STEROID-GROWTH FACTOR INTERACTION IN HUMAN PROSTATE-CANCER .1. SHORT-TERM EFFECTS OF TRANSFORMING GROWTH-FACTORS ON GROWTH OF HUMAN PROSTATE-CANCER CELLS

In order to better define potential mechamisms of growth regulation in human prostate cancer cells, we have compared biological response (su ch as short-term response to both transforming growth factor alpha and beta; TFG alpha and TFG beta) in relation to hormone sensitivity of L NCaP, DU145, and PC3 cells. Androgen receptor (AR) and epidermal growt h factor receptor (EGF-R) content of each cell line was also investiga ted In addition, expression of EGF, TGF alpha and TGF beta was evaluat ed through immunofluorescent staining. Growth of androgen non-responsi ve PC3 cells was stimulated by TGF alpha (about 35%) and inhibited by TGF beta (more than 50%), with respect to controls, after 48 h exposur e. Conversely. AR-positive, hormone-responsive LNCaP cells proved to b e poorly sensitive, at least short-term, to either growth factor. Furt hermore, high levels of both EGF-R and TGF alpha, and a fairly high am ount of EGF, were found in DU145 cells and, to a lesser extent, in LNC aP cells; in contrast, PC3 cells exhibited low expression levels of bo th receptors (EGF-R) and ligands (EGF, TGF alpha), but displayed remar kable TGF beta binding and relatively high levels of endogenous TGF be ta. Overall, these results suggest a differential sensitivity to TGF a lpha and TGF beta by prostate cancer cells; TGF alpha response seems n ot to be proportional to the EGF-R content of individual cell lines.