PGE₂ regulation of Flt3 expression enhances DC progenitor cell survival through STAT3-mediated elevation of survivin. (A) Representative FACS plot of pre-cDC phospho-STAT3 expression generated from CDPs cultured in Flt3L with or without indomethacin and relative phospho-STAT3 expression in pre-CDC (mean ± SEM; n = 3 mice pooled per experiment; 3 experiments). (B) Total DC generation from Lin^neg BM cells (2 × 10⁵ cells/well) cultured for 9 days with Flt3L with or without indomethacin and/or stattic (mean ± SEM; 2 experiments; n = 3 mice/group/experiment; *P < .05 compared with vehicle; #P > .05 compared with indomethacin). (C) Survivin expression in pre-cDCs generated in vitro from Flt3L-cultured CDPs with or without indomethacin (mean ± SEM; n = 3 mice pooled per experiment; 3 experiments). (D) Total DC generation from Lin^neg BM cells nontransduced (NT) or transduced with survivin overexpression or control vector (mean ± SEM; n = 3 mice/group/experiment; 2 experiments; *P < .05 compared with vehicle, †P < .05 compared with vector control). (E) Total DC generation from Lin^neg BM cells (2 × 10⁵ cells/well) cultured for 9 days with or without Flt3L and/or indomethacin. (F) Mean fluorescence intensity (MFI) of Flt3 receptor on CDPs and pre-cDCs (mean ± SEM; n = 4 mice). (G) Lin^neg BM cells transduced with Flt3 MSCV-IRES-EGFP or control vector and cultured with or without indomethacin. (Left) DC generation after 9 days of culture (mean ± SEM; N = 6 mice assayed individually; 2 experiments); (middle) MFI of phospho-STAT3 expression; (right) survivin expression in pre-cDCs after 5 days of culture (mean ± SEM; N = 3 mice). *P < .05. V indicates vehicle; and Indo, indomethacin.