The aim of this study was to detect the alterations in histone methylation and acetylation in patients with chronic lymphocytic leukemia (CLL). Global histone H3/H4 acetylation and H3K4/H3K9 methylation were detected by the EpiQuik™ global histone H3/H4 acetylation and H3K4/H3K9 methylation assay kits. The mRNA expression of selected chromatin modifier genes was measured by real-time polymerase chain reaction (RT-PCR). Our results found that the global histone H3/H4 hypoacetylation in the CD19+ B cells of patients with CLL (P=0.028 and P=0.03, respectively) and the global histone H3K9 methylation in patients with CLL were significantly increased compared with controls (P=0.02), while there was no significant difference in the global histone H3K4 methylation between the two groups. The level of SIRT1 and EZH2 mRNA expression was upregulated in patients with CLL (P=0.03 and P=0.02, respectively), which increased significantly with progression from Binet stage A to stage C (P=0.015 and P=0.01, respectively) and Rai good to high risk stage (P=0.007 and P=0.008, respectively). The level of HDAC1 and HDAC7 mRNA expression was significantly increased (P=0.02 and P=0.008, respectively) and HDAC2 and P300 mRNA expression was reduced in patients with CLL (P=0.002 and P=0.001, respectively). In conclusion, it is observed that the aberrant histone modification plays an important role in the pathogenesis of CLL.
Keywords: CLL; EZH2; SIRT1; histone acetylation; histone methylation.