Morphologic transformation of the C3H 10T1/2 cell line is accompanied by altered expression of the p53 tumor suppressor gene.
Wildtype 10T1/2 cells and 42 clonally derived morphologically transformed 10T1/2 cell lines were evaluated for expression of p53 mRNA and protein. Wildtype 10T1/2 cells expressed detectable levels of p53 mRNA and multiple immunologically distinct forms of the p53 protein, including both PAb240- and PAb246-reactive conformations of the protein. However, DNA sequence analysis revealed no mutations within the coding sequence of the expressed p53 gene(s) in wildtype 10T1/2 cells. Morphologic transformation of 10T1/2 cells resulted in clonal cell lines that overexpressed p53 mRNA and total p53 protein (PAb421-reactive) relative to the level of expression in wildtype 10T1/2 cells. Immunoprecipitation analysis demonstrated the expression of both PAb246-reactive and PAb240-reactive conformations of the p53 protein in all morphologically transformed 10T1/2 cell lines evaluated, irrespective of the tumorigenic potential of the individual line. Nonetheless, expression of PAb240-reactive p53 protein at levels equal to or higher than that found in wildtype 10T1/2 cells was associated with tumorigenicity in morphologically transformed 10T1/2 cell lines, suggesting that the relative contribution of PAb240-reactive p53 protein to the total cellular p53 protein represents an important determinant for the expression of the tumorigenic phenotype. Our results demonstrate that altered expression of p53 represents a common feature of morphologically transformed 10T1/2 cell line, suggesting that alteration of the expression of the p53 tumor suppressor gene may represent an early and necessary step in the morphologic transformation of 10T1/2 cells. Additionally, overexpression of PAb240-reactive p53 protein may influence the tumorigenic potential of morphologically transformed 10T1/2 cell lines.
Coleman
W B
WB
Department of Pathology, University of North Carolina School of Medicine, Chapel Hill 27599-7525.
Grisham
J W
JW
Smith
G J
GJ
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D017931:DNA Primers; D015870:Gene Expression; D016158:Genes, p53; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
D017931:DNA Primers; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53