c-Myc silencing impedes cell proliferation and enhances cytotoxicity of cisplatin in non-small cell lung cancer

We investigated the expression of c-Myc in non-small cell lung cancer (NSCLC) tissues and explored the effect of c-Myc silencing on cell proliferation and cisplatin cytotoxicity. mRNA expression levels of c-Myc in 84 NSCLC tissue samples and corresponding para-cancerous tissues were detected by real-time PCR. c-Myc small interfering RNA (siRNA) was transfected into NSCLC H1299 cells by Lipofectamine 2000. Real-time PCR was carried out to validate the transfection efficiency. Cell Counting Kit-8 was used to evaluate cell proliferation. Cisplatin toxicity experiments using CCK-8 assays showed cytotoxicity of cisplatin plus c-Myc gene silencing in NSCLC cells. The c-Myc mRNA level in NSCLC tissues was significantly higher than that in corresponding para-cancerous tissues (P < 0.05). c-Myc siRNA was successfully transfected into H1299 cells. The proliferation rates of H1299 cells after c-Myc silencing at 24, 48 and 72 h were lower than those of control groups (P < 0.05). The combination of c-Myc silencing and cisplatin had the most cytotoxic effect on H1299 cells compared with individual and control groups (P < 0.05). c-Myc may act as an oncogene in NSCLC and could be a potential target for NSCLC gene therapy.