Abstract
The current use of targeted radiotherapy in the treatment of neuroblastoma has generated a requirement for further information on the radiobiology of these cells. Here we report on studies of the dose-rate effect in two human neuroblastoma cell lines (HX138 and HX142) and the recovery that they demonstrate in split-dose experiments. The sensitivity of the two cell lines to high dose-rate irradiation was confirmed. Surviving fractions at 2 Gy were 0.083 for HX138 and 0.11 for HX142. There was little evidence of a dose-rate effect above 2 cGy min-1 but significant sparing was seen at lower dose rates. Substantial recovery was seen in split-dose experiments on both cell lines, to an extent that was consistent with the linear quadratic equation. The data were used to derive values for the beta parameter of the linear-quadratic equation; the values for the neuroblastomas were higher than for any of the other human tumour cell lines that we have investigated to date. Thus, despite their high sensitivity to ionising radiation HX138 and HX142 do exhibit substantial levels of cellular recovery, suggesting that they may have a significant capacity for repair of radiation-induced lesions.
Highlights
The two cell lines used here, HX138 and HX142 were established from xenografted tumour tissue by Dr J.M
In the case of HX138 the data are indistinguishable from a pure exponential curve and in HX142 there is evidence for curvature in the semi-logarithmic plot
The high radiosensitivity of cell lines derived from human neuroblastoma has been demonstrated in previous studies (Ohnuma et al, 1977; Deacon et al, 1985) it was not seen in the work of Weichselbaum et al (1980)
Summary
The two cell lines used here, HX138 and HX142 were established from xenografted tumour tissue by Dr J.M. The two cell lines used here, HX138 and HX142 were established from xenografted tumour tissue by Dr J.M Deacon in this department (Deacon, 1987). Cell survival assays were carried out according to the soft agar colony method of Courtenay and Mills (1978). Single-cell suspensions were prepared from stock cultures by enzymatic digestion (trypsin 0.05%: EDTA 0.02%). Serial dilutions were made on the basis of haemocytometer counts. One ml aliquots of a mixture of 2 volumes tumour cell suspension, I volume August Rat red blood cells (diluted 1:8 and irradiated to a dose of approximately 200 Gy), I volume letha-lly irradiated tumour cells and 6 volumes 0.5% warm agar (Difco) were pipetted into round-bottomed culture
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
