Relation between colony formation in calciumdashdeficient medium, colony formation in soft agar, and tumor formation by T51B rat liver cells

Abstract

T51B rat liver cells and several carcinogen-treated, carcinogen + saccharintreated, or spontaneously altered clones of T51B cells were tested for their abilities to form colonies in calciumdashdeficient medium and soft agar and to produce tumors in athymic nude mice. Most (10 out of 11) of the clones which were derived from colonies in calciumdashdeficient medium were unable to form colonies in soft agar and 8 out of 11 were non-tumorigenic. Conversely, 6 out of 9 clones derived from colonies in soft agar were unable to multiply significantly in calciumdashdeficient medium and 5 of these 6 clones were also non-tumorigenic. Two of these 9 soft agar-growing clones were tumorigenic, one of which also proliferated in calciumdashdeficient medium, and the other of which acquired the ability to proliferate in calciumdashdeficient medium after it became able to form tumors in athymic nude mice. Thus, T51B rat liver cells gain the ability to grow in calciumdashdeficient medium and soft agar independently during the process of neoplastic transformation and neither characteristic by itself reliably predicts tumorigenicity.