title: Multistep process of neoplastic transformation of normal human fibroblasts by 60Co gamma rays and Harvey sarcoma viruses.
abstract: As reported previously (Namba et al., 1985), normal human fibroblasts were transformed by 60Co gamma-ray irradiation into immortal cells with abnormal karyotypes. These transformed cells (KMST-6), however, showed a low cloning efficiency in soft agar and no transplantability. However, upon treatment with Harvey murine sarcoma virus (Ha-MSV), the cells acquired elevated clonability in soft agar and transplantability in nude mice. Ha-MSV alone, however, did not convert normal human fibroblasts into either immortal or tumorigenic cells. The Ha-MSV-transformed KMST-6 cells showed an enhanced expression of the ras oncogene, but normal and 60Co gamma-ray-transformed cells did not. Our current data suggest that gamma rays worked against normal human cells as an initiator, giving rise to chromosome aberrations and immortality, and that Ha-MSV, probably through its ras oncogene, played a role in the progression of the malignant cell population to a more malignant one showing enhanced colony formation in soft agar and tumorigenicity in nude mice.
mesh_terms: D000818:Animals; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D003037:Cobalt Radioisotopes; D005260:Female; D005347:Fibroblasts / Q000473:pathology / Q000528:radiation effects; D005720:Gamma Rays; D006251:Harvey murine sarcoma virus; D006801:Humans; D051379:Mice; D008809:Mice, Inbred C3H; D009857:Oncogenes; D012333:RNA, Messenger / Q000032:analysis; D012513:Sarcoma, Experimental / Q000473:pathology*
chemical_list: D003037:Cobalt Radioisotopes; D012333:RNA, Messenger