bix-01294 and Leukemia--Myelogenous--Chronic--BCR-ABL-Positive

Myeloid leukemia treatment is quite successful nowadays; nevertheless the development of new therapies is still necessary. In the present study, we investigated the potential of epigenetic modulators EGCG (epigallocatechin-3-gallate) and BIX-01294 (N-(1-benzylpiperidin-4-yl)-6,7-dimethoxy-2-(4-methyl-1,4-diazepan-1-yl)quinazolin-4-amine) to alter epigenetic state and cause cellular senescence in acute and chronic myeloid leukemia NB4 and K562 cells. We have shown that after leukemia cell treatment with EGCG and BIX-01294 the proliferation and survival were inhibited of both cell lines; however, only NB4 cells underwent apoptosis. Both epigenetic modulators caused cell cycle arrest in G0/G1 phase as assessed by RT-qPCR (p53, p21, Rb) and flow cytometry analysis. Increased levels of ATM, HMGA2, phosphorylated ATM, and SA-β-galactosidase staining indicated that EGCG caused cellular senescence, whereas BIX-01294 did not. Immunoblot analysis of epigenetic players DNMT1, HP1α, H3K9me3, EZH2, and SUZ12 demonstrated beneficial epigenetic modulation by both agents with exception of mainly no epigenetic changes caused in K562 cells by EGCG. Therefore, we suggest EGCG as a promising epigenetic modulator for acute promyelocytic leukemia therapy and as a potential cellular senescence inducer in both acute and chronic myeloid leukemia treatment, whereas BIX-01294 could be beneficial as an epigenetic modifier for both myeloid leukemias treatment.

Topics: Antineoplastic Agents; Azepines; Catechin; Cellular Senescence; Chromobox Protein Homolog 5; Drug Screening Assays, Antitumor; Epigenesis, Genetic; G1 Phase Cell Cycle Checkpoints; Gene Expression Regulation, Neoplastic; Humans; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Promyelocytic, Acute; Quinazolines

H3K9 methylation is one of the essential histone post-translational modifications for heterochromatin formation and transcriptional repression. Recently, several studies have demonstrated that H3K9 methylation negatively regulates the type I interferon response.. We report the application of EHMT1 and EHMT2 specific chemical inhibitors to sensitize CML cell lines to interferon and imatinib treatments. Inhibition of EHMT1 and EHMT2 with BIX01294 enhances the cytotoxicity of IFNα2a in four CML cell lines, K562, KCL22, BV173 and KT1 cells. Chromatin immunoprecipitation assay shows that BIX01294 treatment enhances type I interferon response by reducing H3K9me2 at the promoters of interferon-stimulated genes. Additionally, BIX01294 treatment augments IFNα2a- and imatinib-mediated apoptosis in CML cell lines. Moreover, our data suggest that the expression level of EHMT1 and EHMT2 inversely correlates with the type I interferon responsiveness in CML cell lines.. Our study sheds light on the role of EHMT1 and EHMT2 as potential targets in improving the efficacy of standard treatments of CML.

Topics: Antineoplastic Agents; Apoptosis; Azepines; Benzamides; Cell Proliferation; Drug Synergism; Gene Expression; HeLa Cells; Histocompatibility Antigens; Histone-Lysine N-Methyltransferase; Humans; Imatinib Mesylate; Interferon Type I; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Piperazines; Pyrimidines; Quinazolines