An Association between the Radiation-Induced Arrest of G2-Phase Cells and Low-Dose Hyper-Radiosensitivity: A Plausible Underlying Mechanism?

Abstract

Marples, B., Wouters, B. G. and Joiner, M. C. An Association between the Radiation-Induced Arrest of G2-Phase Cells and Low-Dose Hyper-Radiosensitivity: A Plausible Underlying Mechanism? Radiat. Res. 160, 38–45 (2003). The survival of asynchronous and highly enriched G1-, S- and G2-phase populations of Chinese hamster V79 cells was measured after irradiation with 60Co γ rays (0.1–10 Gy) using a precise flow cytometry-based clonogenic survival assay. The high-dose survival responses demonstrated a conventional relationship, with G2-phase cells being the most radiosensitive and S-phase cells the most radioresistant. Below 1 Gy, distinct low-dose hyper-radiosensitivity (HRS) responses were observed for the asynchronous and G2-phase enriched cell populations, with no evidence of HRS in the G1- and S-phase populations. Modeling supports the conclusion that HRS in asynchronous V79 populations is explained entirely by the HRS response of G2-phase cells. An association was discovered between the occurren...