COMPARATIVE-STUDIES OF THE MITOGENIC EFFECTS OF EPIDERMAL GROWTH-FACTOR AND TRANSFORMING GROWTH-FACTOR-ALPHA AND THE EXPRESSION OF VARIOUS GROWTH-FACTORS IN NEOPLASTIC AND NONNEOPLASTIC PROSTATIC CELL-LINES

BACKGROUND. The role of growth factors in prostate cell growth has bee n investigated as these peptides may be involved in the autonomous gro wth of hormone-independent prostate cancer. METHODS. Responses of neop lastic (PC-3 and CPA) and non-neoplastic (CAFE) prostatic cell lines t o epidermal growth factor (EGF) and transforming growth factor-alpha ( TGF-alpha) were determined using clonogenic and growth curve analysis. The constitutive expression of EGF, TGF-alpha, and TGF-beta 1-3 mRNA was examined using Northern blotting and EGF and TGF-alpha protein lev els were determined immunohistochemically. RESULTS. Growth curve and c lonogenic analysis indicated that EGF and TGF-alpha were mitogenic in each cell line. The magnitude of the clonogenic response varied betwee n the cell lines, with CPA cells showing the greatest growth increases . CPA cells also displayed the highest levels of EGF and TGF-alpha mRN A and protein. TGF-beta 1 mRNA was detected in the order of magnitude, PC-3 > CPA > CAFE. Furthermore, PC-3 and CPA cells expressed TGF-beta 3 and TGF-beta 2 transcripts respectively. In each cell line, the exp ression of any growth factor mRNA was not affected by exogenous EGF. C ONCLUSIONS. The growth responses of the cell lines to EGF and TGF-alph a did not correlate with their constitutive levels of EGF and TGF-alph a mRNA and protein, thus whilst growth factors may be important in mal ignant cell growth, other pathways may also be involved in the autocri ne regulation of cell proliferation. (C) 1997 Wiley-Liss, Inc.