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Archive > Volume 24 Issue 4 > 2017,24(4):380-388. DOI:10.3872/j.issn.1007-385X.2017.04.008 Prev Next
Basic Research
Med19knockdown promotes chemosensitivity of breast cancer cells and its possible mechanism
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Abstract:
Objective:To explore the effect and molecular mechanism of mediator 19 (Med19) on drug sensitivity of breast cancer cells. Methods: Human breast cancer cell line MCF-7/ADM (adriamycin resistant) and it’s parental cell line MCF-7（NC groups） were selected. Lentivirus-mediated RNA-interference was used to construct MCF-7/ADM and MCF-7 cell lines that stably expressing low Med19 (KD groups), and the infection efficiency was detected by Real-time PCR and Western blotting assays. The change of drug-susceptibility to ADM, cisplatin (DDP) and taxinol (TAX) were examined with CCK-8 assay before and after Med19 knockdown. The effects of Med19 knockdown on the expressions of multidrug resistance gene 1(MDR1), Bcl2, Bax, Caspase-3 and active caspase-3 in breast cancer cells were detected by RT-PCR and Western Blotting assays, respectively. Effect of Med19 down-regulation and ADM treatment on apoptosis rates of MCF-7 and MCF-7/ADM cells were detected with flow cytometry assay. Results: Compared with MCF-7 cells, MCF-7/ADM cells exhibited drug resistance to ADM, DDP and TAX. MCF-7/ADM and MCF-7 cell lines that stably expressing low Med19level were successfully established; their drug-susceptibilities to ADM, DDP, TAX were increased, and the IC50 values of these three cytotoxic agents deceased obviously (all P<0.05). The mRNA and protein expressions of Med19 in MCF-7/ADM cells were significantly higher than those in MCF-7 cells, however, Med19 knockdown significantly inhibited the expressions of MDR1 mRNA and protein in MCF-7/ADM cells (all P<0.05); in addition, it significantly increased the expressions of active caspase-3 and Bax protein in both MCF-7/ADM and MCF-7 cells (all P<0.05) and decreased the expression of Bcl2 protein (all P<0.05). Besides, compared with NC or NC+ADM group, the apoptosis rate of the cells significantly increased in KD group or KD+ADM group (all P<0.05). Conclusions: High Med19 expression plays a particularly important role in chemoresistance of breast cancer, and the mechanism might correlate with Med19 regulating MDR1 expression and affecting apoptosis related genes.
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Project Supported:
Project supported by the National Natural Science Foundation of China (No.81472485), and the Project of the Wuxi Health and Family Planning Commission (No.Q201615, YGZXM14038,YGZXQ1311)
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