Image analysis of Feulgen-stained transformed NIH 3T3 cells differing in p21 expression and ras-induced metastatic ability.

Nuclear phenotypes of clonal and polyclonal T24 H-ras-transformed NIH 3T3 cells differing in p21 expression and experimental metastatic ability were studied in Feulgen-stained preparations by image analysis. The objective was to determine if these cells varied in their degree of chromatin condensation, as previously reported with cell transformation, or in any other chromatin texture property highlighted by image analysis parameters. The majority of nuclei in all of these ras-transformed cells exhibited increased levels of chromatin condensation, independent of ras levels or metastatic properties. This chromatin texture characteristic was assumed to be related to the transformed phenotype. No significant changes in chromatin supraorganization that could be correlated directly with ras levels or metastatic ability were found, with the exception of an increased frequency of a relatively rare phenotype in highly metastatic cells. This phenotype was characterized by an extreme contrast in packing state between condensed and noncondensed chromatin. It is suggested that ras transformation results in alterations in chromatin structure but that there is not a simple relationship between ras p21 expression levels or ras-induced metastatic ability and the degree of these changes.