A novel oncolytic adenovirus carrying human tumor necrosis factor-related apoptosis-inducing ligand gene induces hepatocellular carcinoma cell line apoptosis in vitro

AIM: To evaluate the efficiency of transgene expression and inducing apoptosis on tumor-specific replication-competent adenovirus carrying human tumor necrosis factor-related apoptosis-inducing ligand gene, a novel gene-viral therapeutic system CNHK500-hTRAIL, in hepatocellular carcinoma (HCC) cell lines in vitro.

METHODS: HCC cell lines HepG2, Hep3B and normal hepatocyte lines WRL-68 were transfected with CNHK500-hTRAIL. Virus replication assay was performed to evaluate the selective replication ability of CNHK500-hTRAIL. ELISA assay was used to detect the transgene expression of TRAIL. The cytotoxicity in cultured HCC and normal cells was evaluated by Methyl thiazolyl tetrazolium (MTT). Flow cytometry (FCM) was used to detect the early apoptotic induced by CNHK500-hTRAIL.

RESULTS: CNHK500-hTRAIL was selectively proliferated in the telomerase-positive HCC cell lines HepG2 and Hep3B. 72 hours after infection with CNHK500-hTRAIL, the expression of TRAIL in the supernatant of cultured cell lines HepG2 and Hep3B were 167.4 and 173.22 ng/L, respectively; CNHK500-hTRAIL killed more HepG2 and Hep3B cells significantly with MOI = 0.1 and induced obvious apoptosis but not in WRL-68 even with MOI = 50. The ability of transgene expression and inducing apoptosis were significantly stronger than that of replication-competent adenovirus CNHK500 or replication-defective Ad-hTRAIL.

CONCLUSION: Replication-competent adenovirus carrying human TRAIL gene is more effective than simplex oncolytic adenovirus or replication-defective adenovirus carrying human TRAIL gene in both cytotoxicity and efficiency of gene transfer in HCC, and holds great promise in the area of HCC therapy.