Inhibiting p38 MAPK abrogated TCCM-mediated inhibition of MEK/ERK signaling and cytokine secretion. Western blot analysis showing protein levels of phosphorylated (p) and nonphosphorylated (A) ERK and MEK and (B) p38 and pATF-2 in normal (medium [Med]), TCCM-treated (TCCM), and TCCM- and SB203580-treated (TCCM+SB) cells. Lysates from d5 cultures of cells with or without the addition of TCCM and SB for 24 hours were prepared for the analyses. Representative results of 3 experiments are shown. Shown is cytokine expression in normal BMDCs (DMSO) and in SB203580 (SB)-treated, TCCM-treated, TCCM-, and SB-treated cells. (C) RT-PCR detecting cytokine mRNA expression in the cells. Representative results of 3 experiments are shown. (D) Cytokine array analysis showing the relative protein levels of cytokines in the culture medium of 5TGM1 myeloma cells and these cells. Results shown are the mean ± SD of 3 experiments. (E) ELISA detecting secreted TGF-β in TCCM and the culture media of these cells. Results shown are the mean ± SD of 3 experiments. ^*P < .05; ^**P < .01 (compared with normal controls).