BMP7 up-regulates NDRG1 through activation of p38. (A) PC3 mm cells were grown in the presence of HS5-CM with 3 µg/ml BMP inhibitor Noggin (+) or vehicle (−), and the expression of NDRG1, p-p38, p38, and β-tubulin was examined by Western blot and qRT-PCR (n = 3; *, P < 0.05 vs. first bar; #, P < 0.05 vs. second bar). (B) The effect of BMP2, BMP4, BMP5, BMP6, BMP7, and FGF2 on the expression of p-p38, p38, p21, p27, NDRG1, and β-tubulin in PC3 mm and DU145 cells was examined by Western blot. (C) LNCaP, C4, C4-2, C4-2B, and ALVA were cultured with or without 200 ng/ml BMP7, and the expression of p-p38, p38, and β-tubulin was examined by Western blot. (D) The effect of the indicated concentrations of BMP7 on NDRG1 expression in PC3 mm and DU145 was examined by qRT-PCR (n = 3; *, P < 0.05). (E) The effect of the indicated concentrations of BMP7 on the expression of NDRG1 in PC3 mm was examined by NDRG1 reporter assay (n = 3; **, P < 0.01; ***, P < 0.001). (F and G) Western blot for BMP7 in the CM from bone stromal cells (hBMSC, hFOB1.19, and HS5) and prostate cancer cells (PC3 mm, DU145, C4-2B, and ALVA; F) or CM from HS5 that had either scrambled shRNA (scramble) or shRNA for BMP7 (shBMP7; G). (H) PC3 mm cells were cultured with the CM from HS5/scramble or HS5/shBMP7, and the expression of p-p38, NDRG1, p21, and β-tubulin was examined by Western blot. (I and J) PC3 mm cells were treated with or without 200 ng/ml BMP7 in the presence or absence of 10 µM of the p38 inhibitor SB203580 (SB), and the expression of NDRG1 was examined by qRT-PCR (I) and by NDRG1 reporter assay (J; n = 3; *, P < 0.05; **, P < 0.01; ***, P < 0.001). All experiments were performed three times independently, and representative data are shown. Results are shown as mean ± SEM.