Chloroquine's modulation of endothelial cell activity induced with basic fibroblast growth factor and human serum: Effect on mitogenesis, protease production and cell migration

Chloroquine modulates the activity of cultured human microvascular endothelial (HOME) cells in a complex fashion. At concentrations of 5-25 microM, CQ inhibits basic fibroblast growth factor (bFGF-) and human serum-induced mitogenic activity in these cells, in a dose-dependent manner. The kinetics of CQ's inhibitory actions on serum-induced mitogenesis in HOME cells slowly develops with only 30% of maximum inhibition reached after 24 hours. In HOME cells grown in serum-free medium, CQ raised tissue-plasminogen activator antigen levels in cell extracts. There was also a potentiation of bFGF-induced t-PA production. The kinetics of CQ's stimulatory effect on t-PA production by HOME cells, suggest that this effect precedes its inhibitory actions on mitogenesis. This effect of CQ on t-PA generation in endothelial cells was susceptible to cycloheximide inhibition. In wound assays, HOME cell migration, induced with bFGF and HS, was potentiated by CQ.