1999 Fiscal Year Final Research Report Summary
A new strategy for the therapy of pancreatic cancer by proton pump inhibitor agents
| Project/Area Number |
09671290
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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 |
Digestive surgery
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| Research Institution | Kanazawa University |
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Principal Investigator |
OHTA Testuo Kanazawa University, School of Medicine, Associate Professor, 医学部, 助教授 (40194170)
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| Co-Investigator(Kenkyū-buntansha) |
KAYAHARA Masato Kanazawa University, School of Medicine, Assistant Professor, 医学部, 講師 (60224705)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Bafilomycin A / Pancretic cancer / Colon cancer / Apoptosis / Vacuolar type proton pump |
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| Research Abstract |
The effect of bafilomycin A1 on tumor growth in vitro and in vivo was examined using an MTT assay and an in vivo tumor model. Five pancretic cancer cell lines seven colon cancer cell lines were used in this study. The ID 5 0 of bafilomycin A1 by the MTT assay was from 5 nM to 40 nM in every cell lines. Phosphatidylserine externalization of cancer cells was found 24 hr after bafilomycin A1 treatment. In DNA analysis, a ladder of fragmented DNA was detected 48 hr after bafilomycin A1 treatment. Morphologically, cancer cells showed cytoplasmic blebbing and a decreased number of microvilli 24 hr after the treatment, and the characteristic morphological changes of apoptosis, including nuclear chromatin condensation and fragmentation, loss of microvilli and cell shrinkage, were observed 48 hr after the treatment. Caspase 3 and caspase 9 proteins were activated 48 hr after treatment, however, caspase 6 and caspase 7 proteins were not activated during the treatment by Western blotting, suggesting a mitochondria-dependent apoptotic pathway. These apoptotic changes were not inhibited by 10 mM imidazole treatment. Next, nude mice bearing a xenografted Capan-1 cell line tumor received 4 weeks of bafilomycin A1 (1.0 mg/kg/day). This treatment significantly inhibited tumor growth compared with controls after 21 days. 25C-prodigiosin also showed the same inhibitory effect on a xenografted Capan-1 cell line tumor. Histopathological examination of tumor cells in the treatment group demonstrated signs of apoptosis with chromatin condensation and cell shrinkage. These observations suggest that bafilomycin A1 inhibits the growth of human colon and pancreatic cancer cells through apoptosis.
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