Clonogenicity of the Progeny of Surviving Cells after Irradiation

Abstract

The clonogenic potential of the progeny of irradiated cells was tested in vitro by replating irradiated cultures after various times, allowing between five and over 25 subsequent divisions to take place after irradiation. Whereas the plating efficiency of surviving Chinese hamster cells was not decreased, in C3H10T1/2 cells a dose-dependent but slight decrease in plating efficiency was observed even after the longest follow-up period. These data do not contradict the prevalent hypothesis in radiobiology that the proliferation potential of a clonogenic cell surviving after irradiation is not significantly different from that of a non-irradiated cell.

Re. Clonogenicity of the Progeny of Surviving Cells after Irradiation, by R. Born and K. R. Trott (1988)

“…This is because cells that have undergone the requisite five to eight doublings which are needed to be counted as survivors may in fact ultimately succumb to the late expression of lethal effects of radiation . We were therefore very interested in the paper by Born and Trott (1988) recently published in the International Journal of Radiation Biology, in which they refer to our earlier studies . In trying to rebutt our arguments, however, the authors were guilty of selective commentary on their data, which was obviously beset by severe methodological problems .…”

“…Figure la shows just such a case . The shouldered survival curve was drawn from the conventional C3H survival data of table 3 (Born and Trott, 1988) . In the Born and Trott protocol, cells set up at the same time were subcultured on day 35 after irradiation, then allowed to grow to confluence over 21 days, and subcultured again to allow reassessment of plating efficiency .…”

Relevance of Non-Targeted Effects for Radiotherapy and Diagnostic Radiology; A Historical and Conceptual Analysis of Key Players

“…Soon after the first publications in recent times relating to lethal mutations, genomic instability, delayed death or bystander effects, now known collectively as non-targeted effects or NTE [11,23,24,25,26,126], there was controversy in the literature and many reports of failure to find these unexpected consequences in non-irradiated cells or progeny of irradiated cells [127,128]. The initial confusion resolved somewhat when it was realised that all cell types did not show these effects [129,130] and that experimental conditions needed to be carefully controlled [131].…”

Ionizing Radiation and Human Health: Reviewing Models of Exposure and Mechanisms of Cellular Damage. An Epigenetic Perspective

“…The awareness has therefore begun to emerge that the cells that survived after exposure to IR, despite being apparently normal, could accumulate damages. In fact, scientists found that the irradiated cells could not go beyond the 7–10 divisions (instead of the normal 60–70) and, above all, that some mutations and lethal events become evident only in the progeny of irradiated cells [ 16 ]. Some researchers began to theorize the progressive accumulation of mutations and chromosomal aberrations and to envisage the idea of critically rethinking the thesis, utterly implausible, of the absolute normality of the irradiated survived cells [ 17 ].…”