[Antitumor effects of soluble TRAIL in human hepatocellular carcinoma]

Abstract

Objective: To investigate therapeutic potential of soluble TRAIL (sTRAIL) in hepatocellular carcinoma (HCC).

Methods: Expression of TRAILR was determined by in situ hybridization in 60 samples of resected hepatocellular carcinoma, 20 samples of normal liver tissue near the margin of benign tumor and 2 HCC cell lines of HepG2 and SMMC-7721. The clinical data of the patients were analyzed as well as cellular effects of sTRAIL in promoting apoptosis on HCC cell lines HepG2 and SMMC-7721 (p53 gene mutated) after exposure to different concentrations of recombinant protein.

Results: High death receptor (DR) expression and low DcR expression in HCC tissue differed from low DR expression and high DcR expression in the normal hepatic tissue with statistical significance. DR5, DR4, and DcR2 but not DcR1 were expressed in both cell lines. The expression of DR was closely correlated with HCC differentiation, with the weak expression in poor differentiation. The positive rate of DR expression in 32 cases of grade III-IV was significantly lower than that in 28 cases of grade I-II (P < 0.05). Cell apoptosis rates were 10%, 70% and 50% of HCC cells, Jurkat cells and human cholangiocarcinoma cell line QBC939 24 h after recombinant of TRAIL alone.

Conclusion: TRAILR expression is prevalent in HCC, with different receptor types existing. HCC is resistant to TRAIL-mediated apoptosis. The treatment of TRAIL alone only has a limited effect on inducing apoptosis on HCC cell lines of HepG2 and SMMC-7721.