| Project/Area Number |
14571156
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General surgery
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| Research Institution | KEIO UNIVERSITY |
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Principal Investigator |
JINNO Hiromitsu Keio University, School of Medicine, Instructor, 医学部, 助手 (20216261)
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| Co-Investigator(Kenkyū-buntansha) |
ASAGA Sota Keio University, School of Medicine, Assistant, 医学部, 助手 (00327529)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2003: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2002: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Epidermal Growth Factor / Eosinophilic Cationic Protein / Targeting Therapy / Breast Cancer / Endogenous Protein / ECP / EGF / targeting therapy / ターゲッティング療法 |
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| Research Abstract |
Epidermal growth factor receptor (EGFR) overexpression has been found in 30% of breast cancer patients anti is associated with a poor clinical prognosis. Such cases are highly aggressive and resistant to conventional treatment including surgery and chemoendocrine therapies. To selectively kill highly proliferating cancer cells with EGFR overexpression, targeted therapies aiming at EGFR have been developed. However, clinical application of targeted therapies would entail several major problems, because they are usually composed of plant toxin, bacterial toxin, or marine monoclonal antibodies. In an attempt to reduce immunogenicity and toxicity of the targeted therapy, we have developed the conjugate consisting of human endogeneous proteins. Recombinant human eosinophil cationic protein (ECP) was chemically conjugated to recombinant human EGF via a disulfide bond using the heterobifunctional reagent N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP) and 2-iminothiolane. The cytotoxic activity of the conjugate was evaluated by MTT assay against EGFR-overexpressing breast cancer cell lines (BT-20, MCF-7) as well as EGFR-negative small cell lung cancer cell line (H69). EGF-ECP conjugate revealed dose-dependent cytotoxicity for EGFR-overexpressing BT-20 breast cancer cells with an IC_<50> of 1.5x10^<-7>M and had no effect on EGFR-negative H69 cells. Recombinant human ECP alone had an IC_<50> of higher than 10^<-5>M. A mixture of flee ECP and EGF showed no more cytotoxic activity than ECP alone. Addition of excess EGF in the medium protected EGFR-overexpressing cells from the cytotoxic activity of the conjugate. The cytotoxic potential of the conjugate was positively correlated with cell's EGFR number. These results suggest that EGF-ECP conjugate may be effective against EGFR-overexpressing breast cancers with less iminunogenicity than conventional targeted therapies.
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