Abstract:

Abstract:Objective To investigate the effect of arsenic trioxide (ATO) on cellcycle progression of imatinib(IM)-resistant chronic myeloid leukemia (CML) cellline KBM5R with T315I point mutation,and provide theoretical foundation for overcoming resistance of CML patients to IM. Methods The wild-type cell line KBM5was selected as negative control of KBM5R with T315I point mutation，and the cells were divided into four groups according to ATO treatment：control group of KBM5R cells,ATO group of KBM5R cells,control group of KBM5 cells and ATO group of KBM5 cells. The proliferation of KBM5 and KBM5R cells after treated with IM or ATO were detected by MTT. The changes of cell cycles of KBM5 and KBM5R cells were quantified by flow cytometry. The expressions of P21 and P27 proteins in KBM5 and KBM5R cells after treated with ATO were determined by Western blotting. Results The IC50 of KBM5R cells treated with IM was higher than that of wild-type cell line KBM5 (P<0.01). The inhibitory rates of proliferation of KBM5 and KBM5R cells after treated with 0.5,1.0,2.0,4.0 and 8.0 μmol·L^-1 of ATO for 24,48,72 and 96 h were higher than that of control group,which were increased according to the increase of concentration or  the treatment time of  ATO （P<0.05）. The inhibitory effect of KBM5R cell oliferation was stronger than that of KBM5 at the same drug concentration and time （P<0.05）. The cell cycle detection of KBM5 and KBM5R cells after treated with 2.0,4.0 and 8.0 μmol·L^-1 ATO for 48 h showed that the G2/M arrest rate was increased according to the increase of concentration of ATO,and the G2/M arrest rate of KBM5R had no signficant difference compared with KBM5 at the same drug concentration. The expressions of P21 and P27 proteins in KBM5 and KBM5R cells after treated with 2.0,4.0 and 8.0 μmol·L^-1 ATO for 48 h were significantly increased in a concentration-depenent manner. Conclusion ATO can arrest cell cycle of KBM5R cell line in G2/M phase through up-regulation of P21 and P27 protein levels,and it is one of thereasons that ATO can inhibit the proliferation of KBM5R cells with T315I point mutation.

Key words: arsenic trioxide；imatinib-resistance；T315I point mutation；cell cycle