Efficacy of low-molecular-weight heparin and unfractionated heparin to prevent adhesion of human prostate and bladder carcinoma and melanoma cells to bovine endothelial monolayers. An in vitro study and review of the literature.

Adherence of human prostate carcinoma (PC 3, DU 145), bladder (647 V, J 82) carcinoma and melanoma (RPMI-8252) cell lines to plastic and bovine endothelial monolayers (BEM) was tested in the presence of 0.5, 1, 5, 10, 20 IU of low-molecular-weight heparin (LMWH), unfractionated heparin (UFH) or saline as a control. Culture medium was supplemented either with 5% fetal calf serum or with human plasma. Floating tumor cells were counted after 2, 4, 24 h of culture in microtiter plates without BEM and after 1.5, 3 and 24 h of culture on BEM. Twenty IU of LMWH increased the numbers of bladder carcinoma cells adhering to BEM as did 20 IU of UFH in cultures of DU 145 prostate carcinoma and RPMI-8252 melanoma cells. LMWH obviously does not prevent human prostate and bladder carcinoma and melanoma cells from adhering to BEM more effectively than UFH. The in vivo effect of UFH and perhaps also LMWH that hinders intravenous tumor cell colonization in blood vessels obviously does not depend on the interaction with endothelial cells alone.