REGULATION OF FIBROBLAST GROWTH FACTOR-LIKE PROTEIN(S) IN THE ANDROGEN-RESPONSIVE HUMAN PROSTATE CARCINOMA CELL-LINE LNCAP

Growth of the normal and malignant prostate is known to be regulated by androgens. Part of their effect has been suggested to be mediated through coordinated regulation of secreted growth factors with autocrine function. We now examine the biological role of preferentially paracrine acting factors in growth control of prostate cancer, i.e. fibroblast growth factor(s) (FGF). Coculture experiments using the androgen-responsive prostate carcinoma cell line LNCaP as feeder cells and the FGF-dependent human adrenal carcinoma SW-13 cell line as target cells show that (i) LNCaP cells induce growth of SW-13 cells, (ii) even higher stimulation of SW-13 cells is seen in the presence of androgen treated LNCaP cells and (iii) a specific anti-bFGF antibody inhibits growth of SW-13 cells induced by androgen treated LNCaP cells; no proliferation of SW-13 cells occurs in the absence of LNCaP cells. Partial purification of the secretory products of LNCaP cells was performed by affinity chromatography using a heparin sepharose column. Fractions were tested for biological activity in a soft agar assay with SW-13 cells. Several activities could be detected, the main activity was eluted with about 1.5 M NaCl. These data suggest that androgen treatment of LNCaP cells leads to enhanced secretion of proteins which belong to the FGF-family.