ABSTRACT
Colon cancer is one of the common malignant tumors of digestive system.In our previous study, it has been demonstrated that colon cancer specific antigen thioredoxin like-2b (Txl-2b) can interact with Ras-related nuclear protein (Ran).However, there are few reports about the role and mechanism of Ran in tumorigenesis of colon cancer.Aims: To investigate the effect of Ran-targeting RNA interference on apoptosis and expressions of caspase-3 and poly(ADP-ribose) polymerase (PARP) in colon cancer cell lines.Methods: 20, 40 and 60 nmol/L siRNA-1 (si-1 group), siRNA-2 (si-2 group), siRNA-3 (si-3 group) targeting to Ran gene and normal control siRNA (NC group) were transfected into colon cancer cell line HCT116 and DLD-1, respectively.The interference efficiency of siRNAs and expressions of caspase-3 and PARP were detected by Western blotting.Cell apoptosis was determined by flow cytometry.Results: 20 nmol/L siRNA-1 and siRNA-2 had the best effect on inhibiting expression of Ran.Early apoptosis rates of HCT116 and DLD-1 cells in si-1 group were significantly higher than those in NC group (19.37%±7.57% vs.4.83%±1.72%;16.53%±3.38% vs.6.27%±3.13%;P all <0.05).Late apoptosis rates of HCT116 and DLD-1 cells in si-1 and si-2 groups were significantly higher than those in NC group (15.97%±3.31%, 16.33%±5.40% vs.6.40%±1.05%;22.93%±1.57%, 11.50%±0.70% vs.6.20%±0.98%;P all <0.05).Compared with NC group, expressions of cleaved caspase-3 (active form) and cleaved PARP (inactive form) were significantly increased in DLD-1 cells of si-1 and si-2 groups.Conclusions: Silencing Ran gene can significantly promote the apoptosis of colon cancer cells, and its mechanism is related to the regulation of caspase-3 and PARP expression.