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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. Hypoxic Signaling and the Cellular Redox Tumor Environment Determine Sensitivity to MTH1 Inhibition.

    PubMed

    Bräutigam, Lars; Pudelko, Linda; Jemth, Ann-Sofie; Gad, Helge; Narwal, Mohit; Gustafsson, Robert; Karsten, Stella; Carreras Puigvert, Jordi; Homan, Evert; Berndt, Carsten; Berglund, Ulrika Warpman; Stenmark, Pål; Helleday, Thomas

    2016-04-15

    Cancer cells are commonly in a state of redox imbalance that drives their growth and survival. To compensate for oxidative stress induced by the tumor redox environment, cancer cells upregulate specific nononcogenic addiction enzymes, such as MTH1 (NUDT1), which detoxifies oxidized nucleotides. Here, we show that increasing oxidative stress in nonmalignant cells induced their sensitization to the effects of MTH1 inhibition, whereas decreasing oxidative pressure in cancer cells protected against inhibition. Furthermore, we purified zebrafish MTH1 and solved the crystal structure of MTH1 bound to its inhibitor, highlighting the zebrafish as a relevant tool to study MTH1 biology. Delivery of 8-oxo-dGTP and 2-OH-dATP to zebrafish embryos was highly toxic in the absence of MTH1 activity. Moreover, chemically or genetically mimicking activated hypoxia signaling in zebrafish revealed that pathologic upregulation of the HIF1α response, often observed in cancer and linked to poor prognosis, sensitized embryos to MTH1 inhibition. Using a transgenic zebrafish line, in which the cellular redox status can be monitored in vivo, we detected an increase in oxidative pressure upon activation of hypoxic signaling. Pretreatment with the antioxidant N-acetyl-L-cysteine protected embryos with activated hypoxia signaling against MTH1 inhibition, suggesting that the aberrant redox environment likely causes sensitization. In summary, MTH1 inhibition may offer a general approach to treat cancers characterized by deregulated hypoxia signaling or redox imbalance. Cancer Res; 76(8); 2366-75. ©2016 AACR. PMID:26862114

  3. 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. PMID:23934106

  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. Sensitivity of human granulosa cell tumor cells to epidermal growth factor receptor inhibition.

    PubMed

    Andersson, Noora; Anttonen, Mikko; Färkkilä, Anniina; Pihlajoki, Marjut; Bützow, Ralf; Unkila-Kallio, Leila; Heikinheimo, Markku

    2014-04-01

    Epidermal growth factor receptor (EGFR) is implicated in the progression of many human cancers, but its significance in ovarian granulosa cell tumor (GCT) pathobiology remains poorly understood. We assessed the EGFR gene copy number, surveyed the mRNA and protein expression patterns of EGFR in 90 adult GCTs, and assessed the in vitro sensitivity of GCT cells to EGFR inhibition. Low-level amplification of EGFR gene was observed in five GCTs and high-level amplification in one sample. EGFR mRNA was robustly expressed in GCTs. Most tumors expressed both unphosphorylated and phosphorylated EGFR protein, but the protein expression did not correlate with clinical parameters, including the risk of recurrence. Small-molecule EGFR inhibitors reduced the EGF-induced activation of EGFR and its downstream signaling molecules at nanomolar doses, but cell viability was reduced, and caspase-3/7 was activated in GCT cells only at micromolar doses. Based on the present results, EGFR is active and abundantly expressed in the majority of GCTs, but probably has only minor contribution to GCT cell growth. Given the high doses of EGFR inhibitors required to reduce GCT cell viability in vitro, they are not likely to be effective for GCT treatment as single agents; they should rather be tested as part of combination therapies for these malignancies. PMID:24463098

  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

    2016-01-01

    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. PMID:27378792

  9. 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. PMID:25388513

  10. MDM2 antagonist nutlin-3a sensitizes tumors to V-ATPase inhibition.

    PubMed

    Schneider, Lina S; Ulrich, Melanie; Lehr, Thorsten; Menche, Dirk; Müller, Rolf; von Schwarzenberg, Karin

    2016-08-01

    Treating cancer is one of the big challenges of this century and it has become evident that single chemotherapeutic treatment is rarely effective. As tumors often carry multiple mutations using combination therapy which addresses different targets seems therefore more beneficial. One of the most frequently mutated genes in tumors is the tumor suppressor p53. Significant work has been put in the development of p53 activators, which are now in clinical studies against diverse cancers. Recently, we could show that inhibition of V-ATPase, a multisubunit proton pump, by archazolid induces p53 protein levels in cancer cells. In this study, we provide evidence that the combination of archazolid with the p53 activator nutlin-3a is synergistically inducing cell death in different p53 wild type tumor cell lines. Mechanistically, this effect could presumably be attributed to reduction of glycolysis as TIGAR mRNA levels were increased and glucose uptake and Glut1 protein levels were reduced. In addition, combination treatment highly activated pro-apoptotic pathways including IGFBP3 and Bax inducing caspase-9 and PARP cleavage. Remarkably, combination of archazolid and nutlin-3a was more efficient in reducing tumor growth compared to single dose treatment in a U87MG mouse model in vivo. Hence, our findings suggest the combination of archazolid and nutlin-3a as a highly promising strategy for the treatment of p53 wild type tumors. PMID:27157929

  11. Targeting BRCA1 localization to augment breast tumor sensitivity to poly(ADP-ribose) polymerase inhibition

    PubMed Central

    Yang, Eddy S.; Nowsheen, Somaira; Rahman, Mohammad A.; Cook, Rebecca S.; Xia, Fen

    2013-01-01

    Poly(ADP-ribose) polymerase inhibitors have gained recent attention due to their highly selective killing of BRCA1/2 mutated and DNA double strand break (DSB) repair deficient tumors. Unfortunately, the majority of sporadic breast cancers carry wild-type BRCA1/2 and are proficient in DSB repair. We and others have shown that BRCA1 is a nuclear/cytoplasm shuttling protein which is transiently exported from the nucleus to the cytosol upon various stimuli. Thus, we hypothesized that depletion of nuclear BRCA1 would compromise DSB repair and subsequently render sporadic tumors susceptible to PARP inhibition. Indeed, in human sporadic breast cancer cells with functional BRCA1 and proficient DSB repair, a transient nuclear depletion of BRCA1 and subsequent HR repair deficit was induced with either truncated BRCA1 or irradiation. This rendered these human sporadic breast cancer cells susceptible to PARP inhibition. These observations were confirmed genetically using mislocated BRCA1 mutants as well as in vivo in mice bearing breast tumor xenografts. These data support the potential strategy of targeting BRCA1 location to convert BRCA1-proficient sporadic tumors to be susceptible to the synthetic lethal combination with PARP inhibitors. PMID:22962264

  12. Sensitivity to cdk1-inhibition is modulated by p53 status in preclinical models of embryonal tumors

    PubMed Central

    Schwermer, Melanie; Lee, Sangkyun; Köster, Johannes; van Maerken, Tom; Stephan, Harald; Eggert, Angelika; Morik, Katharina; Schulte, Johannes H.; Schramm, Alexander

    2015-01-01

    Dysregulation of the cell cycle and cyclin-dependent kinases (cdks) is a hallmark of cancer cells. Intervention with cdk function is currently evaluated as a therapeutic option in many cancer types including neuroblastoma (NB), a common solid tumor of childhood. Re-analyses of mRNA profiling data from primary NB revealed that high level mRNA expression of both cdk1 and its corresponding cyclin, CCNB1, were significantly associated with worse patient outcome independent of MYCN amplification, a strong indicator of adverse NB prognosis. Cdk1 as well as CCNB1 expression were readily detectable in all embryonal tumor cell lines investigated. Pharmacological inhibition or siRNA-mediated knockdown of cdk1/CCNB1 induced proliferation arrest independent of MYCN status in NB cells. Sensitivity to cdk1 inhibition was modulated by TP53, which was demonstrated using isogenic cells with wild-type TP53 expressing either dominant-negative p53 or a short hairpin RNA directed against TP53. Apoptosis induced by cdk1 inhibition was dependent on caspase activation and was concomitant with upregulation of transcriptional targets of TP53. Our results confirm an essential role for the cdk1/CCNB1 complex in tumor cell survival. As relapsing embryonal tumors often present with p53 pathway alterations, these findings have potential implications for therapy approaches targeting cdks. PMID:26029996

  13. 3'-deoxy-3'-[18F]fluorothymidine positron emission tomography is a sensitive method for imaging the response of BRAF-dependent tumors to MEK inhibition.

    PubMed

    Solit, David B; Santos, Elmer; Pratilas, Christine A; Lobo, Jose; Moroz, Maxim; Cai, Shangde; Blasberg, Ronald; Sebolt-Leopold, Judith; Larson, Steven; Rosen, Neal

    2007-12-01

    Activating mutations of BRAF occur in approximately 7% of all human tumors and in the majority of melanomas. These tumors are very sensitive to pharmacologic inhibition of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK), which causes loss of D-cyclin expression, hypophosphorylation of Rb, and G(1) arrest. Growth arrest is followed by differentiation or senescence and, in a subset of BRAF mutant tumors, by apoptosis. The former effects result in so-called "stable disease" and, in patients with cancer, can be difficult to distinguish from indolent tumor growth. The profound G(1) arrest induced by MEK inhibition in BRAF mutant tumors is associated with a marked decline in thymidine uptake and is therefore potentially detectable in vivo by noninvasive 3'-deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT) positron emission tomography (PET) imaging. In SKMEL-28 tumor xenografts, MEK inhibition completely inhibited tumor growth and induced differentiation with only modest tumor regression. MEK inhibition also resulted in a rapid decline in the [(18)F]FLT signal in V600E BRAF mutant SKMEL-28 xenografts but not in BRAF wild-type BT-474 xenografts. The data suggest that [(18)F]FLT PET can effectively image induction of G(1) arrest by MEK inhibitors in mutant BRAF tumors and may be a useful noninvasive method for assessing the early biological response to this class of drugs. PMID:18056475

  14. 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

  15. 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.

  16. 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.

  17. Inhibition of multiple vascular endothelial growth factor receptors (VEGFR) blocks lymph node metastases but inhibition of VEGFR-2 is sufficient to sensitize tumor cells to platinum-based chemotherapeutics.

    PubMed

    Sini, Patrizia; Samarzija, Ivana; Baffert, Fabienne; Littlewood-Evans, Amanda; Schnell, Christian; Theuer, Andreas; Christian, Sven; Boos, Anja; Hess-Stumpp, Holger; Foekens, John A; Setyono-Han, Buddy; Wood, Jeanette; Hynes, Nancy E

    2008-03-01

    Vascular endothelial growth factor receptors (VEGFR) have important roles in cancer, affecting blood and lymphatic vessel functionality as well as tumor cells themselves. We compared the efficacy of a VEGFR tyrosine kinase inhibitor, PTK787/ZK222584 (PTK/ZK), which targets the three VEGFRs, with blocking antibodies directed against VEGFR-2 (DC101) or VEGF-A (Pab85618) in a metastatic melanoma model. Although all inhibitors exerted comparable effects on primary tumor growth, only PTK/ZK significantly reduced lymph node metastasis formation. A comparable decrease in lymphatic vessel density following blockade of VEGFR-2 (DC101) or the three VEGFRs (PTK/ZK) was observed in the metastases. However, the functionality of lymphatics surrounding the primary tumor was more significantly disrupted by PTK/ZK, indicating the importance of multiple VEGFRs in the metastatic process. The antimetastatic properties of PTK/ZK were confirmed in a breast carcinoma model. B16/BL6 tumor cells express VEGF ligands and their receptors. Blockade of a VEGFR-1 autocrine loop with PTK/ZK inhibited tumor cell migration. Furthermore, the tumor cells also showed enhanced sensitivity to platinum-based chemotherapy in combination with PTK/ZK, indicating that autocrine VEGFRs are promoting tumor cell migration and survival. In summary, our results suggest that, in addition to blocking angiogenesis, combined inhibition of the three VEGFRs may more efficiently target other aspects of tumor pathophysiology, including lymphatic vessel functionality, tumor cell dissemination, survival pathways, and response to chemotherapeutic compounds. PMID:18316624

  18. MicroRNA-137 inhibits tumor growth and sensitizes chemosensitivity to paclitaxel and cisplatin in lung cancer

    PubMed Central

    Ge, Xin; Jiang, Cheng-Fei; Shi, Zhu-Mei; Li, Dong-Mei; Liu, Wei-Tao; Yu, Xiaobo; Shu, Yong-Qian

    2016-01-01

    Chemotherapy resistance frequently drives tumour progression. However, the underlying molecular mechanisms are poorly characterized. In this study, we explored miR-137's role in the chemosensitivity of lung cancer. We found that the expression level of miR-137 is down-regulated in the human lung cancer tissues and the resistant cells strains: A549/paclitaxel(A549/PTX) and A549/cisplatin (A549/CDDP) when compared with lung cancer A549 cells. Moreover, we found that overe-expression of miR-137 inhibited cell proliferation, migration, cell survival and arrest the cell cycle in G1 phase in A549/PTX and A549/CDDP. Furthermore, Repression of miR-137 significantly promoted cell growth, migration, cell survival and cell cycle G1/S transition in A549 cells. We further demonstrated that the tumor suppressive role of miR-137 was mediated by negatively regulating Nuclear casein kinase and cyclin-dependent kinase substrate1(NUCKS1) protein expression. Importantly, miR-137 inhibits A549/PTX, A549/CDDP growth and angiogenesis in vivo. Our study is the first to identify the tumor suppressive role of over-expressed miR-137 in chemosensitivity. Identification of a novel miRNA-mediated pathway that regulates chemosensitivity in lung cancer will facilitate the development of novel therapeutic strategies in the future. PMID:26989074

  19. 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

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

    PubMed

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

    2016-08-11

    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

  1. Novel Piperazine-based Compounds Inhibit Microtubule Dynamics and Sensitize Colon Cancer Cells to Tumor Necrosis Factor-induced Apoptosis*

    PubMed Central

    Chopra, Avijeet; Anderson, Amy; Giardina, Charles

    2014-01-01

    We recently identified a series of mitotically acting piperazine-based compounds that potently increase the sensitivity of colon cancer cells to apoptotic ligands. Here we describe a structure-activity relationship study on this compound class and identify a highly active derivative ((4-(3-chlorophenyl)piperazin-1-yl)(2-ethoxyphenyl)methanone), referred to as AK301, the activity of which is governed by the positioning of functional groups on the phenyl and benzoyl rings. AK301 induced mitotic arrest in HT29 human colon cancer cells with an ED50 of ≈115 nm. Although AK301 inhibited growth of normal lung fibroblast cells, mitotic arrest was more pronounced in the colon cancer cells (50% versus 10%). Cells arrested by AK301 showed the formation of multiple microtubule organizing centers with Aurora kinase A and γ-tubulin. Employing in vitro and in vivo assays, tubulin polymerization was found to be slowed (but not abolished) by AK301. In silico molecular docking suggests that AK301 binds to the colchicine-binding domain on β-tubulin, but in a novel orientation. Cells arrested by AK301 expressed elevated levels of TNFR1 on their surface and more readily activated caspases-8, -9, and -3 in the presence of TNF. Relative to other microtubule destabilizers, AK301 was the most active TNF-sensitizing agent and also stimulated Fas- and TRAIL-induced apoptosis. In summary, we report a new class of mitosis-targeting agents that effectively sensitizes cancer cells to apoptotic ligands. These compounds should help illuminate the role of microtubules in regulating apoptotic ligand sensitivity and may ultimately be useful for developing agents that augment the anti-cancer activities of the immune response. PMID:24338023

  2. PLK1 is a critical determinant of tumor cell sensitivity to CPT11 and its inhibition enhances the drug antitumor efficacy in squamous cell carcinoma models sensitive and resistant to camptothecins.

    PubMed

    Zuco, Valentina; De Cesare, Michelandrea; Zaffaroni, Nadia; Lanzi, Cinzia; Cassinelli, Giuliana

    2015-04-20

    Intrinsic and acquired tumor drug resistance limits the therapeutic efficacy of camptothecins (CPTs). Downregulation of the mitotic kinase PLK1 was found associated with apoptosis induced by SN38 (CPT11 active metabolite). We investigated the role of PLK1 in the cell response to CPTs in squamous cell carcinoma (SCC) and pediatric sarcoma cell lines and explored the therapeutic potential of the combination of CPT11 and the PLK1 inhibitor BI2536 in CPT-sensitive and -resistant tumor models. Gain- and loss-of-function experiments established a direct role for PLK1 in counteracting SN38 antiproliferative and pro-apoptotic effects. The ability to activate an efficient G2/M cell cycle checkpoint allowing PLK1 ubiquitination and degradation was found associated with SN38-induced apoptosis in SCC cells. However, the synergistic interaction between SN38 and BI2536 enhanced apoptosis in cell lines both sensitive and resistant to SN38-induced apoptotic cell death. A well-tolerated CPT11/BI2536 cotreatment resulted in improved antitumor effect against SCC xenografts in mice compared to single agent treatments. The increased apoptosis induction was reflected in a high rate of complete responses and cures in mice harboring SCC, including tumors with intrinsic or acquired resistance to CPTs. PLK1 inhibition represents a promising strategy to improve the antitumor efficacy of CPT11-based regimens. PMID:25826089

  3. Recapitulation of Tumor Heterogeneity and Molecular Signatures in a 3D Brain Cancer Model with Decreased Sensitivity to Histone Deacetylase Inhibition

    PubMed Central

    Smith, Stuart J.; Wilson, Martin; Ward, Jennifer H.; Rahman, Cheryl V.; Peet, Andrew C.; Macarthur, Donald C.; Rose, Felicity R. A. J.; Grundy, Richard G.; Rahman, Ruman

    2012-01-01

    Introduction Physiologically relevant pre-clinical ex vivo models recapitulating CNS tumor micro-environmental complexity will aid development of biologically-targeted agents. We present comprehensive characterization of tumor aggregates generated using the 3D Rotary Cell Culture System (RCCS). Methods CNS cancer cell lines were grown in conventional 2D cultures and the RCCS and comparison with a cohort of 53 pediatric high grade gliomas conducted by genome wide gene expression and microRNA arrays, coupled with immunohistochemistry, ex vivo magnetic resonance spectroscopy and drug sensitivity evaluation using the histone deacetylase inhibitor, Vorinostat. Results Macroscopic RCCS aggregates recapitulated the heterogeneous morphology of brain tumors with a distinct proliferating rim, necrotic core and oxygen tension gradient. Gene expression and microRNA analyses revealed significant differences with 3D expression intermediate to 2D cultures and primary brain tumors. Metabolic profiling revealed differential profiles, with an increase in tumor specific metabolites in 3D. To evaluate the potential of the RCCS as a drug testing tool, we determined the efficacy of Vorinostat against aggregates of U87 and KNS42 glioblastoma cells. Both lines demonstrated markedly reduced sensitivity when assaying in 3D culture conditions compared to classical 2D drug screen approaches. Conclusions Our comprehensive characterization demonstrates that 3D RCCS culture of high grade brain tumor cells has profound effects on the genetic, epigenetic and metabolic profiles of cultured cells, with these cells residing as an intermediate phenotype between that of 2D cultures and primary tumors. There is a discrepancy between 2D culture and tumor molecular profiles, and RCCS partially re-capitulates tissue specific features, allowing drug testing in a more relevant ex vivo system. PMID:23272238

  4. Rapid decrease in tumor perfusion following VEGF blockade predicts long-term tumor growth inhibition in preclinical tumor models.

    PubMed

    Eichten, Alexandra; Adler, Alexander P; Cooper, Blerta; Griffith, Jennifer; Wei, Yi; Yancopoulos, George D; Lin, Hsin Chieh; Thurston, Gavin

    2013-04-01

    Vascular endothelial growth factor (VEGF) is a key upstream mediator of tumor angiogenesis, and blockade of VEGF can inhibit tumor angiogenesis and decrease tumor growth. However, not all tumors respond well to anti-VEGF therapy. Despite much effort, identification of early response biomarkers that correlate with long-term efficacy of anti-VEGF therapy has been difficult. These difficulties arise in part because the functional effects of VEGF inhibition on tumor vessels are still unclear. We therefore assessed rapid molecular, morphologic and functional vascular responses following treatment with aflibercept (also known as VEGF Trap or ziv-aflibercept in the United States) in preclinical tumor models with a range of responses to anti-VEGF therapy, including Colo205 human colorectal carcinoma (highly sensitive), C6 rat glioblastoma (moderately sensitive), and HT1080 human fibrosarcoma (resistant), and correlated these changes to long-term tumor growth inhibition. We found that an overall decrease in tumor vessel perfusion, assessed by dynamic contrast-enhanced ultrasound (DCE-US), and increases in tumor hypoxia correlated well with long-term tumor growth inhibition, whereas changes in vascular gene expression and microvessel density did not. Our findings support previous clinical studies showing that decreased tumor perfusion after anti-VEGF therapy (measured by DCE-US) correlated with response. Thus, measuring tumor perfusion changes shortly after treatment with VEGF inhibitors, or possibly other anti-angiogenic therapies, may be useful to predict treatment efficacy. PMID:23238831

  5. Inhibition of Vascularization in Tumor Growth

    NASA Astrophysics Data System (ADS)

    Scalerandi, M.; Sansone, B. Capogrosso

    2002-11-01

    The transition to a vascular phase is a prerequisite for fast tumor growth. During the avascular phase, the neoplasm feeds only from the (relatively few) existing nearby blood vessels. During angiogenesis, the number of capillaries surrounding and infiltrating the tumor increases dramatically. A model which includes physical and biological mechanisms of the interactions between the tumor and vascular growth describes the avascular-vascular transition. Numerical results agree with clinical observations and predict the influence of therapies aiming to inhibit the transition.

  6. 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. PMID:25972739

  7. 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

  8. 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

  9. 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. PMID:27445440

  10. A Novel Pentamethoxyflavone Down-Regulates Tumor Cell Survival and Proliferative and Angiogenic Gene Products through Inhibition of IκB Kinase Activation and Sensitizes Tumor Cells to Apoptosis by Cytokines and Chemotherapeutic Agents

    PubMed Central

    Phromnoi, Kanokkarn; Reuter, Simone; Sung, Bokyung; Prasad, Sahdeo; Kannappan, Ramaswamy; Yadav, Vivek R.; Chanmahasathien, Wisinee; Limtrakul, Pornngarm

    2011-01-01

    Most anticancer drugs have their origin in traditional medicinal plants. We describe here a flavone, 5,3′-dihydroxy-3,6,7,8,4′-pentamethoxyflavone (PMF), from the leaves of the Thai plant Gardenia obtusifolia, that has anti-inflammatory and anticancer potential. Because the nuclear factor-κB (NF-κB) pathway is linked to inflammation and tumorigenesis, we investigated the effect of PMF on this pathway. We found that PMF suppressed NF-κB activation induced by inflammatory agents, tumor promoters, and carcinogens. This suppression was not specific to the cell type. Although PMF did not directly modify the ability of NF-κB proteins to bind to DNA, it inhibited IκBα (inhibitory subunit of NF-κB) kinase, leading to suppression of phosphorylation and degradation of IκBα, and suppressed consequent p65 nuclear translocation, thus abrogating NF-κB-dependent reporter gene expression. Suppression of the NF-κB cell signaling pathway by the flavone led to the inhibition of expression of NF-κB-regulated gene products that mediate inflammation (cyclooxygenase-2), survival (XIAP, survivin, Bcl-xL, and cFLIP), proliferation (cyclin D1), invasion (matrix metalloproteinase-9), and angiogenesis (vascular endothelial growth factor). Suppression of antiapoptotic gene products by PMF correlated with the enhancement of apoptosis induced by tumor necrosis factor-α and the chemotherapeutic agents cisplatin, paclitaxel, and 5-flurouracil. Overall, our results indicate that PMF suppresses the activation of NF-κB and NF-κB-regulated gene expression, leading to the enhancement of apoptosis. This is the first report to demonstrate that this novel flavone has anti-inflammatory and anticancer effects by targeting the IKK complex. PMID:20930110

  11. Anandamide inhibits breast tumor-induced angiogenesis

    PubMed Central

    Picardi, P; Ciaglia, E; Proto, MC; Pisanti, S

    2014-01-01

    Breast cancer is one of the most frequently diagnosed malignancies and a leading cause of cancer death in women. Great advances in the treatment of primary tumors have led to a significant increment in the overall survival rates, however recurrence and metastatic disease, the underlying cause of death, are still a medical challenge. Breast cancer is highly dependent on neovascularization to progress. In the last years several anti-angiogenic drugs have been developed and administered to patients in combination with chemotherapeutic drugs. Collected preclinical evidence has proposed the endocannabinoid system as a potential target in cancer. The endocannabinoid anandamide has been reported to affect breast cancer growth at multiple levels, by inhibiting proliferation, migration and invasiveness in vitro and in vivo and by directly inhibiting angiogenesis. Aim of the present work is to investigate if anandamide is able to affect the proangiogenic phenotype of the highly invasive and metastatic breast cancer cells MDA-MB-231. We found that following anandamide treatment, MDAMB-231 cells lose their ability to stimulate endothelial cells proliferation in vitro, due to a significant inhibition of all the pro-angiogenic factors produced by these cells. This finding adds another piece of evidence to the anti-tumor efficacy of anandamide in breast cancer. PMID:25147760

  12. BmKCT toxin inhibits glioma proliferation and tumor metastasis.

    PubMed

    Fan, Shaozhong; Sun, Zhengbo; Jiang, Dahe; Dai, Chao; Ma, Yibao; Zhao, Zhenhuan; Liu, Hui; Wu, Yingliang; Cao, Zhijian; Li, Wenxin

    2010-05-28

    Malignant gliomas are the most common primary brain tumors associated with significant morbidity and mortality. How to target the tumor in situ, and inhibit tumor cell proliferation and invasion is the key for therapy. Gliomas express a glioma-specific chloride ion channel that is sensitive to toxins including BmKCT. In the current study, the inhibitory effect of BmKCT on glioma growth was observed in vivo using the glioma/SD rat model. Furthermore, BmKCT prevented the metastasis of glioma cells in vivo. Moreover, biodistribution experiments with (l3l)I-labeled or Cy5.5-conjugated BmKCT revealed that BmKCT selectively targeted the glioma in situ. Our data suggest that BmKCT could be exploited as a potential therapeutic for glioma diagnosis and therapy. PMID:19906483

  13. 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.

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

    PubMed Central

    Daldrup-Link, Heike E.; Mohanty, Suchismita; Ansari, Celina; Lenkov, Olga; Shaw, Aubie; 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

  15. Low doses of PEG-coated gold nanoparticles sensitize solid tumors to cold plasma by blocking the PI3K/AKT-driven signaling axis to suppress cellular transformation by inhibiting growth and EMT.

    PubMed

    Kaushik, Nagendra Kumar; Kaushik, Neha; Yoo, Ki Chun; Uddin, Nizam; Kim, Ju Sung; Lee, Su Jae; Choi, Eun Ha

    2016-05-01

    Metastasis, the primary cause of tumor cell transformation, is often activated during cancer invasion and progression and is associated with poor therapeutic outcomes. The effects of combined treatments that included PEG-coated gold nanoparticles (GNP) and cold plasma on epithelial-mesenchymal transition (EMT) and the maintenance of cancer stem cells (CSC) have not been described so far. Here, we report that co-treatment with GNP and cold plasma inhibited proliferation in cancer cells by abolishing the activation of the PI3K/AKT signaling axis. In addition, co-treatment reversed EMT in solid tumor cells by reducing the secretion of a number of proteins, resulting in the upregulation of epithelial markers such as E-cadherin along with down-regulation of N-Cadherin, Slug and Zeb-1. The inhibition of the PI3K/AKT pathway and the reversal of EMT by co-treatment prevented tumor cells growth in solid tumors. Furthermore, we show that GNP and plasma also suppresses tumor growth by decreasing mesenchymal markers in tumor xenograft mice models. Importantly, co-treatment resulted in a substantial decrease in sphere formation and the self-renewal capacity of glioma-like stem cells. Together, these results indicate a direct link between a decrease of EMT and an increase in cell death in solid tumors following co-treatment with cold plasma and GNP. PMID:26921841

  16. Inhibition of rate of tumor growth by creatine and cyclocreatine.

    PubMed Central

    Miller, E E; Evans, A E; Cohn, M

    1993-01-01

    Growth rate inhibition of subcutaneously implanted tumors results from feeding rats and athymic nude mice diets containing 1% cyclocreatine or 1%, 2%, 5%, or 10% creatine. The tumors studied included rat mammary tumors (Ac33tc in Lewis female rats and 13762A in Fischer 344 female rats), rat sarcoma MCI in Lewis male rats, and tumors resulting from the injection of two human neuroblastoma cell lines, IMR-5 and CHP-134, in athymic nude mice. Inhibition was observed regardless of the time experimental diets were administered, either at the time of tumor implantation or after the appearance of palpable tumors. For mammary tumor Ac33tc, the growth inhibition during 24 days after the implantation was approximately 50% for both 1% cyclocreatine and 1% creatine, and inhibition increased as creatine was increased from 2% to 10% of the diet. For the other rat mammary tumor (13762A), there was approximately 35% inhibition by both 1% cyclocreatine and 2% creatine. In the case of the MCI sarcoma, the inhibitory effect appeared more pronounced at earlier periods of growth, ranging from 26% to 41% for 1% cyclocreatine and from 30% to 53% for 1% creatine; there was no significant difference in growth rate between the tumors in the rats fed 1% and 5% creatine. The growth rate of tumors in athymic nude mice, produced by implantation of the human neuroblastoma IMR-5 cell line, appeared somewhat more effectively inhibited by 1% cyclocreatine than by 1% creatine, and 5% creatine feeding was most effective. For the CHP-134 cell line, 33% inhibition was observed for the 1% cyclocreatine diet and 71% for the 5% creatine diet. In several experiments, a delay in appearance of tumors was observed in animals on the experimental diets. In occasional experiments, neither additive inhibited tumor growth rate for the rat tumors or the athymic mouse tumors. Images Fig. 3 PMID:8475072

  17. NMR exposure sensitizes tumor cells to apoptosis.

    PubMed

    Ghibelli, L; Cerella, C; Cordisco, S; Clavarino, G; Marazzi, S; De Nicola, M; Nuccitelli, S; D'Alessio, M; Magrini, A; Bergamaschi, A; Guerrisi, V; Porfiri, L M

    2006-03-01

    NMR technology has dramatically contributed to the revolution of image diagnostic. NMR apparatuses use combinations of microwaves over a homogeneous strong (1 Tesla) static magnetic field. We had previously shown that low intensity (0.3-66 mT) static magnetic fields deeply affect apoptosis in a Ca2+ dependent fashion (Fanelli et al., 1999 FASEBJ., 13;95-102). The rationale of the present study is to examine whether exposure to the static magnetic fields of NMR can affect apoptosis induced on reporter tumor cells of haematopoietic origin. The impressive result was the strong increase (1.8-2.5 fold) of damage-induced apoptosis by NMR. This potentiation is due to cytosolic Ca2+ overload consequent to NMR-promoted Ca2+ influx, since it is prevented by intracellular (BAPTA-AM) and extracellular (EGTA) Ca2+ chelation or by inhibition of plasma membrane L-type Ca2+ channels. Three-days follow up of treated cultures shows that NMR decrease long term cell survival, thus increasing the efficiency of cytocidal treatments. Importantly, mononuclear white blood cells are not sensitised to apoptosis by NMR, showing that NMR may increase the differential cytotoxicity of antitumor drugs on tumor vs normal cells. This strong, differential potentiating effect of NMR on tumor cell apoptosis may have important implications, being in fact a possible adjuvant for antitumor therapies. PMID:16528477

  18. Inhibition of IL-17A in tumor microenvironment augments cytotoxicity of tumor-infiltrating lymphocytes in tumor-bearing mice.

    PubMed

    Hayata, Keiji; Iwahashi, Makoto; Ojima, Toshiyasu; Katsuda, Masahiro; Iida, Takeshi; Nakamori, Mikihito; Ueda, Kentaro; Nakamura, Masaki; Miyazawa, Motoki; Tsuji, Toshiaki; Yamaue, Hiroki

    2013-01-01

    It remains controversial whether IL-17A promotes or inhibits cancer progression. We hypothesized that IL-17A that is locally produced in the tumor microenvironment has an important role in angiogenesis and tumor immunity. We investigated the effect of inhibiting IL-17A at tumor sites on tumor growth and on local and systemic anti-tumor immunity. MC38 or B16 cells were inoculated subcutaneously into mice, and intratumoral injection of an adenovirus vector expressing siRNA against the mouse IL-17A gene (Ad-si-IL-17) significantly inhibited tumor growth in both tumor models compared with control mice. Inhibition of IL-17A at tumor sites significantly suppressed CD31, MMP9, and VEGF expression in tumor tissue. The cytotoxic activity of CD8(+) T cells from tumor-infiltrating lymphocytes in mice treated with Ad-si-IL-17 was significantly higher than in control mice; however, CD8(+) T cells from splenocytes had similar activity levels. Suppression of IL-17A at tumor sites led to a Th1-dominant environment, and moreover, eliminated myeloid-derived suppressor cells and regulatory T cells at tumor sites but not in splenocytes. In conclusion, blockade of IL-17A at tumor sites helped suppress tumor growth by inhibiting angiogenesis as well as cytotoxic T lymphocytes activation at tumor sites. PMID:23372655

  19. Clodronate inhibits tumor angiogenesis in mouse models of ovarian cancer

    PubMed Central

    Reusser, Nicole M; Dalton, Heather J; Pradeep, Sunila; Gonzalez-Villasana, Vianey; Jennings, Nicholas B; Vasquez, Hernan G; Wen, Yunfei; Rupaimoole, Rajesh; Nagaraja, Archana S; Gharpure, Kshipra; Miyake, Takahito; Huang, Jie; Hu, Wei; Lopez-Berestein, Gabriel; Sood, Anil K

    2014-01-01

    Purpose Bisphosphonates have been shown to inhibit and deplete macrophages. The effects of bisphosphonates on other cell types in the tumor microenvironment have been insufficiently studied. Here, we sought to determine the effects of bisphosphonates on ovarian cancer angiogenesis and growth via their effect on the microenvironment, including macrophage, endothelial and tumor cell populations. Experimental Design Using in vitro and in vivo models, we examined the effects of clodronate on angiogenesis and macrophage density, and the overall effect of clodronate on tumor size and metastasis. Results Clodronate inhibited the secretion of pro-angiogenic cytokines by endothelial cells and macrophages, and decreased endothelial migration and capillary tube formation. In treated mice, clodronate significantly decreased tumor size, number of tumor nodules, number of tumor-associated macrophages and tumor capillary density. Conclusions Clodronate is a potent inhibitor of tumor angiogenesis. These results highlight clodronate as a potential therapeutic for cancer. PMID:24841852

  20. The tumor microenvironment underlies acquired resistance to CSF-1R inhibition in gliomas.

    PubMed

    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

    2016-05-20

    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 although overall survival is significantly prolonged, tumors recur in >50% of mice. Gliomas reestablish 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-1 (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

  1. 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

  2. INHIBITION OF INTERCELLULAR COMMUNICATION BETWEEN MOUSE HEPATOCYTES BY TUMOR PROMOTERS

    EPA Science Inventory

    Tumor promoters can inhibit gap junction-mediated intercellular communication in cultured cells. The authors evaluated the effects of tumor promoters on intercellular communication between B6C3F1 mouse hepatocytes in primary culture. Intercellular communication between donor and ...

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

    PubMed

    Lee, Hye Lim; Park, Sang Ho; 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

    2015-03-30

    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

  4. Oncogene-mediated tumor transformation sensitizes cells to autophagy induction.

    PubMed

    Gargini, Ricardo; García-Escudero, Vega; Izquierdo, Marta; Wandosell, Francisco

    2016-06-01

    The process of tumorigenesis induces alterations in numerous cellular pathways including the main eukaryotic metabolic routes. It has been recently demonstrated that autophagy is part of the oncogene-induced senescence phenotype although its role in tumor establishment has not been completely clarified. In the present study, we showed that non‑transformed cells are sensitized to mitochondrial stress and autophagy induction when they are transformed by oncogenes such as c-Myc or Ras. We observed that overexpression of c-Myc or Ras increased AMP-activated protein kinase (AMPK) phosphorylation and the expression of p62, a known partner for degradation by autophagy. The activation of AMPK was found to favor the activation of FoxO3 which was prevented by the inhibition of AMPK. The transcriptional activation mediated by FoxO3 upregulated genes such as BNIP3 and LC3. Finally, the transformation by oncogenes such as c-Myc and Ras predisposes tumor cells to autophagy induction as a consequence of mitochondrial stress and impairs tumor growth in vitro and in vivo, which may have therapeutic implications. PMID:27035659

  5. Wee1 inhibition potentiates Wip1-dependent p53-negative tumor cell death during chemotherapy

    PubMed Central

    Clausse, V; Goloudina, A R; Uyanik, B; Kochetkova, E Y; Richaud, S; Fedorova, O A; Hammann, A; Bardou, M; Barlev, N A; Garrido, C; Demidov, O N

    2016-01-01

    Inactivation of p53 found in more than half of human cancers is often associated with increased tumor resistance to anti-cancer therapy. We have previously shown that overexpression of the phosphatase Wip1 in p53-negative tumors sensitizes them to chemotherapeutic agents, while protecting normal tissues from the side effects of anti-cancer treatment. In this study, we decided to search for kinases that prevent Wip1-mediated sensitization of cancer cells, thereby interfering with efficacy of genotoxic anti-cancer drugs. To this end, we performed a flow cytometry-based screening in order to identify kinases that regulated the levels of γH2AX, which were used as readout. Another criterion of the screen was increased sensitivity of p53-negative tumor cells to cisplatin (CDDP) in a Wip1-dependent manner. We have found that a treatment with a low dose (75 nM) of MK-1775, a recently described specific chemical inhibitor of Wee1, decreases CDDP-induced H2AX phosphorylation in p53-negative cells and enhances the Wip1-sensitization of p53-negative tumors. We were able to reduce CDDP effective concentration by 40% with a combination of Wip1 overexpression and Wee1 kinase inhibition. We have observed that Wee1 inhibition potentiates Wip1-dependent tumor sensitization effect by reducing levels of Hipk2 kinase, a negative regulator of Wip1 pathway. In addition, during CDDP treatment, the combination of Wee1 inhibition and Wip1 overexpression has a mild but significant protective effect in normal cells and tissues. Our results indicate that inhibition of the negative regulators of Wip1 pathway, Wee1 and Hipk2, in p53-negative tumors could potentiate efficiency of chemotherapeutic agents without concomitant increase of cytotoxicity in normal tissues. The development and clinical use of Wee1 and Hipk1 kinase chemical inhibitors might be a promising strategy to improve anti-cancer therapy. PMID:27077811

  6. Wee1 inhibition potentiates Wip1-dependent p53-negative tumor cell death during chemotherapy.

    PubMed

    Clausse, V; Goloudina, A R; Uyanik, B; Kochetkova, E Y; Richaud, S; Fedorova, O A; Hammann, A; Bardou, M; Barlev, N A; Garrido, C; Demidov, O N

    2016-01-01

    Inactivation of p53 found in more than half of human cancers is often associated with increased tumor resistance to anti-cancer therapy. We have previously shown that overexpression of the phosphatase Wip1 in p53-negative tumors sensitizes them to chemotherapeutic agents, while protecting normal tissues from the side effects of anti-cancer treatment. In this study, we decided to search for kinases that prevent Wip1-mediated sensitization of cancer cells, thereby interfering with efficacy of genotoxic anti-cancer drugs. To this end, we performed a flow cytometry-based screening in order to identify kinases that regulated the levels of γH2AX, which were used as readout. Another criterion of the screen was increased sensitivity of p53-negative tumor cells to cisplatin (CDDP) in a Wip1-dependent manner. We have found that a treatment with a low dose (75 nM) of MK-1775, a recently described specific chemical inhibitor of Wee1, decreases CDDP-induced H2AX phosphorylation in p53-negative cells and enhances the Wip1-sensitization of p53-negative tumors. We were able to reduce CDDP effective concentration by 40% with a combination of Wip1 overexpression and Wee1 kinase inhibition. We have observed that Wee1 inhibition potentiates Wip1-dependent tumor sensitization effect by reducing levels of Hipk2 kinase, a negative regulator of Wip1 pathway. In addition, during CDDP treatment, the combination of Wee1 inhibition and Wip1 overexpression has a mild but significant protective effect in normal cells and tissues. Our results indicate that inhibition of the negative regulators of Wip1 pathway, Wee1 and Hipk2, in p53-negative tumors could potentiate efficiency of chemotherapeutic agents without concomitant increase of cytotoxicity in normal tissues. The development and clinical use of Wee1 and Hipk1 kinase chemical inhibitors might be a promising strategy to improve anti-cancer therapy. PMID:27077811

  7. Nanoelectroablation of Murine Tumors Triggers a CD8-Dependent Inhibition of Secondary Tumor Growth

    PubMed Central

    Nuccitelli, Richard; Berridge, Jon Casey; Mallon, Zachary; Kreis, Mark; Athos, Brian; Nuccitelli, Pamela

    2015-01-01

    We have used both a rat orthotopic hepatocellular carcinoma model and a mouse allograft tumor model to study liver tumor ablation with nanosecond pulsed electric fields (nsPEF). We confirm that nsPEF treatment triggers apoptosis in rat liver tumor cells as indicated by the appearance of cleaved caspase 3 and 9 within two hours after treatment. Furthermore we provide evidence that nsPEF treatment leads to the translocation of calreticulin (CRT) to the cell surface which is considered a damage-associated molecular pattern indicative of immunogenic cell death. We provide direct evidence that nanoelectroablation triggers a CD8-dependent inhibition of secondary tumor growth by comparing the growth rate of secondary orthotopic liver tumors in nsPEF-treated rats with that in nsPEF-treated rats depleted of CD8+ cytotoxic T-cells. The growth of these secondary tumors was severely inhibited as compared to tumor growth in CD8-depleated rats, with their average size only 3% of the primary tumor size after the same one-week growth period. In contrast, when we depleted CD8+ T-cells the second tumor grew more robustly, reaching 54% of the size of the first tumor. In addition, we demonstrate with immunohistochemistry that CD8+ T-cells are highly enriched in the secondary tumors exhibiting slow growth. We also showed that vaccinating mice with nsPEF-treated isogenic tumor cells stimulates an immune response that inhibits the growth of secondary tumors in a CD8+-dependent manner. We conclude that nanoelectroablation triggers the production of CD8+ cytotoxic T-cells resulting in the inhibition of secondary tumor growth. PMID:26231031

  8. 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

  9. 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

    2016-01-01

    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

  10. Delivery of tumor-homing TRAIL sensitizer with long-acting TRAIL as a therapy for TRAIL-resistant tumors.

    PubMed

    Oh, Yumin; Swierczewska, Magdalena; Kim, Tae Hyung; Lim, Sung Mook; Eom, Ha Na; Park, Jae Hyung; Na, Dong Hee; Kim, Kwangmeyung; Lee, Kang Choon; Pomper, Martin G; Lee, Seulki

    2015-12-28

    Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) has attracted great interest as a cancer therapy because it selectively induces death receptor (DR)-mediated apoptosis in cancer cells while sparing normal tissue. However, recombinant human TRAIL demonstrates limited therapeutic efficacy in clinical trials, possibly due to TRAIL-resistance of primary cancers and its inherent short half-life. Here we introduce drug delivery approaches to maximize in vivo potency of TRAIL in TRAIL-resistant tumor xenografts by (1) extending the half-life of the ligand with PEGylated TRAIL (TRAILPEG) and (2) concentrating a TRAIL sensitizer, selected from in vitro screening, in tumors via tumor-homing nanoparticles. Antitumor efficacy of TRAILPEG with tumor-homing sensitizer was evaluated in HCT116 and HT-29 colon xenografts. Western blot, real-time PCR, immunohistochemistry and cell viability assays were employed to investigate mechanisms of action and antitumor efficacy of the combination. We discovered that doxorubicin (DOX) sensitizes TRAIL-resistant HT-29 colon cancer cells to TRAIL by upregulating mRNA expression of DR5 by 60% in vitro. Intravenously administered free DOX does not effectively upregulate DR5 in tumor tissues nor demonstrate synergy with TRAILPEG in HT-29 xenografts, but rather introduces significant systemic toxicity. Alternatively, when DOX was encapsulated in hyaluronic acid-based nanoparticles (HAC/DOX) and intravenously administered with TRAILPEG, DR-mediated apoptosis was potentiated in HT-29 tumors by upregulating DR5 protein expression by 70% and initiating both extrinsic and intrinsic apoptotic pathways with reduced systemic toxicity compared to HAC/DOX or free DOX combined with TRAILPEG (80% vs. 40% survival rate; 75% vs. 34% tumor growth inhibition). This study demonstrates a unique approach to overcome TRAIL-based therapy drawbacks using sequential administration of a tumor-homing TRAIL sensitizer and long-acting TRAILPEG. PMID:26381901

  11. Lovastatin and tumor necrosis factor-alpha exhibit potentiated antitumor effects against Ha-ras-transformed murine tumor via inhibition of tumor-induced angiogenesis.

    PubMed

    Feleszko, W; Bałkowiec, E Z; Sieberth, E; Marczak, M; Dabrowska, A; Giermasz, A; Czajka, A; Jakóbisiak, M

    1999-05-17

    Lovastatin, a drug commonly used in the treatment of hypercholesterolemia, has previously been reported to exert potentiated antitumor activity when combined with either tumor necrosis factor-alpha (TNF-alpha), cisplatin or doxorubicin in a melanoma model in mice. Since lovastatin interferes with the function of ras oncogene-encoded (Ras) proteins, we have investigated the antitumor activity of lovastatin and TNF-alpha using a Ha-ras-transformed murine tumor model. In in vitro studies, lovastatin inhibited the growth of cells transformed with Ha-ras oncogene (Ras-3T3 and HBL100-ras cells) more effectively than control NIH-3T3 and HBL100-neo cells. In in vivo experiments, the Ras-3T3 tumor demonstrated significantly increased sensitivity to combined treatment with both lovastatin (50 mg/kg) and TNF-alpha (1 microg/day) compared with either agent alone. Combined treatment with both agents also resulted in greater inhibition of blood-vessel formation. Ras-3T3 tumor cells produced increased amounts of vascular endothelial growth factor (VEGF) and lovastatin effectively suppressed VEGF production by these cells. Our results suggest that lovastatin increases antitumor activity of TNF-alpha against tumor cells transformed with v-Ha-ras oncogene via inhibition of tumor-induced blood-vessel formation. PMID:10225445

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

    PubMed

    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

  13. 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

  14. 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

  15. Sensitization of pancreatic cancer stem cells to gemcitabine by Chk1 inhibition.

    PubMed

    Venkatesha, Venkatasubbaiah A; Parsels, Leslie A; Parsels, Joshua D; Zhao, Lili; Zabludoff, Sonya D; Simeone, Diane M; Maybaum, Jonathan; Lawrence, Theodore S; Morgan, Meredith A

    2012-06-01

    Checkpoint kinase 1 (Chk1) inhibition sensitizes pancreatic cancer cells and tumors to gemcitabine. We hypothesized that Chk1 inhibition would sensitize pancreatic cancer stem cells to gemcitabine. We tested this hypothesis by using two patient-derived xenograft models (designated J and F) and the pancreatic cancer stem cell markers CD24, CD44, and ESA. We determined the percentage of marker-positive cells and their tumor-initiating capacity (by limiting dilution assays) after treatment with gemcitabine and the Chk1 inhibitor, AZD7762. We found that marker-positive cells were significantly reduced by the combination of gemcitabine and AZD7762. In addition, secondary tumor initiation was significantly delayed in response to primary tumor treatment with gemcitabine + AZD7762 compared with control, gemcitabine, or AZD7762 alone. Furthermore, for the same number of stem cells implanted from gemcitabine- versus gemcitabine + AZD7762-treated primary tumors, secondary tumor initiation at 10 weeks was 83% versus 43%, respectively. We also found that pS345 Chk1, which is a measure of DNA damage, was induced in marker-positive cells but not in the marker-negative cells. These data demonstrate that Chk1 inhibition in combination with gemcitabine reduces both the percentage and the tumor-initiating capacity of pancreatic cancer stem cells. Furthermore, the finding that the Chk1-mediated DNA damage response was greater in stem cells than in non-stem cells suggests that Chk1 inhibition may selectively sensitize pancreatic cancer stem cells to gemcitabine, thus making Chk1 a potential therapeutic target for improving pancreatic cancer therapy. PMID:22787433

  16. BMP4/Thrombospondin-1 loop paracrinically inhibits tumor angiogenesis and suppresses the growth of solid tumors.

    PubMed

    Tsuchida, R; Osawa, T; Wang, F; Nishii, R; Das, B; Tsuchida, S; Muramatsu, M; Takahashi, T; Inoue, T; Wada, Y; Minami, T; Yuasa, Y; Shibuya, M

    2014-07-17

    Bone morphogenetic protein 4 (BMP4) has potential as an anticancer agent. Recent studies have suggested that BMP4 inhibits the survival of cancer stem cells (CSCs) of neural and colon cancers. Here, we showed that BMP4 paracrinically inhibited tumor angiogenesis via the induction of Thrombospondin-1 (TSP1), and consequently suppressed tumor growth in vivo. Although HeLa (human cervical cancer), HCI-H460-LNM35 (highly metastatic human lung cancer) and B16 (murine melanoma) cells did not respond to the BMP4 treatment in vitro, the growth of xeno- and allografts of these cells was suppressed via reductions in tumor angiogenesis after intraperitoneal treatment with BMP4. When we assessed the mRNA expression of major angiogenesis-related factors in grafted tumors, we found that the expression of TSP1 was significantly upregulated by BMP4 administration. We then confirmed that BMP4 was less effective in suppressing the tumor growth of TSP1-knockdown cancer cells. Furthermore, we found that BMP4 reduced vascular endothelial growth factor (VEGF) expression in vivo in a TSP1-dependent manner, which indicates that BMP4 interfered with the stabilization of tumor angiogenesis. In conclusion, the BMP4/TSP1 loop paracrinically suppressed tumor angiogenesis in the tumor microenvironment, which subsequently reduced the growth of tumors. BMP4 may become an antitumor agent and open a new field of antiangiogenic therapy. PMID:24013228

  17. Inhibition of endothelial Cdk5 reduces tumor growth by promoting non-productive angiogenesis

    PubMed Central

    Merk, Henriette; Zhang, Siwei; Lehr, Thorsten; Müller, Christoph; Ulrich, Melanie; Bibb, James A.; Adams, Ralf H.; Bracher, Franz; Zahler, Stefan; Vollmar, Angelika M.; Liebl, Johanna

    2016-01-01

    Therapeutic success of VEGF-based anti-angiogenic tumor therapy is limited due to resistance. Thus, new strategies for anti-angiogenic cancer therapy based on novel targets are urgently required. Our previous in vitro work suggested that small molecule Cdk5 inhibitors affect angiogenic processes such as endothelial migration and proliferation. Moreover, we recently uncovered a substantial role of Cdk5 in the development of lymphatic vessels. Here we pin down the in vivo impact of endothelial Cdk5 inhibition in angiogenesis and elucidate the underlying mechanism in order to judge the potential of Cdk5 as a novel anti-angiogenic and anti-cancer target. By the use of endothelial-specific Cdk5 knockout mouse models and various endothelial and tumor cell based assays including human tumor xenograft models, we show that endothelial-specific knockdown of Cdk5 results in excessive but non-productive angiogenesis during development but also in tumors, which subsequently leads to inhibition of tumor growth. As Cdk5 inhibition disrupted Notch function by reducing the generation of the active Notch intracellular domain (NICD) and Cdk5 modulates Notch-dependent endothelial cell proliferation and sprouting, we propose that the Dll4/Notch driven angiogenic signaling hub is an important and promising mechanistic target of Cdk5. In fact, Cdk5 inhibition can sensitize tumors to conventional anti-angiogenic treatment as shown in tumor xenograft models. In summary our data set the stage for Cdk5 as a drugable target to inhibit Notch-driven angiogenesis condensing the view that Cdk5 is a promising target for cancer therapy. PMID:26755662

  18. 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

  19. Three-dimensional culture sensitizes epithelial ovarian cancer cells to EZH2 methyltransferase inhibition

    PubMed Central

    Amatangelo, Michael D.; Garipov, Azat; Li, Hua; Conejo-Garcia, Jose R.; Speicher, David W.; Zhang, Rugang

    2013-01-01

    Inhibitors of EZH2 methyltransferase activity have been demonstrated to selectively suppress the growth of diffused large B cell lymphoma (DLBCL) cells with gain-of-function mutations in EZH2, while exhibiting very limited effects on the growth of DLBCL cells with wild-type EZH2. Given that EZH2 is often overexpressed but not mutated in solid tumors, it is important to investigate the determinants of sensitivity of solid tumor cells to EZH2 inhibitors. In the current study, we show that three-dimensional (3D) culture of epithelial ovarian cancer (EOC) cells that overexpress EZH2 sensitizes these cells to EZH2 methyltransferase inhibition. Treatment of EOC cells with GSK343, a specific inhibitor of EZH2 methyltransferase, decreases the level of H3K27Me3, the product of EZH2’s enzymatic activity. However, GSK343 exhibited limited effects on the growth of EOC cells in conventional two-dimensional (2D) culture. In contrast, GSK343 significantly suppressed the growth of EOC cells cultured in 3D matrigel extracellular matrix (ECM), which more closely mimics the tumor microenvironment in vivo. Notably, GSK343 induces apoptosis of EOC cells in 3D but not 2D culture. In addition, GSK343 significantly inhibited the invasion of EOC cells. In summary, we show that the 3D ECM sensitizes EOC cells to EZH2 methyltransferase inhibition, which suppresses cell growth, induces apoptosis and inhibits invasion. Our findings imply that in EZH2 wild-type solid tumors, the ECM tumor microenvironment plays an important role in determining sensitivity to EZH2 inhibition and suggest that targeting the ECM represents a novel strategy for enhancing EZH2 inhibitor efficacy. PMID:23759589

  20. Sulindac sulfide selectively inhibits growth and induces apoptosis of human breast tumor cells by PDE5 inhibition, elevation of cGMP, and activation of PKG

    PubMed Central

    Tinsley, Heather N.; Gary, Bernard D.; Keeton, Adam B.; Zhang, Wei; Abadi, Ashraf H.; Reynolds, Robert C.; Piazza, Gary A.

    2009-01-01

    Sulindac displays promising antineoplastic activity, but toxicities from cyclooxygenase (COX) inhibition limit its use for chemoprevention. Previous reports suggest that its anticancer properties may be attributed to a COX-independent mechanism, although alternative targets have not been well defined. Here we show that sulindac sulfide (SS) induces apoptosis and inhibits the growth of human breast tumor cells with IC50 values of 60-85 μM. Within the same concentration range, SS inhibited cGMP hydrolysis in tumor cell lysates, but did not affect cAMP hydrolysis. SS did not induce apoptosis of normal human mammary epithelial cells (HMEC), nor did it inhibit PDE activity in HMEC lysates. SS increased intracellular cGMP levels and activated protein kinase G in breast tumor cells, but not HMEC. The guanylyl cyclase (GC) activator, NOR-3, and cGMP PDE inhibitors, trequinsin and MY5445, displayed similar growth inhibitory activity as SS, but the adenylyl cyclase activator, forskolin, and other PDE inhibitors had no effect. Moreover, GC activation increased the sensitivity of tumor cells to SS, while GC inhibition reduced sensitivity. By comparing PDE isozyme profiles in breast tumor cells with HMEC and determining the sensitivity of recombinant PDE isozymes to SS, PDE5 was found to be overexpressed in breast tumor cells and selectively inhibited by SS. The mechanism of SS binding to the catalytic domain of PDE5 was revealed by molecular modeling. These data suggest that PDE5 inhibition is responsible for the breast tumor cell growth inhibitory and apoptosis inducing activity of SS and may contribute to the chemopreventive properties of sulindac. PMID:19996273

  1. Inhibition of TGFBIp expression reduces lymphangiogenesis and tumor metastasis.

    PubMed

    Maeng, Y-S; Aguilar, B; Choi, S-I; Kim, E K

    2016-01-14

    Transforming growth factor-β-induced protein (TGFBIp) is an extracellular matrix protein that has a role in a wide range of pathological conditions. However, the role of TGFBIp signaling in lymphangiogenesis is poorly understood. The purpose of this study was therefore to analyze the effects of TGFBIp on lymphangiogenesis and determine whether TGFBIp-related lymphangiogenesis is important for the metastasis of tumor cells. TGFBIp increased adhesion, migration, and morphologic differentiation of human lymphatic endothelial cells (LECs), consistent with an increase in lymphatic vessel sprouting in a three-dimensional lymphatic ring assay. TGFBIp also induced phosphorylation of intracellular signaling molecules SRC, FAK, AKT, JNK and ERK. TGFBIp-induced lymphatic vessel sprouting was inhibited by addition of anti-integrin β3 antibody and pharmacologic inhibitors of FAK, AKT, JNK or ERK. TGFBIp increased both CCL21 expression in LECs, a chemokine that actively recruits tumor cells expressing the cognate chemokine receptors to lymphatic vessels and LEC permeability by inducing the dissociation of VE-cadherin junctions between LECs via the activation of SRC signaling. In vivo, inhibition of TGFBIp expression in SW620 cancer cells dramatically reduced tumor lymphangiogenesis and metastasis. Collectively, our findings demonstrate that TGFBIp is a lymphangiogenic factor contributing to tumor dissemination and represents a potential target to inhibit metastasis. PMID:25772247

  2. X-ray sensitivity of human tumor cells in vitro

    SciTech Connect

    Weichselbaum, R.R.; Nove, J.; Little, J.B.

    1980-04-01

    Clonally-derived cells from ten human malignant tumors considered radiocurable (breast, neuroblastoma, medulloblastoma) or non-radiocurable (osteosarcoma, hypernephroma, glioblastoma, melanoma) were studied in cell culture and their in vitro x-ray survival curve parameters determined (anti n, D/sub 0/). There were no significant differences among the tumor cell lines suggesting that survival parameters in vitro do not explain differences in clinical radiocurability. Preliminary investigation with density inhibited human tumor cells indicate that such an approach may yield information regarding inherent cellular differences in radiocurability.

  3. 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

  4. Dll4 Inhibition plus Aflibercept Markedly Reduces Ovarian Tumor Growth.

    PubMed

    Huang, Jie; Hu, Wei; Hu, Limin; Previs, Rebecca A; Dalton, Heather J; Yang, Xiao-Yun; Sun, Yunjie; McGuire, Michael; Rupaimoole, Rajesha; Nagaraja, Archana S; Kang, Yu; Liu, Tao; Nick, Alpa M; Jennings, Nicholas B; Coleman, Robert L; Jaffe, Robert B; Sood, Anil K

    2016-06-01

    Delta-like ligand 4 (Dll4), one of the Notch ligands, is overexpressed in ovarian cancer, especially in tumors resistant to anti-VEGF therapy. Here, we examined the biologic effects of dual anti-Dll4 and anti-VEGF therapy in ovarian cancer models. Using Dll4-Fc blockade and anti-Dll4 antibodies (murine REGN1035 and human REGN421), we evaluated the biologic effects of Dll4 inhibition combined with aflibercept or chemotherapy in orthotopic mouse models of ovarian cancer. We also examined potential mechanisms by which dual Dll4 and VEGF targeting inhibit tumor growth using immunohistochemical staining for apoptosis and proliferation markers. Reverse-phase protein arrays were used to identify potential downstream targets of Dll4 blockade. Dual targeting of VEGF and Dll4 with murine REGN1035 showed superior antitumor effects in ovarian cancer models compared with either monotherapy. In the A2780 model, REGN1035 (targets murine Dll4) or REGN421 (targets human Dll4) reduced tumor weights by 62% and 82%, respectively; aflibercept alone reduced tumor weights by 90%. Greater therapeutic effects were observed for Dll4 blockade (REGN1035) combined with either aflibercept or docetaxel (P < 0.05 for the combination vs. aflibercept). The superior antitumor effects of REGN1035 and aflibercept were related to increased apoptosis in tumor cells compared with the monotherapy. We also found that GATA3 expression was significantly increased in tumor stroma from the mice treated with REGN1035 combined with docetaxel or aflibercept, suggesting an indirect effect of these combination treatments on the tumor stroma. These findings identify that dual targeting of Dll4 and VEGF is an attractive therapeutic approach. Mol Cancer Ther; 15(6); 1344-52. ©2016 AACR. PMID:27009216

  5. 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

  6. 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. PMID:25500545

  7. Sensitization of Pancreatic Cancers to Gemcitabine Chemoradiation by WEE1 Kinase Inhibition Depends on Homologous Recombination Repair12

    PubMed Central

    Kausar, Tasneem; Schreiber, Jason S.; Karnak, David; Parsels, Leslie A.; Parsels, Joshua D.; Davis, Mary A.; Zhao, Lili; Maybaum, Jonathan; Lawrence, Theodore S.; Morgan, Meredith A.

    2015-01-01

    To improve the efficacy of chemoradiation therapy for locally advanced pancreatic cancer and begin to establish patient selection criteria, we investigated the combination of the WEE1 inhibitor AZD1775 with gemcitabine-radiation in homologous recombination (HR) repair proficient and deficient pancreatic cancers. Sensitization to gemcitabine-radiation by AZD1775 was assessed in pancreatic cancer cells by clonogenic survival and in patient-derived xenografts by tumor growth. The contributions of HR repair inhibition and G2 checkpoint abrogation to sensitization were assessed by γH2AX, BRCA2 manipulation, and RAD51 focus formation and pHistone H3 flow cytometry, respectively. We found that AZD1775 sensitized to gemcitabine-radiation in BRCA2 wild-type but not BRCA2 mutant pancreatic cancer cells. In all cells, AZD1775 caused inhibition of CDK1 phosphorylation and G2 checkpoint abrogation. However, sensitization by AZD1775 was associated with persistent γH2AX and inhibition of RAD51 focus formation. In HR-proficient (BRCA2 wild-type) or -deficient (BRAC2 null) isogenic cells, AZD1775 sensitized to gemcitabine-radiation in BRCA2 wild-type, but not in BRCA2 null cells, despite significant G2 checkpoint abrogation. In patient-derived pancreatic tumor xenografts, AZD1775 significantly inhibited tumor growth and impaired RAD51 focus formation in response to gemcitabine-radiation. In conclusion, WEE1 inhibition by AZD1775 is an effective strategy for sensitizing pancreatic cancers to gemcitabine chemoradiation. Although this sensitization is accompanied by inhibition of CDK1 phosphorylation and G2 checkpoint abrogation, this mechanism is not sufficient for sensitization. Our findings demonstrate that sensitization to chemoradiation by WEE1 inhibition results from inhibition of HR repair and suggest that patient tumors without underlying HR defects would benefit most from this therapy. PMID:26585231

  8. Inhibition of apoptosis as a mechanism of tumor promotion.

    PubMed

    Wright, S C; Zhong, J; Larrick, J W

    1994-06-01

    Recent evidence supports the concept that tumor growth in vivo depends on evasion of normal homeostatic control mechanisms that operate through induction of cell death by apoptosis. This study tested the hypothesis that a common property shared by known or suspected tumor promoters is the ability to block the process of apoptosis. A total of 10 tumor promoters were tested and all were found to inhibit DNA fragmentation and cell death of 7 different cell lines triggered into apoptosis by diverse agents. Resistance to apoptosis could be induced rapidly (within 1 h) by treating with relatively high concentrations of promoters. However, low physiological concentrations of promoters could also induce complete resistance to apoptosis after prolonged exposure (5-15 days of culture). Like tumor promotion in vivo, promoter-induced resistance to apoptosis was reversible after culturing in the absence of promoter. These findings provide new insight into the mechanism of tumor promotion and suggest a novel in vitro screening assay to detect new tumor-promoting agents in the environment. PMID:8005393

  9. Netrin-4 delays colorectal cancer carcinomatosis by inhibiting tumor angiogenesis.

    PubMed

    Eveno, Clarisse; Broqueres-You, Dong; Feron, Jean-Guillaume; Rampanou, Aurore; Tijeras-Raballand, Annemilaï; Ropert, Stanislas; Leconte, Laurence; Levy, Bernard I; Pocard, Marc

    2011-04-01

    A close relationship between tumor angiogenesis, growth, and carcinomatosis has been observed. Netrin-4 (NT-4) has been shown to regulate angiogenic responses. We aimed to examine the effects of NT-4 on colon tumor angiogenesis, growth, and carcinomatosis. We showed that NT-4 was expressed in human colon cancer cells (LS174). A 20-fold increase in NT-4 expression was stably induced by NT-4 pcDNA in LS174 cells. In vivo, a Matrigel angiogenesis assay showed that NT-4 overexpression altered vascular endothelial growth factor (VEGF)/basic fibroblast growth factor-induced angiogenesis. In nude mice with LS174 xenografts, NT-4 overexpression inhibited tumor angiogenesis and growth. In addition, these NT-4-involved inhibitory effects were associated with decreased tumor cell proliferation and increased tumor cell apoptosis. Using an orthotopic peritoneal carcinomatosis model, we demonstrated that NT-4 overexpression decreased colorectal cancer carcinomatosis. Moreover, carcinomatosis-related ascites formation was significantly decreased in mice transplanted with NT-4 LS174 cells versus control LS174 cells. The antiangiogenic activity of NT-4 was probably mediated by binding to its receptor neogenin. Netrin-4 had a direct effect on neither in vitro apoptosis and proliferation of cultured LS174 cells nor the VEGF-induced acute increase in vascular permeability in vivo. We propose that NT-4 overexpression decreases tumor growth and carcinomatosis, probably via an antiangiogenic effect, underlying the potential therapeutic interest in NT-4 in the treatment of colorectal cancer growth and carcinomatosis. PMID:21406174

  10. 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.

  11. 2-Methoxycinnamaldehyde inhibits tumor angiogenesis by suppressing Tie2 activation.

    PubMed

    Yamakawa, Daishi; Kidoya, Hiroyasu; Sakimoto, Susumu; Jia, Weizhen; Takakura, Nobuyuki

    2011-11-11

    Blood vessels are mainly composed of intraluminal endothelial cells (ECs) and mural cells adhering to the ECs on their basal side. Immature blood vessels lacking mural cells are leaky; thus, the process of mural cell adhesion to ECs is indispensable for stability of the vessels during physiological angiogenesis. However, in the tumor microenvironment, although some blood vessels are well-matured, the majority is immature. Because mural cell adhesion to ECs also has a marked anti-apoptotic effect, angiogenesis inhibitors that destroy immature blood vessels may not affect mature vessels showing more resistance to apoptosis. Activation of Tie2 receptor tyrosine kinase expressed in ECs mediates pro-angiogenic effects via the induction of EC migration but also facilitates vessel maturation via the promotion of cell adhesion between mural cells and ECs. Therefore, inhibition of Tie2 has the advantage of completely inhibiting angiogenesis. Here, we isolated a novel small molecule Tie2 kinase inhibitor, identified as 2-methoxycinnamaldehyde (2-MCA). We found that 2-MCA inhibits both sprouting angiogenesis and maturation of blood vessels, resulting in inhibition of tumor growth. Our results suggest a potent clinical benefit of disrupting these two using Tie2 inhibitors. PMID:22033407

  12. Cognitive Screening in Brain Tumors: Short but Sensitive Enough?

    PubMed Central

    Robinson, Gail A.; Biggs, Vivien; Walker, David G.

    2015-01-01

    Cognitive deficits in brain tumors are generally thought to be relatively mild and non-specific, although recent evidence challenges this notion. One possibility is that cognitive screening tools are being used to assess cognitive functions but their sensitivity to detect cognitive impairment may be limited. For improved sensitivity to recognize mild and/or focal cognitive deficits in brain tumors, neuropsychological evaluation tailored to detect specific impairments has been thought crucial. This study investigates the sensitivity of a cognitive screening tool, the Montreal Cognitive Assessment (MoCA), compared to a brief but tailored cognitive assessment (CA) for identifying cognitive deficits in an unselected primary brain tumor sample (i.e., low/high-grade gliomas, meningiomas). Performance is compared on broad measures of impairment: (a) number of patients impaired on the global screening measure or in any cognitive domain; and (b) number of cognitive domains impaired and specific analyses of MoCA-Intact and MoCA-Impaired patients on specific cognitive tests. The MoCA-Impaired group obtained lower naming and word fluency scores than the MoCA-Intact group, but otherwise performed comparably on cognitive tests. Overall, based on our results from patients with brain tumor, the MoCA has extremely poor sensitivity for detecting cognitive impairments and a brief but tailored CA is necessary. These findings will be discussed in relation to broader issues for clinical management and planning, as well as specific considerations for neuropsychological assessment of brain tumor patients. PMID:25815273

  13. 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

  14. 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.

  15. 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

    2015-01-01

    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

  16. Inhibition of PARP-1 by olaparib (AZD2281) increases the radiosensitivity of a lung tumor xenograft.

    PubMed

    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

    2011-10-01

    PARP-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, although 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 hemodynamics in non-small cell lung carcinoma (NSCLC). In irradiated Calu-6 and A549 cells, olaparib enhanced the cytotoxic effects of radiation (sensitizer enhancement ratio at 10% survival = 1.5 and 1.3) and DNA double-strand breaks persisted for at least 24 hours 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 radiosensitization was solely due 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 preconstricted 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

  17. Compromised GABAergic inhibition contributes to tumor-associated epilepsy.

    PubMed

    MacKenzie, Georgina; O'Toole, Kate K; Moss, Stephen J; Maguire, Jamie

    2016-10-01

    Glioblastoma Multiforme (GBM) is the most common form of primary brain tumor with 30-50% of patients presenting with epilepsy. These tumor-associated seizures are often resistant to traditional antiepileptic drug treatment and persist after tumor resection. This suggests that changes in the peritumoral tissue underpin epileptogenesis. It is known that glioma cells extrude pathological concentrations of glutamate which is thought to play a role in tumor progression and the development of epilepsy. Given that pathological concentrations of glutamate have been shown to dephosphorylate and downregulate the potassium chloride cotransporter KCC2, we hypothesized that glioma-induced alterations in KCC2 in the peritumoral region may play a role in tumor-associated epilepsy. Consistent with this hypothesis, we observe a decrease in total KCC2 expression and a dephosphorylation of KCC2 at residue Ser940 in a glioma model which exhibits hyperexcitability and the development of spontaneous seizures. To determine whether the reduction of KCC2 could potentially contribute to tumor-associated epilepsy, we generated mice with a focal knockdown of KCC2 by injecting AAV2-Cre-GFP into the cortex of floxed KCC2 mice. The AAV2-Cre-mediated knockdown of KCC2 was sufficient to induce the development of spontaneous seizures. Further, blocking NKCC1 with bumetanide to offset the loss of KCC2 reduced the seizure susceptibility in glioma-implanted mice. These findings support a mechanism of tumor-associated epilepsy involving downregulation of KCC2 in the peritumoral region leading to compromised GABAergic inhibition and suggest that modulating chloride homeostasis may be useful for seizure control. PMID:27513374

  18. Methylthioadenosine (MTA) inhibits melanoma cell proliferation and in vivo tumor growth

    PubMed Central

    2010-01-01

    Background Melanoma is the most deadly form of skin cancer without effective treatment. Methylthioadenosine (MTA) is a naturally occurring nucleoside with differential effects on normal and transformed cells. MTA has been widely demonstrated to promote anti-proliferative and pro-apoptotic responses in different cell types. In this study we have assessed the therapeutic potential of MTA in melanoma treatment. Methods To investigate the therapeutic potential of MTA we performed in vitro proliferation and viability assays using six different mouse and human melanoma cell lines wild type for RAS and BRAF or harboring different mutations in RAS pathway. We also have tested its therapeutic capabilities in vivo in a xenograft mouse melanoma model and using variety of molecular techniques and tissue culture we investigated its anti-proliferative and pro-apoptotic properties. Results In vitro experiments showed that MTA treatment inhibited melanoma cell proliferation and viability in a dose dependent manner, where BRAF mutant melanoma cell lines appear to be more sensitive. Importantly, MTA was effective inhibiting in vivo tumor growth. The molecular analysis of tumor samples and in vitro experiments indicated that MTA induces cytostatic rather than pro-apoptotic effects inhibiting the phosphorylation of Akt and S6 ribosomal protein and inducing the down-regulation of cyclin D1. Conclusions MTA inhibits melanoma cell proliferation and in vivo tumor growth particularly in BRAF mutant melanoma cells. These data reveal a naturally occurring drug potentially useful for melanoma treatment. PMID:20529342

  19. Tumoral expression of IL-33 inhibits tumor growth and modifies the tumor microenvironment through CD8+ T and NK cells.

    PubMed

    Gao, Xin; Wang, Xuefeng; Yang, Qianting; Zhao, Xin; Wen, Wen; Li, Gang; Lu, Junfeng; Qin, Wenxin; Qi, Yuan; Xie, Fang; Jiang, Jingting; Wu, Changping; Zhang, Xueguang; Chen, Xinchun; Turnquist, Heth; Zhu, Yibei; Lu, Binfeng

    2015-01-01

    Cancer immunotherapy has shown great promise as a new standard cancer therapeutic modality. However, the response rates are limited for current approach that depends on enhancing spontaneous antitumor immune responses. Therefore, increasing tumor immunogenicity by expressing appropriate cytokines should further improve the current immunotherapy. IL-33 is a member of the IL-1 family of cytokines and is released by necrotic epithelial cells or activated innate immune cells and is thus considered a "danger" signal. The role of IL-33 in promoting type 2 immune responses and tissue inflammation has been well established. However, whether IL-33 drives antitumor immune responses is controversial. Our previous work established that IL-33 promoted the function of CD8(+) T cells. In this study, we showed that the expression of IL-33 in two types of cancer cells potently inhibited tumor growth and metastasis. Mechanistically, IL-33 increased numbers and IFN-γ production by CD8(+) T and NK cells in tumor tissues, thereby inducing a tumor microenvironment favoring tumor eradication. Importantly, IL-33 greatly increased tumor Ag-specific CD8(+) T cells. Furthermore, both NK and CD8(+) T cells were required for the antitumor effect of IL-33. Moreover, depletion of regulatory T cells worked synergistically with IL-33 expression for tumor elimination. Our studies established "alarmin" IL-33 as a promising new cytokine for tumor immunotherapy through promoting cancer-eradicating type 1 immune responses. PMID:25429071

  20. Tumoral expression of IL-33 inhibits tumor growth and modifies the tumor microenvironment through CD8+ T and NK cells

    PubMed Central

    Gao, Xin; Wang, Xuefeng; Yang, Qianting; Zhao, Xin; Wen, Wen; Li, Gang; Lu, Junfeng; Qin, Wenxin; Qi, Yuan; Xie, Fang; Jiang, Jingting; Wu, Changping; Zhang, Xueguang; Chen, Xinchun; Turnquist, Heth; Zhu, Yibei; Lu, Binfeng

    2014-01-01

    Cancer immunotherapy has shown great promise as a new standard cancer therapeutic modality. However, the response rates are limited for current approach that depends on enhancing spontaneous antitumor immune responses. Therefore, increasing tumor immunogenicity by expressing appropriate cytokines should further improve the current immunotherapy. Interleukin-33 is a member of the IL-1 family of cytokines and is released by necrotic epithelial cells or activated innate immune cells and is thus considered a “danger” signal. The role of IL-33 in promoting type 2 immune responses and tissue inflammation has been well established. However, whether IL-33 drives antitumor immune responses is controversial. Our previous work established that IL-33 promoted the function of CD8+ T cells. Here, we showed that the expression of IL-33 in two types of cancer cells potently inhibited tumor growth and metastasis. Mechanistically, IL-33 increased numbers and IFNγ production by CD8+ T and NK cells in tumor tissues, thereby inducing a tumor microenvironment favoring tumor eradication. Importantly, IL-33 greatly increased tumor-antigen-specific CD8+ T cells. Furthermore, both NK and CD8+ T cells were required for the antitumor effect of IL-33. Moreover, depletion of regulatory T cells (Treg) worked synergistically with IL-33 expression for tumor elimination. Our studies established “alarmin” IL-33 as a promising new cytokine for tumor immunotherapy through promoting cancer-eradicating type 1 immune responses. PMID:25429071

  1. 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.

  2. RALBP1/RLIP76 depletion in mice suppresses tumor growth by inhibiting tumor neovascularization

    PubMed Central

    Lee, Seunghyung; Wurtzel, Jeremy G.T.; Singhal, Sharad S.; Awasthi, Sanjay; Goldfinger, Lawrence E.

    2012-01-01

    RalBP1/RLIP76 is a widely expressed multifunctional protein that binds the Ral and R-Ras small GTPases. In the mouse, RLIP76 is non-essential but its depletion or blockade promotes tumorigenesis and heightens the sensitivity of normal and tumor cells to radiation and cytotoxic drugs. However, its pathobiological functions which support tumorigenesis are not well understood. Here we show that RLIP76 is required for angiogenesis and for efficient neovascularization of primary solid tumors. Tumor growth from implanted melanoma or carcinoma cells was blunted in RLIP76−/− mice. An X-ray microCT-based method to model tumor vascular structures revealed defects in both the extent and form of tumor angiogenesis in RLIP76−/− mice. Specifically, tumor vascular volumes were diminished and vessels were fewer in number, shorter, and narrower in RLIP76−/− mice than in wild-type mice. Moreover, we found that angiogenesis was blunted in mutant mice in the absence of tumor cells, with endothelial cells isolated from these animals exhibiting defects in migration, proliferation and cord formation in vitro. Taken together, our results establish that RLIP76 is required for efficient endothelial cell function and angiogenesis in solid tumors. PMID:22902412

  3. 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

  4. Tetraploidization increases sensitivity to Aurora B kinase inhibition.

    PubMed

    Marxer, Miriam; Foucar, Charles E; Man, Wing Yu; Chen, Yu; Ma, Hoi Tang; Poon, Randy Y C

    2012-07-01

    Aurora kinases are overexpressed in many cancers and are targets for anticancer drugs. The yeast homolog of Aurora B kinase, IPL1, was found to be a ploidy-specific lethality gene. Given that polyploidization is a common feature of many cancers, we hypothesized polyploidization also sensitizes mammalian cells to inhibition of Aurora kinases. Using two models of apparent diploid vs. tetraploid cell lines (one based on the hepatocellular carcinoma cell line Hep3B and another on untransformed mouse fibroblasts), we found that tetraploid cells were more sensitive to Aurora B inhibition than their diploid counterparts. Apoptosis could be induced in tetraploid cells by two different Aurora B inhibitors. Furthermore, tetraploid cells were sensitive to Aurora B inhibition but were not affected by Aurora A inhibition. Interestingly, the underlying mechanism was due to mitotic slippage and the subsequent excessive genome reduplication. In support of this, abolition of cytokinesis with dihydrocytochalasin B resulted in similar effects on tetraploid cells as Aurora B inhibition. These results indicate that inhibition of Aurora B or cytokinesis can promote apoptosis effectively in polyploid cancer cells. PMID:22722494

  5. Decorin: A Growth Factor Antagonist for Tumor Growth Inhibition

    PubMed Central

    Järvinen, Tero A. H.; Prince, Stuart

    2015-01-01

    Decorin (DCN) is the best characterized member of the extracellular small leucine-rich proteoglycan family present in connective tissues, typically in association with or “decorating” collagen fibrils. It has substantial interest to clinical medicine owing to its antifibrotic, anti-inflammatory, and anticancer effects. Studies on DCN knockout mice have established that a lack of DCN is permissive for tumor development and it is regarded as a tumor suppressor gene. A reduced expression or a total disappearance of DCN has been reported to take place in various forms of human cancers during tumor progression. Furthermore, when used as a therapeutic molecule, DCN has been shown to inhibit tumor progression and metastases in experimental cancer models. DCN affects the biology of various types of cancer by targeting a number of crucial signaling molecules involved in cell growth, survival, metastasis, and angiogenesis. The active sites for the neutralization of different growth factors all reside in different parts of the DCN molecule. An emerging concept that multiple proteases, especially those produced by inflammatory cells, are capable of cleaving DCN suggests that native DCN could be inactivated in a number of pathological inflammatory conditions. In this paper, we review the role of DCN in cancer. PMID:26697491

  6. 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

  7. Resveratrol-loaded nanocapsules inhibit murine melanoma tumor growth.

    PubMed

    Carletto, Bruna; Berton, Juliana; Ferreira, Tamara Nascimento; Dalmolin, Luciana Facco; Paludo, Katia Sabrina; Mainardes, Rubiana Mara; Farago, Paulo Vitor; Favero, Giovani Marino

    2016-08-01

    In this study, resveratrol-loaded nanocapsules were developed and its antitumor activity tested on a melanoma mice model. These nanocapsules were spherically-shaped and presented suitable size, negative charge and high encapsulation efficiency for their use as a modified-release system of resveratrol. Nanoencapsulation leads to the drug amorphization. Resveratrol-loaded nanoparticles reduced cell viability of murine melanoma cells. There was a decrease in tumor volume, an increase in the necrotic area and inflammatory infiltrate of melanoma when resveratrol-loaded nanocapsules were compared to free resveratrol in treated mice. Nanoencapsulation of resveratrol also prevented metastasis and pulmonary hemorrhage. This modified-release technology containing resveratrol can be used as a feasible approach in order to inhibit murine melanoma tumor growth. PMID:27070053

  8. Restoration of XAF1 expression induces apoptosis and inhibits tumor growth in gastric cancer.

    PubMed

    Tu, Shui Ping; Liston, Peter; Cui, Jian Tao; Lin, Marie C M; Jiang, Xiao Hua; Yang, Yi; Gu, Qing; Jiang, Shi Hu; Lum, Ching Tung; Kung, Hsiang Fu; Korneluk, Robert G; Wong, Benjamin Chun-Yu

    2009-08-01

    XAF1 (XIAP-associated factor 1) is a novel XIAP binding protein that can antagonize XIAP and sensitize cells to other cell death triggers. Our previous results have shown that aberrant hypermethylation of the CpG sites in XAF1 promoter is strongly associated with lower expression of XAF1 in gastric cancers. In our study, we investigated the effect of restoration of XAF1 expression on growth of gastric cancers. We found that the restoration of XAF1 expression suppressed anchorage-dependent and -independent growth and increased sensitivity to TRAIL and drug-induced apoptosis. Stable cell clones expressing XAF1 exhibited delayed tumor initiation in nude mice. Restoration of XAF1 expression mediated by adenovirus vector greatly increased apoptosis in gastric cancer cell lines in a time- and dose-dependent manner and sensitized cancer cells to TRAIL and drugs-induced apoptosis. Adeno-XAF1 transduction induced cell cycle G2/M arrest and upregulated the expression of p21 and downregulated the expression of cyclin B1 and cdc2. Notably, adeno-XAF1 treatment significantly inhibited tumor growth, strongly enhanced the antitumor activity of TRAIL in a gastric cancer xenograft model in vivo, and significantly prolonged the survival time of animals bearing tumor xenografts. Complete eradication of established tumors was achieved on combined treatment with adeno-XAF1 and TRAIL. Our results document that the restoration of XAF1 inhibits gastric tumorigenesis and tumor growth and that XAF1 is a promising candidate for cancer gene therapy. PMID:19358264

  9. 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. PMID:27196770

  10. 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. PMID:26803407

  11. Casiopeina II-gly and bromo-pyruvate inhibition of tumor hexokinase, glycolysis, and oxidative phosphorylation.

    PubMed

    Marín-Hernández, Alvaro; Gallardo-Pérez, Juan Carlos; López-Ramírez, Sayra Y; García-García, Jorge Donato; Rodríguez-Zavala, José Salud; Ruiz-Ramírez, Lena; Gracia-Mora, Isabel; Zentella-Dehesa, Alejandro; Sosa-Garrocho, Marcela; Macías-Silva, Marina; Moreno-Sánchez, Rafael; Rodríguez-Enríquez, Sara

    2012-05-01

    The copper-based drug Casiopeina II-gly (CasII-gly) shows potent antineoplastic effect and diminishes mitochondrial metabolism on several human and rodent malignant tumors. To elucidate whether CasII-gly also affects glycolysis, (a) the flux through the complete pathway and the initial segment and (b) the activities of several glycolytic enzymes of AS-30D hepatocarcinoma cells were determined. CasII-gly (IC₅₀ = 0.74-6.7 μM) was more effective to inhibit 24-72 h growth of several human carcinomas than 3-bromopyruvate (3BrPyr) (IC₅₀ = 45-100 μM) with no apparent effect on normal human-proliferating lymphocytes and HUVECs. In short-term 60-min experiments, CasII-gly increased tumor cell lactate production and glycogen breakdown. CasII-gly was 1.3-21 times more potent than 3BrPyr and cisplatin to inhibit tumor HK. As CasII-gly inhibited the soluble and mitochondrial HK activities and the flux through the HK-TPI glycolytic segment, whereas PFK-1, GAPDH, PGK, PYK activities and HPI-TPI segment flux were not affected, the data suggested glycogenolysis activation induced by HK inhibition. Accordingly, glycogen-depleted as well as oligomycin-treated cancer cells became more sensitive to CasII-gly. The inhibition time-course of HK by CasII-gly was slower than that of OxPhos in AS-30D cells, indicating that glycolytic toxicity was secondary to mitochondria, the primary CasII-gly target. In long-term 24-h experiments with HeLa cells, 5 μM CasII-gly inhibited OxPhos (80%), glycolysis (40%), and HK (42%). The present data indicated that CasII-gly is an effective multisite anticancer drug simultaneously targeting mitochondria and glycolysis. PMID:22349057

  12. 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

  13. The c-Met Inhibitor MSC2156119J Effectively Inhibits Tumor Growth in Liver Cancer Models.

    PubMed

    Bladt, Friedhelm; Friese-Hamim, Manja; Ihling, Christian; Wilm, Claudia; Blaukat, Andree

    2014-01-01

    The mesenchymal-epithelial transition factor (c-Met) is a receptor tyrosine kinase with hepatocyte growth factor (HGF) as its only high-affinity ligand. Aberrant activation of c-Met is associated with many human malignancies, including hepatocellular carcinoma (HCC). We investigated the in vivo antitumor and antimetastatic efficacy of the c-Met inhibitor MSC2156119J (EMD 1214063) in patient-derived tumor explants. BALB/c nude mice were inoculated with MHCC97H cells or with tumor fragments of 10 patient-derived primary liver cancer explants selected according to c-Met/HGF expression levels. MSC2156119J (10, 30, and 100 mg/kg) and sorafenib (50 mg/kg) were administered orally as single-agent treatment or in combination, with vehicle as control. Tumor response, metastases formation, and alpha fetoprotein (AFP) levels were measured. MSC2156119J inhibited tumor growth and induced complete regression in mice bearing subcutaneous and orthotopic MHCC97H tumors. AFP levels were undetectable after 5 weeks of MSC2156119J treatment, and the number of metastatic lung foci was reduced. Primary liver explant models with strong c-Met/HGF activation showed increased responsiveness to MSC2156119J, with MSC2156119J showing similar or superior activity to sorafenib. Tumors characterized by low c-Met expression were less sensitive to MSC2156119J. MSC2156119J was better tolerated than sorafenib, and combination therapy did not improve efficacy. These findings indicate that selective c-Met/HGF inhibition with MSC2156119J is associated with marked regression of c-Met high-expressing tumors, supporting its clinical development as an antitumor treatment for HCC patients with active c-Met signaling. PMID:25256830

  14. HDAC6 inhibition restores ciliary expression and decreases tumor growth

    PubMed Central

    Gradilone, Sergio A; Radtke, Brynn N; Bogert, Pamela S; Huang, Bing Q; Gajdos, Gabriella B; LaRusso, Nicholas F

    2013-01-01

    Primary cilia are multisensory organelles recently found to be absent in some tumor cells, but the mechanisms of deciliation and the role of cilia in tumor biology remain unclear. Cholangiocytes, the epithelial cells lining the biliary tree, normally express primary cilia and their interaction with bile components regulates multiple processes, including proliferation and transport. Utilizing cholangiocarcinoma (CCA) as a model, we found primary cilia are reduced in CCA by a mechanism involving histone deacetylase 6 (HDAC6). The experimental deciliation of normal cholangiocyte cells increased the proliferation rate and induced anchorage-independent growth. Furthermore, deciliation induced the activation of MAPK and Hedgehog signaling, two important pathways involved in CCA development. We found HDAC6 is overexpressed in CCA and overexpression of HDAC6 in normal cholangiocytes induced deciliation, and increased both proliferation and anchorage-independent growth. To evaluate the effect of cilia restoration on tumor cells, we targeted HDAC6 by shRNA or by the pharmacologic inhibitor, tubastatin-A. Both approaches restored the expression of primary cilia in CCA cell lines and decreased cell proliferation and anchorage-independent growth. The effects of tubastatin-A were abolished when CCA cells were rendered unable to regenerate cilia by stable transfection of IFT88-shRNA. Finally, inhibition of HDAC6 by tubastatin-A also induced a significant decrease in tumor growth in a CCA animal model. Our data support a key role for primary cilia in malignant transformation, provide a plausible mechanism for their involvement, and suggest that restoration of primary cilia in tumor cells by HDAC6 targeting may be a potential therapeutic approach for CCA. PMID:23370327

  15. 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.

  16. XPO1 Inhibition Preferentially Disrupts the 3D Nuclear Organization of Telomeres in Tumor Cells.

    PubMed

    Taylor-Kashton, Cheryl; Lichtensztejn, Daniel; Baloglu, Erkan; Senapedis, William; Shacham, Sharon; Kauffman, Michael G; Kotb, Rami; Mai, Sabine

    2016-12-01

    Previous work has shown that the three-dimensional (3D) nuclear organization of telomeres is altered in cancer cells and the degree of alterations coincides with aggressiveness of disease. Nuclear pores are essential for spatial genome organization and gene regulation and XPO1 (exportin 1/CRM1) is the key nuclear export protein. The Selective Inhibitor of Nuclear Export (SINE) compounds developed by Karyopharm Therapeutics (KPT-185, KPT-330/selinexor, and KPT-8602) inhibit XPO1 nuclear export function. In this study, we investigated whether XPO1 inhibition has downstream effects on the 3D nuclear organization of the genome. This was assessed by measuring the 3D telomeric architecture of normal and tumor cells in vitro and ex vivo. Our data demonstrate for the first time a rapid and preferential disruption of the 3D nuclear organization of telomeres in tumor cell lines and in primary cells ex vivo derived from treatment-naïve newly diagnosed multiple myeloma patients. Normal primary cells in culture as well as healthy lymphocyte control cells from the same patients were minimally affected. Using both lymphoid and non-lymphoid tumor cell lines, we found that the downstream effects on the 3D nuclear telomere structure are independent of tumor type. We conclude that the 3D nuclear organization of telomeres is a sensitive indicator of cellular response when treated with XPO1 inhibitors. J. Cell. Physiol. 231: 2711-2719, 2016. © 2016 Wiley Periodicals, Inc. PMID:26991404

  17. Effects of pluronic and doxorubicin on drug uptake, cellular metabolism, apoptosis and tumor inhibition in animal models of MDR cancers.

    PubMed

    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

    2010-05-10

    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

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

    PubMed Central

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

    2015-01-01

    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. PMID:26439804

  19. 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. PMID:26439804

  20. RPA inhibition increases replication stress and suppresses tumor growth.

    PubMed

    Glanzer, Jason G; Liu, Shengqin; Wang, Ling; Mosel, Adam; Peng, Aimin; Oakley, Greg G

    2014-09-15

    The ATR/Chk1 pathway is a critical surveillance network that maintains genomic integrity during DNA replication by stabilizing the replication forks during normal replication to avoid replication stress. One of the many differences between normal cells and cancer cells is the amount of replication stress that occurs during replication. Cancer cells with activated oncogenes generate increased levels of replication stress. This creates an increased dependency on the ATR/Chk1 pathway in cancer cells and opens up an opportunity to preferentially kill cancer cells by inhibiting this pathway. In support of this idea, we have identified a small molecule termed HAMNO ((1Z)-1-[(2-hydroxyanilino)methylidene]naphthalen-2-one), a novel protein interaction inhibitor of replication protein A (RPA), a protein involved in the ATR/Chk1 pathway. HAMNO selectively binds the N-terminal domain of RPA70, effectively inhibiting critical RPA protein interactions that rely on this domain. HAMNO inhibits both ATR autophosphorylation and phosphorylation of RPA32 Ser33 by ATR. By itself, HAMNO treatment creates DNA replication stress in cancer cells that are already experiencing replication stress, but not in normal cells, and it acts synergistically with etoposide to kill cancer cells in vitro and slow tumor growth in vivo. Thus, HAMNO illustrates how RPA inhibitors represent candidate therapeutics for cancer treatment, providing disease selectivity in cancer cells by targeting their differential response to replication stress. Cancer Res; 74(18); 5165-72. ©2014 AACR. PMID:25070753

  1. RPA Inhibition increases Replication Stress and Suppresses Tumor Growth

    PubMed Central

    Glanzer, Jason G.; Liu, Shengqin; Wang, Ling; Mosel, Adam; Peng, Aimin; Oakley, Greg G.

    2014-01-01

    The ATR/Chk1 pathway is a critical surveillance network that maintains genomic integrity during DNA replication by stabilizing the replication forks during normal replication to avoid replication stress. One of the many differences between normal cells and cancer cells is the amount of replication stress that occurs during replication. Cancer cells with activated oncogenes generate increased levels of replication stress. This creates an increased dependency on the ATR/Chk1 pathway in cancer cells and opens up an opportunity to preferentially kill cancer cells by inhibiting this pathway. In support of this idea, we have identified a small molecule termed HAMNO ((1Z)-1-[(2-hydroxyanilino)methylidene]naphthalen-2-one), a novel protein interaction inhibitor of replication protein A (RPA), a protein involved in the ATR/Chk1 pathway. HAMNO selectively binds the N-terminal domain of RPA70, effectively inhibiting critical RPA protein interactions which rely on this domain. HAMNO inhibits both ATR autophosphorylation and phosphorylation of RPA32 Ser33 by ATR. By itself, HAMNO treatment creates DNA replication stress in cancer cells that are already experiencing replication stress, but not in normal cells, and it acts synergistically with etoposide to kill cancer cells in vitro and slow tumor growth in vivo. Thus, HAMNO illustrates how RPA inhibitors represent candidate therapeutics for cancer treatment, providing disease selectivity in cancer cells by targeting their differential response to replication stress. PMID:25070753

  2. Arsenic trioxide inhibits tumor cell growth in malignant rhabdoid tumors in vitro and in vivo by targeting overexpressed Gli1.

    PubMed

    Kerl, Kornelius; Moreno, Natalia; Holsten, Till; Ahlfeld, Julia; Mertins, Julius; Hotfilder, Marc; Kool, Marcel; Bartelheim, Kerstin; Schleicher, Sabine; Handgretinger, Rupert; Schüller, Ulrich; Meisterernst, Michael; Frühwald, Michael C

    2014-08-15

    Rhabdoid tumors are highly aggressive tumors occurring in infants and very young children. Despite multimodal and intensive therapy prognosis remains poor. Molecular analyses have uncovered several deregulated pathways, among them the CDK4/6-Rb-, the WNT- and the Sonic hedgehog (SHH) pathways. The SHH pathway is activated in rhabdoid tumors by GLI1 overexpression. Here, we demonstrate that arsenic trioxide (ATO) inhibits tumor cell growth of malignant rhabdoid tumors in vitro and in a mouse xenograft model by suppressing Gli1. Our data uncover ATO as a promising therapeutic approach to improve prognosis for rhabdoid tumor patients. PMID:24420698

  3. Englerin A Agonizes the TRPC4/C5 Cation Channels to Inhibit Tumor Cell Line Proliferation

    PubMed Central

    Carson, Cheryl; Raman, Pichai; Tullai, Jennifer; Xu, Lei; Henault, Martin; Thomas, Emily; Yeola, Sarita; Lao, Jianmin; McPate, Mark; Verkuyl, J. Martin; Marsh, George; Sarber, Jason; Amaral, Adam; Bailey, Scott; Lubicka, Danuta; Pham, Helen; Miranda, Nicolette; Ding, Jian; Tang, Hai-Ming; Ju, Haisong; Tranter, Pamela; Ji, Nan; Krastel, Philipp; Jain, Rishi K.; Schumacher, Andrew M.; Loureiro, Joseph J.; George, Elizabeth; Berellini, Giuliano; Ross, Nathan T.; Bushell, Simon M.; Erdemli, Gül; Solomon, Jonathan M.

    2015-01-01

    Englerin A is a structurally unique natural product reported to selectively inhibit growth of renal cell carcinoma cell lines. A large scale phenotypic cell profiling experiment (CLiP) of englerin A on ¬over 500 well characterized cancer cell lines showed that englerin A inhibits growth of a subset of tumor cell lines from many lineages, not just renal cell carcinomas. Expression of the TRPC4 cation channel was the cell line feature that best correlated with sensitivity to englerin A, suggesting the hypothesis that TRPC4 is the efficacy target for englerin A. Genetic experiments demonstrate that TRPC4 expression is both necessary and sufficient for englerin A induced growth inhibition. Englerin A induces calcium influx and membrane depolarization in cells expressing high levels of TRPC4 or its close ortholog TRPC5. Electrophysiology experiments confirmed that englerin A is a TRPC4 agonist. Both the englerin A induced current and the englerin A induced growth inhibition can be blocked by the TRPC4/C5 inhibitor ML204. These experiments confirm that activation of TRPC4/C5 channels inhibits tumor cell line proliferation and confirms the TRPC4 target hypothesis generated by the cell line profiling. In selectivity assays englerin A weakly inhibits TRPA1, TRPV3/V4, and TRPM8 which suggests that englerin A may bind a common feature of TRP ion channels. In vivo experiments show that englerin A is lethal in rodents near doses needed to activate the TRPC4 channel. This toxicity suggests that englerin A itself is probably unsuitable for further drug development. However, since englerin A can be synthesized in the laboratory, it may be a useful chemical starting point to identify novel modulators of other TRP family channels. PMID:26098886

  4. Disruption of the protein interaction between FAK and IGF-1R inhibits melanoma tumor growth.

    PubMed

    Ucar, Deniz A; Kurenova, Elena; Garrett, Timothy J; Cance, William G; Nyberg, Carl; Cox, Audrey; Massoll, Nicole; Ostrov, David A; Lawrence, Nicholas; Sebti, Said M; Zajac-Kaye, Maria; Hochwald, Steven N

    2012-09-01

    FAK (focal adhesion kinase) and IGF-1R (insulin-like growth factor receptor-1) directly interact with each other and thereby activate crucial signaling pathways that benefit cancer cells. Inhibition of FAK and IGF-1R function has been shown to significantly decrease cancer cell proliferation and increase sensitivity to chemotherapy and radiation treatment. As a novel approach in human melanoma, we evaluated the effect of a small-molecule compound that disrupts the protein interaction of FAK and IGF-1R. Previously, using virtual screening and functional testing, we identified a lead compound (INT2-31) that targets the known FAK-IGF-1R protein interaction site. We studied the ability of this compound to disrupt FAK-IGF-1R protein interactions, inhibit downstream signaling, decrease human melanoma cell proliferation, alter cell cycle progression, induce apoptosis and decrease tumor growth in vivo. INT2-31 blocked the interaction of FAK and IGF-1R in vitro and in vivo in melanoma cells and tumor xenografts through precluding the activation of IRS-1, leading to reduced phosphorylation of AKT upon IGF-1 stimulation. As a result, INT2-31 significantly inhibited cell proliferation and viability (range 0.05-10 μM). More importantly, 15 mg/kg of INT2-31 given for 21 d via intraperitoneal injection disrupted the interaction of FAK and IGF-1R and effectively decreased phosphorylation of tumor AKT, resulting in significant melanoma tumor regression in vivo. Our data suggest that the FAK-IGF-1R protein interaction is an important target, and disruption of this interaction with a novel small molecule (INT2-31) has potential anti-neoplastic therapeutic effects in human melanoma. PMID:22894899

  5. Dual inhibition of cyclooxygenase-2 and soluble epoxide hydrolase synergistically suppresses primary tumor growth and metastasis

    PubMed Central

    Zhang, Guodong; Panigrahy, Dipak; Hwang, Sung Hee; Yang, Jun; Mahakian, Lisa M.; Wettersten, Hiromi I.; Liu, Jun-Yan; Wang, Yanru; Ingham, Elizabeth S.; Tam, Sarah; Kieran, Mark W.; Weiss, Robert H.; Ferrara, Katherine W.; Hammock, Bruce D.

    2014-01-01

    Prostaglandins derived from the cyclooxygenase (COX) pathway and epoxyeicosatrienoic acids (EETs) from the cytochrome P450/soluble epoxide hydrolase (sEH) pathway are important eicosanoids that regulate angiogenesis and tumorigenesis. COX-2 inhibitors, which block the formation of prostaglandins, suppress tumor growth, whereas sEH inhibitors, which increase endogenous EETs, stimulate primary tumor growth and metastasis. However, the functional interactions of these two pathways in cancer are unknown. Using pharmacological inhibitors as probes, we show here that dual inhibition of COX-2 and sEH synergistically inhibits primary tumor growth and metastasis by suppressing tumor angiogenesis. COX-2/sEH dual pharmacological inhibitors also potently suppress primary tumor growth and metastasis by inhibiting tumor angiogenesis via selective inhibition of endothelial cell proliferation. These results demonstrate a critical interaction of these two lipid metabolism pathways on tumorigenesis and suggest dual inhibition of COX-2 and sEH as a potential therapeutic strategy for cancer therapy. PMID:25024195

  6. 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

  7. 5α-reductase inhibition suppresses testosterone-induced initial regrowth of regressed xenograft prostate tumors in animal models.

    PubMed

    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; Wang, Zhou

    2013-07-01

    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. ATR inhibition preferentially targets homologous recombination-deficient tumor cells.

    PubMed

    Krajewska, M; Fehrmann, R S N; Schoonen, P M; Labib, S; de Vries, E G E; Franke, L; van Vugt, M A T M

    2015-06-01

    Homologous recombination (HR) is required for faithful repair of double-strand DNA breaks. Defects in HR repair cause severe genomic instability and challenge cellular viability. Paradoxically, various cancers are HR defective and have apparently acquired characteristics to survive genomic instability. We aimed to identify these characteristics to uncover therapeutic targets for HR-deficient cancers. Cytogenetic analysis of 1143 ovarian cancers showed that the degree of genomic instability was correlated to amplification of replication checkpoint genes ataxia telangiectasia and Rad3-related kinase (ATR) and CHEK1. To test whether genomic instability leads to increased reliance on replication checkpoint signaling, we inactivated Rad51 to model HR-related genomic instability. Rad51 inactivation caused defective HR repair and induced aberrant replication dynamics. Notably, inhibition of Rad51 led to increased ATR/checkpoint kinase-1 (Chk1)-mediated replication stress signaling. Importantly, inhibition of ATR or Chk1 preferentially killed HR-deficient cancer cells. Combined, our data show that defective HR caused by Rad51 inhibition results in differential sensitivity for ATR and Chk1 inhibitors, implicating replication checkpoint kinases as potential drug targets for HR-defective cancers. PMID:25174396

  9. Inhibition of the autophagy flux by gingerol enhances TRAIL-induced tumor cell death.

    PubMed

    Nazim, Uddin Md; Jeong, Jae-Kyo; Seol, Jae-Won; Hur, Jin; Eo, Seong-Kug; Lee, John-Hwa; Park, Sang-Youel

    2015-05-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a primary anticancer agent and a member of the tumor necrosis factor family that selectively induces apoptosis in various tumor cells, but not in normal cells. Gingerol is a major ginger component with anti-inflammatory and anti‑tumorigenic activities. Autophagy flux is the complete process of autophagy, in which the autophagosomes are lysed by lysosomes. The role of autophagy in cell death or cell survival is controversial. A549 adenocarcinoma cells are TRAIL-resistant. In the present study, we showed that treatment with TRAIL slightly induced cell death, but gingerol treatment enhanced the TRAIL-induced cell death in human lung cancer cells. The combination of gingerol and TRAIL increased accumulation of microtubule-associated protein light chain 3-II and p62, confirming the inhibited autophagy flux. Collectively, our results suggest that gingerol sensitizes human lung cancer cells to TRAIL-induced apoptosis by inhibiting the autophagy flux. PMID:25813697

  10. Adenosine influences myeloid cells to inhibit aeroallergen sensitization.

    PubMed

    Pei, Hong; Linden, Joel

    2016-05-15

    Agonists of adenosine A2A receptors (A2ARs) suppress the activation of most immune cells and reduce acute inflammatory responses. Asthma is characterized by sensitization in response to initial allergen exposure and by airway hyperreactivity in response to allergen rechallenge. We sought to determine if A2AR activation with CGS-21680 (CGS) is more effective when CGS is administered during sensitization or rechallenge. C57BL/6 wild-type mice and Adora2a(f/f)LysMCre(+/-) mice, which lack A2ARs on myeloid cells, were sensitized with intranasal ovalbumin (OVA) and LPS. Airway sensitization was characterized by a rapid increase in numbers of IL-6(+) and IL-12(+) macrophages and dendritic cells in lungs. A2AR activation with CGS (0.1 μg·kg(-1)·min(-1) sc) only during sensitization reduced numbers of IL-6(+) and IL-12(+) myeloid cells in the lungs and reversed the effects of OVA rechallenge to increase airway hyperresponsiveness to methacholine. CGS treatment during sensitization also reduced the expansion of lung T helper (Th1 and Th17) cells and increased expansion of regulatory T cells in response to OVA rechallenge. Most of the effects of CGS administered during sensitization were eliminated by myeloid-selective A2AR deletion. Administration of CGS only during OVA rechallenge failed to reduce airway hyperresponsiveness. We conclude that myeloid cells are key targets of adenosine during sensitization and indirectly modify T cell polarization. The results suggest that a clinically useful strategy might be to use A2AR agonists to inhibit sensitization to new aeroallergens. We speculate that adenosine production by macrophages engulfing bacteria contributes to the curious suppression of sensitization in response to early-life infections. PMID:27016586

  11. Exploiting Temporal Collateral Sensitivity in Tumor Clonal Evolution.

    PubMed

    Zhao, Boyang; Sedlak, Joseph C; Srinivas, Raja; Creixell, Pau; Pritchard, Justin R; Tidor, Bruce; Lauffenburger, Douglas A; Hemann, Michael T

    2016-03-24

    The prevailing approach to addressing secondary drug resistance in cancer focuses on treating the resistance mechanisms at relapse. However, the dynamic nature of clonal evolution, along with potential fitness costs and cost compensations, may present exploitable vulnerabilities-a notion that we term "temporal collateral sensitivity." Using a combined pharmacological screen and drug resistance selection approach in a murine model of Ph(+) acute lymphoblastic leukemia, we indeed find that temporal and/or persistent collateral sensitivity to non-classical BCR-ABL1 drugs arises in emergent tumor subpopulations during the evolution of resistance toward initial treatment with BCR-ABL1-targeted inhibitors. We determined the sensitization mechanism via genotypic, phenotypic, signaling, and binding measurements in combination with computational models and demonstrated significant overall survival extension in mice. Additional stochastic mathematical models and small-molecule screens extended our insights, indicating the value of focusing on evolutionary trajectories and pharmacological profiles to identify new strategies to treat dynamic tumor vulnerabilities. PMID:26924578

  12. Carbon Monoxide Expedites Metabolic Exhaustion to Inhibit Tumor Growth

    PubMed Central

    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

    2013-01-01

    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. PMID:24121491

  13. 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

  14. Diet and tumor LKB1 expression interact to determine sensitivity to anti-neoplastic effects of metformin in vivo.

    PubMed

    Algire, C; Amrein, L; Bazile, M; David, S; Zakikhani, M; Pollak, M

    2011-03-10

    Hypothesis-generating epidemiological research has suggested that cancer burden is reduced in diabetics treated with metformin and experimental work has raised questions regarding the role of direct adenosine monophosphate-activated protein kinase (AMPK)-mediated anti-neoplastic effects of metformin as compared with indirect effects attributable to reductions in circulating insulin levels in the host. We treated both tumor LKB1 expression and host diet as variables, and observed that metformin inhibited tumor growth and reduced insulin receptor activation in tumors of mice with diet-induced hyperinsulinemia, independent of tumor LKB1 expression. In the absence of hyperinsulinemia, metformin inhibited only the growth of tumors transfected with short hairpin RNA against LKB1, a finding attributable neither to an effect on host insulin level nor to activation of AMPK within the tumor. Further investigation in vitro showed that cells with reduced LKB1 expression are more sensitive to metformin-induced adenosine triphosphate depletion owing to impaired ability to activate LKB1-AMPK-dependent energy-conservation mechanisms. Thus, loss of function of LKB1 can accelerate proliferation in contexts where it functions as a tumor suppressor, but can also sensitize cells to metformin. These findings predict that any clinical utility of metformin or similar compounds in oncology will be restricted to subpopulations defined by host insulin levels and/or loss of function of LKB1. PMID:21102522

  15. Sensitizing Triple-Negative Breast Cancer to PI3K Inhibition by Cotargeting IGF1R.

    PubMed

    de Lint, Klaas; Poell, Jos B; Soueidan, Hayssam; Jastrzebski, Katarzyna; Vidal Rodriguez, Jordi; Lieftink, Cor; Wessels, Lodewyk F A; Beijersbergen, Roderick L

    2016-07-01

    Targeted therapies have proven invaluable in the treatment of breast cancer, as exemplified by tamoxifen treatment for hormone receptor-positive tumors and trastuzumab treatment for HER2-positive tumors. In contrast, a subset of breast cancer negative for these markers, triple-negative breast cancer (TNBC), has met limited success with pathway-targeted therapies. A large fraction of TNBCs depend on the PI3K pathway for proliferation and survival, but inhibition of PI3K alone generally has limited clinical benefit. We performed an RNAi-based genetic screen in a human TNBC cell line to identify kinases whose knockdown synergizes with the PI3K inhibitor GDC-0941 (pictilisib). We discovered that knockdown of insulin-like growth factor-1 receptor (IGF1R) expression potently increased sensitivity of these cells to GDC-0941. Pharmacologic inhibition of IGF1R using OSI-906 (linsitinib) showed a strong synergy with PI3K inhibition. Furthermore, we found that the combination of GDC-0941 and OSI-906 is synergistic in 8 lines from a panel of 18 TNBC cell lines. In these cell lines, inhibition of IGF1R further decreases the activity of downstream PI3K pathway components when PI3K is inhibited. Expression analysis of the panel of TNBC cell lines indicates that the expression levels of IGF2BP3 can be used as a potential predictor for sensitivity to the PI3K/IGF1R inhibitor combination. Our data show that combination therapy consisting of PI3K and IGF1R inhibitors could be beneficial in a subset of TNBCs. Mol Cancer Ther; 15(7); 1545-56. ©2016 AACR. PMID:27196766

  16. Pharmacological telomerase inhibition can sensitize drug-resistant and drug-sensitive cells to chemotherapeutic treatment.

    PubMed

    Ward, Ryan J; Autexier, Chantal

    2005-09-01

    Effective strategies to reverse or prevent chemotherapeutic resistance are required before cancer therapies can be curative. Telomerase is the ribonucleoprotein responsible for de novo synthesis and maintenance of telomeres, and its activity is predominantly observed in cancer cells. The telomerase enzyme has been successfully inhibited or inactivated to sensitize cells to cellular stresses; however, no studies have determined yet the effect of combining a pharmacological inhibitor of telomerase catalysis and traditional chemotherapeutics for the treatment of drug-sensitive or drug-resistant cancers. Here, we describe the effect of 2-[(E)-3-naphtalen-2-yl-but-2-enoylamino]-benzoic acid (BIBR1532), a small-molecule inhibitor of telomerase catalytic activity, on drug-resistant leukemia and breast cancer cells and their parental counterparts when treated in combination with chemotherapeutics. We observed that BIBR1532-treated cells show progressive telomere shortening, decreased proliferative capacity, and sensitization to chemotherapeutic treatment. These effects are telomere length-dependent, because cells insensitive to BIBR1532 or cells released from telomerase inhibition did not demonstrate changes in growth ability or drug sensitivity. Our novel observations suggest that pharmacological telomerase inhibition in combination therapy may be a valid strategy for the treatment of both drug-sensitive and drug-resistant cancers. PMID:15939802

  17. 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

  18. Modulation of behavioral sensitization to cocaine by NAALADase inhibition.

    PubMed

    Shippenberg, T S; Rea, W; Slusher, B S

    2000-11-01

    Sensitization to cocaine has been attributed to alterations in excitatory amino acid and dopamine neurotransmission in the mesolimbic system. The present study sought to determine whether inhibition of NAALADase, an enzyme that cleaves glutamate from the endogenous neuropeptide, N-acetyl-aspartyl-glutamate (NAAG), attenuates sensitization to the psychomotor stimulant effects of cocaine. Rats received daily injections of cocaine (20.0 mg/kg/day; i.p.) or saline for 5 days. Fifteen minutes prior to these injections they received an i.p. injection of the NAALADase inhibitor, 2-PMPA (50.0-100 mg/kg), or vehicle. Locomotor activity and stereotypy produced by a challenge dose of cocaine (15.0 mg/kg) were assessed 3 days later. Acute cocaine administration increased locomotor activity in control animals. In animals with a prior history of cocaine administration, the behavioral response to cocaine was significantly enhanced. In animals that had received 2-PMPA in combination with cocaine, the enhancement of cocaine-induced locomotor activity was attenuated. No alteration in cocaine-evoked activity was observed in animals that had received once daily injections of 2-PMPA, alone. Acute administration of 2-PMPA also did not modify saline-induced locomotor activity or activity produced by an acute cocaine challenge. These data demonstrate that NAALADase inhibition attenuates the development of sensitization to the locomotor-activating effects of cocaine. Furthermore, this action cannot be attributed to an antagonism of the acute effects of cocaine. PMID:11018790

  19. 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. PMID:20626462

  20. 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

  1. Tumor growth suppression by inhibiting both autophagy and STAT3 signaling in HNSCC

    PubMed Central

    Wang, Wei-Ming; Ma, Si-Rui; Liu, Jian-Feng; Deng, Wei-Wei; Mao, Liang; Yu, Guang-Tao; Huang, Cong-Fa; Liu, Bing; Zhang, Wen-Feng; Sun, Zhi-Jun

    2015-01-01

    Autophagy is considered as a double-edged sword. It can prolong the survival of cancer cells and enhance its resistance to apoptosis, and paradoxically, defective autophagy has been linked to increased tumorigenesis, but the mechanism behind this phenomenon is unclear. In this study, we demonstrated that decreased phosphorylation of signal transducer and activator of transcription 3 (p-STAT3) was correlated with increased autophagy through the Akt/mTOR and Erk signaling pathways in human head and neck squamous cell carcinoma (HNSCC). We also showed that blockage of STAT3 by NSC74859 could markedly induce apoptotic cell death and autophagy. Meanwhile, increased autophagy inhibited apoptosis. The pharmacological or genetic inhibition of autophagy and STAT3 further sensitized HNSCC cells to apoptosis. Furthermore, evidence from xenograft model proved that suppressed STAT3 activity combined with inhibition of autophagy promoted tumor regression better than either treatment alone. Taken together, this present study demonstrated that autophagy alleviates apoptotic cell death in HNSCC, and combination of inhibition of STAT3 by NSC74859 and autophagy might be a promising new therapeutic strategy for HNSCC. PMID:26561201

  2. Mesenchymal stromal cells inhibit murine syngeneic anti-tumor immune responses by attenuating inflammation and reorganizing the tumor microenvironment.

    PubMed

    Modiano, Jaime F; Lindborg, Beth A; McElmurry, Ron T; Lewellen, Mitzi; Forster, Colleen L; Zamora, Edward A; Schaack, Jerome; Bellgrau, Donald; O'Brien, Timothy D; Tolar, Jakub

    2015-11-01

    The potential of mesenchymal stromal cells (MSCs) to inhibit anti-tumor immunity is becoming increasingly well recognized, but the precise steps affected by these cells during the development of an anti-tumor immune response remain incompletely understood. Here, we examined how MSCs affect the steps required to mount an effective anti-tumor immune response following administration of adenovirus Fas ligand (Ad-FasL) in the Lewis lung carcinoma (LL3) model. Administration of bone marrow-derived MSCs with LL3 cells accelerated tumor growth significantly. MSCs inhibited the inflammation induced by Ad-FasL in the primary tumors, precluding their rejection; MSCs also reduced the consequent expansion of tumor-specific T cells in the treated hosts. When immune T cells were transferred to adoptive recipients, MSCs impaired, but did not completely abrogate the ability of these T cells to promote elimination of secondary tumors. This impairment was associated with a modest reduction in tumor-infiltrating T cells, with a significant reduction in tumor-infiltrating macrophages, and with a reorganization of the stromal environment. Our data indicate that MSCs in the tumor environment reduce the efficacy of immunotherapy by creating a functional and anatomic barrier that impairs inflammation, T cell priming and expansion, and T cell function-including recruitment of effector cells. PMID:26250807

  3. Knockdown of retinoblastoma protein may sensitize glioma cells to cisplatin through inhibition of autophagy.

    PubMed

    Liu, Xiangyu; Sun, Kangjian; Wang, Handong; Dai, Yuyuan

    2016-05-01

    Glioblastoma multiforme (GBM) is one of the deadliest forms of cancer due to its limited sensitivity to chemotherapy and radiotherapy. Cisplatin (CCDP) is a widely used chemotherapeutic agent for tumors, but the agent often results in the development of chemo-resistance. In several cancers, cisplatin resistance is associated with autophagy induction. Here, we found that in glioma cells cisplatin treatment induced autophagy. Our data indicates that the autophagy induction plays a critical role in cisplatin resistance of glioma cells, knockdown of RB inhibited autophagy induced by cisplatin, and inhibition of autophagy improved cisplatin-induced apoptosis. It suggests that a combination of autophagy inhibitors with cisplatin may improve the therapeutic efficiency of cisplatin towards GBM with acquired resistance. PMID:27048711

  4. Re-sensitization of radiation resistant colorectal cancer cells to radiation through inhibition of AMPK pathway

    PubMed Central

    JIN, HONGYONG; GAO, SUJIE; GUO, HUILING; REN, SHENGNAN; JI, FUJIAN; LIU, ZHUO; CHEN, XUEBO

    2016-01-01

    Radiotherapy (RT) is commonly used to treat multi-tumors to attenuate the risk of recurrence. Despite impressive initial clinical responses, a large proportion of patients experience resistance to RT. Therefore, identification of functionally relevant biomarkers would be beneficial for radioresistant patients. Adenosine monophosphate-activated kinase (AMPK) is recognized as a mediator of tumor suppressor gene function. In the present study, radio-sensitive and -resistant colon cancer patient samples were compared and the AMPK pathway was observed to be highly activated in radioresistant patients. In addition, the protein and mRNA levels of AMPK were upregulated in radioresistant colon cancer cells in comparison to radiosensitive colon cancer cells. The present study provides evidence that activation of AMPK by metformin contributes to radioresistance. Inhibition of AMPK by either small interfering RNA or Compound C, which is a specific inhibitor of AMPK, re-sensitized radiation resistant cells. The data presented indicates a synergistic effect on radiation resistant cancer cells by the combination of Compound C and radiation. In summary, the present study proposes that inhibition of the AMPK pathway is a potential strategy for reversing radiation resistance and may contribute to the development of therapeutic anticancer drugs. PMID:27123089

  5. The RAF inhibitor PLX4032 inhibits ERK signaling and tumor cell proliferation in a V600E BRAF-selective manner

    PubMed Central

    Joseph, Eric W.; Pratilas, Christine A.; Poulikakos, Poulikos I.; Tadi, Madhavi; Wang, Weiqing; Taylor, Barry S.; Halilovic, Ensar; Persaud, Yogindra; Xing, Feng; Viale, Agnes; Tsai, James; Chapman, Paul B.; Bollag, Gideon; Solit, David B.; Rosen, Neal

    2010-01-01

    Tumors with mutant BRAF and some with mutant RAS are dependent upon ERK signaling for proliferation, and their growth is suppressed by MAPK/ERK kinase (MEK) inhibitors. In contrast, tumor cells with human EGF receptor (HER) kinase activation proliferate in a MEK-independent manner. These findings have led to the development of RAF and MEK inhibitors as anticancer agents. Like MEK inhibitors, the RAF inhibitor PLX4032 inhibits the proliferation of BRAFV600E tumor cells but not that of HER kinase-dependent tumors. However, tumors with RAS mutation that are sensitive to MEK inhibition are insensitive to PLX4032. MEK inhibitors inhibit ERK phosphorylation in all normal and tumor cells, whereas PLX4032 inhibits ERK signaling only in tumor cells expressing BRAFV600E. In contrast, the drug activates MEK and ERK phosphorylation in cells with wild-type BRAF. In BRAFV600E tumor cells, MEK and RAF inhibitors affect the expression of a common set of genes. PLX4032 inhibits ERK signaling output in mutant BRAF cells, whereas it transiently activates the expression of these genes in tumor cells with wild-type RAF. Thus, PLX4032 inhibits ERK signaling output in a mutant BRAF-selective manner. These data explain why the drug selectively inhibits the growth of mutant BRAF tumors and suggest that it will not cause toxicity resulting from the inhibition of ERK signaling in normal cells. This selectivity may lead to a broader therapeutic index and help explain the greater antitumor activity observed with this drug than with MEK inhibitors. PMID:20668238

  6. 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. PMID:22310290

  7. Inhibitions of several antineoplastic drugs on serum sialic Acid levels in mice bearing tumors.

    PubMed

    Lu, Da-Yong; Xu, Jing; Lu, Ting-Ren; Wu, Hong-Ying; Xu, Bin

    2013-03-01

    Six murine tumors, including ascetic tumors HepA, EC, P388 leukemia, S180 and solid tumor S180, and Lewis lung carcinoma, were employed in this work. The free sialic acid concentrations in both blood and ascites were measured in tumor-bearing mice. The results showed that the content of sialic acids in blood was increased in tumor growth and certain tumor types. Higher sialic acid content was observed in ascites than that present in blood. The influence of antineoplastic agents (vincristine, thiotepa, adriamycin, probimane, cisplatin, oxalysine, cortisone, nitrogen mustard, lycobetaine, Ara-C, harringtonine, and cyclophosphamide) on the content of sialic acids in mice blood bearing solid tumors of either S180 or Lewis lung carcinoma was observed. Different inhibitions of antineoplastic drugs on both tumor growth and serum sialic acid levels in mice bearing tumors were found. Among these antineoplastic drugs, probimane, cisplatin, nitrogen mustard, and lycobetaine were able to decrease the serum sialic acid levels in mice bearing tumors. Since these four antineoplastic drugs are all DNA chelating agents, it was proposed that the inhibition of tumor sialic acids by these drugs might be through the DNA template via two ways. Since we have found no effect of antineoplastic drugs on serum sialic acid levels in normal mice, this suggests that the inhibition of antineoplastic drugs on sialic acids is by tumor involvement. PMID:23641340

  8. 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.

  9. Inhibition of tumor cell proliferation and motility by fibroblasts is both contact and soluble factor dependent

    PubMed Central

    Alkasalias, Twana; Flaberg, Emilie; Kashuba, Vladimir; Alexeyenko, Andrey; Pavlova, Tatiana; Savchenko, Andrii; Szekely, Laszlo; Klein, George; Guven, Hayrettin

    2014-01-01

    Normal human and murine fibroblasts can inhibit proliferation of tumor cells when cocultured in vitro. The inhibitory capacity varies depending on the donor and the site of origin of the fibroblast. We showed previously that effective inhibition requires formation of a morphologically intact fibroblast monolayer before seeding of the tumor cells. Here we show that inhibition is extended to motility of tumor cells and we dissect the factors responsible for these inhibitory functions. We find that inhibition is due to two different sets of molecules: (i) the extracellular matrix (ECM) and other surface proteins of the fibroblasts, which are responsible for contact-dependent inhibition of tumor cell proliferation; and (ii) soluble factors secreted by fibroblasts when confronted with tumor cells (confronted conditioned media, CCM) contribute to inhibition of tumor cell proliferation and motility. However, conditioned media (CM) obtained from fibroblasts alone (nonconfronted conditioned media, NCM) did not inhibit tumor cell proliferation and motility. In addition, quantitative PCR (Q-PCR) data show up-regulation of proinflammatory genes. Moreover, comparison of CCM and NCM with an antibody array for 507 different soluble human proteins revealed differential expression of growth differentiation factor 15, dickkopf-related protein 1, endothelial-monocyte-activating polypeptide II, ectodysplasin A2, Galectin-3, chemokine (C-X-C motif) ligand 2, Nidogen1, urokinase, and matrix metalloproteinase 3. PMID:25404301

  10. FTY720 (fingolimod) sensitizes prostate cancer cells to radiotherapy by inhibition of sphingosine kinase-1.

    PubMed

    Pchejetski, Dmitri; Bohler, Torsten; Brizuela, Leyre; Sauer, Lysann; Doumerc, Nicolas; Golzio, Muriel; Salunkhe, Vishal; Teissié, Justin; Malavaud, Bernard; Waxman, Jonathan; Cuvillier, Olivier

    2010-11-01

    Radiotherapy is widely used as a radical treatment for prostate cancer, but curative treatments are elusive for poorly differentiated tumors where survival is just 15% at 15 years. Dose escalation improves local response rates but is limited by tolerance in normal tissues. A sphingosine analogue, FTY720 (fingolimod), a drug currently in phase III studies for treatment of multiple sclerosis, has been found to be a potent apoptosis inducer in prostate cancer cells. Using in vitro and in vivo approaches, we analyzed the impact of FTY720 on sphingolipid metabolism in hormone-refractory metastatic prostate cancer cells and evaluated its potential as a radiosensitizer on cell lines and prostate tumor xenografts. In prostate cancer cell lines, FTY720 acted as a sphingosine kinase 1 (SphK1) inhibitor that induced prostate cancer cell apoptosis in a manner independent of sphingosine-1-phosphate receptors. In contrast, γ irradiation did not affect SphK1 activity in prostate cancer cells yet synergized with FTY720 to inhibit SphK1. In mice bearing orthotopic or s.c. prostate cancer tumors, we show that FTY720 dramatically increased radiotherapeutic sensitivity, reducing tumor growth and metastasis without toxic side effects. Our findings suggest that low, well-tolerated doses of FTY720 could offer significant improvement to the clinical treatment of prostate cancer. PMID:20959468

  11. Inhibition of metastatic tumor growth by targeted delivery of antioxidant enzymes.

    PubMed

    Nishikawa, Makiya; Hyoudou, Kenji; Kobayashi, Yuki; Umeyama, Yukari; Takakura, Yoshinobu; Hashida, Mitsuru

    2005-12-01

    To develop effective anti-metastatic therapy, targeted or sustained delivery of catalase was examined in mice. We found that mouse lung with metastatic colonies of adenocarcinoma colon26 cells exhibited reduced catalase activity. The interaction of the tumor cells with macrophages or hepatocytes generated detectable amounts of ROS, and increased the activity of matrix metalloproteinases. Hepatocyte-targeted delivery of catalase was successfully achieved by galactosylation, which was highly effective in inhibiting the hepatic metastasis of colon26 cells. PEGylation, which increased the retention of catalase in the circulation, effectively inhibited the pulmonary metastasis of the cells. To examine which processes in tumor metastasis are inhibited by catalase derivatives, the tissue distribution and proliferation of tumor cells in mice was quantitatively analyzed using firefly luciferase-expressing tumor cells. An injection of PEG-catalase just before the inoculation of melanoma B16-BL6/Luc cells significantly reduced the number of the tumor cells in the lung at 24 h. Daily dosing of PEG-catalase greatly inhibited the proliferation of the tumor cells, and increased the survival rate of the tumor-bearing mice. These results indicate that targeted or sustained delivery of catalase to sites where tumor cells metastasize is a promising approach for inhibiting metastatic tumor growth. PMID:16256238

  12. 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

  13. Inhibition of lactate transport in Ehrlich ascites tumor cells and human erythrocytes by a synthetic anhydride of lactic acid.

    PubMed

    Johnson, J H; Belt, J A; Dubinsky, W P; Zimniak, A; Racker, E

    1980-08-01

    The synthesis and some of the physical and biological characteristics of a new inhibitor of lactate transport are described. The inhibitor is isobutylcarbonyl lactayl anhydride (iBCLA). It is formed by the condensation of lactic acid and isobutylchloroformate. It inhibits lactate transport 50% at 0.5 microgram/mg of protein in both Ehrlich ascites tumor cells and human erythrocytes. In contrast, 15 microgram of iBCLA/mg of protein is required for 50% inhibition of phosphate transport in erythrocytes, and phosphate transport in Ehrlich ascites tumor cells is unaffected at levels as high as 50 microgram of iBCLA/mg of protein. A time-dependent and concentration-dependent reversal of lactate transport inhibition took place on exposure of iBCLA-treated Ehrlich ascites cells to hydroxylamine or dithiothreitol. These data, along with the observed sensitivity of the lactate transporter to sulfhydryl reagents [Spencer, T. L., & Lehninger, A. L. (1976) Biochem. J. 154, 405-414], suggest that iBCLA acylates an essential sulfhydryl group on the transporter. When glycolyzing Ehrlich ascites tumor cells were treated with concentrations of iBCLA sufficient for complete inhibition of lactate transport, intracellular lactate levels increased, intracellular pH and extra-cellular lactate levels decreased, and overall lactate production was inhibited. PMID:7407072

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

    PubMed

    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

  15. 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

  16. An epitope-specific novel anti-EMMPRIN polyclonal antibody inhibits tumor progression

    PubMed Central

    Walter, Miriam; Simanovich, Elina; Brod, Vera; Lahat, Nitza; Bitterman, Haim; Rahat, Michal A.

    2016-01-01

    ABSTRACT Extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) mediates tumor cell–macrophage interactions, and has been shown to induce both matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF). However, the epitope responsible for MMP induction is controversial, and the epitope responsible for VEGF induction is yet unknown. We generated a novel anti-EMMPRIN antibody directed against a specific epitope that successfully inhibited the production of both MMP-9 and VEGF in tumor cell–macrophage in vitro co-culture systems, exhibiting a U-shaped dose response. Furthermore, this antibody efficiently inhibited in vivo tumor progression in both the RENCA renal cell carcinoma and CT26 colon carcinoma subcutaneous tumor models, and reduced tumor size and number of metastatic foci in the 4T1 orthotopic model. This was achieved by inhibiting angiogenesis as assessed by immunohistochemical staining for the endothelial marker CD31, by inhibiting tumor cell proliferation as assessed by the staining for Ki-67, and by enhancing tumor cell apoptosis as assessed in the TUNEL assay. Moreover, administration of the antibody recruited more macrophages into the tumor, and skewed the tumor microenvironment for macrophages from TGFβ-dominated anti-inflammatory microenvironment, to a less immunosuppressive one. The antibody improved the ability of stimulated macrophages to perform antibody-dependent cell cytotoxicity (ADCC) and kill tumor cells. Thus, our new antibody maps the epitope capable of inducing both MMPs and VEGF, and places EMMPRIN as a good target for cancer therapy. PMID:27057452

  17. 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. PMID:3593337

  18. The Selective PI3K Inhibitor XL147 (SAR245408) Inhibits Tumor Growth and Survival and Potentiates the Activity of Chemotherapeutic Agents in Preclinical Tumor Models.

    PubMed

    Foster, Paul; Yamaguchi, Kyoko; Hsu, Pin P; Qian, Fawn; Du, Xiangnan; Wu, Jianming; Won, Kwang-Ai; Yu, Peiwen; Jaeger, Christopher T; Zhang, Wentao; Marlowe, Charles K; Keast, Paul; Abulafia, Wendy; Chen, Jason; Young, Jenny; Plonowski, Artur; Yakes, F Michael; Chu, Felix; Engell, Kelly; Bentzien, Frauke; Lam, Sanh T; Dale, Stephanie; Yturralde, Olivia; Matthews, David J; Lamb, Peter; Laird, A Douglas

    2015-04-01

    Dysregulation of PI3K/PTEN pathway components, resulting in hyperactivated PI3K signaling, is frequently observed in various cancers and correlates with tumor growth and survival. Resistance to a variety of anticancer therapies, including receptor tyrosine kinase (RTK) inhibitors and chemotherapeutic agents, has been attributed to the absence or attenuation of downregulating signals along the PI3K/PTEN pathway. Thus, PI3K inhibitors have therapeutic potential as single agents and in combination with other therapies for a variety of cancer indications. XL147 (SAR245408) is a potent and highly selective inhibitor of class I PI3Ks (α, β, γ, and δ). Moreover, broad kinase selectivity profiling of >130 protein kinases revealed that XL147 is highly selective for class I PI3Ks over other kinases. In cellular assays, XL147 inhibits the formation of PIP3 in the membrane, and inhibits phosphorylation of AKT, p70S6K, and S6 in multiple tumor cell lines with diverse genetic alterations affecting the PI3K pathway. In a panel of tumor cell lines, XL147 inhibits proliferation with a wide range of potencies, with evidence of an impact of genotype on sensitivity. In mouse xenograft models, oral administration of XL147 results in dose-dependent inhibition of phosphorylation of AKT, p70S6K, and S6 with a duration of action of at least 24 hours. Repeat-dose administration of XL147 results in significant tumor growth inhibition in multiple human xenograft models in nude mice. Administration of XL147 in combination with chemotherapeutic agents results in antitumor activity in xenograft models that is enhanced over that observed with the corresponding single agents. PMID:25637314

  19. 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.

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

    PubMed

    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

  1. 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

  2. Anti-tumor effect of inhibition of IL-6 signaling in mucoepidermoid carcinoma

    PubMed Central

    Mochizuki, Daiki; Adams, April; Warner, Kristy A.; Zhang, Zhaocheng; Pearson, Alexander T.; Misawa, Kiyoshi; McLean, Scott A.; Wolf, Gregory T.; Nör, Jacques E.

    2015-01-01

    Mucoepidermoid carcinoma (MEC) is the most frequent malignant salivary gland cancer. Response to chemoradiotherapy is modest, and therefore radical surgery remains the standard-of-care. Emerging evidence suggests that Interleukin (IL)-6 signaling correlates with the survival of cancer stem cells and resistance to therapy. Here, we investigated whether inhibition of IL-6 receptor (IL-6R) signaling with tocilizumab (humanized anti-human IL-6R antibody) sensitizes MEC to chemotherapy using human mucoepidermoid carcinoma cell lines (UM-HMC) and correspondent xenograft models. In vitro, we observed that tocilizumab inhibited STAT3 phosphorylation but had no measurable effect in MEC cell viability (UM-HMC-1,-3A,-3B). In contrast, the anti-tumor effect of single agent tocilizumab on MEC xenografts was comparable to paclitaxel or cisplatin. Combination of tocilizumab with cisplatin or paclitaxel enhanced the inhibitory effect of chemotherapy on xenograft growth (P < 0.05), time to failure (P < 0.01), decreased vascular endothelial growth factor (VEGF) expression and tumor microvessel density (P < 0.05) without added systemic toxicities. Notably, tocilizumab decreased the fraction of MEC cancer stem cells (ALDHhighCD44high) in vitro, and prevented paclitaxel-induced increase in the fraction of cancer stem cells in vivo (P < 0.05). Collectively, these findings demonstrate that tocilizumab enhances the anti-tumor effect of conventional chemotherapy in preclinical models of mucoepidermoid carcinoma, and suggest that patients might benefit from combination therapy with an inhibitor of IL-6R signaling and chemotherapeutic agent such as paclitaxel. PMID:26287605

  3. Tetrandrine inhibits Wnt/β-catenin signaling and suppresses tumor growth of human colorectal cancer.

    PubMed

    He, Bai-Cheng; Gao, Jian-Li; Zhang, Bing-Qiang; Luo, Qing; Shi, Qiong; Kim, Stephanie H; Huang, Enyi; Gao, Yanhong; Yang, Ke; Wagner, Eric R; Wang, Linyuan; Tang, Ni; Luo, Jinyong; Liu, Xing; Li, Mi; Bi, Yang; Shen, Jikun; Luther, Gaurav; Hu, Ning; Zhou, Qixin; Luu, Hue H; Haydon, Rex C; Zhao, Yingming; He, Tong-Chuan

    2011-02-01

    As one of the most common malignancies, colon cancer is initiated by abnormal activation of the Wnt/β-catenin pathway. Although the treatment options have increased for some patients, overall progress has been modest. Thus, there is a great need to develop new treatments. We have found that bisbenzylisoquinoline alkaloid tetrandrine (TET) exhibits anticancer activity. TET is used as a calcium channel blocker to treat hypertensive and arrhythmic conditions in Chinese medicine. Here, we investigate the molecular basis underlying TET's anticancer activity. We compare TET with six chemotherapy drugs in eight cancer lines and find that TET exhibits comparable anticancer activities with camptothecin, vincristine, paclitaxel, and doxorubicin, and better than that of 5-fluorouracil (5-FU) and carboplatin. TET IC₅₀ is ≤5 μM in most of the tested cancer lines. TET exhibits synergistic anticancer activity with 5-FU and reduces migration and invasion capabilities of HCT116 cells. Furthermore, TET induces apoptosis and inhibits xenograft tumor growth of colon cancer. TET treatment leads to a decrease in β-catenin protein level in xenograft tumors, which is confirmed by T-cell factor/lymphocyte enhancer factor and c-Myc reporter assays. It is noteworthy that HCT116 cells with allelic oncogenic β-catenin deleted are less sensitive to TET-mediated inhibition of proliferation, viability, and xenograft tumor growth. Thus, our findings strongly suggest that the anticancer effect of TET in colon cancer may be at least in part mediated by targeting β-catenin activity. Therefore, TET may be used alone or in combination as an effective anticancer agent. PMID:20978119

  4. Anti-tumor effect of inhibition of IL-6 signaling in mucoepidermoid carcinoma.

    PubMed

    Mochizuki, Daiki; Adams, April; Warner, Kristy A; Zhang, Zhaocheng; Pearson, Alexander T; Misawa, Kiyoshi; McLean, Scott A; Wolf, Gregory T; Nör, Jacques E

    2015-09-01

    Mucoepidermoid carcinoma (MEC) is the most frequent malignant salivary gland cancer. Response to chemoradiotherapy is modest, and therefore radical surgery remains the standard-of-care. Emerging evidence suggests that Interleukin (IL)-6 signaling correlates with the survival of cancer stem cells and resistance to therapy. Here, we investigated whether inhibition of IL-6 receptor (IL-6R) signaling with tocilizumab (humanized anti-human IL-6R antibody) sensitizes MEC to chemotherapy using human mucoepidermoid carcinoma cell lines (UM-HMC) and correspondent xenograft models. In vitro, we observed that tocilizumab inhibited STAT3 phosphorylation but had no measurable effect in MEC cell viability (UM-HMC-1,-3A,-3B). In contrast, the anti-tumor effect of single agent tocilizumab on MEC xenografts was comparable to paclitaxel or cisplatin. Combination of tocilizumab with cisplatin or paclitaxel enhanced the inhibitory effect of chemotherapy on xenograft growth (P < 0.05), time to failure (P < 0.01), decreased vascular endothelial growth factor (VEGF) expression and tumor microvessel density (P < 0.05) without added systemic toxicities. Notably, tocilizumab decreased the fraction of MEC cancer stem cells (ALDH(high)CD44(high)) in vitro, and prevented paclitaxel-induced increase in the fraction of cancer stem cells in vivo (P < 0.05). Collectively, these findings demonstrate that tocilizumab enhances the anti-tumor effect of conventional chemotherapy in preclinical models of mucoepidermoid carcinoma, and suggest that patients might benefit from combination therapy with an inhibitor of IL-6R signaling and chemotherapeutic agent such as paclitaxel. PMID:26287605

  5. JAK2 inhibition sensitizes resistant EGFR-mutant lung adenocarcinoma to tyrosine kinase inhibitors

    PubMed Central

    Gao, Sizhi P.; Chang, Qing; Mao, Ninghui; Daly, Laura A.; Vogel, Robert; Chan, Tyler; Liu, Shu Hui; Bournazou, Eirini; Schori, Erez; Zhang, Haiying; Brewer, Monica Red; Pao, William; Morris, Luc; Ladanyi, Marc; Arcila, Maria; Manova-Todorova, Katia; de Stanchina, Elisa; Norton, Larry; Levine, Ross L.; Altan-Bonnet, Gregoire; Solit, David; Zinda, Michael; Huszar, Dennis; Lyden, David; Bromberg, Jacqueline F.

    2016-01-01

    Lung adenocarcinomas with mutant epidermal growth factor receptor (EGFR) respond to EGFR-targeted tyrosine kinase inhibitors (TKIs), but resistance invariably occurs. We found that the Janus kinase (JAK)/signal transduction and activator of transcription 3 (STAT3) signaling pathway was aberrantly increased in TKI-resistant EGFR-mutant non–small cell lung cancer (NSCLC) cells. JAK2 inhibition restored sensitivity to the EGFR inhibitor erlotinib in TKI-resistant cell lines and xenograft models of EGFR-mutant TKI-resistant lung cancer. JAK2 inhibition uncoupled EGFR from its negative regulator, suppressor of cytokine signaling 5 (SOCS5), consequently increasing EGFR abundance and restoring the tumor cells’ dependence on EGFR signaling. Furthermore, JAK2 inhibition led to heterodimerization of mutant and wild-type EGFR subunits, the activity of which was then blocked by TKIs. Our results reveal a mechanism whereby JAK2 inhibition overcomes acquired resistance to EGFR inhibitors and support the use of combination therapy with JAK and EGFR inhibitors for the treatment of EGFR-dependent NSCLC. PMID:27025877

  6. JAK2 inhibition sensitizes resistant EGFR-mutant lung adenocarcinoma to tyrosine kinase inhibitors.

    PubMed

    Gao, Sizhi P; Chang, Qing; Mao, Ninghui; Daly, Laura A; Vogel, Robert; Chan, Tyler; Liu, Shu Hui; Bournazou, Eirini; Schori, Erez; Zhang, Haiying; Red Brewer, Monica; Pao, William; Morris, Luc; Ladanyi, Marc; Arcila, Maria; Manova-Todorova, Katia; de Stanchina, Elisa; Norton, Larry; Levine, Ross L; Altan-Bonnet, Gregoire; Solit, David; Zinda, Michael; Huszar, Dennis; Lyden, David; Bromberg, Jacqueline F

    2016-01-01

    Lung adenocarcinomas with mutant epidermal growth factor receptor (EGFR) respond to EGFR-targeted tyrosine kinase inhibitors (TKIs), but resistance invariably occurs. We found that the Janus kinase (JAK)/signal transduction and activator of transcription 3 (STAT3) signaling pathway was aberrantly increased in TKI-resistant EGFR-mutant non-small cell lung cancer (NSCLC) cells. JAK2 inhibition restored sensitivity to the EGFR inhibitor erlotinib in TKI-resistant cell lines and xenograft models of EGFR-mutant TKI-resistant lung cancer. JAK2 inhibition uncoupled EGFR from its negative regulator, suppressor of cytokine signaling 5 (SOCS5), consequently increasing EGFR abundance and restoring the tumor cells' dependence on EGFR signaling. Furthermore, JAK2 inhibition led to heterodimerization of mutant and wild-type EGFR subunits, the activity of which was then blocked by TKIs. Our results reveal a mechanism whereby JAK2 inhibition overcomes acquired resistance to EGFR inhibitors and support the use of combination therapy with JAK and EGFR inhibitors for the treatment of EGFR-dependent NSCLC. PMID:27025877

  7. DSGOST inhibits tumor growth by blocking VEGF/VEGFR2-activated angiogenesis

    PubMed Central

    Choi, Hyeong Sim; Lee, Kangwook; Kim, Min Kyoung; Lee, Kang Min; Shin, Yong Cheol; Cho, Sung-Gook; Ko, Seong-Gyu

    2016-01-01

    Tumor growth requires a process called angiogenesis, a new blood vessel formation from pre-existing vessels, as newly formed vessels provide tumor cells with oxygen and nutrition. Danggui-Sayuk-Ga-Osuyu-Saenggang-Tang (DSGOST), one of traditional Chinese medicines, has been widely used in treatment of vessel diseases including Raynaud's syndrome in Northeast Asian countries including China, Japan and Korea. Therefore, we hypothesized that DSGOST might inhibit tumor growth by targeting newly formed vessels on the basis of its historical prescription. Here, we demonstrate that DSGOST inhibits tumor growth by inhibiting VEGF-induced angiogenesis. DSGOST inhibited VEGF-induced angiogenic abilities of endothelial cells in vitro and in vivo, which resulted from its inhibition of VEGF/VEGFR2 interaction. Furthermore, DSGOST attenuated pancreatic tumor growth in vivo by reducing angiogenic vessel numbers, while not affecting pancreatic tumor cell viability. Thus, our data conclude that DSGOST inhibits VEGF-induced tumor angiogenesis, suggesting a new indication for DSGOST in treatment of cancer. PMID:26967562

  8. Violacein induces p44/42 mitogen-activated protein kinase-mediated solid tumor cell death and inhibits tumor cell migration

    PubMed Central

    MEHTA, TORAL; VERCRUYSSE, KOEN; JOHNSON, TERRANCE; EJIOFOR, ANTHONY OKECHUKWU; MYLES, ELBERT; QUICK, QUINCY ANTOINE

    2015-01-01

    Microbial secondary metabolites have emerged as alternative novel drugs for the treatment of human cancers. Violacein, a purple pigment produced by Chromobacterium violaceum, was investigated in the present study for its anti-tumor properties in tumor cell lines. Clinically applicable concentrations of violacein were demonstrated to inhibit the proliferative capacity of tumor cell lines according to a crystal violet proliferation assay. The underlying mechanism was the promotion of apoptotic cell death, as indicated by poly(ADP ribose) polymerase cleavage and p44/42 mitogen-activated protein kinase signaling determined by western blot analysis. Collectively, this provided mechanistic evidence that violacein elicits extracellular-signal regulated kinase-induced apoptosis via the intrinsic pathway. The anti-malignant properties of violacein in the present study were further demonstrated by its inhibitory effects on brain tumor cell migration, specifically glioblastomas, one of the most invasive and therapeutically resistant neoplasms in the clinic. Additionally, solid tumors examined in the present study displayed differential cellular responses and sensitivities to violacein as observed by morphologically induced cellular changes that contributed to its anti-migratory properties. In conclusion, violacein is a novel natural product with the potential to kill several types of human tumor cell lines, as well as prevent disease recurrence by antagonizing cellular processes that contribute to metastatic invasion. PMID:25816226

  9. Inhibition of adhesion and proliferation of peritoneally disseminated tumor cells by pegylated catalase.

    PubMed

    Hyoudou, Kenji; Nishikawa, Makiya; Kobayashi, Yuki; Kuramoto, Yukari; Yamashita, Fumiyoshi; Hashida, Mitsuru

    2006-01-01

    Hydrogen peroxide may aggravate the peritoneal dissemination of tumor cells by activating the expression of a variety of genes. In this study, we used pegylated catalase (PEG-catalase) to examine whether prolonged retention of catalase activity within the peritoneal cavity is effective in inhibiting peritoneal dissemination in mouse models. Murine B16-BL6 cells or colon 26 cells labeled with firefly luciferase gene were inoculated intraperitoneally into syngeneic mice. Compared with unmodified catalase, PEG-catalase was retained in the peritoneal cavity for a long period after intraperitoneal injection. A single injection of PEG-catalase just before tumor inoculation significantly reduced the number of the tumor cells at 1 and 7 days. The changes in the expression of molecules involved in the metastasis were evaluated by real time quantitative PCR analysis. Inoculation of the tumor cells increased the expression of intercellular adhesion molecule (ICAM)-1 in the greater omentum, which was inhibited by PEG-catalase. An injection of PEG-catalase at 3 days after tumor inoculation also reduced the number of the tumor cells, suggesting that processes other than the adhesion of tumor cells to peritoneal organs are also inhibited. Daily doses of PEG-catalase significantly prolonged the survival time of tumor-bearing mice. These results indicate that intraperitoneal injection of PEG-catalase inhibits the multiple processes of peritoneal dissemination of tumor cells by scavenging hydrogen peroxide in the peritoneal cavity. PMID:17086358

  10. 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

  11. 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.

  12. Dopamine receptor antagonist thioridazine inhibits tumor growth in a murine breast cancer model.

    PubMed

    Yin, Tao; He, Sisi; Shen, Guobo; Ye, Tinghong; Guo, Fuchun; Wang, Yongsheng

    2015-09-01

    Neuropsychological factors have been shown to influence tumor progression and therapeutic response. The present study investigated the effect of the dopamine receptor antagonist thioridazine on murine breast cancer. The anti‑tumor efficacy of thioridazine was assessed using a murine breast cancer model. Cell apoptosis and proliferation were analyzed in vitro using flow cytometry (FCM) and the MTT assay, respectively. Western blot analysis was performed to assess Akt, phosphorylated (p)‑Akt, signal transducer and activator of transcription (STAT) 3, p‑STAT3 and p‑p65 in tumor cells following treatment with thioridazine. The Ki67 index and the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)‑positive apoptotic cells were assessed in the tumor sections. Thioridazine was found to reduce tumor growth, inhibit tumor cell proliferation and induce apoptosis in a dose‑ and time‑dependent manner in vitro. Thioridazine was also found to markedly inhibit tumor proliferation and induce tumor cell apoptosis in vivo as shown by the lower Ki67 index and increase in TUNEL‑positive cells. In addition, thioridazine was observed to inhibit the activation of the canonical nuclear factor κ‑light‑chain‑enhancer of activated B cells pathway and exert anti‑tumor effects by remodeling the tumor stroma, as well as inhibit angiogenesis in the tumor microenvironment. In conclusion, thioridazine was found to significantly inhibit breast tumor growth and the potential for thioridazine to be used in cancer therapy may be re‑evaluated and investigated in clinical settings. PMID:26095429

  13. 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

  14. Radiofrequency thermal ablation of breast tumors combined with intralesional administration of IL-7 and IL-15 augments anti-tumor immune responses and inhibits tumor development and metastasis

    PubMed Central

    Habibi, Mehran; Kmieciak, Maciej; Graham, Laura; Morales, Johanna K; Bear, Harry D; Manjili, Masoud H

    2008-01-01

    Tumor development or recurrence is always a matter of concern following radiofrequency thermal ablation (RFA) of tumors. To determine whether combining RFA with immunologically active cytokines might induce tumor-specific immune responses against mammary carcinoma and inhibit tumor development or metastasis, we evaluated intralesional injection of IL-7 and IL-15 in RFA-treated murine tumors. We used two different breast carcinoma models: neu-overexpressing mouse mammary carcinoma (MMC) in FVBN202 transgenic mouse and 4T1 tumors in Balb/c mouse. MMC tend to relapse even in the presence of neu-specific immune responses, and 4T1 is a weakly immunogenic, aggressive and highly metastatic transplantable tumor. In vivo growth of both of these tumors is also associated with increased numbers of CD11b+Gr1+ myeloid-derived suppressor cells (MDSC). We showed for the first time that unlike RFA alone, RFA combined with the administration of intralesional IL-7 and IL-15 (after RFA), induced immune responses to tumors, inhibited tumor development and lung metastasis, and reduced MDSC. PMID:18425677

  15. 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

    2016-01-01

    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. PMID:27173312

  16. 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. PMID:16307762

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

    PubMed

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

    2016-02-01

    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

  18. Capsaicin Enhances the Drug Sensitivity of Cholangiocarcinoma through the Inhibition of Chemotherapeutic-Induced Autophagy

    PubMed Central

    Hong, Zai-Fa; Zhao, Wen-Xiu; Yin, Zhen-Yu; Xie, Cheng-Rong; Xu, Ya-Ping; Chi, Xiao-Qin; Zhang, Sheng; Wang, Xiao-Min

    2015-01-01

    Cholangiocarcinoma (CCA), a devastating cancer with a poor prognosis, is resistant to the currently available chemotherapeutic agents. Capsaicin, the major pungent ingredient found in hot red chili peppers of the genus Capsicum, suppresses the growth of several malignant cell lines. Our aims were to investigate the role and mechanism of capsaicin with respect to the sensitivity of CCA cells to chemotherapeutic agents. The effect of capsaicin on CCA tumor sensitivity to 5-fluorouracil (5-FU) was assessed in vitro in CCA cells and in vivo in a xenograft model. The drug sensitivity of QBC939 to 5-FU was significantly enhanced by capsaicin compared with either agent alone. In addition, the combination of capsaicin with 5-FU was synergistic, with a combination index (CI) < 1, and the combined treatment also suppressed tumor growth in the CCA xenograft to a greater extent than 5-FU alone. Further investigation revealed that the autophagy induced by 5-FU was inhibited by capsaicin. Moreover, the decrease in AKT and S6 phosphorylation induced by 5-FU was effectively reversed by capsaicin, indicating that capsaicin inhibits 5-FU-induced autophagy by activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway in CCA cells. Taken together, these results demonstrate that capsaicin may be a useful adjunct therapy to improve chemosensitivity in CCA. This effect likely occurs via PI3K/AKT/mTOR pathway activation, suggesting a promising strategy for the development of combination drugs for CCA. PMID:25933112

  19. Capsaicin Enhances the Drug Sensitivity of Cholangiocarcinoma through the Inhibition of Chemotherapeutic-Induced Autophagy.

    PubMed

    Hong, Zai-Fa; Zhao, Wen-Xiu; Yin, Zhen-Yu; Xie, Cheng-Rong; Xu, Ya-Ping; Chi, Xiao-Qin; Zhang, Sheng; Wang, Xiao-Min

    2015-01-01

    Cholangiocarcinoma (CCA), a devastating cancer with a poor prognosis, is resistant to the currently available chemotherapeutic agents. Capsaicin, the major pungent ingredient found in hot red chili peppers of the genus Capsicum, suppresses the growth of several malignant cell lines. Our aims were to investigate the role and mechanism of capsaicin with respect to the sensitivity of CCA cells to chemotherapeutic agents. The effect of capsaicin on CCA tumor sensitivity to 5-fluorouracil (5-FU) was assessed in vitro in CCA cells and in vivo in a xenograft model. The drug sensitivity of QBC939 to 5-FU was significantly enhanced by capsaicin compared with either agent alone. In addition, the combination of capsaicin with 5-FU was synergistic, with a combination index (CI) < 1, and the combined treatment also suppressed tumor growth in the CCA xenograft to a greater extent than 5-FU alone. Further investigation revealed that the autophagy induced by 5-FU was inhibited by capsaicin. Moreover, the decrease in AKT and S6 phosphorylation induced by 5-FU was effectively reversed by capsaicin, indicating that capsaicin inhibits 5-FU-induced autophagy by activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway in CCA cells. Taken together, these results demonstrate that capsaicin may be a useful adjunct therapy to improve chemosensitivity in CCA. This effect likely occurs via PI3K/AKT/mTOR pathway activation, suggesting a promising strategy for the development of combination drugs for CCA. PMID:25933112

  20. 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

  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. PMID:26130651

  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. Pharmacological inhibition of p38 MAPK reduces tumor growth in patient-derived xenografts from colon tumors

    PubMed Central

    Papaioannou, Marilena; Lopez-Casas, Pedro Pablo; Llonch, Elisabet; Hidalgo, Manuel; Gorgoulis, Vassilis G.; Nebreda, Angel R.

    2015-01-01

    Colorectal cancer is a major health problem and the second cause of cancer related death in western countries. Signaling pathways that control tissue homeostasis are often deregulated during tumorigenesis and contribute to tumor development. Studies in mouse models have shown that the p38 MAPK pathway regulates homeostasis in colon epithelial cells but also plays an important role in colon tumor maintenance. In this study, we have investigated the role of p38 MAPK signaling in patient-derived xenografts (PDXs) from three different human colon tumors representing clinical heterogeneity and that recapitulate the human tumor conditions both at histological and molecular levels. We have found that PH797804, a chemical inhibitor of p38 MAPK, reduces tumor growth of the three PDXs, which correlates with impaired colon tumor cell proliferation and survival. The inhibition of p38 MAPK in PDXs results in downregulation of the IL-6/STAT3 signaling pathway, which is a key regulator of colon tumorigenesis. Our results show the importance of p38 MAPK in human colon tumor growth using a preclinical model, and support that inhibition of p38 MAPK signaling may have therapeutic interest for colon cancer treatment. PMID:25890501

  4. Antibody mediated therapy targeting CD47 inhibits tumor progression of hepatocellular carcinoma.

    PubMed

    Xiao, Zhenyu; Chung, Haniee; Banan, Babak; Manning, Pamela T; Ott, Katherine C; Lin, Shin; Capoccia, Benjamin J; Subramanian, Vijay; Hiebsch, Ronald R; Upadhya, Gundumi A; Mohanakumar, Thalachallour; Frazier, William A; Lin, Yiing; Chapman, William C

    2015-05-01

    Human hepatocellular carcinoma (HCC) has a high rate of tumor recurrence and metastasis, resulting in shortened survival times. The efficacy of current systemic therapies for HCC is limited. In this study, we used xenograft tumor models to investigate the use of antibodies that block CD47 and inhibit HCC tumor growth. Immunostaining of tumor tissue and HCC cell lines demonstrated CD47 over-expression in HCC as compared to normal hepatocytes. Macrophage phagocytosis of HCC cells was increased after treatment with CD47 antibodies (CD47mAbs) that block CD47 binding to SIRPα. Further, CD47 blockade inhibited tumor growth in both heterotopic and orthotopic models of HCC, and promoted the migration of macrophages into the tumor mass. Our results demonstrate that targeting CD47 by specific antibodies has potential immunotherapeutic efficacy in human HCC. PMID:25721088

  5. Antibody mediated therapy targeting CD47 inhibits tumor progression of hepatocellular carcinoma

    PubMed Central

    Xiao, Zhenyu; Chung, Haniee; Banan, Babak; Manning, Pamela T.; Ott, Katherine C.; Lin, Shin; Capoccia, Benjamin J.; Subramanian, Vijay; Hiebsch, Ronald R.; Upadhya, Gundumi A.; Mohanakumar, Thalachallour; Frazier, William A.; Lin, Yiing; Chapman, William C.

    2016-01-01

    Human hepatocellular carcinoma (HCC) has a high rate of tumor recurrence and metastasis, resulting in shortened survival times. The efficacy of current systemic therapies for HCC is limited. In this study, we used xenograft tumor models to investigate the use of antibodies that block CD47 and inhibit HCC tumor growth. Immunostaining of tumor tissue and HCC cell lines demonstrated CD47 over-expression in HCC as compared to normal hepatocytes. Macrophage phagocytosis of HCC cells was increased after treatment with CD47 antibodies (CD47mAbs) that block CD47 binding to SIRPα. Further, CD47 blockade inhibited tumor growth in both heterotopic and orthotopic models of HCC, and promoted the migration of macrophages into the tumor mass. Our results demonstrate that targeting CD47 by specific antibodies has potential immunotherapeutic efficacy in human HCC. PMID:25721088

  6. Inhibition of peritoneal dissemination of tumor cells by cationized catalase in mice.

    PubMed

    Hyoudou, Kenji; Nishikawa, Makiya; Kobayashi, Yuki; Mukai, Sakiko; Ikemura, Mai; Kuramoto, Yukari; Yamashita, Fumiyoshi; Hashida, Mitsuru

    2007-05-14

    To inhibit peritoneal dissemination of tumor cells by destroying hydrogen peroxide, ethylenediamine-conjugated catalase (ED-catalase), a cationized derivative, was injected into the peritoneal cavity of mice. ED-catalase had about a 6-fold longer retention time within the cavity than unmodified catalase. Peritoneal dissemination was evaluated after intraperitoneal inoculation of B16-BL6/Luc, a melanoma clone stably expressing firefly luciferase, by measuring luciferase activity. An intraperitoneal injection of ED-catalase just before tumor inoculation significantly reduced the number of tumor cells in peritoneal organs. Catalase was less effective, confirming the importance of the retention of the enzyme within the cavity for the inhibition. ED-catalase injected 3 days after tumor inoculation was also effective in inhibiting tumor growth. A real-time quantitative PCR analysis revealed that ED-catalase significantly suppressed the expression of intercellular adhesion molecule-1. Daily dosing of ED-catalase for 7 days significantly prolonged the survival of tumor-bearing mice. These findings indicate that ED-catalase, which is retained for a long time within the peritoneal cavity, is highly effective in inhibiting the adhesion and proliferation of peritoneally disseminated tumor cells, and in increasing the survival of tumor-bearing mice. PMID:17382424

  7. 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. PMID:19845874

  8. 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

  9. c-Abl Modulates Tumor Cell Sensitivity to Antibody-Dependent Cellular Cytotoxicity (ADCC)

    PubMed Central

    Murray, Joseph C.; Aldeghaither, Dalal; Wang, Shangzi; Nasto, Rochelle E.; Jablonski, Sandra A.; Tang, Yong; Weiner, Louis M.

    2014-01-01

    Monoclonal antibodies can modulate cancer cell signal transduction and recruit antitumor immune effector mechanisms – including antibody-dependent cellular cytotoxicity (ADCC). Although several clinically effective antibodies can promote ADCC, therapeutic resistance is common. We hypothesized that oncogenic signaling networks within tumor cells affect their sensitivity to ADCC. We developed a screening platform and targeted 60 genes derived from an EGFR gene network using RNA interference (RNAi) in an in vitro ADCC model system. Knockdown of GRB7, PRKCE, and ABL1 enhanced ADCC by primary and secondary screens. ABL1 knockdown also reduced cell proliferation, independent of its ADCC enhancement effects. c-Abl overexpression decreased ADCC sensitivity and rescued the effects of ABL1 knockdown. Imatinib inhibition of c-Abl kinase activity also enhanced ADCC – phenocopying ABL1 knockdown – against several EGFR-expressing head-and-neck squamous cell carcinoma (HNSCC) cell lines by ex vivo primary NK cells. Our findings suggest that combining c-Abl inhibition with ADCC-promoting antibodies, such as cetuximab, could translate into increased therapeutic efficacy of monoclonal antibodies. PMID:25300860

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

    PubMed

    Kansal, Rita G; McCravy, Matthew S; Basham, Jacob H; Earl, Joshua A; McMurray, Stacy L; Starner, Chelsey J; Whitt, Michael A; Albritton, Lorraine M

    2016-05-01

    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

  11. 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

  12. 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.

  13. Improved Tumor-Specific Drug Accumulation by Polymer Therapeutics with pH-Sensitive Drug Release Overcomes Chemotherapy Resistance.

    PubMed

    Heinrich, Anne-Kathrin; Lucas, Henrike; Schindler, Lucie; Chytil, Petr; Etrych, Tomáš; Mäder, Karsten; Mueller, Thomas

    2016-05-01

    The success of chemotherapy is limited by poor selectivity of active drugs combined with occurrence of tumor resistance. New star-like structured N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-based drug delivery systems containing doxorubicin attached via a pH-sensitive hydrazone bond were designed and investigated for their ability to overcome chemotherapy resistance. These conjugates combine two strategies to achieve a high drug concentration selectively at the tumor site: (I) high accumulation by passive tumor targeting based on enhanced permeability and retention effect and (II) pH-sensitive site-specific drug release due to an acidic tumor microenvironment. Mice bearing doxorubicin-resistant xenograft tumors were treated with doxorubicin, PBS, poly HPMA (pHPMA) precursor or pHPMA-doxorubicin conjugate at different equivalent doses of 5 mg/kg bodyweight doxorubicin up to a 7-fold total dose using different treatment schedules. Intratumoral drug accumulation was analyzed by fluorescence imaging utilizing intrinsic fluorescence of doxorubicin. Free doxorubicin induced significant toxicity but hardly any tumor-inhibiting effects. Administering at least a 3-fold dose of pHPMA-doxorubicin conjugate was necessary to induce a transient response, whereas doses of about 5- to 6-fold induced strong regressions. Tumors completely disappeared in some cases. The onset of response was differential delayed depending on the tumor model, which could be ascribed to distinct characteristics of the microenvironment. Further fluorescence imaging-based analyses regarding underlying mechanisms of the delayed response revealed a related switch to a more supporting intratumoral microenvironment for effective drug release. In conclusion, the current study demonstrates that the concept of tumor site-restricted high-dose chemotherapy is able to overcome therapy resistance. Mol Cancer Ther; 15(5); 998-1007. ©2016 AACR. PMID:26939698

  14. Temozolomide/PLGA microparticles plus vatalanib inhibits tumor growth and angiogenesis in an orthotopic glioma model.

    PubMed

    Zhang, Yu-Hui; Yue, Zhi-Jian; Zhang, He; Tang, Gu-Sheng; Wang, Yang; Liu, Jian-Min

    2010-11-01

    Temozolomide (TM) has anti-tumor activity in patients with malignant glioma. Implantable poly (D,L-lactide-co-glycolide) (PLGA) microparticles of TM (TM-MS) have been developed, enhancing the cytotoxicity of TM to Glioma C6 cells. Vatalanib, as anti-angiogenic agent, has also shown anti-tumor activity with malignant gliomas. We examined the combined effects of TM-MS and vatalanib in a rat orthotopic glioma model and found TM-MS offered a greater tumor inhibition than TM, and combination treatment with both of them improved the survival time versus single agent therapy. The combination treatment also demonstrated an inhibition to rat glioma tumors, a significant decrease in cell proliferation, an increase in apoptosis, and a lower microvessel density within the glioma tumors. The results suggest that TM-MS can more effectively inhibit tumor than TM, and combination treatment with TM-MS and vatalanib inhibits tumor growth and angiogenesis and may prove to be a promising therapy for malignant gliomas. PMID:20816959

  15. Rat hormone sensitive lipase inhibition by cyclipostins and their analogs.

    PubMed

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

    2015-03-01

    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 400nM). 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 50μM. 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 40nM and a rate constant for inactivation of 0.2min(-1). These results are similar to those observed for cyclophostin and AChE. PMID:25678014

  16. 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

  17. CDKN3 expression is negatively associated with pathological tumor stage and CDKN3 inhibition promotes cell survival in hepatocellular carcinoma

    PubMed Central

    Dai, Wei; Miao, Huilai; Fang, Shuo; Fang, Tao; Chen, Nianping; Li, Mingyi

    2016-01-01

    Aberrant expression of CDKN3 may be involved in carcinogenesis of liver cancer. The effect of CDKN3 on tumorigenesis and the molecular mechanisms involved have not been fully elucidated. Immunohistochemistry was performed to detect CDKN3 expression levels in tumor tissues. CDKN3 siRNA was used to knockdown CDKN3 in QGY7701 hepatocellular carcinoma (HCC) cells. Colony formation assay was used to measure the clonogenic capacity of the tumor cells. Cell viability was determined by MTT assay. Logistic regression was performed to analyze the association between CDKN3 expression level and the HCC clinical pathology index. The CDKN3 expression level was significantly decreased in HCC tumor tissues compared with normal liver tissue and liver cirrhosis tissue. Additionally, CDKN3 expression was negatively-associated with the pathological stage of the tumor. Inhibition of CKDN3 promoted the clonogenic capacity and chemotherapeutic tolerance in HCC tissues compared with controls. Knockdown of CDKN3 resulted in downregulation of p53 and p21 protein levels, whereas, AKT serine/threonine kinase 1 expression was upregulated. Thus, CDKN3 expression may reduce the survival of tumor cells and alter the sensitivity to therapeutic agents via the AKT/P53/P21 signaling pathway. Therefore, CDKN3 may be involved in tumor differentiation and self-renewal. PMID:27314282

  18. Marked inhibition of tumor growth in a malignant glioma tumor model by a novel synthetic matrix metalloproteinase inhibitor AG3340.

    PubMed

    Price, A; Shi, Q; Morris, D; Wilcox, M E; Brasher, P M; Rewcastle, N B; Shalinsky, D; Zou, H; Appelt, K; Johnston, R N; Yong, V W; Edwards, D; Forsyth, P

    1999-04-01

    Synthetic matrix metalloproteinase (MMP) inhibitors have activity against a variety of tumors in preclinical models but have not been studied in gliomas. We determined the effect of AG3340, a novel synthetic MMP inhibitor with Ki values against gelatinases in the low picomolar range, on the growth of a human malignant glioma cell line (U87) in SCID-NOD mice. Mice were injected s.c. with U87 cells. Tumors were allowed to grow to a size of approximately 0.5 x 0.5 cm (after about 3 weeks), and the mice were randomized to receive either: (a) 100 mg/kg AG3340 in vehicle; or (b) vehicle control (0.5% carboxymethyl cellulose, 0.1% pluronic F68), both given daily i.p. Tumor area was measured twice weekly, and animals were sacrificed when moribund, or earlier if premorbid histology was examined. In vivo inhibition of tumor growth was profound, with AG3340 decreasing tumor size by 78% compared with controls after 31 days (when controls were sacrificed; P < 0.01, Wilcoxon test). Control animals survived 31 days after the i.p. injections began, and AG3340 mice survived 71 days, representing a >2-fold increase in survival associated with tumor growth delay. Histological examination found that AG3340-treated tumors were smaller, had lower rates of proliferation, and significantly less invasion than control-treated tumors. Hepatic or pulmonary metastases were not seen in either group. In a separate experiment, the tumors were smaller and sampled after a shorter duration of treatment; the changes in proliferation were more marked and occurred earlier than differences in tumor invasion between the two groups. Furthermore, in vitro cell growth was not inhibited at AG3340 concentrations of <1 mM. AG3340 plasma concentrations in vivo, 1 h after administration, ranged from 67 to 365 nM. Thus, AG3340 produced a profound inhibition of glioma tumor growth and invasion. AG3340 markedly increased survival in this in vivo glioma model. Treatment with AG3340 may be potentially useful in

  19. Vascular tumors have increased p70 S6-kinase activation and are inhibited by topical rapamycin.

    PubMed

    Du, Wa; Gerald, Damien; Perruzzi, Carole A; Rodriguez-Waitkus, Paul; Enayati, Ladan; Krishnan, Bhuvaneswari; Edmonds, Joseph; Hochman, Marcelo L; Lev, Dina C; Phung, Thuy L

    2013-10-01

    Vascular tumors are endothelial cell neoplasms whose cellular and molecular mechanisms, leading to tumor formation, are poorly understood, and current therapies have limited efficacy with significant side effects. We have investigated mechanistic (mammalian) target of rapamycin (mTOR) signaling in benign and malignant vascular tumors, and the effects of mTOR kinase inhibitor as a potential therapy for these lesions. Human vascular tumors (infantile hemangioma and angiosarcoma) were analyzed by immunohistochemical stains and western blot for the phosphorylation of p70 S6-kinase (S6K) and S6 ribosomal protein (S6), which are activated downstream of mTOR complex-1 (mTORC1). To assess the function of S6K, tumor cells with genetic knockdown of S6K were analyzed for cell proliferation and migration. The effects of topical rapamycin, an mTOR inhibitor, on mTORC1 and mTOR complex-2 (mTORC2) activities, as well as on tumor growth and migration, were determined. Vascular tumors showed increased activation of S6K and S6. Genetic knockdown of S6K resulted in reduced tumor cell proliferation and migration. Rapamycin fully inhibited mTORC1 and partially inhibited mTORC2 activities, including the phosphorylation of Akt (serine 473) and PKCα, in vascular tumor cells. Rapamycin significantly reduced vascular tumor growth in vitro and in vivo. As a potential localized therapy for cutaneous vascular tumors, topically applied rapamycin effectively reduced tumor growth with limited systemic drug absorption. These findings reveal the importance of mTOR signaling pathways in benign and malignant vascular tumors. The mTOR pathway is an important therapeutic target in vascular tumors, and topical mTOR inhibitors may provide an alternative and well-tolerated therapy for the treatment of cutaneous vascular lesions. PMID:23938603

  20. 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

  1. Nitric Oxide Synthase Inhibition by NG-Nitro-l-Arginine Methyl Ester Inhibits Tumor-Induced Angiogenesis in Mammary Tumors

    PubMed Central

    Jadeski, Lorraine C.; Lala, Peeyush K.

    1999-01-01

    Using a murine breast cancer model, we earlier found a positive correlation between the expression of nitric oxide synthase (NOS) and tumor progression; treatment with inhibitors of NOS, NG-methyl-l-arginine (NMMA) and NG-nitro-l-arginine methyl ester (L-NAME), had antitumor and antimetastatic effects that were partly attributed to reduced tumor cell invasiveness. In the present study, we used a novel in vivo model of tumor angiogenesis using subcutaneous implants of tumor cells suspended in growth factor-reduced Matrigel to examine the angiogenic role of NO in a highly metastatic murine mammary adenocarcinoma cell line. This cell line, C3L5, expresses endothelial (e) NOS in vitro and in vivo, and inducible (i) NOS in vitro on stimulation with lipopolysaccharide and interferon-γ. Female C3H/HeJ mice received subcutaneous implants of growth factor-reduced Matrigel inclusive of C3L5 cells on one side, and on the contralateral side, Matrigel alone; L-NAME and D-NAME (inactive enantiomer) were subsequently administered for 14 days using osmotic minipumps. Immediately after sacrifice, implants were removed and processed for immunolocalization of eNOS and iNOS proteins, and measurement of angiogenesis. Neovascularization was quantified in sections stained with Masson’s trichrome or immunostained for the endothelial cell specific CD31 antigen. While most tumor cells and endothelial cells expressed immunoreactive eNOS protein, iNOS was localized in endothelial cells and some macrophages within the tumor-inclusive implants. Measurable angiogenesis occurred only in implants containing tumor cells. Irrespective of the method of quantification used, tumor-induced neovascularization was significantly reduced in L-NAME-treated mice relative to those treated with D-NAME. The quantity of stromal tissue was lower, but the quantity of necrotic tissue higher in L-NAME relative to D-NAME-treated animals. The total mass of viable tissue (ie, stroma and tumor cells) was lower in L

  2. Conditional ablation of Ikkb inhibits melanoma tumor development in mice

    PubMed Central

    Yang, Jinming; Splittgerber, Ryan; Yull, Fiona E.; Kantrow, Sara; Ayers, Gregory D.; Karin, Michael; Richmond, Ann

    2010-01-01

    Several lines of evidence suggest that tumor cells show elevated activity of the NF-κB transcription factor, a phenomenon often resulting from constitutive activity of IκB kinase β (IKKβ). However, others have found that loss of NF-κB activity or IKKβ is tumor promoting. The role of NF-κB in tumor progression is therefore controversial and varies with tumor type. We sought to more extensively investigate the role IKKβ in melanoma tumor development by specifically disrupting Ikkb in melanocytes in an established mouse model of spontaneous melanoma, whereby HRasV12 is expressed in a melanocyte-specific, doxycycline-inducible manner in mice null for the gene encoding the tumor suppressor inhibitor cyclin-dependent kinase 4/alternative reading frame (Ink4a/Arf). Our results show that Ink4a/Arf–/– mice with melanocyte-specific deletion of Ikkb were protected from HRasV12-initiated melanoma only when p53 was expressed. This protection was accompanied by cell cycle arrest, with reduced cyclin-dependent kinase 2 (Cdk2), Cdk4, Aurora kinase A, and Aurora kinase B expression. Increased p53-mediated apoptosis was also observed, with decreased expression of the antiapoptotic proteins Bcl2 and survivin. Enhanced stabilization of p53 involved increased phosphorylation at Ser15 and reduced phosphorylation of double minute 2 (Mdm2) at Ser166. Together, our findings provide genetic and mechanistic evidence that mutant HRas initiation of tumorigenesis requires Ikkβ-mediated NF-κB activity. PMID:20530876

  3. Cinnamon extract induces tumor cell death through inhibition of NFκB and AP1

    PubMed Central

    2010-01-01

    Background Cinnamomum cassia bark is the outer skin of an evergreen tall tree belonging to the family Lauraceae containing several active components such as essential oils (cinnamic aldehyde and cinnamyl aldehyde), tannin, mucus and carbohydrate. They have various biological functions including anti-oxidant, anti-microbial, anti-inflammation, anti-diabetic and anti-tumor activity. Previously, we have reported that anti-cancer effect of cinnamon extracts is associated with modulation of angiogenesis and effector function of CD8+ T cells. In this study, we further identified that anti-tumor effect of cinnamon extracts is also link with enhanced pro-apoptotic activity by inhibiting the activities NFκB and AP1 in mouse melanoma model. Methods Water soluble cinnamon extract was obtained and quality of cinnamon extract was evaluated by HPLC (High Performance Liquid Chromatography) analysis. In this study, we tested anti-tumor activity and elucidated action mechanism of cinnamon extract using various types of tumor cell lines including lymphoma, melanoma, cervix cancer and colorectal cancer in vitro and in vivo mouse melanoma model. Results Cinnamon extract strongly inhibited tumor cell proliferation in vitro and induced active cell death of tumor cells by up-regulating pro-apoptotic molecules while inhibiting NFκB and AP1 activity and their target genes such as Bcl-2, BcL-xL and survivin. Oral administration of cinnamon extract in melanoma transplantation model significantly inhibited tumor growth with the same mechanism of action observed in vitro. Conclusion Our study suggests that anti-tumor effect of cinnamon extracts is directly linked with enhanced pro-apoptotic activity and inhibition of NFκB and AP1 activities and their target genes in vitro and in vivo mouse melanoma model. Hence, further elucidation of active components of cinnamon extract could lead to development of potent anti-tumor agent or complementary and alternative medicine for the treatment of

  4. Inhibition of Mouse Breast Tumor-Initiating Cells by Calcitriol and Dietary Vitamin D.

    PubMed

    Jeong, Youngtae; Swami, Srilatha; Krishnan, Aruna V; Williams, Jasmaine D; Martin, Shanique; Horst, Ronald L; Albertelli, Megan A; Feldman, Brian J; Feldman, David; Diehn, Maximilian

    2015-08-01

    The anticancer actions of vitamin D and its hormonally active form, calcitriol, have been extensively documented in clinical and preclinical studies. However, the mechanisms underlying these actions have not been completely elucidated. Here, we examined the effect of dietary vitamin D and calcitriol on mouse breast tumor-initiating cells (TICs, also known as cancer stem cells). We focused on MMTV-Wnt1 mammary tumors, for which markers for isolating TICs have previously been validated. We confirmed that these tumors expressed functional vitamin D receptors and estrogen receptors (ER) and exhibited calcitriol-induced molecular responses including ER downregulation. Following orthotopic implantation of MMTV-Wnt1 mammary tumor cells into mice, calcitriol injections or a vitamin D-supplemented diet caused a striking delay in tumor appearance and growth, whereas a vitamin D-deficient diet accelerated tumor appearance and growth. Calcitriol inhibited TIC tumor spheroid formation in a dose-dependent manner in primary cultures and inhibited TIC self-renewal in secondary passages. A combination of calcitriol and ionizing radiation inhibited spheroid formation more than either treatment alone. Further, calcitriol significantly decreased TIC frequency as evaluated by in vivo limiting dilution analyses. Calcitriol inhibition of TIC spheroid formation could be overcome by the overexpression of β-catenin, suggesting that the inhibition of Wnt/β-catenin pathway is an important mechanism mediating the TIC inhibitory activity of calcitriol in this tumor model. Our findings indicate that vitamin D compounds target breast TICs reducing tumor-initiating activity. Our data also suggest that combining vitamin D compounds with standard therapies may enhance anticancer activity and improve therapeutic outcomes. PMID:25934710

  5. 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. PMID:27133052

  6. Protein Phosphatase 2A Inhibition with LB100 Enhances Radiation-Induced Mitotic Catastrophe and Tumor Growth Delay in Glioblastoma.

    PubMed

    Gordon, Ira K; Lu, Jie; Graves, Christian A; Huntoon, Kristin; Frerich, Jason M; Hanson, Ryan H; Wang, Xiaoping; Hong, Christopher S; Ho, Winson; Feldman, Michael J; Ikejiri, Barbara; Bisht, Kheem; Chen, Xiaoyuan S; Tandle, Anita; Yang, Chunzhang; Arscott, W Tristram; Ye, Donald; Heiss, John D; Lonser, Russell R; Camphausen, Kevin; Zhuang, Zhengping

    2015-07-01

    Protein phosphatase 2A (PP2A) is a tumor suppressor whose function is lost in many cancers. An emerging, though counterintuitive, therapeutic approach is inhibition of PP2A to drive damaged cells through the cell cycle, sensitizing them to radiotherapy. We investigated the effects of PP2A inhibition on U251 glioblastoma cells following radiation treatment in vitro and in a xenograft mouse model in vivo. Radiotherapy alone augmented PP2A activity, though this was significantly attenuated with combination LB100 treatment. LB100 treatment yielded a radiation dose enhancement factor of 1.45 and increased the rate of postradiation mitotic catastrophe at 72 and 96 hours. Glioblastoma cells treated with combination LB100 and radiotherapy maintained increased γ-H2AX expression at 24 hours, diminishing cellular repair of radiation-induced DNA double-strand breaks. Combination therapy significantly enhanced tumor growth delay and mouse survival and decreased p53 expression 3.68-fold, compared with radiotherapy alone. LB100 treatment effectively inhibited PP2A activity and enhanced U251 glioblastoma radiosensitivity in vitro and in vivo. Combination treatment with LB100 and radiation significantly delayed tumor growth, prolonging survival. The mechanism of radiosensitization appears to be related to increased mitotic catastrophe, decreased capacity for repair of DNA double-strand breaks, and diminished p53 DNA-damage response pathway activity. PMID:25939762

  7. CDC42 inhibition suppresses progression of incipient intestinal tumors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  8. 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. PMID:24051192

  9. Regulation of microtubule dynamics by DIAPH3 influences amoeboid tumor cell mechanics and sensitivity to taxanes

    PubMed Central

    Morley, Samantha; You, Sungyong; Pollan, Sara; Choi, Jiyoung; Zhou, Bo; Hager, Martin H.; Steadman, Kenneth; Spinelli, Cristiana; Rajendran, Kavitha; Gertych, Arkadiusz; Kim, Jayoung; Adam, Rosalyn M.; Yang, Wei; Krishnan, Ramaswamy; Knudsen, Beatrice S.; Di Vizio, Dolores; Freeman, Michael R.

    2015-01-01

    Taxanes are widely employed chemotherapies for patients with metastatic prostate and breast cancer. Here, we show that loss of Diaphanous-related formin-3 (DIAPH3), frequently associated with metastatic breast and prostate cancers, correlates with increased sensitivity to taxanes. DIAPH3 interacted with microtubules (MT), and its loss altered several parameters of MT dynamics as well as decreased polarized force generation, contractility, and response to substrate stiffness. Silencing of DIAPH3 increased the cytotoxic response to taxanes in prostate and breast cancer cell lines. Analysis of drug activity for tubulin-targeted agents in the NCI-60 cell line panel revealed a uniform positive correlation between reduced DIAPH3 expression and drug sensitivity. Low DIAPH3 expression correlated with improved relapse-free survival in breast cancer patients treated with chemotherapeutic regimens containing taxanes. Our results suggest that inhibition of MT stability arising from DIAPH3 downregulation enhances susceptibility to MT poisons, and that the DIAPH3 network potentially reports taxane sensitivity in human tumors. PMID:26179371

  10. Inhibition of cytokine production by a tumor cell product.

    PubMed Central

    Farram, E; Nelson, M; Nelson, D S; Moon, D K

    1982-01-01

    Supernatants from cultured mouse and human tumour cells, but not mouse or guinea-pig fibroblasts, inhibited the production of a lymphokine, macrophage chemotactic factor, by PHA-stimulated mouse spleen cells. The supernatants affected spleen cells from old, but not young, mice. They were most active if added at the start of the spleen cell culture and did not act by binding phytohaemagglutinin (PHA). The active material had an approximate molecular weight, on membrane filtration, of 1000-10,000 and could be bound to and eluted from Con A-Sepharose. Tumour supernatant factor(s) of similar molecular weight inhibited the production of interleukin 1 (lymphocyte activating factor) in response to lipopolysaccharide by stimulated thioglycollate-induced peritoneal exudate macrophages, but not by Corynebacterium parvum-activated macrophages. Similar tumour-produced material has been found to inhibit the early phase of delayed-type hypersensitivity reactions in older mice. It is suggested that this effect is due, at least in part, to inhibition of interleukin 1 production leading to inhibition of lymphokine production. PMID:7047385

  11. Telomerase antagonists GRN163 and GRN163L inhibit tumor growth and increase chemosensitivity of human hepatoma.

    PubMed

    Djojosubroto, Meta W; Chin, Allison C; Go, Ning; Schaetzlein, Sonja; Manns, Michael P; Gryaznov, Sergei; Harley, Calvin B; Rudolph, K Lenhard

    2005-11-01

    Most cancer cells have an immortal growth capacity as a consequence of telomerase reactivation. Inhibition of this enzyme leads to increased telomere dysfunction, which limits the proliferative capacity of tumor cells; thus, telomerase inhibition represents a potentially safe and universal target for cancer treatment. We evaluated the potential of two thio-phosphoramidate oligonucleotide inhibitors of telomerase, GRN163 and GRN163L, as drug candidates for the treatment of human hepatoma. GRN163 and GRN163L were tested in preclinical studies using systemic administration to treat flank xenografts of different human hepatoma cell lines (Hep3B and Huh7) in nude mice. The studies showed that both GRN163 and GRN163L inhibited telomerase activity and tumor cell growth in a dose-dependent manner in vitro and in vivo. The potency and efficacy of the lipid-conjugated antagonist, GRN163L, was superior to the nonlipidated parent compound, GRN163. Impaired tumor growth in vivo was associated with critical telomere shortening, induction of telomere dysfunction, reduced rate of cell proliferation, and increased apoptosis in the treatment groups. In vitro, GRN163L administration led to higher prevalence of chromosomal telomere-free ends and DNA damage foci in both hepatoma cell lines. In addition, in vitro chemosensitivity assay showed that pretreatment with GRN163L increased doxorubicin sensitivity of Hep3B. In conclusion, our data support the development of GRN163L, a novel lipidated conjugate of the telomerase inhibitor GRN163, for systemic treatment of human hepatoma. In addition to limiting the proliferative capacity of hepatoma, GRN163L might also increase the sensitivity of this tumor type to conventional chemotherapy. PMID:16114043

  12. Sensitivity of Small Cell Lung Cancer to BET Inhibition Is Mediated by Regulation of ASCL1 Gene Expression.

    PubMed

    Lenhart, Ryan; Kirov, Stefan; Desilva, Heshani; Cao, Jian; Lei, Ming; Johnston, Kathy; Peterson, Russell; Schweizer, Liang; Purandare, Ashok; Ross-Macdonald, Petra; Fairchild, Craig; Wong, Tai; Wee, Susan

    2015-10-01

    The BET (bromodomain and extra-terminal) proteins bind acetylated histones and recruit protein complexes to promote transcription elongation. In hematologic cancers, BET proteins have been shown to regulate expression of MYC and other genes that are important to disease pathology. Pharmacologic inhibition of BET protein binding has been shown to inhibit tumor growth in MYC-dependent cancers, such as multiple myeloma. In this study, we demonstrate that small cell lung cancer (SCLC) cells are exquisitely sensitive to growth inhibition by the BET inhibitor JQ1. JQ1 treatment has no impact on MYC protein expression, but results in downregulation of the lineage-specific transcription factor ASCL1. SCLC cells that are sensitive to JQ1 are also sensitive to ASCL1 depletion by RNAi. Chromatin immunoprecipitation studies confirmed the binding of the BET protein BRD4 to the ASCL1 enhancer, and the ability of JQ1 to disrupt the interaction. The importance of ASCL1 as a potential driver oncogene in SCLC is further underscored by the observation that ASCL1 is overexpressed in >50% of SCLC specimens, an extent greater than that observed for other putative oncogenes (MYC, MYCN, and SOX2) previously implicated in SCLC. Our studies have provided a mechanistic basis for the sensitivity of SCLC to BET inhibition and a rationale for the clinical development of BET inhibitors in this disease with high unmet medical need. PMID:26253517

  13. 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. PMID:27350172

  14. Thymic stromal lymphopoietin (TSLP) inhibits human colon tumor growth by promoting apoptosis of tumor cells

    PubMed Central

    Yang, Xuguang; Li, Bingji; Liu, Jie; He, Rui

    2016-01-01

    Thymic stromal lymphopoietin (TSLP) has recently been suggested in several epithelial cancers, either pro-tumor or anti-tumor. However, the role of TSLP in colon cancer remains unknown. We here found significantly decreased TSLP levels in tumor tissues compared with tumor-surrounding tissues of patients with colon cancer and TSLP levels negatively correlated with the clinical staging score of colon cancer. TSLPR, the receptor of TSLP, was expressed in all three colon cancer cell lines investigated and colon tumor tissues. The addition of TSLP significantly enhanced apoptosis of colon cancer cells in a TSLPR-dependent manner. Interestingly, TSLP selectively induced the apoptosis of colon cancer cells, but not normal colonic epithelial cells. Furthermore, we demonstrated that TSLP induced JNK and p38 activation and initiated apoptosis mainly through the extrinsic pathway, as caspase-8 inhibitor significantly reversed the apoptosis-promoting effect of TSLP. Finally, using a xenograft mouse model, we demonstrated that peritumoral administration of TSLP greatly reduced tumor growth accompanied with extensive tumor apoptotic response, which was abolished by tumor cell-specific knockdown of TSLPR. Collectively, our study reveals a novel anti-tumor effect of TSLP via direct promotion of the apoptosis of colon cancer cells, and suggests that TSLP could be of value in treating colon cancer. PMID:26919238

  15. 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.

  16. 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.

  17. Selective Tumor Cell Inhibition Effect of Ni-Ti Layered Double Hydroxides Thin Films Driven by the Reversed pH Gradients of Tumor Cells.

    PubMed

    Wang, Donghui; Ge, Naijian; Li, Jinhua; Qiao, Yuqin; Zhu, Hongqin; Liu, Xuanyong

    2015-04-22

    Nitinol is widely fabricated as stents for the palliation treatment of many kinds of cancers. It is of great importance to develop nitinol stents with selective tumor cell inhibition effects. In this work, a series of pH sensitive films composed of Ni(OH)2 and Ni-Ti layered double hydroxide (Ni-Ti LDH) with different Ni/Ti ratios were prepared on the surface of nitinol via hydrothermal treatment. The films with specific Ni/Ti ratios would release a large amount of nickel ions under acidic environments but were relatively stable in neutral or weak alkaline medium. Cell viability tests showed that the films can effectively inhibit the growth of cancer cells but have little adverse effects to normal cells. Besides, extraordinarily high intracellular nickel content and reactive oxygen species (ROS) level were found in cancer cells, indicating the death of cancer cells may be induced by the excessive intake of nickel ions. Such selective cancer cell inhibition effect of the films is supposed to relate with the reversed pH gradients of tumor cells. PMID:25825800

  18. 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

  19. ZBTB16: a novel sensitive and specific biomarker for yolk sac tumor.

    PubMed

    Xiao, Guang-Qian; Li, Faqian; Unger, Pamela D; Katerji, Hani; Yang, Qi; McMahon, Loralee; Burstein, David E

    2016-06-01

    Although the function of zinc finger and BTB domain containing 16 (ZBTB16) in spermatogenesis is well documented, expression of ZBTB16 in germ cell tumors has not yet been studied. The aim of this study was to investigate the immunohistochemical expression and diagnostic utility of ZBTB16 in germ cell tumors. A total of 67 adult germ cell tumors were studied (62 testicular germ cell tumors, 2 ovarian yolk sac tumors, 1 mediastinal yolk sac tumor, and 2 retroperitoneal metastatic yolk sac tumors). The 62 testicular primary germ cell tumors are as follows: 34 pure germ cell tumors (20 seminomas, 8 embryonal carcinomas, 2 teratomas, 1 choriocarcinoma, 1 carcinoid, and 2 spermatocytic tumors) and 28 mixed germ cell tumors (composed of 13 embryonal carcinomas, 15 yolk sac tumors, 15 teratomas, 7 seminomas, and 3 choriocarcinomas in various combinations). Thirty-five cases contained germ cell neoplasia in situ. Yolk sac tumor was consistently reactive for ZBTB16. Among the 15 testicular yolk sac tumors in mixed germ cell tumors, all displayed moderate to diffuse ZBTB16 staining. ZBTB16 reactivity was present regardless of the histologic patterns of yolk sac tumor and ZBTB16 was able to pick up small foci of yolk sac tumor intermixed/embedded in other germ cell tumor subtype elements. Diffuse ZBTB16 immunoreactivity was also observed in 2/2 metastatic yolk sac tumors, 1/1 mediastinal yolk sac tumor, 2/2 ovarian yolk sac tumors, 2/2 spermatocytic tumors, 1/1 carcinoid, and the spermatogonial cells. All the other non-yolk sac germ cell tumors were nonreactive, including seminoma (n=27), embryonal carcinoma (n=21), teratoma (n=17), choriocarcinoma (n=4), and germ cell neoplasia in situ (n=35). The sensitivity and specificity of ZBTB16 in detecting yolk sac tumor among the germ cell tumors was 100% (20/20) and 96% (66/69), respectively. In conclusion, ZBTB16 is a highly sensitive and specific marker for yolk sac tumor. PMID:26916077

  20. MMP2-Sensitive PEG-Lipid Copolymers: A New Type of Tumor-Targeted P-Glycoprotein Inhibitor.

    PubMed

    Dai, Zhi; Yao, Qing; Zhu, Lin

    2016-05-25

    Low tumor targetability and multidrug resistance (MDR) are two major impediments to the success of cancer treatments. Nanomaterials which possess high tumor targetability and the ability to reverse the MDR are rare. This report describes a new type of self-assembling polyethylene glycol-phosphoethanolamine-based copolymers (PEG-pp-PE) which showed both the matrix metalloproteinase 2 (MMP2)-sensitive tumor-targeted drug delivery and ability to inhibit the P-glycoprotein (P-gp)-mediated drug efflux. In this study, we synthesized a series of the homologous analogues of PEG-pp-PE copolymers and investigated the influence of their structures, including PEG lengths and peptide linkers, on the drug efflux, and identified the underlying mechanisms. We found that the whole structure (PEG-peptide-lipid) rather than any parts of the copolymers was key for the P-gp inhibition and a delicate balance between the hydrophilic and lipophilic segments of the PEG-pp-PE copolymers was needed for better modulating the P-gp-mediated drug efflux. The best copolymer, PEG2k-pp-PE, showed even higher P-gp inhibition effect than the d-α-tocopherol polyethylene glycol 1000 succinate (TPGS1k). We also found that the P-gp inhibition capability of PEG-pp-PE copolymers was highly associated with the P-gp down-regulation, the increase in the plasma membrane fluidity, and the inhibition of the P-gp ATPase activity. Besides, the excellent physicochemical properties, high drug loading, MMP2-dependent drug release, and improved drug efficacy in the MDR cancer cells suggested that the PEG-pp-PE copolymers might have great potential for building tumor-targeted drug delivery systems for treating drug-resistant cancers. PMID:27145021

  1. Inhibition of PI3K/BMX Cell Survival Pathway Sensitizes to BH3 Mimetics in SCLC.

    PubMed

    Potter, Danielle S; Galvin, Melanie; Brown, Stewart; Lallo, Alice; Hodgkinson, Cassandra L; Blackhall, Fiona; Morrow, Christopher J; Dive, Caroline

    2016-06-01

    Most small cell lung cancer (SCLC) patients are initially responsive to cytotoxic chemotherapy, but almost all undergo fatal relapse with progressive disease, highlighting an urgent need for improved therapies and better patient outcomes in this disease. The proapoptotic BH3 mimetic ABT-737 that targets BCL-2 family proteins demonstrated good single-agent efficacy in preclinical SCLC models. However, so far clinical trials of the BH3 mimetic Navitoclax have been disappointing. We previously demonstrated that inhibition of a PI3K/BMX cell survival signaling pathway sensitized colorectal cancer cells to ABT-737. Here, we show that SCLC cell lines, which express high levels of BMX, become sensitized to ABT-737 upon inhibition of PI3K in vitro, and this is dependent on inhibition of the PI3K-BMX-AKT/mTOR signaling pathway. Consistent with these cell line data, when combined with Navitoclax, PI3K inhibition suppressed tumor growth in both an established SCLC xenograft model and in a newly established circulating tumor cell-derived explant (CDX) model generated from a blood sample obtained at presentation from a chemorefractory SCLC patient. These data show for the first time that a PI3K/BMX signaling pathway plays a role in SCLC cell survival and that a BH3 mimetic plus PI3K inhibition causes prolonged tumor regression in a chemorefractory SCLC patient-derived model in vivo These data add to a body of evidence that this combination should move toward the clinic. Mol Cancer Ther; 15(6); 1248-60. ©2016 AACR. PMID:27197306

  2. Temporal mTOR inhibition protects Fbxw7-deficient mice from radiation-induced tumor development

    PubMed Central

    Liu, Yueyong; Huang, Yurong; Wang, Zeran; Huang, Yong; Li, Xiaohua; Louie, Alexander; Wei, Guangwei; Mao, Jian-Hua

    2013-01-01

    FBXW7 acts as a tumor suppressor in numerous types of human cancers through ubiquitination of different oncoproteins including mTOR. However, how the mutation/loss of Fbxw7 results in tumor development remains largely unknown. Here we report that downregulation of mTOR by radiation is Fbxw7-dependent, and short-term mTOR inhibition by rapamycin after exposure to radiation significantly postpones tumor development in Fbxw7/p53 double heterozygous (Fbxw7+/−p53+/−) mice but not in p53 single heterozygous (p53+/−) mice. Tumor latency of rapamycin treated Fbxw7+/−p53+/− mice is remarkably similar to those of p53+/− mice while placebo treated Fbxw7+/−p53+/− mice develop tumor significantly earlier than placebo treated p53+/− mice. Furthermore, we surprisingly find that, although temporal treatment of rapamycin is given at a young age, the inhibition of mTOR activity sustainably remains in tumors. These results indicate that inhibition of mTOR signaling pathway suppresses the contribution of Fbxw7 loss toward tumor development. PMID:23454868

  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. Evaluation of Elephantopus scaber on the inhibition of chemical carcinogenesis and tumor development in mice.

    PubMed

    Geetha, B S; Latha, P G; Remani, P

    2010-03-01

    The effect of the active fraction of Elephantopus scaber L. (Asteraceae) (ES) on skin papillomas induced by 7,12-dimethylbenz(a)anthracene (DMBA) as an initiator and croton oil as promoter was studied in mice. The active fraction of E. scaber (100 mg/kg) on topical application delayed the onset of papilloma formation and reduced the mean number of papillomas and the mean weight of papillomas per mouse. The intraperitoneal administration of the active fraction of E. scaber also had a significant effect on subcutaneous injection of 20-methylcholanthrene (20-MCA)-induced soft tissue sarcomas in mice. It inhibited the incidence of sarcomas and reduced the tumor diameter compared to MCA-treated control animals. The subcutaneous administration of the active fraction of E. scaber significantly inhibited the growth of subcutaneously transplanted DLA and EAC solid tumors, delayed the onset of tumor formation, and increased the life span of tumor bearing mice. The present study thus indicates the tumor inhibitory activity of the active fraction of E. scaber against chemically induced tumors and its ability to inhibit the development of solid tumors. PMID:20645824

  5. Multiwalled Carbon Nanotubes Inhibit Tumor Progression in a Mouse Model.

    PubMed

    García-Hevia, Lorena; Villegas, Juan C; Fernández, Fidel; Casafont, Íñigo; González, Jesús; Valiente, Rafael; Fanarraga, Mónica L

    2016-05-01

    Understanding the molecular mechanisms underlying the biosynthetic interactions between particular nanomaterials with specific cells or proteins opens new alternatives in nanomedicine and nanotoxicology. Multiwalled carbon nanotubes (MWCNTs) have long been explored as drug delivery systems and nanomedicines against cancer. There are high expectations for their use in therapy and diagnosis. These filaments can translocate inside cultured cells and intermingle with the protein nanofilaments of the cytoskeleton, interfering with the biomechanics of cell division mimicking the effect of traditional microtubule-binding anti-cancer drugs such as paclitaxel. Here, it is shown how MWCNTs can trigger significant anti-tumoral effects in vivo, in solid malignant melanomas produced by allograft transplantation. Interestingly, the MWCNT anti-tumoral effects are maintained even in solid melanomas generated from paclitaxel-resistant cells. These findings provide great expectation in the development of groundbreaking adjuvant synthetic microtubule-stabilizing chemotherapies to overcome drug resistance in cancer. PMID:26866927

  6. Squalamine inhibits angiogenesis and solid tumor growth in vivo and perturbs embryonic vasculature.

    PubMed

    Sills, A K; Williams, J I; Tyler, B M; Epstein, D S; Sipos, E P; Davis, J D; McLane, M P; Pitchford, S; Cheshire, K; Gannon, F H; Kinney, W A; Chao, T L; Donowitz, M; Laterra, J; Zasloff, M; Brem, H

    1998-07-01

    The novel aminosterol, squalamine, inhibits angiogenesis and tumor growth in multiple animal models. This effect is mediated, at least in part, by blocking mitogen-induced proliferation and migration of endothelial cells, thus preventing neovascularization of the tumor. Squalamine has no observable effect on unstimulated endothelial cells, is not directly cytotoxic to tumor cells, does not alter mitogen production by tumor cells, and has no obvious effects on the growth of newborn vertebrates. Squalamine was also found to have remarkable effects on the primitive vascular bed of the chick chorioallantoic membrane, which has striking similarities to tumor capillaries. Squalamine may thus be well suited for treatment of tumors and other diseases characterized by neovascularization in humans. PMID:9661892

  7. 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.

  8. 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. PMID

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

    PubMed Central

    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.

    2015-01-01

    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. PMID

  10. 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. Mol Cancer Ther; 15(3); 460-70. ©2016 AACR. PMID:26832797

  11. Polyphenols in brewed green tea inhibit prostate tumor xenograft growth by localizing to the tumor and decreasing oxidative stress and angiogenesis.

    PubMed

    Henning, Susanne M; Wang, Piwen; Said, Jonathan; Magyar, Clara; Castor, Brandon; Doan, Ngan; Tosity, Carmen; Moro, Aune; Gao, Kun; Li, Luyi; Heber, David

    2012-11-01

    It has been demonstrated in various animal models that the oral administration of green tea (GT) extracts in drinking water can inhibit tumor growth, but the effects of brewed GT on factors promoting tumor growth, including oxidant damage of DNA and protein, angiogenesis and DNA methylation, have not been tested in an animal model. To explore these potential mechanisms, brewed GT was administered instead of drinking water to male severe combined immunodeficiency (SCID) mice with androgen-dependent human LAPC4 prostate cancer cell subcutaneous xenografts. Tumor volume was decreased significantly in mice consuming GT, and tumor size was significantly correlated with GT polyphenol (GTP) content in tumor tissue. There was a significant reduction in hypoxia-inducible factor 1-alpha and vascular endothelial growth factor protein expression. GT consumption significantly reduced oxidative DNA and protein damage in tumor tissue as determined by 8-hydroxydeoxyguanosine/deoxyguanosine ratio and protein carbonyl assay, respectively. Methylation is known to inhibit antioxidative enzymes such as glutathione S-transferase pi to permit reactive oxygen species promotion of tumor growth. GT inhibited tumor 5-cytosine DNA methyltransferase 1 mRNA and protein expression significantly, which may contribute to the inhibition of tumor growth by reactivation of antioxidative enzymes. This study advances our understanding of tumor growth inhibition by brewed GT in an animal model by demonstrating tissue localization of GTPs in correlation with inhibition of tumor growth. Our results suggest that the inhibition of tumor growth is due to GTP-mediated inhibition of oxidative stress and angiogenesis in the LAPC4 xenograft prostate tumor in SCID mice. PMID:22405694

  12. cdk4 Deficiency Inhibits Skin Tumor Development but Does Not Affect Normal Keratinocyte Proliferation

    PubMed Central

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

    2002-01-01

    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. PMID:12163365

  13. 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

  14. N-(3-oxo-acyl) homoserine lactone inhibits tumor growth independent of Bcl-2 proteins

    PubMed Central

    Zhao, Guoping; Neely, Aaron M.; Schwarzer, Christian; Lu, Huayi; Whitt, Aaron G.; Stivers, Nicole S.; Burlison, Joseph A.; White, Carl; Machen, Terry E.; Li, Chi

    2016-01-01

    Pseudomonas aeruginosa produces N-(3-oxododecanoyl)-homoserine lactone (C12) as a quorum-sensing molecule for bacterial communication. C12 has also been reported to induce apoptosis in various types of tumor cells. However, the detailed molecular mechanism of C12-triggerred tumor cell apoptosis is still unclear. In addition, it is completely unknown whether C12 possesses any potential therapeutic effects in vivo. Our data indicate that, unlike most apoptotic inducers, C12 evokes a novel form of apoptosis in tumor cells through inducing mitochondrial membrane permeabilization independent of both pro- and anti-apoptotic Bcl-2 proteins. Importantly, C12 inhibits tumor growth in animals regardless of either pro- or anti-apoptotic Bcl-2 proteins. Furthermore, opposite to conventional chemotherapeutics, C12 requires paraoxonase 2 (PON2) to exert its cytotoxicity on tumor cells in vitro and its inhibitory effects on tumor growth in vivo. Overall, our results demonstrate that C12 inhibits tumor growth independent of both pro- and anti-apoptotic Bcl-2 proteins, and through inducing unique apoptotic signaling mediated by PON2 in tumor cells. PMID:26758417

  15. N-(3-oxo-acyl) homoserine lactone inhibits tumor growth independent of Bcl-2 proteins.

    PubMed

    Zhao, Guoping; Neely, Aaron M; Schwarzer, Christian; Lu, Huayi; Whitt, Aaron G; Stivers, Nicole S; Burlison, Joseph A; White, Carl; Machen, Terry E; Li, Chi

    2016-02-01

    Pseudomonas aeruginosa produces N-(3-oxododecanoyl)-homoserine lactone (C12) as a quorum-sensing molecule for bacterial communication. C12 has also been reported to induce apoptosis in various types of tumor cells. However, the detailed molecular mechanism of C12-triggerred tumor cell apoptosis is still unclear. In addition, it is completely unknown whether C12 possesses any potential therapeutic effects in vivo. Our data indicate that, unlike most apoptotic inducers, C12 evokes a novel form of apoptosis in tumor cells through inducing mitochondrial membrane permeabilization independent of both pro- and anti-apoptotic Bcl-2 proteins. Importantly, C12 inhibits tumor growth in animals regardless of either pro- or anti-apoptotic Bcl-2 proteins. Furthermore, opposite to conventional chemotherapeutics, C12 requires paraoxonase 2 (PON2) to exert its cytotoxicity on tumor cells in vitro and its inhibitory effects on tumor growth in vivo. Overall, our results demonstrate that C12 inhibits tumor growth independent of both pro- and anti-apoptotic Bcl-2 proteins, and through inducing unique apoptotic signaling mediated by PON2 in tumor cells. PMID:26758417

  16. 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.

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

    PubMed

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

    2016-07-01

    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

  18. 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

  19. Tumor cell responses to inhibition of thymidylate synthase

    SciTech Connect

    Keyomarsi, K.

    1989-01-01

    The cellular, biochemical and molecular events that occur in tumor cells treated with inhibitors of thymidylate synthase (TS) were studied. 5-Fluorouracil (5-FUra) and fluorodeoxyuridine (FdUrd) are more growth inhibitory to mouse and human tumor cells when grown in medium containing folinate. L1210 cells exposed to folinate and noncytotoxic concentrations of 5-FUra or FdUrd, resulted in a 98% to 99.98% cell kill. Exposure of L1210 cells to folinate resulted in expansion of intracellular pools of 5,10-methylenetetrahydrofolate, delayed the reappearance of catalytically active TS following FdUrd exposure, and stabilized inactive TS complexes over the same concentration range that augmented the cytotoxic effect of FdUrd and 5-FUra. In intact L1210 cells, fluorodeoxyuridylate (FdUMP) behaved as an inhibitor whose complexes with TS dissociate with a biologically significant rate. However, these complexes become functionally irreversible in cells incubated with high levels of folinate. CB 3717 eliminated TS activity in L1210 cells, yet the inactive enzyme retained the ability to bind ({sup 3}H)-FdUMP covalently, suggesting that the binding of one subunit of TS inactivates the catalytic activity of both subunits.

  20. 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.

  1. Improved sensitivity in the diagnosis of gastro-intestinal tumors by fuzzy logic-based tumor marker profiles including the tumor M2-PK.

    PubMed

    Schneider, Joachim; Bitterlich, Norman; Schulze, Guntram

    2005-01-01

    The aim of this study was to improve diagnostic efficiency in the detection of gastro-intestinal cancers by using fuzzy logic modeling in combination with a tumor marker panel (CEA, CA72-4, CA19-9) including Tumor M2-PK. In this prospective study histologically confirmed colorectal (n=247), esophageal (n=86) and gastric cancer (n=122) patients were investigated and compared to control (n=53) persons without any malignant diseases. Tumor M2-PK was measured in plasma with an ELISA (ScheBoBiotech, Germany); all other markers were measured in sera (Roche, Germany). At 95% specificity, tumor detection was possible by the best single marker in colorectal cancer patients in 48% (Tumor M2-PK), in gastric cancers in 61% (CA72-4) and in esophageal cancers in 56% (Tumor M2-PK). A fuzzy logic rule-based system employing a tumor marker panel increased sensitivity significantly in colorectal cancers (p<0. 001) to 63% (Tumor M2-PK and CEA), in gastric cancers (p<0.001) to 81% (Tumor M2-PK and CA 72-4) and in esophageal cancers (p<0.02) to 74% (Tumor M2-PK and CA72-4). Adding a third marker further improved the sensitivity only marginally. Fuzzy logic analysis has proven to be more powerful than measurement of single markers alone or combinations using multiple logistic regression analysis of the markers. Therefore, with the fuzzy logic method and a tumor marker panel (including Tumor M2-PK), a new diagnostic tool for the detection of gastro-intestinal cancers is available. PMID:16033052

  2. Downregulation of tetrahydrobiopterin inhibits tumor angiogenesis in BALB/c-nu mice with hepatocellular carcinoma

    PubMed Central

    Dai, Youguo; Cui, Jin; Gan, Ping; Li, Weiming

    2016-01-01

    Hepatocellular carcinoma (HCC) is a highly vascular tumor, and treatment options for patients of advanced-stage are limited. Nitric oxide (NO), which is derived from endothelial nitric oxide synthase (eNOS), provides crucial signals for angiogenesis in the tumor microenvironment. Tetrahydrobiopterin (BH4) is an essential cofactor eNOS and represents a critical determinant of NO production. To examine whether treatment of 2,4-diamino-6-hydroxypyrimidine (DAHP) inhibits angiogenesis of HCC, BALB/c-nu mice were injected with HepG-2 cells with DAHP. Supplemental DAHP treatment decreased K-ras mRNA transcripts, inhibition of phosphorylation of eNOS and Akt, inhibition of guanosine triphosphate cyclohydrolase (GTPCH), and decreased significantly NO synthesis, and then inhibited angiogenesis, compared with the results observed in the saline group. Histopathology demonstrated angiogenesis and tumor formation were significantly inhibited in HCC. DAHP downregulates GTPCH protein expression, corresponding to decreased levels of BH4 and the contents of NO. In addition, DAHP downregulates eNOS and Akt protein expression, corresponding to decreased eNOS phosphorylation at Ser1177 and Akt phosphorylation, compared with the saline control. We suggest that DAHP, recognized as a specific competitive inhibitor of GTPCH, can decrease tumor BH4 and NO by the inhibition of the wild-type Ras-PI3K/Akt pathway, and then inhibiting angiogenesis, and may provide a novel and promising way to target BH4 synthetic pathways to inhibit angiogenesis and to control potential progression of HCC. Whether DAHP has a therapeutic potential will require more direct testing in humans. PMID:27279530

  3. 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.

  4. TGFβ Induces ‘BRCAness’ and Sensitivity to PARP Inhibition in Breast Cancer by Regulating DNA Repair Genes

    PubMed Central

    Liu, Liang; Zhou, Weiying; Cheng, Chun-Ting; Ren, Xiubao; Somlo, George; Fong, Miranda Y.; Chin, Andrew R.; Li, Hui; Yu, Yang; Xu, Yang; O'Connor, Sean Timothy Francis; O'Connor, Timothy R.; Ann, David K.; Stark, Jeremy M.; Wang, Shizhen Emily

    2014-01-01

    Transforming growth factor β (TGFβ) proteins are multitasking cytokines, whose high levels at tumor sites generally correlate with poor prognosis in human cancer patients. Previously it was reported that TGFβ downregulates the expression of ataxia telangiectasia mutated (ATM) and mutS homolog 2 (MSH2) in breast cancer (BC) cells through a miRNA-mediated mechanism. In this study, expression of a panel of DNA repair genes was examined, identifying breast cancer 1, early onset (BRCA1) as a target downregulated by TGFβ through the miR-181 family. Correlations between the expression levels of TGFβ1 and the miR-181/BRCA1 axis were observed in primary breast tumor specimens. By downregulating BRCA1, ATM, and MSH2, TGFβ orchestrates DNA damage response (DDR) in certain BC cells to induce a ‘BRCAness’ phenotype, including impaired DNA repair efficiency and synthetic lethality to the inhibition of poly (ADP-ribose) polymerase (PARP). Xenograft tumors with active TGFβ signaling exhibited resistance to the DNA-damaging agent doxorubicin but increased sensitivity to the PARP inhibitor ABT-888. Combination of doxorubicin with ABT-888 significantly improved the treatment efficacy in TGFβ-active tumors. Thus, TGFβ can induce ‘BRCAness’ in certain BCs carrying wild-type BRCA genes and enhance the responsiveness to PARP inhibition, and the molecular mechanism behind this is characterized. Implications: These findings enable better selection of sporadic breast cancer patients for PARP interventions, which have exhibited beneficial effects in patients carrying BRCA mutations. PMID:25103497

  5. Radiosensitization by PARP Inhibition in DNA Repair Proficient and Deficient Tumor Cells: Proliferative Recovery in Senescent Cells.

    PubMed

    Alotaibi, Moureq; Sharma, Khushboo; Saleh, Tareq; Povirk, Lawrence F; Hendrickson, Eric A; Gewirtz, David A

    2016-03-01

    Radiotherapy continues to be a primary modality in the treatment of cancer. In addition to promoting apoptosis, radiation-induced DNA damage can promote autophagy and senescence, both of which can theoretically function to prolong tumor survival. In this work, we tested the hypothesis that autophagy and/or senescence could be permissive for DNA repair, thereby facilitating tumor cell recovery from radiation-induced growth arrest and/or cell death. In addition, studies were designed to elucidate the involvement of autophagy and senescence in radiosensitization by PARP inhibitors and the re-emergence of a proliferating tumor cell population. In the context of this work, the relationship between radiation-induced autophagy and senescence was also determined. Studies were performed using DNA repair-proficient HCT116 colon carcinoma cells and a repair-deficient ligase IV(-/-) isogenic cell line. Exposure to radiation promoted a parallel induction of autophagy and senescence that was strongly correlated with the extent of persistent H2AX phosphorylation in both cell lines, however, inhibition of autophagy failed to suppress senescence, indicating that the two responses were dissociable. Exposure to radiation resulted in a transient arrest in the HCT116 cells while arrest was prolonged in the ligase IV(-/-) cells, however, both cell lines ultimately recovered proliferative function, which may reflect maintenance of DNA repair capacity. The PARP inhibitors, olaparib and niraparib, increased the extent of persistent DNA damage induced by radiation exposure as well as the extent of both autophagy and senescence. Neither cell line underwent significant apoptosis by radiation exposure alone or in the presence of the PARP inhibitors. Inhibition of autophagy failed to attenuate radiosensitization, indicating that autophagy was not involved in the action of the PARP inhibitors. As with radiation alone, despite sensitization by PARP inhibition, proliferative recovery was evident

  6. Silibinin inhibits accumulation of myeloid-derived suppressor cells and tumor growth of murine breast cancer.

    PubMed

    Forghani, Parvin; Khorramizadeh, Mohammad R; Waller, Edmund K

    2014-04-01

    Myeloid-derived suppressor cells (MDSC)s increase in blood and accumulate in the tumor microenvironment of tumor-bearing animals, contributing to immune suppression in cancer. Silibinin, a natural flavonoid from the seeds of milk thistle, has been developed as an anti-inflammatory agent and supportive care agent to reduce the toxicity of cancer chemotherapy. The goals of this study were to evaluate the effect of silibinin on MDSCs in tumor-bearing mice and antitumor activity of silibinin in a mouse model of breast cancer. 4T1 luciferase-transfected mammary carcinoma cells were injected into in the mammary fat pad female BALB/c mice, and female CB17-Prkdc Scid/J mice. Silibinin treatment started on day 4 or day 14 after tumor inoculation continued every other day. Tumor growth was monitored by bioluminescent imaging (BLI) measuring total photon flux. Flow cytometry measured total leukocytes, CD11b(+) Gr-1(+) MDSC, and T cells in the blood and tumors of tumor-bearing mice. The effects of silibinin on 4T1 cell viability in vitro were measured by BLI. Treatment with silibinin increased overall survival in mice harboring tumors derived from the 4T1-luciferase breast cancer cell line, and reduced tumor volumes and numbers of CD11b(+) Gr-1(+) MDSCs in the blood and tumor, and increased the content of T cells in the tumor microenvironment. Silibinin failed to inhibit tumor growth in immunocompromised severe combined immunodeficiency mice, supporting the hypothesis that anticancer effect of silibinin is immune-mediated. The antitumor activity of silibinin requires an intact host immune system and is associated with decreased accumulation of blood and tumor-associated MDSCs. PMID:24574320

  7. Aptamers Binding to c-Met Inhibiting Tumor Cell Migration

    PubMed Central

    Piater, Birgit; Doerner, Achim; Guenther, Ralf; Kolmar, Harald; Hock, Bjoern

    2015-01-01

    The human receptor tyrosine kinase c-Met plays an important role in the control of critical cellular processes. Since c-Met is frequently over expressed or deregulated in human malignancies, blocking its activation is of special interest for therapy. In normal conditions, the c-Met receptor is activated by its bivalent ligand hepatocyte growth factor (HGF). Also bivalent antibodies can activate the receptor by cross linking, limiting therapeutic applications. We report the generation of the RNA aptamer CLN64 containing 2’-fluoro pyrimidine modifications by systematic evolution of ligands by exponential enrichment (SELEX). CLN64 and a previously described single-stranded DNA (ssDNA) aptamer CLN3 exhibited high specificities and affinities to recombinant and cellular expressed c-Met. Both aptamers effectively inhibited HGF-dependent c-Met activation, signaling and cell migration. We showed that these aptamers did not induce c-Met activation, revealing an advantage over bivalent therapeutic molecules. Both aptamers were shown to bind overlapping epitopes but only CLN3 competed with HGF binding to cMet. In addition to their therapeutic and diagnostic potential, CLN3 and CLN64 aptamers exhibit valuable tools to further understand the structural and functional basis for c-Met activation or inhibition by synthetic ligands and their interplay with HGF binding. PMID:26658271

  8. Synergistic tumor suppression by combined inhibition of telomerase and CDKN1A

    PubMed Central

    Gupta, Romi; Dong, Yuying; Solomon, Peter D.; Wettersten, Hiromi I.; Cheng, Christopher J.; Min, JIn-Na; Henson, Jeremy; Dogra, Shaillay Kumar; Hwang, Sung H.; Hammock, Bruce D.; Zhu, Lihua J.; Reddel, Roger R.; Saltzman, W. Mark; Weiss, Robert H.; Chang, Sandy; Green, Michael R.; Wajapeyee, Narendra

    2014-01-01

    Tumor suppressor p53 plays an important role in mediating growth inhibition upon telomere dysfunction. Here, we show that loss of the p53 target gene cyclin-dependent kinase inhibitor 1A (CDKN1A, also known as p21WAF1/CIP1) increases apoptosis induction following telomerase inhibition in a variety of cancer cell lines and mouse xenografts. This effect is highly specific to p21, as loss of other checkpoint proteins and CDK inhibitors did not affect apoptosis. In telomerase, inhibited cell loss of p21 leads to E2F1- and p53-mediated transcriptional activation of p53-upregulated modulator of apoptosis, resulting in increased apoptosis. Combined genetic or pharmacological inhibition of telomerase and p21 synergistically suppresses tumor growth. Furthermore, we demonstrate that simultaneous inhibition of telomerase and p21 also suppresses growth of tumors containing mutant p53 following pharmacological restoration of p53 activity. Collectively, our results establish that inactivation of p21 leads to increased apoptosis upon telomerase inhibition and thus identify a genetic vulnerability that can be exploited to treat many human cancers containing either wild-type or mutant p53. PMID:25024194

  9. The YSNSG cyclopeptide derived from tumstatin inhibits tumor angiogenesis by down-regulating endothelial cell migration.

    PubMed

    Thevenard, Jessica; Ramont, Laurent; Devy, Jérome; Brassart, Bertrand; Dupont-Deshorgue, Aurélie; Floquet, Nicolas; Schneider, Laurence; Ouchani, Farid; Terryn, Christine; Maquart, François-Xavier; Monboisse, Jean-Claude; Brassart-Pasco, Sylvie

    2010-03-01

    We previously demonstrated that the CNYYSNS peptide derived from tumstatin inhibited in vivo tumor progression. The YSNS motif formed a beta-turn crucial for biological activity. More recently, a YSNSG cyclopeptide with a constrained beta-turn on the YSNS residues was designed. Intraperitoneal administration of the YSNSG cyclopeptide inhibited in vivo melanoma progression more efficiently than the native linear peptide. In the present article, we showed that the YSNSG cyclopeptide also triggered an inhibition of in vivo tumor neovascularization and we further analyzed its in vitroantiangiogenic effect. The YSNSG cyclopeptide did not alter endothelial cell proliferation but inhibited cell migration by 83% in an in vitro wound healing model. The inhibition was mediated by a decrease in active MT1-MMP at the migration front as well as a decrease in u-PA and u-PAR expression. The cyclopeptide also altered beta1-integrin distribution in endothelial cell lamellipodia, induced a strong decrease in the phosphorylated focal adhesion kinase (p125(FAK)), disorganized F-actin stress fibers and decreased the number of lamellipodia, resulting in a non migratory phenotype. Our results confirm the YSNSG cyclopeptide as a potent antitumor agent, through both the inhibition of invasive properties of tumor cells and the antiangiogenic activity. PMID:19551865

  10. 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

  11. 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.

  12. Inhibition of vacuolar ATPase subunit in tumor cells delays tumor growth by decreasing the essential macrophage population in the tumor microenvironment.

    PubMed

    Katara, G K; Kulshrestha, A; Jaiswal, M K; Pamarthy, S; Gilman-Sachs, A; Beaman, K D

    2016-02-25

    In cancer cells, vacuolar ATPase (V-ATPase), a multi-subunit enzyme, is expressed on the plasma as well as vesicular membranes and critically influences metastatic behavior. The soluble, cleaved N-terminal domain of V-ATPase a2 isoform is associated with in vitro induction of tumorigenic characteristics in macrophages. This activity led us to further investigate its in vivo role in cancer progression by inhibition of a2 isoform (a2V) in tumor cells and the concomitant effect on tumor microenvironment in the mouse 4T-1 breast cancer model. Results showed that macrophages cocultivated with a2V knockdown (sh-a2) 4T-1 cells produce lower amounts of tumorigenic factors in vitro and have reduced ability to suppress T-cell activation and proliferation compared with control 4T-1 cells. Data analysis showed a delayed mammary tumor growth in Balb/c mice inoculated with sh-a2 4T-1 cells compared with control. The purified CD11b(+) macrophages from sh-a2 tumors showed a reduced expression of mannose receptor-1 (CD206), interleukin-10, transforming growth factor-β, arginase-1, matrix metalloproteinase and vascular endothelial growth factor. Flow cytometric analysis of tumor-infiltrated macrophages showed a significantly low number of F4/80(+)CD11c(+)CD206(+) macrophages in sh-a2 tumors compared with control. In sh-a2 tumors, most of the macrophages were F4/80(+)CD11c(+) (antitumor M1 macrophages) suggesting it to be the reason behind delayed tumor growth. Additionally, tumor-infiltrating macrophages from sh-a2 tumors showed a reduced expression of CD206 compared with control whereas CD11c expression was unaffected. These findings demonstrate that in the absence of a2V in tumor cells, the resident macrophage population in the tumor microenvironment is altered which affects in vivo tumor growth. We suggest that by involving the host immune system, tumor growth can be controlled through targeting of a2V on tumor cells. PMID:25961933

  13. Arsenic trioxide disrupts glioma stem cells via promoting PML degradation to inhibit tumor growth

    PubMed Central

    Zhou, Wenchao; Cheng, Lin; Shi, Yu; Ke, Susan Q.; Huang, Zhi; Fang, Xiaoguang; Chu, Cheng-wei; Xie, Qi; Bian, Xiu-wu; Rich, Jeremy N.; Bao, Shideng

    2015-01-01

    Glioblastoma multiforme (GBM) is the most lethal brain tumor. Tumor relapse in GBM is inevitable despite maximal therapeutic interventions. Glioma stem cells (GSCs) have been found to be critical players in therapeutic resistance and tumor recurrence. Therapeutic drugs targeting GSCs may significantly improve GBM treatment. In this study, we demonstrated that arsenic trioxide (As2O3) effectively disrupted GSCs and inhibited tumor growth in the GSC-derived orthotopic xenografts by targeting the promyelocytic leukaemia (PML). As2O3 treatment induced rapid degradation of PML protein along with severe apoptosis in GSCs. Disruption of the endogenous PML recapitulated the inhibitory effects of As2O3 treatment on GSCs both in vitro and in orthotopic tumors. Importantly, As2O3 treatment dramatically reduced GSC population in the intracranial GBM xenografts and increased the survival of mice bearing the tumors. In addition, As2O3 treatment preferentially inhibited cell growth of GSCs but not matched non-stem tumor cells (NSTCs). Furthermore, As2O3 treatment or PML disruption potently diminished c-Myc protein levels through increased poly-ubiquitination and proteasome degradation of c-Myc. Our study indicated a potential implication of As2O3 in GBM treatment and highlighted the important role of PML/c-Myc axis in the maintenance of GSCs. PMID:26510911

  14. Dihydrolipoic acid inhibits tetrachlorohydroquinone-induced tumor promotion through prevention of oxidative damage.

    PubMed

    Wang, Ying-Jan; Yang, Ming-Chen; Pan, Ming-Hsiung

    2008-12-01

    alpha-Lipoic acid (LA) has been intensely investigated as a therapeutic agent for several diseases, including hepatic disorder and diabetic polyneuropathy. However, the effects of LA or its reduced form, dihydrolipoic acid (DHLA), on cancer chemoprevention has seldom been studied. Tetrachlorohydroquinone (TCHQ) is a toxic metabolite of pentachlorophenol (PCP) that was proven to be a tumor promoter in our previous study. We recently reported that DHLA can inhibit DMBA/TPA-induced skin tumor formation through its anti-inflammatory and anti-oxidizing functions. In the present study, we further examined the effects of DHLA on DMBA/TCHQ-induced skin tumor formation and the possible mechanisms. We found that DHLA significantly inhibited tumor incidence and tumor multiplicity in DMBA/TCHQ-induced skin tumor formation. Administration of DHLA prevented ROS generation, cytotoxicity, genotoxicity and apoptotic cell death in cells treated with TCHQ. In addition, activation of JNK and p38 MAPK may be involved in TCHQ-mediated apoptosis. Nonetheless, the detailed mechanisms of DHLA in attenuating TCHQ-induced skin tumor promotion are still unclear and need to be further investigated. We conclude that DHLA may be a useful protective agent against TCHQ-induced toxicity in epithelial cells, and for reversing TCHQ-induced damage in mouse skin. PMID:18951944

  15. 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.

  16. Endoglin targeting inhibits tumor angiogenesis and metastatic spread in breast cancer.

    PubMed

    Paauwe, M; Heijkants, R C; Oudt, C H; van Pelt, G W; Cui, C; Theuer, C P; Hardwick, J C H; Sier, C F M; Hawinkels, L J A C

    2016-08-01

    Endoglin, a transforming growth factor-β co-receptor, is highly expressed on angiogenic endothelial cells in solid tumors. Therefore, targeting endoglin is currently being explored in clinical trials for anti-angiogenic therapy. In this project, the redundancy between endoglin and vascular endothelial growth factor (VEGF) signaling in angiogenesis and the effects of targeting both pathways on breast cancer metastasis were explored. In patient samples, increased endoglin signaling after VEGF inhibition was observed. In vitro TRC105, an endoglin-neutralizing antibody, increased VEGF signaling in endothelial cells. Moreover, combined targeting of the endoglin and VEGF pathway, with the VEGF receptor kinase inhibitor SU5416, increased antiangiogenic effects in vitro and in a zebrafish angiogenesis model. Next, in a mouse model for invasive lobular breast cancer, the effects of TRC105 and SU5416 on tumor growth and metastasis were explored. Although TRC105 and SU5416 decreased tumor vascular density, tumor volume was unaffected. Strikingly, in mice treated with TRC105, or TRC105 and SU5416 combined, a strong inhibition in the number of metastases was seen. Moreover, upon resection of the primary tumor, strong inhibition of metastatic spread by TRC105 was observed in an adjuvant setting. To confirm these data, we assessed the effects of endoglin-Fc (an endoglin ligand trap) on metastasis formation. Similar to treatment with TRC105 in the resection model, endoglin-Fc-expressing tumors showed strong inhibition of distant metastases. These results show, for the first time, that targeting endoglin, either with neutralizing antibodies or a ligand trap, strongly inhibits metastatic spread of breast cancer in vivo. PMID:26804178

  17. 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.

  18. 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.

  19. Selective expression of constitutively active pro-apoptotic protein BikDD gene in primary mammary tumors inhibits tumor growth and reduces tumor initiating cells

    PubMed Central

    Rahal, Omar M; Nie, Lei; Chan, Li-Chuan; Li, Chia-Wei; Hsu, Yi-Hsin; Hsu, Jennifer; Yu, Dihua; Hung, Mien-Chie

    2015-01-01

    Our previous study showed that specifically delivering BikDD, a constitutive active mutant of pro-apoptotic protein Bik, to breast cancer cell xenografts in immunocompromised mice has a potent activity against tumor initiating cells (TICs), and that the combination between tyrosine kinase inhibitors (TKI) and BikDD gene therapy yielded synergistic effect on EGFR and HER2 positive breast cancer cells in immunodeficient nude mice. Those encouraging results have allowed us to propose a clinical trial using the liposome-complexing plasmid DNA expressing BikDD gene which has been approved by the NIH RAC Advisory committee. However, it is imperative to test whether systemic delivery of BikDD-expressing plasmid DNAs with liposomes into immunocompetent mice has therapeutic efficacy and tolerable side effects as what we observed in the nude mice model. In this study, we investigated the effects of BikDD gene-therapy on the primary mammary tumors, especially on tumor initiating cells (TICs), of a genetically engineered immunocompetent mouse harboring normal microenvironment and immune response. The effects on TIC population in tumors were determined by FACS analysis with different sets of murine specific TIC markers, CD49fhighCD61high and CD24+Jagged1-. First we showed in vitro that ectopic expression of BikDD in murine N202 cells derived from MMTV-HER2/Neu transgenic mouse tumors induced apoptosis and decreased the number of TICs. Consistently, systemic delivery of VISA-Claudin4-BikDD by liposome complexes significantly inhibited mammary tumor growth and slowed down residual tumor growth post cessation of therapy in MMTV-HER2/Neu transgenic mice compared to the controls. In addition, the anti-tumor effects of BikDD in vivo were consistent with decreased TIC population assessed by FACS analysis and in vitro tumorsphere formation assay of freshly isolated tumor cells. Importantly, systemic administration of BikDD did not cause significant cytotoxic response in standard

  20. Selective expression of constitutively active pro-apoptotic protein BikDD gene in primary mammary tumors inhibits tumor growth and reduces tumor initiating cells.

    PubMed

    Rahal, Omar M; Nie, Lei; Chan, Li-Chuan; Li, Chia-Wei; Hsu, Yi-Hsin; Hsu, Jennifer; Yu, Dihua; Hung, Mien-Chie

    2015-01-01

    Our previous study showed that specifically delivering BikDD, a constitutive active mutant of pro-apoptotic protein Bik, to breast cancer cell xenografts in immunocompromised mice has a potent activity against tumor initiating cells (TICs), and that the combination between tyrosine kinase inhibitors (TKI) and BikDD gene therapy yielded synergistic effect on EGFR and HER2 positive breast cancer cells in immunodeficient nude mice. Those encouraging results have allowed us to propose a clinical trial using the liposome-complexing plasmid DNA expressing BikDD gene which has been approved by the NIH RAC Advisory committee. However, it is imperative to test whether systemic delivery of BikDD-expressing plasmid DNAs with liposomes into immunocompetent mice has therapeutic efficacy and tolerable side effects as what we observed in the nude mice model. In this study, we investigated the effects of BikDD gene-therapy on the primary mammary tumors, especially on tumor initiating cells (TICs), of a genetically engineered immunocompetent mouse harboring normal microenvironment and immune response. The effects on TIC population in tumors were determined by FACS analysis with different sets of murine specific TIC markers, CD49f(high)CD61(high) and CD24(+)Jagged1(-). First we showed in vitro that ectopic expression of BikDD in murine N202 cells derived from MMTV-HER2/Neu transgenic mouse tumors induced apoptosis and decreased the number of TICs. Consistently, systemic delivery of VISA-Claudin4-BikDD by liposome complexes significantly inhibited mammary tumor growth and slowed down residual tumor growth post cessation of therapy in MMTV-HER2/Neu transgenic mice compared to the controls. In addition, the anti-tumor effects of BikDD in vivo were consistent with decreased TIC population assessed by FACS analysis and in vitro tumorsphere formation assay of freshly isolated tumor cells. Importantly, systemic administration of BikDD did not cause significant cytotoxic response in

  1. 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. PMID:19294520

  2. 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

  3. 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

  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. PMID:23894523

  5. 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

  6. 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

  7. pH-sensitive drug-delivery systems for tumor targeting.

    PubMed

    He, Xi; Li, Jianfeng; An, Sai; Jiang, Chen

    2013-12-01

    Drug-delivery system responses to stimuli have been well investigated recently. As pH decrease is observed in most solid tumors, drug-delivery systems responsive to the slightly acidic extracellular pH environment of solid tumors have been developed as a general strategy for tumor targeting. Drug vehicles that are sensitive to acidic endosome/lysosome pH have been constructed for efficient drug release in tumor cells. This review explains the mechanisms of acidic pH in the tumor microenvironment and endocytic-related organelles, endosomes and lysosomes. Nanoparticle responses to acidic extracellular pH are discussed, along with approaches for improving tumor-specific therapy. Endosome/lysosome pH-triggered vehicles are reviewed, which achieve rapid drug release in tumor cells and overcome multidrug resistance. PMID:24304248

  8. Cabozantinib inhibits growth of androgen-sensitive and castration-resistant prostate cancer and affects bone remodeling.

    PubMed

    Nguyen, Holly M; Ruppender, Nazanin; Zhang, Xiaotun; Brown, Lisha G; Gross, Ted S; Morrissey, Colm; Gulati, Roman; Vessella, Robert L; Schimmoller, Frauke; Aftab, Dana T; Corey, Eva

    2013-01-01

    Cabozantinib is an inhibitor of multiple receptor tyrosine kinases, including MET and VEGFR2. In a phase II clinical trial in advanced prostate cancer (PCa), cabozantinib treatment improved bone scans in 68% of evaluable patients. Our studies aimed to determine the expression of cabozantinib targets during PCa progression and to evaluate its efficacy in hormone-sensitive and castration-resistant PCa in preclinical models while delineating its effects on tumor and bone. Using immunohistochemistry and tissue microarrays containing normal prostate, primary PCa, and soft tissue and bone metastases, our data show that levels of MET, P-MET, and VEGFR2 are increasing during PCa progression. Our data also show that the expression of cabozantinib targets are particularly pronounced in bone metastases. To evaluate cabozantinib efficacy on PCa growth in the bone environment and in soft tissues we used androgen-sensitive LuCaP 23.1 and castration-resistant C4-2B PCa tumors. In vivo, cabozantinib inhibited the growth of PCa in bone as well as growth of subcutaneous tumors. Furthermore, cabozantinib treatment attenuated the bone response to the tumor and resulted in increased normal bone volume. In summary, the expression pattern of cabozantinib targets in primary and castration-resistant metastatic PCa, and its efficacy in two different models of PCa suggest that this agent has a strong potential for the effective treatment of PCa at different stages of the disease. PMID:24205338

  9. 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

  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. PMID:26253462

  11. Xanthatin, a novel potent inhibitor of VEGFR2 signaling, inhibits angiogenesis and tumor growth in breast cancer cells

    PubMed Central

    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. PMID:26617743

  12. Formononetin, a novel FGFR2 inhibitor, potently inhibits angiogenesis and tumor growth in preclinical models

    PubMed Central

    Wu, Zhen Feng; Chen, Che; Liu, Jia Yun; Wu, Guan Nan; Yao, Xue Quan; Liu, Fu Kun; Li, Gang; Shen, Liang

    2015-01-01

    Most anti-angiogenic therapies currently being evaluated in clinical trials target vascular endothelial growth factor (VEGF) pathway, however, the tumor vasculature can acquire resistance to VEGF-targeted therapy by shifting to other angiogenesis mechanisms. Therefore, other potential therapeutic agents that block non-VEGF angiogenic pathways need to be evaluated. Here we identified formononetin as a novel agent with potential anti-angiogenic and anti-cancer activities. Formononetin demonstrated inhibition of endothelial cell proliferation, migration, and tube formation in response to basic fibroblast growth factor 2 (FGF2). In ex vivo and in vivo angiogenesis assays, formononetin suppressed FGF2-induced microvessel sprouting of rat aortic rings and angiogenesis. To understand the underlying molecular basis, we examined the effects of formononetin on different molecular components in treated endothelial cell, and found that formononetin suppressed FGF2-triggered activation of FGFR2 and protein kinase B (Akt) signaling. Moreover, formononetin directly inhibited proliferation and blocked the oncogenic signaling pathways in breast cancer cell. In vivo, using xenograft models of breast cancer, formononetin showed growth-inhibitory activity associated with inhibition of tumor angiogenesis. Moreover, formononetin enhanced the effect of VEGFR2 inhibitor sunitinib on tumor growth inhibition. Taken together, our results indicate that formononetin targets the FGFR2-mediated Akt signaling pathway, leading to the suppression of tumor growth and angiogenesis. PMID:26575424

  13. Inhibition of PAI-1 Limits Tumor Angiogenesis Regardless of Angiogenic Stimuli in Malignant Pleural Mesothelioma.

    PubMed

    Takayama, Yusuke; Hattori, Noboru; Hamada, Hironobu; Masuda, Takeshi; Omori, Keitaro; Akita, Shin; Iwamoto, Hiroshi; Fujitaka, Kazunori; Kohno, Nobuoki

    2016-06-01

    Malignant pleural mesothelioma (MPM) is an aggressive malignant tumor that secretes various angiogenic factors. The main inhibitor of plasminogen activators, PAI-1 (SERPINE1), has been implicated in tumor progression and angiogenesis, and high PAI-1 expression has been associated with poor prognosis in MPM patients. In this study, we examined the antiangiogenic effects of PAI-1 inhibition in MPM. We administered the PAI-1 inhibitor, SK-216, to orthotopic mouse models in which MPM cells expressing high levels of VEGF (VEGFA) or bFGF (FGF2) were intrapleurally transplanted. SK-216 administration reduced tumor weights and the degree of angiogenesis in intrapleural tumors, irrespective of their angiogenic expression profiles. In addition, a combination of SK-216 and the chemotherapeutic agent cisplatin significantly reduced tumor weights compared with monotherapy, prolonging the survival of animals compared with cisplatin treatment alone. Furthermore, SK-216 inhibited migration and tube formation of cultured human umbilical vein endothelial cells induced by various angiogenic factors known to be secreted by MPM. These findings suggest that PAI-1 inactivation by SK-216 may represent a general strategy for inhibiting angiogenesis, including for the treatment of MPM. Cancer Res; 76(11); 3285-94. ©2016 AACR. PMID:27197170

  14. 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

  15. 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

    2016-01-01

    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

  16. Dietary rice component, Oryzanol, inhibits tumor growth in tumor-bearing Mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  17. Inhibition of Fatty Acid Synthase Sensitizes Prostate Cancer Cells to Radiotherapy.

    PubMed

    Rae, Colin; Haberkorn, Uwe; Babich, John W; Mairs, Robert J

    2015-11-01

    Many common human cancers, including colon, prostate and breast cancer, express high levels of fatty acid synthase compared to normal human tissues. This elevated expression is associated with protection against apoptosis, increased metastasis and poor prognosis. Inhibitors of fatty acid synthase, such as the cerulenin synthetic analog C75, decrease prostate cancer cell proliferation, increase apoptosis and decrease tumor growth in experimental models. Although radiotherapy is widely used in the treatment of prostate cancer patients, the risk of damage to neighboring normal organs limits the radiation dose that can be delivered. In this study, we examined the potential of fatty acid synthase inhibition to sensitize prostate cancer cells to radiotherapy. The efficacy of C75 alone or in combination with X irradiation was examined in monolayers and in multicellular tumor spheroids. Treatment with C75 alone decreased clonogenic survival, an effect that was abrogated by the antioxidant. C75 treatment also delayed spheroid growth in a concentration-dependent manner. The radiosensitizing effect of C75 was indicated by combination index values between 0.65 and 0.71 and the reduced surviving fraction of clonogens, in response to 2 Gy X irradiation, from 0.51 to 0.30 and 0.11 in the presence of 25 and 35 μM C75, respectively. This increased sensitivity to radiation was reduced by the presence of the antioxidant. The C75 treatment also enhanced the spheroid growth delay induced by X irradiation in a supra-additive manner. The level of radiation-induced apoptosis in prostate cancer cells was increased further by C75, which induced cell cycle arrest in the G2/M phase, but only at a concentration greater than that required for radiosensitization. Radiation-induced G2/M blockade was not affected by C75 treatment. These results suggest the potential use of fatty acid synthase inhibition to enhance the efficacy of radiotherapy of prostate carcinoma and that C75-dependent cell

  18. The Ape-1/Ref-1 redox antagonist E3330 inhibits the growth of tumor endothelium and endothelial progenitor cells: therapeutic implications in tumor angiogenesis.

    PubMed

    Zou, Gang-Ming; Karikari, Collins; Kabe, Yasuaki; Handa, Hiroshi; Anders, Robert A; Maitra, Anirban

    2009-04-01

    The apurinic/apyrimidinic endonuclease 1/redox factor-1 (Ape-1/Ref-1) is a multi-functional protein, involved in DNA repair and the activation of redox-sensitive transcription factors. The Ape-1/Ref-1 redox domain acts as a cytoprotective element in normal endothelial cells, mitigating the deleterious effects of apoptotic stimuli through induction of survival signals. We explored the role of the Ape-1/Ref-1 redox domain in the maintenance of tumor-associated endothelium, and of endothelial progenitor cells (EPCs), which contribute to tumor angiogenesis. We demonstrate that E3330, a small molecule inhibitor of the Ape-1/Ref-1 redox domain, blocks the in vitro growth of pancreatic cancer-associated endothelial cells (PCECs) and EPCs, which is recapitulated by stable expression of a dominant-negative redox domain mutant. Further, E3330 blocks the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) into CD31(+) endothelial progeny. Exposure of PCECs to E3330 results in a reduction of H-ras expression and intracellular nitric oxide (NO) levels, as well as decreased DNA-binding activity of the hypoxia-inducible transcription factor, HIF-1alpha. E3330 also reduces secreted and intracellular vascular endothelial growth factor expression by pancreatic cancer cells, while concomitantly downregulating the cognate receptor Flk-1/KDR on PCECs. Inhibition of the Ape-1/Ref-1 redox domain with E3330 or comparable angiogenesis inhibitors might be a potent therapeutic strategy in solid tumors. PMID:19097035

  19. Photoactivation of lysosomally sequestered sunitinib after angiostatic treatment causes vascular occlusion and enhances tumor growth inhibition

    PubMed Central

    Nowak-Sliwinska, P; Weiss, A; van Beijnum, J R; Wong, T J; Kilarski, W W; Szewczyk, G; Verheul, H M W; Sarna, T; van den Bergh, H; Griffioen, A W

    2015-01-01

    The angiogenesis inhibitor sunitinib is a tyrosine kinase inhibitor that acts mainly on the VEGF and PDGF pathways. We have previously shown that sunitinib is sequestered in the lysosomes of exposed tumor and endothelial cells. This phenomenon is part of the drug-induced resistance observed in the clinic. Here, we demonstrate that when exposed to light, sequestered sunitinib causes immediate destruction of the lysosomes, resulting in the release of sunitinib and cell death. We hypothesized that this photoactivation of sunitinib could be used as a vaso-occlusive vascular-targeting approach to treating cancer. Spectral properties of sunitinib and its lysosomal accumulation were measured in vitro. The human A2780 ovarian carcinoma transplanted onto the chicken chorioallantoic membrane (CAM) and the Colo-26 colorectal carcinoma model in Balb/c mice were used to test the effects of administrating sunitinib and subsequently exposing tumor tissue to light. Tumors were subsequently resected and subject to immunohistochemical analysis. In A2780 ovarian carcinoma tumors, treatment with sunitinib+light resulted in immediate specific angio-occlusion, leading to a necrotic tumor mass 24 h after treatment. Tumor growth was inhibited by 70% as compared with the control group (**P<0.0001). Similar observations were made in the Colo-26 colorectal carcinoma, where light exposure of the sunitinib-treated mice inhibited tumor growth by 50% as compared with the control and by 25% as compared with sunitinib-only-treated tumors (N≥4; P=0.0002). Histology revealed that photoactivation of sunitinib resulted in a change in tumor vessel architecture. The current results suggest that the spectral properties of sunitinib can be exploited for application against certain cancer indications. PMID:25675301

  20. Somatostatin receptor-1 induces cell cycle arrest and inhibits tumor growth in pancreatic cancer.

    PubMed

    Li, Min; Wang, Xiaochi; Li, Wei; Li, Fei; Yang, Hui; Wang, Hao; Brunicardi, F Charles; Chen, Changyi; Yao, Qizhi; Fisher, William E

    2008-11-01

    Functional somatostatin receptors (SSTR) are lost in human pancreatic cancer. Transfection of SSTR-1 inhibited pancreatic cancer cell proliferation in vitro. We hypothesize that stable transfection of SSTR-1 may inhibit pancreatic cancer growth in vivo possibly through cell cycle arrest. In this study, we examined the expression of SSTR-1 mRNA in human pancreatic cancer tissue specimens, and investigated the effect of SSTR-1 overexpression on cell proliferation, cell cycle, and tumor growth in a subcutaneous nude mouse model. We found that SSTR-1 mRNA was downregulated in the majority of pancreatic cancer tissue specimens. Transfection of SSTR-1 caused cell cycle arrest at the G(0)/G(1) growth phase, with a corresponding decline of cells in the S (mitotic) phase. The overexpression of SSTR-1 significantly inhibited subcutaneous tumor size by 71% and 43% (n = 5, P < 0.05, Student's t-test), and inhibited tumor weight by 69% and 47% (n = 5, P < 0.05, Student's t-test), in Panc-SSTR-1 and MIA-SSTR-1 groups, respectively, indicating the potent inhibitory effect of SSTR-1 on pancreatic cancer growth. Our data demonstrate that overexpression of SSTR-1 significantly inhibits pancreatic cancer growth possibly through cell cycle arrest. This study suggests that gene therapy with SSTR-1 may be a potential adjuvant treatment for pancreatic cancer. PMID:18823376

  1. Somatostatin Receptor-1 Induces Cell Cycle Arrest and Inhibits Tumor Growth in Pancreatic Cancer

    PubMed Central

    Li, Min; Wang, Xiaochi; Li, Wei; Li, Fei; Yang, Hui; Wang, Hao; Brunicardi, F. Charles; Chen, Changyi; Yao, Qizhi; Fisher, William E.

    2010-01-01

    Functional somatostatin receptors (SSTRs) are lost in human pancreatic cancer. Transfection of SSTR-1 inhibited pancreatic cancer cell proliferation in vitro. We hypothesize that stable transfection of SSTR-1 may inhibit pancreatic cancer growth in vivo possibly through cell cycle arrest. In this study, we examined the expression of SSTR-1 mRNA in human pancreatic cancer tissue specimens, and investigated the effect of SSTR-1 overexpression on cell proliferation, cell cycle, and tumor growth in in a subcutaneous nude mouse model. We found that SSTR-1 mRNA was downregulated in the majority of pancreatic cancer tissue specimens. Transfection of SSTR-1 caused cell cycle arrest at the G0/G1 growth phase, with a corresponding decline of cells in the S (mitotic) phase. The overexpression of SSTR-1 significantly inhibited subcutaneous tumor size by 71% and 43% (n=5, p<0.05, t-test), and inhibited tumor weight by 69% and 47%, (n=5, p<0.05, t-test), in Panc-SSTR-1 and MIA-SSTR-1 groups, respectively, indicating the potent inhibitory effect of SSTR-1 on pancreatic cancer growth. Our data demonstrate that overexpression of SSTR-1 significantly inhibits pancreatic cancer growth possibly through cell cycle arrest. This study suggests that gene therapy with SSTR-1 may be a potential adjuvant treatment for pancreatic cancer. PMID:18823376

  2. 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. PMID:6766937

  3. ICAM-1 suppresses tumor metastasis by inhibiting macrophage M2 polarization through blockade of efferocytosis.

    PubMed

    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

  4. Systemic miRNA-7 delivery inhibits tumor angiogenesis and growth in murine xenograft glioblastoma

    PubMed Central

    Van Beijnum, Judy R.; Cerisoli, Francesco; Scaria, Puthupparampil V.; Verheul, Mark; Van Berkel, Maaike P.; Pieters, Ebel H. E.; Van Haastert, Rick J.; Yousefi, Afrouz; Mastrobattista, Enrico; Storm, Gert; Berezikov, Eugene; Cuppen, Edwin; Woodle, Martin; Schaapveld, Roel Q. J.; Prevost, Gregoire P.; Griffioen, Arjan W.; Van Noort, Paula I.; Schiffelers, Raymond M.

    2014-01-01

    Tumor-angiogenesis is the multi-factorial process of sprouting of endothelial cells (EC) into micro-vessels to provide tumor cells with nutrients and oxygen. To explore miRNAs as therapeutic angiogenesis-inhibitors, we performed a functional screen to identify miRNAs that are able to decrease EC viability. We identified miRNA-7 (miR-7) as a potent negative regulator of angiogenesis. Introduction of miR-7 in EC resulted in strongly reduced cell viability, tube formation, sprouting and migration. Application of miR-7 in the chick chorioallantoic membrane assay led to a profound reduction of vascularization, similar to anti-angiogenic drug sunitinib. Local administration of miR-7 in an in vivo murine neuroblastoma tumor model significantly inhibited angiogenesis and tumor growth. Finally, systemic administration of miR-7 using a novel integrin-targeted biodegradable polymeric nanoparticles that targets both EC and tumor cells, strongly reduced angiogenesis and tumor proliferation in mice with human glioblastoma xenografts. Transcriptome analysis of miR-7 transfected EC in combination with in silico target prediction resulted in the identification of OGT as novel target gene of miR-7. Our study provides a comprehensive validation of miR-7 as novel anti-angiogenic therapeutic miRNA that can be systemically delivered to both EC and tumor cells and offers promise for miR-7 as novel anti-tumor therapeutic. PMID:25149532

  5. 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. PMID:26209955

  6. 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

  7. 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

  8. 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. PMID:24398427

  9. Selective inhibition of JNK with a peptide inhibitor attenuates pain hypersensitivity and tumor growth in a mouse skin cancer pain model.

    PubMed

    Gao, Yong-Jing; Cheng, Jen-Kun; Zeng, Qing; Xu, Zhen-Zhong; Decosterd, Isabelle; Xu, Xiaoyin; Ji, Ru-Rong

    2009-09-01

    Cancer pain significantly affects the quality of cancer patients, and current treatments for this pain are limited. C-Jun N-terminal kinase (JNK) has been implicated in tumor growth and neuropathic pain sensitization. We investigated the role of JNK in cancer pain and tumor growth in a skin cancer pain model. Injection of luciferase-transfected B16-Fluc melanoma cells into a hindpaw of mouse induced robust tumor growth, as indicated by increase in paw volume and fluorescence intensity. Pain hypersensitivity in this model developed rapidly (<5 days) and reached a peak in 2 weeks, and was characterized by mechanical allodynia and heat hyperalgesia. Tumor growth was associated with JNK activation in tumor mass, dorsal root ganglion (DRG), and spinal cord and a peripheral neuropathy, such as loss of nerve fibers in the hindpaw skin and induction of ATF-3 expression in DRG neurons. Repeated systemic injections of D-JNKI-1 (6 mg/kg, i.p.), a selective and cell-permeable peptide inhibitor of JNK, produced an accumulative inhibition of mechanical allodynia and heat hyperalgesia. A bolus spinal injection of D-JNKI-1 also inhibited mechanical allodynia. Further, JNK inhibition suppressed tumor growth in vivo and melanoma cell proliferation in vitro. In contrast, repeated injections of morphine (5 mg/kg), a commonly used analgesic for terminal cancer, produced analgesic tolerance after 1 day and did not inhibit tumor growth. Our data reveal a marked peripheral neuropathy in this skin cancer model and important roles of the JNK pathway in cancer pain development and tumor growth. JNK inhibitors such as D-JNKI-1 may be used to treat cancer pain. PMID:19445931

  10. Sensitive and selective tumor imaging with novel and highly activatable fluorescence strategies

    NASA Astrophysics Data System (ADS)

    Urano, Yasuteru

    2008-02-01

    Nowadays, several tumor imaging modalities such as MRI, PET and fluorescence imaging techniques have been extensively investigated. One of the central problems associated with these conventional tumor-targeted imaging methods, however, is the fact that the signal contrast between tumor and surrounding tissues relies on the efficient targeting to the tumor and the rapid sequestration or excretion of unbound agent. Among these modalities, only fluorescence imaging technique has a significant feature, in that great signal activation could be achieved which potentially leads to the selective imaging of cancer with higher tumor-to-background ratio. In this symposium, I will present some examples of fluorescence cancer imaging based on highly activatable strategies with using precisely designed novel fluorescence probes. Recently, we developed highly sensitive fluorescence probes for β-galactosidase which is applicable for living cell system. By utilizing these probes, we could establish a novel and highly activatable strategy for sensitive and selective optical imaging of imbedded tumor in the peritoneum. We took a two step procedure in that a lectin is used to localize β-galactosidase to cancer cells as an activating enzyme, and subsequent administration of a highly-sensitive fluorescence probe for the enzyme have afforded remarkable fluorescence activation selectively in tumor mass. Since the tumor-targeted enzyme can catalyze numerous substrate turnovers, a great number of fluorescent molecules could be produced and hence the rapid and sensitive detection of tumor in vivo with high tumor-to-background ratio could be achieved. Moreover, the consequent close-up investigation using fluorescence microscopy revealed that cancer microfoci as small as 200 μm could be successfully visualized.

  11. Selective inhibition of tumor cell associated Vacuolar-ATPase 'a2' isoform overcomes cisplatin resistance in ovarian cancer cells.

    PubMed

    Kulshrestha, Arpita; Katara, Gajendra K; Ginter, Jordyn; Pamarthy, Sahithi; Ibrahim, Safaa A; Jaiswal, Mukesh K; Sandulescu, Corina; Periakaruppan, Ramayee; Dolan, James; Gilman-Sachs, Alice; Beaman, Kenneth D

    2016-06-01

    Development of resistance to platinum compounds significantly hinders successful ovarian cancer (OVCA) treatment. In tumor cells, dysregulated pH gradient across cell membranes is a key physiological mechanism of metastasis/chemo-resistance. These pH alterations are mediated by aberrant activation of key multi-subunit proton pumps, Vacuolar-ATPases (V-ATPases). In tumor cells, its 'a2' isoform (V-ATPase-V0a2) is a component of functional plasma-membrane complex and promotes tumor invasion through tumor-acidification and immuno-modulation. Its involvement in chemo-resistance has not been studied. Here, we show that V-ATPase-V0a2 is over-expressed in acquired-cisplatin resistant OVCA cells (cis-A2780/cis-TOV112D). Of all the 'a' subunit isoforms, V-ATPase-V0a2 exhibited an elevated expression on plasma membrane of cisplatin-resistant cells compared to sensitive counterparts. Immuno-histochemistry revealed V-ATPase-V0a2 expression in both low grade (highly drug-resistant) and high grade (highly recurrent) human OVCA tissues indicating its role in a centralized mechanism of tumor resistance. In cisplatin resistant cells, shRNA mediated inhibition of V-ATPase-V0a2 enhanced sensitivity towards both cisplatin and carboplatin. This improved cytotoxicity was mediated by enhanced cisplatin-DNA-adduct formation and suppressed DNA-repair pathway, leading to enhanced apoptosis. Suppression of V0a2 activity strongly reduced cytosolic pH in resistant tumor cells, which is known to enhance platinum-associated DNA-damage. As an indicator of reduced metastasis and chemo-resistance, in contrast to plasma membrane localization, a diffused cytoplasmic localization of acidic vacuoles was observed in V0a2-knockdown resistant cells. Interestingly, pre-treatment with monoclonal V0a2-inhibitory antibody enhanced cisplatin cytotoxicity in resistant cells. Taken together, our findings suggest that the isoform specific inhibition of V-ATPase-V0a2 could serve as a therapeutic strategy for chemo

  12. Smart Superstructures with Ultrahigh pH-Sensitivity for Targeting Acidic Tumor Microenvironment: Instantaneous Size Switching and Improved Tumor Penetration.

    PubMed

    Li, Hong-Jun; Du, Jin-Zhi; Liu, Jing; Du, Xiao-Jiao; Shen, Song; Zhu, Yan-Hua; Wang, Xiaoyan; Ye, Xiaodong; Nie, Shuming; Wang, Jun

    2016-07-26

    The currently low delivery efficiency and limited tumor penetration of nanoparticles remain two major challenges of cancer nanomedicine. Here, we report a class of pH-responsive nanoparticle superstructures with ultrasensitive size switching in the acidic tumor microenvironment for improved tumor penetration and effective in vivo drug delivery. The superstructures were constructed from amphiphilic polymer directed assembly of platinum-prodrug conjugated polyamidoamine (PAMAM) dendrimers, in which the amphiphilic polymer contains ionizable tertiary amine groups for rapid pH-responsiveness. These superstructures had an initial size of ∼80 nm at neutral pH (e.g., in blood circulation), but once deposited in the slightly acidic tumor microenvironment (pH ∼6.5-7.0), they underwent a dramatic and sharp size transition within a very narrow range of acidity (less than 0.1-0.2 pH units) and dissociated instantaneously into the dendrimer building blocks (less than 10 nm in diameter). This rapid size-switching feature not only can facilitate nanoparticle extravasation and accumulation via the enhanced permeability and retention effect but also allows faster nanoparticle diffusion and more efficient tumor penetration. We have further carried out comparative studies of pH-sensitive and insensitive nanostructures with similar size, surface charge, and chemical composition in both multicellular spheroids and poorly permeable BxPC-3 pancreatic tumor models, whose results demonstrate that the pH-triggered size switching is a viable strategy for improving drug penetration and therapeutic efficacy. PMID:27244096

  13. 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. PMID:23832051

  14. NOS Inhibition Modulates Immune Polarization and Improves Radiation-Induced Tumor Growth Delay.

    PubMed

    Ridnour, Lisa A; Cheng, Robert Y S; Weiss, Jonathan M; Kaur, Sukhbir; Soto-Pantoja, David R; Basudhar, Debashree; Heinecke, Julie L; Stewart, C Andrew; DeGraff, William; Sowers, Anastasia L; Thetford, Angela; Kesarwala, Aparna H; Roberts, David D; Young, Howard A; Mitchell, James B; Trinchieri, Giorgio; Wiltrout, Robert H; Wink, David A

    2015-07-15

    Nitric oxide synthases (NOS) are important mediators of progrowth signaling in tumor cells, as they regulate angiogenesis, immune response, and immune-mediated wound healing. Ionizing radiation (IR) is also an immune modulator and inducer of wound response. We hypothesized that radiation therapeutic efficacy could be improved by targeting NOS following tumor irradiation. Herein, we show enhanced radiation-induced (10 Gy) tumor growth delay in a syngeneic model (C3H) but not immunosuppressed (Nu/Nu) squamous cell carcinoma tumor-bearing mice treated post-IR with the constitutive NOS inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME). These results suggest a requirement of T cells for improved radiation tumor response. In support of this observation, tumor irradiation induced a rapid increase in the immunosuppressive Th2 cytokine IL10, which was abated by post-IR administration of L-NAME. In vivo suppression of IL10 using an antisense IL10 morpholino also extended the tumor growth delay induced by radiation in a manner similar to L-NAME. Further examination of this mechanism in cultured Jurkat T cells revealed L-NAME suppression of IR-induced IL10 expression, which reaccumulated in the presence of exogenous NO donor. In addition to L-NAME, the guanylyl cyclase inhibitors ODQ and thrombospondin-1 also abated IR-induced IL10 expression in Jurkat T cells and ANA-1 macrophages, which further suggests that the immunosuppressive effects involve eNOS. Moreover, cytotoxic Th1 cytokines, including IL2, IL12p40, and IFNγ, as well as activated CD8(+) T cells were elevated in tumors receiving post-IR L-NAME. Together, these results suggest that post-IR NOS inhibition improves radiation tumor response via Th1 immune polarization within the tumor microenvironment. PMID:25990221

  15. High ALDH Activity Identifies Chemotherapy-Resistant Ewing's Sarcoma Stem Cells That Retain Sensitivity to EWS-FLI1 Inhibition

    PubMed Central

    Gul, Naheed; Katuri, Varalakshmi; O'Neill, Alison; Kong, Yali; Brown, Milton L.; Toretsky, Jeffrey A.; Loeb, David M.

    2010-01-01

    Background Cancer stem cells are a chemotherapy-resistant population capable of self-renewal and of regenerating the bulk tumor, thereby causing relapse and patient death. Ewing's sarcoma, the second most common form of bone tumor in adolescents and young adults, follows a clinical pattern consistent with the Cancer Stem Cell model – remission is easily achieved, even for patients with metastatic disease, but relapse remains frequent and is usually fatal. Methodology/Principal Findings We have isolated a subpopulation of Ewing's sarcoma cells, from both human cell lines and human xenografts grown in immune deficient mice, which express high aldehyde dehydrogenase (ALDHhigh) activity and are enriched for clonogenicity, sphere-formation, and tumor initiation. The ALDHhigh cells are resistant to chemotherapy in vitro, but this can be overcome by the ATP binding cassette transport protein inhibitor, verapamil. Importantly, these cells are not resistant to YK-4-279, a small molecule inhibitor of EWS-FLI1 that is selectively toxic to Ewing's sarcoma cells both in vitro and in vivo. Conclusions/Significance Ewing's sarcoma contains an ALDHhigh stem-like population of chemotherapy-resistant cells that retain sensitivity to EWS-FLI1 inhibition. Inhibiting the EWS-FLI1 oncoprotein may prove to be an effective means of improving patient outcomes by targeting Ewing's sarcoma stem cells that survive standard chemotherapy. PMID:21085683

  16. 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.

  17. Impaired angiogenesis and tumor development by inhibition of the mitotic kinesin Eg5

    PubMed Central

    Exertier, Prisca; Javerzat, Sophie; Wang, Baigang; Franco, Mélanie; Herbert, John; Platonova, Natalia; Winandy, Marie; Pujol, Nadège; Nivelles, Olivier; Ormenese, Sandra; Godard, Virginie; Becker, Jürgen; Bicknell, Roy; Pineau, Raphael; Wilting, Jörg; Bikfalvi, Andreas; Hagedorn, Martin

    2013-01-01

    Kinesin motor proteins exert essential cellular functions in all eukaryotes. They control mitosis, migration and intracellular transport through interaction with microtubules. Small molecule inhibitors of the mitotic kinesin KiF11/Eg5 are a promising new class of anti-neoplastic agents currently evaluated in clinical cancer trials for solid tumors and hematological malignancies. Here we report induction of Eg5 and four other mitotic kinesins including KIF20A/Mklp2 upon stimulation of in vivo angiogenesis with vascular endothelial growth factor-A (VEGF-A). Expression analyses indicate up-regulation of several kinesin-encoding genes predominantly in lymphoblasts and endothelial cells. Chemical blockade of Eg5 inhibits endothelial cell proliferation and migration in vitro. Mitosis-independent vascular outgrowth in aortic ring cultures is strongly impaired after Eg5 or Mklp2 protein inhibition. In vivo, interfering with KIF11/Eg5 function causes developmental and vascular defects in zebrafish and chick embryos and potent inhibition of tumor angiogenesis in experimental tumor models. Besides blocking tumor cell proliferation, impairing endothelial function is a novel mechanism of action of kinesin inhibitors. PMID:24327603

  18. In vivo tumor growth inhibition and biodistribution studies of locked nucleic acid (LNA) antisense oligonucleotides

    PubMed Central

    Fluiter, Kees; ten Asbroek, Anneloor L. M. A.; de Wissel, Marit B.; Jakobs, Marja E.; Wissenbach, Margit; Olsson, Håkan; Olsen, Otto; Oerum, Henrik; Baas, Frank

    2003-01-01

    Locked nucleic acids (LNA) are novel high-affinity DNA analogs that can be used as genotype-specific drugs. The LNA oligonucleotides (LNA PO ODNs) are very stable in vitro and in vivo without the need for a phosphorothiolated backbone. In this study we tested the biological fate and the efficacy in tumor growth inhibition of antisense oligonucleotides directed against the gene of the large subunit of RNA polymerase II (POLR2A) that are completely synthesized as LNA containing diester backbones. These full LNA oligonucleotides strongly reduce POLR2A protein levels. Full LNA PO ODNs appeared to be very stable compounds when injected into the circulation of mice. Full LNA PO ODNs were continuously administered for 14 days to tumor-bearing nude mice. Tumor growth was inhibited sequence specifically at dosages from 1 mg/kg/day. LNA PO ODNs appeared to be non-toxic at dosages <5 mg/kg/day. Biodistribution studies showed the kidneys to have the highest uptake of LNA PO ODNs and urinary secretion as the major route of clearance. This report shows that LNA PO ODNs are potent genotype-specific drugs that can inhibit tumor growth in vivo. PMID:12560491

  19. 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. PMID:26980763

  20. Inhibition of Ovarian Tumor Growth by Targeting the HU177 Cryptic Collagen Epitope.

    PubMed

    Caron, Jennifer M; Ames, Jacquelyn J; Contois, Liangru; Liebes, Leonard; Friesel, Robert; Muggia, Franco; Vary, Calvin P H; Oxburgh, Leif; Brooks, Peter C

    2016-06-01

    Evidence suggests that stromal cells play critical roles in tumor growth. Uncovering new mechanisms that control stromal cell behavior and their accumulation within tumors may lead to development of more effective treatments. We provide evidence that the HU177 cryptic collagen epitope is selectively generated within human ovarian carcinomas and this collagen epitope plays a role in SKOV-3 ovarian tumor growth in vivo. The ability of the HU177 epitope to regulate SKOV-3 tumor growth depends in part on its ability to modulate stromal cell behavior because targeting this epitope inhibited angiogenesis and, surprisingly, the accumulation of α-smooth muscle actin-expressing stromal cells. Integrin α10β1 can serve as a receptor for the HU177 epitope in α-smooth muscle actin-expressing stromal cells and subsequently regulates Erk-dependent migration. These findings are consistent with a mechanism by which the generation of the HU177 collagen epitope provides a previously unrecognized α10β1 ligand that selectively governs angiogenesis and the accumulation of stromal cells, which in turn secrete protumorigenic factors that contribute to ovarian tumor growth. Our findings provide a new mechanistic understanding into the roles by which the HU177 epitope regulates ovarian tumor growth and provide new insight into the clinical results from a phase 1 human clinical study of the monoclonal antibody D93/TRC093 in patients with advanced malignant tumors. PMID:27216148

  1. 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. PMID:22687625

  2. A nanoparticle system specifically designed to deliver short interfering RNA inhibits tumor growth in vivo.

    PubMed

    Yagi, Nobuhiro; Manabe, Ichiro; Tottori, Tsuneaki; Ishihara, Atsushi; Ogata, Fusa; Kim, Jong Heon; Nishimura, Satoshi; Fujiu, Katsuhito; Oishi, Yumiko; Itaka, Keiji; Kato, Yasuki; Yamauchi, Masahiro; Nagai, Ryozo

    2009-08-15

    Use of short interfering RNA (siRNA) is a promising new approach thought to have a strong potential to lead to rapid development of gene-oriented therapies. Here, we describe a newly developed, systemically injectable siRNA vehicle, the "wrapsome" (WS), which contains siRNA and a cationic lipofection complex in a core that is fully enveloped by a neutral lipid bilayer and hydrophilic polymers. WS protected siRNA from enzymatic digestion, providing a long half-life in the systemic circulation. Moreover, siRNA/WS leaked from blood vessels within tumors into the tumor tissue, where it accumulated and was subsequently transfected into the tumor cells. Because the transcription factor KLF5 is known to play a role in tumor angiogenesis, we designed KLF5-siRNA to test the antitumor activity of siRNA/WS. KLF5-siRNA/WS exhibited significant antitumor activity, although neither WS containing control scrambled-siRNA nor saline containing KLF5-siRNA affected tumor growth. KLF5-siRNA/WS inhibited Klf5 expression within tumors at both mRNA and protein levels, significantly reducing angiogenesis, and we detected no significant acute or long-term toxicity. Our findings support the idea that siRNA/WS can be used to knock down specific genes within tumors and thereby exert therapeutic effects against cancers. PMID:19654315

  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. PMID

  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. Selective disruption of rb-raf-1 kinase interaction inhibits pancreatic adenocarcinoma growth irrespective of gemcitabine sensitivity.

    PubMed

    Treviño, José G; Verma, Monika; Singh, Sandeep; Pillai, Smitha; Zhang, Dongyu; Pernazza, Daniele; Sebti, Said M; Lawrence, Nicholas J; Centeno, Barbara A; Chellappan, Srikumar P

    2013-12-01

    Inactivation of the retinoblastoma (Rb) tumor suppressor protein is widespread in human cancers. Inactivation of Rb is thought to be initiated by association with Raf-1 (C-Raf) kinase, and here we determined how RRD-251, a disruptor of the Rb-Raf-1 interaction, affects pancreatic tumor progression. Assessment of phospho-Rb levels in resected human pancreatic tumor specimens by immunohistochemistry (n = 95) showed that increased Rb phosphorylation correlated with increasing grade of resected human pancreatic adenocarcinomas (P = 0.0272), which correlated with reduced overall patient survival (P = 0.0186). To define the antitumor effects of RRD-251 (50 μmol/L), cell-cycle analyses, senescence, cell viability, cell migration, anchorage-independent growth, angiogenic tubule formation and invasion assays were conducted on gemcitabine-sensitive and -resistant pancreatic cancer cells. RRD-251 prevented S-phase entry, induced senescence and apoptosis, and inhibited anchorage-independent growth and invasion (P < 0.01). Drug efficacy on subcutaneous and orthotopic xenograft models was tested by intraperitoneal injections of RRD-251 (50 mg/kg) alone or in combination with gemcitabine (250 mg/kg). RRD-251 significantly reduced tumor growth in vivo accompanied by reduced Rb phosphorylation and lymph node and liver metastasis (P < 0.01). Combination of RRD-251 with gemcitabine showed cooperative effect on tumor growth (P < 0.01). In conclusion, disruption of the Rb-Raf-1 interaction significantly reduces the malignant properties of pancreatic cancer cells irrespective of their gemcitabine sensitivity. Selective targeting of Rb-Raf-1 interaction might be a promising strategy targeting pancreatic cancer. PMID:24107447

  6. BRAF inhibition generates a host/tumor niche that mediates therapeutic escape

    PubMed Central

    Fedorenko, Inna V.; Wargo, Jennifer A.; Flaherty, Keith T.; Messina, Jane L.; Smalley, Keiran S.M.

    2015-01-01

    The current study defines a fibroblast-derived niche that facilitates the therapeutic escape of melanoma cells from BRAF inhibition. Vemurafenib treatment led to the release of TGF-β from the melanoma cells that increased the differentiation state of the fibroblasts; an affect associated with fibronectin deposition, increase in α-smooth muscle actin (α–SMA) expression and the release of neuregulin (NRG). At the same time, vemurafenib directly activated the fibroblasts through paradoxical stimulation of the MAPK pathway, causing them to secrete hepatocyte growth factor (HGF). Treatment with the BRAF/MEK inhibitor combination reversed the release of HGF. Adhesion of melanoma cells to fibronectin was critical in amplifying the fibroblast-derived NRG and HGF-mediated PI3K/AKT survival signaling in the melanoma cells following BRAF inhibition. In co-culture studies, combination treatment with inhibitors of BRAF/MET/HER kinase was ineffective at reversing the fibroblast-mediated therapeutic escape from BRAF inhibition. Instead, it was noted that combined BRAF/PI3K inhibition overcame fibroblast-mediated drug resistance in vitro and was associated with enhanced anti-tumor effects in an in vivo xenograft model. Thus, we show melanoma cells and fibroblasts remodel their microenvironment in response to BRAF inhibition and that these adaptations allow tumor cells to evade therapy through increased PI3K/AKT survival signaling. PMID:26302068

  7. Anticancer activity of MPT0G157, a derivative of indolylbenzenesulfonamide, inhibits tumor growth and angiogenesis.

    PubMed

    Huang, Yen-Chia; Huang, Fang-I; Mehndiratta, Samir; Lai, Ssu-Chia; Liou, Jing-Ping; Yang, Chia-Ron

    2015-07-30

    Histone deacetylases (HDACs) display multifaceted functions by coordinating the interaction of signal pathways with chromatin structure remodeling and the activation of non-histone proteins; these epigenetic regulations play an important role during malignancy progression. HDAC inhibition shows promise as a new strategy for cancer therapy; three HDAC inhibitors have been approved. We previously reported that N-hydroxy-3-{4-[2-(2-methyl-1H-indol-3-yl)-ethylsulfamoyl]-phenyl}-acrylamide (MPT0G157), a novel indole-3-ethylsulfamoylphenylacrylamide compound, demonstrated potent HDAC inhibition and anti-inflammatory effects. In this study, we evaluated its anti-cancer activity in vitro and in vivo. MPT0G157 treatment significantly inhibited different tumor growth at submicromolar concentration and was particularly potent in human colorectal cancer (HCT116) cells. Apoptosis and inhibited HDACs activity induced by MPT0G157 was more potent than that by the marketed drugs PXD101 (Belinostat) and SAHA (Vorinostat). In an in vivo model, MPT0G157 markedly inhibited HCT116 xenograft tumor volume and reduced matrigel-induced angiogenesis. The anti-angiogenetic effect of MPT0G157 was found to increase the hyperacetylation of heat shock protein 90 (Hsp90) and promote hypoxia-inducible factor-1α (HIF-1α) degradation followed by down-regulation of vascular endothelial growth factor (VEGF) expression. Our results demonstrate that MPT0G157 has potential as a new drug candidate for cancer therapy. PMID:26087180

  8. Anticancer activity of MPT0G157, a derivative of indolylbenzenesulfonamide, inhibits tumor growth and angiogenesis

    PubMed Central

    Mehndiratta, Samir; Lai, Ssu-Chia; Liou, Jing-Ping; Yang, Chia-Ron

    2015-01-01

    Histone deacetylases (HDACs) display multifaceted functions by coordinating the interaction of signal pathways with chromatin structure remodeling and the activation of non-histone proteins; these epigenetic regulations play an important role during malignancy progression. HDAC inhibition shows promise as a new strategy for cancer therapy; three HDAC inhibitors have been approved. We previously reported that N-hydroxy-3-{4-[2-(2-methyl-1H-indol-3-yl)-ethylsulfamoyl]-phenyl}-acrylamide (MPT0G157), a novel indole-3-ethylsulfamoylphenylacrylamide compound, demonstrated potent HDAC inhibition and anti-inflammatory effects. In this study, we evaluated its anti-cancer activity in vitro and in vivo. MPT0G157 treatment significantly inhibited different tumor growth at submicromolar concentration and was particularly potent in human colorectal cancer (HCT116) cells. Apoptosis and inhibited HDACs activity induced by MPT0G157 was more potent than that by the marketed drugs PXD101 (Belinostat) and SAHA (Vorinostat). In an in vivo model, MPT0G157 markedly inhibited HCT116 xenograft tumor volume and reduced matrigel-induced angiogenesis. The anti-angiogenetic effect of MPT0G157 was found to increase the hyperacetylation of heat shock protein 90 (Hsp90) and promote hypoxia-inducible factor-1α (HIF-1α) degradation followed by down-regulation of vascular endothelial growth factor (VEGF) expression. Our results demonstrate that MPT0G157 has potential as a new drug candidate for cancer therapy. PMID:26087180

  9. Combined Inhibition of DNMT and HDAC Blocks the Tumorigenicity of Cancer Stem-like Cells and Attenuates Mammary Tumor Growth.

    PubMed

    Pathania, Rajneesh; Ramachandran, Sabarish; Mariappan, Gurusamy; Thakur, Priyanka; Shi, Huidong; Choi, Jeong-Hyeon; Manicassamy, Santhakumar; Kolhe, Ravindra; Prasad, Puttur D; Sharma, Suash; Lokeshwar, Bal L; Ganapathy, Vadivel; Thangaraju, Muthusamy

    2016-06-01

    Recently, impressive technical advancements have been made in the isolation and validation of mammary stem cells and cancer stem cells (CSC), but the signaling pathways that regulate stem cell self-renewal are largely unknown. Furthermore, CSCs are believed to contribute to chemo- and radioresistance. In this study, we used the MMTV-Neu-Tg mouse mammary tumor model to identify potential new strategies for eliminating CSCs. We found that both luminal progenitor and basal stem cells are susceptible to genetic and epigenetic modifications, which facilitate oncogenic transformation and tumorigenic potential. A combination of the DNMT inhibitor 5-azacytidine and the HDAC inhibitor butyrate markedly reduced CSC abundance and increased the overall survival in this mouse model. RNA-seq analysis of CSCs treated with 5-azacytidine plus butyrate provided evidence that inhibition of chromatin modifiers blocks growth-promoting signaling molecules such as RAD51AP1 and SPC25, which play key roles in DNA damage repair and kinetochore assembly. Moreover, RAD51AP1 and SPC25 were significantly overexpressed in human breast tumor tissues and were associated with reduced overall patient survival. In conclusion, our studies suggest that breast CSCs are intrinsically sensitive to genetic and epigenetic modifications and can therefore be significantly affected by epigenetic-based therapies, warranting further investigation of combined DNMT and HDAC inhibition in refractory or drug-resistant breast cancer. Cancer Res; 76(11); 3224-35. ©2016 AACR. PMID:27197203

  10. Neutralizing S1P inhibits intratumoral hypoxia, induces vascular remodelling and sensitizes to chemotherapy in prostate cancer

    PubMed Central

    Ader, Isabelle; Golzio, Muriel; Andrieu, Guillaume; Zalvidea, Santiago; Richard, Sylvain; Sabbadini, Roger A.; Malavaud, Bernard; Cuvillier, Olivier

    2015-01-01

    Hypoxia promotes neovascularization, increased tumor growth, and therapeutic resistance. The transcription factor, hypoxia-inducible factor 1α (HIF-1α), has been reported as the master driver of adaptation to hypoxia. We previously identified the sphingosine kinase 1/sphingosine 1-phosphate (SphK1/S1P) pathway as a new modulator of HIF-1α under hypoxia. Taking advantage of a monoclonal antibody neutralizing extracellular S1P (sphingomab), we report that inhibition of S1P extracellular signaling blocks HIF-1α accumulation and activity in several cancer cell models exposed to hypoxia. In an orthotopic xenograft model of prostate cancer, we show that sphingomab reduces hypoxia and modifies vessel architecture within 5 days of treatment, leading to increased intratumoral blood perfusion. Supporting the notion that a transient vascular normalization of tumor vessels is the mechanism by which sphingomab exerts its effects, we demonstrate that administration of the antibody for 5 days before chemotherapy is more effective at local tumor control and metastatic dissemination than any other treatment scheduling. These findings validate sphingomab as a potential new normalization agent that could contribute to successful sensitization of hypoxic tumors to chemotherapy. PMID:25915662

  11. Neutralizing S1P inhibits intratumoral hypoxia, induces vascular remodelling and sensitizes to chemotherapy in prostate cancer.

    PubMed

    Ader, Isabelle; Gstalder, Cécile; Bouquerel, Pierre; Golzio, Muriel; Andrieu, Guillaume; Zalvidea, Santiago; Richard, Sylvain; Sabbadini, Roger A; Malavaud, Bernard; Cuvillier, Olivier

    2015-05-30

    Hypoxia promotes neovascularization, increased tumor growth, and therapeutic resistance. The transcription factor, hypoxia-inducible factor 1α (HIF-1α), has been reported as the master driver of adaptation to hypoxia. We previously identified the sphingosine kinase 1/sphingosine 1-phosphate (SphK1/S1P) pathway as a new modulator of HIF-1α under hypoxia. Taking advantage of a monoclonal antibody neutralizing extracellular S1P (sphingomab), we report that inhibition of S1P extracellular signaling blocks HIF-1α accumulation and activity in several cancer cell models exposed to hypoxia. In an orthotopic xenograft model of prostate cancer, we show that sphingomab reduces hypoxia and modifies vessel architecture within 5 days of treatment, leading to increased intratumoral blood perfusion. Supporting the notion that a transient vascular normalization of tumor vessels is the mechanism by which sphingomab exerts its effects, we demonstrate that administration of the antibody for 5 days before chemotherapy is more effective at local tumor control and metastatic dissemination than any other treatment scheduling. These findings validate sphingomab as a potential new normalization agent that could contribute to successful sensitization of hypoxic tumors to chemotherapy. PMID:25915662

  12. Adeno-associated virus sensitizes HeLa cell tumors to gamma rays.

    PubMed Central

    Walz, C; Schlehofer, J R; Flentje, M; Rudat, V; zur Hausen, H

    1992-01-01

    Infection with the helper virus-dependent human parvovirus adeno-associated virus (AAV) is known to interfere with cellular transformation in vitro and oncogenesis in vivo. Here we report on sensitization to gamma irradiation by AAV infection of cells in culture and of tumors established from HeLa cells grafted into immunodeficient (nude) mice: infection of HeLa cells with AAV type 2 enhanced cell killing and reduced plating efficiency after irradiation compared with uninfected cells. Similarly, HeLa cell tumors in nude mice displayed a reduced growth rate and were more sensitive to gamma irradiation when the animals were infected with AAV type 2 prior to or after tumor cell inoculation. Since no pathogenicity is known for AAV, the ability of this virus to render radiotherapy of human tumor cells more efficient may up open novel approaches in cancer treatment. Images PMID:1323717

  13. 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

  14. Emodin Inhibits Breast Cancer Growth by Blocking the Tumor-Promoting Feedforward Loop between Cancer Cells and Macrophages.

    PubMed

    Iwanowycz, Stephen; Wang, Junfeng; Hodge, Johnie; Wang, Yuzhen; Yu, Fang; Fan, Daping

    2016-08-01

    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 antitumor 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 MCP1 and CSF1, as well as expression of surface anchoring molecule Thy-1, thus suppressing macrophage migration toward 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. Mol Cancer Ther; 15(8); 1931-42. ©2016 AACR. PMID:27196773

  15. 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

  16. Dual HER/VEGF receptor targeting inhibits in vivo ovarian cancer tumor growth.

    PubMed

    Becker, Marc A; Farzan, Thahir; Harrington, Sean C; Krempski, James W; Weroha, S John; Hou, Xiaonan; Kalli, Kimberly R; Wong, Tai W; Haluska, Paul

    2013-12-01

    Ovarian cancer mortality ranks highest among all gynecologic cancers with growth factor pathways playing an integral role in tumorigenesis, metastatic dissemination, and therapeutic resistance. The HER and VEGF receptor (VEGFR) are both overexpressed and/or aberrantly activated in subsets of ovarian tumors. While agents targeting either the HER or VEGF pathways alone have been investigated, the impact of these agents have not led to overall survival benefit in ovarian cancer. We tested the hypothesis that cotargeting HER and VEGFR would maximize antitumor efficacy at tolerable doses. To this end, ovarian cancer xenografts grown intraperitoneally in athymic nude mice were tested in response to AC480 (pan-HER inhibitor, "HERi"), cediranib (pan-VEGFR inhibitor "VEGFRi"), or BMS-690514 (combined HER/VEGFR inhibitor "EVRi"). EVRi was superior to both HERi and VEGFRi in terms of tumor growth, final tumor weight, and progression-free survival. Correlative tumor studies employing phosphoproteomic antibody arrays revealed distinct agent-specific alterations, with EVRi inducing the greatest overall effect on growth factor signaling. These data suggest that simultaneous inhibition of HER and VEGFR may benefit select subsets of ovarian cancer tumors. To this end, we derived a novel HER/VEGF signature that correlated with poor overall survival in high-grade, late stage, serous ovarian cancer patient tumors. PMID:24130056

  17. Targeting a novel domain in podoplanin for inhibiting platelet-mediated tumor metastasis

    PubMed Central

    Sekiguchi, Takaya; Takemoto, Ai; Takagi, Satoshi; Takatori, Kazuki; Sato, Shigeo; Takami, Miho; Fujita, Naoya

    2016-01-01

    Podoplanin/Aggrus is a sialoglycoprotein expressed in various cancers. We previously identified podoplanin as a key factor in tumor-induced platelet aggregation. Podoplanin-mediated platelet aggregation enhances tumor growth and metastasis by secreting growth factors and by forming tumor emboli in the microvasculature. Thus, precise analysis of the mechanisms of podoplanin-mediated platelet aggregation is critical for developing anti-tumor therapies. Here we report the discovery of a novel platelet aggregation-inducing domain, PLAG4 (81-EDLPT-85). PLAG4 has high homology to the previously reported PLAG3 and contributes to the binding of its platelet receptor CLEC-2. Mutant analyses indicated that PLAG4 exhibits a predominant platelet-aggregating function relative to PLAG3 and that conserved Glu81/Asp82/Thr85 residues in PLAG4 are indispensable for CLEC-2 binding. By establishing anti-PLAG4-neutralizing monoclonal antibodies, we confirmed its role in CLEC-2 binding, platelet aggregation, and tumor emboli formation. Our results suggest the requirement of simultaneous inhibition of PLAG3/4 for complete suppression of podoplanin-mediated tumor growth and metastasis. PMID:26684030

  18. Inhibition of DNA Methylation Suppresses Intestinal Tumor Organoids by Inducing an Anti-Viral Response

    PubMed Central

    Saito, Yoshimasa; Nakaoka, Toshiaki; Sakai, Kasumi; Muramatsu, Toshihide; Toshimitsu, Kohta; Kimura, Masaki; Kanai, Takanori; Sato, Toshiro; Saito, Hidetsugu

    2016-01-01

    Recent studies have proposed that the major anti-tumor effect of DNA methylation inhibitors is induction of interferon-responsive genes via dsRNAs-containing endogenous retroviruses. Recently, a 3D culture system for stem cells known as organoid culture has been developed. Lgr5-positive stem cells form organoids that closely recapitulate the properties of original tissues. To investigate the effect of DNA demethylation on tumor organoids, we have established organoids from intestinal tumors of ApcMin/+ (Min) mice and subjected them to 5-aza-2′-deoxycytidine (5-Aza-CdR) treatment and Dnmt1 knockdown. DNA demethylation induced by 5-Aza-CdR treatment and Dnmt1 knockdown significantly reduced the cell proliferation of the tumor organoids. Microarray analyses of the tumor organoids after 5-Aza-CdR treatment and Dnmt1 knockdown revealed that interferon-responsive genes were activated by DNA demethylation. Gene ontology and pathway analyses clearly demonstrated that these genes activated by DNA demethylation are involved in the anti-viral response. These findings indicate that DNA demethylation suppresses the proliferation of intestinal tumor organoids by inducing an anti-viral response including activation of interferon-responsive genes. Treatment with DNA methylation inhibitors to activate a growth-inhibiting immune response may be an effective therapeutic approach for colon cancers. PMID:27143627

  19. CXCR3 as a molecular target in breast cancer metastasis: inhibition of tumor cell migration and promotion of host anti-tumor immunity

    PubMed Central

    Zhu, Guiquan; Jian, Jiang; Achyut, Bhagelu R.; Liang, Xinhua; Weiss, Jonathan M.; Wiltrout, Robert H.; Hollander, M. Christine; Yang, Li

    2015-01-01

    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. PMID:26485767

  20. 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

  1. Targeting ATR in vivo using the novel inhibitor VE-822 results in selective sensitization of pancreatic tumors to radiation

    PubMed Central

    Fokas, E; Prevo, R; Pollard, J R; Reaper, P M; Charlton, P A; Cornelissen, B; Vallis, K A; Hammond, E M; Olcina, M M; Gillies McKenna, W; Muschel, R J; Brunner, T B

    2012-01-01

    Combined radiochemotherapy is the currently used therapy for locally advanced pancreatic ductal adenocarcinoma (PDAC), but normal tissue toxicity limits its application. Here we test the hypothesis that inhibition of ATR (ATM-Rad3-related) could increase the sensitivity of the cancer cells to radiation or chemotherapy without affecting normal cells. We tested VE-822, an ATR inhibitor, for in vitro and in vivo radiosensitization. Chk1 phosphorylation was used to indicate ATR activity, γH2AX and 53BP1 foci as evidence of DNA damage and Rad51 foci for homologous recombination activity. Sensitivity to radiation (XRT) and gemcitabine was measured with clonogenic assays in vitro and tumor growth delay in vivo. Murine intestinal damage was evaluated after abdominal XRT. VE-822 inhibited ATR in vitro and in vivo. VE-822 decreased maintenance of cell-cycle checkpoints, increased persistent DNA damage and decreased homologous recombination in irradiated cancer cells. VE-822 decreased survival of pancreatic cancer cells but not normal cells in response to XRT or gemcitabine. VE-822 markedly prolonged growth delay of pancreatic cancer xenografts after XRT and gemcitabine-based chemoradiation without augmenting normal cell or tissue toxicity. These findings support ATR inhibition as a promising new approach to improve the therapeutic ration of radiochemotherapy for patients with PDAC. PMID:23222511

  2. Targeting ATR in vivo using the novel inhibitor VE-822 results in selective sensitization of pancreatic tumors to radiation.

    PubMed

    Fokas, E; Prevo, R; Pollard, J R; Reaper, P M; Charlton, P A; Cornelissen, B; Vallis, K A; Hammond, E M; Olcina, M M; Gillies McKenna, W; Muschel, R J; Brunner, T B

    2012-01-01

    Combined radiochemotherapy is the currently used therapy for locally advanced pancreatic ductal adenocarcinoma (PDAC), but normal tissue toxicity limits its application. Here we test the hypothesis that inhibition of ATR (ATM-Rad3-related) could increase the sensitivity of the cancer cells to radiation or chemotherapy without affecting normal cells. We tested VE-822, an ATR inhibitor, for in vitro and in vivo radiosensitization. Chk1 phosphorylation was used to indicate ATR activity, γH2AX and 53BP1 foci as evidence of DNA damage and Rad51 foci for homologous recombination activity. Sensitivity to radiation (XRT) and gemcitabine was measured with clonogenic assays in vitro and tumor growth delay in vivo. Murine intestinal damage was evaluated after abdominal XRT. VE-822 inhibited ATR in vitro and in vivo. VE-822 decreased maintenance of cell-cycle checkpoints, increased persistent DNA damage and decreased homologous recombination in irradiated cancer cells. VE-822 decreased survival of pancreatic cancer cells but not normal cells in response to XRT or gemcitabine. VE-822 markedly prolonged growth delay of pancreatic cancer xenografts after XRT and gemcitabine-based chemoradiation without augmenting normal cell or tissue toxicity. These findings support ATR inhibition as a promising new approach to improve the therapeutic ration of radiochemotherapy for patients with PDAC. PMID:23222511

  3. Phosphorescence Monitoring of Hypoxic Microenvironment in Solid-Tumors to Evaluate Chemotherapeutic Effects Using the Hypoxia-Sensitive Iridium (III) Coordination Compound

    PubMed Central

    Shang, Jin; Ma, Jingwen; Wang, Rong; Deng, Lei; Guo, Youmin; Zhong, Fan; Bai, Mingfeng; Zhang, Shaojuan; Wu, Daocheng

    2015-01-01

    Objectives To utilize phosphorescence to monitor hypoxic microenvironment in solid-tumors and investigate cancer chemotherapeutic effects in vivo. Methods A hypoxia-sensitive probe named BTP was used to monitor hypoxic microenvironment in solid-tumors. The low-dose metronomic treatment with cisplatin was used in anti-angiogenetic chemotherapeutic programs. The phosphorescence properties of BTP were detected by a spectrofluorometer. BTP cytotoxicity utilized cell necrosis and apoptosis, which were evaluated by trypan blue dye exclusion and Hoechst33342 plus propidium iodide assays. Tumor-bearing mouse models of colon adenocarcinoma were used for tumor imaging in vivo. Monitoring of the hypoxic microenvironment in tumors was performed with a Maestro 2 fluorescence imaging system. Tumor tissues in each group were harvested regularly and treated with pathological hematoxylin and eosin and immunohistochemical staining to confirm imaging results. Results BTP did not feature obvious cytotoxicity for cells, and tumor growth in low-dose metronomic cisplatin treated mice was significantly inhibited by chemotherapy. Hypoxic levels significantly increased due to cisplatin, as proven by the expression level of related proteins. Phosphorescence intensity in the tumors of mice in the cisplatin group was stronger and showed higher contrast than that in tumors of saline treated mice. Conclusions We develop a useful phosphorescence method to evaluate the chemotherapeutic effects of cisplatin. The proposed method shows potential as a phosphorescence imaging approach for evaluating chemotherapeutic effects in vivo, especially anti-angiogenesis. PMID:25786221

  4. Connexin 43 Inhibition Sensitizes Chemoresistant Glioblastoma Cells to Temozolomide.

    PubMed

    Murphy, Susan F; Varghese, Robin T; Lamouille, Samy; Guo, Sujuan; Pridham, Kevin J; Kanabur, Pratik; Osimani, Alyssa M; Sharma, Shaan; Jourdan, Jane; Rodgers, Cara M; Simonds, Gary R; Gourdie, Robert G; Sheng, Zhi

    2016-01-01

    Resistance of glioblastoma (GBM) to the front-line chemotherapeutic agent temozolomide (TMZ) continues to challenge GBM treatment efforts. The repair of TMZ-induced DNA damage by O-6-methylguanine-DNA methyltransferase (MGMT) confers one mechanism of TMZ resistance. Paradoxically, MGMT-deficient GBM patients survive longer despite still developing resistance to TMZ. Recent studies indicate that the gap junction protein connexin 43 (Cx43) renders GBM cells resistant to TMZ through its carboxyl terminus (CT). In this study, we report insights into how Cx43 promotes TMZ resistance. Cx43 levels were inversely correlated with TMZ sensitivity of GBM cells, including GBM stem cells. Moreover, Cx43 levels inversely correlated with patient survival, including as observed in MGMT-deficient GBM patients. Addition of the C-terminal peptide mimetic αCT1, a selective inhibitor of Cx43 channels, sensitized human MGMT-deficient and TMZ-resistant GBM cells to TMZ treatment. Moreover, combining αCT1 with TMZ-blocked AKT/mTOR signaling, induced autophagy and apoptosis in TMZ-resistant GBM cells. Our findings suggest that Cx43 may offer a biomarker to predict the survival of patients with MGMT-independent TMZ resistance and that combining a Cx43 inhibitor with TMZ could enhance therapeutic responses in GBM, and perhaps other TMZ-resistant cancers. PMID:26542214

  5. Breast tumor cells isolated from in vitro resistance to trastuzumab remain sensitive to trastuzumab anti-tumor effects in vivo and to ADCC killing.

    PubMed

    Kute, Timothy E; Savage, Lori; Stehle, John R; Kim-Shapiro, Jung W; Blanks, Michael J; Wood, James; Vaughn, James P

    2009-11-01

    An understanding of model systems of trastuzumab (Herceptin) resistance is of great importance since the humanized monoclonal antibody is now used as first line therapy with paclitaxel in patients with metastatic Her2 overexpressing breast cancer, and the majority of their tumors has innate resistance or develops acquired resistance to the treatment. Previously, we selected trastuzumab-resistant clonal cell lines in vitro from trastuzumab-sensitive parental BT-474 cells and showed that cloned trastuzumab-resistant cell lines maintain similar levels of the extracellular Her2 receptor, bind trastuzumab as efficiently as the parental cells, but continue to grow in the presence of trastuzumab and display cell cycle profiles and growth rates comparable to parental cells grown in the absence of trastuzumab (Kute et al. in Cytometry A 57:86-93, 2004). We now show that trastuzumab-resistant and trastuzumab-sensitive cells both surprisingly display trastuzumab-mediated growth inhibition in athymic nude mice. This demonstrates that resistance developed in vitro is not predictive of resistance in vivo. The observation that in vitro resistant cells are sensitive to trastuzumab in vivo could be explained by antibody dependent cellular cytotoxicity (ADCC). Therefore, both parental and trastuzumab-resistant cells were assayed for ADCC in real time on electroplates with and without trastuzumab in the presence of a natural killer cell line (NK-92), and granulocyte or mononuclear cellular fractions isolated from human peripheral blood. Mononuclear cells and NK-92 cells were more effective in killing both parental and trastuzumab-resistant cells in the presence of trastuzumab. Both trastuzumab-resistant cells and trastuzumab-sensitive cells showed similar susceptibility to ADCC despite displaying divergent growth responses to trastuzumab. The granulocyte fraction was able to kill these cells with equal efficacy in the presence or absence of trastuzumab. These results support a model

  6. Inhibition of cystine uptake disrupts the growth of primary brain tumors.

    PubMed

    Chung, Wook Joon; Lyons, Susan A; Nelson, Gina M; Hamza, Hashir; Gladson, Candece L; Gillespie, G Yancey; Sontheimer, Harald

    2005-08-01

    Glial cells play an important role in sequestering neuronally released glutamate via Na+-dependent transporters. Surprisingly, these transporters are not operational in glial-derived tumors (gliomas). Instead, gliomas release glutamate, causing excitotoxic death of neurons in the vicinity of the tumor. We now show that glutamate release from glioma cells is an obligatory by-product of cellular cystine uptake via system xc-, an electroneutral cystine-glutamate exchanger. Cystine is an essential precursor for the biosynthesis of glutathione, a major redox regulatory molecule that protects cells from endogenously produced reactive oxygen species (ROS). Glioma cells, but not neurons or astrocytes, rely primarily on cystine uptake via system xc- for their glutathione synthesis. Inhibition of system xc- causes a rapid depletion of glutathione, and the resulting loss of ROS defense causes caspase-mediated apoptosis. Glioma cells can be rescued if glutathione status is experimentally restored or if glutathione is substituted by alternate cellular antioxidants, confirming that ROS are indeed mediators of cell death. We describe two potent drugs that permit pharmacological inhibition of system xc-. One of these drugs, sulfasalazine, is clinically used to treat inflammatory bowel disease and rheumatoid arthritis. Sulfasalazine was able to reduce glutathione levels in tumor tissue and slow tumor growth in vivo in a commonly used intracranial xenograft animal model for human gliomas when administered by intraperitoneal injection. These data suggest that inhibition of cystine uptake into glioma cells through the pharmacological inhibition of system xc- may be a viable therapeutic strategy with a Food and Drug Administration-approved drug already in hand. PMID:16079392

  7. Delphinidin Inhibits Tumor Growth by Acting on VEGF Signalling in Endothelial Cells

    PubMed Central

    Anton, Anita; Justiniano, Hélène; Soleti, Raffaella; Alabed Alibrahim, Eid; Simard, Gilles; Andriantsitohaina, Ramaroson; Lugnier, Claire

    2015-01-01

    The vasculoprotective properties of delphinidin are driven mainly by its action on endothelial cells. Moreover, delphinidin displays anti-angiogenic properties in both in vitro and in vivo angiogenesis models and thereby might prevent the development of tumors associated with excessive vascularization. This study was aimed to test the effect of delphinidin on melanoma-induced tumor growth with emphasis on its molecular mechanism on endothelial cells. Delphinidin treatment significantly decreased in vivo tumor growth induced by B16-F10 melanoma cell xenograft in mice. In vitro, delphinidin was not able to inhibit VEGFR2-mediated B16-F10 melanoma cell proliferation but it specifically reduced basal and VEGFR2-mediated endothelial cell proliferation. The anti-proliferative effect of delphinidin was reversed either by the MEK1/2 MAP kinase inhibitor, U-0126, or the PI3K inhibitor, LY-294002. VEGF-induced proliferation was reduced either by U-0126 or LY-294002. Under these conditions, delphinidin failed to decrease further endothelial cell proliferation. Delphinidin prevented VEGF-induced phosphorylation of ERK1/2 and p38 MAPK and decreased the expression of the transcription factors, CREB and ATF1. Finally, delphinidin was more potent in inhibiting in vitro cyclic nucleotide phosphodiesterases (PDEs), PDE1 and PDE2, compared to PDE3-PDE5. Altogether delphinidin reduced tumor growth of melanoma cell in vivo by acting specifically on endothelial cell proliferation. The mechanism implies an association between inhibition of VEGF-induced proliferation via VEGFR2 signalling, MAPK, PI3K and at transcription level on CREB/ATF1 factors, and the inhibition of PDE2. In conjunction with our previous studies, we demonstrate that delphinidin is a promising compound to prevent pathologies associated with generation of vascular network in tumorigenesis. PMID:26694325

  8. Müllerian inhibiting substance/anti-Müllerian hormone: A novel treatment for gynecologic tumors

    PubMed Central

    Kim, Jang Heub; MacLaughlin, David T.

    2014-01-01

    Müllerian inhibiting substance (MIS), also called anti-Müllerian hormone (AMH), is a member of the transforming growth factor-β super-family of growth and differentiation response modifiers. It is produced in immature Sertoli cells in male embryos and binds to MIS/AMH receptors in primordial Müllerian ducts to cause regression of female reproductive structures that are the precursors to the fallopian tubes, the surface epithelium of the ovaries, the uterus, the cervix, and the upper third of the vagina. Because most gynecologic tumors originate from Müllerian duct-derived tissues, and since MIS/AMH causes regression of the Müllerian duct in male embryos, it is expected to inhibit the growth of gynecologic tumors. Purified recombinant human MIS/AMH causes growth inhibition of epithelial ovarian cancer cells and cell lines in vitro and in vitro via MIS receptor-mediated mechanism. Furthermore, several lines of evidence suggest that MIS/AMH inhibits proliferation in tissues and cell lines of other MIS/AMH receptor-expressing gynecologic tumors such as cervical, endometrial, breast, and in endometriosis as well. These findings indicate that bioactive MIS/AMH recombinant protein should be tested in patients against tumors expressing the MIS/AMH receptor complex, perhaps beginning with ovarian cancer because it has the worst prognosis. The molecular tools to identify MIS/AMH receptor expressing ovarian and other cancers are in place, thus, it is possible to select patients for treatment. An MIS/AMH ELISA exists to follow administered doses of MIS/AMH, as well. Clinical trials await the production of sufficient supplies of qualified recombinant human MIS/AMH for this purpose. PMID:25264524

  9. Cabozantinib inhibits prostate cancer growth and prevents tumor-induced bone lesions

    PubMed Central

    Dai, Jinlu; Zhang, Honglai; Karatsinides, Andreas; Keller, Jill M.; Kozloff, Kenneth M.; Aftab, Dana T.; Schimmoller, Frauke; Keller, Evan T.

    2013-01-01

    Purpose Cabozantinib, an orally available multi-tyrosine kinase inhibitor with activity against MET and vascular endothelial growth factor receptor 2 (VEGFR2), induces resolution of bone scan lesions in men with castration-resistant prostate cancer bone metastases. The purpose of this study was to determine whether cabozantinib elicited a direct anti-tumor effect, an indirect effect through modulating bone, or both. Experimental Design Using human prostate cancer xenograft studies in mice we determined cabozantinib's impact on tumor growth in soft tissue and bone. In vitro studies with cabozantinib were performed using (1) prostate cancer cell lines to evaluate its impact on cell growth, invasive ability and MET and (2) osteoblast cell lines to evaluate its impact on viability and differentiation and VEGFR2. Results Cabozantinib inhibited progression of multiple prostate cancer cell lines (Ace-1,C4-2B, and LuCaP 35) in bone metastatic and soft tissue murine models of prostate cancer, except for PC-3 prostate cancer cells in which it inhibited only subcutaneous growth. Cabozantinib directly inhibited prostate cancer cell viability and induced apoptosis in vitro and in vivo and inhibited cell invasion in vitro. Cabozantinib had a dose-dependent biphasic effect on osteoblast activity and inhibitory effect on osteoclast production in vitro, that was reflected in vivo. It blocked MET and VEGFR2 phosphorylation in prostate cancer cells and osteoblast-like cells, respectively. Conclusion These data indicate that cabozantinib has direct anti-tumor activity; and that its ability to modulate osteoblast activity may contribute to its anti-tumor efficacy. PMID:24097861

  10. CDDO-Me inhibits tumor growth and prevents recurrence of pancreatic ductal adenocarcinoma

    PubMed Central

    GAO, XIAOHUA; DEEB, DORRAH; LIU, YONGBO; LIU, PATRICIA; ZHANG, YIGUAN; SHAW, JIAJIU; GAUTAM, SUBHASH C.

    2015-01-01

    Methyl-2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oate (CDDO-Me) has shown potent antitumorigenic activity against a wide range of cancer cell lines in vitro and inhibited the growth of liver, lung and prostate cancer in vivo. In the present study, we examined the antitumor activity of CDDO-Me for pancreatic ductal adenocarcinoma (PDAC) cells with and without activating K-ras mutations. Treatment of K-ras mutant MiaPaCa-2 and K-ras normal BxPC-3 cells with CDDO-Me elicited strong antiproliferative and proapop-topic responses in both cell lines in culture. The inhibition of cell proliferation and induction of apoptosis was accompanied by the inhibition of antiapoptotic/prosurvival p-Akt, NF-κB and p-mTOR signaling proteins. For testing efficacy of CDDO-Me in vivo heterotopic and orthotopic xenografts were generated by implanting BxPC-3 and MiaPaCa-2 cells subcutaneously and in the pancreatic tail, respectively. Treatment with CDDO-Me significantly inhibited the growth of BxPC-3 xenografts and reduced the levels of p-Akt and p-mTOR in tumor tissue. In mice with orthotopic MiaPaCa-2 xenografts, treatment with CDDO-Me prolonged the survival of mice when administered following the surgical resection of tumors. The latter was attributed to the eradication of residual PDAC remaining after resection of tumors. These preclinical data demonstrate the potential of CDDO-Me for treating primary PDAC tumors and for preventing relapse/recurrence through the destruction of residual disease. PMID:26497549

  11. Glipizide, an antidiabetic drug, suppresses tumor growth and metastasis by inhibiting angiogenesis.

    PubMed

    Qi, Cuiling; Zhou, Qin; Li, Bin; Yang, Yang; Cao, Liu; Ye, Yuxiang; Li, Jiangchao; Ding, Yi; Wang, Huiping; Wang, Jintao; He, Xiaodong; Zhang, Qianqian; Lan, Tian; Lee, Kenneth Ka Ho; Li, Weidong; Song, Xiaoyu; Zhou, Jia; Yang, Xuesong; Wang, Lijing

    2014-10-30

    Angiogenesis is involved in the development, progression and metastasis of various human cancers. Herein, we report the discovery of glipizide, a widely used drug for type 2 diabetes mellitus, as a promising anticancer agent through the inhibition of tumor angiogenesis. By high-throughput screening (HTS) of an FDA approved drug library utilizing our in vivo chick embryo chorioallantoic membrane (CAM) and yolk sac membrane (YSM) models, glipizide has been identified to significantly inhibit blood vessel formation and development. Moreover, glipizide was found to suppress tumor angiogenesis, tumor growth and metastasis using xenograft tumor and MMTV-PyMT transgenic mouse models. We further revealed that the anticancer capability of glipizide is not attributed to its antiproliferative effects, which are not significant against various human cancer cell lines. To investigate whether its anticancer efficacy is associated with the glucose level alteration induced by glipizide application, glimepiride, another medium to long-acting sulfonylurea antidiabetic drug in the same class, was employed for the comparison studies in the same fashion. Interestingly, glimepiride has demonstrated no significant impact on the tumor growth and metastasis, indicating that the anticancer effects of glipizide is not ascribed to its antidiabetic properties. Furthermore, glipizide suppresses endothelial cell migration and the formation of tubular structures, thereby inhibiting angiogenesis by up-regulating the expression of natriuretic peptide receptor A. These findings uncover a novel mechanism of glipizide as a potential cancer therapy, and also for the first time, provide direct evidence to support that treatment with glipizide may reduce the cancer risk for diabetic patients. PMID:25294818

  12. Imatinib and Dasatinib Inhibit Hemangiosarcoma and Implicate PDGFR-β and Src in Tumor Growth.

    PubMed

    Dickerson, Erin B; Marley, Kevin; Edris, Wade; Tyner, Jeffrey W; Schalk, Vidya; Macdonald, Valerie; Loriaux, Marc; Druker, Brian J; Helfand, Stuart C

    2013-04-01

    Hemangiosarcoma, a natural model of human angiosarcoma, is an aggressive vascular tumor diagnosed commonly in dogs. The documented expression of several receptor tyrosine kinases (RTKs) by these tumors makes them attractive targets for therapeutic intervention using tyrosine kinase inhibitors (TKIs). However, we possess limited knowledge of the effects of TKIs on hemangiosarcoma as well as other soft tissue sarcomas. We report here on the use of the TKIs imatinib and dasatinib in canine hemangiosarcoma and their effects on platelet-derived growth factor receptor β (PDGFR-β) and Src inhibition. Both TKIs reduced cell viability, but dasatinib was markedly more potent in this regard, mediating cytotoxic effects orders of magnitude greater than imatinib. Dasatinib also inhibited the phosphorylation of the shared PDGFR-β target at a concentration approximately 1000 times less than that needed by imatinib and effectively blocked Src phosphorylation. Both inhibitors augmented the response to doxorubicin, suggesting that clinical responses likely will be improved using both drugs in combination; however, dasatinib was significantly (P < .05) more effective in this context. Despite the higher concentrations needed in cell-based assays, imatinib significantly inhibited tumor growth (P < .05) in a tumor xenograft model, highlighting that disruption of PDGFR-β/PDGF signaling may be important in targeting the angiogenic nature of these tumors. Treatment of a dog with spontaneously occurring hemangiosarcoma established that clinically achievable doses of dasatinib may be realized in dogs and provides a means to investigate the effect of TKIs on soft tissue sarcomas in a large animal model. PMID:23544168

  13. A tissue-engineered therapeutic device inhibits tumor growth in vitro and in vivo.

    PubMed

    Sun, Ming; Wang, Miao; Chen, Muwan; Dagnaes-Hansen, Frederik; Le, Dang Quang Svend; Baatrup, Anette; Horsman, Michael R; Kjems, Jørgen; Bünger, Cody Eric

    2015-05-01

    Bone metastasis is one of the leading causes of death in breast cancer patients. The current treatment is performed as a palliative therapy and the adverse side effects can compromise the patients' quality of life. In order to both effectively treat bone metastasis and avoid the limitation of current strategies, we have invented a drug eluting scaffold with clay matrix release doxorubicin (DESCLAYMR_DOX) to mechanically support the structure after resecting the metastatic tissue while also releasing the anticancer drug doxorubicin which supplements growth inhibition and elimination of the remaining tumor cells. We have previously demonstrated that this device has the capacity to regenerate the bone and provide sustained release of the anticancer drug in vitro. In this study, we focus on the ability of the device to inhibit cancer cell growth in vitro as well as in vivo. Drug-release kinetics was investigated and the cell viability test showed that the tumor inhibitory effect is sustained for up to 4weeks in vitro. Subcutaneous implantation of DESCLAYMR_DOX in athymic mice resulted in significant growth inhibition of human tumor xenografts of breast origin and decelerated multi-organ metastasis formation. Fluorescence images, visualizing doxorubicin, showed a sustained drug release from the DESCLAYMR device in vivo. Furthermore, local use of DESCLAYMR_DOX implantation reduced the incidence of doxorubicin's cardio-toxicity. These results suggest that DESCLAYMR_DOX can be used in reconstructive surgery to support the structure after bone tumor resection and facilitate a sustained release of anticancer drugs in order to prevent tumor recurrence. PMID:25686557

  14. Selenium Induces an Anti-tumor Effect Via Inhibiting Intratumoral Angiogenesis in a Mouse Model of Transplanted Canine Mammary Tumor Cells.

    PubMed

    Li, Wenyu; Guo, Mengyao; Liu, Yuzhu; Mu, Weiwei; Deng, Ganzhen; Li, Chengye; Qiu, Changwei

    2016-06-01

    Selenium (Se) has been widely reported to possess anti-tumor effects. Angiogenesis is the formation of new blood vessels and is required to supply oxygen, nutrients, and growth factors for tumor growth, progression, and metastasis. To explore whether the anti-tumor effect of Se was associated with angiogenesis in vivo, we studied the effects of sodium selenite (Sel) and methylseleninic acid (MSA) on tumors induced by canine mammary tumor cells (CMT1211) in mice; cyclophosphamide (CTX) served as a positive control. The results showed that the Se content was significantly increased in the Sel and MSA groups. Se significantly inhibited the tumor weights and volumes. Large necrotic areas and scattered and abnormal small necrotic areas were observed in the Se treatment group. Immunofluorescence double staining showed a reduction in the microvessel density (MVD) and increment in the vessel maturation index (VMI) compared with the untreated control group. As expected, the protein and mRNA levels of the angiogenesis factors angiopoietin-2 (Ang-2), platelet-derived growth factor (PDGF), and vascular endothelial growth factor (VEGF) were decreased in the Se-treated tumors by IHC, as shown by western blotting and RT-QPCR. We also found that organic Se MSA provided stronger inhibition of tumor growth compared with inorganic sodium selenite (Sel). Altogether, our results indicated that Se exerted anti-tumor effects in vivo at least partially by inhibiting angiogenic factors. PMID:26507439

  15. An implantable microdevice to perform high-throughput in vivo drug sensitivity testing in tumors.

    PubMed

    Jonas, Oliver; Landry, Heather M; Fuller, Jason E; Santini, John T; Baselga, Jose; Tepper, Robert I; Cima, Michael J; Langer, Robert

    2015-04-22

    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

  16. 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

  17. Nanobubble Ultrasound Contrast Agents for Enhanced Delivery of Thermal Sensitizer to Tumors Undergoing Radiofrequency Ablation

    PubMed Central

    Perera, Reshani H.; Solorio, Luis; Wu, Hanping; Gangolli, Mihika; Silverman, Eric; Hernandez, Christopher; Peiris, Pubudu M.; Broome, Ann-Marie

    2013-01-01

    Purpose Pluronic has been shown to sensitize various tumor cell lines to chemotherapy and hyperthermia by altering the membrane fluidity, depleting ATP, and modulating the heat shock protein 70 expression. In our prior work, Pluronic was also used to formulate nanosized ultrasound contrast agents. In the current study we evaluate the use of these contrast agents as vehicles for image-guided delivery of Pluronic to improve outcomes of tumor radiofrequency (RF) ablation. Methods Lipid-shelled Pluronic nanobubbles were prepared and examined for size distribution, zeta potential, stability, biodistribution, accumulation of nanobubbles in the tumor, and treatment efficacy. LS174-T xenograft tumor-bearing mice were used to evaluate tumor growth suppression and measure treatment efficacy after RF ablation. Results The average diameter of Pluronic bubbles was 230 nm, and initial bubble echogenicity was 16 dB. In vitro, cells exposed to Pluronic nanobubbles exhibited low cytotoxicity in the absence of ultrasound, even if heat (43°C) was applied. When the cells were exposed to Pluronic nanobubbles, heat, and ultrasound; viability was significantly reduced. In vivo, tumors treated with ultrasound-modulated nanobubbles prior to RF ablation showed a significant reduction in growth compared to the RF alone (P<0.05). Conclusion Lipid and Pluronic-shelled, echogenic nanobubbles combined with ultrasound modulation can serve as an effective theranostic method for sensitization of tumors to RF ablation. PMID:23943542

  18. Augmented IFN-γ and TNF-α Induced by Probiotic Bacteria in NK Cells Mediate Differentiation of Stem-Like Tumors Leading to Inhibition of Tumor Growth and Reduction in Inflammatory Cytokine Release; Regulation by IL-10

    PubMed Central

    Bui, Vickie T.; Tseng, Han-Ching; Kozlowska, Anna; Maung, Phyu Ou; Kaur, Kawaljit; Topchyan, Paytsar; Jewett, Anahid

    2015-01-01

    Our previous reports demonstrated that the magnitude of natural killer (NK) cell-mediated cytotoxicity correlate directly with the stage and level of differentiation of tumor cells. In addition, we have shown previously that activated NK cells inhibit growth of cancer cells through induction of differentiation, resulting in the resistance of tumor cells to NK cell-mediated cytotoxicity through secreted cytokines, as well as direct NK-tumor cell contact. In this report, we show that in comparison to IL-2 + anti-CD16mAb-treated NK cells, activation of NK cells by probiotic bacteria (sAJ2) in combination with IL-2 and anti-CD16mAb substantially decreases tumor growth and induces maturation, differentiation, and resistance of oral squamous cancer stem cells, MIA PaCa-2 stem-like/poorly differentiated pancreatic tumors, and healthy stem cells of apical papillae through increased secretion of IFN-γ and TNF-α, as well as direct NK-tumor cell contact. Tumor resistance to NK cell-mediated killing induced by IL-2 + anti-CD16mAb + sAJ2-treated NK cells is induced by combination of IFN-γ and TNF-α since antibodies to both, and not each cytokine alone, were able to restore tumor sensitivity to NK cells. Increased surface expression of CD54, B7H1, and MHC-I on NK-differentiated tumors was mediated by IFN-γ since the addition of anti-IFN-γ abolished their increase and restored the ability of NK cells to trigger cytokine and chemokine release; whereas differentiated tumors inhibited cytokine release by the NK cells. Monocytes synergize with NK cells in the presence of probiotic bacteria to induce regulated differentiation of stem cells through secretion of IL-10 resulting in resistance to NK cell-mediated cytotoxicity and inhibition of cytokine release. Therefore, probiotic bacteria condition activated NK cells to provide augmented differentiation of cancer stem cells resulting in inhibition of tumor growth, and decreased inflammatory cytokine release. PMID

  19. Inhibition of NF-κB and DNA double-strand break repair by DMAPT sensitizes non-small-cell lung cancers to X-rays.

    PubMed

    Estabrook, Neil C; Chin-Sinex, Helen; Borgmann, Anthony J; Dhaemers, Ryan M; Shapiro, Ronald H; Gilley, David; Huda, Nazmul; Crooks, Peter; Sweeney, Christopher; Mendonca, Marc S

    2011-12-15

    We investigated the efficacy and mechanism of dimethylaminoparthenolide (DMAPT), an NF-κB inhibitor, to sensitize human lung cancer cells to X-ray killing in vitro and in vivo. We tested whether DMAPT increased the effectiveness of single and fractionated X-ray treatment through inhibition of NF-κB and/or DNA double-strand break (DSB) repair. Treatment with DMAPT decreased plating efficiency, inhibited constitutive and radiation-induced NF-κB binding activity, and enhanced radiation-induced cell killing by dose modification factors of 1.8 and 1.4 in vitro. X-ray fractionation demonstrated that DMAPT inhibited split-dose recovery/repair, and neutral DNA comet assays confirmed that DMAPT altered the fast and slow components of X-ray-induced DNA DSB repair. Knockdown of the NF-κB family member p65 by siRNA increased radiation sensitivity and completely inhibited split-dose recovery in a manner very similar to DMAPT treatment. The data suggest a link between inhibition of NF-κB and inhibition of DSB repair by DMAPT that leads to enhancement of X-ray-induced cell killing in vitro in non-small-cell lung cancer cells. Studies of A549 tumor xenografts in nude mice demonstrated that DMAPT enhanced X-ray-induced tumor growth delay in vivo. PMID:22019440

  20. Sapodilla plum (Achras sapota) induces apoptosis in cancer cell lines and inhibits tumor progression in mice.

    PubMed

    Srivastava, Mrinal; Hegde, Mahesh; Chiruvella, Kishore K; Koroth, Jinsha; Bhattacharya, Souvari; Choudhary, Bibha; Raghavan, Sathees C

    2014-01-01

    Intake of fruits rich in antioxidants in daily diet is suggested to be cancer preventive. Sapota is a tropical fruit grown and consumed extensively in several countries including India and Mexico. Here we show that methanolic extracts of Sapota fruit (MESF) induces cytotoxicity in a dose-dependent manner in cancer cell lines. Cell cycle analysis suggested activation of apoptosis, without arresting cell cycle progression. Annexin V-propidium iodide double-staining demonstrated that Sapota fruit extracts potentiate apoptosis rather than necrosis in cancer cells. Loss of mitochondrial membrane potential, upregulation of proapoptotic proteins, activation of MCL-1, PARP-1, and Caspase 9 suggest that MESF treatment leads to activation of mitochondrial pathway of apoptosis. More importantly, we show that MESF treatment leads to significant inhibition of tumor growth and a 3-fold increase in the life span of tumor bearing animals compared to untreated tumor mice. PMID:25142835

  1. Estrogen Represses Hepatocellular Carcinoma (HCC) Growth via Inhibiting Alternative Activation of Tumor-associated Macrophages (TAMs)*

    PubMed Central

    Yang, Weiwei; Lu, Yan; Xu, Yichen; Xu, Lizhi; Zheng, Wei; Wu, Yuanyuan; Li, Long; Shen, Pingping

    2012-01-01

    Hepatocarcinoma cancer (HCC), one of the most malignant cancers, occurs significantly more often in men than in women; however, little is known about its underlying molecular mechanisms. Here we identified that 17β-estradiol (E2) could suppress tumor growth via regulating the polarization of macrophages. We showed that E2 re-administration reduced tumor growth in orthotopic and ectopic mice HCC models. E2 functioned as a suppressor for macrophage alternative activation and tumor progression by keeping estrogen receptor β (ERβ) away from interacting with ATP5J (also known as ATPase-coupling factor 6), a part of ATPase, thus inhibiting the JAK1-STAT6 signaling pathway. These studies introduce a novel mechanism for suppressing male-predominant HCC. PMID:22908233

  2. Fufang Kushen injection inhibits sarcoma growth and tumor-induced hyperalgesia via TRPV1 signaling pathways.

    PubMed

    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

    2014-12-28

    Cancer pain is a deleterious consequence of tumor growth and related inflammation. Opioids and anti-inflammatory 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

  3. Sapodilla Plum (Achras sapota) Induces Apoptosis in Cancer Cell Lines and Inhibits Tumor Progression in Mice

    PubMed Central

    Srivastava, Mrinal; Hegde, Mahesh; Chiruvella, Kishore K.; Koroth, Jinsha; Bhattacharya, Souvari; Choudhary, Bibha; Raghavan, Sathees C.

    2014-01-01

    Intake of fruits rich in antioxidants in daily diet is suggested to be cancer preventive. Sapota is a tropical fruit grown and consumed extensively in several countries including India and Mexico. Here we show that methanolic extracts of Sapota fruit (MESF) induces cytotoxicity in a dose-dependent manner in cancer cell lines. Cell cycle analysis suggested activation of apoptosis, without arresting cell cycle progression. Annexin V-propidium iodide double-staining demonstrated that Sapota fruit extracts potentiate apoptosis rather than necrosis in cancer cells. Loss of mitochondrial membrane potential, upregulation of proapoptotic proteins, activation of MCL-1, PARP-1, and Caspase 9 suggest that MESF treatment leads to activation of mitochondrial pathway of apoptosis. More importantly, we show that MESF treatment leads to significant inhibition of tumor growth and a 3-fold increase in the life span of tumor bearing animals compared to untreated tumor mice. PMID:25142835

  4. A Novel Potent Oral Series of VEGFR2 Inhibitors Abrogate Tumor Growth by Inhibiting Angiogenesis.

    PubMed

    Bold, Guido; Schnell, Christian; Furet, Pascal; McSheehy, Paul; Brüggen, Josef; Mestan, Jürgen; Manley, Paul W; Drückes, Peter; Burglin, Marion; Dürler, Ursula; Loretan, Jacqueline; Reuter, Robert; Wartmann, Markus; Theuer, Andreas; Bauer-Probst, Beatrice; Martiny-Baron, Georg; Allegrini, Peter; Goepfert, Arnaud; Wood, Jeanette; Littlewood-Evans, Amanda

    2016-01-14

    This paper describes the identification of 6-(pyrimidin-4-yloxy)-naphthalene-1-carboxamides as a new class of potent and selective human vascular endothelial growth factor receptor 2 (VEGFR2) tyrosine kinase inhibitors. In biochemical and cellular assays, the compounds exhibit single-digit nanomolar potency toward VEGFR2. Compounds of this series show good exposure in rodents when dosed orally. They potently inhibit VEGF-driven angiogenesis in a chamber model and rodent tumor models at daily doses of less than 3 mg/kg by targeting the tumor vasculature as demonstrated by ELISA for TIE-2 in lysates or by immunohistochemical analysis. This novel series of compounds shows a potential for the treatment of solid tumors and other diseases where angiogenesis plays an important role. PMID:26629594

  5. Inhibition of Receptor Signaling and of Glioblastoma-derived Tumor Growth by a Novel PDGFRβ Aptamer

    PubMed Central

    Camorani, Simona; Esposito, Carla L; Rienzo, Anna; Catuogno, Silvia; Iaboni, Margherita; Condorelli, Gerolama; de Franciscis, Vittorio; Cerchia, Laura

    2014-01-01

    Platelet-derived growth factor receptor β (PDGFRβ) is a cell-surface tyrosine kinase receptor implicated in several cellular processes including proliferation, migration, and angiogenesis. It represents a compelling therapeutic target in many human tumors, including glioma. A number of tyrosine kinase inhibitors under development as antitumor agents have been found to inhibit PDGFRβ. However, they are not selective as they present multiple tyrosine kinase targets. Here, we report a novel PDGFRβ-specific antagonist represented by a nuclease-resistant RNA-aptamer, named Gint4.T. This aptamer is able to specifically bind to the human PDGFRβ ectodomain (Kd: 9.6 nmol/l) causing a strong inhibition of ligand-dependent receptor activation and of downstream signaling in cell lines and primary cultures of human glioblastoma cells. Moreover, Gint4.T aptamer drastically inhibits cell migration and proliferation, induces differentiation, and blocks tumor growth in vivo. In addition, Gint4.T aptamer prevents PDGFRβ heterodimerization with and resultant transactivation of epidermal growth factor receptor. As a result, the combination of Gint4.T and an epidermal growth factor receptor–targeted aptamer is better at slowing tumor growth than either single aptamer alone. These findings reveal Gint4.T as a PDGFRβ-drug candidate with translational potential. PMID:24566984

  6. Metformin inhibits prostate cancer cell proliferation, migration, and tumor growth through upregulation of PEDF expression.

    PubMed

    Chen, Xiaowan; Li, Chenli; He, Tiantian; Mao, Jiating; Li, Chunmei; Lyu, Jianxin; Meng, Qing H

    2016-05-01

    Metformin has been reported to inhibit the growth of various types of cancers, including prostate cancer. Yet the mode of anti-cancer action of metformin and the underlying mechanisms remain not fully elucidated. We hypothesized that the antitumorigenic effects of metformin are mediated through upregulation of pigment epithelium-derived factor (PEDF) expression in prostate cancer cells. In this report, metformin treatment significantly inhibited the proliferation and colony formation of prostate cancer cells, in a dose- and time-dependent manner. Meanwhile, Metformin markedly suppressed migration and invasion and induced apoptosis of both LNCaP and PC3 cancer cells. Metformin also reduced PC3 tumor growth in BALB/c nude mice in vivo. Furthermore, metformin treatment was associated with higher PEDF expression in both prostate cancer cells and tumor tissue. Taken together, metformin inhibits prostate cancer cell proliferation, migration, invasion and tumor growth, and these activities are mediated by upregulation of PEDF expression. These findings provide a novel insight into the molecular functions of metformin as an anticancer agent. PMID:26987032

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

    PubMed

    Chen, Kuan-Hui Ethan; Walker, Ameae M

    2016-06-01

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

  8. Metformin inhibits tumor growth by regulating multiple miRNAs in human cholangiocarcinoma.

    PubMed

    Jiang, Xingming; Ma, Ning; Wang, Dayong; Li, Fuyuan; He, Rongzhang; Li, Dongliang; Zhao, Ruiqi; Zhou, Qingxin; Wang, Yimin; Zhang, Fumin; Wan, Ming; Kang, Pengcheng; Gao, Xu; Cui, Yunfu

    2015-02-20

    The antidiabetic drug metformin exerts antineoplastic effects in many types of malignancies, however the effect of metformin on cholangiocarcinoma (CCA) still remains unclear. In the present study, we investigated that metformin treatment was closely associated with the clinicopathologic characteristics and improved postoperative survival of CCA patients. Metformin inhibited CCA tumor growth by cell cycle arrest in vitro and in vivo. We explored that the expression of six miRNAs (mir124, 182, 27b, let7b, 221 and 181a), which could directly target cell-cycle-regulatory genes, was altered by metformin in vitro and in vivo. These miRNAs were dysregulated in cholangiocarcinoma and promoted the CCA genesis and metformin exactly modulated these carcinogenic miRNAs expression to arrest the cell cycle and inhibit the proliferation. Meanwhile, these miRNAs expression changes correlated with the tumor volume and postoperative survival of CCA patients and could be used to predict the prognosis. Further we confirmed that metformin upregulated Drosha to modulate these miRNAs expression. Our results elucidated that metformin inhibited CCA tumor growth via the regulation of Drosha-mediated multiple carcinogenic miRNAs expression and comprehensive evaluation of these miRNAs expression could be more efficient to predict the prognosis. Moreover, metformin might be a quite promising strategy for CCA prevention and treatment. PMID:25605008

  9. A polypeptide from shark troponin I can inhibit angiogenesis and tumor growth.

    PubMed

    Xie, Qiuling; Yao, Sheng; Chen, Xiaojia; Xu, Lihui; Peng, Wendan; Zhang, Ling; Zhang, Qihao; Liang, Xu-Fang; Hong, An

    2012-02-01

    The shark troponin I gene (TnI) was found for the first time in this study to inhibit endothelial cell proliferation and angiogenesis. This shark TnI had 68.9% amino acid homology with human TnI, whereas the polypeptide from Lys91 to Leu123, which is thought to be the active site of TnI, had 78.8% homology with the corresponding fragment of human TnI. However, the polypeptide of shark had higher activity to inhibit the proliferation of HUVEC and tumor cell lines than that of human TnI. To investigate the anti-angiogenesis and anti-tumor effect of the shark TnI polypeptide, the DNA sequence of polypeptide (Lys91-Leu123) of white-spot catshark TnI(psTnI) was cloned and fused with the His-SUMO cDNA, followed by expression in Escherichia coli. After its purification by Ni(2+) affinity chromatography, the fusion His-SUMO-psTnI protein was digested with the SUMO enzyme to release psTnI. The inhibitory ability of this recombinant shark TnI polypeptide for angiogenesis was confirmed by chicken embryo allantoic membrane (CAM) test and IHC analysis. It was also found by breast carcinoma xenograft study in Balb/c mice that this polypeptide could inhibit tumor growth in vivo. PMID:21750912

  10. The effects of telomerase inhibition on prostate tumor-initiating cells.

    PubMed

    Marian, Calin O; Wright, Woodring E; Shay, Jerry W

    2010-07-15

    Prostate cancer is the most common malignancy in men, and patients with metastatic disease have poor outcome even with the most advanced therapeutic approaches. Most cancer therapies target the bulk tumor cells, but may leave intact a small population of tumor-initiating cells (TICs), which are believed to be responsible for the subsequent relapse and metastasis. Using specific surface markers (CD44, integrin alpha(2)beta(1) and CD133), Hoechst 33342 dye exclusion, and holoclone formation, we isolated TICs from a panel of prostate cancer cell lines (DU145, C4-2 and LNCaP). We have found that prostate TICs have significant telomerase activity which is inhibited by imetelstat sodium (GRN163L), a new telomerase antagonist that is currently in Phase I/II clinical trials for several hematological and solid tumor malignancies. Prostate TICs telomeres were of similar average length to the telomeres of the main population of cells and significant telomere shortening was detected in prostate TICs as a result of imetelstat treatment. These findings suggest that telomerase inhibition therapy may be able to efficiently target the prostate TICs in addition to the bulk tumor cells, providing new opportunities for combination therapies. PMID:19908230

  11. Berberine inhibits human tongue squamous carcinoma cancer tumor growth in a murine xenograft model.

    PubMed

    Ho, Yung-Tsuan; Yang, Jai-Sing; Lu, Chi-Cheng; Chiang, Jo-Hua; Li, Tsai-Chung; Lin, Jen-Jyh; Lai, Kuang-Chi; Liao, Ching-Lung; Lin, Jaung-Geng; Chung, Jing-Gung

    2009-09-01

    Our primary studies showed that berberine induced apoptosis in human tongue cancer SCC-4 cells in vitro. But there is no report to show berberine inhibited SCC-4 cancer cells in vivo on a murine xenograft animal model. SCC-4 tumor cells were implanted into mice and groups of mice were treated with vehicle, berberine (10mg/kg of body weight) and doxorubicin (4mg/kg of body weight). The tested agents were injected once per four days intraperitoneally (i.p.), with treatment starting 4 weeks prior to cells inoculation. Treatment with 4mg/kg of doxorubicin or with 10mg/kg of berberine resulted in a reduction in tumor incidence. Tumor size in xenograft mice treated with 10mg/kg berberine was significantly smaller than that in the control group. Our findings indicated that berbeirne inhibits tumor growth in a xenograft animal model. Therefore, berberine may represent a tongue cancer preventive agent and can be used in clinic. PMID:19303753

  12. A humanized anti-DLL4 antibody promotes dysfunctional angiogenesis and inhibits breast tumor growth

    PubMed Central

    Jia, Xuelian; Wang, Wenyi; Xu, Zhuobin; Wang, Shijing; Wang, Tong; Wang, Min; Wu, Min

    2016-01-01

    Blockage of Delta-like 4 (DLL4)-directed Notch signaling induces excessive tip cell formation and endothelial proliferation resulting in dysfunctional angiogenesis in tumors. MMGZ01, as a murine anti-human DLL4 monoclonal antibody, specifically binds to human DLL4 and blocks Notch pathway. Here, the structure of MMGZ01 variable fragment (Fv) was established and framework region (FR) residues which supported complementarily determining region (CDR) loop conformation were identified. Important residues interactions were also identified through docking MMGZ01 Fv with antigen epitope in DLL4. To humanize the murine antibody, we modified MMGZ01 Fv through CDR grafting and the reconstructed antibody (H3L2) maintained similar structure and binding affinity to parental MMGZ01 after back mutation of 12 canonical murine residues in the FRs. Meanwhile, H3L2 promoted human umbilical vein endothelial cell (HUVEC) proliferation through inhibiting DLL4-directed Notch pathway. Moreover, in MDA-MB-231-bearing nude mice, H3L2 induced dysfunctional angiogenesis and tumor cell apoptosis and showed superior anti-tumor activity. In conclusion, H3L2 is an ideal humanized antibody that inhibits tumor growth through targeting DLL4-Notch pathway and has attracting potentials for clinical applications. PMID:27301650

  13. A recombinant decoy comprising EGFR and ErbB-4 inhibits tumor growth and metastasis

    PubMed Central

    Lindzen, Moshit; Carvalho, Silvia; Starr, Alex; Ben-Chetrit, Nir; Pradeep, Chaluvally-Raghavan; Köstler, Wolfgang J.; Rabinkov, Aaron; Lavi, Sara; Bacus, Sarah S.; Yarden, Yosef

    2011-01-01

    EGF-like growth factors control tumor progression, as well as evasion from the toxic effects of chemotherapy. Accordingly, antibodies targeting the cognate receptors, such as EGFR/ErbB-1 and the co-receptor HER2/ErbB-2, are widely used to treat cancer patients, but agents that target the EGF-like growth factors are not available. To circumvent the existence of 11 distinct ErbB ligands, we constructed a soluble fusion protein (hereinafter: TRAP-Fc) comprising truncated extracellular domains of EGFR/ErbB-1 and ErbB-4. The recombinant TRAP-Fc retained high affinity ligand binding to EGF-like growth factors and partially inhibited growth of a variety of cultured tumor cells. Consistently, TRAP-Fc displayed an inhibitory effect in xenograft models of human cancer, as well as synergy with chemotherapy. Additionally, TRAP-Fc inhibited invasive growth of mammary tumor cells and reduced their metastatic seeding in the lungs of animals. Taken together, the activities displayed by TRAP-Fc reinforce critical roles of EGF-like growth factors in tumor progression, and they warrant further tests of TRAP-Fc in pre-clinical models. PMID:22105361

  14. Activation of the Aryl Hydrocarbon Receptor by TCDD Inhibits Senescence: A Tumor Promoting Event?

    PubMed Central

    Ray, S.; Swanson, H.I.

    2009-01-01

    Activation of the aryl hydrocarbon receptor (AHR) 1 by the agonist, 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) has been shown to promote tumor formation in both liver and skin. In the liver, but not the skin, the AHR-mediated events that contribute to TCDD’s tumor promoting activities have been studied in some detail and are thought to involve perturbation of cell fate processes. However, studies performed using cultured cells have often resulted in apparent contradictory results indicating that the impact of TCDD on cell fate processes may be cell context dependent. We and others have shown that in primary cultured keratinocytes TCDD increases post-confluent proliferation and increases late differentiation. Further, our studies performed in these cells indicate that TCDD can also inhibit culture-induced senescence. While senescence, a permanent cell cycle arrest, is emerging as an important process regulated by oncogenes and considered to be of therapeutic importance, its role with respect to TCDD/AHR mediated tumor promotion has not been fully considered. The intent of this article is to focus primarily on senescence as a cell process relevant to skin tumorigenesis and explore the idea that the inhibition of senescence by TCDD could be an important mechanism by which it may exert its tumor promoting effects in the skin. PMID:19100242

  15. A humanized anti-DLL4 antibody promotes dysfunctional angiogenesis and inhibits breast tumor growth.

    PubMed

    Jia, Xuelian; Wang, Wenyi; Xu, Zhuobin; Wang, Shijing; Wang, Tong; Wang, Min; Wu, Min

    2016-01-01

    Blockage of Delta-like 4 (DLL4)-directed Notch signaling induces excessive tip cell formation and endothelial proliferation resulting in dysfunctional angiogenesis in tumors. MMGZ01, as a murine anti-human DLL4 monoclonal antibody, specifically binds to human DLL4 and blocks Notch pathway. Here, the structure of MMGZ01 variable fragment (Fv) was established and framework region (FR) residues which supported complementarily determining region (CDR) loop conformation were identified. Important residues interactions were also identified through docking MMGZ01 Fv with antigen epitope in DLL4. To humanize the murine antibody, we modified MMGZ01 Fv through CDR grafting and the reconstructed antibody (H3L2) maintained similar structure and binding affinity to parental MMGZ01 after back mutation of 12 canonical murine residues in the FRs. Meanwhile, H3L2 promoted human umbilical vein endothelial cell (HUVEC) proliferation through inhibiting DLL4-directed Notch pathway. Moreover, in MDA-MB-231-bearing nude mice, H3L2 induced dysfunctional angiogenesis and tumor cell apoptosis and showed superior anti-tumor activity. In conclusion, H3L2 is an ideal humanized antibody that inhibits tumor growth through targeting DLL4-Notch pathway and has attracting potentials for clinical applications. PMID:27301650

  16. Itraconazole inhibits angiogenesis and tumor growth in non-small cell lung cancer

    PubMed Central

    Aftab, Blake T.; Dobromilskaya, Irina; Liu, Jun O.; Rudin, Charles M.

    2011-01-01

    The anti-angiogenic agent bevacizumab has been approved for the treatment of non-small cell lung cancer, although the survival benefit associated with this agent is marginal, and toxicities and cost are substantial. A recent screen for selective inhibitors of endothelial cell proliferation identified the oral anti-fungal drug itraconazole as a novel agent with potential anti-angiogenic activity. Here we define and characterize the anti-angiogenic and anti-cancer activities of itraconazole in relevant preclinical models of angiogenesis and lung cancer. Itraconazole consistently demonstrated potent, specific, and dose-dependent inhibition of endothelial cell proliferation, migration, and tube formation in response to both vascular endothelial growth factor (VEGF)- and basic fibroblast growth factor (bFGF)-mediated angiogenic stimulation. In vivo, using primary xenograft models of human non-small cell lung cancer, oral itraconazole showed single agent growth-inhibitory activity associated with induction of tumor HIF1α expression and marked inhibition of tumor vascularity. Itraconazole significantly enhanced the anti-tumor efficacy of the chemotherapeutic agent cisplatin in the same model systems. Taken together, these data suggest that itraconazole has potent and selective inhibitory activity against multiple key aspects of tumor-associated angiogenesis in vitro and in vivo, and strongly support clinical translation of its use. Based on these observations we have initiated a randomized phase II study comparing the efficacy of standard cytotoxic therapy with or without daily oral itraconazole in patients with recurrent metastatic non-small cell lung cancer. PMID:21896639

  17. Dihydrolipoic acid inhibits skin tumor promotion through anti-inflammation and anti-oxidation.

    PubMed

    Ho, Yuan-Soon; Lai, Ching-Shu; Liu, Hsin-I; Ho, Sheng-Yow; Tai, Chein; Pan, Min-Hsiung; Wang, Ying-Jan

    2007-06-01

    alpha-Lipoic acid (LA) has been intensely investigated as a therapeutic agent for several diseases, including hepatic disorder and diabetic polyneuropathy. However, the effects of LA or its reduced form, dihydrolipoic acid (DHLA), on cancer chemoprevention has never been reported. In the present study, we examined the effects of DHLA/LA on the production of nitric oxide (NO) by inducible NO synthase (iNOS) and the formation of prostaglandin E2 (PGE(2)) by cyclooxygenase-2 (COX-2), two important mediators associated with inflammation. DHLA/LA significantly inhibited lipopolysaccharide (LPS)-induced NO and PGE(2) formation in RAW 264.7 cells. Meanwhile, treatment with DHLA/LA suppressed the expression of iNOS protein but, unexpectedly, did not affect or increase the expression of COX-2 protein. The in vivo anti-inflammatory and antitumor-promoting activities were evaluated by a topical 12-O-tetradecanoylphorbol 13-acetate (TPA) application to mouse skin with measurement of edema formation, epidermal thickness and hydrogen peroxide production. DHLA significantly inhibited the priming and activation stages of skin inflammation induced by a double TPA application, by decreasing the inflammatory parameters. Furthermore, DHLA inhibited DMBA (0.3 micromol)/TPA (2.0 nmol)-induced skin tumor formation by reducing the tumor incidence and tumor multiplicity. When applied topically onto the shaven backs of mice prior to TPA, DHLA markedly inhibited the expression of iNOS protein. DHLA also strongly and directly inhibited COX-2 activity. These results suggest that DHLA can be a possible chemopreventive agent in inflammation-associated tumorigenesis. PMID:17403519

  18. Antagonism of sphingosine-1-phosphate receptors by FTY720 inhibits angiogenesis and tumor vascularization.

    PubMed

    LaMontagne, Kenneth; Littlewood-Evans, Amanda; Schnell, Christian; O'Reilly, Terence; Wyder, Lorenza; Sanchez, Teresa; Probst, Beatrice; Butler, Jeannene; Wood, Alexander; Liau, Gene; Billy, Eric; Theuer, Andreas; Hla, Timothy; Wood, Jeanette

    2006-01-01

    FTY720, a potent immunomodulator, becomes phosphorylated in vivo (FTY-P) and interacts with sphingosine-1-phosphate (S1P) receptors. Recent studies showed that FTY-P affects vascular endothelial growth factor (VEGF)-induced vascular permeability, an important aspect of angiogenesis. We show here that FTY720 has antiangiogenic activity, potently abrogating VEGF- and S1P-induced angiogenesis in vivo in growth factor implant and corneal models. FTY720 administration tended to inhibit primary and significantly inhibited metastatic tumor growth in a mouse model of melanoma growth. In combination with a VEGFR tyrosine kinase inhibitor PTK787/ZK222584, FTY720 showed some additional benefit. FTY720 markedly inhibited tumor-associated angiogenesis, and this was accompanied by decreased tumor cell proliferation and increased apoptosis. In transfected HEK293 cells, FTY-P internalized S1P1 receptors, inhibited their recycling to the cell surface, and desensitized S1P receptor function. Both FTY720 and FTY-P apparently failed to impede VEGF-produced increases in mitogen-activated protein kinase activity in human umbilical vascular endothelial cells (HUVEC), and unlike its activity in causing S1PR internalization, FTY-P did not result in a decrease of surface VEGFR2 levels in HUVEC cells. Pretreatment with FTY720 or FTY-P prevented S1P-induced Ca2+ mobilization and migration in vascular endothelial cells. These data show that functional antagonism of vascular S1P receptors by FTY720 potently inhibits angiogenesis; therefore, this may provide a novel therapeutic approach for pathologic conditions with dysregulated angiogenesis. PMID:16397235

  19. Small rho GTPases mediate tumor-induced inhibition of endocytic activity of dendritic cells.

    PubMed

    Tourkova, Irina L; Shurin, Galina V; Wei, Sheng; Shurin, Michael R

    2007-06-15

    The generation, maturation, and function of dendritic cells (DC) have been shown to be markedly compromised in the tumor microenvironment in animals and humans. However, the molecular mechanisms and intracellular pathways involved in the regulation of the DC system in cancer are not yet fully understood. Recently, we have reported on the role of the small Rho GTPase family members Cdc42, Rac1, and RhoA in regulating DC adherence, motility, and Ag presentation. To investigate involvement of small Rho GTPases in dysregulation of DC function by tumors, we next evaluated how Cdc42, Rac1, and RhoA regulated endocytic activity of DC in the tumor microenvironment. We revealed a decreased uptake of dextran 40 and polystyrene beads by DC generated in the presence of different tumor cell lines, including RM1 prostate, MC38 colon, 3LL lung, and B7E3 oral squamous cell carcinomas in vitro and by DC prepared from tumor-bearing mice ex vivo. Impaired endocytic activity of DC cocultured with tumor cells was associated with decreased levels of active Cdc42 and Rac1. Transduction of DC with the dominant negative Cdc42 and Rac1 genes also led to reduced phagocytosis and receptor-mediated endocytosis. Furthermore, transduction of DC with the constitutively active Cdc42 and Rac1 genes restored endocytic activity of DC that was inhibited by the tumors. Thus, our results suggest that tumor-induced dysregulation of endocytic activity of DC is mediated by reduced activity of several members of the small Rho GTPase family, which might serve as new targets for improving the efficacy of DC vaccines. PMID:17548616

  20. Extract of Cordyceps militaris inhibits angiogenesis and suppresses tumor growth of human malignant melanoma cells.

    PubMed

    Ruma, I Made Winarsa; Putranto, Endy Widya; Kondo, Eisaku; Watanabe, Risayo; Saito, Ken; Inoue, Yusuke; Yamamoto, Ken-Ichi; Nakata, Susumu; Kaihata, Masaji; Murata, Hitoshi; Sakaguchi, Masakiyo

    2014-07-01

    Angiogenesis is essential for tumor development and metastasis. Among several angiogenic factors, vascular endothelial growth factor receptor (VEGF) is important for tumor-derived angiogenesis and commonly overexpressed in solid tumors. Thus, many antitumor strategies targeting VEGF have been developed to inhibit cancer angiogenesis, offering insights into the successful treatment of solid cancers. However, there are a number of issues such as harmful effects on normal vascularity in clinical trials. Taking this into consideration, we employed Cordyceps militaris as an antitumor approach due to its biological safety in vivo. The herbal medicinal mushroom Cordyceps militaris has been reported to show potential anticancer properties including anti-angiogenic capacity; however, its concrete properties have yet to be fully demonstrated. In this study, we aimed to elucidate the biological role of Cordyceps militaris extract in tumor cells, especially in regulating angiogenesis and tumor growth of a human malignant melanoma cell line. We demonstrated that Cordyceps militaris extract remarkably suppressed tumor growth via induction of apoptotic cell death in culture that links to the abrogation of VEGF production in melanoma cells. This was followed by mitigation of Akt1 and GSK-3β activation, while p38α phosphorylation levels were increased. Extract treatment in mouse model xenografted with human melanoma cells resulted in a dramatic antitumor effect with down-regulation of VEGF expression. The results suggest that suppression of tumor growth by Cordyceps militaris extract is, at least, mediated by its anti-angiogenicity and apoptosis induction capacities. Cordyceps militaris extract may be a potent antitumor herbal drug for solid tumors. PMID:24789042

  1. Tumor promotion and inhibition by phenobarbital in livers of conditional Apc-deficient mice.

    PubMed

    Braeuning, Albert; Gavrilov, Alina; Geissler, Miriam; Wenz, Christine; Colnot, Sabine; Templin, Markus F; Metzger, Ute; Römer, Michael; Zell, Andreas; Schwarz, Michael

    2016-06-01

    Activation of Wnt/β-catenin signaling is important for human and rodent hepatocarcinogenesis. In mice, the tumor promoter phenobarbital (PB) selects for hepatocellular tumors with activating β-catenin mutations via constitutive androstane receptor activation. PB-dependent tumor promotion was studied in mice with genetic inactivation of Apc, a negative regulator of β-catenin, to circumvent the problem of randomly induced mutations by chemical initiators and to allow monitoring of PB- and Wnt/β-catenin-dependent tumorigenesis in the absence of unknown genomic alterations. Moreover, the study was designed to investigate PB-induced proliferation of liver cells with activated β-catenin. PB treatment provided Apc-deficient hepatocytes with only a minor proliferative advantage, and additional connexin 32 deficiency did not affect the proliferative response. PB significantly promoted the outgrowth of Apc-deficient hepatocellular adenoma (HCA), but simultaneously inhibited the formation of Apc-deficient hepatocellular carcinoma (HCC). The probability of tumor promotion by PB was calculated to be much lower for hepatocytes with loss of Apc, as compared to mutational β-catenin activation. Comprehensive transcriptomic and phosphoproteomic characterization of HCA and HCC revealed molecular details of the two tumor types. HCC were characterized by a loss of differentiated hepatocellular gene expression, enhanced proliferative signaling, and massive over-activation of Wnt/β-catenin signaling. In conclusion, PB exerts a dual role in liver tumor formation by promoting the growth of HCA but inhibiting the growth of HCC. Data demonstrate that one and the same compound can produce opposite effects on hepatocarcinogenesis, depending on context, highlighting the necessity to develop a more differentiated view on the tumorigenicity of this model compound. PMID:26838046

  2. [Pulsed electric fields inhibit tumor growth but induce myocardial injury of melanoma-bearing mice].

    PubMed

    Pan, Fengying; Wu, Sha; Wang, Xiaoxu; Zhang, Xiaogang

    2016-07-01

    Objective To investigate the tumor inhibiting effect of pulsed electric fields (PEFs) on melanoma-bearing mice, and understand its influence on myocardial cells and cardial electrical activity. Methods The melanoma models of the BALB/c mice were established by subcutaneously injecting B16 melanoma cells. These mice were randomly divided into four groups. The treated groups received pulsed electric stimulation at pulse width of 1, 3, 5 ms, with field strength of 100 V/cm and frequency of 10 Hz for 10 minutes daily in 15 consecutive days. ECG of mice was recorded. Tumor volume was measured with vernier caliper. Morphological changes of tumors were observed by HE staining. The expression of proliferating cell nuclear antigen (PCNA) mRNA was tested by real-time quantitative PCR, and the expression of PCNA protein was detected by immunofluorescence histochemistry. The ultrastructural changes of the cardiac tissues were observed by transmission electron microscopy (TEM). The serum levels of cardial troponin T (cTnT) and creatine kinase isoenzyme MB (CK-MB) were detected by ELISA. Results Compared with the control group, tumor volumes in all treated groups were reduced 7 days after PEFs treatment; more melanin granules in tumor cells were found in the treated groups; the expressions of PCNA mRNA and protein were down-regulated in all treated groups, and there were greater changes in the groups receiving the bigger pulse width. Myocardial injury was found in 3 ms group and 5 ms group, and the expressions of cTnT and CK-MB were significantly higher than those in the control group. Conclusion PEFs can inhibit tumor growth in melanoma-bearing mice. Increase of pulse width will aggravate myocardial injury. PMID:27363271

  3. Extract of Vernonia condensata, Inhibits Tumor Progression and Improves Survival of Tumor-allograft Bearing Mouse.

    PubMed

    Thomas, Elizabeth; Gopalakrishnan, Vidya; Somasagara, Ranganatha R; Choudhary, Bibha; Raghavan, Sathees C

    2016-01-01

    Medicinal plants are considered as one of the ideal sources for cancer therapy due to their bioactive contents and low toxicity to humans. Vernonia genus is one of the common medicinal plants, which has wide spread usage in food and medicine. However, there are limited studies to explore its anticancer properties. In the current study, we have used Vernonia condensata, to explore its anticancer activity using various approaches. Here, we show that extract prepared from Vernonia condensata (VCE) exhibits cytotoxic properties against various cancer cells in a dose- and time-dependent manner. Interestingly, when treated with VCE, there was no significant cytotoxicity in peripheral blood mononuclear cells (PBMCs). Flow cytometry analysis revealed that although VCE induced cell death, arrest was not observed. VCE treatment led to disruption of mitochondrial membrane potential in a concentration dependent manner resulting in activation of apoptosis culminating in cell death. Immunoblotting studies revealed that VCE activated intrinsic pathway of apoptosis. More importantly, VCE treatment resulted in tumor regression leading to significant enhancement in life span in treated mice, without showing any detectable side effects. Therefore, for the first time our study reveals the potential of extract from Vernonia condensata to be used as an anticancer agent. PMID:27009490

  4. Extract of Vernonia condensata, Inhibits Tumor Progression and Improves Survival of Tumor-allograft Bearing Mouse

    PubMed Central

    Thomas, Elizabeth; Gopalakrishnan, Vidya; Somasagara, Ranganatha R.; Choudhary, Bibha; Raghavan, Sathees C.

    2016-01-01

    Medicinal plants are considered as one of the ideal sources for cancer therapy due to their bioactive contents and low toxicity to humans. Vernonia genus is one of the common medicinal plants, which has wide spread usage in food and medicine. However, there are limited studies to explore its anticancer properties. In the current study, we have used Vernonia condensata, to explore its anticancer activity using various approaches. Here, we show that extract prepared from Vernonia condensata (VCE) exhibits cytotoxic properties against various cancer cells in a dose- and time-dependent manner. Interestingly, when treated with VCE, there was no significant cytotoxicity in peripheral blood mononuclear cells (PBMCs). Flow cytometry analysis revealed that although VCE induced cell death, arrest was not observed. VCE treatment led to disruption of mitochondrial membrane potential in a concentration dependent manner resulting in activation of apoptosis culminating in cell death. Immunoblotting studies revealed that VCE activated intrinsic pathway of apoptosis. More importantly, VCE treatment resulted in tumor regression leading to significant enhancement in life span in treated mice, without showing any detectable side effects. Therefore, for the first time our study reveals the potential of extract from Vernonia condensata to be used as an anticancer agent. PMID:27009490

  5. Solanum Incanum Extract Downregulates Aldehyde Dehydrogenase 1-Mediated Stemness and Inhibits Tumor Formation in Ovarian Cancer Cells

    PubMed Central

    Wu, Yi-Hui; Chiu, Wen-Tai; Young, Ming-Jer; Chang, Tzu-Hao; Huang, Yu-Fang; Chou, Cheng-Yang

    2015-01-01

    Solanum incanum extract (SR-T100), containing the active ingredient solamargine, can induce apoptosis via upregulation of tumor necrosis factor receptor expression and activation of the mitochondrial apoptosis pathway, and has therapeutic effects in patients with actinic keratosis. Here, we evaluate the novel molecular mechanisms underlying SR-T100-regulated stemness and chemoresistance. The concentration of SR-T100 that inhibited 50% cell viability (IC50) was lower in ovarian cancer cells than in nonmalignant cells. Furthermore, the SR-T100 IC50 in chemoresistant cells was similar to the IC50 in chemosensitive cells. Additionally, SR-T100 increased cisplatin and paclitaxel sensitivity in chemoresistant cells. SR-T100 downregulated the expression of stem cell markers, including aldehyde dehydrogenase 1 (ALDH1), Notch1, and FoxM1, and reduced sphere formation in ovarian cancer cells. Using microarray analyses, immunoblotting, luciferase activity, and chromatin immunoprecipitation (ChIP) assays, we showed that SR-T100 suppressed the expression of c/EBPβ and COL11A1, and its promoter activity, in resistant cells, but not sensitive cells. SR-T100, paclitaxel, and cisplatin inhibited the growth of A2780CP70 cells in mouse xenografts, as compared to the vehicle control, and the combination of cisplatin and SR-T100 was more effective than either treatment alone. SR-T100 may represent a potential therapeutic adjunct to chemotherapy for ovarian cancer treatment. PMID:26366215

  6. MDM2 Inhibition Sensitizes Prostate Cancer Cells to Androgen Ablation and Radiotherapy in a p53-Dependent Manner12

    PubMed Central

    Feng, Felix Y.; Zhang, Yu; Kothari, Vishal; Evans, Joseph R.; Jackson, William C.; Chen, Wei; Johnson, Skyler B.; Luczak, Connor; Wang, Shaomeng; Hamstra, Daniel A.

    2016-01-01

    PURPOSE: Increased murine double minute 2 (MDM2) expression, independent of p53 status, is associated with increased cancer-specific mortality for men with prostate cancer treated with radiotherapy. We assessed MI-219, a small molecule inhibitor of MDM2 with improved pharmacokinetics over nutlin-3, for sensitization of prostate cancer cells to radiotherapy and androgen deprivation therapy, a standard treatment option for men with high-risk prostate cancer. EXPERIMENTAL DESIGN: The effect of MDM2 inhibition by MI-219 was assessed in vitro and in vivo with mouse xenograft models across multiple prostate cancer cell lines containing varying p53 functional status. RESULTS: MDM2 inhibition by MI-219 resulted in dose- and time-dependent p53 activation and decreased clonogenic cell survival after radiation in a p53-dependent manner. Mechanistically, radiosensitization following inhibition of MDM2 was largely the result of p53-dependent increases in apoptosis and DNA damage as evidenced by Annexin V flow cytometry and γ-H2AX foci immunofluorescence. Similarly, treatment with MI-219 enhanced response to antiandrogen therapy via a p53-dependent increase in apoptotic cell death. Lastly, triple therapy with radiation, androgen deprivation therapy, and MI-219 decreased xenograft tumor growth compared with any single- or double-agent treatment. CONCLUSION: MDM2 inhibition with MI-219 results in p53-dependent sensitization of prostate cancer cells to radiation, antiandrogen therapy, and the combination. These findings support MDM2 small molecule inhibitor therapy as a therapy intensification strategy to improve clinical outcomes in high-risk localized prostate cancer. TRANSLATIONAL RELEVANCE: The combination of radiotherapy and androgen deprivation therapy is a standard treatment option for men with high-risk prostate cancer. Despite improvements in outcomes when androgen deprivation therapy is added to radiation, men with high-risk prostate cancer have significant risk for

  7. Retinoic acid inhibits angiogenesis and tumor growth of thyroid cancer cells.

    PubMed

    Hoffmann, Sebastian; Rockenstein, Andreas; Ramaswamy, Anette; Celik, Ilhan; Wunderlich, Anette; Lingelbach, Susanne; Hofbauer, Lorenz C; Zielke, Andreas

    2007-01-29

    The anti-proliferative effect of retinoic acid (RA) has been documented for various tumors. Some 40% of patients with advanced and poorly differentiated thyroid cancer have been shown to respond to RA with increased uptake of radioiodine. It has been suggested that these effects may be caused by redifferentiation. Presently, little is known about the effects of RA on tumor angiogenesis, a prerequisite for growth and metastatic spread. The aim of the current study was to determine, whether tumor-induced angiogenesis of thyroid cancer is affected by RA. In vitro, the effect of 0.1/10 microM 13-cis RA on tumor cell number (MTT assay) and secretion of VEGF (ELISA) was analyzed in three thyroid cancer cell lines (FTC 236, C634 and XTC), as well as in endothelial cells (HUVEC) over several passages. In vivo, tumor growth, VEGF-expression and microvessel density (VSD) of RA treated thyroid cancer cells after xenotransplantation to nude mice was evaluated by morphometric analysis. In vitro, thyroid cancer cell lines responded to RA with reduced proliferation, ranging from 26 to 34% after 2 weeks of treatment and with up to 80% reduced secretion of VEGF. In vivo, tumor volumes of animals receiving RA were reduced by 33% (FTC 236), 27% (C643) and 6% (XTC), respectively. VSD of experimental tumors was diminished in the FTC 236 (25%) and the C643 cell line (15%), and almost unchanged in XTC tumors (7%). In vivo, VEGF-expression and apoptosis were not significantly affected by RA. In vitro, proliferation of HUVEC was inhibited by conditioned medium of C643 cells pretreated with RA (0.1/10 microM), as well as by administration of RA (0.1/10 microM). This study confirms thyroid tumor cell growth to be inhibited by RA. It demonstrates a decrease of in vitro VEGF accumulation and reduction of VSD in experimental undifferentiated thyroid carcinoma, suggesting that reduced angiogenesis may be an important mechanism responsible for the therapeutic effect of RA in thyroid cancer

  8. Genetically engineered endostatin-lidamycin fusion proteins effectively inhibit tumor growth and metastasis

    PubMed Central

    2013-01-01

    Background Endostatin (ES) inhibits endothelial cell proliferation, migration, invasion, and tube formation. It also shows antiangiogenesis and antitumor activities in several animal models. Endostatin specifically targets tumor vasculature to block tumor growth. Lidamycin (LDM), which consists of an active enediyne chromophore (AE) and a non-covalently bound apo-protein (LDP), is a member of chromoprotein family of antitumor antibiotics with extremely potent cytotoxicity to cancer cells. Therefore, we reasoned that endostatin-lidamycin (ES-LDM) fusion proteins upon energizing with enediyne chromophore may obtain the combined capability targeting tumor vasculature and tumor cell by respective ES and LDM moiety. Methods In this study, we designed and obtained two new endostatin-based fusion proteins, endostatin-LDP (ES-LDP) and LDP-endostatin (LDP-ES). In vitro, the antiangiogenic effect of fusion proteins was determined by the wound healing assay and tube formation assay and the cytotoxicity of their enediyne-energized analogs was evaluated by CCK-8 assay. Tissue microarray was used to analyze the binding affinity of LDP, ES or ES-LDP with specimens of human lung tissue and lung tumor. The in vivo efficacy of the fusion proteins was evaluated with human lung carcinoma PG-BE1 xenograft and the experimental metastasis model of 4T1-luc breast cancer. Results ES-LDP and LDP-ES disrupted the formation of endothelial tube structures and inhibited endothelial cell migration. Evidently, ES-LDP accumulated in the tumor and suppressed tumor growth and metastasis. ES-LDP and ES show higher binding capability than LDP to lung carcinoma; in addition, ES-LDP and ES share similar binding capability. Furthermore, the enediyne-energized fusion protein ES-LDP-AE demonstrated significant efficacy against lung carcinoma xenograft in athymic mice. Conclusions The ES-based fusion protein therapy provides some fundamental information for further drug development. Targeting both tumor

  9. Ewing's sarcoma family tumors are sensitive to tumor necrosis factor-related apoptosis-inducing ligand and express death receptor 4 and death receptor 5.

    PubMed

    Mitsiades, N; Poulaki, V; Mitsiades, C; Tsokos, M

    2001-03-15

    In this study, we investigated the sensitivity of Ewing's sarcoma family tumors (ESFTs) of children and adolescents to the tumor necrosis factor-related apoptosis-inducing Ligand (TRAIL). TRAIL binds to death receptors (DRs) DR4, DR5, DcR1, and DcR2. Either DR4 or DR5 can induce apoptosis, whereas DcR1 and DcR2 are considered inhibitory receptors. Nine of 10 ESFT cell lines, including several that were Fas resistant, underwent apoptosis with TRAIL through activation of caspase-10, capase-8 (FLICE), caspase-3, and caspase-9. In contrast to the Fas signaling pathway, caspase-10, but not caspase-8 or the Fas-associated death domain-containing molecule, was recruited to the TRAIL receptor-associated signaling complex. We found that 9 of 10 ESFT cell lines expressed both DR4 and DR5 by Western blotting, whereas the TRAIL-resistant line expressed only DR4. However, DR4 was absent from the cell surface in the resistant and two additional lines (three of five tested lines), suggesting that it may have been nonfunctional. On the contrary, DR5 was located on the cell surface in all four sensitive lines tested, being absent only from the cell surface of the resistant line that was also DR5-negative by Western blotting. In agreement with these findings, the resistance of the line was overcome by restoration of DR5 levels by transfection. Levels of DcR1 and DcR2 or levels of the FLICE-inhibitory protein (FLIP) did not correlate with TRAIL resistance, and protein synthesis inhibition did not sensitize the TRAIL-resistant line to TRAIL. Because these data suggested that sensitivity of ESFTs to TRAIL was mainly based on the presence of DR4/DR5, we investigated the presence of these receptors in 32 ESFT tissue sections by immunohistochemistry. We found that 23 of 32 tumor tissues (72%) expressed both receptors, 8 of 32 (25%) expressed one receptor only, and 1 was negative for both. Our finding of wide expression of DR4/DR5 in ESFT in vivo, in combination with their high sensitivity

  10. Tetrandrine Inhibits Wnt/β-Catenin Signaling and Suppresses Tumor Growth of Human Colorectal CancerS⃞

    PubMed Central

    He, Bai-Cheng; Gao, Jian-Li; Zhang, Bing-Qiang; Luo, Qing; Shi, Qiong; Kim, Stephanie H.; Huang, Enyi; Gao, Yanhong; Yang, Ke; Wagner, Eric R.; Wang, Linyuan; Tang, Ni; Luo, Jinyong; Liu, Xing; Li, Mi; Bi, Yang; Shen, Jikun; Luther, Gaurav; Hu, Ning; Zhou, Qixin; Luu, Hue H.; Haydon, Rex C.; Zhao, Yingming

    2011-01-01

    As one of the most common malignancies, colon cancer is initiated by abnormal activation of the Wnt/β-catenin pathway. Although the treatment options have increased for some patients, overall progress has been modest. Thus, there is a great need to develop new treatments. We have found that bisbenzylisoquinoline alkaloid tetrandrine (TET) exhibits anticancer activity. TET is used as a calcium channel blocker to treat hypertensive and arrhythmic conditions in Chinese medicine. Here, we investigate the molecular basis underlying TET's anticancer activity. We compare TET with six chemotherapy drugs in eight cancer lines and find that TET exhibits comparable anticancer activities with camptothecin, vincristine, paclitaxel, and doxorubicin, and better than that of 5-fluorouracil (5-FU) and carboplatin. TET IC50 is ≤5 μM in most of the tested cancer lines. TET exhibits synergistic anticancer activity with 5-FU and reduces migration and invasion capabilities of HCT116 cells. Furthermore, TET induces apoptosis and inhibits xenograft tumor growth of colon cancer. TET treatment leads to a decrease in β-catenin protein level in xenograft tumors, which is confirmed by T-cell factor/lymphocyte enhancer factor and c-Myc reporter assays. It is noteworthy that HCT116 cells with allelic oncogenic β-catenin deleted are less sensitive to TET-mediated inhibition of proliferation, viability, and xenograft tumor growth. Thus, our findings strongly suggest that the anticancer effect of TET in colon cancer may be at least in part mediated by targeting β-catenin activity. Therefore, TET may be used alone or in combination as an effective anticancer agent. PMID:20978119

  11. Probing the target-specific inhibition of sensitized protein tyrosine phosphatases with biarsenical probes

    PubMed Central

    Pomorski, Adam; Adamczyk, Justyna; Bishop, Anthony C.; Krężel, Artur

    2014-01-01

    Selective control of enzyme activity is critical for elucidating the roles of specific proteins in signaling pathways. One potential means for developing truly target-specific inhibitors involves the use of protein engineering to sensitize a target enzyme to inhibition by a small molecule that does not inhibit homologous wild-type enzymes. Previously, it has been shown that protein tyrosine phosphatases (PTPs) can be sensitized to inhibition by a biarsenical probe, FlAsH-EDT2, which inhibits PTP activity by specifically binding to cysteine residues that have been introduced into catalytically important regions. In the present study, we developed an array of biarsenical probes, some newly synthesized and some previously reported, to investigate for the first time the structure-activity relationships for PTP inhibition by biarsenicals. Our data show that biarsenical probes which contain substitutions at the 2′ and 7′ positions are more effective than FlAsH-EDT2 at inhibiting sensitized PTPs. The increased potency of 2′,7′-substituted probes was observed when PTPs were assayed with both para-nitrophenylphosphate and phosphopeptide PTP substrates and at multiple probe concentrations. The data further indicate that the enhanced inhibitory properties are the result of increased binding affinity between the 2′,7′-substituted biarsenical probes and sensitized PTPs. In addition we provide previously unknown physicochemical and stability data for various biarsenical probes. PMID:25460004

  12. Small-molecule inhibition of PTPRZ reduces tumor growth in a rat model of glioblastoma

    PubMed Central

    Fujikawa, Akihiro; Nagahira, Asako; Sugawara, Hajime; Ishii, Kentaro; Imajo, Seiichi; Matsumoto, Masahito; Kuboyama, Kazuya; Suzuki, Ryoko; Tanga, Naomi; Noda, Masanori; Uchiyama, Susumu; Tomoo, Toshiyuki; Ogata, Atsuto; Masumura, Makoto; Noda, Masaharu

    2016-01-01

    Protein tyrosine phosphatase receptor-type Z (PTPRZ) is aberrantly over-expressed in glioblastoma and a causative factor for its malignancy. However, small molecules that selectively inhibit the catalytic activity of PTPRZ have not been discovered. We herein performed an in vitro screening of a chemical library, and identified SCB4380 as the first potent inhibitor for PTPRZ. The stoichiometric binding of SCB4380 to the catalytic pocket was demonstrated by biochemical and mass spectrometric analyses. We determined the crystal structure of the catalytic domain of PTPRZ, and the structural basis of the binding of SCB4380 elucidated by a molecular docking method was validated by site-directed mutagenesis studies. The intracellular delivery of SCB4380 by liposome carriers inhibited PTPRZ activity in C6 glioblastoma cells, and thereby suppressed their migration and proliferation in vitro and tumor growth in a rat allograft model. Therefore, selective inhibition of PTPRZ represents a promising approach for glioma therapy. PMID:26857455

  13. Improvement of anti-tumor activity of photodynamic therapy through inhibition of cytoprotective mechanism in tumor cells

    NASA Astrophysics Data System (ADS)

    Nowis, Dominika; Szokalska, Angelika; Makowski, Marcin; Winiarska, Magdalena; Golab, Jakub

    2009-06-01

    Photodynamic therapy (PDT) leads to oxidative damage of cellular macromolecules, including numerous proteins that undergo multiple modifications such as fragmentation, cross-linking and carbonylation that result in protein unfolding and aggregation. Several mechanisms are involved in the protective responses to PDT that include activation of transcription factors, heat shock proteins, antioxidant enzymes and antiapoptotic pathways. Identification of these cytoprotective mechanisms might result in the design of more effective combination strategies to improve the antitumor efficacy of PDT. By using various molecular biology approaches, including microarray-based technologies we have identified genes that are up-regulated following PDT. Subsequent experiments revealed that some of these gene products can become targets for the combined therapeutic regimens encompassing PDT and selective small-molecule inhibitors. These include superoxide dismutase (SOD-2), cyclooxygenase 2 (COX-2), heme oxygenase 1 (HO-1), and proteins engaged in signaling endoplasmatic reticulum (ER) stress and unfolded protein response (UPR). Since a major mechanism for elimination of carbonylated proteins is their degradation by proteasomes, we hypothesized that a combination of PDT with proteasome inhibitors might lead to accumulation of carbonylated proteins in ER, aggravated ER stress and potentiated cytotoxicity towards tumor cells. Indeed, we observed that incubation of tumor cells with three different proteasome inhibitors, including bortezomib, MG132 and PSI gave increased accumulation of carbonylated and ubiquitinated proteins in PDT-treated cells. Proteasome inhibitors effectively sensitized tumor cells to PDT-mediated cytotoxicity and augmented antitumor effects of PDT in vivo.

  14. 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. PMID:26472927

  15. Monodispersed calcium carbonate nanoparticles modulate local pH and inhibit tumor growth in vivo.

    PubMed

    Som, Avik; Raliya, Ramesh; Tian, Limei; Akers, Walter; Ippolito, Joseph E; Singamaneni, Srikanth; Biswas, Pratim; Achilefu, Samuel

    2016-07-01

    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. PMID:26745389

  16. Hydroxycamptothecin induces apoptosis and inhibits tumor growth in colon cancer by the downregulation of survivin and XIAP expression

    PubMed Central

    2013-01-01

    Background 10-Hydroxycamptothecin (10-HCPT), isolated from a Chinese tree Camptotheca acuminate, inhibits the activity of topoisomerase I and has a broad spectrum of anticancer activity in vitro and in vivo. It has been shown that HCPT is more active and less toxic than conventional camptothecins and can induce cancer cell apoptosis. However, the mechanisms of HCPT-induced apoptosis in colon cancer cells remain unclear. In this study, we investigated the effects of HCPT on apoptosis of colon cancer and underlying mechanism. Methods Cell proliferation was measured by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay, and apoptosis was measured using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. Expression of genes was detected using real-time reverse transcription-polymerase chain reaction (real time-PCR) and Western blot. Tumor growth in vivo was evaluated using a nude mouse xenograft model. Results HCPT could significantly inhibit cell proliferation and induce apoptosis in colon cancer SW1116 and Colo 205 cells in dose- and time-dependent manners. HCPT treatment activated the activities of caspase 3, 7, 8 and 9, downregulated the expression of survivin, survivinΔEx3, survivin-3B and XIAP, and upregulated expression of surviving 2B. Moreover, the combination of HCPT and 5-fluorouracial (5-FU) synergistically induced apoptosis and downregulated the expression of survivin and XIAP. Knockdown of survivin and XIAP by siRNA sensitized colon cancer to HCTP-induced apoptosis. Furthermore, HCPT treatment significantly inhibited SW1116 xenograft tumor growth. Conclusions Our results elucidate new mechanisms of HCPT antitumor by the downregulation of survivin and XIAP expression. The combination of HCPT with 5-FU or IAP inhibitors may be a potential strategy for colon cancer treatment. PMID:23721525

  17. Altiratinib Inhibits Tumor Growth, Invasion, Angiogenesis, and Microenvironment-Mediated Drug Resistance via Balanced Inhibition of MET, TIE2, and VEGFR2.

    PubMed

    Smith, Bryan D; Kaufman, Michael D; Leary, Cynthia B; Turner, Benjamin A; Wise, Scott C; Ahn, Yu Mi; Booth, R John; Caldwell, Timothy M; Ensinger, Carol L; Hood, Molly M; Lu, Wei-Ping; Patt, Tristan W; Patt, William C; Rutkoski, Thomas J; Samarakoon, Thiwanka; Telikepalli, Hanumaiah; Vogeti, Lakshminarayana; Vogeti, Subha; Yates, Karen M; Chun, Lawrence; Stewart, Lance J; Clare, Michael; Flynn, Daniel L

    2015-09-01

    Altiratinib (DCC-2701) was designed based on the rationale of engineering a single therapeutic agent able to address multiple hallmarks of cancer (1). Specifically, altiratinib inhibits not only mechanisms of tumor initiation and progression, but also drug resistance mechanisms in the tumor and microenvironment through balanced inhibition of MET, TIE2 (TEK), and VEGFR2 (KDR) kinases. This profile was achieved by optimizing binding into the switch control pocket of all three kinases, inducing type II inactive conformations. Altiratinib durably inhibits MET, both wild-type and mutated forms, in vitro and in vivo. Through its balanced inhibitory potency versus MET, TIE2, and VEGFR2, altiratinib provides an agent that inhibits three major evasive (re)vascularization and resistance pathways (HGF, ANG, and VEGF) and blocks tumor invasion and metastasis. Altiratinib exhibits properties amenable to oral administration and exhibits substantial blood-brain barrier penetration, an attribute of significance for eventual treatment of brain cancers and brain metastases. PMID:26285778

  18. Blocking SDF-1α/CXCR4 downregulates PDGF-B and inhibits bone marrow-derived pericyte differentiation and tumor vascular expansion in Ewing tumors.

    PubMed

    Hamdan, Randala; Zhou, Zhichao; Kleinerman, Eugenie S

    2014-02-01

    Bone marrow cells (BMC) are critical to the expansion of the tumor vessel network that supports Ewing sarcoma growth. BMCs migrate to the tumor and differentiate into endothelial cells and pericytes. We recently demonstrated that stromal-derived growth factor 1α (SDF-1α) regulates platelet-derived growth factor B (PDGF-B) and that this pathway plays a critical role in bone marrow-derived pericyte differentiation in vitro. We investigated the role of SDF-1α/PDGF-B in the tumor microenvironment in vivo in promoting bone marrow-derived pericyte differentiation in Ewing tumors. The CXCR4 antagonist AMD 3100 was used to disrupt the SDF-1α/CXCR4 axis in vivo in two xenograft Ewing tumor models. BMCs from GFP(+) transgenic mice were transplanted into lethally irradiated nude mice to track BMC migration to the tumor site. Following BMC engraftment, tumor-bearing mice received daily subcutaneous injections of either PBS or AMD 3100 for 3 weeks. Tumors were resected and tumor sections were analyzed by immunohistochemistry. AMD 3100 inhibited BMC differentiation into desmin(+) and NG2(+) pericytes, affected the morphology of the tumor vasculature, decreased perfusion, and increased tumor cell apoptosis. We observed smaller vessels with tiny lumens and a decrease in the microvessel density. AMD 3100 also inhibited PDGF-B protein expression in vitro and in vivo. SDF-1α in the tumor microenvironment plays a critical role in promoting pericyte formation and Ewing sarcoma tumor neovascularization by regulating PDGF-B expression. Interfering with this pathway affects tumor vascular morphology and expansion. PMID:24282276

  19. Significantly enhanced tumor cellular and lysosomal hydroxychloroquine delivery by smart liposomes for optimal autophagy inhibition and improved antitumor efficiency with liposomal doxorubicin.

    PubMed

    Wang, Yang; Shi, Kairong; Zhang, Li; Hu, Guanlian; Wan, Jingyu; Tang, Jiajing; Yin, Sheng; Duan, Jiandong; Qin, Ming; Wang, Neng; Xie, Dandan; Gao, Xinle; Gao, Huile; Zhang, Zhirong; He, Qin

    2016-06-01

    Hydroxychloroquine (HCQ) inhibits autophagy and therefore can sensitize some cancer cells to chemotherapy, but the high doses required limit its clinical use. Here we show that loading HCQ into liposomes (HCQ/Lip) decorated with a pH-sensitive TH-RGD targeting peptide (HCQ/Lip-TR) can concentrate HCQ in B16F10 tumor cells and lysosomes. HCQ/Lip-TR was efficiently internalized as a result of its ability to bind ITGAV-ITGB3/integrin αvβ3 receptors highly expressed on the tumor cell surface and to undergo charge reversal from anionic at pH 7.4 to cationic at pH 6.5. Studies in vitro at pH 6.5 showed that the intracellular HCQ concentration was 35.68-fold higher, and lysosomal HCQ concentration 32.22-fold higher, after treating cultures with HCQ/Lip-TR than after treating them with free HCQ. The corresponding enhancements observed in mice bearing B16F10 tumors were 15.16-fold within tumor cells and 14.10-fold within lysosomes. HCQ/Lip-TR was associated with milder anemia and milder myosuppressive reductions in white blood cell and platelet counts than free HCQ, as well as less accumulation in the small intestine, which may reduce risk of intestinal side effects. In addition, co-delivering HCQ/Lip-TR with either free doxorubicin (DOX) or liposomal DOX improved the ability of DOX to inhibit tumor growth. Biochemical, electron microscopy and immunofluorescence experiments confirmed that HCQ/Lip-TR blocked autophagic flux in tumor cells. Our results suggest that loading HCQ into Lip-TR liposomes may increase the effective concentration of the inhibitor in tumor cells, allowing less toxic doses to be used. PMID:27123811

  20. Inhibition of BET bromodomain-dependent XIAP and FLIP expression sensitizes KRAS-mutated NSCLC to pro-apoptotic agents.

    PubMed

    Klingbeil, Olaf; Lesche, Ralf; Gelato, Kathy A; Haendler, Bernard; Lejeune, Pascale

    2016-01-01

    Non-small cell lung cancer (NSCLC) has the highest incidence of cancer-related death worldwide and a high medical need for more effective therapies. Small-molecule inhibitors of the bromodomain and extra terminal domain (BET) family such as JQ1, I-BET762 and OTX-015 are active in a wide range of different cancer types, including lung cancer. Although their activity on oncogene expression such as c-Myc has been addressed in many studies, the effects of BET inhibition on the apoptotic pathway remain largely unknown. Here we evaluated the activity of BET bromodomain inhibitors on cell cycle distribution and on components of the apoptosis response. Using a panel of 12 KRAS-mutated NSCLC models, we found that cell lines responsive to BET inhibitors underwent apoptosis and reduced their S-phase population, concomitant with downregulation of c-Myc expression. Conversely, ectopic c-Myc overexpression rescued the anti-proliferative effect of JQ1. In the H1373 xenograft model, treatment with JQ1 significantly reduced tumor growth and downregulated the expression of c-Myc. The effects of BET inhibition on the expression of 370 genes involved in apoptosis were compared in sensitive and resistant cells and we found the expression of the two key apoptosis regulators FLIP and XIAP to be highly BET dependent. Consistent with this, combination treatment of JQ1 with the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or the pro-apoptotic chemotherapeutic agent cisplatin enhanced induction of apoptosis in both BET inhibitor sensitive and resistant cells. Further we showed that combination of JQ1 with cisplatin led to significantly improved anti-tumor efficacy in A549 tumor-bearing mice. Altogether, these results show that the identification of BET-dependent genes provides guidance for the choice of drug combinations in cancer treatment. They also demonstrate that BET inhibition primes NSCLC cells for induction of apoptosis and that a combination with pro

  1. Patient-derived xenografts of triple-negative breast cancer reproduce molecular features of patient tumors and respond to mTOR inhibition

    PubMed Central

    2014-01-01

    Introduction Triple-negative breast cancer (TNBC) is aggressive and lacks targeted therapies. Phosphatidylinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathways are frequently activated in TNBC patient tumors at the genome, gene expression and protein levels, and mTOR inhibitors have been shown to inhibit growth in TNBC cell lines. We describe a panel of patient-derived xenografts representing multiple TNBC subtypes and use them to test preclinical drug efficacy of two mTOR inhibitors, sirolimus (rapamycin) and temsirolimus (CCI-779). Methods We generated a panel of seven patient-derived orthotopic xenografts from six primary TNBC tumors and one metastasis. Patient tumors and corresponding xenografts were compared by histology, immunohistochemistry, array comparative genomic hybridization (aCGH) and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) sequencing; TNBC subtypes were determined. Using a previously published logistic regression approach, we generated a rapamycin response signature from Connectivity Map gene expression data and used it to predict rapamycin sensitivity in 1,401 human breast cancers of different intrinsic subtypes, prompting in vivo testing of mTOR inhibitors and doxorubicin in our TNBC xenografts. Results Patient-derived xenografts recapitulated histology, biomarker expression and global genomic features of patient tumors. Two primary tumors had PIK3CA coding mutations, and five of six primary tumors showed flanking intron single nucleotide polymorphisms (SNPs) with conservation of sequence variations between primary tumors and xenografts, even on subsequent xenograft passages. Gene expression profiling showed that our models represent at least four of six TNBC subtypes. The rapamycin response signature predicted sensitivity for 94% of basal-like breast cancers in a large dataset. Drug testing of mTOR inhibitors in our xenografts showed 77 to 99% growth inhibition, significantly more than

  2. Picropodophyllin inhibits tumor growth of human nasopharyngeal carcinoma in a mouse model

    SciTech Connect

    Yin, Shu-Cheng; Guo, Wei; Tao, Ze-Zhang

    2013-09-13

    Highlights: •We identified that PPP inhibits IGF-1R/Akt pathway in NPC cells. •PPP dose-dependently inhibits NPC cell proliferation in vitro. •PPP suppresses tumor growth of NPC in nude mice. •PPP have little effect on microtubule assembly. -- Abstract: Insulin-like growth factor-1 receptor (IGF-1R) is a cell membrane receptor with tyrosine kinase activity and plays important roles in cell transformation, tumor growth, tumor invasion, and metastasis. Picropodophyllin (PPP) is a selective IGF-1R inhibitor and shows promising antitumor effects for several human cancers. However, its antitumor effects in nasopharyngeal carcinoma (NPC) remain unclear. The purpose of this study is to investigate the antitumor activity of PPP in NPC using in vitro cell culture and in vivo animal model. We found that PPP dose-dependently decreased the IGF-induced phosphorylation and activity of IGF-1R and consequently reduced the phosphorylation of Akt, one downstream target of IGF-1R. In addition, PPP inhibited NPC cell proliferation in vitro. The half maximal inhibitory concentration (IC50) of PPP for NPC cell line CNE-2 was ⩽1 μM at 24 h after treatment and ⩽0.5 μM at 48 h after treatment, respectively. Moreover, administration of PPP by intraperitoneal injection significantly suppressed the tumor growth of xenografted NPC in nude mice. Taken together, these results suggest targeting IGF-1R by PPP may represent a new strategy for treatment of NPCs with positive IGF-1R expression.

  3. Inhibition of Rho-Associated Kinase 1/2 Attenuates Tumor Growth in Murine Gastric Cancer.

    PubMed

    Hinsenkamp, Isabel; Schulz, Sandra; Roscher, Mareike; Suhr, Anne-Maria; Meyer, Björn; Munteanu, Bogdan; Fuchser, Jens; Schoenberg, Stefan O; Ebert, Matthias P A; Wängler, Björn; Hopf, Carsten; Burgermeister, Elke

    2016-08-01

    Gastric cancer (GC) remains a malignant disease with high mortality. Patients are frequently diagnosed in advanced stages where survival prognosis is poor. Thus, there is high medical need to find novel drug targets and treatment strategies. Recently, the comprehensive molecular characterization of GC subtypes revealed mutations in the small GTPase RHOA as a hallmark of diffuse-type GC. RHOA activates RHO-associated protein kinases (ROCK1/2) which regulate cell contractility, migration and growth and thus may play a role in cancer. However, therapeutic benefit of RHO-pathway inhibition in GC has not been shown so far. The ROCK1/2 inhibitor 1-(5-isoquinoline sulfonyl)-homopiperazine (HA-1077, fasudil) is approved for cerebrovascular bleeding in patients. We therefore investigated whether fasudil (i.p., 10 mg/kg per day, 4 times per week, 4 weeks) inhibits tumor growth in a preclinical model of GC. Fasudil evoked cell death in human GC cells and reduced the tumor size in the stomach of CEA424-SV40 TAg transgenic mice. Small animal PET/CT confirmed preclinical efficacy. Mass spectrometry imaging identified a translatable biomarker for mouse GC and suggested rapid but incomplete in situ distribution of the drug to gastric tumor tissue. RHOA expression was increased in the neoplastic murine stomach compared with normal non-malignant gastric tissue, and fasudil reduced (auto) phosphorylation of ROCK2 at THR249 in vivo and in human GC cells in vitro. In sum, our data suggest that RHO-pathway inhibition may constitute a novel strategy for treatment of GC and that enhanced distribution of future ROCK inhibitors into tumor tissue may further improve efficacy. PMID:27566106

  4. Targeting receptor for advanced glycation end products (RAGE) expression induces apoptosis and inhibits prostate tumor growth

    SciTech Connect

    Elangovan, Indira; Thirugnanam, Sivasakthivel; Chen, Aoshuang; Zheng, Guoxing; Bosland, Maarten C.; Kajdacsy-Balla, Andre; Gnanasekar, Munirathinam

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Targeting RAGE by RNAi induces apoptosis in prostate cancer cells. Black-Right-Pointing-Pointer Silencing RAGE expression abrogates rHMGB1 mediated cell proliferation. Black-Right-Pointing-Pointer Down regulation of RAGE by RNAi inhibits PSA secretion of prostate cancer cells. Black-Right-Pointing-Pointer Knock down of RAGE abrogates prostate tumor growth in vivo. Black-Right-Pointing-Pointer Disruption of RAGE expression in prostate tumor activates death receptors. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a key role in the progression of prostate cancer. However, the therapeutic potential of targeting RAGE expression in prostate cancer is not yet evaluated. Therefore in this study, we have investigated the effects of silencing the expression of RAGE by RNAi approach both in vitro and in vivo. The results of this study showed that down regulation of RAGE expression by RNAi inhibited the cell proliferation of androgen-dependent (LNCaP) and androgen-independent (DU-145) prostate cancer cells. Furthermore, targeting RAGE expression resulted in apoptotic elimination of these prostate cancer cells by activation of caspase-8 and caspase-3 death signaling. Of note, the levels of prostate specific antigen (PSA) were also reduced in LNCaP cells transfected with RAGE RNAi constructs. Importantly, the RAGE RNAi constructs when administered in nude mice bearing prostate tumors, inhibited the tumor growth by targeting the expression of RAGE, and its physiological ligand, HMGB1 and by up regulating death receptors DR4 and DR5 expression. Collectively, the results of this study for the first time show that targeting RAGE by RNAi may be a promising alternative therapeutic strategy for treating prostate cancer.

  5. Tankyrase Inhibitor Sensitizes Lung Cancer Cells to Endothelial Growth Factor Receptor (EGFR) Inhibition via Stabilizing Angiomotins and Inhibiting YAP Signaling.

    PubMed

    Wang, Hui; Lu, Bo; Castillo, Johnny; Zhang, Yue; Yang, Zinger; McAllister, Gregory; Lindeman, Alicia; Reece-Hoyes, John; Tallarico, John; Russ, Carsten; Hoffman, Greg; Xu, Wenqing; Schirle, Markus; Cong, Feng

    2016-07-15

    YAP signaling pathway plays critical roles in tissue homeostasis, and aberrant activation of YAP signaling has been implicated in cancers. To identify tractable targets of YAP pathway, we have performed a pathway-based pooled CRISPR screen and identified tankyrase and its associated E3 ligase RNF146 as positive regulators of YAP signaling. Genetic ablation or pharmacological inhibition of tankyrase prominently suppresses YAP activity and YAP target gene expression. Using a proteomic approach, we have identified angiomotin family proteins, which are known negative regulators of YAP signaling, as novel tankyrase substrates. Inhibition of tankyrase or depletion of RNF146 stabilizes angiomotins. Angiomotins physically interact with tankyrase through a highly conserved motif at their N terminus, and mutation of this motif leads to their stabilization. Tankyrase inhibitor-induced stabilization of angiomotins reduces YAP nuclear translocation and decreases downstream YAP signaling. We have further shown that knock-out of YAP sensitizes non-small cell lung cancer to EGFR inhibitor Erlotinib. Tankyrase inhibitor, but not porcupine inhibitor, which blocks Wnt secretion, enhances growth inhibitory activity of Erlotinib. This activity is mediated by YAP inhibition and not Wnt/β-catenin inhibition. Our data suggest that tankyrase inhibition could serve as a novel strategy to suppress YAP signaling for combinatorial targeted therapy. PMID:27231341

  6. Cool-1-mediated inhibition of c-Cbl modulates multiple critical properties of glioblastomas, including the ability to generate tumors in vivo.

    PubMed

    Stevens, Brett M; Folts, Christopher J; Cui, Wanchang; Bardin, Addie L; Walter, Kevin; Carson-Walter, Eleanor; Vescovi, Angelo; Noble, Mark

    2014-05-01

    We discovered that glioblastoma (GBM) cells use Cool-1/β-pix to inhibit normal activation of the c-Cbl ubiquitin ligase via the redox/Fyn/c-Cbl pathway and that c-Cbl inhibition is critical for GBM cell function. Restoring normal c-Cbl activity by Cool-1 knockdown in vitro reduced GBM cell division, almost eliminated generation of adhesion-independent spheroids, reduced the representation of cells expressing antigens thought to identify tumor initiating cells (TICs), reduced levels of several proteins of critical importance in TIC function (such as Notch-1 and Sox2), and increased sensitivity to BCNU (carmustine) and temozolomide (TMZ). In vivo, Cool-1 knockdown greatly suppressed the ability of GBM cells to generate tumors, an outcome that was c-Cbl dependent. In contrast, Cool-1 knockdown did not reduce division or increase BCNU or TMZ sensitivity in primary glial progenitor cells and Cool-1/c-Cbl complexes were not found in normal brain tissue. Our studies provide the first evidence that Cool-1 may be critical in the biology of human tumors, that suppression of c-Cbl by Cool-1 may be critical for generation of at least a subset of GBMs and offer a novel target that appears to be selectively necessary for TIC function and modulates chemoresistance in GBM cells. Targeting such proteins that inhibit c-Cbl offers potentially attractive opportunities for therapeutic development. PMID:24458840

  7. Inhibition of histamine receptor 3 suppresses glioblastoma tumor growth, invasion, and epithelial-to-mesenchymal transition.

    PubMed

    Lin, Jia-Ji; Zhao, Tian-Zhi; Cai, Wen-Ke; Yang, Yong-Xiang; Sun, Chao; Zhang, Zhuo; Xu, Yu-Qiao; Chang, Ting; Li, Zhu-Yi

    2015-07-10

    Histamine receptor 3 (H3R) is expressed in various tumors and correlated with malignancy and tumor proliferation. However, the role of H3R in tumor invasion and epithelial to mesenchymal transition (EMT) remains unknown. Here, we explored the H3R in the highly invasive glioblastoma (GBM) and U87MG cells. We found that H3R mRNA and protein levels were up-regulated in the GBM and glioma cell lines compared to normal brain tissue and astrocytes. In U87MG cell line, inhibition of H3R by siRNA or the antagonist ciproxifan (CPX) suppressed proliferation, invasiveness, and the expression of EMT activators (Snail, Slug and Twist). In addition, expression of epithelial markers (E-cadherin and ZO-1) was up-regulated and expression of mesenchymal markers (vimentin and N-cadherin) was down-regulated in vitro and in vivo in a xenograft model. In addition, we also showed that inhibition of H3R by siRNA or CPX inactivated the PI3K/Akt and MEK/ERK signaling pathways, while inhibition of Akt or ERK activity with antagonists or siRNAs suppressed H3R agonist (R)-(α)-(-)- methylhistamine dihydrobromide (RAMH) mediated invasion and reorganization of cadherin-household. In conclusion, overexpression of H3R is associated with glioma progression. Inhibition of H3R leads to suppressed invasion and EMT of GBM by inactivating the PI3K/Akt and MEK/ERK pathways in gliomas. PMID:25940798

  8. The ubiquitin E3 ligase ITCH enhances breast tumor progression by inhibiting the Hippo tumor suppressor pathway

    PubMed Central

    Salah, Zaidoun; Itzhaki, Ella; Aqeilan, Rami I

    2014-01-01

    The Hippo kinase pathway is emerging as a conserved signaling pathway that is essential for organ growth and tumorigenesis. Recently, we reported that the ubiquitin E3 ligase ITCH negatively regulates LATS1, thereby increasing YAP activity, which leads to increased cell proliferation and decreased apoptosis. Here, we investigated the role of ITCH in breast tumorigenesis. In particular, we show that ITCH enhances epithelial-to-mesenchymal transition (EMT) through boosting YAP oncogenic function. By contrast, a point mutation in the catalytic domain or WW1 domain of ITCH abolished its EMT-mediated effects. Furthermore, while overexpression of ITCH expression in breast cells is associated with increased incidence of mammary tumor formation and progression, its knockdown inhibited breast cancer cell tumorigenicity and metastasis. Importantly, YAP knockdown was able to attenuate ITCH pro-tumorigenic functions. Lastly, we found that ITCH expression is significantly upregulated in invasive and metastatic breast cancer cases and is associated with worse survival. Together, our results reveal that ITCH pro-tumorigenic functions in breast cancer are mediated, at least in part, through inactivation of the Hippo tumor suppressor pathway. PMID:25350971

  9. Inhibition of PKM2 sensitizes triple-negative breast cancer cells to doxorubicin

    SciTech Connect

    Wang, Feng; Yang, Yong

    2014-11-21

    Highlights: • Suppression of PKM2 sensitizes triple-negative breast cancer cells to doxorubicin. • Repression of PKM2 affects the glycolysis and decreases ATP production. • Downregulation of PKM2 increases the intracellular accumulation of doxorubicin. • Inhibition of PKM2 enhances the antitumor efficacy of doxorubicin in vivo. - Abstract: Cancer cells alter regular metabolic pathways in order to sustain rapid proliferation. One example of metabolic remodeling in cancerous tissue is the upregulation of pyruvate kinase isoenzyme M2 (PKM2), which is involved in aerobic glycolysis. Indeed, PKM2 has previously been identified as a tumor biomarker and as a potential target for cancer therapy. Here, we examined the effects of combined treatment with doxorubicin and anti-PKM2 small interfering RNA (siRNA) on triple-negative breast cancer (TNBC). The suppression of PKM2 resulted in changes in glucose metabolism, leading to decreased synthesis of adenosine triphosphate (ATP). Reduced levels of ATP resulted in the intracellular accumulation of doxorubicin, consequently enhancing the therapeutic efficacy of this drug in several triple-negative breast cancer cell lines. Furthermore, the combined effect of PKM2 siRNA and doxorubicin was evaluated in an in vivo MDA-MB-231 orthotopic breast cancer model. The siRNA was systemically administered through a polyethylenimine (PEI)-based delivery system that has been extensively used. We demonstrate that the combination treatment showed superior anticancer efficacy as compared to doxorubicin alone. These findings suggest that targeting PKM2 can increase the efficacy of chemotherapy, potentially providing a new approach for improving the outcome of chemotherapy in patients with TNBC.

  10. Increasing oxygenation and radiation sensitivity following photodynamic therapy with verteporfin in the RIF-1 tumor

    NASA Astrophysics Data System (ADS)

    Pogue, Brian W.; O'Hara, Julia A.; Demidenko, Eugene; Wilmot, Carmen M.; Chen, Bin; Swartz, Harold M.; Hasan, Tayyaba

    2003-06-01

    The combination of verteporfin-based photodynamic therapy (PDT) wiht radiaiton therapy from an orthovoltage device has been examiend in the radiation induced fibrosarcoma tumor model. PDT with verteporfin using a 3 hour delay between injection and the time of optical irradiation has been shown to cause a significant rise in overlal tumor oxygenation. It was huypothesized that this mechanism arises from the reduced oxygen consumption from cells where the PDT has targeted the mitochondria and shut down cellular respiration. Tumor blood flow was measured and found to be still be patent immediately following therapy. This increasing oxygenation was thought to provide an opportunity to increase the radiation sensitivity of the tumor immediately following PDT. When this type of treatment was combined with radiation therapy, a delay in the tumor regrowth time demonstrated that the combined effect was greater than additive. Further study of this phenomenon will provide a more complete mechanistic understanding of the effect and possibly provide a viable pre-treatment for radiation therapy of tumore that increases the therapeutic ratio. This effect could be used to either increase the radiaton dose without increasing the side effects or decrease the dose needed for the same effect on the tumor.

  11. Hedgehog inhibition reduces angiogenesis by downregulation of tumoral VEGF-A expression in hepatocellular carcinoma

    PubMed Central

    Pinter, Matthias; Sieghart, Wolfgang; Schmid, Monika; Dauser, Bernhard; Prager, Gerald; Dienes, Hans Peter; Trauner, Michael

    2013-01-01

    Background Dysregulation and activation of Hedgehog (Hh) signalling may contribute to tumorigenesis, angiogenesis, and metastatic seeding in several solid tumours. Objective We investigated the impact of Hh inhibition on tumour growth and angiogenesis using in-vitro and in-vivo models of hepatocellular carcinoma (HCC). Methods The effect of the Hh pathway inhibitor GDC-0449 on tumour growth was investigated using an orthotopic rat model. Effects on angiogenesis were determined by immunohistochemical staining of von Willebrand factor antigen and by assessing the mRNA expression of several angiogenic factors. In vitro, HCC cell lines were treated with GDC-0449 and evaluated for viability and expression of vascular endothelial growth factor (VEGF). Endothelial cells were evaluated for viability, migration, and tube formation. Results In the orthotopic HCC model, GDC-0449 significantly decreased tumoral VEGF expression which was accompanied by a significant reduction of microvessel density and tumour growth. In HCC cells, GDC-0449 had no effect on cell growth but significantly reduced target gene regulation and VEGF expression while having no direct effect on endothelial cell viability, migration, and tube formation. Conclusions Hh inhibition with GDC-0449 downregulates tumoral VEGF production in vitro and reduces tumoral VEGF expression, angiogenesis, and tumour growth in an orthotopic HCC model. PMID:24917971

  12. Local anesthetics inhibit kinesin motility and microtentacle protrusions in human epithelial and breast tumor cells.

    PubMed

    Yoon, Jennifer R; Whipple, Rebecca A; Balzer, Eric M; Cho, Edward H; Matrone, Michael A; Peckham, Michelle; Martin, Stuart S

    2011-10-01

    Detached breast tumor cells produce dynamic microtubule protrusions that promote reattachment of cells and are termed tubulin microtentacles (McTNs) due to their mechanistic distinctions from actin-based filopodia/invadopodia and tubulin-based cilia. McTNs are enriched with vimentin and detyrosinated α-tubulin, (Glu-tubulin). Evidence suggests that vimentin and Glu-tubulin are cross-linked by kinesin motor proteins. Using known kinesin inhibitors, Lidocaine and Tetracaine, the roles of kinesins in McTN formation and function were tested. Live-cell McTN counts, adhesion assays, immunofluorescence, and video microscopy were performed to visualize inhibitor effects on McTNs. Viability and apoptosis assays were used to confirm the non-toxicity of the inhibitors. Treatments of human non-tumorigenic mammary epithelial and breast tumor cells with Lidocaine or Tetracaine caused rapid collapse of vimentin filaments. Live-cell video microscopy demonstrated that Tetracaine reduces motility of intracellular GFP-kinesin and causes centripetal collapse of McTNs. Treatment with Tetracaine inhibited the extension of McTNs and their ability to promote tumor cell aggregation and reattachment. Lidocaine showed similar effects but to a lesser degree. Our current data support a model in which the inhibition of kinesin motor proteins by Tetracaine leads to the reductions in McTNs, and provides a novel mechanism for the ability of this anesthetic to decrease metastatic progression. PMID:21069453

  13. Oridonin inhibits tumor growth in glioma by inducing cell cycle arrest and apoptosis.

    PubMed

    Zhang, X-H; Liu, Y-X; Jia, M; Han, J-S; Zhao, M; Ji, S-P; Li, A-M

    2014-01-01

    Glioma is the most common malignant intracranial tumors. Despite newly developed therapies, these treatments mainly target oncogenic signals, and unfortunately, fail to provide enough survival benefit in both human patients and mouse xenograft models, especially the first-generation therapies. Oridonin is purified from the Chinese herb Rabdosia rubescens and considered to exert extensive anti-cancer effects on human tumorigenesis. In this study, we systemically investigated the role of Oridonin in tumor growth and the underlying mechanisms in human glioma. We found that Oridonin inhibited cell proliferations in a dose- and time-dependent manner in both glioma U87 and U251 cells. Moreover, these anti-cancer effects were also confirmed in a mouse model bearing glioma. Furthermore, cell cycle arrest in S phase was observed in Oridonin-mediated growth inhibition by flow cytometry. Cell cycle arrest in S phase led to eventual cell apoptosis, as revealed by Hoechst 33342 staining and annexin V/PI double-staining. The cell apoptosis might be accomplished through a mitochondrial manner. In all, we were the first to our knowledge to report that Oridonin could exert anti-cancer effects on tumor growth in human glioma by inducing cell cycle arrest and eventual cell apoptosis. The identification of Oridonin as a critical mediator of glioma growth may potentiate Oridonin as a novel therapeutic strategies in glioma treatments. PMID:25553351

  14. Suppression of KSHV-induced angiopoietin-2 inhibits angiogenesis, infiltration of inflammatory cells, and tumor growth.

    PubMed

    Yu, Xiaolan; Sha, Jingfeng; Xiang, Shao; Qin, Sanhai; Conrad, Patricia; Ghosh, Santosh K; Weinberg, Aaron; Ye, Fengchun

    2016-08-01

    Kaposi's sarcoma (KS) is a highly angiogenic and inflammatory neoplasia. The angiogenic and inflammatory cytokine angiopoietin-2 (Ang-2) is strongly expressed in KS due to Kaposi's sarcoma-associated herpesvirus (KSHV) infection. In the present study, we determined how Ang-2 contributes to development of KS by using telomerase-immortalized human umbilical vein endothelial cells (TIVE) as a model, which become malignantly transformed and express increased levels of Ang-2 following KSHV infection. Ang-2 released from TIVE-KSHV cells induces tyrosine phosphorylation of Tie-2 receptor from both human and mouse endothelial cells and promotes angiogenesis in nude mice. Functional inhibition or expressional "knock-down" of Ang-2 in these cells blocks angiogenesis and inhibits tumor growth. Ang-2 suppression also reduces the numbers of infiltrating monocytes/macrophages in tumors. In transwell-based cell migration assays, Ang-2 indeed enhances migration of human monocytes in a dose-dependent manner. These results underscore a pivotal role of KSHV-induced Ang-2 in KS tumor development by promoting both angiogenesis and inflammation. Our data also suggest that selective drug targeting of Ang-2 may be used for treatment of KS. PMID:27294705

  15. FBXW7 acts as an independent prognostic marker and inhibits tumor growth in human osteosarcoma.

    PubMed

    Li, Zhanchun; Xiao, Jie; Hu, Kongzu; Wang, Gang; Li, Maoqiang; Zhang, Jidong; Cheng, Guangqi

    2015-01-01

    F-box and WD repeat domain-containing 7 (FBXW7) is a potent tumor suppressor in human cancers including breast cancer, colorectal cancer, gastric cancer and hepatocellular carcinoma. In this study, we found that the expressions of FBXW7 protein and mRNA levels in osteosarcoma (OS) cases were significantly lower than those in normal bone tissues. Clinical analysis indicated that FBXW7 was expressed at lower levels in OS patients with advanced clinical stage, high T classification and poor histological differentiation. Furthermore, we demonstrated that high expression of FBXW7 was correlated with a better 5-year survival of OS patients. Multivariate Cox regression analysis indicated that FBXW7 was an independent prognostic marker in OS. Our in vitro studies showed that FBXW7 overexpression inhibited cell cycle transition and cell proliferation, and promoted apoptosis in both U2OS and MG-63 cells. In a nude mouse xenograft model, FBXW7 overexpression slowed down tumor growth by inducing apoptosis and growth arrest. Mechanistically, FBXW7 inversely regulated oncoprotein c-Myc and cyclin E levels in both U2OS and MG-63 cells. Together these findings suggest that FBXW7 may serve as a prognostic biomarker and inhibit tumor progression by inducing apoptosis and growth arrest in OS. PMID:25622249

  16. Anti-tumor activity of benzylideneacetophenone derivatives via proteasomal inhibition in prostate cancer cells.

    PubMed

    Lee, Yun-hee; Yun, Jaesuk; Jung, Jae-Chul; Oh, Seikwan; Jung, Young-Suk

    2016-05-01

    A number of some chalcone derivatives possess promising biological properties including anti-inflammation, anti-oxidant, and anti-tumor activity. Although it has been shown that some derivatives of chalcone induce apoptosis in different kinds of cancer cells, the involved mechanism of action is not well defined. The purpose of this study is to investigate the primary target of a benzylideneacetophenone derivative (JC3), which is a synthetic compound derived from the chalcone family, in human cancer, using prostate cancer cells as a working model. Herein, we show that JC3 inhibits proteasomal activity as indicated by both in vitro and in cell-based assays. Especially, the JC3-dimer was more potent than monomer in the aspect of proteasome inhibition, which induced apoptosis significantly in the prostate cancer cells. Owing to the critical roles of the proteasome in the biology of human tumor progression, invasion, and metastasis, these findings give an important clue for the development of novel anti-tumor agents. PMID:27348972

  17. Metformin prevents cancer metastasis by inhibiting M2-like polarization of tumor associated macrophages

    PubMed Central

    Ding, Ling; Liang, Guikai; Yao, Zhangting; Zhang, Jieqiong; Liu, Ruiyang; Chen, Huihui; Zhou, Yulu; Wu, Honghai; Yang, Bo; He, Qiaojun

    2015-01-01

    Accumulated evidence suggests that M2-like polarized tumor associated macrophages (TAMs) plays an important role in cancer progression and metastasis, establishing TAMs, especially M2-like TAMs as an appealing target for therapy intervention. Here we found that metformin significantly suppressed IL-13 induced M2-like polarization of macrophages, as illustrated by reduced expression of CD206, down-regulation of M2 marker mRNAs, and inhibition of M2-like macrophages promoted migration of cancer cells and endothelial cells. Metformin triggered AMPKα1 activation in macrophage and silencing of AMPKα1 partially abrogated the inhibitory effect of metformin in IL-13 induced M2-like polarization. Administration of AICAR, another activator of AMPK, also blocked the M2-like polarization of macrophages. Metformin greatly reduced the number of metastases of Lewis lung cancer without affecting tumor growth. In tumor tissues, the percentage of M2-like macrophage was decreased and the area of pericyte-coated vessels was increased. Further, the anti-metastatic effect of metformin was abolished when the animals were treated with macrophages eliminating agent clodronate liposome. These findings suggest that metformin is able to block the M2-like polarization of macrophages partially through AMPKα1, which plays an important role in metformin inhibited metastasis of Lewis lung cancer. PMID:26497364

  18. Oncogenic Mutation of AIMP2/p38 Inhibits Its Tumor-Suppressive Interaction with Smurf2.

    PubMed

    Kim, Dae Gyu; Lee, Jin Young; Lee, Ji-Hyun; Cho, Ha Yeon; Kang, Beom Sik; Jang, Song-Yee; Kim, Myung Hee; Guo, Min; Han, Jung Min; Kim, Seong-Jin; Kim, Sunghoon

    2016-06-01

    AIMP2/p38 is a multifunctional tumor suppressor that normally resides in the cytosol as a scaffold protein of the multi-tRNA synthetase complex (MSC). One of the tumor-suppressive functions of AIMP2 is to facilitate ubiquitin-mediated degradation of FUSE-binding protein (FBP, FUBP1), a transcriptional activator of c-Myc. However, the mechanism by which AIMP2 functions within this pathway and its significance in tumorigenesis are uncertain. Here, we report that Smurf2 is responsible for AIMP2-mediated ubiquitination of FBP, and a mutation in AIMP2 that inhibited its nuclear interaction with Smurf2 enhanced cellular transformation and tumorigenesis in vivo Treatment of HeLa cells with TGFβ resulted in the phosphorylation of AIMP2 on S156, a residue that is exposed on the embedded GST domain of AIMP2. We further found that phospho-AIMP2 dissociated from the MSC and translocated to the nucleus, where it bound to Smurf2, enhancing ubiquitination of FBP. AIMP2 also inhibited nuclear export of Smurf2 to sustain TGFβ signaling. Collectively, these findings present a novel tumor-suppressive interaction between AIMP2 and Smurf2 and suggest that the disruption of this interaction can lead to oncogenic transformation. Cancer Res; 76(11); 3422-36. ©2016 AACR. PMID:27197155

  19. Targeted BMI1 inhibition impairs tumor growth in lung adenocarcinomas with low CEBPα expression.

    PubMed

    Yong, Kol Jia; Basseres, Daniela S; Welner, Robert S; Zhang, Wen Cai; Yang, Henry; Yan, Benedict; Alberich-Jorda, Meritxell; Zhang, Junyan; de Figueiredo-Pontes, Lorena Lobo; Battelli, Chiara; Hetherington, Christopher J; Ye, Min; Zhang, Hong; Maroni, Giorgia; O'Brien, Karen; Magli, Maria Cristina; Borczuk, Alain C; Varticovski, Lyuba; Kocher, Olivier; Zhang, Pu; Moon, Young-Choon; Sydorenko, Nadiya; Cao, Liangxian; Davis, Thomas W; Thakkar, Bhavin M; Soo, Ross A; Iwama, Atsushi; Lim, Bing; Halmos, Balazs; Neuberg, Donna; Tenen, Daniel G; Levantini, Elena

    2016-08-01

    Lung cancer is the most common cause of cancer deaths. The expression of the transcription factor C/EBPα (CCAAT/enhancer binding protein α) is frequently lost in non-small cell lung cancer, but the mechanisms by which C/EBPα suppresses tumor formation are not fully understood. In addition, no pharmacological therapy is available to specifically target C/EBPα expression. We discovered a subset of pulmonary adenocarcinoma patients in whom negative/low C/EBPα expression and positive expression of the oncogenic protein BMI1 (B lymphoma Mo-MLV insertion region 1 homolog) have prognostic value. We also generated a lung-specific mouse model of C/EBPα deletion that develops lung adenocarcinomas, which are prevented by Bmi1 haploinsufficiency. BMI1 activity is required for both tumor initiation and maintenance in the C/EBPα-null background, and pharmacological inhibition of BMI1 exhibits antitumor effects in both murine and human adenocarcinoma lines. Overall, we show that C/EBPα is a tumor suppressor in lung cancer and that BMI1 is required for the oncogenic process downstream of C/EBPα loss. Therefore, anti-BMI1 pharmacological inhibition may offer a therapeutic benefit for lung cancer patients with low expression of C/EBPα and high BMI1. PMID:27488898

  20. BRAF Inhibition Generates a Host-Tumor Niche that Mediates Therapeutic Escape.

    PubMed

    Fedorenko, Inna V; Wargo, Jennifer A; Flaherty, Keith T; Messina, Jane L; Smalley, Keiran S M

    2015-12-01

    The current study defines a fibroblast-derived niche that facilitates the therapeutic escape of melanoma cells from BRAF inhibition. Vemurafenib treatment led to the release of transforming growth factor-β (TGF-β) from the melanoma cells that increased the differentiation state of the fibroblasts, an affect associated with fibronectin deposition, increase in α-smooth muscle actin expression, and the release of neuregulin (NRG). At the same time, vemurafenib directly activated the fibroblasts through paradoxical stimulation of the mitogen-activated protein kinase pathway, causing them to secrete hepatocyte growth factor (HGF). Treatment with the BRAF/MEK inhibitor combination reversed the release of HGF. Adhesion of melanoma cells to fibronectin was critical in amplifying the fibroblast-derived NRG- and HGF-mediated PI3K/AKT (phosphatidylinositol 3'-kinase/AKT) survival signaling in the melanoma cells following BRAF inhibition. In coculture studies, combination treatment with inhibitors of BRAF/MET/HER kinase was ineffective at reversing the fibroblast-mediated therapeutic escape from BRAF inhibition. Instead, it was noted that combined BRAF/PI3K inhibition overcame fibroblast-mediated drug resistance in vitro and was associated with enhanced antitumor effects in an in vivo xenograft model. Thus, we show that melanoma cells and fibroblasts remodel their microenvironment in response to BRAF inhibition and that these adaptations allow tumor cells to evade therapy through increased PI3K/AKT survival signaling. PMID:26302068

  1. Syzygium campanulatum korth methanolic extract inhibits angiogenesis and tumor growth in nude mice

    PubMed Central

    2013-01-01

    Background Syzygium campanulatum Korth (Myrtaceae) is an evergreen shrub rich in phenolics, flavonoid antioxidants, and betulinic acid. This study sought to investigate antiangiogenic and anti-colon cancer effects of S.C. standardized methanolic extract. Methods Betulinic acid was isolated from methanolic extract by crystallization and chromatography techniques. S.C. methanolic extract was analyzed by UV-Vis spectrophotometry, FTIR, LC-MS, and HPLC. Antiangiogenic effect was studied on rat aortic rings, matrigel tube formation, cell proliferation and migration, and expression of vascular endothelial growth factor (VEGF). Antitumor effect was studied using a subcutaneous tumor model of HCT 116 colorectal carcinoma cells established in nude mice. Results Analysis by HPLC, LC-MS and FTIR confirm presence of betulinic acid in S.C. methanolic extract. Quantitative analysis by HPLC indicates presence of betulinic acid in S.C. extract at 5.42 ± 0.09% (w/w). Antiangiogenesis study showed potent inhibition of microvessels outgrowth in rat aortic rings, and studies on normal and cancer cells did not show any significant cytotoxic effect. Antiangiogenic effect was further confirmed by inhibition of tube formation on matrigel matrix that involves human endothelial cells (IC50 = 17.6 ± 2.9 μg/ml). S.C. extract also inhibited migration of endothelial cells and suppressed expression of VEGF. In vivo antiangiogenic study showed inhibition of new blood vessels in chicken embryo chorioallantoic membrane (CAM), and in vivo antitumor study showed significant inhibition of tumor growth due to reduction of intratumor blood vessels and induction of cell death. Conclusion Collectively, our results indicate S. campanulatum as antiangiogenic and antitumor candidate, and a new source of betulinic acid. PMID:23842450

  2. Structural and Enzymatic Analysis of Tumor-Targeted Antifolates That Inhibit Glycinamide Ribonucleotide Formyltransferase.

    PubMed

    Deis, Siobhan M; Doshi, Arpit; Hou, Zhanjun; Matherly, Larry H; Gangjee, Aleem; Dann, Charles E

    2016-08-16

    Pemetrexed and methotrexate are antifolates used for cancer chemotherapy and inflammatory diseases. These agents have toxic side effects resulting, in part, from nonspecific cellular transport by the reduced folate carrier (RFC), a ubiquitously expressed facilitative transporter. We previously described 2-amino-4-oxo-6-substituted pyrrolo[2,3-d]pyrimidine antifolates with modifications of the side chain linker and aromatic ring that are poor substrates for RFC but are efficiently transported via folate receptors (FRs) and the proton-coupled folate transporter (PCFT). These targeted antifolates are cytotoxic in vitro toward FR- and PCFT-expressing tumor cells and in vivo with human tumor xenografts in immune-compromised mice, reflecting selective cellular uptake. Antitumor efficacy is due to inhibition of glycinamide ribonucleotide (GAR) formyltransferase (GARFTase) activity in de novo synthesis of purine nucleotides. This study used purified human GARFTase (formyltransferase domain) to assess in vitro inhibition by eight novel thieno- and pyrrolo[2,3-d]pyrimidine antifolates. Seven analogues (AGF23, AGF71, AGF94, AGF117, AGF118, AGF145, and AGF147) inhibited GARFTase with Ki values in the low- to mid-nanomolar concentration range, whereas AGF50 inhibited GARFTase with micromolar potency similar to that of PMX. On the basis of crystal structures of ternary complexes with GARFTase, β-GAR, and the monoglutamyl antifolates, differences in inhibitory potencies correlated well with antifolate binding and the positions of the terminal carboxylates. Our data provide a mechanistic basis for differences in inhibitory potencies between these novel antifolates and a framework for future structure-based drug design. These analogues could be more efficacious than clinically used antifolates, reflecting their selective cellular uptake by FRs and PCFT and potent GARFTase inhibition. PMID:27439469

  3. PPARα inhibition modulates multiple reprogrammed metabolic pathways in kidney cancer and attenuates tumor growth

    PubMed Central

    Abu Aboud, Omran; Donohoe, Dallas; Bultman, Scott; Fitch, Mark; Riiff, Tim; Hellerstein, Marc

    2015-01-01

    Kidney cancer [renal cell carcinoma (RCC)] is the sixth-most-common cancer in the United States, and its incidence is increasing. The current progression-free survival for patients with advanced RCC rarely extends beyond 1–2 yr due to the development of therapeutic resistance. We previously identified peroxisome proliferator-activating receptor-α (PPARα) as a potential therapeutic target for this disease and showed that a specific PPARα antagonist, GW6471, induced apoptosis and cell cycle arrest at G0/G1 in RCC cell lines associated with attenuation of cell cycle regulatory proteins. We now extend that work and show that PPARα inhibition attenuates components of RCC metabolic reprogramming, capitalizing on the Warburg effect. The specific PPARα inhibitor GW6471, as well as a siRNA specific to PPARα, attenuates the enhanced fatty acid oxidation and oxidative phosphorylation associated with glycolysis inhibition, and PPARα antagonism also blocks the enhanced glycolysis that has been observed in RCC cells; this effect did not occur in normal human kidney epithelial cells. Such cell type-specific inhibition of glycolysis corresponds with changes in protein levels of the oncogene c-Myc and has promising clinical implications. Furthermore, we show that treatment with GW6471 results in RCC tumor growth attenuation in a xenograft mouse model, with minimal obvious toxicity, a finding associated with the expected on-target effects on c-Myc. These studies demonstrate that several pivotal cancer-relevant metabolic pathways are inhibited by PPARα antagonism. Our data support the concept that targeting PPARα, with or without concurrent inhibition of glycolysis, is a potential novel and effective therapeutic approach for RCC that targets metabolic reprogramming in this tumor. PMID:25810260

  4. Formononetin sensitizes glioma cells to doxorubicin through preventing EMT via inhibition of histone deacetylase 5.

    PubMed

    Liu, Quan; Sun, Yan; Zheng, Jie-Min; Yan, Xian-Lei; Chen, Hong-Mou; Chen, Jia-Kang; Huang, He-Qing

    2015-01-01

    Chemoresistance is a major obstacle to successful chemotherapy for glioma. Formononetin is a novel herbal isoflavonoid isolated from Astragalus membranaceus and possesses antitumorigenic properties. In the present study, we investigated the anti-proliferative effects of formononetin on human glioma cells, and further elucidated the molecular mechanism underlying the anti-tumor property. We found that formononetin enhanced doxorubicin cytotoxicity in glioma cells. Combined treatment with formononetin reversed the doxorubicin-induced epithelial-mesenchymal transition (EMT) in tumor cells. Moreover, we found that formononetin treatment significantly decreased the expression of HDAC5. Overexpression of HDAC5 diminished the suppressive effects of formononetin on glioma cell viability. Furthermore, knockdown of HDAC5 by siRNA inhibited the doxorubicin-induced EMT in glioma cells. Taken together, these results demonstrated that formononetin-combined therapy may enhance the therapeutic efficacy of doxorubicin in glioma cells by preventing EMT through inhibition of HDAC5. PMID:26261519

  5. Formononetin sensitizes glioma cells to doxorubicin through preventing EMT via inhibition of histone deacetylase 5

    PubMed Central

    Liu, Quan; Sun, Yan; Zheng, Jie-Min; Yan, Xian-Lei; Chen, Hong-Mou; Chen, Jia-Kang; Huang, He-Qing

    2015-01-01

    Chemoresistance is a major obstacle to successful chemotherapy for glioma. Formononetin is a novel herbal isoflavonoid isolated from Astragalus membranaceus and possesses antitumorigenic properties. In the present study, we investigated the anti-proliferative effects of formononetin on human glioma cells, and further elucidated the molecular mechanism underlying the anti-tumor property. We found that formononetin enhanced doxorubicin cytotoxicity in glioma cells. Combined treatment with formononetin reversed the doxorubicin-induced epithelial-mesenchymal transition (EMT) in tumor cells. Moreover, we found that formononetin treatment significantly decreased the expression of HDAC5. Overexpression of HDAC5 diminished the suppressive effects of formononetin on glioma cell viability. Furthermore, knockdown of HDAC5 by siRNA inhibited the doxorubicin-induced EMT in glioma cells. Taken together, these results demonstrated that formononetin-combined therapy may enhance the therapeutic efficacy of doxorubicin in glioma cells by preventing EMT through inhibition of HDAC5. PMID:26261519

  6. Paracrine expression of a native soluble vascular endothelial growth factor receptor inhibits tumor growth, metastasis, and mortality rate

    PubMed Central

    Goldman, Corey K.; Kendall, Richard L.; Cabrera, Gustavo; Soroceanu, Liliana; Heike, Yuji; Gillespie, G. Yancey; Siegal, Gene P.; Mao, Xianzhi; Bett, Andrew J.; Huckle, William R.; Thomas, Kenneth A.; Curiel, David T.

    1998-01-01

    Vascular endothelial growth factor (VEGF) is a potent and selective vascular endothelial cell mitogen and angiogenic factor. VEGF expression is elevated in a wide variety of solid tumors and is thought to support their growth by enhancing tumor neovascularization. To block VEGF-dependent angiogenesis, tumor cells were transfected with cDNA encoding the native soluble FLT-1 (sFLT-1) truncated VEGF receptor which can function both by sequestering VEGF and, in a dominant negative fashion, by forming inactive heterodimers with membrane-spanning VEGF receptors. Transient transfection of HT-1080 human fibrosarcoma cells with a gene encoding sFLT-1 significantly inhibited their implantation and growth in the lungs of nude mice following i.v. injection and their growth as nodules from cells injected s.c. High sFLT-1 expressing stably transfected HT-1080 clones grew even slower as s.c. tumors. Finally, survival was significantly prolonged in mice injected intracranially with human glioblastoma cells stably transfected with the sflt-1 gene. The ability of sFLT-1 protein to inhibit tumor growth is presumably attributable to its paracrine inhibition of tumor angiogenesis in vivo, since it did not affect tumor cell mitogenesis in vitro. These results not only support VEGF receptors as antiangiogenic targets but also demonstrate that sflt-1 gene therapy might be a feasible approach for inhibiting tumor angiogenesis and growth. PMID:9671758

  7. Shikonin Inhibits the Proliferation of Human Breast Cancer Cells by Reducing Tumor-Derived Exosomes.

    PubMed

    Wei, Yao; Li, Mingzhen; Cui, Shufang; Wang, Dong; Zhang, Chen-Yu; Zen, Ke; Li, Limin

    2016-01-01

    Shikonin is a naphthoquinone isolated from the traditional Chinese medicine Lithospermum. It has been used in the treatment of various tumors. However, the effects of shikonin on such diseases have not been fully elucidated. In the present study, we detected the exosome release of a breast cancer cell line (MCF-7) with shikonin treatment and found a positive relationship between the level of secreted exosomes and cell proliferation. We next analyzed miRNA profiles in MCF-7 cells and exosomes and found that some miRNAs are specifically sorted and abundant in exosomes. Knockdown of the most abundant miRNAs in exosomes and the MCF-7 proliferation assay showed that miR-128 in exosomes negatively regulates the level of Bax in MCF-7 recipient cells and inhibits cell proliferation. These results show that shikonin inhibits the proliferation of MCF-7 cells through reducing tumor-derived exosomal miR-128. The current study suggests that shikonin suppresses MCF-7 growth by the inhibition of exosome release. PMID:27322220

  8. Protonation and Trapping of a Small pH-Sensitive Near-Infrared Fluorescent Molecule in the Acidic Tumor Environment Delineate Diverse Tumors in Vivo.

    PubMed

    Gilson, Rebecca C; Tang, Rui; Som, Avik; Klajer, Chloe; Sarder, Pinaki; Sudlow, Gail P; Akers, Walter J; Achilefu, Samuel

    2015-12-01

    Enhanced glycolysis and poor perfusion in most solid malignant tumors create an acidic extracellular environment, which enhances tumor growth, invasion, and metastasis. Complex molecular systems have been explored for imaging and treating these tumors. Here, we report the development of a small molecule, LS662, that emits near-infrared (NIR) fluorescence upon protonation by the extracellular acidic pH environment of diverse solid tumors. Protonation of LS662 induces selective internalization into tumor cells and retention in the tumor microenvironment. Noninvasive NIR imaging demonstrates selective retention of the pH sensor in diverse tumors, and two-photon microscopy of ex vivo tumors reveals significant retention of LS662 in tumor cells and the acid tumor microenvironment. Passive and active internalization processes combine to enhance NIR fluorescence in tumors over time. The low background fluorescence allows tumors to be detected with high sensitivity, as well as dead or dying cells to be delineated from healthy cells. In addition to demonstrating the feasibility of using small molecule pH sensors to image multiple aggressive solid tumor types via a protonation-induced internalization and retention pathway, the study reveals the potential of using LS662 to monitor treatment response and tumor-targeted drug delivery. PMID:26488921

  9. Optimal Design for Informative Protocols in Xenograft Tumor Growth Inhibition Experiments in Mice.

    PubMed

    Lestini, Giulia; Mentré, France; Magni, Paolo

    2016-09-01

    Tumor growth inhibition (TGI) models are increasingly used during preclinical drug development in oncology for the in vivo evaluation of antitumor effect. Tumor sizes are measured in xenografted mice, often only during and shortly after treatment, thus preventing correct identification of some TGI model parameters. Our aims were (i) to evaluate the importance of including measurements during tumor regrowth and (ii) to investigate the proportions of mice included in each arm. For these purposes, optimal design theory based on the Fisher information matrix implemented in PFIM4.0 was applied. Published xenograft experiments, involving different drugs, schedules, and cell lines, were used to help optimize experimental settings and parameters using the Simeoni TGI model. For each experiment, a two-arm design, i.e., control versus treatment, was optimized with or without the constraint of not sampling during tumor regrowth, i.e., "short" and "long" studies, respectively. In long studies, measurements could be taken up to 6 g of tumor weight, whereas in short studies the experiment was stopped 3 days after the end of treatment. Predicted relative standard errors were smaller in long studies than in corresponding short studies. Some optimal measurement times were located in the regrowth phase, highlighting the importance of continuing the experiment after the end of treatment. In the four-arm designs, the results showed that the proportions of control and treated mice can differ. To conclude, making measurements during tumor regrowth should become a general rule for informative preclinical studies in oncology, especially when a delayed drug effect is suspected. PMID:27306546

  10. Close Interactions between Mesenchymal Stem Cells and Neuroblastoma Cell Lines Lead to Tumor Growth Inhibition

    PubMed Central

    Bianchi, Giovanna; Morandi, Fabio; Cilli, Michele; Daga, Antonio; Bocelli-Tyndall, Chiara; Gambini, Claudio

    2012-01-01

    Mesenchymal stem cells (MSCs) have attracted much interest in oncology since they exhibit marked tropism for the tumor microenvironment and support or suppress malignant cell growth depending on the tumor model tested. The aim of this study was to investigate the role of MSCs in the control of the growth of neuroblastoma (NB), which is the second most common solid tumor in children. In vivo experiments showed that systemically administered MSCs, under our experimental conditions, did not home to tumor sites and did not affect tumor growth or survival. However, MSCs injected intratumorally in an established subcutaneous NB model reduced tumor growth through inhibition of proliferation and induction of apoptosis of NB cells and prolonged the survival of hMSC-treated mice. The need for contact between MSCs and NB cells was further supported by in vitro experiments. In particular, MSCs were found to be attracted by NB cells, and to affect NB cell proliferation with different results depending on the cell line tested. Moreover, NB cells, after pre-incubation with hMSCs, acquired a more invasive behavior towards CXCL12 and the bone marrow, i.e., the primary site of NB metastases. In conclusion, this study demonstrates that functional cross-talk between MSCs and NB cell lines used in our experiments can occur only within short range interaction. Thus, this report does not support the clinical use of MSCs as vehicles for selective delivery of antitumor drugs at the NB site unless chemotherapy and/or radiotherapy create suitable local conditions for MSCs recruitment. PMID:23119082

  11. Adenovirus E2F1 Overexpression Sensitizes LNCaP and PC3 Prostate Tumor Cells to Radiation In Vivo

    SciTech Connect

    Udayakumar, Thirupandiyur S.; Stoyanova, Radka; Hachem, Paul; Ahmed, Mansoor M.; Pollack, Alan

    2011-02-01

    ectopic overexpression of E2F1 in vivo, using an adenoviral vector, significantly inhibits orthotopic p53 wild-type LNCaP tumors and subcutaneous p53-null PC3 tumors in nude mice. Furthermore, we demonstrate that E2F1 strongly sensitizes LNCaP tumors to RT. These findings suggest that E2F1 overexpression can sensitize prostate tumor cells in vivo, independent of p53 or androgen receptor status.

  12. Preclinical Evidence of Anti-Tumor Activity Induced by EZH2 Inhibition in Human Models of Synovial Sarcoma.

    PubMed

    Kawano, Satoshi; Grassian, Alexandra R; Tsuda, Masumi; Knutson, Sarah K; Warholic, Natalie M; Kuznetsov, Galina; Xu, Shanqin; Xiao, Yonghong; Pollock, Roy M; Smith, Jesse S; Kuntz, Kevin K; Ribich, Scott; Minoshima, Yukinori; Matsui, Junji; Copeland, Robert A; Tanaka, Shinya; Keilhack, Heike

    2016-01-01

    The catalytic activities of covalent and ATP-dependent chromatin remodeling are central to regulating the conformational state of chromatin and the resultant transcriptional output. The enzymes that catalyze these activities are often contained within multiprotein complexes in nature. Two such multiprotein complexes, the polycomb repressive complex 2 (PRC2) methyltransferase and the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeler have been reported to act in opposition to each other during development and homeostasis. An imbalance in their activities induced by mutations/deletions in complex members (e.g. SMARCB1) has been suggested to be a pathogenic mechanism in certain human cancers. Here we show that preclinical models of synovial sarcoma-a cancer characterized by functional SMARCB1 loss via its displacement from the SWI/SNF complex through the pathognomonic SS18-SSX fusion protein-display sensitivity to pharmacologic inhibition of EZH2, the catalytic subunit of PRC2. Treatment with tazemetostat, a clinical-stage, selective and orally bioavailable small-molecule inhibitor of EZH2 enzymatic activity reverses a subset of synovial sarcoma gene expression and results in concentration-dependent cell growth inhibition and cell death specifically in SS18-SSX fusion-positive cells in vitro. Treatment of mice bearing either a cell line or two patient-derived xenograft models of synovial sarcoma leads to dose-dependent tumor growth inhibition with correlative inhibition of trimethylation levels of the EZH2-specific substrate, lysine 27 on histone H3. These data demonstrate a dependency of SS18-SSX-positive, SMARCB1-deficient synovial sarcomas on EZH2 enzymatic activity and suggests the potential utility of EZH2-targeted drugs in these genetically defined cancers. PMID:27391784

  13. Preclinical Evidence of Anti-Tumor Activity Induced by EZH2 Inhibition in Human Models of Synovial Sarcoma

    PubMed Central

    Tsuda, Masumi; Knutson, Sarah K.; Warholic, Natalie M.; Kuznetsov, Galina; Xu, Shanqin; Xiao, Yonghong; Pollock, Roy M.; Smith, Jesse S.; Kuntz, Kevin K.; Ribich, Scott; Minoshima, Yukinori; Matsui, Junji; Copeland, Robert A.; Tanaka, Shinya; Keilhack, Heike

    2016-01-01

    The catalytic activities of covalent and ATP-dependent chromatin remodeling are central to regulating the conformational state of chromatin and the resultant transcriptional output. The enzymes that catalyze these activities are often contained within multiprotein complexes in nature. Two such multiprotein complexes, the polycomb repressive complex 2 (PRC2) methyltransferase and the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeler have been reported to act in opposition to each other during development and homeostasis. An imbalance in their activities induced by mutations/deletions in complex members (e.g. SMARCB1) has been suggested to be a pathogenic mechanism in certain human cancers. Here we show that preclinical models of synovial sarcoma—a cancer characterized by functional SMARCB1 loss via its displacement from the SWI/SNF complex through the pathognomonic SS18-SSX fusion protein—display sensitivity to pharmacologic inhibition of EZH2, the catalytic subunit of PRC2. Treatment with tazemetostat, a clinical-stage, selective and orally bioavailable small-molecule inhibitor of EZH2 enzymatic activity reverses a subset of synovial sarcoma gene expression and results in concentration-dependent cell growth inhibition and cell death specifically in SS18-SSX fusion-positive cells in vitro. Treatment of mice bearing either a cell line or two patient-derived xenograft models of synovial sarcoma leads to dose-dependent tumor growth inhibition with correlative inhibition of trimethylation levels of the EZH2-specific substrate, lysine 27 on histone H3. These data demonstrate a dependency of SS18-SSX-positive, SMARCB1-deficient synovial sarcomas on EZH2 enzymatic activity and suggests the potential utility of EZH2-targeted drugs in these genetically defined cancers. PMID:27391784

  14. Inhibition of NF-κB in Tumor Cells Exacerbates Immune Cell Activation Following Photodynamic Therapy.

    PubMed

    Broekgaarden, Mans; Kos, Milan; Jurg, Freek A; van Beek, Adriaan A; van Gulik, Thomas M; Heger, Michal

    2015-01-01

    Although photodynamic therapy (PDT) yields very good outcomes in numerous types of superficial solid cancers, some tumors respond suboptimally to PDT. Novel treatment strategies are therefore needed to enhance the efficacy in these therapy-resistant tumors. One of these strategies is to combine PDT with inhibitors of PDT-induced survival pathways. In this respect, the transcription factor nuclear factor κB (NF-κB) has been identified as a potential pharmacological target, albeit inhibition of NF-κB may concurrently dampen the subsequent anti-tumor immune response required for complete tumor eradication and abscopal effects. In contrast to these postulations, this study demonstrated that siRNA knockdown of NF-κB in murine breast carcinoma (EMT-6) cells increased survival signaling in these cells and exacerbated the inflammatory response in murine RAW 264.7 macrophages. These results suggest a pro-death and immunosuppressive role of NF-κB in PDT-treated cells that concurs with a hyperstimulated immune response in innate immune cells. PMID:26307977

  15. Inhibition of NF-κB in Tumor Cells Exacerbates Immune Cell Activation Following Photodynamic Therapy

    PubMed Central

    Broekgaarden, Mans; Kos, Milan; Jurg, Freek A.; van Beek, Adriaan A.; van Gulik, Thomas M.; Heger, Michal

    2015-01-01

    Although photodynamic therapy (PDT) yields very good outcomes in numerous types of superficial solid cancers, some tumors respond suboptimally to PDT. Novel treatment strategies are therefore needed to enhance the efficacy in these therapy-resistant tumors. One of these strategies is to combine PDT with inhibitors of PDT-induced survival pathways. In this respect, the transcription factor nuclear factor κB (NF-κB) has been identified as a potential pharmacological target, albeit inhibition of NF-κB may concurrently dampen the subsequent anti-tumor immune response required for complete tumor eradication and abscopal effects. In contrast to these postulations, this study demonstrated that siRNA knockdown of NF-κB in murine breast carcinoma (EMT-6) cells increased survival signaling in these cells and exacerbated the inflammatory response in murine RAW 264.7 macrophages. These results suggest a pro-death and immunosuppressive role of NF-κB in PDT-treated cells that concurs with a hyperstimulated immune response in innate immune cells. PMID:26307977

  16. The bradykinin B1 receptor antagonist R-954 inhibits Ehrlich tumor growth in rodents.

    PubMed

    Fernandes, Patricia Dias; Gomes, Niele de Matos; Sirois, Pierre

    2011-09-01

    The present study investigated the effects of a new bradykinin B(1) receptor antagonist, R-954, on the development of Ehrlich ascitic tumor (EAT) induced by the intraperitoneal inoculation of EAT cells in mice and the formation of a solid tumor by the subcutaneous injection of the cells in rat paw. The development of the tumor was associated with an increase in mouse total cell counts in bone marrow (10.8-fold), ascitic fluid (14.6-fold), and blood (12.6-fold). R-954 (2mg/kg, s.c.) significantly reduced the ascitic fluid volume (63.7%) and the mouse weight gain (30.5%) after 10 consecutive days of treatment. The B(1) antagonist as well as the anti-neoplasic drug vincristine also significantly inhibited the increase in total cell count in bone marrow, ascitic fluid, and blood. R-954 reduced significantly the total protein extravasation (57.3%), the production of nitric oxide (56%), PGE(2) production (82%), and TNFα release (85.7%) in mice peritoneal cavity whereas vincristine reduced the release of these inflammatory mediators by 84-94%. The increase in paw edema after intraplantar injection of EAT cells was reduced by approximately 52% by either R-954 or vincristine treatment. In conclusion, this study presents for the first time the antitumoral activity of a new bradykinin B(1) receptor antagonist on ascitic and solid tumors induced by Ehrlich cell inoculation in mice and rats. PMID:21835216

  17. Gallium maltolate inhibits human cutaneous T-cell lymphoma tumor development in mice.

    PubMed

    Wu, Xuesong; Wang, Timothy W; Lessmann, George M; Saleh, Jamal; Liu, Xiping; Chitambar, Christopher R; Hwang, Sam T

    2015-03-01

    Cutaneous T-cell lymphomas (CTCLs) represent a heterogeneous group of non-Hodgkin's lymphoma characterized by an accumulation of malignant CD4 T cells in the skin. The group IIIa metal salt, gallium nitrate, is known to have antineoplastic activity against B-cell lymphoma in humans, but its activity in CTCLs has not been elaborated in detail. Herein, we examined the antineoplastic efficacy of a gallium compound, gallium maltolate (GaM), in vitro and in vivo with murine models of CTCLs. GaM inhibited cell growth and induced apoptosis of cultured CTCL cells. In human CTCL xenograft models, peritumoral injection of GaM limited the growth of CTCL cells, shown by fewer tumor formations, smaller tumor sizes, and decreased neovascularization in tumor microenvironment. To identify key signaling pathways that have a role in GaM-mediated reduction of tumor growth, we analyzed inflammatory cytokines, as well as signal transduction pathways in CTCL cells treated by GaM. IFN-γ-induced chemokines and IL-13 were found to be notably increased in GaM-treated CTCL cells. However, immunosuppressive cytokines, such as IL-10, were decreased with GaM treatment. Interestingly, both oxidative stress and p53 pathways were involved in GaM-induced cytotoxicity. These results warrant further investigation of GaM as a therapeutic agent for CTCLs. PMID:25371972

  18. Novel immunocytokine IL12-SS1 (Fv) inhibits mesothelioma tumor growth in nude mice.

    PubMed

    Kim, Heungnam; Gao, Wei; Ho, Mitchell

    2013-01-01

    Mesothelin is a glycosylphosphatidylinositol-anchored glycoprotein that is highly expressed on the cell surface of malignant mesothelioma. Monoclonal antibodies against mesothelin are being evaluated for the treatment of mesothelioma. Immunocytokines represent a novel class of armed antibodies. To provide an alternative approach to current mesothelin-targeted antibody therapies, we have developed a novel immunocytokine based on interleukin-12 (IL12) and the SS1 Fv specific for mesothelin. IL12 possesses potent anti-tumor activity in a wide variety of solid tumors. The newly-developed recombinant immunocytokine, IL12-SS1 (Fv), was produced in insect cells using a baculovirus-insect cell expression system. The SS1 single-chain Fv was fused to the C terminus of the p35 subunit of IL12 through a short linker (GSADGG). The single-chain IL12-SS1 (Fv) immunocytokine bound native mesothelin proteins on malignant mesothelioma (NCI-H226) and ovarian (OVCAR-3) cells as well as recombinant mesothelin on A431/H9 cells. The immunocytokine retained sufficient bioactivity of IL12 and significantly inhibited human malignant mesothelioma (NCI-H226) grown in the peritoneal cavity of nude mice and showed comparable anti-tumor activity to that of the SS1P immunotoxin. IL12-SS1 (Fv) is the first reported immunocytokine to mesothelin-positive tumors and may be an attractive addition to mesothelin-targeted cancer therapies. PMID:24260587

  19. Genistein sensitizes sarcoma cells in vitro and in vivo by enhancing apoptosis and by inhibiting DSB repair pathways

    PubMed Central

    Liu, X.X.; Sun, C.; Jin, X.D.; Li, P.; Zheng, X.G.; Zhao, T.; Li, Q.

    2016-01-01

    The aim of this work was to investigate the radiosensitization effects of genistein on mice sarcoma cells and the corresponding biological mechanisms in vitro and in vivo. Using the non-toxic dosage of 10 μM genistein, the sensitizer enhancement ratios after exposure to X-rays at 50% cell survival (IC50) was 1.45 for S180 cells. For mice cotreated with genistein and X-rays, the excised tumor tissues had reduced blood vessels and decreased size and volume compared with the control and irradiation-only groups. Moreover, a significant increase in apoptosis was accompanied by upregulation of Bax and downregulation of Bcl-2 in the mitochondria, and lots of cytochrome c being transferred to the cytoplasm. Furthermore, X-rays combined with genistein inhibited the activity of DNA-PKcs, so DNA-injured sites were dominated by Ku70/80, leading to incompleteness of homologous recombination (HR) and non-homologous end-joining (NHEJ) repairs and the eventual occurrence of cell apoptosis. Our study, for the first time, demonstrated that genistein sensitized sarcoma cells to X-rays and that this radiosensitizing effect depended on induction of the mitochondrial apoptosis pathway and inhibition of the double-strand break (DSB) repair pathways. PMID:26922091

  20. Genistein sensitizes sarcoma cells in vitro and in vivo by enhancing apoptosis and by inhibiting DSB repair pathways.

    PubMed

    Liu, X X; Sun, C; Jin, X D; Li, P; Zheng, X G; Zhao, T; Li, Q

    2016-06-01

    The aim of this work was to investigate the radiosensitization effects of genistein on mice sarcoma cells and the corresponding biological mechanisms in vitro and in vivo Using the non-toxic dosage of 10 μM genistein, the sensitizer enhancement ratios after exposure to X-rays at 50% cell survival (IC50) was 1.45 for S180 cells. For mice cotreated with genistein and X-rays, the excised tumor tissues had reduced blood vessels and decreased size and volume compared with the control and irradiation-only groups. Moreover, a significant increase in apoptosis was accompanied by upregulation of Bax and downregulation of Bcl-2 in the mitochondria, and lots of cytochrome c being transferred to the cytoplasm. Furthermore, X-rays combined with genistein inhibited the activity of DNA-PKcs, so DNA-injured sites were dominated by Ku70/80, leading to incompleteness of homologous recombination (HR) and non-homologous end-joining (NHEJ) repairs and the eventual occurrence of cell apoptosis. Our study, for the first time, demonstrated that genistein sensitized sarcoma cells to X-rays and that this radiosensitizing effect depended on induction of the mitochondrial apoptosis pathway and inhibition of the double-strand break (DSB) repair pathways. PMID:26922091

  1. Hypoxia targeted carbon nanotubes as a sensitive contrast agent for photoacoustic imaging of tumors

    NASA Astrophysics Data System (ADS)

    Zanganeh, Saeid; Aguirre, Andres; Biswal, Nrusingh C.; Pavlik, Christopher; Smith, Michael B.; Alqasemi, Umar; Li, Hai; Zhu, Quing

    2011-03-01

    Development of new and efficient contrast agents is of fundamental importance to improve detection sensitivity of smaller lesions. Within the family of nanomaterials, carbon nanotubes (CNT) not only have emerged as a new alternative and efficient transporter and translocater of therapeutic molecules but also as a photoacoustic molecular imaging agent owing to its strong optical absorption in the near-infrared region. Drugs, Antibodies and nucleic acids could functionalize the CNT and prepare an appropriate system for delivering the cargos to cells and organs. In this work, we present a novel photoacoustic contrast agent which is based on a unique hypoxic marker in the near infrared region, 2-nitroimidazole -bis carboxylic acid derivative of Indocyanine Green conjugated to single walled carbon nanotube (SWCNT-2nitroimidazole-ICG). The 2-nitroimidazole-ICG has an absorption peak at 755 nm and an extinction coefficient of 20,5222 M-1cm-1. The conjugation of this marker with SWCNT shows more than 25 times enhancement of optical absorption of carbon nanotubes in the near infrared region. This new conjugate has been optically evaluated and shows promising results for high contrast photoacoustic imaging of deeply located tumors. The conjugate specifically targets tumor hypoxia, an important indicator of tumor metabolism and tumor therapeutic response. The detection sensitivity of the new contrast agent has been evaluated in-vitro cell lines and with in-vivo tumors in mice.

  2. Delaying mitotic exit downregulates FLIP expression and strongly sensitizes tumor cells to TRAIL.

    PubMed

    Sánchez-Pérez, T; Medema, R H; López-Rivas, A

    2015-01-29

    Many of the current antitumor therapeutic strategies are based on the perturbation of the cell cycle, especially during mitosis. Antimitotic drugs trigger mitotic checkpoint activation, mitotic arrest and eventually cell death. However, mitotic slippage represents a major mechanism of resistance to these treatments. In an attempt to circumvent the process of slippage, targeting mitotic exit has been proposed as a better strategy to kill tumor cells. In this study, we show that treatments that induce mitotic checkpoint activation and mitotic arrest downregulate FLICE-like inhibitory protein (FLIP) levels and sensitize several tumor cell lines to TRAIL (tumor necrosis factor-related apoptosis-inducing ligand)-induced apoptosis. Interestingly, we also demonstrate that in absence of mitotic checkpoint activation, mitotic arrest induced either by Cdc20 knockdown or overexpression of nondegradable cyclin B is sufficient to induce both FLIP downregulation and sensitivity to TRAIL. In summary, our data suggest that a combination of antimitotic drugs targeting cyclin B degradation and TRAIL might prevent mitotic slippage and allow tumor cells to reach the threshold for apoptosis induction, thereby facilitating tumor suppression. PMID:24488010

  3. Targeted two-photon PDT photo-sensitizers for the treatment of subcutaneous tumors

    NASA Astrophysics Data System (ADS)

    Spangler, C. W.; Rebane, A.; Starkey, J.; Drobizhev, M.

    2009-06-01

    New porphyrin-based photo-sensitizers have been designed, synthesized and characterized that exhibit greatly enhanced intrinsic two-photon absorption. These new photo-sensitizers have been incorporated into triad formulations that also incorporate Near-infrared (NIR) imaging agents, and small-molecule targeting agents that direct the triads to cancerous tumors' over-expressed receptor sites. PDT can be initiated deep into the tissue transparency window at 780-800 nm utilizing a regeneratively amplified Ti:sapphire laser using 100-150 fs pulses of 600-800 mW. Human tumor xenografts of human breast cancer (MDA-MB-231) and both small SCLC (NCI-H69) and NSCLC (A-459) have been successfully treated using octreotate targeting of over-expressed SST2 receptors. In particular, the lung cancer xenografts can be successfully treated by irradiating from the side of the mouse opposite the implanted tumor, thereby passing through ca. 2 cm of mouse skin, tissue and organs with no discernible damage to healthy tissue while causing regression in the tumors. These results suggest a new PDT paradigm for the noninvasive treatment of subcutaneous tumors, including the possibility that the targeting moiety could be matched to individual patient genetic profiles (patient-specific therapeutics).

  4. B7h triggering inhibits the migration of tumor cell lines.

    PubMed

    Dianzani, Chiara; Minelli, Rosalba; Gigliotti, Casimiro Luca; Occhipinti, Sergio; Giovarelli, Mirella; Conti, Laura; Boggio, Elena; Shivakumar, Yogesh; Baldanzi, Gianluca; Malacarne, Valeria; Orilieri, Elisabetta; Cappellano, Giuseppe; Fantozzi, Roberto; Sblattero, Daniele; Yagi, Junji; Rojo, Josè Maria; Chiocchetti, Annalisa; Dianzani, Umberto

    2014-05-15

    Vascular endothelial cells (ECs) and several cancer cells express B7h, which is the ligand of the ICOS T cell costimulatory molecule. We have previously shown that B7h triggering via a soluble form of ICOS (ICOS-Fc) inhibits the adhesion of polymorphonuclear and tumor cell lines to HUVECs; thus, we suggested that ICOS-Fc may act as an anti-inflammatory and antitumor agent. Because cancer cell migration and angiogenesis are crucial for metastasis dissemination, the aim of this work was to evaluate the effect of ICOS-Fc on the migration of cancer cells and ECs. ICOS-Fc specifically inhibited the migration of HUVECs, human dermal lymphatic ECs, and the HT29, HCT116, PC-3, HepG2, JR8, and M14 tumor cell lines expressing high levels of B7h, whereas it was ineffective in the RPMI7932, PCF-2, LM, and BHT-101 cell lines expressing low levels of B7h. Furthermore, ICOS-Fc downmodulated hepatocyte growth factor facilitated the epithelial-to-mesenchymal transition in HepG2 cells. Moreover, ICOS-Fc downmodulated the phosphorylation of focal adhesion kinase and the expression of β-Pix in both HUVECs and tumor cell lines. Finally, treatment with ICOS-Fc inhibited the development of lung metastases upon injection of NOD-SCID-IL2Rγnull mice with CF-PAC1 cells, as well as C57BL/6 mice with B16-F10 cells. Therefore, the B7h-ICOS interaction may modulate the spread of cancer metastases, which suggests the novel use of ICOS-Fc as an immunomodulatory drug. However, in the B16-F10-metastasized lungs, ICOS-Fc also increased IL-17A/RORc and decreased IL-10/Foxp3 expression, which indicates that it also exerts positive effects on the antitumor immune response. PMID:24729612

  5. Ginseng saponin metabolite 20(S)-protopanaxadiol inhibits tumor growth by targeting multiple cancer signaling pathways

    PubMed Central

    GAO, JIAN-LI; LV, GUI-YUAN; HE, BAI-CHENG; ZHANG, BING-QIANG; ZHANG, HONGYU; WANG, NING; WANG, CHONG-ZHI; DU, WEI; YUAN, CHUN-SU; HE, TONG-CHUAN

    2013-01-01

    Plant-derived active constituents and their semi-synthetic or synthetic analogs have served as major sources of anticancer drugs. 20(S)-protopanaxadiol (PPD) is a metabolite of ginseng saponin of both American ginseng (Panax quinquefolius L.) and Asian ginseng (Panax ginseng C.A. Meyer). We previously demonstrated that ginsenoside Rg3, a glucoside precursor of PPD, exhibits anti-proliferative effects on HCT116 cells and reduces tumor size in a xenograft model. Our subsequent study indicated that PPD has more potent antitumor activity than that of Rg3 in vitro although the mechanism underlying the anticancer activity of PPD remains to be defined. Here, we investigated the mechanism underlying the anticancer activity of PPD in human cancer cells in vitro and in vivo. PPD was shown to inhibit growth and induce cell cycle arrest in HCT116 cells. The in vivo studies indicate that PPD inhibits xenograft tumor growth in athymic nude mice bearing HCT116 cells. The xenograft tumor size was significantly reduced when the animals were treated with PPD (30 mg/kg body weight) for 3 weeks. When the expression of previously identified Rg3 targets, A kinase (PRKA) anchor protein 8 (AKAP8L) and phosphatidylinositol transfer protein α (PITPNA), was analyzed, PPD was shown to inhibit the expression of PITPNA while upregulating AKAP8L expression in HCT116 cells. Pathway-specific reporter assays indicated that PPD effectively suppressed the NF-κB, JNK and MAPK/ERK signaling pathways. Taken together, our results suggest that the anticancer activity of PPD in colon cancer cells may be mediated through targeting NF-κB, JNK and MAPK/ERK signaling pathways, although the detailed mechanisms underlying the anticancer mode of PPD action need to be fully elucidated. PMID:23633038

  6. The novel Aryl hydrocarbon receptor inhibitor biseugenol inhibits gastric tumor growth and peritoneal dissemination

    PubMed Central

    Lai, De-Wei; Karlsson, Anna Isabella; Wang, Keh-Bin; Chen, Yi-Ching; Shen, Chin-Chang; Wu, Sheng-Mao; Liu, Chia-Yu; Tien, Hsing-Ru; Peng, Yen-Chun; Jan, Yee-Jee; Chao, Te-Hsin; Lan, Keng-Hsin; Arbiser, Jack L.; Sheu, Meei-Ling

    2014-01-01

    Biseugenol (Eug) is known to antiproliferative of cancer cells; however, to date, the antiperitoneal dissemination effects have not been studied in any mouse cancer model. In this study, Aryl hydrocarbon receptor (AhR) expression was associated with lymph node and distant metastasis in patients with gastric cancer and was correlated with clinicolpathological pattern. We evaluated the antiperitoneal dissemination potential of knockdown AhR and Biseugenol in cancer mouse model and assessed mesenchymal characteristics. Our results demonstrate that tumor growth, peritoneal dissemination and peritoneum or organ metastasis implanted MKN45 cells were significantly decreased in shAhR and Biseugenol-treated mice and that endoplasmic reticulum (ER) stress was caused. Biseugenol-exposure tumors showed acquired epithelial features such as phosphorylation of E-cadherin, cytokeratin-18 and loss mesenchymal signature Snail, but not vimentin regulation. Snail expression, through AhR activation, is an epithelial-to-mesenchymal transition (EMT) determinant. Moreover, Biseugenol enhanced Calpain-10 (Calp-10) and AhR interaction resulted in Snail downregulation. The effect of shCalpain-10 in cancer cells was associated with inactivation of AhR/Snail promoter binding activity. Inhibition of Calpain-10 in gastric cancer cells by short hairpin RNA or pharmacological inhibitor was found to effectively reduced growth ability and vessel density in vivo. Importantly, knockdown of AhR completed abrogated peritoneal dissemination. Herein, Biseugenol targeting ER stress provokes Calpain-10 activity, sequentially induces reversal of EMT and apoptosis via AhR may involve the paralleling processes. Taken together, these data suggest that Calpain-10 activation and AhR inhibition by Biseugenol impedes both gastric tumor growth and peritoneal dissemination by inducing ER stress and inhibiting EMT. PMID:25226618

  7. The Motor Protein KIF14 Inhibits Tumor Growth and Cancer Metastasis in Lung Adenocarcinoma

    PubMed Central

    Hung, Pei-Fang; Hong, Tse-Ming; Hsu, Yi-Chiung; Chen, Hsuan-Yu; Chang, Yih-Leong; Wu, Chen-Tu; Chang, Gee-Chen; Jou, Yuh-Shan

    2013-01-01

    The motor protein kinesin superfamily proteins (KIFs) are involved in cancer progression. The depletion of one of the KIFs, KIF14, might delay the metaphase-to-anaphase transition, resulting in a binucleated status, which enhances tumor progression; however, the exact correlation between KIF14 and cancer progression remains ambiguous. In this study, using loss of heterozygosity and array comparative genomic hybridization analyses, we observed a 30% loss in the regions surrounding KIF14 on chromosome 1q in lung adenocarcinomas. In addition, the protein expression levels of KIF14 in 122 lung adenocarcinomas also indicated that approximately 30% of adenocarcinomas showed KIF14 down-regulation compared with the expression in the bronchial epithelial cells of adjacent normal counterparts. In addition, the reduced expression of KIF14 mRNA or proteins was correlated with poor overall survival (P = 0.0158 and <0.0001, respectively), and the protein levels were also inversely correlated with metastasis (P<0.0001). The overexpression of KIF14 in lung adenocarcinoma cells inhibited anchorage-independent growth in vitro and xenograft tumor growth in vivo. The overexpression and silencing of KIF14 also inhibited or enhanced cancer cell migration, invasion and adhesion to the extracellular matrix proteins laminin and collagen IV. Furthermore, we detected the adhesion molecules cadherin 11 (CDH11) and melanoma cell adhesion molecule (MCAM) as cargo on KIF14. The overexpression and silencing of KIF14 enhanced or reduced the recruitment of CDH11 in the membrane fraction, suggesting that KIF14 might act through recruiting adhesion molecules to the cell membrane and modulating cell adhesive, migratory and invasive properties. Thus, KIF14 might inhibit tumor growth and cancer metastasis in lung adenocarcinomas. PMID:23626713

  8. The motor protein KIF14 inhibits tumor growth and cancer metastasis in lung adenocarcinoma.

    PubMed

    Hung, Pei-Fang; Hong, Tse-Ming; Hsu, Yi-Chiung; Chen, Hsuan-Yu; Chang, Yih-Leong; Wu, Chen-Tu; Chang, Gee-Chen; Jou, Yuh-Shan; Pan, Szu-Hua; Yang, Pan-Chyr

    2013-01-01

    The motor protein kinesin superfamily proteins (KIFs) are involved in cancer progression. The depletion of one of the KIFs, KIF14, might delay the metaphase-to-anaphase transition, resulting in a binucleated status, which enhances tumor progression; however, the exact correlation between KIF14 and cancer progression remains ambiguous. In this study, using loss of heterozygosity and array comparative genomic hybridization analyses, we observed a 30% loss in the regions surrounding KIF14 on chromosome 1q in lung adenocarcinomas. In addition, the protein expression levels of KIF14 in 122 lung adenocarcinomas also indicated that approximately 30% of adenocarcinomas showed KIF14 down-regulation compared with the expression in the bronchial epithelial cells of adjacent normal counterparts. In addition, the reduced expression of KIF14 mRNA or proteins was correlated with poor overall survival (P = 0.0158 and <0.0001, respectively), and the protein levels were also inversely correlated with metastasis (P<0.0001). The overexpression of KIF14 in lung adenocarcinoma cells inhibited anchorage-independent growth in vitro and xenograft tumor growth in vivo. The overexpression and silencing of KIF14 also inhibited or enhanced cancer cell migration, invasion and adhesion to the extracellular matrix proteins laminin and collagen IV. Furthermore, we detected the adhesion molecules cadherin 11 (CDH11) and melanoma cell adhesion molecule (MCAM) as cargo on KIF14. The overexpression and silencing of KIF14 enhanced or reduced the recruitment of CDH11 in the membrane fraction, suggesting that KIF14 might act through recruiting adhesion molecules to the cell membrane and modulating cell adhesive, migratory and invasive properties. Thus, KIF14 might inhibit tumor growth and cancer metastasis in lung adenocarcinomas. PMID:23626713

  9. Tumor-selective proteotoxicity of verteporfin inhibits colon cancer progression independently of YAP1#

    PubMed Central

    Zhang, Huabing; Ramakrishnan, Sadeesh K.; Triner, Daniel; Centofanti, Brook; Maitra, Dhiman; Győrffy, Balázs; Sebolt-Leopold, Judith S.; Dame, Michael K.; Varani, James; Brenner, Dean E.; Fearon, Eric R.; Omary, M. Bishr; Shah, Yatrik M.

    2016-01-01

    Yes-associated protein 1 (YAP1) is a transcriptional coactivator in the Hippo signaling pathway. Increased YAP1- activity promotes the growth of tumors, including that of colorectal cancer (CRC). Verteporfin, a drug that enhances phototherapy to treat neovascular macular degeneration, is an inhibitor of YAP1. Here, we found that verteporfin inhibited tumor growth independently of its effects on YAP1 or the related protein TAZ in genetic or chemical-induced mouse models of CRC, in patient-derived xenografts and in enteroid models of CRC. Instead, verteporfin exhibited in vivo selectivity for killing tumor cells in part by impairing the global clearance of high molecular weight oligomerized proteins, particularly p62 (a sequestrome involved in autophagy) and STAT3 (a transcription factor). Verteporfin inhibited cytokine-induced STAT3 activity and cell proliferation and reduced the viabilty of cultured CRC cells. Although verteporfin accumulated to a greater extent in normal cells than in tumor cells in vivo, experiments with cultured cells indicated that the normal cells efficiently cleared verteporfin-induced protein oligomers through autophagic and proteasomal pathways. Culturing CRC cells in hypoxic or nutrient-deprived conditions (modeling a typical CRC microenvironment) impaired the clearance of protein oligomers and resulted in cell death; whereas culturing cells in normoxic or glucose-replete conditions protected cell viability and proliferation in the presence of verteporfin. Furthermore, verteporfin suppressed the proliferation of other cancer cell lines even in the absence of YAP1, suggesting that verteporfin may be effective against multiple types of solid cancers. PMID:26443705

  10. A novel nanoparticle containing neuritin peptide with grp170 induces a CTL response to inhibit tumor growth.

    PubMed

    Yuan, Bangqing; Shen, Hanchao; Su, Tonggang; Lin, Li; Chen, Ting; Yang, Zhao

    2015-10-01

    Malignant glioma is among the most challenging of all cancers to treat successfully. Despite recent advances in surgery, radiotherapy and chemotherapy, current treatment regimens have only a marginal impact on patient survival. In this study, we constructed a novel nanoparticle containing neuritin peptide with grp170. The nanoparticle could elicit a neuritin-specific cytotoxic T lymphocyte response to lyse glioma cells in vitro. In addition, the nanoparticle could inhibit tumor growth and improve the lifespan of tumor-bearing mice in vivo. Taken together, the results demonstrated that the nanoparticle can inhibit tumor growth and represents a promising therapy for glioma. PMID:26290143

  11. Nanoparticle mediated silencing of DNA repair sensitizes pediatric brain tumor cells to γ-irradiation

    PubMed Central

    Kievit, Forrest M.; Stephen, Zachary R.; Wang, Kui; Dayringer, Christopher J.; Sham, Jonathan G.; Ellenbogen, Richard G.; Silber, John R.; Zhang, Miqin

    2015-01-01

    Medulloblastoma (MB) and ependymoma (EP) are the most common pediatric brain tumors, afflicting 3,000 children annually. Radiotherapy (RT) is an integral component in the treatment of these tumors; however, the improvement in survival is often accompanied by radiation-induced adverse developmental and psychosocial sequelae. Therefore, there is an urgent need to develop strategies that can increase the sensitivity of brain tumors cells to RT while sparing adjacent healthy brain tissue. Apurinic endonuclease 1 (Ape1), an enzyme in the base excision repair pathway, has been implicated in radiation resistance in cancer. Pharmacological and specificity limitations inherent to small molecule inhibitors of Ape1 have hindered their clinical development. Here we report on a nanoparticle (NP) based siRNA delivery vehicle for knocking down Ape1 expression and sensitizing pediatric brain tumor cells to RT. The NP comprises a superparamagnetic iron oxide core coated with a biocompatible, biodegradable coating of chitosan, polyethylene glycol (PEG), and polyethyleneimine (PEI) that is able to bind and protect siRNA from degradation and to deliver siRNA to the perinuclear region of target cells. NPs loaded with siRNA against Ape1 (NP:siApe1) knocked down Ape1 expression over 75% in MB and EP cells, and reduced Ape1 activity by 80%. This reduction in Ape1 activity correlated with increased DNA damage post-irradiation, which resulted in decreased cell survival in clonogenic assays. The sensitization was specific to therapies generating abasic lesions as evidenced by NP:siRNA not increasing sensitivity to paclitaxel, a microtubule disrupting agent. Our results indicate NP-mediated delivery of siApe1 is a promising strategy for circumventing pediatric brain tumor resistance to RT. PMID:25681012

  12. Pertussis toxin inhibits somatostatin-induced K/sup +/ conductance in human pituitary tumor cells

    SciTech Connect

    Yamashita, N.; Kojima, I.; Shibuya, N.; Ogata, E.

    1987-07-01

    The effect of pertussis toxin on somatostatin-induced K/sup +/ current was examined in dissociated human pituitary tumor cells obtained from two acromegalic patients. Somatostatin-induced hyperpolarization or K/sup +/ current was observed in 20 of 23 cells in adenoma 1 and 10 of 11 cells in adenoma 2. After treatment with pertussis toxin for 24 h, these responses were completely suppressed (0/14 in adenoma, 1, 0/10 in adenoma 2). Spontaneous action potentials, K/sup +/, Na/sup +/, and Ca/sup 2 +/ currents were well preserved after pertussis toxin treatment. When crude membrane fraction was incubated with (/sup 32/P)NAD, a 41K protein was ADP-ribosylated by pertussis toxin. Hormone release was inhibited by somatostatin and this inhibition was blocked by pertussis toxin treatment.

  13. Merlin's tumor suppression linked to inhibition of the E3 ubiquitin ligase CRL4DCAF1

    PubMed Central

    Li, Wei

    2010-01-01

    The mechanism by which the FERM domain protein Merlin, encoded by the tumor suppressor NF2, restrains cell proliferation is poorly understood. Prior studies have suggested that Merlin exerts its antimitogenic effect by interacting with multiple signaling proteins located at or near the plasma membrane. We have recently observed that Merlin translocates into the nucleus and binds to and inhibits the E3 ubiquitin ligase CRL4DCAF1. Genetic evidence indicates that inactivation of Merlin induces oncogenic gene expression, hyperproliferation, and tumorigenicity by unleashing the activity of CRL4DCAF1. In addition to providing a potential explanation for the diverse effects that loss of Merlin exerts in multiple cell types, these findings suggest that compounds inhibiting CRL4DCAF1 may display therapeutic efficacy in Neurofibromatosis type 2 and other cancers driven by Merlin inactivation. PMID:21084862

  14. Granzyme B-based cytolytic fusion protein targeting EpCAM specifically kills triple negative breast cancer cells in vitro and inhibits tumor growth in a subcutaneous mouse tumor model.

    PubMed

    Amoury, Manal; Kolberg, Katharina; Pham, Anh-Tuan; Hristodorov, Dmitrij; Mladenov, Radoslav; Di Fiore, Stefano; Helfrich, Wijnand; Kiessling, Fabian; Fischer, Rainer; Pardo, Alessa; Thepen, Theophilus; Hussain, Ahmad F; Nachreiner, Thomas; Barth, Stefan

    2016-03-28

    Triple-negative breast cancer (TNBC) is associated with poor prognosis and high prevalence among young premenopausal women. Unlike in other breast cancer subtypes, no targeted therapy is currently available. Overexpression of epithelial cell adhesion molecule (EpCAM) in 60% of TNBC tumors correlates with poorer prognosis and is associated with cancer stem cell phenotype. Thus, selective elimination of EpCAM(+) TNBC tumor cells is of clinical importance. Therefore, we constructed a fully human targeted cytolytic fusion protein, designated GbR201K-αEpCAM(scFv), in which an EpCAM-selective single-chain antibody fragment (scFv) is genetically fused to a granzyme B (Gb) mutant with reduced sensitivity to its natural inhibitor serpin B9. In vitro studies confirmed its specific binding, internalization and cytotoxicity toward a panel of EpCAM-expressing TNBC cells. Biodistribution kinetics and tumor-targeting efficacy using MDA-MB-468 cells in a human TNBC xenograft model in mice revealed selective accumulation of GbR201K-αEpCAM(scFv) in the tumors after i.v. injection. Moreover, treatment of tumor-bearing mice demonstrated a prominent inhibition of tumor growth of up to 50 % in this proof-of-concept study. Taken together, our results indicate that GbR201K-αEpCAM(scFv) is a promising novel targeted therapeutic for the treatment of TNBC. PMID:26806809

  15. Ultrasound Targeted Microbubble Destruction-Mediated Delivery of a Transcription Factor Decoy Inhibits STAT3 Signaling and Tumor Growth

    PubMed Central

    Kopechek, Jonathan A.; Carson, Andrew R.; McTiernan, Charles F.; Chen, Xucai; Hasjim, Bima; Lavery, Linda; Sen, Malabika; Grandis, Jennifer R.; Villanueva, Flordeliza S.

    2015-01-01

    Signal transducer and activator of transcription 3 (STAT3) is constitutively activated in many cancers where it acts to promote tumor progression. A STAT3-specific transcription factor decoy has been developed to suppress STAT3 downstream signaling, but a delivery strategy is needed to improve clinical translation. Ultrasound-targeted microbubble destruction (UTMD) has been shown to enhance image-guided local delivery of molecular therapeutics to a target site. The objective of this study was to deliver STAT3 decoy to squamous cell carcinoma (SCC) tumors using UTMD to disrupt STAT3 signaling and inhibit tumor growth. Studies performed demonstrated that UTMD treatment with STAT3 decoy-loaded microbubbles inhibited STAT3 signaling in SCC cells in vitro. Studies performed in vivo demonstrated that UTMD treatment with STAT3 decoy-loaded microbubbles induced significant tumor growth inhibition (31-51% reduced tumor volume vs. controls, p < 0.05) in mice bearing SCC tumors. Furthermore, expression of STAT3 downstream target genes (Bcl-xL and cyclin D1) was significantly reduced (34-39%, p < 0.05) in tumors receiving UTMD treatment with STAT3 decoy-loaded microbubbles compared to controls. In addition, the quantity of radiolabeled STAT3 decoy detected in tumors eight hours after treatment was significantly higher with UTMD treatment compared to controls (70-150%, p < 0.05). This study demonstrates that UTMD can increase delivery of a transcription factor decoy to tumors in vivo and that the decoy can inhibit STAT3 signaling and tumor growth. These results suggest that UTMD treatment holds potential for clinical use to increase the concentration of a transcription factor signaling inhibitor in the tumor. PMID:26681983

  16. The Rac Inhibitor EHop-016 Inhibits Mammary Tumor Growth and Metastasis in a Nude Mouse Model

    PubMed Central

    Castillo-Pichardo, Linette; Humphries-Bickley, Tessa; De La Parra, Columba; Forestier-Roman, Ingrid; Martinez-Ferrer, Magaly; Hernandez, Eliud; Vlaar, Cornelis; Ferrer-Acosta, Yancy; Washington, Anthony V.; Cubano, Luis A.; Rodriguez-Orengo, Jose; Dharmawardhane, Suranganie

    2014-01-01

    Metastatic disease still lacks effective treatments, and remains the primary cause of cancer mortality. Therefore, there is a critical need to develop better strategies to inhibit metastatic cancer. The Rho family GTPase Rac is an ideal target for anti-metastatic cancer therapy, because Rac is a key molecular switch that is activated by a myriad of cell surface receptors to promote cancer cell migration/invasion and survival. Previously, we reported the design and development of EHop-016, a small molecule compound, which inhibits Rac activity of metastatic cancer cells with an IC50 of 1 μM. EHop-016 also inhibits the activity of the Rac downstream effector p21-activated kinase (PAK), lamellipodia extension, and cell migration in metastatic cancer cells. Herein, we tested the efficacy of EHop-016 in a nude mouse model of experimental metastasis, where EHop-016 administration at 25 mg/kg body weight (BW) significantly reduced mammary fat pad tumor growth, metastasis, and angiogenesis. As quantified by UPLC MS/MS, EHop-016 was detectable in the plasma of nude mice at 17 to 23 ng/ml levels at 12 h following intraperitoneal (i.p.) administration of 10 to 25 mg/kg BW EHop-016. The EHop-016 mediated inhibition of angiogenesis In Vivo was confirmed by immunohistochemistry of excised tumors and by In Vitro tube formation assays of endothelial cells. Moreover, EHop-016 affected cell viability by down-regulating Akt and Jun kinase activities and c-Myc and Cyclin D expression, as well as increasing caspase 3/7 activities in metastatic cancer cells. In conclusion, EHop-016 has potential as an anticancer compound to block cancer progression via multiple Rac-directed mechanisms. PMID:25389450

  17. MAP Kinase Inhibition Promotes T Cell and Anti-tumor Activity in Combination with PD-L1 Checkpoint Blockade.

    PubMed

    Ebert, Peter J R; Cheung, Jeanne; Yang, Yagai; McNamara, Erin; Hong, Rebecca; Moskalenko, Marina; Gould, Stephen E; Maecker, Heather; Irving, Bryan A; Kim, Jeong M; Belvin, Marcia; Mellman, Ira

    2016-03-15

    Targeted inhibition of mitogen-activated protein kinase (MAPK) kinase (MEK) can induce regression of tumors bearing activating mutations in the Ras pathway but rarely leads to tumor eradication. Although combining MEK inhibition with T-cell-directed immunotherapy might lead to more durable efficacy, T cell responses are themselves at least partially dependent on MEK activity. We show here that MEK inhibition did profoundly block naive CD8(+) T cell priming in tumor-bearing mice, but actually increased the number of effector-phenotype antigen-specific CD8(+) T cells within the tumor. MEK inhibition protected tumor-infiltrating CD8(+) T cells from death driven by chronic TCR stimulation while sparing cytotoxic activity. Combining MEK inhibition with anti-programmed death-ligand 1 (PD-L1) resulted in synergistic and durable tumor regression even where either agent alone was only modestly effective. Thus, despite the central importance of the MAP kinase pathway in some aspects of T cell function, MEK-targeted agents can be compatible with T-cell-dependent immunotherapy. PMID:26944201

  18. Tumor indoleamine 2,3-dioxygenase (IDO) inhibits CD19-CAR T cells and is downregulated by lymphodepleting drugs

    PubMed Central

    Ninomiya, Soranobu; Narala, Neeharika; Huye, Leslie; Yagyu, Shigeki; Savoldo, Barbara; Dotti, Gianpietro; Heslop, Helen E.; Brenner, Malcolm K.; Rooney, Cliona M.

    2015-01-01

    Although T cells expressing CD19-specific chimeric antigen receptors (CARs) are a promising new therapy for B-cell malignancies, objective responses are observed at lower frequencies in patients with lymphoma than in those with acute B-cell leukemia. We postulated that the tumor microenvironment suppresses CAR-expressing T cells (CARTs) through the activity of indoleamine 2,3-dioxygenase (IDO), an intracellular enzyme that converts tryptophan into metabolites that inhibit T-cell activity. To investigate the effects of tumor IDO on CD19-CART therapy, we used a xenograft lymphoma model expressing IDO as a transgene. CD19-CARTs inhibited IDO-negative tumor growth but had no effect on IDO-positive tumors. An IDO inhibitor (1-methyl-tryptophan) restored IDO-positive tumor control. Moreover, tryptophan metabolites inhibited interleukin (IL)-2–, IL-7–, and IL-15–dependent expansion of CARTs; diminished their proliferation, cytotoxicity, and cytokine secretion in vitro in response to CD19 recognition; and increased their apoptosis. Inhibition of CD19-CARTs was not mitigated by the incorporation of costimulatory domains, such as 4-1BB, into the CD19-CAR. Finally, we found that fludarabine and cyclophosphamide, frequently used before CART administration, downregulated IDO expression in lymphoma cells and improved the antitumor activity of CD19-CART i