AIM: To study the effect of oxaliplatin on the survival rate of Y79 after down-regulation of Mcl-1 by SiRNA.

METHODS: Y79 cells were cultured in RPMI1640. The cultured cells were stimulated with 0.25μmol/L of oxaliplatin. The expression of Mcl-1 protein was detected by Western blot after 6, 16 and 24h respectively. Cells in logarithmic phase were collected and used for single-cell suspension. Then they were transfected with empty plasmid, Mcl-1-homo-991, Mcl-1-homo-1114 and Mcl-1-homo-1235. After 6h, fluorescence microscope was used to observe the transfection efficiency and the optimal one was selected. The cells were divided into Group A and transfected with empty plasmids. The cells transfected with Mcl-1 were divided into Group B and Group C. Group A and Group C were treated with 0.25μmol/L oxaliplatin for stimulating induction, and the apoptotic rate was compared after 24h.

RESULTS: The expression of Mcl-1 in Y79 stimulated by oxaliplatin was the most after 24h of culture. Mcl-1-homo-991 significantly inhibited the expression of Mcl-1 in Y79 after transfection. There was no significant difference in the apoptosis rate in Group A(11.1%±1.2%)and in the control group(6.1%±0.6%)(P>0.05). The apoptotic rate of Group C(49.2%±2.7%)was significantly higher than that of Group B(20.8%±1.9%). At the same time, the apoptotic rates of these two groups were significantly higher than those of Group A and control group, the difference was statistically significant(P<0.05).

CONCLUSION:Downregulation of Mcl-1 by siRNA can reduce the drug resistance of Y79, thereby enhancing the apoptosis of Y79, and reducing the survival rate of Y79.