EXPRESSION OF CELLULAR ADHESION MOLECULES ON HUMAN PROSTATE TUMOR-CELL LINES

By flow cytometric analysis we have examined the expression of cellular adhesion molecules (CAMs) on the surface of four different human prostate tumor cell lines: DU 145, from a brain metastasis; PC 3, from a bone metastasis; LNCaP.FGC, from a lymph node metastasis; and a primary tumor cell line, ND 1. The corresponding ligands for the expressed CAMs were, by and large, extracellular matrix proteins. We detected high-level expression of ICAM-1 on three of the four prostate cell lines, whereas LNCaP cells were negative. We observed unstable, heterogeneous expression of E-cadherin in the cell lines DU 145, PC 3, and ND 1. Flow cytometric cell sorting enabled us to divide PC 3 cells into negative and bright positive subpopulations but, after several cell divisions in culture, sorted cells returned to the original heterogeneous phenotype. The laminin-specific alpha(6) beta(4) integrin was not expressed by LNCaP, and was expressed at a low level and heterogeneously on DU 145 and PC 3 cell lines. In contrast, ND 1 cells, derived from a primary tumor, showed homogeneous and high-level expression of the alpha(6) beta(4) integrin. All of the prostate cell lines expressed the RGD-dependent binding of alpha(3) beta(1) and alpha(5) beta(1) integrins and did not reveal non-RGD-dependent alpha(4) beta(1) integrin expression. This finding provides a stimulus to investigate the inhibition capacity of RGD-containing peptides on the metastatic behavior of prostate tumor cells. (C) 1995 Wiley-Liss, Inc.