| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2002: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 2001: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Endostatin (ES), a carboxyl-terminal fragment of type XVIII collagen, which shows a strong anti-angiogenic activity, has been introduced to several clinical studies. Opposite to the initial expectation, the efficacy of ES is inconsistent, suggesting more detail investigations using animal model are required. The purpose of this study is to determine the effect of ES gene transfer on in vivo tumor growth in a murine model. A ung cancer cell line, Lewis Lung Carcinoma (LLC), was transfected with ES gene to, express and secrete ES by lipofectin. After clones were selected to secrete ES by ELISA, several stable transfectants with ES gene (LLC/ES) and control transfectants (LLC/mock) were established. In vitro proliferation using MTT assay of these transfectants demonstrated similar growing speed. In contrast to previous reports, in vivo subcutaneous tumorignecity of LLC/ES transfectants are significantly greater than that of LLC/mock transfectants. Immunohistochemical staining analysis using anti-CD31 antibody demonstrated that ES gene transfer induced angiogenesis, suggesting coinduction of another gene implicated in neovascularization. As expected, LLC/ES transfectants secreted not only ES but also vascular endothelial growth factor (VEGF) to much greater than LLC/mock transfectants. Interestingly, culture supernatants of LLC/ES cells enhanced in vitro proliferation of human umbilical vein endothelial cells (HUVEC) to much greater than those of LLC/mock cells. These results indicate that ES gene transfer in murine lung carcinoma cells induces VEGE secretion, resulting in enhanced in vivo tumorigenecity in a murine model. More attention should be paid for ES gene therapy into lung cancer cells because it may affect other genes expression, which upregulates angiogenesis.
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