Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0598934 (tumor growth)
 58,965 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chemotherapeutic drugs are usually designed to induce cancer cell death via cell cycle arrest and/or apoptosis pathways. In this study, we used the chemical drug 15,16-dihydrotanshinone I (DHTS) to inhibit breast cancer cell proliferation and tumor growth, and investigate the underlying molecular mechanisms. Human breast cancer cell lines MCF-7 and MDA-MB-231 were both used in this study, and DHTS was found to significantly decrease cell proliferation by a dose-dependent manner in both cells. Flow cytometry indicated that DHTS induced G1 phase arrest in synchronous MCF-7 and MDA-MB-231 cells. When analyzing the expression of cell cycle-related proteins, we found that DHTS reduced cyclin D1, cyclin D3, cyclin E, and CDK4 expression, and increased CDK inhibitor p27 expression in a dose-dependent manner. In addition, DHTS inhibited the kinase activities of CDK2 and CDK4 by an immunocomplex kinase assay. In addition, DHTS also induced apoptosis in both cells through mainly mitochondrial apoptosis pathways. We found that DHTS decreased the anti-apoptotic protein Bcl-xL level and increased the loss of mitochondria membrane potential and the amount of cytochrome c released. Moreover, DHTS activated caspase-9, caspase-3, and caspase-7 and caused cell apoptosis. The fact that DHTS-induced apoptosis could be blocked by pretreating cells with pan-caspase inhibitor confirmed that it is mediated through activation of the caspase-3-dependent pathway. In a nude mice xenograft experiment, DHTS significantly inhibited the tumor growth of MDA-MB-231 cells. Taken together, these results suggest that DHTS can inhibit human breast cancer cell proliferation and tumor growth, and might have potential chemotherapeutic applications.
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PMID:Anti-tumor potential of 15,16-dihydrotanshinone I against breast adenocarcinoma through inducing G1 arrest and apoptosis. 1786 26

Our recent study demonstrated that a novel proteasome inhibitor NPI-0052 triggers apoptosis in multiple myeloma (MM) cells, and importantly, that is distinct from bortezomib (Velcade) in its chemical structure, effects on proteasome activities, and mechanisms of action. Here, we demonstrate that combining NPI-0052 and bortezomb induces synergistic anti-MM activity both in vitro using MM cell lines or patient CD138(+) MM cells and in vivo in a human plasmacytoma xenograft mouse model. NPI-0052 plus bortezomib-induced synergistic apoptosis is associated with: (1) activation of caspase-8, caspase-9, caspase-3, and PARP; (2) induction of endoplasmic reticulum (ER) stress response and JNK; (3) inhibition of migration of MM cells and angiogenesis; (4) suppression of chymotrypsin-like (CT-L), caspase-like (C-L), and trypsin-like (T-L) proteolytic activities; and (5) blockade of NF-kappaB signaling. Studies in a xenograft model show that low dose combination of NPI-0052 and bortezomib is well tolerated and triggers synergistic inhibition of tumor growth and CT-L, C-L, and T-L proteasome activities in tumor cells. Immununostaining of MM tumors from NPI-0052 plus bortezomib-treated mice showed growth inhibition, apoptosis, and a decrease in associated angiogenesis. Taken together, our study provides the preclinical rationale for clinical protocols evaluating bortezomib together with NPI-0052 to improve patient outcome in MM.
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PMID:Combination of proteasome inhibitors bortezomib and NPI-0052 trigger in vivo synergistic cytotoxicity in multiple myeloma. 1800 97

The present study investigated the effect of YC-1, a novel anti-cancer agent, on the chemo-sensitivity of hepatocellular carcinoma (HCC). YC-1 was administered with chemo-cytotoxic drug, cisplatin, both in vitro and in vivo. YC-1 alone downregulated the expression of phosphorylated form of signal transducers and activators of transcription 3 (P-Stat3[705]), a key mediator in chemo-resistance. When combined with cisplatin, YC-1 further promoted tumor cell apoptosis, decreased the expression of P-Stat3(705), Bcl-xL, CyclinD1 and survivin, and induced the cleavage of caspase 9 and PARP. Overexpression of Stat3 reversed YC-1 induced cell death. YC-1 inhibited Stat3 activity by enhancing the polyubiquitination of P-Stat3(705) induced by cisplatin. In the in vivo setting, YC-1 combined with cisplatin remarkably suppressed tumor growth in a HCC xenograft model, and this effect was also accompanied by YC-1 mediated downregulation of P-Stat3(705), Bcl-xL, Cyclin D1 and survivin, and induction of cleaved caspase 9 and PARP in the tumor tissues. In conclusion, the present study demonstrated a novel anti-cancer effect of YC-1 in enhancing chemo-sensitivity of HCC cells to cisplatin through a Stat3 dependent manner. This finding provides insight into design of a new therapeutic strategy to improve efficacy of chemotherapy in HCC patients.
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PMID:Inhibition of Stat3 activity by YC-1 enhances chemo-sensitivity in hepatocellular carcinoma. 1805 67

Mitotic kinesins represent potential drug targets for anticancer chemotherapy. Inhibitors of different chemical classes have been identified that target human Eg5, a kinesin responsible for the establishment of the bipolar spindle. One potent Eg5 inhibitor is S-trityl-L-cysteine (STLC), which arrests cells in mitosis and exhibits tumor growth inhibition activity. However, the underlying mechanism of STLC action on the molecular level is unknown. Here, cells treated with STLC were blocked in mitosis through activation of the spindle assembly checkpoint as shown by the phosphorylated state of BubR1 and the accumulation of mitosis specific phosphorylation on histone H3 and aurora A kinase. Using live cell imaging, we observed prolonged mitotic arrest and subsequent cell death after incubation of GFP-alpha-tubulin HeLa cells with STLC. Activated caspase-9 occurred before cleavage of caspase-8 leading to the accumulation of the activated executioner caspase-3 suggesting that STLC induces apoptosis through the intrinsic apoptotic pathway. Proteome analysis following STLC treatment revealed 33 differentially regulated proteins of various cellular processes, 31 of which can be linked to apoptotic cell death. Interestingly, four identified proteins, chromobox protein homolog, RNA-binding Src associated in mitosis 68 kDa protein, stathmin, and translationally controlled tumor protein can be linked to mitotic and apoptotic processes.
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PMID:Proteome analysis of apoptosis signaling by S-trityl-L-cysteine, a potent reversible inhibitor of human mitotic kinesin Eg5. 1818 19

Molecular mechanisms responsible for lymphoma resistance to apoptosis often involve the bcl-2 pathway. In this study, we investigated the cell signaling pathways activated in bcl-2-overexpressing human mantle cell lymphoma cell lines (JVM-2 and Z-138) that have been treated with oblimersen, a molecular gene silencing strategy that effectively suppresses bcl-2 in vitro and in vivo. Z-138 cells expressed higher levels of bcl-2 and were more sensitive to the effects of bcl-2 silencing, mediated by oblimersen or bcl-2 small interfering RNA, in vitro. Tumors derived following injection of Z-138 cells were sensitive to oblimersen as judged by decreases in tumor growth rate and decreases in cell proliferation (as measured by Ki-67). Immunohistochemistry and Western blot analysis of oblimersen-treated Z-138 tumors revealed a dose-dependent decrease in bcl-2 levels and an associated increase in the proapoptotic proteins caspase-3 and caspase-9. Silencing bcl-2 in Z-138 xenografts revealed an associated dose-dependent suppression of bax, a decrease in nuclear factor-kappaB and phospho-nuclear factor-kappaB, and transient loss of p53 levels. Coimmunoprecipitation studies suggest that the latter observation is mediated by an association between bcl-2 and phospho-mdm2. Bcl-2 silencing also led to p27 down-regulation and coimmunoprecipitation studies point to a role for bcl-2 in regulation of p27 localization/degradation. Bcl-2 silencing was also correlated with loss of cyclin D1a protein levels but not cyclin D1b levels. Coimmunoprecipitation studies indicate that bcl-2 may mediate its effects on cyclin D1a via interaction with p38 mitogen-activated protein kinase as well as a previously unreported interaction between bcl-2 and cyclin D1a.
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PMID:Silencing Bcl-2 in models of mantle cell lymphoma is associated with decreases in cyclin D1, nuclear factor-kappaB, p53, bax, and p27 levels. 1837 22

Angiotensin II (Ang II) stimulates tumor growth and angiogenesis in some solid cancer cells, but its anti-apoptosis role in breast cancer remains unclear. To address this issue, we investigated the effect of Ang II on adriamycin-induced apoptosis in breast cancer MCF-7 cells. Treatment of human breast cancer MCF-7 cells with adriamycin, a DNA topoisomerase II alpha inhibitor, caused apoptosis. However, cells pretreated with Ang II were resistant to this apoptosis. Ang II significantly reduced the ratio of apoptotic cells and stimulation of phospho-Akt-Thr308 and phospho-Akt-Ser473 in a dose-dependent and time-dependent manner. In addition, Ang II significantly prevented apoptosis through inhibiting the cleavage of procaspase-9, a major downstream effector of Akt. The Ang II type 1 receptor (AT1R) was responsible for these effects. Among the signaling molecules downstream of AT1R, we revealed that the phosphatidylinositol 3-kinase/Akt pathway plays a predominant role in the anti-apoptotic effect of Ang II. Our data indicated that Ang II plays a critical anti-apoptotic role in breast cancer cells by a mechanism involving AT1R/phosphatidylinositol 3-kinase/Akt activation and the subsequent suppression of caspase-9 activation.
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PMID:Angiotensin II suppresses adriamycin-induced apoptosis through activation of phosphatidylinositol 3-kinase/Akt signaling in human breast cancer cells. 1840 28

Antiangiogenic therapies have shown varying results partly because each tumor type secretes a distinct panel of angiogenic factors to sustain its own microvascular network. In addition, recent evidence demonstrated that tumors develop resistance to antiangiogenic therapy by turning on alternate angiogenic pathways when one pathway is therapeutically inhibited. Here, we test the hypothesis that expression of a caspase-based artificial death switch in tumor-associated endothelial cells will disrupt tumor blood vessels and slow down tumor progression irrespective of tumor type. Adenoviral vectors expressing inducible Caspase-9 (iCaspase-9) under transcriptional regulation with the endothelial cell-specific vascular endothelial growth factor receptor-2 (VEGFR2) promoter (Ad-hVEGFR2-iCaspase-9) induced apoptosis of proliferating human dermal microvascular endothelial cells (HDMECs), but not human tumor cells (UM-SCC-17B, head and neck squamous cell carcinoma; HepG2, hepatocellular carcinoma; PC-3, prostate adenocarcinoma; SLK, Kaposi's sarcoma; MCF-7, breast adenocarcinoma). Notably, apoptosis was dependent upon activation of iCaspase-9 with the dimerizer drug AP20187. Local delivery of Ad-hVEGFR2-iCaspase-9 followed by intraperitoneal injection of AP20187 ablated tumor microvessels and inhibited xenografted tumor growth in all tumor models evaluated here. We conclude that a cancer gene therapy strategy based on a transcriptionally targeted viral vector expressing an inducible caspase allows for selective and controlled ablation of microvessels of histopathologically diverse tumor types.
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PMID:Cancer gene therapy with iCaspase-9 transcriptionally targeted to tumor endothelial cells. 1856 14

The unresponsiveness of metastatic melanoma to conventional chemotherapeutic and biological agents is largely due to the development of resistance to apoptosis. Pyrimethamine belongs to the group of antifolate drugs, and in addition to antiprotozoan effects, it exerts a strong proapoptotic activity, which we recently characterized in human T lymphocytes. However, no data regarding pyrimethamine anticancer activity are available thus far. To this end, we examined the in vitro effects of pyrimethamine on apoptosis, cell cycle distribution, and cell proliferation of human metastatic melanoma cell lines. The in vivo antitumor potential of pyrimethamine was evaluated in a severe combined immunodeficiency (SCID) mouse xenotransplantation model. Our data indicate that pyrimethamine, when used at a clinically relevant concentration, induced apoptosis in metastatic melanoma cells via the activation of the cathepsin B and the caspase cascade (i.e., caspase-8 and caspase-9) and subsequent mitochondrial depolarization. This occurred independently from CD95/Fas engagement. Moreover, pyrimethamine induced a marked inhibition of cell growth and an S-phase cell cycle arrest. Results obtained in SCID mice, injected s.c. with metastatic melanoma cells and treated with pyrimethamine, indicated a significant inhibitory effect on tumor growth. In conclusion, our results suggest that pyrimethamine-induced apoptosis may be considered as a multifaceted process, in which different inducers or regulators of apoptosis are simultaneously implicated, thus permitting death defects of melanoma cells to be bypassed or overcome. On these bases, we hypothesize that pyrimethamine could represent an interesting candidate for the treatment of metastatic melanoma.
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PMID:Pyrimethamine induces apoptosis of melanoma cells via a caspase and cathepsin double-edged mechanism. 1859 30

Nasopharyngeal carcinoma (NPC) is a common malignant tumor in South China. It has been reported that overexpression of antiapoptotic Bcl-2 family proteins in NPC has caused the lack of long-term efficacy of conventional therapies. Apogossypolone (ApoG2), a novel small-molecule inhibitor of antiapoptotic Bcl-2 family proteins, has been discovered as the optimized derivative of gossypol. In this study, we found that in NPC cells, ApoG2 totally blocked the antiapoptotic function of Bcl-2 family proteins without affecting the expression levels of these proteins. ApoG2 selectively inhibited proliferation of 3 NPC cell lines (C666-1, CNE-1 and CNE-2) that highly expressed the antiapoptotic Bcl-2 proteins. This inhibitory activity was associated with release of cytochrome c, activation of caspase-9 and caspase-3 and apoptosis of sensitive NPC cells. However, ApoG2 had no obvious inhibitory effect on NPC cell line HONE-1, which expressed antiapoptotic Bcl-2 and Bcl-xL at a low level. We further found that ApoG2 effectively suppressed tumor growth of NPC xenografts in nude mice and enhanced the antitumor effect of CDDP (cisplatin) on NPC cells in vitro and in vivo. Immunohistochemical results showed that the expression of CD31 decreased after ApoG2 treatment, which suggested inhibition of angiogenesis in NPC xenografts. Our findings strongly suggest that ApoG2 may serve as a novel inhibitor of Bcl-2 family proteins and, by targeting these proteins, may become a promising drug for the treatment of NPC.
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PMID:ApoG2, a novel inhibitor of antiapoptotic Bcl-2 family proteins, induces apoptosis and suppresses tumor growth in nasopharyngeal carcinoma xenografts. 1871 28

Apogossypolone (ApoG2) is a semi-synthesized derivative of gossypol. The principal objective of this study was to compare stability and toxicity between ApoG2 and gossypol, and to evaluate anti-lymphoma activity of ApoG2 in vitro and in vivo. ApoG2 shows better stability when compared with a racemic gossypol and can be better tolerated by mice compared to gossypol. ApoG2 showed significant inhibition of cell proliferation of WSU-DLCL(2) and primary cells obtained from lymphoma patients, whereas it displayed no toxicity on normal peripheral blood lymphocytes. For a treatment of 72 h, the IC(50) of ApoG2 was determined to be 350 nM against WSU-DLCL2 cells. Treatment with ApoG2 at 600 mg/kg resulted in significant growth inhibition of WSU-DLCL(2) xenografts. When combined with CHOP, ApoG2 displayed even more complete inhibition of tumor growth. ApoG2 binds to purified recombinant Bcl-2, Mcl-1 and Bcl-X(L) proteins with high affinity and is shown to block the formation of heterodimers between Bcl-X(L) and Bim. For a treatment of 72 h, ApoG2 induced a maximum of 32% of apoptotic cell death. Western blot experiments showed that treatment with ApoG2 led to cleavage of caspase-3, caspase-9 and PARP. Moreover, pretreatment of DLCL(2) cells with caspase-3, -9 and broad spectrum caspase inhibitors significantly blocked growth inhibition induced by ApoG2. In conclusion, ApoG2 effectively inhibits growth of DLCL(2) cells at least partly by inducing apoptosis. It is an attractive small molecule inhibitor of the Bcl-2 family proteins to be developed further for the treatment of diffuse large cell lymphoma.
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PMID:Apogossypolone, a nonpeptidic small molecule inhibitor targeting Bcl-2 family proteins, effectively inhibits growth of diffuse large cell lymphoma cells in vitro and in vivo. 1876 31


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