Hu Xiaolei, Huang Pingmei, Wang Jie, He Wan, Zhao Pan, Yao Guangyu, Ye Changsheng
Breast Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
Department of Clinical Nutrition, 458 Hospital of PLA, Guangzhou 510602, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2018 Jul 30;38(7):888-894. doi: 10.3969/j.issn.1673-4254.2018.07.20.
To investigate the role of miR- 433 in chemoresistance to docetaxel in breast cancer cells.
A docetaxel-resistant MCF-7 breast cancer cell line (MCF-7/DOX) was established by exposure of parental MCF-7 cells to progressively increased docetaxel concentrations. The functional role of miR-433 was investigated by assessing the changes in viability and apoptosis of the cells transfected with a miR-433 inhibitor or a miR-433 mimics. The downstream targets of miR- 433 were determined by bioinformatics analysis, cell transfection and luciferase reporter assay.
Quantitative real-time PCR analysis showed that miR- 433 was down-regulated in MCF-7/DOX cells. Transfection of the cells with the miR-433 inhibitor obviously enhanced chemoresistance to docetaxel and attenuated cell apoptosis in MCF-7 cells; miR-433 overexpression significantly increased the sensitivity to docetaxel and promoted apoptosis in MCF- 7/DOX cells. Luciferase reporter assay showed that the down-regulation miR-433 expression was associated with significantly increased expressions of Notch1 at both mRNA and protein levels in MCF-7 cells. Compared with the control cells, McF-7/DOX cells transfected with miR-433 mimics exhibited significantly decreased mRNA and protein expressions of Notch1.
miR-433 may reverse chemoresistance to docetaxel by targeting Notch1 in breast cancer cells.
探讨miR-433在乳腺癌细胞对多西他赛耐药中的作用。
通过将亲本MCF-7细胞暴露于逐渐增加的多西他赛浓度来建立多西他赛耐药的MCF-7乳腺癌细胞系（MCF-7/DOX）。通过评估用miR-433抑制剂或miR-433模拟物转染的细胞的活力和凋亡变化来研究miR-433的功能作用。通过生物信息学分析、细胞转染和荧光素酶报告基因测定来确定miR-433的下游靶点。
定量实时PCR分析表明，MCF-7/DOX细胞中miR-433表达下调。用miR-433抑制剂转染细胞明显增强了MCF-7细胞对多西他赛的耐药性并减弱了细胞凋亡；miR-433过表达显著增加了MCF-7/DOX细胞对多西他赛的敏感性并促进了细胞凋亡。荧光素酶报告基因测定表明，MCF-7细胞中miR-433表达下调与Notch1在mRNA和蛋白质水平的表达显著增加有关。与对照细胞相比，用miR-433模拟物转染的McF-7/DOX细胞Notch1的mRNA和蛋白质表达显著降低。
miR-433可能通过靶向Notch1逆转乳腺癌细胞对多西他赛的耐药性。
