Role of endogenous transforming growth factor beta (TGFbeta)1 in prostatic stromal cells

BACKGROUND: In this study, defined culture conditions were used to examine the effects of recombinant TGFbeta1 on prostatic stromal cells and to determine the role of endogenous TGFbeta produced by these cells. METHODS: Cells were grown +/- recombinant TGFbeta1 and cell population sizes in replicate cultures determined. In other experiments, TGFbeta1 production by prostatic stromal cells was examined and the effects of neutralization of this activity on cell population sizes and apoptosis evaluated. RESULTS: At > 1 ng/ml, TGFbeta1 reduced cell population sizes while at 0.01 ng/ml cell numbers were increased cf. controls. Stromal cells produced up to 10 ng/ml/48 hr of latent TGFbeta1 of which < 0.2% was biologically active. When cells were treated with anti-TGFbeta1 antibodies, cell numbers decreased cf. controls and the proportion of apoptotic cells increased. CONCLUSIONS: These observations suggest that TGFbeta1 is an autocrine factor made by prostatic stromal cells in which it inhibits apoptosis at the activity levels produced.