Figure 1

ET-1 induces COX-2 expression via c-Src tyrosine kinase in bEnd.3 cells. (A,B) Involvement of protein tyrosine kinases in ET-1-induced COX-2 expression; cells were pretreated with various concentrations of genistein (0.1, 1, or 10 nM) for 1 h and incubated with 10 nM ET-1 for 6 h (A) or 1 h (B). (C,D) Involvement of c-Src tyrosine kinase in ET-1-induced COX-2 expression; cells were pretreated with various concentrations of PP1 (1, 10, or 100 nM) for 1 h and incubated with 10 nM ET-1 for 6 h (C) or 1 h (D). (E) Time dependence of ET-1-induced c-Src phosphorylation; cells were treated with 10 nM ET-1 for the indicated time intervals in the presence or absence of PP1 (100 nM). The phosphorylation of c-Src was analyzed by Western blot using an anti-phospho-c-Src antibody. (F) Cells were transfected with shRNA of c-Src (sh-Src) for 24 h (Topo: as a control) and treated with 10 nM ET-1 for 6 h. The COX-2 protein (A,C,F) and mRNA (B,D) were analyzed by Western blotting and RT-PCR, respectively. Data are expressed as mean ± SEM of three individual experiments (n = 3). ^* P < 0.05, ^# P < 0.01 as compared with cells stimulated by ET-1 alone.