INHIBITION OF CHEMOMIGRATION OF A HUMAN PROSTATIC-CARCINOMA CELL (TSU-PRL) LINE BY INHIBITION OF EPIDERMAL GROWTH-FACTOR RECEPTOR FUNCTION

Chemoattractants expressed at bony sites and pelvic lymph nodes are th ought to promote the preferential metastasis of human prostate tumor c ells to these organs. Epidermal growth factor (EGF) is a potent chemoa ttractant for several human metastatic prostate tumor cell Lines, incl uding the TSU-pr1 cell line, and EGF has been localized to the stroma of both bony sites and pelvic lymph nodes in humans. Hence, we investi gated whether the TSU-pr1 cell line expresses a functional EGF recepto r (EGFR), which when antagonized reduces EGF-mediated chemomigration o f this cell line. In this context, the EGFR immunoprecipitated from ce ll lysates of TSU-pr1 cells comigrated with the EGFR from A431 cells a t a molecular weight of 170 kD. Addition of human EGF (hEGF) to the TS U-pr1 cells for 5 min stimulated the dose-dependent biphasic phosphory lation of the EGFR, with maximal stimulation of EGFR phosphorylation o ccurring at 2 ng/ml hEGF. In addition, treatment of hEGF-stimulated (2 ng/ml) TSU-pr1 cells with 0.5 mu g/ml anti-hEGFR monoclonal antibody or 100 nM staurosporine inhibited EGFR phosphorylation. Conversely, as negative controls, treatment of hEGF-stimulated (2 ng/ml) TSU-pr1 cel ls with K252a or dimethyl sulfoxide (DMSO) vehicle did not inhibit EGF R phosphorylation. TSU-pr1 cells were stimulated to migration in 4 hr across Boyden chambers in response to 10 ng/ml hEGF. Treatment of the TSU-pr1 cells with anti-hEGFR monoclonal antibody inhibited in a dose- dependent manner the chemomigration of the TSU-pr1 cells across Boyden chambers. Similarly, treatment of the TSU-pr1 cells with staurosporin e inhibited in a dose-dependent manner the chemomigration of the TSU-p r1 cells across Boyden chambers. These results demonstrate that antago nists of hEGF-mediated hEGFR phosyhorylation also antagonize chemomigr ation of the TSU-pr1 cells across Boyden chambers, suggesting that ant agonists of the EGFR in prostate cancer may be useful in the treatment of metastatic disease. (C) 1996 Wiley-Liss, Inc.