Reversal effect of miR-155 on the resistance of leukemia cells to adriamycin by regulating Ets-1 expression

SHA Min; YE Jun; GUO Ting; ZHANG Lixin; LUAN Zhengyun

Abstract：Objective To detect the expression of miR?155 and Ets?1 in leukemia cell line K562 and adriamycin resistance K562/A02 cell line, and explore the relationship between miR?155, Ets?1 and drug resistance in leukemia treatment. Methods miR?155 simulation oligonucleotide probes and miR?155 inhibitor oligonucleotide probes, Ets?1 expression plasmid and Ets?1 interference expression plasmid were transfected in K562 and K562/A02 cells by Lipofectamine 2000. Real?time quantitative PCR was used to de?termine the expression of miR?155, Ets?1 and multidrug resistance( MDR1) . The protein levels of Ets?1 and MDR1 were analyzed by Western blotting. The viability of K562 and K562/A02 cells was evaluated by MTT assay. Results The expression levels of miR?155, Ets?1 and MDR1 were significantly increased in K562/A02 cells than those in K562 cells. Down?regulation of miR?155 could obviously increase the inhibition rate of adriamycin on K562/A02 cells and inhibit the expression of Ets?1 and MDR1, which could be reversed by overexpression of Ets?1. While, up?regulation of miR?155 could significantly increase the inhibition rate of adriamycin on K562 cells and stimulate the expression of Ets?1 and MDR1, which could be reversed by Ets?1 siRNA. Conclusion miR?155 is involved in the mechanism of drug resistance in leukemia by regulating Ets?1 expression, which may provide a potential novel target for overcoming drug?resistance.