ErbB-4 may control behavior of prostate cancer cells and serve as a target for molecular therapy

PURPOSE. To assess ErbB-4 expression in advanced human prostate cancer (PC) cell lines, the role of ErbB-4 in motility, migration, and proliferative/tumorigenic potential of PC: cells, and efficacy of anfi-ErbB-4 monoclonal antibody (Mab) treatment on PC cells in vitro and tumor growth in vivo. MATERIALS AND METHODS. Established advanced human PC cell lines (PC-3, CIA, and Du-145) were evaluated for ErbB-4 expression Several Cl-1 cell line clones expressing various levels of ErbB-4 were isolated, their motility, migration capacity, and in vitro proliferation as well as survival following Mab treatment were evaluated. Tumorigenicity and proliferation capacity of these clones in vivo and efficacy of Mab treatment on tumor growth were estimated by measurements of subcutaneous tumors developed in nude mice. RESULTS. PC cell lines studied express ErbB-4. Both PC-3 and Du-145 cell lines express high ErbB-4 levels; only 50% of Cl-1 cells express ErbB-4 with large heterogeneity. Cl-1 sub-clones highly expressing ErbB-4 showed increased cell motility, migration, and proliferation rate in vitro and enhanced growth in vivo, compared to clones with low ErbB-4 expression. Mab treatment inhibited the growth of cells expressing high but not low ErbB-4 levels in vitro and decreased the growth of subcutaneous tumors in nude mice generated by ErbB-4 highly expressing cells. CONCLUSIONS. High expression of ErbB-4 in prostate cancer Cl-1 cell clones correlated with high proliferative and migration capacity and high tumorigenic potential. The inhibitory effect of Mab on cell proliferation and on subcutaneous tumor growth suggests ErbB-4's potential as a target for molecular anti cancer therapy.