Cultured human prostate-derived fibroblasts produce a factor that stimulates their growth with properties indistinguishable from basic fibroblast growth factor.

Fibrostromal proliferation is believed to be important in the development of benign prostatic hyperplasia (BPH). We found that a mitogen for cultured mesodermal-derived cells was present in extracts of BPH tissue. The mitogen was identified as basic fibroblast growth factor (bFGF). Previous studies did not determine the cell population(s) responsible for bFGF production in the prostate. This information is important to the understanding of the role of bFGF in the etiology of BPH. Human prostate-derived fibroblasts (PF) were initiated in culture. Recombinant bFGF and PF lysates stimulated tritiated thymidine uptake by quiescent PF cells. Greater than 90% of the mitogen in PF lysates bound to heparin-Sepharose and had the same elution profile and apparent molecular weight as bFGF isolated from BPH tissue. The growth factor in PF lysates competed with recombinant iodinated bFGF for binding to antiserum to (1-24)bFGF. Cultured PF incorporated 35S-methionine into protein that was precipitated by antiserum to bFGF. The apparent molecular weight of the radiolabeled protein, about 17,000, was similar to authentic bFGF. The observations are consistent with the interpretation that cultured PF synthesize a growth factor that stimulates their growth with properties that are indistinguishable from bFGF.