Abstract
Lethal Sectoring, Genomic Instability, and Delayed Division Delay in HeLa S3 Cells Surviving Alpha- or X-irradiation*Hiroshi SASAKI Dept. Exp. Radiol., Kyushu Univ. Lethal sectoring is the process for survival in which lethal damage remaining in irradiated cells is eliminated as offspring without reproductive integrity. This process occurs through the postirradiation 1st to 4th divisions with the accompanying appearance of a clonogenic progenitor. The features of lethal sectoring and delayed cell death were explored by analyzing the pedigrees of HeLa cells surviving alpha- (0.45 Gy) or X-irradiation (3 Gy) (20% survival dose). Most (ca.70%) of the lethal damage was eliminated from alpha-particle survivors through the 1st to 2nd divisions, but it persisted in X-ray survivors until the 2nd generation. Nonlethal damage remaining in the clonogenic progenitors led to an elevated incidence of delayed cell death in their progeny. The mean incidence was higher for alpha-particle (16.3%) than X-ray survivors (8.3%), indicating the greater potentiality for genomic instability (GI) by alpha-particles. Misrepaired clustered DNA damage by alpha-particles and unrepaired PLD by X-rays seemed to be involved in the induction of GI. Delayed division delay (DDD) was noticed, though occasionally (ca.10% per cell), with the progeny during the postirradiation 1st-3rd generations. Mean DDD was much longer in alpha- (ca.11 h) than X-irradiated cells (ca.4 h). Supposedly DDD was triggered by delayed chromosome breakage (published in JRR 45: 497-508 [2004]).
