Carboplatin In Ovarian Cancer Cells Research Articles

PpIX-enabled fluorescence-based detection and photodynamic priming of platinum-resistant ovarian cancer cells under fluid shear stress.

Over 75% percent of ovarian cancer patients are diagnosed with advanced-stage disease characterized by unresectable intraperitoneal dissemination and the presence of ascites, or excessive fluid build-up within the abdomen. Conventional treatments include cytoreductive surgery followed by multi-line platinum and taxane chemotherapy regimens. Despite an initial response to treatment, over 75% of patients with advanced-stage ovarian cancer will relapse and succumb to platinum-resistant disease. Recent evidence suggests that fluid shear stress (FSS), which results from the movement of fluid such as ascites, induces epithelial-to-mesenchymal transition and confers resistance to carboplatin in ovarian cancer cells. This study demonstrates, for the first time, that FSS-induced platinum resistance correlates with increased cellular protoporphyrin IX (PpIX), the penultimate downstream product of heme biosynthesis, the production of which can be enhanced using the clinically approved pro-drug aminolevulinic acid (ALA). These data suggest that, with further investigation, PpIX could serve as a fluorescence-based biomarker of FSS-induced platinum resistance. Additionally, this study investigates the efficacy of PpIX-enabled photodynamic therapy (PDT) and the secretion of extracellular vesicles under static and FSS conditions in Caov-3 and NIH:OVCAR-3 cells, two representative cell lines for high-grade serous ovarian carcinoma (HGSOC), the most lethal form of the disease. FSS induces resistance to ALA-PpIX-mediated PDT, along with a significant increase in the number of EVs. Finally, the ability of PpIX-mediated photodynamic priming (PDP) to enhance carboplatin efficacy under FSS conditions is quantified. These preliminary findings in monolayer cultures necessitate additional studies to determine the feasibility of PpIX as a fluorescence-based indicator, and mediator of PDP, to target chemoresistance in the context of FSS.

Abstract B100: Perfluoroalkyl substances (PFAS) induce platinum resistance in ovarian cancer through altering mitochondrial function

Abstract Platinum resistance is a major barrier to the effective treatment of advanced-stage ovarian cancer; however, factors leading to the development of resistance are not well understood. In fact, the role of environmental endocrine disrupting chemicals, such as perfluoroalkyl substances (PFAS), have seldom been explored. This is important because select PFAS have been linked to adverse reproductive outcomes in females including endometriosis, oocyte apoptosis, infertility, and increased even ovarian cancer risk at very high exposure levels. The relationship between PFAS and adverse female reproductive outcomes, as well as reports of other endocrine disruptors leading to therapy resistance, led, in the current study, to the evaluation of the effect of PFAS exposure on response to carboplatin in ovarian cancer cells. We recently showed that select PFAS, at human-relevant concentrations, induced carboplatin resistance in OVCAR-3 and Caov-3 cells; however, the mechanism underlying the onset of resistance remains largely unknown. Since platinum-resistant ovarian cancer is characterized, in part, by increased mitochondrial networks and enhanced bioenergetic capacities, the central hypothesis of this study is that PFAS induce alterations to mitochondrial biology. Mitochondrial endpoints of interest included redox ratio and superoxide production. To measure redox ratio, nicotinamide dinucleotide (NADH) and flavin adenine dinucleotide (FAD), which are inherently fluorescent, were measured using a fluorescence plate reader. Since NADH and FAD are metabolites produced via oxidative phosphorylation and glycolysis, evaluating redox ratio can provide an understanding of which pathway is preferred in the presence of environmental stimuli like PFAS. In OVCAR-3 and Caov-3 cells, baseline NADH:FAD ratios were 3.3 and 3.5, respectively. After 48 hours of PFAS exposure, NADH:FAD ratios of OVCAR-3 and Caov-3 cells ranged from 8-10 or 6-10, respectively. This increase after PFAS exposure could suggest enhanced energy production capabilities that warrant further investigation. As an additional measure, superoxide production was measured using flow cytometry. OVCAR-3 and Caov-3 cells were exposed to PFAS for 6 days prior to isolating cell pellets and incubating them with MitoSOX (mitochondrial) and SYTOX Blue (nuclear) dyes. After 15–30-minute incubations, samples were run on the flow cytometer. Compared to controls, superoxide production in PFAS-exposed ovarian cancer cells increased by up to 200%. Often, cancer cells have elevated levels of reactive oxygen species due to enhanced energy production and signaling pathways, thus this finding further suggests that PFAS affect mitochondrial energy pathways. Altogether, these data show that PFAS exposure, which can induce carboplatin resistance in OVCAR-3 and Caov-3 cells, increases redox ratios and superoxide production in ovarian cancer cells. Therefore, targeting alterations in mitochondrial biology arising from PFAS exposure using precision medicine could be effective in overcoming platinum resistance in ovarian cancer. Citation Format: Brittany P. Rickard, Marta Overchuk, Vesna A. Chappell, Carl D. Bortner, Victoria L. Bae-Jump, Suzanne E. Fenton, Imran Rizvi. Perfluoroalkyl substances (PFAS) induce platinum resistance in ovarian cancer through altering mitochondrial function [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr B100.

Antagonism of Bcl-XL is necessary for synergy between carboplatin and BH3 mimetics in ovarian cancer cells.

BackgroundBH3 mimetics are a class of drugs that antagonize the Bcl-2 family of apoptosis inhibitors. We have previously shown that these compounds can potentiate the activity of carboplatin against several ovarian cancer cell lines. However, recent clinical studies have highlighted that BH3 mimetics which antagonise Bcl-XL are associated with significant thrombocytopenia. This has led to the development of ABT-199 which specifically inhibits Bcl-2. Unfortunately, Bcl-XL appears to be more frequently deregulated in ovarian cancer than Bcl-2. We therefore compared the ability of ABT-199, and the Bcl-XL selective compound WEHI-539, to potentiate the activity of carboplatin in ovarian cancer cell lines.MethodsWEHI-539, ABT-737 and ABT-199 were tested in combination with carboplatin using a panel of 6 ovarian cancer cell lines. The activity of the drugs was evaluated using cell growth assays, staining with trypan bue and measurement of apoptosis by measuring caspase 3/7 activity, PARP cleavage and annexin-V/propidium iodide staining.ResultsWe found that WEHI-539 and ABT-737, but not ABT-199, were synergistic with carboplatin in cell growth assays and potentiated cell death when assessed by trypan blue staining. Furthermore, WEHI-539 and ABT-737 augmented carboplatin induced caspase 3/7 activity, PARP cleavage and annexin V labelling, but ABT-199 failed to do so.ConclusionsThese observations suggest that compounds which target Bcl-XL are necessary if BH3 mimetics are to be successfully used to treat patients with ovarian cancer and this highlights the need to develop strategies to minimize thrombocytopenia induced by such compounds.

Promotive role of recombinant HE4 protein in proliferation and carboplatin resistance in ovarian cancer cells.

Available evidence on the proliferation-promoting effect of HE4 remains controversial, and few studies have been carried out on the molecular mechanism of chemoresistance mediated by HE4. The aim of the present study was to investigate the influence of exogenous recombinant HE4 protein on proliferation and resistance to carboplatin in ovarian cancer cells. The human ovarian cancer cell line (SKOV-3) was exposed to recombinant HE4 protein (0-1 µg/ml) for different durations based on the schemes. Cell viability was evaluated by Cell Counting Kit-8 and colony formation assays. Cell cycle distribution and apoptosis were analyzed by flow cytometry. Markers of apoptosis (Bax and Bcl-2) were assessed by western blotting. Furthermore, Affymetrix microarray analysis was performed to investigate transcriptome profiling. The differential expression of four genes was verified by quantitative real-time PCR. The HE4 protein enhanced cell viability, promoted accumulation of cells in the G2/M phase and attenuated carboplatin-induced apoptosis. HE4 markedly decreased the Bax/Bcl-2 ratio. Candidate genes (387) (236 upregulated and 151 downregulated) were obtained by microarray analysis. Among those upregulated, several Gene Ontology (GO) terms related to cell cycle regulation and proliferation were significantly overrepresented and those within the downregulated dataset included genes involved in several aspects of the DNA damage response such as positive regulation of apoptosis. No information concerning the EGFR-MAPK pathways in a recent report on HE4 was acquired. The mRNA expression of the candidate genes determined by quantitative real-time PCR was significantly correlated with the microarray data. The present study indicates that the HE4 protein plays a promotive role in the proliferation and resistance to carboplatin in ovarian cancer cells, implicating the value of HE4 to predict tumor growth potential and resistance to platinum-based chemotherapy in epithelial ovarian cancer (EOC).

Microenvironment mesenchymal cells protect ovarian cancer cell lines from apoptosis by inhibiting XIAP inactivation

Epithelial ovarian carcinoma is characterized by high frequency of recurrence (70% of patients) and carboplatin resistance acquisition. Carcinoma-associated mesenchymal stem cells (CA-MSC) have been shown to induce ovarian cancer chemoresistance through trogocytosis. Here we examined CA-MSC properties to protect ovarian cancer cells from carboplatin-induced apoptosis. Apoptosis was determined by Propidium Iodide and Annexin-V-FITC labelling and poly-ADP-ribose polymerase cleavage analysis. We showed a significant increase of inhibitory concentration 50 and a 30% decrease of carboplatin-induced apoptosis in ovarian cancer cells incubated in the presence of CA-MSC-conditioned medium (CM). A molecular analysis of apoptosis signalling pathway in response to carboplatin revealed that the presence of CA-MSC CM induced a 30% decrease of effector caspases-3 and -7 activation and proteolysis activity. CA-MSC secretions promoted Akt and X-linked inhibitor of apoptosis protein (XIAP; caspase inhibitor from inhibitor of apoptosis protein (IAP) family) phosphorylation. XIAP depletion by siRNA strategy permitted to restore apoptosis in ovarian cancer cells stimulated by CA-MSC CM. The factors secreted by CA-MSC are able to confer chemoresistance to carboplatin in ovarian cancer cells through the inhibition of effector caspases activation and apoptosis blockade. Activation of the phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathway and the phosphorylation of its downstream target XIAP underlined the implication of this signalling pathway in ovarian cancer chemoresistance. This study reveals the potentialities of targeting XIAP in ovarian cancer therapy.

Aurora kinase inhibitor VE 465 synergistically enhances cytotoxicity of carboplatin in ovarian cancer cells through induction of apoptosis and downregulation of histone 3

Aurora kinases are essential for regulation of chromosome segregation and cytokinesis during mitosis and play a role in growth and progression of human tumors, including ovarian cancer. Aurora A and Aurora B are frequently overexpressed in high-grade and low-grade ovarian cancers. Targeting Aurora kinases has great potential for improving the efficacy of chemotherapies of ovarian cancer. In this study, we investigated whether the Aurora kinase inhibitor, VE 465, can enhance the anti-tumor activity of carboplatin in human ovarian cancer cells. The antitumor activity of VE 465 was tested by MTT proliferative assay in multiple established human epithelial ovarian cancer cell lines of varying p53 status. VE 465 and carboplatin had a synergistic effect on cell viability in both platinum-sensitive and -resistant ovarian cancers. The growth-inhibitory effect was accompanied by reduction in expression of histone 3 and an increase in apoptosis. We conclude that VE 465 enhances the efficacy of carboplatin agents in ovarian carcinoma.

A novel hedgehog pathway smoothened inhibitor (BMS-833923) demonstrates in vitro synergy with carboplatin in ovarian cancer cells

A novel hedgehog pathway smoothened inhibitor (BMS-833923) demonstrates in vitro synergy with carboplatin in ovarian cancer cells

Dasatinib (BMS-35482) has synergistic activity with paclitaxel and carboplatin in ovarian cancer cells

PurposeTo explore the activity of dasatinib alone and in combination with paclitaxel and carboplatin in ovarian cancer cells and to determine if dasatinib activity can be predicted based on evaluation of the SRC pathway. Experimental designMicroarray analysis was performed for IGROV1, OVCAR3, A2780 and SKOV3 ovarian cancer cells and the status of the genomic SRC signature pathway was determined. Cells were treated with carboplatin, paclitaxel and dasatinib individually and in combination. Pre- and post-treatment phospho-SRC (pSRC) and SRC protein expression was determined. Dose–response curves were constructed, and drug interaction was assessed by the Combination Index (CI) method. ResultsSRC protein expression levels reflected the SRC pathway genomic signature in the cell lines with the lowest (SKOV3) and highest (IGROV1) pathway expression, but not in those with intermediate expression (OVCAR3, A2780). Dasatinib treatment caused loss of pSRC in all cell lines, with 50% growth inhibition for IGROV1 at 70nM, OVCAR3 at 34nM, A2780 at 4.1μM and SKOV3 at 530nM. Dasatinib combined with cytotoxics yielded a synergistic effect (CI=0.46 to 0.79) in all cell lines except SKOV3. ConclusionDasatinib in combination with standard chemotherapeutic agents appears to interact in a synergistic manner in some ovarian cancer cell lines. Further research is needed to evaluate tumor cell characteristics which predict response to dasatinib.

Abstract 670: Aurora kinase inhibitor VE 465 synergistically enhances cytotoxicity of carboplatin in ovarian cancer cells through induction of apoptosis and downregulation of histone 3

Abstract Aurora kinases are essential for the regulation of chromosome segregation and cytokinesis during mitosis and play a role in tumorigenesis and progression in human tumors, including ovarian cancer. Aurora A and Aurora B are frequently overexpressed in high-grade and low-grade ovarian cancers. Targeting aurora kinases has great potential for improving the efficacy of treatment of ovarian cancer. In this study, we investigated whether the Aurora kinase inhibitor VE 465 will enhance the antitumor activity of carboplatin in human ovarian cancer cells. Cell viability was tested using the MTT assay in seven established human epithelial ovarian cancer cell lines with varying p53 status. We found that VE 465 and carboplatin had a synergistic effect (defined by the combination index) in both platinum-sensitive and -resistant ovarian cancers and that the growth-inhibitory effect was accompanied by reduction in expression of histone 3 and an increase in apoptosis. Aurora kinase inhibition in combination with carboplatin chemotherapy is an attractive combination for further development. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 670.

Autotaxin delays apoptosis induced by carboplatin in ovarian cancer cells

Drug resistance remains a barrier to the effective long term treatment of ovarian cancer. We have established an RNAi-based screen to identify genes which confer resistance to carboplatin or paclitaxel. To validate the screen we showed that siRNA interfering with the apoptosis regulators FLIP and Bcl-X L conferred sensitivity to paclitaxel and carboplatin respectively. The expression of 90 genes which have previously been shown to be over-expressed in drug-resistant ovarian cancer was inhibited using siRNA and the impact on sensitivity to carboplatin and paclitaxel was assessed. ENPP2 was identified as a candidate gene causing drug resistance. ENPP2 encodes autotaxin, a phospholipase involved in the synthesis of the survival factor lysophosphatidic acid. siRNA directed to ENPP2 resulted in earlier apoptosis following treatment with carboplatin. 2-carbacyclic phosphatidic acid (ccPA 16:1), a small molecule inhibitor of autotaxin, also accelerated apoptosis induced by carboplatin. Stable ectopic expression of autotaxin in OVCAR-3 cells led to a delay in apoptosis. When serum was withdrawn to remove exogenous LPA, ccPA caused a pronounced potentiation of apoptosis induced by carboplatin in cells expressing autotaxin. These results indicate that autotaxin delays apoptosis induced by carboplatin in ovarian cancer cells.

Combining Epigenetic and Cytotoxic Therapy in the Treatment of Solid Tumors

Combining Epigenetic and Cytotoxic Therapy in the Treatment of Solid Tumors