title: Thermoradiotherapy in human head and neck squamous cell carcinoma cell lines.
abstract: Thermoradiosensitivity of 8 cell lines of head and neck squamous cell carcinoma (HO-1-u-1, HSC2, HSC3, HSC4, SAS, KB, Hep2, and Ca9-22) was investigated. The differences of radiosensitivity between the cell line with the highest radiosensitivity and the cell line with the lowest radiosensitivity were 1.7-, 7.7-, and 41-fold at 2, 6 and 8 Gy, respectively. The differences between the cell line with the highest thermosensitivity and the cell line with the lowest thermosensitivity were 2.4-, 6.2- and 34.4-fold at 43 degrees C for 40, 60 and 100 min, and 2.6-, 4.9- and 127-fold at 44 degrees C for 20, 30 and 50 min, respectively. These findings indicated that there were large differences in both radiosensitivity and thermosensitivity among the 8 cell lines. There was a negative relationship between radiosensitivity and thermosensitivity (43 degrees C: r=-0.600, 44 degrees C: r=-0.848) in 7 of 8 cell lines, the exception being the HSC4 cell line, which was resistant to both therapies. Four of the 8 cell lines at 43 degrees C and 5 at 44 degrees C in the radiotherapy combined with thermotherapy showed actual survival rates smaller than the theoretical survival rates. Thus, thermoradiotherapy was deemed effective in the head and neck carcinoma cell lines, although 1 of 8 cell lines was resistant to both radiotherapy and thermotherapy.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Field of Tumor Biology, Graduate School of Medicine and Dentistry, Okayama University, Japan. asaumi@md.okayama-u.ac.jp
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Asaumi
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Higuchi
authors.forename: Jun
authors.initials: J
authors.lastname: Murakami
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kuroda
authors.forename: Koichi
authors.initials: K
authors.lastname: Shibuya
authors.forename: Hironobu
authors.initials: H
authors.lastname: Konouchi
authors.forename: Miki
authors.initials: M
authors.lastname: Hisatomi
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Matsuzaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shigehara
authors.forename: Shoji
authors.initials: S
authors.lastname: Kawasaki
authors.forename: Kanji
authors.initials: K
authors.lastname: Kishi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hiraki
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy* / Q000628:therapy*; D002470:Cell Survival; D004307:Dose-Response Relationship, Radiation; D006258:Head and Neck Neoplasms / Q000532:radiotherapy* / Q000628:therapy*; D006801:Humans; D006979:Hyperthermia, Induced; D013696:Temperature; D013997:Time Factors; D014407:Tumor Cells, Cultured