Characterization of transformed cell lines evolving from a normal C3H line

The development of transformed cell lines evolving from an embryo fibroblastic C3H primary culture was followed before and after the ageing crisis using different techniques. By flow cytometry, alteration of subpopulations having different DNA content and altered metabolic activity was observed after the crisis, with the trend to assume a near tetraploid DNA index at higher passages. The fibrin clot retractile activity was lost in all cases during the ageing crisis, but the outcome did not present uniform values of growth characteristics or chromosome number and tumorigenicity appeared to be a nonstable property of the transformed cell lines.