title: Adenovirus-mediated tissue-specific cytosine deaminase gene therapy for human hepatocellular carcinoma with different AFP expression levels.
abstract: To evaluate whether in vitro and in vivo transferring of Escherichia coli cytosine deaminase gene to a solid tumor will confer the sensitivity to the prodrug 5-fluorocytosine (5FC) on these cells, we constructed two replication-defective adenovirus vector in which the cytosine deaminase gene was driven by CAG promoter (Adex1CACD) and AFP gene 5'-flanking region (Adex1AFPCD), respectively. By transferring these two vectors to SMMC7721AFP(-) and HepG2 human hepatocellular carcinoma (HCC) cells in vitro, we found that Adex1CACD vector could effectively suppress SMMC7721AFP(-) and HepG2 cells growing in the presence of 5FC even if the infected cell is less to 20%, while Adex1AFPCD vector only conferred HepG2 cells sensitivity to 5FC. When Adex1CACD was directly injected into established subcutaneous SMMC7721AFP(-) tumors in nude mice receiving 5FC, the tumor growth was inhibited significantly, which was consistent with those in vitro results. Furthermore, the Adex1AFPCD plus 5FC suppressed SMMC7721AFP(+) tumor growth in vivo, but not SMMC7721AFP(-) tumor. The results suggested that the CAG promoter-controlled CD gene could effectively mediate the growth inhibition in different kinds of HCC combined with administration of 5FC, and the AFP promoter-controlled CD gene could only suppress the HCCs expressing high levels of AFP. Therefore, adenovirus-mediated tumor-specific gene transfer may be a potential strategy for local control of tumor growth.
authors.affiliation: Department of Immunology, Second Military Medical University, 800 Xiang Yin Road, Shanghai 200433, P.R. China.
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.forename: Weiping
authors.initials: W
authors.lastname: Zhang
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Wakimoto
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hamada
authors.forename: Xuetao
authors.initials: X
authors.lastname: Cao
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000628:therapy*; D043525:Cytosine Deaminase; D005260:Female; D005437:Flucytosine / Q000627:therapeutic use; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D009700:Nucleoside Deaminases / Q000235:genetics*; D009928:Organ Specificity; D014162:Transfection; D014407:Tumor Cells, Cultured; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D000509:alpha-Fetoproteins; D005437:Flucytosine; D009700:Nucleoside Deaminases; D043525:Cytosine Deaminase