BAPTA (30 μM), BTP-2 (20 μM), and CAI (10 μM) block the proliferation of both RCC-EPCs (A) and N-EPCs (B). The effect of BTP-2 on N-EPCs has already been shown in [27]. Results are expressed as percentage of growth compared with control (given as 100% growth). C, statistical evaluation of the block exerted by BAPTA (30 μM), BTP-2 (20 μM), and CAI (10 μM) on the assembly into tubulary-like structures of RCC-EPCs. D, digital images of endothelial tubes obtained by bright-field light microscopy 10 hours after plating the cells in Matrigel under control conditions (upper Panel), and in the presence of BAPTA (30 µM), BTP-2 (20 µM), and CAI (10 µM). Cultures were observed up to 24 ours but their appearance did not substantially change after pictures were taken. The bar length is 250 µM.