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miR-34在肿瘤发生发展中起着至关重要的作用,然而,mi R-34在肿瘤耐药中的作用研究不多。该研究将合成的mi R-34c成熟序列转染乳腺癌阿霉素(doxorubicin,DOX)耐药细胞MCF-7/DOX,探讨mi R-34c体外逆转MCF-7/DOX细胞耐药性作用及其可能的机制。采用Real-time RT-PCR检测mi R-34c在乳腺癌耐药细胞株MCF-7/DOX中的表达,MTS法检测miR-34c对MCF-7/DOX细胞阿霉素耐药性的影响,流式细胞术检测miR-34c对MCF-7/DOX细胞周期和凋亡的影响,Real-time RT-PCR和Western blot法检测多药耐药相关蛋白MDR、MRP以及细胞周期与凋亡相关蛋白Bcl-2、E2F3的表达。结果显示,mi R-34c在乳腺癌MCF-7/DOX耐药细胞中低表达,转染mi R-34c可明显增加耐药细胞对阿霉素的敏感性;流式分析发现,miR-34c可以促进耐药细胞G2期细胞周期阻滞和凋亡;与对照组相比较,miR-34c转染组细胞MDR、MRP蛋白表达无明显变化,而Bcl-2、E2F3 mRNA和蛋白表达均明显下调。研究表明,miR-34c直接靶向抑制Bcl-2和E2F3的表达,诱导细胞周期G2期阻滞和凋亡,进而增强MCF-7/DOX耐药细胞对阿霉素的敏感性。
miR-34 plays a crucial role in tumorigenesis. However, the role of miR-34 in tumor resistance has not been studied. In this study, miR-34c was transfected into doxorubicin (DOX) -resistant breast cancer cell line MCF-7 / DOX to explore the role of mi R-34c in reversing the drug resistance of MCF-7 / DOX cells in vitro. Its possible mechanism. The expression of mi R-34c in breast cancer cell line MCF-7 / DOX was detected by Real-time RT-PCR. The effect of miR-34c on doxorubicin resistance in MCF-7 / Flow cytometry was used to detect the effect of miR-34c on cell cycle and apoptosis in MCF-7 / DOX cells. Real-time RT-PCR and Western blot were used to detect MDR, MRP and cell cycle and apoptosis related proteins Bcl-2, E2F3 expression. The results showed that mi R-34c was overexpressed in breast cancer MCF-7 / DOX-resistant cells. The transfection of mi R-34c significantly increased the sensitivity of drug-resistant cells to doxorubicin. Flow cytometry analysis showed that miR-34c Compared with the control group, the expression of MDR and MRP protein in miR-34c transfected group did not change significantly, while the expression of Bcl-2, E2F3 mRNA and protein were significantly down-regulated . Studies have shown that miR-34c directly targets the expression of Bcl-2 and E2F3, induces cell cycle G2 arrest and apoptosis, and then enhances the susceptibility of MCF-7 / DOX-resistant cells to doxorubicin.