EFFECT OF EPIDERMAL GROWTH-FACTOR ON PROSTATE-CANCER CELL-LINE PC3 GROWTH AND INVASION

Elevated levels of epidermal growth factor (EGF) and epidermal growth factor receptor (EGF-R) have been demonstrated in prostate cancer cell lines and clinical specimens suggesting a role for polypeptide growth factors in prostate tumor cell growth and invasion. To more clearly d efine the role of EGF in prostate cancer invasion, we undertook a seri es of studies utilizing the PC3 prostate cancer cell line, an aggressi ve, hormone-independent cell line derived from a metastatic lesion. No statistical differences were noted in the growth of PC3 cells under s erum-free conditions when EGF (10(-10) M-10(-8) M) or monoclonal anti- EGF-R antibody (10(-11) M-10(-8) M) were added. Utilizing the Boyden c hamber microinvasion assay, EGF supplemented cells demonstrated a stat istically significant augmentation in invasion (P < 0.05) when compare d to control cells at each time point in the study. With increasing le ngth of exposure to EGF, the number of concentrations that produced si gnificant invasion increased: day 1 (10(-8) M), day 3 (10(-8), 10(-9) M), and day 5 (10(-7), 10(-8), 10(-10) M). Northern blot analysis of E GF supplemented cells revealed an increase in expression of urokinase plasminogen activator (uPA) RNA, a serine protease involved in the reg ulation of pericellular proteolysis and membrane degradation. Protein analysis confirmed these findings. Statistically significant inhibitio n of invasion by anti-uPA antibodies was demonstrated for EGF-stimulat ed and PC3 control cells. Our results demonstrate that certain concent rations of EGF augment invasion in the PC3 cell line. This enhancement of invasion occurs in part by an overproduction of uPA, an extracellu lar protease. These findings suggest that the autocrine production of EGF may potentiate tumor cell invasion. (C) 1994 Wiley-Liss, Inc.