miRNA-9* regulates proliferation and survival in WM cells as well as in low-grade lymphoma IgM-secreting cells. (A) WM cells (A: BCWM.1), low-grade lymphoma IgM-secreting cell lines (B: MEC1; C: RL; scramble probe–, precursor (pre)–miRNA-9*–transfected, and untransfected) were harvested at 24, 48, and 72 hours after transfection; DNA synthesis and cytotoxicity were assessed by thymidine uptake and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, respectively (*P < .05). (D) Cell cycle analysis was performed by propidium iodide staining with BCWM.1 cells (untransfected, scramble probe–, and pre-miRNA-9*–transfected). (E) BCWM.1 cells (untransfected, scramble probe–, and pre-miRNA-9*–transfected) were harvested at 12 hours after transfection. Whole-cell lysates were subjected to Western blotting with anti-p21 and -actin antibodies. (F) Freshly isolated normal CD19⁺ cells from normal PBMCs were cultured with LBH589 (0-80nM) for 48 hours. Cytotoxicity was assessed by MTS assay.