P53 IS INVOLVED IN THE INHIBITION OF CELL-PROLIFERATION MEDIATED BY ACTIVIN-A IN CULTURED HUMAN PROSTATE-CANCER LNCAP CELLS

Activin A in a concentration ranging from 0.7 to 75 ng/ml specifically inhibited cell growth of an androgen-sensitive human prostate cancer line, LNCaP, but had no effects on two androgen-insensitive human pros tate cancer lines, PC3 and DU-145. This activin-mediated inhibition of cell growth in LNCaP cells results from a decrease of cell proliferat ion and an increase of apoptosis. Northern blot analysis of mRNA expre ssion encoding human p53 in untreated and activin-treated LNCaP cells resulted in upregulation of p53 gene expression. We conclude that auto crine inhibition of cell growth in LNCaP cells by activin is in part r elated to the expression of the p53 gene.