Inhibitory effect of recombinant adenovirus carrying melittin gene on hepatocellular carcinoma

Abstract

ObjectivesTo search for a new clinical application of melittin (Mel): treating hepatocellular carcinoma with Mel gene. MethodsRecombinant adenoviruses carrying the Mel gene and α-fetoprotein (AFP) promoter (Ad-rAFP-Mel) were constructed through a bacterial homologous recombinant system. The efficiency of adenovirus-mediated gene transfer and the inhibitory effect of Ad-rAFP-Mel on the proliferation of hepatocarcinoma cells were determined by X-gal stain and MTT assay, respectively. The tumorigenicity of hepatocarcinoma cells transfected by Ad-rAFP-Mel and the antitumor effect of Ad-rAFP-Mel on transplanted tumor in nude mice were detected in vivo. ResultsThe Mel mRNA was transcribed in BEL-7402 hepatocellular carcinoma cells transducted by Ad-rAFP-Mel. The efficiency of adenovirus-mediated gene transferred to BEL-7402 cells was 100% when the multiplicity of infection of Ad-rAFP-Mel was 10 in vitro, and was also high in vivo. 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, P=6.6×10−6) 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% and 31.7±1.2%, respectively, and of Ad-rAFP-Mel were 66.2±2.7%, 16.1±6.6% and 7.5±3.3%, respectively (t=1.27, P=0.27; t=11.31, P=3.5×10−4; and t=12.12, P=2.7×10−4 versus the Ad-CMV-Mel group in the same cells). The tumorigenicity rates of hepatocarcinoma cells transfected by Ad-rAFP-Mel were decreased. A significant antineoplastic effect was detected on transplanted tumor in nude mice by intratumoral injection of Ad-rAFP-Mel. ConclusionsAd-rAFP-Mel can inhibit specifically proliferation of AFP-producing human hepatocarcinoma cells in vitro and in vivo. This suggests that animal toxin gene can be used as an antitumor gene.