Transformation of human cells in culture by N-methyl-N′-nitro-N-nitrosoguanidine

Abstract

THE development of in vitro cell culture systems in which healthy cells can be transformed (converted to malignant cells) by chemicals, and detailed studies of the interaction of chemical carcinogens (or their activated forms) and cells, have aided the study of chemical carcinogenesis. In vitro chemical transformation of various rodent cells has been well established^1–3. Many attempts have been made to transform various cultured normal or genetically abnormal human cells with chemical carcinogens without success^4,5. We have tried to transform human cells from both normal and abnormal individuals and as has been the experience of others, have failed to observe any changes in such cultures. Therefore, the possibility of using continuous lines of human sarcoma cells for chemical transformation was investigated, since certain human sarcoma cell lines are susceptible to transformation by both DNA and RNA tumour viruses^6–8. This communication reports results of experiments showing that human osteosarcoma clonal cells can be transformed in vitro by N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), a known potent carcinogen^9,10 and that these transformed cells produced tumours when injected into NIH nude athymic mice.