COX inhibitors reduce the extended self-renewal capacity of AE-expressing mouse BM cells through a PGE2-dependent pathway. (A) BM cells isolated from WT mice were cultured in MethoCult M3434. Colonies were scored and the cells were serially replated at 7-day intervals. The presence of COX-2 inhibitor NS-398 (50 μM) or nimesulide (50 μM), COX-1 inhibitor SC-560 (50 μM), and a nonselective COX inhibitor indomethacin (INDM, 50 μM) did not affect colony formation of these cells (ANOVA test; P > .05). (B) BM cells isolated from AE/Mx1-Cre mice were cultured, treated, and scored under the same condition as WT mouse BM cells. COX inhibitors reduced the colony forming units of AE-expressing BM cells. (C) COX inhibitors or PGE2 receptor EP2/EP3 dual antagonist AH6809 (30 μM) showed similar inhibitory effects on the colony forming units of AE-GFP-expressing BM cells. (D) EP2/EP3 dual antagonist AH6809 did not affect colony formation of WT mouse BM cells. (E) Treatment of PGE2 partially abrogates the inhibitory effects of INDM on the colony formation of AE/Mx1-Cre BM cells. These results are representatives of at least 2 independent experiments. Data were shown as mean ± SD; Student t test.*P < .05; **P < .01; ***P < .001.