A novel approach for inducing enhanced and selective transgene expression in hepatocellular-carcinoma cells.
Utility of the alpha-fetoprotein (afp) promoter for gene therapy against hepatocellular carcinoma (HCC) is limited because of the weak promoter activity. To circumvent this, the 5.1-kb 5;-flanking sequence of the human afp gene including the entire enhancer and silencer regions as well as the promoter region was employed for achieving strong, HCC-selective transgene expression. To thoroughly inhibit the promoter activity of the 5;-flanking sequence of the human afp gene, the afp 5;-flanking region was inserted downstream of the human interleukin-2 (il-2) gene controlled by the simian-virus-40 (SV40) early promoter. il-2-production ability of HCC cells transduced with the construct was significantly enhanced compared with that transduced with the same construct lacking the afp 5;-flanking region. Importantly, il-2 production of non-HCC cells was substantially inhibited by the addition of the afp 5;-flanking region to the construct. When the afp 5;-flanking region was inserted downstream of the human tumor-necrosis-factor-alpha (tnf-alpha) gene controlled by the retrovirus long-terminal-repeat (LTR) enhancer/promoter, tnf-alpha production ability of HCC cells was significantly enhanced and that of non-HCC cells was significantly suppressed compared with that transduced with the same construct lacking the afp 5;-flanking region. Our results indicated that the afp 5;-flanking region gave the enhanced HCC-selective activity to the non-tissue specific SV40 early promoter and LTR enhancer/promoter. It is essential for successful gene therapy to induce strong, target-cell-selective transgene expression. This novel strategy, therefore, may contribute to the establishment of HCC-selective cancer gene therapy.
Cao
G
G
Department of Microbiology, Second Military Medical University, Shanghai, People's Republic of China.
Kuriyama
S
S
Tsujinoue
H
H
Chen
Q
Q
Mitoro
A
A
Qi
Z
Z
D016475:3T3 Cells; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000628:therapy; D016207:Cytokines / Q000096:biosynthesis; D004742:Enhancer Elements, Genetic; D015972:Gene Expression Regulation, Neoplastic; D018014:Gene Transfer Techniques; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics; D008113:Liver Neoplasms / Q000235:genetics* / Q000628:therapy; D051379:Mice; D008979:Moloney murine leukemia virus / Q000235:genetics; D011401:Promoter Regions, Genetic; D012190:Retroviridae / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics; D020079:Terminal Repeat Sequences; D019076:Transgenes; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics; D000509:alpha-Fetoproteins / Q000096:biosynthesis / Q000235:genetics*
D016207:Cytokines; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D000509:alpha-Fetoproteins