靶向ABCG2的RNA干扰逆转乳腺癌球囊细胞化疗耐药的研究

Objective 　To investigate the effect of RNA interference targeting ABCG2 gene to reverse chemotherapy resistance of mamosphere cell of breast cancer. Methods ABCG2-siRNA sequence was designed and inserted into lentiviral vector. Then we packaged virus and established a stable ABCG2-silenced MCF-7 mamosphere cell lines. The expression level of ABCG2 was detected by Western blot; MTT test was applied to measure the inhibition rate. Flow cytometry was performed to assess the cell cycle and apoptotic rate. Results Western Blot showed that ABCG2 was highly expressed in the mamosphere cells, as the RNAi silenced ABCG2, the expression decreased concurrently. MTT results showed that inhibition rate of MCF-7 adherent cells was higher than mamosphere cells of MCF-7 in the role of 5-Fu, and the inhibition rate increased as the concentration of 5-FU increased in ABCG2-silenced mamosphere cells. Flow cytometry showed that most mamosphere cells were in G0/G1 phase. The rate of cells in G0/G1 phase went up and apoptotic rate rose significantly since the 5-Fu concentration increased or the ABCG2 gene silenced. Conclusion ABCG2 protein was highly expressed in breast cancer mamosphere cell. And the resistance for 5-Fu in mamosphere cell was stronger than the MCF-7 cells. The inhibition of ABCG2 gene expression could sinificantly increase the cells inhibition rate and the apoptosis rate in mamosphere cell, and reverse its resistence to 5-Fu.?????