Cell-specific expression of the analgesic-antitumor peptide coding sequence under the control of the human α-fetoprotein gene promoter and enhancer

The aim of the present study was to construct a gene-modified hepatocellular carcinoma (HCC)-specific analgesic-antitumor peptide (AGAP) expression vector regulated by the α-fetoprotein (AFP) promoter and enhancer, in order to evaluate its effect. The AFP promoter is generally used in HCC-specific gene therapy strategies. However, this approach is limited by the weak activity of the AFP promoter. Linking the AFP enhancer and promoter has been shown to generate a stronger and more HCC-selective promoter. The AGAP DNA fragment was amplified from the total RNA of the Chinese scorpion, Buthus martensii Karsch. The fragment was subsequently cloned into the pAFP plasmid with the minimal essential DNA fragment, which included the AFP gene promoter and enhancer, to construct the recombinant plasmid, pAFP-AGAP. The plasmid was transfected into HepG2 cells and the mRNA expression levels of AGAP were detected by reverse transcription polymerase chain reaction (RT-PCR). In addition, Cell Counting Kit 8 (CCK-8) was used to analyze the cytotoxicity of plasmid transfection. The length, position and orientation of the inserted AGAP gene were all confirmed to be correct; thus, the recombinant vector was successfully constructed. Using RT-PCR and CCK-8 analysis, the mRNA expression levels of AGAP and the cytotoxicity in AFP-producing human HCC cells were determined. The AFP promoter and enhancer were found to specifically accelerate the expression of the target genes within the cells that were positive for AFP. Therefore, the method used in the present study was demonstrated to be a novel integration of traditional Chinese medicine with western medicine.