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

摘要

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.%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 adja-cent 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.