Human Epithelial Ovarian Cancer Research Articles

MiR-373 targeting of the Rab22a oncogene suppresses tumor invasion and metastasis in ovarian cancer.

Metastasis is major cause of mortality in patients with ovarian cancer. MiR-373 has been shown to play pivotal roles in tumorigenesis and metastasis; however, a role for miR-373 in ovarian cancer has not been investigated. In this study, we show that the miR-373 expression is down-regulated in human epithelial ovarian cancer (EOC) and inversely correlated with clinical stage and histological grade. Ectopic overexpression of miR-373 in human EOC cells suppressed cell invasion in vitro and metastasis in vivo, and the epithelial-mesenchymal transition process. Silencing the expression of miR-373 resulted in an increased migration and invasion of EOC cells. Using integrated bioinformatics analysis, gene expression arrays, and luciferase assay, we identified Rab22a as a direct and functional target of miR-373 in EOC cells. Expression levels of miR-373 were inversely correlated with Rab22a protein levels in human EOC tissues. Rab22a knockdown inhibited invasion and migration of EOC cells, increased E-cadherin expression, and suppressed the expression of N-cadherin. Moreover, overexpression of Rab22a abrogated miR-373-induced invasion and migration of EOC cells. Taken together, these results demonstrate that miR-373 suppresses EOC invasion and metastasis by directly targeting Rab22a gene, a new potential therapeutic target in EOC.

Effects of Treg cells and IDO on human epithelial ovarian cancer cells under hypoxic conditions.

The aim of the present study was to explore the effect of hypoxia on ovarian cancer. A total of 6 samples were analyzed: SKOV3-IP cells (ovarian cancer cell line); SKOV3-IP and regulatory T (Treg) cells; SKOV3-IP and cytotoxic T lymphocytes (CTLs); SKOV3-IP and natural killer (NK) cells; SKOV3-IP co-cultured with CTLs and Treg cells; and SKOV3-IP co-cultured with Treg cells and NK cells. The expression of indoleamine 2,3-dioxygenase (IDO) was detected by reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. An enzyme-linked immunosorbent assay (ELISA) was used to detect the concentration of transforming growth factor-β (TGF-β), interferon-γ (IFN-γ), interleukin-2 (IL-2), interleukin-10 (IL-10), and perforin. Moreover, ovarian cancer cell apoptosis and invasive ability were examined using flow cytometry and a Transwell chamber assay. IDO expression was significantly reduced in hypoxia and enhanced by Treg cells. Treg cells inhibited the IL-2, IFN-γ and perforin secretion, and significantly (P<0.05) increased the IL-10 and TGF-β levels. The effects of Treg cells were enhanced with prolongation of the cell exposure to hypoxic conditions. In addition, Treg cells attenuated the promotive effect of CTLs and NK cells on cancer cell apoptosis. In addition, Treg cells significantly increased the SKOV3-IP invasive ability (P=0.00109) under hypoxic conditions. Our results suggest that IDO and Treg cells may serve as important therapeutic targets for patients with ovarian cancer.

The marine-derived fungal metabolite, terrein, inhibits cell proliferation and induces cell cycle arrest in human ovarian cancer cells.

The difficulties faced in the effective treatment of ovarian cancer are multifactorial, but are mainly associated with relapse and drug resistance. Cancer stem-like cells have been reported to be an important contributor to these hindering factors. In this study, we aimed to investigate the anticancer activities of a bioactive fungal metabolite, namely terrein, against the human epithelial ovarian cancer cell line, SKOV3, primary human ovarian cancer cells and ovarian cancer stem-like cells. Terrein was separated and purified from the fermentation metabolites of the marine sponge-derived fungus, Aspergillus terreus strain PF26. Its anticancer activities against ovarian cancer cells were investigated by cell proliferation assay, cell migration assay, cell apoptosis and cell cycle assays. The ovarian cancer stem-like cells were enriched and cultured in a serum-free in vitro suspension system. Terrein inhibited the proliferation of the ovarian cancer cells by inducing G2/M phase cell cycle arrest. The underlying mechanisms involved the suppression of the expression of LIN28, an important marker gene of stemness in ovarian cancer stem cells. Of note, our study also demonstrated the ability of terrein to inhibit the proliferation of ovarian cancer stem-like cells, in which the expression of LIN28 was also downregulated. Our findings reveal that terrein (produced by fermention) may prove to be a promising drug candidate for the treatment of ovarian cancer by inhibiting the proliferation of cancer stem-like cells.

Deregulation of miR-128 in ovarian cancer promotes cisplatin resistance.

Platinum-based chemotherapy is the standard treatment in advanced ovarian cancer, but most patients will relapse with drug-resistant disease. MicroRNAs have been demonstrated to function in chemoresistance in cancers. In this study, we focused on the role of miR-128 in cisplatin-resistant ovarian cancer. The expression of miR-128 RNA and its targeted genes, the polycomb ring finger oncogene Bmi-1 and ATP-binding cassette subfamily C member 5 (ABCC5), were investigated in the epithelial ovarian cancer cells and ovarian carcinomas. miR-128 expression was significantly reduced in the cisplatin-resistant human epithelial ovarian cancer cell line SKOV3/CP compared with parental SKOV3 cells and decreased upon treatment with cisplatin in a concentration-dependent manner in SKOV3, OVCAR3, and PEO14 cells. Overexpression of miR-128 resensitized SKOV3/CP cells to cisplatin and reduced the expression of cisplatin-resistant-related proteins ABCC5 and Bmi-1, whereas miR-128 inhibitors increased cisplatin resistance in SKOV3 cells. Cisplatin combined with miR-128 agomirs inhibited the growth of SKOV3/CP xenograft tumors more effectively than cisplatin alone. Diminished expression of ABCC5 and Bmi-1 and higher cisplatin concentrations were observed in tumor tissue of mice treated with miR-128 agomirs in addition to cisplatin. Taken together, our findings suggest that miR-128 may act as a promising therapeutic target for improvement of tumor sensitivity to cisplatin.

Abstract 3144: PDZ-RhoGEF/β-arrestin-1 interaction mediates endothelin A receptor-induced RhoA activation and cell motility in ovarian tumor cells

Abstract β-arrestins (β-arrs), consisting of β-arr1 and β-arr2, are involved in G-protein-coupled receptor signaling, and guide the receptor signals in chemotaxis and cytoskeletal reorganization. Among them, receptor A for endothelin-1 (ET-1), namely ETAR, is overexpressed in epithelial ovarian cancer (EOC) and promote metastatic spread. We have recently reported that β-arr1 regulates ETAR-mediated β-catenin signaling to promote EOC cell invasion. Here we evaluated the effects of ET-1 on polarized cell migration correlating with the regulation of Rho-GTPase activity and its subsequent organization of the actin structures supporting migration and the involvement of β-arr1 in these effects. We show that, in EOC cells cultured on collagen type I, ET-1 promotes actin-based dynamic protrusion resembling to pseudopodia, containing β-arr-1. Furthermore, in a β-arr1/ETAR-dependent manner, ET-1 activates RhoA GTPase and downstream the dephosphorylation/activation of cofilin, as shown by pull down assay and immunoblotting analysis. The inhibitory effect of the Rho pathway inhibitor I, Y-27632, demontrates that RhoA GTPase is involved in ET-1-induced cell migration. By screening members of a Rho-guanine nucleotide exchange factor (Rho-GEF) family involved in RhoA activation, we found that PDZ-RhoGEF mRNA levels are highly expressed in EOC cells. Moreover, PDZ-RhoGEF is responsible for ET-1-induced RhoA activation through interaction with β-arr1, that in turn, promotes PDZ-RhoGEF tyrosine phosphorylation and activation. Depletion of PDZ-RhoGEF expression significantly impaired ET-1-stimulated migration of EOC cells, demonstrating that PDZ-RhoGEF/β-arrestin-1 interaction mediates ETAR-driven ovarian tumor cell motility through regulation of RhoA. Analysis of EOC human tissues revealed that PDZ-RhoGEF is overexpressed in human EOC tissues. Collectively, our data establish a novel role for β-arr1 and PDZ-RhoGEF as regulator of ET-1-induced EOC cell migration, unraveling new components required for tumor progression. Supported by AIRC. Citation Format: Piera Tocci, Roberta Cianfrocca, Elisa Semprucci, Valeriana Di Castro, Anna Bagnato, Laura Rosanò. PDZ-RhoGEF/β-arrestin-1 interaction mediates endothelin A receptor-induced RhoA activation and cell motility in ovarian tumor cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3144. doi:10.1158/1538-7445.AM2014-3144

Abstract 5452: Whole transcriptome analysis of ovarian cancer cells reveals the mechanism of action for a potent organometallic anticancer agent

Abstract Introduction. Ovarian cancer is a diverse disease and remains one of the most difficult-to-treat cancers, with over 70% of epithelial ovarian cancers (EOC) not diagnosed until late stage. Platinum anticancer agents are often used as first-line treatments for EOC, however, patient relapse and subsequent platinum resistance present clinical problems. New metal-based chemotherapeutics, which are equally, or more potent in EOC and platinum resistant EOC show promise as effective second-line treatments. Complex 1 ([Os(η6-p-cym)(NMe2-azpy)I]+) is an osmium-based organometallic agent, with equipotent activity in A2780 human EOC cells and their cisplatin-resistant counterpart, A2780cis [1]. Although highly active in vitro and in vivo, the mechanism of action (MOA) of complex 1 is unknown [2]. Results &amp; Discussion. We perform whole transcriptome analysis for A2780 cells exposed to 1 over a 48 h time course, using RNAseq. The estimated chromosome-wide expression across the time series reveals a majority number of mapped reads to the mitochondrial chromosome, with differential mapping between control and treated cells. Assessing the number of differentially expressed genes (DEGs) between control and treated cells, shows a rapid cellular response after 4 h and the highest number of DEGs at 48 h. Analysis of all DEGs using pathway analysis provides insights into cellular response across the time series. After 24 h, the NRF2 oxidative stress response pathway is most significantly involved in cellular response, although key components in this pathway are active after just 4 h. This pathway is linked to the production of reactive oxygen species (ROS) by the mitochondria, activating downstream antioxidant proteins and increasing cellular levels of GSH. High levels of ROS were detected by flow cytometry, and interestingly when cells are co-incubated with a GSH inhibitor, there is a dramatic decrease in IC50 and increase in ROS [3]. Cell viability assays suggest that cell death is activated between 24 and 72 h exposure, down-regulation of apoptotic caspases suggests cell death does not proceed through a normal apoptotic process. Caspase-1, which activates pro-interleukins to elicit an immune response, is differentially up-regulated throughout the time series. This caspase is closely linked to cellular ROS and can activate an alternative mode of cell death, pyroptosis. Conclusions. We have elucidated the MOA of complex 1 through whole transcriptome analysis: cancer cell death through mitochondrial effects and production of ROS. Activation of non-apoptotic cell death can be beneficial as cancer cells often develop resistance mechanisms to evade apoptosis. [1] Fu, Y. et al. (2010) J. Med. Chem. 53: 8192-8196 [2] Shnyder, S. et al. (2011) Med. Chem. Comm. 2: 666-668 [3] Romero-Canelón, I. et al. (2013) Inorg. Chem. 52: 12276-12291 Citation Format: Jessica M. Hearn, Isolda Romero-Canelón, Fu Ying, David L. Wild, Peter J. Sadler. Whole transcriptome analysis of ovarian cancer cells reveals the mechanism of action for a potent organometallic anticancer agent. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5452. doi:10.1158/1538-7445.AM2014-5452

Withaferin a alone and in combination with cisplatin suppresses growth and metastasis of ovarian cancer by targeting putative cancer stem cells.

Currently, the treatment for ovarian cancer entails cytoreductive surgery followed by chemotherapy, mainly, carboplatin combined with paclitaxel. Although this regimen is initially effective in a high percentage of cases, unfortunately within few months of initial treatment, tumor relapse occurs because of platinum-resistance. This is attributed to chemo-resistance of cancer stem cells (CSCs). Herein we show for the first time that withaferin A (WFA), a bioactive compound isolated from the plant Withania somnifera, when used alone or in combination with cisplatin (CIS) targets putative CSCs. Treatment of nude mice bearing orthotopic ovarian tumors generated by injecting human ovarian epithelial cancer cell line (A2780) with WFA and cisplatin (WFA) alone or in combination resulted in a 70 to 80% reduction in tumor growth and complete inhibition of metastasis to other organs compared to untreated controls. Histochemical and Western blot analysis of the tumors revealed that inclusion of WFA (2 mg/kg) resulted in a highly significant elimination of cells expressing CSC markers - CD44, CD24, CD34, CD117 and Oct4 and downregulation of Notch1, Hes1 and Hey1 genes. In contrast treatment of mice with CIS alone (6 mg/kg) had opposite effect on those cells. Increase in cells expressing CSC markers and Notch1 signaling pathway in tumors exposed to CIS may explain recurrence of cancer in patients treated with carboplatin and paclitaxel. Since, WFA alone or in combination with CIS eliminates putative CSCs, we conclude that WFA in combination with CIS may present more efficacious therapy for ovarian cancer.

The functional proteomics analysis of VEGF-treated human epithelial ovarian cancer cells.

Vascular endothelial growth factor (VEGF), one of the most important angiogenic factor, can impact the tumor cell proliferation and invasion, but the mechanism remains unclear. This study is to investigate the key proteins which may play an important role in the VEGF-induced progress of ovarian cancer cells. The total protein from HO-8910 cells was separated by two-dimensional electrophoresis (2-DE), and differentially expressed proteins were identified by matrix-assisted laser desorption and ionization time-of-flight tandem mass spectrometry (MALDI-TOF MS) and PDQuest image analysis software. Furthermore, real-time PCR, Western blot, and immunocytochemistry were also used to confirm different expression levels of differential proteins. Morphological changes and invasion capability were evaluated by electron microscope and Matrigel invasion assay, respectively. The highly reproducible and well-resolved 2-DE patterns of both HO-8910/VEGF and HO-8910 cells were acquired. A total of 17 expressed differential proteins were identified, 8 proteins were upregulated (ACTB, TIM, PDIA3, PDIA1, DCTN2, KIC17, SIAS, and KIC10) and 9 downregulated (KIC18, GRP78, CAPG, PPIA, ROA2, LMNA, EZRI, ADRM1, and ENOA). Ultrastructure of VEGF-treated group showed more malignant characteristic compared with control group, an obvious increase in the number of cells penetrating the Matrigel membrane in VEGF-treated group (P < 0.05). These results suggested that VEGF could impact ovarian cancer's malignant progression by regulating expression of associated proteins.

Anoikis resistance is a critical feature of highly aggressive ovarian cancer cells.

High-grade serous ovarian cancer (HGS-OvCA) is an aggressive form of epithelial ovarian cancer (EOC), and accounts for the majority of deaths due to EOC. The critical cellular processes and underlying molecular mechanisms that define this malignancy remain poorly understood. Using a syngeneic murine model, we investigated the changes that accompanied the progression to increased aggressiveness induced by in vivo passage of mouse EOC cells. We found that enhanced anoikis resistance was a key cellular process associated with greater aggressiveness and tumorigenicity in vivo. Biochemical studies revealed that the enhanced anoikis resistance was associated with the activation of the Src/Akt/Erk signaling pathway. A higher rate of metabolism and autophagy were also associated with increased anoikis resistance. Blocking these pathways with specific inhibitors and/or genetic modifications significantly increased anoikis in vitro and inhibited tumor development in vivo. In addition, we demonstrated that similar signaling pathways were also involved in a human EOC cell line model. Collectively, our data suggest that anoikis resistance represents a critical and a distinguishing feature underlying the aggressiveness of ovarian cancer cells.

High expression of UCH37 is significantly associated with poor prognosis in human epithelial ovarian cancer.

Ubiquitin carboxyl-terminal hydrolase 37 (UCH37) is a member of deubiquitinating enzymes. It can suppress protein degradation through disassembling polyubiquitin from the distal subunit of the chain. The aim of this study was to assess the value of UCH37 in predicting tumor recurrence after curative resection in epithelial ovarian cancer (EOC) patients. In this study, the expression level of UCH37 in 5 paired EOC and normal tissue was tested by Western blot. And the association of UCH37 expression and prognostic value was analyzed in 100 tumor specimens from EOC patients, who underwent curative resection between 2003 and 2011. We found that UCH37 was up-regulated in most of the tumor tissue and high expression of UCH37 was an independent significant predictor associated with the poor outcome and recurrence of EOC (p=0.0037 and p=0.0042 in overall and disease-free survival, respectively), especially in the advanced stage of EOC (p=0.0106 and p=0.0115 in overall and disease-free survival, respectively), and may become a novel predictor for prognosis of EOC patients after curative resection. Our data suggest for the first time that UCH37 overexpression is associated with advanced tumor progression and poor clinical outcome of EOC patients and may help physicians make informed decisions regarding adjuvant treatment following curative resection.

Down-regulated aquaporin 5 inhibits proliferation and migration of human epithelial ovarian cancer 3AO cells.

BackgroundRecent studies suggested that aquaporins 5 (AQP5) was associated with many kinds of cancers and regulated many processes of various kinds of cancer cells. Our previous studies also demonstrated that AQP5 was highly expressed in epithelial ovarian cancer and contributed to the progress of ovarian cancer.MethodsLentivirus for knocking-down the expression of AQP5 was prepared and verified by qPCR and Western blotting. Cell counting kit-8 (CCK8) assay and transwell assay were performed to investigate the role of AQP5 on proliferation and migration of 3AO cells. The effects of down-regulating AQP5 on tumorigenesis were tested by tumor xenografts experiments.ResultsAn effective lentivirus silencing AQP5 expression was obtained and used in this study. Down-regulating AQP5 inhibited proliferation and migration of cultured human epithelial ovarian cancer 3AO Cell. Furthermore, interfering of AQP5 during tumorigenesis could efficiently decrease the tumor growth in athymic mice.ConclusionsThese findings altogether suggest that AQP5 regulated multi processes in ovarian carcinogenesis and may be an attractive therapeutic target.

Expression and immune responses to MAGE antigens predict survival in epithelial ovarian cancer.

The MAGE cancer-testis antigens (CTA) are attractive candidates for immunotherapy. The aim of this study was to determine the frequency of expression, humoral immunity and prognostic significance of MAGE CTA in human epithelial ovarian cancer (EOC). mRNA or protein expression frequencies were determined for MAGE-A1, -A3, -A4, -A10 and -C1 (CT7) in tissue samples obtained from 400 patients with EOC. The presence of autologous antibodies against the MAGE antigens was determined from 285 serum samples. The relationships between MAGE expression, humoral immunity to MAGE antigens, and clinico-pathologic characteristics were studied. The individual frequencies of expression were as follows: A1: 15% (42/281), A3: 36% (131/390), A4: 47% (186/399), A10: 52% (204/395), C1: 16% (42/267). Strong concordant expression was noted with MAGE-A1:–A4, MAGE-A1:–C1 and MAGE-A4:–A10 (p<0.0005). Expression of MAGE-A1 or -A10 antigens resulted in poor progression free survival (PFS) (OR 1.44, CI 1.01–2.04, p = 0.044 and OR 1.3, CI 1.03–1.64, p = 0.03, respectively); whereas, MAGE-C1 expression was associated with improved PFS (OR 0.62, CI 0.42–0.92, p = 0.016). The improved PFS observed for MAGE-C1 expression, was diminished by co-expression of MAGE-A1 or -A10. Spontaneous humoral immunity to the MAGE antigens was present in 9% (27/285) of patients, and this predicted poor overall survival (log-rank test p = 0.0137). These findings indicate that MAGE-A1, MAGE-A4, MAGE-A3, and MAGE-A10 are priority attractive targets for polyvalent immunotherapy in ovarian cancer patients.

MicroRNA-150 predicts a favorable prognosis in patients with epithelial ovarian cancer, and inhibits cell invasion and metastasis by suppressing transcriptional repressor ZEB1.

MicroRNA (miR)-150 has been reported to be dramatically downregulated in human epithelial ovarian cancer (EOC) tissues and patients’ serum compared to normal controls. This study aimed to investigate clinical significance and molecular mechanisms of miR-150 in EOC. In the current study, quantitative real-time PCR analysis showed that miR-150 was significantly downregulated in human EOC tissues compared to normal tissue samples. Then, we demonstrated the significant associations of miR-150 downregulation with aggressive clinicopathological features of EOC patients, including high clinical stage and pathological grade, and shorter overall and progression-free survivals. More importantly, the multivariate analysis identified miR-150 expression as an independent prognostic biomarker in EOC. After that, luciferase reporter assays demonstrated that Zinc Finger E-Box Binding Homeobox 1 (ZEB1), a crucial regulator of epithelial-to-mesenchymal transition (EMT), was a direct target of miR-150 in EOC cells. Moreover, we found that the ectopic expression of miR-150 could efficiently inhibit cell proliferation, invasion and metastasis by suppressing the expression of ZEB1. Furthermore, we also observed a significantly negative correlation between miR-150 and ZEB1 mRNA expression in EOC tissues (rs = –0.45, P<0.001). In conclusion, these findings offer the convincing evidence that aberrant expression of miR-150 may play a role in tumor progression and prognosis in patients with EOC. Moreover, our data reveal that miR-150 may function as a tumor suppressor and modulate EOC cell proliferation, and invasion by directly and negatively regulating ZEB1, implying the re-expression of miR-150 might be a potential therapeutic strategy for EOC.

Expression and functions of galectin-7 in ovarian cancer.

There is a critical need to develop effective new strategies for diagnosis and treatment of ovarian cancer. In the present work, we investigated the expression of galectin-7 (gal-7) in epithelial ovarian cancer (EOC) cells and studied its functional relevance. Immunohistochemical analysis of gal-7 expression in tissue microarrays showed that while gal-7 was not detected in normal ovarian tissues, positive cytoplasmic staining of gal-7 was detected in epithelial cells in all EOC histological subtypes but was more frequent in high grade tumors and metastatic samples. Gal-7 expression correlated with a significant difference in the overall survival of patients with ovarian serous cystadenocarcinoma. Furthermore, using human EOC cell lines, we found that gal-7 expression was induced by mutant p53. Mechanistically, Matrigel invasion assays and live cell imaging showed that gal-7 increased the invasive behavior of ovarian cancer cells by inducing MMP-9 and increasing cell motility. EOC cells can also secrete gal-7. Recombinant human gal-7 kills Jurkat T cells and human peripheral T cells, suggesting that gal-7 also has immunosuppressive properties. Taken together, our study validates the clinical significance of gal-7 overexpression in ovarian cancer and provides a rationale for targeting gal-7 to improve the outcome of patients with this disease.

Low Concentration of Quercetin Antagonizes the Cytotoxic Effects of Anti-Neoplastic Drugs in Ovarian Cancer

ObjectiveThe role of Quercetin in ovarian cancer treatment remains controversial, and the mechanism is unknown. The aim of this study was to investigate the therapeutic effects of Quercetin in combination with Cisplatin and other anti-neoplastic drugs in ovarian cancer cells both in vitro and in vivo, along with the molecular mechanism of action.MethodsQuercetin treatment at various concentrations was examined in combination with Cisplatin, taxol, Pirarubicin and 5-Fu in human epithelial ovarian cancer C13* and SKOV3 cells. CCK8 assay and Annexin V assay were for cell viability and apoptosis analysis, immunofluorescence assay, DCFDA staining and realtime PCR were used for reactive oxygen species (ROS)-induced injury detection and endogenous antioxidant enzymes expression. Athymic BALB/c-nu nude mice were injected with C13*cells to obtain a xenograft model for in vivo studies. Immunohistochemical analysis was carried out to evaluate the ROS-induced injury and SOD1 activity of xenograft tumors.ResultsContrary to the pro-apoptotic effect of high concentration (40 µM–100 µM) of Quercetin, low concentrations (5 µM–30 µM) of Quercetin resulted in varying degrees of attenuation of cytotoxicity of Cisplatin treatment when combined with Cisplatin. Similar anti-apoptotic effects were observed when Quercetin was combined with other anti-neoplastic agents: Taxol, Pirarubicin and 5-Fluorouracil (5-Fu). Low concentrations of Quercetin were observed to suppress ROS-induced injury, reduce intracellular ROS level and increase the expression of endogenous antioxidant enzymes, suggesting a ROS-mediated mechanism of attenuating anti-neoplastic drugs. In xenogeneic model, Quercetin led to a substantial reduction of therapeutic efficacy of Cisplatin along with enhancing the endogenous antioxidant enzyme expression and reducing ROS-induced damage in xenograft tumor tissue.ConclusionTaken together, these data suggest that Quercetin at low concentrations attenuate the therapeutic effects of Cisplatin and other anti-neoplastic drugs in ovarian cancer cells by reducing ROS damage. Quercetin supplementation during ovarian cancer treatment may detrimentally affect therapeutic response.

Clinicopathological and biological significance of aberrant activation of glycogen synthase kinase-3 in ovarian cancer.

BackgroundGlycogen synthase kinase-3 (GSK-3) plays an important role in human cancer. The aim of this study is to evaluate the clinicopathological significance of expression of GSK-3α/β and pGSK-3α/βTyr279/216 in patients with epithelial ovarian cancer and to investigate whether GSK-3 inhibition can influence cell viability and tumor growth of ovarian cancer.MethodsImmunohistochemistry was used to examine expression of GSK-3α/β and pGSK-3α/βTyr279/216 in 71 human epithelial ovarian cancer tissues and correlations between protein expression, and clinicopathological factors were analyzed. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay following exposure of ovarian carcinoma cells to pharmacological inhibitors of GSK-3 or GSK-3 small interfering RNA. In vivo validation of tumor growth inhibition was performed with xenograft mice.ResultsThe expression levels of GSK-3α/β and pGSK-3α/βTyr279/216 in ovarian cancers were significantly higher than those in benign tumors. High expression of GSK-3α/β was more likely to be found in patients with advanced International Federation of Gynecology and Obstetrics (FIGO) stages and high serum cancer antigen 125. Higher expression of pGSK-3α/βTyr279/216 was associated with advanced FIGO stages, residual tumor mass, high serum cancer antigen 125, and poor chemoresponse. Worse overall survival was revealed by Kaplan–Meier survival curves in patients with high expression of GSK-3α/β or pGSK-3α/βTyr279/216. Multivariate analysis indicated that FIGO stage, GSK-3α/β expression, and pGSK-3α/βTyr279/216 expression were independent prognostic factors for overall survival. GSK-3 inhibition by lithium chloride, 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8), or GSK-3 small interfering RNA can decrease viability of SKOV3 and SKOV3-TR30 ovarian cancer cells. Additionally, lithium chloride-treated SKOV3 xenograft mice had a significant reduction in tumor growth compared with control-treated animals.ConclusionOur findings suggest that overexpression and aberrant activation of GSK-3 may contribute to progression and poor prognosis in ovarian cancer. Inhibition of GSK-3 may be a potential therapy for ovarian cancer.

Menadione induces the formation of reactive oxygen species and depletion of GSH-mediated apoptosis and inhibits the FAK-mediated cell invasion

Menadione induces apoptosis in tumor cells. However, the mechanism of apoptosis in ovarian cancer cells exposed to menadione is not clear. In addition, it is unclear whether menadione-induced apoptosis is mediated by the depletion of glutathione (GSH) contents that is associated with the formation of reactive oxygen species. Furthermore, the effect of menadione on the invasion and migration of human epithelial ovarian cancer cells has not been studied. Therefore, we investigated the effects of menadione exposure on apoptosis, cell adhesion, and cell migration using the human epithelial ovarian carcinoma cell lines OVCAR-3 and SK-OV-3. The results suggest that menadione may induce apoptotic cell death in ovarian carcinoma cell lines by activating the mitochondrial pathway and the caspase-8- and Bid-dependent pathways. The apoptotic effect of menadione appears to be mediated by the formation of reactive oxygen species and the depletion of GSH. Menadione inhibited fetal-bovine-serum-induced cell adhesion and migration of OVCAR-3 cells, possibly through the suppression the focal adhesion kinase (FAK)-dependent activation of cytoskeletal-associated components. Therefore, menadione might be beneficial in the treatment of epithelial ovarian adenocarcinoma and combination therapy.

Immunosuppression through constitutively activated NF-κB signalling in human ovarian cancer and its reversal by an NF-κB inhibitor.

Background:Although T-cell immunity is thought to be involved in the prognosis of epithelial ovarian cancer (EOC) patients, immunosuppressive conditions hamper antitumour immune responses. Thus, their mechanisms and overcoming strategies need to be investigated.Methods:The role of NF-κB in human EOC cells and macrophages was evaluated by in vitro production of immunosuppressive IL-6 and IL-8 by EOC cells and in vivo analysis of immune responses in nude mice implanted with human EOC cells using an NF-κB inhibitor DHMEQ.Results:In EOC patients, increased plasma IL-6, IL-8, and arginase were observed. The NF-κB inhibitor DHMEQ inhibited the production of IL-6 and IL-8 by EOC cell lines. Immunosuppression of human DCs and macrophages by culture supernatant of EOC cells was reversed with the pretreatment of DHMEQ. Administration of DHMEQ to nude mice implanted with human EOC resulted in the restoration of T-cell stimulatory activity of murine DCs along with the reduction of tumour accumulation and arginase expression of MDSCs. Nuclear factor-κB inhibition in tumour-bearing mice also enhanced antitumour effects of transferred murine naive T cells.Conclusions:NF-κB is involved in the immunosuppression induced by human EOC, and its inhibitor may restore antitumour immune responses, indicating that NF-κB is an attractive target for EOC treatment.

Promoter hypermethylation influences the suppressive role of maternally expressed 3, a long non-coding RNA, in the development of epithelial ovarian cancer.

Maternally expressed 3 (MEG3) is a long non-coding RNA that can activate p53 and inhibit tumorigenesis and progression of various types of cancers. However, the role of MEG3 in epithelial ovarian cancer (EOC) is still unknown. The aim of the present study was to confirm whether MEG3 is downregulated in human EOC, determine its possible mechanism of action and elucidate the role of MEG3 in EOC. Differences in the expression of MEG3 and in the methylation status of the MEG3 promoter between EOC and normal ovary were analyzed using RT-PCR and methylation-specific PCR (MSP), respectively. MTT and EdU assays and flow cytometric analysis were used to assess the growth of ovarian cancer cells after overexpression of MEG3. The target genes regulated by MEG3 were detected with the Dual Luciferase Reporter system. The expression levels of target genes were confirmed using RT-PCR and western blotting. In contrast to normal ovarian tissues, the expression of MEG3 was absent or decreased in most EOC tissues as well as in human EOC cell lines, and the promoter of the MEG3 gene was highly methylated in both cancer tissues and cell lines. Treatment with 5-aza-2-deoxycytidine reversed the promoter hypermethylation and increased MEG3 expression. In addition, ectopic expression of MEG3 suppressed the proliferation and growth of OVCAR3 cells and promoted apoptosis. Finally, MEG3 activated p53 in OVCAR3 cells. In conclusion, our data suggest that MEG3 is epigenetically silenced in EOC due to promoter hypermethylation, which may contribute to the development of EOC.

Overexpression of CARMA3 is associated with advanced tumor stage, cell cycle progression, and cisplatin resistance in human epithelial ovarian cancer.

CARD recruited membrane associated protein 3 (CARMA3) overexpression has been found in several human cancers. However, its expression pattern and biological roles in human ovarian cancers are not clear. In this study, we examined the expression pattern of CARMA3 in 101 ovarian cancer specimens. We found that 52 (51.5 %) showed CARMA3 overexpression. CARMA3 overexpression positively correlated with tumor histology and advanced FIGO stage. CARMA3 depletion in ovarian cancer cell lines A2780 and HO8910 inhibited ovarian cancer cell proliferation and blocked cell cycle progression. CARMA3 depletion also sensitized ovarian cancer cells to cisplatin-induced cytotoxicity. In addition, Western blot showed that CARMA3 depletion downregulated cyclin D1, cyclin E, and Bcl-2 levels. In conclusion, our data provides evidence that CARMA3 is overexpressed in ovarian cancers and associated with advanced stage. CARMA3 regulates the ovarian cancer cell proliferation, cell cycle progression, and chemoresistance.