BENIGN PROSTATIC STROMAL CELLS ARE REGULATED BY BASIC FIBROBLAST GROWTH-FACTOR AND TRANSFORMING GROWTH-FACTOR-BETA-1

The current study was undertaken, using cultures of prostatic epitheli al and stromal cells, to determine the functional interactions between androgens, basic fibroblast growth factor (FGF2) and transforming gro wth factor-beta 1 (TGF beta 1) and their importance in maintaining str omal homeostasis. Treatment of stromal cells with TGF beta 1 significa ntly increased intracellular FGF2 and FGF2 sequestered to the extracel lular matrix. FGF2 was also detected in stromal conditioned medium (SC M), but at levels 70-fold less than found in cell lysates. TGF beta 1 (0.1 ng/ml) treatment caused an initial increase of 86% in secreted FG F2 levels, but high concentrations of TGF beta 1 (5 ng/ml) decreased F GF2 levels by 38%, relative to the untreated control. Further studies showed that epithelial conditioned medium (ECM), androgen-treated, str omal conditioned medium (ASCM), but not SCM were mitogenic for stromal cells. Both ECM and ASCM caused a threefold increase in DNA synthesis . FGF2 may be the mediator of these interactions, since the mitogenic effect of both ECM and ASCM was significantly reduced by the addition of anti-FGF2 neutralising antibody. We hypothesise that the lack of re sponse of stromal cells to SCM is due to TGF beta 1 blocking the mitog enic effect of FGF2. Thus down-regulation of TGF beta 1 synthesis, by androgens, results in stromal proliferation by ASCM.