SUMO-1 enhancing the p53-induced HepG2 cell apoptosis.

In order to investigate the effect of small ubiquitin-like modifier-1 (SUMO-1) on the p53-induced HepG2 cell apoptosis, HepG2 cells were transfected by recombinant plasmids as pwtp53, pMDM2 and pSUMO-1 respectively. Western blot was employed to detect the protein expression of the transfected recombinant plasmids and the rate of apoptosis was measured by flow cytometry. The results showed that in cells transfected with pwtp53 and pwtp53 + pSUMO-1, the apoptosis rate was (16.79+/-1.62) % and (18.15+/-1.36) % respectively, while transfected with pwtp53+ pMDM2, the rate was decreased to (5.17+/-1.23) %. The apoptosis rate was (14.06+/-1.84) % in the cells transfected with pwtp53+pMDM2+pSUMO-1, significantly higher than that in the cells Transfected with pwtp53+pMDM2 (P<0.01). The apoptosis rates in the cells were all less than 2 % and had no significant difference among the groups. It was suggested that in the HepG2 cells, SUMO-1 can increase the apoptosis induced by wild-type p53 through binding to p53 protein, posttranslational modification and inhibiting the p53 degradation by MDM2.