Cytotoxicity resistance, proliferation and tubulogenesis of Sunitinib and Sorafenib treated PTEC and HUVEC. (A): Relative vitality of HUVEC treated with different concentrations (x-axis, logarithmic scale) of Sunitinib and Sorafenib, showing the IC50 (1.4675 μM for Sunitinib and 1.5329 μM for Sorafenib, dotted line). (B and C): Cell survival and proliferation of PTEC (black columns) and HUVEC (white columns) after 48 h incubation with 1 μM and 2.5 μM Sunitinib or Sorafenib. Cytotoxicity was detected as MTT assay, proliferation as BrdU assay. (D): Capillary-like organization of PTEC (black columns) and HUVEC (white columns). Cells were seeded on Matrigel and observed at different times points. Images at 18 hours of treatment were analyzed and total tubule length was measured for each field. Data are the mean ± S.E.M. of a minimum of three independent experiments performed with three (PTEC1, 2 and 3) or five (HUVEC) different cell lines in triplicate. Statistical significance *p < 0.05.