OBJECTIVETo find a new method of treating hepatocellular carcinoma with melittin by way of using the melittin gene.

METHODSThe recombinant adenoviruses carrying the melittin gene and alpha-fetoprotein (AFP) promoter (Ad-rAFP-Mel) were constructed through a bacterial homologous recombinant system. The efficiency of the adenovirus mediated gene transfer and the inhibition effect of Ad-rAFP-Mel on the proliferation of hepatocarcinoma cells were determined by X-gal staining and MTT assay respectively. The tumorigenicity of hepatocarcinoma cells transfected by Ad-rAFP-Mel and the antitumor effect of Ad-rAFP-Mel on the transplanted tumors in nude mice were detected in vivo.

RESULTSThe mRNA of the melittin gene was transcripted in HepG2 hepatocellular carcinoma cells transducted by Ad-rAFP-Mel. The efficiency of adenovirus mediated gene transfered to BEL-7402 hepatocarcinoma cells was 100% when the multiplicities of infection (MOI) of Ad-rAFP-Mel was 10 in vitro and was high in vivo as well. The inhibitive rates of Ad-rAFP-Mel and Ad-rAFP for BEL7402 cells were 66.2%+/-2.7% and 2.9%+/-2.3% (t = 30.83) by MTT assay. The inhibitive rates of Ad-CMV-Mel for BEL7402, SMMC7721 and L02 cells were 58.9%+/-9.6%, 65.9%+/-3.8%, 31.7%+/-1.2%, respectively, and those of the Ad-rAFP-Mel were 6.2%+/-2.7%, 16.1%+/-6.6%, 7.5%+/-3.3%, respectively (t = 1.27; t = 11.31, and t = 12.12, vs. Ad-CMV-Mel group in same cells). The tumorigenicity rates of hepatocarcinoma cells transfected by Ad-rAFP-Mel were decreased. A significant antineoplastic effect was detectd on transplanted tumor in nude mice by intratumoral injection of Ad-rAFP-Mel.

CONCLUSIONAd-rAFP-Mel can inhibit specifically the proliferation of AFP-producing human hepatocarcinoma cells in vitro and in vivo. It suggests that animal toxin gene can be used as an interesting antitumor gene.