EXPRESSION OF CD44 IN PROSTATE-CANCER CELLS - ASSOCIATION WITH CELL-PROLIFERATION AND INVASIVE POTENTIAL

High level expression of the cell surface adhesion molecule CD44 stand ard from and its splice variants, have been causally linked to tumor. metastasis. In this study, we investigated the significance of CD44 ex pression in human prostatic carcinoma cells. Immunocytochemistry showe d high level expression of CD44 in cells from a high grade prostate tu mor, and two androgen-independent, invasive prostatic carcinoma lines, PC-3 and TSU-Pr1. Normal prostatic epithelial cells and LNCaP, a low metastatic, androgen sensitive cell line, expressed none to a very low level of CD44, although mRNA transcripts were detected in all cell li nes. Immunoprecipitation detected two proteins of Mr approximate to 14 0 kDa and 210 kDa in PC-3, and predominantly the Mr similar to 95 kDa protein in TSU Pr1, but none in LNCaP. Most importantly, a neutralizin g antibody to CD44 inhibited cell proliferation and basement membrane invasive activity, suggesting a definitive role of CD44 in prostate tu mor growth and metastasis.