miR-26a通过调控E2F7、Myc抑制乳腺癌MDA-MB-231细胞的增殖和迁移能力

目的:研究miR-26a对乳腺癌MDA-MB-231细胞增殖和迁移能力的影响，并分析miR-26a 调控增殖与迁移的可能机制。方法:应用实时荧光定量PCR法(QPCR)检测乳腺癌细胞系和正常乳腺上皮细胞中miR-26a的表达水平，并检测三阴型乳腺癌组织及相应正常乳腺组织中miR-26a与E2F7 mRNA的表达水平。应用脂质体介导的方法，以miR-26a mimics与E2F7 siRNA瞬时转染MDA-MB-231细胞，实时荧光定量PCR法检测miR-26a表达水平，Western blot法检测E2F7、Myc蛋白的表达水平。MTT法检测MDA-MB-231细胞的增殖能力，划痕实验检测MDA-MB-231细胞迁移能力。结果:乳腺癌细胞中miR-26a的表达水平均低于正常乳腺细胞MCF-10A，且三阴型乳腺癌细胞表达水平降低最明显。三阴型乳腺癌组织中miR-26a相对于正常乳腺组织表达减低，而E2F7 mRNA表达则显著升高。miR-26a mimics转染后miR-26a表达水平显著升高，miR-26a过表达可抑制E2F7、Myc蛋白的表达；E2F7 siRNA转染后E2F7表达水平减低，Myc蛋白表达亦减低。MTT实验结果示miR-26a过表达可抑制MDA-MB-231细胞增殖，划痕实验示miR-26a过表达可抑制乳腺癌MDA-MB-231细胞迁移能力。结论:miR-26a可能通过抑制E2F7、Myc调控乳腺癌MDA-MB-231细胞的增殖与迁移能力。

The miR-26a inhibits proliferation and migration ability of MDA-MB-231 cells via regulation of E2F7 and Myc

Objective:To investigate the effect of miR-26a on proliferation and migration of breast cancer MDA-MB-231 cells，then to explore its possible mechanism.Methods:The miR-26a and E2F7 expression of breast cancer cell lines，normal breast epithelial cell，triple negative breast cancer tissues and adjacent normal breast tissues were detected by using Real-time PCR (QPCR).Transient transfection of miR-26a mimics and E2F7 siRNA to MDA-MB-231 cells were mediated by liposome.The miR-26a expression of MDA-MB-231 cell was detected by Real-time PCR，and the expression of E2F7 and Myc protein was detected by Western blot.The proliferation and migration ability were assessed by MTT and wound healing assay respectively.Results:The miR-26a levels of breast cancer cell lines were lower than that of normal breast cell MCF-10A，particularly triple negative breast cancer cell lines.Besides，the miR-26a expression of triple negative breast cancer tissues was inhibited compared to that of adjacent normal breast tissues，while the E2F7 mRNA expression was elevated significantly.The miR-26a expression of MDA-MB-231 cell was elevated significantly after miR-26a mimics transfection.The overexpression of miR-26a decreased the expression of E2F7 and Myc protein，and the knockdown of E2F7 also decreased the expression of Myc.The miR-26a inhibited the proliferation and migration ability of MDA-MB-231 cells according to MTT and wound healing assay results.Conclusion:The miR-26a inhibited proliferation and migration ability of MDA-MB-231 cells via possible mechanism of E2F7 and Myc repression.