Heparin increases the adhesion of murine mammary adenocarcinoma cells (LM3). Correlation with the presence of heparin receptors on cell surface.

Mastocytosis is a common feature around solid tumors. Due to mast cell (MC) degranulation, heparin and other chemical mediators are released to surrounding tissues. The aim of this paper is to investigate the role of heparin and chemically modified heparins, on a murine mammary adenocarcinoma cell line adhesion properties, and the relationship with the presence of heparin binding sites in tumor cells. We show that heparin increases tumor cell adhesion in a dose-dependent manner. When the number of heparin binding sites was regulated, by culturing the cells with different FCS concentration for 24 hours, a correlation between binding capacity and heparin effect on cell adhesion was observed. The increment on cell adhesion by heparin was lower on cells with less heparin binding sites. Moreover, only heparin and a chemically modified heparin (partially N-desulfated N-acetylated), which bound to heparin-receptor, retained the ability to stimulate cell adhesion, while other modified heparins lost both effects. The increase in cell adhesion was observed on plastic dishes, albumin, as well as on fibronectin pre-coated ones suggesting that heparin effect is substratum independent. Our results show a direct relation between heparin binding to specific cell receptors and increase in cell attachment.