Thermoradiotherapy in human head and neck squamous cell carcinoma cell lines.
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.
Asaumi
Jun-Ichi
J
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
Higuchi
Yuzuru
Y
Murakami
Jun
J
Kuroda
Masahiro
M
Shibuya
Koichi
K
Konouchi
Hironobu
H
Hisatomi
Miki
M
Matsuzaki
Hidenobu
H
Shigehara
Hiroshi
H
Kawasaki
Shoji
S
Kishi
Kanji
K
Hiraki
Yoshio
Y
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