A human prostatic stromal myofibroblast cell line WPMY-1: a model for stromal-epithelial interactions in prostatic neoplasia

Here we report the characterization of an SV40 large-T antigen-immortalized stromal cell line, WPMY-1, derived from the same prostate as our previousl y described epithelial cell lines. The WPMY-1 cells mere determined to be m yofibroblasts on the basis of co-expression of smooth muscle alpha-actin an d vimentin, They also show positive staining for androgen receptor, large-T antigen, and positive but heterogeneous staining for p53 and pRb, Their gr owth is stimulated by the synthetic androgen mibolerone to 145% of control (100%). Platelet-derived growth factor BE, epidermal growth factor and basi c fibroblast growth factor, at 10 ng/ml, stimulated growth to 138, 143 and 146% of control, respectively. Transforming growth factor-beta, at 10 ng/ml , inhibited serum-induced growth to 65% of control in the presence of 1% se rum, and bFGF-induced growth to 30% of control. A serum-free medium was dev eloped for optimal growth of WPMY-1 cells. They show anchorage-independent growth in soft agar, Studies on paracrine interactions show that myofibrobl ast-conditioned medium causes a marked inhibition of growth in WPE1-10 cell s, while conditioned medium from WPE1-10 prostatic epithelial cells caused only a small increase in the growth of WPMY-1 cells. WPMY-1 cells secrete v ery low levels of MMP-9 but high levels of MMP-2, markedly higher than the epithelial cells, These epithelial and myofibroblast cell lines, derived fr om the same prostate, provide novel and useful models for studies on paracr ine stromal-epithelial interactions in carcinogenesis, tumor progression, p revention and treatment of prostate cancer and benign prostatic hyperplasia .