[The target--gene expression of interleukin--12 in HepG2 cells]

EB virus vector pEBAF, which contains human alpha-fetoprotein gene promoter and enhancer was used as expression vector. Two recombinant expression vectors, pEBAF/P35 and pEBAF/P40, were constructed and co-transfected into 4 cell lines. RT-PCR suggested that both P35 and P40 mRNA are expressed in HepG2 cell secreting alpha-fetoprotein, in contrast, neither P35 mRNA nor P40m RNA was expressed in non-secreting alpha-fetoprotein cell lines. This proved that the pEBAF may lead to target--expression of IL-12 in hepatoma and has tissue specificity and exclusiveness for hepatoma. The cotransfected Hyg resistant clone of HepG2 cell was selected. Northern blot indicated that the HepG2 cell clone had transcription of P35 mRNA and P40 mRNA. Expression of IL-12 in the supernatant of HepG2 cell culture had been testified by ELISA and Western blot. IL-12 biological activity test indicated that the expressed IL-12 had activity of inducing IFN-gamma production. This research laid the foundation to develop an in vivo gene therapy strategy pointing to the treatment of hepatocellular carcinoma, with selective killing of the tumor cells and no effect on the normal hepatic cells.