The relationship between radiosensitivity and cell kinetic effects after low- and high-dose-rate irradiation in five human tumors in nude mice.
Radiation-induced synchronization of cells in the radiosensitive G2 phase can, theoretically, be applied to individual tailoring of fractionation schemes, possibly rendering radiotherapy more effective. For that purpose, cell cycle perturbations were studied in five xenografts by flow cytometry. A dose-dependent increase of cells in G2 phase was noticed in all five tumor cell lines after high-dose-rate irradiation, and in four tumor cell lines after low-dose-rate irradiation. The timing of maximum accumulation was not related to dose, but coincided with the cell cycle time of the respective tumors. Furthermore, the increase in the number of cells in G2 phase correlated with the radiosensitivity of the tumors as assessed by measurements of regrowth delays. The observed synchronization provides a basis for further investigations on the relevance of radiation-induced cell cycle synchrony to the effectiveness of fractionated radiotherapy.
van Oostrum
I E
IE
Institute of Radiotherapy, University Hospital Utrecht, The Netherlands.
Erkens-Schulze
S
S
Petterson
M
M
Wils
I S
IS
Rutgers
D H
DH
D000230:Adenocarcinoma / Q000503:physiopathology / Q000532:radiotherapy; D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000503:physiopathology / Q000532:radiotherapy; D002453:Cell Cycle; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000503:physiopathology / Q000532:radiotherapy*; D011836:Radiation Tolerance; D011879:Radiotherapy Dosage; D014183:Transplantation, Heterologous; D002583:Uterine Cervical Neoplasms / Q000503:physiopathology / Q000532:radiotherapy; D014846:Vulvar Neoplasms / Q000503:physiopathology / Q000532:radiotherapy