Recombinant human adenovirus P53 enhances radiosensitivity of human hepatocellular carcinoma in vitro

Objective:To investigate the inhibitory effect of recombinant human adenovirus P53(rAd-P53) against human hepatocellular carcinoma cell lines with different P53 statuses and its enhancing effect on radiosensitivity.Methods:Two human hepatocellular carcinoma cell lines with different P53 genetic statuses,PLC/PRF/5(MT P53) and SMMC-7721(WT P53) were infected with recombinant adenovirus carrying wild-type P53 gene(rAd-P53) with increasing multiplicities of infection(MOI).P53 protein expression was detected by Western blotting assay;cell survival was evaluated by MTT;radiosensitivity was evaluated using a clonogenic assay;and cell apoptosis was assayed by TUNEL.Results:Infection efficiency of 50 MOI values of rAd-P53 to PLC/PRF/5 and SMMC-7721 cells were 89.37% and 86.53%,respectively.The expression of P53 protein was significantly increased in both cell lines 48 h after infection,and cell survival rates of PLC/PRF/5 and SMMC-7721 cells were 3.41% and 35.44%,respectively.Inhibitory rates of PLC/PRF/5 and SMMC-7721 cells 5 d after infection were 41.91% and 17.03%,respectively.Cells were treated with rAd-P53 at 20 MOI for 48 h and then cells were irradiated(4 Gy);the apoptotic rates in PLC/PRF/5 and SMMC-7721 cells were(26.9±5.6)% and(16.4±2.9),respectively(P0.01).Clone formation assay showed that rAd-P53 enhanced sensitivity of PLC/PRF/5 and SMMC-7721 cells to radiotherapy,and SER(sensitive enhancement ratio) of Dq were 1.30 and 1.16,respectively,and SER of D0 were 1.57 and 1.25,respectively.Conclusion:rAd-P53 can greatly inhibit proliferation,induce l apoptosis and increase radiosensitivity of human hepatocellular carcinoma cells.But the aforesaid efficacy of rAd-P53 in PLC/PRF/5 cells is stronger that in SMMC-7721 cells,which suggests that hepatocellular carcinoma cells with different P53 statuses responds differently to treatment with rAd-P53 or combination of rAd-P53 and irradiation.