The crosstalk between pericytes and ECs is mediated by integrin αv activity. (A,B) Quantitative RT-PCR analysis of Bcl-w (A) and VEGF-A (B) expression in MS1 endothelial cells cultured alone or together with HBVPs for 96 hours in the presence or absence of neutralizing antibodies against integrin αv. Data shown are representative of 2 independent experiments. **P < .01 vs MS1/HBVP coculture. (C) Quantification of the number of viable MS1 endothelial cells cultured alone or together with HBVPs for 96 hours with the addition of the cytotoxic drug vinblastine (50 ng/mL) in the presence or absence of neutralizing antibodies against integrin αv. **P < .01 vs vinblastine coculture. (D) Immunostaining of tissue sections from PNET of RIP1-Tag2 mice for the integrin αv ligand vitronectin (green) and the pericyte marker PDGFRβ (red). Cell nuclei (DAPI), blue. Original magnification, 400×. The panels are representative of at least 5 fields in 5 tissue sections taken from 5 mice. (E,F) Quantitative RT-PCR analysis of the expression of vitronectin in nonendothelial cells of PNET from RIP1-Tag2 mice treated or not with imatinib (E), and of B16/mock or B16/PDGFB tumors (F). *P < .05 vs B16/mock; ***P < .001 vs control. (G) Quantitative PCR analysis of expression of Bcl-w and VEGF-A in MS1 cells cultured on plastic or vitronectin. **P < .01 vs plastic.
