Inhibition of GSK-3 affects histone modification in CLL cells. (A-B) Twelve hours after treatment, genomic chromatin fragments from DMSO or 25 μmol/L AR-A014418 (ARA)-treated MEC1 cells (panel A) and malignant B cells from 5 patients with CLL (panel B) were immunoprecipitated with dimethyl-H3-K9, trimethyl-H3-K27, and dimethyl-H4-K20 antibodies. Immunoprecipitated chromatin was analyzed by PCR for the methylation of H3-K9, H3-K27, and H4-K20 at the XIAP and Bcl-2 promoters. PCR analysis on input chromatin (first 2 lanes) confirmed that equal chromatin amounts were used for ChIP. (C) Binding of NFκB p65 to the promoters of its target genes XIAP, and Bcl-2 was assayed in malignant B cells from a CLL patient treated with 25 μmol/L AR-A014418 (ARA) or 50 μmol/L Z-VAD-FMK (ZVAD) or AR-A014418 + Z-VAD-FMK for 12 hours by ChIP. Immunoprecipitated chromatin was also analyzed for the methylation of H3-K9, H3-K27, and H4-K20 at the XIAP and Bcl-2 promoters as described in (panels A and B).