Exposure Of Ovarian Cancer Cells Research Articles

Proteomic insight towards key modulating proteins regulated by the aryl hydrocarbon receptor involved in ovarian carcinogenesis and chemoresistance

Gynecological malignancies pose a severe threat to female lives. Ovarian cancer (OC), the most lethal gynecological malignancy, is clinically presented with chemoresistance and a higher relapse rate. Several studies have highly correlated the incidence of OC to exposure to environmental pollutants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a process mainly mediated through activating the aryl hydrocarbon receptor (AhR). We have previously reported that exposure of OC cells to TCDD, an AhR activator, significantly modulated the expression of several genes that play roles in stemness and chemoresistance. However, the effect of AhR activation on the whole OC cell proteome aiming at identifying novel druggable targets for both prevention and treatment intervention purposes remains unrevealed. For this purpose, we conducted a comparative proteomic analysis of OC cells A2780 untreated/treated with TCDD for 24 h using a mass spectrometry-based label-free shotgun proteomics approach. The most significantly dysregulated proteins were validated by Western blot analysis. Our results showed that upon AhR activation by TCDD, out of 2598 proteins identified, 795 proteins were upregulated, and 611 were downregulated. STRING interaction analysis and KEGG-Reactome pathway analysis approaches identified several significantly dysregulated proteins that were categorized to be involved in chemoresistance, cancer progression, invasion and metastasis, apoptosis, survival, and prognosis in OC. Importantly, selected dysregulated genes identified by the proteomic study were validated at the protein expression levels by Western blot analysis. In conclusion, this study provides a better understanding of the the cross-talk between AhR and several other molecular signaling pathways and the role and involvement of AhR in ovarian carcinogenesis and chemoresistance. Moreover, the study suggests that AhR is a potential therapeutic target for OC prevention and maintenance. SignificanceTo our knowledge, this is the first study that investigates the role and involvement of AhR and its regulated genes in OC by performing a comparative proteomic analysis to identify the critical proteins with a modulated expression upon AhR activation. We found AhR activation to play a tumor-promoting and chemoresistance-inducing role in the pathogenesis of OC. The results of our study help to devise novel therapeutics for better management and prevention and open the doors to finding novel biomarkers for the early detection and prognosis of OC.

S1PR1 regulates ovarian cancer cell senescence through the PDK1-LATS1/2-YAP pathway

Cell senescence deters the activation of various oncogenes. Induction of senescence is, therefore, a potentially effective strategy to interfere with vital processes in tumor cells. Sphingosine-1-phosphate receptor 1 (S1PR1) has been implicated in various cancer types, including ovarian cancer. The mechanism by which S1PR1 regulates ovarian cancer cell senescence is currently elusive. In this study, we demonstrate that S1PR1 was highly expressed in human ovarian cancer tissues and cell lines. S1PR1 deletion inhibited the proliferation and migration of ovarian cancer cells. S1PR1 deletion promoted ovarian cancer cell senescence and sensitized ovarian cancer cells to cisplatin chemotherapy. Exposure of ovarian cancer cells to sphingosine-1-phosphate (S1P) increased the expression of 3-phosphatidylinositol-dependent protein kinase 1 (PDK1), decreased the expression of large tumor suppressor 1/2 (LATS1/2), and induced phosphorylation of Yes-associated protein (p-YAP). Opposite results were obtained in S1PR1 knockout cells following pharmacological inhibition. After silencing LATS1/2 in S1PR1-deficient ovarian cancer cells, senescence was suppressed and S1PR1 expression was increased concomitantly with YAP expression. Transcriptional regulation of S1PR1 by YAP was confirmed by chromatin immunoprecipitation. Accordingly, the S1PR1-PDK1-LATS1/2-YAP pathway regulates ovarian cancer cell senescence and does so through a YAP-mediated feedback loop. S1PR1 constitutes a druggable target for the induction of senescence in ovarian cancer cells. Pharmacological intervention in the S1PR1-PDK1-LATS1/2-YAP signaling axis may augment the efficacy of standard chemotherapy.

Exposure to escalating olaparib does not induce acquired resistance to PARPi and to other chemotherapeutic compounds in ovarian cancer cell lines

Poly (ADP-ribose) polymerase (PARP)-inhibitors (PARPi) such as olaparib and niraparib are currently used as a treatment option for BRCA-deficient tumors and also show efficacy in platinum-sensitive tumors. However, resistance to PARPi occurs in numerous patients and in particular acquired PARPi resistance presents a major obstacle in the treatment of these tumors. In the present study, it was investigated whether stepwise exposure of ovarian cancer cells to escalating concentrations of olaparib produced subcells with acquired resistance to PARPi and/or acquired cross-resistance to platinum compounds, paclitaxel, and doxorubicin. To this aim, the sensitivity of fourteen ovarian cancer cell lines, including nine with TP53-mutations and five carrying BRCA-mutations, to olaparib and niraparib was determined and a subset of seven cell lines was selected to investigate the potential of olaparib to produce resistance. It was identified that escalating olaparib did neither produce subcells with acquired PARPi-resistance nor did it produce acquired cross-resistance to platinum compounds, doxorubicin, and paclitaxel. This finding was independent of the cells' TP53 and BRCA mutation status. CRISPR-Cas9 mediated deletion of PARP1 did not affect sensitivity to PARPi, platinum compounds, doxorubicin, and paclitaxel. In addition, olaparib sensitivity correlated with niraparib sensitivity, but BRCA-mutated cells were not more sensitive to PARPi. Moreover, PARPi sensitivity associated with cross-sensitivity not only to platinum compounds but also to anthracylines, paclitaxel, and inhibitors of histone deacetylases. These in vitro data indicated that olaparib exposure is unlikely to produce an acquired resistance phenotype and that PARPi-sensitive ovarian cancer cells are also cross-sensitive to non-platinum and even to compounds not directly interacting with the DNA.

Proapoptotic Protein Smac Mediates Apoptosis in Ovarian Cancer Cells When ‎Treated with the Carpachromene ‎

IntroductionWe also investigated the Carpachromene in the cytotoxicity studies against common human ovarian cancer cell ‎line i.e., SW 626, in-vitro.Material and methodsCell viability of Carpachromene was very low against common ‎human ovarian cancer ‎cell line i.e. SW 626 without any cytotoxicity on normal cell line. To compare the ‎biological activities of molecules, the enzymes used are α-glucosidase, acetylcholinesterase, respectively. Finally, ‎calculations were made using the molecular docking method to compare the biological activity of the ‎carpachromene molecule. We then examined whether the release of Smac is necessary for apoptosis in ovarian ‎cancer cells using the SW 626‎ cell line. We first examined mitochondrial and cytosolic Smac levels after ‎Carpachromene treatment. ‎ResultsFollowing the docking calculations, the properties of the carpachromene molecule ‎were examined by ADME/T analysis in order to be used as a drug in the future. In addition, the anti-oxidant ‎properties of the molecules were examined in both gas and water phase with the HF/6-31g basis set with the ‎Gaussian software program. As shown, exposure of ovarian cancer cells to Carpachromene decreased ‎mitochondrial Smac and increased cytosolic Smac levels in a time-dependent fashion. As depicted in results, a ‎decrease in Smac expression was confirmed by Western blot. Silencing of Smac significantly inhibited ‎Carpachromene-induced caspase-3 cleavage and attenuated apoptosis in these cells Moreover, overexpression of ‎a Smac heptapeptide (Smac-N7) enhanced Carpachromene-induced cell deathConclusionsAccording to the above findings, the Carpachromene may be administrated for the treatment of several types of ‎human ovarian cancer in humans. ‎

HIF-1α Regulated WTAP Overexpression Promote Warburg Effect of Ovarian Cancer by m6A-Dependent Manner

N6-methyladenosine (m6A), the methylation of the N6 nitrogen on adenosine, acts as the most common internal modification of eukaryotic mRNA. The dynamic and reversible m6A RNA modification established and erased by N6-methyltransferases and demethylases regulates gene expression and determines cell fate. In this study, we find for the first time that exposure of ovarian cancer cells to hypoxia significantly increases the expression of WT1 associated protein(WTAP), a critical m6A methylase which proved to be induced by a hypoxia factor (HIF)-1α dependent manner, and expression of WTAP in ovarian cancer cells is significantly correlated with the clinicopathological characteristics and up-regulation of WTAP predicts poor prognosis of ovarian cancer patients. Knockdown/ Overexpress of WTAP in human ovarian cancer cells substantially reduces/enhances their proliferative and invasive capacity both in vitro and in vivo. Moreover, We discover that WTAP interacts with DGCR8, a vital microprocessor protein, regulating the primary microRNA 200 process in an m6A-dependent manner. Further experiments demonstrate that microRNA200 could positively regulate HK2 and promote Warburg effect. These studies reveal that HIF-1α upregulated WTAP expression mediates primary miRNA processing, accelerates the Warburg effect and promotes the occurrence and development of tumor, thus providing a novel perspective on m6A modification in ovarian cancer progression. Funding Information: This study was supported by grants from the Natural Science Foundation of Anhui Province (2008085QH422). Declaration of Interests: The authors have declared that no competing interest exists. Ethics Approval Statement: All human ovary tissues were obtained with informed consent, and the ethical review committee approved all protocols of the World Health Organization Collaborating Center for Research in Human Production. Animal studies were approved by the Institutional Animal Care and Use Committee of Second Military Medical University, Shanghai, China.

EGFR-Specific Tyrosine Kinase Inhibitor Modifies NK Cell-Mediated Antitumoral Activity against Ovarian Cancer Cells.

The adverse prognosis of most patients with ovarian cancer is related to recurrent disease caused by resistance to chemotherapeutic and targeted therapeutics. Besides their direct activity against tumor cells, monoclonal antibodies and tyrosine kinase inhibitors (TKIs) also influence the antitumoral activity of immune cells, which has important implications for the design of immunotherapies. In this preclinical study, we treated different ovarian cancer cell lines with anti-epidermal growth factor receptor (EGFR) TKIs and co-incubated them with natural killer (NK) cells. We studied treatment-related structural and functional changes on tumor and immune cells in the presence of the anti-EGFR antibody cetuximab and investigated NK-mediated antitumoral activity. We show that long-term exposure of ovarian cancer cells to TKIs leads to reduced responsiveness of intrinsically sensitive cancer cells over time. Inversely, neither long-term treatment with TKIs nor cetuximab could overcome the intrinsic resistance of certain ovarian cancer cells to anti-EGFR agents. Remarkably, tumor cells pretreated with anti-EGFR TKIs showed increased sensitivity towards NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC). In contrast, the cytokine secretion of NK cells was reduced by TKI sensitization. Our data suggest that sensitization of tumor cells by anti-EGFR TKIs differentially modulates interactions with NK cells. These data have important implications for the design of chemo-immuno combination therapies in this tumor entity.

Contribution of reactive oxygen species to ovarian cancer cell growth arrest and killing by the anti-malarial drug artesunate.

Ovarian cancer is a leading cause of cancer-related death in women and the most lethal gynecological malignancy in the developed world. The morbidity and mortality of ovarian cancer underscore the need for novel treatment options. Artesunate (ART) is a well-tolerated anti-malarial drug that also has anti-cancer activity. In this study, we show that ART inhibited the in vitro growth of a panel of ovarian cancer cell lines, as well as the growth of ovarian cancer cells isolated from patients. Moreover, ART decreased tumor growth in vivo in a mouse model of ovarian cancer. ART-treated ovarian cancer cells showed a strong induction of reactive oxygen species (ROS) and reduced proliferation. ROS-dependent cell cycle arrest occurred in the G2/M phase whereas ROS-independent cell cycle arrest occurred in the G1 phase, depending on the concentration of ART to which ovarian cancer cells were exposed. The anti-proliferative effect of ART was associated with altered expression of several key cell cycle regulatory proteins, including cyclin D3, E2F-1, and p21, as well as inhibition of mechanistic target of rapamycin signaling. Exposure of ovarian cancer cells to higher concentrations of ART resulted in ROS-dependent DNA damage and cell death. Pretreatment of ovarian cancer cells with a pan-caspase inhibitor or ferroptosis inhibitor decreased but did not completely eliminate ART-mediated cytotoxicity, suggesting the involvement of both caspase-dependent and caspase-independent pathways of killing. These data show that ART has potent anti-proliferative and cytotoxic effects on ovarian cancer cells, and may therefore be useful in the treatment of ovarian cancer. © 2016 Wiley Periodicals, Inc.

Exposure of Ovarian Cancer Cells Expressing Estrogen Receptors to Endocrine Disrupting Chemicals Resulted in the Gene Alteration with Proliferation and Differentiation.

Exposure of Ovarian Cancer Cells Expressing Estrogen Receptors to Endocrine Disrupting Chemicals Resulted in the Gene Alteration with Proliferation and Differentiation.

Effect of plasmid-mediated stable interferon-γ expression on proliferation and cell death in the SKOV-3 human ovarian cancer cell line

Introduction: High interferon-γ (IFN-γ) expression in tumors has been reported to be a favorable prognostic marker. Continuous exposure of ovarian cancer cells to IFN-γ was previously shown to result in significant growth inhibition and apoptosis. Our goal in this study was to evaluate the effect of plasmid-mediated stable IFN-γ expression on the SKOV-3 human ovarian carcinoma cell line.Methods: SKOV-3 cells were stably transfected with the pEGFP-IFN-γ plasmid. IFN-γ mRNA was detected by RT-PCR and IFN-γ protein expression was measured by ELISA. Proliferation and cell death in transfected SKOV-3 cells were measured by methyl-thiazolyl tetrazolium (MTT) assay and Hoechst 33258 staining, respectively and compared with untransfected and empty vector-transfected cells.Results: pEGFP-IFN-γ SKOV-3 cells efficiently expressed and secreted IFN-γ. They exhibited significantly decreased cellular proliferation when compared with control untransfected or empty vector-transfected cells (P < 0.05). The mode of cell death was primarily apoptosis.Conclusions: Stable expression of IFN-γ significantly inhibits the proliferation of ovarian carcinoma cells and has the potential to be used in clinical applications to treat ovarian carcinoma in the future.

Concomitant exposure of ovarian cancer cells to docetaxel, CPT-11 or SN-38 and adenovirus-mediated p53 gene therapy

Owing to its central role in multiple cellular functions, p53 is an attractive candidate for gene replacement therapy. We studied the role of adenovirus-mediated p53 gene (p53Ad) therapy on sensitivity of two ovarian cancer cell lines, OVCAR-3 (p53(mut)) and SK-OV-3 (p53(wt)), to docetaxel, CPT-11 and SN-38 exposures. Expressions of Bcl-XL, Bcl-XS, p53, Gadd45, c-fos, p21(waf1/cip1), Bax, Bcl-2 and Mcl-1 were measured after concomitant p53Ad and drug exposures. In SK-OV-3 cells containing a normal p53 gene, p53Ad alone or concomitantly with docetaxel, CPT-11 or SN-38 exposures did not have an effect on cell growth, cell cycle distribution or induction of apoptosis. In OVCAR-3 cells, p53 gene therapy inhibited the cell growth and sensitized cells to CPT-11/SN-38, but not to docetaxel. Growth inhibition and sensitization were results of G2M cell cycle arrest and increased apoptosis. In SK-OV-3 cells, but not in OVCAR-3 cells, CPT-11/SN-38 exposures alone increased p21(waf1/cip1) expression. The p53Ad therapy induced strong p21(waf1/cip1) expression in both cell lines. In addition, the expression of Bax and expression ratios Bax/Bcl-2 and Bax/Bcl-XL increased in p53Ad-infected OVCAR-3 cells, but not in SK-OV-3 cells. These expression ratios were further increased in p53Ad+CPT-11/SN-38-exposed OVCAR-3 samples. These results support the combination of p53 gene therapy with topoisomerase I inhibitors SN-38/CPT-11 when tumour cells contain mutated p53. When p53 status is normal, p53 gene therapy is not effective alone or concomitantly with CPT-11/SN-38. Increased expression ratios of Bax/Bcl-2 and Bax/Bcl-XL might serve as positive markers for effective p53 gene therapy and concomitant topoisomerase I inhibitor therapy.

Evaluation of the antiangiogenic effect of Taxol in a human epithelial ovarian carcinoma cell line.

Angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) are major ligands for the endothelium-specific tyrosine kinase receptor Tie-2 and are important regulators of endothelial cell survival. In the presence of vascular endothelial growth factor (VEGF), vessel destabilization by Ang-2 has been hypothesized to induce an angiogenic response, but in the absence of VEGF, Ang-2 leads to vessel regression. In the present study, a human ovarian cancer cell line was used to investigate the possibility that Taxol might affect the expression of Ang-1, Ang-2, and VEGF. KF 28, a single-cell clone of a human ovarian epithelial carcinoma cell line, was used. The expression of Ang-1, Ang-2, and VEGF was assessed by quantitative real-time RT-PCR and Western blot analysis or enzyme-linked immunosorbent assay. Conditioned medium was used in the in vitro angiogenesis assay. The concentration of Taxol that inhibited the growth of cells to the level of 50% of control cell growth was 4.65+/-0.35 nM. Quantitative real-time RT-PCR indicated that Ang-1 gene expression was significantly decreased by exposure to 2 nM Taxol for 168 h ( P<0.05 vs control cells). Western blot analysis confirmed that the Ang-1 protein level was decreased by exposure to 2 nM Taxol for 168 h. Ang-2 gene expression did not significantly differ between control cells and those exposed to Taxol for any of the indicated times. The Ang-1/ Ang-2 gene expression ratio was significantly decreased by exposure to Taxol for 168 h ( P<0.05 vs control cells). VEGF gene expression was significantly decreased by exposure to Taxol for 168 h ( P<0.05). The VEGF concentration in the conditioned medium was also significantly reduced by exposure to Taxol for 168 h ( P<0.05). Conditioned medium collected following Taxol treatment for 168 h significantly inhibited endothelial tubule formation ( P<0.05). Cell growth did not significantly differ between control cells and those exposed to Taxol for any of the indicated times. Our results show that exposure of ovarian cancer cells to a low concentration of Taxol may inhibit the initiating event in angiogenesis, namely, vascular regression. This information might be valuable in the development of new therapeutic interventions for epithelial ovarian cancer.