UMLS:C1140680 - FACTA Search

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Query: UMLS:C1140680 (ovarian cancer)
28,141 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Paclitaxel (Taxol) is a novel anti-cancer drug that has shown efficacy toward several malignant tumors, particularly ovarian tumors. We reported previously that paclitaxel can induce interleukin (IL)-8 promoter activation in subgroups of ovarian cancer through the activation of both AP-1 and nuclear factor kappaB. Further analysis of paclitaxel analogs indicates that the degree of IL-8 induction by analysis correlates with the extent of cell death; however, IL-8 itself is not the cause of cell death. This suggests that pathways that lead to IL-8 and cell death may overlap, although IL-8 per se does not kill tumor cells. To decipher the upstream signals for paclitaxel-induced transcriptional activation and cell death, we studied the involvement of protein kinases that lead to the activation of AP-1, specifically the c-Jun NH2-terminal kinase (JNK1), p38, and the extracellular signal-regulated kinase 1 (ERK1). The role of IkappaB in paclitaxel-induced cell death was also analyzed. Paclitaxel activated JNK, and to a lesser degree p38, but not ERK1. Paclitaxel-induced IL-8 promoter activation was inhibited by dominant-inhibitory mutants of JNK, p38, and the super-repressor form of IkappaBalpha, but not by dominant-inhibitory forms of ERK1. Dominant-inhibitory mutants of JNK1 also greatly reduced paclitaxel-induced cell death, and the kinetics of JNK induction was closely followed by DNA fragmentation. These results indicate (i) that paclitaxel activates the JNK signaling pathway and (ii) that JNK activation is a common point of paclitaxel-induced gene induction and cell death.
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PMID:Paclitaxel (Taxol)-induced gene expression and cell death are both mediated by the activation of c-Jun NH2-terminal kinase (JNK/SAPK). 977 47

Gonadotropin-releasing hormone (GnRH) receptor is present in 80% of ovarian cancer, and numerous studies have provided evidence for a role of GnRH in cell proliferation. In this study, the effect of GnRH on the invasion potential of ovarian cancer cells was investigated. In vitro migration and cell invasion assays with the ovarian cancer cell lines Caov-3 and OVCAR-3 revealed the biphasic nature of GnRH; low concentrations of GnRH agonist (GnRHa) increased the cell motility and invasiveness of these cells, but at increased concentrations, the stimulatory effect was insignificant. Reverse transcription-PCR, Western blot, and gelatin zymography showed that the expression of metastasis-related proteinases, matrix metalloproteinase (MMP)-2 and MMP-9, was up-regulated and activated by GnRHa. Moreover, we observed that GnRHa was able to transactivate the MMP-2 and MMP-9 promoters. The invasive/migratory phenotype activated by GnRHa can be blocked by specific inhibitors or neutralizing antibodies to MMP-2 and MMP-9. Knockdown of the GnRH receptor using small interfering RNA significantly inhibited the GnRH-induced MMP activation, invasion, and migration. In addition, we showed that the c-Jun NH(2)-terminal kinase, but not extracellular signal-regulated kinase 1/2 or p38 mitogen-activated protein kinase, signaling pathway was critical for GnRH-mediated up-regulation of MMP, cell invasion, and motility. These results indicate for the first time an expanded role for GnRH in other aspects of ovarian tumor progression, such as metastasis, via activation of MMP and the subsequent increase in cell migration and invasion.
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PMID:Gonadotropin-releasing hormone promotes ovarian cancer cell invasiveness through c-Jun NH2-terminal kinase-mediated activation of matrix metalloproteinase (MMP)-2 and MMP-9. 1710 27

Pertuzumab (Omnitarg, rhuMab 2C4) is a humanized monoclonal antibody, which inhibits HER2 dimerization. Because it has shown some clinical activity in ovarian cancer, this study sought to identify predictors of response to this agent in a model of ovarian cancer. A panel of 13 ovarian cancer cell lines was treated with heregulin beta1 (HRGbeta1) or transforming growth factor-alpha, and cell proliferation was assessed. Both agents increased cell number in the majority of cell lines studied, the response to both being similar (r = 0.83; P = 0.0004, Pearson test). HRGbeta1 stimulation could be partially reversed by pertuzumab in 6 of 13 cell lines, with complete reversal in PE04 and PE06 cells. Addition of pertuzumab to transforming growth factor-alpha-stimulated cells produced growth inhibition in 3 of 13 cell lines (PE01, PE04, and PE06). The magnitude of HRGbeta1-driven growth stimulation correlated significantly with an increase in extracellular signal-regulated kinase 2 (P = 0.037) but not Akt (P = 0.99) phosphorylation. Such HRGbeta1-driven phosphorylation of extracellular signal-regulated kinase 1/2 and Akt could be reduced with pertuzumab, accompanied by changes in cell cycle distribution. In cell lines responsive to pertuzumab, HRGbeta1-enhanced phosphorylation of HER2 (Tyr(877)) was reduced. Estrogen-stimulated changes in growth, cell cycle distribution, and signaling were reversed by pertuzumab, indicating cross-talk between HER2 and estrogen signaling. These data indicate that there is a subset of ovarian cancer cell lines sensitive to pertuzumab and suggest possible predictors of response to identify patients who could benefit from this therapy. Furthermore, we have identified an interaction between HER2 and estrogen signaling in this disease.
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PMID:Sensitivity to pertuzumab (2C4) in ovarian cancer models: cross-talk with estrogen receptor signaling. 1723 69

Ovarian cancer is the primary cause of death from gynecological malignancies with a poor prognosis characterized by widespread peritoneal dissemination. However, mechanisms of invasion and metastasis in ovarian cancer remain poorly understood. Epidermal growth factor (EGF) and hepatocyte growth factor (HGF) are often both overexpressed and contribute to the growth of ovarian cancer by activating autocrine pathways. In the present study, we investigated the mechanisms of invasive activity of EGF, HGF, and their synergistic effects in human ovarian cancer cells. Here our data suggest that EGF and HGF may use unique and overlapping signaling cascades leading to the invasive phenotype. We revealed that HGF-mediated cell migration and invasion required the coordinate activation of the phosphatidylinositol 3-kinase/Akt and extracellular signal-regulated kinase 1/2. Although EGF-dependent invasive phenotype appeared to have similar requirements for phosphatidylinositol 3-kinase, this growth factor used the alternative p38 MAPK pathway for cell invasion. A significant role of p38 MAPK was further supported by the observation that expression of dominant negative p38 MAPK likewise inhibited EGF-dependent invasiveness and cell motility. We also showed that EGF cooperated with HGF to promote a highly invasive phenotype via the increased secretion of matrix metalloproteinase (MMP)-9. The coincident induction of MMP-9 was functionally significant because inclusion of MMP-9 inhibitor or an anti-MMP-9 neutralizing antibody abolished EGF- and HGF-induced cellular invasion. These findings provide insights into the mechanism of the malignant progression of ovarian cancer.
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PMID:Synergistic effects of epidermal growth factor and hepatocyte growth factor on human ovarian cancer cell invasion and migration: role of extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase. 1767 18

Chemoresistance and therapeutic selectivity are major obstacles to successful chemotherapy of ovarian cancer. Manganese superoxide disumutase (MnSOD) is an important antioxidant enzyme responsible for the elimination of superoxide radicals. We reported here that MnSOD was significantly elevated in ovarian cancer cells and its overexpression was one of the mechanisms that increased resistance to apoptosis in cancer cells. Knockdown of MnSOD by small-interfering RNA (siRNA) led to an increase in superoxide generation and sensitisation of ovarian cancer cells to the two front-line anti-cancer agents doxorubicin and paclitaxel whose action involved free-radical generation. This synergistic effect was not observed in non-transformed ovarian surface epithelial cells. Furthermore, our results revealed that this combination at the cellular level augmented activation of caspase-3 and caspase-9, but not caspase-8, suggesting involvement of an intrinsic apoptotic pathway. Evaluation of signalling pathways showed that MnSOD siRNA enhanced doxorubicin- and paclitaxel-induced phosphorylation of extracellular signal-regulated kinase 1/2. Akt activation was not affected. These results identify a novel chemoresistance mechanism in ovarian cancer, and show that combination of drugs capable of suppressing MnSOD with conventional chemotherapeutic agents may provide a novel strategy with a superior therapeutic index and advantage for the treatment of refractory ovarian cancer.
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PMID:Chemosensitisation by manganese superoxide dismutase inhibition is caspase-9 dependent and involves extracellular signal-regulated kinase 1/2. 1859 23

3'-Phosphoinositide-dependent kinase-1 (PDK1) has been identified for its ability to phosphorylate and activate Akt. Accumulated studies have shown that the activation of the PDK1/Akt pathway plays a pivotal role in cell survival, proliferation, and tumorigenesis. Therefore, the PDK1/Akt pathway is believed to be a critical target for cancer intervention. In this paper, we report the discovery of a new function of phenothiazines, widely known as antipsychotics, inhibiting PDK1/Akt pathway. Upon epidermal growth factor (EGF) stimulation, phenothiazines specifically suppressed the kinase activity of PDK1 and the phosphorylation level of Akt. The inhibition of PDK1/Akt kinase resulted in suppression of EGF-induced cell growth and induction of apoptosis in human ovary cancer cells. In particular, phenothiazines were highly selective for downstream targets of PDK1/Akt and did not inhibit the activation of phosphatidylinositol 3-kinase (PI3K), EGFR, or extracellular signal-regulated kinase 1/2 (ERK1/2). In particular, phenothiazines effectively suppressed tumor growth in nude mice of human cancer cells. Taken together, these findings provide strong evidence for novel function of phenothiazines, pharmacologically targeting PDK1/Akt for anticancer drug discovery.
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PMID:Potential inhibition of PDK1/Akt signaling by phenothiazines suppresses cancer cell proliferation and survival. 1883 15

New cytotoxic agents are urgently needed for the treatment of advanced ovarian cancer because of the poor long-term response of this disease to conventional chemotherapy. Curcumin, obtained from the rhizome of Curcuma longa, has potent anticancer activity; however, the mechanism of curcumin-induced cytotoxicity in ovarian cancer cells remains a mystery. In this study we show that curcumin exhibited time- and dose-dependent cytotoxicity against monolayer cultures of ovarian carcinoma cell lines with differing p53 status (wild-type p53: HEY, OVCA429; mutant p53: OCC1; null p53: SKOV3). In addition, p53 knockdown or p53 inhibition did not diminish curcumin killing of HEY cells, confirming p53-independent cytotoxicity. Curcumin also killed OVCA429, and SKOV3 cells grown as multicellular spheroids. Nuclear condensation and fragmentation, as well as DNA fragmentation and poly (ADP-ribose) polymerase-1 cleavage in curcumin-treated HEY cells, indicated cell death by apoptosis. Procaspase-3, procaspase-8, and procaspase-9 cleavage, in addition to cytochrome c release and Bid cleavage into truncated Bid, revealed that curcumin activated both the extrinsic and intrinsic pathways of apoptosis. Bax expression was unchanged but Bcl-2, survivin, phosphorylated Akt (on serine 473), and total Akt were downregulated in curcumin-treated HEY cells. Curcumin also activated p38 mitogen-activated protein kinase (MAPK) without altering extracellular signal-regulated kinase 1/2 activity. We conclude that p53-independent curcumin-induced apoptosis in ovarian carcinoma cells involves p38 MAPK activation, ablation of prosurvival Akt signaling, and reduced expression of the antiapoptotic proteins Bcl-2 and survivin. These data provide a mechanistic rationale for the potential use of curcumin in the treatment of ovarian cancer.
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PMID:Curcumin-induced apoptosis in ovarian carcinoma cells is p53-independent and involves p38 mitogen-activated protein kinase activation and downregulation of Bcl-2 and survivin expression and Akt signaling. 1967 5

New strategies in the therapy for malignant diseases depend on a targeted influence on signal transduction pathways that regulate proliferation, cell growth, differentiation, and apoptosis by the activation of serine/threonine kinases. Enzastaurin (LY317615.HCl), a selective inhibitor of protein kinase Cbeta (PKCbeta), is one of these new drugs and causes inhibition of proliferation and induction of apoptosis. Pemetrexed, a multitarget inhibitor of folate pathways, is broadly active in a wide variety of solid tumors. Therefore, the effect of enzastaurin and the combination treatment with pemetrexed was analyzed when applied to the drug-sensitive ovarian cancer cell line HEY and various subclones with drug resistance against cisplatin, etoposide, docetaxel, and paclitaxel, as well as pemetrexed, and gemcitabine. In these novel chemoresistant subclones, the expression of the enzastaurin targets PKCbetaII and glycogen synthase kinase 3beta (GSK3beta) was analyzed. Exposition to enzastaurin showed various inhibitory effects on phosphorylated forms of GSK3beta and the mitogen-activated protein kinase extracellular signal-regulated kinase 1/2. Cell proliferation experiments identified the cell line-specific half-maximal inhibitory concentration values of enzastaurin and a synergistic inhibitory effect by cotreatment with the antifolate pemetrexed. Induction of apoptosis by enzastaurin treatment was investigated by Cell Death Detection ELISA and immunoblot analyses. Simultaneous treatment with pemetrexed resulted in an enhanced inhibition of proliferation and induction of apoptosis even in partial enzastaurin-resistant cells. Therefore, the combinational effect of enzastaurin and pemetrexed can have promise in clinical application to overcome the fast-growing development of resistance to chemotherapy in ovarian cancer.
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PMID:Combination of enzastaurin and pemetrexed inhibits cell growth and induces apoptosis of chemoresistant ovarian cancer cells regulating extracellular signal-regulated kinase 1/2 phosphorylation. 1970 1

The gonadotropin hypothesis proposes that elevated serum gonadotropin levels may increase the risk of epithelial ovarian cancer (EOC). We have studied the effect of treating EOC cell lines (OV207 and OVCAR-3) with FSH or LH. Both gonadotropins activated the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (ERK1/2) pathway and increased cell migration that was inhibited by the MAPK 1 inhibitor PD98059. Both extra- and intracellular calcium ion signalling were implicated in gonadotropin-induced ERK1/2 activation as treatment with either the calcium chelator EGTA or an inhibitor of intracellular calcium release, dantrolene, inhibited gonadotropin-induced ERK1/2 activation. Verapamil was also inhibitory, indicating that gonadotropins activate calcium influx via L-type voltage-dependent calcium channels. The cAMP/protein kinase A (PKA) pathway was not involved in the mediation of gonadotropin action in these cells as gonadotropins did not increase intracellular cAMP formation and inhibition of PKA did not affect gonadotropin-induced phosphorylation of ERK1/2. Activation of ERK1/2 was inhibited by the protein kinase C (PKC) inhibitor GF 109203X as well as by the PKCdelta inhibitor rottlerin, and downregulation of PKCdelta was inhibited by small interfering RNA (siRNA), highlighting the importance of PKCdelta in the gonadotropin signalling cascade. Furthermore, in addition to inhibition by PD98059, gonadotropin-induced ovarian cancer cell migration was also inhibited by verapamil, GF 109203X and rottlerin. Similarly, gonadotropin-induced proliferation was inhibited by PD98059, verapamil, GF 109203X and PKCdelta siRNA. Taken together, these results demonstrate that gonadotropins induce both ovarian cancer cell migration and proliferation by activation of ERK1/2 signalling in a calcium- and PKCdelta-dependent manner.
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PMID:Gonadotropin-induced ovarian cancer cell migration and proliferation require extracellular signal-regulated kinase 1/2 activation regulated by calcium and protein kinase C{delta}. 2021 2

The chemokine CXCL1 is elevated in plasma and ascites from patients with ovarian cancer. We have previously shown that CXCL1 is a marker of phosphatidylinositol 3-kinase signalling in epithelial ovarian cancer (EOC) cell lines, a pathway that is commonly activated in ovarian tumours. To investigate whether CXCL1 also has functional significance in ovarian cancer, this chemokine was either down-regulated using siRNAs or overexpressed by transfection of CXCL1 into the EOC cell lines SKOV3 and OVCAR-3 and proliferation assessed over 7 days. Overexpression of CXCL1 increased proliferation of ovarian cancer cells over 7 days, while down-regulation was inhibitory. Treatment of cells with recombinant CXCL1 induced epidermal growth factor receptor (EGFR) phosphorylation at Y1068, indicating crosstalk between the CXCL1 G-protein-coupled receptor CXCR2 and the EGFR. CXCL1-induced proliferation was also decreased by inhibition of EGFR kinase activity and was dependent on extracellular matrix metalloproteinase-mediated release of heparin-binding EGF (HB-EGF). Involvement of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (ERK1/2) signalling was also evident since inhibition of both Ras and MEK activity decreased CXCL1-induced proliferation. CXCL1-induced ERK1/2 phosphorylation was inhibited by the MEK1 inhibitor PD98059; however, EGFR phosphorylation was unaffected, indicating that CXCL1 activation of MAPK signalling is downstream of the EGFR. Taken together, these data show that CXCL1 functions through CXCR2 to transactivate the EGFR by proteolytic cleavage of HB-EGF, leading to activation of MAPK signalling and increased proliferation of EOC cells.
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PMID:The chemokine CXCL1 induces proliferation in epithelial ovarian cancer cells by transactivation of the epidermal growth factor receptor. 2070 23

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