Differentiation of simian virus 40 transformed human mammary epithelial stem cell lines to myoepithelial-like cells is associated with increased expression of viral large T antigen.
Cloned simian virus 40 (SV40)-transformed human breast epithelial cell lines can differentiate to myoepithelial-like cells, and these can be isolated as clonal cell lines. Immunofluorescent and immunocytochemical analysis of such cell lines growing on plastic surfaces, collagen gels, and as tumor-nodules in nude mice indicate that all the cell lines produce SV40 large T antigen, but that the production of this antigen is qualitatively increased in the myoepithelial-like cells and cell lines. The myoepithelial-like cell lines produce 4-6 times more immunoprecipitable large T antigen than the parental epithelial cells. The amount of mRNA for large T antigen is also increased by 3.5-5-fold in the myoepithelial-like cell lines when analysed by dot-blot or by Northern hybridisations. Thus, differentiation along the myoepithelial-like cell pathway is associated in these SV40-transformed cells with increased expression of the viral large T antigen. It is suggested that immortalization of primary breast epithelial cell cultures may be, in part, due to the expression of large T antigen preventing processes of terminal keratinization.
Rudland
P S
PS
Biochemistry Department, University of Liverpool, England.
Barraclough
R
R
D000952:Antigens, Polyomavirus Transforming / Q000235:genetics*; D001940:Breast / Q000166:cytology*; D002454:Cell Differentiation; D002472:Cell Transformation, Viral; D004847:Epithelial Cells; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D006801:Humans; D011233:Precipitin Tests; D012333:RNA, Messenger; D012367:RNA, Viral; D013539:Simian virus 40
D000952:Antigens, Polyomavirus Transforming; D012333:RNA, Messenger; D012367:RNA, Viral