miR-27b在雌激素受体阳性的乳腺癌细胞上皮间质转化及他莫昔芬耐药中的调控机制

Regulation mechanism of miR-27b in epithelial-to-mesenchymal transition and Tamoxifen sensitivity of ER positive breast cancer cells

目的探讨mi R-27b在雌激素受体(ER)阳性的乳腺癌细胞上皮间质转化及他莫昔芬耐药中的调控机制。方法通过反转录实时定量PCR测定mi R-27b的表达。用双荧光素酶报告和蛋白质印迹实验验证mi R-27b对HMGB3的靶向调控作用。在他莫昔芬敏感(Tam S)或耐药(Tam R)的MCF-7细胞中过表达mi R-27b或敲减HMGB3后测定细胞活力,分析上皮和间质标志物的表达,检测细胞侵袭力。结果 Tam R MCF-7细胞中mi R-27b的水平约为Tam S MCF-7细胞的20%。过表达mi R-27b增加了4-羟基他莫昔芬(4-OHT)对Tam R MCF-7细胞的活力抑制。Tam S与Tam R细胞在mi R-27b过表达后,穿膜细胞数目均明显减少。在Tam R MCF-7细胞中,转染mi R-27b mimics增加了约3倍的E-cadherin表达,同时也降低了约70%的N-cadherin表达。mi R-27b可以结合预测的HMGB3 3′非翻译区(UTR)结合位点并降低HMGB3在蛋白水平的表达。HMGB3敲减和mi R-27b过表达具有类似的生物学功能。结论 mi R-27b可以通过抑制HMGB3的表达抑制乳腺癌细胞上皮间质转化并增强乳腺癌细胞他莫昔芬敏感性。

Objective To investigate regulation mechanism of miR-27b in epithelial-to-mesenchymal transition and Tamoxifen sensitivity of ER positive breast cancer cells. Methods qRT-PCR was performed to detect miR-27b expression. Dual luciferase assay and Western blot assay were performed to detect the regulative effect of miR-27b on HMGB3 expression. Tamoxifen sensitive （TamS）and tamoxifen resistant （TataR） MCF-7 cells were transfected with miR-27b mimics or HMGB3 siRNA. Then cell viability, the expression of epithelial and mesenchymal markers and cell invasion were measured.Results TamR MCF-7 had approximately 20% of miR-27b expression compared to TamS MCF-7 celiA, miR-27b overexpression significantly enhanced the suppressive effect of 4-hydroxytamoxifen on cell viability in TamR MCF-7 Cells, miR-27b overexpression significantly inhibited cell invasion in both TamS and TataR cells. In TamR MCF-7 cells, t, ransfection of miR-27b mimics resulted in approximately 3 folds increase of E-cadherin and 70% decrease of N-cadherin. miR-27b could bind to the predicted binding site in the 3＇UTR of HMGB3 and decrease HMGB3 expression at protein level, Knockdown of HMGB3 phenocopied the effects of miR-27b. Conclusion miR-27b can inhibit epithelial-to-mesenchymal：transition and sensitize ER positive breast cancer cells to tamoxifen via targeting HMGB3.