1997 Fiscal Year Final Research Report Summary
Development of a gene therapy vector bearing a swiching mechanism of gene expression
| Project/Area Number |
08557142
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Human genetics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SAITO Izumu University of Tokyo, Institute of Medical Science, Associate Professor, 医科学研究所, 助教授 (70158913)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAKI Toshiyuki Kyoto University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (70293909)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Hepatocarcinoma / Gene therapy / Vector / Adenovirus / AFP promoter |
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| Research Abstract |
To develop tissue-specific and efficient expression system applicable for specific gene therapy, we newly constructed a recombinant adenovirus expressing Cre driven by the afetoprotein promoter (AFPp), as a hepatocarcinoma-specific molecular switch in this system. HepG2 and HeLa cells were co-infected with the "AFPp-Cre virus" and an "expression target virus" bearing an Cre-switching ON/OFF expression unit. In AFP-producing HepG2 cells, the LacZ gene expression level is about two-hundred-fold higher than that in HeLa cells. Furthermore, in HepG2 cells the double-infection system shows about fifty-fold higher expression in vitro than the conventional direct-expression system under control of the AFP promoter. To examine where the double infection method is useful also in in vivo applications, we analyzed LacZ gene expression in hepatocellular carcinoma grown in the liver of nude mice following inoculation of HuH7 hepatocellular carcinoma cells through the splenic route. After the injection of the viral mixture of CALNLNZ virus and AFPp-Cre virus through the tail vein, Lacz expression was observed in about 10-15% of cells of the disseminated liver tumors formed. No LacZ expression was detected in the nomal liver tossue. The result showed that a sigificant expression was observed in disseminated tumors by intravenous injection and that the specificty was strictly maintained in vivo. Moreover, we happened to find an HuH7 tumor in the lung as well as in the liver. The lung tumor was also stained similarly to the tumor in the liver. The observation suggest that the double infection method might be effective for gene therapy of hepatocellular carcinoma of disseminated and metastatic tumors.
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