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Xi Gu, Jian-Yi Li, Jiao Guo, Pi-Song Li, Wen-Hai Zhang
(Department of Breast Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China (mainland))
Med Sci Monit 2015; 21:3291-3297
This study aimed to investigate the potential influence of microRNA-451 (miR-451) in drug resistances of the Paclitaxel-resistant breast cancer cell line by transfecting miR-451 mimics and miR-451 inhibitors to MCE-7, MCF-7/EPI, and MCF-7/DOC.
MATERIAL AND METHODS: Real-time quantitative PCR (qRT-PCR) was performed for detecting whether transfected miR-451 mimics and miR-451 inhibitors could regulate the expression of miR-451 effectively. The apoptosis of the 3 cell lines was measured by applying Annexin V-APC/PI staining. Western blot was used for the detection of the protein expression of Bcl-2 and Caspase 3 after the transfection of miR-451 mimics /inhibitors. Bioinformatics analysis demonstrated that Bcl-2 protein is a potential target gene for miR-451.
RESULTS: In comparison to the control group, after transfection with miR-451 mimics, there was a significant increase in miR-451 expression in MCF-7, MCF-7/EPI, and MCF-7/DOC. Cells in the three cell lines had increased apoptosis, Bcl-2 protein expression decreased significantly, and Caspase protein expression increased obviously. After the transfection with miR-451 inhibitors, miR-451 expression was significantly decreased and apoptosis in the 3 cell lines had no significant decrease compared with the control group.
CONCLUSIONS: Increased miR-451 expression may negatively regulate Bcl-2 mRNA and protein expression, followed by affecting the protein expression of caspase 3, and accelerate the apoptosis in breast cancer, indicating that miR-451 might influence the drug resistances of the Paclitaxel-resistant breast cancer cell line.
Keywords: Antineoplastic Agents, Phytogenic - chemistry, Breast Neoplasms - genetics, Caspase 3 - metabolism, Cell Line, Tumor - drug effects, DNA Primers, Drug Resistance, Multiple - genetics, Drug Resistance, Neoplasm - genetics, Gene Expression Regulation, Neoplastic, MCF-7 Cells - drug effects, MicroRNAs - metabolism, Paclitaxel - chemistry, Proto-Oncogene Proteins c-bcl-2 - metabolism, Up-Regulation