Structure, expression,and induction of miR-29b in response to HDAC inhibition in CLL. (A) Structure of miR-29a-b and miR-29b-c genes. (B) Levels of miR-29b as measured by quantitative RT-PCR and normalized to the levels of RNU6B used as a loading control in lymphocytes (total and CD19⁺ B cells) from normal donors and 46 CLL samples. The data were then expressed as a percentage of the values obtained for one arbitrarily chosen normal set at 1. Statistical analysis was conducted using ANOVA; mean values of miR-29b was significantly different between normal lymphocytes and CLL lymphocytes that showed a 60% or greater decrease in expression (***P < .001). (C) Increase in the levels of the H3K4me2 modification at the miR-29b promoter in a representative CLL sample after exposure to 10nM LBH589 for 5 hours. (D) Induction of miR-29b in the same CLL samples after exposure to 10nM LBH589 for 5 hours. The -fold increase after exposure to LBH589 was calculated and is represented as increase in levels of expression (as determined in Figure 4B) over that in untreated cells. (E) Induction of miR-29b in 46 CLL samples on HDAC inhibition. (F) Induction of miR-15a and miR-16 in a CLL sample after exposure to the HDAC inhibitors SAHA (3μM) and MS275 (3μM) for 3-6 hours.