remains unknown. Here we test the efficacy of AZD2281 (Olaparib), an oral PARP inhibitor, in therapy of PTEN-null endometrial tumors in a pre-clinical endometrial cancer mouse model. Primary endometrial tumors were generated by epithelial loss of PTEN using an in vivo model. This model recapitulates epithelial specific loss of PTEN seen in human tumors and histologically resembles endometrioid carcinomas, the predominant sub-type of human endometrial cancers. Olaparib was administered orally to tumor bearing mice in two hormonal extremes: high or low estrogen. Olaparib treatment achieved a significant reduction in tumor size in a low estrogenic milieu. In striking contrast, no response to Olaparib was seen in tumors exposed to high levels of estrogen. Two key observations were made when estrogen levels were dropped. Serum concentration of Olaparib was significantly increased resulting in sustained PARP inhibition at the tumor bed. The homologous recombination pathway was compromised evidenced by decreased Rad51 protein and function. These two mechanisms may account for the sensitization of PTEN-null tumors to Olaparib with estrogen deprivation. Results of this pre-clinical trial suggest that orally administered PARP inhibitors in a low estrogenic hormonal milieu can effectively target PTEN-null endometrial tumors. Extension of this work to clinical trials could personalize the therapy of women afflicted with advanced endometrial cancer using well tolerated orally administered therapeutic agents. PMID:24222661

  20. DMAPT inhibits NF-κB activity and increases sensitivity of prostate cancer cells to X-rays in vitro and in tumor xenografts in vivo.

    PubMed

    Mendonca, Marc S; Turchan, William T; Alpuche, Melanie E; Watson, Christopher N; Estabrook, Neil C; Chin-Sinex, Helen; Shapiro, Jeremy B; Imasuen-Williams, Imade E; Rangel, Gabriel; Gilley, David P; Huda, Nazmul; Crooks, Peter A; Shapiro, Ronald H

    2017-11-01

    Constitutive activation of the pro-survival transcription factor NF-κB has been associated with resistance to both chemotherapy and radiation therapy in many human cancers, including prostate cancer. Our lab and others have demonstrated that the natural product parthenolide can inhibit NF-κB activity and sensitize PC-3 prostate cancers cells to X-rays in vitro; however, parthenolide has poor bioavailability in vivo and therefore has little clinical utility in this regard. We show here that treatment of PC-3 and DU145 human prostate cancer cells with dimethylaminoparthenolide (DMAPT), a parthenolide derivative with increased bioavailability, inhibits constitutive and radiation-induced NF-κB binding activity and slows prostate cancer cell growth. We also show that DMAPT increases single and fractionated X-ray-induced killing of prostate cancer cells through inhibition of DNA double strand break repair and also that DMAPT-induced radiosensitization is, at least partially, dependent upon the alteration of intracellular thiol reduction-oxidation chemistry. Finally, we demonstrate that the treatment of PC-3 prostate tumor xenografts with oral DMAPT in addition to radiation therapy significantly decreases tumor growth and results in significantly smaller tumor volumes compared to xenografts treated with either DMAPT or radiation therapy alone, suggesting that DMAPT might have a potential clinical role as a radiosensitizing agent in the treatment of prostate cancer. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. NAMPT inhibition sensitizes pancreatic adenocarcinoma cells to tumor-selective, PAR-independent metabolic catastrophe and cell death induced by β-lapachone

    PubMed Central

    Moore, Z; Chakrabarti, G; Luo, X; Ali, A; Hu, Z; Fattah, F J; Vemireddy, R; DeBerardinis, R J; Brekken, R A; Boothman, D A

    2015-01-01

    Nicotinamide phosphoribosyltransferase (NAMPT) inhibitors (e.g., FK866) target the most active pathway of NAD+ synthesis in tumor cells, but lack tumor-selectivity for use as a single agent. Reducing NAD+ pools by inhibiting NAMPT primed pancreatic ductal adenocarcinoma (PDA) cells for poly(ADP ribose) polymerase (PARP1)-dependent cell death induced by the targeted cancer therapeutic, β-lapachone (β-lap, ARQ761), independent of poly(ADP ribose) (PAR) accumulation. β-Lap is bioactivated by NADPH:quinone oxidoreductase 1 (NQO1) in a futile redox cycle that consumes oxygen and generates high levels of reactive oxygen species (ROS) that cause extensive DNA damage and rapid PARP1-mediated NAD+ consumption. Synergy with FK866+β-lap was tumor-selective, only occurring in NQO1-overexpressing cancer cells, which is noted in a majority (∼85%) of PDA cases. This treatment strategy simultaneously decreases NAD+ synthesis while increasing NAD+ consumption, reducing required doses and treatment times for both drugs and increasing potency. These complementary mechanisms caused profound NAD(P)+ depletion and inhibited glycolysis, driving down adenosine triphosphate levels and preventing recovery normally observed with either agent alone. Cancer cells died through an ROS-induced, μ-calpain-mediated programmed cell death process that kills independent of caspase activation and is not driven by PAR accumulation, which we call NAD+-Keresis. Non-overlapping specificities of FK866 for PDA tumors that rely heavily on NAMPT-catalyzed NAD+ synthesis and β-lap for cancer cells with elevated NQO1 levels affords high tumor-selectivity. The concept of reducing NAD+ pools in cancer cells to sensitize them to ROS-mediated cell death by β-lap is a novel strategy with potential application for pancreatic and other types of NQO1+ solid tumors. PMID:25590809

  2. NAMPT inhibition sensitizes pancreatic adenocarcinoma cells to tumor-selective, PAR-independent metabolic catastrophe and cell death induced by β-lapachone.

    PubMed

    Moore, Z; Chakrabarti, G; Luo, X; Ali, A; Hu, Z; Fattah, F J; Vemireddy, R; DeBerardinis, R J; Brekken, R A; Boothman, D A

    2015-01-15

    Nicotinamide phosphoribosyltransferase (NAMPT) inhibitors (e.g., FK866) target the most active pathway of NAD(+) synthesis in tumor cells, but lack tumor-selectivity for use as a single agent. Reducing NAD(+) pools by inhibiting NAMPT primed pancreatic ductal adenocarcinoma (PDA) cells for poly(ADP ribose) polymerase (PARP1)-dependent cell death induced by the targeted cancer therapeutic, β-lapachone (β-lap, ARQ761), independent of poly(ADP ribose) (PAR) accumulation. β-Lap is bioactivated by NADPH:quinone oxidoreductase 1 (NQO1) in a futile redox cycle that consumes oxygen and generates high levels of reactive oxygen species (ROS) that cause extensive DNA damage and rapid PARP1-mediated NAD(+) consumption. Synergy with FK866+β-lap was tumor-selective, only occurring in NQO1-overexpressing cancer cells, which is noted in a majority (∼85%) of PDA cases. This treatment strategy simultaneously decreases NAD(+) synthesis while increasing NAD(+) consumption, reducing required doses and treatment times for both drugs and increasing potency. These complementary mechanisms caused profound NAD(P)(+) depletion and inhibited glycolysis, driving down adenosine triphosphate levels and preventing recovery normally observed with either agent alone. Cancer cells died through an ROS-induced, μ-calpain-mediated programmed cell death process that kills independent of caspase activation and is not driven by PAR accumulation, which we call NAD(+)-Keresis. Non-overlapping specificities of FK866 for PDA tumors that rely heavily on NAMPT-catalyzed NAD(+) synthesis and β-lap for cancer cells with elevated NQO1 levels affords high tumor-selectivity. The concept of reducing NAD(+) pools in cancer cells to sensitize them to ROS-mediated cell death by β-lap is a novel strategy with potential application for pancreatic and other types of NQO1+ solid tumors.

  3. Dimethyl fumarate restores apoptosis sensitivity and inhibits tumor growth and metastasis in CTCL by targeting NF-κB

    PubMed Central

    Müller-Decker, Karin; Schroeder, Anne; Brechmann, Markus; Möbs, Markus; Géraud, Cyrill; Assaf, Chalid; Goerdt, Sergij; Krammer, Peter H.; Gülow, Karsten

    2016-01-01

    Despite intensive efforts in recent years, a curative therapy for cutaneous T-cell lymphoma (CTCL) has not yet been developed. Therefore, the establishment of new therapeutic approaches with higher efficacy rates and milder side effects is strongly desired. A characteristic feature of the malignant T-cell population in CTCL is resistance toward cell death resulting from constitutive NF-κB activation. Therefore, NF-κB–dependent cell death resistance represents an interesting therapeutic target in CTCL because an NF-κB–directed therapy would leave bystander T cells widely unaffected. We investigated the effects of dimethyl fumarate (DMF) on CTCL cells in vitro and in vivo. DMF induced cell death in primary patient-derived CD4+ cells and CTCL cell lines, but hardly in T cells from healthy donors. DMF-induced cell death was linked specifically to NF-κB inhibition. To study the impact of DMF in vivo, we developed 2 CTCL xenograft mouse models with different cutaneous localizations of the T-cell infiltrate. DMF treatment delayed the growth of CTCL tumors and prevented formation of distant metastases. In addition, DMF induced increased cell death in primary CTCL tumors and in liver metastases. In summary, DMF treatment represents a remarkable therapeutic option in CTCL because it restores CTCL apoptosis in vitro and in preclinical models in vivo and prevents spreading of the disease to distant sites. DMF treatment is of particular promise in CTCL because DMF is already in successful clinical use in the treatment of psoriasis and multiple sclerosis allowing fast translation into clinical studies in CTCL. PMID:27268084

  4. The loss of Ezh2 drives the pathogenesis of myelofibrosis and sensitizes tumor-initiating cells to bromodomain inhibition

    PubMed Central

    Kanai, Akinori; Mochizuki-Kashio, Makiko; Harada, Hironori; Shimoda, Kazuya

    2016-01-01

    EZH2 is a component of polycomb repressive complex 2 (PRC2) and functions as an H3K27 methyltransferase. Loss-of-function mutations in EZH2 are associated with poorer outcomes in patients with myeloproliferative neoplasms (MPNs), particularly those with primary myelofibrosis (MF [PMF]). To determine how EZH2 insufficiency is involved in the pathogenesis of PMF, we generated mice compound for an Ezh2 conditional deletion and activating mutation in JAK2 (JAK2V617F) present in patients with PMF. The deletion of Ezh2 in JAK2V617F mice markedly promoted the development of MF, indicating a tumor suppressor function for EZH2 in PMF. The loss of Ezh2 in JAK2V617F hematopoietic cells caused significant reductions in H3K27 trimethylation (H3K27me3) levels, resulting in an epigenetic switch to H3K27 acetylation (H3K27ac). These epigenetic switches were closely associated with the activation of PRC2 target genes including Hmga2, an oncogene implicated in the pathogenesis of PMF. The treatment of JAK2V617F/Ezh2-null mice with a bromodomain inhibitor significantly attenuated H3K27ac levels at the promoter regions of PRC2 targets and down-regulated their expression, leading to the abrogation of MF-initiating cells. Therefore, an EZH2 insufficiency not only cooperated with active JAK2 to induce MF, but also conferred an oncogenic addiction to the H3K27ac modification in MF-initiating cells that was capable of being restored by bromodomain inhibition. PMID:27401345

  5. Proteasomal inhibition sensitizes cervical cancer cells to mitomycin C-induced bystander effect: the role of tumor microenvironment.

    PubMed

    Singh, S V; Ajay, A K; Mohammad, N; Malvi, P; Chaube, B; Meena, A S; Bhat, M K

    2015-10-22

    Inaccessibility of drugs to poorly vascularized strata of tumor is one of the limiting factors in cancer therapy. With the advent of bystander effect (BE), it is possible to perpetuate the cellular damage from drug-exposed cells to the unexposed ones. However, the role of infiltrating tumor-associated macrophages (TAMs), an integral part of the tumor microenvironment, in further intensifying BE remains obscure. In the present study, we evaluated the effect of mitomycin C (MMC), a chemotherapeutic drug, to induce BE in cervical carcinoma. By using cervical cancer cells and differentiated macrophages, we demonstrate that MMC induces the expression of FasL via upregulation of PPARγ in both cell types (effector cells) in vitro, but it failed to induce bystander killing in cervical cancer cells. This effect was primarily owing to the proteasomal degradation of death receptors in the cervical cancer cells. Pre-treatment of cervical cancer cells with MG132, a proteasomal inhibitor, facilitates MMC-mediated bystander killing in co-culture and condition medium transfer experiments. In NOD/SCID mice bearing xenografted HeLa tumors administered with the combination of MMC and MG132, tumor progression was significantly reduced in comparison with those treated with either agent alone. FasL expression was increased in TAMs, and the enhanced level of Fas was observed in these tumor sections, thereby causing increased apoptosis. These findings suggest that restoration of death receptor-mediated apoptotic pathway in tumor cells with concomitant activation of TAMs could effectively restrict tumor growth.

  6. NT-16NANOPARTICLE-MEDIATED DELIVERY OF ANTI-Ape1 siRNA SENSITIZES PEDIATRIC BRAIN TUMOR CELLS TO RADIATION THERAPY BY INHIBITING DNA REPAIR

    PubMed Central

    Kievit, Forrest; Stephen, Zachary; Wang, Kui; Dayringer, Christopher; Ellenbogen, Richard; Silber, John; Zhang, Miqin

    2014-01-01

    Pediatric brain tumors are the leading cause of death in children, and survival is frequently accompanied by one or more radiation-induced adverse developmental and psychosocial sequelae. Radiotherapy (RT) is an integral component of the treatment for medulloblastoma (MB) and the only effective adjuvant therapy for ependymoma (EP). Therefore, there is an urgent need to develop strategies to enhance the tumoricidal action of RT while sparing adjacent normal tissue. The multifunctional DNA repair protein Ape1/Ref-1 has been implicated in conferring radiation resistance in pediatric brain tumors. However, inhibiting Ape1 activity in the clinic has been hindered by the lack of safe and effective drugs and siRNA delivery vehicles. We have previously developed a nanoparticle that can deliver siRNA specifically to brain tumors for efficient knockdown of GFP. Here, we aimed to deliver siRNA against Ape1 to improve tumor cell kill after RT. Nanoparticles were loaded with siApe1, or siGFP as a control, and used to treat UW228 (MB) and Res196 (EP) cells. Ape1 expression levels were measured using PCR and Western blot, and the abasic endonuclease activity of Ape1 was determined using an Ape activity assay. Cells were then treated with 137Cs-γ-rays and cell survival monitored using clonogenic assays. DNA repair in cells was assessed though quantification of abasic sites, and resulting double-strand breaks were imaged by γH2AX foci immunostaining. We found that nanoparticle-mediated siApe1 delivery reduced Ape1 expression and activity by greater than 80%. This diminished the shoulder of resistance in survival curves decreasing survival to ∼50% at 1 Gy, and was accompanied by inhibition of DNA repair. Sensitization was specific to abasic site generating treatments as response to paclitaxel was not affected. Therefore, siApe1 loaded nanoparticles may help enhance the therapeutic effect of RT in pediatric brain tumor patients by inhibiting DNA repair.

  7. Sclareol inhibits cell proliferation and sensitizes cells to the antiproliferative effect of bortezomib via upregulating the tumor suppressor caveolin-1 in cervical cancer cells

    PubMed Central

    Zhang, Ting; Wang, Ting; Cai, Peiling

    2017-01-01

    The anticancer effect of sclareol has long been reported, however, the exact mechanisms underlying the antitumorigenic effect of sclareol in cervical carcinoma remain to be fully elucidated. The present study analyzed cell proliferation and cell apoptosis by MTT and FITC-Annexin V assays. The protein levels of caveolin-1 (Cav-1) and copper-zinc superoxide dismutase (SOD)1 were determined by western blotting, and the interaction of Cav1 and HSC70 was investigated by co-immunoprecipitation experiments. The present study found that sclareol inhibited cell proliferation and induced apoptosis in HeLa cells. Two cancer-associated proteins, Cav1 and SOD1 were identified as potential targets of sclareol in HeLa cells. The expression of Cav1 increased when the cells were treated with sclareol, and the protein level of SOD1 was negatively correlated with Cav1. The overexpression of Cav1 enhanced the sensitivity of the HeLa cells to sclareol treatment and downregulated the protein level of SOD1, which exhibited potential associations between Cav1 and SOD1. In addition, sclareol significantly sensitized several cancer cells to the anticancer effect of bortezomib by targeting Cav1 and SOD1. Taken together, the results of the present study demonstrated that sclareol inhibited tumor cell growth through the upregulation of Cav1, and provides a potential therapeutic target for human cancer. PMID:28440485

  8. Sclareol inhibits cell proliferation and sensitizes cells to the antiproliferative effect of bortezomib via upregulating the tumor suppressor caveolin-1 in cervical cancer cells.

    PubMed

    Zhang, Ting; Wang, Ting; Cai, Peiling

    2017-06-01

    The anticancer effect of sclareol has long been reported, however, the exact mechanisms underlying the antitumorigenic effect of sclareol in cervical carcinoma remain to be fully elucidated. The present study analyzed cell proliferation and cell apoptosis by MTT and FITC‑Annexin V assays. The protein levels of caveolin‑1 (Cav‑1) and copper-zinc superoxide dismutase (SOD)1 were determined by western blotting, and the interaction of Cav1 and HSC70 was investigated by co‑immunoprecipitation experiments. The present study found that sclareol inhibited cell proliferation and induced apoptosis in HeLa cells. Two cancer‑associated proteins, Cav1 and SOD1 were identified as potential targets of sclareol in HeLa cells. The expression of Cav1 increased when the cells were treated with sclareol, and the protein level of SOD1 was negatively correlated with Cav1. The overexpression of Cav1 enhanced the sensitivity of the HeLa cells to sclareol treatment and downregulated the protein level of SOD1, which exhibited potential associations between Cav1 and SOD1. In addition, sclareol significantly sensitized several cancer cells to the anticancer effect of bortezomib by targeting Cav1 and SOD1. Taken together, the results of the present study demonstrated that sclareol inhibited tumor cell growth through the upregulation of Cav1, and provides a potential therapeutic target for human cancer.

  9. [18F]-FLT Positron Emission Tomography can be used to image the response of sensitive tumors to PI3-Kinase inhibition with the novel agent GDC-0941

    PubMed Central

    Cawthorne, Christopher; Burrows, Natalie; Gieling, Roben G.; Morrow, Christopher J; Forster, Duncan; Gregory, Jamil; Radigois, Marc; Smigova, Alison; Babur, Muhammad; Simpson, Kathryn; Hodgkinson, Cassandra; Brown, Gavin; McMahon, Adam; Dive, Caroline; Hiscock, Duncan; Wilson, Ian; Williams, Kaye J

    2013-01-01

    The Phosphatidylinositide 3-kinase (PI3-K) pathway is deregulated in a range of cancers, and several targeted inhibitors are entering the clinic. This study aimed to investigate whether the PET tracer 3′-Deoxy-3′-[18F]fluorothymidine ([18F]-FLT) is suitable to mark the effect of the novel PI-3K inhibitor GDC-0941 which has entered phase II clinical trial. CBA nude mice bearing U87 glioma and HCT116 colorectal xenografts were imaged at baseline with [18F]-FLT and at acute (18h) and chronic (186h) timepoints after twice-daily administration of GDC-0941 (50mg/kg) or vehicle. Tumor uptake normalized to blood pool was calculated, and tissue was analyzed at sacrifice for PI3-K pathway inhibition and thymidine kinase (TK1) expression. Uptake of [18F]-FLT was also assessed in tumors inducibly overexpressing a dominant-negative form of the PI3-K p85 subunit Δp85α, as well as HCT116 liver metastases after GDC-0941 therapy. GDC-0941 treatment induced tumor stasis in U87 xenografts, whereas inhibition of HCT116 tumors was more variable. Tumor uptake of [18F]-FLT was significantly reduced following GDC-0941 dosing in responsive tumors at the acute timepoint, and correlated with pharmacodynamic markers of PI3-K signaling inhibition and significant reduction in TK1 expression in U87, but not HCT116, tumors. Reduction of PI3-K signaling via expression of Δp85α significantly reduced tumor growth and [18F]-FLT uptake, as did treatment of HCT116 liver metastases with GDC-0941. These results indicate that [18F]-FLT is a strong candidate for the non-invasive measurement of GDC-0941 action. PMID:23427298

  10. Autophagy Inhibition Improves Chemosensitivity in BRAFV600E Brain Tumors

    PubMed Central

    Levy, Jean M. Mulcahy; Thompson, Joshua C.; Griesinger, Andrea M.; Amani, Vladimir; Donson, Andrew M.; Birks, Diane K.; Morgan, Michael J.; Mirsky, David M.; Handler, Michael H.; Foreman, Nicholas K.; Thorburn, Andrew

    2014-01-01

    Autophagy inhibition is a potential therapeutic strategy in cancer, but it is unknown which tumors will benefit. The BRAFV600E mutation has been identified as important in pediatric CNS tumors and is known to affect autophagy in other tumor types. We evaluated CNS tumor cells with BRAFV600E and found that mutant cells (but not wild type) display high rates of induced autophagy, are sensitive to pharmacologic and genetic autophagy inhibition, and display synergy when the clinically used autophagy inhibitor chloroquine was combined with the Raf inhibitor vemurafenib or standard chemotherapeutics. Importantly we also demonstrate chloroquine can improve vemurafenib sensitivity in a resistant ex vivo primary culture and provide the first demonstration in a patient harboring the V600E mutation treated with vemurafenib that addition of chloroquine can improve clinical outcomes. These findings suggest CNS tumors with BRAFV600E are autophagy-dependent and should be targeted with autophagy inhibition in combination with other therapeutic strategies. PMID:24823863

  11. Breast Tumors with Elevated Expression of 1q Candidate Genes Confer Poor Clinical Outcome and Sensitivity to Ras/PI3K Inhibition

    PubMed Central

    Viveka Thangaraj, Soundara; Periasamy, Jayaprakash; Bhaskar Rao, Divya; Barnabas, Georgina D.; Raghavan, Swetha; Ganesan, Kumaresan

    2013-01-01

    Genomic aberrations are common in cancers and the long arm of chromosome 1 is known for its frequent amplifications in breast cancer. However, the key candidate genes of 1q, and their contribution in breast cancer pathogenesis remain unexplored. We have analyzed the gene expression profiles of 1635 breast tumor samples using meta-analysis based approach and identified clinically significant candidates from chromosome 1q. Seven candidate genes including exonuclease 1 (EXO1) are consistently over expressed in breast tumors, specifically in high grade and aggressive breast tumors with poor clinical outcome. We derived a EXO1 co-expression module from the mRNA profiles of breast tumors which comprises 1q candidate genes and their co-expressed genes. By integrative functional genomics investigation, we identified the involvement of EGFR, RAS, PI3K / AKT, MYC, E2F signaling in the regulation of these selected 1q genes in breast tumors and breast cancer cell lines. Expression of EXO1 module was found as indicative of elevated cell proliferation, genomic instability, activated RAS/AKT/MYC/E2F1 signaling pathways and loss of p53 activity in breast tumors. mRNA–drug connectivity analysis indicates inhibition of RAS/PI3K as a possible targeted therapeutic approach for the patients with activated EXO1 module in breast tumors. Thus, we identified seven 1q candidate genes strongly associated with the poor survival of breast cancer patients and identified the possibility of targeting them with EGFR/RAS/PI3K inhibitors. PMID:24147022

  12. Ehrlich tumor inhibition using doxorubicin containing liposomes.

    PubMed

    Elbialy, Nihal Saad; Mady, Mohsen Mahmoud

    2015-04-01

    Ehrlich tumors were grown in female balb mice by subcutaneous injection of Ehrlich ascites carcinoma cells. Mice bearing Ehrlich tumor were injected with saline, DOX in solution or DOX encapsulated within liposomes prepared from DMPC/CHOL/DPPG/PEG-PE (100:100:60:4) in molar ratio. Cytotoxicity assay showed that the IC50 of liposomes containing DOX was greater than that DOX only. Tumor growth inhibition curves in terms of mean tumor size (cm(3)) were presented. All the DOX formulations were effective in preventing tumor growth compared to saline. Treatment with DOX loaded liposomes displayed a pronounced inhibition in tumor growth than treatment with DOX only. Histopathological examination of the entire tumor sections for the various groups revealed marked differences in cellular features accompanied by varying degrees in necrosis percentage ranging from 12% for saline treated mice to 70% for DOX loaded liposome treated mice. The proposed liposomal formulation can efficiently deliver the drug into the tumor cells by endocytosis (or passive diffusion) and lead to a high concentration of DOX in the tumor cells. The study showed that the formulation of liposomal doxorubicin improved the therapeutic index of DOX and had increased anti-tumor activity against Ehrlich tumor models.

  13. Immunogenic chemotherapy sensitizes tumors to checkpoint blockade therapy

    PubMed Central

    Pfirschke, Christina; Engblom, Camilla; Rickelt, Steffen; Cortez-Retamozo, Virna; Garris, Christopher; Pucci, Ferdinando; Yamazaki, Takahiro; Colame, Vichnou Poirier; Newton, Andita; Redouane, Younes; Lin, Yi-Jang; Wojtkiewicz, Gregory; Iwamoto, Yoshiko; Mino-Kenudson, Mari; Huynh, Tiffany G.; Hynes, Richard O.; Freeman, Gordon J.; Kroemer, Guido; Zitvogel, Laurence; Weissleder, Ralph; Pittet, Mikael J.

    2016-01-01

    SUMMARY Checkpoint blockade immunotherapies can be extraordinarily effective, but may benefit only the minority of patients whose tumors are pre-infiltrated by T cells. Here, using lung adenocarcinoma mouse models, including genetic models, we show that autochthonous tumors that lacked T cell infiltration and resisted current treatment options could be successfully sensitized to host antitumor T cell immunity when using appropriately selected immunogenic drugs (e.g. oxaliplatin combined with cyclophosphamide for treatment against tumors expressing oncogenic Kras and lacking Trp53). The antitumor response was triggered by direct drug actions on tumor cells, relied on innate immune sensing through toll-like receptor 4 signaling, and ultimately depended on CD8+ T cell antitumor immunity. Furthermore, instigating tumor infiltration by T cells sensitized tumors to checkpoint inhibition and controlled cancer durably. These findings indicate that the proportion of cancers responding to checkpoint therapy can be feasibly and substantially expanded by combining checkpoint blockade with immunogenic drugs. PMID:26872698

  14. Therapeutic Anti-Tumor Vaccines: From Tumor Inhibition to Enhancement

    PubMed Central

    Chiarella, Paula; Reffo, Verónica; Bruzzo, Juan; Bustuoabad, Oscar D.; Ruggiero, Raúl A.

    2008-01-01

    Numerous immunization trials have proved successful in preventing the growth of experimental animal tumors and human hepatocarcinomas induced by hepatitis B virus. These results have prompted researchers and physicians to use vaccines in a therapeutic mode but the results have, in general, been disappointing even when strongly immunogenic murine tumors were concerned. Data presented herein suggest that immunotherapy induced by a single dose of a dendritic cell-based vaccine against a murine established tumor or against residual tumor cells after debulking the primary tumor, can render not only inhibitory or null but also stimulatory effects on tumor growth. These different effects might be dependent on where the system is located in the immune response curve that relates the quantity of the immune response to the quantity of target tumor cells. We suggest that high ratios render tumor inhibition, medium and very low ratios render null effects and low ratios—between medium and very low ones—render tumor stimulation. Since the magnitude of these ratios would depend on the antigenic profile of the tumor, the immunogenic strength of the vaccine used and the immunological state of the host, studies aimed to determine the magnitude of these variables in each particular case, seem to be necessary as a pre-condition to design rational immunotherapeutic approaches to cancer. In contrast, if these studies are neglected, the worst thing that an immunotherapist could face is not merely a null effect but enhancement of tumor growth. PMID:21892285

  15. Targeting tumor cells by enhancing radiation sensitivity.

    PubMed

    McKenna, W Gillies; Muschel, Ruth J

    2003-12-01

    The work of Al Knudson created the paradigm in which we see cancer as a result of the accumulation of multiple mutations. Our goal has been to exploit these mutations to develop strategies to enhance therapy for cancer by targeting the malignant cell while sparing the normal tissue. In studying the RAS oncogene, we observed that its expression when activated resulted in enhanced radioresistance. Conversely, inhibition of RAS made cells with activated RAS more radiosensitive. Hence, we postulated that it would be possible to sensitize tumors with RAS mutations to radiation without affecting the sensitivity of the normal tissue in patients with such tumors. This proved to be the case in animal models and has led to current clinical trials. These studies raised the question of identifying the downstream effectors of RAS that are responsible for altering the radiosensitivity of cells. We have found that phosphoinositide-3-kinase (PI3 kinase) is a critical component of this pathway. Blocking PI3 kinase enhanced the radiation response in vitro or in vivo of cells actively signaling through that pathway, but did not affect cells not actively signaling through PI3 kinase at the time of irradiation. Identification of tumors with active signaling in this pathway by immunohistochemical staining for phosphorylated AKT, the downstream target of PI3 kinase correlated with those patients for which radiation failed to achieve local control. Thus, characterization of the active signaling pathways in a given tumor might enable the selection of patients likely to respond to radiation. Pathways upstream from RAS may also be useful targets to consider for enhancing radiation therapy. Epidermal growth factor receptor (EGFR), which is upstream of PI3 kinase, may also mediate resistance through a common pathway. In addition to EGFR and RAS, PTEN can also regulate the PI3 kinase pathway. Identifying a common signal for EGFR, RAS, and PTEN that results in radiation resistance may uncover

  16. Tumor Necrosis Factor Alpha Inhibits L-Type Ca2+ Channels in Sensitized Guinea Pig Airway Smooth Muscle through ERK 1/2 Pathway

    PubMed Central

    Reyes-García, Jorge; Flores-Soto, Edgar; Solís-Chagoyán, Héctor; Sommer, Bettina; Díaz-Hernández, Verónica; García-Hernández, Luz María

    2016-01-01

    Tumor necrosis factor alpha (TNF-α) is a potent proinflammatory cytokine that plays a significant role in the pathogenesis of asthma by inducing hyperresponsiveness and airway remodeling. TNF-α diminishes the L-type voltage dependent Ca2+ channel (L-VDCC) current in cardiac myocytes, an observation that seems paradoxical. In guinea pig sensitized tracheas KCl responses were lower than in control tissues. Serum from sensitized animals (Ser-S) induced the same phenomenon. In tracheal myocytes from nonsensitized (NS) and sensitized (S) guinea pigs, an L-VDCC current (ICa) was observed and diminished by Ser-S. The same decrease was detected in NS myocytes incubated with TNF-α, pointing out that this cytokine might be present in Ser-S. We observed that a small-molecule inhibitor of TNF-α (SMI-TNF) and a TNF-α receptor 1 (TNFR1) antagonist (WP9QY) reversed ICa decrease induced by Ser-S in NS myocytes, confirming the former hypothesis. U0126 (a blocker of ERK 1/2 kinase) also reverted the decrease in ICa. Neither cycloheximide (a protein synthesis inhibitor) nor actinomycin D (a transcription inhibitor) showed any effect on the TNF-α-induced ICa reduction. We found that CaV1.2 and CaV1.3 mRNA and proteins were expressed in tracheal myocytes and that sensitization did not modify them. In cardiac myocytes, ERK 1/2 phosphorylates two sites of the L-VDCC, augmenting or decreasing ICa; we postulate that, in guinea pig tracheal smooth muscle, TNF-α diminishes ICa probably by phosphorylating the L-VDCC site that reduces its activity through the ERK1/2 MAP kinase pathway. PMID:27445440

  17. Tumor Necrosis Factor Alpha Inhibits L-Type Ca(2+) Channels in Sensitized Guinea Pig Airway Smooth Muscle through ERK 1/2 Pathway.

    PubMed

    Reyes-García, Jorge; Flores-Soto, Edgar; Solís-Chagoyán, Héctor; Sommer, Bettina; Díaz-Hernández, Verónica; García-Hernández, Luz María; Montaño, Luis M

    2016-01-01

    Tumor necrosis factor alpha (TNF-α) is a potent proinflammatory cytokine that plays a significant role in the pathogenesis of asthma by inducing hyperresponsiveness and airway remodeling. TNF-α diminishes the L-type voltage dependent Ca(2+) channel (L-VDCC) current in cardiac myocytes, an observation that seems paradoxical. In guinea pig sensitized tracheas KCl responses were lower than in control tissues. Serum from sensitized animals (Ser-S) induced the same phenomenon. In tracheal myocytes from nonsensitized (NS) and sensitized (S) guinea pigs, an L-VDCC current (ICa) was observed and diminished by Ser-S. The same decrease was detected in NS myocytes incubated with TNF-α, pointing out that this cytokine might be present in Ser-S. We observed that a small-molecule inhibitor of TNF-α (SMI-TNF) and a TNF-α receptor 1 (TNFR1) antagonist (WP9QY) reversed ICa decrease induced by Ser-S in NS myocytes, confirming the former hypothesis. U0126 (a blocker of ERK 1/2 kinase) also reverted the decrease in ICa. Neither cycloheximide (a protein synthesis inhibitor) nor actinomycin D (a transcription inhibitor) showed any effect on the TNF-α-induced ICa reduction. We found that CaV1.2 and CaV1.3 mRNA and proteins were expressed in tracheal myocytes and that sensitization did not modify them. In cardiac myocytes, ERK 1/2 phosphorylates two sites of the L-VDCC, augmenting or decreasing ICa; we postulate that, in guinea pig tracheal smooth muscle, TNF-α diminishes ICa probably by phosphorylating the L-VDCC site that reduces its activity through the ERK1/2 MAP kinase pathway.

  18. Inhibition of heat-shock protein 90 sensitizes liver cancer stem-like cells to magnetic hyperthermia and enhances anti-tumor effect on hepatocellular carcinoma-burdened nude mice

    PubMed Central

    Yang, Rui; Tang, Qiusha; Miao, Fengqin; An, Yanli; Li, Mengfei; Han, Yong; Wang, Xihui; Wang, Juan; Liu, Peidang; Chen, Rong

    2015-01-01

    Purpose To explore the thermoresistance and expression of heat-shock protein 90 (HSP90) in magnetic hyperthermia-treated human liver cancer stem-like cells (LCSCs) and the effects of a heat-shock protein HSP90 inhibitor 17-allylamino-17-demethoxgeldanamycin (17-AAG) on hepatocellular carcinoma-burdened nude mice. Methods CD90+ LCSCs were isolated by magnetic-activated cell sorting from BEL-7404. Spheroid formation, proliferation, differentiation, drug resistance, and tumor formation assays were performed to identify stem cell characteristics. CD90-targeted thermosensitive magnetoliposomes (TMs)-encapsulated 17-AAG (CD90@17-AAG/TMs) was prepared by reverse-phase evaporation and its characteristics were studied. Heat tolerance in CD90+ LCSCs and the effect of CD90@17-AAG/TMs-mediated heat sensitivity were examined in vitro and in vivo. Results CD90+ LCSCs showed significant stem cell-like properties. The 17-AAG/TMs were successfully prepared and were spherical in shape with an average size of 128.9±7.7 nm. When exposed to magnetic hyperthermia, HSP90 was up-regulated in CD90+ LCSCs. CD90@17-AAG/TMs inhibited the activity of HSP90 and increased the sensitivity of CD90+ LCSCs to magnetic hyperthermia. Conclusion The inhibition of HSP90 could sensitize CD90+ LCSCs to magnetic hyperthermia and enhance its anti-tumor effects in vitro and in vivo. PMID:26677324

  19. Cellular hierarchy as a determinant of tumor sensitivity to chemotherapy.

    PubMed

    Rodriguez-Brenes, Ignacio; Kurtova, Antonina V; Lin, Christopher; Lee, Yu-Cheng; Xiao, Jing; Mims, Martha P; Chan, Keith Syson; Wodarz, Dominik

    2017-02-24

    Chemotherapy has been shown to enrich cancer stem cells in tumors. Recently, we demonstrated that administration of chemotherapy to human bladder cancer xenografts could trigger a wound-healing response that mobilizes quiescent tumor stem cells into active proliferation, leading to a loss of sensitivity to chemotherapy. Different bladder cancer xenografts, however, demonstrate differential sensitivities to chemotherapy, the basis of which is not understood. Using mathematical models, we show here that characteristics of the tumor cell hierarchy can be crucial for determining the sensitivity of tumors to drug therapy, under the assumption that stem cell enrichment is the primary basis for drug resistance. Our model predicted a weaker response to therapy if negative feedback from differentiated tumor cells inhibited the rate of tumor stem cell division. If this negative feedback was less pronounced, treatment response was predicted to be enhanced. Negative feedback on the rate of tumor cell division promoted a permanent rise of the tumor stem cell population over time both in the absence of treatment and even more so during drug therapy. Model application to data from chemotherapy-treated, patient-derived xenografts indicated support for model predictions. These findings call for further research into feedback mechanisms that might remain active in cancers, and they highlight the presence of feedback as an indication to potentially combine chemotherapy with approaches that limit the process of tumor stem cell enrichment.

  20. The TPM3-NTRK1 rearrangement is a recurring event in colorectal carcinoma and is associated with tumor sensitivity to TRKA kinase inhibition.

    PubMed

    Ardini, Elena; Bosotti, Roberta; Borgia, Andrea Lombardi; De Ponti, Cristina; Somaschini, Alessio; Cammarota, Rosaria; Amboldi, Nadia; Raddrizzani, Laura; Milani, Andrea; Magnaghi, Paola; Ballinari, Dario; Casero, Daniele; Gasparri, Fabio; Banfi, Patrizia; Avanzi, Nilla; Saccardo, Maria B; Alzani, Rachele; Bandiera, Tiziano; Felder, Eduard; Donati, Daniele; Pesenti, Enrico; Sartore-Bianchi, Andrea; Gambacorta, Marcello; Pierotti, Marco A; Siena, Salvatore; Veronese, Silvio; Galvani, Arturo; Isacchi, Antonella

    2014-12-01

    The NTRK1 gene encodes Tropomyosin-related kinase A (TRKA), the high-affinity Nerve Growth Factor Receptor. NTRK1 was originally isolated from a colorectal carcinoma (CRC) sample as component of a somatic rearrangement (TPM3-NTRK1) resulting in expression of the oncogenic chimeric protein TPM3-TRKA, but there has been no subsequent report regarding the relevance of this oncogene in CRC. The KM12 human CRC cell line expresses the chimeric TPM3-TRKA protein and is hypersensitive to TRKA kinase inhibition. We report the detailed characterization of the TPM3-NTRK1 genomic rearrangement in KM12 cells and through a cellular screening approach, the identification of NMS-P626, a novel highly potent and selective TRKA inhibitor. NMS-P626 suppressed TPM3-TRKA phosphorylation and downstream signaling in KM12 cells and showed remarkable antitumor activity in mice bearing KM12 tumors. Finally, using quantitative reverse transcriptase PCR and immunohistochemistry (IHC) we identified the TPM3-NTRK1 rearrangement in a CRC clinical sample, therefore suggesting that this chromosomal translocation is indeed a low frequency recurring event in CRC and that such patients might benefit from therapy with TRKA kinase inhibitors.

  1. High-throughput mutation profiling of CTCL samples reveals KRAS and NRAS mutations sensitizing tumors toward inhibition of the RAS/RAF/MEK signaling cascade

    PubMed Central

    Kießling, Michael K.; Oberholzer, Patrick A.; Mondal, Chandrani; Karpova, Maria B.; Zipser, Marie C.; Lin, William M.; Girardi, Michael; MacConaill, Laura E.; Kehoe, Sarah M.; Hatton, Charlie; French, Lars E.; Garraway, Levi A.; Polier, Gernot; Süss, Dorothee; Klemke, Claus-Detlev; Krammer, Peter H.

    2011-01-01

    Cutaneous T-cell lymphomas (CTCLs) are malignancies of skin-homing lymphoid cells, which have so far not been investigated thoroughly for common oncogenic mutations. We screened 90 biopsy specimens from CTCL patients (41 mycosis fungoides, 36 Sézary syndrome, and 13 non–mycosis fungoides/Sézary syndrome CTCL) for somatic mutations using OncoMap technology. We detected oncogenic mutations for the RAS pathway in 4 of 90 samples. One mycosis fungoides and one pleomorphic CTCL harbored a KRASG13D mutation; one Sézary syndrome and one CD30+ CTCL harbored a NRASQ61K amino acid change. All mutations were found in stage IV patients (4 of 42) who showed significantly decreased overall survival compared with stage IV patients without mutations (P = .04). In addition, we detected a NRASQ61K mutation in the CTCL cell line Hut78. Knockdown of NRAS by siRNA induced apoptosis in mutant Hut78 cells but not in CTCL cell lines lacking RAS mutations. The NRASQ61K mutation sensitized Hut78 cells toward growth inhibition by the MEK inhibitors U0126, AZD6244, and PD0325901. Furthermore, we found that MEK inhibitors exclusively induce apoptosis in Hut78 cells. Taken together, we conclude that RAS mutations are rare events at a late stage of CTCL, and our preclinical results suggest that such late-stage patients profit from MEK inhibitors. PMID:21209378

  2. Enhancement or inhibition of tumor growth by interferon: dependence on treatment protocol.

    PubMed

    Murasko, D M; Fresa, K; Mark, R

    1983-12-15

    MSC cells are tumor cells originally induced in BALB/c mice by Moloney sarcoma virus. In these studies we demonstrated that, although these tumor cells are sensitive in vitro both to lysis by NK or NK-like cells and to the growth-inhibitory effect of murine L-cell interferon (IFN), the growth of the tumor in vivo could be either inhibited or enhanced by IFN. The outcome of in vivo IFN treatment was dependent on the timing and route of IFN administration relative to tumor challenge. IFN given systematically at the same time as tumor challenge resulted in enhancement of primary tumor formation, rate of tumor growth and subsequent progressive tumor growth. In contrast, IFN administered at the site of tumor inoculation on days 1-3 after tumor challenge inhibited tumor formation and growth. Histopathology of tissue sections obtained from the site of tumor challenge confirmed these results. Similar studies performed in mice given 450 rads of X-irradiation showed that IFN could still inhibit tumor growth when administered at the site of tumor inoculation on days 1-3 after tumor challenge. IFN administered simultaneously with tumor challenge, however, did not enhance tumor growth in irradiated mice. These results are consistent with the interpretation that 1) inhibition of MSC-induced tumor growth by IFN has a radioresistant component and 2) the enhancement of MSC-induced tumor formation by IFN is dependent on interaction with a radiosensitive population of cells, possibly lymphoid cells.

  3. Brain Cancer Stem Cells Display Preferential Sensitivity to Akt Inhibition

    PubMed Central

    Eyler, Christine E.; Foo, Wen-Chi; LaFiura, Katherine M.; McLendon, Roger E.; Hjelmeland, Anita B.; Rich, Jeremy N.

    2009-01-01

    Malignant brain tumors are among the most lethal cancers, and conventional therapies are largely limited to palliation. Novel therapies targeted against specific molecular pathways may offer improved efficacy and reduced toxicity compared to conventional therapies, but initial clinical trials of molecular targeted agents in brain cancer therapy have been frequently disappointing. In brain tumors and other cancers, subpopulations of tumor cells have recently been characterized by their ability to self-renew and initiate tumors. Although these cancer stem cells, or tumor initiating cells, are often only present in small numbers in human tumors, mounting evidence suggests that cancer stem cells contribute to tumor maintenance and therapeutic resistance. Thus, the development of therapies that target cancer stem cell signal transduction and biologies may improve brain tumor patient survival. We now demonstrate that populations enriched for cancer stem cells are preferentially sensitive to an inhibitor of Akt, a prominent cell survival and invasion signaling node. Treatment with an Akt inhibitor more potently reduced the numbers of viable brain cancer stem cells relative to matched non-stem cancer cells associated with a preferential induction of apoptosis and a suppression of neurosphere formation. Akt inhibition also reduced the motility and invasiveness of all tumor cells but had a greater impact on cancer stem cell behaviors. Furthermore, inhibition of Akt activity in cancer stem cells increased survival of immunocompromised mice bearing human glioma xenografts in vivo. Together, these results suggest that Akt inhibitors may function as effective anti-cancer stem cell therapies. PMID:18802038

  4. Obesity inhibits lymphangiogenesis in prostate tumors.

    PubMed

    Moreira, Ângela; Pereira, Sofia S; Machado, Christiane L; Morais, Tiago; Costa, Madalena; Monteiro, Mariana P

    2014-01-01

    Lymphangiogenesis is the process that leads to new lymphatic vessels formation from preexisting blood vessels in the presence of appropriate inducing signals, which in pathologic conditions such as cancer, may contribute to tumor cells dissemination. The aim of the present study was to study the role of obesity, leptin and insulin in tumor lymphangiogenesis. For that, we have quantified the lymphatic vessels in prostate tumors through their immunohistochemistry staining by Lyve-1 in RM1 prostate tumors induced in different obese mice models (ob/ob, db/db and diet induced obese (DIO) and in normal weight C57BL/6J mice (control). Lymph vessels density was determined by Lyve-1 immunohistochemistry of prostate adenocarcinomas, while the percentage of the Lyve-1 stained area and lymphatic vessels number were obtained using a morphometric computerized tool. Obese ob/ob and DIO mice presented prostate tumors that were significantly larger (p<0.001) than controls, while tumors of db/db mice were significantly smaller (p=0.047). Lyve-1 expression was significantly higher in prostate tumors of DIO mice compared to tumors of db/db mice (p<0.05); furthermore Lyve-1 expression was negatively correlated with the percentage of the epididymal fat and body weight (p<0.01). No significantly correlations were found between Lyve-1 expression and tumor weight and leptin or insulin plasma levels. Our results suggest that obesity may have a protective effect against prostate cancer dissemination by inhibiting lymphangiogenesis through a still unidentified mechanism that appears not to involve leptin or insulin.

  5. Role of the nitric oxide synthase pathway in inhibition of growth of interferon-sensitive and interferon-resistant Rickettsia prowazekii strains in L929 cells treated with tumor necrosis factor alpha and gamma interferon.

    PubMed Central

    Turco, J; Winkler, H H

    1993-01-01

    The ability of tumor necrosis factor alpha (TNF-alpha) alone and in combination with gamma interferon (IFN-gamma) to inhibit the growth of interferon-sensitive and -resistant Rickettsia prowazekii strains in mouse L929 cells was examined, and the possible role of the nitric oxide synthase pathway in the suppression of rickettsial growth induced by TNF-alpha, IFN-gamma, or both cytokines was evaluated. TNF-alpha inhibited the growth of strains Madrid E (IFN-gamma sensitive and alpha/beta interferon [IFN-alpha/beta] sensitive) and Breinl (IFN-gamma sensitive and IFN-alpha/beta resistant), but not that of strain 83-2P (IFN-gamma resistant and IFN-alpha/beta resistant), in L929 cells. Inhibition of the growth of the Madrid E strain in L929 cells treated with TNF-alpha and IFN-gamma in combination was greater than that observed with either TNF-alpha or IFN-gamma alone. Similarly, inhibition of the growth of the Breinl strain in L929 cells treated with both cytokines was greater than that observed with TNF-alpha alone; however, it did not differ significantly from the inhibition observed with IFN-gamma alone. Although strain 83-2P was resistant to TNF-alpha or IFN-gamma alone, its growth was inhibited in L929 cells treated with TNF-alpha and IFN-gamma in combination. Nitrite production was measured in mock-infected and infected L929 cell cultures, and the nitric oxide synthase inhibitors NG-methyl-L-arginine (NGMA) and aminoguanidine were used to evaluate the role of the nitric oxide synthase pathway in cytokine-induced inhibition of rickettsial growth. Nitrite production was induced in mock-infected or R. prowazekii-infected L929 cell cultures treated with IFN-gamma plus TNF-alpha, but not in mock-infected cultures that were untreated or treated with IFN-gamma or TNF-alpha alone. Nitrite production was also not induced in untreated, R. prowazekii-infected cultures; however, in some instances, it was induced in infected cultures treated with IFN-gamma or TNF-alpha alone

  6. Atypical E2Fs inhibit tumor angiogenesis.

    PubMed

    Weijts, B G M W; Westendorp, B; Hien, B T; Martínez-López, L M; Zijp, M; Thurlings, I; Thomas, R E; Schulte-Merker, S; Bakker, W J; de Bruin, A

    2017-09-18

    Atypical E2F transcription factors (E2F7 and E2F8) function as key regulators of cell cycle progression and their inactivation leads to spontaneous cancer formation in mice. However, the mechanism of the tumor suppressor functions of E2F7/8 remain obscure. In this study we discovered that atypical E2Fs control tumor angiogenesis, one of the hallmarks of cancer. We genetically inactivated atypical E2Fs in epithelial and mesenchymal neoplasm and analyzed blood vessel formation in three different animal models of cancer. Tumor formation was either induced by application of 7,12-Dimethylbenz(a)anthracene/12-O-Tetradecanoylphorbol-13-acetate or by Myc/Ras overexpression. To our surprise, atypical E2Fs suppressed tumor angiogenesis in all three cancer models, which is in a sharp contrast to previous findings showing that atypical E2Fs promote angiogenesis during fetal development in mice and zebrafish. Real-time imaging in zebrafish displayed that fluorescent-labeled blood vessels showed enhanced intratumoral branching in xenografted E2f7/8-deficient neoplasms compared with E2f7/8-proficient neoplasms. DLL4 expression, a key negative inhibitor of vascular branching, was decreased in E2f7/8-deficient neoplastic cells, indicating that E2F7/8 might inhibit intratumoral vessel branching via induction of DLL4.Oncogene advance online publication, 18 September 2017; doi:10.1038/onc.2017.336.

  7. Amiodarone Inhibits Apamin-Sensitive Potassium Currents

    PubMed Central

    Turker, Isik; Yu, Chih-Chieh; Chang, Po-Cheng; Chen, Zhenhui; Sohma, Yoshiro; Lin, Shien-Fong; Chen, Peng-Sheng; Ai, Tomohiko

    2013-01-01

    Background Apamin sensitive potassium current (IKAS), carried by the type 2 small conductance Ca2+-activated potassium (SK2) channels, plays an important role in post-shock action potential duration (APD) shortening and recurrent spontaneous ventricular fibrillation (VF) in failing ventricles. Objective To test the hypothesis that amiodarone inhibits IKAS in human embryonic kidney 293 (HEK-293) cells. Methods We used the patch-clamp technique to study IKAS in HEK-293 cells transiently expressing human SK2 before and after amiodarone administration. Results Amiodarone inhibited IKAS in a dose-dependent manner (IC50, 2.67±0.25 µM with 1 µM intrapipette Ca2+). Maximal inhibition was observed with 50 µM amiodarone which inhibited 85.6±3.1% of IKAS induced with 1 µM intrapipette Ca2+ (n = 3). IKAS inhibition by amiodarone was not voltage-dependent, but was Ca2+-dependent: 30 µM amiodarone inhibited 81.5±1.9% of IKAS induced with 1 µM Ca2+ (n = 4), and 16.4±4.9% with 250 nM Ca2+ (n = 5). Desethylamiodarone, a major metabolite of amiodarone, also exerts voltage-independent but Ca2+ dependent inhibition of IKAS. Conclusion Both amiodarone and desethylamiodarone inhibit IKAS at therapeutic concentrations. The inhibition is independent of time and voltage, but is dependent on the intracellular Ca2+ concentration. SK2 current inhibition may in part underlie amiodarone's effects in preventing electrical storm in failing ventricles. PMID:23922993

  8. Dioscin inhibits colon tumor growth and tumor angiogenesis through regulating VEGFR2 and AKT/MAPK signaling pathways

    SciTech Connect

    Tong, Qingyi; Qing, Yong; Wu, Yang; Hu, Xiaojuan; Jiang, Lei; Wu, Xiaohua

    2014-12-01

    Dioscin has shown cytotoxicity against cancer cells, but its in vivo effects and the mechanisms have not elucidated yet. The purpose of the current study was to assess the antitumor effects and the molecular mechanisms of dioscin. We showed that dioscin could inhibit tumor growth in vivo and has no toxicity at the test condition. The growth suppression was accompanied by obvious blood vessel decrease within solid tumors. We also found dioscin treatment inhibited the proliferation of cancer and endothelial cell lines, and most sensitive to primary cultured human umbilical vein endothelial cells (HUVECs). What's more, analysis of HUVECs migration, invasion, and tube formation exhibited that dioscin has significantly inhibitive effects to these actions. Further analysis of blood vessel formation in the matrigel plugs indicated that dioscin could inhibit VEGF-induced blood vessel formation in vivo. We also identified that dioscin could suppress the downstream protein kinases of VEGFR2, including Src, FAK, AKT and Erk1/2, accompanied by the increase of phosphorylated P38MAPK. The results potently suggest that dioscin may be a potential anticancer drug, which efficiently inhibits angiogenesis induced by VEGFR2 signaling pathway as well as AKT/MAPK pathways. - Highlights: • Dioscin inhibits tumor growth in vivo and does not exhibit any toxicity. • Dioscin inhibits angiogenesis within solid tumors. • Dioscin inhibits the proliferation, migration, invasion, and tube formation of HUVECs. • Dioscin inhibits VEGF–induced blood vessel formation in vivo. • Dioscin inhibits VEGFR2 signaling pathway as well as AKT/MAPK pathway.

  9. Alk5 inhibition increases delivery of macromolecular and protein-bound contrast agents to tumors

    PubMed Central

    Daldrup-Link, Heike E.; Mohanty, Suchismita; Ansari, Celina; Ito, Ken; Hong, Su Hyun; Hoffmann, Matthias; Pisani, Laura; Boudreau, Nancy; Gambhir, Sanjiv Sam; Coussens, Lisa M.

    2016-01-01

    Limited transendothelial permeability across tumor microvessels represents a significant bottleneck in the development of tumor-specific diagnostic agents and theranostic drugs. Here, we show an approach to increase transendothelial permeability of macromolecular and nanoparticle-based contrast agents via inhibition of the type I TGF-β receptor, activin-like kinase 5 (Alk5), in tumors. Alk5 inhibition significantly increased tumor contrast agent delivery and enhancement on imaging studies, while healthy organs remained relatively unaffected. Imaging data correlated with significantly decreased tumor interstitial fluid pressure, while tumor vascular density remained unchanged. This immediately clinically translatable concept involving Alk5 inhibitor pretreatment prior to an imaging study could be leveraged for improved tumor delivery of macromolecular and nanoparticle-based imaging probes and, thereby, facilitate development of more sensitive imaging tests for cancer diagnosis, enhanced tumor characterization, and personalized, image-guided therapies. PMID:27182558

  10. Sensitization of meningeal nociceptors: inhibition by naproxen

    PubMed Central

    Levy, Dan; Zhang, Xi-Chun; Jakubowski, Moshe; Burstein, Rami

    2009-01-01

    Migraine attacks associated with throbbing (manifestation of peripheral sensitization) and cutaneous allodynia (manifestation of central sensitization) are readily terminated by intravenous administration of a non-selective cyclooxygenase (COX) inhibitor. Evidence that sensitization of rat central trigeminovascular neurons was also terminated in vivo by non-selective COX inhibition has led us to propose that COX inhibitors may act centrally in the dorsal horn. In the present study, we examined whether COX inhibition can also suppress peripheral sensitization in meningeal nociceptors. Using single-unit recording in the trigeminal ganglion in vivo, we found that intravenous infusion of naproxen, a non-selective COX inhibitor, reversed measures of sensitization induced in meningeal nociceptors by prior exposure of the dura to inflammatory soup (IS): ongoing activity of Aδ- and C-units and their response magnitude to mechanical stimulation of the dura, which were enhanced after IS, returned to baseline after naproxen infusion. Topical application of naproxen or the selective COX-2 inhibitor N-[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide (NS-398) onto the dural receptive field of Aδ- and C-unit nociceptors also reversed the neuronal hyper-responsiveness to mechanical stimulation of the dura. The findings suggest that local COX activity in the dura could mediate the peripheral sensitization that underlies migraine headache. PMID:18333963

  11. Gabapentin inhibits central sensitization during migraine.

    PubMed

    Zhang, Yanbo; Shao, Guo; Zhang, Wei; Li, Sijie; Niu, Jingzhong; Hu, Dongmei; Yang, Mingfeng; Ji, Xunming

    2013-11-15

    Peripheral and central sensitizations are phenomena that occur during migraine. The role of pentin, a migraine preventive drug, on central sensitization remains unclear. In this study, a rat model of migraine was established by electrical stimulation of the trigeminal ganglion, and the an-imals were given intragastric gabapentin. Changes in amino acid content in the cerebrospinal fluid and protein kinase C membrane translocation in the spinal trigeminal nucleus were examined to clarify the mechanisms underlying the efficacy of gabapentin in the treatment of central sensitization during migraine. Electrophysiology, liquid chromatography-mass spectrometry and western blot analysis results revealed that gabapentin reduces neuronal excitability in the spinal nucleus in the trigeminal nerve, decreases excitatory amino acid content and inhibits the activation of protein ki-nase C. This provides evidence that excitatory amino acids and protein kinase C are involved in the formation and maintenance of central sensitization during migraine. Gabapentin inhibits migraine by reducing excitatory amino acid content in the cerebrospinal fluid and inhibiting protein kinase C ac-tivation.

  12. FASN Inhibition and Taxane Treatment Combine to Enhance Anti-tumor Efficacy in Diverse Xenograft Tumor Models through Disruption of Tubulin Palmitoylation and Microtubule Organization and FASN Inhibition-Mediated Effects on Oncogenic Signaling and Gene Expression.

    PubMed

    Heuer, Timothy S; Ventura, Richard; Mordec, Kasia; Lai, Julie; Fridlib, Marina; Buckley, Douglas; Kemble, George

    2017-02-01

    Palmitate, the enzymatic product of FASN, and palmitate-derived lipids support cell metabolism, membrane architecture, protein localization, and intracellular signaling. Tubulins are among many proteins that are modified post-translationally by acylation with palmitate. We show that FASN inhibition with TVB-3166 or TVB-3664 significantly reduces tubulin palmitoylation and mRNA expression. Disrupted microtubule organization in tumor cells is an additional consequence of FASN inhibition. FASN inhibition combined with taxane treatment enhances inhibition of in vitro tumor cell growth compared to treatment with either agent alone. In lung, ovarian, prostate, and pancreatic tumor xenograft studies, FASN inhibition and paclitaxel or docetaxel combine to inhibit xenograft tumor growth with significantly enhanced anti-tumor activity. Tumor regression was observed in 3 of 6 tumor xenograft models. FASN inhibition does not affect cellular taxane concentration in vitro. Our data suggest a mechanism of enhanced anti-tumor activity of the FASN and taxane drug combination that includes inhibition of tubulin palmitoylation and disruption of microtubule organization in tumor cells, as well as a sensitization of tumor cells to FASN inhibition-mediated effects that include gene expression changes and inhibition of β-catenin. Together, the results strongly support investigation of combined FASN inhibition and taxane treatment as a therapy for a variety of human cancers. Copyright © 2016 3-V Biosciences. Published by Elsevier B.V. All rights reserved.

  13. Murine macrophage heparanase: inhibition and comparison with metastatic tumor cells

    SciTech Connect

    Savion, N.; Disatnik, M.H.; Nevo, Z.

    1987-01-01

    Circulating macrophages and metastatic tumor cells can penetrate the vascular endothelium and migrate from the circulatory system to extravascular compartments. Both activated murine macrophages and different metastatic tumor cells attach, invade, and penetrate confluent vascular endothelial cell monolayer in vitro, by degrading heparan sulfate proteoglycans in the subendothelial extracellular matrix. The sensitivity of the enzymes from the various sources degrading the heparan sulfate proteoglycan was challenged and compared by a series of inhibitors. Activated macrophages demonstrate a heparanase with an endoglycosidase activity that cleaves from the (/sup 35/S)O/sub 4//sup -/-labeled heparan sulfate proteoglycans of the extracellular matrix 10 kDa glycosaminoglycan fragments. The degradation of (/sup 35/S)O/sub 4//sup -/-labeled extracellular matrix proteoglycans by the macrophages' heparanase is significantly inhibited in the presence of heparan sulfate (10..mu..g/ml), arteparon (10..mu..g/ml), and heparin at a concentration of 3 ..mu..g/ml. Degradation of this heparan sulfate proteoglycan is a two-step sequential process involving protease activity followed by heparanase activity. B16-BL6 metastatic melanoma cell heparanase, which is also a cell-associated enzyme, was inhibited by heparin to the same extent as the macrophage haparanase. On the other hand, heparanase of the highly metastatic variant (ESb) of a methylcholanthrene-induced T lymphoma, which is an extracellular enzyme released by the cells to the incubation medium, was more sensitive to heparin and arteparon than the macrophages' heparanase. These results may indicate the potential use of heparin or other glycosaminoglycans as specific and differential inhibitors for the formation in certain cases of blood-borne tumor metastasis.

  14. The tumor microenvironment underlies acquired resistance to CSF1R inhibition in gliomas

    PubMed Central

    Quail, Daniela F.; Bowman, Robert L.; Akkari, Leila; Quick, Marsha L.; Schuhmacher, Alberto J.; Huse, Jason T.; Holland, Eric C.; Sutton, James C.; Joyce, Johanna A.

    2017-01-01

    Macrophages accumulate with glioblastoma multiforme (GBM) progression, and can be targeted via inhibition of colony stimulating factor-1 receptor (CSF-1R) to regress high-grade tumors in animal models of this cancer. However, whether and how resistance emerges in response to sustained CSF-1R blockade is unknown. We show that while overall survival is significantly prolonged, tumors recur in >50% of mice. Gliomas re-establish sensitivity to CSF-1R inhibition upon transplantation, indicating that resistance is tumor microenvironment-driven. Phosphatidylinositol 3-kinase (PI3K) pathway activity was elevated in recurrent GBM, driven by macrophage-derived insulin-like growth factor (IGF-1) and tumor cell IGF-1 receptor (IGF-1R). Combining IGF-1R or PI3K blockade with CSF-1R inhibition in recurrent tumors significantly prolonged overall survival. Our findings thus reveal a potential therapeutic approach for treating resistance to CSF-1R inhibitors. PMID:27199435

  15. The Hsp70 inhibiting peptide aptamer A17 potentiates radiosensitization of tumor cells by Hsp90 inhibition.

    PubMed

    Schilling, Daniela; Garrido, Carmen; Combs, Stephanie E; Multhoff, Gabriele

    2017-04-01

    The inhibition of heat shock protein 90 (Hsp90) is a promising strategy to increase the radiosensitivity of tumor cells. However, Hsp90 inhibition induces the expression of Hsp70 which is a prominent cytoprotective protein. Therefore, dual targeting of Hsp70 and Hsp90 might be beneficial to increase the radiosensitivity of tumor cells. Hsp70 inhibiting peptide aptamers have been shown to increase the sensitivity of tumor cells to apoptosis induced by different anticancer drugs. Herein, we studied the radiosensitizing activity of the Hsp70 inhibiting peptide aptamer A17 in combination with the Hsp90 inhibitor NVP-AUY922. Whereas A17 significantly increased apoptosis induction by NVP-AUY922 it did not significantly affect the radiosensitivity of human lung and breast cancer cells. However, Hsp70 inhibition by the aptamer A17 potentiated the radiosensitizing effects of the Hsp90 inhibitor NVP-AUY922. Mechanistically we speculate that an increased number of DNA double strand breaks and an enhanced G2/M arrest might be responsible for the increased radiosensitization in A17 expressing tumor cells. Therefore, the simultaneous inhibition of Hsp90 and Hsp70 combined with radiotherapy might provide a promising anti-cancer strategy.

  16. Combining radiation with autophagy inhibition enhances suppression of tumor growth and angiogenesis in esophageal cancer

    PubMed Central

    CHEN, YONGSHUN; LI, XIAOHONG; GUO, LEIMING; WU, XIAOYUAN; HE, CHUNYU; ZHANG, SONG; XIAO, YANJING; YANG, YUANYUAN; HAO, DAXUAN

    2015-01-01

    Radiotherapy is an effective treatment for esophageal cancer; however, tumor resistance to radiation remains a major biological problem. The present study aimed to investigate whether inhibition of autophagy may decrease overall tumor resistance to radiation. The effects of the autophagy inhibitor 3-methyladenine (3-MA) on radiosensitivity were tested in the EC9706 human esophageal squamous cell carcinoma cell line by colony formation assay. Furthermore, the synergistic cytotoxic effects of 3-MA and radiation were assessed in a tumor xenograft model in nude mice. Mechanistic studies were performed using flow cytometry, immunohistochemistry and western blot analysis. The results of the present study demonstrated that radiation induced an accumulation of autophagosomes and 3-MA effectively inhibited radiation-induced autophagy. Inhibition of autophagy was shown to significantly increase the radiosensitivity of the tumors in vitro and in vivo. The enhancement ratio of sensitization in EC9706 cells was 1.76 when the cells were treated with 10 mM 3-MA, alongside ionizing radiation. In addition, autophagy inhibition increased apoptosis and reduced tumor cell proliferation. The combination of radiation and autophagy inhibition resulted in a significant reduction in tumor volume and vasculature in the murine model. The present study demonstrated in vitro and in vivo that radiation-induced autophagy has a protective effect against cell death, and inhibition of autophagy is able to enhance the radiosensitivity of esophageal squamous cell carcinoma. PMID:25891159

  17. Tumor Vascular Changes Mediated by Inhibition of Oncogenic Signaling

    PubMed Central

    Qayum, Naseer; Muschel, Ruth J.; Im, Jae Hong; Balathasan, Lukxmi; Koch, Cameron J.; Patel, Sonal; McKenna, W. Gillies; Bernhard, Eric J.

    2009-01-01

    Many inhibitors of the EGFR-RAS-PI3 kinase-AKT signaling pathway are in clinical use or under development for cancer therapy. Here we show that treatment of mice bearing human tumor xenografts with inhibitors that block EGFR, RAS, PI3 kinase or AKT resulted in prolonged and durable enhancement of tumor vascular flow, perfusion and decreased tumor hypoxia. The vessels in the treated tumors had decreased tortuosity and increased internodal length accounting for the functional alterations. Inhibition of tumor growth cannot account for these results as the drugs were given at doses that did not alter tumor growth. The tumor cell itself was an essential target as HT1080 tumors that lack EGFR did not respond to an EGFR inhibitor, but did respond with vascular alterations to RAS or PI3 Kinase inhibition. We extended these observations to spontaneously arising tumors in MMTV-neu mice. These tumors also responded to PI3 kinase inhibition with decreased tumor hypoxia, increased vascular flow and morphological alterations of their vessels including increased vascular maturity and acquisition of pericyte markers. These changes are similar to the vascular normalization that has been described after anti-angiogenic treatment of xenografts. One difficulty in the use of vascular normalization as a therapeutic strategy has been its limited duration. In contrast, blocking tumor cell RAS-PI3K-AKT signaling led to persistent vascular changes that might be incorporated into clinical strategies based on improvement of vascular flow or decreased hypoxia. These results indicate that vascular alterations must be considered as a consequence of signaling inhibition in cancer therapy. PMID:19622766

  18. Bee venom inhibits growth of human cervical tumors in mice

    PubMed Central

    Kim, Tae Myoung; Jung, Yu Yeon; Park, Mi Hee; Oh, Sang Hyun; Yun, Hye Seok; Jun, Hyung Ok; Yoo, Hwan Soo; Han, Sang-Bae; Lee, Ung Soo; Yoon, Joo Hee; Song, Min Jong; Hong, Jin Tae

    2015-01-01

    We studied whether bee venom (BV) inhibits cervical tumor growth through enhancement of death receptor (DR) expressions and inactivation of nuclear factor kappa B (NF-κB) in mice. In vivo study showed that BV (1 mg/kg) inhibited tumor growth. Similar inhibitory effects of BV on cancer growth in primary human cervical cancer cells were also found. BV (1–5 μg/ml) also inhibited the growth of cancer cells, Ca Ski and C33Aby the induction of apoptotic cell death in a dose dependent manner. Agreed with cancer cell growth inhibition, expression of death receptors; FAS, DR3 and DR6, and DR downstream pro-apoptotic proteins including caspase-3 and Bax was concomitantly increased, but the NF-κB activity and the expression of Bcl-2 were inhibited by treatment with BV in tumor mice, human cancer cell and human tumor samples as well as cultured cancer cells. In addition, deletion of FAS, DR3 and DR6 by small interfering RNA significantly reversed BV-induced cell growth inhibitory effects as well as NF-κB inactivation. These results suggest that BV inhibits cervical tumor growth through enhancement of FAS, DR3 and DR6 expression via inhibition of NF-κB pathway. PMID:25730901

  19. PARP Inhibition Restores Extrinsic Apoptotic Sensitivity in Glioblastoma

    PubMed Central

    Karpel-Massler, Georg; Pareja, Fresia; Aimé, Pascaline; Shu, Chang; Chau, Lily; Westhoff, Mike-Andrew; Halatsch, Marc-Eric; Crary, John F.; Canoll, Peter; Siegelin, Markus D.

    2014-01-01

    Background Resistance to apoptosis is a paramount issue in the treatment of Glioblastoma (GBM). We show that targeting PARP by the small molecule inhibitors, Olaparib (AZD-2281) or PJ34, reduces proliferation and lowers the apoptotic threshold of GBM cells in vitro and in vivo. Methods The sensitizing effects of PARP inhibition on TRAIL-mediated apoptosis and potential toxicity were analyzed using viability assays and flow cytometry in established GBM cell lines, low-passage neurospheres and astrocytes in vitro. Molecular analyses included western blots and gene silencing. In vivo, effects on tumor growth were examined in a murine subcutaneous xenograft model. Results The combination treatment of PARP inhibitors and TRAIL led to an increased cell death with activation of caspases and inhibition of formation of neurospheres when compared to single-agent treatment. Mechanistically, pharmacological PARP inhibition elicited a nuclear stress response with up-regulation of down-stream DNA-stress response proteins, e.g., CCAAT enhancer binding protein (C/EBP) homology protein (CHOP). Furthermore, Olaparib and PJ34 increased protein levels of DR5 in a concentration and time-dependent manner. In turn, siRNA-mediated suppression of DR5 mitigated the effects of TRAIL/PARP inhibitor-mediated apoptosis. In addition, suppression of PARP-1 levels enhanced TRAIL-mediated apoptosis in malignant glioma cells. Treatment of human astrocytes with the combination of TRAIL/PARP inhibitors did not cause toxicity. Finally, the combination treatment of TRAIL and PJ34 significantly reduced tumor growth in vivo when compared to treatment with each agent alone. Conclusions PARP inhibition represents a promising avenue to overcome apoptotic resistance in GBM. PMID:25531448

  20. Statistical inference for tumor growth inhibition T/C ratio.

    PubMed

    Wu, Jianrong

    2010-09-01

    The tumor growth inhibition T/C ratio is commonly used to quantify treatment effects in drug screening tumor xenograft experiments. The T/C ratio is converted to an antitumor activity rating using an arbitrary cutoff point and often without any formal statistical inference. Here, we applied a nonparametric bootstrap method and a small sample likelihood ratio statistic to make a statistical inference of the T/C ratio, including both hypothesis testing and a confidence interval estimate. Furthermore, sample size and power are also discussed for statistical design of tumor xenograft experiments. Tumor xenograft data from an actual experiment were analyzed to illustrate the application.

  1. Dll4 activation of Notch signaling reduces tumor vascularity and inhibits tumor growth

    PubMed Central

    Williams, Cassin Kimmel; la Luz Sierra, Maria de; Bernardo, Marcelino; McCormick, Peter J.; Maric, Dragan; Regino, Celeste; Choyke, Peter; Tosato, Giovanna

    2008-01-01

    Gene targeting experiments have shown that Delta-like 4 (Dll4) is a vascular-specific Notch ligand critical to normal vascular development. Recent studies have demonstrated that inhibition of Dll4/Notch signaling in tumor-bearing mice resulted in excessive, yet nonproductive tumor neovascularization and unexpectedly reduced tumor growth. Because nonfunctional blood vessels have the potential to normalize, we explored the alternative approach of stimulating Notch signaling in the tumor vasculature to inhibit tumor growth. Here we show that retrovirus-induced over-expression of Dll4 in tumor cells activates Notch signaling in cocultured endothelial cells and limits vascular endothelial growth factor (VEGF)–induced endothelial cell growth. Tumors produced in mice by injection of human and murine tumor cells transduced with Dll4 were significantly smaller, less vascularized and more hypoxic than controls, and displayed evidence of Notch activation. In addition, tumor blood perfusion was reduced as documented by vascular imaging. These results demonstrate that Notch activation in the tumor microenvironment reduces tumor neovascularization and blood perfusion, and suggest that Dll4-induced Notch activation may represent an effective therapeutic approach for the treatment of solid tumors. PMID:18577711

  2. Lithium inhibits tumor lymphangiogenesis and metastasis through the inhibition of TGFBIp expression in cancer cells.

    PubMed

    Maeng, Yong-Sun; Lee, Rina; Lee, Boram; Choi, Seung-Il; Kim, Eung Kweon

    2016-02-09

    Metastasis is the main cause of mortality in cancer patients. Although there are many anti-cancer drugs targeting tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression; in particular, lymphangiogenesis is pivotal for metastasis in cancer. Here we report that lithium inhibits colon cancer metastasis by blocking lymphangiogenesis. Lithium reduces the expression of transforming growth factor-β-induced protein (TGFBIp) in colon cancer cells by inhibiting Smad3 phosphorylation via GSK3β inactivation. Moreover, lithium inhibits lymphatic endothelial cell migration, which is increased upon TGFBIp expression in tumor cells. Lithium had no significant effect on SW620 tumor growth in vitro and in vivo; however, it inhibited lymphangiogenesis in tumors. In tumor xenografts model, lithium was found to prevent metastasis to the lungs, liver, and lymph nodes by inhibiting TGFBIp-induced tumor lymphangiogenesis. Collectively, our findings demonstrate a novel role of lithium in the inhibition of colon cancer metastasis by blocking TGFBIp expression, and thereby TGFBIp-induced lymphangiogenesis, in primary tumors.

  3. Lithium inhibits tumor lymphangiogenesis and metastasis through the inhibition of TGFBIp expression in cancer cells

    PubMed Central

    Maeng, Yong-Sun; Lee, Rina; Lee, Boram; Choi, Seung-il; Kim, Eung Kweon

    2016-01-01

    Metastasis is the main cause of mortality in cancer patients. Although there are many anti-cancer drugs targeting tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression; in particular, lymphangiogenesis is pivotal for metastasis in cancer. Here we report that lithium inhibits colon cancer metastasis by blocking lymphangiogenesis. Lithium reduces the expression of transforming growth factor-β-induced protein (TGFBIp) in colon cancer cells by inhibiting Smad3 phosphorylation via GSK3β inactivation. Moreover, lithium inhibits lymphatic endothelial cell migration, which is increased upon TGFBIp expression in tumor cells. Lithium had no significant effect on SW620 tumor growth in vitro and in vivo; however, it inhibited lymphangiogenesis in tumors. In tumor xenografts model, lithium was found to prevent metastasis to the lungs, liver, and lymph nodes by inhibiting TGFBIp-induced tumor lymphangiogenesis. Collectively, our findings demonstrate a novel role of lithium in the inhibition of colon cancer metastasis by blocking TGFBIp expression, and thereby TGFBIp-induced lymphangiogenesis, in primary tumors. PMID:26857144

  4. Depleting Tumor-NQO1 Potentiates Anoikis and Inhibits Growth of NSCLC.

    PubMed

    Madajewski, Brian; Boatman, Michael A; Chakrabarti, Gaurab; Boothman, David A; Bey, Erik A

    2016-01-01

    The fundamental role that NAD(P)H/quinone oxidoreductase 1 (NQO1) plays, in normal cells, as a cytoprotective enzyme guarding against stress induced by reactive oxygen species (ROS) is well documented. However, what is not known is whether the observed overexpression of NQO1 in neoplastic cells contributes to their survival. The current study discovered that depleting NQO1 expression in A549 and H292 lung adenocarcinoma cells caused an increase in ROS formation, inhibited anchorage-independent growth, increased anoikis sensitization, and decreased three-dimensional tumor spheroid invasion. These in vivo data further implicate tumor-NQO1 expression in a protumor survival role, because its depletion suppressed cell proliferation and decreased lung tumor xenograft growth. Finally, these data reveal an exploitable link between tumor-NQO1 expression and the survival of lung tumors because NQO1 depletion significantly decreased the percentage of ALDH((high)) cancer cells within the tumor population. Loss of tumor-NQO1 expression inhibits tumor growth and suggests that novel therapeutics directed at tumor-NQO1 may have clinical benefit. ©2015 American Association for Cancer Research.

  5. Salmonella overcomes tumor immune tolerance by inhibition of tumor indoleamine 2, 3-dioxygenase 1 expression.

    PubMed

    Kuan, Yu-Diao; Lee, Che-Hsin

    2016-01-05

    Over the past decades, Salmonella has been proven capable of inhibiting tumor growth. It can specifically target tumors and due to its facultative anaerobic property, can be more penetrative than other drug therapies. However, the molecular mechanism by which Salmonella inhibits tumor growth is still incompletely known. The antitumor therapeutic effect mediated by Salmonella is associated with an inflammatory immune response at the tumor site and a T cell-dependent immune response. Many tumors have been proven to have a high expression of indoleamine 2, 3-dioxygenase 1 (IDO), which is a rate-limiting enzyme that catalyzes tryptophan to kynurenine, thus causing immune tolerance within the tumor microenvironment. With decreased expression of IDO, increased immune response can be observed, which might be helpful when developing cancer immunotherapy. The expression of IDO was decreased after tumor cells were infected with Salmonella. In addition, Western blot analysis showed that the expression levels of phospho-protein kinase B (P-AKT), phospho-mammalian targets of rapamycin (P-mTOR), and phospho-p70 ribosomal s6 kinase (P-p70s6K) in tumor cells were decreased after Salmonella infection. In conclusion, our results indicate that Salmonella inhibits IDO expression and plays a crucial role in anti-tumor therapy, which might be a promising strategy combined with other cancer treatments.

  6. Dietary rice bran component γ-oryzanol inhibits tumor growth in tumor-bearing mice.

    PubMed

    Kim, Sung Phil; Kang, Mi Young; Nam, Seok Hyun; Friedman, Mendel

    2012-06-01

    We investigated the effects of rice bran and components on tumor growth in mice. Mice fed standard diets supplemented with rice bran, γ-oryzanol, Ricetrienol®, ferulic acid, or phytic acid for 2 weeks were inoculated with CT-26 colon cancer cells and fed the same diet for two additional weeks. Tumor mass was significantly lower in the γ-oryzanol and less so in the phytic acid group. Tumor inhibition was associated with the following biomarkers: increases in cytolytic activity of splenic natural killer (NK) cells; partial restoration of nitric oxide production and phagocytosis in peritoneal macrophages increases in released the pro-inflammatory cytokines tumor necrosis factor-α, IL-1β, and IL-6 from macrophages; and reductions in the number of blood vessels inside the tumor. Pro-angiogenic biomarkers vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), and 5-lipoxygenase-5 (5-LOX) were also significantly reduced in mRNA and protein expression by tumor genes. ELISA of tumor cells confirmed reduced expression of COX-2 and 5-LOX up to 30%. Reduced COX-2 and 5-LOX expression downregulated VEGF and inhibited neoangiogenesis inside the tumors. Induction of NK activity, activation of macrophages, and inhibition of angiogenesis seem to contribute to the inhibitory mechanism of tumor regression by γ-oryzanol. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. High rates of chromosome missegregation suppress tumor progression but do not inhibit tumor initiation

    PubMed Central

    Zasadil, Lauren M.; Britigan, Eric M. C.; Ryan, Sean D.; Kaur, Charanjeet; Guckenberger, David J.; Beebe, David J.; Moser, Amy R.; Weaver, Beth A.

    2016-01-01

    Aneuploidy, an abnormal chromosome number that deviates from a multiple of the haploid, has been recognized as a common feature of cancers for >100 yr. Previously, we showed that the rate of chromosome missegregation/chromosomal instability (CIN) determines the effect of aneuploidy on tumors; whereas low rates of CIN are weakly tumor promoting, higher rates of CIN cause cell death and tumor suppression. However, whether high CIN inhibits tumor initiation or suppresses the growth and progression of already initiated tumors remained unclear. We tested this using the ApcMin/+ mouse intestinal tumor model, in which effects on tumor initiation versus progression can be discriminated. ApcMin/+ cells exhibit low CIN, and we generated high CIN by reducing expression of the kinesin-like mitotic motor protein CENP-E. CENP-E+/−;ApcMin/+ doubly heterozygous cells had higher rates of chromosome missegregation than singly heterozygous cells, resulting in increased cell death and a substantial reduction in tumor progression compared with ApcMin/+ animals. Intestinal organoid studies confirmed that high CIN does not inhibit tumor cell initiation but does inhibit subsequent cell growth. These findings support the conclusion that increasing the rate of chromosome missegregation could serve as a successful chemotherapeutic strategy. PMID:27146113

  8. Salmonella overcomes tumor immune tolerance by inhibition of tumor indoleamine 2, 3-dioxygenase 1 expression

    PubMed Central

    Kuan, Yu-Diao; Lee, Che-Hsin

    2016-01-01

    Over the past decades, Salmonella has been proven capable of inhibiting tumor growth. It can specifically target tumors and due to its facultative anaerobic property, can be more penetrative than other drug therapies. However, the molecular mechanism by which Salmonella inhibits tumor growth is still incompletely known. The antitumor therapeutic effect mediated by Salmonella is associated with an inflammatory immune response at the tumor site and a T cell-dependent immune response. Many tumors have been proven to have a high expression of indoleamine 2, 3-dioxygenase 1 (IDO), which is a rate-limiting enzyme that catalyzes tryptophan to kynurenine, thus causing immune tolerance within the tumor microenvironment. With decreased expression of IDO, increased immune response can be observed, which might be helpful when developing cancer immunotherapy. The expression of IDO was decreased after tumor cells were infected with Salmonella. In addition, Western blot analysis showed that the expression levels of phospho-protein kinase B (P-AKT), phospho-mammalian targets of rapamycin (P-mTOR), and phospho-p70 ribosomal s6 kinase (P-p70s6K) in tumor cells were decreased after Salmonella infection. In conclusion, our results indicate that Salmonella inhibits IDO expression and plays a crucial role in anti-tumor therapy, which might be a promising strategy combined with other cancer treatments. PMID:26517244

  9. Nitric oxide-mediated sensitization of resistant tumor cells to apoptosis by chemo-immunotherapeutics☆

    PubMed Central

    Bonavida, Benjamin; Garban, Hermes

    2015-01-01

    The generation of NO by the various NO synthases in normal and malignant tissues is manifested by various biological effects that are involved in the regulation of cell survival, differentiation and cell death. The role of NO in the cytotoxic immune response was first revealed by demonstrating the induction of iNOS in target cells by immune cytokines (e.g. IFN-γ, IL-1, TNF-α, etc.) and resulting in the sensitization of resistant tumor cells to death ligands-induced apoptosis. Endogenous/exogenous NO mediated its immune sensitizing effect by inhibiting NF-κΒ activity and downstream, inactivating the repressor transcription factor YY1, which inhibited both Fas and DR5 expressions. In addition, NO-mediated inhibition of NF-κΒ activity and inhibition downstream of its anti-apoptotic gene targets sensitized the tumor cells to apoptosis by chemotherapeutic drugs. We have identified in tumor cells a dysregulated pro-survival/anti-apoptotic loop consisting of NF-κB/Snail/YY1/RKIP/PTEN and its modification by NO was responsible, in large, for the reversal of chemo and immune resistance and sensitization to apoptotic mechanisms by cytotoxic agents. Moreover, tumor cells treated with exogenous NO donors resulted in the inhibition of NF-κΒ activity via S-nitrosylation of p50 and p65, inhibition of Snail (NF-κΒ target gene), inhibition of transcription repression by S-nitrosylation of YY1 and subsequent inhibition of epithelial–mesenchymal transition (EMT), induction of RKIP (inhibition of the transcription repressor Snail), and induction of PTEN (inhibition of the repressors Snail and YY1). Further, each gene product modified by NO in the loop was involved in chemo-immunosensitization. These above findings demonstrated that NO donors interference in the regulatory circuitry result in chemo-immunosensitization and inhibition of EMT. Overall, these observations suggest the potential anti-tumor therapeutic effect of NO donors in combination with subtoxic chemo

  10. MGMT Inhibition Restores ERα Functional Sensitivity to Antiestrogen Therapy

    PubMed Central

    Bobustuc, George C; Smith, Joshua S; Maddipatla, Sreeram; Jeudy, Sheila; Limaye, Arati; Isley, Beth; Caparas, Maria-Lourdes M; Constantino, Susan M; Shah, Nikita; Baker, Cheryl H; Srivenugopal, Kalkunte S; Baidas, Said; Konduri, Santhi D

    2012-01-01

    Antiestrogen therapy resistance remains a huge stumbling block in the treatment of breast cancer. We have found significant elevation of O6 methylguanine DNA methyl transferase (MGMT) expression in a small sample of consecutive patients who have failed tamoxifen treatment. Here, we show that tamoxifen resistance is accompanied by upregulation of MGMT. Further we show that administration of the MGMT inhibitor, O6-benzylguanine (BG), at nontoxic doses, leads to restoration of a favorable estrogen receptor alpha (ERα) phosphorylation phenotype (high p-ERα Ser167/low p-ERα Ser118), which has been reported to correlate with sensitivity to endocrine therapy and improved survival. We also show BG to be a dual inhibitor of MGMT and ERα. In tamoxifen-resistant breast cancer cells, BG alone or in combination with antiestrogen (tamoxifen [TAM]/ICI 182,780 [fulvestrant, Faslodex]) therapy enhances p53 upregulated modulator of apoptosis (PUMA) expression, cytochrome C release and poly (ADP-ribose) polymerase (PARP) cleavage, all indicative of apoptosis. In addition, BG increases the expression of p21cip1/waf1. We also show that BG, alone or in combination therapy, curtails the growth of tamoxifen-resistant breast cancer in vitro and in vivo. In tamoxifen-resistant MCF7 breast cancer xenografts, BG alone or in combination treatment causes significant delay in tumor growth. Immunohistochemistry confirms that BG increases p21cip1/waf1 and p-ERα Ser167 expression and inhibits MGMT, ERα, p-ERα Ser118 and ki-67 expression. Collectively, our results suggest that MGMT inhibition leads to growth inhibition of tamoxifen-resistant breast cancer in vitro and in vivo and resensitizes tamoxifen-resistant breast cancer cells to antiestrogen therapy. These findings suggest that MGMT inhibition may provide a novel therapeutic strategy for overcoming antiestrogen resistance. PMID:22549111

  11. Alpha1-antitrypsin inhibits angiogenesis and tumor growth.

    PubMed

    Huang, Hanhua; Campbell, Steven C; Nelius, Thomas; Bedford, Dhugal F; Veliceasa, Dorina; Bouck, Noel P; Volpert, Olga V

    2004-12-20

    Disturbances of the ratio between angiogenic inducers and inhibitors in tumor microenvironment are the driving force behind angiogenic switch critical for tumor progression. Angiogenic inhibitors may vary depending on organismal age and the tissue of origin. We showed that alpha(1)-antitrypsin (AAT), a serine protease inhibitor (serpin) is an inhibitor of angiogenesis, which induced apoptosis and inhibited chemotaxis of endothelial cells. S- and Z-type mutations that cause abnormal folding and defective serpin activity abrogated AAT antiangiogenic activity. Removal of the C-terminal reactive site loop had no effect on its angiostatic activity. Both native AAT and AAT truncated on C-terminus (AATDelta) inhibited neovascularization in the rat cornea and delayed the growth of subcutaneous tumors in mice. Treatment with native AAT and truncated AATDelta, but not control vehicle reduced tumor microvessel density, while increasing apoptosis within tumor endothelium. Comparative analysis of the human tumors and normal tissues of origin showed correlation between reduced local alpha(1)-antitrypsin expression and more aggressive tumor growth.

  12. Metformin Inhibits Skin Tumor Promotion in Overweight and Obese Mice

    PubMed Central

    Checkley, L. Allyson; Rho, Okkyung; Angel, Joe M.; Cho, Jiyoon; Blando, Jorge; Beltran, Linda; Hursting, Stephen D.; DiGiovanni, John

    2014-01-01

    In the present study, the ability of metformin to inhibit skin tumor promotion by 12-O- tetradecanoylphorbol-13-acetate (TPA) was analyzed in mice maintained on either an overweight control diet or an obesity inducing diet. Rapamycin was included for comparison, and a combination of metformin and rapamycin was also evaluated. Metformin (given in the drinking water) and rapamycin (given topically) inhibited development of both papillomas and squamous cell carcinomas in overweight and obese mice in a dose-dependent manner. A low dose combination of these two compounds displayed an additive inhibitory effect on tumor development. Metformin treatment also reduced the size of papillomas. Interestingly, all treatments appeared to be at least as effective for inhibiting tumor formation in obese mice and both metformin and rapamycin were more effective at reducing tumor size in obese mice compared to overweight control mice. The effect of metformin on skin tumor development was associated with a significant reduction in TPA-induced epidermal hyperproliferation. Furthermore, treatment with metformin led to activation of epidermal AMPK and attenuated signaling through mTORC1 and p70S6K. Combinations of metformin and rapamycin were more effective at blocking epidermal mTORC1 signaling induced by TPA consistent with the greater inhibitory effect on skin tumor promotion. Collectively, the current data demonstrate that metformin given in the drinking water effectively inhibited skin tumor promotion in both overweight and obese mice and that the mechanism involves activation of epidermal AMPK and attenuated signaling downstream of mTORC1. PMID:24196830

  13. Sclareol modulates the Treg intra-tumoral infiltrated cell and inhibits tumor growth in vivo.

    PubMed

    Noori, Shokoofe; Hassan, Zuhair M; Mohammadi, Mehdi; Habibi, Zohre; Sohrabi, Nooshin; Bayanolhagh, Saeed

    2010-01-01

    A regulatory or suppressor T cell is functionally defined as a T cell that inhibits an immune response by influencing the activity of another cell type. On the other hand, Th1 cells express IFN-gamma and mediate cellular immunity. Sclareol exhibits growth inhibition and cytotoxic activity against a variety of human cancer cell lines. In the first set of experiments, Sclareol was isolated from the plant Salvia sclarea and our study assessed the immuno-therapeutic effectiveness of Sclareol by direct intra-tumoral injection. Secondly, several immunological parameters such as splenocytes proliferation, intra-tumor CD4+CD25+Foxp3+ Treg cells, IFN-gamma and IL-4 secretion and tumor size were assessed to evaluate the anti-tumoral immune response. By all means, the findings confirmed that the activity of Sclareol could reduce the tumor growth in vivo against breast cancer. Copyright (c) 2010. Published by Elsevier Inc.

  14. Bicarbonate increases tumor pH and inhibits spontaneous metastases.

    PubMed

    Robey, Ian F; Baggett, Brenda K; Kirkpatrick, Nathaniel D; Roe, Denise J; Dosescu, Julie; Sloane, Bonnie F; Hashim, Arig Ibrahim; Morse, David L; Raghunand, Natarajan; Gatenby, Robert A; Gillies, Robert J

    2009-03-15

    The external pH of solid tumors is acidic as a consequence of increased metabolism of glucose and poor perfusion. Acid pH has been shown to stimulate tumor cell invasion and metastasis in vitro and in cells before tail vein injection in vivo. The present study investigates whether inhibition of this tumor acidity will reduce the incidence of in vivo metastases. Here, we show that oral NaHCO(3) selectively increased the pH of tumors and reduced the formation of spontaneous metastases in mouse models of metastatic breast cancer. This treatment regimen was shown to significantly increase the extracellular pH, but not the intracellular pH, of tumors by (31)P magnetic resonance spectroscopy and the export of acid from growing tumors by fluorescence microscopy of tumors grown in window chambers. NaHCO(3) therapy also reduced the rate of lymph node involvement, yet did not affect the levels of circulating tumor cells, suggesting that reduced organ metastases were not due to increased intravasation. In contrast, NaHCO(3) therapy significantly reduced the formation of hepatic metastases following intrasplenic injection, suggesting that it did inhibit extravasation and colonization. In tail vein injections of alternative cancer models, bicarbonate had mixed results, inhibiting the formation of metastases from PC3M prostate cancer cells, but not those of B16 melanoma. Although the mechanism of this therapy is not known with certainty, low pH was shown to increase the release of active cathepsin B, an important matrix remodeling protease.

  15. Bicarbonate Increases Tumor pH and Inhibits Spontaneous Metastases

    PubMed Central

    Robey, Ian F.; Baggett, Brenda K.; Kirkpatrick, Nathaniel D.; Roe, Denise J.; Dosescu, Julie; Sloane, Bonnie F.; Hashim, Arig Ibrahim; Morse, David L.; Raghunand, Natarajan; Gatenby, Robert A.; Gillies, Robert J.

    2010-01-01

    The external pH of solid tumors is acidic as a consequence of increased metabolism of glucose and poor perfusion. Acid pH has been shown to stimulate tumor cell invasion and metastasis in vitro and in cells before tail vein injection in vivo. The present study investigates whether inhibition of this tumor acidity will reduce the incidence of in vivo metastases. Here, we show that oral NaHCO3 selectively increased the pH of tumors and reduced the formation of spontaneous metastases in mouse models of metastatic breast cancer. This treatment regimen was shown to significantly increase the extracellular pH, but not the intracellular pH, of tumors by 31P magnetic resonance spectroscopy and the export of acid from growing tumors by fluorescence microscopy of tumors grown in window chambers. NaHCO3 therapy also reduced the rate of lymph node involvement, yet did not affect the levels of circulating tumor cells, suggesting that reduced organ metastases were not due to increased intravasation. In contrast, NaHCO3 therapy significantly reduced the formation of hepatic metastases following intrasplenic injection, suggesting that it did inhibit extravasation and colonization. In tail vein injections of alternative cancer models, bicarbonate had mixed results, inhibiting the formation of metastases from PC3M prostate cancer cells, but not those of B16 melanoma. Although the mechanism of this therapy is not known with certainty, low pH was shown to increase the release of active cathepsin B, an important matrix remodeling protease. PMID:19276390

  16. Correlation between the sensitivity of tumors to treatment with CZ48 and local concentrations of the active metabolite CPT within the tumors

    PubMed Central

    LIU, XING; CAO, ZHISONG; MENDOZA, JOHN; VARDEMAN, DANA; GIOVANELLA, BEPPINO

    2013-01-01

    Crystalline camptothecin-20-O-propionate hydrate (CZ48) is an esterification product from the reaction of natural camptothecin with propionic anhydride. CZ48 has been tested against 29 human tumor lines grown in nude mice as xenografts. Of the tested tumor lines, 28 were found to be responsive to CZ48, by regression or significant inhibition. The total response rate was 97%. However, the effective dose required to achieve the positive response varied from 100 to 2000 mg/kg/day depending on the tumor type. Thus, the sensitivity of tumors to CZ48 treatment varied from tumor to tumor. The most sensitive CLO-breast carcinoma achieved regression when treated with 100 mg/kg/day, while PC3-prostate carcinoma required as high as 1000 mg/kg/day to achieve a definitive response. To determine the reason for these differences in sensitivities among the tumors, we treated 9 human xenografts grown in nude mice with 1000 mg/kg/day CZ48 until saturation and measured the local concentrations of the parental CZ48 as well as the corresponding metabolite camptothecin (CPT) in the tumors with the established high-performance liquid chromatography procedure. Results showed that the sensitivities of these tumors to CZ48 treatment were not affected by local concentrations of the active metabolite CPT in the tumors, but instead by the types of tumors. PMID:24648919

  17. Targeting Aurora Kinase A enhances radiation sensitivity of atypical teratoid rhabdoid tumor cells.

    PubMed

    Venkataraman, Sujatha; Alimova, Irina; Tello, Tiffany; Harris, Peter S; Knipstein, Jeffrey A; Donson, Andrew M; Foreman, Nicholas K; Liu, Arthur K; Vibhakar, Rajeev

    2012-05-01

    Atypical teratoid/rhabdoid tumors (ATRT) are rare, highly malignant, embryonal CNS tumors with a poor prognosis. Therapy relies on highly toxic chemotherapy and radiotherapy. To improve outcomes and decrease morbidity, more targeted therapy is required. Gene expression analysis revealed elevated expression of multiple kinases in ATRT tissues. Aurora Kinase A was one of the candidate kinases. The objective of this study was to evaluate the impact of Aurora Kinase A inhibition in ATRT cell lines. Our analysis revealed that inhibition of Aurora Kinase A induces cell death in ATRT cells and the small molecule inhibitor MLN 8237 sensitizes these cells to radiation. Furthermore, inhibition of Aurora Kinase A resulted in decreased activity of pro-proliferative signaling pathways. These data indicate that inhibition of Aurora Kinase A is a promising small molecule target for ATRT therapy.

  18. PPARγ ligands inhibit primary tumor growth and metastasis by inhibiting angiogenesis

    PubMed Central

    Panigrahy, Dipak; Singer, Samuel; Shen, Lucy Q.; Butterfield, Catherine E.; Freedman, Deborah A.; Chen, Emy J.; Moses, Marsha A.; Kilroy, Susan; Duensing, Stefan; Fletcher, Christopher; Fletcher, Jonathan A.; Hlatky, Lynn; Hahnfeldt, Philip; Folkman, Judah; Kaipainen, Arja

    2002-01-01

    Several drugs approved for a variety of indications have been shown to exhibit antiangiogenic effects. Our study focuses on the PPARγ ligand rosiglitazone, a compound widely used in the treatment of type 2 diabetes. We demonstrate, for the first time to our knowledge, that PPARγ is highly expressed in tumor endothelium and is activated by rosiglitazone in cultured endothelial cells. Furthermore, we show that rosiglitazone suppresses primary tumor growth and metastasis by both direct and indirect antiangiogenic effects. Rosiglitazone inhibits bovine capillary endothelial cell but not tumor cell proliferation at low doses in vitro and decreases VEGF production by tumor cells. In our in vivo studies, rosiglitazone suppresses angiogenesis in the chick chorioallantoic membrane, in the avascular cornea, and in a variety of primary tumors. These results suggest that PPARγ ligands may be useful in treating angiogenic diseases such as cancer by inhibiting angiogenesis. PMID:12370270

  19. Inhibition of metastasis by inhibition of tumor-derived CCL5.

    PubMed

    Stormes, Kerry A; Lemken, Charles A; Lepre, James V; Marinucci, Michelle N; Kurt, Robert A

    2005-01-01

    To determine whether tumor-derived CCL5 contributes to the metastatic potential of murine mammary carcinoma, we used the 4T1 tumor which spontaneously metastasizes and constitutively produces CCL5. Mice bearing 4T1 that expressed less CCL5 had significantly fewer lung and liver metastasis. The decrease in tumor-derived CCL5 also correlated with decreased cathepsin L, MMP-2, MMP-3, MMP-10 and MMP-17 gene expression. Thus, inhibition of tumor-derived CCL5 can impact the metastatic capability of 4T1 and may do so by modulating protease expression.

  20. Tumor-Penetrating iRGD Peptide Inhibits Metastasis

    PubMed Central

    Sugahara, Kazuki N.; Braun, Gary B.; de Mendoza, Tatiana Hurtado; Kotamraju, Venkata Ramana; French, Randall P.; Lowy, Andrew M.; Teesalu, Tambet; Ruoslahti, Erkki

    2014-01-01

    Tumor-specific tissue-penetrating peptides deliver drugs into extravascular tumor tissue by increasing tumor vascular permeability through interaction with neuropilin (NRP). Here we report that a prototypic tumor-penetrating peptide iRGD (amino acid sequence: CRGDKGPDC) potently inhibits spontaneous metastasis in mice. The anti-metastatic effect was mediated by the NRP-binding RXXK peptide motif (CendR motif), and not by the integrin-binding RGD motif. iRGD inhibited migration of tumor cells and caused chemorepulsion in vitro in a CendR- and NRP-1-dependent manner. The peptide induced dramatic collapse of cellular processes and partial cell detachment, resulting in the repellent activity. These effects were prominently displayed when the cells were seeded on fibronectin, suggesting a role of CendR in functional regulation of integrins. The anti-metastatic activity of iRGD may provide a significant additional benefit when this peptide is used for drug delivery to tumors. PMID:25392370

  1. Plumbagin inhibits breast tumor bone metastasis and osteolysis by modulating the tumor-bone microenvironment.

    PubMed

    Li, Z; Xiao, J; Wu, X; Li, W; Yang, Z; Xie, J; Xu, L; Cai, X; Lin, Z; Guo, W; Luo, J; Liu, M

    2012-09-01

    Bone metastasis is a common and serious consequence of breast cancer. Bidirectional interaction between tumor cells and the bone marrow microenvironment drives a so-called 'vicious cycle' that promotes tumor cell malignancy and stimulates osteolysis. Targeting these interactions and pathways in the tumor-bone microenvironment has been an encouraging strategy for bone metastasis therapy. In the present study, we examined the effects of plumbagin on breast cancer bone metastasis. Our data indicated that plumbagin inhibited cancer cell migration and invasion, suppressed the expression of osteoclast-activating factors, altered the cancer cell induced RANKL/OPG ratio in osteoblasts, and blocked both cancer cell- and RANKL-stimulated osteoclastogenesis. In mouse model of bone metastasis, we further demonstrated that plumbagin significantly repressed breast cancer cell metastasis and osteolysis, inhibited cancer cell induced-osteoclastogenesis and the secretion of osteoclast-activating factors in vivo. At the molecular level, we found that plumbagin abrogated RANKL-induced NF-κB and MAPK pathways by blocking RANK association with TRAF6 in osteoclastogenesis, and by inhibiting the expression of osteoclast-activating factors through the suppression of NF-κB activity in breast cancer cells. Taken together, our data demonstrate that plumbagin inhibits breast tumor bone metastasis and osteolysis by modulating the tumor-bone microenvironment and that plumbagin may serve as a novel agent in the treatment of tumor bone metastasis.

  2. Pharmacological inhibition of KIT activates MET signaling in gastrointestinal stromal tumors

    PubMed Central

    Cohen, Noah A.; Zeng, Shan; Seifert, Adrian M.; Kim, Teresa S.; Sorenson, Eric C.; Greer, Jonathan B.; Beckman, Michael J.; Santamaria-Barria, Juan A.; Crawley, Megan H.; Green, Benjamin L.; Rossi, Ferdinand; Besmer, Peter; Antonescu, Cristina R.; DeMatteo, Ronald P.

    2015-01-01

    Gastrointestinal stromal tumors (GIST) are the most common adult sarcomas and the oncogenic driver is usually a KIT or PDGFRA mutation. While GIST are often initially sensitive to imatinib or other tyrosine kinase inhibitors, resistance generally develops necessitating backup strategies for therapy. In this study, we determined that a subset of human GIST specimens that acquired imatinib resistance acquired expression of activated forms of the MET oncogene. MET activation also developed after imatinib therapy in a mouse model of GIST (KitV558del/+ mice), where it was associated with increased tumor hypoxia. MET activation also occurred in imatinib-sensitive human GIST cell lines after imatinib treatment in vitro. MET inhibition by crizotinib or RNA interference was cytotoxic to an imatinib-resistant human GIST cell population. Moreover, combining crizotinib and imatinib was more effective than imatinib alone in imatinib-sensitive GIST models. Lastly, cabozantinib, a dual MET and KIT small molecule inhibitor, was markedly more effective than imatinib in multiple preclinical models of imatinib-sensitive and imatinib-resistant GIST. Collectively, our findings showed that activation of compensatory MET signaling by KIT inhibition may contribute to tumor resistance. Furthermore, our work offered a preclinical proof of concept for MET inhibition by cabozantinib as an effective strategy for GIST treatment. PMID:25836719

  3. Inhibition of de novo Palmitate Synthesis by Fatty Acid Synthase Induces Apoptosis in Tumor Cells by Remodeling Cell Membranes, Inhibiting Signaling Pathways, and Reprogramming Gene Expression.

    PubMed

    Ventura, Richard; Mordec, Kasia; Waszczuk, Joanna; Wang, Zhaoti; Lai, Julie; Fridlib, Marina; Buckley, Douglas; Kemble, George; Heuer, Timothy S

    2015-08-01

    Inhibition of de novo palmitate synthesis via fatty acid synthase (FASN) inhibition provides an unproven approach to cancer therapy with a strong biological rationale. FASN expression increases with tumor progression and associates with chemoresistance, tumor metastasis, and diminished patient survival in numerous tumor types. TVB-3166, an orally-available, reversible, potent, and selective FASN inhibitor induces apoptosis, inhibits anchorage-independent cell growth under lipid-rich conditions, and inhibits in-vivo xenograft tumor growth. Dose-dependent effects are observed between 20-200 nM TVB-3166, which agrees with the IC50 in biochemical FASN and cellular palmitate synthesis assays. Mechanistic studies show that FASN inhibition disrupts lipid raft architecture, inhibits biological pathways such as lipid biosynthesis, PI3K-AKT-mTOR and β-catenin signal transduction, and inhibits expression of oncogenic effectors such as c-Myc; effects that are tumor-cell specific. Our results demonstrate that FASN inhibition has anti-tumor activities in biologically diverse preclinical tumor models and provide mechanistic and pharmacologic evidence that FASN inhibition presents a promising therapeutic strategy for treating a variety of cancers, including those expressing mutant K-Ras, ErbB2, c-Met, and PTEN. The reported findings inform ongoing studies to link mechanisms of action with defined tumor types and advance the discovery of biomarkers supporting development of FASN inhibitors as cancer therapeutics. Fatty acid synthase (FASN) is a vital enzyme in tumor cell biology; the over-expression of FASN is associated with diminished patient prognosis and resistance to many cancer therapies. Our data demonstrate that selective and potent FASN inhibition with TVB-3166 leads to selective death of tumor cells, without significant effect on normal cells, and inhibits in vivo xenograft tumor growth at well-tolerated doses. Candidate biomarkers for selecting tumors highly sensitive

  4. Inhibition of de novo Palmitate Synthesis by Fatty Acid Synthase Induces Apoptosis in Tumor Cells by Remodeling Cell Membranes, Inhibiting Signaling Pathways, and Reprogramming Gene Expression

    PubMed Central

    Ventura, Richard; Mordec, Kasia; Waszczuk, Joanna; Wang, Zhaoti; Lai, Julie; Fridlib, Marina; Buckley, Douglas; Kemble, George; Heuer, Timothy S.

    2015-01-01

    selecting tumors highly sensitive to FASN inhibition are identified. These preclinical data provide mechanistic and pharmacologic evidence that FASN inhibition presents a promising therapeutic strategy for treating a variety of cancers. PMID:26425687

  5. Autophagy inhibition overcomes multiple mechanisms of resistance to BRAF inhibition in brain tumors

    PubMed Central

    Mulcahy Levy, Jean M; Zahedi, Shadi; Griesinger, Andrea M; Morin, Andrew; Davies, Kurtis D; Aisner, Dara L; Kleinschmidt-DeMasters, BK; Fitzwalter, Brent E; Goodall, Megan L; Thorburn, Jacqueline; Amani, Vladimir; Donson, Andrew M; Birks, Diane K; Mirsky, David M; Hankinson, Todd C; Handler, Michael H; Green, Adam L; Vibhakar, Rajeev; Foreman, Nicholas K; Thorburn, Andrew

    2017-01-01

    Kinase inhibitors are effective cancer therapies, but tumors frequently develop resistance. Current strategies to circumvent resistance target the same or parallel pathways. We report here that targeting a completely different process, autophagy, can overcome multiple BRAF inhibitor resistance mechanisms in brain tumors. BRAFV600Emutations occur in many pediatric brain tumors. We previously reported that these tumors are autophagy-dependent and a patient was successfully treated with the autophagy inhibitor chloroquine after failure of the BRAFV600E inhibitor vemurafenib, suggesting autophagy inhibition overcame the kinase inhibitor resistance. We tested this hypothesis in vemurafenib-resistant brain tumors. Genetic and pharmacological autophagy inhibition overcame molecularly distinct resistance mechanisms, inhibited tumor cell growth, and increased cell death. Patients with resistance had favorable clinical responses when chloroquine was added to vemurafenib. This provides a fundamentally different strategy to circumvent multiple mechanisms of kinase inhibitor resistance that could be rapidly tested in clinical trials in patients with BRAFV600E brain tumors. DOI: http://dx.doi.org/10.7554/eLife.19671.001 PMID:28094001

  6. Inhibiting the HSP90 chaperone destabilizes macrophage migration inhibitory factor and thereby inhibits breast tumor progression

    PubMed Central

    Schulz, Ramona; Marchenko, Natalia D.; Holembowski, Lena; Fingerle-Rowson, Günter; Pesic, Marina; Zender, Lars; Dobbelstein, Matthias

    2012-01-01

    Intracellular macrophage migration inhibitory factor (MIF) often becomes stabilized in human cancer cells. MIF can promote tumor cell survival, and elevated MIF protein correlates with tumor aggressiveness and poor prognosis. However, the molecular mechanism facilitating MIF stabilization in tumors is not understood. We show that the tumor-activated HSP90 chaperone complex protects MIF from degradation. Pharmacological inhibition of HSP90 activity, or siRNA-mediated knockdown of HSP90 or HDAC6, destabilizes MIF in a variety of human cancer cells. The HSP90-associated E3 ubiquitin ligase CHIP mediates the ensuing proteasome-dependent MIF degradation. Cancer cells contain constitutive endogenous MIF–HSP90 complexes. siRNA-mediated MIF knockdown inhibits proliferation and triggers apoptosis of cultured human cancer cells, whereas HSP90 inhibitor-induced apoptosis is overridden by ectopic MIF expression. In the ErbB2 transgenic model of human HER2-positive breast cancer, genetic ablation of MIF delays tumor progression and prolongs overall survival of mice. Systemic treatment with the HSP90 inhibitor 17AAG reduces MIF expression and blocks growth of MIF-expressing, but not MIF-deficient, tumors. Together, these findings identify MIF as a novel HSP90 client and suggest that HSP90 inhibitors inhibit ErbB2-driven breast tumor growth at least in part by destabilizing MIF. PMID:22271573

  7. ET-04MEBENDAZOLE IS EFFICACIOUS IN DIVERSE MEDULLOBLASTOMA TUMOR MODELS AND INHIBITS TUMOR ANGIOGENESIS

    PubMed Central

    Bai, Renyuan; Staedtke, Verena; Rudin, Charles; Bunz, Fred; Riggins, Gregory

    2014-01-01

    Medulloblastoma is the leading cause of cancer death in children. Surgery, radiotherapy and chemotherapy regimens are the current standard for treatment. While effective in most patients, those have long-term neurological sequelae in survivors, and a significant fraction of patients still succumb to the disease. In this study, we found that mebendazole (MBZ), an FDA-approved antiparasitic, demonstrated significant anti-tumor efficacy in etiologically distinct medulloblastoma mouse models. MBZ significantly improved the survival of mice with orthotopic xenograft tumors derived from the SHH group and group 3 medulloblastomas and was also highly efficacious against a PTCH1-mutant medulloblastoma with acquired resistance to the SMO inhibitor vismodgib. Analysis of the vasculature in rodent tumors revealed that MBZ selectively inhibited tumor angiogenesis but not the normal brain vasculature, and inhibited the kinase activity of VEGFR2 in vitro and in vivo. This study demonstrates that MBZ could be a highly promising therapeutic for medulloblastoma with anti- angiogenesis activity.

  8. Sensitization by dietary docosahexaenoic acid of rat mammary carcinoma to anthracycline: a role for tumor vascularization.

    PubMed

    Colas, Séverine; Mahéo, Karine; Denis, Fabrice; Goupille, Caroline; Hoinard, Claude; Champeroux, Pascal; Tranquart, François; Bougnoux, Philippe

    2006-10-01

    To investigate whether dietary docosahexaenoic acid (DHA), a peroxidizable polyunsaturated omega-3 fatty acids, sensitizes rat mammary tumors to anthracyclines and whether its action interferes with tumor vascularization, a critical determinant of tumor growth. Female Sprague-Dawley rats were initiated by N-methylnitrosourea to develop mammary tumors and then assigned to a control group (n = 18), receiving a supplementation of palm oil, or to a DHA group (n = 54), supplemented with a microalgae-produced oil (DHASCO, 1.5 g/d). The DHA group was equally subdivided into three subgroups with addition of different amounts of alpha-tocopherol. Epirubicin was injected weekly during 6 weeks after the largest tumor reached 1.5 cm(2), and subsequent changes in the tumor surface were evaluated. Tumor vascularization was assessed by power Doppler sonography before and during chemotherapy. DHA and alpha-tocopherol were readily absorbed and incorporated into rat tissues. Epirubicin induced a 45% mammary tumor regression in the DHA-supplemented group, whereas no tumor regression was observed in the control group. In the DHA group, before chemotherapy was initiated, tumor vascular density was 43% lower than in the control group and remained lower during chemotherapy. Enhancement of epirubicin efficacy by DHA was abolished in a dose-dependent manner by alpha-tocopherol, and the same trend was observed for DHA-induced reduction in tumor vascular density. Dietary DHA supplementation led to a reduction in tumor vascularization before the enhancement of any response to anthracyclines, suggesting that DHA chemosensitizes mammary tumors through an inhibition of the host vascular response to the tumor.

  9. BPIC: A novel anti-tumor lead capable of inhibiting inflammation and scavenging free radicals.

    PubMed

    Li, Shan; Wang, Yuji; Zhao, Ming; Wu, Jianhui; Peng, Shiqi

    2015-03-01

    Inflammation has a critical role in the tumor progression, free radical damage can worse the status of patients in cancer condition. The anti-cancer agents capable of inhibiting inflammation and scavenging free radicals attract a lot of our interest. Aimed at the discovery of such anti-tumor agent, a novel intercalator, benzyl 1-[4-hydroxy-3-(methoxycarbonyl)-phenyl-9H-pyrido[3,4-b]indole-3-carboxylate (BPIC) was presented. The docking investigation of BPIC and doxorubicin towards the DNA (PDB ID: 1NAB) gave equal score and similar feature. The anti-proliferation assay of 8 cancer cells identified S180 cells had equal sensitivity to BPIC and doxorubicin. The anti-tumor assay defined the efficacy of BPIC been 2 folds higher than that of doxorubicin. At 1μmol/kg of dose BPIC effectively inhibited xylene-induced ear edema and decreased the plasma TNF-α and IL-8 of the mice. BPIC scavenged ∙OH, ∙O2(-) and NO free radicals in a concentration dependent manner and NO free radicals had the highest sensitivity. BPIC could be a novel anti-tumor lead capable of simultaneously inhibiting inflammation and scavenging free radicals.

  10. RSUME inhibits VHL and regulates its tumor suppressor function.

    PubMed

    Gerez, J; Tedesco, L; Bonfiglio, J J; Fuertes, M; Barontini, M; Silberstein, S; Wu, Y; Renner, U; Páez-Pereda, M; Holsboer, F; Stalla, G K; Arzt, E

    2015-09-10

    Somatic mutations or loss of von Hippel-Lindau (pVHL) happen in the majority of VHL disease tumors, which present a constitutively active Hypoxia Inducible Factor (HIF), essential for tumor growth. Recently described mechanisms for pVHL modulation shed light on the open question of the HIF/pVHL pathway regulation. The aim of the present study was to determine the molecular mechanism by which RSUME stabilizes HIFs, by studying RSUME effect on pVHL function and to determine the role of RSUME on pVHL-related tumor progression. We determined that RSUME sumoylates and physically interacts with pVHL and negatively regulates the assembly of the complex between pVHL, Elongins and Cullins (ECV), inhibiting HIF-1 and 2α ubiquitination and degradation. We found that RSUME is expressed in human VHL tumors (renal clear-cell carcinoma (RCC), pheochromocytoma and hemangioblastoma) and by overexpressing or silencing RSUME in a pVHL-HIF-oxygen-dependent degradation stability reporter assay, we determined that RSUME is necessary for the loss of function of type 2 pVHL mutants. The functional RSUME/pVHL interaction in VHL-related tumor progression was further confirmed using a xenograft assay in nude mice. RCC clones, in which RSUME was knocked down and express either pVHL wt or type 2 mutation, have an impaired tumor growth, as well as HIF-2α, vascular endothelial growth factor A and tumor vascularization diminution. This work shows a novel mechanism for VHL tumor progression and presents a new mechanism and factor for targeting tumor-related pathologies with pVHL/HIF altered function.

  11. ME-10TUMOR MICROENVIRONMENT INFILTRATING MYELOID DERIVED SUPPRESSOR CELLS INHIBIT ANTI-TUMOR T CELL RESPONSES

    PubMed Central

    Kamran, Neha; Ayala, Mariela; Li, Youping; Assi, Hikmat; Candolfi, Marianela; Dzaman, Marta; Lowenstein, Pedro; Castro, Maria

    2014-01-01

    MDSCs represent a population of immature myeloid cells at various stages of differentiation that inhibit anti-tumor T cell-mediated responses. We demonstrate the accumulation of MDSCs in GL26 induced glioma and B16 melanoma bearing mice. Absolute numbers of Ly-6G+ (Gr-1high) MDSCs showed a 200 fold increase within the tumor microenvironment (TME) 28 days post-tumor implantation. The numbers of Ly-6C+ (Gr-1low) MDSCs also showed a similar trend within the TME. While this massive influx of MDSCs was noted within intracranial tumors, MDSC levels did not increase in the dLNs, spleen or bone marrow (BM) of intracranial tumor bearing mice. MDSCs numbers were significantly elevated in the blood of GL26 intracranial tumor bearing mice at 28 days. Mice bearing B16 tumors in the flank showed a ∼5 fold increased influx of Ly-6G+ MDSCs while the Ly6C+ MDSCs increased marginally by 1.1 fold within the tumor mass. Levels of circulating MDSCs also increased by ∼10 fold, while the levels of splenic MDSCs did not change. While both Ly-6G+ and Ly6C+ MDSCs isolated from the brain TME of GL26 intracranial tumor bearing mice inhibited antigen-specific T cell proliferation, Ly6C+ MDSC were found to be more efficient. Ly6G+ or Ly6C+ MDSCs from the bone marrow of intracranial tumor bearing mice failed to suppress antigen-specific T cell proliferation. Splenic and bone marrow MDSCs from naïve mice also did not inhibit antigen-specific T cell proliferation suggesting that TME derived factors may activate MDSCs to exert their immune-suppressive properties. Microarray analysis of glioma cell lines showed elevated levels of CXCL1 mRNA and splenic MDSCs from GL26 tumor mice showed upregulation of the CXCR2 mRNA. Preliminary experiments indicate that CXCR2 signaling mediates MDSC chemotaxis. Overall, our data suggests that strategies that inhibit MDSC recruitment to the TME and/or block their activity could enhance the T cell mediated tumor clearance.

  12. Interleukin-2 inhibits proliferation of HPV-associated tumor cells and halts tumor growth in vivo.

    PubMed

    Casana, Patricia H; Hernandez, Hector; Arana, Manuel J

    2002-12-20

    Previous studies have shown inhibition of cervical cancer cell growth by treatment with high concentrations of IL-2. In the present study, we evaluated the in vitro and in vivo effects of recombinant human IL-2 on HPV-associated tumor cells (3T3-16). Treatment of 3T3-16 cells with rhIL-2 for 72 h inhibited cell growth in a dose-dependent manner and this effect was evidenced at nanomolar concentrations. These tumor cells expressed mRNA for beta and gamma subunits of the IL-2 receptor, which are required for signal transduction. In experiments to explore the effect of IL-2 on the growth of the HPV-associated tumor, mice received rhIL-2 through different routes: (i) intraperitoneal; (ii) subcutaneous, at the tumor inoculation site; or (iii) subcutaneous, distant from the tumor inoculation site. An effective antitumor response was observed only in those animals that received IL-2 at the tumor site (P<0.01). These results indicate the potential adequacy of therapeutic strategies based on local administration of rhIL-2 for cervical carcinoma, not only based on the ability of this cytokine to stimulate cellular-mediated immunity but also because of its direct effects on tumor cells.

  13. Inhibition of autophagy stimulate molecular iodine-induced apoptosis in hormone independent breast tumors

    SciTech Connect

    Singh, Preeti; Godbole, Madan; Rao, Geeta; Annarao, Sanjay; Mitra, Kalyan; Roy, Raja; Ingle, Arvind; Agarwal, Gaurav; Tiwari, Swasti

    2011-11-11

    Highlights: Black-Right-Pointing-Pointer Molecular iodine (I{sub 2}) causes non-apoptotic cell death in MDA-MB231 breast tumor cells. Black-Right-Pointing-Pointer Autophagy is activated as a survival mechanism in response to I{sub 2} in MDA-MB231. Black-Right-Pointing-Pointer Autophagy inhibition sensitizes tumor cells to I{sub 2}-induced apoptotic cell death. Black-Right-Pointing-Pointer Autophagy inhibitor potentiates apoptosis and tumor regressive effects of I{sub 2} in mice. -- Abstract: Estrogen receptor negative (ER{sup -ve}) and p53 mutant breast tumors are highly aggressive and have fewer treatment options. Previously, we showed that molecular Iodine (I{sub 2}) induces apoptosis in hormone responsive MCF-7 breast cancer cells, and non-apoptotic cell death in ER{sup -ve}-p53 mutant MDA-MB231 cells (Shrivastava, 2006). Here we show that I{sub 2} (3 {mu}M) treatment enhanced the features of autophagy in MDA-MB231 cells. Since autophagy is a cell survival response to most anti-cancer therapies, we used both in vitro and in vivo systems to determine whether ER{sup -ve} mammary tumors could be sensitized to I{sub 2}-induced apoptosis by inhibiting autophagy. Autophagy inhibition with chloroquine (CQ) and inhibitors for PI3K (3MA, LY294002) and H+/ATPase (baflomycin) resulted in enhanced cell death in I{sub 2} treated MDA-MB231 cells. Further, CQ (20 {mu}M) in combination with I{sub 2}, showed apoptotic features such as increased sub-G1 fraction ({approx}5-fold), expression of cleaved caspase-9 and -3 compared to I{sub 2} treatment alone. Flowcytometry of I{sub 2} and CQ co-treated cells revealed increase in mitochondrial membrane permeability (p < 0.01) and translocation of cathepsin D activity to cytosol relative to I{sub 2} treatment. For in vivo studies ICRC mice were transplanted subcutaneously with MMTV-induced mammary tumors. A significant reduction in tumor volumes, as measured by MRI, was found in I{sub 2} and CQ co-treated mice relative to I{sub 2} or

  14. PD-L1 on tumor cells is sufficient for immune evasion in immunogenic tumors and inhibits CD8 T cell cytotoxicity.

    PubMed

    Juneja, Vikram R; McGuire, Kathleen A; Manguso, Robert T; LaFleur, Martin W; Collins, Natalie; Haining, W Nicholas; Freeman, Gordon J; Sharpe, Arlene H

    2017-04-03

    It is unclear whether PD-L1 on tumor cells is sufficient for tumor immune evasion or simply correlates with an inflamed tumor microenvironment. We used three mouse tumor models sensitive to PD-1 blockade to evaluate the significance of PD-L1 on tumor versus nontumor cells. PD-L1 on nontumor cells is critical for inhibiting antitumor immunity in B16 melanoma and a genetically engineered melanoma. In contrast, PD-L1 on MC38 colorectal adenocarcinoma cells is sufficient to suppress antitumor immunity, as deletion of PD-L1 on highly immunogenic MC38 tumor cells allows effective antitumor immunity. MC38-derived PD-L1 potently inhibited CD8(+) T cell cytotoxicity. Wild-type MC38 cells outcompeted PD-L1-deleted MC38 cells in vivo, demonstrating tumor PD-L1 confers a selective advantage. Thus, both tumor- and host-derived PD-L1 can play critical roles in immunosuppression. Differences in tumor immunogenicity appear to underlie their relative importance. Our findings establish reduced cytotoxicity as a key mechanism by which tumor PD-L1 suppresses antitumor immunity and demonstrate that tumor PD-L1 is not just a marker of suppressed antitumor immunity. © 2017 Juneja et al.

  15. Colon tumor cell growth inhibitory activity of sulindac sulfide and other NSAIDs is associated with PDE5 inhibition

    PubMed Central

    Tinsley, Heather N.; Gary, Bernard D.; Thaiparambil, Jose; Li, Nan; Lu, Wenyan; Li, Yonghe; Maxuitenko, Yulia Y.; Keeton, Adam B.; Piazza, Gary A.

    2010-01-01

    In experimental studies, nonsteroidal anti-inflammatory drugs (NSAIDs) display promising antineoplastic activity, but toxicity resulting from cyclooxygenase (COX) inhibition limits their clinical use for chemoprevention. Studies suggest that the mechanism may be COX independent, although alternative targets have not been well defined. Here we show that the NSAID, sulindac sulfide (SS) inhibits cGMP phosphodiesterase (PDE) activity in colon tumor cell lysates at concentrations that inhibit colon tumor cell growth in vitro and in vivo. A series of chemically diverse NSAIDs inhibited cGMP hydrolysis at concentrations that correlate with their potency to inhibit colon tumor cell growth, while no correlation was observed with COX-2 inhibition. Consistent with its selectivity for inhibiting cGMP hydrolysis compared with cAMP hydrolysis, SS inhibited the cGMP specific PDE5 isozyme and increased cGMP levels in colon tumor cells. Of numerous PDE isozyme specific inhibitors evaluated, only the PDE5 selective inhibitor MY5445 inhibited colon tumor cell growth. The effects of SS and MY5445 on cell growth were associated with inhibition of β-catenin mediated transcriptional activity to suppress the synthesis of cyclin D and survivin, which regulate tumor cell proliferation and apoptosis, respectively. SS had minimal effects on cGMP PDE activity in normal colonocytes, which displayed reduced sensitivity to SS and did not express PDE5. PDE5 was found to be overexpressed in colon tumor cell lines as well as in colon adenomas and adenocarcinomas compared to normal colonic mucosa. These results suggest that PDE5 inhibition, cGMP elevation, and inhibition of β-catenin transcriptional activity may contribute to the chemopreventive properties of certain NSAIDs. PMID:20876730

  16. Kalkitoxin Inhibits Angiogenesis, Disrupts Cellular Hypoxic Signaling, and Blocks Mitochondrial Electron Transport in Tumor Cells

    PubMed Central

    Morgan, J. Brian; Liu, Yang; Coothankandaswamy, Veena; Mahdi, Fakhri; Jekabsons, Mika B.; Gerwick, William H.; Valeriote, Frederick A.; Zhou, Yu-Dong; Nagle, Dale G.

    2015-01-01

    The biologically active lipopeptide kalkitoxin was previously isolated from the marine cyanobacterium Moorea producens (Lyngbya majuscula). Kalkitoxin exhibited N-methyl-d-aspartate (NMDA)-mediated neurotoxicity and acted as an inhibitory ligand for voltage-sensitive sodium channels in cultured rat cerebellar granule neurons. Subsequent studies revealed that kalkitoxin generated a delayed form of colon tumor cell cytotoxicity in 7-day clonogenic cell survival assays. Cell line- and exposure time-dependent cytostatic/cytotoxic effects were previously observed with mitochondria-targeted inhibitors of hypoxia-inducible factor-1 (HIF-1). The transcription factor HIF-1 functions as a key regulator of oxygen homeostasis. Therefore, we investigated the ability of kalkitoxin to inhibit hypoxic signaling in human tumor cell lines. Kalkitoxin potently and selectively inhibited hypoxia-induced activation of HIF-1 in T47D breast tumor cells (IC50 5.6 nM). Mechanistic studies revealed that kalkitoxin inhibits HIF-1 activation by suppressing mitochondrial oxygen consumption at electron transport chain (ETC) complex I (NADH-ubiquinone oxidoreductase). Further studies indicate that kalkitoxin targets tumor angiogenesis by blocking the induction of angiogenic factors (i.e., VEGF) in tumor cells. PMID:25803180

  17. Growth inhibition, tumor maturation, and extended survival in experimental brain tumors in rats treated with phenylacetate.

    PubMed

    Ram, Z; Samid, D; Walbridge, S; Oshiro, E M; Viola, J J; Tao-Cheng, J H; Shack, S; Thibault, A; Myers, C E; Oldfield, E H

    1994-06-01

    Phenylacetate is a naturally occurring plasma component that suppresses the growth of tumor cells and induces differentiation in vitro. To evaluate the in vivo potential and preventive and therapeutic antitumor efficacy of sodium phenylacetate against malignant brain tumors, Fischer 344 rats (n = 50) bearing cerebral 9L gliosarcomas received phenylacetate by continuous s.c. release starting on the day of tumor inoculation (n = 10) using s.c. osmotic minipumps (550 mg/kg/day for 28 days). Rats with established brain tumors (n = 12) received continuous s.c. phenylacetate supplemented with additional daily i.p. dose (300 mg/kg). Control rats (n = 25) were treated in a similar way with saline. Rats were sacrificed during treatment for electron microscopic studies of their tumors, in vivo proliferation assays, and measurement of phenylacetate levels in the serum and cerebrospinal fluid. Treatment with phenylacetate extended survival when started on the day of tumor inoculation (P < 0.01) or 7 days after inoculation (P < 0.03) without any associated adverse effects. In the latter group, phenylacetate levels in pooled serum and cerebrospinal fluid samples after 7 days of treatment were in the therapeutic range as determined in vitro (2.45 mM in serum and 3.1 mM in cerebrospinal fluid). Electron microscopy of treated tumors demonstrated marked hypertrophy and organization of the rough endoplasmic reticulum, indicating cell differentiation, in contrast to the scant and randomly distributed endoplasmic reticulum in tumors from untreated animals. In addition, in vitro studies demonstrated dose-dependent inhibition of the rate of tumor proliferation and restoration of anchorage dependency, a marker of phenotypic reversion. Phenylacetate, used at clinically achievable concentrations, prolongs survival of rats with malignant brain tumors through induction of tumor differentiation. Its role in the treatment of brain tumors and other cancers should be explored further.

  18. Hematoporphyrin-derivative photodynamic in-vitro sensitivity testing for brain tumors

    NASA Astrophysics Data System (ADS)

    Plattner, Michael; Bernwick, Walter; Kostron, Herwig

    1993-03-01

    Brain tumors of various histologies were subjected to an in-vitro photodynamic-sensitivity test. The studies were performed on primary cultures of human glioblastomas, meningiomas, and ependymomas, which were exposed to increasing concentrations of hematoporphyrin derivative and 60 J/cm2 delivered by an argon-dye laser at 632 nm. A growth inhibition of 75% was demonstrated at a concentration of 25 (mu) g and 10 (mu) g HPD/ml medium for two different glioblastomas, respectively. A growth inhibition of 75% was observed in the ependymoma line at 10 and 50 (mu) g HPD/ml with and without light, respectively. The meningioma demonstrated a 75% inhibition already at (mu) g and 75 (mu) g/ml medium with and without light, respectively. These results demonstrate a significant difference in the response of brain tumors to photodynamic treatment (PDT). In vitro-PDT-assay should be taken into account if clinical application of PDT is considered.

  19. Combined epigenetic and differentiation-based treatment inhibits neuroblastoma tumor growth and links HIF2α to tumor suppression.

    PubMed

    Westerlund, Isabelle; Shi, Yao; Toskas, Konstantinos; Fell, Stuart M; Li, Shuijie; Surova, Olga; Södersten, Erik; Kogner, Per; Nyman, Ulrika; Schlisio, Susanne; Holmberg, Johan

    2017-07-25

    Neuroblastoma is a pediatric cancer characterized by variable outcomes ranging from spontaneous regression to life-threatening progression. High-risk neuroblastoma patients receive myeloablative chemotherapy with hematopoietic stem-cell transplant followed by adjuvant retinoid differentiation treatment. However, the overall survival remains low; hence, there is an urgent need for alternative therapeutic approaches. One feature of high-risk neuroblastoma is the high level of DNA methylation of putative tumor suppressors. Combining the reversibility of DNA methylation with the differentiation-promoting activity of retinoic acid (RA) could provide an alternative strategy to treat high-risk neuroblastoma. Here we show that treatment with the DNA-demethylating drug 5-Aza-deoxycytidine (AZA) restores high-risk neuroblastoma sensitivity to RA. Combined systemic distribution of AZA and RA impedes tumor growth and prolongs survival. Genome-wide analysis of treated tumors reveals that this combined treatment rapidly induces a HIF2α-associated hypoxia-like transcriptional response followed by an increase in neuronal gene expression and a decrease in cell-cycle gene expression. A small-molecule inhibitor of HIF2α activity diminishes the tumor response to AZA+RA treatment, indicating that the increase in HIF2α levels is a key component in tumor response to AZA+RA. The link between increased HIF2α levels and inhibited tumor growth is reflected in large neuroblastoma patient datasets. Therein, high levels of HIF2α, but not HIF1α, significantly correlate with expression of neuronal differentiation genes and better prognosis but negatively correlate with key features of high-risk tumors, such as MYCN amplification. Thus, contrary to previous studies, our findings indicate an unanticipated tumor-suppressive role for HIF2α in neuroblastoma.

  20. Salinomycin inhibits osteosarcoma by targeting its tumor stem cells.

    PubMed

    Tang, Qing-Lian; Zhao, Zhi-Qiang; Li, Jin-Chun; Liang, Yi; Yin, Jun-Qiang; Zou, Chang-Ye; Xie, Xian-Biao; Zeng, Yi-Xin; Shen, Jing-Nan; Kang, Tiebang; Wang, Jin

    2011-12-01

    Osteosarcoma is the most common primary bone tumor in children and adolescents and is typically associated with a poor prognosis. Tumor stem cells (TSCs) are presumed to drive tumor initiation and tumor relapse or metastasis. Hence, the poor prognosis of osteosarcoma likely results from a failure to target the osteosarcoma stem cells. Here, we have utilized three different methods to enrich TSCs in osteosarcoma and further evaluated whether salinomycin could selectively target TSCs in osteosarcoma. Our results indicated that sarcosphere selection, chemotherapy selection and stem cell marker OCT4 or SOX2 over-expression are all effective in the enrichment of TSCs from osteosarcoma cell lines. Further investigation found that salinomycin inhibited osteosarcoma by selectively targeting its stem cells both in vitro and in vivo without severe side effects, and the Wnt/β-catenin signaling pathway may be involved in this inhibition of salinomycin. Taken together, we have identified that salinomycin is an effective inhibitor of osteosarcoma stem cells, supporting the use of salinomycin for elimination of osteosarcoma stem cells and implying a need for further clinical evaluation.

  1. Silencing of ATF2 inhibits growth of pancreatic cancer cells and enhances sensitivity to chemotherapy.

    PubMed

    Li, Mu; Wu, Xingda; Liu, Ning; Li, Xiaoying; Meng, Fanbin; Song, Shaowei

    2017-03-20

    Pancreatic cancer is one of the leading causes of cancer-related death worldwide. Activating transcription factor 2 (ATF2) is a multifunctional transcription factor, and is implicated in tumor progress, yet its role in pancreatic cancer remains unclear. In the present study, the level of ATF2 in pancreatic cancer tissues and the adjacent non-tumorous tissues was detected by quantitative real-time PCR and western blot. The roles of ATF2 in the proliferation, cell cycle, and apoptosis of pancreatic cancer cells were investigated through ATF2 silencing, and the effect of ATF2 shRNA on the sensitivity of pancreatic cancer cells to gemcitabine, an anti-tumor drug, was explored. The results of our study showed that the ATF2 level in the pancreatic cancer tissues was higher than that in the adjacent non-tumorous tissues. Silencing of ATF2 was found to inhibit proliferation, arrest cell cycle at G1 phase and induce apoptosis in pancreatic cancer cells. Moreover, ATF2 silencing enhanced gemcitabine-induced growth-inhibition and apoptosis-induction effects in pancreatic cancer cells. In summary, silencing of ATF2 inhibited the growth of pancreatic cancer cells and enhanced the anti-tumor effects of gemcitabine, suggesting that ATF2 plays a pro-survival role in pancreatic cancer. Our results also propose that a high level of ATF2 may serve as a potential biomarker of pancreatic cancer, and that ATF2 may become a potential target for anti-tumor therapy.

  2. PEITC treatment suppresses myeloid derived tumor suppressor cells to inhibit breast tumor growth.

    PubMed

    Gupta, Parul; Wright, Stephen E; Srivastava, Sanjay K

    2015-02-01

    Breast tumors are heterogeneous with a complex etiology. The immune system plays a crucial role in the development of tumors and can facilitate tumor growth pleiotropically. Myeloid derived suppressor cells (MDSCs) generate reactive oxygen species (ROS) and cytokines to suppress T cells, dendritic cells and natural killer (NK) cells. Hence, the inhibition of MDSCs could be an important strategy for anticancer therapeutics. Phenethyl isothiocyanate (PEITC), a bioactive compound present in cruciferous vegetables, is known to have anticancer properties. However, the effects of PEITC administration on the immune system have not been previously reported. In the current study, we evaluated the effects of administering PEITC to immunocompromised NOD-SCID IL2Rγ(-/-) (SCID/NSG) host mice bearing MDA-MB-231 xenografts on MDSCs in the peripheral blood. Our results reveal that oral administration of 12 μmol PEITC attenuated tumor growth by 76%. This was marked tumor-inhibitory phenotype was associated with a significant reduction in the levels of MDSCs bearing the surface markers CD33, CD34 and CD11b in PEITC treated mice, indicating that overall tumor growth suppression by PEITC correlates with inhibition of MDSCs. To the best of our knowledge, this is the first study showing effects of PEITC on MDSCs.

  3. MerTK inhibition in tumor leukocytes decreases tumor growth and metastasis

    PubMed Central

    Cook, Rebecca S.; Jacobsen, Kristen M.; Wofford, Anne M.; DeRyckere, Deborah; Stanford, Jamie; Prieto, Anne L.; Redente, Elizabeth; Sandahl, Melissa; Hunter, Debra M.; Strunk, Karen E.; Graham, Douglas K.; Earp, H. Shelton

    2013-01-01

    MerTK, a receptor tyrosine kinase (RTK) of the TYRO3/AXL/MerTK family, is expressed in myeloid lineage cells in which it acts to suppress proinflammatory cytokines following ingestion of apoptotic material. Using syngeneic mouse models of breast cancer, melanoma, and colon cancer, we found that tumors grew slowly and were poorly metastatic in MerTK–/– mice. Transplantation of MerTK–/– bone marrow, but not wild-type bone marrow, into lethally irradiated MMTV-PyVmT mice (a model of metastatic breast cancer) decreased tumor growth and altered cytokine production by tumor CD11b+ cells. Although MerTK expression was not required for tumor infiltration by leukocytes, MerTK–/– leukocytes exhibited lower tumor cell–induced expression of wound healing cytokines, e.g., IL-10 and growth arrest-specific 6 (GAS6), and enhanced expression of acute inflammatory cytokines, e.g., IL-12 and IL-6. Intratumoral CD8+ T lymphocyte numbers were higher and lymphocyte proliferation was increased in tumor-bearing MerTK–/– mice compared with tumor-bearing wild-type mice. Antibody-mediated CD8+ T lymphocyte depletion restored tumor growth in MerTK–/– mice. These data demonstrate that MerTK signaling in tumor-associated CD11b+ leukocytes promotes tumor growth by dampening acute inflammatory cytokines while inducing wound healing cytokines. These results suggest that inhibition of MerTK in the tumor microenvironment may have clinical benefit, stimulating antitumor immune responses or enhancing immunotherapeutic strategies. PMID:23867499

  4. MerTK inhibition in tumor leukocytes decreases tumor growth and metastasis.

    PubMed

    Cook, Rebecca S; Jacobsen, Kristen M; Wofford, Anne M; DeRyckere, Deborah; Stanford, Jamie; Prieto, Anne L; Redente, Elizabeth; Sandahl, Melissa; Hunter, Debra M; Strunk, Karen E; Graham, Douglas K; Earp, H Shelton

    2013-08-01

    MerTK, a receptor tyrosine kinase (RTK) of the TYRO3/AXL/MerTK family, is expressed in myeloid lineage cells in which it acts to suppress proinflammatory cytokines following ingestion of apoptotic material. Using syngeneic mouse models of breast cancer, melanoma, and colon cancer, we found that tumors grew slowly and were poorly metastatic in MerTK-/- mice. Transplantation of MerTK-/- bone marrow, but not wild-type bone marrow, into lethally irradiated MMTV-PyVmT mice (a model of metastatic breast cancer) decreased tumor growth and altered cytokine production by tumor CD11b+ cells. Although MerTK expression was not required for tumor infiltration by leukocytes, MerTK-/- leukocytes exhibited lower tumor cell-induced expression of wound healing cytokines, e.g., IL-10 and growth arrest-specific 6 (GAS6), and enhanced expression of acute inflammatory cytokines, e.g., IL-12 and IL-6. Intratumoral CD8+ T lymphocyte numbers were higher and lymphocyte proliferation was increased in tumor-bearing MerTK-/- mice compared with tumor-bearing wild-type mice. Antibody-mediated CD8+ T lymphocyte depletion restored tumor growth in MerTK-/- mice. These data demonstrate that MerTK signaling in tumor-associated CD11b+ leukocytes promotes tumor growth by dampening acute inflammatory cytokines while inducing wound healing cytokines. These results suggest that inhibition of MerTK in the tumor microenvironment may have clinical benefit, stimulating antitumor immune responses or enhancing immunotherapeutic strategies.

  5. Bursts of Bipolar Microsecond Pulses Inhibit Tumor Growth

    NASA Astrophysics Data System (ADS)

    Sano, Michael B.; Arena, Christopher B.; Bittleman, Katelyn R.; Dewitt, Matthew R.; Cho, Hyung J.; Szot, Christopher S.; Saur, Dieter; Cissell, James M.; Robertson, John; Lee, Yong W.; Davalos, Rafael V.

    2015-10-01

    Irreversible electroporation (IRE) is an emerging focal therapy which is demonstrating utility in the treatment of unresectable tumors where thermal ablation techniques are contraindicated. IRE uses ultra-short duration, high-intensity monopolar pulsed electric fields to permanently disrupt cell membranes within a well-defined volume. Though preliminary clinical results for IRE are promising, implementing IRE can be challenging due to the heterogeneous nature of tumor tissue and the unintended induction of muscle contractions. High-frequency IRE (H-FIRE), a new treatment modality which replaces the monopolar IRE pulses with a burst of bipolar pulses, has the potential to resolve these clinical challenges. We explored the pulse-duration space between 250 ns and 100 μs and determined the lethal electric field intensity for specific H-FIRE protocols using a 3D tumor mimic. Murine tumors were exposed to 120 bursts, each energized for 100 μs, containing individual pulses 1, 2, or 5 μs in duration. Tumor growth was significantly inhibited and all protocols were able to achieve complete regressions. The H-FIRE protocol substantially reduces muscle contractions and the therapy can be delivered without the need for a neuromuscular blockade. This work shows the potential for H-FIRE to be used as a focal therapy and merits its investigation in larger pre-clinical models.

  6. Bursts of Bipolar Microsecond Pulses Inhibit Tumor Growth.

    PubMed

    Sano, Michael B; Arena, Christopher B; Bittleman, Katelyn R; DeWitt, Matthew R; Cho, Hyung J; Szot, Christopher S; Saur, Dieter; Cissell, James M; Robertson, John; Lee, Yong W; Davalos, Rafael V

    2015-10-13

    Irreversible electroporation (IRE) is an emerging focal therapy which is demonstrating utility in the treatment of unresectable tumors where thermal ablation techniques are contraindicated. IRE uses ultra-short duration, high-intensity monopolar pulsed electric fields to permanently disrupt cell membranes within a well-defined volume. Though preliminary clinical results for IRE are promising, implementing IRE can be challenging due to the heterogeneous nature of tumor tissue and the unintended induction of muscle contractions. High-frequency IRE (H-FIRE), a new treatment modality which replaces the monopolar IRE pulses with a burst of bipolar pulses, has the potential to resolve these clinical challenges. We explored the pulse-duration space between 250 ns and 100 μs and determined the lethal electric field intensity for specific H-FIRE protocols using a 3D tumor mimic. Murine tumors were exposed to 120 bursts, each energized for 100 μs, containing individual pulses 1, 2, or 5 μs in duration. Tumor growth was significantly inhibited and all protocols were able to achieve complete regressions. The H-FIRE protocol substantially reduces muscle contractions and the therapy can be delivered without the need for a neuromuscular blockade. This work shows the potential for H-FIRE to be used as a focal therapy and merits its investigation in larger pre-clinical models.

  7. Bursts of Bipolar Microsecond Pulses Inhibit Tumor Growth

    PubMed Central

    Sano, Michael B.; Arena, Christopher B.; Bittleman, Katelyn R.; DeWitt, Matthew R.; Cho, Hyung J.; Szot, Christopher S.; Saur, Dieter; Cissell, James M.; Robertson, John; Lee, Yong W.; Davalos, Rafael V.

    2015-01-01

    Irreversible electroporation (IRE) is an emerging focal therapy which is demonstrating utility in the treatment of unresectable tumors where thermal ablation techniques are contraindicated. IRE uses ultra-short duration, high-intensity monopolar pulsed electric fields to permanently disrupt cell membranes within a well-defined volume. Though preliminary clinical results for IRE are promising, implementing IRE can be challenging due to the heterogeneous nature of tumor tissue and the unintended induction of muscle contractions. High-frequency IRE (H-FIRE), a new treatment modality which replaces the monopolar IRE pulses with a burst of bipolar pulses, has the potential to resolve these clinical challenges. We explored the pulse-duration space between 250 ns and 100 μs and determined the lethal electric field intensity for specific H-FIRE protocols using a 3D tumor mimic. Murine tumors were exposed to 120 bursts, each energized for 100 μs, containing individual pulses 1, 2, or 5 μs in duration. Tumor growth was significantly inhibited and all protocols were able to achieve complete regressions. The H-FIRE protocol substantially reduces muscle contractions and the therapy can be delivered without the need for a neuromuscular blockade. This work shows the potential for H-FIRE to be used as a focal therapy and merits its investigation in larger pre-clinical models. PMID:26459930

  8. 3-Bromopyruvate inhibits human gastric cancer tumor growth in nude mice via the inhibition of glycolysis.

    PubMed

    Xian, Shu-Lin; Cao, Wei; Zhang, Xiao-Dong; Lu, Yun-Fei

    2015-02-01

    Tumor cells primarily depend upon glycolysis in order to gain energy. Therefore, the inhibition of glycolysis may inhibit tumor growth. Our previous study demonstrated that 3-bromopyruvate (3-BrPA) inhibited gastric cancer cell proliferation in vitro. However, the ability of 3-BrPA to suppress tumor growth in vivo, and its underlying mechanism, have yet to be elucidated. The aim of the present study was to investigate the inhibitory effect of 3-BrPA in an animal model of gastric cancer. It was identified that 3-BrPA exhibited strong inhibitory effects upon xenograft tumor growth in nude mice. In addition, the antitumor function of 3-BrPA exhibited a dose-effect association, which was similar to that of the chemotherapeutic agent, 5-fluorouracil. Furthermore, 3-BrPA exhibited low toxicity in the blood, liver and kidneys of the nude mice. The present study hypothesized that the inhibitory effect of 3-BrPA is achieved through the inhibition of hexokinase activity, which leads to the downregulation of B-cell lymphoma 2 (Bcl-2) expression, the upregulation of Bcl-2-associated X protein expression and the subsequent activation of caspase-3. These data suggest that 3-BrPA may be a novel therapy for the treatment of gastric cancer.

  9. CHIP is a novel tumor suppressor in pancreatic cancer and inhibits tumor growth through targeting EGFR

    PubMed Central

    Wang, Tianxiao; Yang, Jingxuan; Xu, Jianwei; Li, Jian; Cao, Zhe; Zhou, Li; You, Lei; Shu, Hong; Lu, Zhaohui; Li, Huihua; Li, Min; Zhang, Taiping; Zhao, Yupei

    2014-01-01

    Carboxyl terminus of heat shock protein 70-interacting protein (CHIP) is an E3 ubiquitin ligase that is involved in protein quality control and mediates several tumor-related proteins in many cancers, but the function of CHIP in pancreatic cancer is not known. Here we show that CHIP interacts and ubiquitinates epidermal growth factor receptor (EGFR) for proteasome-mediated degradation in pancreatic cancer cells, thereby inhibiting the activation of EGFR downstream pathways. CHIP suppressed cell proliferation, anchor-independent growth, invasion and migration, as well as enhanced apoptosis induced by erlotinib in vitro and in vivo. The expression of CHIP was decreased in pancreatic cancer tissues or sera. Low CHIP expression in tumor tissues was correlated with tumor differentiation and shorter overall survival. These observations indicate that CHIP serves as a novel tumor suppressor by down-regulating EGFR pathway in pancreatic cancer cells, decreased expression of CHIP was associated with poor prognosis in pancreatic cancer. PMID:24722501

  10. Depleting tumor-NQO1 Potentiates Anoikis and Inhibits Growth of NSCLC

    PubMed Central

    Chakrabarti, Gaurab; Boothman, David A.; Bey, Erik A.

    2015-01-01

    The fundamental role that NAD(P)H/quinone oxidoreductase 1 (NQO1) plays, in normal cells, as a cyto-protective enzyme guarding against stress induced by reactive oxygen species (ROS) is well documented. However, what is not known is whether the observed overexpression of NQO1 in neoplastic cells contributes to their survival. The current study discovered that depleting NQO1 expression in A549 and H292 lung adenocarcinoma cells caused an increase in ROS formation, inhibited anchorage-independent growth, increased anoikis sensitization and decreased 3-D tumor-spheroid invasion. These in vivo data further implicate tumor-NQO1 expression in a pro-tumor survival role, since its depletion suppressed cell proliferation and decreased lung tumor xenograft growth. Finally, these data reveal an exploitable link between tumor-NQO1 expression and the survival of lung tumors since NQO1 depletion significantly decreased the percentage of ALDH(high) cancer cells within the tumor population. PMID:26553038

  11. Tumor suppressor ING4 inhibits estrogen receptor activity in breast cancer cells

    PubMed Central

    Keenen, Madeline M; Kim, Suwon

    2016-01-01

    Resistance to antiestrogen therapy remains a significant problem in breast cancer. Low expression of inhibitor of growth 4 (ING4) in primary tumors has been correlated with increased rates of recurrence in estrogen receptor-positive (ER+) breast cancer patients, suggesting a role for ING4 in ER signaling. This study provides evidence that ING4 inhibits ER activity. ING4 overexpression increased the sensitivity of T47D and MCF7 ER+ breast cancer cells to hormone deprivation. ING4 attenuated maximal estrogen-dependent cell growth without affecting the dose–response of estrogen. These results indicated that ING4 functions as a noncompetitive inhibitor of estrogen signaling and may inhibit estrogen-independent ER activity. Supportive of this, treatment with fulvestrant but not tamoxifen rendered T47D cells sensitive to hormone deprivation as did ING4 overexpression. ING4 did not affect nuclear ERα protein expression, but repressed selective ER-target gene transcription. Taken together, these results demonstrated that ING4 inhibited estrogen-independent ER activity, suggesting that ING4-low breast tumors recur faster due to estrogen-independent ER activity that renders tamoxifen less effective. This study puts forth fulvestrant as a proposed therapy choice for patients with ING4-low ER+ breast tumors. PMID:27895513

  12. Retinal-conjugated pH-sensitive micelles induce tumor senescence for boosting breast cancer chemotherapy.

    PubMed

    Zhang, Yijuan; Li, Ping; Pan, Hong; Liu, Lanlan; Ji, Manyi; Sheng, Nan; Wang, Ce; Cai, Lintao; Ma, Yifan

    2016-03-01

    Evoking tumor cellular senescence, an irreversible status of cell growth quiescence, has been recently proposed as a potential strategy to improve the efficacy of cancer treatment. In the current study, all-trans retinal, the precursor of all-trans retinoic acid, was conjugated to dextran via hydrazone bond to generate amphiphilic dextran-retinal (DR) conjugates, which self-assembled into pH-sensitive DR micelles. Our results showed that DR micelles moderately inhibited MCF-7 breast cancer cell growth through inducing p21-associated cellular senescence, which relied on retinoic acid receptors (RARs) and was accompanied by significant G0/G1 cell cycle arrest. Moreover, DR micelles were capable of encapsulating doxorubicin (DOX) to generate DOX-loaded DD micelles, facilitating the uptake and release of DOX in cancer cells. Compared with free DOX, DD micelles more effectively suppressed tumor growth and prolonged survival time of mouse xenograft model through inducing tumor apoptosis and cellular senescence. However, blocking cellular senescence diminished DD-caused apoptosis in MCF-7 cells by 40-50%. Therefore, pH-sensitive DR micelles not only served as a potent platform for DOX delivery, but also enhanced the anti-tumor effect of DOX by inducing tumor cellular senescence. These data reveal a great potential of evoking tumor senescence with retinal-conjugated micelles for boosting breast cancer chemotherapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. AIF inhibits tumor metastasis by protecting PTEN from oxidation

    PubMed Central

    Shen, Shao-Ming; Guo, Meng; Xiong, Zhong; Yu, Yun; Zhao, Xu-Yun; Zhang, Fei-Fei; Chen, Guo-Qiang

    2015-01-01

    Apoptosis-inducing factor (AIF) exerts dual roles on cell death and survival, but its substrates as a putative oxidoreductase and roles in tumorigenesis remain elusive. Here, we report that AIF physically interacts with and inhibits the oxidation of phosphatase and tensin homolog on chromosome ten (PTEN), a tumor suppressor susceptible for oxidation-mediated inactivation. More intriguingly, we also identify PTEN as a mitochondrial protein and the ectopic expression of mitochondrial targeting sequence-carrying PTEN almost completely inhibits Akt phosphorylation in PTEN-deficient cells. AIF knockdown causes oxidation-mediated inactivation of the lipid phosphatase activity of PTEN, with ensuing activation of Akt kinase, phosphorylation of the Akt substrate GSK-3β, and activation of β-catenin signaling in cancer cells. Through its effect on β-catenin signaling, AIF inhibits epithelial–mesenchymal transition (EMT) and metastasis of cancer cells in vitro and in orthotopically implanted xenografts. Accordingly, the expression of AIF is correlated with the survival of human patients with cancers of multiple origins. These results identify PTEN as the substrate of AIF oxidoreductase and reveal a novel function for AIF in controlling tumor metastasis. PMID:26415504

  14. Inhibition of tumor growth and metastasis by photoimmunotherapy targeting tumor-associated macrophage in a sorafenib-resistant tumor model.

    PubMed

    Zhang, Chenran; Gao, Liquan; Cai, Yuehong; Liu, Hao; Gao, Duo; Lai, Jianhao; Jia, Bing; Wang, Fan; Liu, Zhaofei

    2016-04-01

    Tumor-associated macrophages (TAMs) play essential roles in tumor invasion and metastasis, and contribute to drug resistance. Clinical evidence suggests that TAM levels are correlated with local tumor relapse, distant metastasis, and poor prognosis in patients. In this study, we synthesized a TAM-targeted probe (IRD-αCD206) by conjugating a monoclonal anti-CD206 antibody with a near-infrared phthalocyanine dye. We then investigated the potential application of the IRD-αCD206 probe to near-infrared fluorescence (NIRF) imaging and photoimmunotherapy (PIT) of tumors resistant to treatment with the kinase inhibitor sorafenib. Sorafenib treatment had no effect on tumor growth in a 4T1 mouse model of breast cancer, but induced M2 macrophage polarization in tumors. M2 macrophage recruitment by sorafenib-treated 4T1 tumors was noninvasively visualized by in vivo NIRF imaging of IRD-αCD206. Small-animal single-photon emission computed tomography (SPECT)/CT and intratumoral microdistribution analysis indicated TAM-specific localization of the IRD-αCD206 probe in 4T1 tumors after several rounds of sorafenib treatment. Upon light irradiation, IRD-αCD206 suppressed the growth of sorafenib-resistant tumors. In vivo CT imaging and ex vivo histological analysis confirmed the inhibition of lung metastasis in mice by IRD-αCD206 PIT. These results demonstrate the utility of the IRD-αCD206 probe for TAM-targeted diagnostic imaging and treatment of tumors that are resistant to conventional therapeutics.

  15. Inhibition Effect of a Custom Peptide on Lung Tumors

    PubMed Central

    Huang, Chih-Yu; Huang, Hsuan-Yu; Forrest, Michael D.; Pan, Yun-Ru; Wu, Wei-Jen; Chen, Hueih-Min

    2014-01-01

    Cecropin B is a natural antimicrobial peptide and CB1a is a custom, engineered modification of it. In vitro, CB1a can kill lung cancer cells at concentrations that do not kill normal lung cells. Furthermore, in vitro, CB1a can disrupt cancer cells from adhering together to form tumor-like spheroids. Mice were xenografted with human lung cancer cells; CB1a could significantly inhibit the growth of tumors in this in vivo model. Docetaxel is a drug in present clinical use against lung cancers; it can have serious side effects because its toxicity is not sufficiently limited to cancer cells. In our studies in mice: CB1a is more toxic to cancer cells than docetaxel, but dramatically less toxic to healthy cells. PMID:25310698

  16. mTOR inhibitors block Kaposi sarcoma growth by inhibiting essential autocrine growth factors and tumor angiogenesis.

    PubMed

    Roy, Debasmita; Sin, Sang-Hoon; Lucas, Amy; Venkataramanan, Raman; Wang, Ling; Eason, Anthony; Chavakula, Veenadhari; Hilton, Isaac B; Tamburro, Kristen M; Damania, Blossom; Dittmer, Dirk P

    2013-04-01

    Kaposi sarcoma originates from endothelial cells and it is one of the most overt angiogenic tumors. In Sub-Saharan Africa, where HIV and the Kaposi sarcoma-associated herpesvirus (KSHV) are endemic, Kaposi sarcoma is the most common cancer overall, but model systems for disease study are insufficient. Here, we report the development of a novel mouse model of Kaposi sarcoma, where KSHV is retained stably and tumors are elicited rapidly. Tumor growth was sensitive to specific allosteric inhibitors (rapamycin, CCI-779, and RAD001) of the pivotal cell growth regulator mTOR. Inhibition of tumor growth was durable up to 130 days and reversible. mTOR blockade reduced VEGF secretion and formation of tumor vasculature. Together, the results show that mTOR inhibitors exert a direct anti-Kaposi sarcoma effect by inhibiting angiogenesis and paracrine effectors, suggesting their application as a new treatment modality for Kaposi sarcoma and other cancers of endothelial origin.

  17. Inhibition of N-acetylglucosaminyltransferase V enhances sensitivity of radiotherapy in human prostate cancer

    SciTech Connect

    Huang, Huiyi; Chen, Wenxia; Liu, Qiulian; Wei, Ting; Zhu, Weiliang; Meng, Hui; Guo, Linlang; Zhang, Jian

    2014-08-29

    Highlights: • We first evaluated the effect of GnT-V on radiation sensitivity of prostate cancer. • Higher level of GnT-V was detected more frequently in the PCa advanced tumors. • Attenuation of GnT-V inhibited cell proliferation, migration and increased apoptosis. • Knockdown of GnT-V could decrease radiation-induced G2/M arrest and NF-κB activity. • Inhibition of GnT-V may be involved in increasing radiation sensitivity of PCa cells. - Abstract: The purpose of this study was to investigate the relationship between N-acetylglucosaminyltransferase V (GnT-V) and radiation sensitivity of prostate cancer (PCa) cells both in vitro and in vivo. Firstly, the GnT-V expression was studied in 84 cases of PCa tissues, in which higher level of GnT-V was detected more frequently in the advanced tumors. Secondly, the GnT-V stably suppressed cell lines PCa/1079 (Lncap/1079 and PC3/1079) were constructed from PCa cell lines (Lncap and PC3) in vitro. Attenuation of GnT-V inhibited cell proliferation, migration and increased apoptosis, which resulted in enhanced radiation sensitivity of PCa cells. The underlying mechanism may be relevant to the increasing ratio of Bax/Bcl-2, the blocking transcription of NF-κB and the reduction of cell cycle G2-M arrest. Finally, in in vivo study, compared with control groups, the irradiated PCa xenograft nude mice of PCa/1079 indicated to reduce tumor-growth rate and enhance survival time. Summary, our studies showed that inhibition of GnT-V probably improved PCa cells’ radiation sensitivity.

  18. Inhibition of Nucleotide Synthesis Targets Brain Tumor Stem Cells in a Subset of Glioblastoma.

    PubMed

    Laks, Dan R; Ta, Lisa; Crisman, Thomas J; Gao, Fuying; Coppola, Giovanni; Radu, Caius G; Nathanson, David A; Kornblum, Harley I

    2016-06-01

    Inhibition of both the de novo (DNP) and salvage (NSP) pathways of nucleoside synthesis has been demonstrated to impair leukemia cells. We endeavored to determine whether this approach would be efficacious in glioblastoma. To diminish nucleoside biosynthesis, we utilized compound DI-39, which selectively targets NSP, in combination with thymidine (dT), which selectively targets DNP. We employed in vitro and ex vivo models to determine the effects of pretreatment with dT + DI-39 on brain tumor stem cells (BTSC). Here, we demonstrate that this combinatorial therapy elicits a differential response across a spectrum of human patient-derived glioblastoma cultures. As determined by apoptotic markers, most cultures were relatively resistant to treatment, although a subset was highly sensitive. Sensitivity was unrelated to S-phase delay and to DNA damage induced by treatment. Bioinformatics analysis indicated that response across cultures was associated with the transcription factor PAX3 (associated with resistance) and with canonical pathways, including the nucleotide excision repair pathway, PTEN (associated with resistance), PI3K/AKT (associated with sensitivity), and ErbB2-ErbB3. Our in vitro assays demonstrated that, in sensitive cultures, clonal sphere formation was reduced upon removal from pretreatment. In contrast, in a resistant culture, clonal sphere formation was slightly increased upon removal from pretreatment. Moreover, in an intracranial xenograft model, pretreatment of a sensitive culture caused significantly smaller and fewer tumors. In a resistant culture, tumors were equivalent irrespective of pretreatment. These results indicate that, in the subset of sensitive glioblastoma, BTSCs are targeted by inhibition of pyrimidine synthesis. Mol Cancer Ther; 15(6); 1271-8. ©2016 AACR. ©2016 American Association for Cancer Research.

  19. Sulindac sulfide selectively increases sensitivity of ABCC1 expressing tumor cells to doxorubicin and glutathione depletion.

    PubMed

    Whitt, Jason D; Keeton, Adam B; Gary, Bernard D; Sklar, Larry A; Sodani, Kamlesh; Chen, Zhe-Sheng; Piazza, Gary A

    2016-03-01

    ATP-binding cassette (ABC) transporters ABCC1 (MRP1), ABCB1 (P-gp), and ABCG2 (BCRP) contribute to chemotherapy failure. The primary goals of this study were to characterize the efficacy and mechanism of the nonsteroidal anti-inflammatory drug (NSAID), sulindac sulfide, to reverse ABCC1 mediated resistance to chemotherapeutic drugs and to determine if sulindac sulfide can influence sensitivity to chemotherapeutic drugs independently of drug efflux. Cytotoxicity assays were performed to measure resistance of ABC-expressing cell lines to doxorubicin and other chemotherapeutic drugs. NSAIDs were tested for the ability to restore sensitivity to resistance selected tumor cell lines, as well as a large panel of standard tumor cell lines. Other experiments characterized the mechanism by which sulindac sulfide inhibits ABCC1 substrate and co-substrate (GSH) transport in isolated membrane vesicles and intact cells. Selective reversal of multi-drug resistance (MDR), decreased efflux of doxorubicin, and fluorescent substrates were demonstrated by sulindac sulfide and a related NSAID, indomethacin, in resistance selected and engineered cell lines expressing ABCC1, but not ABCB1 or ABCG2. Sulindac sulfide also inhibited transport of leukotriene C4 into membrane vesicles. Sulindac sulfide enhanced the sensitivity to doxorubicin in 24 of 47 tumor cell lines, including all melanoma lines tested (7-7). Sulindac sulfide also decreased intracellular GSH in ABCC1 expressing cells, while the glutathione synthesis inhibitor, BSO, selectively increased sensitivity to sulindac sulfide induced cytotoxicity. Sulindac sulfide potently and selectively reverses ABCC1-mediated MDR at clinically achievable concentrations. ABCC1 expressing tumors may be highly sensitive to the direct cytotoxicity of sulindac sulfide, and in combination with chemotherapeutic drugs that induce oxidative stress.

  20. Sulindac sulfide selectively increases sensitivity of ABCC1 expressing tumor cells to doxorubicin and glutathione depletion

    PubMed Central

    Whitt, Jason D.; Keeton, Adam B.; Gary, Bernard D.; Sklar, Larry A.; Sodani, Kamlesh; Chen, Zhe-Sheng; Piazza, Gary A.

    2016-01-01

    Abstract ATP-binding cassette (ABC) transpo rters ABCC1 (MRP1), ABCB1 (P-gp), and ABCG2 (BCRP) contribute to chemotherapy failure. The primary goals of this study were to characterize the efficacy and mechanism of the non­steroidal anti-inflammatory drug (NSAID), sulindac sulfide, to reverse ABCC1 mediated resistance to chemother­apeutic drugs and to determine if sulindac sulfide can influence sensitivity to chemotherapeutic drugs independently of drug efflux. Cytotoxicity assays were performed to measure resistance of ABC-expressing cell lines to doxoru­bicin and other chemotherapeutic drugs. NSAIDs were tested for the ability to restore sensitivity to resistance selected tumor cell lines, as well as a large panel of standard tumor cell lines. Other experiments characterized the mechanism by which sulindac sulfide inhibits ABCC1 substrate and co-substrate (GSH) transport in isolated membrane vesicles and intact cells. Selective reversal of multi-drug resistance (MDR), decreased efflux of doxor­ubicin, and fluorescent substrates were demonstrated by sulindac sulfide and a related NSAID, indomethacin, in resistance selected and engineered cell lines expressing ABCC1, but not ABCB1 or ABCG2. Sulindac sulfide also inhibited transport of leukotriene C4 into membrane vesicles. Sulindac sulfide enhanced the sensitivity to doxoru­bicin in 24 of 47 tumor cell lines, including all melanoma lines tested (7-7). Sulindac sulfide also decreased intra­cellular GSH in ABCC1 expressing cells, while the glutathione synthesis inhibitor, BSO, selectively increased sensitivity to sulindac sulfide induced cytotoxicity. Sulindac sulfide potently and selectively reverses ABCC1-mediated MDR at clinically achievable concentrations. ABCC1 expressing tumors may be highly sensitive to the direct cytotoxicity of sulindac sulfide, and in combination with chemotherapeutic drugs that induce oxidative stress. PMID:28276667

  1. Inhibition of tumor energy pathways for targeted esophagus cancer therapy.

    PubMed

    Shafaee, Abbas; Dastyar, Davood Zarei; Islamian, Jalil Pirayesh; Hatamian, Milad

    2015-10-01

    Interest in targeting cancer metabolism has been renewed in recent years with the discovery that many cancer related pathways have a profound effect on metabolism and that many tumors become dependent on specific metabolic processes. Accelerated glucose uptake during anaerobic glycolysis and loss of regulation between glycolytic metabolism and respiration, are the major metabolic changes found in malignant cells. The non-metabolizable glucose analog, 2-deoxy-D-glucose inhibits glucose synthesis and adenosine triphosphate production. The adenosine monophosphate-activated protein kinase (AMPK) is a key sensor of cellular energy and AMPK is a potential target for cancer prevention and/or treatment. Metformin is an activator of AMPK which inhibits protein synthesis and gluconeogenesis during cellular stress. This article reviews the status of clinical and laboratory researches exploring targeted therapies via metabolic pathways for treatment of esophageal cancer.

  2. Checkpoint Inhibitor Sensitizes Human Tumor Cells | Center for Cancer Research

    Cancer.gov

    One unfortunate and detrimental side effect of ionizing radiation as a treatment for cancer is the damage it imparts to normal tissue near the targeted tumor. Technology has improved radiation delivery, minimizing the volume of normal tissue in the radiation field, but has not eliminated it completely. Thus, the identification of drugs that increase the sensitivity of cancer cells to radiation while sparing normal cells would go a long way toward improving patient quality of life and outcome.

  3. Noscapine sensitizes chemoresistant ovarian cancer cells to cisplatin through inhibition of HIF-1α.

    PubMed

    Su, Wenjing; Huang, Lei; Ao, Qilin; Zhang, Qinghua; Tian, Xun; Fang, Yong; Lu, Yunping

    2011-06-01

    Hypoxia-inducible factor 1 alpha (HIF-1α) is closely related with chemoresistance of solid tumors. The purpose of this study was to investigate the ability of noscapine to inhibit HIF-1α and sensitize ovarian cancer cells to cisplatin (DDP) under hypoxic conditions. Herein, we report that noscapine sensitized cobalt-induced chemoresistant ovarian cancer cells to DDP-induced apoptosis and inhibition of cell proliferation. Noscapine also promoted proteasome-mediated degradation of cobalt-stabilized HIF-1α protein, with subsequent inhibition of HIF-1 transcriptional activity. These data establish noscapine as a small molecule inhibitor of HIF-1α and provide an evidence for its combination with DDP in combating ovarian cancer chemoresistance.

  4. Tumor treating fields inhibit glioblastoma cell migration, invasion and angiogenesis

    PubMed Central

    Kim, Eun Ho; Song, Hyo Sook; Yoo, Seung Hoon; Yoon, Myonggeun

    2016-01-01

    Treatment with alternating electric fields at an intermediate frequency (100–300 kHz), referred to as tumor treating fields (TTF) therapy, inhibits cancer cell proliferation. In the present study, we demonstrated that TTF application suppressed the metastatic potential of U87 and U373 glioblastoma cell lines via the NF-kB, MAPK and PI3K/AKT signaling pathways. Wound-healing and transwell assays showed that TTF suppressed cell migration and invasion compared with controls. Soft agar and three-dimensional culture assays showed that TTF inhibited both anchorage-dependent (cell proliferation) and anchorage-independent (colony formation) GBM cell growth. TTF dysregulated epithelial-to-mesenchymal transition-related genes, such as vimentin and E-cadherin, which partially accounted for TTF inhibition of cell migration and invasion. We further demonstrated that TTF application suppressed angiogenesis by downregulating VEGF, HIF1α and matrix metalloproteinases 2 and 9. TTF also inhibited NF-kB transcriptional activity. Collectively, our findings show that TTF represents a promising novel anti-invasion and anti-angiogenesis therapeutic strategy for use in GBM patients. PMID:27556184

  5. Antitumor effects of hyaluronan inhibition in desmoid tumors.

    PubMed

    Briggs, Alexandra; Rosenberg, Laura; Buie, Justin D; Rizvi, Hira; Bertagnolli, Monica M; Cho, Nancy L

    2015-02-01

    Desmoid tumors (DTs) are rare, mesenchymal tumors that exhibit features of an abundant wound healing process. Previously, we showed that mesenchymal stem cells (MSCs) are constituents of DTs and may contribute to desmoid tumorigenesis via activities associated with wound healing. Hyaluronan (HA) is a long-charged chain of repeating glucuronate and N-acetylglucosamine disaccharides that is synthesized by HA synthases (HAS) and degraded by hyaluronidases (HYAL). HA is secreted into the extracellular matrix by injured stroma and is important for normal tissue repair and neoplastic progression. Here, we investigated the presence of HA in DTs and the antitumor effects of the HA inhibitor, 4-methylumbelliferone (4-MU), on DT-derived mesenchymal cells. By immunohistochemistry and enzyme-linked immunosorbent assay, we found abundant expression of HA in 29/30 DTs as well as >5-fold increased HA levels in DT-derived cell lines relative to controls. Immunohistochemistry also demonstrated high expression of HAS2 in DTs, and quantitative PCR analysis showed increased HAS2 upregulation in frozen DTs and DT-derived cells. 4-MU treatment of DT-derived cells significantly decreased proliferation as well as HA and HAS2 levels. Fluorescent immunohistochemistry showed that MSCs in DTs coexpressed HA, HAS2, HYAL2, as well as the major HA receptor CD44 and HA coreceptor TLR4. Taken together, our results suggest that paracrine regulation of HA signaling in DTs may contribute to MSC recruitment and tumor proliferation. Future studies investigating the role of HA in tumor-stroma crosstalk and inhibition of HA-MSC interactions as a novel therapeutic target in DTs and other solid tumors are warranted.

  6. Inhibition of Notch Signaling in Combination with Paclitaxel Reduces Platinum-Resistant Ovarian Tumor Growth

    PubMed Central

    Groeneweg, Jolijn W.; DiGloria, Celeste M.; Yuan, Jing; Richardson, William S.; Growdon, Whitfield B.; Sathyanarayanan, Sriram; Foster, Rosemary; Rueda, Bo R.

    2014-01-01

    Introduction: Ovarian cancer (OvCa) is the most lethal gynecologic malignancy in the United States because of chemoresistant recurrent disease. Our objective was to investigate the efficacy of inhibiting the Notch pathway with a γ-secretase inhibitor (GSI) in an OvCa patient-derived xenograft model as a single agent therapy and in combination with standard chemotherapy. Methods: Immunocompromised mice bearing xenografts derived from clinically platinum-sensitive human ovarian serous carcinomas were treated with vehicle, GSI (MRK-003) alone, paclitaxel and carboplatin (P/C) alone, or the combination of GSI and P/C. Mice bearing platinum-resistant xenografts were given GSI with or without paclitaxel. Gene transcript levels of the Notch pathway target Hes1 were analyzed using RT-PCR. Notch1 and Notch3 protein levels were evaluated. The Wilcoxon rank-sum test was used to assess significance between the different treatment groups. Results: Expression of Notch1 and 3 was variable. GSI alone decreased tumor growth in two of three platinum-sensitive ovarian tumors (p < 0.05), as well as in one of three platinum-sensitive tumors (p = 0.04). The combination of GSI and paclitaxel was significantly more effective than GSI alone and paclitaxel alone in all platinum-resistant ovarian tumors (all p < 0.05). The addition of GSI did not alter the effect of P/C in platinum-sensitive tumors. Interestingly, although the response of each tumor to chronic GSI exposure did not correlate with its endogenous level of Notch expression, GSI did negatively affect Notch signaling in an acute setting. Conclusion: Inhibiting the Notch signaling cascade with a GSI reduces primary human xenograft growth in vivo. GSI synergized with conventional cytotoxic chemotherapy only in the platinum-resistant OvCa models with single agent paclitaxel. These findings suggest inhibition of the Notch pathway in concert with taxane therapy may hold promise for treatment of platinum-resistant Ov

  7. IGF-1R inhibition in mammary epithelia promotes canonical Wnt signaling and Wnt1-driven tumors

    PubMed Central

    Rota, Lauren M.; Albanito, Lidia; Shin, Marcus E.; Goyeneche, Corey L.; Shushanov, Sain; Gallagher, Emily J.; LeRoith, Derek; Lazzarino, Deborah A.; Wood, Teresa L.

    2014-01-01

    Triple-negative breast cancers (TNBC) are an aggressive disease subtype which unlike other subtypes lack an effective targeted therapy. Inhibitors of the insullin-like growth factor receptor (IGF-1R) have been considered for use in treating TNBC. Here we provide genetic evidence that IGF-1R inhibition promotes development of Wnt1-mediated murine mammary tumors that offer a model of TNBC. We found that in a double transgenic mouse model carrying activated Wnt-1 and mutant IGF-1R, a reduction in IGF-1R signaling reduced tumor latency and promoted more aggressive phenotypes. These tumors displayed a squamal cell phenotype with increased expression of keratins 5/6 and β-catenin. Notably, cell lineage analyses revealed an increase in basal (CD29hi/CD24+) and luminal (CD24+/CD61+/CD29lo) progenitor cell populations, along with increased Nanog expression and decreased Elf5 expression. In these doubly transgenic mice, lung metastases developed with characteristics of the primary tumors, unlike MMTV-Wnt1 mice. Mechanistic investigations showed that pharmacological inhibition of the IGF-1R in vitro was sufficient to increase the tumorsphere-forming efficiency of MMTV-Wnt1 tumor cells. Tumors from doubly transgenic mice also exhibited an increase in the expression ratio of the IGF-II-sensitive, A isoform of the insulin receptor vs the IR-B isoform, which in vitro resulted in enhanced expression of β-catenin. Overall, our results revealed that in Wnt-driven tumors an attenuation of IGF-1R signaling accelerates tumorigenesis and promotes more aggressive phenotypes, with potential implications for understanding TNBC pathobiology and treatment. PMID:25092896

  8. The dietary flavonoid apigenin sensitizes malignant tumor cells to tumor necrosis factor-related apoptosis-inducing ligand.

    PubMed

    Horinaka, Mano; Yoshida, Tatsushi; Shiraishi, Takumi; Nakata, Susumu; Wakada, Miki; Sakai, Toshiyuki

    2006-04-01

    Dietary flavonoid apigenin is expected to have preventive and therapeutic potential against malignant tumors. In this report, we show for the first time that apigenin markedly induces the expression of death receptor 5 (DR5) and synergistically acts with exogenous soluble recombinant human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to induce apoptosis in malignant tumor cells. TRAIL is a promising candidate for cancer therapeutics due to its ability to selectively induce apoptosis in cancer cells. The combined use of apigenin and TRAIL at suboptimal concentrations induces Bcl-2-interacting domain cleavage and the activation of caspases-8, -10, -9, and -3. Furthermore, human recombinant DR5/Fc chimera protein and caspase inhibitors dramatically inhibit apoptosis induced by the combination of apigenin and TRAIL. On the other hand, apigenin-mediated induction of DR5 expression is not observed in normal human peripheral blood mononuclear cells. Moreover, apigenin does not sensitize normal human peripheral blood mononuclear cells to TRAIL-induced apoptosis. These results suggest that this combined treatment with apigenin and TRAIL might be promising as a new therapy against malignant tumors.

  9. Sensitive Detection of Viral Transcripts in Human Tumor Transcriptomes

    PubMed Central

    Schelhorn, Sven-Eric; Fischer, Matthias; Tolosi, Laura; Altmüller, Janine; Nürnberg, Peter; Pfister, Herbert; Lengauer, Thomas; Berthold, Frank

    2013-01-01

    In excess of % of human cancer incidents have a viral cofactor. Epidemiological studies of idiopathic human cancers indicate that additional tumor viruses remain to be discovered. Recent advances in sequencing technology have enabled systematic screenings of human tumor transcriptomes for viral transcripts. However, technical problems such as low abundances of viral transcripts in large volumes of sequencing data, viral sequence divergence, and homology between viral and human factors significantly confound identification of tumor viruses. We have developed a novel computational approach for detecting viral transcripts in human cancers that takes the aforementioned confounding factors into account and is applicable to a wide variety of viruses and tumors. We apply the approach to conducting the first systematic search for viruses in neuroblastoma, the most common cancer in infancy. The diverse clinical progression of this disease as well as related epidemiological and virological findings are highly suggestive of a pathogenic cofactor. However, a viral etiology of neuroblastoma is currently contested. We mapped transcriptomes of neuroblastoma as well as positive and negative controls to the human and all known viral genomes in order to detect both known and unknown viruses. Analysis of controls, comparisons with related methods, and statistical estimates demonstrate the high sensitivity of our approach. Detailed investigation of putative viral transcripts within neuroblastoma samples did not provide evidence for the existence of any known human viruses. Likewise, de-novo assembly and analysis of chimeric transcripts did not result in expression signatures associated with novel human pathogens. While confounding factors such as sample dilution or viral clearance in progressed tumors may mask viral cofactors in the data, in principle, this is rendered less likely by the high sensitivity of our approach and the number of biological replicates analyzed. Therefore, our

  10. On-target Inhibition of Tumor Fermentative Glycolysis as Visualized by Hyperpolarized Pyruvate1

    PubMed Central

    Seth, Pankaj; Grant, Aaron; Tang, Jian; Vinogradov, Elena; Wang, Xioaen; Lenkinski, Robert; Sukhatme, Vikas P

    2011-01-01

    Many cancer cells display the Warburg effect, that is, enhanced glycolysis followed by fermentation (conversion of pyruvate to lactate). Recently, the molecular basis for these effects has started to be elucidated, and the up-regulation of the lactate dehydrogenase A (LDH-A) isoform of lactate dehydrogenase is felt to be a major molecular mediator of this phenomenon. Moreover, LDH-A expression in tumor tissue and LDH-A levels in blood portend a bad prognosis, and LDH-A blockade can lead to tumor growth inhibition in tumor transplant models. We have extended existing data (some of which were published during the time when we were carrying out our studies) in two important ways: 1) inhibition of LDH-A in a glycolytic lung cancer cell line results in reactive oxygen species-mediated apoptosis and increased sensitivity to the chemotherapeutic drug paclitaxel and 2) inhibition of fermentative glycolysis can also be accomplished by activation of the pyruvate dehydrogenase complex by the drug dichloroacetate, now undergoing clinical trials, and that this phenomenon can be monitored in vivo in a noninvasive real-time manner through magnetic resonance spectroscopy using hyperpolarized pyruvate. Collectively, these data suggest that in vivo effects of drugs that redirect the fate of pyruvate, and hence are aimed at reversing the Warburg effect, could be monitored through the use of hyperpolarized magnetic resonance spectroscopy, a method that is scalable to human use. PMID:21245941

  11. [A novel HIF-1 inhibitor--manassantin A derivative LXY6099 inhibits tumor growth].

    PubMed

    Lai, Fang-Fang; Liu, Xiao-Yu; Niu, Fei; Lang, Li-Wei; Xie, Ping; Chen, Xiao-Guang

    2014-05-01

    Hypoxia-inducible factor-1 (HIF-1) is a key transcription factor on hypoxia responses in mammalian tissues. HIF-1 plays as a positive factor in solid tumor and leads to hypoxia-driven responses that enhance its downstream gene expression for tumor growth and survival. LXY6099 was obtained by the structural modification and optimization of manassantin A (MA) as a high potent HIF-1 inhibitor. Antitumor activity of LXY6099 was observed in this study. LXY6099 with an IC50 value of 2.46 x 10(-10) mol x L(-1) showed more sensitive inhibition activity to HIF-1 than that of MA detected by reporter gene assay (> 100 folds). It showed strong inhibition on the growth of human solid tumor cell lines. Furthermore, LXY6099 exhibited significant antitumor activity against established human tumor xenografts in nu/nu mice with treatment of MX-1 breast cancer. Thus, LXY6099 as a novel HIF-1 inhibitor could be further developed into anti-cancer agents.

  12. Effects of Pluronic and Doxorubicin on Drug Uptake, Cellular Metabolism, Apoptosis and Tumor Inhibition in Animal Models of MDR Cancers

    PubMed Central

    Batrakova, Elena V.; Li, Shu; Brynskikh, Anna M.; Sharma, Amit K.; Li, Yili; Boska, Michael; Gong, Nan; Mosley, R. Lee; Alakhov, Valery Yu.; Gendelman, Howard E.; Kabanov, Alexander V.

    2011-01-01

    Cancer chemotherapy is believed to be impeded by multidrug resistance (MDR). Pluronic (triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), PEO-b-PPO-b-PEO) were previously shown to sensitize MDR tumors to antineoplastic agents. This study uses animal models of Lewis lung carcinoma (3LL-M27) and T-lymphocytic leukemia (P388/ADR and P388) derived solid tumors to delineate mechanisms of sensitization of MDR tumors by Pluronic P85 (P85) in vivo. First, non-invasive single photon emission computed tomography (SPECT) and tumor tissue radioactivity sampling demonstrate that intravenous co-administration of P85 with a Pgp-substrate, 99Tc-sestamibi, greatly increases the tumor uptake of this substrate in the MDR tumors. Second, 31P magnetic resonance spectroscopy (31P-MRS) in live animals and tumor tissue sampling for ATP suggest that P85 and doxorubicin (Dox) formulations induce pronounced ATP depletion in MDR tumors. Third, these formulations are shown to increase tumor apoptosis in vivo by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and reverse transcription polymerase chain reaction (RT-PCR) for caspases 8 and 9. Altogether, formulation of Dox with P85 results in increased inhibition of the growth solid tumors in mice and represents novel and promising strategy for therapy of drug resistant cancers. PMID:20074598

  13. Calmodulin inhibition contributes to sensitize TRAIL-induced apoptosis in human lung cancer H1299 cells.

    PubMed

    Hwang, Mi-kyung; Min, Yong Ki; Kim, Seong Hwan

    2009-12-01

    Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) preferentially triggers apoptosis in tumor cells versus normal cells. However, TRAIL alone is not effective in treating TRAIL-resistant tumors. We evaluated the effect of 180 enzyme inhibitors on TRAIL-induced apoptosis in human lung cancer H1299 cells, and found fluphenazine-N-2-chloroethane (a calmodulin (CaM) antagonist) sensitized TRAIL-induced apoptosis. Interestingly, in the presence of TRAIL, it increased caspase-8 binding to the Fas-associated death domain (FADD), but decreased binding of FADD-like interleukin-1beta-converting enzyme inhibitory proteins (FLIPs). Additionally, its combination with TRAIL inhibited Akt phosphorylation. These results were consistently observed in cells treated with CaM siRNA. We suggested the blockade of CaM could sensitize lung cancer cells to TRAIL-induced apoptosis in at least 2 ways: (i) it can activate death-inducing signaling complex mediated apoptosis by inhibiting TRAIL-induced binding of FLIP and TRAIL-enhanced binding of caspase-8 to FADD; (ii) it can inhibit Akt phosphorylation, consequently leading to decreased expression of anti-apoptotic molecules such as FLIP and members of the inhibitor of apoptosis protein family. This study suggests the combination of CaM antagonists with TRAIL may have the therapeutic potential to overcome the resistance of lung cancers to apoptosis.

  14. Aloe emodin inhibits the cytotoxic action of tumor necrosis factor.

    PubMed

    Harhaji, Ljubica; Mijatovic, Sanja; Maksimovic-Ivanic, Danijela; Popadic, Dusan; Isakovic, Aleksandra; Todorovic-Markovic, Biljana; Trajkovic, Vladimir

    2007-07-30

    We demonstrate the capacity of an herbal anthraquinone aloe emodin to reduce the cytotoxicity of the proinflammatory cytokine tumor necrosis factor (TNF) towards L929 mouse fibrosarcoma and U251 human glioma cell lines. Aloe emodin inhibited both TNF-induced cell necrosis and apoptosis, but it did not reduce cell death induced by UV radiation or hydrogen peroxide. Aloe emodin inhibited both basal and TNF-triggered activation of extracellular signal-regulated kinase (ERK), and a selective blockade of ERK activation mimicked the cytoprotective action of the drug. On the other hand, aloe emodin did not affect TNF-induced activation of p38 mitogen-activated protein kinase or generation of reactive oxygen species. The combination of aloe emodin and TNF caused an intracellular appearance of acidified autophagic vesicles, and the inhibition of autophagy with bafilomycin or 3-methyladenine efficiently blocked the cytoprotective action of aloe emodin. These data indicate that aloe emodin could prevent TNF-triggered cell death through mechanisms involving induction of autophagy and blockade of ERK activation.

  15. Dependence On Glycolysis Sensitizes BRAF-mutated Melanomas For Increased Response To Targeted BRAF Inhibition

    PubMed Central

    Hardeman, Keisha N.; Peng, Chengwei; Paudel, Bishal B.; Meyer, Christian T.; Luong, Thong; Tyson, Darren R.; Young, Jamey D.; Quaranta, Vito; Fessel, Joshua P.

    2017-01-01

    Dysregulated metabolism can broadly affect therapy resistance by influencing compensatory signaling and expanding proliferation. Given many BRAF-mutated melanoma patients experience disease progression with targeted BRAF inhibitors, we hypothesized therapeutic response is related to tumor metabolic phenotype, and that altering tumor metabolism could change therapeutic outcome. We demonstrated the proliferative kinetics of BRAF-mutated melanoma cells treated with the BRAF inhibitor PLX4720 fall along a spectrum of sensitivity, providing a model system to study the interplay of metabolism and drug sensitivity. We discovered an inverse relationship between glucose availability and sensitivity to BRAF inhibition through characterization of metabolic phenotypes using nearly a dozen metabolic parameters in Principle Component Analysis. Subsequently, we generated rho0 variants that lacked functional mitochondrial respiration and increased glycolytic metabolism. The rho0 cell lines exhibited increased sensitivity to PLX4720 compared to the respiration-competent parental lines. Finally, we utilized the FDA-approved antiretroviral drug zalcitabine to suppress mitochondrial respiration and to force glycolysis in our cell line panel, resulting in increased PLX4720 sensitivity via shifts in EC50 and Hill slope metrics. Our data suggest that forcing tumor glycolysis in melanoma using zalcitabine or other similar approaches may be an adjunct to increase the efficacy of targeted BRAF therapy. PMID:28205616

  16. Estrogen inhibits the effects of obesity and alcohol on mammary tumors and fatty liver.

    PubMed

    Hong, Jina; Holcomb, Valerie B; Kushiro, Kyoko; Núñez, Nomelí P

    2011-12-01

    The risk of developing breast cancer and fatty liver is increased by alcohol consumption. The objective of the present study was to determine if obesity and exogenous estrogen supplementation alter the effects of alcohol on mammary tumorigenesis and fatty liver. Ovariectomized female mice were (1) fed diets to induce overweight and obese phenotypes, (2) provided water or 20% alcohol, (3) implanted with placebo, low- or high-dose estrogen pellets and (4) injected with Met-1 mouse mammary cancer cells. Alcohol-consuming mice were more insulin sensitive and developed larger tumors than water consuming mice. Obese mice developed slightly larger tumors than control mice. Alcohol consumption and obesity increased growth factors, hepatic steatosis, activation of Akt, and inhibited the caspase-3 cascade. Estrogen treatment triggered the loss of body fat, induced insulin sensitivity, suppressed tumor growth, reduced growth factors and improved hepatic steatosis. Results show that the effects of alcohol on mammary tumor and fatty liver are modified by obesity and estrogen supplementation.

  17. Inhibition of hydrogen sulfide biosynthesis sensitizes lung adenocarcinoma to chemotherapeutic drugs by inhibiting mitochondrial DNA repair and suppressing cellular bioenergetics

    PubMed Central

    Szczesny, Bartosz; Marcatti, Michela; Zatarain, John R.; Druzhyna, Nadiya; Wiktorowicz, John E.; Nagy, Péter; Hellmich, Mark R.; Szabo, Csaba

    2016-01-01

    Therapeutic manipulation of the gasotransmitter hydrogen sulfide (H2S) has recently been proposed as a novel targeted anticancer approach. Here we show that human lung adenocarcinoma tissue expresses high levels of hydrogen sulfide (H2S) producing enzymes, namely, cystathionine beta-synthase (CBS), cystathionine gamma lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST), in comparison to adjacent lung tissue. In cultured lung adenocarcinoma but not in normal lung epithelial cells elevated H2S stimulates mitochondrial DNA repair through sulfhydration of EXOG, which, in turn, promotes mitochondrial DNA repair complex assembly, thereby enhancing mitochondrial DNA repair capacity. In addition, inhibition of H2S-producing enzymes suppresses critical bioenergetics parameters in lung adenocarcinoma cells. Together, inhibition of H2S-producing enzymes sensitize lung adenocarcinoma cells to chemotherapeutic agents via induction of mitochondrial dysfunction as shown in in vitro and in vivo models, suggesting a novel mechanism to overcome tumor chemoresistance. PMID:27808278

  18. Salvinorin A Inhibits Airway Hyperreactivity Induced by Ovalbumin Sensitization.

    PubMed

    Rossi, Antonietta; Caiazzo, Elisabetta; Bilancia, Rossella; Riemma, Maria A; Pagano, Ester; Cicala, Carla; Ialenti, Armando; Zjawiony, Jordan K; Izzo, Angelo A; Capasso, Raffaele; Roviezzo, Fiorentina

    2016-01-01

    Salvinorin A, a neoclerodane diterpene isolated from Salvia divinorum, exerts a number of pharmacological actions which are not solely limited to the central nervous system. Recently it has been demonstrated that Salvinorin A inhibits acute inflammatory response affecting leukotriene (LT) production. Since LTs are potent lipid mediators implicated in allergic diseases, we evaluated the effect of Salvinorin A on allergic inflammation and on airways following sensitization in the mouse. Mice were sensitized with s.c. injection of ovalbumin (OVA) on days 1 and 8. Sensitized mice received on days 9 and 12 on the shaved dorsal surface air administration to induce the development of the air-pouches. On day 15 animals were challenged by injection of OVA into the air-pouch. Salvinorin A, administered (10 mg/kg) before each allergen exposure, significantly reduced OVA-induced LT increase in the air pouch. This effect was coupled to a reduction in cell recruitment and Th2 cytokine production. In another set of experiments, mice were sensitized with OVA and both bronchial reactivity and pulmonary inflammation were assessed. Salvinorin A abrogated bronchial hyperreactivity and interleukin (IL)-13 production, without effect on pulmonary inflammation. Indeed cell infiltration and peribronchial edema were still present following diterpenoid treatment. Similarly, pulmonary IL-4 and plasmatic IgE levels were not modulated. Conversely, Salvinorin A significantly reduced LTC4 production in the lung of sensitized mice. Finally mast cell activity was evaluated by means of toluidine blue staining. Data obtained evidenced that Salvinorin A significantly inhibited mast cell degranulation in the lung. Our study demonstrates that Salvinorin A inhibits airway hyperreactivity induced by sensitization by inhibition of LT production and mast cell degranulation. In conclusion Salvinorin A could represent a promising candidate for drug development in allergic diseases such as asthma.

  19. Salvinorin A Inhibits Airway Hyperreactivity Induced by Ovalbumin Sensitization

    PubMed Central

    Rossi, Antonietta; Caiazzo, Elisabetta; Bilancia, Rossella; Riemma, Maria A.; Pagano, Ester; Cicala, Carla; Ialenti, Armando; Zjawiony, Jordan K.; Izzo, Angelo A.; Capasso, Raffaele; Roviezzo, Fiorentina

    2017-01-01

    Salvinorin A, a neoclerodane diterpene isolated from Salvia divinorum, exerts a number of pharmacological actions which are not solely limited to the central nervous system. Recently it has been demonstrated that Salvinorin A inhibits acute inflammatory response affecting leukotriene (LT) production. Since LTs are potent lipid mediators implicated in allergic diseases, we evaluated the effect of Salvinorin A on allergic inflammation and on airways following sensitization in the mouse. Mice were sensitized with s.c. injection of ovalbumin (OVA) on days 1 and 8. Sensitized mice received on days 9 and 12 on the shaved dorsal surface air administration to induce the development of the air-pouches. On day 15 animals were challenged by injection of OVA into the air-pouch. Salvinorin A, administered (10 mg/kg) before each allergen exposure, significantly reduced OVA-induced LT increase in the air pouch. This effect was coupled to a reduction in cell recruitment and Th2 cytokine production. In another set of experiments, mice were sensitized with OVA and both bronchial reactivity and pulmonary inflammation were assessed. Salvinorin A abrogated bronchial hyperreactivity and interleukin (IL)-13 production, without effect on pulmonary inflammation. Indeed cell infiltration and peribronchial edema were still present following diterpenoid treatment. Similarly, pulmonary IL-4 and plasmatic IgE levels were not modulated. Conversely, Salvinorin A significantly reduced LTC4 production in the lung of sensitized mice. Finally mast cell activity was evaluated by means of toluidine blue staining. Data obtained evidenced that Salvinorin A significantly inhibited mast cell degranulation in the lung. Our study demonstrates that Salvinorin A inhibits airway hyperreactivity induced by sensitization by inhibition of LT production and mast cell degranulation. In conclusion Salvinorin A could represent a promising candidate for drug development in allergic diseases such as asthma. PMID

  20. Inhibition of glutamine metabolism counteracts pancreatic cancer stem cell features and sensitizes cells to radiotherapy.

    PubMed

    Li, Doudou; Fu, Zhiqiang; Chen, Ruiwan; Zhao, Xiaohui; Zhou, Yu; Zeng, Bing; Yu, Min; Zhou, Quanbo; Lin, Qing; Gao, Wenchao; Ye, Huilin; Zhou, Jiajia; Li, Zhihua; Liu, Yimin; Chen, Rufu

    2015-10-13

    Pancreatic ductal adenocarcinoma (PDAC) cells utilize a novel non-canonical pathway of glutamine metabolism that is essential for tumor growth and redox balance. Inhibition of this metabolic pathway in PDAC can potentially synergize with therapies that increase intracellular reactive oxygen species (ROS) such as radiation. Here, we evaluated the dependence of pancreatic cancer stem cells (PCSCs) on this non-canonical glutamine metabolism pathway and researched whether inhibiting this pathway can enhance radiosensitivity of PCSCs. We showed that glutamine deprivation significantly inhibited self-renewal, decreased expression of stemness-related genes, increased intracellular ROS, and induced apoptosis in PCSCs. These effects were countered by oxaloacetate, but not α-ketoglutarate. Knockdown of glutamic-oxaloacetic transaminase dramatically impaired PCSCs properties, while glutamate dehydrogenase knockdown had a limited effect, suggesting a dependence of PCSCs on non-canonical glutamine metabolism. Additionally, glutamine deprivation significantly increased radiation-induced ROS and sensitized PCSCs to fractionated radiation. Moreover, transaminase inhibitors effectively enhanced ROS generation, promoted radiation sensitivity, and attenuated tumor growth in nude mice following radiation exposure. Our findings reveal that inhibiting the non-canonical pathway of glutamine metabolism enhances the PCSC radiosensitivity and may be an effective adjunct in cancer radiotherapy.

  1. Galectin-3 inhibition sensitizes human renal cell carcinoma cells to arsenic trioxide treatment

    PubMed Central

    Xu, Yangyang; Gu, Xin; Gong, Mancheng; Guo, Guiying; Han, Kaiyu; An, Ruihua

    2013-01-01

    The anti-tumor effects of arsenic trioxide (ATO) were well established in acute promyelocytic leukemia, but not in renal cell carcinoma (RCC). Recent evidences indicate that galectin-3 (Gal-3) plays an anti-apoptotic role in chemotherapy induced tumor cell death. This study was intended to clarify the exact roles of Gal-3 performed in ATO-induced apoptosis in RCC cells. Weak apoptosis was observed in Gal-3-positive RCC cells (Caki-1, Caki-2, 786-0, and ACHN) following ATO treatment. However, ATO treatment upregulated Gal-3 expression concurrently caused a Synexin-cooperated translocation of Gal-3 from the nucleus to the cytoplasm. Gal-3-knockdown cells were more sensitive to ATO treatment as indicated by a strong mitochondria-dependent apoptosis following ATO treatment. Meanwhile, Gal-3 was found to inhibit ATO-induced apoptosis through enhancing Bcl-2 expression and stabilizing mitochondria. To confirm the results obtained from genetic method, we employed a Gal-3 inhibitor, modified citrus prectin (MCP), and co-treated the RCC cells with ATO. The cells showed an increased apoptosis in the syngeneic application of Gal-3 inhibition and ATO compared with ATO application alone. Based on these results, we conclude that Gal-3 inhibition sensitizes human renal cell carcinoma cells to ATO treatment through increasing mitochondria-dependent apoptosis. Our studies implicate synergetic application of ATO and Gal-3 inhibition as a potential strategy for RCC treatment. PMID:23917726

  2. AKT Inhibition in Solid Tumors With AKT1 Mutations.

    PubMed

    Hyman, David M; Smyth, Lillian M; Donoghue, Mark T A; Westin, Shannon N; Bedard, Philippe L; Dean, Emma J; Bando, Hideaki; El-Khoueiry, Anthony B; Pérez-Fidalgo, José A; Mita, Alain; Schellens, Jan H M; Chang, Matthew T; Reichel, Jonathan B; Bouvier, Nancy; Selcuklu, S Duygu; Soumerai, Tara E; Torrisi, Jean; Erinjeri, Joseph P; Ambrose, Helen; Barrett, J Carl; Dougherty, Brian; Foxley, Andrew; Lindemann, Justin P O; McEwen, Robert; Pass, Martin; Schiavon, Gaia; Berger, Michael F; Chandarlapaty, Sarat; Solit, David B; Banerji, Udai; Baselga, José; Taylor, Barry S

    2017-07-10

    Purpose AKT1 E17K mutations are oncogenic and occur in many cancers at a low prevalence. We performed a multihistology basket study of AZD5363, an ATP-competitive pan-AKT kinase inhibitor, to determine the preliminary activity of AKT inhibition in AKT-mutant cancers. Patients and Methods Fifty-eight patients with advanced solid tumors were treated. The primary end point was safety; secondary end points were progression-free survival (PFS) and response according to Response Evaluation Criteria in Solid Tumors (RECIST). Tumor biopsies and plasma cell-free DNA (cfDNA) were collected in the majority of patients to identify predictive biomarkers of response. Results In patients with AKT1 E17K-mutant tumors (n = 52) and a median of five lines of prior therapy, the median PFS was 5.5 months (95% CI, 2.9 to 6.9 months), 6.6 months (95% CI, 1.5 to 8.3 months), and 4.2 months (95% CI, 2.1 to 12.8 months) in patients with estrogen receptor-positive breast, gynecologic, and other solid tumors, respectively. In an exploratory biomarker analysis, imbalance of the AKT1 E17K-mutant allele, most frequently caused by copy-neutral loss-of-heterozygosity targeting the wild-type allele, was associated with longer PFS (hazard ratio [HR], 0.41; P = .04), as was the presence of coincident PI3K pathway hotspot mutations (HR, 0.21; P = .045). Persistent declines in AKT1 E17K in cfDNA were associated with improved PFS (HR, 0.18; P = .004) and response ( P = .025). Responses were not restricted to patients with detectable AKT1 E17K in pretreatment cfDNA. The most common grade ≥ 3 adverse events were hyperglycemia (24%), diarrhea (17%), and rash (15.5%). Conclusion This study provides the first clinical data that AKT1 E17K is a therapeutic target in human cancer. The genomic context of the AKT1 E17K mutation further conditioned response to AZD5363.

  3. Telomerase inhibition impairs tumor growth in glioblastoma xenografts.

    PubMed

    Falchetti, Maria Laura; Fiorenzo, Paolo; Mongiardi, Maria Patrizia; Petrucci, Giovanna; Montano, Nicola; Maira, Giulio; Pierconti, Francesco; Larocca, Luigi Maria; Levi, Andrea; Pallini, Roberto

    2006-07-01

    Telomerase is a specialized DNA polymerase that is required to replicate the ends of linear chromosomes, the telomeres. The majority of human cancers express high levels of telomerase activity that is permissive for tumor growth because it provides cells with an extended proliferative potential. Additionally, telomerase exerts cell growth promoting functions and favors cell survival. Human glioblastoma multiforme (GBM) cells express high level of telomerase activity owing to the overexpression of human telomerase reverse transcriptase (hTERT), the limiting subunit of the enzyme. Here we used retroviral mediated RNA interference to dampen down telomerase activity in two distinct human GBM cell lines, U87MG and TB10. Substantial decrease of hTERT mRNA and telomerase activity had only minimal effects on telomere length maintenance, cell growth and survival in vitro. On the contrary, development of tumors upon subcutaneously grafting of U87MG and TB10 cells and intracranial implantation of U87MG cells in nude athymic mice was strongly reduced by telomerase inhibition.

  4. Fulvestrant, a selective estrogen receptor down-regulator, sensitizes estrogen receptor negative breast tumors to chemotherapy.

    PubMed

    Jiang, Donghai; Huang, Yuan; Han, Ning; Xu, Mingjie; Xu, Liang; Zhou, Lin; Wang, Shu; Fan, Weimin

    2014-05-01

    Drug resistance frequently results in poor prognosis and high 5-year recurrence rate in estrogen receptor-negative (ER-) breast cancer patients. Herein, we examined the reversal effects of fulvestrant on multidrug resistance (MDR) in ER- breast cancer cells. Co-administration of fulvestrant significantly sensitized ER- MDR tumors to paclitaxel both in vitro and in vivo. Further analyses indicated that fulvestrant did not affect P-gp expression, but could inhibit P-gp function and subsequently reverse P-gp mediated drug resistance in ER- breast cancer cells. These results showed that combination of fulvestrant and chemotherapeutic agents might provide an effective treatment for ER- MDR breast cancers.

  5. The role of DNA polymerase β in determining sensitivity to ionizing radiation in human tumor cells

    PubMed Central

    Vens, Conchita; Dahmen-Mooren, Els; Verwijs-Janssen, Manon; Blyweert, Wim; Graversen, Lise; Bartelink, Harry; Begg, Adrian C.

    2002-01-01

    Lethal lesions after ionizing radiation are thought to be mainly unrepaired or misrepaired DNA double-strand breaks, ultimately leading to lethal chromosome aberrations. However, studies with radioprotectors and repair inhibitors indicate that single-strand breaks, damaged nucleotides or abasic sites can also influence cell survival. This paper reports on studies to further define the role of base damage and base excision repair on the radiosensitivity of human cells. We retrovirally transduced human tumor cells with a dominant negative form of DNA polymerase β, comprising the 14 kDa DNA-binding domain of DNA polymerase β but lacking polymerase function. Radiosensitization of two human carcinoma cell lines, A549 and SQD9, was observed, achieving dose enhancement factors of 1.5–1.7. Sensitization was dependent on expression level of the dominant negative and was seen in both single cell clones and in unselected virally transduced populations. Sensitization was not due to changes in cell cycle distribution. Little or no sensitization was seen in G1-enriched populations, indicating cell cycle specificity for the observed sensitization. These results contrast with the lack of effect seen in DNA polymerase β knockout cells, suggesting that polDN also inhibits the long patch, DNA polymerase β-independent repair pathway. These data demonstrate an important role for BER in determining sensitivity to ionizing radiation and might help identify targets for radiosensitizing tumor cells. PMID:12087186

  6. Relationship between laminin binding capacity and laminin expression on tumor cells sensitive or resistant to natural cell-mediated cytotoxicity

    SciTech Connect

    Laybourn, K.A.; Varani, J.; Fligiel, S.E.G.; Hiserodt, J.C.

    1986-03-01

    Previous studies have identified the presence of laminin binding sites on murine NK and NC sensitive tumor cells by /sup 125/I-laminin binding and laminin induced cell-cell aggregation. The finding that the addition of exogenous laminin inhibits NK/NC binding to sensitive tumor cells suggests laminin binding sites may serve as target antigens for NK cells. The present study extends earlier reports by analyzing a large panel of tumor cells for laminin binding capacity, laminin expression and sensitivity to NK/NC killing. The data indicate that all tumor cells which bind to NK/NC cells (8 lines tested) express laminin binding sites. All of these tumor cells were capable of competing for NK lysis of YAC-1 cells in cold target competition assays, and all bound enriched NK cells in direct single cell binding assays. In contrast, tumor cells expressing high levels of surface laminin (B16 melanomas, C57B1/6 fibrosarcomas, and RAS transfected 3T3 fibroblasts) but low levels of laminin binding capacity did not bind NK/NC cells and were resistant to lysis. These data support the hypothesis that expression of laminin/laminin binding sites may contribute to tumor cell sensitivity to NK/NC binding and/or killing.

  7. 5α-Reductase Inhibition Suppresses Testosterone-Induced Initial Regrowth of Regressed Xenograft Prostate Tumors in Animal Models

    PubMed Central

    Masoodi, Khalid Z.; Ramos Garcia, Raquel; Pascal, Laura E.; Wang, Yujuan; Ma, Hei M.; O'Malley, Katherine; Eisermann, Kurtis; Shevrin, Daniel H.; Nguyen, Holly M.; Vessella, Robert L.; Nelson, Joel B.; Parikh, Rahul A.

    2013-01-01

    Androgen deprivation therapy (ADT) is the standard treatment for patients with prostate-specific antigen progression after treatment for localized prostate cancer. An alternative to continuous ADT is intermittent ADT (IADT), which allows recovery of testosterone during off-cycles to stimulate regrowth and differentiation of the regressed prostate tumor. IADT offers patients a reduction in side effects associated with ADT, improved quality of life, and reduced cost with no difference in overall survival. Our previous studies showed that IADT coupled with 5α-reductase inhibitor (5ARI), which blocks testosterone conversion to DHT could prolong survival of animals bearing androgen-sensitive prostate tumors when off-cycle duration was fixed. To further investigate this clinically relevant observation, we measured the time course of testosterone-induced regrowth of regressed LuCaP35 and LNCaP xenograft tumors in the presence or absence of a 5ARI. 5α-Reductase inhibitors suppressed the initial regrowth of regressed prostate tumors. However, tumors resumed growth and were no longer responsive to 5α-reductase inhibition several days after testosterone replacement. This finding was substantiated by bromodeoxyuridine and Ki67 staining of LuCaP35 tumors, which showed inhibition of prostate tumor cell proliferation by 5ARI on day 2, but not day 14, after testosterone replacement. 5α-Reductase inhibitors also suppressed testosterone-stimulated proliferation of LNCaP cells precultured in androgen-free media, suggesting that blocking testosterone conversion to DHT can inhibit prostate tumor cell proliferation via an intracrine mechanism. These results suggest that short off-cycle coupled with 5α-reductase inhibition could maximize suppression of prostate tumor growth and, thus, improve potential survival benefit achieved in combination with IADT. PMID:23671262

  8. A Novel IL6 Antibody Sensitizes Multiple Tumor Types to Chemotherapy Including Trastuzumab-Resistant Tumors.

    PubMed

    Zhong, Haihong; Davis, April; Ouzounova, Maria; Carrasco, Rosa A; Chen, Cui; Breen, Shannon; Chang, Yong S; Huang, Jiaqi; Liu, Zheng; Yao, Yihong; Hurt, Elaine; Moisan, Jacques; Fung, Michael; Tice, David A; Clouthier, Shawn G; Xiao, Zhan; Wicha, Max S; Korkaya, Hasan; Hollingsworth, Robert E

    2016-01-15

    Elevated levels of the proinflammatory cytokine IL6 are associated with poor survival outcomes in many cancers. Antibodies targeting IL6 and its receptor have been developed for chronic inflammatory disease, but they have not yet been shown to clearly benefit cancer patients, possibly due to antibody potency or the settings in which they have been tested. In this study, we describe the development of a novel high-affinity anti-IL6 antibody, MEDI5117, which features an extended half-life and potent inhibitory effects on IL6 biologic activity. MEDI5117 inhibited IL6-mediated activation of STAT3, suppressing the growth of several tumor types driven by IL6 autocrine signaling. In the same models, MEDI5117 displayed superior preclinical activity relative to a previously developed anti-IL6 antibody. Consistent with roles for IL6 in promoting tumor angiogenesis, we found that MEDI5117 inhibited the growth of endothelial cells, which can produce IL6 and support tumorigenesis. Notably, in tumor xenograft assays in mice, we documented the ability of MEDI5117 to enhance the antitumor activities of chemotherapy or gefitinib in combination treatment regimens. MEDI5117 also displayed robust activity on its own against trastuzumab-resistant HER2(+) tumor cells by targeting the CD44(+)CD24(-) cancer stem cell population. Collectively, our findings extend the evidence of important pleiotropic roles of IL6 in tumorigenesis and drug resistance, and offer a preclinical proof of concept for the use of IL6 antibodies in combination regimens to heighten therapeutic responses and overcome drug resistance.

  9. Phosphatidylinositol 3-kinase inhibition broadly sensitizes glioblastoma cells to death receptor- and drug-induced apoptosis.

    PubMed

    Opel, Daniela; Westhoff, Mike-Andrew; Bender, Ariane; Braun, Veit; Debatin, Klaus-Michael; Fulda, Simone

    2008-08-01

    The aberrant activity of the phosphatidylinositol 3-kinase (PI3K) pathway has been reported to correlate with adverse clinical outcome in human glioblastoma in vivo. However, the question of how this survival network can be successfully targeted to restore the sensitivity of glioblastoma to apoptosis induction has not yet been answered. Here, we report that inhibition of PI3K by LY294002 broadly sensitizes wild-type and mutant PTEN glioblastoma cells to both death receptor- and chemotherapy-induced apoptosis, whereas mammalian target of rapamycin (mTOR) inhibition is not sufficient to restore apoptosis sensitivity. LY294002 significantly enhances apoptosis triggered by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), agonistic anti-CD95 antibodies, or several anticancer drugs (i.e., doxorubicin, etoposide, and vincristine) in a highly synergistic manner. In addition, LY294002 cooperates with TRAIL or doxorubicin to suppress colony formation, thus also showing a strong effect on long-term survival. Similarly, genetic knockdown of PI3K subunits p110alpha and/or p110beta by RNA interference (RNAi) primes glioblastoma cells for TRAIL- or doxorubicin-mediated apoptosis. In contrast to PI3K inhibition, pharmacologic or genetic blockade of mTOR by RAD001 (everolimus), rapamycin, or RNAi fails to enhance TRAIL- or doxorubicin-induced apoptosis. Analysis of apoptosis pathways reveals that PI3K inhibition acts in concert with TRAIL or doxorubicin to trigger mitochondrial membrane permeabilization, caspase activation, and caspase-dependent apoptosis, which are abolished by the caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. Most importantly, PI3K inhibition by LY294002 sensitizes primary cultured glioblastoma cells obtained from surgical specimens to TRAIL- or chemotherapy-induced cell death. By showing that PI3K inhibition broadly primes glioblastoma cells for apoptosis, our findings provide the rationale for using PI3K inhibitors in

  10. PTEN Regulates Glutamine Flux to Pyrimidine Synthesis and Sensitivity to Dihydroorotate Dehydrogenase Inhibition.

    PubMed

    Mathur, Deepti; Stratikopoulos, Elias; Ozturk, Sait; Steinbach, Nicole; Pegno, Sarah; Schoenfeld, Sarah; Yong, Raymund; Murty, Vundavalli V; Asara, John M; Cantley, Lewis C; Parsons, Ramon

    2017-04-01

    Metabolic changes induced by oncogenic drivers of cancer contribute to tumor growth and are attractive targets for cancer treatment. Here, we found that increased growth of PTEN-mutant cells was dependent on glutamine flux through the de novo pyrimidine synthesis pathway, which created sensitivity to the inhibition of dihydroorotate dehydrogenase, a rate-limiting enzyme for pyrimidine ring synthesis. S-phase PTEN-mutant cells showed increased numbers of replication forks, and inhibitors of dihydroorotate dehydrogenase led to chromosome breaks and cell death due to inadequate ATR activation and DNA damage at replication forks. Our findings indicate that enhanced glutamine flux generates vulnerability to dihydroorotate dehydrogenase inhibition, which then causes synthetic lethality in PTEN-deficient cells due to inherent defects in ATR activation. Inhibition of dihydroorotate dehydrogenase could thus be a promising therapy for patients with PTEN-mutant cancers.Significance: We have found a prospective targeted therapy for PTEN-deficient tumors, with efficacy in vitro and in vivo in tumors derived from different tissues. This is based upon the changes in glutamine metabolism, DNA replication, and DNA damage response which are consequences of inactivation of PTENCancer Discov; 7(4); 380-90. ©2017 AACR.See related article by Brown et al., p. 391This article is highlighted in the In This Issue feature, p. 339.

  11. Carbon monoxide expedites metabolic exhaustion to inhibit tumor growth.

    PubMed

    Wegiel, Barbara; Gallo, David; Csizmadia, Eva; Harris, Clair; Belcher, John; Vercellotti, Gregory M; Penacho, Nuno; Seth, Pankaj; Sukhatme, Vikas; Ahmed, Asif; Pandolfi, Pier Paolo; Helczynski, Leszek; Bjartell, Anders; Persson, Jenny Liao; Otterbein, Leo E

    2013-12-01

    One classical feature of cancer cells is their metabolic acquisition of a highly glycolytic phenotype. Carbon monoxide (CO), one of the products of the cytoprotective molecule heme oxygenase-1 (HO-1) in cancer cells, has been implicated in carcinogenesis and therapeutic resistance. However, the functional contributions of CO and HO-1 to these processes are poorly defined. In human prostate cancers, we found that HO-1 was nuclear localized in malignant cells, with low enzymatic activity in moderately differentiated tumors correlating with relatively worse clinical outcomes. Exposure to CO sensitized prostate cancer cells but not normal cells to chemotherapy, with growth arrest and apoptosis induced in vivo in part through mitotic catastrophe. CO targeted mitochondria activity in cancer cells as evidenced by higher oxygen consumption, free radical generation, and mitochondrial collapse. Collectively, our findings indicated that CO transiently induces an anti-Warburg effect by rapidly fueling cancer cell bioenergetics, ultimately resulting in metabolic exhaustion.

  12. CDC42 inhibition suppresses progression of incipient intestinal tumors

    PubMed Central

    Sakamori, Ryotaro; Yu, Shiyan; Zhang, Xiao; Hoffman, Andrew; Sun, Jiaxin; Das, Soumyashree; Vedula, Pavan; Li, Guangxun; Fu, Jiang; Walker, Francesca; Yang, Chung S.; Yi, Zheng; Hsu, Wei; Yu, Da-Hai; Shen, Lanlan; Rodriguez, Alexis J.; Taketo, Makoto M.; Bonder, Edward M.; Verzi, Michael P.; Gao, Nan

    2014-01-01

    Mutations in the APC or β-catenin genes are well established initiators of colorectal cancer (CRC), yet modifiers that facilitate the survival and progression of nascent tumor cells are not well defined. Using genetic and pharmacological approaches in mouse CRC and human CRC xenograft models, we show that incipient intestinal tumor cells activate CDC42, an APC-interacting small GTPase, as a crucial step in malignant progression. In the mouse, Cdc42 ablation attenuated the tumorigenicity of mutant intestinal cells carrying single APC or β-catenin mutations. Similarly, human CRC with relatively higher levels of CDC42 activity were particularly sensitive to CDC42 blockade. Mechanistic studies suggested that Cdc42 may be activated at different levels, including at the level of transcriptional activation of the stem-cell-enriched Rho family exchange factor Arhgef4. Our results suggest that early-stage mutant intestinal epithelial cells must recruit the pleiotropic functions of Cdc42 for malignant progression, suggesting its relevance as a biomarker and therapeutic target for selective CRC intervention. PMID:25113996

  13. Gracilaria edulis extract induces apoptosis and inhibits tumor in Ehrlich ascites tumor cells in vivo.

    PubMed

    Patra, Satyajit; Muthuraman, Meenakshi Sundaram

    2013-11-25

    Marine environment is inestimable for their chemical and biological diversity and therefore is an extraordinary resource for the discovery of new anticancer drugs. Recent development in elucidation of the mechanism and therapeutic action of natural products helped to evaluate for their potential activity. We evaluated Gracilaria edulis J. Ag (Brown algae), for its antitumor potential against the Ehrlich ascites tumor (EAT) in vivo and in vitro. Cytotoxicity evaluation of Ethanol Extract of Gracilaria edulis (EEGE) using EAT cells showed significant activity. In vitro studies indicated that EEGE cytotoxicity to EAT cells is mediated through its ability to produce reactive oxygen species (ROS) and therefore decreasing intracellular glutathione (GSH) levels may be attributed to oxidative stress. Apoptotic parameters including Annexin-V positive cells, increased levels of DNA fragmentation and increased caspase-2, caspase-3 and caspase-9 activities indicated the mechanism might be by inducing apoptosis. Intraperitoneally administration of EEGE to EAT-bearing mice helped to increase the lifespan of the animals significantly inhibited tumor growth and increased survival of mice. Extensive hematology, biochemistry and histopathological analysis of liver and kidney indicated that daily doses of EEGE up to 300 mg/kg for 35 days are well tolerated and did not cause hematotoxicity nor renal or hepatotoxicity. Comprehensive antitumor analysis in animal model and in Ehrlich Ascites Tumor cells was done including biochemical, and pathological evaluations indicate antitumor activity of the extract and non toxic in vivo. It was evident that the mechanism explains the apoptotic activity of the algae extract.

  14. Colchicine inhibits pressure-induced tumor cell implantation within surgical wounds and enhances tumor-free survival in mice

    PubMed Central

    Craig, David H.; Owen, Cheri R.; Conway, William C.; Walsh, Mary F.; Downey, Christina; Basson, Marc D.

    2008-01-01

    Iatrogenic tumor cell implantation within surgical wounds can compromise curative cancer surgery. Adhesion of cancer cells, in particular colon cancer cells, is stimulated by exposure to increased extracellular pressure through a cytoskeleton-dependent signaling mechanism requiring FAK, Src, Akt, and paxillin. Mechanical stimuli during tumor resection may therefore negatively impact patient outcome. We hypothesized that perioperative administration of colchicine, which prevents microtubule polymerization, could disrupt pressure-stimulated tumor cell adhesion to surgical wounds and enhance tumor-free survival. Ex vivo treatment of Co26 and Co51 colon cancer cells with colchicine inhibited pressure-stimulated cell adhesion to murine surgical wounds and blocked pressure-induced FAK and Akt phosphorylation. Surgical wound contamination with pressure-activated Co26 and Co51 cells significantly reduced tumor-free survival compared with contamination with tumor cells under ambient pressure. Mice treated with pressure-activated Co26 and Co51 cells from tumors preoperatively treated with colchicine in vivo displayed reduced surgical site implantation and significantly increased tumor-free survival compared with mice exposed to pressure-activated cells from tumors not pretreated with colchicine. Our data suggest that pressure activation of malignant cells promotes tumor development and impairs tumor-free survival and that perioperative colchicine administration or similar interventions may inhibit this effect. PMID:18704196

  15. A systemic administration of liposomal curcumin inhibits radiation pneumonitis and sensitizes lung carcinoma to radiation

    PubMed Central

    Shi, Hua-shan; Gao, Xiang; Li, Dan; Zhang, Qiong-wen; Wang, Yong-sheng; Zheng, Yu; Cai, Lu-Lu; Zhong, Ren-ming; Rui, Ao; Li, Zhi-yong; Zheng, Hao; Chen, Xian-cheng; Chen, Li-juan

    2012-01-01

    Radiation pneumonitis (RP) is an important dose-limiting toxicity during thoracic radiotherapy. Previous investigations have shown that curcumin is used for the treatment of inflammatory conditions and cancer, suggesting that curcumin may prevent RP and sensitize cancer cells to irradiation. However, the clinical advancement of curcumin is limited by its poor water solubility and low bioavailability after oral administration. Here, a water-soluble liposomal curcumin system was developed to investigate its prevention and sensitizing effects by an intravenous administration manner in mice models. The results showed that liposomal curcumin inhibited nuclear factor-κB pathway and downregulated inflammatory factors including tumor necrosis factor-α, interleukin (IL)-6, IL-8, and transforming growth factor-β induced by thoracic irradiation. Furthermore, the combined treatment with liposomal curcumin and radiotherapy increased intratumoral apoptosis and microvessel responses to irradiation in vivo. The significantly enhanced inhibition of tumor growth also was observed in a murine lung carcinoma (LL/2) model. There were no obvious toxicities observed in mice. The current results indicate that liposomal curcumin can effectively mitigate RP, reduce the fibrosis of lung, and sensitize LL/2 cells to irradiation. This study also suggests that the systemic administration of liposomal curcumin is safe and deserves to be investigated for further clinical application. PMID:22679371

  16. Inhibition of Skp2 sensitizes lung cancer cells to paclitaxel

    PubMed Central

    Huang, Tonghai; Yang, Lin; Wang, Guangsuo; Ding, Guanggui; Peng, Bin; Wen, Yuxin; Wang, Zheng

    2017-01-01

    S-phase kinase-associated protein 2 (Skp2) is an E3 ubiquitin ligase and plays an important role in the control of cell cycle progression. Skp2 is upregulated in several cancers, including lung cancers, but the role of Skp2 in the tumorigenesis and anticancer drug resistance in human lung cancer remains to be determined. We report here that Skp2 positively regulated mitotic arrest deficient 2 (MAD2) expression and that inhibition of Skp2 sensitizes human lung cancer cells to paclitaxel. Knockdown of Skp2 by small interfering RNA (siRNA) decreased Mad2 messenger RNA (mRNA) and protein levels in A549 and NCI-H1975 cells, accompanied with upregulation of p27 but decrease of the phosphorylation of retinoblastoma (Rb). In contrast, ectopic overexpression of Skp2 increased Mad2 mRNA and protein levels and phosphorylation of Rb, while it decreased p27. Pharmacological inhibition of CDK1/2 by flavopiridol or E2F1 with HLM006474 led to downregulation of Mad2 expression and prevented the increase of Mad2 expression by Skp2. Most importantly, pharmacological inhibition of Skp2 sensitized A549 and NCI-H1299 cells to paclitaxel. Our results demonstrated that SKP2 positively regulates the gene expression of MAD2 through p27-CDKs-E2F1 signaling pathway and that inhibition of Skp2 sensitizes A549 and NCI-H1299 cells to paclitaxel, suggesting that small molecule inhibitors of Skp2 are potential agents for the treatment of lung cancer with upregulation of Skp2. PMID:28176922

  17. Inhibition of Skp2 sensitizes lung cancer cells to paclitaxel.

    PubMed

    Huang, Tonghai; Yang, Lin; Wang, Guangsuo; Ding, Guanggui; Peng, Bin; Wen, Yuxin; Wang, Zheng

    2017-01-01

    S-phase kinase-associated protein 2 (Skp2) is an E3 ubiquitin ligase and plays an important role in the control of cell cycle progression. Skp2 is upregulated in several cancers, including lung cancers, but the role of Skp2 in the tumorigenesis and anticancer drug resistance in human lung cancer remains to be determined. We report here that Skp2 positively regulated mitotic arrest deficient 2 (MAD2) expression and that inhibition of Skp2 sensitizes human lung cancer cells to paclitaxel. Knockdown of Skp2 by small interfering RNA (siRNA) decreased Mad2 messenger RNA (mRNA) and protein levels in A549 and NCI-H1975 cells, accompanied with upregulation of p27 but decrease of the phosphorylation of retinoblastoma (Rb). In contrast, ectopic overexpression of Skp2 increased Mad2 mRNA and protein levels and phosphorylation of Rb, while it decreased p27. Pharmacological inhibition of CDK1/2 by flavopiridol or E2F1 with HLM006474 led to downregulation of Mad2 expression and prevented the increase of Mad2 expression by Skp2. Most importantly, pharmacological inhibition of Skp2 sensitized A549 and NCI-H1299 cells to paclitaxel. Our results demonstrated that SKP2 positively regulates the gene expression of MAD2 through p27-CDKs-E2F1 signaling pathway and that inhibition of Skp2 sensitizes A549 and NCI-H1299 cells to paclitaxel, suggesting that small molecule inhibitors of Skp2 are potential agents for the treatment of lung cancer with upregulation of Skp2.

  18. ROLES OF INHIBITION IN COMPLEX AUDITORY RESPONSES IN THE INFERIOR COLLICULUS: INHIBITED COMBINATION-SENSITIVE NEURONS

    PubMed Central

    Nataraj, Kiran; Wenstrup, Jeffrey J.

    2006-01-01

    We studied the functional properties and underlying neural mechanisms associated with inhibitory combination-sensitive neurons in the mustached bat’s inferior colliculus (IC). In these neurons, the excitatory response to best frequency tones was suppressed by lower frequency signals (usually in the range 12-30 kHz) in a time-dependant manner. Of 143 inhibitory units, the majority (71%) were type I, in which low frequency sounds evoked inhibition only. In the remainder, however, the low frequency inhibitory signal also evoked excitation. Of these, excitation preceded the inhibition in type E/I units (16%), while in type I/E units (13%) excitation followed the inhibition. Type E/I and I/E units were distinct in the tuning and threshold sensitivity of low frequency responses, while type I units overlapped the other types in these features. In 71 neurons, antagonists to receptors for glycine (strychnine, STRY) or γ-aminobutyric acid (GABA) (bicuculline, BIC) were applied micro-iontophoretically. These antagonists failed to eliminate combination-sensitive inhibition in 92% (STRY), 93% (BIC), and 87% (BIC+STRY) of the type I units tested. However, inhibition was reduced in many neurons. Results were similar for type E/I and I/E inhibitory neurons. The results indicate that there are distinct populations of combination-sensitive inhibited neurons in the IC, and that these populations are at least partly independent of glycine or GABAA receptors in the IC. We propose that these populations originate in different brainstem auditory nuclei, that they may be modified by interactions within the IC, and that they may perform different spectrotemporal analyses of vocal signals. PMID:16371455

  19. Sensitivity of tumor cells towards CIGB-300 anticancer peptide relies on its nucleolar localization.

    PubMed

    Perera, Yasser; Costales, Heydi C; Diaz, Yakelin; Reyes, Osvaldo; Farina, Hernan G; Mendez, Lissandra; Gómez, Roberto E; Acevedo, Boris E; Gomez, Daniel E; Alonso, Daniel F; Perea, Silvio E

    2012-04-01

    CIGB-300 is a novel anticancer peptide that impairs the casein kinase 2-mediated phosphorylation by direct binding to the conserved phosphoacceptor site on their substrates. Previous findings indicated that CIGB-300 inhibits tumor cell proliferation in vitro and induces tumor growth delay in vivo in cancer animal models. Interestingly, we had previously demonstrated that the putative oncogene B23/nucleophosmin (NPM) is the major intracellular target for CIGB-300 in a sensitive human lung cancer cell line. However, the ability of this peptide to target B23/NPM in cancer cells with differential CIGB-300 response phenotype remained to be determined. Interestingly, in this work, we evidenced that CIGB-300's antiproliferative activity on tumor cells strongly correlates with its nucleolar localization, the main subcellular localization of the previously identified B23/NPM target. Likewise, using CIGB-300 equipotent doses (concentration that inhibits 50% of proliferation), we demonstrated that this peptide interacts and inhibits B23/NPM phosphorylation in different cancer cell lines as evidenced by in vivo pull-down and metabolic labeling experiments. Moreover, such inhibition was followed by a fast apoptosis on CIGB-300-treated cells and also an impairment of cell cycle progression mainly after 5 h of treatment. Altogether, our data not only validates B23/NPM as a main target for CIGB-300 in cancer cells but also provides the first experimental clues to explain their differential antiproliferative response. Importantly, our findings suggest that further improvements to this cell penetrating peptide-based drug should entail its more efficient intracellular delivery at such subcellular localization.

  20. Clinically Relevant Doses of Candesartan Inhibit Growth of Prostate Tumor Xenografts In Vivo through Modulation of Tumor Angiogenesis

    PubMed Central

    Alhusban, Ahmed; Al-Azayzih, Ahmad; Goc, Anna; Gao, Fei; Fagan, Susan C.

    2014-01-01

    Angiotensin II receptor type 1 blockers (ARBs), widely used antihypertensive drugs, have also been investigated for their anticancer effects. The effect of ARBs on prostate cancer in experimental models compared with meta-analysis data from clinical trials is conflicting. Whereas this discrepancy might be due to the use of supratherapeutic doses of ARBs in cellular and animal models as compared with the clinical doses used in human trials, further investigation of the effects of clinical doses of ARBs on prostate cancer in experimental models is warranted. In the current study, we sought to determine the effects of candesartan on prostate cancer cellular function in vitro and tumor growth in vivo, and characterize the underlying mechanisms. Our analysis indicated that clinically relevant doses of candesartan significantly inhibited growth of PC3 cell tumor xenografts in mice. Interestingly, the same concentrations of candesartan actually promoted prostate cancer cellular function in vitro, through a modest but significant inhibition in apoptosis. Inhibition of tumor growth by candesartan was associated with a decrease in vascular endothelial growth factor (VEGF) expression in tumors and inhibition of tumor angiogenesis, but normalization of tumor vasculature. Although candesartan did not impair PC3 cell viability, it inhibited endothelial-barrier disruption by tumor-derived factors. Furthermore, candesartan significantly inhibited expression of VEGF in PC3 and DU145 cell lines independent of angiotensin II type 2 receptor, but potentially via angiotensin II type 1 receptor inhibition. Our findings clearly demonstrate the therapeutic potential of candesartan for prostate cancer and establish a link between ARBs, VEGF expression, and prostate tumor angiogenesis. PMID:24990940

  1. Targeting GIPC/synectin in pancreatic cancer inhibits tumor growth.

    PubMed

    Muders, Michael H; Vohra, Pawan K; Dutta, Shamit K; Wang, Enfeng; Ikeda, Yasuhiro; Wang, Ling; Udugamasooriya, D Gomika; Memic, Adnan; Rupasinghe, Chamila N; Rupashinghe, Chamila N; Baretton, Gustavo B; Aust, Daniela E; Langer, Silke; Datta, Kaustubh; Simons, Michael; Spaller, Mark R; Mukhopadhyay, Debabrata

    2009-06-15

    Various studies have shown the importance of the GAIP interacting protein, COOH-terminus (GIPC, also known as Synectin) as a central adaptor molecule in different signaling pathways and as an important mediator of receptor stability. GIPC/Synectin is associated with different growth-promoting receptors such as insulin-like growth factor receptor I (IGF-IR) and integrins. These interactions were mediated through its PDZ domain. GIPC/Synectin has been shown to be overexpressed in pancreatic and breast cancer. The goal of this study was to show the importance of GIPC/Synectin in pancreatic cancer growth and to evaluate a possible therapeutic strategy by using a GIPC-PDZ domain inhibitor. Furthermore, the effect of targeting GIPC on the IGF-I receptor as one of its associated receptors was tested. The in vivo effects of GIPC/Synectin knockdown were studied after lentiviral transduction of luciferase-expressing pancreatic cancer cells with short hairpin RNA against GIPC/Synectin. Additionally, a GIPC-PDZ--targeting peptide was designed. This peptide was tested for its influence on pancreatic cancer growth in vitro and in vivo. Knockdown of GIPC/Synectin led to a significant inhibition of pancreatic adenocarcinoma growth in an orthotopic mouse model. Additionally, a cell-permeable GIPC-PDZ inhibitor was able to block tumor growth significantly without showing toxicity in a mouse model. Targeting GIPC was accompanied by a significant reduction in IGF-IR expression in pancreatic cancer cells. Our findings show that targeting GIPC/Synectin and its PDZ domain inhibits pancreatic carcinoma growth and is a potential strategy for therapeutic intervention of pancreatic cancer.

  2. Inhibition of JNK Sensitizes Hypoxic Colon Cancer Cells to DNA-Damaging Agents.

    PubMed

    Vasilevskaya, Irina A; Selvakumaran, Muthu; Hierro, Lucia Cabal; Goldstein, Sara R; Winkler, Jeffrey D; O'Dwyer, Peter J

    2015-09-15

    We showed previously that in HT29 colon cancer cells, modulation of hypoxia-induced stress signaling affects oxaliplatin cytotoxicity. To further study the significance of hypoxia-induced signaling through JNK, we set out to investigate how modulation of kinase activities influences cellular responses of hypoxic colon cancer cells to cytotoxic drugs. In a panel of cell lines, we investigated effects of pharmacologic and molecular inhibition of JNK on sensitivity to oxaliplatin, SN-38, and 5-FU. Combination studies for the drugs and JNK inhibitor CC-401 were carried out in vitro and in vivo. Hypoxia-induced JNK activation was associated with resistance to oxaliplatin. CC-401 in combination with chemotherapy demonstrates synergism in colon cancer cell lines, although synergy is not always hypoxia specific. A more detailed analysis focused on HT29 and SW620 (responsive), and HCT116 (nonresponsive) lines. In HT29 and SW620 cells, CC-401 treatment results in greater DNA damage in the sensitive cells. In vivo, potentiation of bevacizumab, oxaliplatin, and the combination by JNK inhibition was confirmed in HT29-derived mouse xenografts, in which tumor growth delay was greater in the presence of CC-401. Finally, stable introduction of a dominant negative JNK1, but not JNK2, construct into HT29 cells rendered them more sensitive to oxaliplatin under hypoxia, suggesting differing input of JNK isoforms in cellular responses to chemotherapy. These findings demonstrate that signaling through JNK is a determinant of response to therapy in colon cancer models, and support the testing of JNK inhibition to sensitize colon tumors in the clinic. ©2015 American Association for Cancer Research.

  3. Inhibition of TRPV1 for the treatment of sensitive skin.

    PubMed

    Kueper, Thomas; Krohn, Michael; Haustedt, Lars Ole; Hatt, Hanns; Schmaus, Gerhard; Vielhaber, Gabriele

    2010-11-01

    During the past years, the topic sensitive skin became one of the most important fields in dermatology. The tremendous interest is based on several studies showing that about 50% of the population declares to have sensitive skin. The human thermoreceptor hTRPV1 was previously identified to contribute to this skin condition while facilitating neurogenic inflammation leading to hyperalgesia. Furthermore, skin sensitivity towards capsaicin, a natural activator of TRPV1, was shown to correlate with sensitive skin. In a screening campaign based on recombinant HEK293-cells stably transfected with hTRPV1, the selective antagonist trans-4-tert-butylcyclohexanol was identified. This antagonist is able to inhibit capsaicin-induced hTRPV1 activation with an IC(50) value of 34 ± 5 μm tested in HEK293-cells as well as in electrophysiological recordings performed in oocytes expressing hTRPV1. Strikingly, in a clinical study with 30 women using topical treatment with o/w emulsions containing 31.6 ppm capsaicin, we were able to show that 0.4% of this inhibitor significantly reduces capsaicin-induced burning (P < 0.0001) in vivo. Thus trans-4-tert-butylcyclohexanol has the potential as a novel bioactive for the treatment of sensitive skin.

  4. RG7212 anti-TWEAK mAb inhibits tumor growth through inhibition of tumor cell proliferation and survival signaling and by enhancing the host antitumor immune response.

    PubMed

    Yin, Xuefeng; Luistro, Leopoldo; Zhong, Hua; Smith, Melissa; Nevins, Tom; Schostack, Kathleen; Hilton, Holly; Lin, Tai-An; Truitt, Theresa; Biondi, Denise; Wang, Xiaoqian; Packman, Kathryn; Rosinski, Jim; Berkofsky-Fessler, Windy; Tang, Jian-Ping; Pant, Saumya; Geho, David; Vega-Harring, Suzana; Demario, Mark; Levitsky, Hy; Simcox, Mary

    2013-10-15

    To explore the role of TWEAK in tumor growth and antitumor immune response and the activity and mechanism of RG7212, an antagonistic anti-TWEAK antibody, in tumor models. TWEAK-induced signaling and gene expression were explored in tumor cell lines and inhibition of these effects and antitumor efficacy with RG7212 treatment was assessed in human tumor xenograft-, patient-derived xenograft, and syngeneic tumor models and phase I patients. Genetic features correlated with antitumor activity were characterized. In tumor cell lines, TWEAK induces proliferation, survival, and NF-κB signaling and gene expression that promote tumor growth and suppress antitumor immune responses. TWEAK-inducible CD274, CCL2, CXCL-10 and -11 modulate T-cell and monocyte recruitment, T-cell activation, and macrophage differentiation. These factors and TWEAK-induced signaling were decreased, and tumor, blood, and spleen immune cell composition was altered with RG7212 treatment in mice. RG7212 inhibits tumor growth in vivo in models with TWEAK receptor, Fn14, expression, and markers of pathway activation. In phase I testing, signs of tumor shrinkage and stable disease were observed without dose-limiting toxicity. In a patient with advanced, Fn14-positive, malignant melanoma with evidence of tumor regression, proliferation markers were dramatically reduced, tumor T-cell infiltration increased, and tumor macrophage content decreased. Antitumor activity, a lack of toxicity in humans and animals and no evidence of antagonism with standard of care or targeted agents in mice, suggests that RG7212 is a promising agent for use in combination therapies in patients with Fn14-positive tumors. ©2013 AACR.

  5. Escin, a pentacyclic triterpene, chemosensitizes human tumor cells through inhibition of nuclear factor-kappaB signaling pathway.

    PubMed

    Harikumar, Kuzhuvelil B; Sung, Bokyung; Pandey, Manoj K; Guha, Sushovan; Krishnan, Sunil; Aggarwal, Bharat B

    2010-05-01

    Agents that can enhance tumor cell apoptosis and inhibit invasion have potential for the treatment of cancer. Here, we report the identification of escin, a pentacyclic triterpenoid from horse chestnut that exhibits antitumor potential against leukemia and multiple myeloma. Whether examined by esterase staining, phosphatidyl-serine staining, DNA breakage, or caspase-mediated poly(ADP-ribose) polymerase cleavage, escin potentiated tumor necrosis factor (TNF)-induced apoptosis but inhibited tumor cell invasion. This correlated with the down-regulation of bcl-2, cellular inhibitor of apoptosis protein-2, cyclin D1, cyclooxygenase-2, intercellular adhesion molecule-1, matrix metalloproteinase-9, and vascular endothelial growth factor, which are all regulated by the activation of the transcription factor NF-kappaB. When examined by electrophoretic mobility shift assay, the triterpenoid suppressed nuclear factor-kappaB (NF-kappaB) activation induced by TNF and other inflammatory agents, and this correlated with the inhibition of IkappaBalpha phosphorylation and degradation, inhibition of IkappaB kinase complex (IKK) activation, suppression of p65 phosphorylation and nuclear translocation, and abrogation of NF-kappaB-dependent reporter activity. Overall, our results demonstrate that escin inhibits activation of NF-kappaB through inhibition of IKK, leading to down-regulation of NF-kappaB-regulated cell survival and metastatic gene products and thus resulting in sensitization of cells to cytokines and chemotherapeutic agents.

  6. Escin, a Pentacyclic Triterpene, Chemosensitizes Human Tumor Cells through Inhibition of Nuclear Factor-κB Signaling Pathway

    PubMed Central

    Harikumar, Kuzhuvelil B.; Sung, Bokyung; Pandey, Manoj K.; Guha, Sushovan; Krishnan, Sunil

    2010-01-01

    Agents that can enhance tumor cell apoptosis and inhibit invasion have potential for the treatment of cancer. Here, we report the identification of escin, a pentacyclic triterpenoid from horse chestnut that exhibits antitumor potential against leukemia and multiple myeloma. Whether examined by esterase staining, phosphatidyl-serine staining, DNA breakage, or caspase-mediated poly(ADP-ribose) polymerase cleavage, escin potentiated tumor necrosis factor (TNF)-induced apoptosis but inhibited tumor cell invasion. This correlated with the down-regulation of bcl-2, cellular inhibitor of apoptosis protein-2, cyclin D1, cyclooxygenase-2, intercellular adhesion molecule-1, matrix metalloproteinase-9, and vascular endothelial growth factor, which are all regulated by the activation of the transcription factor NF-κB. When examined by electrophoretic mobility shift assay, the triterpenoid suppressed nuclear factor-κB (NF-κB) activation induced by TNF and other inflammatory agents, and this correlated with the inhibition of IκBα phosphorylation and degradation, inhibition of IκB kinase complex (IKK) activation, suppression of p65 phosphorylation and nuclear translocation, and abrogation of NF-κB-dependent reporter activity. Overall, our results demonstrate that escin inhibits activation of NF-κB through inhibition of IKK, leading to down-regulation of NF-κB-regulated cell survival and metastatic gene products and thus resulting in sensitization of cells to cytokines and chemotherapeutic agents. PMID:20103608

  7. Zinc inhibits nuclear factor-kappa B activation and sensitizes prostate cancer cells to cytotoxic agents.

    PubMed

    Uzzo, Robert G; Leavis, Paul; Hatch, William; Gabai, Vladimir L; Dulin, Nickolai; Zvartau, Nadezhda; Kolenko, Vladimir M

    2002-11-01

    Prostate carcinogenesis involves transformation of zinc-accumulating normal epithelial cells to malignant cells, which do not accumulate zinc. In this study, we demonstrate by immunoblotting and immunohistochemistry that physiological levels of zinc inhibit activation of nuclear factor (NF)-kappa B transcription factor in PC-3 and DU-145 human prostate cancer cells, reduce expression of NF-kappa B-controlled antiapoptotic protein c-IAP2, and activate c-Jun NH(2)-terminal kinases. Preincubation of PC-3 cells with physiological concentrations of zinc sensitized tumor cells to tumor necrosis factor (TNF)-alpha, and paclitaxel mediated cell death as defined by terminal deoxynucleotidyl transferase-mediated nick end labeling assay. These results suggest one possible mechanism for the inhibitory effect of zinc on the development and progression of prostate malignancy and might have important consequences for the prevention and treatment of prostate cancer.

  8. Adenovirus replication as an in vitro probe for drug sensitivity in human tumors.

    PubMed

    Parsons, P G; Maynard, K R; Little, J H; McLeod, G R

    1986-04-01

    The feasibility of using adenovirus 5 as an in vitro probe for chemosensitivity in short-term cultures of human tumors was evaluated using human melanoma cell lines and primary cultures of melanoma biopsies. A convenient immunoperoxidase method was developed for quantitating viral replication 2 days after infection. Two different approaches were explored: the host cell reactivation assay (HCR) using drug-treated virus; and the viral capacity assay using drug-treated cells. The HCR assay detected sensitivity to 5-(3-methyl-1-triazeno)imidazole-4-carboxamide (MTIC) in Mer- (methyl excision repair deficient) cell lines as decreased ability of the cells to replicate MTIC-treated virus. This test should be applicable to DNA-damaging agents and repair-deficient tumors. Adenovirus replicated readily in nonproliferating primary cultures of melanoma biopsies; application of the HCR assays to this material identified one Mer- sample of 11 tested. Herpes viruses were not suitable for use in HCR because herpes simplex virus type 1 failed to distinguish Mer- from Mer+ melanoma cells; and nonproductive infection of MTIC-sensitive lymphoid cells with Epstein-Barr virus yielded an MTIC-resistant cell line. The second assay (viral capacity) involved determination of the inhibition of replication of untreated virus in treated cells. This approach correctly predicted sensitivity to hydroxyurea and deoxyadenosine in melanoma cell lines when compared with clonogenic survival assay. Viral capacity was also inhibited by cytosine arabinoside, fluorouracil, vincristine, adriamycin, 6-mercaptopurine and ionising radiation, and may therefore be useful for detecting sensitivity to a wide range of antitumor agents.

  9. Using polarization-sensitive optical coherence tomography to identify tumor stromal fibrosis and increase tumor biopsy yield (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hariri, Lida P.; Adams, David C.; Miller, Alyssa J.; Mino-Kenudson, Mari; Suter, Melissa J.

    2016-03-01

    Tissue biopsy is the principal method used to diagnose tumors in a variety of organ systems. It is essential to maximize tumor yield in biopsy specimens for both clinical diagnostic and research purposes. This is particularly important in tumors where additional tissue is needed for molecular analysis to identify patients who would benefit from mutation-specific targeted therapy, such as in lung carcinomas. Inadvertent sampling of fibrotic stroma within tumor nodules contaminates biopsies, decreases tumor yield, and can impede diagnosis. The ability to assess tumor composition and guide biopsy site selection in real time is likely to improve diagnostic yield. Polarization sensitive OCT (PS-OCT) measures birefringence in organized tissues, such as collagen, and could be used to distinguish tumor from fibrosis. In this study, PS-OCT was obtained in 65 lung nodule samples from surgical resection specimens containing varying ratios of tumor and fibrosis. PS-OCT was obtained with either a custom-built helical scanning catheter (0.8 or 1.6mm in diameter) or a dual-axis bench top scanner. Strong birefringence was observed in nodules containing dense fibrosis, with no birefringence in adjacent regions of tumor. Tumors admixed with early, loosely-organized collagen demonstrated mild-to-moderate birefringence, and tumors with little collagen content showed little to no birefringent signal. PS-OCT provides significant insights into tumor nodule composition, and has potential to differentiate tumor from stromal fibrosis during biopsy site selection to increase diagnostic tumor yield.

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

    PubMed

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

    2012-12-13

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

  11. Gracilaria edulis extract induces apoptosis and inhibits tumor in Ehrlich Ascites tumor cells in vivo

    PubMed Central

    2013-01-01

    Background Marine environment is inestimable for their chemical and biological diversity and therefore is an extraordinary resource for the discovery of new anticancer drugs. Recent development in elucidation of the mechanism and therapeutic action of natural products helped to evaluate for their potential activity. Methods We evaluated Gracilaria edulis J. Ag (Brown algae), for its antitumor potential against the Ehrlich ascites tumor (EAT) in vivo and in vitro. Cytotoxicity evaluation of Ethanol Extract of Gracilaria edulis (EEGE) using EAT cells showed significant activity. In vitro studies indicated that EEGE cytotoxicity to EAT cells is mediated through its ability to produce reactive oxygen species (ROS) and therefore decreasing intracellular glutathione (GSH) levels may be attributed to oxidative stress. Results Apoptotic parameters including Annexin-V positive cells, increased levels of DNA fragmentation and increased caspase-2, caspase-3 and caspase-9 activities indicated the mechanism might be by inducing apoptosis. Intraperitoneally administration of EEGE to EAT-bearing mice helped to increase the lifespan of the animals significantly inhibited tumor growth and increased survival of mice. Extensive hematology, biochemistry and histopathological analysis of liver and kidney indicated that daily doses of EEGE up to 300 mg/kg for 35 days are well tolerated and did not cause hematotoxicity nor renal or hepatotoxicity. Conclusion Comprehensive antitumor analysis in animal model and in Ehrlich Ascites Tumor cells was done including biochemical, and pathological evaluations indicate antitumor activity of the extract and non toxic in vivo. It was evident that the mechanism explains the apoptotic activity of the algae extract. PMID:24274337

  12. Inhibition of Glutathione Biosynthesis Sensitizes Plasmodium berghei to Antifolates

    PubMed Central

    Koonyosying, Pongpisid; Uthaipibull, Chairat; Kamchonwongpaisan, Sumalee

    2016-01-01

    Glutathione plays a central role in maintaining cellular redox homeostasis, and modulations to this status may affect malaria parasite sensitivity to certain types of antimalarials. In this study, we demonstrate that inhibition of glutathione biosynthesis in the Plasmodium berghei ANKA strain through disruption of the γ-glutamylcysteine synthetase (γ-GCS) gene, which encodes the first and rate-limiting enzyme in the glutathione biosynthetic pathway, significantly sensitizes parasites in vivo to pyrimethamine and sulfadoxine, but not to chloroquine, artesunate, or primaquine, compared with control parasites containing the same pyrimethamine-resistant marker cassette. Treatment of mice infected with an antifolate-resistant P. berghei control line with a γ-GCS inhibitor, buthionine sulfoximine, could partially abrogate pyrimethamine and sulfadoxine resistance. The role of glutathione in modulating the malaria parasite's response to antifolates suggests that development of specific inhibitors against Plasmodium γ-GCS may offer a new approach to counter Plasmodium antifolate resistance. PMID:26953195

  13. Enhancement of glioblastoma radioresponse by a selective COX-2 inhibitor celecoxib: Inhibition of tumor angiogenesis with extensive tumor necrosis

    SciTech Connect

    Kang, Khong Bee . E-mail: dmskkb@nccs.com.sg; Wang, Ting Ting; Woon, Chow Thai; Cheah, Elizabeth S.; Moore, Xiao Lei; Zhu Congju; Wong, Meng Cheong

    2007-03-01

    Purpose: Toward improved glioblastoma multiforme treatment, we determined whether celecoxib, a selective cyclooxygenase (COX)-2 inhibitor, could enhance glioblastoma radiosensitivity by inducing tumor necrosis and inhibiting tumor angiogenesis. Methods and Materials: U-87MG cells treated with celecoxib, irradiation, or both were assayed for clonogenic survival and angiogenic factor protein analysis (angiopoietin-1, angiopoietin-2, and vascular endothelial growth factor [VEGF]). In vivo, survival of mice intracranially implanted with U-87MG cells and treated with celecoxib and/or irradiation was monitored. Isolated tumors were assessed for tumor necrosis and tumor microvascular density by von Williebrand's factor (vWF) immunohistochemical staining. Results: Celecoxib (4 and 30 {mu}M; 24, 48, and 72 h) enhanced U-87MG cell radiosensitivity by significantly reducing clonogenic survival of irradiated cells. Angiopoietin-1 and VEGF proteins were decreased, whereas angiopoietin-2 expression increased after 72 h of celecoxib alone and when combined with irradiation. In vivo, median survival of control mice intracranially implanted with U-87MG cells was 18 days. Celecoxib (100 mg/kg/day, 2 weeks) significantly extended median survival of irradiated mice (24 Gy total) from 34 to 41 days, with extensive tumor necrosis [24.5 {+-} 8.6% of tumor region, compared with irradiation alone (2.7 {+-} 1.8%)]. Tumor microvascular density was significantly reduced in combined celecoxib and irradiated tumors (52.5 {+-} 2.9 microvessels per mm{sup 2} tumor region), compared with irradiated tumors alone (65.4 {+-} 4.0 microvessels per mm{sup 2}). Conclusion: Celecoxib significantly enhanced glioblastoma radiosensitivity, reduced clonogenic survival, and prolonged survival of glioblastoma-implanted mice by inhibition of tumor angiogenesis with extensive tumor necr0010os.

  14. Enalapril and ASS inhibit tumor growth in a transgenic mouse model of islet cell tumors.

    PubMed

    Fendrich, V; Lopez, C L; Manoharan, J; Maschuw, K; Wichmann, S; Baier, A; Holler, J P; Ramaswamy, A; Bartsch, D K; Waldmann, J

    2014-10-01

    Accumulating evidence suggests a role for angiotensin-converting enzymes involving the angiotensin II-receptor 1 (AT1-R) and the cyclooxygenase pathway in carcinogenesis. The effects of ASS and enalapril were assessed in vitro and in a transgenic mouse model of pancreatic neuroendocrine neoplasms (pNENs). The effects of enalapril and ASS on proliferation and expression of the AGTR1A and its target gene vascular endothelial growth factor (Vegfa) were assessed in the neuroendocrine cell line BON1. Rip1-Tag2 mice were treated daily with either 0.6 mg/kg bodyweight of enalapril i.p., 20 mg/kg bodyweight of ASS i.p., or a vehicle in a prevention (weeks 5-12) and a survival group (week 5 till death). Tumor surface, weight of pancreatic glands, immunostaining for AT1-R and nuclear factor kappa beta (NFKB), and mice survival were analyzed. In addition, sections from human specimens of 20 insulinomas, ten gastrinomas, and 12 non-functional pNENs were evaluated for AT1-R and NFKB (NFKB1) expression and grouped according to the current WHO classification. Proliferation was significantly inhibited by enalapril and ASS in BON1 cells, with the combination being the most effective. Treatment with enalapril and ASS led to significant downregulation of known target genes Vegf and Rela at RNA level. Tumor growth was significantly inhibited by enalapril and ASS in the prevention group displayed by a reduction of tumor size (84%/67%) and number (30%/45%). Furthermore, daily treatment with enalapril and ASS prolonged the overall median survival compared with vehicle-treated Rip1-Tag2 (107 days) mice by 9 and 17 days (P=0.016 and P=0.013). The AT1-R and the inflammatory transcription factor NFKB were abolished completely upon enalapril and ASS treatment. AT1-R and NFKB expressions were observed in 80% of human pNENs. Enalapril and ASS may provide an approach for chemoprevention and treatment of pNENs.

  15. A Versatile Imaging and Therapeutic Platform Based on Dual-Band Luminescent Lanthanide Nanoparticles toward Tumor Metastasis Inhibition.

    PubMed

    Li, Yang; Tang, Jinglong; Pan, Dong-Xu; Sun, Ling-Dong; Chen, Chunying; Liu, Ying; Wang, Ye-Fu; Shi, Shuo; Yan, Chun-Hua

    2016-02-23

    Upconversion (UC) luminescent lanthanide nanoparticles (LNPs) are expected to play an important role in imaging and photodynamic therapy (PDT) in vitro and in vivo. However, with the absorption of UC emissions by photosensitizers (PSs) to generate singlet oxygen ((1)O2) for PDT, the imaging signals from LNPs are significantly weakened. It is important to activate another imaging route to track the location of the LNPs during PDT process. In this work, Nd(3+)-sensitized LNPs with dual-band visible and near-infrared (NIR) emissions under single 808 nm excitation were reported to address this issue. The UC emissions in green could trigger covalently linked rose bengal (RB) molecules for efficient PDT, and NIR emissions deriving from Yb(3+) and magnetic resonance imaging (MRI) were used for imaging simultaneously. Notably, the designed therapeutic platform could further effectively avoid the overheating effect induced by the laser irradiation, due to the minimized absorption of biological media at around 808 nm. TdT-mediated dUTP nick end labeling (TUNEL) assay showed serious cell apoptosis in the tumor after PDT for 2 weeks, leading to an effective tumor inhibition rate of 67%. Benefit from the PDT, the tumor growth-induced liver and spleen burdens were largely attenuated, and the liver injury was also alleviated. More importantly, pulmonary and hepatic tumor metastases were significantly reduced after PDT. The Nd(3+)-sensitized LNPs provide a multifunctional nanoplatform for NIR light-assisted PDT with minimized heating effect and an effective inhibition of tumor growth and metastasis.

  16. Colon tumor cell growth-inhibitory activity of sulindac sulfide and other nonsteroidal anti-inflammatory drugs is associated with phosphodiesterase 5 inhibition.

    PubMed

    Tinsley, Heather N; Gary, Bernard D; Thaiparambil, Jose; Li, Nan; Lu, Wenyan; Li, Yonghe; Maxuitenko, Yulia Y; Keeton, Adam B; Piazza, Gary A

    2010-10-01

    Nonsteroidal anti-inflammatory drugs (NSAID) display promising antineoplastic activity, but toxicity resulting from cyclooxygenase (COX) inhibition limits their clinical use for chemoprevention. Studies suggest that the mechanism may be COX independent, although alternative targets have not been well defined. Here, we show that the NSAID sulindac sulfide (SS) inhibits cyclic guanosine 3',5'-monophosphate (cGMP) phosphodiesterase (PDE) activity in colon tumor cell lysates at concentrations that inhibit colon tumor cell growth in vitro and in vivo. A series of chemically diverse NSAIDs also inhibited cGMP hydrolysis at concentrations that correlate with their potency to inhibit colon tumor cell growth, whereas no correlation was observed with COX-2 inhibition. Consistent with its selectivity for inhibiting cGMP hydrolysis compared with cyclic AMP hydrolysis, SS inhibited the cGMP-specific PDE5 isozyme and increased cGMP levels in colon tumor cells. Of numerous PDE isozyme-specific inhibitors evaluated, only the PDE5-selective inhibitor MY5445 inhibited colon tumor cell growth. The effects of SS and MY5445 on cell growth were associated with inhibition of β-catenin-mediated transcriptional activity to suppress the synthesis of cyclin D and survivin, which regulate tumor cell proliferation and apoptosis, respectively. SS had minimal effects on cGMP PDE activity in normal colonocytes, which displayed reduced sensitivity to SS and did not express PDE5. PDE5 was found to be overexpressed in colon tumor cell lines as well as in colon adenomas and adenocarcinomas compared with normal colonic mucosa. These results suggest that PDE5 inhibition, cGMP elevation, and inhibition of β-catenin transcriptional activity may contribute to the chemopreventive properties of certain NSAIDs.

  17. Targeting GIPC/Synectin in Pancreatic Cancer Inhibits Tumor Growth

    PubMed Central

    Muders, Michael H.; Vohra, Pawan K.; Dutta, Shamit K; Wang, Enfeng; Ikeda, Yasuhiro; Wang, Ling; Udugamasooriya, D. Gomika; Memic, Adnan; Rupashinghe, Chamila N.; Baretton, Gustavo B.; Aust, Daniela E.; Langer, Silke; Datta, Kaustubh; Simons, Michael; Spaller, Mark R.; Mukhopadhyay, Debabrata

    2009-01-01

    Translational Relevance The five year survival rate in patients with ductal adenocarcinoma of the pancreas is less than 4%. Accordingly, new targets for the treatment of this deadly disease are urgently needed. In this study, we show that targeting GAIP interacting protein C-terminal (GIPC, also known as Synectin) and its PDZ-domain reduces pancreatic cancer growth significantly in vitro and in vivo. Additionally, the blockage of GIPC/Synectin was accompanied by a reduction of IGF-1R protein levels. In summary, the use of a GIPC-PDZ domain inhibitor may be a viable option in the treatment of pancreatic adenocarcinoma in future. Purpose Various studies have demonstrated the importance of GAIP interacting protein, C-terminus (GIPC, also known as Synectin) as a central adaptor molecule in different signaling pathways and as an important mediator of receptor stability. GIPC/Synectin is associated with different growth promoting receptors like IGF-1R and integrins. These interactions were mediated through its PDZ domain. GIPC/Synectin has been shown to be overexpressed in pancreatic and breast cancer. The goal of this study was to demonstrate the importance of GIPC/Synectin in pancreatic cancer growth and to evaluate a possible therapeutic strategy by using a GIPC-PDZ domain inhibitor. Furthermore, the effect of targeting GIPC on the IGF-1 receptor as one of its associated receptors was tested. Experimental Design In vivo effects of GIPC/Synectin knockdown were studied after lentiviral transduction of luciferase-expressing pancreatic cancer cells with shRNA against GIPC/Synectin. Additionally, a GIPC-PDZ-targeting peptide was designed. This peptide was tested for its influence on pancreatic cancer growth in vitro and in vivo. Results Knockdown of GIPC/Synectin led to a significant inhibition of pancreatic adenocarcinoma growth in an orthotopic mouse model. Additionally, a cell-permeable GIPC-PDZ inhibitor was able to block tumor growth significantly without showing

  18. Enhancing chemotherapeutic drug inhibition on tumor growth by ultrasound: an in vivo experiment.

    PubMed

    Zhao, Ying-Zheng; Lu, Cui-Tao; Zhou, Zhi-Cai; Jin, Zhuo; Zhang, Lu; Sun, Chang-Zheng; Xu, Yan-Yan; Gao, Hui-Sheng; Tian, Ji-Lai; Gao, Feng-Hou; Tang, Qin-Qin; Li, Wei; Xiang, Qi; Li, Xiao-Kun; Li, Wen-Feng

    2011-02-01

    An in vivo study on enhancing epirubicin hydrochloride (EPI) inhibition on tumor growth by ultrasound (US) was reported. Five-week-old male nude mice were used and HL-60 cells were s.c. (subcutaneous injection) inoculated in axilla of these mice. Six groups were designed and five consecutive treatments were applied to investigate the inhibition on tumor growth and body weight growth. US applied locally to the tumor resulted in a substantially increased drug uptake in tumor cells. The inhibition on tumor growth depended on the position of drug injection and phospholipid-based microbubble (PMB) application. Tumor growth rate under group 1 (PMB+US) was similar to that of blank control. The order of the inhibition on tumor volume growth was: group 4 (s.c. EPI+PMB+US) > group 5 intraperitoneal (i.p. EPI+PMB+US) > group 2 (i.p. EPI) > group 3 (s.c. EPI+US) > group 1 (PMB+US). Similar conclusion was obtained from experimental measurements of tumor weight change. The order of animal survival status for EPI administration groups was: group 4 > group 5 > group 2 > group 3. Chemotherapeutic drug inhibition on tumor growth could be enhanced by local US combined with PMB, which might provide a potential application for US-mediated chemotherapy.

  19. Diethyl pyrocarbonate inhibits rostral ventrolateral medullary H+ sensitivity.

    PubMed

    Nattie, E E

    1988-04-01

    Diethyl pyrocarbonate (DEPC), an acylating agent that reacts with imidazole-histidine in vitro, inhibits CO2 sensitivity when applied by pledget to the rostral chemosensitive area on the ventrolateral medullary (VLM) surface in glomectomized, chloralose-urethan-anesthetized cats. In this study similar application of DEPC inhibits the phrenic nerve response to CO2 expressed as a function of VLM [H+] measured by surface pH electrode. Attempts to evaluate direct chemoreceptor stimulation by HCL-soaked surface pledgets proved difficult, but rostral DEPC did inhibit the response to intravenous infusion of HCl. As previously reported, the CO2 and intravenous H+ responses are not a unique function of the VLM [H+]. DEPC had similar inhibitory effects on both the CO2 and the intravenous H+ responses, suggesting that the difference between them may reflect more the orientation or accessibility of the central chemoreceptor than a different mechanism for sensing CO2 vs. H+. DEPC did not alter the phrenic nerve response to hypoxia, indicating that DEPC effects on central chemoreception are not the result of a generalized inhibitory process. The results support the hypothesis that imidazolehistidine is involved at the rostral area with chemoreception of both CO2 and H+.

  20. Hyaluronic acid-bound letrozole nanoparticles restore sensitivity to letrozole-resistant xenograft tumors in mice.

    PubMed

    Nair, Hareesh B; Huffman, Steven; Veerapaneni, Poornachand; Kirma, Nameer B; Binkley, Peter; Perla, Rao P; Evans, Dean B; Tekmal, Rajeshwar R

    2011-05-01

    Letrozole is a potent aromatase inhibitor and superior to other defined selective estrogen receptor modulators such as tamoxifen in treating hormone-responsive postmenopausal breast cancer patients. Patients who receive this drug may become insensitive to the effects of estrogen deprivation induced by letrozole. Letrozole has known side effects on bone metabolism due to systemic ablation of estrogen production. The purpose of this study was to examine the therapeutic efficacy of hyaluronic acid-bound letrozole nanoparticles (HA-Letr-NPs) in restoring sensitivity to letrozole-resistant (LTLT-Ca) cells. To target letrozole to LTLT-Ca cells, hyaluronic acid-bound letrozole nanoparticles were prepared by nanoprecipitation using biodegradable PLGA-PEG co-polymer. Binding specificity of HA to CD44 on the cell surface was analyzed in vitro using FITC-CD44 Ab and CD44 siRNA by flow cytometry. Effects on in vitro cytotoxicity and aromatase enzymatic activity of HA-Letr-NPs were performed in MCF-7 breast cancer cells, MCF-7 cells over-expressing aromatase (MCF-7/Aro), and LTLT-Ca cells resistant to letrozole. Preclinical efficacy of HA-Letr-NPs was examined in mice using LTLT-Ca xenograft tumors. HA-Letr-NPs were restricted to a maximum size of 100 nm. The in vitro drug release assay showed that the highest released concentration of letrozole occurred after 23 hours at 37 degrees C in phosphate-buffered saline. HA-Letr-NPs on MCF-7/Aro and LTLT-Ca cells showed an IC50 of 2 microM and 5 microM, respectively. HA-Letr-NPs were more efficacious in inhibiting tumor growth, reducing in vitro cellular and in vivo tumor aromatase enzyme activity more than the corresponding Letr-NPs or letrozole. HA-Letr-NPs restored and maintained a prolonged sensitivity and targeted delivery of letrozole in letrozole-resistant tumors in vivo.

  1. Tumor Specific Gene Expression and Tumor Specific Vector Replication for Systemic Chemotherapy Sensitization Treatment of Breast Cancer

    DTIC Science & Technology

    2002-07-01

    directed at the use of the L-plastin tumor-specific transcriptional promoter to control the expression of a chemotherapy sensitization gene ( cytosine ... deaminase ) and a viral replication gene (ElA) so that any toxic effect is tumor specific. These vectors have been shown to suppress the growth of human

  2. 5α-Reductase inhibition coupled with short off cycles increases survival in the LNCaP xenograft prostate tumor model on intermittent androgen deprivation therapy.

    PubMed

    Pascal, Laura E; Masoodi, Khalid Z; O'Malley, Katherine J; Shevrin, Daniel; Gingrich, Jeffrey R; Parikh, Rahul A; Wang, Zhou

    2015-04-01

    Intermittent androgen deprivation therapy in patients with prostate specific antigen progression after localized prostate cancer treatment is an alternative to standard continuous androgen deprivation therapy. Intermittent androgen deprivation therapy allows for testosterone recovery during off cycles. This stimulates regrowth and differentiation of the regressed prostate tumor, lessens the side effects of continuous androgen deprivation therapy and potentially prolongs survival. Previously intermittent androgen deprivation therapy coupled with finasteride was shown to prolong survival in animals bearing androgen sensitive prostate tumors when the off cycle duration was not prolonged but rather fixed at 10 to 14 days. Regressed prostate tumor xenografts with testosterone replacement were initially responsive to 5α-reductase inhibition but growth resumed after several days. In shorter off cycles of testosterone recovery 5α-reductase inhibition might maximize tumor growth inhibition during intermittent androgen deprivation therapy and perhaps increase survival. We used the LNCaP xenograft tumor model to evaluate the effectiveness of short off cycles of 4 days coupled with 5α-reductase inhibition on survival and tumor regrowth while on intermittent androgen deprivation therapy. Dutasteride inhibited initial testosterone induced tumor regrowth off cycles 1 and 2, and significantly increased survival. These results further support the potential for intermittent androgen deprivation therapy combined with 5α-reductase inhibition to improve survival in patients with prostate cancer when off cycle duration is short or very short. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  3. 5α-reductase Inhibition Coupled with Short Off Cycles Increases Survival in the LNCaP Xenograft Prostate Tumor Model on Intermittent Androgen Deprivation Therapy

    PubMed Central

    Pascal, Laura E.; Masoodi, Khalid Z.; O’Malley, Katherine J.; Shevrin, Daniel; Gingrich, Jeffrey R.; Parikh, Rahul A.; Wang, Zhou

    2014-01-01

    Purpose Intermittent androgen deprivation therapy (IADT) for patients with PSA progression after treatment for localized prostate cancer is an alternative to the standard continuous ADT. IADT allows for the recovery of testosterone during off-cycles to stimulate regrowth and differentiation of the regressed prostate tumor in order to lessen the side effects of continuous ADT and potentially prolong survival. Previously, IADT coupled with finasteride was shown to prolong survival of animals bearing androgen-sensitive prostate tumors when off-cycle duration was not prolonged and fixed at 10–14 days. Regressed prostate tumor xenografts with testosterone replacement were initially responsive to 5α-reductase inhibition, but resumed growth after several days in the animal models. 5α-reductase inhibition in shorter off-cycles of testosterone recovery could maximize tumor growth inhibition during IADT and perhaps increase survival. Materials and Methods The LNCaP xenograft tumor model was utilized to evaluate the effectiveness of short off-cycles of 4 days coupled with 5α-reductase inhibition on IADT on survival and tumor regrowth. Results Dutasteride inhibited initial testosterone-induced tumor regrowth during both the first and second off-cycle and significantly increased survival. Conclusions These results further support the potential for IADT combined with 5α-reductase inhibition to improve survival in prostate cancer patients when off cycle durations are short or very short. PMID:25444984

  4. Piperlongumine inhibits lung tumor growth via inhibition of nuclear factor kappa B signaling pathway

    PubMed Central

    Zheng, Jie; Son, Dong Ju; Gu, Sun Mi; Woo, Ju Rang; Ham, Young Wan; Lee, Hee Pom; Kim, Wun Jae; Jung, Jae Kyung; Hong, Jin Tae

    2016-01-01

    Piperlongumine has anti-cancer activity in numerous cancer cell lines via various signaling pathways. But there has been no study regarding the mechanisms of PL on the lung cancer yet. Thus, we evaluated the anti-cancer effects and possible mechanisms of PL on non-small cell lung cancer (NSCLC) cells in vivo and in vitro. Our findings showed that PL induced apoptotic cell death and suppressed the DNA binding activity of NF-κB in a concentration dependent manner (0–15 μM) in NSCLC cells. Docking model and pull down assay showed that PL directly binds to the DNA binding site of nuclear factor-κB (NF-κB) p50 subunit, and surface plasmon resonance (SPR) analysis showed that PL binds to p50 concentration-dependently. Moreover, co-treatment of PL with NF-κB inhibitor phenylarsine oxide (0.1 μM) or p50 siRNA (100 nM) augmented PL-induced inhibitory effect on cell growth and activation of Fas and DR4. Notably, co-treatment of PL with p50 mutant plasmid (C62S) partially abolished PL-induced cell growth inhibition and decreased the enhanced expression of Fas and DR4. In xenograft mice model, PL (2.5–5 mg/kg) suppressed tumor growth of NSCLC dose-dependently. Therefore, these results indicated that PL could inhibit lung cancer cell growth via inhibition of NF-κB signaling pathway in vitro and in vivo. PMID:27198178

  5. Isolated tumoral pyruvate dehydrogenase can synthesize acetoin which inhibits pyruvate oxidation as well as other aldehydes.

    PubMed

    Baggetto, L G; Lehninger, A L

    1987-05-29

    Oxidation of 1 mM pyruvate by Ehrlich and AS30-D tumor mitochondria is inhibited by acetoin, an unusual and important metabolite of pyruvate utilization by cancer cells, by acetaldehyde, methylglyoxal and excess pyruvate. The respiratory inhibition is reversed by other substrates added to pyruvate and also by 0.5 mM ATP. Kinetic properties of pyruvate dehydrogenase complex isolated from these tumor mitochondria have been studied. This complex appears to be able to synthesize acetoin from acetaldehyde plus pyruvate and is competitively inhibited by acetoin. The role of a new regulatory pattern for tumoral pyruvate dehydrogenase is presented.

  6. Targeting distinct tumor-infiltrating myeloid cells by inhibiting CSF-1 receptor: combating tumor evasion of antiangiogenic therapy.

    PubMed

    Priceman, Saul J; Sung, James L; Shaposhnik, Zory; Burton, Jeremy B; Torres-Collado, Antoni X; Moughon, Diana L; Johnson, Mai; Lusis, Aldons J; Cohen, Donald A; Iruela-Arispe, M Luisa; Wu, Lily

    2010-02-18

    Tumor-infiltrating myeloid cells (TIMs) support tumor growth by promoting angiogenesis and suppressing antitumor immune responses. CSF-1 receptor (CSF1R) signaling is important for the recruitment of CD11b(+)F4/80(+) tumor-associated macrophages (TAMs) and contributes to myeloid cell-mediated angiogenesis. However, the impact of the CSF1R signaling pathway on other TIM subsets, including CD11b(+)Gr-1(+) myeloid-derived suppressor cells (MDSCs), is unknown. Tumor-infiltrating MDSCs have also been shown to contribute to tumor angiogenesis and have recently been implicated in tumor resistance to antiangiogenic therapy, yet their precise involvement in these processes is not well understood. Here, we use the selective pharmacologic inhibitor of CSF1R signaling, GW2580, to demonstrate that CSF-1 regulates the tumor recruitment of CD11b(+)Gr-1(lo)Ly6C(hi) mononuclear MDSCs. Targeting these TIM subsets inhibits tumor angiogenesis associated with reduced expression of proangiogenic and immunosuppressive genes. Combination therapy using GW2580 with an anti-VEGFR-2 antibody synergistically suppresses tumor growth and severely impairs tumor angiogenesis along with reverting at least one TIM-mediated antiangiogenic compensatory mechanism involving MMP-9. These data highlight the importance of CSF1R signaling in the recruitment and function of distinct TIM subsets, including MDSCs, and validate the benefits of targeting CSF1R signaling in combination with antiangiogenic drugs for the treatment of solid cancers.

  7. The HSP90 Inhibitor, AT13387, Is Effective against Imatinib-Sensitive and -Resistant Gastrointestinal Stromal Tumor Models

    PubMed Central

    Smyth, Tomoko; Van Looy, Thomas; Curry, Jayne E.; Rodriguez-Lopez, Ana M.; Wozniak, Agnieszka; Zhu, Meijun; Donsky, Rachel; Morgan, Jennifer G.; Mayeda, Mark; Fletcher, Jonathan A.; Schöffski, Patrick; Lyons, John; Thompson, Neil T.; Wallis, Nicola G.

    2013-01-01

    The majority of gastrointestinal stromal tumors (GIST) are characterized by activating mutations of KIT, an HSP90 client protein. Further secondary resistance mutations within KIT limit clinical responses to tyrosine kinase inhibitors, such as imatinib. The dependence of KIT and its mutated forms on HSP90 suggests that HSP90 inhibition might be a valuable treatment option for GIST, which would be equally effective on imatinib-sensitive and -resistant clones. We investigated the activity of AT13387, a potent HSP90 inhibitor currently being evaluated in clinical trials, in both in vitro and in vivo GIST models. AT13387 inhibited the proliferation of imatinib-sensitive (GIST882, GIST-T1) and -resistant (GIST430, GIST48) cell lines, including those resistant to the geldanamycin analogue HSP90 inhibitor, 17-AAG. Treatment with AT13387 resulted in depletion of HSP90 client proteins, KIT and AKT, along with their phospho-forms in imatinib-sensitive and -resistant cell lines, irrespective of KIT mutation. KIT signaling was ablated, whereas HSP70, a marker of HSP90 inhibition, was induced. In vivo, antitumor activity of AT13387 was showed in both the imatinib-sensitive, GIST-PSW, xenograft model and a newly characterized imatinib-resistant, GIST430, xenograft model. Induction of HSP70, depletion of phospho-KIT and inhibition of KIT signaling were seen in tumors from both models after treatment with AT13387. A combination of imatinib and AT13387 treatment in the imatinib-resistant GIST430 model significantly enhanced tumor growth inhibition over either of the monotherapies. Importantly, the combination of AT13387 and imatinib was well tolerated. These results suggest AT13387 is an excellent candidate for clinical testing in GIST in combination with imatinib. PMID:22714264

  8. Peperomin E reactivates silenced tumor suppressor genes in lung cancer cells by inhibition of DNA methyltransferase.

    PubMed

    Wang, Xin-Zhi; Cheng, Ying; Wang, Kui-Long; Liu, Rui; Yang, Xiao-Lin; Wen, Hong-Mei; Chai, Chuan; Liang, Jing-Yu; Wu, Hao

    2016-10-01

    Advanced lung cancer has poor prognosis owing to its low sensitivity to current chemotherapy agents. Therefore, discovery of new therapeutic agents is urgently needed. In this study, we investigated the antitumor effects of peperomin E, a secolignan isolated from Peperomia dindygulensis, a frequently used Chinese folk medicine for lung cancer treatment. The results indicate that peperomin E has antiproliferative effects, promoting apoptosis and cell cycle arrest in non-small-cell lung cancer (NSCLC) cell lines in a dose-dependent manner, while showing lower toxicity against normal human lung epidermal cells. Peperomin E inhibited tumor growth in A549 xenograft BALB/c nude mice without significant secondary adverse effects, indicating that it may be safely used to treat NSCLC. Furthermore, the mechanisms underlying the anticancer effects of peperomin E have been investigated. Using an in silico target fishing method, we observed that peperomin E directly interacts with the active domain of DNA methyltransferase 1 (DNMT1), potentially affecting its genome methylation activity. Subsequent experiments verified that peperomin E decreased DNMT1 activity and expression, thereby decreasing global methylation and reactivating the epigenetically silenced tumor suppressor genes including RASSF1A, APC, RUNX3, and p16INK4, which in turn activates their mediated pro-apoptotic and cell cycle regulatory signaling pathways in lung cancer cells. The observations herein report for the first time that peperomin E is a potential chemotherapeutic agent for NSCLC. The anticancer effects of peperomin E may be partly attributable to its ability to demethylate and reactivate methylation-silenced tumor suppressor genes through direct inhibition of the activity and expression of DNMT1.

  9. N-end rule pathway inhibition assists colon tumor regression via necroptosis

    PubMed Central

    Agarwalla, Pritha; Banerjee, Rajkumar

    2016-01-01

    Recent study has shown that N-end rule pathway, an ubiquitin dependent proteolytic system, counteracts cell death by degrading many antisurvival protein fragments like BCLxL, BRCA1, RIPK1, etc. Inhibition of the N-end rule pathway can lead to metabolic stabilization of proapoptotic protein fragments like RIPK1, thereby sensitizing cells to programmed cell death. Receptor interacting serine-threonine protein kinase-1 (RIPK1) is one of the upstream regulators of programmed necrosis known as necroptosis. Necroptosis is particularly gaining attention of cancer biologists as it provides an alternate therapeutic modality to kill cancer cells, which often evolve multiple strategies to circumvent growth inhibition by apoptosis. Utilizing the over expression of biotin receptor in cancer cells, herein, we report that coadministration of synthetic hetero-bivalent N-end rule inhibitor RFC11 and anticancer drug shikonin solubilized in a stable biotin receptor-targeted liposome exhibited significant synergistic antitumor effect in both subcutaneous and orthotopic mouse colon tumor model through induction of necroptosis with distinctive upregulation of RIPK1. Besides developing a newly targeted formulation for necroptosis induction, this report is the first in vivo evidence demonstrating that potent inhibition of N-end rule pathway can enhance therapeutic efficacy of conventional chemotherapeutics. PMID:27556106

  10. Transmembrane tumor necrosis factor-alpha sensitizes adipocytes to insulin.

    PubMed

    Zhou, Wenjing; Yang, Peng; Liu, Li; Zheng, Shan; Zeng, Qingling; Liang, Huifang; Zhu, Yazhen; Zhang, Zunyue; Wang, Jing; Yin, Bingjiao; Gong, Feili; Wu, Yiping; Li, Zhuoya

    2015-05-05

    Transmembrane TNF-α (tmTNF-α) acts both as a ligand, delivering 'forward signaling' via TNFR, and as a receptor, transducing 'reverse signaling'. The contradiction of available data regarding the effect of tmTNF-α on insulin resistance may be due to imbalance in both signals. Here, we demonstrated that high glucose-induced impairment of insulin-stimulated glucose uptake by 3T3-L1 adipocytes was concomitant with decreased tmTNF-α expression and increased soluble TNF-α (sTNF-α) secretion. However, when TACE was inhibited, preventing the conversion of tmTNF-α to sTNF-α, this insulin resistance was partially reversed, indicating a salutary role of tmTNF-α. Treatment of 3T3-L1 adipocytes with exogenous tmTNF-α promoted insulin-induced phosphorylation of IRS-1 and Akt, facilitated GLUT4 expression and membrane translocation, and increased glucose uptake while addition of sTNF-α resulted in the opposite effect. Furthermore, tmTNF-α downregulated the production of IL-6 and MCP-1 via NF-κB inactivation, as silencing of A20, an inhibitor for NF-κB, by siRNA, abolished this effect of tmTNF-α. However, tmTNF-α upregulated adiponectin expression through the PPAR-γ pathway, as inhibition of PPAR-γ by GW9662 abrogated both tmTNF-α-induced adiponectin transcription and glucose uptake. Our data suggest that tmTNF-α functions as an insulin sensitizer via forward signaling. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  11. TGFβ1 Inhibition Increases the Radiosensitivity of Breast Cancer Cells In Vitro and Promotes Tumor Control by Radiation In Vivo

    PubMed Central

    Bouquet, Fanny; Pal, Anupama; Pilones, Karsten A.; Demaria, Sandra; Hann, Byron; Akhurst, Rosemary J.; Babb, Jim S.; Lonning, Scott M.; DeWyngaert, J. Keith; Formenti, Silvia C.; Barcellos-Hoff, Mary Helen

    2013-01-01

    Purpose To determine whether inhibition of TGFβ signaling prior to irradiation sensitizes human and murine cancer cells in vitro and in vivo. Experimental Design TGFβ-mediated growth and Smad phosphorylation of MCF7, Hs578T, MDA-MB-231, and T47D human breast cancer cell lines were examined and correlated with clonogenic survival following graded radiation doses with and without pretreatment with LY364947, a small molecule inhibitor of the TGFβ type I receptor kinase. The DNA damage response was assessed in irradiated MDA-MB-231 cells pretreated with LY364947 in vitro and LY2109761, a pharmacokinetically stable inhibitor of TGFβ signaling, in vivo. The in vitro response of a syngeneic murine tumor, 4T1, was tested using a TGFβ neutralizing antibody, 1D11, with single or fractionated radiation doses in vivo. Results Human breast cancer cell lines pretreated with TGFβ small molecule inhibitor were radio-sensitized, irrespective of sensitivity to TGFβ growth inhibition. Consistent with increased clonogenic cell death, radiation-induced phosphorylation of H2AX and p53 was significantly reduced in MDA-MB-231 triple-negative breast cancer cells when pretreated in vitro or in vivo with a TGFfS type I receptor kinase inhibitor. Moreover, TGFβ neutralizing antibodies increased radiation sensitivity, blocked γH2AX foci formation, and significantly increased tumor growth delay in 4T1 murine mammary tumors in response to single and fractionated radiation exposures. Conclusion These results show that TGFβ inhibition prior to radiation attenuated DNA damage responses, increased clonogenic cell death, and promoted tumor growth delay, and thus may be an effective adjunct in cancer radiotherapy. PMID:22028490

  12. Phloroglucinol Inhibits the Bioactivities of Endothelial Progenitor Cells and Suppresses Tumor Angiogenesis in LLC-Tumor-Bearing Mice

    PubMed Central

    Kwon, Yi-Hong; Jung, Seok-Yun; Kim, Jae-Won; Lee, Sang-Hun; Lee, Jun-Hee; Lee, Boo-Yong; Kwon, Sang-Mo

    2012-01-01

    Background There is increasing evidence that phloroglucinol, a compound from Ecklonia cava, induces the apoptosis of cancer cells, eventually suppressing tumor angiogenesis. Methodology/Principal Findings This is the first report on phloroglucinol's ability to potentially inhibit the functional bioactivities of endothelial progenitor cells (EPCs) and thereby attenuate tumor growth and angiogenesis in the Lewis lung carcinoma (LLC)-tumor-bearing mouse model. Although Phloroglucinol did not affect their cell toxicity, it specifically inhibited vascular endothelial growth factor (VEGF) dependent migration and capillary-like tube formation of EPCs. Our matrigel plug assay clearly indicated that orally injected phloroglucinol effectively disrupts VEGF-induced neovessel formation. Moreover, we demonstrated that when phloroglucinol is orally administered, it significantly inhibits tumor growth and angiogenesis as well as CD45−/CD34+ progenitor mobilization into peripheral blood in vivo in the LLC-tumor-bearing mouse model. Conclusions/Significance These results suggest a novel role for phloroglucinol: Phloroglucinol might be a modulator of circulating EPC bioactivities, eventually suppressing tumorigenesis. Therefore, phloroglucinol might be a candidate compound for biosafe drugs that target tumor angiogenesis. PMID:22496756

  13. Targeted Proapoptotic Peptides Depleting Adipose Stromal Cells Inhibit Tumor Growth

    PubMed Central

    Daquinag, Alexes C; Tseng, Chieh; Zhang, Yan; Amaya-Manzanares, Felipe; Florez, Fernando; Dadbin, Ali; Zhang, Tao; Kolonin, Mikhail G

    2016-01-01

    Progression of many cancers is associated with tumor infiltration by mesenchymal stromal cells (MSC). Adipose stromal cells (ASC) are MSC that serve as adipocyte progenitors and endothelium-supporting cells in white adipose tissue (WAT). Clinical and animal model studies indicate that ASC mobilized from WAT are recruited by tumors. Direct evidence for ASC function in tumor microenvironment has been lacking due to unavailability of approaches to specifically inactivate these cells. Here, we investigate the effects of a proteolysis-resistant targeted hunter-killer peptide D-WAT composed of a cyclic domain CSWKYWFGEC homing to ASC and of a proapoptotic domain KLAKLAK2. Using mouse bone marrow transplantation models, we show that D-WAT treatment specifically depletes tumor stromal and perivascular cells without directly killing malignant cells or tumor-infiltrating leukocytes. In several mouse carcinoma models, targeted ASC cytoablation reduced tumor vascularity and cell proliferation resulting in hemorrhaging, necrosis, and suppressed tumor growth. We also validated a D-WAT derivative with a proapoptotic domain KFAKFAK2 that was found to have an improved cytoablative activity. Our results for the first time demonstrate that ASC, recruited as a component of tumor microenvironment, support cancer progression. We propose that drugs targeting ASC can be developed as a combination therapy complementing conventional cancer treatments. PMID:26316391

  14. Neutral pH hydrogen-enriched electrolyzed water achieves tumor-preferential clonal growth inhibition over normal cells and tumor invasion inhibition concurrently with intracellular oxidant repression.

    PubMed

    Saitoh, Yasukazu; Okayasu, Hajime; Xiao, Li; Harata, Yoshikazu; Miwa, Nobuhiko

    2008-01-01

    The properties and effects of neutral pH hydrogen-enriched electrolyzed water (NHE water) on tumor cells were examined. NHE water diminished hydroxyl radicals as demonstrated by ESR in a cell-free system. Human tongue carcinoma cells HSC-4 were inhibited for either colony formation efficiencies or colony sizes by NHE water without significant inhibition to normal human tongue epithelial-like cells DOK. Furthermore, NHE water caused growth inhibition, cell degeneration, and inhibition of invasion through the reconstituted basement membrane to human fibrosarcoma cells HT-1080. Intracellular oxidants such as hydroperoxides and hydrogen peroxides were scavenged in HSC-4 or HT-1080 cells by NHE water. In the human oral cavity, a dissolved hydrogen concentrations (DH) of NHE water was drastically declined from 1.1 to 0.5 ppm, but settled to 0.3-0.4 ppm until 180 s, upon static holding without gargling. Thus, NHE water was shown to achieve tumor-preferential growth inhibition and tumor invasion together with scavenging of intracellular oxidants, and is expected as a preventive material against tumor progression and invasion.

  15. Zyflamend Suppresses Growth and Sensitizes Human Pancreatic Tumors to Gemcitabine in an Orthotopic Mouse Model Through Modulation of Multiple Targets

    PubMed Central

    Kunnumakkara, Ajaikumar B.; Sung, Bokyung; Ravindran, Jayaraj; Diagaradjane, Parmeswaran; Deorukhkar, Amit; Dey, Sanjit; Koca, Cemile; Tong, Zhimin; Gelovani, Juri G.; Guha, Sushovan; Krishnan, Sunil; Aggarwal, Bharat B.

    2011-01-01

    Agents that can potentiate the efficacy of standard chemotherapy against pancreatic cancer are of great interest. Because of their low cost and safety, patients commonly use a variety of dietary supplements, although evidence of their efficacy is often lacking. One such commonly used food supplement, Zyflamend, is a polyherbal preparation with potent anti-inflammatory activities, and preclinical efficacy against prostate and oral cancer. Whether Zyflamend has any efficacy against human pancreatic cancer alone or in combination with gemcitibine, a commonly used agent, was examined in cell cultures and in an orthotopic mouse model. In vitro, Zyflamend inhibited the proliferation of pancreatic cancer cell lines regardless of p53 status and also enhanced gemcitabine-induced apoptosis. This finding correlated with inhibition of NF-κB activation by Zyflamend and suppression of cyclin D1, c-myc, COX-2, Bcl-2, IAP, survivin, VEGF, ICAM-1, and CXCR4. In nude mice, oral administration of Zyflamend alone significantly inhibited the growth of orthotopically transplanted human pancreatic tumors, and when combined with gemcitabine, further enhanced the antitumor effects. Immunohistochemical and Western blot analyses of tumor tissue showed that the suppression of pancreatic cancer growth correlated with inhibition of proliferation index marker (Ki-67), COX-2, MMP-9, NF-κB, and VEGF. Overall, these results suggest that the concentrated multiherb product Zyflamend alone can inhibit the growth of human pancreatic tumors and, in addition, can sensitize pancreatic cancers to gemcitabine through the suppression of multiple targets linked to tumorigenesis. PMID:21935918

  16. Tamoxifen inhibits malignant peripheral nerve sheath tumor growth in an estrogen receptor–independent manner

    PubMed Central

    Byer, Stephanie J.; Eckert, Jenell M.; Brossier, Nicole M.; Clodfelder-Miller, Buffie J.; Turk, Amy N.; Carroll, Andrew J.; Kappes, John C.; Zinn, Kurt R.; Prasain, Jeevan K.; Carroll, Steven L.

    2011-01-01

    Few therapeutic options are available for malignant peripheral nerve sheath tumors (MPNSTs), the most common malignancy associated with neurofibromatosis type 1 (NF1). Guided by clinical observations suggesting that some NF1-associated nerve sheath tumors are hormonally responsive, we hypothesized that the selective estrogen receptor (ER) modulator tamoxifen would inhibit MPNST tumorigenesis in vitro and in vivo. To test this hypothesis, we examined tamoxifen effects on MPNST cell proliferation and survival, MPNST xenograft growth, and the mechanism by which tamoxifen impeded these processes. We found that 1–5 μM 4-hydroxy-tamoxifen induced MPNST cell death, whereas 0.01–0.1 μM 4-hydroxy-tamoxifen inhibited mitogenesis. Dermal and plexiform neurofibromas, MPNSTs, and MPNST cell lines expressed ERβ and G-protein-coupled ER-1 (GPER); MPNSTs also expressed estrogen biosynthetic enzymes. However, MPNST cells did not secrete 17β-estradiol, exogenous 17β-estradiol did not stimulate mitogenesis or rescue 4-hydroxy-tamoxifen effects on MPNST cells, and the steroidal antiestrogen ICI-182,780 did not mimic tamoxifen effects on MPNST cells. Further, ablation of ERβ and GPER had no effect on MPNST proliferation, survival, or tamoxifen sensitivity, indicating that tamoxifen acts via an ER-independent mechanism. Consistent with this hypothesis, inhibitors of calmodulin (trifluoperazine, W-7), another known tamoxifen target, recapitulated 4-hydroxy-tamoxifen effects on MPNST cells. Tamoxifen was also effective in vivo, demonstrating potent antitumor activity in mice orthotopically xenografted with human MPNST cells. We conclude that 4-hydroxy-tamoxifen inhibits MPNST cell proliferation and survival via an ER-independent mechanism. The in vivo effectiveness of tamoxifen provides a rationale for clinical trials in cases of MPNSTs. PMID:21075781

  17. NIR-Laser-Controlled Drug Release from DOX/IR-780-Loaded Temperature-Sensitive-Liposomes for Chemo-Photothermal Synergistic Tumor Therapy

    PubMed Central

    Yan, Fei; Duan, Wanlu; Li, Yekuo; Wu, Hao; Zhou, Yuli; Pan, Min; Liu, Hongmei; Liu, Xin; Zheng, Hairong

    2016-01-01

    NIR laser-induced photothermal therapy (PTT) through near-infrared agents has demonstrated the great potential in solid tumor ablation. However, the nonuniform heat distribution over tumors from PTT makes it insufficient to kill all tumor cells, resulting in tumor recurrence and inferior outcomes. To improve the tumor treatment efficacy, it is highly desirable to develop the combinational treatment of PTT with other modalities, especially with chemotherapeutic agents. Here we report a smart DOX/IR-780-loaded temperature-sensitive-liposome (DITSL) which can achieve NIR-laser-controlled drug release for chemo-photothermal synergistic tumor therapy. In this system, the liposoluble IR-780 was incorporated into the temperature-sensitive lipid bilayer and the soluble chemotherapeutic doxorubicin (DOX) was encapsulated in the hydrophilic core. The resulting DITSL is proved to be physiologically stable and can provide a fast and laser irradiation-controllable DOX release in the PBS and cellular conditions. We further employed this nanoparticle for tumor treatment, demonstrating significantly higher tumor inhibition efficacy than that of DOX-loaded temperature-sensitive-liposome (DTSL) or IR780-loaded temperature-sensitive-liposome (ITSL) in the in vitro cells and in vivo animals. Histological analysis further revealed much more apoptotic cells, confirming the advantageous anti-tumor effect of DITSL over DTSL or ITSL. Our study provides a promising strategy to realize chemo-photothermal synergistic combination therapy for breast tumors. PMID:27877239

  18. Devazepide, a nonpeptide antagonist of CCK receptors, induces apoptosis and inhibits Ewing tumor growth.

    PubMed

    Carrillo, Jaime; Agra, Noelia; Fernández, Noemí; Pestaña, Angel; Alonso, Javier

    2009-08-01

    The Ewing family of tumors is a group of highly malignant tumors that mainly arise in bone and most often affect children and young adults in the first two decades of life. Despite the use of multimodal therapy, the long-term disease-free survival rate of patients with Ewing tumors is still disappointingly low, making the discovery of innovative therapeutic strategies all the more necessary. We have recently shown that cholecystokinin (CCK), a neuroendocrine peptide, involved in many biological functions, including cell growth and proliferation, is a relevant target of the EWS/FLI1 oncoprotein characteristic of Ewing tumors. CCK silencing inhibits cell proliferation and tumor growth in vivo, suggesting that CCK acts as an autocrine growth factor for Ewing cells. Here, we analyzed the impact of two CCK receptor antagonists, devazepide (a CCK1-R antagonist) and L365 260 (a CCK2-R antagonist), on the growth of Ewing tumor cells. Devazepide (10 micromol/l) inhibited cell growth of four different Ewing tumor cells in vitro (range 85-88%), whereas the effect of the CCK2-R antagonist on cell growth was negligible. In a mouse tumor xenograft model, devazepide reduced tumor growth by 40%. Flow cytometry experiments showed that devazepide, but not L365 260, induced apoptosis of Ewing tumor cells. In summary, devazepide induces cell death of Ewing tumor cells, suggesting that it could represent a new therapeutic approach in the management of Ewing's tumor patients.

  19. Halofuginone inhibits angiogenesis and growth in implanted metastatic rat brain tumor model--an MRI study.

    PubMed

    Abramovitch, Rinat; Itzik, Anna; Harel, Hila; Nagler, Arnon; Vlodavsky, Israel; Siegal, Tali

    2004-01-01

    Tumor growth and metastasis depend on angiogenesis; therefore, efforts are made to develop specific angiogenic inhibitors. Halofuginone (HF) is a potent inhibitor of collagen type alpha1(I). In solid tumor models, HF has a potent antitumor and antiangiogenic effect in vivo, but its effect on brain tumors has not yet been evaluated. By employing magnetic resonance imaging (MRI), we monitored the effect of HF on tumor progression and vascularization by utilizing an implanted malignant fibrous histiocytoma metastatic rat brain tumor model. Here we demonstrate that treatment with HF effectively and dose-dependently reduced tumor growth and angiogenesis. On day 13, HF-treated tumors were fivefold smaller than control (P < .001). Treatment with HF significantly prolonged survival of treated animals (142%; P = .001). In HF-treated rats, tumor vascularization was inhibited by 30% on day 13 and by 37% on day 19 (P < .05). Additionally, HF treatment inhibited vessel maturation (P = .03). Finally, in HF-treated rats, we noticed the appearance of a few clusters of satellite tumors, which were distinct from the primary tumor and usually contained vessel cores. This phenomenon was relatively moderate when compared to previous reports of other antiangiogenic agents used to treat brain tumors. We therefore conclude that HF is effective for treatment of metastatic brain tumors.

  20. Ascitic and solid Ehrlich tumor inhibition by Chenopodium ambrosioides L. treatment.

    PubMed

    Nascimento, Flávia R F; Cruz, Gustavo V B; Pereira, Paulo Vitor S; Maciel, Márcia C G; Silva, Lucilene A; Azevedo, Ana Paula S; Barroqueiro, Elizabeth S B; Guerra, Rosane N M

    2006-04-25

    The leaves of Chenopodium ambrosioides L. [Chenopodiaceae] ('mastruz') have been indicated for the treatment of several diseases, among which the cancer. There are no results focusing the effect of C. ambrosioides treatment on tumor development in vivo. The aim of this study was to investigate the effect of treatment with C. ambrosioides on Ehrlich tumor development. Swiss mice were treated by intraperitoneal route (i.p.) with hydroalcoholic extract from leaves of C. ambrosioides (5 mg/kg) or with PBS (control group) 48 h before or 48 h later the Ehrlich tumor implantation. The tumor cells were implanted on the left footpad (solid tumor) or in the peritoneal cavity (ascitic tumor). To determine the solid tumor growth, footpad was measured each 2 days until the fourteenth day, when the feet were weighed. Ascitic tumor development was evaluated after 8 days of tumor implantation by quantification of the ascitic fluid volume and tumor cell number. The i.p. administration of C. ambrosioides extract before or after the tumor implantation significantly inhibited the solid and ascitic Ehrlich tumor forms. This inhibition was observed in ascitic tumor cell number, in the ascitic volume, in the tumor-bearing foot size and foot weight when compared to control mice. The treatments also increased the survival of tumor-bearing mice. In conclusion, C. ambrosioides has a potent anti-tumoral effect which was evident with a small dose and even when the treatment was given two days after the tumor implantation. This effect is probably related with anti-oxidant properties of C. ambrosioides.

  1. RAS/MAPK Activation Drives Resistance to Smo Inhibition, Metastasis, and Tumor Evolution in Shh Pathway-Dependent Tumors.

    PubMed

    Zhao, Xuesong; Ponomaryov, Tatyana; Ornell, Kimberly J; Zhou, Pengcheng; Dabral, Sukriti K; Pak, Ekaterina; Li, Wei; Atwood, Scott X; Whitson, Ramon J; Chang, Anne Lynn S; Li, Jiang; Oro, Anthony E; Chan, Jennifer A; Kelleher, Joseph F; Segal, Rosalind A

    2015-09-01

    Aberrant Shh signaling promotes tumor growth in diverse cancers. The importance of Shh signaling is particularly evident in medulloblastoma and basal cell carcinoma (BCC), where inhibitors targeting the Shh pathway component Smoothened (Smo) show great therapeutic promise. However, the emergence of drug resistance limits long-term efficacy, and the mechanisms of resistance remain poorly understood. Using new medulloblastoma models, we identify two distinct paradigms of resistance to Smo inhibition. Sufu mutations lead to maintenance of the Shh pathway in the presence of Smo inhibitors. Alternatively activation of the RAS-MAPK pathway circumvents Shh pathway dependency, drives tumor growth, and enhances metastatic behavior. Strikingly, in BCC patients treated with Smo inhibitor, squamous cell cancers with RAS/MAPK activation emerged from the antecedent BCC tumors. Together, these findings reveal a critical role of the RAS-MAPK pathway in drug resistance and tumor evolution of Shh pathway-dependent tumors.

  2. RAS/MAPK activation drives resistance to Smo inhibition, metastasis and tumor evolution in Shh pathway-dependent tumors

    PubMed Central

    Zhao, Xuesong; Ponomaryov, Tatyana; Ornell, Kimberly J.; Zhou, Pengcheng; Dabral, Sukriti K.; Pak, Ekaterina; Li, Wei; Atwood, Scott X.; Whitson, Ramon J.; Chang, Anne Lynn S.; Li, Jiang; Oro, Anthony E.; Chan, Jennifer A.; Kelleher, Joseph F.; Segal, Rosalind A.

    2015-01-01

    Aberrant Shh signaling promotes tumor growth in diverse cancers. The importance of Shh signaling is particularly evident in medulloblastoma and basal cell carcinoma (BCC), where inhibitors targeting the Shh pathway component Smoothened (Smo) show great therapeutic promise. However, the emergence of drug resistance limits long-term efficacy and the mechanisms of resistance remain poorly understood. Using new medulloblastoma models, we identify two distinct paradigms of resistance to Smo inhibition. Sufu mutations lead to maintenance of the Shh pathway in the presence of Smo inhibitors. Alternatively activation of the RAS/MAPK pathway circumvents Shh pathway-dependency, drives tumor growth and enhances metastatic behavior. Strikingly, in BCC patients treated with Smo inhibitor, squamous cell cancers with RAS/MAPK activation emerged from the antecedent BCC tumors. Together these findings reveal a critical role of RAS/MAPK pathway in drug resistance and tumor evolution of Shh pathway-dependent tumors. PMID:26130651

  3. MicroRNA-566 activates EGFR signaling and its inhibition sensitizes glioblastoma cells to nimotuzumab

    PubMed Central

    2014-01-01

    Background Epidermal growth factor receptor (EGFR) is amplified in 40% of human glioblastomas. However, most glioblastoma patients respond poorly to anti-EGFR therapy. MicroRNAs can function as either oncogenes or tumor suppressor genes, and have been shown to play an important role in cancer cell proliferation, invasion and apoptosis. Whether microRNAs can impact the therapeutic effects of EGFR inhibitors in glioblastoma is unknown. Methods miR-566 expression levels were detected in glioma cell lines, using real-time quantitative RT-PCR (qRT-PCR). Luciferase reporter assays and Western blots were used to validate VHL as a direct target gene of miR-566. Cell proliferation, invasion, cell cycle distribution and apoptosis were also examined to confirm whether miR-566 inhibition could sensitize anti-EGFR therapy. Results In this study, we demonstrated that miR-566 is up-regulated in human glioma cell lines and inhibition of miR-566 decreased the activity of the EGFR pathway. Lentiviral mediated inhibition of miR-566 in glioblastoma cell lines significantly inhibited cell proliferation and invasion and led to cell cycle arrest in the G0/G1 phase. In addition, we identified von Hippel-Lindau (VHL) as a novel functional target of miR-566. VHL regulates the formation of the β-catenin/hypoxia-inducible factors-1α complex under miR-566 regulation. Conclusions miR-566 activated EGFR signaling and its inhibition sensitized glioblastoma cells to anti-EGFR therapy. PMID:24650032

  4. Inhibition of subcutaneously implanted human pituitary tumor cells in nude mice by LRIG1.

    PubMed

    Wang, X; He, X J; Xu, H Q; Chen, Z W; Fan, H H

    2016-05-06

    The aim of this study was to explore the inhibition of subcutaneously implanted human pituitary tumor cells in nude mice by LRIG1 and its mechanism. For this study, athymic nude mice were injected with either normal pituitary tumor RC-4B/C cells or LRIG1-transfected RC-4B/C cells. We then calculated the volume inhibition rate of the tumors, as well as the apoptosis index of tumor cells and the expression of Ras, Raf, AKt, and ERK mRNA in tumor cells. Tumor cell morphological and structural changes were also observed under electron microscope. Our data showed that subcutaneous tumor growth was slowed or even halted in LRIG1-transfected tumors. The tumor volumes were significantly different between the two groups of mice (χ2 = 2.14, P < 0.05). The tumor apoptosis index was found to be 8.72% in the control group and 39.7% in LRIG1-transfected mice (χ2 = 7.59, P < 0.05). The levels of Ras, Raf, and AKt mRNA in LRIG1-transfected RC-4B/C cells were significantly reduced after transfection (P < 0.01). Transfected subcutaneous tumor cells appeared to be in early or late apoptosis under an electron microscope, while only a few subcutaneous tumor cells appeared to be undergoing apoptosis in the control group. In conclusion, the LRIG1 gene is able to inhibit proliferation and promote apoptosis in subcutaneously implanted human pituitary tumors in nude mice. The mechanism of LRIG1 may involve the inhibition of the PI3K/ Akt and Ras/Raf/ERK signal transduction pathways.

  5. miR-25 modulates NSCLC cell radio-sensitivity through directly inhibiting BTG2 expression

    SciTech Connect

    He, Zhiwei Liu, Yi Xiao, Bing Qian, Xiaosen

    2015-02-13

    A large proportion of the NSCLC patients were insensitive to radiotherapy, but the exact mechanism is still unclear. This study explored the role of miR-25 in regulating sensitivity of NSCLC cells to ionizing radiation (IR) and its downstream targets. Based on measurement in tumor samples from NSCLC patients, this study found that miR-25 expression is upregulated in both NSCLC and radio-resistant NSCLC patients compared the healthy and radio-sensitive controls. In addition, BTG expression was found negatively correlated with miR-25a expression in the both tissues and cells. By applying luciferase reporter assay, we verified two putative binding sites between miR-25 and BTG2. Therefore, BTG2 is a directly target of miR-25 in NSCLC cancer. By applying loss-and-gain function analysis in NSCLC cell lines, we demonstrated that miR-25-BTG2 axis could directly regulated BTG2 expression and affect radiotherapy sensitivity of NSCLC cells. - Highlights: • miR-25 is upregulated, while BTG2 is downregulated in radioresistant NSCLC patients. • miR-25 modulates sensitivity to radiation induced apoptosis. • miR-25 directly targets BTG2 and suppresses its expression. • miR-25 modulates sensitivity to radiotherapy through inhibiting BTG2 expression.

  6. Aromatase Inhibition Reduces Insulin Sensitivity in Healthy Men

    PubMed Central

    Homer, Natalie Z. M.; Faqehi, Abdullah M. M.; Upreti, Rita; Livingstone, Dawn E.; McInnes, Kerry J.; Andrew, Ruth; Walker, Brian R.

    2016-01-01

    Context: Deficiency of aromatase, the enzyme that catalyzes the conversion of androgens to estrogens, is associated with insulin resistance in humans and mice. Objective: We hypothesized that pharmacological aromatase inhibition results in peripheral insulin resistance in humans. Design: This was a double-blind, randomized, controlled, crossover study. Setting: The study was conducted at a clinical research facility. Participants: Seventeen healthy male volunteers (18–50 y) participated in the study. Intervention: The intervention included oral anastrozole (1 mg daily) and placebo, each for 6 weeks with a 2-week washout period. Main Outcome Measure: Glucose disposal and rates of lipolysis were measured during a stepwise hyperinsulinemic euglycemic clamp. Data are mean (SEM). Results: Anastrozole therapy resulted in significant estradiol suppression (59.9 ± 3.6 vs 102.0 ± 5.7 pmol/L, P = < .001) and a more modest elevation of total T (25.8 ± 1.2 vs 21.4 ± 0.7 nmol/L, P = .003). Glucose infusion rate, during the low-dose insulin infusion, was lower after anastrozole administration (12.16 ± 1.33 vs 14.15 ± 1.55 μmol/kg·min, P = .024). No differences in hepatic glucose production or rate of lipolysis were observed. Conclusion: Aromatase inhibition reduces insulin sensitivity, with respect to peripheral glucose disposal, in healthy men. Local generation and action of estradiol, at the level of skeletal muscle, is likely to be an important determinant of insulin sensitivity. PMID:26967690

  7. Simvastatin inhibits tumor angiogenesis in HER2-overexpressing human colorectal cancer.

    PubMed

    Li, Gang; Zheng, Junhua; Xu, Bin; Ling, Jie; Qiu, Wei; Wang, Yongbing

    2017-01-01

    Overexpression of the HER2 oncogene contributes to tumor angiogenesis, which is an essential hallmark of cancer. Simvastatin has been reported to exhibit antitumor activities in several cancers; however, its roles and molecular mechanismsin the regulation of colorectal angiogenesis remain to be clarified. Here, we show that colon cancer cells express high levels of VEGF, total HER2 and phosphorylated HER2, and simvastatin apparently decreased their expression in HER2-overexpressing colon cancer cells. Simvastatin pretreatment reduced endothelial tube formation in vitro and microvessel density in vivo. Furthermore, simvastatin markedly inhibited tumor angiogenesis even in the presence of heregulin (HRG)-β1 (a HER2 co-activator) pretreatment in HER2+ tumor cells. Mechanistic investigation showed that simvastatin significantly abrogated HER2-induced tumor angiogenesis by inhibiting VEGF secretion. Together, these results provide a novel mechanism underlying the simvastatin-induced inhibition of tumor angiogenesis through regulating HER2/VEGF axis.

  8. Flaviviruses Are Sensitive to Inhibition of Thymidine Synthesis Pathways

    PubMed Central

    Fischer, Matthew A.; Smith, Jessica L.; Shum, David; Stein, David A.; Parkins, Christopher; Bhinder, Bhavneet; Radu, Constantin; Hirsch, Alec J.; Djaballah, Hakim; Nelson, Jay A.

    2013-01-01

    Dengue virus has emerged as a global health threat to over one-third of humankind. As a positive-strand RNA virus, dengue virus relies on the host cell metabolism for its translation, replication, and egress. Therefore, a better understanding of the host cell metabolic pathways required for dengue virus infection offers the opportunity to develop new approaches for therapeutic intervention. In a recently described screen of known drugs and bioactive molecules, we observed that methotrexate and floxuridine inhibited dengue virus infections at low micromolar concentrations. Here, we demonstrate that all serotypes of dengue virus, as well as West Nile virus, are highly sensitive to both methotrexate and floxuridine, whereas other RNA viruses (Sindbis virus and vesicular stomatitis virus) are not. Interestingly, flavivirus replication was restored by folinic acid, a thymidine precursor, in the presence of methotrexate and by thymidine in the presence of floxuridine, suggesting an unexpected role for thymidine in flavivirus replication. Since thymidine is not incorporated into RNA genomes, it is likely that increased thymidine production is indirectly involved in flavivirus replication. A possible mechanism is suggested by the finding that p53 inhibition restored dengue virus replication in the presence of floxuridine, consistent with thymidine-less stress triggering p53-mediated antiflavivirus effects in infected cells. Our data reveal thymidine synthesis pathways as new and unexpected therapeutic targets for antiflaviviral drug development. PMID:23824813

  9. SKI knockdown inhibits human melanoma tumor growth in vivo.

    PubMed

    Chen, Dahu; Lin, Qiushi; Box, Neil; Roop, Dennis; Ishii, Shunsuke; Matsuzaki, Koichi; Fan, Tao; Hornyak, Thomas J; Reed, Jon A; Stavnezer, Ed; Timchenko, Nikolai A; Medrano, Estela E

    2009-12-01

    The SKI protein represses the TGF-beta tumor suppressor pathway by associating with the Smad transcription factors. SKI is upregulated in human malignant melanoma tumors in a disease-progression manner and its overexpression promotes proliferation and migration of melanoma cells in vitro. The mechanisms by which SKI antagonizes TGF-beta signaling in vivo have not been fully elucidated. Here we show that human melanoma cells in which endogenous SKI expression was knocked down by RNAi produced minimal orthotopic tumor xenograft nodules that displayed low mitotic rate and prominent apoptosis. These minute tumors exhibited critical signatures of active TGF-beta signaling including high levels of nuclear Smad3 and p21(Waf-1), which are not found in the parental melanomas. To understand how SKI promotes tumor growth we used gain- and loss-of-function approaches and found that simultaneously to blocking the TGF-beta-growth inhibitory pathway, SKI promotes the switch of Smad3 from tumor suppression to oncogenesis by favoring phosphorylations of the Smad3 linker region in melanoma cells but not in normal human melanocytes. In this context, SKI is required for preventing TGF-beta-mediated downregulation of the oncogenic protein c-MYC, and for inducing the plasminogen activator inhibitor-1, a mediator of tumor growth and angiogenesis. Together, the results indicate that SKI exploits multiple regulatory levels of the TGF-beta pathway and its deficiency restores TGF-beta tumor suppressor and apoptotic activities in spite of the likely presence of oncogenic mutations in melanoma tumors.

  10. DlgR2 knockdown boosts dendritic cell activity and inhibits hepatocellular carcinoma tumor in-situ growth.

    PubMed

    Lu, Zhen; Xia, Yun-Hong; Zhao, Min; Zhang, Bing; Dai, Wen-Ting; Ding, Lu; Hu, Li-Xia; Bi, Jin-Ling; Jiang, Guo-Lin

    2017-08-15

    Tumor-specific hepatic stellate cells (tHSCs) positively participate in human hepatocellular carcinoma (HCC) tumorigenesis and progression. Our previous studies have shown that tHSCs co-culture with dendritic cells (DCs) induced DIgR2 (dendritic cell-derived immunoglobulin receptor 2) expression. The latter is a member of IgSF inhibitory receptor suppressing DCs-initiated antigen-specific T-cell responses. In the current study, we show that hepatic artery injection of DlgR2 siRNA significantly inhibited in-situ HCC xenograft growth in rat livers. Further, 5-FU-medied inhibition of in-situ HCC growth was dramatically sensitized with DlgR2 silence. DlgR2 siRNA injection indeed downregulated DlgR2 in ex-vivo cultured tumor-derived DCs (tDCs). More importantly, tDCs activity was boosted following DlgR2 siRNA. These cells presented with upregulated CD80, CD86 and MHC-II. Production of interleukin-12 and tumor necrosis factor-α was also increased in the DlgR2-silenced tDCs. We propose that DlgR2 knockdown likely boosts the activity of tumor-associated DCs, and inhibits growth of in-situ HCC xenografts.

  11. Tumor suppressor WWOX binds to ΔNp63α and sensitizes cancer cells to chemotherapy.

    PubMed

    Salah, Z; Bar-mag, T; Kohn, Y; Pichiorri, F; Palumbo, T; Melino, G; Aqeilan, R I

    2013-01-31

    The WWOX tumor suppressor is a WW domain-containing protein. Its function in the cell has been shown to be mediated, in part, by interacting with its partners through its first WW (WW1) domain. Here, we demonstrated that WWOX via WW1 domain interacts with p53 homolog, ΔNp63α. This protein-protein interaction stabilizes ΔNp63α, through antagonizing function of the E3 ubiquitin ligase ITCH, inhibits nuclear translocation of ΔNp63α into the nucleus and suppresses ΔNp63α transactivation function. Additionally, we found that this functional crosstalk reverses cancer cells resistance to cisplatin, mediated by ΔNp63α, and consequently renders these cells more sensitive to undergo apoptosis. These findings suggest a functional crosstalk between WWOX and ΔNp63α in tumorigenesis.

  12. Tumor suppressor WWOX binds to ΔNp63α and sensitizes cancer cells to chemotherapy

    PubMed Central

    Salah, Z; Bar-mag, T; Kohn, Y; Pichiorri, F; Palumbo, T; Melino, G; Aqeilan, R I

    2013-01-01

    The WWOX tumor suppressor is a WW domain-containing protein. Its function in the cell has been shown to be mediated, in part, by interacting with its partners through its first WW (WW1) domain. Here, we demonstrated that WWOX via WW1 domain interacts with p53 homolog, ΔNp63α. This protein–protein interaction stabilizes ΔNp63α, through antagonizing function of the E3 ubiquitin ligase ITCH, inhibits nuclear translocation of ΔNp63α into the nucleus and suppresses ΔNp63α transactivation function. Additionally, we found that this functional crosstalk reverses cancer cells resistance to cisplatin, mediated by ΔNp63α, and consequently renders these cells more sensitive to undergo apoptosis. These findings suggest a functional crosstalk between WWOX and ΔNp63α in tumorigenesis. PMID:23370280

  13. Novel Therapeutic Targets to Inhibit Tumor Microenvironment Induced Castration-resistant Prostate Cancer

    DTIC Science & Technology

    2015-10-01

    AWARD NUMBER: W81XWH-13-1-0163 TITLE: Novel Therapeutic Targets to Inhibit Tumor Microenvironment Induced Castration-resistant Prostate Cancer ...Castration-resistant Prostate Cancer 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Feng Yang, Ph.D. 5d. PROJECT NUMBER 5e. TASK...Annual Progress Report W81XWH-13-1-0163 Novel Therapeutic Targets to Inhibit Tumor Microenvironment Induced Castration-resistant Prostate Cancer

  14. Activated Kupffer cells inhibit insulin sensitivity in obese mice

    PubMed Central

    Tencerova, Michaela; Aouadi, Myriam; Vangala, Pranitha; Nicoloro, Sarah M.; Yawe, Joseph C.; Cohen, Jessica L.; Shen, Yuefei; Garcia-Menendez, Lorena; Pedersen, David J.; Gallagher-Dorval, Karen; Perugini, Richard A.; Gupta, Olga T.; Czech, Michael P.

    2015-01-01

    Obesity promotes insulin resistance associated with liver inflammation, elevated glucose production, and type 2 diabetes. Although insulin resistance is attenuated in genetic mouse models that suppress systemic inflammation, it is not clear whether local resident macrophages in liver, denoted Kupffer cells (KCs), directly contribute to this syndrome. We addressed this question by selectively silencing the expression of the master regulator of inflammation, NF-κB, in KCs in obese mice. We used glucan-encapsulated small interfering RNA particles (GeRPs) that selectively silence gene expression in macrophages in vivo. Following intravenous injections, GeRPs containing siRNA against p65 of the NF-κB complex caused loss of NF-κB p65 expression in KCs without disrupting NF-κB in hepatocytes or macrophages in other tissues. Silencing of NF-κB expression in KCs in obese mice decreased cytokine secretion and improved insulin sensitivity and glucose tolerance without affecting hepatic lipid accumulation. Importantly, GeRPs had no detectable toxic effect. Thus, KCs are key contributors to hepatic insulin resistance in obesity and a potential therapeutic target for metabolic disease.—Tencerova, M., Aouadi, M., Vangala, P., Nicoloro, S. M., Yawe, J. C., Cohen, J. L., Shen, Y., Garcia-Menendez, L., Pedersen, D. J., Gallagher-Dorval, K., Perugini, R. A., Gupta, O. T., Czech, M. P. Activated Kupffer cells inhibit insulin sensitivity in obese mice. PMID:25805830

  15. Direct endothelial junction restoration results in significant tumor vascular normalization and metastasis inhibition in mice

    PubMed Central

    Agrawal, Vijayendra; Maharjan, Sony; Kim, Kyeojin; Kim, Nam-Jung; Son, Jimin; Lee, Keunho; Choi, Hyun-Jung; Rho, Seung-Sik; Ahn, Sunjoo; Won, Moo-Ho; Ha, Sang-Jun; Koh, Gou Young; Kim, Young-Myeong; Suh, Young-Ger; Kwon, Young-Guen

    2014-01-01

    Tumor blood vessels are leaky and immature, which causes inadequate blood supply to tumor tissues resulting in hypoxic microenvironment and promotes metastasis. Here we have explored tumor vessel modulating activity of Sac-1004, a recently developed molecule in our lab, which directly potentiates VE-cadherin-mediated endothelial cell junction. Sac-1004 could enhance vascular junction integrity in tumor vessels and thereby inhibit vascular leakage and enhance vascular perfusion. Improved perfusion enabled Sac-1004 to have synergistic anti-tumor effect on cisplatin-mediated apoptosis of tumor cells. Interestingly, characteristics of normalized blood vessels namely reduced hypoxia, improved pericyte coverage and decreased basement membrane thickness were readily observed in tumors treated with Sac-1004. Remarkably, Sac-1004 was also able to inhibit lung and lymph node metastasis in MMTV and B16BL6 tumor models. This was in correlation with a reduction in epithelial-to-mesenchymal transition of tumor cells with considerable diminution in expression of related transcription factors. Moreover, cancer stem cell population dropped substantially in Sac-1004 treated tumor tissues. Taken together, our results showed that direct restoration of vascular junction could be a significant strategy to induce normalization of tumor blood vessels and reduce metastasis. PMID:24811731

  16. Levetiracetam enhances p53-mediated MGMT inhibition and sensitizes glioblastoma cells to temozolomide

    PubMed Central

    Bobustuc, George C.; Baker, Cheryl H.; Limaye, Arati; Jenkins, Wayne D.; Pearl, Gary; Avgeropoulos, Nicholas G.; Konduri, Santhi D.

    2010-01-01

    Antiepileptic drugs (AEDs) are frequently used to treat seizures in glioma patients. AEDs may have an unrecognized impact in modulating O6-methylguanine-DNA methyltransferase (MGMT), a DNA repair protein that has an important role in tumor cell resistance to alkylating agents. We report that levetiracetam (LEV) is the most potent MGMT inhibitor among several AEDs with diverse MGMT regulatory actions. In vitro, when used at concentrations within the human therapeutic range for seizure prophylaxis, LEV decreases MGMT protein and mRNA expression levels. Chromatin immunoprecipitation analysis reveals that LEV enhances p53 binding on the MGMT promoter by recruiting the mSin3A/histone deacetylase 1 (HDAC1) corepressor complex. However, LEV does not exert any MGMT inhibitory activity when the expression of either p53, mSin3A, or HDAC1 is abrogated. LEV inhibits malignant glioma cell proliferation and increases glioma cell sensitivity to the monofunctional alkylating agent temozolomide. In 4 newly diagnosed patients who had 2 craniotomies 7–14 days apart, prior to the initiation of any tumor-specific treatment, samples obtained before and after LEV treatment showed the inhibition of MGMT expression. Our results suggest that the choice of AED in patients with malignant gliomas may have an unrecognized impact in clinical practice and research trial design. PMID:20525765

  17. Inhibition of cyclic AMP response element-directed transcription by decoy oligonucleotides enhances tumor-specific radiosensitivity

    SciTech Connect

    Park, Serk In; Park, Sung-Jun; Lee, Junghan; Kim, Hye Eun; Park, Su Jin; Sohn, Jeong-Won; Park, Yun Gyu

    2016-01-15

    The radiation stress induces cytotoxic responses of cell death as well as cytoprotective responses of cell survival. Understanding exact cellular mechanism and signal transduction pathways is important in improving cancer radiotherapy. Increasing evidence suggests that cyclic AMP response element binding protein (CREB)/activating transcription factor (ATF) family proteins act as a survival factor and a signaling molecule in response to stress. We postulated that CREB inhibition via CRE decoy oligonucleotide increases tumor cell sensitization to γ-irradiation-induced cytotoxic stress. In the present study, we demonstrate that CREB phosphorylation and CREB DNA-protein complex formation increased in time- and radiation dose-dependent manners, while there was no significant change in total protein level of CREB. In addition, CREB was phosphorylated in response to γ-irradiation through p38 MAPK pathway. Further investigation revealed that CREB blockade by decoy oligonucleotides functionally inhibited transactivation of CREB, and significantly increased radiosensitivity of multiple human cancer cell lines including TP53- and/or RB-mutated cells with minimal effects on normal cells. We also demonstrate that tumor cells ectopically expressing dominant negative mutant CREB (KCREB) and the cells treated with p38 MAPK inhibitors were more sensitive to γ-irradiation than wild type parental cells or control-treated cells. Taken together, we conclude that CREB protects tumor cells from γ-irradiation, and combination of CREB inhibition plus ionizing radiation will be a promising radiotherapeutic approach. - Highlights: • γ-Irradiation induced CREB phosphorylation and CRE-directed transcription in tumor. • γ-Irradiation-induced transcriptional activation of CREB was via p38 MAPK pathway. • CRE blockade increased radiosensitivity of tumor cells but not of normal cells. • CRE decoy oligonucleotides or p38 MAPK inhibitors can be used as radiosensitizers.

  18. A new role for GABA: inhibition of tumor cell migration.

    PubMed

    Ortega, Arturo

    2003-04-01

    GABA, the main inhibitory neurotransmitter in the vertebrate brain, participates outside the CNS in diverse functions such as platelet aggregation and the acrosomal reaction in spermatozoa. A recent study now demonstrates that GABA inhibits the migration of colon carcinoma cells, paving the way to the development of specific pharmacological agents that delay or inhibit invasion and metastasis of various cancer types.

  19. Ibuprofen Inhibits Colitis-Induced Overexpression of Tumor-Related Rac1b1

    PubMed Central

    Matos, Paulo; Kotelevets, Larissa; Goncalves, Vania; Henriques, Andreia; Zerbib, Philippe; Moyer, Mary Pat; Chastre, Eric; Jordan, Peter

    2013-01-01

    The serrated pathway to colorectal tumor formation involves oncogenic mutations in the BRAF gene, which are sufficient for initiation of hyperplastic growth but not for tumor progression. A previous analysis of colorectal tumors revealed that overexpression of splice variant Rac1b occurs in around 80% of tumors with mutant BRAF and both events proved to cooperate in tumor cell survival. Here, we provide evidence for increased expression of Rac1b in patients with inflamed human colonic mucosa as well as following experimentally induced colitis in mice. The increase of Rac1b in the mouse model was specifically prevented by the nonsteroidal anti-inflammatory drug ibuprofen, which also inhibited Rac1b expression in cultured HT29 colorectal tumor cells through a cyclooxygenase inhibition.independent mechanism. Accordingly, the presence of ibuprofen led to a reduction of HT29 cell survival in vitro and inhibited Rac1b-dependent tumor growth of HT29 xenografts. Together, our results suggest that stromal cues, namely, inflammation, can trigger changes in Rac1b expression in the colon and identify ibuprofen as a highly specific and efficient inhibitor of Rac1b overexpression in colorectal tumors. Our data suggest that the use of ibuprofen may be beneficial in the treatment of patients with serrated colorectal tumors or with inflammatory colon syndromes. PMID:23359345

  20. Alternating electric fields (TTFields) inhibit metastatic spread of solid tumors to the lungs.

    PubMed

    Kirson, Eilon D; Giladi, Moshe; Gurvich, Zoya; Itzhaki, Aviran; Mordechovich, Daniel; Schneiderman, Rosa S; Wasserman, Yoram; Ryffel, Bernhard; Goldsher, Dorit; Palti, Yoram

    2009-01-01

    Tumor treating fields (TTFields) are low intensity, intermediate frequency, alternating electric fields used to treat cancerous tumors. This novel treatment modality effectively inhibits the growth of solid tumors in vivo and has shown promise in pilot clinical trials in patients with advanced stage solid tumors. TTFields were tested for their potential to inhibit metastatic spread of solid tumors to the lungs in two animal models: (1) Mice injected with malignant melanoma cells (B16F10) into the tail vein, (2) New Zealand White rabbits implanted with VX-2 tumors within the kidney capsule. Mice and rabbits were treated using two-directional TTFields at 100-200 kHz. Animals were either monitored for survival, or sacrificed for pathological and histological analysis of the lungs. The total number of lung surface metastases and the absolute weight of the lungs were both significantly lower in TTFields treated mice then in sham control mice. TTFields treated rabbits survived longer than sham control animals. This extension in survival was found to be due to an inhibition of metastatic spread, seeding or growth in the lungs of TTFields treated rabbits compared to controls. Histologically, extensive peri- and intra-tumoral immune cell infiltration was seen in TTFields treated rabbits only. These results raise the possibility that in addition to their proven inhibitory effect on the growth of solid tumors, TTFields may also have clinical benefit in the prevention of metastatic spread from primary tumors.

  1. Inhibition of melanocortin 1 receptor slows melanoma growth, reduces tumor heterogeneity and increases survival

    PubMed Central

    Kansal, Rita G.; McCravy, Matthew S.; Basham, Jacob H.; Earl, Joshua A.; McMurray, Stacy L.; Starner, Chelsey J.

    2016-01-01

    Melanoma risk is increased in patients with mutations of melanocortin 1 receptor (MC1R) yet the basis for the increased risk remains unknown. Here we report in vivo evidence supporting a critical role for MC1R in regulating melanoma tumor growth and determining overall survival time. Inhibition of MC1R by its physiologically relevant competitive inhibitor, agouti signaling protein (ASIP), reduced melanin synthesis and morphological heterogeneity in murine B16-F10 melanoma cells. In the lungs of syngeneic C57BL/6 mice, mCherry-marked, ASIP-secreting lung tumors inhibited MC1R on neighboring tumors lacking ASIP in a dose dependent manner as evidenced by a proportional loss of pigment in tumors from mice injected with 1:1, 3:1 and 4:1 mixtures of parental B16-F10 to ASIP-expressing tumor cells. ASIP-expressing B16-F10 cells formed poorly pigmented tumors in vivo that correlated with a 20% longer median survival than those bearing parental B16-F10 tumors (p=0.0005). Mice injected with 1:1 mixtures also showed survival benefit (p=0.0054), whereas injection of a 4:1 mixture showed no significant difference in survival. The longer survival time of mice bearing ASIP-expressing tumors correlated with a significantly slower growth rate than parental B16-F10 tumors as judged by quantification of numbers of tumors and total tumor load (p=0.0325), as well as a more homogeneous size and morphology of ASIP-expressing lung tumors. We conclude that MC1R plays an important role in regulating melanoma growth and morphology. Persistent inhibition of MC1R provided a significant survival advantage resulting in part from slower tumor growth, establishing MC1R as a compelling new molecular target for metastatic melanoma. PMID:27028866

  2. MiR-122 targets VEGFC in bladder cancer to inhibit tumor growth and angiogenesis

    PubMed Central

    Wang, Yi; Xing, Qing-Fei; Liu, Xiao-Qiang; Guo, Zhan-Jun; Li, Chang-Ying; Sun, Guang

    2016-01-01

    Previous studies indicate that microRNA-122 (miR-122) is down-regulated in several cancer cells and regulates cell apoptosis, proliferation, metastasis, and tumor angiogenesis. However, the mount of miR-122 in bladder cancer and the pivotal molecular mechanisms of miR-122 used to regulate bladder carcinogenesis and angiogenesis remain to be clarified. Here, we reveal that miR-122 expression is down-regulated in human bladder cancer tissues and cell lines. MiR-122 represses vascular endothelial growth factor C (VEGFC) post-transcriptional expression by directly binding to its 3’-UTR. The protein kinase B (AKT) and mammalian target of rapamycin (mTOR), which are the most important downstream molecules of VEGFC, are also decreased in bladder cancer cell after miR-122 overexpression. Furthermore, miR-122 over-expression decreases bladder cancer cell migration, invasion, colony formation in vitro and slow bladder cancer growth and angiogenesis in vivo. Finally, miR-122 sensitizes bladder cancer cells to cisplatin-induced apoptosis. Taken together, these studies suggest that miR-122 serves as a tumor suppressor and down-regulating VEGFC expression, leading to the inhibition of bladder cancer growth and angiogenesis. PMID:27508026

  3. Sterol and triterpene derivatives from plants inhibit the effects of a tumor promoter, and sitosterol and betulinic acid inhibit tumor formation in mouse skin two-stage carcinogenesis.

    PubMed

    Yasukawa, K; Takido, M; Matsumoto, T; Takeuchi, M; Nakagawa, S

    1991-01-01

    A single topical application of 1 microgram of 12-O-tetradecanoylphorbol- 13-acetate (TPA) to the ears of mice was shown to induce edema, and this TPA-induced inflammation was inhibited by 4-methylsterol and triterpene derivatives. The ED50 of these compounds against TPA-induced inflammation was 0.1-3 mumol. Phytosterols had only slight inhibitory effects. Furthermore, application of 5 micrograms TPA to mouse skin rapidly caused accumulation of ornithine decarboxylase (ODC). Similarly, sitosterol and lupane-type triterpene derivatives markedly inhibited this TPA-induced ODC accumulation. In addition, 5 mumol betulinic acid markedly inhibited the promoting effect of 2.5 micrograms TPA applied twice weekly on skin tumor formation in mice initiated with 50 micrograms of 7,12-dimethylbenz[a]anthracene, and 5 mumol of sitosterol caused slight suppression. Thus, the inhibitory effects of sterol and triterpene derivatives on TPA-induced inflammation roughly parallelled their inhibitory activities against tumor promotion.

  4. Dual-targeted and pH-sensitive Doxorubicin Prodrug-Microbubble Complex with Ultrasound for Tumor Treatment

    PubMed Central

    Luo, Wanxian; Wen, Ge; Yang, Li; Tang, Jiao; Wang, Jianguo; Wang, Jihui; Zhang, Shiyu; Zhang, Li; Ma, Fei; Xiao, Liling; Wang, Ying; Li, Yingjia

    2017-01-01

    In this study, we investigated the potential of a dual-targeted pH-sensitive doxorubicin prodrug-microbubble complex (DPMC) in ultrasound (US)-assisted antitumor therapy. The doxorubicin prodrug (DP) consists of a succinylated-heparin carrier conjugated with doxorubicin (DOX) via hydrazone linkage and decorated with dual targeting ligands, folate and cRGD peptide. Combination of microbubble (MB) and DP, generated via avidin-biotin binding, promoted intracellular accumulation and improved therapeutic efficiency assisted by US cavitation and sonoporation. Aggregates of prepared DP were observed with an inhomogeneous size distribution (average diameters: 149.6±29.8 nm and 1036.2±38.8 nm, PDI: 1.0) while DPMC exhibited a uniform distribution (average diameter: 5.804±2.1 μm), facilitating its usage for drug delivery. Notably, upon US exposure, DPMC was disrupted and aggregated DP dispersed into homogeneous small-sized nanoparticles (average diameter: 128.6±42.3 nm, PDI: 0.21). DPMC could target to angiogenic endothelial cells in tumor region via αvβ3-mediated recognition and subsequently facilitate its specific binding to tumor cells mediated via recognition of folate receptor (FR) after US exposure. In vitro experiments showed higher tumor specificity and killing ability of DPMC with US than free DOX and DP for breast cancer MCF-7 cells. Furthermore, significant accumulation and specificity for tumor tissues of DPMC with US were detected using in vivo fluorescence and ultrasound molecular imaging, indicating its potential to integrate tumor imaging and therapy. In particular, through inducing apoptosis, inhibiting cell proliferation and antagonizing angiogenesis, DPMC with US produced higher tumor inhibition rates than DOX or DPMC without US in MCF-7 xenograft tumor-bearing mice while inducing no obvious body weight loss. Our strategy provides an effective platform for the delivery of large-sized or aggregated particles to tumor sites, thereby extending their

  5. Generation of an immortalized human CD4+ T cell clone inhibiting tumor growth in mice.

    PubMed

    Pecher, G; Harnack, U; Günther, M; Hummel, M; Fichtner, I; Schenk, J A

    2001-05-18

    Tumor antigen-specific T cell clones represent a useful tool in tumor immunology; however, their long-term culture is limited. To generate an immortalized cytotoxic T cell clone against the human tumor antigen mucin, we exposed a previously generated T cell culture to Herpesvirus saimiri. We obtained an immortalized human CD4+ T cell clone, termed SITAM. Clonality of these cells was shown by analysis of the alpha/beta-T cell receptor (TCR) repertoire. Cytolytic activity was demonstrated against several mucin-expressing tumor cell lines and could not be detected against non-mucin-expressing cells. SITAM cells maintained their features stably for 2 years. Furthermore, growth of the tumor cell line Capan-2 in NOD/SCID mice was inhibited when SITAM cells were coinjected subcutaneously with tumor cells. SITAM cells provide an unlimited source of clonal T cells for analysis of tumor recognition and may be of help in TCR-targeted immunotherapy. Copyright 2001 Academic Press.

  6. Inhibition of Glut1 by WZB117 sensitizes radioresistant breast cancer cells to irradiation.

    PubMed

    Zhao, Fei; Ming, Jia; Zhou, Yan; Fan, Linjun

    2016-05-01

    Breast cancer is the most common type of cancer with high incidence in women. Currently, identifying new therapies that selectively inhibit tumor growth without damaging normal tissue are a major challenge of cancer research. One of the features of cancer cells is that they do not consume more oxygen even under normal oxygen circumstances but prefer to aerobic glycolysis through the enhanced catabolism of glucose and glutamine. In this study, we investigate the mechanisms of the radioresistance in breast cancer cells. Human breast cancer cells MDA-MB-231 and MCF-7 were treated with radiation alone, Glut1 inhibitor alone or the combination of both to evaluate cell glucose metabolism and apoptosis. By the establishment of radioresistant cell line, we investigate the mechanisms of the combined treatments of radiation with Glut1 inhibitor in the radioresistant cells. The glucose metabolism and the expression of Glut1 are significantly stimulated by radiotherapy. We report the radioresistant breast cancer cells exhibit upregulated Glut1 expression and glucose metabolism. In addition, we observed overexpression of Glut1 renders breast cancer cells resistant to radiation and knocking down of Glut1 sensitizes breast cancer cells to radiation. We treated breast cancer cells with radiation and WZB117 which inhibits Glut1 expression and glucose metabolism and found the combination of WZB117 and radiation exhibits synergistically inhibitory effects on breast cancer cells. Finally, we demonstrate the inhibition of Glut1 re-sensitizes the radioresistant cancer cells to radiation. This study reveals the roles of Glut1 in the radiosensitivity of human breast cancer. It will provide new mechanisms and strategies for the sensitization of cancer cells to radiotherapy through regulation of glucose metabolism.

  7. Tumor acidosis enhances cytotoxic effects and autophagy inhibition by salinomycin on cancer cell lines and cancer stem cells

    PubMed Central

    Pellegrini, Paola; Dyczynski, Matheus; Sbrana, Francesca Vittoria; Karlgren, Maria; Buoncervello, Maria; Hägg-Olofsson, Maria; Ma, Ran; Hartman, Johan; Bajalica-Lagercrantz, Svetlana; Grander, Dan; Kharaziha, Pedram; De Milito, Angelo

    2016-01-01

    Sustained autophagy contributes to the metabolic adaptation of cancer cells to hypoxic and acidic microenvironments. Since cells in such environments are resistant to conventional cytotoxic drugs, inhibition of autophagy represents a promising therapeutic strategy in clinical oncology. We previously reported that the efficacy of hydroxychloroquine (HCQ), an autophagy inhibitor under clinical investigation is strongly impaired in acidic tumor environments, due to poor uptake of the drug, a phenomenon widely associated with drug resistance towards many weak bases. In this study we identified salinomycin (SAL) as a potent inhibitor of autophagy and cytotoxic agent effective on several cancer cell lines under conditions of transient and chronic acidosis. Since SAL has been reported to specifically target cancer-stem cells (CSC), we used an established model of breast CSC and CSC derived from breast cancer patients to examine whether this specificity may be associated with autophagy inhibition. We indeed found that CSC-like cells are more sensitive to autophagy inhibition compared to cells not expressing CSC markers. We also report that the ability of SAL to inhibit mammosphere formation from CSC-like cells was dramatically enhanced in acidic conditions. We propose that the development and use of clinically suitable SAL derivatives may result in improved autophagy inhibition in cancer cells and CSC in the acidic tumor microenvironment and lead to clinical benefits. PMID:27248168

  8. PID1 IS A NOVEL SENSITIZER OF BRAIN TUMOR CELLS TO CHEMOTHERAPY

    PubMed Central

    Erdreich-Epstein, Anat; Xu, Jingying; Ren, Xiuhai

    2014-01-01

    BACKGROUND: PID1 is a phosphotyrosine binding domain-containing protein of unknown function in cancer. We recently provided the first report of PID1 in brain tumors (and in cancer). PID1 inhibits growth and proliferation and induces cell death, apoptosis and mitochondrial depolarization in glioblastoma, medulloblastoma and ATRT cell lines. PID1 siRNA had the opposite effect on mitochondrial depolarization. PID1 mRNA level was directly correlated with survival of patients with medulloblastoma or glioma: PID1 mRNA was lowest in tumor subgroups with the poorest prognosis and highest in the more favorable prognosis groups within each diagnosis. The mechanism by which PID1 affects these tumors is currently unknown, and is the focus of studies in our laboratory. METHODS: Experiments were conducted in tissue culture in primary and established cell lines using established methods to assess mRNA, proliferation and signal transduction. RESULTS: Since lower PID1 mRNA was associated with poorer outcome in medulloblastoma and gliomas and higher PID1 was associated with improved outcome, we hypothesized that PID1 level may affect responsiveness of these brain tumors to therapy: higher responsiveness in tumors with high PID1 and resistance when it is low. Indeed, while both cisplatin (10 µg/ml) or transient PID1 overexpression increased apoptosis of glioma and medulloblastoma cell lines (indicated by increased AnnexinV, caspase-3 cleavage and mitochondrial depolarization), combining cisplatin with PID1 caused a markedly higher effect than each alone. Moreover, knockdown of PID1 by siRNA inhibited the cisplatin-induced mitochondrial membrane depolarization and apoptosis (AnnexinV and caspase-3 cleavage), suggesting that PID1 may be required for cisplatin-induced apoptosis. This supports our hypothesis that PID1 may sensitize brain tumor cells to chemotherapy. Intriguingly, PID1 mRNA increased in response to cisplatin (5 µg/ml) as well as to etoposide (5 µg/ml) and vincristine

  9. Noscapine inhibits tumor growth in TMZ-resistant gliomas.

    PubMed

    Jhaveri, Niyati; Cho, Heeyeon; Torres, Shering; Wang, Weijun; Schönthal, Axel H; Petasis, Nicos A; Louie, Stan G; Hofman, Florence M; Chen, Thomas C

    2011-12-22

    Noscapine, a common oral antitussive agent, has been shown to have potent antitumor activity in a variety of cancers. Treatment of glioblastoma multiforme (GBM) with temozolomide (TMZ), its current standard of care, is problematic because the tumor generally recurs and is then resistant to this drug. We therefore investigated the effects of noscapine on human TMZ-resistant GBM tumors. We found that noscapine significantly decreased TMZ-resistant glioma cell growth and invasion. Using the intracranial xenograft model, we showed that noscapine increased survival of animals with TMZ-resistant gliomas. Thus noscapine can provide an alternative therapeutic approach for the treatment of TMZ-resistant gliomas.

  10. Inhibition of Rad51 sensitizes breast cancer cells with wild-type PTEN to olaparib.

    PubMed

    Zhao, Qian; Guan, Jiawei; Zhang, Zhiwei; Lv, Jian; Wang, Yulu; Liu, Likun; Zhou, Qi; Mao, Weifeng

    2017-10-01

    PTEN is a tumor suppressor gene well characterized as a phosphatase. However, more evidences demonstrate PTEN functions in DNA repair independent of its phosphatase activity, which affects the efficacy of DNA damage anti-tumoral drugs in treating cancer cells with PTEN variations. Using BT549 breast cancer cells, we studied the roles of PTEN in DNA repair and in sensitization of breast cancer cells to olaparib, a poly(ADP-ribose) polymerase (PARP) inhibitor. Comet assay showed PTEN promoted DNA repair. PTEN-deficient BT549 cells are sensitive to olaparib, which shows the synthetic lethality between PTEN and PARP1. We expressed PTEN in BT549 cells and found PTEN-proficient BT549 cells resist to olaparib. Western blot showed that PTEN up-regulated Rad51 expression, suggesting PTEN promotes DNA repair through Rad51-dependnent homologous recombination. We used 5μM olaparib or 5μM RI-1, a Rad51 inhibitor, to treat PTEN-proficient BT549 cells respectively. The immunofluorescent analysis showed the combination of olaparib and RI-1 induced more than 4-fold of γH2AX foci than either of them. MTT assay showed 5μM RI-1 did not change the survival of PTEN-proficient BT549 cells, however, this dose of RI-1 sensitized PTEN-proficient BT549 cells to olaparib. Consequently, these results demonstrate that inhibition of Rad51 can sensitize BT549 cells with wild type PTEN to olaparib, which would contribute to using PARP inhibitors in individual treatment of breast cancer patients with PTEN variations. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. Glutaminase inhibitor compound 968 inhibits cell proliferation and sensitizes paclitaxel in ovarian cancer

    PubMed Central

    Yuan, Lingqin; Sheng, Xiugui; Clark, Leslie H; Zhang, Lu; Guo, Hui; Jones, Hannah M; Willson, Adam K; Gehrig, Paola A; Zhou, Chunxiao; Bae-Jump, Victoria L

    2016-01-01

    Objective: Our overall goal was to investigate the anti-tumor activity of the glutaminase 1 (GLS1) Inhibitor compound 968 in ovarian cancer cells. The human ovarian cancer cell lines, HEY, SKOV3 and IGROV-1 were used. Cell proliferation was assessed by MTT assay after treatment with compound 968. Cell cycle progression and Annexin V expression were evaluated using Cellometer. Western blotting was performed to determine changes in GLS1, cellular stress and cell cycle checkpoints. Reactive oxygen species (ROS) and glutamate dehydrogenase (GDH) activity were assessed by ELISA assay. Compound 968 significantly inhibited cell proliferation and the expression of GLS1 in a dose-dependent manner in all three ovarian cancer cell lines. Compound 968 induced G1 phase cell cycle arrest and apoptosis. Treatment with compound 968 increased ROS levels and induced the protein expression of calnexin, binding immunoglobulin protein (BiP) and protein kinase RNA-like endoplasmic reticulum kinase (PERK). Deprivation of glutamine increased the sensitivity of cells to paclitaxel, and compound 968 sensitized cells to the anti-proliferative effects of paclitaxel. Compound 968 inhibited cell growth in ovarian cancer cells through induction of G1 phase cell cycle arrest, apoptosis and cellular stress, suggesting that targeting GLS1 provide a novel therapeutic strategy for ovarian cancer. PMID:27830010

  12. Inhibition of demethylase KDM6B sensitizes diffuse large B-cell lymphoma to chemotherapeutic drugs

    PubMed Central

    Mathur, Rohit; Sehgal, Lalit; Havranek, Ondrej; Köhrer, Stefan; Khashab, Tamer; Jain, Neeraj; Burger, Jan A.; Neelapu, Sattva S.; Davis, R. Eric; Samaniego, Felipe

    2017-01-01

    Histone methylation and demethylation regulate B-cell development, and their deregulation correlates with tumor chemoresistance in diffuse large B-cell lymphoma, limiting cure rates. Since histone methylation status correlates with disease aggressiveness and relapse, we investigated the therapeutic potential of inhibiting histone 3 Lys27 demethylase KDM6B, in vitro, using the small molecule inhibitor GSK-J4. KDM6B is overexpressed in the germinal center B-cell subtype of diffuse large B-cell lymphoma, and higher KDM6B levels are associated with worse survival in patients with diffuse large B-cell lymphoma treated with R-CHOP. GSK-J4-induced apoptosis was observed in five (SU-DHL-6, OCI-Ly1, Toledo, OCI-Ly8, SU-DHL-8) out of nine germinal center B-cell diffuse large B-cell lymphoma cell lines. Treatment with GSK-J4 predominantly resulted in downregulation of B-cell receptor signaling and BCL6. Cell lines expressing high BCL6 levels or CREBBP/EP300 mutations were sensitive to GSK-J4. Our results suggest that B-cell receptor-dependent downregulation of BCL6 is responsible for GSK-J4-induced cytotoxicity. Furthermore, GSK-J4-mediated inhibition of KDM6B sensitizes germinal center B-cell diffuse large B-cell lymphoma cells to chemotherapy agents that are currently utilized in treatment regimens for diffuse large B-cell lymphoma. PMID:27742770

  13. Inhibition of Phosphatidylinositol 3-Kinase/Akt Signaling Suppresses Tumor Cell Proliferation and Neuroendocrine Marker Expression in GI Carcinoid Tumors

    PubMed Central

    Pitt, Susan C.; Chen, Herbert; Kunnimalaiyaan, Muthusamy

    2010-01-01

    Background Over-activation of PI3K/Akt signaling facilitates tumor proliferation in several cancers. We have shown that various signal transduction pathways promote tumorigenesis in carcinoid tumors, which exhibit endogenously high levels of active, phosphorylated Akt. Therefore, we hypothesized that inhibition of the PI3K/Akt pathway would suppress carcinoid tumor cell growth and neuroendocrine (NE) marker production. Methods Human carcinoid BON cells were treated in vitro with LY294002, a PI3 kinase inhibitor, or transfected with Akt1 siRNA. Tumor cell proliferation was measured by MTT for six days. The effect of LY294002 or Akt1 siRNA treatment was assessed by western analysis. We examined the levels of phosphorylated Akt, total Akt, Akt1, and the NE markers human achaete-scute homolog1 (ASCL1) and chromogranin A (CgA). Results Treatment of BON cells with LY294002 reduced tumor cell proliferation (76%) in a dose-dependent manner. Growth also decreased in Akt1 siRNA transfected cells (29%). Levels of active, phosphorylated Akt and the NE tumor markers, ASCL1 and CgA, were diminished with both LY294002 and Akt1 siRNA treatments proportional to the degree of Akt inhibition. Total Akt, Akt2, and Akt3 levels were unaffected by these experiments. Conclusions These data indicate that PI3K/Akt signaling performs a critical role in human carcinoid tumor cell survival and NE hormone generation. Furthermore, the development of novel therapeutics targeting Akt1 or components of the PI3K/Akt pathway may enhance the management of carcinoid disease. Synopsis Carcinoid tumor cells were treated with a PI3K inhibitor, LY294002, and Akt1 siRNA to delineate the role of PI3K/Akt signaling in carcinoids. The effects of treatment on cellular proliferation and neuroendocrine marker expression were observed. PMID:19588205

  14. Inhibition of poly(ADP-ribose) polymerase-1 by olaparib (AZD2281) increases the radiosensitivity of a lung tumor xenograft

    PubMed Central

    Senra, Joana M.; Telfer, Brian A.; Cherry, Kim E.; McCrudden, Cian M.; Hirst, David G.; O’Connor, Mark J.; Wedge, Stephen R.; Stratford, Ian J.

    2011-01-01

    Poly(ADP-ribose) polymerase-1 is a critical enzyme in the repair of DNA strand breaks. Inhibition of PARP-1 increases the effectiveness of radiation in killing tumor cells. However, while the mechanism(s) are well understood for these radiosensitizing effects in vitro, the underlying mechanism(s) in vivo are less clear. Nicotinamide, a drug structurally related to the first generation PARP-1 inhibitor, 3-aminobenzamide, reduces tumor hypoxia by preventing transient cessations in tumor blood flow, thus improving tumor oxygenation and sensitivity to radiotherapy. Here we investigate whether olaparib, a potent PARP-1 inhibitor, enhances radiotherapy, not only by inhibiting DNA repair but also by changing tumor vascular haemodynamics in non-small cell lung carcinoma. In irradiated Calu-6 and A549 cells, olaparib enhanced the cytotoxic effects of radiation (SER10=1.5 and 1.3) and DNA double strand breaks persisted for at least 24 h after treatment. Combination treatment of Calu-6 xenografts with olaparib and fractionated radiotherapy caused significant tumor regression (p=0.007) relative to radiotherapy alone. To determine whether this radiosensitisation was due solely to effects on DNA repair we used a dorsal window chamber model to establish the drug/radiation effects on vessel dynamics. Olaparib alone, when given as single or multiple daily doses, or in combination with fractionated radiotherapy, increased the perfusion of tumor blood vessels. Furthermore, an ex vivo assay in phenylephrine pre-constricted arteries confirmed olaparib to have higher vasodilatory properties than nicotinamide. This study suggests that olaparib warrants consideration for further development in combination with radiotherapy in clinical oncology settings such as NSCLC. PMID:21825006

  15. Pu-erh Tea Inhibits Tumor Cell Growth by Down-Regulating Mutant p53

    PubMed Central

    Zhao, Lanjun; Jia, Shuting; Tang, Wenru; Sheng, Jun; Luo, Ying

    2011-01-01

    Pu-erh tea is a kind of fermented tea with the incorporation of microorganisms’ metabolites. Unlike green tea, the chemical characteristics and bioactivities of Pu-erh tea are still not well understood. Using water extracts of Pu-erh tea, we analyzed the tumor cell growth inhibition activities on several genetically engineered mouse tumor cell lines. We found that at the concentration that did not affect wild type mouse embryo fibroblasts (MEFs) growth, Pu-erh tea extracts could inhibit tumor cell growth by down-regulated S phase and cause G1 or G2 arrest. Further study showed that Pu-erh tea extracts down-regulated the expression of mutant p53 in tumor cells at the protein level as well as mRNA level. The same concentration of Pu-erh tea solution did not cause p53 stabilization or activation of its downstream pathways in wild type cells. We also found that Pu-erh tea treatment could slightly down-regulate both HSP70 and HSP90 protein levels in tumor cells. These data revealed the action of Pu-erh tea on tumor cells and provided the possible mechanism for Pu-erh tea action, which explained its selectivity in inhibiting tumor cells without affecting wild type cells. Our data sheds light on the application of Pu-erh tea as an anti-tumor agent with low side effects. PMID:22174618

  16. Pu-erh tea inhibits tumor cell growth by down-regulating mutant p53.

    PubMed

    Zhao, Lanjun; Jia, Shuting; Tang, Wenru; Sheng, Jun; Luo, Ying

    2011-01-01

    Pu-erh tea is a kind of fermented tea with the incorporation of microorganisms' metabolites. Unlike green tea, the chemical characteristics and bioactivities of Pu-erh tea are still not well understood. Using water extracts of Pu-erh tea, we analyzed the tumor cell growth inhibition activities on several genetically engineered mouse tumor cell lines. We found that at the concentration that did not affect wild type mouse embryo fibroblasts (MEFs) growth, Pu-erh tea extracts could inhibit tumor cell growth by down-regulated S phase and cause G1 or G2 arrest. Further study showed that Pu-erh tea extracts down-regulated the expression of mutant p53 in tumor cells at the protein level as well as mRNA level. The same concentration of Pu-erh tea solution did not cause p53 stabilization or activation of its downstream pathways in wild type cells. We also found that Pu-erh tea treatment could slightly down-regulate both HSP70 and HSP90 protein levels in tumor cells. These data revealed the action of Pu-erh tea on tumor cells and provided the possible mechanism for Pu-erh tea action, which explained its selectivity in inhibiting tumor cells without affecting wild type cells. Our data sheds light on the application of Pu-erh tea as an anti-tumor agent with low side effects.

  17. Inhibition of geranylgeranylation mediates sensitivity to CHOP-induced cell death of DLBCL cell lines

    SciTech Connect

    Ageberg, Malin; Rydstroem, Karin; Linden, Ola; Linderoth, Johan; Jerkeman, Mats; Drott, Kristina

    2011-05-01

    Prenylation is a post-translational hydrophobic modification of proteins, important for their membrane localization and biological function. The use of inhibitors of prenylation has proven to be a useful tool in the activation of apoptotic pathways in tumor cell lines. Rab geranylgeranyl transferase (Rab GGT) is responsible for the prenylation of the Rab family. Overexpression of Rab GGTbeta has been identified in CHOP refractory diffuse large B cell lymphoma (DLBCL). Using a cell line-based model for CHOP resistant DLBCL, we show that treatment with simvastatin, which inhibits protein farnesylation and geranylgeranylation, sensitizes DLBCL cells to cytotoxic treatment. Treatment with the farnesyl transferase inhibitor FTI-277 or the geranylgeranyl transferase I inhibitor GGTI-298 indicates that the reduction in cell viability was restricted to inhibition of geranylgeranylation. In addition, treatment with BMS1, a combined inhibitor of farnesyl transferase and Rab GGT, resulted in a high cytostatic effect in WSU-NHL cells, demonstrated by reduced cell viability and decreased proliferation. Co-treatment of BMS1 or GGTI-298 with CHOP showed synergistic effects with regard to markers of apoptosis. We propose that inhibition of protein geranylgeranylation together with conventional cytostatic therapy is a potential novel strategy for treating patients with CHOP refractory DLBCL.

  18. Glycolysis Inhibition Inactivates ABC Transporters to Restore Drug Sensitivity in Malignant Cells

    PubMed Central

    Nakano, Ayako; Tsuji, Daisuke; Miki, Hirokazu; Cui, Qu; Sayed, Salah Mohamed El; Ikegame, Akishige; Oda, Asuka; Amou, Hiroe; Nakamura, Shingen; Harada, Takeshi; Fujii, Shiro; Kagawa, Kumiko; Takeuchi, Kyoko; Sakai, Akira; Ozaki, Shuji; Okano, Kazuma; Nakamura, Takahiro; Itoh, Kohji; Matsumoto, Toshio; Abe, Masahiro

    2011-01-01

    Cancer cells eventually acquire drug resistance largely via the aberrant expression of ATP-binding cassette (ABC) transporters, ATP-dependent efflux pumps. Because cancer cells produce ATP mostly through glycolysis, in the present study we explored the effects of inhibiting glycolysis on the ABC transporter function and drug sensitivity of malignant cells. Inhibition of glycolysis by 3-bromopyruvate (3BrPA) suppressed ATP production in malignant cells, and restored the retention of daunorubicin or mitoxantrone in ABC transporter-expressing, RPMI8226 (ABCG2), KG-1 (ABCB1) and HepG2 cells (ABCB1 and ABCG2). Interestingly, although side population (SP) cells isolated from RPMI8226 cells exhibited higher levels of glycolysis with an increased expression of genes involved in the glycolytic pathway, 3BrPA abolished Hoechst 33342 exclusion in SP cells. 3BrPA also disrupted clonogenic capacity in malignant cell lines including RPMI8226, KG-1, and HepG2. Furthermore, 3BrPA restored cytotoxic effects of daunorubicin and doxorubicin on KG-1 and RPMI8226 cells, and markedly suppressed subcutaneous tumor growth in combination with doxorubicin in RPMI8226-implanted mice. These results collectively suggest that the inhibition of glycolysis is able to overcome drug resistance in ABC transporter-expressing malignant cells through the inactivation of ABC transporters and impairment of SP cells with enhanced glycolysis as well as clonogenic cells. PMID:22073292

  19. Modification of Cyclic NGR Tumor Neovasculature-Homing Motif Sequence to Human Plasminogen Kringle 5 Improves Inhibition of Tumor Growth

    PubMed Central

    Jiang, Weiwei; Jin, Guanghui; Ma, Dingyuan; Wang, Feng; Fu, Tong; Chen, Xiao; Chen, Xiwen; Jia, Kunzhi; Marikar, Faiz M. M. T.; Hua, Zichun

    2012-01-01

    Background Blood vessels in tumors express higher level of aminopeptidase N (APN) than normal tissues. Evidence suggests that the CNGRC motif is an APN ligand which targets tumor vasculature. Increased expression of APN in tumor vascular endothelium, therefore, offers an opportunity for targeted delivery of NGR peptide-linked drugs to tumors. Methods/Principal Findings To determine whether an additional cyclic CNGRC sequence could improve endothelial cell homing and antitumor effect, human plasminogen kringle 5 (hPK5) was modified genetically to introduce a CNGRC motif (NGR-hPK5) and was subsequently expressed in yeast. The biological activity of NGR-hPK5 was assessed and compared with that of wild-type hPK5, in vitro and in vivo. NGR-hPK5 showed more potent antiangiogenic activity than wild-type hPK5: the former had a stronger inhibitory effect on proliferation, migration and cord formation of vascular endothelial cells, and produced a stronger antiangiogenic response in the CAM assay. To evaluate the tumor-targeting ability, both wild-type hPK5 and NGR-hPK5 were 99 mTc-labeled, for tracking biodistribution in the in vivo tumor model. By planar imaging and biodistribution analyses of major organs, NGR-hPK5 was found localized to tumor tissues at a higher level than wild-type hPK5 (approximately 3-fold). Finally, the effects of wild-type hPK5 and NGR-modified hPK5 on tumor growth were investigated in two tumor model systems. NGR modification improved tumor localization and, as a consequence, effectively inhibited the growth of mouse Lewis lung carcinoma (LLC) and human colorectal adenocarcinoma (Colo 205) cells in tumor-bearing mice. Conclusions/Significance These studies indicated that the addition of an APN targeting peptide NGR sequence could improve the ability of hPK5 to inhibit angiogenesis and tumor growth. PMID:22590653

  20. CDC42 inhibition suppresses progression of incipient intestinal tumors

    USDA-ARS?s Scientific Manuscript database

    Mutations in the APC or Beta-catenin genes are well-established initiators of colorectal cancer, yet modifiers that facilitate the survival and progression of nascent tumor cells are not well defined. Using genetic and pharmacologic approaches in mouse colorectal cancer and human colorectal cancer x...

  1. Activated platelets inhibit hepatocellular carcinoma cell differentiation and promote tumor progression via platelet-tumor cell binding

    PubMed Central

    Xu, Jingchao; Li, Bing; Liu, Yue-Jian; Cheng, Cheng; Zhou, Chunyan; Zhao, Yongfu; Liu, Yang

    2016-01-01

    Lack of differentiation in hepatocellular carcinoma (HCC) is associated with increased circulating platelet size. We measured platelet activation and plasma adenosine diphosphate (ADP) levels in HCC patients based on differentiation status. Local platelet accumulation and platelet-hepatoma cell binding were measured using immunohistochemistry (IHC) or flow cytometry. Using a xenograft assay in NON/SCID mice, we tested the effects of the anti-platelet drug clopidogrel on platelet activation, platelet infiltration, platelet-tumor cell binding and tumor cell differentiation. HCC patients with poor differentiation status displayed elevated platelet activation and higher ADP levels. Platelets accumulated within poorly differentiated tissues and localized at hepatoma cell membranes. Platelet-tumor cell binding was existed in carcinoma tissues, largely mediated by P-selectin on platelets. NOD/SCID mice with xenograft tumors also exhibited increased platelet activation and platelet-tumor cell binding. Clopidogrel therapy triggered hepatoma cell differentiation by attenuating platelet activation and platelet-tumor cell binding. TCF4 knockdown promoted HepG-2 cell differentiation and inhibited tumor formation, and TCF4 could be the potential downstream target for clopidogrel therapy. PMID:27542264

  2. Morelloflavone, a biflavonoid, inhibits tumor angiogenesis by targeting Rho GTPases and ERK signaling pathways

    PubMed Central

    Pang, Xiufeng; Yi, Tingfang; Yi, Zhengfang; Cho, Sung Gook; Qu, Weijing; Pinkaew, Decha; Fujise, Ken; Liu, Mingyao

    2009-01-01

    Morelloflavone, a biflavonoid extracted from Garcinia dulcis, has shown anti-oxidative, antiviral, and anti-inflammatory properties. However, the function and the mechanism of this compound in cancer treatment and tumor angiogenesis have not been elucidated to date. In this study, we postulated that morelloflavone might have the ability to inhibit angiogenesis, the pivotal step in tumor growth, invasiveness and metastasis. We demonstrated that morelloflavone could inhibit vascular endothelial growth factor (VEGF)-induced cell proliferation, migration, invasion, and capillary-like tube formation of primary cultured human umbilical endothelial cells (HUVECs) in a dose-dependent manner. Morelloflavone effectively inhibited microvessel sprouting of endothelial cells in the rat aortic ring assay and the formation of new blood microvessels induced by VEGF in the mouse Matrigel plug assay. Furthermore, morelloflavone inhibited tumor growth and tumor angiogenesis of prostate cancer cells (PC-3) in xenograft mouse tumor model in vivo, suggesting that morelloflavone inhibited tumorigenesis by targeting angiogenesis. To understand the underlying mechanism of morelloflavone on the inhibitory effect of tumor growth and angiogenesis, we demonstrated that morelloflavone could inhibit the activation of both RhoA and Rac1 GTPases, but have little effect on the activation of Cdc42 GTPase. Additionally, morelloflavone inhibited the phosphorylation and activation of Raf/MEK/ERK pathway kinases without affecting VEGFR2 activity. Together, our results indicate that morelloflavone exerts anti-angiogenic action by targeting the activation of Rho-GTPases and ERK signaling pathways. These findings are the first to reveal the novel functions of morelloflavone in tumor angiogenesis and its molecular basis for the anticancer action. PMID:19147565

  3. Polychromatic Light (480-3400 nm) Upregulates Sensitivity of Tumor Cells to Lysis by Natural Killers.

    PubMed

    Knyazev, Nickolay A; Samoilova, Kira A; Abrahamse, Heidi; Filatova, Natalia A

    2016-09-01

    This study evaluates the participation of immunological mechanisms of downregulation of murine hepatoma cells MH22a after direct exposure to polychromatic polarized light. Previous studies have shown that exposure to a combination of visible (VIS) and infrared (IR) light leads to decreased tumorigenicity of the murine hepatoma cells MH22a, which correlated with an increase in the amount of cells with reorganized cytoskeleton in the submembrane region. The mechanism of tumor inhibition and elimination has not been determined. Polychromatic light (480-3400 nm) has been used at doses of 4.8 and 9.6 J/cm(2) to determine the sensitivity of murine MH22a cells and human erythroleukemia cells K562 exposed to this light, to lysis by effector cells of innate immunity (NK cells), and enhancement of the glycocalyx of the studied tumor cells. This was determined using flow cytometry, the H(3)-uridine cytotoxic test followed by spectrophotometry. VIS-IR light increases the sensitivity of MH-22a cells at a dose 4.8 J/cm(2) and K562 cells at 9.6 J/cm(2). The enhancement of sensitivity of tumor cells to NK lysis changed their ability to absorb alcian blue, reflecting a change in the expression of the glycocalyx. Increasing the sensitivity of the murine tumor cells MH22a and human K562 irradiated VIS-IR light correlated with a change in the expression of their glycocalyx. The results of the present study demonstrate that the reduction of tumorigenicity of irradiated tumor cells is due to their sensitivity to lysis by NK cells of the immune system.

  4. Rat Hormone Sensitive Lipase Inhibition by Cyclipostins and Their Analogs

    PubMed Central

    Vasilieva, Elena; Dutta, Supratik; Malla, Raj K.; Martin, Benjamin P.; Spilling, Christopher D.; Dupureur, Cynthia M.

    2015-01-01

    Cyclipostins are bicyclic lipophilic phosphate natural products. We report here that synthesized individual diastereomers of cyclipostins P and R have nanomolar IC50s toward hormone sensitive lipase (HSL). The less potent diastereomers of these compounds have 10-fold weaker IC50s. The monocyclic phosphate analog of cyclipostin P is nearly as potent as the bicyclic natural product. Bicyclic phosphonate analogs of both cyclipostins exhibit IC50s similar to those of the weaker diastereomer phosphates (about 400 nM). The monocyclic phosphonate analog of cyclipostin P has similar potency. A series of monocyclic phosphonate analogs in which a hydrophobic tail extends from the lactone side of the ring are considerably poorer inhibitors, with IC50s around 50 μM. Finally cyclophostin, a related natural product inhibitor of acetylcholinesterase (AChE) that lacks the hydrocarbon tail of cyclipostins, is not active against HSL. These results indicate a critical SAR for these compounds, the hydrophobic tail. The smaller lactone ring is not critical to activity, a similarity shared with cyclophostin and AChE. The HSL kinetics of inhibition for the cyclipostin P trans diastereomer were examined in detail. The reaction is irreversible with a KI of 40 nM and a rate constant for inactivation of 0.2 min−1. These results are similar to those observed for cyclophostin and AChE. PMID:25678014

  5. Dentate total molecular layer interneurons mediate cannabinoid-sensitive inhibition.

    PubMed

    Yu, Jiandong; Swietek, Bogumila; Proddutur, Archana; Santhakumar, Vijayalakshmi

    2015-08-01

    Activity of the dentate gyrus, which gates information flow to the hippocampus, is under tight inhibitory regulation by interneurons with distinctive axonal projections, intrinsic and synaptic characteristics and neurochemical identities. Total molecular layer cells (TML-Cs), a class of morphologically distinct GABAergic neurons with axonal projections across the molecular layer, are among the most frequent interneuronal type in the dentate subgranular region. However, little is known about their synaptic and neurochemical properties. We demonstrate that synapses from morphologically identified TML-Cs to dentate interneurons are characterized by low release probability, facilitating short-term dynamics and asynchronous release. TML-Cs consistently show somatic and axonal labeling for the cannabinoid receptor type 1 (CB1 R) yet fail to express cholecystokinin (CCK) indicating their distinctive neurochemical identity. In paired recordings, the release probability at synapses between TML-Cs was increased by the CB1 R antagonist AM251, demonstrating baseline endocannabinoid regulation of TML-C synapses. Apart from defining the synaptic and neurochemical features of TML-Cs, our findings reveal the morphological identity of a class of dentate CB1 R-positive neurons that do not express CCK. Our findings indicate that TML-Cs can mediate cannabinoid sensitive feed-forward and feedback inhibition of dentate perforant path inputs.

  6. CA-1H, a novel oxazole bearing analogue of combretastatin A-4, disrupts the tumor vasculatures and inhibits the tumor growth via inhibiting tubulin polymerization.

    PubMed

    Han, Fuguo; Wang, Peng; Zhang, Wei; Li, Jing; Zhang, Qun; Qi, Xin; Liu, Ming

    2016-05-01

    Vascular disrupting agents destroy established tumor vasculatures selectively, and have achieved encouraging antitumor activity in both pre-clinical and clinical trials. In the present study, we reported the vascular disruption and antitumor effects of CA-1H and its prodrug CA-1HP, oxazole bearing analogues of combretastatin A-4 (CA4). CA-1H was a tighter binder of tubulin than CA4 with the same binding site to chochcine and CA4, and inhibited tubulin polymerization both in cell free system and in human umbilical vein endothelial cells (HUVECs). Furthermore, CA-1H significantly disrupted the microtubulin skeleton in proliferating HUVECs rather than the quiescent ones, damaged the HUVECs-preformed tubes markedly, and lead to necrosis in tumor tissues in NCI-H1975 xenograft mice. Continuous administration for 19 days, CA-1HP could inhibit the NCI-H1975 xenograft tumor growth significantly without obvious weight loss and normal tissue damage, in addition, CA-1HP also inhibited the tumor growth in H22 hepatocellular carcinoma bearing mice; and combination CA-1HP with cisplatin showed more potent antitumor activity than used alone. Taken together, our present investigation suggested that CA-1H was a potential vascular disrupting agent for further development of antitumor drugs.

  7. SHORT PEDF-DERIVED PEPTIDE INHIBITS ANGIOGENESIS AND TUMOR GROWTH

    PubMed Central

    Mirochnik, Yelena; Aurora, Arin; Schulze-Hoepfner, Frank T.; Deabes, Ahmed; Shifrin, Victor; Beckmann, Richard; Polsky, Charles; Volpert, Olga V.

    2010-01-01

    Purpose Pigment epithelial-derived factor (PEDF) is a potent angiogenesis inhibitor with multiple other functions, some of which enhance tumor growth. Our previous studies mapped PEDF anti-angiogenic and pro-survival activities to distinct epitopes. This study was aimed to determine the minimal fragment of PEDF, which maintains anti-angiogenic and anti-tumor efficacy. Experimental Design We analyzed antigenicity, hydrophilicity, and charge distribution of the angioinhibitory epitope (the 34-mer) and designed three peptides covering its C-terminus, P14, P18 and P23. We analyzed their ability to block endothelial cell (EC) chemotaxis and induce apoptosis in vitro and their anti-angiogenic activity in vivo. The selected peptide was tested for the anti-tumor activity against mildly aggressive xenografted prostate carcinoma and highly aggressive renal cell carcinoma. To verify that P18 acts in the same manner as PEDF, we used immunohistochemistry to measure PEDF targets, VEGFR2 and CD95L expression in P18-treated vasculature. Results P14 and P18 blocked endothelial cell chemotaxis; P18 and P23 induced apoptosis. P18 showed the highest IC50 and blocked angiogenesis in vivo: P23 was inactive and P14 was pro-angiogenic. P18 increased the production of CD95L and reduced the expression of VEGFR-2 by the endothelial cells in vivo. In tumor studies, P18 was more effective in blocking the angiogenesis and growth of the prostate cancer then parental 34-mer; in the renal cell carcinoma P18 strongly decreased angiogenesis and halted the progression of established tumors. Conclusions P18 is a novel and potent anti-angiogenic biotherapeutic agent, which has potential to be developed for the treatment of prostate and renal cancer. PMID:19223494

  8. Se-methylselenocysteine sensitizes hypoxic tumor cells to irinotecan by targeting hypoxia-inducible factor 1α

    PubMed Central

    Chintala, Sreenivasulu; Tóth, Károly; Cao, Shousong; Durrani, Farukh A.; Vaughan, Mary M.; Jensen, Randy L.; Rustum, Youcef M.

    2010-01-01

    Purpose Hypoxic tumor cells overexpressing hypoxia-inducible factor 1alpha (HIF-1α) are generally resistant to chemo/radiotherapy. We have reported that Se-methylselenocysteine (MSC) therapeutically enhances the efficacy and selectivity of irinotecan against human tumor xenografts. The aim of this study was to delineate the mechanism responsible for the observed efficacy targeting on HIF-1α and its transcriptionally regulated genes VEGF and CAIX. Methods We investigated the mechanism of HIF-1α inhibition by MSC and its critical role in the therapeutic outcome by generating HIF-1α stable knockdown (KD) human head and neck squamous cell carcinoma, FaDu by transfecting HIF-1α short hairpin RNA. Results While cytotoxic efficacy in combination with methylselenic acid (MSA) with SN-38 (active metabolites of MSC and irinotecan) could not be confirmed in vitro against normoxic tumor cells, the hypoxic tumor cells were more sensitive to the combination. Reduction in HIF-1α either by MSA or shRNA knockdown resulted in significant increase in cytotoxicity of SN38 in vitro against hypoxic, but not the normoxic tumor cells. Similarly, in vivo, either MSC in combination with irinotecan treatment of parental xenografts or HIF-1α KD tumors treated with irinotecan alone resulted in comparable therapeutic response and increase in the long-term survival of mice bearing FaDu xenografts. Conclusions Our results show that HIF-1α is a critical target for MSC and its inhibition was associated with enhanced antitumor activity of irinotecan. Inhibition of HIF-1α appeared to be mediated through stabilization of PHD2, 3 and downregulation of ROS by MSC. Thus, our findings support the development of MSC as a HIF-1α inhibitor in combination chemotherapy. PMID:20066420

  9. Direct tumor recognition by a human CD4+ T-cell subset potently mediates tumor growth inhibition and orchestrates anti-tumor immune responses

    PubMed Central

    Matsuzaki, Junko; Tsuji, Takemasa; Luescher, Immanuel F.; Shiku, Hiroshi; Mineno, Junichi; Okamoto, Sachiko; Old, Lloyd J.; Shrikant, Protul; Gnjatic, Sacha; Odunsi, Kunle

    2015-01-01

    Tumor antigen-specific CD4+ T cells generally orchestrate and regulate immune cells to provide immune surveillance against malignancy. However, activation of antigen-specific CD4+ T cells is restricted at local tumor sites where antigen-presenting cells (APCs) are frequently dysfunctional, which can cause rapid exhaustion of anti-tumor immune responses. Herein, we characterize anti-tumor effects of a unique human CD4+ helper T-cell subset that directly recognizes the cytoplasmic tumor antigen, NY-ESO-1, presented by MHC class II on cancer cells. Upon direct recognition of cancer cells, tumor-recognizing CD4+ T cells (TR-CD4) potently induced IFN-γ-dependent growth arrest in cancer cells. In addition, direct recognition of cancer cells triggers TR-CD4 to provide help to NY-ESO-1-specific CD8+ T cells by enhancing cytotoxic activity, and improving viability and proliferation in the absence of APCs. Notably, the TR-CD4 either alone or in collaboration with CD8+ T cells significantly inhibited tumor growth in vivo in a xenograft model. Finally, retroviral gene-engineering with T cell receptor (TCR) derived from TR-CD4 produced large numbers of functional TR-CD4. These observations provide mechanistic insights into the role of TR-CD4 in tumor immunity, and suggest that approaches to utilize TR-CD4 will augment anti-tumor immune responses for durable therapeutic efficacy in cancer patients. PMID:26447332

  10. Tumor-Associated Lymphatic Vessels Upregulate PDL1 to Inhibit T-Cell Activation.

    PubMed

    Dieterich, Lothar C; Ikenberg, Kristian; Cetintas, Timur; Kapaklikaya, Kübra; Hutmacher, Cornelia; Detmar, Michael

    2017-01-01

    Tumor-associated lymphatic vessels (LVs) play multiple roles during tumor progression, including promotion of metastasis and regulation of antitumor immune responses by delivering antigen from the tumor bed to draining lymph nodes (LNs). Under steady-state conditions, LN resident lymphatic endothelial cells (LECs) have been found to maintain peripheral tolerance by directly inhibiting autoreactive T-cells. Similarly, tumor-associated lymphatic endothelium has been suggested to reduce antitumor T-cell responses, but the mechanisms that mediate this effect have not been clarified. Using two distinct experimental tumor models, we found that tumor-associated LVs gain expression of the T-cell inhibitory molecule PDL1, similar to LN resident LECs, whereas tumor-associated blood vessels downregulate PDL1. The observed lymphatic upregulation of PDL1 was likely due to IFN-g released by stromal cells in the tumor microenvironment. Furthermore, we found that blocking PDL1 results in increased T-cell stimulation by antigen-presenting LECs in vitro. Taken together, our data suggest that peripheral, tumor-associated lymphatic endothelium contributes to T-cell inhibition, by a mechanism similar to peripheral tolerance maintenance described for LN resident LECs. These findings may have clinical implications for cancer therapy, as lymphatic expression of PDL1 could represent a new biomarker to select patients for immunotherapy with PD1 or PDL1 inhibitors.

  11. Tumor-Associated Lymphatic Vessels Upregulate PDL1 to Inhibit T-Cell Activation

    PubMed Central

    Dieterich, Lothar C.; Ikenberg, Kristian; Cetintas, Timur; Kapaklikaya, Kübra; Hutmacher, Cornelia; Detmar, Michael

    2017-01-01

    Tumor-associated lymphatic vessels (LVs) play multiple roles during tumor progression, including promotion of metastasis and regulation of antitumor immune responses by delivering antigen from the tumor bed to draining lymph nodes (LNs). Under steady-state conditions, LN resident lymphatic endothelial cells (LECs) have been found to maintain peripheral tolerance by directly inhibiting autoreactive T-cells. Similarly, tumor-associated lymphatic endothelium has been suggested to reduce antitumor T-cell responses, but the mechanisms that mediate this effect have not been clarified. Using two distinct experimental tumor models, we found that tumor-associated LVs gain expression of the T-cell inhibitory molecule PDL1, similar to LN resident LECs, whereas tumor-associated blood vessels downregulate PDL1. The observed lymphatic upregulation of PDL1 was likely due to IFN-g released by stromal cells in the tumor microenvironment. Furthermore, we found that blocking PDL1 results in increased T-cell stimulation by antigen-presenting LECs in vitro. Taken together, our data suggest that peripheral, tumor-associated lymphatic endothelium contributes to T-cell inhibition, by a mechanism similar to peripheral tolerance maintenance described for LN resident LECs. These findings may have clinical implications for cancer therapy, as lymphatic expression of PDL1 could represent a new biomarker to select patients for immunotherapy with PD1 or PDL1 inhibitors. PMID:28217128

  12. MET inhibition in tumor cells by PHA665752 impairs homologous recombination repair of DNA double strand breaks.

    PubMed

    Medová, Michaela; Aebersold, Daniel M; Zimmer, Yitzhak

    2012-02-01

    Abnormal activation of cellular DNA repair pathways by deregulated signaling of receptor tyrosine kinase systems has broad implications for both cancer biology and treatment. Recent studies suggest a potential link between DNA repair and aberrant activation of the hepatocyte growth factor receptor Mesenchymal-Epithelial Transition (MET), an oncogene that is overexpressed in numerous types of human tumors and considered a prime target in clinical oncology. Using the homologous recombination (HR) direct-repeat direct-repeat green fluorescent protein ((DR)-GFP) system, we show that MET inhibition in tumor cells with deregulated MET activity by the small molecule PHA665752 significantly impairs in a dose-dependent manner HR. Using cells that express MET-mutated variants that respond differentially to PHA665752, we confirm that the observed HR inhibition is indeed MET-dependent. Furthermore, our data also suggest that decline in HR-dependent DNA repair activity is not a secondary effect due to cell cycle alterations caused by PHA665752. Mechanistically, we show that MET inhibition affects the formation of the RAD51-BRCA2 complex, which is crucial for error-free HR repair of double strand DNA lesions, presumably via downregulation and impaired translocation of RAD51 into the nucleus. Taken together, these findings assist to further support the role of MET in the cellular DNA damage response and highlight the potential future benefit of MET inhibitors for the sensitization of tumor cells to DNA damaging agents.

  13. Hsp90 inhibitor 17-AAG inhibits progression of LuCaP35 xenograft prostate tumors to castration resistance

    PubMed Central

    O’Malley, Katherine J.; Langmann, Gabrielle; Ai, Junkui; Ramos-Garcia, Raquel; Vessella, Robert L.; Wang, Zhou

    2011-01-01

    BACKGROUND Advanced prostate cancer is currently treated with androgen deprivation therapy (ADT). ADT initially results in tumor regression, however, all patients eventually relapse with castration-resistant prostate cancer. New approaches to delay the progression of prostate cancer to castration resistance are in desperate need. This study addresses whether targeting HSP90 regulation of androgen receptor (AR) can inhibit prostate cancer progression to castration resistance. METHODS The HSP90 inhibitor 17-AAG was injected intraperitoneally into nude mice bearing LuCaP35 xenograft tumors to determine the effect of HSP90 inhibition on prostate cancer progression to castration resistance and host survival. RESULTS Administration of 17-AAG maintained androgen-sensitivity, delayed the progression of LuCaP35 xenograft tumors to castration resistance and prolonged the survival of host. In addition, 17-AAG prevented nuclear localization of endogenous AR in LuCaP35 xenograft tumors in castrated nude mice. CONCLUSIONS Targeting Hsp90 or the mechanism by which HSP90 regulates androgen-independent AR nuclear localization and activation may lead to new approaches to prevent and/or treat castration-resistant prostate cancer. PMID:22161776

  14. DT-13 inhibits cancer cell migration by regulating NMIIA indirectly in the tumor microenvironment.

    PubMed

    Du, Hongzhi; Huang, Yue; Hou, Xiaoyin; Yu, Xiaowen; Lin, Sensen; Wei, Xiaohui; Li, Ruiming; Khan, Ghulam Jilany; Yuan, Shengtao; Sun, Li

    2016-08-01

    Tumor metastasis is one of the main causes of mortality among patients with malignant tumors. Previous studies concerning tumor metastasis have merely focused on the cancer cells in the tumor. However, an increasing number of studies show that the tumor microenvironment plays a vital role in the progression of cancer, particularly in tumor metastasis. Since fibroblasts and adipocytes are two of the most representative mesenchymal cells in the tumor microenvironment, we established a hypoxia-induced cancer-associated fibroblast (CAF) model and a chemically induced adipocyte model to reveal the effect of the microenvironment on cancer development. In these models, the conditioned medium from the tumor microenvironment was found to significantly promote the migration of human lung cancer cell line 95D and regulate the expression of non-muscle myosin IIA (NMIIA), which is consistent with results in the published literature. Then, we confirmed the hypothesis that the tumor microenvironment can regulate NMIIA in cancer cells and facilitate migration by using the non-muscle myosin II inhibitor, blebbistatin. Thus, this is the first report that the tumor microenvironment can promote cancer cell migration by regulating the expression of NMIIA. Our present data also indicated that DT-13, the saponin monomer 13 of dwarf lilyturf tuber, inhibited cancer cell migration in the tumor microenvironment model. Further results showed that DT-13 exhibited anti-migratory effects by inhibiting the c-raf/ERK1/2 signaling pathway. Consequently, our research confirmed that DT-13 significantly inhibited 95D cell migration in vitro, indicating the potential anti-metastatic effect of DT-13 on lung cancer and the scientific basis for drug development.

  15. In vivo inhibition of endogenous brain tumors through systemic interference of Hedgehog signaling in mice.

    PubMed

    Sanchez, Pilar; Ruiz i Altaba, Ariel

    2005-02-01

    The full spectrum of developmental potential includes normal as well as abnormal and disease states. We therefore subscribe to the idea that tumors derive from the operation of paradevelopmental programs that yield consistent and recognizable morphologies. Work in frogs and mice shows that Hedgehog (Hh)-Gli signaling controls stem cell lineages and that its deregulation leads to tumor formation. Moreover, human tumor cells require sustained Hh-Gli signaling for proliferation as cyclopamine, an alkaloid of the lily Veratrum californicum that blocks the Hh pathway, inhibits the growth of different tumor cells in vitro as well as in subcutaneous xenografts. However, the evidence that systemic treatment is an effective anti-cancer therapy is missing. Here we have used Ptc1(+/-); p53(-/-) mice which develop medulloblastoma to test the ability of cyclopamine to inhibit endogenous tumor growth in vivo after tumor initiation through intraperitoneal delivery, which avoids the brain damage associated with direct injection. We find that systemic cyclopamine administration improves the health of Ptc1(+/-);p53(-/-) animals. Analyses of the cerebella of cyclopamine-treated animals show a severe reduction in tumor size and a large decrease in the number of Ptc1-expressing cells, as a readout of cells with an active Hu-Gli pathway, as well as an impairment of their proliferative capacity, always in comparison with vehicle treated mice. Our data demonstrate that systemic treatment with cyclopamine inhibits tumor growth in the brain supporting its therapeutical value for human HH-dependent tumors. They also demonstrate that even the complete loss of the well-known tumor suppressor p53 does not render the tumor independent of Hh pathway function.

  16. Inhibition of brain tumor cell proliferation by alternating electric fields

    SciTech Connect

    Jeong, Hyesun; Oh, Seung-ick; Hong, Sunghoi E-mail: radioyoon@korea.ac.kr; Sung, Jiwon; Jeong, Seonghoon; Yoon, Myonggeun E-mail: radioyoon@korea.ac.kr; Koh, Eui Kwan

    2014-11-17

    This study was designed to investigate the mechanism by which electric fields affect cell function, and to determine the optimal conditions for electric field inhibition of cancer cell proliferation. Low-intensity (<2 V/cm) and intermediate-frequency (100–300 kHz) alternating electric fields were applied to glioblastoma cell lines. These electric fields inhibited cell proliferation by inducing cell cycle arrest and abnormal mitosis due to the malformation of microtubules. These effects were significantly dependent on the intensity and frequency of applied electric fields.

  17. Numerical sensitivity modeling for the detection of skin tumors by using tetrapolar probe.

    PubMed

    Ramos, Airton; Bertemes-Filho, Pedro

    2011-12-01

    The measurement of electrical impedance of skin using surface electrodes permits the assessment of changes in local properties of the skin and can be used in the detection of tumors. The sensitivity of this technique depends mainly on the geometry of the probe and the size of the tumor. In this article, the impedance method was used to estimate the sensitivity of a tetrapolar probe in detecting small regions of increased conductivity in a stratified model of human skin. The impedance method was used to model the potential distribution using fasorial analysis to solve the node equations of the equivalent circuit. Interpolation was applied to reduce discretization error. The skin was modeled as a three-layer structure with different conductivity and permittivity obtained from the literature. A tumor was modeled as a small volume with admittivity four times higher than the normal tissue. Sensitivity calculation was made as a function of electrode diameter and separation, tumor size, and excitation frequency. The simulations indicated that by inserting a one square millimeter tumor in the epidermis, the load impedance to the current source varies about 1% while the transfer impedance varied 8%. The sensitivity also increases nonlinearly with increasing tumor area and thickness. Additionally, it was found that the sensitivity of the transfer impedance has a maximum value when the electrodes are separated by 1.8 mm. The results show that transfer impedance measurements of the skin may detect small skin tumors with a reasonable sensitivity by using an appropriate tetrapolar probe.

  18. Inhibition of hypoxia-inducible factors limits tumor progression in a mouse model of colorectal cancer

    PubMed Central

    Simon, M.Celeste

    2014-01-01

    Hypoxia-inducible factors (HIFs) accumulate in both neoplastic and inflammatory cells within the tumor microenvironment and impact the progression of a variety of diseases, including colorectal cancer. Pharmacological HIF inhibition represents a novel therapeutic strategy for cancer treatment. We show here that acriflavine (ACF), a naturally occurring compound known to repress HIF transcriptional activity, halts the progression of an autochthonous model of established colitis-associated colon cancer (CAC) in immunocompetent mice. ACF treatment resulted in decreased tumor number, size and advancement (based on histopathological scoring) of CAC. Moreover, ACF treatment corresponded with decreased macrophage infiltration and vascularity in colorectal tumors. Importantly, ACF treatment inhibited the hypoxic induction of M-CSFR, as well as the expression of the angiogenic factor (vascular endothelial growth factor), a canonical HIF target, with little to no impact on the Nuclear factor-kappa B pathway in bone marrow-derived macrophages. These effects probably explain the observed in vivo phenotypes. Finally, an allograft tumor model further confirmed that ACF treatment inhibits tumor growth through HIF-dependent mechanisms. These results suggest pharmacological HIF inhibition in multiple cell types, including epithelial and innate immune cells, significantly limits tumor growth and progression. PMID:24408928

  19. Inhibition of tumor-stromal interaction through HGF/Met signaling by valproic acid

    SciTech Connect

    Matsumoto, Yohsuke; Motoki, Takahiro; Kubota, Satoshi; Takigawa, Masaharu; Tsubouchi, Hirohito; Gohda, Eiichi

    2008-02-01

    Hepatocyte growth factor (HGF), which is produced by surrounding stromal cells, including fibroblasts and endothelial cells, has been shown to be a significant factor responsible for cancer cell invasion mediated by tumor-stromal interactions. We found in this study that the anti-tumor agent valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, strongly inhibited tumor-stromal interaction. VPA inhibited HGF production in fibroblasts induced by epidermal growth factor (EGF), platelet-derived growth factor, basic fibroblast growth factor, phorbol 12-myristate 13-acetate (PMA) and prostaglandin E{sub 2} without any appreciable cytotoxic effect. Other HDAC inhibitors, including butyric acid and trichostatin A (TSA), showed similar inhibitory effects on HGF production stimulated by various inducers. Up-regulations of HGF gene expression induced by PMA and EGF were also suppressed by VPA and TSA. Furthermore, VPA significantly inhibited HGF-induced invasion of HepG2 hepatocellular carcinoma cells. VPA, however, did not affect the increases in phosphorylation of MAPK and Akt in HGF-treated HepG2 cells. These results demonstrated that VPA inhibited two critical processes of tumor-stromal interaction, induction of fibroblastic HGF production and HGF-induced invasion of HepG2 cells, and suggest that those activities serve for other anti-tumor mechanisms of VPA besides causing proliferation arrest, differentiation, and/or apoptosis of tumor cells.

  20. Stiffness changes of tumor HEp2 cells correlates with the inhibition and release of TRAIL-induced apoptosis pathways.

    PubMed

    Targosz-Korecka, Marta; Biedron, Rafal; Szczygiel, Agnieszka Maria; Brzezinka, Grzegorz; Szczerbinski, Jacek; Zuk, Anna

    2012-05-01

    Tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) is a promising apoptotic agent that can selectively act on tumor cells. However, some cancer cells are resistant to TRAIL mediated apoptosis. In specific type of cells, sensitization by chemotherapeutic drugs may overcome the resistance to TRAIL induced apoptosis. In this work, atomic force microscopy (AFM) nanoindentation spectroscopy combined with fluorescence methods were used to investigate the biomechanical aspects of the resistance and unblocking of apoptosis in larynx carcinoma HEp2 cells treated with TRAIL. It is shown that there is a direct correlation between the increase in mechanical cell stiffness and the inhibition of apoptosis induced by TRAIL in HEp2 cells. Conversely, unblocking of apoptosis by sensitization of HEp2 cells with a chemotherapeutic drug Actinomycin D is related to the depolymerization of F-actin and to the decrease in the cell stiffness. Both effects, that is, changes in the mechanical stiffness of the cell and the inhibition of apoptotic pathway, are closely related to the Bcl-2 activity. Most probably, the depolymerization of F-actin results from downregulation of Rho protein, which in turn is accompanied by a lower activity of Bcl-2 and in consequence releases the intrinsic apoptotic channel. The presented results reveal a promising application of nanoindentation spectroscopy with an AFM tip as a novel tool for monitoring the processes of apoptosis inhibition. Copyright © 2012 John Wiley & Sons, Ltd.

  1. PTEN inhibits PREX2-catalyzed activation of RAC1 to restrain tumor cell invasion.

    PubMed

    Mense, Sarah M; Barrows, Douglas; Hodakoski, Cindy; Steinbach, Nicole; Schoenfeld, David; Su, William; Hopkins, Benjamin D; Su, Tao; Fine, Barry; Hibshoosh, Hanina; Parsons, Ramon

    2015-03-31

    The tumor suppressor PTEN restrains cell migration and invasion by a mechanism that is independent of inhibition of the PI3K pathway and decreased activation of the kinase AKT. PREX2, a widely distributed GEF that activates the GTPase RAC1, binds to and inhibits PTEN. We used mouse embryonic fibroblasts and breast cancer cell lines to show that PTEN suppresses cell migration and invasion by blocking PREX2 activity. In addition to metabolizing the phosphoinositide PIP₃, PTEN inhibited PREX2-induced invasion by a mechanism that required the tail domain of PTEN, but not its lipid phosphatase activity. Fluorescent nucleotide exchange assays revealed that PTEN inhibited the GEF activity of PREX2 toward RAC1. PREX2 is a frequently mutated GEF in cancer, and examination of human tumor data showed that PREX2 mutation was associated with high PTEN expression. Therefore, we tested whether cancer-derived somatic PREX2 mutants, which accelerate tumor formation of immortalized melanocytes, were inhibited by PTEN. The three stably expressed, somatic PREX2 cancer mutants that we tested were resistant to PTEN-mediated inhibition of invasion but retained the ability to inhibit the lipid phosphatase activity of PTEN. In vitro analysis showed that PTEN did not block the GEF activity of two PREX2 cancer mutants and had a reduced binding affinity for the third. Thus, PTEN antagonized migration and invasion by restraining PREX2 GEF activity, and PREX2 mutants are likely selected in cancer to escape PTEN-mediated inhibition of invasion.

  2. Enhancer of zeste homolog 2 silencing inhibits tumor growth and lung metastasis in osteosarcoma.

    PubMed

    Lv, Yang-Fan; Yan, Guang-Ning; Meng, Gang; Zhang, Xi; Guo, Qiao-Nan

    2015-08-12

    The enhancer of zeste homolog 2 (EZH2) methyltransferase is the catalytic subunit of polycomb repressive complex 2 (PRC2), which acts as a transcription repressor via the trimethylation of lysine 27 of histone 3 (H3K27me3). EZH2 has been recognised as an oncogene in several types of tumors; however, its role in osteosarcoma has not been fully elucidated. Herein, we show that EZH2 silencing inhibits tumor growth and lung metastasis in osteosarcoma by facilitating re-expression of the imprinting gene tumor-suppressing STF cDNA 3 (TSSC3). Our previous study showed that TSSC3 acts as a tumor suppressor in osteosarcoma. In this study, we found that EZH2 was abnormally elevated in osteosarcoma, and its overexpression was associated with poor prognosis in osteosarcoma. Silencing of EZH2 resulted in tumor growth inhibition, apoptosis and chemosensitivity enhancement. Moreover, suppression of EZH2 markedly inhibited tumor growth and lung metastasis in vivo. Furthermore, EZH2 knockdown facilitated the re-expression of TSSC3 by reducing H3K27me3 in the promoter region. Cotransfection with siEZH2 and siTSSC3 could partially reverse the ability of siEZH2 alone. We have demonstrated that EZH2 plays a crucial role in tumor growth and distant metastasis in osteosarcoma; its oncogenic role is related to its regulation of the expression of TSSC3.

  3. Enhancer of zeste homolog 2 silencing inhibits tumor growth and lung metastasis in osteosarcoma

    PubMed Central

    Lv, Yang-Fan; Yan, Guang-Ning; Meng, Gang; Zhang, Xi; Guo, Qiao-Nan

    2015-01-01

    The enhancer of zeste homolog 2 (EZH2) methyltransferase is the catalytic subunit of polycomb repressive complex 2 (PRC2), which acts as a transcription repressor via the trimethylation of lysine 27 of histone 3 (H3K27me3). EZH2 has been recognised as an oncogene in several types of tumors; however, its role in osteosarcoma has not been fully elucidated. Herein, we show that EZH2 silencing inhibits tumor growth and lung metastasis in osteosarcoma by facilitating re-expression of the imprinting gene tumor-suppressing STF cDNA 3 (TSSC3). Our previous study showed that TSSC3 acts as a tumor suppressor in osteosarcoma. In this study, we found that EZH2 was abnormally elevated in osteosarcoma, and its overexpression was associated with poor prognosis in osteosarcoma. Silencing of EZH2 resulted in tumor growth inhibition, apoptosis and chemosensitivity enhancement. Moreover, suppression of EZH2 markedly inhibited tumor growth and lung metastasis in vivo. Furthermore, EZH2 knockdown facilitated the re-expression of TSSC3 by reducing H3K27me3 in the promoter region. Cotransfection with siEZH2 and siTSSC3 could partially reverse the ability of siEZH2 alone. We have demonstrated that EZH2 plays a crucial role in tumor growth and distant metastasis in osteosarcoma; its oncogenic role is related to its regulation of the expression of TSSC3. PMID:26265454

  4. Patrinia scabiosaefolia inhibits colorectal cancer growth through suppression of tumor angiogenesis.

    PubMed

    Chen, Liwu; Liu, Liya; Ye, Ling; Shen, Aling; Chen, Youqin; Sferra, Thomas J; Peng, Jun

    2013-09-01

    Angiogenesis is an essential process for tumor development and metastasis, therefore inhibition of tumor angiogenesis has become a promising strategy for anticancer treatments. Patrinia scabiosaefolia, a well-known Oriental folk medicine, has been shown to be effective in the clinical treatment of gastrointestinal cancers. However, the precise mechanism of its tumoricidal activity remains largely unknown. Using a colorectal cancer (CRC) mouse xenograft model, the human colon carcinoma cell line HT-29 and human umbilical vein endothelial cells (HUVECs), in the present study we evaluated the effects of an ethanol extract of Patrinia scabiosaefolia (EEPS) on tumor angiogenesis in vivo and in vitro, and investigated the underlying molecular mechanisms. We found that EEPS treatment significantly reduced the tumor volume in CRC mice and decreased the intratumoral microvessel density in tumor tissues. In addition, EEPS inhibited several key processes of angiogenesis, including the proliferation, migration and tube formation of HUVECs. Moreover, EEPS treatment suppressed the expression of VEGF-A in CRC tumors and HT-29 cells. Collectively, our data suggest that Patrinia scabiosaefolia inhibits CRC growth likely via suppression of tumor angiogenesis.

  5. Inhibition of homologous recombination repair in irradiated tumor cells pretreated with Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin

    SciTech Connect

    Noguchi, Miho; Yu, Dong; Hirayama, Ryoichi; Ninomiya, Yasuharu; Sekine, Emiko; Kubota, Nobuo; Ando, Koichi; Okayasu, Ryuichi . E-mail: rokayasu@nirs.go.jp

    2006-12-22

    In order to investigate the mechanism of radio-sensitization by an Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG), we studied repair of DNA double strand breaks (DSBs) in irradiated human cells pre-treated with 17-AAG. DSBs are thought to be the critical target for radiation-induced cell death. Two human tumor cell lines DU145 and SQ-5 which showed clear radio-sensitization by 17-AAG revealed a significant inhibition of DSB repair, while normal human cells which did not show radio-sensitization by the drug indicated no change in the DSB repair kinetics with 17-AAG. We further demonstrated that BRCA2 was a novel client protein for Hsp90, and 17-AAG caused the degradation of BRCA2 and in turn altered the behavior of Rad51, a critical protein for homologous recombination (HR) pathway of DSB repair. Our data demonstrate for the first time that 17-AAG inhibits the HR repair process and could provide a new therapeutic strategy to selectively result in higher tumor cell killing.

  6. Enhanced antitumor reactivity of tumor-sensitized T cells by interferon alfa

    SciTech Connect

    Vander Woude, D.L.; Wagner, P.D.; Shu, S.; Chang, A.E. )

    1991-03-01

    Tumor-draining lymph node cells from mice bearing the methylcholanthrene-induced MCA 106 tumors can be sensitized in vitro to acquire antitumor reactivity. We examined the effect of interferon alfa on the function of cells that underwent in vitro sensitization in adoptive immunotherapy. Interferon alfa increased the antitumor reactivity of in vitro sensitized cells in the treatment of MCA 106 pulmonary metastases. This effect was evident in irradiated mice, indicating that a host response to the interferon alfa was not required. Interferon alfa treatment increased class I major histocompatibility complex antigen expression on tumor cells and increased their susceptibility to lysis by in vitro sensitized cells. These results suggest that interferon alfa enhancement of adoptive immunotherapy was mediated by its effect on tumor cells. Interferon alfa may be a useful adjunct to the adoptive immunotherapy of human cancer.

  7. Neutralization of TNFα in tumor with a novel nanobody potentiates paclitaxel-therapy and inhibits metastasis in breast cancer.

    PubMed

    Ji, Xuemei; Peng, Zhengxin; Li, Xiaorui; Yan, Zhonghui; Yang, Yue; Qiao, Zheng; Liu, Yu

    2017-02-01

    Metastatic disease is the major cause of death from cancer, and immunotherapy and chemotherapy have had limited success in reversing its progression. Researchers have suggested that inflammatory factors in the tumor environment can promote cancer invasion and metastasis, stimulating cancer progression. Thus, novel strategies that target cytokines and modulate the tumor microenvironment may emerge as important approaches for treating metastatic breast cancer. Specific neutralization of pathogenic TNF signaling using a TNFα antibody has gained increasing attention. Considering this, a selective human TNFα neutralized antibody was generated based on nanobody technology. A TNFα-specific nanobody was produced in Pichia pastoris with a molecular mass of 15 kDa and affinity constant of 2.05 nM. In the proliferation experiment, the TNFα nanobody could inhibit the proliferation of the breast cancer cell line MCF-7 induced by hTNFα in a dose-dependent manner. In the microinvasion model, the TNFα nanobody could inhibit the migration of the breast cancer cell lines MCF-7, MDA-MB-231 and the invasiveness of MDA-MB-231 induced by hTNFα in a dose-dependent manner. Drug administration of the combination of paclitaxel with the TNFα nanobody in vivo significantly enhanced the efficacy against 4T-1 breast tumor proliferation and lung metastasis; meanwhile, E-cadherin tumor epithelial marker expression was upregulated, supporting the anti-tumor therapeutic relevance of paclitaxel and the TNFα nanobody on EMT. This study highlights the importance of neutralizing low TNFα levels in the tumor microenvironment to sensitize the chemotherapeutic response, which has attractive potential for clinical applications. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. CD47 blockade inhibits tumor progression human osteosarcoma in xenograft models

    PubMed Central

    Zhang, Shui-Jun; Zhao, Chen; Qiu, Bin-Song; Gu, Hai-Feng; Hong, Jian-Fei; Cao, Li; Chen, Yu; Xia, Bing; Bi, Qin; Wang, Ya-Ping

    2015-01-01

    Osteosarcoma is the most common bone tumors in children and adolescents. Despite intensive chemotherapy, patients with advanced disease still have a poor prognosis, illustrating the need for alternative therapies. In this study, we explored the use of antibodies that block CD47 with a tumor growth suppressive effect on osteosarcoma. We first found that up-regulation of CD47 mRNA levels in the tumorous tissues from eight patients with osteosarcoma when compared with that in adjacent non-tumorous tissues. Further western-blot (WB) and immunohistochemistry (IHC) demonstrated that CD47 protein level was highly expressed in osteosarcoma compared to normal osteoblastic cells and adjacent non-tumorous tissues. Osteosarcoma cancer stem cell markers staining shown that the majority of CD44+ cells expressed CD47 albeit with different percentages (ranging from 80% to 99%). Furthermore, high CD47 mRNA expression levels were associated with a decreased probability of progression-free and overall survival. In addition, blockade of CD47 by specific Abs suppresses the invasive ability of osteosarcoma tumor cells and further inhibits spontaneous pulmonary metastasis of KRIB osteosarcoma cells in vivo. Finally, CD47 blockade increases macrophage phagocytosis of osteosarcoma tumor cells. In conclusion, our findings demonstrate that CD47 is a critical regulator in the metastasis of osteosarcoma and suggest that targeted inhibition of this antigen by anti-CD47 may be a novel immunotherapeutic approach in the management of this tumor. PMID:26093091

  9. Cdk4 deficiency inhibits skin tumor development but does not affect normal keratinocyte proliferation.

    PubMed

    Rodriguez-Puebla, Marcelo L; Miliani de Marval, Paula L; LaCava, Margaret; Moons, David S; Kiyokawa, Hiroaki; Conti, Claudio J

    2002-08-01

    Most human tumors have mutations that result in deregulation of the cdk4/cyclin-Ink4-Rb pathway. Overexpression of D-type cyclins or cdk4 and inactivation of Ink4 inhibitors are common in human tumors. Conversely, lack of cyclin D1 expression results in significant reduction in mouse skin and mammary tumor development. However, complete elimination of tumor development was not observed in these models, suggesting that other cyclin/cdk complexes play an important role in tumorigenesis. Here we described the effects of cdk4 deficiency on mouse skin proliferation and tumor development. Cdk4 deficiency resulted in a 98% reduction in the number of tumors generated through the two-stage carcinogenesis model. The absence of cdk4 did not affect normal keratinocyte proliferation and both wild-type and cdk4 knockout epidermis are equally affected after topical treatment with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), resulting in epidermal hyperplasia. In similar fashion, cdk4 knockout keratinocytes proliferated well in an in vivo model of wound-induced proliferation. Biochemical studies in mouse epidermis showed that cdk6 activity increased twofold in cdk4-deficient mice compared to wild-type siblings. These results suggest that therapeutic approaches to inhibit cdk4 activity could provide a target to inhibit tumor development with minimal or no effect in normal tissue.

  10. Inhibition of Lysyl Oxidases Impairs Migration and Angiogenic Properties of Tumor-Associated Pericytes.

    PubMed

    Ribeiro, Aline Lopes; Kaid, Carolini; Silva, Patrícia B G; Cortez, Beatriz A; Okamoto, Oswaldo Keith

    2017-01-01

    Pericytes are important cellular components of the tumor microenviroment with established roles in angiogenesis and metastasis. These two cancer hallmarks are modulated by enzymes of the LOX family, but thus far, information about LOX relevance in tumor-associated pericytes is lacking. Here, we performed a comparative characterization of normal and tumoral pericytes and report for the first time the modulatory effects of LOX enzymes on activated pericyte properties. Tumoral pericytes isolated from childhood ependymoma and neuroblastoma specimens displayed angiogenic properties in vitro and expressed typical markers, including CD146, NG2, and PDGFRβ. Expression of all LOX family members could be detected in both normal and tumor-associated pericytes. In most pericyte samples, LOXL3 was the family member displaying the highest transcript levels. Inhibition of LOX/LOXL activity with the inhibitor β-aminopropionitrile (βAPN) significantly reduced migration of pericytes, while proliferation rates were kept unaltered. Formation of tube-like structures in vitro by pericytes was also significantly impaired upon inhibition of LOX/LOXL activity with βAPN, which induced more prominent effects in tumor-associated pericytes. These findings reveal a novel involvement of the LOX family of enzymes in migration and angiogenic properties of pericytes, with implications in tumor development and in therapeutic targeting tumor microenvironment constituents.

  11. Inhibition of Lysyl Oxidases Impairs Migration and Angiogenic Properties of Tumor-Associated Pericytes

    PubMed Central

    Kaid, Carolini; Silva, Patrícia B. G.; Cortez, Beatriz A.

    2017-01-01

    Pericytes are important cellular components of the tumor microenviroment with established roles in angiogenesis and metastasis. These two cancer hallmarks are modulated by enzymes of the LOX family, but thus far, information about LOX relevance in tumor-associated pericytes is lacking. Here, we performed a comparative characterization of normal and tumoral pericytes and report for the first time the modulatory effects of LOX enzymes on activated pericyte properties. Tumoral pericytes isolated from childhood ependymoma and neuroblastoma specimens displayed angiogenic properties in vitro and expressed typical markers, including CD146, NG2, and PDGFRβ. Expression of all LOX family members could be detected in both normal and tumor-associated pericytes. In most pericyte samples, LOXL3 was the family member displaying the highest transcript levels. Inhibition of LOX/LOXL activity with the inhibitor β-aminopropionitrile (βAPN) significantly reduced migration of pericytes, while proliferation rates were kept unaltered. Formation of tube-like structures in vitro by pericytes was also significantly impaired upon inhibition of LOX/LOXL activity with βAPN, which induced more prominent effects in tumor-associated pericytes. These findings reveal a novel involvement of the LOX family of enzymes in migration and angiogenic properties of pericytes, with implications in tumor development and in therapeutic targeting tumor microenvironment constituents. PMID:28553358

  12. Inhibition and regression of tumors in hamster DMBA model following laser microvascular targeting

    NASA Astrophysics Data System (ADS)

    McMillan, Kathleen; Wang, Zhi; Shapshay, Stanley M.

    1998-07-01

    Vascular targeting is a recent approach to cancer therapy that aims at damaging tumor vasculature to induce tumor cell hypoxia and subsequent cell death. Squamous cell cancer arises in the superficial mucosal and cutaneous epithelial layers, and tumor microvasculature therefore may be particularly well suited for targeting by selective photothermolysis. An initial evaluation of the effect of selective eradication of microvasculature on tumor development was undertaken here using the chemically-induced hamster cheek pouch model and a 585 nm pulsed dye laser. In a first group of 6 hamsters, progression of premalignant mucosal lesions was compared between control and laser treatment groups, and laser-induced regression of established tumors was evaluated. In a second group of 12 hamsters, the number of laser treatments required to produce complete regression of tumors of the buccal mucosa was determined. The effect of the laser on tumors appearing on the skin in these animals was also investigated. These experiments showed that laser treatment inhibited tumor development and caused complete regression of established tumors 10 mm3 or smaller. Photothermal microvascular targeting may be useful in treating dyplasia and early tumors of the upper aerodigestive tract and skin, with fewer adverse sequelae than existing modalities.

  13. IGF-1R inhibition induces schedule-dependent sensitization of human melanoma to temozolomide.

    PubMed

    Ramcharan, Roger; Aleksic, Tamara; Kamdoum, Wilfride Petnga; Gao, Shan; Pfister, Sophia X; Tanner, Jordan; Bridges, Esther; Asher, Ruth; Watson, Amanda J; Margison, Geoffrey P; Woodcock, Mick; Repapi, Emmanouela; Li, Ji-Liang; Middleton, Mark R; Macaulay, Valentine M

    2015-11-24

    Prior studies implicate type 1 IGF receptor (IGF-1R) in mediating chemo-resistance. Here, we investigated whether IGF-1R influences response to temozolomide (TMZ), which generates DNA adducts that are removed by O6-methylguanine-DNA methyltransferase (MGMT), or persist causing replication-associated double-strand breaks (DSBs). Initial assessment in 10 melanoma cell lines revealed that TMZ resistance correlated with MGMT expression (r = 0.79, p = 0.009), and in MGMT-proficient cell lines, with phospho-IGF-1R (r = 0.81, p = 0.038), suggesting that TMZ resistance associates with IGF-1R activation. Next, effects of IGF-1R inhibitors (IGF-1Ri) AZ3801 and linsitinib (OSI-906) were tested on TMZ-sensitivity, cell cycle progression and DSB induction. IGF-1Ri sensitized BRAF wild-type and mutant melanoma cells to TMZ in vitro, an effect that was independent of MGMT. Cells harboring wild-type p53 were more sensitive to IGF-1Ri, and showed schedule-dependent chemo-sensitization that was most effective when IGF-1Ri followed TMZ. This sequence sensitized to clinically-achievable TMZ concentrations and enhanced TMZ-induced apoptosis. Simultaneous or prior IGF-1Ri caused less effective chemo-sensitization, associated with increased G1 population and reduced accumulation of TMZ-induced DSBs. Clinically relevant sequential (TMZ → IGF-1Ri) treatment was tested in mice bearing A375M (V600E BRAF, wild-type p53) melanoma xenografts, achieving peak plasma/tumor IGF-1Ri levels comparable to clinical Cmax, and inducing extensive intratumoral apoptosis. TMZ or IGF-1Ri caused minor inhibition of tumor growth (gradient reduction 13%, 25% respectively), while combination treatment caused supra-additive growth delay (72%) that was significantly different from control (p < 0.01), TMZ (p < 0.01) and IGF-1Ri (p < 0.05) groups. These data highlight the importance of scheduling when combining IGF-1Ri and other targeted agents with drugs that induce replication-associated DNA damage.

  14. Reactivation of mutant p53 by a dietary-related compound phenethyl isothiocyanate inhibits tumor growth

    PubMed Central

    Aggarwal, M; Saxena, R; Sinclair, E; Fu, Y; Jacobs, A; Dyba, M; Wang, X; Cruz, I; Berry, D; Kallakury, B; Mueller, S C; Agostino, S D; Blandino, G; Avantaggiati, M L; Chung, F-L

    2016-01-01

    Mutations in the p53 tumor-suppressor gene are prevalent in human cancers. The majority of p53 mutations are missense, which can be classified into contact mutations (that directly disrupts the DNA-binding activity of p53) and structural mutations (that disrupts the conformation of p53). Both of the mutations can disable the normal wild-type (WT) p53 activities. Nevertheless, it has been amply documented that small molecules can rescue activity from mutant p53 by restoring WT tumor-suppressive functions. These compounds hold promise for cancer therapy and have now entered clinical trials. In this study, we show that cruciferous-vegetable-derived phenethyl isothiocyanate (PEITC) can reactivate p53 mutant under in vitro and in vivo conditions, revealing a new mechanism of action for a dietary-related compound. PEITC exhibits growth-inhibitory activity in cells expressing p53 mutants with preferential activity toward p53R175, one of the most frequent ‘hotspot' mutations within the p53 sequence. Mechanistic studies revealed that PEITC induces apoptosis in a p53R175 mutant-dependent manner by restoring p53 WT conformation and transactivation functions. Accordingly, in PEITC-treated cells the reactivated p53R175 mutant induces apoptosis by activating canonical WT p53 targets, inducing a delay in S and G2/M phase, and by phosphorylating ATM/CHK2. Interestingly, the growth-inhibitory effects of PEITC depend on the redox state of the cell. Further, PEITC treatments render the p53R175 mutant sensitive to degradation by the proteasome and autophagy in a concentration-dependent manner. PEITC-induced reactivation of p53R175 and its subsequent sensitivity to the degradation pathways likely contribute to its anticancer activities. We further show that dietary supplementation of PEITC is able to reactivate WT activity in vivo as well, inhibiting tumor growth in xenograft mouse model. These findings provide the first example of mutant p53 reactivation by a dietary compound and

  15. B7-H3 silencing inhibits tumor progression of mantle cell lymphoma and enhances chemosensitivity.

    PubMed

    Zhang, Wei; Wang, Yanfang; Wang, Jing; Dong, Fei; Zhu, Mingxia; Wan, Wenli; Li, Haishen; Wu, Feifei; Yan, Xinxing; Ke, Xiaoyan

    2015-01-01

    B7-H3 (CD276), known as a member of B7 immunoregulatory family, is a type I transmembrane glycoprotein aberrantly expressed in numerous types of cancer and associated with poor prognosis. However, the role of B7-H3 in oncogenesis and chemosensitivity of mantle cell lymphoma (MCL) remains unknown. We determined the effects of downregulating B7-H3 expression on tumor progression and the sensitivity of chemotherapeutic drug in mantle cell lymphoma. B7-H3 knockdown was performed using lentivirus transduction in the Maver and Z138 mantle cell lymphoma cell lines, respectively. The effects of B7-H3 on cell proliferation, cycle, migration and invasion were investigated by CCK-8 assay, methyl cellulose colony forming assay, PI staining, and Transwell assays in vitro. By establishing Maver and Z138 xenograft models, the effects of B7-H3 on tumorigenicity were observed, and Ki-67 and PCNA was detected by immunohistochemistry. The downregulation of B7-H3 significantly decreased tumor proliferation in MCL in vitro and in vivo. In the B7-H3 knockdown groups of Maver and Z138 xenograft models, the mean inhibition rate of tumor growth was 59.1 and 65.0% (p=0.010 and 0.003), and the expression of both Ki-67 and PCNA were significantly lower, respectively. After B7-H3 silencing, the cell cycles of Maver and Z138 were both arrested at G0/G1 phase, and the cell migration rates and invasion capacity were decreased as well. Moreover, the impacts of B7-H3 RNAi on the antitumor effect of chemotherapy drugs were determined with CCK-8 and Annexin V-FITC/PI assays in vitro and with xenograft models in vivo. The silencing of B7-H3 increased the sensitivity of Maver and Z138 cells to rituximab and bendamustine and enhanced the drug-induced apoptosis, respectively. Our study demonstrates for the first time that B7-H3 promotes mantle cell lymphoma progression and B7-H3 knockdown significantly enhances the chemosensitivity. This may provide a new therapeutic approach to mantle cell lymphoma.

  16. Hyperthermia Sensitizes Glioma Stem-like Cells to Radiation By Inhibiting AKT Signaling

    PubMed Central

    Man, Jianghong; Shoemake, Jocelyn D.; Ma, Tuopu; Rizzo, Anthony E.; Godley, Andrew R.; Wu, Qiulian; Mohammadi, Alireza M.; Bao, Shideng; Rich, Jeremy N.; Yu, Jennifer S.

    2015-01-01

    Glioma stem-like cells (GSCs) are a subpopulation of cells in tumors that are believed to mediate self-renewal and relapse in glioblastoma (GBM), the most deadly form of primary brain cancer. In radiation oncology, hyperthermia is known to radiosensitize cells and it is re-emerging as a treatment option for patients with GBM. In this study, we investigated the mechanisms of hyperthermic radiosensitization in GSCs by a phosphokinase array that revealed the survival kinase AKT as a critical sensitization determinant. GSCs treated with radiation alone exhibited increased AKT activation, but the addition of hyperthermia before radiotherapy reduced AKT activation and impaired GSC proliferation. Introduction of constitutively active AKT in GSCs compromised hyperthermic radiosensitization. Pharmacologic inhibition of PI3K further enhanced the radiosensitizing effects of hyperthermia. In a preclinical orthotopic transplant model of human GBM, thermoradiotherapy reduced pS6 levels, delayed tumor growth and extended animal survival. Together, our results offer a preclinical proof-of-concept for further evaluation of combined hyperthermia and radiation for GBM treatment. PMID:25712125

  17. T-Type Ca2+ Channel Inhibition Sensitizes Ovarian Cancer to Carboplatin.

    PubMed

    Dziegielewska, Barbara; Casarez, Eli V; Yang, Wesley Z; Gray, Lloyd S; Dziegielewski, Jaroslaw; Slack-Davis, Jill K

    2016-03-01

    Ovarian cancer is the deadliest gynecologic cancer, due in large part to the diagnosis of advanced stage disease, the development of platinum resistance, and inadequate treatment alternatives. Recent studies by our group and others have shown that T-type calcium (Ca(2+)) channels play a reinforcing role in cancer cell proliferation, cell-cycle progression, and apoptosis evasion. Therefore, we investigated whether T-type Ca(2+) channels affect ovarian tumor growth and response to platinum agents. Inhibition of T-type Ca(2+) channels with mibefradil or by silencing expression resulted in growth suppression in ovarian cancer cells with a simultaneous increase in apoptosis, which was accompanied by decreased expression of the antiapoptotic gene survivin (BIRC5). Analysis of intracellular signaling revealed mibefradil reduced AKT phosphorylation, increased the levels and nuclear retention of FOXO transcription factors that repress BIRC5 expression, and decreased the expression of FOXM1, which promotes BIRC5 expression. Combining carboplatin with mibefradil synergistically increased apoptosis in vitro. Importantly, mibefradil rendered platinum-resistant ovarian tumors sensitive to carboplatin in a mouse model of peritoneal metastasis. Together, the data provide rationale for future use of T-type channel antagonists together with platinum agents for the treatment of ovarian cancer. ©2016 American Association for Cancer Research.

  18. Loss of ARID1A expression sensitizes cancer cells to PI3K- and AKT-inhibition

    PubMed Central

    Samartzis, Eleftherios P; Gutsche, Katrin; Dedes, Konstantin J; Fink, Daniel; Stucki, Manuel; Imesch, Patrick

    2014-01-01

    ARID1A mutations are observed in various tumors, including ovarian clear cell (OCCC) and endometrioid carcinomas, endometrial, and breast carcinomas. They commonly result in loss of ARID1A-protein expression and frequently co-occur with PI3K/AKT-pathway activating mechanisms. The aim of this study was to test the hypothesis as to whether PI3K/AKT-pathway activation is a critical mechanism in ARID1A-mutated tumors and if consequently ARID1A-deficient tumors show increased sensitivity to treatment with PI3K- and AKT-inhibitors. Upon ARID1A knockdown, MCF7 breast cancer cells and primary MRC5 cells exhibited a significantly increased sensitivity towards the AKT-inhibitors MK-2206 and perifosine, as well as the PI3K-inhibitor buparlisib. Knockdown of ARID1A in MCF7 led to an increase of pAKT-Ser473. AKT-inhibition with MK-2206 led to increased apoptosis and to a decrease of pS6K in ARID1A-depleted MCF7 cells but not in the controls. In five OCCC cell lines ARID1A-deficiency correlated with increased pAKT-Ser473 levels and with sensitivity towards treatment with the AKT-inhibitor MK-2206. In conclusion, ARID1A-deficient cancer cells demonstrate an increased sensitivity to treatment with small molecule inhibitors of the PI3K/AKT-pathway. These findings suggest a specific requirement of the PI3K/AKT pathway in ARID1A-deficient tumors and reveal a synthetic lethal interaction between loss of ARID1A expression and inhibition of the PI3K/AKT pathway. PMID:24979463

  19. Decursin inhibits vasculogenesis in early tumor progression by suppression of endothelial progenitor cell differentiation and function.

    PubMed

    Jung, Seok Yun; Choi, Jin Hwa; Kwon, Sang-Mo; Masuda, Haruchika; Asahara, Takayuki; Lee, You-Mie

    2012-05-01

    Endothelial progenitor cells (EPCs) contribute to the tumor vasculature during tumor progression. Decursin isolated from the herb Angelica gigas is known to possess potent anti-inflammatory activities. Recently, we reported that decursin is a novel candidate for an angiogenesis inhibitor [Jung et al., 2009]. In this study, we investigated whether decursin regulates EPC differentiation and function to inhibit tumor vasculogenesis. We isolated AC133+ cells from human cord blood and decursin significantly decreased the number of EPC colony forming units of human cord blood-derived AC133+ cells that produce functional EPC progenies. Decursin dose-dependently decreased the cell number of EPC committing cells as demonstrated by EPC expansion studies. Decursin inhibited EPC differentiation from progenitor cells into spindle-shaped EPC colonies. Additionally, decursin inhibited proliferation and migration of early EPCs isolated from mouse bone marrow. Furthermore, decursin suppressed expression of angiopoietin-2, angiopoietin receptor Tie-2, Flk-1 (vascular endothelial growth factor receptor-2), and endothelial nitric oxide synthase in mouse BM derived EPCs in a dose-dependent manner. Decursin suppressed tube formation ability of EPCs in collaboration with HUVEC. Decursin (4 mg/kg) inhibited tumor-induced mobilization of circulating EPCs (CD34 + /VEGFR-2+ cells) from bone marrow and early incorporation of Dil-Ac-LDL-labeled or green fluorescent protein (GFP)+ EPCs into neovessels of xenograft Lewis lung carcinoma tumors in wild-type- or bone-marrow-transplanted mice. Accordingly, decursin attenuated EPC-derived endothelial cells in neovessels of Lewis lung carcinoma tumor masses grown in mice. Together, decursin likely affects EPC differentiation and function, thereby inhibiting tumor vasculogenesis in early tumorigenesis. Copyright © 2012 Wiley Periodicals, Inc.

  20. Sensitivity of malignant rhabdoid tumor cell lines to PD 0332991 is inversely correlated with p16 expression

    SciTech Connect

    Katsumi, Yoshiki; Iehara, Tomoko; Miyachi, Mitsuru; Yagyu, Shigeki; Tsubai-Shimizu, Satoko; Kikuchi, Ken; Tamura, Shinichi; Kuwahara, Yasumichi; Tsuchiya, Kunihiko; Kuroda, Hiroshi; Sugimoto, Tohru; Houghton, Peter J.; Hosoi, Hajime

    2011-09-16

    Highlights: {yields} PD 0332991 (PD) could suppress four of five malignant rhabdoid tumor (MRT) cell lines. {yields} The sensitivity of the MRT cell lines to PD was inversely correlated with p16 expression (r = 0.951). {yields} p16 expression in MRT could be used to predict its sensitivity to PD. {yields} PD may be an attractive agent for patients with MRT whose tumors express low levels of p16. -- Abstract: Malignant rhabdoid tumor (MRT) is a rare and highly aggressive neoplasm of young children. MRT is characterized by inactivation of integrase interactor 1 (INI1). Cyclin-dependent kinase 4 (CDK4), which acts downstream of INI1, is required for the proliferation of MRT cells. Here we investigated the effects of PD 0332991 (PD), a potent inhibitor of CDK4, against five human MRT cell lines (MP-MRT-AN, KP-MRT-RY, G401, KP-MRT-NS, KP-MRT-YM). In all of the cell lines except KP-MRT-YM, PD inhibited cell proliferation >50%, (IC{sub 50} values 0.01 to 0.6 {mu}M) by WST-8 assay, and induced G1-phase cell cycle arrest, as shown by flow cytometry and BrdU incorporation assay. The sensitivity of the MRT cell lines to PD was inversely correlated with p16 expression (r = 0.951). KP-MRT-YM cells overexpress p16 and were resistant to the growth inhibitory effect of PD. Small interfering RNA against p16 significantly increased the sensitivity of KP-MRT-YM cells to PD (p < 0.05). These results suggest that p16 expression in MRT could be used to predict its sensitivity to PD. PD may be an attractive agent for patients with MRT whose tumors express low levels of p16.

  1. Ranitidine modifies myeloid cell populations and inhibits breast tumor development and spread in mice

    PubMed Central

    Vila-Leahey, Ava; Oldford, Sharon A.; Marignani, Paola A.; Wang, Jun; Haidl, Ian D.; Marshall, Jean S.

    2016-01-01

    ABSTRACT Histamine receptor 2 (H2) antagonists are widely used clinically for the control of gastrointestinal symptoms, but also impact immune function. They have been reported to reduce tumor growth in established colon and lung cancer models. Histamine has also been reported to modify populations of myeloid-derived suppressor cells (MDSCs). We have examined the impact of the widely used H2 antagonist ranitidine, on both myeloid cell populations and tumor development and spread, in three distinct models of breast cancer that highlight different stages of cancer progression. Oral ranitidine treatment significantly decreased the monocytic MDSC population in the spleen and bone marrow both alone and in the context of an orthotopic breast tumor model. H2 antagonists ranitidine and famotidine, but not H1 or H4 antagonists, significantly inhibited lung metastasis in the 4T1 model. In the E0771 model, ranitidine decreased primary tumor growth while omeprazole treatment had no impact on tumor development. Gemcitabine treatment prevented the tumor growth inhibition associated with ranitidine treatment. In keeping with ranitidine-induced changes in myeloid cell populations in non-tumor-bearing mice, ranitidine also delayed the onset of spontaneous tumor development, and decreased the number of tumors that developed in LKB1−/−/NIC mice. These results indicate that ranitidine alters monocyte populations associated with MDSC activity, and subsequently impacts breast tumor development and outcome. Ranitidine has potential as an adjuvant therapy or preventative agent in breast cancer and provides a novel and safe approach to the long-term reduction of tumor-associated immune suppression. PMID:27622015

  2. Preparation of Conjugated Polymer Grafted with H2O2-Sensitive Prodrug for Cell Imaging and Tumor Cell Killing.

    PubMed

    Li, Meng; Li, Shengliang; Chen, Hui; Hu, Rong; Liu, Libing; Lv, Fengting; Wang, Shu

    2016-01-13

    In this work, a new conjugated polymer poly(fluorene-co-phenylene) derivative containing pendent quaternized chlormethine (PFP-Chl) was synthesized by covalent linking small molecular prodrug groups onto conjugated polymer side chains. H2O2-sensitive prodrug with an eight-member-cyclic boronate ester structure could suffer from H2O2-triggered nitrogen mustard release and further DNA cross-linking and alkylation. PFP-Chl combines therapeutic characteristic with excellent optical property of conjugated polymers. It is found that PFP-Chl could enter into cells by endocytosis to simultaneously exhibit abilities of fluorescent imaging and tumor cell inhibition.

  3. miR-218 inhibited tumor angiogenesis by targeting ROBO1 in gastric cancer.

    PubMed

    Xiangyuan, Zhang; Jiaqiang, Dong; Yan, He; Ming, Zhao; Zhen, Liu; Na, Wang; Mingzuo, Jiang; Zhe, Zhang; Gang, Liu; Haiming, Liu; Yongzhan, Nie; Daiming, Fan; Jun, Tie

    2017-03-17

    Aberrant expression of miRNAs is involved in several carcinogenic processes, including tumor growth, metastasis and angiogenesis. The aim of this study was to determine the role of miR-218 in gastric cancer angiogenesis. In situ hybridization was performed on a set of tissue microarray samples to assess the difference in miR-218 expression in vessels between tumor tissues and normal gastric mucosa. In vitro, ectopic expression of miR-218 disturbed the tubular structure and inhibited the migration of endothelial cells. Motility and tube formation were rescued when miR-218 was downregulated. Moreover, miR-218 suppressed endothelial cell sprouting in a fibrin bead sprouting assay. Subsequently, we identified ROBO1 as a target of miR-218 in endothelial cells and determined it was responsible for the effect of miR-218 on tumor angiogenesis. In vivo, local injection of mature miR-218 in xenografted tumors disrupted the vessel plexus and thus inhibited tumor growth. Taken together, our study demonstrated an anti-angiogenic role of miR-218 in gastric cancer and indicated that delivery of miR-218 may be a potential therapeutic strategy to inhibit tumor angiogenesis.

  4. Inhibition of mouse B16 melanoma by sodium butyrate correlated to tumor associated macrophages differentiation suppression

    PubMed Central

    Xiong, Fen; Mou, Yun-Zhu; Xiang, Xiao-Yan

    2015-01-01

    Objective: As one member of the histone deacetylase inhibitor (HDACi) family, Sodium butyrate (NaB) was found out that could be used as a differentiation inducer of much cancer cell. But its effects on tumor microenvironment cells are not well recognized. The goal of this research is to investigate the effect of NaB on B16 melanoma and analysis its relevant mechanism. Methods: We observed the effect of sodium butyrate on B16 melanoma in vivo and in vitro. MTT method was performed to detect cell apoptosis rate after treatment. Tumor associated macrophage infiltration condition was detected by flow cytometry. Western-blotting and immunohistochemical method were used to detect the expression of tumor associated macrophage cytokines. Results: A certain concentration of sodium butyrate could effectively inhibit B16 melanoma growth in vivo and in vitro, and this inhibition effects related to the suppression of tumor associated macrophage differentiation. At the same time we observed the relevant macrophage factors were down-regulated compared to the control. Conclusion: Sodium butyrate could effectively inhibit B16 melanoma growth through suppressing tumor associated macrophage proliferation and reduce relevant pro-tumor macrophage factors expression, which may help to promote the clinical study of melanoma epigenetic therapy. PMID:26064327

  5. Porfimer-sodium (Photofrin-II) in combination with ionizing radiation inhibits tumor-initiating cell proliferation and improves glioblastoma treatment efficacy

    PubMed Central

    Benayoun, Liat; Schaffer, Moshe; Bril, Rotem; Gingis-Velitski, Svetlana; Segal, Ehud; Nevelsky, Alexsander; Satchi-Fainaro, Ronit; Shaked, Yuval

    2013-01-01

    Tumor relapse and tumor cell repopulation has been explained partially by the drug-free break period between successive conventional treatments. Strategies to overcome tumor relapse have been proposed, such as the use of chemotherapeutic drugs or radiation in small, frequent fractionated doses without an extended break period between treatment intervals. Yet, tumors usually acquire resistance and eventually escape the therapy. Several mechanisms have been proposed to explain the resistance of tumors to therapy, one of which involves the cancer stem cell or tumor-initiating cell (TIC) concept. TICs are believed to resist many conventional therapies, in part due to their slow proliferation and self-renewal capacities. Therefore, emerging efforts to eradicate TICs are being undertaken. Here we show that treatment with Photofrin II, among the most frequently used photosensitizers, sensitized a TIC-enriched U-87MG human glioblastoma cell to radiation, and improve treatment outcome when used in combination with radiotherapy. A U-87MG tumor cell population enriched with radiation-resistant TICs becomes radio-sensitive, and an inhibition of cell proliferation and an increase in apoptosis are found in the presence of Photofrin II. Furthermore, U-87MG tumors implanted in mice treated with Photofrin II and radiation exhibit a significant reduction in angiogenesis and vasculogenesis, and an increased percentage of apoptotic TICs when compared with tumors grown in mice treated with radiation alone. Collectively, our results offer a new possible explanation for the therapeutic effects of radiosensitizing agents, and suggest that combinatorial treatment modalities can effectively prolong treatment outcome of glioblastoma tumors by inhibiting tumor growth mediated by TICs. PMID:23114641

  6. Ganoderma lucidum exerts anti-tumor effects on ovarian cancer cells and enhances their sensitivity to cisplatin.

    PubMed

    Zhao, Sufen; Ye, Gang; Fu, Guodong; Cheng, Jian-Xin; Yang, Burton B; Peng, Chun

    2011-05-01

    Ganoderma lucidum is a herbal mushroom known to have many health benefits, including the inhibition of tumor cell growth. However, the effect of Ganoderma lucidum on epithelial ovarian cancer (EOC), the most fatal gynecological malignancy, has not yet been reported. In this study, we determined whether Ganoderma lucidum regulates EOC cell activity. Using several cell lines derived from EOC, we found that Ganoderma lucidum strongly decreased cell numbers in a dose-dependent manner. Ganoderma lucidum also inhibited colony formation, cell migration and spheroid formation. In particular, Ganoderma lucidum was effective in inhibiting cell growth in both chemosensitive and chemoresistant cells and the treatment with Ganoderma lucidum significantly enhanced the effect of cisplatin on EOC cells. Furthermore, Ganoderma lucidum induced cell cycle arrest at the G2/M phase and also induced apoptosis by activating caspase 3. Finally, Ganoderma lucidum increased p53 but inhibited Akt expression. Taken together, these findings suggest that Ganoderma lucidum exerts multiple anti-tumor effects on ovarian cancer cells and can enhance the sensitivity of EOC cells to cisplatin.

  7. Tumor Necrosis Factor-α Sensitizes Breast Cancer Cells to Natural Products with Proteasome-Inhibitory Activity Leading to Apoptosis

    PubMed Central

    Lu, Li; Shi, Wenli; Deshmukh, Rahul R.; Long, Jie; Cheng, Xiaoli; Ji, Weidong; Zeng, Guohua; Chen, Xianliang; Zhang, Yajie; Dou, Q. Ping

    2014-01-01

    The inflammatory microenvironment plays an important role in the process of tumor development. Tumor necrosis factor-α (TNF-α), a key pro-inflammatory cytokine, has a significant role in this process. Natural medicinal products such as Withaferin A (WA) and Celastrol (Cel) have shown anti-cancer and anti-inflammatory properties that can be attributed to multiple mechanisms including, but not limited to, apoptosis induction due to the inhibition of proteasomal activities. This study aimed to investigate the effects of TNF-α in combination with WA or Cel in vitro in MDA-MB-231 breast cancer cells. TNF-α, when combined with WA or Cel, activated caspase-3 and -9 and downregulated XIAP in a dose-dependent manner, leading to induction of apoptosis in MDA-MB-231 breast cancer cells. The combination also caused accumulation of the proteasomal target protein IκBα, resulting in inhibition of the nuclear translocation of nuclear factor-κB (NF-κB). Taken together, these results suggest that TNF-α could sensitize breast cancer cells MDA-MB-231 to WA and Cel, at least in part, through inhibiting the activation of NF-κB signaling, leading to XIAP inhibition with subsequent upregulation of caspase-3 and -9 activities. Thus, the anti-cancer activities of TNF-α are enhanced when combined with the natural proteasome inhibitors, WA or Cel. PMID:25419573

  8. Statins improve survival by inhibiting spontaneous metastasis and tumor growth in a mouse melanoma model

    PubMed Central

    Tsubaki, Masanobu; Takeda, Tomoya; Kino, Toshiki; Obata, Naoya; Itoh, Tatsuki; Imano, Motohiro; Mashimo, Kenji; Fujiwara, Daichiro; Sakaguchi, Katsuhiko; Satou, Takao; Nishida, Shozo

    2015-01-01

    Metastatic melanoma is a life-threatening disease for which no effective treatment is currently available. In melanoma cells, Rho overexpression promotes invasion and metastasis. However, the effect of statins on spontaneous metastasis and tumor growth remains unclear. In the present study, we investigated the mechanism of statin-mediated tumor growth and metastasis inhibition in an in vivo model. We found that statins significantly inhibited spontaneous metastasis and tumor growth. Statins inhibited the mRNA expression and enzymatic activities of matrix metalloproteinases (MMPs) in vivo and also suppressed the mRNA and protein expression of very late antigens (VLAs). Moreover, statins inhibited the prenylation of Rho as well as the phosphorylation of LIM kinase, serum response factor (SRF), and c-Fos downstream of the Rho signaling pathway. In addition, statins enhanced p53, p21, and p27 expression and reduced phosphorylation of cyclin-dependent kinase and expression of cyclin D1 and E2. These results indicate that statins suppress Rho signaling pathways, thereby inhibiting tumor metastasis and growth. Furthermore, statins markedly improved the survival rate in a metastasis model, suggesting that statins have potential clinical applications for the treatment of metastatic cancers. PMID:26693069

  9. SAMHD1 is down regulated in lung cancer by methylation and inhibits tumor cell proliferation

    SciTech Connect

    Wang, Jia-lei; Lu, Fan-zhen; Shen, Xiao-Yong; Wu, Yun; Zhao, Li-ting

    2014-12-12

    Highlights: • SAMHD1 expression level is down regulated in lung adenocarcinoma. • The promoter of SAMHD1 is methylated in lung adenocarcinoma. • Over expression of SAMHD1 inhibits the proliferation of lung cancer cells. - Abstract: The function of dNTP hydrolase SAMHD1 as a viral restriction factor to inhibit the replication of several viruses in human immune cells was well established. However, its regulation and function in lung cancer have been elusive. Here, we report that SAMHD1 is down regulated both on protein and mRNA levels in lung adenocarcinoma compared to adjacent normal tissue. We also found that SAMHD1 promoter is highly methylated in lung adenocarcinoma, which may inhibit its gene expression. Furthermore, over expression of the SAMHD1 reduces dNTP level and inhibits the proliferation of lung tumor cells. These results reveal the regulation and function of SAMHD1 in lung cancer, which is important for the proliferation of lung tumor cells.

  10. Growth inhibition and pro-apoptotic activity of violacein in Ehrlich ascites tumor.

    PubMed

    Bromberg, Natália; Dreyfuss, Juliana L; Regatieri, Caio V; Palladino, Marcelly V; Durán, Nelson; Nader, Helena B; Haun, Marcela; Justo, Giselle Z

    2010-06-07

    The continuing threat to biodiversity lends urgency to the need of identification of sustainable source of natural products. This is not so much trouble if there is a microbial source of the compound. Herein, violacein, a natural indolic pigment extracted from Chromobacterium violaceum, was evaluated for its antitumoral potential against the Ehrlich ascites tumor (EAT) in vivo and in vitro. Evaluation of violacein cytotoxicity using different endpoints indicated that EAT cells were twofold (IC(50)=5.0 microM) more sensitive to the compound than normal human peripheral blood lymphocytes. In vitro studies indicated that violacein cytotoxicity to EAT cells is mediated by a rapid (8-12h) production of reactive oxygen species (ROS) and a decrease in intracellular GSH levels, probably due to oxidative stress. Additionally, apoptosis was primarily induced, as demonstrated by an increase in Annexin-V positive cells, concurrently with increased levels of DNA fragmentation and increased caspase-2, caspase-9 and caspase-3 activities up to 4.5-, 6.0- and 5.5-fold, respectively, after 72 h of treatment. Moreover, doses of 0.1 and 1.0 microg kg(-1) violacein, administered intraperitoneally (i.p.) to EAT-bearing mice throughout the lifespan of the animals significantly inhibited tumor growth and increased survival of mice. In view of these results, a 35-day toxicity study was conducted in vivo. Complete hematology, biochemistry (ALT, AST and creatinine levels) and histopathological analysis of liver and kidney indicated that daily doses of violacein up to 1000 microg kg(-1) for 35 days are well tolerated and did not cause hematotoxicity nor renal or hepatotoxicity when administered i.p. to mice. Altogether, these results indicate that violacein causes oxidative stress and an imbalance in the antioxidant defense machinery of cells culminating in apoptotic cell death. Furthermore, this is the first report of its antitumor activity in vivo, which occurs in the absence of toxicity to

  11. Fufang Kushen injection inhibits sarcoma growth and tumor-induced hyperalgesia via TRPV1 signaling pathways

    PubMed Central

    Zhao, Zhizheng; Fan, Huiting; Higgins, Tim; Qi, Jia; Haines, Diana; Trivett, Anna; Oppenheim, Joost J.; Wei, Hou; Li, Jie; Lin, Hongsheng; Howard, O.M. Zack

    2014-01-01

    Cancer pain is a deleterious consequence of tumor growth and related inflammation. Opioids and antiinflammatory drugs provide first line treatment for cancer pain, but both are limited by side effects. Fufang Kushen injection (FKI) is GMP produced, traditional Chinese medicine used alone or with chemotherapy to reduce cancer-associated pain. FKI limited mouse sarcoma growth both in vivo and in vitro, in part, by reducing the phosphorylation of ERK and AKT kinases and BAD. FKI inhibited TRPV1 mediated capsaicin-induced ERK phosphorylation and reduced tumor-induced proinflammatory cytokine production. Thus, FKI limited cancer pain both directly by blocking TRPV1 signaling and indirectly by reducing tumor growth. PMID:25242356

  12. ERα-XPO1 Cross Talk Controls Tamoxifen Sensitivity in Tumors by Altering ERK5 Cellular Localization.

    PubMed

    Wrobel, Kinga; Zhao, Yiru Chen; Kulkoyluoglu, Eylem; Chen, Karen Lee Ann; Hieronymi, Kadriye; Holloway, Jamie; Li, Sarah; Ray, Tania; Ray, Partha Sarathi; Landesman, Yosef; Lipka, Alexander Edward; Smith, Rebecca Lee; Madak-Erdogan, Zeynep

    2016-10-01

    Most breast cancer deaths occur in women with recurrent, estrogen receptor (ER)-α(+), metastatic tumors. There is a critical need for therapeutic approaches that include novel, targetable mechanism-based strategies by which ERα (+) tumors can be resensitized to endocrine therapies. The objective of this study was to validate a group of nuclear transport genes as potential biomarkers to predict the risk of endocrine therapy failure and to evaluate the inhibition of XPO1, one of these genes as a novel means to enhance the effectiveness of endocrine therapies. Using advanced statistical methods, we found that expression levels of several of nuclear transport genes including XPO1 were associated with poor survival and predicted recurrence of tamoxifen-treated breast tumors in human breast cancer gene expression data sets. In mechanistic studies we showed that the expression of XPO1 determined the cellular localization of the key signaling proteins and the response to tamoxifen. We demonstrated that combined targeting of XPO1 and ERα in several tamoxifen-resistant cell lines and tumor xenografts with the XPO1 inhibitor, Selinexor, and tamoxifen restored tamoxifen sensitivity and prevented recurrence in vivo. The nuclear transport pathways have not previously been implicated in the development of endocrine resistance, and given the need for better strategies for selecting patients to receive endocrine modulatory reagents and improving therapy response of relapsed ERα(+) tumors, our findings show great promise for uncovering the role these pathways play in reducing cancer recurrences.

  13. ERα-XPO1 Cross Talk Controls Tamoxifen Sensitivity in Tumors by Altering ERK5 Cellular Localization

    PubMed Central

    Wrobel, Kinga; Zhao, Yiru Chen; Kulkoyluoglu, Eylem; Chen, Karen Lee Ann; Hieronymi, Kadriye; Holloway, Jamie; Li, Sarah; Ray, Tania; Ray, Partha Sarathi; Landesman, Yosef; Lipka, Alexander Edward; Smith, Rebecca Lee

    2016-01-01

    Most breast cancer deaths occur in women with recurrent, estrogen receptor (ER)-α(+), metastatic tumors. There is a critical need for therapeutic approaches that include novel, targetable mechanism-based strategies by which ERα (+) tumors can be resensitized to endocrine therapies. The objective of this study was to validate a group of nuclear transport genes as potential biomarkers to predict the risk of endocrine therapy failure and to evaluate the inhibition of XPO1, one of these genes as a novel means to enhance the effectiveness of endocrine therapies. Using advanced statistical methods, we found that expression levels of several of nuclear transport genes including XPO1 were associated with poor survival and predicted recurrence of tamoxifen-treated breast tumors in human breast cancer gene expression data sets. In mechanistic studies we showed that the expression of XPO1 determined the cellular localization of the key signaling proteins and the response to tamoxifen. We demonstrated that combined targeting of XPO1 and ERα in several tamoxifen-resistant cell lines and tumor xenografts with the XPO1 inhibitor, Selinexor, and tamoxifen restored tamoxifen sensitivity and prevented recurrence in vivo. The nuclear transport pathways have not previously been implicated in the development of endocrine resistance, and given the need for better strategies for selecting patients to receive endocrine modulatory reagents and improving therapy response of relapsed ERα(+) tumors, our findings show great promise for uncovering the role these pathways play in reducing cancer recurrences. PMID:27533791

  14. A small-molecule antagonist of CXCR4 inhibits intracranial growth of primary brain tumors

    NASA Astrophysics Data System (ADS)

    Rubin, Joshua B.; Kung, Andrew L.; Klein, Robyn S.; Chan, Jennifer A.; Sun, Yanping; Schmidt, Karl; Kieran, Mark W.; Luster, Andrew D.; Segal, Rosalind A.

    2003-11-01

    The vast majority of brain tumors in adults exhibit glial characteristics. Brain tumors in children are diverse: Many have neuronal characteristics, whereas others have glial features. Here we show that activation of the Gi protein-coupled receptor CXCR4 is critical for the growth of both malignant neuronal and glial tumors. Systemic administration of CXCR4 antagonist AMD 3100 inhibits growth of intracranial glioblastoma and medulloblastoma xenografts by increasing apoptosis and decreasing the proliferation of tumor cells. This reflects the ability of AMD 3100 to reduce the activation of extracellular signal-regulated kinases 1 and 2 and Akt, all of which are pathways downstream of CXCR4 that promote survival, proliferation, and migration. These studies (i) demonstrate that CXCR4 is critical to the progression of diverse brain malignances and (ii) provide a scientific rationale for clinical evaluation of AMD 3100 in treating both adults and children with malignant brain tumors.

  15. A small-molecule antagonist of CXCR4 inhibits intracranial growth of primary brain tumors.

    PubMed

    Rubin, Joshua B; Kung, Andrew L; Klein, Robyn S; Chan, Jennifer A; Sun, YanPing; Schmidt, Karl; Kieran, Mark W; Luster, Andrew D; Segal, Rosalind A

    2003-11-11

    The vast majority of brain tumors in adults exhibit glial characteristics. Brain tumors in children are diverse: Many have neuronal characteristics, whereas others have glial features. Here we show that activation of the Gi protein-coupled receptor CXCR4 is critical for the growth of both malignant neuronal and glial tumors. Systemic administration of CXCR4 antagonist AMD 3100 inhibits growth of intracranial glioblastoma and medulloblastoma xenografts by increasing apoptosis and decreasing the proliferation of tumor cells. This reflects the ability of AMD 3100 to reduce the activation of extracellular signal-regulated kinases 1 and 2 and Akt, all of which are pathways downstream of CXCR4 that promote survival, proliferation, and migration. These studies (i) demonstrate that CXCR4 is critical to the progression of diverse brain malignances and (ii) provide a scientific rationale for clinical evaluation of AMD 3100 in treating both adults and children with malignant brain tumors.

  16. Targeting DNA-PKcs and ATM with miR-101 Sensitizes Tumors to Radiation

    PubMed Central

    Zhang, Xiangming; Wang, Ping; Zhang, Zhaobin; Mo, Yin-Yuan; Mao, Hui; Hao, Chunhai; Olson, Jeffrey J.; Curran, Walter J.; Wang, Ya

    2010-01-01

    Background Radiotherapy kills tumor-cells by inducing DNA double strand breaks (DSBs). However, the efficient repair of tumors frequently prevents successful treatment. Therefore, identifying new practical sensitizers is an essential step towards successful radiotherapy. In this study, we tested the new hypothesis: identifying the miRNAs to target DNA DSB repair genes could be a new way for sensitizing tumors to ionizing radiation. Principal Findings Here, we chose two genes: DNA-PKcs (an essential factor for non-homologous end-joining repair) and ATM (an important checkpoint regulator for promoting homologous recombination repair) as the targets to search their regulating miRNAs. By combining the database search and the bench work, we picked out miR-101. We identified that miR-101 could efficiently target DNA-PKcs and ATM via binding to the 3′- UTR of DNA-PKcs or ATM mRNA. Up-regulating miR-101 efficiently reduced the protein levels of DNA-PKcs and ATM in these tumor cells and most importantly, sensitized the tumor cells to radiation in vitro and in vivo. Conclusions These data demonstrate for the first time that miRNAs could be used to target DNA repair genes and thus sensitize tumors to radiation. These results provide a new way for improving tumor radiotherapy. PMID:20617180

  17. Impact of Tumor Blood Flow Modulation on Tumor Sensitivity to the Bioreductive Drug Banoxantrone

    PubMed Central

    Manley, Eugene

    2013-01-01

    We investigated the hypoxia-dependent cytotoxicity of AQ4N (banoxantrone) using a panel of 13 cancer cell lines and studied its relationship to the expression of the quinone reductase DT-diaphorase (NQO1), which is widely found in cancer cells. We also investigated pharmacologic treatments that increase tumor hypoxia in vivo and their impact on AQ4N chemosensitivity in a solid tumor xenograft model. AQ4N showed ≥8-fold higher cytotoxicity under hypoxia than normoxia in cultures of 9L rat gliosarcoma and H460 human non-small-cell lung carcinoma cells but not for 11 other human cancer cell lines. DT-diaphorase protein levels and AQ4N chemosensitivity were poorly correlated across the cancer cell line panel, and AQ4N chemosensitivity was not affected by DT-diaphorase inhibitors. The vasodilator hydralazine decreased tumor perfusion and increased tumor hypoxia in 9L tumor xenografts, and to a lesser extent in H460 tumor xenografts. However, hydralazine did not increase AQ4N-dependent antitumor activity. Combination of AQ4N with the angiogenesis inhibitor axitinib, which increases 9L tumor hypoxia, transiently increased antitumor activity but with an increase in host toxicity. These findings indicate that the capacity to bioactivate AQ4N is not dependent on DT-diaphorase and is not widespread in cultured cancer cell lines. Moreover, the activation of AQ4N cytotoxicity in vivo requires tumor hypoxia that is more extensive or prolonged than can readily be achieved by vasodilation or by antiangiogenic drug treatment. PMID:23192656

  18. Inhibition by alcohols of the localization of radioactive nitrosonornicotine in sites of tumor formation

    SciTech Connect

    Waddell, W.J.; Marlowe, C.

    1983-06-01

    Oral administration of ethanol, n-butanol, or t-butanol to mice 20 minutes before injection of carbon-14-labeled nitrosonornicotine inhibited the localization of radioactivity in bronchial and salivary duct epithelium and in the liver. Localization of radioactivity in the nasal epithelium and esophagus was not significantly reduced. These alcohols therefore may selectively inhibit tumor formation in three of the five sites where this carcinogen typically acts.

  19. Direct pharmacological inhibition of β-catenin by RNA interference in tumors of diverse origin

    PubMed Central

    Ganesh, Shanthi; Koser, Martin; Cyr, Wendy; Chopda, Girish; Tao, Junyan; Shui, Xue; Ying, Bo; Chen, Dongyu; Pandya, Purva; Chipumuro, Edmond; Siddiquee, Zakir; Craig, Kevin; Lai, Chengjung; Dudek, Henryk; Monga, Satdarshan; Wang, Weimin; Brown, Bob D.; Abrams, Marc

    2016-01-01

    The Wnt/β-catenin pathway is among the most frequently altered signaling networks in human cancers. Despite decades of preclinical and clinical research, efficient therapeutic targeting of Wnt/β-catenin has been elusive. RNA interference (RNAi) technology silences genes at the mRNA level, and therefore can be applied to previously-undruggable targets. Lipid nanoparticles (LNPs) represent an elegant solution for delivery of RNAi-triggering oligonucleotides to disease-relevant tissues, but have been mostly restricted to applications in the liver. In this study, we systematically tuned the composition of a prototype LNP to enable tumor-selective delivery of a Dicer-substrate siRNA (DsiRNA) targeting CTNNB1, the gene encoding β-catenin. This formulation, termed EnCore-R, demonstrated pharmacodynamic activity in subcutaneous human tumor xenografts, orthotopic patient-derived xenograft (PDx) tumors, disseminated hematopoietic tumors, genetically induced primary liver tumors, metastatic colorectal tumors, murine metastatic melanoma. DsiRNA delivery was homogeneous in tumor sections, selective over normal liver and independent of apolipoprotein-E binding. Significant tumor growth inhibition was achieved in Wnt-dependent colorectal and hepatocellular carcinoma models, but not in Wnt-independent tumors. Finally, no evidence of accelerated blood clearance or sustained liver transaminase elevation was observed after repeated dosing in nonhuman primates. These data support further investigation to gain mechanistic insight, optimize dose regimens and identify efficacious combinations with standard-of-care therapeutics. PMID:27390343

  20. Macrophage PPARγ inhibits Gpr132 to mediate the anti-tumor effects of rosiglitazone

    PubMed Central

    Cheng, Wing Yin; Huynh, HoangDinh; Chen, Peiwen; Peña-Llopis, Samuel; Wan, Yihong

    2016-01-01

    Tumor-associated macrophage (TAM) significantly contributes to cancer progression. Human cancer is enhanced by PPARγ loss-of-function mutations, but inhibited by PPARγ agonists such as TZD diabetes drugs including rosiglitazone. However, it remains enigmatic whether and how macrophage contributes to PPARγ tumor-suppressive functions. Here we report that macrophage PPARγ deletion in mice not only exacerbates mammary tumor development but also impairs the anti-tumor effects of rosiglitazone. Mechanistically, we identify Gpr132 as a novel direct PPARγ target in macrophage whose expression is enhanced by PPARγ loss but repressed by PPARγ activation. Functionally, macrophage Gpr132 is pro-inflammatory and pro-tumor. Genetic Gpr132 deletion not only retards inflammation and cancer growth but also abrogates the anti-tumor effects of PPARγ and rosiglitazone. Pharmacological Gpr132 inhibition significantly impedes mammary tumor malignancy. These findings uncover macrophage PPARγ and Gpr132 as critical TAM modulators, new cancer therapeutic targets, and essential mediators of TZD anti-cancer effects. DOI: http://dx.doi.org/10.7554/eLife.18501.001 PMID:27692066

  1. Breast tumor oxygenation in response to carbogen intervention assessed simultaneously by three oxygen-sensitive parameters

    NASA Astrophysics Data System (ADS)

    Gu, Yueqing; Bourke, Vincent; Kim, Jae Gwan; Xia, Mengna; Constantinescu, Anca; Mason, Ralph P.; Liu, Hanli

    2003-07-01

    Three oxygen-sensitive parameters (arterial hemoglobin oxygen saturation SaO2, tumor vascular oxygenated hemoglobin concentration [HbO2], and tumor oxygen tension pO2) were measured simultaneously by three different optical techniques (pulse oximeter, near infrared spectroscopy, and FOXY) to evaluate dynamic responses of breast tumors to carbogen (5% CO2 and 95% O2) intervention. All three parameters displayed similar trends in dynamic response to carbogen challenge, but with different response times. These response times were quantified by the time constants of the exponential fitting curves, revealing the immediate and the fastest response from the arterial SaO2, followed by changes in global tumor vascular [HbO2], and delayed responses for pO2. The consistency of the three oxygen-sensitive parameters demonstrated the ability of NIRS to monitor therapeutic interventions for rat breast tumors in-vivo in real time.

  2. Dual EGFR/HER2 inhibition sensitizes prostate cancer cells to androgen withdrawal by suppressing ErbB3

    PubMed Central

    Chen, Liqun; Mooso, Benjamin A.; Jathal, Maitreyee K.; Madhav, Anisha; Johnson, Sherra D.; van Spyk, Elyse; Mikhailova, Margarita; Ripoll, Alexandra Zierenberg; Xue, Lingru; Vinall, Ruth L.; deVere White, Ralph W; Ghosh, Paramita M.

    2011-01-01

    Purpose Patients with recurrent prostate cancer (PCa) are commonly treated with androgen withdrawal therapy (AWT); however, almost all patients eventually progress to castration resistant prostate cancer (CRPC), indicating failure of AWT to eliminate androgen-sensitive PCa. The overall goal of these studies is to determine whether dual inhibition of the receptor tyrosine kinases EGFR and HER2 would prolong the effectiveness of this treatment in PCa. Experimental Design We used androgen-dependent LNCaP cells and its CRPC sublines LNCaP-AI and C4-2. Additional data were collected in pRNS-1-1 cells stably expressing a mutant androgen receptor (AR-T877A), and in nude mice harboring CWR22 tumors. Studies utilized EGFR inhibitors erlotinib and AG1478, and HER2 inhibitors trastuzumab and AG879. Results Dual EGFR/HER2 inhibition induced apoptosis selectively in androgen-sensitive PCa cells undergoing AWT, but not in the presence of androgens, or in CRPC cells. We show that AWT alone failed to induce significant apoptosis in androgen-dependent cells, due to AWT-induced increase in HER2 and ErbB3, which promoted survival by increasing Akt phosphorylation. AWT-induced ErbB3 stabilized the AR and stimulated PSA, while it was inactivated only by inhibition of both its dimerization partners EGFR and HER2 (PCa cells do not express ErbB4); but not the inhibition of any one receptor alone, explaining the success of dual EGFR/HER2 inhibition in sensitizing androgen-dependent cells to AWT. The effectiveness of the inhibitors in suppressing growth correlated with its ability to prevent Akt phosphorylation. Conclusions These studies indicate that dual EGFR/HER2 inhibition, administered together with AWT; sensitize PCa cells to apoptosis during AWT. PMID:21844010

  3. Cytosolic PhospholipaseA2 Inhibition with PLA-695 Radiosensitizes Tumors in Lung Cancer Animal Models

    PubMed Central

    Ferraro, Daniel J.; Kotipatruni, Rama P.; Bhave, Sandeep R.; Jaboin, Jerry J.; Hallahan, Dennis E.

    2013-01-01

    Lung cancer remains the leading cause of cancer deaths in the United States and the rest of the world. The advent of molecularly directed therapies holds promise for improvement in therapeutic efficacy. Cytosolic phospholipase A2 (cPLA2) is associated with tumor progression and radioresistance in mouse tumor models. Utilizing the cPLA2 specific inhibitor PLA-695, we determined if cPLA2 inhibition radiosensitizes non small cell lung cancer (NSCLC) cells and tumors. Treatment with PLA-695 attenuated radiation induced increases of phospho-ERK and phospho-Akt in endothelial cells. NSCLC cells (LLC and A549) co-cultured with endothelial cells (bEND3 and HUVEC) and pre-treated with PLA-695 showed radiosensitization. PLA-695 in combination with irradiation (IR) significantly reduced migration and proliferation in endothelial cells (HUVEC & bEND3) and induced cell death and attenuated invasion by tumor cells (LLC &A549). In a heterotopic tumor model, the combination of PLA-695 and radiation delayed growth in both LLC and A549 tumors. LLC and A549 tumors treated with a combination of PLA-695 and radiation displayed reduced tumor vasculature. In a dorsal skin fold model of LLC tumors, inhibition of cPLA2 in combination with radiation led to enhanced destruction of tumor blood vessels. The anti-angiogenic effects of PLA-695 and its enhancement of the efficacy of radiotherapy in mouse models of NSCLC suggest that clinical trials for its capacity to improve radiotherapy outcomes are warranted. PMID:23894523

  4. Cytosolic phospholipaseA2 inhibition with PLA-695 radiosensitizes tumors in lung cancer animal models.

    PubMed

    Thotala, Dinesh; Craft, Jeffrey M; Ferraro, Daniel J; Kotipatruni, Rama P; Bhave, Sandeep R; Jaboin, Jerry J; Hallahan, Dennis E

    2013-01-01

    Lung cancer remains the leading cause of cancer deaths in the United States and the rest of the world. The advent of molecularly directed therapies holds promise for improvement in therapeutic efficacy. Cytosolic phospholipase A2 (cPLA2) is associated with tumor progression and radioresistance in mouse tumor models. Utilizing the cPLA2 specific inhibitor PLA-695, we determined if cPLA2 inhibition radiosensitizes non small cell lung cancer (NSCLC) cells and tumors. Treatment with PLA-695 attenuated radiation induced increases of phospho-ERK and phospho-Akt in endothelial cells. NSCLC cells (LLC and A549) co-cultured with endothelial cells (bEND3 and HUVEC) and pre-treated with PLA-695 showed radiosensitization. PLA-695 in combination with irradiation (IR) significantly reduced migration and proliferation in endothelial cells (HUVEC & bEND3) and induced cell death and attenuated invasion by tumor cells (LLC &A549). In a heterotopic tumor model, the combination of PLA-695 and radiation delayed growth in both LLC and A549 tumors. LLC and A549 tumors treated with a combination of PLA-695 and radiation displayed reduced tumor vasculature. In a dorsal skin fold model of LLC tumors, inhibition of cPLA2 in combination with radiation led to enhanced destruction of tumor blood vessels. The anti-angiogenic effects of PLA-695 and its enhancement of the efficacy of radiotherapy in mouse models of NSCLC suggest that clinical trials for its capacity to improve radiotherapy outcomes are warranted.

  5. Inhibition of solid tumor growth by gene transfer of VEGF receptor-1 mutants.

    PubMed

    Heidenreich, Regina; Machein, Marcia; Nicolaus, Anke; Hilbig, Andreas; Wild, Carola; Clauss, Matthias; Plate, Karl H; Breier, Georg

    2004-09-01

    Vascular endothelial growth factor (VEGF) and the high-affinity VEGF receptor Flk-1/KDR (VEGFR-2) are key regulators of tumor angiogenesis. Strategies to block VEGF/VEGFR-2 signaling were successfully used to inhibit experimental tumor growth and indicated that VEGFR-2 is the main signaling VEGF receptor in proliferating tumor endothelium. Here, we investigated the role of the VEGF receptor-1 (VEGFR-1/Flt-1) in the vascularization of 2 different experimental tumors in vivo. VEGFR-1 mutants were generated that lack the intracellular tyrosine kinase domain. Retrovirus-mediated gene transfer of the VEGFR-1 mutants led to a strong reduction of tumor growth and angiogenesis in xenografted C6 glioma and in syngeneic BFS-1 fibrosarcoma. Histological analysis of the inhibited fibrosarcoma revealed reduced vascular density, decreased tumor cell proliferation as well as increased tumor cell apoptosis and the formation of necrosis. The retroviral gene transfer of the full length VEGFR-1 also caused a significant reduction of tumor growth in both models. The inhibitory effects of the VEGFR-1 mutants and the full length VEGFR-1 in BFS-1 fibrosarcoma were mediated through host tumor endothelial cells because the BFS-1 fibrosarcoma cells were not infected by the retrovirus. The formation of heterodimers between VEGFR-2 and full length or truncated VEGFR-1 was observed in vitro and might contribute to the growth inhibitory effect by modulating distinct signal transduction pathways. The results of our study underline the central role of the VEGF/VEGFR-1 signaling system in tumor angiogenesis and demonstrate that VEGFR-1 can serve as a target for anti-angiogenic gene therapy.

  6. Chloroquine alleviates etoposide-induced centrosome amplification by inhibiting CDK2 in adrenocortical tumor cells

    PubMed Central

    Chen, T-Y; Syu, J-S; Lin, T-C; Cheng, H-l; Lu, F-l; Wang, C-Y

    2015-01-01

    The antitumor drug etoposide (ETO) is widely used in treating several cancers, including adrenocortical tumor (ACT). However, when used at sublethal doses, tumor cells still survive and are more susceptible to the recurring tumor due to centrosome amplification. Here, we checked the effect of sublethal dose of ETO in ACT cells. Sublethal dose of ETO treatment did not induce cell death but arrested the ACT cells in G2/M phase. This resulted in centrosome amplification and aberrant mitotic spindle formation leading to genomic instability and cellular senescence. Under such conditions, Chk2, cyclin A/CDK2 and ERK1/2 were aberrantly activated. Pharmacological inactivation of Chk2, CDK2 or ERK1/2 or depletion of CDK2 or Chk2 inhibited the centrosome amplification in ETO-treated ACT cells. In addition, autophagy was activated by ETO and was required for ACT cell survival. Chloroquine, the autophagy inhibitor, reduced ACT cell growth and inhibited ETO-induced centrosome amplification. Chloroquine alleviated CDK2 and ERK, but not Chk2, activation and thus inhibited centrosome amplification in either ETO- or hydroxyurea-treated ACT cells. In addition, chloroquine also inhibited centrosome amplification in osteosarcoma U2OS cell lines when treated with ETO or hydroxyurea. In summary, we have demonstrated that chloroquine inhibited ACT cell growth and alleviated DNA damage-induced centrosome amplification by inhibiting CDK2 and ERK activity, thus preventing genomic instability and recurrence of ACT. PMID:26690546

  7. Luteolin inhibits the Nrf2 signaling pathway and tumor growth in vivo

    SciTech Connect

    Chian, Song; Thapa, Ruby; Chi, Zhexu; Wang, Xiu Jun; Tang, Xiuwen

    2014-05-16

    Highlights: • Luteolin inhibits the Nrf2 pathway in mouse liver and in xenografted tumors. • Luteolin markedly inhibits the growth of xenograft tumors. • Luteolin enhances the anti-cancer effect of cisplatin in mice in vivo. • Luteolin could serve as an adjuvant in the chemotherapy of NSCLC. - Abstract: Nuclear factor erythroid 2-related factor 2 (Nrf2) is over-expressed in many types of tumor, promotes tumor growth, and confers resistance to anticancer therapy. Hence, Nrf2 is regarded as a novel therapeutic target in cancer. Previously, we reported that luteolin is a strong inhibitor of Nrf2 in vitro. Here, we showed that luteolin reduced the constitutive expression of NAD(P)H quinone oxidoreductase 1 in mouse liver in a time- and dose-dependent manner. Further, luteolin inhibited the expression of antioxidant enzymes and glutathione transferases, decreasing the reduced glutathione in the liver of wild-type mice under both constitutive and butylated hydroxyanisole-induced conditions. In contrast, such distinct responses were not detected in Nrf2{sup −/−} mice. In addition, oral administration of luteolin, either alone or combined with intraperitoneal injection of the cytotoxic drug cisplatin, greatly inhibited the growth of xenograft tumors from non-small-cell lung cancer (NSCLC) cell line A549 cells grown subcutaneously in athymic nude mice. Cell proliferation, the expression of Nrf2, and antioxidant enzymes were all reduced in tumor xenograft tissues. Furthermore, luteolin enhanced the anti-cancer effect of cisplatin. Together, our findings demonstrated that luteolin inhibits the Nrf2 pathway in vivo and can serve as an adjuvant in the chemotherapy of NSCLC.

  8. Inhibition of mammary tumor growth and metastases to bone and liver by dietary grape polyphenols.

    PubMed

    Castillo-Pichardo, Linette; Martínez-Montemayor, Michelle M; Martínez, Joel E; Wall, Kristin M; Cubano, Luis A; Dharmawardhane, Suranganie

    2009-01-01

    The cancer preventive properties of grape products such as red wine have been attributed to polyphenols enriched in red wine. However, much of the studies on cancer preventive mechanisms of grape polyphenols have been conducted with individual compounds at concentrations too high to be achieved via dietary consumption. We recently reported that combined grape polyphenols at physiologically relevant concentrations are more effective than individual compounds at inhibition of ERalpha(-), ERbeta(+) MDA-MB-231 breast cancer cell proliferation, cell cycle progression, and primary mammary tumor growth (Schlachterman et al., Transl Oncol 1:19-27, 2008). Herein, we show that combined grape polyphenols induce apoptosis and are more effective than individual resveratrol, quercetin, or catechin at inhibition of cell proliferation, cell cycle progression, and cell migration in the highly metastatic ER (-) MDA-MB-435 cell line. The combined effect of dietary grape polyphenols (5 mg/kg each resveratrol, quercetin, and catechin) was tested on progression of mammary tumors in nude mice created from green fluorescent protein-tagged MDA-MB-435 bone metastatic variant. Fluorescence image analysis of primary tumor growth demonstrated a statistically significant decrease in tumor area by dietary grape polyphenols. Molecular analysis of excised tumors demonstrated that reduced mammary tumor growth may be due to upregulation of FOXO1 (forkhead box O1) and NFKBIA (IkappaBalpha), thus activating apoptosis and potentially inhibiting NfkappaB (nuclear factor kappaB) activity. Image analysis of distant organs for metastases demonstrated that grape polyphenols reduced metastasis especially to liver and bone. Overall, these results indicate that combined dietary grape polyphenols are effective at inhibition of mammary tumor growth and site-specific metastasis.

  9. Ursolic acid inhibits tumor angiogenesis and induces apoptosis through mitochondrial-dependent pathway in Ehrlich ascites carcinoma tumor.

    PubMed

    Saraswati, Sarita; Agrawal, S S; Alhaider, Abdulqader A

    2013-11-25

    Ursolic acid (UA) is a pentacyclic triterpene naturally occurring in many plant foods. In the present study, we investigated anti-cancer activity of UA in vivo in Ehrlich ascites carcinoma (EAC) tumor. 15 × 10(6) EAC cells were implanted intraperitoneally (i.p., ascitic tumor) and subcutaneous (s.c., solid tumor) in Swiss albino mice. Mice with established tumors received UA i.p. at 25, 50 and 100mg/kg bw for 14 d in ascitic and 100mg/kg bw in solid tumor for 30 d. On day 15, blood samples were collected for hematological assessment of hemoglobin (Hb%), RBCs, WBCs and PCV. Tumor volume, cell viability, angiogenic, anti-angiogenic, anti-inflammatory factors and antioxidant parameters were determined. Immunohistochemistry analysis for VEGF, iNOS, CD31, caspase-3 and Bax were also performed. UA significantly inhibited tumor growth, cell viability, in both ascites and solid tumor model in vivo (p<0.001). The anti-angiogenic effects were accompanied with decreased VEGF, iNOS, TNF-α and increased IL-12 levels. UA at 100mg/kg bw dose significantly increased SOD and CAT activity (p<0.01). GSH and TBARS were increased as compared to control group (p<0.001). Furthermore, UA increased total RBCs, WBCs as well as Hb% significantly (p<0.05) compared to cyclophosphamide (CP). Histopathological examination of tumor cells in the treated group demonstrated signs of apoptosis with chromatin condensation and cell shrinkage. Decreased peritoneal angiogenesis showed the anti-angiogenic potential. UA downregulated VEGF & iNOS expression whereas bax and caspase-3 expressions were upregulated suggesting drug induced tumor cell apoptosis through activating the pro-apoptotic bcl-2 family and caspase-3 and downregulation of VEGF. The present study sheds light on the potent antitumor property of the UA and can be extended further to develop therapeutic protocols for treatment of cancer. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  10. Oroxin B selectively induces tumor-suppressive ER stress and concurrently inhibits tumor-adaptive ER stress in B-lymphoma cells for effective anti-lymphoma therapy.

    PubMed

    Yang, Ping; Fu, Shilong; Cao, Zhifei; Liao, Huaidong; Huo, Zihe; Pan, Yanyan; Zhang, Gaochuan; Gao, Aidi; Zhou, Quansheng

    2015-10-15

    Cancer cells have both tumor-adaptive and -suppressive endoplasmic reticulum (ER) stress machineries that determine cell fate. In malignant tumors including lymphoma, constant activation of tumor-adaptive ER stress and concurrent reduction of tumor-suppressive ER stress favors cancer cell proliferation and tumor growth. Current ER stress-based anti-tumor drugs typically activate both tumor-adaptive and -suppressive ER stresses, resulting in low anti-cancer efficacy; hence, selective induction of tumor-suppressive ER stress and inhibition of tumor-adaptive ER stress are new strategies for novel anti-cancer drug discovery. Thus far, specific tumor-suppressive ER stress therapeutics have remained absent in clinical settings. In this study, we explored unique tumor-suppressive ER stress agents from the traditional Chinese medicinal herb Oroxylum indicum, and found that a small molecule oroxin B selectively induced tumor-suppressive ER stress in malignant lymphoma cells, but not in normal cells, effectively inhibited lymphoma growth in vivo, and significantly prolonged overall survival of lymphoma-xenografted mice without obvious toxicity. Mechanistic studies have revealed that the expression of key tumor-adaptive ER-stress gene GRP78 was notably suppressed by oroxin B via down-regulation of up-stream key signaling protein ATF6, while tumor-suppressive ER stress master gene DDIT3 was strikingly activated through activating the MKK3-p38 signaling pathway, correcting the imbalance between tumor-suppressive DDIT3 and tumor-adaptive GRP78 in lymphoma. Together, selective induction of unique tumor-suppressive ER stress and concurrent inhibition of tumor-adaptive ER stress in malignant lymphoma are new and feasible approaches for novel anti-lymphoma drug discovery and anti-lymphoma therapy.

  11. Drugs Which Inhibit Osteoclast Function Suppress Tumor Growth through Calcium Reduction in Bone

    PubMed Central

    Li, Xin; Liao, Jinhui; Park, Serk In; Koh, Amy J; Sadler, William D; Pienta, Kenneth J; Rosol, Thomas J; McCauley, Laurie K

    2011-01-01

    Prostate carcinoma frequently metastasizes to bone where the microenvironment facilitates its growth. Inhibition of bone resorption is effective in reducing tumor burden and bone destruction in prostate cancer. However, whether drugs that inhibit osteoclast function inhibit tumor growth independent of inhibition of bone resorption is unclear. Calcium is released during bone resorption and the calcium sensing receptor is an important regulator of cancer cell proliferation. The goal of this investigation was to elucidate the role of calcium released during bone resorption and to determine the impact of drugs which suppress bone resorption on tumor growth in bone. To compare tumor growth in a skeletal versus non-skeletal site, equal numbers of canine prostate cancer cells expressing luciferase (ACE-1luc) prostate cancer cells were inoculated into a simple collagen matrix, neonatal mouse vertebrae (vossicles), human de-proteinized bone, or a mineralized collagen matrix. Implants were placed subcutaneously into athymic mice. Luciferase activity was used to track tumor growth weekly and at one month tumors were dissected for histologic analysis. Luciferase activity and tumor size were greater in vossicles, de-proteinized bone and mineralized collagen matrix versus non-mineralized collagen implants. The human osteoblastic prostate carcinoma cell line C4-2b also grew better in a mineral rich environment with a greater proliferation of C4-2b cells reflected by Ki-67 staining. Zoledronic acid (ZA), a bisphosphonate, and recombinant OPG-Fc, a RANKL inhibitor, were administered to mice bearing vertebral implants (vossicles) containing ACE-1 osteoblastic prostate cancer cells. Vossicles or collagen matrices were seeded with ACE-1luc cells subcutaneously in athymic mice (2 vossicles, 2 collagen implants/mouse). Mice received ZA (5μg/mouse, twice/week), (OPG-Fc at 10mg/kg, 3 times/week) or vehicle, and luciferase activity was measured weekly. Histologic analysis of the tumors

  12. Ursolic acid sensitized colon cancer cells to chemotherapy under hypoxia by inhibiting MDR1 through HIF-1α*

    PubMed Central

    Shan, Jian-zhen; Xuan, Yan-yan; Zhang, Qi; Huang, Jian-jin

    2016-01-01

    Objective: To explore the efficacy of ursolic acid in sensitizing colon cancer cells to chemotherapy under hypoxia and its underlying mechanisms. Methods: Three colon cancer cell lines (RKO, LoVo, and SW480) were used as in vitro models. 5-Fluorouracil (5-FU) and oxaliplatin were used as chemotherapeutic drugs. Cell viability and apoptosis were tested to evaluate the sensitivity of colon cancer cells to chemotherapy. The transcription and expression levels of hypoxia-inducible factor-1α (HIF-1α), multidrug resistance gene 1 (MDR1), and vascular endothelial growth factors (VEGF) were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and immunoblotting. Cycloheximide and MG132 were used to inhibit protein synthesis and degradation, respectively. In vitro tube formation assay was used to evaluate angiogenesis. Results: We demonstrated the chemosensitizing effects of ursolic acid with 5-FU and oxaliplatin in three colon cancer cell lines under hypoxia. This effect was correlated to its inhibition of MDR1 through HIF-1α. Moreover, ursolic acid was capable of inhibiting HIF-1α accumulation with little effects on its constitutional expression in normoxia. In addition, ursolic acid also down-regulated VEGF and inhibited tumor angiogenesis. Conclusions: Ursolic acid exerted chemosensitizing effects in colon cancer cells under hypoxia by inhibiting HIF-1α accumulation and the subsequent expression of the MDR1 and VEGF. PMID:27604859

  13. Dietary rice component, Oryzanol, inhibits tumor growth in tumor-bearing Mice

    USDA-ARS?s Scientific Manuscript database

    Scope: We investigated the effects of rice bran and components on tumor growth in mice. Methods and results: Mice fed standard diets supplemented with rice bran, '-oryzanol, Ricetrienol®, ferulic acid, or phytic acid for 2 weeks were inoculated with CT-26 colon cancer cells and fed the same diet fo...

  14. Timosaponin AIII is preferentially cytotoxic to tumor cells through inhibition of mTOR and induction of ER stress.

    PubMed

    King, Frank W; Fong, Sylvia; Griffin, Chandi; Shoemaker, Mark; Staub, Rick; Zhang, Yan-Ling; Cohen, Isaac; Shtivelman, Emma

    2009-09-30

    The aqueous extract of Anemarrhena asphodeloides (BN108) induces apoptosis in various cancer cell lines but is significantly less cytotoxic in non-transformed cells. Chemical fractionation of BN108 showed that its cytotoxicity is associated with timosaponins, steroidal saponins of coprostane type. Timosaponin BII (TBII) is a major saponin in BN108, but it shows little cytotoxicity. A much less abundant TAIII induces cell death in tumor cells but not in normal cells, reproducing the selectivity of the total extract BN108. Glycosidase treatment, by removing the extra sugar moiety in TBII, converts it to TAIII and confers cytotoxic activity. Analysis of the mechanisms of death induced by TAIII revealed activation of two distinct pro-apoptotic pathways: first, inhibition of mTORC1 manifested in much reduced phosphorylation of mTORC1 targets; second, induction of endoplasmic reticulum stress culminating in phosphorylation of eIF2alpha and activation of caspase 4. These pro-apoptotic pathways are activated by TAIII selectively in tumor cells but not in normal cells. Both pathways play a causative role in TAIII cytotoxicity, as restoration of either mTOR activity or relief of ER stress alone offer only partial protection from TAIII. Inhibition of mTORC1 and induction of ER stress apparently contribute to the induction of the previously reported autophagic response in TAIII-treated cells. TAIII induced autophagy plays a protective role in TAIII induced death signaling, and failure to mount autophagic response is associated with heightened sensitivity to TAIII induced apoptosis. The multiple death-promoting and apparently tumor-selective responses to TAIII, its ability to inhibit mTORC1, and the possibility of further enhancing its cytotoxicity by pharmacological inhibition of autophagy, make TAIII an attractive candidate for development as a cancer therapeutic agent.

  15. Blocking Fibroblast Growth Factor Receptor Signaling Inhibits Tumor Growth, Lymphangiogenesis, and Metastasis

    PubMed Central

    Larrieu-Lahargue, Frédéric; Welm, Alana L.; Bouchecareilh, Marion; Alitalo, Kari; Li, Dean Y.; Bikfalvi, Andreas; Auguste, Patrick

    2012-01-01

    Fibroblast Growth Factor receptor (FGFR) activity plays crucial roles in tumor growth and patient survival. However, FGF (Fibroblast Growth Factor) signaling as a target for cancer therapy has been under-investigated compared to other receptor tyrosine kinases. Here, we studied the effect of FGFR signaling inhibition on tumor growth, metastasis and lymphangiogenesis by expressing a dominant negative FGFR (FGFR-2DN) in an orthotopic mouse mammary 66c14 carcinoma model. We show that FGFR-2DN-expressing 66c14 cells proliferate in vitro slower than controls. 66c14 tumor outgrowth and lung metastatic foci are reduced in mice implanted with FGFR-2DN-expressing cells, which also exhibited better overall survival. We found 66c14 cells in the lumen of tumor lymphatic vessels and in lymph nodes. FGFR-2DN-expressing tumors exhibited a decrease in VEGFR-3 (Vascular Endothelial Growth Factor Receptor-3) or podoplanin-positive lymphatic vessels, an increase in isolated intratumoral lymphatic endothelial cells and a reduction in VEGF-C (Vascular Endothelial Growth Factor-C) mRNA expression. FGFs may act in an autocrine manner as the inhibition of FGFR signaling in tumor cells suppresses VEGF-C expression in a COX-2 (cyclooxygenase-2) or HIF1-α (hypoxia-inducible factor-1 α) independent manner. FGFs may also act in a paracrine manner on tumor lymphatics by inducing expression of pro-lymphangiogenic molecules such as VEGFR-3, integrin α9, prox1 and netrin-1. Finally, in vitro lymphangiogenesis is impeded in the presence of FGFR-2DN 66c14 cells. These data confirm that both FGF and VEGF signaling are necessary for the maintenance of vascular morphogenesis and provide evidence that targeting FGFR signaling may be an interesting approach to inhibit tumor lymphangiogenesis and metastatic spread. PMID:22761819

  16. TRA-8 anti-DR5 monoclonal antibody and gemcitabine induce apoptosis and inhibit radiologically validated orthotopic pancreatic tumor growth.

    PubMed

    Derosier, Leo Christopher; Vickers, Selwyn M; Zinn, Kurt R; Huang, Zhi; Wang, Wenquan; Grizzle, William E; Sellers, Jeffrey; Stockard, Cecil R; Zhou, Tong; Oliver, Patsy G; Arnoletti, Pablo; Lobuglio, Albert F; Buchsbaum, Donald J

    2007-12-01

    To evaluate agonistic TRA-8 monoclonal antibody to human death receptor 5 (DR5) and gemcitabine in vitro and in an orthotopic pancreatic cancer model. Pancreatic cancer cell lines were screened for DR5 expression, cytotoxicity, and apoptosis induced by TRA-8, gemcitabine, or gemcitabine and TRA-8. An orthotopic model of pancreatic cancer was established in severe combined immunodeficient mice. Mice were treated with TRA-8, gemcitabine, or a combination for one or two cycles of therapy. Tumor growth (ultrasound) and survival were analyzed. All five pancreatic cancer cell lines showed DR5 protein expression and varying sensitivity to TRA-8-mediated cytotoxicity. MIA PaCa-2 cells were very sensitive to TRA-8, moderately resistant to gemcitabine, with additive cytotoxicity to the combination. S2-VP10 cells were resistant to TRA-8 and sensitive to gemcitabine with synergistic sensitivity to the combination. Combination treatment in vitro produced enhanced caspase-3 and caspase-8 activation. A single cycle of therapy produced comparable efficacy for single-agent TRA-8 and the combination of TRA-8 and gemcitabine, with significant reduction in tumor size and prolonged survival compared with gemcitabine alone or control animals. With two cycles of therapy, TRA-8 and combination therapy produced enhanced inhibition of tumor growth compared with single-agent gemcitabine or untreated animals. However, the combination regimen showed enhanced survival as compared with single-agent TRA-8. Pancreatic cancer cell lines express varying levels of DR5 and differ in their sensitivity to TRA-8 and gemcitabine-induced cytotoxicity. TRA-8 with two cycles of gemcitabine therapy produced the best overall survival.

  17. Gemcitabine sensitization by Chk1 inhibition correlates with inhibition of a Rad51 DNA damage response in pancreatic cancer cells1

    PubMed Central

    Parsels, Leslie A.; Morgan, Meredith A.; Tanska, Daria M.; Parsels, Joshua D.; Palmer, Brian D.; Booth, R. John; Denny, William A.; Canman, Christine E.; Kraker, Alan J.; Lawrence, Theodore S.; Maybaum, Jonathan

    2009-01-01

    The protein kinase Chk1 has been implicated as a key regulator of cell cycle progression and DNA repair and inhibitors of Chk1 (e.g., UCN-01, EXEL-9844) potentiate the cytotoxic actions of chemotherapeutic drugs in tumor cells. We have examined the ability of PD-321852, a small-molecule Chk1 inhibitor, to potentiate gemcitabine (Gem)-induced clonogenic death in a panel of pancreatic cancer cell lines, and evaluated the relationship between endpoints associated with Chk1 inhibition and chemosensitization. Gem chemosensitization by minimally-toxic concentrations of PD-321852 ranged from minimal (< 3 fold change in survival) in Panc1 cells, to over 30-fold in MiaPaCa2 cells. PD-321852 inhibited Chk1 in all cell lines, as evidenced by stabilization of Cdc25A, and, in combination with Gem, a synergistic loss of Chk1 protein was observed in the more sensitized cell lines. Gem chemosensitization, however, did not correlate with abrogation of the S/M or G2/M checkpoint; PD-321852 did not induce premature mitotic entry in Gem-treated BxPC3 or M-Panc96 cells, which were sensitized to Gem 6.2- and 4.6-fold, respectively. In the more sensitized cells lines, PD-321852 not only inhibited Gem-induced Rad51 focus formation and the recovery from Gem-induced replication stress, as evidenced by persistence of γ-H2AX, but also depleted these cells of Rad51 protein. Our data suggest the inhibition of this Chk1-mediated Rad51 response to Gem-induced replication stress is an important factor in determining Gem chemosensitization by Chk1 inhibition in pancreatic cancer cells. PMID:19139112

  18. Xanthii Fructus inhibits allergic response in the ovalbumin-sensitized mouse allergic rhinitis model

    PubMed Central

    Gwak, Nam-Gil; Kim, Eun-Young; Lee, Bina; Kim, Jae-Hyun; Im, Yong-Seok; Lee, Ka-Yeon; Jun-Kum, Chang; Kim, Ho-Seok; Cho, Hyun-Joo; Jung, Hyuk-Sang; Sohn, Youngjoo

    2015-01-01

    Background: Xanthii Fructus (XF) is widely used in traditional anti-bacterial and anti-inflammatory Asian medicine. Allergic rhinitis is a common inflammatory disease characterized by markedly increased levels of anti-inflammatory factors and the recruitment of inflammatory cells into the nasal mucosa. We investigated the effects of XF in the allergen-induced rhinitis model. Materials and Methods: Following ovalbumin (OVA)/alum intraperitoneal injection on days 0, 7 and 14, the BALB/c mice (albino, laboratory-bred strain of the house mice) were challenged intranasally with OVA for 10 days a week after the last sensitization. The number of sneezes was recorded for 10 days; additionally, the levels of cytokines, histamine, immunoglobulin E (IgE) and OVA-specific serum IgE were estimated. Eosinophil infiltration, thickness of nasal mucosa and expression of caspase-1 were determined by immunohistochemistry. We also evaluated the effect of XF on the phosphorylation of nuclear factor kappa-B (NF-κB) and inhibitor of nuclear factor kappa B-alpha (IκB-α) in human mast cell-1 (HMC-1), by Western blotting. Results: The administration of XF significantly decreased sneezing and the serum levels of histamine, IgE, OVA-specific IgE, and cytokines such as tumor necrosis factor-alpha (TNF-α), interleukine-1 beta (IL-1β), IL-5, IL-6, monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2). XF inhibited the changes in thickness of the nasal septum, influx of eosinophils and expression of capase-1. In addition, XF inhibited the phosphorylation of IκB-α and NF-κB in phorbol-myristate-acetate plus calcium ionophore A23187 (A23187) stimulated HMC-1. Conclusion: This study suggests that XF acts a potent anti-allergic drug which alleviates the allergic responses in ovalbumin-sensitized mouse allergic rhinitis model. PMID:26664025

  19. WEE1 inhibition sensitizes basal breast cancer cells to TRAIL-induced apoptosis

    PubMed Central

    Garimella, Sireesha V; Rocca, Andrea; Lipkowitz, Stanley

    2011-01-01

    Tumor Necrosis Factor (TNF)-Related Apoptosis Inducing Ligand (TRAIL) is a member of the TNF super family and has been shown to induce apoptosis in many cancer cell lines but not in normal cells. Breast cancers can be divided into different subgroups based on the expression of estrogen and progesterone receptors, HER-2 amplification, or the lack of these three markers (known as triple-negative or basal-type breast cancer). Our group and others have shown previously that triple-negative breast cancer cell lines are sensitive to TRAIL while others are relatively resistant. In an earlier study, we reported that inhibition of WEE1, a cell cycle checkpoint regulator, causes increased cell death in breast cancer cell lines. In this study, we tested the effects of WEE1 inhibition on TRAIL-mediated apoptosis in breast cancer cell lines. Pre-treatment with WEE1 inhibitor or knockdown of WEE1 increased the toxicity of TRAIL in the basal/triple-negative breast cancer cell lines compared to WEE1 inhibitor or TRAIL treatment alone. The enhanced cell death is attributed to increased surface expression of death receptors, increased caspase activation which could be blocked by the pan-caspase inhibitor, Z-VAD-FMK, thereby rescuing cells from caspase-mediated apoptosis. The cell death was initiated primarily by caspase-8 since knockdown of caspase-8 and not of any other initiator caspases (i.e, caspase-2, -9, or -10) rescued cells from WEE1 inhibitor sensitized TRAIL-induced cell death. Taken together, the data suggest that the combination of WEE1 inhibitor and TRAIL could provide a novel combination for the treatment of basal/triple-negative breast cancer. PMID:22112940

  20. Nitric oxide synthesis contributes to inhibition of graft-versus-tumor-effects against intraperitoneal Meth A tumor.

    PubMed

    Song, Eun-Kee; Lee, Na-Ri; Sohn, Myung-Hee; Kwak, Jae-Yong; Yim, Chang-Yeol

    2004-08-01

    The role of nitric oxide (NO) in graft-versus-tumor-effect (GVT) was evaluated in the present study. GVT was induced by intravenous injection of C57BL/6J (H-2b) mouse splenocytes to {C57BL/6J (H-2b) x BALB/c (H-2d)} F1 mice bearing Meth A (H-2d) ascites tumors. Induction of GVT increased nitrite production and expression of inducible NO synthase by ascites cells. The increased nitrite production was inhibited by NG-monomethyl-L-arginine (MLA). Experiments employing immunomagnetic depletion of Mac-1+ cells from ascites indicated that macrophages were a major cellular source of the nitrite production. Interferon-gamma levels were increased in both serum and ascites fluid during GVT. Induction of GVT prolonged survival of ascites-bearing mice, and increased urinary nitrate excretion. MLA administration inhibited GVT-induced increase in urinary nitrate excretion, and further prolonged GVT-induced increase in survival. These results indicate that NO synthesis is induced in tumors during GVT, and the NO acts as an inhibitor of GVT.

  1. Novel Histone Deacetylase Inhibitors with Enhanced Enzymatic Inhibition Effects and Potent in vitro and in vivo Anti-tumor Activities

    PubMed Central

    Zhang, Lei; Zhang, Yingjie; Chou, C. James; Inks, Elizabeth S.; Wang, Xuejian; Li, Xiaoguang; Hou, Jinning; Xu, Wenfang

    2014-01-01

    In the present work, a series of small molecules were designed and synthesized based on structural optimization. Significant improvement in the enzymatic inhibition activity of the synthesized compounds was discovered. Moreover, tested compounds have moderate preference for class I HDACs over HDAC6 proved by enzymatic selectivity assay. The in vitro anti-proliferation assay reveals that representative compounds can selectively inhibit the growth of the non-solid lymphomatous cells and leukemic cells such as U937, K562 and HL60 cell lines. In the in vivo anti-tumor assay, molecule D17 showed better performance than SAHA in inhibition of U937 tumor growth. The western blot analysis revealed that representative molecules can block the function of both class I HDACs and HDAC6. More importantly, our western blot results revealed that the levels of some oncogenic proteins (p-Akt in the PI3K/AKT/mTOR signal pathway, c-Raf and p-Erk in the MAPK signal pathway) were dramatically down-regulated by our compounds in U937 cell line rather than MDA-MB-231 cells. This cellular mechanism difference might be an important reason why U937 cell line was more sensitive to our HDACs inhibitors than MDA-MB-231 cell line. PMID:24227760

  2. Tumor Necrosis Factor Inhibits Glucocorticoid Receptor Function in Mice

    PubMed Central

    Van Bogaert, Tom; Vandevyver, Sofie; Dejager, Lien; Van Hauwermeiren, Filip; Pinheiro, Iris; Petta, Ioanna; Engblom, David; Kleyman, Anna; Schütz, Günther; Tuckermann, Jan; Libert, Claude

    2011-01-01

    As glucocorticoid resistance (GCR) and the concomitant burden pose a worldwide problem, there is an urgent need for a more effective glucocorticoid therapy, for which insights into the molecular mechanisms of GCR are essential. In this study, we addressed the hypothesis that TNFα, a strong pro-inflammatory mediator in numerous inflammatory diseases, compromises the protective function of the glucocorticoid receptor (GR) against TNFα-induced lethal inflammation. Indeed, protection of mice by dexamethasone against TNFα lethality was completely abolished when it was administered after TNFα stimulation, indicating compromised GR function upon TNFα challenge. TNFα-induced GCR was further demonstrated by impaired GR-dependent gene expression in the liver. Furthermore, TNFα down-regulates the levels of both GR mRNA and protein. However, this down-regulation seems to occur independently of GC production, as TNFα also resulted in down-regulation of GR levels in adrenalectomized mice. These findings suggest that the decreased amount of GR determines the GR response and outcome of TNFα-induced shock, as supported by our studies with GR heterozygous mice. We propose that by inducing GCR, TNFα inhibits a major brake on inflammation and thereby amplifies the pro-inflammatory response. Our findings might prove helpful in understanding GCR in inflammatory diseases in which TNFα is intimately involved. PMID:21646349

  3. Transforming potential and matrix stiffness co-regulate confinement sensitivity of tumor cell migration

    PubMed Central

    Pathak, Amit

    2013-01-01

    It is now well established that tumor cell invasion through tissue is strongly regulated by the microstructural and mechanical properties of the extracellular matrix (ECM). However, it remains unclear how these physical microenvironmental inputs are jointly processed with oncogenic lesions to drive invasion. In this study, we address this open question by combining a microfabricated polyacrylamide channel (μPAC) platform that enables independent control of ECM stiffness and confinement with an isogenically-matched breast tumor progression series in which the oncogenes ErbB2 and 14-3-3ζ are overexpressed independently or in tandem. We find that increasing channel confinement and overexpressing ErbB2 both promote cell migration to a similar degree when other parameters are kept constant. In contrast, 14-3-3ζ overexpression slows migration speed, and does so in a fashion that dwarfs effects of ECM confinement and stiffness. We also find that ECM stiffness dramatically enhances cell motility when combined with ErbB2 overexpression, demonstrating that biophysical cues and cell-intrinsic parameters promote cell invasion in an integrative manner. Morphometric analysis of cells inside the μPAC platform reveals that the rapid cell migration induced by narrow channels and ErbB2 overexpression both are accompanied by increased cell polarization. Disruption of this polarization by pharmacological inhibition of Rac GTPase phenocopies 14-3-3ζ overexpression by reducing cell polarization and slowing migration. By systematically measuring migration speed as a function of matrix stiffness and confinement, we also quantify for the first time the sensitivity of migration speed to microchannel properties and transforming potential. These results demonstrate that oncogenic lesions and ECM biophysical properties can synergistically interact to drive invasive migration, and that both inputs may act through common molecular mechanisms to enhance migration speed. PMID:23832051

  4. Transforming potential and matrix stiffness co-regulate confinement sensitivity of tumor cell migration.

    PubMed

    Pathak, Amit; Kumar, Sanjay

    2013-08-01

    It is now well established that tumor cell invasion through tissue is strongly regulated by the microstructural and mechanical properties of the extracellular matrix (ECM). However, it remains unclear how these physical microenvironmental inputs are jointly processed with oncogenic lesions to drive invasion. In this study, we address this open question by combining a microfabricated polyacrylamide channel (μPAC) platform that enables independent control of ECM stiffness and confinement with an isogenically-matched breast tumor progression series in which the oncogenes ErbB2 and 14-3-3ζ are overexpressed independently or in tandem. We find that increasing channel confinement and overexpressing ErbB2 both promote cell migration to a similar degree when other parameters are kept constant. In contrast, 14-3-3ζ overexpression slows migration speed, and does so in a fashion that dwarfs effects of ECM confinement and stiffness. We also find that ECM stiffness dramatically enhances cell motility when combined with ErbB2 overexpression, demonstrating that biophysical cues and cell-intrinsic parameters promote cell invasion in an integrative manner. Morphometric analysis of cells inside the μPAC platform reveals that the rapid cell migration induced by narrow channels and ErbB2 overexpression are both accompanied by increased cell polarization. Disruption of this polarization occurs by pharmacological inhibition of Rac GTPase phenocopies 14-3-3ζ overexpression by reducing cell polarization and slowing migration. By systematically measuring migration speed as a function of matrix stiffness and confinement, we also quantify for the first time the sensitivity of migration speed to microchannel properties and transforming potential. These results demonstrate that oncogenic lesions and ECM biophysical properties can synergistically interact to drive invasive migration, and that both inputs may act through common molecular mechanisms to enhance migration speed.

  5. Inhibiting MDSC differentiation from bone marrow with phytochemical polyacetylenes drastically impairs tumor metastasis

    PubMed Central

    Wei, Wen-Chi; Lin, Sheng-Yen; Lan, Chun-Wen; Huang, Yu-Chen; Lin, Chih-Yu; Hsiao, Pei-Wen; Chen, Yet-Ran; Yang, Wen-Chin; Yang, Ning-Sun

    2016-01-01

    Myeloid-derived suppressor cells (MDSCs) are implicated in the promotion of tumor metastasis by protecting metastatic cancerous cells from immune surveillance and have thus been suggested as novel targets for cancer therapy. We demonstrate here that oral feeding with polyacetylenic glycosides (BP-E-F1) from the medicinal plant Bidens pilosa effectively suppresses tumor metastasis and inhibits tumor-induced accumulation of granulocytic (g) MDSCs, but does not result in body weight loss in a mouse mammary tumor-resection model. BP-E-F1 is further demonstrated to exert its anti-metastasis activity through inhibiting the differentiation and function of gMDSCs. Pharmacokinetic and mechanistic studies reveal that BP-E-F1 suppresses the differentiation of gMDSCs via the inhibition of a tumor-derived, G-CSF-induced signaling pathway in bone marrow cells of test mice. Taken together, our findings suggest that specific plant polyacetylenic glycosides that target gMDSC differentiation by communicating with bone marrow cells may hence be seriously considered for potential application as botanical drugs against metastatic cancers. PMID:27857157

  6. Combination of aspartic acid and glutamic acid inhibits tumor cell proliferation.

    PubMed

    Yamaguchi, Yoshie; Yamamoto, Katsunori; Sato, Yoshinori; Inoue, Shinjiro; Morinaga, Tetsuo; Hirano, Eiichi

    2016-01-01

    Placental extract contains several biologically active compounds, and pharmacological induction of placental extract has therapeutic effects, such as improving liver function in patients with hepatitis or cirrhosis. Here, we searched for novel molecules with an anti-tumor activity in placental extracts. Active molecules were separated by chromatographic analysis, and their antiproliferative activities were determined by a colorimetric assay. We identified aspartic acid and glutamic acid to possess the antiproliferative activity against human hepatoma cells. Furthermore, we showed that the combination of aspartic acid and glutamic acid exhibited enhanced antiproliferative activity, and inhibited Akt phosphorylation. We also examined in vivo tumor inhibition activity using the rabbit VX2 liver tumor model. The treatment mixture (emulsion of the amino acids with Lipiodol) administered by hepatic artery injection inhibited tumor cell growth of the rabbit VX2 liver. These results suggest that the combination of aspartic acid and glutamic acid may be useful for induction of tumor cell death, and has the potential for clinical use as a cancer therapeutic agent.

  7. Rottlerin exerts its anti-tumor activity through inhibition of Skp2 in breast cancer cells

    PubMed Central

    Hou, Yingying; Wang, Lixia; Ye, Xiantao; Zhao, Zhe; Zhou, Xiuxia; Li, Yali; Wang, Zhiwei

    2016-01-01

    Studies have investigated the tumor suppressive role of rottlerin in carcinogenesis. However, the molecular mechanisms of rottlerin-induced anti-tumor activity are largely unclear. Skp2 (S-phase kinase associated protein 2) has been validated to play an oncogenic role in a variety of human malignancies. Therefore, inactivation of Skp2 could be helpful for the treatment of human cancers. In the current study, we explore whether rottlerin could inhibit Skp2 expression, leading to inhibition of cell growth, migration and invasion in breast cancer cells. We found that rottlerin treatment inhibited cell growth, induced apoptosis and cell cycle arrest. We also revealed that rottlerin suppressed cell migration and invasion in breast cancer cells. Mechanically, we observed that rottlerin significantly down-regulated the expression of Skp2 in breast cancer cells. Importantly, overexpression of Skp2 abrogated rottlerin-mediated tumor suppressive activity, whereas down-regulation of Skp2 enhanced rottlerin-triggered anti-tumor function. Strikingly, we identified that rottlerin exhibited its anti-tumor potential partly through inactivation of Skp2 in breast cancer. Our findings indicate that rottlerin could be a potential safe agent for the treatment of breast cancer. PMID:27582552

  8. Inhibiting MDSC differentiation from bone marrow with phytochemical polyacetylenes drastically impairs tumor metastasis.

    PubMed

    Wei, Wen-Chi; Lin, Sheng-Yen; Lan, Chun-Wen; Huang, Yu-Chen; Lin, Chih-Yu; Hsiao, Pei-Wen; Chen, Yet-Ran; Yang, Wen-Chin; Yang, Ning-Sun

    2016-11-18

    Myeloid-derived suppressor cells (MDSCs) are implicated in the promotion of tumor metastasis by protecting metastatic cancerous cells from immune surveillance and have thus been suggested as novel targets for cancer therapy. We demonstrate here that oral feeding with polyacetylenic glycosides (BP-E-F1) from the medicinal plant Bidens pilosa effectively suppresses tumor metastasis and inhibits tumor-induced accumulation of granulocytic (g) MDSCs, but does not result in body weight loss in a mouse mammary tumor-resection model. BP-E-F1 is further demonstrated to exert its anti-metastasis activity through inhibiting the differentiation and function of gMDSCs. Pharmacokinetic and mechanistic studies reveal that BP-E-F1 suppresses the differentiation of gMDSCs via the inhibition of a tumor-derived, G-CSF-induced signaling pathway in bone marrow cells of test mice. Taken together, our findings suggest that specific plant polyacetylenic glycosides that target gMDSC differentiation by communicating with bone marrow cells may hence be seriously considered for potential application as botanical drugs against metastatic cancers.

  9. Inhibition of lipid peroxidation, cyclooxygenase enzyme and human tumor cell proliferation by compounds in herbal water.

    PubMed

    Liu, Yunbao; Mulabagal, Vanisree; Bowen-Forbes, Camille S; Aviayan, Rejanish; Nair, Muraleedharan G

    2009-09-01

    A powdered mixture of dried herbs, "Panamrutham", is sold in India for the preparation of "herbal drinking water". The hot water extract of this herbal mixture gave lipid peroxidation (LPO), cyclo-oxygenase (COX-1 and -2) enzyme and human tumor cell proliferation inhibitory activities between 25 and 250 microg/mL. The bioassay-guided purification of the water extract afforded a novel compound (1), along with phenolics (2, 4, 6, and 7) and sesquiterpenoids (3 and 5). The isolates were evaluated for LPO, COX-1 and -2 enzyme and human tumor cell proliferation inhibitory activities. At 25 microg/mL, compounds 1-7 inhibited LPO by 22-73% and COX-1 and -2 enzymes by 3-14% and 14-74%, respectively. Compounds 5 and 6 at 25 microg/mL showed growth inhibition of colon, gastric, lung, breast and central nervous system human tumor cell lines by 60 and 67, 43 and 60, 24 and 64, 34 and 65, 6 and 27%, respectively. Compounds 2, 4 and 7 displayed weak or moderate growth inhibition of colon, gastric and breast human tumor cell lines. This is the first report on the LPO inhibitory activities of compounds 1 and 3-7 and the COX and tumor cell proliferation inhibitory activities of compounds 1, 3-5 and 7.

  10. Identification of breast cancer cell subtypes sensitive to ATG4B inhibition

    PubMed Central

    Bortnik, Svetlana; Choutka, Courtney; Horlings, Hugo M.; Leung, Samuel; Baker, Jennifer H.; Lebovitz, Chandra; Dragowska, Wieslawa H.; Go, Nancy E.; Bally, Marcel B.; Minchinton, Andrew I.; Gelmon, Karen A.; Gorski, Sharon M.

    2016-01-01

    Autophagy, a lysosome-mediated degradation and recycling process, functions in advanced malignancies to promote cancer cell survival and contribute to cancer progression and drug resistance. While various autophagy inhibition strategies are under investigation for cancer treatment, corresponding patient selection criteria for these autophagy inhibitors need to be developed. Due to its central roles in the autophagy process, the cysteine protease ATG4B is one of the autophagy proteins being pursued as a potential therapeutic target. In this study, we investigated the expression of ATG4B in breast cancer, a heterogeneous disease comprised of several molecular subtypes. We examined a panel of breast cancer cell lines, xenograft tumors, and breast cancer patient specimens for the protein expression of ATG4B, and found a positive association between HER2 and ATG4B protein expression. We showed that HER2-positive cells, but not HER2-negative breast cancer cells, require ATG4B to survive under stress. In HER2-positive cells, cytoprotective autophagy was dependent on ATG4B under both starvation and HER2 inhibition conditions. Combined knockdown of ATG4B and HER2 by siRNA resulted in a significant decrease in cell viability, and the combination of ATG4B knockdown with trastuzumab resulted in a greater reduction in cell viability compared to trastuzumab treatment alone, in both trastuzumab-sensitive and -resistant HER2 overexpressing breast cancer cells. Together these results demonstrate a novel association of ATG4B positive expression with HER2 positive breast cancers and indicate that this subtype is suitable for emerging ATG4B inhibition strategies. PMID:27556700

  11. Ras inhibition boosts galectin-7 at the expense of galectin-1 to sensitize cells to apoptosis

    PubMed Central

    Barkan, Batya; D. Cox, Adrienne; Kloog, Yoel

    2013-01-01

    Galectins are a family of β-galactoside-binding lectins that exert diverse extracellular and intracellular effects. Galectin-7 and galectin-1 show opposing effects on proliferation and survival in different cell types. Galectin-7 is a p53-induced gene and an enhancer of apoptosis, whereas galectin-1 induces tumorigenicity and resistance to apoptosis in several types of cancers. We show here that in cells derived from neurofibromin-deficient (Nf1−/−) malignant peripheral nerve sheath tumors (MPNSTs), Ras inhibition by S-trans,trans-farnesylthiosalicylic-acid (FTS; Salirasib) shifts the pattern of galectin expression. Whereas FTS decreased levels of both active Ras and galectin-1 expression, it dramatically increased both the mRNA and protein expression levels of galectin-7. Galectin-7 accumulation was mediated through JNK inhibition presumably resulting from the observed induction of p53, and was negatively regulated by the AP-1 inhibitor JDP2. Expression of galectin-7 by itself decreased Ras activation in ST88-14 cells and rendered them sensitive to apoptosis. This observed shift in galectin expression pattern together with the accompanying shift from cell proliferation to apoptosis represents a novel pattern of Ras inhibition by FTS. This seems likely to be an important phenomenon in view of the fact that both enhanced cell proliferation and defects of apoptosis constitute major hallmarks of human cancers and play a central role in the resistance of MPNSTs to anti-cancer treatments. These findings suggest that FTS, alone or in combination with chemotherapy agents, may be worth developing as a possible treatment for MPNSTs. PMID:23530091

  12. Ras inhibition boosts galectin-7 at the expense of galectin-1 to sensitize cells to apoptosis.

    PubMed

    Barkan, Batya; Cox, Adrienne D; Kloog, Yoel

    2013-02-01

    Galectins are a family of β-galactoside-binding lectins that exert diverse extracellular and intracellular effects. Galectin-7 and galectin-1 show opposing effects on proliferation and survival in different cell types. Galectin-7 is a p53-induced gene and an enhancer of apoptosis, whereas galectin-1 induces tumorigenicity and resistance to apoptosis in several types of cancers. We show here that in cells derived from neurofibromin-deficient (Nf1(-/-)) malignant peripheral nerve sheath tumors (MPNSTs), Ras inhibition by S-trans,trans-farnesylthiosalicylic-acid (FTS; Salirasib) shifts the pattern of galectin expression. Whereas FTS decreased levels of both active Ras and galectin-1 expression, it dramatically increased both the mRNA and protein expression levels of galectin-7. Galectin-7 accumulation was mediated through JNK inhibition presumably resulting from the observed induction of p53, and was negatively regulated by the AP-1 inhibitor JDP2. Expression of galectin-7 by itself decreased Ras activation in ST88-14 cells and rendered them sensitive to apoptosis. This observed shift in galectin expression pattern together with the accompanying shift from cell proliferation to apoptosis represents a novel pattern of Ras inhibition by FTS. This seems likely to be an important phenomenon in view of the fact that both enhanced cell proliferation and defects of apoptosis constitute major hallmarks of human cancers and play a central role in the resistance of MPNSTs to anti-cancer treatments. These findings suggest that FTS, alone or in combination with chemotherapy agents, may be worth developing as a possible treatment for MPNSTs.

  13. Cell-permeable iron inhibits vascular endothelial growth factor receptor-2 signaling and tumor angiogenesis

    PubMed Central

    Kir, Devika; Saluja, Manju; Modi, Shrey; Venkatachalam, Annapoorna; Schnettler, Erica; Roy, Sabita; Ramakrishnan, Sundaram

    2016-01-01

    Angiogenesis is important for tumor growth and metastasis. Hypoxia in tumors drives this angiogenic response by stabilizing Hypoxia Inducible Factors (HIF) and target genes like Vascular Endothelial Growth Factor (VEGF). HIF stability is regulated by Prolylhydroxylases (PHD)-mediated modification. Iron is an important cofactor in regulating the enzymatic activity of PHDs. Reducing intracellular iron, for instance, mimics hypoxia and induces a pro-angiogenic response. It is hypothesized that increasing the intracellular iron levels will have an opposite, anti-angiogenic effect. We tested this hypothesis by perturbing iron homeostasis in endothelial cells using a unique form of iron, Ferric Ammonium Citrate (FAC). FAC is a cell-permeable form of iron, which can passively enter into cells bypassing the transferrin receptor mediated uptake of transferrin-bound iron. Our studies show that FAC does not decrease the levels of HIF-1α and HIF-2α in endothelial cells but inhibits the autocrine stimulation of VEGF-Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) system by blocking receptor tyrosine kinase phosphorylation. FAC inhibits VEGF-induced endothelial cell proliferation, migration, tube formation and sprouting. Finally, systemic administration of FAC inhibits VEGF and tumor cell-induced angiogenesis in vivo. In conclusion, our studies show that cell-permeable iron attenuates VEGFR-2 mediated signaling and inhibits tumor angiogenesis. PMID:27589831

  14. Orally Administered Mucolytic Drug l-Carbocisteine Inhibits Angiogenesis and Tumor Growth in Mice.

    PubMed

    Shinya, Tomohiro; Yokota, Tsubasa; Nakayama, Shiori; Oki, Sayuri; Mutoh, Junpei; Takahashi, Satoru; Sato, Keizo

    2015-09-01

    Angiogenesis, the formation of new blood vessels from pre-existing vessels, is essential for the growth and metastasis of tumors. In this study, we found that l-carbocisteine, a widely used expectorant, potently inhibits angiogenesis in vitro and in vivo. An in vivo Matrigel plug assay revealed that l-carbocisteine (2.5 mg/kg i.p. twice daily) significantly inhibited vascular endothelial growth factor (VEGF)-induced angiogenesis. l-Carbocisteine also suppressed VEGF-stimulated proliferation, migration, and formation of capillary-like structures of human umbilical vein endothelial cells (HUVECs). We examined the signaling pathways affected in VEGF-stimulated HUVECs, and found that l-carbocisteine significantly inhibited VEGF-induced phosphorylation of phospholipase C (PLC) γ, protein kinase C (PKC) μ, and extracellular signal-related kinases (ERK) 1/2, which have been shown to be essential for angiogenesis. However, these inhibitory effects of l-carbocisteine were not observed in the HeLa human cervical cancer cell line. An in vivo study of Colon-26 tumor-bearing mice found that tumor volumes were significantly smaller in mice treated with l-carbocisteine (150 mg/kg administered orally twice daily) in comparison with vehicle-treated mice. However, l-carbocisteine had no direct effect on Colon-26 cell proliferation or ERK activation. Collectively, our results suggest that l-carbocisteine inhibits tumor angiogenesis by suppressing PLCγ/PKC/ERK signaling.

  15. Cell-permeable iron inhibits vascular endothelial growth factor receptor-2 signaling and tumor angiogenesis.

    PubMed

    Kir, Devika; Saluja, Manju; Modi, Shrey; Venkatachalam, Annapoorna; Schnettler, Erica; Roy, Sabita; Ramakrishnan, Sundaram

    2016-10-04

    Angiogenesis is important for tumor growth and metastasis. Hypoxia in tumors drives this angiogenic response by stabilizing Hypoxia Inducible Factors (HIF) and target genes like Vascular Endothelial Growth Factor (VEGF). HIF stability is regulated by Prolylhydroxylases (PHD)-mediated modification. Iron is an important cofactor in regulating the enzymatic activity of PHDs. Reducing intracellular iron, for instance, mimics hypoxia and induces a pro-angiogenic response. It is hypothesized that increasing the intracellular iron levels will have an opposite, anti-angiogenic effect. We tested this hypothesis by perturbing iron homeostasis in endothelial cells using a unique form of iron, Ferric Ammonium Citrate (FAC). FAC is a cell-permeable form of iron, which can passively enter into cells bypassing the transferrin receptor mediated uptake of transferrin-bound iron. Our studies show that FAC does not decrease the levels of HIF-1α and HIF-2α in endothelial cells but inhibits the autocrine stimulation of VEGF-Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) system by blocking receptor tyrosine kinase phosphorylation. FAC inhibits VEGF-induced endothelial cell proliferation, migration, tube formation and sprouting. Finally, systemic administration of FAC inhibits VEGF and tumor cell-induced angiogenesis in vivo. In conclusion, our studies show that cell-permeable iron attenuates VEGFR-2 mediated signaling and inhibits tumor angiogenesis.

  16. Different sensitivity of cells from tumor-bearing organisms to continuous-wave and pulsed laser radiation (lambda = 632.8 nm) evaluated by chemiluminescence test

    NASA Astrophysics Data System (ADS)

    Karu, Tiina I.; Ryabykh, T. P.; Antonov, Sergei N.; Letokhov, Vladilen S.

    1996-11-01

    Chemiluminescence test results were used to evaluate the sensitivity of human blood and murine splenocytes to continuous-wave (CW) and pulsed He-Ne laser light. It is demonstrated that CW radiation has in our experimental conditions practically no effect on the luminol-amplified chemiluminescence of four models under study. The pulsed radiation had a week inhibiting effect on the samples from healthy organisms but inhibited markedly the chemiluminescence of samples from tumor-bearing organisms. The effect depended on duration of dark period between pulses. A transient local heating mechanism is proposed to explain the inhibition of activity of NADPH-oxidase.

  17. Inhibition during response preparation is sensitive to response complexity

    PubMed Central

    Saks, Dylan; Hoang, Timothy; Ivry, Richard B.

    2015-01-01

    Motor system excitability is transiently suppressed during the preparation of movement. This preparatory inhibition is hypothesized to facilitate response selection and initiation. Given that demands on selection and initiation processes increase with movement complexity, we hypothesized that complexity would influence preparatory inhibition. To test this hypothesis, we probed corticospinal excitability during a delayed-response task in which participants were cued to prepare right- or left-hand movements of varying complexity. Single-pulse transcranial magnetic stimulation was applied over right primary motor cortex to elicit motor evoked potentials (MEPs) from the first dorsal interosseous (FDI) of the left hand. MEP suppression was greater during the preparation of responses involving coordination of the FDI and adductor digiti minimi relative to easier responses involving only the FDI, independent of which hand was cued to respond. In contrast, this increased inhibition was absent when the complex responses required sequential movements of the two muscles. Moreover, complexity did not influence the level of inhibition when the response hand was fixed for the trial block, regardless of whether the complex responses were performed simultaneously or sequentially. These results suggest that preparatory inhibition contributes to response selection, possibly by suppressing extraneous movements when responses involve the simultaneous coordination of multiple effectors. PMID:25717168

  18. ICAM-1 suppresses tumor metastasis by inhibiting macrophage M2 polarization through blockade of efferocytosis

    PubMed Central

    Yang, M; Liu, J; Piao, C; Shao, J; Du, J

    2015-01-01

    Efficient clearance of apoptotic cells (efferocytosis) can profoundly influence tumor-specific immunity. Tumor-associated macrophages are M2-polarized macrophages that promote key processes in tumor progression. Efferocytosis stimulates M2 macrophage polarization and contributes to cancer metastasis, but the signaling mechanism underlying this process is unclear. Intercellular cell adhesion molecule-1 (ICAM-1) is a transmembrane glycoprotein member of the immunoglobulin superfamily, which has been implicated in mediating cell–cell interaction and outside-in cell signaling during the immune response. We report that ICAM-1 expression is inversely associated with macrophage infiltration and the metastasis index in human colon tumors by combining Oncomine database analysis and immunohistochemistry for ICAM-1. Using a colon cancer liver metastasis model in ICAM-1-deficient (ICAM-1−/−) mice and their wild-type littermates, we found that loss of ICAM-1 accelerated liver metastasis of colon carcinoma cells. Moreover, ICAM-1 deficiency increased M2 macrophage polarization during tumor progression. We further demonstrated that ICAM-1 deficiency in macrophages led to promotion of efferocytosis of apoptotic tumor cells through activation of the phosphatidylinositol 3 kinase/Akt signaling pathway. More importantly, coculture of ICAM-1−/− macrophages with apoptotic cancer cells resulted in an increase of M2-like macrophages, which was blocked by an efferocytosis inhibitor. Our findings demonstrate a novel role for ICAM-1 in suppressing M2 macrophage polarization via downregulation of efferocytosis in the tumor microenvironment, thereby inhibiting metastatic tumor progression. PMID:26068788

  19. Biomarker- versus drug-driven tumor growth inhibition models: an equivalence analysis.

    PubMed

    Sardu, Maria Luisa; Poggesi, Italo; De Nicolao, Giuseppe

    2015-12-01

    The mathematical modeling of tumor xenograft experiments following the dosing of antitumor drugs has received much attention in the last decade. Biomarker data can further provide useful insights on the pathological processes and be used for translational purposes in the early clinical development. Therefore, it is of particular interest the development of integrated pharmacokinetic-pharmacodynamic (PK-PD) models encompassing drug, biomarker and tumor-size data. This paper investigates the reciprocal consistency of three types of models: drug-to-tumor, such as established drug-driven tumor growth inhibition (TGI) models, drug-to-biomarker, e.g. indirect response models, and biomarker-to-tumor, e.g. the more recent biomarker-driven TGI models. In particular, this paper derives a mathematical relationship that guarantees the steady-state equivalence of the cascade of drug-to-biomarker and biomarker-to-tumor models with a drug-to-tumor TGI model. Using the Simeoni TGI model as a reference, conditions for steady-state equivalence are worked out and used to derive a new biomarker-driven model. Simulated and real data are used to show that in realistic cases the steady-state equivalence extends also to transient responses. The possibility of predicting the drug-to-tumor potency of a new candidate drug based only on biomarker response is discussed.

  20. Polyoxazoline multivalently conjugated with indocyanine green for sensitive in vivo photoacoustic imaging of tumors

    PubMed Central

    Kanazaki, Kengo; Sano, Kohei; Makino, Akira; Homma, Tsutomu; Ono, Masahiro; Saji, Hideo

    2016-01-01

    Photoacoustic imaging, which enables high-resolution imaging in deep tissues, has lately attracted considerable attention. For tumor imaging, photoacoustic probes have been proposed to enhance the photoacoustic effect to improve detection sensitivity. Here, we evaluated the feasibility of using a biocompatible hydrophilic polymer, polyoxazoline, conjugated with indocyanine green (ICG) as a tumor-targeted photoacoustic probe via enhanced permeability and retention effect. ICG molecules were multivalently conjugated to partially hydrolyzed polyoxazoline, thereby serving as highly sensitive photoacoustic probes. Interestingly, loading multiple ICG molecules to polyoxazoline significantly enhanced photoacoustic signal intensity under the same ICG concentration. In vivo biodistribution studies using tumor bearing mice demonstrated that 5% hydrolyzed polyoxazoline (50 kDa) conjugated with ICG (ICG/polyoxazoline = 7.8), P14-ICG7.8, showed relatively high tumor accumulation (9.4%ID/g), resulting in delivery of the highest dose of ICG among the probes tested. P14-ICG7.8 enabled clear visualization of the tumor regions by photoacoustic imaging 24 h after administration; the photoacoustic signal increased in proportion with the injected dose. In addition, the signal intensity in blood vessels in the photoacoustic images did not show much change, which was attributed to the high tumor-to-blood ratios of P14-ICG7.8. These results suggest that polyoxazoline-ICG would serve as a robust probe for sensitive photoacoustic tumor imaging. PMID:27667374

  1. Polyoxazoline multivalently conjugated with indocyanine green for sensitive in vivo photoacoustic imaging of tumors.

    PubMed

    Kanazaki, Kengo; Sano, Kohei; Makino, Akira; Homma, Tsutomu; Ono, Masahiro; Saji, Hideo

    2016-09-26

    Photoacoustic imaging, which enables high-resolution imaging in deep tissues, has lately attracted considerable attention. For tumor imaging, photoacoustic probes have been proposed to enhance the photoacoustic effect to improve detection sensitivity. Here, we evaluated the feasibility of using a biocompatible hydrophilic polymer, polyoxazoline, conjugated with indocyanine green (ICG) as a tumor-targeted photoacoustic probe via enhanced permeability and retention effect. ICG molecules were multivalently conjugated to partially hydrolyzed polyoxazoline, thereby serving as highly sensitive photoacoustic probes. Interestingly, loading multiple ICG molecules to polyoxazoline significantly enhanced photoacoustic signal intensity under the same ICG concentration. In vivo biodistribution studies using tumor bearing mice demonstrated that 5% hydrolyzed polyoxazoline (50 kDa) conjugated with ICG (ICG/polyoxazoline = 7.8), P14-ICG7.8, showed relatively high tumor accumulation (9.4%ID/g), resulting in delivery of the highest dose of ICG among the probes tested. P14-ICG7.8 enabled clear visualization of the tumor regions by photoacoustic imaging 24 h after administration; the photoacoustic signal increased in proportion with the injected dose. In addition, the signal intensity in blood vessels in the photoacoustic images did not show much change, which was attributed to the high tumor-to-blood ratios of P14-ICG7.8. These results suggest that polyoxazoline-ICG would serve as a robust probe for sensitive photoacoustic tumor imaging.

  2. RhoE is required for contact inhibition and negatively regulates tumor initiation and progression.

    PubMed

    Hernández-Sánchez, Marta; Poch, Enric; Guasch, Rosa M; Ortega, Joaquín; López-Almela, Inmaculada; Palmero, Ignacio; Pérez-Roger, Ignacio

    2015-07-10

    RhoE is a small GTPase involved in the regulation of actin cytoskeleton dynamics, cell cycle and apoptosis. The role of RhoE in cancer is currently controversial, with reports of both oncogenic and tumor-suppressive functions for RhoE. Using RhoE-deficient mice, we show here that the absence of RhoE blunts contact-inhibition of growth by inhibiting p27Kip1 nuclear translocation and cooperates in oncogenic transformation of mouse primary fibroblasts. Heterozygous RhoE+/gt mice are more susceptible to chemically induced skin tumors and RhoE knock-down results in increased metastatic potential of cancer cells. These results indicate that RhoE plays a role in suppressing tumor initiation and progression.

  3. RhoE is required for contact inhibition and negatively regulates tumor initiation and progression

    PubMed Central

    Hernández-Sánchez, Marta; Poch, Enric; Guasch, Rosa M.; Ortega, Joaquín; López-Almela, Inmaculada; Palmero, Ignacio; Pérez-Roger, Ignacio

    2015-01-01

    RhoE is a small GTPase involved in the regulation of actin cytoskeleton dynamics, cell cycle and apoptosis. The role of RhoE in cancer is currently controversial, with reports of both oncogenic and tumor-suppressive functions for RhoE. Using RhoE-deficient mice, we show here that the absence of RhoE blunts contact-inhibition of growth by inhibiting p27Kip1 nuclear translocation and cooperates in oncogenic transformation of mouse primary fibroblasts. Heterozygous RhoE+/gt mice are more susceptible to chemically induced skin tumors and RhoE knock-down results in increased metastatic potential of cancer cells. These results indicate that RhoE plays a role in suppressing tumor initiation and progression. PMID:26036260

  4. LZAP, a putative tumor suppressor, selectively inhibits NF-kappaB.

    PubMed

    Wang, Jialiang; An, Hanbing; Mayo, Marty W; Baldwin, Albert S; Yarbrough, Wendell G

    2007-09-01

    LZAP has been reported to inhibit cellular proliferation and clonogenic growth. Here, we report that decreased LZAP expression promoted cellular transformation, xenograft tumor growth, and xenograft tumor vascularity. Loss of LZAP also increased cellular invasion, and MMP-9 expression dependent on NF-kappaB. LZAP directly bound to RelA, impaired serine 536 phosphorylation of RelA, increased HDAC association with RelA, inhibited basal and stimulated NF-kappaB transcriptional activity, and was found at the promoter of selective NF-kappaB-responsive genes. LZAP protein levels were markedly decreased in 32% of primary HNSCCs (n = 28) and decreased LZAP levels in primary HNSCC correlated with increased expression of the NF-kappaB-regulated genes IL-8 and IkappaBalpha. In aggregate, these data support a role of LZAP in NF-kappaB regulation and tumor suppression.

  5. Xanthatin, a novel potent inhibitor of VEGFR2 signaling, inhibits angiogenesis and tumor growth in breast cancer cells.

    PubMed

    Yu, Yao; Yu, Jing; Pei, Chong Gang; Li, Yun Yan; Tu, Ping; Gao, Gui Ping; Shao, Yi

    2015-01-01

    Anti-angiogenesis targeting vascular endothelial growth factor receptor 2 (VEGFR2) has emerged as an important tool for cancer treatment. In this study, we described a novel VEGFR2 inhibitor, xanthatin, which inhibits tumor angiogenesis and growth. The biochemical profiles of xanthatin were investigated using kinase assay, migration assay, tube formation, Matrigel plug assay, western blot, immunofluorescence and human tumor xenograft model. Xanthatin significantly inhibited growth, migration and tube formation of human umbilical vascular endothelial cell as well as inhibited vascular endothelial growth factor (VEGF)-stimulated angiogenesis. In addition, it inhibited VEGF-induced phosphorylation of VEGFR2 and its downstream signaling regulator. Moreover, xanthatin directly inhibit proliferation of breast cancer cells MDA-MB-231. Oral administration of xanthatin could markedly inhibit human tumor xenograft growth and decreased microvessel densities (MVD) in tumor sections. Taken together, these preclinical evaluations suggest that xanthatin inhibits angiogenesis and may be a promising anticancer drug candidate.

  6. Antithrombin controls tumor migration, invasion and angiogenesis by inhibition of enteropeptidase

    PubMed Central

    Luengo-Gil, Ginés; Calvo, María Inmaculada; Martín-Villar, Ester; Águila, Sonia; Bohdan, Nataliya; Antón, Ana I.; Espín, Salvador; Ayala de la Peña, Francisco; Vicente, Vicente; Corral, Javier; Quintanilla, Miguel; Martínez-Martínez, Irene

    2016-01-01

    Antithrombin is a key inhibitor of the coagulation cascade, but it may also function as an anti-inflammatory, anti-angiogenic, anti-viral and anti-apoptotic protein. Here, we report a novel function of antithrombin as a modulator of tumor cell migration and invasion. Antithrombin inhibited enteropeptidase on the membrane surface of HT-29, A549 and U-87 MG cells. The inhibitory process required the activation of antithrombin by heparin, and the reactive center loop and the heparin binding domain were essential. Surprisingly, antithrombin non-covalently inhibited enteropeptidase, revealing a novel mechanism of inhibition for this serpin. Moreover, as a consequence of this inhibition, antithrombin was cleaved, resulting in a molecule with anti-angiogenic properties that reduced vessel-like formation of endothelial cells. The addition of antithrombin and heparin to U-87 MG and A549 cells reduced motility in wound healing assays, inhibited the invasion in transwell assays and the degradation of a gelatin matrix mediated by invadopodia. These processes were controlled by enteropeptidase, as demonstrated by RNA interference experiments. Carcinoma cell xenografts in nude mice showed in vivo co-localization of enteropeptidase and antithrombin. Finally, treatment with heparin reduced experimental metastasis induced by HT29 cells in vivo. In conclusion, the inhibition of enteropeptidase by antithrombin may have a double anti-tumor effect through inhibiting a protease involved in metastasis and generating an anti-angiogenic molecule. PMID:27270881

  7. Antithrombin controls tumor migration, invasion and angiogenesis by inhibition of enteropeptidase.

    PubMed

    Luengo-Gil, Ginés; Calvo, María Inmaculada; Martín-Villar, Ester; Águila, Sonia; Bohdan, Nataliya; Antón, Ana I; Espín, Salvador; Ayala de la Peña, Francisco; Vicente, Vicente; Corral, Javier; Quintanilla, Miguel; Martínez-Martínez, Irene

    2016-06-08

    Antithrombin is a key inhibitor of the coagulation cascade, but it may also function as an anti-inflammatory, anti-angiogenic, anti-viral and anti-apoptotic protein. Here, we report a novel function of antithrombin as a modulator of tumor cell migration and invasion. Antithrombin inhibited enteropeptidase on the membrane surface of HT-29, A549 and U-87 MG cells. The inhibitory process required the activation of antithrombin by heparin, and the reactive center loop and the heparin binding domain were essential. Surprisingly, antithrombin non-covalently inhibited enteropeptidase, revealing a novel mechanism of inhibition for this serpin. Moreover, as a consequence of this inhibition, antithrombin was cleaved, resulting in a molecule with anti-angiogenic properties that reduced vessel-like formation of endothelial cells. The addition of antithrombin and heparin to U-87 MG and A549 cells reduced motility in wound healing assays, inhibited the invasion in transwell assays and the degradation of a gelatin matrix mediated by invadopodia. These processes were controlled by enteropeptidase, as demonstrated by RNA interference experiments. Carcinoma cell xenografts in nude mice showed in vivo co-localization of enteropeptidase and antithrombin. Finally, treatment with heparin reduced experimental metastasis induced by HT29 cells in vivo. In conclusion, the inhibition of enteropeptidase by antithrombin may have a double anti-tumor effect through inhibiting a protease involved in metastasis and generating an anti-angiogenic molecule.

  8. Chicken HSP70 DNA vaccine inhibits tumor growth in a canine cancer model.

    PubMed

    Yu, Wen-Ying; Chuang, Tien-Fu; Guichard, Cécile; El-Garch, Hanane; Tierny, Dominique; Laio, Albert Taiching; Lin, Ching-Si; Chiou, Kuo-Hao; Tsai, Cheng-Long; Liu, Chen-Hsuan; Li, Wen-Chiuan; Fischer, Laurent; Chu, Rea-Min

    2011-04-18

    Immunization with xenogeneic DNA is a promising cancer treatment to overcome tolerance to self-antigens. Heat shock protein 70 (HSP70) is over-expressed in various kinds of tumors and is believed to be involved in tumor progression. This study tested a xenogeneic chicken HSP70 (chHSP70) DNA vaccine in an experimental canine transmissible venereal tumor (CTVT) model. Three vaccination strategies were compared: the first (PE) was designed to evaluate the prophylactic efficacy of chHSP70 DNA vaccination by delivering the vaccine before tumor inoculation in a prime boost setting, the second (T) was designed to evaluate the therapeutic efficacy of the same prime boost vaccine by vaccinating the dogs after tumor inoculation; the third (PT) was similar to the first strategy (PE), with the exception that the electroporation booster injection was replaced with a transdermal needle-free injection. Tumor growth was notably inhibited only in the PE dogs, in which the vaccination program triggered tumor regression significantly sooner than in control dogs (NT). The CD4(+) subpopulation of tumor-infiltrating lymphocytes and canine HSP70 (caHSP70)-specific IFN-γ-secreting lymphocytes were significantly increased during tumor regression in the PE dogs as compared to control dogs, demonstrating that specific tolerance to caHSP70 has been overcome. In contrast, no benefit of the therapeutic strategy (T) could be noticed and the (PT) strategy only led to partial control of tumor growth. In summary, antitumor prophylactic activity was demonstrated using the chHSP70 DNA vaccine including a boost via electroporation. Our data stressed the importance of DNA electroporation as a booster to get the full benefit of DNA vaccination but also of cancer immunotherapy initiation as early as possible. Xenogeneic chHSP70 DNA vaccination including an electroporation boost is a potential vaccine to HSP70-expressing tumors, although further research is still required to better understand true

  9. Therapeutic inhibition of Jak activity inhibits progression of gastrointestinal tumors in mice.

    PubMed

    Stuart, Emma; Buchert, Michael; Putoczki, Tracy; Thiem, Stefan; Farid, Ryan; Elzer, Joachim; Huszar, Dennis; Waring, Paul M; Phesse, Toby J; Ernst, Matthias

    2014-02-01

    Aberrant activation of the latent transcription factor STAT3 and its downstream targets is a common feature of epithelial-derived human cancers, including those of the gastrointestinal tract. Mouse models of gastrointestinal malignancy implicate Stat3 as a key mediator of inflammatory-driven tumorigenesis, in which its cytokine/gp130/Janus kinase (Jak)-dependent activation provides a functional link through which the microenvironment sustains tumor promotion. Although therapeutic targeting of STAT3 is highly desirable, such molecules are not available for immediate clinical assessment. Here, we investigated whether the small-molecule Jak1/2 inhibitor AZD1480 confers therapeutic benefits in two mouse models of inflammation-associated gastrointestinal cancer, which are strictly dependent of excessive Stat3 activation. We confirm genetically that Cre-mediated, tumor cell-specific reduction of Stat3 expression arrests the growth of intestinal-type gastric tumors in gp130(F/F) mice. We find that systemic administration of AZD1480 readily replicates this effect, which is associated with reduced Stat3 activation and correlates with diminished tumor cell proliferation and increased apoptosis. Likewise, AZD1480 therapy also conferred a cytostatic effect on established tumors in a colitis-associated colon cancer model in wild-type mice. As predicted from our genetic observations in gp130(F/F) mice, the therapeutic effect of AZD1480 remains fully reversible upon cessation of compound administration. Collectively, our results provide the first evidence that pharmacologic targeting of excessively activated wild-type Jak kinases affords therapeutic suppression of inflammation-associated gastrointestinal cancers progression in vivo.

  10. Biodegradable polymeric micelles encapsulated JK184 suppress tumor growth through inhibiting Hedgehog signaling pathway

    NASA Astrophysics Data System (ADS)

    Zhang, Nannan; Liu, Shichang; Wang, Ning; Deng, Senyi; Song, Linjiang; Wu, Qinjie; Liu, Lei; Su, Weijun; Wei, Yuquan; Xie, Yongmei; Gong, Changyang

    2015-01-01

    JK184 can specially inhibit Gli in the Hedgehog (Hh) pathway, which showed great promise for cancer therapeutics. For developing aqueous formulation and improving anti-tumor activity of JK184, we prepared JK184 encapsulated MPEG-PCL micelles by the solid dispersion method without using surfactants or toxic organic solvents. The cytotoxicity and cellular uptake of JK184 micelles were both increased compared with the free drug. JK184 micelles induced more apoptosis and blocked proliferation of Panc-1 and BxPC-3 tumor cells. In addition, JK184 micelles exerted a sustained in vitro release behavior and had a stronger inhibitory effect on proliferation, migration and invasion of HUVECs than free JK184. Furthermore, JK184 micelles had stronger tumor growth inhibiting effects in subcutaneous Panc-1 and BxPC-3 tumor models. Histological analysis showed that JK184 micelles improved anti-tumor activity by inducing more apoptosis, decreasing microvessel density and reducing expression of CD31, Ki67, and VEGF in tumor tissues. JK184 micelles showed a stronger inhibition of Gli expression in Hh signaling, which played an important role in pancreatic carcinoma. Furthermore, circulation time of JK184 in blood was prolonged after entrapment in polymeric micelles. Our results suggested that JK184 micelles are a promising drug candidate for treating pancreatic tumors with a highly inhibitory effect on Hh activity.JK184 can specially inhibit Gli in the Hedgehog (Hh) pathway, which showed great promise for cancer therapeutics. For developing aqueous formulation and improving anti-tumor activity of JK184, we prepared JK184 encapsulated MPEG-PCL micelles by the solid dispersion method without using surfactants or toxic organic solvents. The cytotoxicity and cellular uptake of JK184 micelles were both increased compared with the free drug. JK184 micelles induced more apoptosis and blocked proliferation of Panc-1 and BxPC-3 tumor cells. In addition, JK184 micelles exerted a sustained in

  11. Inhibition of oxidative phosphorylation in ascites tumor mitochondria and cells by intramitochondrial Ca2+.

    PubMed

    Villalobo, A; Lehninger, A L

    1980-03-25

    Accumulation of Ca2+ (+ phosphate) by respiring mitochondria from Ehrlich ascites or AS30-D hepatoma tumor cells inhibits subsequent phosphorylating respiration in response to ADP. The respiratory chain is still functional since a proton-conducting uncoupler produces a normal stimulation of electron transport. The inhibition of phosphorylating respiration is caused by intramitochondrial Ca2+ (+ phosphate). ATP + Mg2+ together, but not singly, prevents the inhibitory action of Ca2+. Neither AMP, GTP, GDP, nor any other nucleoside 5'-triphosphate or 5'-diphosphate could replace ATP in this effect. Phosphorylating respiration on NAD(NADP)-linked substrates was much more susceptible to the inhibitory effect of intramitochondrial Ca2+ than succinate-linked respiration. Significant inhibition of oxidative phosphorylation is given by the endogenous Ca2+ present in freshly isolated tumor mitochondria. The phosphorylating respiration of permeabilized Ehrlich ascites tumor cells is also inhibited by Ca2+ accumulated by the mitochondria in situ. Possible causes of the Ca2+-induced inhibition of oxidative phosphorylation are considered.

  12. Locally applied TCP inhibits tumor growth via possible activation of macrophages.

    PubMed

    Naito, Yukiko; Nagata, Tomoko; Tachibana, Shigehiro; Okimoto, Mari; Ohara, Naoki; Hakamatsuka, Yasuharu; Cheng, Jinyan

    2010-02-01

    The aim of this study was to investigate whether beta-tricalcium phosphate (TCP) inhibits cancer growth, because TCP, a widely used bone replacement material, is known to attract immune cells. Human colon cancer (WiDr) cells were subcutaneously injected on the backs of nude mice, and tumor growth was observed. Seven days after the injection, five animals were implanted with TCP at the tumor sites, five animals were treated by a direct application of 0.12 mg cisplatin at the sites, and four animals were not treated, as a control. Tumor size on the 43rd day of implantation was 1173 mm(3) in the TCP group and was smaller than that in the control, 1621 mm(3). This inhibition was comparable to that with cisplatin. Furthermore, tumor-growing rate in the TCP group was significantly lower than that in the control group. Histopathological examination of the tumors showed migration of macrophages only in the TCP group, with TCP particles remaining at the implantation loci. There were no between-group differences in neutrophil infiltration and angiogenesis. In another series of in vitro experiments, a concentration-dependent increase in luminol chemiluminescence was observed in isolated human peripheral neutrophils incubated with TCP, and the chemiluminescence due to phagocytosis of opsonized zymosan in the presence of TCP occurred with a lower level of TCP than when the chemiluminescence was due to TCP alone. These results suggest that subcutaneously implanted TCP inhibits tumor growth of implanted WiDr cells, and that the activation by TCP of macrophages plays a role in that inhibition. (c) 2009 Wiley Periodicals, Inc.

  13. Evaluation of combinations of drugs that inhibit Ehrlich tumor cell ribonucleotide reductase.

    PubMed

    Sato, A; Cory, J G

    1981-05-01

    The nature of the inhibition of Ehrlich tumor cell ribonucleotide reductase by combinations of agents directed at the non-heme iron-containing component and the effector-binding component was studied with the use of isobolograms. From these studies, it was determined that the combinations of pyrazoloimidazole (IMPY) and dialdehyde of inosine, IMPY and deoxyguanosine triphosphate (dGTP), IMPY and deoxyadenosine triphosphate (dATP), and IMPY and deoxythymidine triphosphate (dTTP) gave synergistic inhibition of cytidine diphosphate reductase. The combination of dATP and dGTP also gave synergistic inhibition. The combinations of hydroxyurea and IMPY, 4-methyl-5-aminoisoquinoline thiosemicarbazone (MAIQ) and IMPY, and dialdehyde of inosine and dialdehyde derivative of 5'-deoxyinosine gave antagonistic inhibition. Other combinations utilizing MAIQ and dATP, MAIQ and dGTP, MAIQ and dTTP, hydroxyurea and dGTP, and hydroxyurea and dTTP gave inhibition which was additive.

  14. Effect of low frequency magnetic fields on melanoma: tumor inhibition and immune modulation

    PubMed Central

    2013-01-01

    Background We previously found that the low frequency magnetic fields (LF-MF) inhibited gastric and lung cancer cell growth. We suppose that exposure to LF-MF may modulate immune function so as to inhibit tumor. We here investigated whether LF-MF can inhibit the proliferation and metastasis of melanoma and influence immune function. Methods The effect of MF on the proliferation, cell cycle and ultrastracture of B16-F10 in vitro was detected by cell counting Kit-8 assay, flow cytometry, and transmission electron microscopy. Lung metastasis mice were prepared by injection of 2 × 105 B16-F10 melanoma cells into the tail vein in C57BL/6 mice. The mice were then exposed to an LF-MF (0.4 T, 7.5 Hz) for 43 days. Survival rate, tumor markers and the innate and adaptive immune parameters were measured. Results The growth of B16-F10 cells was inhibited after exposure to the LF-MF. The inhibition was related to induction of cell cycle arrest and decomposition of chromatins. Moreover, the LF-MF prolonged the mouse survival rate and inhibited the proliferation of B16-F10 in melanoma metastasis mice model. Furthermore, the LF-MF modulated the immune response via regulation of immune cells and cytokine production. In addition, the number of Treg cells was decreased in mice with the LF-MF exposure, while the numbers of T cells as well as dendritic cells were significantly increased. Conclusion LF-MF inhibited the growth and metastasis of melanoma cancer cells and improved immune function of tumor-bearing mice. This suggests that the inhibition may be attributed to modulation of LF-MF on immune function and LF-MF may be a potential therapy for treatment of melanoma. PMID:24314291

  15. PTEN inhibits PREX2-catalyzed activation of RAC1 to restrain tumor cell invasion

    PubMed Central

    Mense, Sarah M.; Barrows, Douglas; Hodakoski, Cindy; Steinbach, Nicole; Schoenfeld, David; Su, William; Hopkins, Benjamin D.; Su, Tao; Fine, Barry; Hibshoosh, Hanina; Parsons, Ramon

    2016-01-01

    The tumor suppressor PTEN restrains cell migration and invasion by a mechanism that is independent of inhibition of the PI3K pathway and decreased activation of the kinase AKT. PREX2, a widely distributed GEF that activates the GTPase RAC1, binds to and inhibits PTEN. We used mouse embryonic fibroblasts and breast cancer cell lines to show that PTEN suppresses cell migration and invasion by blocking PREX2 activity. In addition to metabolizing the phosphoinositide PIP3, PTEN inhibited PREX2-induced invasion by a mechanism that required the tail domain of PTEN, but not its lipid phosphatase activity. Fluorescent nucleotide exchange assays revealed that PTEN inhibited the GEF activity of PREX2 toward RAC1. PREX2 is a frequently mutated GEF in cancer, and examination of human tumor data showed that PREX2 mutation was associated with high PTEN expression. Therefore, we tested whether cancer-derived somatic PREX2 mutants, which accelerate tumor formation of immortalized melanocytes, were inhibited by PTEN. The three stably expressed, somatic PREX2 cancer mutants that we tested were resistant to PTEN-mediated inhibition of invasion but retained the ability to inhibit the lipid phosphatase activity of PTEN. In vitro analysis showed that PTEN did not block the GEF activity of two PREX2 cancer mutants and had a reduced binding affinity for the third. Thus, PTEN antagonized migration and invasion by restraining PREX2 GEF activity, and PREX2 mutants are likely selected in cancer to escape PTEN-mediated inhibition of invasion. PMID:25829446

  16. Andrographolide inhibits melanoma tumor growth by inactivating the TLR4/NF-κB signaling pathway.

    PubMed

    Zhang, Qian-Qian; Zhou, Da-Lei; Ding, Yi; Liu, Hong-Ying; Lei, Yan; Fang, Hai-Yan; Gu, Qu-Liang; He, Xiao-Dong; Qi, Cui-Ling; Yang, Yi; Lan, Tian; Li, Jiang-Chao; Gong, Ping; Wu, Xiao-Yun; Yang, Xuesong; Li, Wei-Dong; Wang, Li-Jing

    2014-12-01

    The TLR4/NF-κB signaling pathway plays a critical role in tumor progression. Andrographolide (Andro) has been reported to have anticancer activity in multiple types of cancer. However, the pharmacological activities of Andro in melanoma are not completely understood. In this study, we defined the anticancer effects of Andro in melanoma and elucidated its potential mechanisms of action. Our experiments showed that Andro significantly inhibited melanoma tumor growth and metastasis by inducing cell cycle arrest and apoptosis. In addition, Andro significantly inhibited the TLR4/NF-κB signaling pathway. Furthermore, the inactivation of TLR4/NF-κB signaling inhibited the mRNA and protein expression of CXCR4 and Bcl-6, which are antitumor genes. This work provides evidence that the TLR4/NF-κB signaling pathway is a potential therapeutic target and may also be indispensable in the Andro-mediated anticancer effect in melanoma.

  17. A synthetic manassantin a derivative inhibits hypoxia-inducible factor 1 and tumor growth.

    PubMed

    Lang, Liwei; Liu, Xiaoyu; Li, Yan; Zhou, Qing; Xie, Ping; Yan, Chunhong; Chen, Xiaoguang

    2014-01-01

    The dineolignan manassantin A from Saururaceae was recently identified as a hypoxia-inducible factor 1 (HIF-1) inhibitor, but its in-vivo anti-tumor effect has not been explored. We synthesized a series of manassantin A derivatives, and found that replacing the central tetrahydrofuran moiety with a cyclopentane ring yielded a compound (LXY6006) with increased HIF-1-inhibitory activity yet decreased stereochemically complexity amenable to a simplified synthesis scheme. LXY6006 inhibited HIF-1α nuclear accumulation induced by hypoxia, and inhibited cancer cell growth as a consequence of G2/M arrest. Oral administration of LXY6006 significantly inhibited growth of breast, lung, and pancreatic tumors implanted in nude mice. These results indicate that LXY6006 represents a novel class of agents targeting a broad range of human cancers.

  18. A Synthetic Manassantin A Derivative Inhibits Hypoxia-Inducible Factor 1 and Tumor Growth

    PubMed Central

    Li, Yan; Zhou, Qing; Xie, Ping; Yan, Chunhong; Chen, Xiaoguang

    2014-01-01

    The dineolignan manassantin A from Saururaceae was recently identified as a hypoxia-inducible factor 1 (HIF-1) inhibitor, but its in-vivo anti-tumor effect has not been explored. We synthesized a series of manassantin A derivatives, and found that replacing the central tetrahydrofuran moiety with a cyclopentane ring yielded a compound (LXY6006) with increased HIF-1-inhibitory activity yet decreased stereochemically complexity amenable to a simplified synthesis scheme. LXY6006 inhibited HIF-1α nuclear accumulation induced by hypoxia, and inhibited cancer cell growth as a consequence of G2/M arrest. Oral administration of LXY6006 significantly inhibited growth of breast, lung, and pancreatic tumors implanted in nude mice. These results indicate that LXY6006 represents a novel class of agents targeting a broad range of human cancers. PMID:24925080

  19. MUC16 provides immune protection by inhibiting synapse formation between NK and ovarian tumor cells

    PubMed Central

    2010-01-01

    Background Cancer cells utilize a variety of mechanisms to evade immune detection and attack. Effective immune detection largely relies on the formation of an immune synapse which requires close contact between immune cells and their targets. Here, we show that MUC16, a heavily glycosylated 3-5 million Da mucin expressed on the surface of ovarian tumor cells, inhibits the formation of immune synapses between NK cells and ovarian tumor targets. Our results indicate that MUC16-mediated inhibition of immune synapse formation is an effective mechanism employed by ovarian tumors to evade immune recognition. Results Expression of low levels of MUC16 strongly correlated with an increased number of conjugates and activating immune synapses between ovarian tumor cells and primary naïve NK cells. MUC16-knockdown ovarian tumor cells were more susceptible to lysis by primary NK cells than MUC16 expressing controls. This increased lysis was not due to differences in the expression levels of the ligands for the activating receptors DNAM-1 and NKG2D. The NK cell leukemia cell line (NKL), which does not express KIRs but are positive for DNAM-1 and NKG2D, also conjugated and lysed MUC16-knockdown cells more efficiently than MUC16 expressing controls. Tumor cells that survived the NKL challenge expressed higher levels of MUC16 indicating selective lysis of MUC16low targets. The higher csMUC16 levels on the NKL resistant tumor cells correlated with more protection from lysis as compared to target cells that were never exposed to the effectors. Conclusion MUC16, a carrier of the tumor marker CA125, has previously been shown to facilitate ovarian tumor metastasis and inhibits NK cell mediated lysis of tumor targets. Our data now demonstrates that MUC16 expressing ovarian cancer cells are protected from recognition by NK cells. The immune protection provided by MUC16 may lead to selective survival of ovarian cancer cells that are more efficient in metastasizing within the peritoneal

  20. MUC16 provides immune protection by inhibiting synapse formation between NK and ovarian tumor cells.

    PubMed

    Gubbels, Jennifer A A; Felder, Mildred; Horibata, Sachi; Belisle, Jennifer A; Kapur, Arvinder; Holden, Helen; Petrie, Sarah; Migneault, Martine; Rancourt, Claudine; Connor, Joseph P; Patankar, Manish S

    2010-01-20

    Cancer cells utilize a variety of mechanisms to evade immune detection and attack. Effective immune detection largely relies on the formation of an immune synapse which requires close contact between immune cells and their targets. Here, we show that MUC16, a heavily glycosylated 3-5 million Da mucin expressed on the surface of ovarian tumor cells, inhibits the formation of immune synapses between NK cells and ovarian tumor targets. Our results indicate that MUC16-mediated inhibition of immune synapse formation is an effective mechanism employed by ovarian tumors to evade immune recognition. Expression of low levels of MUC16 strongly correlated with an increased number of conjugates and activating immune synapses between ovarian tumor cells and primary naïve NK cells. MUC16-knockdown ovarian tumor cells were more susceptible to lysis by primary NK cells than MUC16 expressing controls. This increased lysis was not due to differences in the expression levels of the ligands for the activating receptors DNAM-1 and NKG2D. The NK cell leukemia cell line (NKL), which does not express KIRs but are positive for DNAM-1 and NKG2D, also conjugated and lysed MUC16-knockdown cells more efficiently than MUC16 expressing controls. Tumor cells that survived the NKL challenge expressed higher levels of MUC16 indicating selective lysis of MUC16(low) targets. The higher csMUC16 levels on the NKL resistant tumor cells correlated with more protection from lysis as compared to target cells that were never exposed to the effectors. MUC16, a carrier of the tumor marker CA125, has previously been shown to facilitate ovarian tumor metastasis and inhibits NK cell mediated lysis of tumor targets. Our data now demonstrates that MUC16 expressing ovarian cancer cells are protected from recognition by NK cells. The immune protection provided by MUC16 may lead to selective survival of ovarian cancer cells that are more efficient in metastasizing within the peritoneal cavity and also at overcoming

  1. Reduced mtDNA copy number increases the sensitivity of tumor cells to chemotherapeutic drugs

    PubMed Central

    Mei, H; Sun, S; Bai, Y; Chen, Y; Chai, R; Li, H

    2015-01-01

    Many cancer drugs are toxic to cells by activating apoptotic pathways. Previous studies have shown that mitochondria have key roles in apoptosis in mammalian cells, but the role of mitochondrial DNA (mtDNA) copy number variation in the pathogenesis of tumor cell apoptosis remains largely unknown. We used the HEp-2, HNE2, and A549 tumor cell lines to explore the relationship between mtDNA copy number variation and cell apoptosis. We first induced apoptosis in three tumor cell lines and one normal adult human skin fibroblast cell line (HSF) with cisplatin (DDP) or doxorubicin (DOX) treatment and found that the mtDNA copy number significantly increased in apoptotic tumor cells, but not in HSF cells. We then downregulated the mtDNA copy number by transfection with shRNA-TFAM plasmids or treatment with ethidium bromide and found that the sensitivity of tumor cells to DDP or DOX was significantly increased. Furthermore, we observed that levels of reactive oxygen species (ROS) increased significantly in tumor cells with lower mtDNA copy numbers, and this might be related to a low level of antioxidant gene expression. Finally, we rescued the increase of ROS in tumor cells with lipoic acid or N-acetyl-L-cysteine and found that the apoptosis rate decreased. Our studies suggest that the increase of mtDNA copy number is a self-protective mechanism of tumor cells to prevent apoptosis and that reduced mtDNA copy number increases ROS levels in tumor cells, increases the tumor cells' sensitivity to chemotherapeutic drugs, and increases the rate of apoptosis. This research provides evidence that mtDNA copy number variation might be a promising new therapeutic target for the clinical treatment of tumors. PMID:25837486

  2. Molecular phenotype predicts sensitivity of squamous cell carcinoma of the head and neck to epidermal growth factor receptor inhibition.

    PubMed

    Young, Natalie R; Liu, Jing; Pierce, Carolyn; Wei, Tai-Fen; Grushko, Tatyana; Olopade, Olufunmilayo I; Liu, Wanqing; Shen, Christine; Seiwert, Tanguy Y; Cohen, Ezra E W

    2013-06-01

    Despite nearly universal expression of the wild-type epidermal growth factor receptor (EGFR) and reproducible activity of EGFR inhibitors in patients with squamous cell carcinoma of the head and neck (SCCHN), the majority of patients will not have objective responses. The mechanisms of this intrinsic resistance are not well established. We hypothesized that sensitivity to EGFR inhibitors can be predicted based on the inhibitors' effects on downstream signaling. Cell viability assays were used to assess sensitivity to the EGFR inhibitor gefitinib (ZD1839) in 8 SCCHN cell lines. Fluorescence in-situ hybridization showed the two most sensitive lines to be highly gene-amplified for EGFR. Western blotting confirmed that phosphoEGFR was inhibited at low concentrations of gefitinib in all lines tested. Phosphorylation of downstream signaling protein AKT was inhibited in sensitive lines while inhibition of phosphoERK displayed no relationship to gefitinib efficacy. Phosphatase and tensin homolog (PTEN) expression was evident in all cell lines. Activating PIK3CA mutations were found in two resistant cell lines where pAKT was not inhibited by gefitinib. In resistant cell lines harboring PIK3CA mutations, a PI3K inhibitor, LY294002, or AKT siRNA reduced cell viability with an additive effect demonstrated in combination with gefitinib. Additionally, LY294002 alone and in combination with gefitinib, was effective at treating PIK3CA mutated tumors xenografted into nude mice. Taken together this suggests that constitutively active AKT is a mechanism of intrinsic gefitinib resistance in SCCHN. This resistance can be overcome through targeting of the PI3K/AKT pathway in combination with EGFR inhibition.

  3. A thermally targeted c-Myc inhibitory polypeptide inhibits breast tumor growth.

    PubMed

    Bidwell, Gene L; Perkins, Eddie; Raucher, Drazen

    2012-06-28

    Although surgical resection with adjuvant chemotherapy and/or radiotherapy are used to treat breast tumors, normal tissue tolerance, development of metastases, and inherent tumor resistance to radiation or chemotherapy can hinder a successful outcome. We have developed a thermally responsive polypeptide, based on the sequence of Elastin-like polypeptide (ELP), that inhibits breast cancer cell proliferation by blocking the activity of the oncogenic protein c-Myc. Following systemic administration, the ELP - delivered c-Myc inhibitory peptide was targeted to tumors using focused hyperthermia, and significantly reduced tumor growth in an orthotopic mouse model of breast cancer. This work provides a new modality for targeted delivery of a specific oncogene inhibitory peptide, and this strategy may be expanded for delivery of other therapeutic peptides or small molecule drugs. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  4. Preventing inflammation inhibits biopsy-mediated changes in tumor cell behavior.

    PubMed

    Alieva, Maria; Margarido, Andreia S; Wieles, Tamara; Abels, Erik R; Colak, Burcin; Boquetale, Carla; Jan Noordmans, Herke; Snijders, Tom J; Broekman, Marike L; van Rheenen, Jacco

    2017-08-08

    Although biopsies and tumor resection are prognostically beneficial for glioblastomas (GBM), potential negative effects have also been suggested. Here, using retrospective study of patients and intravital imaging of mice, we identify some of these negative aspects, including stimulation of proliferation and migration of non-resected tumor cells, and provide a strategy to prevent these adverse effects. By repeated high-resolution intravital microscopy, we show that biopsy-like injury in GBM induces migration and proliferation of tumor cells through chemokine (C-C motif) ligand 2 (CCL-2)-dependent recruitment of macrophages. Blocking macrophage recruitment or administrating dexamethasone, a commonly used glucocorticoid to prevent brain edema in GBM patients, suppressed the observed inflammatory response and subsequent tumor growth upon biopsy both in mice and in multifocal GBM patients. Taken together, our study suggests that inhibiting CCL-2-dependent recruitment of macrophages may further increase the clinical benefits from surgical and biopsy procedures.

  5. The isoflavone metabolite 6-methoxyequol inhibits angiogenesis and suppresses tumor growth

    PubMed Central

    2012-01-01

    Background Increased consumption of plant-based diets has been linked to the presence of certain phytochemicals, including polyphenols such as flavonoids. Several of these compounds exert their protective effect via inhibition of tumor angiogenesis. Identification of additional phytochemicals with potential antiangiogenic activity is important not only for understanding the mechanism of the preventive effect, but also for developing novel therapeutic interventions. Results In an attempt to identify phytochemicals contributing to the well-documented preventive effect of plant-based diets on cancer incidence and mortality, we have screened a set of hitherto untested phytoestrogen metabolites concerning their anti-angiogenic effect, using endothelial cell proliferation as an end point. Here, we show that a novel phytoestrogen, 6-methoxyequol (6-ME), inhibited VEGF-induced proliferation of human umbilical vein endothelial cells (HUVE) cells, whereas VEGF-induced migration and survival of HUVE cells remained unaffected. In addition, 6-ME inhibited FGF-2-induced proliferation of bovine brain capillary endothelial (BBCE) cells. In line with its role in cell proliferation, 6-ME inhibited VEGF-induced phosphorylation of ERK1/2 MAPK, the key cascade responsible for VEGF-induced proliferation of endothelial cells. In this context, 6-ME inhibited in a dose dependent manner the phosphorylation of MEK1/2, the only known upstream activator of ERK1/2. 6-ME did not alter VEGF-induced phosphorylation of p38 MAPK or AKT, compatible with the lack of effect on VEGF-induced migration and survival of endothelial cells. Peri-tumor injection of 6-ME in A-431 xenograft tumors resulted in reduced tumor growth with suppressed neovasularization compared to vehicle controls (P < 0.01). Conclusions 6-ME inhibits VEGF- and FGF2-induced proliferation of ECs by targeting the phosphorylation of MEK1/2 and it downstream substrate ERK1/2, both key components of the mitogenic MAPK pathway

  6. [Inhibition of tumor growth by a peptide fusion protein binding to vascular endothelial growth factor receptor Flt-1].

    PubMed

    Lei, Hetian; Shou, Chengchao; Wu, Jian; Liu, Xiaoying; He, Luowen; Liu, Meisheng; Guo, Qi; Jiang, Beihai

    2002-10-10

    Investigating the bio-activities of peptides selected from phage display peptide library with vascular endothelial growth factor receptor Flt-1. Activities of DHFR-F56/F90 binding to human ubilial vein endothelial cells were detected by immunocytochemistry, and the activity of antiangiogenesis was determined with chick embryo chorioallantoric membrane (CAM) assay. Balb/c nude mice were used as model to detect the activity of DHFR-F56/F90 on inhibiting tumor growth, and immunohistochemistry was employed to determine the localization of the DHFR-F56/F90 in tumor. DHFR-F56/F90 can bind to HUVEC, and DHFR-F56 inhibite angiogenesis in CAM. Meanwhile DHFR-F56 can bind with tumor cells, induce tumor necrosis and inhibit tumor growth in vivo. The peptide F56 is an effective antagonist of VEGF binding to Flt-1 and has a potent utility in antiangiogenesis and inhibiting tumor growth.

  7. Phosphodiesterase 10A: a novel target for selective inhibition of colon tumor cell growth and β-catenin-dependent TCF transcriptional activity.

    PubMed

    Li, N; Lee, K; Xi, Y; Zhu, B; Gary, B D; Ramírez-Alcántara, V; Gurpinar, E; Canzoneri, J C; Fajardo, A; Sigler, S; Piazza, J T; Chen, X; Andrews, J; Thomas, M; Lu, W; Li, Y; Laan, D J; Moyer, M P; Russo, S; Eberhardt, B T; Yet, L; Keeton, A B; Grizzle, W E; Piazza, G A

    2015-03-19

    The cyclic nucleotide phosphodiesterase 10A (PDE10) has been mostly studied as a therapeutic target for certain psychiatric and neurological conditions, although a potential role in tumorigenesis has not been reported. Here we show that PDE10 is elevated in human colon tumor cell lines compared with normal colonocytes, as well as in colon tumors from human clinical specimens and intestinal tumors from Apc(Min/+) mice compared with normal intestinal mucosa, respectively. An isozyme and tumor-selective role of PDE10 were evident by the ability of small-molecule inhibitors and small interfering RNA knockdown to suppress colon tumor cell growth with reduced sensitivity of normal colonocytes. Stable knockdown of PDE10 by short hairpin RNA also inhibits colony formation and increases doubling time of colon tumor cells. PDE10 inhibition selectively activates cGMP/cGMP-dependent protein kinase signaling to suppress β-catenin levels and T-cell factor (TCF) transcriptional activity in colon tumor cells. Conversely, ectopic expression of PDE10 in normal and precancerous colonocytes increases proliferation and activates TCF transcriptional activity. These observations suggest a novel role of PDE10 in colon tumorigenesis and that inhibitors may be useful for the treatment or prevention of colorectal cancer.

  8. Phosphodiesterase 10A: a novel target for selective inhibition of colon tumor cell growth and β-catenin-dependent TCF transcriptional activity

    PubMed Central

    Li, Nan; Lee, Kevin; Xi, Yaguang; Zhu, Bing; Gary, Bernard D.; Ramírez-Alcántara, Verónica; Gurpinar, Evrim; Canzoneri, Joshua C.; Fajardo, Alexandra; Sigler, Sara; Piazza, John T.; Chen, Xi; Andrews, Joel; Thomas, Meagan; Lu, Wenyan; Li, Yonghe; Laan, Danuel J.; Moyer, Mary P.; Russo, Suzanne; Eberhardt, Brian T.; Yet, Larry; Keeton, Adam B.; Grizzle, William E.; Piazza, Gary A.

    2014-01-01

    The cyclic nucleotide phosphodiesterase10A (PDE10) has been mostly studied as a therapeutic target for certain psychiatric and neurological conditions, although a potential role in tumorigenesis has not been reported. Here we show that PDE10 is elevated in human colon tumor cell lines compared with normal colonocytes, as well as in colon tumors from human clinical specimens and intestinal tumors from ApcMin/+ mice compared with normal intestinal mucosa, respectively. An isozyme and tumor-selective role of PDE10 was evident by the ability of small molecule inhibitors and siRNA knockdown to suppress colon tumor cell growth with reduced sensitivity of normal colonocytes. Stable knockdown of PDE10 by shRNA also inhibits colony formation and increases doubling time of colon tumor cells. PDE10 inhibition selectively activates cGMP/PKG signaling to suppress β-catenin levels and T-cell factor (TCF) transcriptional activity in colon tumor cells. Conversely, ectopic expression of PDE10 in normal and precancerous colonocytes increases proliferation and activates TCF transcriptional activity. These observations suggest a novel role of PDE10 in colon tumorigenesis and that inhibitors may be useful for the treatment or prevention of colorectal cancer. PMID:24704829

  9. Interferon and hormone sensitivity of endocrine-related tumors.

    PubMed

    Sica, G; Iacopino, F; Recchia, F

    1996-02-01

    Interferons (IFNs) have been shown to enhance both in vitro and in vivo the antiproliferative activity of some hormones and anti-hormones which mainly act via steroid receptors. We discuss some of the mechanisms which could be involved in determining this effect in breast, endometrial and prostatic cancer cells, with a particular emphasis on steroid receptor modulation, reduction of the expression of epidermal growth factor receptors and, finally, down-regulation of some oncogenes. It seems that under appropriate conditions IFN might produce changes in cancer cells that enhance or restore hormone sensitivity. Nevertheless, available clinical data are too few to allow any conclusion to be drawn and this problem merits further investigations.

  10. Combined therapy with cyclophosphamide and DNA preparation inhibits the tumor growth in mice

    PubMed Central

    Alyamkina, Ekaterina A; Dolgova, Evgenia V; Likhacheva, Anastasia S; Rogachev, Vladimir A; Sebeleva, Tamara E; Nikolin, Valeriy P; Popova, Nelly A; Orishchenko, Konstantin E; Strunkin, Dmitriy N; Chernykh, Elena R; Zagrebelniy, Stanislav N; Bogachev, Sergei S; Shurdov, Mikhail A

    2009-01-01

    Background When cyclophosphamide and preparations of fragmented exogenous genomic double stranded DNA were administered in sequence, the regressive effect on the tumor was synergic: this combined treatment had a more pronounced effect than cyclophosphamide alone. Our further studies demonstrated that exogenous DNA stimulated the maturation and specific activities of dendritic cells. This suggests that cyclophosphamide, combined with DNA, leads to an immune response to the tumors that were grafted into the subjects post treatment. Methods Three-month old CBA/Lac mice were used in the experiments. The mice were injected with cyclosphamide (200 mkg per 1 kg body weight) and genomic DNA (of human, mouse or salmon sperm origin). The DNA was administered intraperitoneally or subcutaneously. After 23 to 60 days, one million tumor cells were intramuscularly grafted into the mice. In the final experiment, the mice were pre-immunized by subcutaneous injections of 20 million repeatedly thawed and frozen tumor cells. Changes in tumor growth were determined by multiplying the three perpendicular diameters (measured by caliper). Students' t-tests were used to determine the difference between tumor growth and average survival rate between the mouse groups and the controls. Results An analysis of varying treatments with cyclophosphamide and exogenous DNA, followed by tumor grafting, provided evidence that this combined treatment had an immunizing effect. This inhibitory effect in mice was analyzed in an experiment with the classical immunization of a tumor homogenate. The strongest inhibitory action on a transplanted graft was created through the following steps: cyclophosphamide at 200 mg/kg of body weight administered as a pretreatment; 6 mg fragmented exogenous DNA administered over the course of 3 days; tumor homogenate grafted 10 days following the final DNA injection. Conclusion Fragmented exogenous DNA injected with cyclophosphamide inhibits the growth of tumors that are

  11. Gefitinib selectively inhibits tumor cell migration in EGFR-amplified human glioblastoma.

    PubMed

    Parker, Jonathon J; Dionne, Kalen R; Massarwa, Rada; Klaassen, Marci; Foreman, Nicholas K; Niswander, Lee; Canoll, Peter; Kleinschmidt-Demasters, B K; Waziri, Allen

    2013-08-01

    Tissue invasion is a hallmark of most human cancers and remains a major source of treatment failure in patients with glioblastoma (GBM). Although EGFR amplification has been previously associated with more invasive tumor behavior, existing experimental models have not supported quantitative evaluation of interpatient differences in tumor cell migration or testing of patient-specific responses to therapies targeting invasion. To explore these questions, we optimized an ex vivo organotypic slice culture system allowing for labeling and tracking of tumor cells in human GBM slice cultures. With use of time-lapse confocal microscopy of retrovirally labeled tumor cells in slices, baseline differences in migration speed and efficiency were determined and correlated with EGFR amplification in a cohort of patients with GBM. Slices were treated with gefitinib to evaluate anti-invasive effects associated with targeting EGFR. Migration analysis identified significant patient-to-patient variation at baseline. EGFR amplification was correlated with increased migration speed and efficiency compared with nonamplified tumors. Critically, gefitinib resulted in a selective and significant reduction of tumor cell migration in EGFR-amplified tumors. These data provide the first identification of patient-to-patient variation in tumor cell migration in living human tumor tissue. We found that EGFR-amplified GBM are inherently more efficient in their migration and can be effectively targeted by gefitinib treatment. These data suggest that stratified clinical trails are needed to evaluate gefitinib as an anti-invasive adjuvant for patients with EGFR-amplified GBM. In addition, these results provide proof of principle that primary slice cultures may be useful for patient-specific screening of agents designed to inhibit tumor invasion.

  12. Hair follicle-derived blood vessels vascularize tumors in skin and are inhibited by Doxorubicin.

    PubMed

    Amoh, Yasuyuki; Li, Lingna; Yang, Meng; Jiang, Ping; Moossa, Abdool R; Katsuoka, Kensei; Hoffman, Robert M

    2005-03-15

    We have recently shown that the neural-stem cell marker nestin is expressed in hair follicle stem cells and the blood vessel network interconnecting hair follicles in the skin of transgenic mice with nestin regulatory element-driven green fluorescent protein (ND-GFP). The hair follicles were shown to give rise to the nestin-expressing blood vessels in the skin. In the present study, we visualized tumor angiogenesis by dual-color fluorescence imaging in ND-GFP transgenic mice after transplantation of the murine melanoma cell line B16F10 expressing red fluorescent protein. ND-GFP was highly expressed in proliferating endothelial cells and nascent blood vessels in the growing tumor. Results of immunohistochemical staining showed that the blood vessel-specific antigen CD31 was expressed in ND-GFP-expressing nascent blood vessels. ND-GFP expression was diminished in the vessels with increased blood flow. Progressive angiogenesis during tumor growth was readily visualized during tumor growth by GFP expression. Doxorubicin inhibited the nascent tumor angiogenesis as well as tumor growth in the ND-GFP mice transplanted with B16F10-RFP. This model is useful for direct visualization of tumor angiogenesis and evaluation of angiogenic inhibitors.

  13. Arctigenin preferentially induces tumor cell death under glucose deprivation by inhibiting cellular energy metabolism.

    PubMed

    Gu, Yuan; Qi, Chunting; Sun, Xiaoxiao; Ma, Xiuquan; Zhang, Haohao; Hu, Lihong; Yuan, Junying; Yu, Qiang

    2012-08-15

    Selectively eradicating cancer cells with minimum adverse effects on normal cells is a major challenge in the development of anticancer therapy. We hypothesize that nutrient-limiting conditions frequently encountered by cancer cells in poorly vascularized solid tumors might provide an opportunity for developing selective therapy. In this study, we investigated the function and molecular mechanisms of a natural compound, arctigenin, in regulating tumor cell growth. We demonstrated that arctigenin selectively promoted glucose-starved A549 tumor cells to undergo necrosis by inhibiting mitochondrial respiration. In doing so, arctigenin elevated cellular level of reactive oxygen species (ROS) and blocked cellular energy metabolism in the glucose-starved tumor cells. We also demonstrated that cellular ROS generation was caused by intracellular ATP depletion and played an essential role in the arctigenin-induced tumor cell death under the glucose-limiting condition. Furthermore, we combined arctigenin with the glucose analogue 2-deoxyglucose (2DG) and examined their effects on tumor cell growth. Interestingly, this combination displayed preferential cell-death inducing activity against tumor cells compared to normal cells. Hence, we propose that the combination of arctigenin and 2DG may represent a promising new cancer therapy with minimal normal tissue toxicity. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  14. MIF Maintains the Tumorigenic Capacity of Brain Tumor-Initiating Cells by Directly Inhibiting p53.

    PubMed

    Fukaya, Raita; Ohta, Shigeki; Yaguchi, Tomonori; Matsuzaki, Yumi; Sugihara, Eiji; Okano, Hideyuki; Saya, Hideyuki; Kawakami, Yutaka; Kawase, Takeshi; Yoshida, Kazunari; Toda, Masahiro

    2016-05-01

    Tumor-initiating cells thought to drive brain cancer are embedded in a complex heterogeneous histology. In this study, we isolated primary cells from 21 human brain tumor specimens to establish cell lines with high tumorigenic potential and to identify the molecules enabling this capability. The morphology, sphere-forming ability upon expansion, and differentiation potential of all cell lines were indistinguishable in vitro However, testing for tumorigenicity revealed two distinct cell types, brain tumor-initiating cells (BTIC) and non-BTIC. We found that macrophage migration inhibitory factor (MIF) was highly expressed in BTIC compared with non-BTIC. MIF bound directly to both wild-type and mutant p53 but regulated p53-dependent cell growth by different mechanisms, depending on glioma cell line and p53 status. MIF physically interacted with wild-type p53 in the nucleus and inhibited its transcription-dependent functions. In contrast, MIF bound to mutant p53 in the cytoplasm and abrogated transcription-independent induction of apoptosis. Furthermore, MIF knockdown inhibited BTIC-induced tumor formation in a mouse xenograft model, leading to increased overall survival. Collectively, our findings suggest that MIF regulates BTIC function through direct, intracellular inhibition of p53, shedding light on the molecular mechanisms underlying the tumorigenicity of certain malignant brain cells. Cancer Res; 76(9); 2813-23. ©2016 AACR. ©2016 American Association for Cancer Research.

  15. Mo polyoxometalate nanoparticles inhibit tumor growth and vascular endothelial growth factor induced angiogenesis

    NASA Astrophysics Data System (ADS)

    Zheng, Wenjing; Yang, Licong; Liu, Ying; Qin, Xiuying; Zhou, Yanhui; Zhou, Yunshan; Liu, Jie

    2014-06-01

    Tumor growth depends on angiogenesis, which can furnish the oxygen and nutrients that proliferate tumor cells. Thus, blocking angiogenesis can be an effective strategy to inhibit tumor growth. In this work, three typical nanoparticles based on polyoxometalates (POMs) have been prepared; we investigated their capability as antitumor and anti-angiogenesis agents. We found that Mo POM nanoparticles, especially complex 3, inhibited the growth of human hepatocellular liver carcinoma cells (HepG2) through cellular reactive oxygen species levels’ elevation and mitochondrial membrane potential damage. Complex 3 also suppressed the proliferation, migration, and tube formation of endothelial cells in vitro and chicken chorioallantoic membrane development ex vivo. Furthermore, western blot analysis of cell signaling molecules indicated that Mo POMs blocked the vascular endothelial growth factor receptor 2-mediated ERK1/2 and AKT signaling pathways in endothelial cells. Using transmission electron microscopy, we demonstrated their cellular uptake and localization within the cytoplasm of HepG2 cells. These results indicate that, owing to the extraordinary physical and chemical properties, Mo POM nanoparticles can significantly inhibit tumor growth and angiogenesis, which makes them potential drug candidates in anticancer and anti-angiogenesis therapies.

  16. Pterostilbene acts through metastasis-associated protein 1 to inhibit tumor growth, progression and metastasis in prostate cancer.

    PubMed

    Li, Kun; Dias, Steven J; Rimando, Agnes M; Dhar, Swati; Mizuno, Cassia S; Penman, Alan D; Lewin, Jack R; Levenson, Anait S

    2013-01-01

    The development of natural product agents with targeted strategies holds promise for enhanced anticancer therapy with reduced drug-associated side effects. Resveratrol found in red wine, has anticancer activity in various tumor types. We reported earlier on a new molecular target of resveratrol, the metastasis-associated protein 1 (MTA1), which is a part of nucleosome remodeling and deacetylation (NuRD) co-repressor complex that mediates gene silencing. We identified resveratrol as a regulator of MTA1/NuRD complex and re-activator of p53 acetylation in prostate cancer (PCa). In the current study, we addressed whether resveratrol analogues also possess the ability to inhibit MTA1 and to reverse p53 deacetylation. We demonstrated that pterostilbene (PTER), found in blueberries, had greater increase in MTA1-mediated p53 acetylation, confirming superior potency over resveratrol as dietary epigenetic agent. In orthotopic PCa xenografts, resveratrol and PTER significantly inhibited tumor growth, progression, local invasion and spontaneous metastasis. Furthermore, MTA1-knockdown sensitized cells to these agents resulting in additional reduction of tumor progression and metastasis. The reduction was dependent on MTA1 signaling showing increased p53 acetylation, higher apoptotic index and less angiogenesis in vivo in all xenografts treated with the compounds, and particularly with PTER. Altogether, our results indicate MTA1 as a major contributor in prostate tumor malignant progression, and support the use of strategies targeting MTA1. Our strong pre-clinical data indicate PTER as a potent, selective and pharmacologically safe natural product that may be tested in advanced PCa.

  17. Pterostilbene Acts through Metastasis-Associated Protein 1 to Inhibit Tumor Growth, Progression and Metastasis in Prostate Cancer

    PubMed Central

    Rimando, Agnes M.; Dhar, Swati; Mizuno, Cassia S.; Penman, Alan D.; Lewin, Jack R.; Levenson, Anait S.

    2013-01-01

    The development of natural product agents with targeted strategies holds promise for enhanced anticancer therapy with reduced drug-associated side effects. Resveratrol found in red wine, has anticancer activity in various tumor types. We reported earlier on a new molecular target of resveratrol, the metastasis-associated protein 1 (MTA1), which is a part of nucleosome remodeling and deacetylation (NuRD) co-repressor complex that mediates gene silencing. We identified resveratrol as a regulator of MTA1/NuRD complex and re-activator of p53 acetylation in prostate cancer (PCa). In the current study, we addressed whether resveratrol analogues also possess the ability to inhibit MTA1 and to reverse p53 deacetylation. We demonstrated that pterostilbene (PTER), found in blueberries, had greater increase in MTA1-mediated p53 acetylation, confirming superior potency over resveratrol as dietary epigenetic agent. In orthotopic PCa xenografts, resveratrol and PTER significantly inhibited tumor growth, progression, local invasion and spontaneous metastasis. Furthermore, MTA1-knockdown sensitized cells to these agents resulting in additional reduction of tumor progression and metastasis. The reduction was dependent on MTA1 signaling showing increased p53 acetylation, higher apoptotic index and less angiogenesis in vivo in all xenografts treated with the compounds, and particularly with PTER. Altogether, our results indicate MTA1 as a major contributor in prostate tumor malignant progression, and support the use of strategies targeting MTA1. Our strong pre-clinical data indicate PTER as a potent, selective and pharmacologically safe natural product that may be tested in advanced PCa. PMID:23469203

  18. Inhibition of never in mitosis A (NIMA)-related kinase-4 reduces survivin expression and sensitizes cancer cells to TRAIL-induced cell death.

    PubMed

    Park, So Jung; Jo, Doo Sin; Jo, Se-Young; Shin, Dong Woon; Shim, Sangmi; Jo, Yoon Kyung; Shin, Ji Hyun; Ha, Ye Jin; Jeong, Seong-Yun; Hwang, Jung Jin; Kim, Young Sam; Suh, Young-Ah; Chang, Jong Wook; Kim, Jin Cheon; Cho, Dong-Hyung

    2016-10-04

    The tumor necrosis factor-related apoptosis inducing ligand (TRAIL) preferentially induces apoptosis in cancer cells. However, many tumors are resistant to TRAIL-induced apoptosis, and resistance mechanisms are not fully understood. To identify novel regulatory molecules of TRAIL resistance, we screened a siRNA library targeting the human kinome, and NEK4 (NIMA-related kinase-4) was identified. Knockdown of NEK4 sensitized TRAIL-resistant cancer cells and in vivo xenografts to cell death. In contrast, over expression of NEK4 suppressed TRAIL-induced cell death in TRAIL-sensitive cancer cells. In addition, loss of NEK4 resulted in decrease of the anti-apoptotic protein survivin, but an increase in apoptotic cell death. Interestingly, NEK4 was highly upregulated in tumor tissues derived from patients with lung cancer and colon cancer. These results suggest that inhibition of NEK4 sensitizes cancer cells to TRAIL-induced apoptosis by regulation of survivin expression.

  19. Inhibition of never in mitosis A (NIMA)-related kinase-4 reduces survivin expression and sensitizes cancer cells to TRAIL-induced cell death

    PubMed Central

    Park, So Jung; Jo, Doo Sin; Jo, Se-Young; Shin, Dong Woon; Shim, Sangmi; Jo, Yoon Kyung; Shin, Ji Hyun; Ha, Ye Jin; Jeong, Seong-Yun; Hwang, Jung Jin; Kim, Young Sam; Suh, Young-Ah; Chang, Jong Wook; Kim, Jin Cheon; Cho, Dong-Hyung

    2016-01-01

    The tumor necrosis factor-related apoptosis inducing ligand (TRAIL) preferentially induces apoptosis in cancer cells. However, many tumors are resistant to TRAIL-induced apoptosis, and resistance mechanisms are not fully understood. To identify novel regulatory molecules of TRAIL resistance, we screened a siRNA library targeting the human kinome, and NEK4 (NIMA-related kinase-4) was identified. Knockdown of NEK4 sensitized TRAIL-resistant cancer cells and in vivo xenografts to cell death. In contrast, over expression of NEK4 suppressed TRAIL-induced cell death in TRAIL-sensitive cancer cells. In addition, loss of NEK4 resulted in decrease of the anti-apoptotic protein survivin, but an increase in apoptotic cell death. Interestingly, NEK4 was highly upregulated in tumor tissues derived from patients with lung cancer and colon cancer. These results suggest that inhibition of NEK4 sensitizes cancer cells to TRAIL-induced apoptosis by regulation of survivin expression. PMID:27602754

  20. An implantable microdevice to perform high-throughput in vivo drug sensitivity testing in tumors

    PubMed Central

    Jonas, Oliver; Landry, Heather M.; Fuller, Jason E.; Santini, John T.; Baselga, Jose; Tepper, Robert I.; Cima, Michael J.; Langer, Robert

    2016-01-01

    Current anticancer chemotherapy relies on a limited set of in vitro or indirect prognostic markers of tumor response to available drugs. A more accurate analysis of drug sensitivity would involve studying tumor response in vivo. To this end, we have developed an implantable device that can perform drug sensitivity testing of several anticancer agents simultaneously inside the living tumor. The device contained reservoirs that released microdoses of single agents or drug combinations into spatially distinct regions of the tumor. The local drug concentrations were chosen to be representative of concentrations achieved during systemic treatment. Local efficacy and drug concentration profiles were evaluated for each drug or drug combination on the device, and the local efficacy was confirmed to be a predictor of systemic efficacy in vivo for multiple drugs and tumor models. Currently, up to 16 individual drugs or combinations can be assessed independently, without systemic drug exposure, through minimally invasive biopsy of a small region of a single tumor. This assay takes into consideration physiologic effects that contribute to drug response by allowing drugs to interact with the living tumor in its native microenvironment. Because these effects are crucial to predicting drug response, we envision that these devices will help identify optimal drug therapy before systemic treatment is initiated and could improve drug response prediction beyond the biomarkers and in vitro and ex vivo studies used today. These devices may also be used in clinical drug development to safely gather efficacy data on new compounds before pharmacological optimization. PMID:25904741

  1. Inhibition of the Wnt/β-catenin signaling pathway improves the anti-tumor effects of sorafenib against hepatocellular carcinoma.

    PubMed

    Lin, Hsiao-Hui; Feng, Wen-Chi; Lu, Li-Chun; Shao, Yu-Yun; Hsu, Chih-Hung; Cheng, Ann-Lii

    2016-10-10

    Sorafenib, a multikinase inhibitor, is currently the only approved drug for advanced hepatocellular carcinoma (HCC). The current study tested the hypothesis whether inhibition of the Wnt/β-catenin signaling pathway could improve the anti-tumor effects of sorafenib in HCC. ICG-001, a small molecule which blocks the interaction of β-catenin with its transcriptional coactivator CBP, dose-dependently enhanced the growth-suppressive and apoptosis-induction effects of sorafenib in multiple HCC cell lines. Downregulation of β-catenin by RNA interference increased sorafenib sensitivity, whereas overexpression of β-catenin reduced sorafenib sensitivity in Huh7 cells. The sorafenib-sensitization effect of short hairpin RNA (shRNA)-mediated β-catenin downregulation in Huh7 cells was attenuated by β-catenin overexpression. Mechanistically, sorafenib combined with ICG-001 or shRNA-mediated β-catenin downregulation augmented the induction of apoptosis, and resulted in a significant downregulation of Mcl-1 in HCC cells. In Huh7 cell mouse xenograft model, the combination of ICG-001 and sorafenib showed a more significant growth-retarding effect than single agent treatment of sorafenib or ICG-001. Our data indicate that inhibition of the Wnt/β-catenin signaling pathway improves the antitumor effects of sorafenib against HCC in vitro and in vivo. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. Honokiol thwarts gastric tumor growth and peritoneal dissemination by inhibiting Tpl2 in an orthotopic model.

    PubMed

    Pan, Hung-Chuan; Lai, De-Wei; Lan, Keng-Hsin; Shen, Chin-Chang; Wu, Sheng-Mao; Chiu, Chien-Shan; Wang, Keh-Bin; Sheu, Meei-Ling

    2013-11-01

    Honokiol is known to suppress the growth of cancer cells; however, to date, its antiperitoneal dissemination effects have not been studied in an orthotopic mouse model. In the present study, we evaluated the antiperitoneal dissemination potential of Honokiol in an orthotopic mouse model and assessed associations with tumor growth factor-β1 (TGFβ1) and cells stimulated by a carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Our results demonstrate that tumor growth, peritoneal dissemination and peritoneum or organ metastasis of orthotopically implanted MKN45 cells were significantly decreased in Honokiol-treated mice and that endoplasmic reticulum (ER) stress was induced. Honokiol-treated tumors showed increased epithelial signatures such as E-cadherin, cytokeratin-18 and ER stress marker. In contrast, decreased expression of vimentin, Snail and tumor progression locus 2 (Tpl2) was also noted. TGFβ1 and MNNG-induced downregulation of E-cadherin and upregulation of Tpl2 were abrogated by Honokiol treatment. The effect of Tpl2 inhibition in cancer cells or endothelial cells was associated with inactivation of CCAAT/enhancer binding protein B, nuclear factor kappa-light-chain-enhancer of activated B cell and activator protein-1 and suppression of vascular endothelial growth factor. Inhibition of Tpl2 in gastric cancer cells by small interfering RNA or pharmacological inhibitor was found to effectively reduce growth ability and vessel density in vivo. Honokiol-induced reversal of epithelial-to-mesenchymal transition (EMT) and ER stress-induced apoptosis via Tp12 may involve the paralleling processes. Taken together, our results suggest that the therapeutic inhibition of Tpl2 by Honokiol thwarts both gastric tumor growth and peritoneal dissemination by inducing ER stress and inhibiting EMT.

  3. Telomerase inhibition abolishes the tumorigenicity of pediatric ependymoma tumor-initiating cells.

    PubMed

    Barszczyk, Mark; Buczkowicz, Pawel; Castelo-Branco, Pedro; Mack, Stephen C; Ramaswamy, Vijay; Mangerel, Joshua; Agnihotri, Sameer; Remke, Marc; Golbourn, Brian; Pajovic, Sanja; Elizabeth, Cynthia; Yu, Man; Luu, Betty; Morrison, Andrew; Adamski, Jennifer; Nethery-Brokx, Kathleen; Li, Xiao-Nan; Van Meter, Timothy; Dirks, Peter B; Rutka, James T; Taylor, Michael D; Tabori, Uri; Hawkins, Cynthia

    2014-12-01

    Pediatric ependymomas are highly recurrent tumors resistant to conventional chemotherapy. Telomerase, a ribonucleoprotein critical in permitting limitless replication, has been found to be critically important for the maintenance of tumor-initiating cells (TICs). These TICs are chemoresistant, repopulate the tumor from which they are identified, and are drivers of recurrence in numerous cancers. In this study, telomerase enzymatic activity was directly measured and inhibited to assess the therapeutic potential of targeting telomerase. Telomerase repeat amplification protocol (TRAP) (n = 36) and C-circle assay/telomere FISH/ATRX staining (n = 76) were performed on primary ependymomas to determine the prevalence and prognostic potential of telomerase activity or alternative lengthening of telomeres (ALT) as telomere maintenance mechanisms, respectively. Imetelstat, a phase 2 telomerase inhibitor, was used to elucidate the effect of telomerase inhibition on proliferation and tumorigenicity in established cell lines (BXD-1425EPN, R254), a primary TIC line (E520) and xenograft models of pediatric ependymoma. Over 60 % of pediatric ependymomas were found to rely on telomerase activity to maintain telomeres, while no ependymomas showed evidence of ALT. Children with telomerase-active tumors had reduced 5-year progression-free survival (29 ± 11 vs 64 ± 18 %; p = 0.03) and overall survival (58 ± 12 vs 83 ± 15 %; p = 0.05) rates compared to those with tumors lacking telomerase activity. Imetelstat inhibited proliferation and self-renewal by shortening telomeres and inducing senescence in vitro. In vivo, Imetelstat significantly reduced subcutaneous xenograft growth by 40 % (p = 0.03) and completely abolished the tumorigenicity of pediatric ependymoma TICs in an orthotopic xenograft model. Telomerase inhibition represents a promising therapeutic approach for telomerase-active pediatric ependymomas found to characterize high-risk ependymomas.

  4. Oridonin Inhibits Tumor Growth and Metastasis through Anti-Angiogenesis by Blocking the Notch Signaling

    PubMed Central

    Li, Jingjie; Deng, Huayun; Song, Yajuan; Zhai, Dong; Peng, Yi; Lu, Xiaoling; Liu, Mingyao; Zhao, Yongxiang; Yi, Zhengfang

    2014-01-01

    While significant progress has been made in understanding the anti-inflammatory and anti-proliferative effects of the natural diterpenoid component Oridonin on tumor cells, little is known about its effect on tumor angiogenesis or metastasis and on the underlying molecular mechanisms. In this study, Oridonin significantly suppressed human umbilical vascular endothelial cells (HUVECs) proliferation, migration, and apillary-like structure formation in vitro. Using aortic ring assay and mouse corneal angiogenesis model, we found that Oridonin inhibited angiogenesis ex vivo and in vivo. In our animal experiments, Oridonin impeded tumor growth and metastasis. Immunohistochemistry analysis further revealed that the expression of CD31 and vWF protein in xenografts was remarkably decreased by the Oridonin. Furthermore, Oridonin reinforced endothelial cell-cell junction and impaired breast cancer cell transendothelial migration. Mechanistically, Oridonin not only down-regulated Jagged2 expression and Notch1 activity but also decreased the expression of their target genes. In conclusion, our results demonstrated an original role of Oridonin in inhibiting tumor angiogenesis and propose a mechanism. This study also provides new evidence supporting the central role of Notch in tumor angiogenesis and suggests that Oridonin could be a potential drug candidate for angiogenesis related diseases. PMID:25485753

  5. Akt inhibition enhances expansion of potent tumor-specific lymphocytes with memory cell characteristics

    PubMed Central

    Crompton, Joseph G.; Sukumar, Madhusudhanan; Roychoudhuri, Rahul; Clever, David; Gros, Alena; Eil, Robert; Tran, Eric; Hanada, Ken-ichi; Yu, Zhiya; Palmer, Douglas C.; Kerkar, Sid P.; Michalek, Ryan D.; Upham, Trevor; Leonardi, Anthony; Aquavella, Nicholas; Wang, Ena; Marincola, Francesco M.; Gattinoni, Luca; Muranski, Pawel; Sundrud, Mark S.; Klebanoff, Christopher A.; Rosenberg, Steven A.; Fearon, Douglas T.; Restifo, Nicholas P.

    2015-01-01

    Adoptive cell therapy (ACT) using autologous tumor-infiltrating lymphocytes (TIL) can result in complete regression of advanced cancer in some patients, but the efficacy of this potentially curative therapy might be limited by poor persistence of TIL after adoptive-transfer. Pharmacologic inhibition of the serine/threonine kinase Akt has recently been shown to promote immunologic memory in viral-specific murine models, but whether this approach may enhance features of memory (e.g. long-term persistence) in TIL which are characteristically exhausted and senescent is not established. Here we show that pharmacologic inhibition of Akt enables expansion of TIL with the transcriptional, metabolic and functional properties characteristic of memory T cells. Consequently, Akt inhibition results in enhanced persistence of TIL after adoptive transfer into an immunodeficient animal model and augments anti-tumor immunity of CD8 T cells in a mouse model of cell-based immunotherapy. Pharmacologic inhibition of Akt represents a novel immunometabolomic approach to enhance the persistence of anti-tumor T cells and improve the efficacy of cell-based immunotherapy for metastatic cancer. PMID:25432172

  6. DCT015, a new sorafenib derivate, inhibits tumor growth and angiogenesis in gastric cancer models.

    PubMed

    Wang, Wenyan; Wang, Hui; Ni, Yingying; Yao, Zhenming; Ye, Liang; Tian, Jingwei

    2016-07-01

    The objective of this study is to investigate antiproliferative activities against gastric cancer and anti-angiogenesis of DCT015, a novel sorafenib derivate, and potential mechanisms. The effects of DCT015 on proliferation and apoptosis in gastric cancer cells were evaluated by cytotoxicity assays, apoptosis analysis, flow cytometry analysis, and Western blotting assays. The in vivo antitumor effects were carried out in nude mice bearing gastric cancer. On the other hand, the anti-angiogenesis effects of DCT015 were measured by human umbilical vein endothelial cell (HUVEC) proliferation, migration, tube formation, and Western blotting analysis. The results showed that DCT015 inhibited the proliferation, induced the morphological changes of apoptosis, and increased the apoptosis percentage, as well as increased the "sub-G1" population in gastric cancer cells. DCT015 also significantly decreased the tumor volumes and tumor weights in vivo by oral administration. Immunohistochemistry assay demonstrated that DCT015 inhibited tumor growth and neovascularization. In vitro studies found that DCT015 inhibited both MEK/ERK and PI3K/Akt signaling pathways by Western blotting assays. Moreover, DCT015 significantly inhibited VEGF-induced migration and tube formation in HUVECs. Western blotting analysis showed that DCT015 downregulated VEGF-induced VEGFR2 phosphorylation with the decreased phosphorylation of the downstream key proteins. Taken together, our findings highlight that DCT015 is a promising orally anticancer drug for treating gastric cancer.

  7. Competitive but Not Allosteric mTOR Kinase Inhibition Enhances Tumor Cell Radiosensitivity1

    PubMed Central

    Hayman, Thomas J; Kramp, Tamalee; Kahn, Jenna; Jamal, Muhammad; Camphausen, Kevin; Tofilon, Philip J

    2013-01-01

    The mechanistic target of rapamycin (mTOR) is a critical kinase in the regulation of gene translation and has been suggested as a potential target for radiosensitization. The goal of this study was to compare the radiosensitizing activities of the allosteric mTOR inhibitor rapamycin with that of the competitive mTOR inhibitor PP242. On the basis of immunoblot analyses, whereas rapamycin only partially inhibited mTOR complex 1 (mTORC1) activity and had no effect on mTOR complex 2 (mTORC2), PP242 inhibited the activity of both mTOR-containing complexes. Irradiation alone had no effect on mTORC1 or mTORC2 activity. Clonogenic survival was used to define the effects of the mTOR inhibitors on in vitro radiosensitivity. In the two tumor cell lines evaluated, PP242 treatment 1 hour before irradiation increased radiosensitivity, whereas rapamycin had no effect. Addition of PP242 after irradiation also enhanced the radiosensitivity of both tumor lines. To investigate the mechanism of radiosensitization, the induction and repair of DNA double-strand breaks were evaluated according γH2AX foci. PP242 exposure did not influence the initial level of γH2AX foci after irradiation but did significantly delay the dispersal of radiation-induced γH2AX foci. In contrast to the tumor cell lines, the radiosensitivity of a normal human fibroblast cell line was not influenced by PP242. Finally, PP242 administration to mice bearing U251 xenografts enhanced radiation-induced tumor growth delay. These results indicate that in a preclinical tumor model PP242 enhances tumor cell radiosensitivity both in vitro and in vivo and suggest that this effect involves an inhibition of DNA repair. PMID:23730416

  8. Emodin inhibits breast cancer growth by blocking the tumor-promoting feedforward loop between cancer cells and macrophages

    PubMed Central

    Iwanowycz, Stephen; Wang, Junfeng; Hodge, Johnie; Wang, Yuzhen; Yu, Fang; Fan, Daping

    2016-01-01

    Macrophage infiltration correlates with severity in many types of cancer. Tumor cells recruit macrophages and educate them to adopt an M2-like phenotype through the secretion of chemokines and growth factors, such as MCP1 and CSF1. Macrophages in turn promote tumor growth through supporting angiogenesis, suppressing anti-tumor immunity, modulating extracellular matrix remodeling, and promoting tumor cell migration. Thus tumor cells and macrophages interact to create a feedforward loop supporting tumor growth and metastasis. In this study, we tested the ability of emodin, a Chinese herb-derived compound, to inhibit breast cancer growth in mice and examined the underlying mechanisms. Emodin was used to treat mice bearing EO771 or 4T1 breast tumors. It was shown that emodin attenuated tumor growth by inhibiting macrophage infiltration and M2-like polarization, accompanied by increased T cell activation and reduced angiogenesis in tumors. The tumor inhibitory effects of emodin were lost in tumor-bearing mice with macrophage depletion. Emodin inhibited IRF4, STAT6, and C/EBPβ signaling and increased inhibitory histone H3 lysine 27 tri-methylation (H3K27m3) on the promoters of M2 related genes in tumor-associated macrophages. In addition, emodin inhibited tumor cell secretion of MCP1and CSF1, as well as expression of surface anchoring molecule Thy-1, thus suppressing macrophage migration towards and adhesion to tumor cells. These results suggest that emodin acts on both breast cancer cells and macrophages and effectively blocks the tumor-promoting feedforward loop between the two cell types, thereby inhibiting breast cancer growth and metastasis. PMID:27196773

  9. Tumor flare after start of RAF inhibition in KRAS mutated NSCLC: a case report.

    PubMed

    Mellema, Wouter W; Burgers, Sjaak A; Smit, Egbert F

    2015-02-01

    Here we describe a case of striking tumor flare after start of treatment with sorafenib and metformin as part of a phase II clinical trial. Previous reports have described a paradoxal activation of the MAPK pathway after treatment with a weak RAF inhibitor. This mechanism is based on inhibition of a negative feedback loop to upstream effectors of RAF and subsequently increased stimulation of the RAS-RAF-MEK-ERK (MAPK) pathway. We suggest that sorafenib may contribute to tumor progression through this mechanism and clinicians should be aware of this phenomenon when treating NSCLC patients with sorafenib. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Efficacy of liposomal curcumin in a human pancreatic tumor xenograft model: inhibition of tumor growth and angiogenesis.

    PubMed

    Ranjan, Amalendu P; Mukerjee, Anindita; Helson, Lawrence; Gupta, Rohan; Vishwanatha, Jamboor K

    2013-09-01

    Liposome-based drug delivery has been successful in the past decade, with some formulations being Food and Drug Administration (FDA)-approved and others in clinical trials around the world. The major disadvantage associated with curcumin, a potent anticancer agent, is its poor aqueous solubility and hence low systemic bioavailability. However, curcumin can be encapsulated into liposomes to improve systemic bioavailability. We determined the antitumor effects of a liposomal curcumin formulation against human MiaPaCa pancreatic cancer cells both in vitro and in xenograft studies. Histological sections were isolated from murine xenografts and immunohistochemistry was performed. The in vitro (IC50) liposomal curcumin proliferation-inhibiting concentration was 17.5 μM. In xenograft tumors in nude mice, liposomal curcumin at 20 mg/kg i.p. three-times a week for four weeks induced 42% suppression of tumor growth compared to untreated controls. A potent antiangiogenic effect characterized by a reduced number of blood vessels and reduced expression of vascular endothelial growth factor and annexin A2 proteins, as determined by immunohistochemistry was observed in treated tumors. These data clearly establish the efficacy of liposomal curcumin in reducing human pancreatic cancer growth in the examined model. The therapeutic curcumin-based effects, with no limiting side-effects, suggest that liposomal curcumin may be beneficial in patients with pancreatic cancer.

  11. Pentoxifylline inhibits hypoxia-induced upregulation of tumor cell tissue factor and vascular endothelial growth factor.

    PubMed

    Amirkhosravi, A; Meyer, T; Warnes, G; Amaya, M; Malik, Z; Biggerstaff, J P; Siddiqui, F A; Sherman, P; Francis, J L

    1998-10-01

    Tissue factor (TF), the membrane glycoprotein that initiates blood coagulation, is constitutively expressed by many tumor cells and is implicated in peri-tumor fibrin deposition and hypercoagulability in cancer. Upregulation of tumor TF correlates with enhanced metastatic potential. Furthermore, TF has been colocalized with VEGF in breast cancer, specially at sites of early angiogenesis. There are no data on the effect of hypoxia on tumor cell TF expression. Since hypoxia is known to stimulate VEGF production, we studied whether this also induces tumor cell TF expression. Confluent monolayers of A375 melanoma, MCF-7 breast carcinoma and A549 lung carcinoma were cultured in either 95% air, 5% CO2 (normoxic) or 95% N2, 5% CO2 (hypoxic; 25-30 mmHg) for 24 h. Procoagulant activity (PCA) was measured by amidolytic and clotting assays, surface TF antigen by flow cytometry, early apoptosis by annexin V binding and VEGF levels in culture supernatants by ELISA. Hypoxia significantly increased tumor cell PCA in all three cell lines tested and TF antigen on A375 cells was increased four-fold (P <0.05). Pentoxifylline (PTX), a methylxanthine derivative, significantly inhibited the hypoxia-induced increase in PCA as well as VEGF release in all three cell lines tested. In A375 cells, PTX significantly inhibited TF antigen expression by both normoxic and hypoxic cells. Hypoxia induced a slight (5%) but not significant, increase in early apoptosis. Intravenous injection of hypoxic A375 cells into nude rats produced more pronounced thrombocytopenia (n = 5, P <0.01) and more lung metastases (n = 3, P <0.05) compared to normoxic cells. We conclude that hypoxia increases TF expression by malignant cells which enhances tumor cell-platelet binding and hematogenous metastasis. Hypoxia-induced upregulation of TF appears to parallel that of VEGF, although the mechanism remains unclear.

  12. Sensitizing acute myeloid leukemia cells to induced differentiation by inhibiting the RIP1/RIP3 pathway.

    PubMed

    Xin, J; You, D; Breslin, P; Li, J; Zhang, J; Wei, W; Cannova, J; Volk, A; Gutierrez, R; Xiao, Y; Ni, A; Ng, G; Schmidt, R; Xia, Z; Pan, J; Chen, H; Patel, M M; Kuo, P C; Nand, S; Kini, A R; Zhang, J; Chen, J; Zhu, J; Zhang, J

    2017-05-01

    Tumor necrosis factor-α (TNF-α)-induced RIP1/RIP3 (receptor-interacting protein kinase 1/receptor-interacting protein kinase 3)-mediated necroptosis has been proposed as an alternative strategy for treating apoptosis-resistant leukemia. However, we found that most acute myeloid leukemia (AML) cells, especially M4 and M5 subtypes, produce TNF and show basal level activation of RIP1/RIP3/MLKL signaling, yet do not undergo necroptosis. TNF, through RIP1/RIP3 signaling, prevents degradation of SOCS1, a key negative regulator of interferon-γ (IFN-γ) signaling. Using both pharmacologic and genetic assays, we show here that inactivation of RIP1/RIP3 resulted in reduction of SOCS1 protein levels and partial differentiation of AML cells. AML cells with inactivated RIP1/RIP3 signaling show increased sensitivity to IFN-γ-induced differentiation. RIP1/RIP3 inactivation combined with IFN-γ treatment significantly attenuated the clonogenic capacity of both primary AML cells and AML cell lines. This combination treatment also compromised the leukemogenic ability of murine AML cells in vivo. Our studies suggest that inhibition of RIP1/RIP3-mediated necroptotic signaling might be a novel strategy for the treatment of AML when combined with other differentiation inducers.

  13. Sensitizing Acute Myeloid Leukemia Cells to Induced Differentiation by Inhibiting the RIP1/RIP3 Pathway

    PubMed Central

    Xin, Junping; You, Dewen; Breslin, Peter; Li, Jing; Zhang, Jun; Wei, Wei; Cannova, Joseph; Volk, Andrew; Gutierrez, Rafael; Xiao, Yechen; Ni, Allen; Ng, Grace; Schmidt, Rachel; Xia, Zhixin; Pan, Jerry; Chen, Haiyan; Patel, Malini M.; Kuo, Paul C; Nand, Sucha; Kini, Ameet R; Zhang, Jianke; Chen, Jianjun; Zhu, Jiang; Zhang, Jiwang

    2017-01-01

    Tumor necrosis factor-α (TNF)-induced RIP1/RIP3-mediated necroptosis has been proposed to be an alternative strategy for treating apoptosis-resistant leukemia. However, we found that most acute myeloid leukemia (AML) cells, especially M4 and M5 subtypes, produce TNF and show basal level activation of RIP1/RIP3/MLKL signaling, yet do not undergo necroptosis. TNF, through RIP1/RIP3 signaling, prevents degradation of SOCS1, a key negative regulator of interferon-γ (IFN-γ) signaling. Using both pharmacologic and genetic assays, we show here that inactivation of RIP1/RIP3 resulted in reduction of SOCS1 protein levels and partial differentiation of AML cells. AML cells with inactivated RIP1/RIP3 signaling show increased sensitivity to IFN-γ-induced differentiation. RIP1/RIP3 inactivation combined with IFN-γ treatment significantly attenuated the clonogenic capacity of both primary AML cells and AML cell lines. This combination treatment also compromised the leukemogenic ability of murine AML cells in vivo. Our studies suggest that inhibition of RIP1/RIP3-mediated necroptotic signaling might be a novel strategy for the treatment of AML when combined with other differentiation inducers. PMID:27748372

  14. Pharmacological inhibition of Bcl-xL sensitizes osteosarcoma to doxorubicin

    PubMed Central

    Baranski, Zuzanna; de Jong, Yvonne; Ilkova, Trayana; Peterse, Elisabeth F.P.; Cleton-Jansen, Anne-Marie; van de Water, Bob; Hogendoorn, Pancras C.W.; Bovée, Judith V.M.G.; Danen, Erik H.J.

    2015-01-01

    High-grade conventional osteosarcoma is the most common primary bone tumor. Prognosis for osteosarcoma patients is poor and resistance to chemotherapy is common. We performed an siRNA screen targeting members of the Bcl-2 family in human osteosarcoma cell lines to identify critical regulators of osteosarcoma cell survival. Silencing the anti-apoptotic family member Bcl-xL but also the pro-apoptotic member Bak using a SMARTpool of siRNAs as well as 4/4 individual siRNAs caused loss of viability. Loss of Bak impaired cell cycle progression and triggered autophagy. Instead, silencing Bcl-xL induced apoptotic cell death. Bcl-xL was expressed in clinical osteosarcoma samples but mRNA or protein levels did not significantly correlate with therapy response or survival. Nevertheless, pharmacological inhibition of a range of Bcl-2 family members showed that inhibitors targeting Bcl-xL synergistically enhanced the response to the chemotherapeutic agent, doxorubicin. Indeed, in osteosarcoma cells strongly expressing Bcl-xL, the Bcl-xL-selective BH3 mimetic, WEHI-539 potently enhanced apoptosis in the presence of low doses of doxorubicin. Our results identify Bcl-xL as a candidate drug target for sensitization to chemotherapy in patients with osteosarcoma. PMID:26416351

  15. Targeting Notch, a key pathway for ovarian cancer stem cells, sensitizes tumors to platinum therapy.

    PubMed

    McAuliffe, Shannon M; Morgan, Stefanie L; Wyant, Gregory A; Tran, Lieu T; Muto, Katherine W; Chen, Yu Sarah; Chin, Kenneth T; Partridge, Justin C; Poole, Barish B; Cheng, Kuang-Hung; Daggett, John; Cullen, Kristen; Kantoff, Emily; Hasselbatt, Kathleen; Berkowitz, Julia; Muto, Michael G; Berkowitz, Ross S; Aster, Jon C; Matulonis, Ursula A; Dinulescu, Daniela M

    2012-10-23

    Chemoresistance to platinum therapy is a major obstacle that needs to be overcome in the treatment of ovarian cancer patients. The high rates and patterns of therapeutic failure seen in patients are consistent with a steady accumulation of drug-resistant cancer stem cells (CSCs). This study demonstrates that the Notch signaling pathway and Notch3 in particular are critical for the regulation of CSCs and tumor resistance to platinum. We show that Notch3 overexpression in tumor cells results in expansion of CSCs and increased platinum chemoresistance. In contrast, γ-secretase inhibitor (GSI), a Notch pathway inhibitor, depletes CSCs and increases tumor sensitivity to platinum. Similarly, a Notch3 siRNA knockdown increases the response to platinum therapy, further demonstrating that modulation of tumor chemosensitivity by GSI is Notch specific. Most importantly, the cisplatin/GSI combination is the only treatment that effectively eliminates both CSCs and the bulk of tumor cells, indicating that a dual combination targeting both populations is needed for tumor eradication. In addition, we found that the cisplatin/GSI combination therapy has a synergistic cytotoxic effect in Notch-dependent tumor cells by enhancing the DNA-damage response, G(2)/M cell-cycle arrest, and apoptosis. Based on these results, we conclude that targeting the Notch pathway could significantly increase tumor sensitivity to platinum therapy. Our study suggests important clinical applications for targeting Notch as part of novel treatment strategies upon diagnosis of ovarian cancer and at recurrence. Both platinum-resistant and platinum-sensitive relapses may benefit from such an approach as clinical data suggest that all relapses after platinum therapy are increasingly platinum resistant.

  16. Avastin® in combination with gemcitabine and cisplatin significantly inhibits tumor angiogenesis and increases the survival rate of human A549 tumor-bearing mice

    PubMed Central

    LIU, YING; XIA, XIZHENG; ZHOU, MINGKAI; LIU, XIAOJUN

    2015-01-01

    The aim of this study was to investigate the effect of Avastin® in combination with gemcitabine and cisplatin (GP) on the tumor growth of A549 tumor-bearing mice and the potential anti-tumor mechanism. A total of 30 human A549 tumor-bearing nude mice were randomly divided into the Avastin, chemotherapy and combined treatment groups for treatment with an intraperitoneal injection of Avastin (5 mg/kg) (Avastin group); an intraperitoneal injection of gemcitabine (4 mg/kg) and cisplatin (4 mg/kg) (chemotherapy group); or intraperitoneal injections of Avastin and GP (combined treatment group). The mice were observed for 30 days and the tumor growth, survival and body weight of the mice in the three groups were analyzed. The protein level of vascular endothelial growth factor (VEGF) in the tumor tissues was analyzed by ELISA. The vascular density and structural changes of the tumor were analyzed using immunohistochemistry. Compared with the Avastin and chemotherapy groups, the tumor growth of mice in the combined treatment group was significantly inhibited, and the survival rate of the mice was increased significantly. No difference in body weight was observed among the three groups of mice (P>0.05). The levels of VEGF in the combined treatment group tumor tissues were significantly reduced compared with those in the chemotherapy group tumor tissues (P<0.05). Furthermore, the vessel density of the tumor tissue in the combined treatment group was significantly reduced compared with that in the chemotherapy group (P<0.05), and the number of normal vessels in the combined treatment group tumors was significantly higher than that in the chemotherapy group tumors after 7 days of treatment (P<0.05). In conclusion, Avastin can significantly decrease the level of VEGF in tumor tissue, inhibit tumor angiogenesis and promote the normalization of tumor vascular structure, which may explain the enhanced efficacy of Avastin in combination with chemotherapy. PMID:26136956

  17. Antibody against CD44s Inhibits Pancreatic Tumor Initiation and Post-Radiation Recurrence in Mice

    PubMed Central

    Li, Ling; Hao, Xinbao; Qin, Jun; Tang, Wenhua; He, Fengtian; Smith, Amber; Zhang, Min; Simeone, Diane M.; Qiao, Xiaotan T.; Chen, Zhi-Nan; Lawrence, Theodore S.; Xu, Liang

    2014-01-01

    Background & Aims CD44s is a surface marker of tumor-initiating cells (TICs); high tumor levels correlate with metastasis and recurrence, as well as poor outcomes of patients. Monoclonal antibodies against CD44s might eliminate TICs with minimal toxicity. This strategy is unclear for treatment of pancreatic cancer, and little is known about how anti-CD44s affect pancreatic cancer initiation or recurrence after radiotherapy. Methods 192 pairs of human pancreatic adenocarcinoma and adjacent non-tumor pancreatic tissues were collected from patients undergoing surgery. We measured CD44s levels in tissue samples and pancreatic cancer cell lines by immunohistochemistry, real-time PCR and immunoblot; levels were correlated with patient survival times. We studied the effects of anti-CD44s in mice with human pancreatic tumor xenografts, and used flow cytometry to determine effects on TICs. Changes in CD44s signaling were examined by real-time PCR, immunoblot, reporter assay, and in vitro tumorsphere formation assays. Results Levels of CD44s were significantly higher in pancreatic cancer than adjacent non-tumor tissues. Patients whose tumors expressed high levels of CD44s had a median survival of 10 months, compared to 43 months for those with low levels. Anti-CD44s reduced growth, metastasis, and post-radiation recurrence of pancreatic xenograft tumors in mice. The antibody reduced the number of TICs in cultured pancreatic cancer cells and in xenograft tumors, as well as their tumorigenicity. In cultured pancreatic cancer cell lines, anti-CD44s downregulated the stem cell self-renewal genes Nanog, Sox-2, and Rex-1 and inhibited STAT3-mediated cell proliferation and survival signaling. Conclusions The TIC marker CD44s is upregulated in human pancreatic tumors and associated with patient survival time. CD44s is required for initiation, growth, metastasis, and post-radiation recurrence of xenograft tumors in mice. Anti-CD44s eliminated bulk tumor cells as well as TICs from the

  18. Targeting Focal Adhesion Kinase and Resistance to mTOR Inhibition in Pancreatic Neuroendocrine Tumors

    PubMed Central

    François, Rony A.; Maeng, Kyungah; Nawab, Akbar; Kaye, Frederic J.; Hochwald, Steven N.; Zajac-Kaye, Maria

    2015-01-01

    Background: Focal adhesion kinase (FAK) mediates survival of normal pancreatic islets through activation of AKT. Upon malignant transformation of islet cells into pancreatic neuroendocrine tumors (PanNETs), AKT is frequently overexpressed and mutations in the AKT/mTOR pathway are detected. Because mTOR inhibitors rarely induce PanNET tumor regression, partly because of feedback activation of AKT, novel combination strategies are needed to target FAK/AKT/mTOR signaling. Methods: We characterized the activation of FAK in PanNETs using immunohistochemistry and Western blot analysis and tested the FAK inhibitor PF-04554878 in human PanNET cells in vitro and in vivo (at least three mice per group). In addition, we evaluated the effect of combined FAK and mTOR inhibition on PanNET viability and apoptosis. All statistical tests were two-sided. Results: We found that FAK is overexpressed and hyperphosphorylated in human PanNETs and that PF-04554878 strongly inhibited FAK (Tyr397) autophosphorylation in a dose-dependent manner. We found that PF-04554878 inhibited cell proliferation and clonogenicity and induced apoptosis in PanNET cells. Moreover, oral administration of PF-04554878 statistically significantly reduced tumor growth in a patient-derived xenograft model of PanNET (P = .02) and in a human PanNET xenograft model of peritoneal carcinomatosis (P = .03). Importantly, PF-04554878 synergized with the mTOR inhibitor everolimus by preventing feedback AKT activation. Conclusions: We demonstrate for the first time that FAK is overexpressed in PanNETs and that inhibition of FAK activity induces apoptosis and inhibits PanNET proliferation. We found that the novel FAK inhibitor PF-04554878 synergizes with everolimus, a US Food and Drug Administration–approved agent for PanNETs. Our findings warrant the clinical investigation of combined FAK and mTOR inhibition in PanNETs. PMID:25971297

  19. Midazolam Induces Cellular Apoptosis in Human Cancer Cells and Inhibits Tumor Growth in Xenograft Mice

    PubMed Central

    Mishra, Siddhartha Kumar; Kang, Ju-Hee; Lee, Chang Woo; Oh, Seung Hyun; Ryu, Jun Sun; Bae, Yun Soo; Kim, Hwan Mook

    2013-01-01

    Midazolam is a widely used anesthetic of the benzodiazepine class that has shown cytotoxicity and apoptosis-inducing activity in neuronal cells and lymphocytes. This study aims to evaluate the effect of midazolam on growth of K562 human leukemia cells and HT29 colon cancer cells. The in vivo effect of midazolam was investigated in BALB/c-nu mice bearing K562 and HT29 cells human tumor xenografts. The results show that midazolam decreased the viability of K562 and HT29 cells by inducing apoptosis and S phase cell-cycle arrest in a concentration-dependent manner. Midazolam activated caspase-9, capspase-3 and PARP indicating induction of the mitochondrial intrinsic pathway of apoptosis. Midazolam lowered mitochondrial membrane potential and increased apoptotic DNA fragmentation. Midazolam showed reactive oxygen species (ROS) scavenging activity through inhibition of NADPH oxidase 2 (Nox2) enzyme activity in K562 cells. Midazolam caused inhibition of pERK1/2 signaling which led to inhibition of the anti-apoptotic proteins Bcl-XL and XIAP and phosphorylation activation of the pro-apoptotic protein Bid. Midazolam inhibited growth of HT29 tumors in xenograft mice. Collectively our results demonstrate that midazolam caused growth inhibition of cancer cells via activation of the mitochondrial intrinsic pathway of apoptosis and inhibited HT29 tumor growth in xenograft mice. The mechanism underlying these effects of midazolam might be suppression of ROS production leading to modulation of apoptosis and growth regulatory proteins. These findings present possible clinical implications of midazolam as an anesthetic to relieve pain during in vivo anticancer drug delivery and to enhance anticancer efficacy through its ROS-scavenging and pro-apoptotic properties. PMID:24008365

  20. Tumor Therapeutics Work as Stress Inducers to Enhance Tumor Sensitivity to Natural Killer (NK) Cell Cytolysis by Up-regulating NKp30 Ligand B7-H6.

    PubMed

    Cao, Guoshuai; Wang, Jian; Zheng, Xiaodong; Wei, Haiming; Tian, Zhigang; Sun, Rui

    2015-12-11

    Immune cells are believed to participate in initiating anti-tumor effects during regular tumor therapy such as chemotherapy, radiation, hyperthermia, and cytokine injection. One of the mechanisms underlying this process is the expression of so-called stress-inducible immunostimulating ligands. Although the activating receptor NKG2D has been proven to play roles in tumor therapy through targeting its ligands, the role of NKp30, another key activating receptor, is seldom addressed. In this study, we found that the NKp30 ligand B7-H6 was widely expressed in tumor cells and closely correlated to their susceptibility to NK cell lysis. Further studies showed that treatment of tumor cells with almost all standard tumor therapeutics, including chemotherapy (cisplatin, 5-fluorouracil), radiation therapy, non-lethal heat shock, and cytokine therapy (TNF-α), could up-regulate the expression of B7-H6 in tumor cells and enhance tumor sensitivity to NK cell cytolysis. B7-H6 shRNA treatment effectively dampened sensitization of tumor cells to NK-mediated lysis. Our study not only reveals the possibility that tumor therapeutics work as stress inducers to enhance tumor sensitivity to NK cell cytolysis but also suggests that B7-H6 could be a potential target for tumor therapy in the future.

  1. Monodispersed calcium carbonate nanoparticles modulate local pH and inhibit tumor growth in vivo

    NASA Astrophysics Data System (ADS)

    Som, Avik; Raliya, Ramesh; Tian, Limei; Akers, Walter; Ippolito, Joseph E.; Singamaneni, Srikanth; Biswas, Pratim; Achilefu, Samuel

    2016-06-01

    The acidic extracellular environment of tumors potentiates their aggressiveness and metastasis, but few methods exist to selectively modulate the extracellular pH (pHe) environment of tumors. Transient flushing of biological systems with alkaline fluids or proton pump inhibitors is impractical and nonselective. Here we report a nanoparticles-based strategy to intentionally modulate the pHe in tumors. Biochemical simulations indicate that the dissolution of calcium carbonate nanoparticles (nano-CaCO3) in vivo increases pH asymptotically to 7.4. We developed two independent facile methods to synthesize monodisperse non-doped vaterite nano-CaCO3 with distinct size range between 20 and 300 nm. Using murine models of cancer, we demonstrate that the selective accumulation of nano-CaCO3 in tumors increases tumor pH over time. The associated induction of tumor growth stasis is putatively interpreted as a pHe increase. This study establishes an approach to prepare nano-CaCO3 over a wide particle size range, a formulation that stabilizes the nanomaterials in aqueous solutions, and a pH-sensitive nano-platform capable of modulating the acidic environment of cancer for potential therapeutic benefits.The acidic extracellular environment of tumors potentiates their aggressiveness and metastasis, but few methods exist to selectively modulate the extracellular pH (pHe) environment of tumors. Transient flushing of biological systems with alkaline fluids or proton pump inhibitors is impractical and nonselective. Here we report a nanoparticles-based strategy to intentionally modulate the pHe in tumors. Biochemical simulations indicate that the dissolution of calcium carbonate nanoparticles (nano-CaCO3) in vivo increases pH asymptotically to 7.4. We developed two independent facile methods to synthesize monodisperse non-doped vaterite nano-CaCO3 with distinct size range between 20 and 300 nm. Using murine models of cancer, we demonstrate that the selective accumulation of nano-CaCO3

  2. Inhibition of PDE5 by sulindac sulfide selectively induces apoptosis and attenuates oncogenic Wnt/β-catenin mediated transcription in human breast tumor cells

    PubMed Central

    Tinsley, Heather N.; Gary, Bernard D.; Keeton, Adam B.; Lu, Wenyan; Li, Yonghe; Piazza, Gary A.

    2011-01-01

    Nonsteroidal anti-inflammatory drugs (NSAIDs) such as sulindac sulfide (SS) display promising antineoplastic properties, but toxicities resulting from cyclooxygenase (COX) inhibition limit their clinical use. While COX inhibition is responsible for the anti-inflammatory activity of SS, recent studies suggest that phosphodiesterase (PDE) 5 inhibition and activation of cGMP signaling are closely associated with its ability to induce apoptosis of tumor cells. However, the underlying mechanisms responsible for apoptosis induction, factors that influence sensitivity of tumor cells to SS, and the importance of PDE5 for breast tumor cell growth have not been established. Here we show that SS can induce apoptosis of breast tumor cells, which predominantly rely on PDE5 for cGMP hydrolysis, but not normal mammary epithelial cells, which rely on PDE isozymes other than PDE5 for cGMP hydrolysis. Inhibition of PDE5 and activation of PKG by SS was associated with increased β-catenin phosphorylation, decreased β-catenin mRNA and protein levels, reduced β-catenin nuclear localization, decreased Tcf/Lef promoter activity, and decreased expression of Wnt/β-catenin regulated proteins. Suppression of PDE5 with siRNA or known PDE5 inhibitors was sufficient to selectively induce apoptosis and attenuate β-catenin mediated transcription in breast tumor cells with minimal effects on normal mammary epithelial cells. These findings provide evidence that SS induces apoptosis of breast tumor cells through a mechanism involving inhibition of PDE5 and attenuation of oncogenic Wnt/β-catenin mediated transcription. We conclude that PDE5 represents a novel molecular target for the discovery of safer and more efficacious drugs for breast cancer chemoprevention. PMID:21505183

  3. Inhibition of PDE5 by sulindac sulfide selectively induces apoptosis and attenuates oncogenic Wnt/β-catenin-mediated transcription in human breast tumor cells.

    PubMed

    Tinsley, Heather N; Gary, Bernard D; Keeton, Adam B; Lu, Wenyan; Li, Yonghe; Piazza, Gary A

    2011-08-01

    Nonsteroidal anti-inflammatory drugs (NSAID) such as sulindac sulfide (SS) display promising antineoplastic properties, but toxicities resulting from COX inhibition limit their clinical use. Although COX inhibition is responsible for the anti-inflammatory activity of SS, recent studies suggest that phosphodiesterase (PDE) 5 inhibition and activation of cyclic guanosine monophosphate (cGMP) signaling are closely associated with its ability to induce apoptosis of tumor cells. However, the underlying mechanisms responsible for apoptosis induction, factors that influence sensitivity of tumor cells to SS, and the importance of PDE5 for breast tumor cell growth have not been established. Here we show that SS can induce apoptosis of breast tumor cells, which predominantly rely on PDE5 for cGMP hydrolysis but not normal mammary epithelial cells, which rely on PDE isozymes other than PDE5 for cGMP hydrolysis. Inhibition of PDE5 and activation of protein kinase G (PKG) by SS was associated with increased β-catenin phosphorylation, decreased β-catenin mRNA and protein levels, reduced β-catenin nuclear localization, decreased T-cell factor/lymphoid enhancer factor (Tcf/Lef) promoter activity, and decreased expression of Wnt/β-catenin-regulated proteins. Suppression of PDE5 with siRNA or known PDE5 inhibitors was sufficient to selectively induce apoptosis and attenuate β-catenin-mediated transcription in breast tumor cells with minimal effects on normal mammary epithelial cells. These findings provide evidence that SS induces apoptosis of breast tumor cells through a mechanism involving inhibition of PDE5 and attenuation of oncogenic Wnt/β-catenin-mediated transcription. We conclude that PDE5 represents a novel molecular target for the discovery of safer and more efficacious drugs for breast cancer chemoprevention.

  4. [Possible relation between viruses and oromaxillofacial tumors. V. Demonstration of hemagglutination-inhibiting anti-BK virus antibodies in patients with tumors of the parotid gland].

    PubMed

    Stoian, M; Zaharia, O; Suru, M; Constantinescu, E; Goldstein, I; Nastac, E

    1987-01-01

    Anti-BK-virus hemagglutination inhibiting antibodies were revealed in 81.8% of the patients with parotid gland tumors. Results of the investigations conducted on oromaxillofacial tumors including the parotid gland ones are discussed from the point of view of the presence of viral antigens (herpes-, SV40 and BK-viruses) and of specific antibodies. Possible implication of the papova viruses in the etiopathogenesis of the parotid gland tumors in humans are also discussed.

  5. CXCR3 as a molecular target in breast cancer metastasis: inhibition of tumor cell migration and promotion of host anti-tumor immunity.

    PubMed

    Zhu, Guiquan; Yan, H Hannah; Pang, Yanli; Jian, Jiang; Achyut, Bhagelu R; Liang, Xinhua; Weiss, Jonathan M; Wiltrout, Robert H; Hollander, M Christine; Yang, Li

    2015-12-22

    Chemokines and chemokine receptors have critical roles in cancer metastasis and have emerged as one of the targeting options in cancer therapy. However, the treatment efficacy on both tumor and host compartments needs to be carefully evaluated. Here we report that targeting CXCR3 decreased tumor cell migration and at the same time improved host anti-tumor immunity. We observed an increased expression of CXCR3 in metastatic tumor cells compared to those from non-metastatic tumor cells. Knockdown (KD) of CXCR3 in metastatic tumor cells suppressed tumor cell migration and metastasis. Importantly, CXCR3 expression in clinical breast cancer samples correlated with progression and metastasis. For the host compartment, deletion of CXCR3 in all host cells in 4T1 mammary tumor model significantly decreased metastasis. The underlying mechanisms involve a decreased expression of IL-4, IL-10, iNOs, and Arg-1 in myeloid cells and an increased T cell response. IFN-γ neutralization diminished the metastasis inhibition in the CXCR3 knockout (KO) mice bearing 4T1 tumors, suggesting a critical role of host CXCR3 in immune suppression. Consistently, targeting CXCR3 using a small molecular inhibitor (AMG487) significantly suppressed metastasis and improved host anti-tumor immunity. Our findings demonstrate that targeting CXCR3 is effective in both tumor and host compartments, and suggest that CXCR3 inhibition is likely to avoid adverse effects on host cells.

  6. Clinically used antirheumatic agent auranofin is a proteasomal deubiquitinase inhibitor and inhibits tumor growth

    PubMed Central

    Song, Wenbin; Lu, Xiaoyu; Lan, Xiaoying; Chen, Xin; Yi, Songgang; Xu, Li; Jiang, Lili; Zhao, Canguo; Dong, Xiaoxian; Zhou, Ping; Li, Shujue; Wang, Shunqing; Shi, Xianping; Dou, Ping Q.; Wang, Xuejun; Liu, Jinbao