| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2011: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2010: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2009: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Research Abstract |
Biliary cancers are highly malignant diseases with poor prognosis and thus development of new treatments such as gene therapy is necessary. Although adenovirus vectors are widely used for cancer gene therapy, conventional adenoviral vectors infect not only cancer cells but also normal cells. Therefore, a new method that allow more specific gene delivery to cancer cells needs to be developed to obtain more efficient anti-tumor effect and safety. We explored methods of retargeting adenovirus vectors for targeted gene therapy of human biliary cancers using the Ad incorporating an IgG Fc binding motif (Z33) from the Staphylococcus protein A (Ad-FZ33) combined with tumor specific antibodies. Flow cytometry analysis revealed high expression levels of epithelial cell adhesion molecule (EpCAM) and epidermal growth factor receptor (EGFR) on human biliary cancer cells. Ad-FZ33 expressing LacZ combined with antibodies against EpCAM or EGFR, followed by β-gal assay, demonstrated highly efficient gene transduction in these biliary cancer cells, compared with the treatment with control antibody or without antibody. Ad-FZ33 expressing uracil phosphoribosyl transferase (UPRT), an enzyme which greatly enhances the toxicity of 5-fluorouracil (FU), combined with antibodies against EpCAM or EGFR, remarkably enhanced the sensitivity of biliary cancer cells to 5-FU. By contrast, the treatment didn't affect 5-FU sensitivity of the cells not expressing EpCAM or EGFR including normal hepatocytes. Finally, treatments with the UPRT-expressing Ad-FZ33 with antibodies against EpCAM or EGFR, followed by 5-FU administration, were significantly suppressed the growth of biliary cancer xenografts in nude mice. These results indicate that the molecular target genechemotherapy mediated by the Z33 fiber-modified adenovirus with anti-EpCAM or anti-EGFR antibodies offers a potentially effective therapeutic modality against biliary cancers, and can be expected in clinical applications fairly.
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