EFFECT OF TUMOR CELL-CONDITIONED MEDIUM ON ENDOTHELIAL MACROMOLECULARPERMEABILITY AND ITS CORRELATION WITH COLLAGEN

Conditioned medium prepared from mouse melanoma B16 cells (B16-CM) inc reases the macromolecular permeability of bovine aortic, venous and hu man umbilical vein endothelial monolayer. Collagen, which is synthesis ed by endothelial cells, has an important Function in regulating the p ermeability of endothelial monolayer. Briefly, low collagen content le ads to hyperpermeable structure of the endothelial monolayer. In the p resent studies, we examined the relationship between the increase of e ndothelial permeability and content of synthesised collagen of endothe lial cells cultured with B16-CM. The B16-CM reduced endothelial collag en content but did not digest collagen directly. Matrix metalloprotein ase inhibitor, 1,10-phenanthroline, inhibited the increase in permeabi lity due to addition of B16-CM. These data suggest that B16-CM acts on endothelial cells, stimulating the digestion of endothelial collagen, and that the reduced content of collagen leads to the hyperpermeabili ty of the endothelial monolayer.