Alpha1 and beta1 integrins enhance the homing and differentiation of cultured prostate cancer stem cells.

CD133(+) prostate cancer stem cells (PCSCs) have recently been identified in human prostate cancer tissues. The present study reports the integrin profile of prostate cancer progenitor cells and the role of alpha(1) and beta(1) integrins in the homing and differentiation of PCSCs in vitro. PCSCs were isolated from the tissue specimens of patients with prostate cancer and the expression of surface integrins and adhesion patterns were determined. Our analysis of the expression of surface integrins and their adhesion patterns of prostate cancer stem cells derived from prostate cancer tissues revealed that the levels of beta(1) and alpha(2)beta(1) integrins were significantly higher (P < 0.05) than those of the other integrins. By contrast, peripheral blood-derived CD133(+) cells from prostate cancer patients showed a high level of expression (P < 0.01) of alpha(2)beta(1), alpha(v)beta(3), alpha(v)beta(5), beta(1) and alpha(1) integrins and a minimal expression of alpha(4)beta(1) integrins. Moreover, CD133(+) cells derived from both prostate cancer tissues and peripheral blood exhibited an increased degree of attachment to extracellular matrix proteins (P < 0.001) and a high expression level of alpha(2)beta(1) integrin. In vitro experiments using blocking antibodies indicated that alpha(1) and beta(1) integrins have a role in the homing and differentiation of PCSCs. This is the first report to suggest the importance of integrins in mediating the homing and differentiation of PCSCs.