High dose PGE
may promote a positive feedback loop in EGFR signal-mediated cell proliferation by inducing Cox-2 expression. A. Mucosal expression of AR in TLR4-/- mice treated with PGE 2; day 56 in AOM-DSS model (Left graph: mRNA analyzed by real-time PCR, Right graph: protein measured by ELISA). Data are represented as mean (± SD) of relative values of expression (n = 7 PBS group, n = 8 high dose and n = 6 low dose groups, *P < 0.05). B. Western blot analysis of phosphorylated EGFR and EGFR in the colon. Results from three representative samples obtained from TLR4-/- mice under each treatment in AOM-DSS model. An equal amount of protein (25 μg/lane) was loaded per lane. The membrane was sequentially probed for phospho-EGFR and EGFR.