6-OAP overcomes the protective effects of IL-6, IGF-I and BMSCs on MM cells.

<p>(A and B) MM.1S cells were cultured for 48 h with indicated concentrations of 6-OAP at the presence or absence of IL-6 (A) or IGF-I (B). Cell proliferation was assessed by MTT assay. (C) MM.1S and/or BMSCs cells were cultured for 48 h with indicated concentrations of 6-OAP. Cell proliferation was assessed by MTT assay. *<i>p</i><.01,** <i>p</i><.05. (D) MM.1S cells were serum starved for 2 h, then co-cultured without or with 6-OAP at 5 µM for 12 h, followed by stimulation with IL-6 at 10 ng/ml for indicated time points (upper panel), or IL-6 at 10 ng/ml for 1 h, followed by treatment with 6-OAP at indicated concentration for 12 h (lower panel). Whole-cell extracts were prepared and examined by Western blotting using antibodies against pJak2, pStat3, Stat3 or β-actin. (E) MM.1S cells were serum starved for 2 h, then co-cultured without or with 6-OAP (5 µM) for 12 h, followed by stimulation with IGF-I at 50 ng/ml for indicated time points (upper panel), or stimulated with IGF-I at 50 ng/ml for 1 h, followed by treatment with 6-OAP at indicated concentration for 12 h (lower panel). Whole-cell extracts were prepared and examined by western blotting using antibodies against pPDK1, pAkt, Akt or β-actin. (F) MM.1S cells were serum starved for 2 h, then co-cultured without or with 6-OAP (5 µM) for 12 h, followed by stimulation with TNF-α at 5 ng/ml for indicated time points. Whole-cell extracts were prepared and examined by Western blotting using indicated antibodies.