The proliferative status and clonogenic capacity of tumour cells in a transplantable rhabdomyosarcoma of the rat before and after irradiation with 800 rad of X-rays
article
R-1 rhabdomyosarcomas transplantable in the inbred strain of WAG/Rij rats were labelled semicontinuously with 3H-TdR and subsequently irradiated with X-rays in order to estimate the rate of recruitment of Q into P cells and to obtain more insight into the importance of hypoxia with respect to the P and Q status of clonogenic cells. Labeling was performed by giving animals from one to a total number of up to 7 intraperitoneal injections with 3H-TdR within 30 hr. Half of the number of tumors received an acute dose of 800 rad of 300 kV X-rays at 45 min after completion of the last labeling in order to reduce the fraction of well oxygenated cells among the surviving clonogenic cells to less than 1%; labeled control tumors were sham irradiated. Fractions of labeled tumor cells, LI(tumor), were evaluated from autoradiographs prepared from sections of tumors that were fixed 15 min after irradiation; fractions of labeled cell foci, LI(fo), were determined in autoradiographs prepared from cultures of cells isolated from the remaining parts of the tumors. Analysis of the variation in LI(tumor) as a function of time and of the number of injections showed that the rate of recruitment of Q cells into P cells is most likely less than 1%/hr. Comparison of data on LI(fo) derived for irradiated and non-irradiated tumors indicates that clonogenic Q cells are more frequently present among cells which survived the dose of 800 rad of X-rays. These results suggest that, in R-1 tumors of about 800 mm3 the clonogenic Q cell population contains a larger fraction of hypoxic cells than the fraction of hypoxic cells present in the clonogenic P cell population. Several factors are discussed which complicate the analysis and may influence the results, e.g. re-utilization of labeled debris of dead cells from irradiated tumors.
Chemicals/CAS: DNA, Neoplasm; Thymidine, 50-89-5; Tritium, 10028-17-8
Chemicals/CAS: DNA, Neoplasm; Thymidine, 50-89-5; Tritium, 10028-17-8
Topics
radioisotopecancer cellcancer graftcell proliferationclonediagnosishistologyhypoxiain vitro studyinjuryintoxicationratrhabdomyosarcomatheoretical studyX rayAnimalCell DivisionCells, CulturedComparative StudyDNA, NeoplasmFemaleNeoplasm TransplantationRatsRats, Inbred StrainsRhabdomyosarcomaThymidineTritiumX-Rays
TNO Identifier
228357
ISSN
00088730
Source
Cell and Tissue Kinetics, 11(1), pp. 83-100.
Pages
83-100
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