Parathyroid hormone-related protein overexpression in the human colon cancer cell line HT-29 enhances adhesion of the cells to collagen type I

The present experiments examined the potential ability of parathyroid hormo ne-related protein (PTHrP) to influence growth of the human colon cancer ce ll HT-29 and the ability of the cell to adhere to several extracellular mat rix (ECM) proteins found in normal tissues. Addition of PTHrP analogs, PTHr P (1-34), PTHrP (67-86), or PTHrP (107-139), to HT-29 cells in culture did not influence cell growth or the adhesion of the cells to wells coated with fibronectin, laminin, or collagen type I. Likewise. in HT-29 cells induced to overexpress PTHrP by stable transfection with PTHrP cDNA, compared to v ector-transfected control HT-29 cells, no effect on cell growth occurred. H owever, in the transfected cells, the increased production of PTHrP signifi cantly enhanced cell adhesion to type I collagen but not to fibronectin or laminin. The results raise the possibility that PTHrP might play a role in colon tumor invasion and metastasis by influencing cell adhesion to specifi c extracellular matrix proteins. (C) 2001 Elsevier Science B.V. All rights reserved.