2009 Fiscal Year Final Research Report
Hypoxia induces resistance to 5-fluorouracil in oral cancer cells via G(1) phase cell cycle arrest.
| Project/Area Number |
20791546
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Surgical dentistry
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| Research Institution | Showa University |
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Principal Investigator |
UCHIDA Makiko Showa University, 歯学部, 助教 (20453631)
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| Co-Investigator(Renkei-kenkyūsha) |
葭葉 清香 , 員外助教
南雲 達人 , 員外助教
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| Project Period (FY) |
2008 – 2009
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| Keywords | 口腔癌 / 抗癌剤耐性 |
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| Research Abstract |
OSCC cells were divided to two groups by the proliferation activity under hypoxic condition; hypoxia-resistant (HR) and hypoxia-sensitive (HS) cells. Growth of HS cells were inhibited by hypoxia and introduced to G(1) arrest in cell cycle. 5-FU effect on HS cell viability was markedly reduced in hypoxic condition without an induction of chemoresistant related protein, P-glycoprotein. However, proliferation, cell cycle, and 5-FU sensitivity of HR cells were not affected by hypoxia. Hypoxia-inducible factor (HIF)-1alpha was induced by hypoxia in all OSCC cell lines, but diminished in HS cells within 48h. Expression of p21 and p27 was strongly augmented and CyclinD expression was reduced by hypoxia in HS cells. However, the expression of these proteins was constitutive in HR cells during 48h hypoxic culture. Phosphorylation of mammalian target of rapamycin (mTOR) was reduced by hypoxia in HS cells. From these findings, we concluded that HS OSCC cells acquire 5-FU resistance under hypoxia by G(1)/S transition through an upregulation of cell cycle inhibitors.
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