Document Detail


Hypoxia induces resistance to 5-fluorouracil in oral cancer cells via G(1) phase cell cycle arrest.
MedLine Citation:
PMID:  18710819     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Malignant tumors are exposed to various levels of hypoxic condition in vivo. It has been known that tumor cells under hypoxia are resistant to chemotherapies. To clarify the mechanism of the hypoxia-induced chemoresistance, we evaluated the effects of hypoxia on the resistance of oral squamous cell carcinoma (OSCC) cell lines to 5-fluorouracil (5-FU). 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.
Authors:
Sayaka Yoshiba; Daisuke Ito; Tatsuhito Nagumo; Tatsuo Shirota; Masashi Hatori; Satoru Shintani
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-08-16
Journal Detail:
Title:  Oral oncology     Volume:  45     ISSN:  1368-8375     ISO Abbreviation:  Oral Oncol.     Publication Date:  2009 Feb 
Date Detail:
Created Date:  2009-01-28     Completed Date:  2009-11-23     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9709118     Medline TA:  Oral Oncol     Country:  England    
Other Details:
Languages:  eng     Pagination:  109-15     Citation Subset:  IM    
Affiliation:
Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Kitasenzoku 2-1-1, Ohta-ku, Tokyo 145-8515, Japan. yoshiba@senzoku.showa-u.ac.jp
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MeSH Terms
Descriptor/Qualifier:
Antineoplastic Agents / pharmacology*
Blotting, Western
Carcinoma, Squamous Cell / drug therapy*,  metabolism
Cell Cycle / drug effects,  physiology
Cell Hypoxia / physiology*
Cell Line, Tumor / drug effects,  metabolism
Cell Proliferation / drug effects
Cyclin D / metabolism
Drug Resistance, Neoplasm / physiology*
Fluorouracil / pharmacology*
G1 Phase / drug effects,  physiology
Humans
Mouth Neoplasms / drug therapy*,  metabolism
Transcription Factors / metabolism
Chemical
Reg. No./Substance:
0/Antineoplastic Agents; 0/Cyclin D; 0/Transcription Factors; 51-21-8/Fluorouracil

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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