Effects of TRAIL gene therapy on human hepatocellular carcinoma

Objective To evaluate the effects of TRAIL gene on the growth of human hepatocel- lular carcinoma (HCC) cells. Methods The cDNA encoding soluble human TRAIL was inserted into the expression vector pIRES-EGFP, then transferred into HepG2 and SMMC--7721 cells. TRAIL expression was detected by RT-PCR and western blot, and the cell growth inhibition and apoptosis were assessed by MTT and flow cytometry. Using nude mice subcutaneously hepatocellular carcinoma model, plasmid pIRES-EGFP-TRAIL gene was delivered into nude mice tumor by intratumoral injection. RT-PCR was adopted to detect the expression of TRAIL gene in tumor. The antitumoral efficacy of gene therapy was evaluated with tumor size. Results The eukaryon expression plasmid pIRES-EGFP-TRAIL was synthe- sized. This plasmid was transfected into HCC cells. TRAILmRNA expression was detected by RT-PCR, and the cellular protein was separated by SDS-PAGE. A weight of 19. 6×10~3 for sTRAIL monomers was predicted by Western blot. However, minimal cell death of HCC cells was observed upon transfection with pIRES-EGFP-TRAIL. Afer transfecting of TRAIL gene two weeks. the expression of TRAIL gene in nude mice tumor was all relatively strong, the expression of TRAIL gene in tissue near the tumor was weak and that in normal liver tissue was negative, but the tumor sizes were slightly less than those in con- trol group (P 0. 05). TRAIL gene intratumoral injection can lead to effective gene delivery and gene expression but limited effective to treat experimental nude mice HCC model. Conclusion HCC are insen- sitive towards TRAIL-mediated apoptosis, suggesting the presence of mediators that inhibit the TRAIL- inducing apoptosis pathway in HCC and a limited therapeutic role for TRAIL as a single agent in HCC.