Objective: To investigate the effects of E2F-1 gene silencing on the chemosensitivity of human gastric cancer SGC-7901/DDP cells to cisplatin and explore the underlying mechanism.
Methods: Gastric cancer SGC-7901/DDP cells were transfected with the recombinant lentivirirus vector Lv-shRNA-E2F-1 for E2F-1 gene silencing, with cells transfected with the control recombinant lentivirirus vector Lv-shRNA-NC as the negative control. MTT assay was used to evaluate cisplatin chemosensitivity of the cells, and the cell apoptosis rate and cell cycle distribution were detected by flow cytometry. The mRNA and protein expressions of E2F-1 and apoptosis-related genes (survivin and Bcl-2) were detected by RT-PCR and Western blotting.
Results: MTT assay showed that the IC50 of cisplatin was significantly lowered in Lv-shRNA-E2F-1-transfected cells compared with the negative and blank control cells (P<0.05). Lv-shRNA-E2F-1 transfection caused significant cell cycle arrest in G0/G1 phase and induced obvious cell apoptosis. Compared with Lv-shRNA-NC group and the blank control group, Lv-shRNA-E2F-1 group showed significantly lowered expressions of E2F-1 mRNA by 45.0% and 41.3% and E2F-1 protein by 66.7% and 70.5%, survivin mRNA by 30.3% and 28.7% and survivin protein by 56.5% and 53.6%, and Bcl-2 mRNA by 76.6% and 76.8% and Bcl-2 protein by 74.6% and 79.9%, respectively. No significant difference was found in the measurements between Lv-shRNA-NC group and the blank control group (P>0.05).
Conclusion: E2F-1 gene silencing can enhance cisplatin chemosensitivity of gastric cancer SGC-7901/DDP cells possibly by down-regulating survivin and Bcl-2 expressions, suggesting the value of E2F-1 as a new chemotherapeutic target for gastric cancer.