CXCL8/IL8 induces the up-regulation of VEGF in endothelial cells through
CXCR2. A, serum-starved SVEC cells were treated for the indicated
times with 100 ng/ml CXCL8/IL8 or exposed to 1% O2. Vegfa
mRNA levels were determined by quantitative PCR, and cellular (B) and
secreted (C) VEGF levels were determined in lysates and culture
media, respectively. pVEGFR2, phosphorylated VEGFR2. D,
serum-starved SVEC cells were pretreated (30 min) with vehicle
(Control) or 50 nm SB-225002
(CXCR2inh), stimulated for 12 h with phosphate-buffered
saline (Control) or 100 ng/ml CXCL8/IL8, and analyzed by Western blot
(WB). E, SVEC cells were infected with lentiviruses encoding
for GFP and murine CXCR2 shRNA or control shRNA. Cells were selected by
fluorescence-activated cell sorter. Two groups showed diminished CXCR2 levels
(shRNA1 and shRNA3) by Western blot analysis, whereas
another displayed inefficient knockdown (shRNA2) and served as an
additional control. F, analysis of VEGF up-regulation in response to
12 h of treatment with 100 ng/ml CXCL8/IL8 in SVECs with different CXCR2
expression. ANOVA test, *, p < 0.01, **, p <
0.001.