Effects of silencing c-myc gene by siRNA on Jiyoye cell growth and apoptosis

Objective To explore the effect of suppressing c-myc gene expression by lentiviral vector-based siRNA on the proliferation and apoptosis of Jiyoye cells,and provide experimental evidence for novel therapeutic approaches for leukemia and malignant lymphoma by targeting c-myc gene.Methods One short hairpin RNA(siRNA) interference sequence targeting c-myc gene(c-myc-3) and one negative control sequence(c-myc-neg) were designed and synthesized.They were annealed and cloned into pLVX vector to produce the recombinant plasmid,which was then transfected into Jiyoye cells by lentivirus.72-hour after transfection,the transfection rate in each group was detected by flow cytometry(FCM).The cell proliferation activities were assayed by MTT,and the apoptosis was analyzed by flow cytometry with Annexin V/PI double staining.Results ①72-hour after transfection,no significant difference in terms of positive cell rates and mean fluorescence intensity was observed between each group(P 0.05),indicated that the transfection efficiency of each group was not significantly different.②During the 168 hours after transfection,the cells transfected with c-myc-3 all grew more slowly as compared with the cells in the negative control group and blank group,and the differences were statistically significant(P 0.05).72-hour after being tranfected with c-myc-3,the cell inhibition ratio in the experimental group was significantly higher than that in the negative control group and blank control group(P 0.05).③72-hour after transfection with pLVXc-myc-3,the proportion of apoptotic cells in the experimental group was(25.6 ± 4.2) %,and that in the negative control group and blank control group was(15.1 ± 4.2) % and(12.7 ± 1.8) %,respectively.The proportion of early-term apoptotic cells in the experimental group was significantly higher than that in the negative control group and blank control group(P 0.05).The proportion of late-term apoptotic cells in the experimental group was(11.5 ± 4.7) %,and that in the negative control group and blank control group was(9.3 ± 4.7) % and(8.4 ± 2.8) %,respectively.The proportion of late-term apoptostic cells in the experimental group was significantly higher than that in the negative control group and blank control group(P 0.05).Conclusion It is demonstrated that the siRNA targeting cmyc inhibited tumor cell proliferation and induced cell apoptosis,which further provided an experimental basis for c-myc gene silencing in targeted therapy of leukemia and lymphoma.