Antitumor effects of interleukin-18 gene-modified hepatocyte cell line on implanted liver carcinoma.

OBJECTIVE

To investigate the antitumor effects of intrasplenically transplanted interleukin-18 (IL-18) gene-modified hepatocytes on murine implanted liver carcinoma.

METHODS

Embryonic murine hepatocyte cell line (BNL-CL2) was transfected with a recombinant adenovirus encoding IL-18 and used as delivery cells for IL-18 gene transfer. Two cell lines, BNL-LacZ and BNL-CL2, were used as controls. One week after intrasplenic injection of C26 cells (colon carcinoma line), tumor-bearing syngeneic mice underwent the intrasplenic transplantation of IL-18 gene-modified hepatocyte cell line and were divided into treatment group (BNL IL-18) and control groups (BNL-LacZ and BNL-CL2). Two weeks later, the serum levels of IL-18, interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) in the implanted liver carcinoma-bearing mice were assayed, the cytotoxicity of murine splenic cytotoxic T-lymphocytes (CTLs) was measured, and the morphology of the hepatic tumors was studied to evaluate the antitumor effects of the approach.

RESULTS

In the treatment group, the serum levels of IL-18, IFN-gamma, TNF-alpha and NO increased significantly. The splenic CTL activity increased markedly (P < 0.01), accompanied by a substantial decrease in tumor volume and the percentage of tumor area and prolonged survival of liver carcinomo-being mice.

CONCLUSIONS

In vivo IL-18 expression by ex vivo manipulated cells with IL-18 recombinant adenovirus is able to exert potent antitumor effects by inducing a predominantly T-cell-helper type 1 (Th1) immune response. Intrasplenic transplantation of adenovirus-mediated IL-18 gene-modified hepatocytes could be used as a targeting treatment for implanted liver carcinoma.