Thalidomide and thalidomide transformed by pH-dependent hydrolysis or by liver enzyme treatment does Not impede the proliferation of endothelial cells.

Angiogenesis is essential for tumor growth. In the treatment of tumors with thalidomide, a rationale for its use is that it inhibits angiogenesis. To form new blood vessels, endothelial cells must proliferate. The authors were interested in describing some of the circumstances by which thalidomide may influence proliferation of endothelial cells. Human umbilical vein derived endothelial cells (HUVECs) were exposed to 4.0 or 100 microg/ml of thalidomide in dimethylsulfoxide or to 4 microg/ml of thalidomide prepared an aqueous solutions. Proliferation was determined by measuring incorporation of (3)H-thymidine. Regardless of the solvent used to dissolve thalidomide, the HUVECs treated with thalidomide were not inhibited in their ability to incorporate (3)H-thymidine.