title: Radiation protective effect of hypoxia-inducible factor-1α (HIF-1α) on human oral squamous cell carcinoma cell lines.
abstract: We examined the effects of 5-Gy radiation on the expression of hypoxia-inducible factor-1α (HIF-1α) and the radiosensitivity of five human oral squamous cell carcinoma (OSCC) cell lines (SAS, Ca9-22, TT, BSC-OF and IS-FOM). In all of the cell lines, HIF-1α was expressed in mRNA, and radiation had no influence on gene transcription. The number of apoptotic cells increased 72 h after irradiation in cell lines SAS, Ca9-22 and TT cells, indicating low transcriptional levels of HIF-1α, and the levels of non-cleaved caspase-3, an executioner of apoptosis, and non-cleaved poly (adenosine diphosphate-ribose) polymerase (PARP), a marker of DNA damage early in apoptosis, decreased simultaneously. Conversely, radiation failed to induce apoptosis or to decrease expression of non-cleaved caspase-3 and PARP in cell lines BSC-OF and IS-FOM cells that expressed high levels of HIF-1α. BSC-OF and IS-FOM cells exhibited high migratory capacity. When CoCl(2) was present in the medium, HIF-1α expression increased along with the survival of Ca9-22 cells after radiation exposure. These results suggest that OSCC cells expressing high levels of HIF-1α are resistant to radiation. HIF-1α can be used to control the short-term radiosensitivity of cells.
authors.affiliation: Division of Medical Life Sciences, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 0.6-8564, Japan. hosokawa@cc.hirosaki-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Hosokawa
authors.forename: K
authors.initials: K
authors.lastname: Okumura
authors.forename: S
authors.initials: S
authors.lastname: Terashima
authors.forename: Y
authors.initials: Y
authors.lastname: Sakakura
mesh_terms: D017209:Apoptosis; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement; D002470:Cell Survival; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003720:Densitometry / Q000379:methods; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D009062:Mouth Neoplasms / Q000532:radiotherapy*; D011837:Radiation-Protective Agents; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors; D014158:Transcription, Genetic; D014965:X-Rays
chemical_list: D017077:Culture Media, Conditioned; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D011837:Radiation-Protective Agents