Interferon-α gene therapy prevents aflatoxin and carbon tetrachloride promoted hepatic carcinogenesis in rats

Retrovirus-mediated interferon α (IFN-α) gene transfer was evaluated with regard to its possible protective effects against aflatoxin B1 (AFB1)-initiated and carbon tetrachloride (CCl4)-promoted hepatic carcinogenesis in rats. To our knowledge, this is the first time an experimental in vivo gene therapy trial was conducted in Egypt. Two genes were examined in liver tissue by RT-PCR: the first was glutathione-S-transferase placental (GST-P) isoenzyme, as an early marker to detect hepatic malignancy; the second was IFN-α gene expression to detect the efficiency of gene uptake and its persistence after transduction. Forty male rats, divided equally into 4 groups, were included in the study: the first group was the control; the second group received CCl4 0.2 ml subcutaneously twice weekly for 12 weeks and AFB1 0.25 mg/kg body wt intraperitoneally twice weekly for 6 weeks; the third group received IFN-α (108 pfu) intravenously in the tail vein prior to the start of CCl4 and AFB1 injections; and the fourth group received IFN-α (108 pfu) by intrahepatic injection under ultrasonography guide after termination of the CCl4 and AFB1 injection schedule. The results showed that IFN-α has a marked and significant protective effect against hepatic fibrogenesis as well as hepatic carcinogenesis. Pathological examination of liver tissue proved that IFN-α minimized both fibrotic and cirrhotic processes. The amount of fibrosis was less in both groups receiving IFN-α, with more protection in the group that received IFN-α intravenously prior to CCl4 and AFB1. The results of RT-PCR showed that the IFN-α gene was significantly expressed in both groups receiving IFN-α, with a more intense expression in the group that received IFN-α by intrahepatic injection after termination of CCl4 and AFB1 injections. The IFN-α gene was detected after three months of gene transduction in rats receiving IFN-α intravenously prior to CCl4 and AFB1 and after one month of gene transduction in the post CCl4 and AFB1 rats. IFN-α gene was not expressed in the two groups that did not undergo gene transfer. Histopathological signs of premalignant macronodules were evident in the group receiving CCl4 and AFB1, but not IFN-α as well as in the group that received IFN-α at the end of the experiment. GST-P gene expression was also detected in these two groups, confirming early malignant transformation. In conclusion, IFN-α exerts significant protective effects, but more so when the gene is administered before fibrogenic and carcinogenic induction in hepatic tissues. IFN-α gene therapy may be justified in clinical trials for high-risk candidates with hepatic carcinogenesis.