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

Abstract

Here we report the characterization of an SV40 large-T antigen-immortalized stromal cell line, WPMY-1, derived from the same prostate as our previously described epithelial cell lines. The WPMY-1 cells were determined to be myofibroblasts on the basis of co-expression of smooth muscle alpha-actin and vimentin. They also show positive staining for androgen receptor, large-T antigen, and positive but heterogeneous staining for p53 and pRb. Their growth is stimulated by the synthetic androgen mibolerone to 145% of control (100%). Platelet-derived growth factor BB, epidermal growth factor and basic 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% serum, and bFGF-induced growth to 30% of control. A serum-free medium was developed for optimal growth of WPMY-1 cells. They show anchorage-independent growth in soft agar. Studies on paracrine interactions show that myofibroblast-conditioned medium causes a marked inhibition of growth in WPE1-10 cells, 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 very low levels of MMP-9 but high levels of MMP-2, markedly higher than the epithelial cells. These epithelial and myofibroblast cell lines, derived from the same prostate, provide novel and useful models for studies on paracrine stromal-epithelial interactions in carcinogenesis, tumor progression, prevention and treatment of prostate cancer and benign prostatic hyperplasia.

Tumour-derived TGF-β1 modulates myofibroblast differentiation and promotes HGF/SF-dependent invasion of squamous carcinoma cells

“…This has been demonstrated previously in breast cancer where TGF-b1 produced by breast cancer cells activates normal breast stromal fibroblasts and promotes them to produce proteases (Ronnov-Jessen and Petersen, 1993;Sieuwerts et al, 1998). Similar interactions have been shown in prostatic carcinomas (Olumi et al, 1999;Webber et al, 1999), and in the fibrosis observed in organs such as the kidney (Lewis and Norman, 1998) and liver (Kinnman and Housset, 2002).…”

“…Indeed, high levels of the cytokine are usually associated with MF-containing lesions (Tuan and Nichter, 1998). In many types of cancers, TGF-b1 is overexpressed by carcinoma cells (Ronnov-Jessen et al, 1996;Rowley, 1998), and it has been proposed previously that the expression of this cytokine by breast and prostate carcinoma cells induces reactive stroma (Ronnov-Jessen et al, 1996;Rowley, 1998;Webber et al, 1999). TGF-b1 has many effects: In addition to inhibiting epithelial cell proliferation, it also promotes the secretion of matrix proteins and proteases.…”

Differential androgen receptor signals in different cells explain why androgen-deprivation therapy of prostate cancer fails

“…Consistent with the above findings, mice injected with PC-3-v cells developed bigger prostate primary tumors that were less differentiated (Niu et al, 2008b) and larger PLN metastatic tumors (Niu et al, 2008a) than mice inoculated with PC-3-AR9 cells. Moreover, when PC-3-v or PC-3-AR9 cells were co-cultured with WMPY1 stromal cells (Webber et al, 1999) and orthotopically transplanted in nude mice, PC-3-AR9 co-cultured cells still produced smaller primary and metastatic tumors than PC-3-v co-cultured cells, suggesting that even in the presence of stromal AR stimulation, the suppressor function of the epithelial AR remains effective. Using transfectants of PC-3 cells with an inducible AR-expressing transgene, Nelius et al (2007) also observed that induction of AR expression in an inducible PC-3-AR þ line resulted in an androgendependent decrease in invasion in vitro and decreased tumorigenecity because of decreased microvascular density that led to increased tumor cell apoptosis after subcutaneous inoculation in nude mice.…”

The diverse and contrasting effects of using human prostate cancer cell lines to study androgen receptor roles in prostate cancer

“…The immortalized human prostate stromal cells WPMY-1 express functional AR and secrete paracrine grow th factors [70]. To examine the stromal AR roles and to maintain intact stromal microenvironments, we applied WPMY-1 cells and their AR knockdown clone (WPMY-1 AR siRNA) to the lower chambers of Matrigel-coated transwells and seeded the PC3-v or PC3-AR9 epithelial cells in the upper chambers [38].…”