The EIIAPA Chimeric Promoter for Tumor Specific Gene Therapy of Hepatoma

Abstract

For targeted imaging and therapy of hepatocellular carcinoma (HCC), we established a chimeric promoter (EIIAPA) containing alpha-fetoprotein (AFP) promoter and hepatitis B virus enhancer II (EIIA) to control downstream expression of reporter and therapeutic genes. We combined AFP promoter and EIIA to establish a chimeric EIIAPA promoter, then developed a bi-cistronic plasmid vector containing HSV1-tk and luciferase genes controlled by EIIAPA to stably transfect HCC cells. The selective transcriptional activity of EIIAPA was assayed by bioluminescence imaging (BLI) and the function of EIIAPA was determined by in vivo microPET and BLI. The luciferase expression driven by EIIAPA was higher than that driven by AFP promoter in HCC cell lines. EIIAPA-tk induced cytotoxicity was observed only in HepG2 cells. Accumulation of ¹³¹I-FIAU and bioluminescent signal were detected on HepG2 tumors but not in parental tumors. The HepG2 tumors derived from lentiviral-transduced EIIAPA-tk expressing cells accumulated ¹²⁴I-FIAU whereas the ARO tumors did not. The transfected HepG2 tumors expressed adequate EIIAPA-controlled HSV1-TK and the tumor regressed after ganciclovir treatment. The chimeric EIIAPA is a potential candidate promoter for targeted imaging and gene therapy of HCC.