SAHA rapidly decreased cyclin D1 protein in MCL cells. (A) Jeko1 cells (MCL line) and K562 cells (AML line) and (B) 2 other MCL cell lines (SP49, SP53) were cultured with SAHA (5 μM) for the indicated times, and cyclin D1 and β-actin protein levels were measured by Western blot analysis. (C) Jeko1 cells were treated with either TSA (150 nM), VPA (5 mM), or NaBu (1 mM) for the indicated times and analyzed for expression of cyclin D1 and β-actin by Western blot. (D) Jeko 1 cells were treated with HDAC inhibitors (SAHA, VPA, NaBu, TSA) or 5FU at indicated concentrations for 7 hours. Levels of cyclin D1, acetyl-histone H3 (a known target of SAHA), and β-actin (loading control) were examined by Western blot analysis.