Transforming growth factor-beta is an autocrine mitogen for a novel androgen-responsive murine prostatic smooth muscle cell line, PSMC1

A prostatic smooth muscle cell line (PSMC1) was established from the dorsol ateral prostate of p53 null mice. The cell line is nontumorigenic when inoc ulated subcutaneously, under the renal capsule or intraprostatically in syn geneic mice. These cells express alpha -smooth muscle actin (alpha -SMA), i ndicating their smooth muscle origin, and TGF-beta significantly enhances e xpression of alpha -SMA. The cells express both androgen receptor (AR) mRNA and protein, and respond mitogenically to physiological concentrations of androgens. PSMC1 cells produce significant amounts of TGF-beta, which stimu lates growth by an autocrine mechanism. Dihydrotestosterone (DHT) increases proliferation of PSMC1 cells by promoting TGF-beta secretion. Considering the significant inhibitory effect of TGF-beta on prostatic epithelial cells and its stimulatory effect on the PSMC1 cells, we postulate that TGF-beta produced by prostatic smooth muscle cells may have a paracrine effect on th e prostatic epithelium. We also postulate that TGF-beta may be involved in the etiology of benign prostatic hyperplasia (BPH) by stimulating excessive stromal proliferation. Line PSMC1 is the first reported androgen-responsiv e murine smooth muscle cell line. It will be useful for in vivo and in vitr o experiments to study the mechanisms of androgen action on prostatic strom a and for delineating the interactions that occur between prostatic smooth muscle and epithelium that may lead to prostatic diseases such as BPH. J. C ell. Physiol. 185:416-424, 2000. (C) 2000 Wiley-Liss, Inc.