COX inhibitors reduce β-catenin activity in AE-expressing BM cells. (A) Western blot analysis demonstrates that COX inhibitors NS-398, nimesulide, and INDM decreased β-catenin protein levels in AE-expressing mouse BM cells. WT and AE/Mx1-Cre mouse lin⁻ BM cells were cultured with the vehicle (DMSO) or COX inhibitors (50 μM) for 4 weeks. (B) Protein band intensity in (A) was normalized with β-actin. Relative protein level of β-catenin was calculated as fold change compared with WT BM cells in DMSO. In AE/Mx1-Cre BM cells, NS-398, nimesulide, and INDM reduced β-catenin levels to 0.24 ± 0.09-fold, 0.18 ± 0.06-fold and 0.28 ± 0.15-fold of the vehicle control (DMSO), respectively. COX inhibitors also suppressed β-catenin protein expression in AE/Mx1-Cre BM cells after 1 week of treatment (supplemental Figure 4). (C) The expression of β-catenin target genes was measured by real-time RT-PCR and normalized to β-ACTIN expression. Relative expression was calculated as fold change relative to WT vehicle-treated cells (WT DMSO). Data represent mean ± SD; Student t test. *P < .05; **P < .01; ***P < .001 when compared with AE DMSO.