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MicroRNA-133b targets glutathione S-transferase ? expression to increase ovarian cancer cell sensitivity to chemotherapy drugs.

ABSTRACT: Accumulating studies reveal that aberrant microRNA (miRNA) expression can affect the development of chemotherapy drug resistance by modulating the expression of relevant target proteins. The aim of this study was to investigate the role of miR-133b in the development of drug resistance in ovarian cancer cells.We examined the levels of miR-133b expression in ovarian carcinoma tissues and the human ovarian carcinoma cell lines (A2780, A2780/DDP and A2780/Taxol, respectively). We determined the cell viability of these cell lines treated with cisplatin or paclitaxel in the presence or absence of miR-133b or anti-miR-133b transfection using the MTT assay. Reverse transcription polymerase chain reaction and Western blotting were used to assess the mRNA and protein expression levels of two drug-resistance-related genes: glutathione S-transferase (GST)-? and multidrug resistance protein 1 (MDR1). The dual-luciferase reporter assay was used to detect the promoter activity of GST-? in the presence and absence of miR-133b.The expression of miR-133b was significantly lower in primary resistant ovarian carcinomas than in the chemotherapy-sensitive carcinomas (P<0.05), and the same results were found in primary resistant ovarian cell lines (A2780/Taxol and A2780/DDP) compared to the chemotherapy-sensitive cell line (A2780; P<0.05). Following miR-133b transfection, four cell lines showed increased sensitivity to paclitaxel and cisplatin, while anti-miR-133b transfection reduced cell sensitivity to paclitaxel and cisplatin. Dual-luciferase reporter assay showed that miR-133b interacted with the 3'-untranslated region of GST-?. Compared to controls, the mRNA and protein levels of MDR1 and GST-? were downregulated after miR-133b transfection and upregulated after anti-miR-133b transfection.MicroRNA-133b may reduce ovarian cancer drug resistance by silencing the expression of the drug-resistance-related proteins, GST-? and MDR1. In future, the combination of miR-133b with chemotherapy agents may prevent the development of drug resistance in ovarian cancers.

SUBMITTER: Chen S

PROVIDER: S-EPMC4577257 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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MicroRNA-133b targets glutathione S-transferase π expression to increase ovarian cancer cell sensitivity to chemotherapy drugs.

Chen Shuo S Jiao Jin-Wen JW Sun Kai-Xuan KX Zong Zhi-Hong ZH Zhao Yang Y

Drug design, development and therapy 20150916

<h4>Background</h4>Accumulating studies reveal that aberrant microRNA (miRNA) expression can affect the development of chemotherapy drug resistance by modulating the expression of relevant target proteins. The aim of this study was to investigate the role of miR-133b in the development of drug resistance in ovarian cancer cells.<h4>Methods</h4>We examined the levels of miR-133b expression in ovarian carcinoma tissues and the human ovarian carcinoma cell lines (A2780, A2780/DDP and A2780/Taxol, r ...[more]

PMID: 26396496

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Project description:BackgroundHepatocellular carcinoma (HCC) remains a major public health problem worldwide. The identification of effective chemotherapeutic targets for advanced HCC patients is urgently required. In this study, we investigated the role of protein phosphatase 2A-B55δ subunit (PP2A-B55δ, encoded by the PPP2R2D gene) and related mechanisms affecting chemotherapy sensitivity of HCC.MethodsExperimental approaches for measuring the levels of PPP2R2D mRNA and B55δ protein in HCC included bioinformatics analyses, quantitative real-time polymerase chain reaction (qRT-PCR), western blotting (WB), immunofluorescence and immunohistochemistry assays. Cell cycle, migration, colony formation, apoptosis, and cell proliferation assays in stable PPP2R2D-knockdown and -overexpression cell lines in vitro, and tumorigenicity assays in vivo, were performed to explore the function of B55δ in cisplatin (cDDP) chemotherapy of HCC. Bioinformatics prediction, luciferase reporter assays, qRT-PCR, WB, and cell cycle analyses were used to reveal the regulatory relationship between microRNA-133b (miR-133b) and PPP2R2D expression. miR-133b mimic and inhibitor were used to elucidate the regulatory mechanism.ResultsOur studies showed that PPP2R2D expression was down-regulated in both HCC tumors and HCC cell lines. Treatment with cDDP increased the amount of B55δ protein. Artificially increasing the expression of B55δ counteracted cyclin-dependent kinase 1 activation, modulated transitions of the cell cycle, and increased the suppressive effect of cDDP on cell migration, colony formation, apoptosis, and proliferation in vitro and tumor growth in vivo, thus enhancing therapeutic efficiency. In contrast, knockdown of B55δ partially inhibited the effect of cDDP chemotherapy. miR-133b was shown to regulate PPP2R2D expression by binding to the 3'-untranslated region of PPP2R2D mRNA. The miR-133b/PPP2R2D signaling pathway affects the effectiveness of cDDP chemotherapy.ConclusionsPP2A-B55δ, regulated by miR-133b, enhances the sensitivity of HCC to cDDP chemotherapy. Our data indicate that PP2A-B55δ might be a novel and attractive target for increasing chemotherapy sensitivity of HCC.

Project description:BackgroundGlutathione (GSH) is one of the most important agents of the antioxidant defense system of the cell because, in conjunction with the enzymes glutathione peroxidase (GSH-Px) and glutathione S transferase pi (GSTpi), it plays a central role in the detoxification and biotransformation of chemotherapeutic drugs. This study evaluated the expression of GSH and the GSH-Px and GSTpi enzymes by immunohistochemistry in 30 canine mammary tumors, relating the clinicopathological parameters, clinical outcome and survival of the bitches. In an in vitro study, the expression of the genes glutamate cysteine ligase (GCLC) and glutathione synthetase (GSS) that synthesize GSH and GSH-Px gene were verified by qPCR and subjected to treatment with doxorubicin, to check the resistance of cancer cells to chemotherapy.ResultsThe immunohistochemical expression of GSH, GSH-Px and GSTpi was compared with the clinical and pathological characteristics and the clinical outcome in the bitches, including metastasis and death.The results showed that high immunoexpression of GSH was correlated to the absence of tumor ulceration and was present in dogs without metastasis (P < 0.05). There was significant correlation of survival with the increase of GSH (P < 0.05). The expression of the GSH-Px and GSTpi enzymes showed no statistically significant correlation with the analyzed variables (p > 0.05). The analysis of the relative expression of genes responsible for the synthesis of GSH (GCLC and GSS) and GSH-Px by quantitative PCR was done with cultured cells of 10 tumor fragments from dogs with mammary tumors.The culture cells showed a decrease in GCLC and GSS expression when compared with no treated cells (P < 0.05). High GSH immunoexpression was associated with better clinical outcomes.ConclusionTherefore, high expression of the GSH seems to play an important role in the clinical outcome of patients with mammary tumors and suggest its use as prognostic marker. The in vitro doxorubicin treatment significantly reduces the expression of GCLC and GSS genes so we can consider them to be candidates for predictive markers of therapeutic response in mammary cancer.

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MicroRNA-133b targets glutathione S-transferase ? expression to increase ovarian cancer cell sensitivity to chemotherapy drugs.

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MicroRNA-133b targets glutathione S-transferase π expression to increase ovarian cancer cell sensitivity to chemotherapy drugs.

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