Project description:Chemo-resistance to platinum such as cisplatin is critical in the treatment of ovarian cancer. Recent evidences have linked epithelial-mesenchymal transition (EMT) with the drug resistance as a contributing mechanism. The current study explored the connection between cellular responses to cisplatin with EMT in ovarian cancer. 46 ovarian carcinoma cell lines expression data with and without Cisplatin treatment.
Project description:Cisplatin and carboplatin are the primary first-line therapies for the treatment of ovarian cancer. However, resistance to these platinum-based drugs occurs in the large majority of initially responsive tumors, subsequently resulting in a poor long-term prognosis. To model the onset of drug resistance, we measured gene expression alterations associated with cisplatin resistance. We treated clonally derived, drug-sensitive A2780 epithelial ovarian cancer cells with increasing concentrations of cisplatin. After 5 cycles of drug selection, the isogenic drug-sensitive (parental A2780) and -resistant (Round5 A2780) cell lines were subjected to mRNA expression microarray analyses.
Project description:The development of drug resistance is still a major impediment for the successful treatment of cancer, such as advanced stage ovarian cancer, which has a 5-year survival rate of only 30%. The molecular processes that contribute to resistance have been extensively studied, however, not much is known about the role of microRNAs. We compared microRNA expression profiles of three isogenic cisplatin sensitive and resistant cell line pairs. The only microRNA that was consistently downregulated (FDR = 0.000) in all resistant cell lines was miR-634. We investigated the effects of miR-634 modulation in ovarian cancer cell lines and patient derived tumor cells. Overexpression of miR-634 gave rise to a modest G1 phase block and enhanced apoptosis. Furthermore, miR-634 resensitized resistant ovarian cancer cell lines and patient derived tumor cells to cisplatin chemotherapy. Similarly, miR-634 enhanced the response of tumor cells to carboplatin and doxorubicin, but not to paclitaxel. We showed that miR-634 regulates cyclin D1 (CCND1), which is required for the G1-S phase transition, explaining the effects on the cell cycle. In addition, miR-634 repressed expression of GRB2, ERK2, RSK1 and RSK2, components of the Ras-MAPK pathway. Altogether, our findings suggest that miR-634 modulates several cancer relevant targets and therefore miR-634 is an attractive therapeutic candidate to resensitize chemotherapy resistant ovarian tumors. The miRNA expression profile was determined of three cisplatin sensitive/resistant cell line pairs (ovarian cancer cell line pair A2780/A2780 DDP; colon cancer cell line pair HCT8/HCT8 DDP; bladder cancer cell line pairT24/T24 DDP10).
Project description:To investigate the main mechanism underlying cisplatin resistance in ovarian cancer, A2780/CDDP and SKOV3/CDDP cell lines were treated with both maggot extracts and cisplatin. We then performed gene expression profiling analysis using data obtained from RNA-seq of A2780 and A2780/CDDP cells.
Project description:Platinum compounds display clinical activity against a wide variety of solid tumors. However, resistance to these agents is a major limitation in cancer therapy. Reduced platinum uptake and increased platinum export are examples of resistance mechanisms that limit the extent of DNA damage. Here, we report the discovery and characterization of the role of ATP11B, a P-type ATPase membrane protein, in cisplatin resistance. ATP11B gene silencing restored the sensitivity of ovarian cancer cell lines to cisplatin in vitro. Combined therapy of cisplatin and ATP11B-siRNA significantly decreased cancer growth in mice bearing ovarian tumors derived from cisplatin-sensitive and -resistant cells. In vitro mechanistic studies on cellular platinum content and cisplatin efflux-kinetics indicated that ATP11B enhances the export of cisplatin from cells. The co-localization of ATP11B with fluorescent cisplatin and with vesicular trafficking proteins such as syntaxin-6 (STX6) and vesicular associated membrane protein 4 (VAMP4) strongly suggests that ATP11B contributes to secretory vesicular transport of cisplatin from Golgi to plasma membrane. In conclusion, silencing ATP11B expression might be a therapeutic strategy to overcome cisplatin resistance. We performed the transfection of control-siRNA and ATP11B-siRNA to both cisplatin-sensitive A2780-PAR and cisplatin-resistant A2780-CP20 cells respectively.
Project description:Understanding the mechanism of resistance in platinum-based regimens for the treatment of high-grade serous ovarian cancer (HGSOC) is important for identifying new therapeutic targets to improve the clinical outcome of ovarian cancer patients. Mass spectrometry-based proteomic strategy was applied to spheroidal cisplatin sensitive and resistant HGSOC generated cell lines in the absence and presence of cisplatin drug. A complete expressed HGSOC proteome and phosphoproteome was characterized in cisplatin sensitive and resistant HGSOC cell lines providing insight into the mechanism of resistance development. PCA analysis showed that phosphorylation of a few proteins provides better classification than the whole proteome of the cellular subtypes. Specifically, a distinctive phosphoproteomic signature between cisplatin sensitive and resistant cell lines in the absence of drug was observed. This same phosphoproteomic signature was observed in our cisplatin sensitive cell line in the absence and presence of drug, indicating a vital role for phosphorylation of proteins in resistance development to cisplatin. The most phosphorylated protein was sequestosome (p62/SQSTM1). Differential expressions of apoptosis by the prognostic factor ratio of Bcl-2/Bax and autophagy, known to be regulated by p62/SQSTM1, was validated in the proteome data and by western blot analysis. A significant increase in apoptosis in the presence of cisplatin was observed in only the sensitive cell line while autophagy revealed increased expression in the resistant relative to sensitive cell line. Furthermore, site specific phosphorylation on 20 modified residues of sequestosome was characterized. Elevated expression of phosphorylation of sequestosome in resistant HGSOC cell lines was validated with western blot analysis. Here, we propose phosphorylation of sequestosome to be a marker and key in cisplatin resistance development in HGOSC ovarian cancers by shuttling ubiquitinated proteins to the autophagy pathway and influencing down-regulation of apoptosis.
Project description:Background. Genome-wide expression changes are associated with development of chemoresistance in patients with ovarian cancer (OVCA); the BCL2 antagonist of cell death (BAD) apoptosis pathway may play a role in clinical outcome. Methods. We analyzed specimens and/or genomic data from 1,406 patients and 116 cancer cell lines. Genome-wide expression changes and cisplatin-resistance were evaluated in OVCA cell lines subjected to a total of 144 (cisplatin)-treatment/recovery cycles. Pathway analysis was performed on genes associated with increasing cisplatin-resistance. BAD protein phosphorylation was studied in patient samples and cell lines, and small interfering RNAs (siRNA) used to explore the pathway as a therapeutic target. We evaluated the influence of BAD-pathway expression on chemosensitivity and/or clinical outcome using genomic data from 60 human cancer cell lines and ovarian, breast, colon, and brain cancers from 1,258 patients. Results. The BAD pathway was associated with evolution of OVCA cell line cisplatin-resistance (P<0.001) and resistance of 7 human cancer cell types to 8 cytotoxic agents (P<0.05). OVCA chemoresistance was associated with BAD protein phosphorylation, and targeted siRNA modulation produced corresponding changes in chemosensitivity. Expression of a 47-gene BAD-pathway signature was associated with survival of 1,258 patients with ovarian, breast, colon, and brain cancer. The OVCA BAD-pathway signature survival advantage was independent of surgical cytoreductive status. Conclusions. The BAD apoptosis pathway influences the sensitivity of human cancers to a variety of chemotherapies, likely via modulation of BAD-phosphorylation. The pathway has clinical relevance as a potential biomarker of therapeutic response, patient survival, and as a promising therapeutic target. Twenty-eight (28) advanced-stage serous epithelial ovarian cancers were resected at the time of primary surgery from patients who would receive platinum-based therapy. The tumors were arrayed on Affymetrix HG-U133A GeneChips. The samples were analyzed with respect to the BAD pathway for correlation to overall survival and cisplatin response.