Figure 3. EGFR mediates the induction of IL-8 by Ox-PAPC in HAECs.

(A) Ox-PAPC increased IL-8 expression in HAECs in a time-dependent manner as determined by qRT-PCR. (B) Ox-PAPC activates EGFR. Cells were treated with Ox-PAPC (50ug/ml) for 0 to 30 min and the phosphorylation of Tyr¹⁰⁶⁸ of EGFR was determined by Western blot using pY¹⁰⁶⁸ -EGFR antibody. (C) EGFR silencing by siRNA transfection significantly reduced IL-8 induction by Ox-PAPC (50ug/ml, 4hrs). The mRNA content of IL-8 was determined by qRT-PCR. Multiple siRNAs for EGFR with different nucleotide sequences showed similar effects. The silencing of target proteins was confirmed by qRT-PCR and Western blotting as shown in Suppl. Figure II. (D) EGFR inhibitor reduced IL- expression by Ox-PAPC. Cells were pretreated with EGFR inhibitor AG1498 (10uM) for 1hr, and cotreated with Ox-PAPC (50ug/ml) for 4hrs. Vehicle (DMSO) was used as control treatment. The IL-8 mRNA levels were determined by qRT-PCR. Western blotting and qRT-PCR were repeated at least three times with reproducibility and representative results were shown. The values were represented as mean+SD, ** p<0.01, N=3 for reaction.