Clonogenicity of mammalian cells in hybrid spheroids: a new assay method.
A new in vitro method for determining the clonogenicity of mammalian cells in culture is described. The method is based on packaging clonogens into agglomerates of non-proliferating, but metabolically active, HeLa cells. These agglomerates, termed hybrid spheroids, provide an in vivo-like environment for entrapped test cells, offering a realistic system for prospective tumor control studies. Clonogenicity is determined by varying the number of test cells per hybrid spheroid so that some, but not all, spheroids give rise to macrocolonies. From the fraction of non-colony forming spheroids, the average number of clonogens per spheroid can be calculated, and the survival of irradiated test cells determined. In this fashion survival curves were obtained for HeLa, B-16 and HEp3 cells which corresponded to survival curves obtained in the conventional manner. The clonogenicity of cells, derived from a human maxillary melanoma surgical specimen was also determined by the hybrid spheroid method. With this method, plating efficiency increased in those cells which normally plate poorly, such as tumor cells, thus enabling survival measurements when this is not practical using conventional methods.
Djordjevic
B
B
Department of Radiation Oncology, SUNY Health Sciences Center, Brooklyn 11203.
Lange
C S
CS
D000818:Animals; D002452:Cell Count; D002999:Clone Cells / Q000473:pathology*; D004307:Dose-Response Relationship, Radiation; D006367:HeLa Cells; D006651:Histocytochemistry; D006801:Humans; D006822:Hybrid Cells / Q000473:pathology / Q000528:radiation effects; D051379:Mice; D009940:Organoids; D014407:Tumor Cells, Cultured / Q000473:pathology*; D014410:Tumor Stem Cell Assay