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: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.
Project description:To determine the signaling networks that are dysregulated in platinum-resistant ovarian cancer, gene expression data were obtained from, and compared between, the ovarian cancer cell line, A2780, and its cisplatin-resistant derivative, A2780cis. Gene expression data from a cisplatin-sensitive ovarian cancer cell line (A2780) were collected and compared to gene expression data from a cisplatin-resistant cell line (A2780cis). 6 independent experiments were completed for both the sensitive and resistant cell lines.
Project description:Characterization of differential gene expression due to cisplatin resistance in human ovarian cancer spheroids by microarray analysis. In this dataset, we include the expression data obtained from cisplatin-sensitive and cisplatin-resistant human ovarian cancer spheroids. These data are used to obtain 1316 genes that are differentially expressed in response to cisplatin resistance.
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: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: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, and investigate the DNA methylation alterations associated with cisplatin resistance, we treated clonally derived, drug-sensitive A2780 epithelial ovarian cancer cells with increasing concentrations of cisplatin. After several cycles of drug selection, the isogenic drug-sensitive and -resistant pairs were subjected to global CGI methylation microarray analyses. We treated clonally derived, drug-sensitive A2780 epithelial ovarian cancer cells with increasing concentrations of cisplatin. After several cycles of drug selection, the isogenic drug-sensitive and -resistant pairs were subjected to global CGI methylation analyses by differential methylation hybridization (DMH) using a customed 44K promoter CGI microarray.