Carcinogen-induced anchorage-independent growth and in vivo lethality of human MRC-5 cells.

Chemical carcinogens or u.v. irradiation induce in vitro anchorage-independent growth and in vivo lethal multicellular infiltrative growth of human MRC-5 cells. A single carcinogen treatment 8 h after release of MRC-5 cells from metabolic block induced by a deficiency of arginine and glutamine in the medium is followed within 4--5 weeks by formation of colonies of greater than 50 cells in 0.35% semi-solid agar medium. Anchorage-independent MRC-5 cells, moreover, when injected intracranially into immunologically deficient homozygous nude mice, 6--7 weeks post-carcinogen exposure, produce progressive neurological dysfunction 5--6 weeks later accompanied by lethal multifocal multicellular infiltrating lesions. The present investigation demonstrates for the first time, carcinogen-induced anchorage-independent growth and in vivo lethality of a well characterized human diploid fibroblast cell strain and indicates the potential value of MRC-5 cell transformation as a new model for the study of carcinogenesis in human cells.