title: Glutaraldehyde-fixed transformed and non-transformed cells induce contact-dependent inhibition of growth in non-transformed C3H/10T1/2 mouse fibroblasts, but not in 3-methylcholanthrene-transformed cells.
abstract: C3H/10T1/2 mouse fibroblasts showed a pronounced inhibition of growth when reaching a critical cell density. The situation of high cell density could be mimicked by the addition of glutaraldehyde-fixed cells to sparsely seeded proliferating cells. Treatment of the C3H/10T1/2 cells with 3-methylcholanthrene led to a high frequency of piled up foci (118 type II and type III foci in 78 cultures). Cells of a type III focus of a treated culture were cloned. These cells grew in soft-agar and reached 10 times higher cell densities when grown in culture dishes, than did their non-transformed counterparts. Glutaraldehyde-fixed transformed cells did not differ from fixed non-transformed cells in the ability to inhibit the growth of sparsely seeded non-transformed cells. On the other hand, both the addition of fixed normal or transformed C3H/10T1/2 cells did not affect the growth rate of transformed cells. In a concept explaining the density-dependent inhibition of growth of non-transformed cells by a specific interaction of plasma membrane-localized effectors with plasma membrane-localized receptors, the present findings would indicate that the transformed cells used express active effectors but are functionally defective in the receptors or in the signal transmission.
mesh_terms: D000818:Animals; D002450:Cell Communication; D002455:Cell Division; D002462:Cell Membrane / Q000648:ultrastructure; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D005976:Glutaral; D007700:Kinetics; D008748:Methylcholanthrene / Q000633:toxicity*; D051379:Mice
chemical_list: D008748:Methylcholanthrene; D005976:Glutaral