ENDOTHELIAL-CELL DIFFERENTIATION INTO CAPILLARY-LIKE STRUCTURES IN RESPONSE TO TUMOR-CELL CONDITIONED MEDIUM - A MODIFIED CHEMOTAXIS CHAMBER ASSAY

We have developed a modified chemotaxis chamber assay in which bovine aortic endothelial (BAE) cells degrade Matrigel basement membrane and migrate and form capillary-like structures on type I collagen. This ca pillary formation occurs in the presence of conditioned media from hig hly metaslatic tumour cell lines, such as B16F10 murine melanoma or MD A-MB-231 human breast adenocarcinoma, but not in the presence of condi tioned medium (CM) from the less invasive B16F0 cell line. Replacement of tumour cell CM by 10 ng ml(-1) basic fibroblast growth factor (bFG F) also results in capillary-like structure formation by BAE cells. An anti-bFGF antibody blocks this effect, showing that bFGF is one of th e factors responsible for the angiogenic response induced by B16F10 CM in our assay. Addition of an anti-laminin antibody reduces significan tly the formation of capillary-like structures, probably by blocking t he attachment of BAE cells to laminin present in Matrigel. The anti-an giogenic compound suramin inhibits in a dose-dependent manner (complet e inhibition with 100 mu M suramin) the migration and differentiation of BAE cells on type I collagen in response to B16F10 CM. This assay r epresents a new model system to study tumour-induced angiogenesis in v itro.