Abstract
Background: Acute promyelocytic leukemia (APL) and acute lymphoblastic leukaemia (ALL) are often presented with loss of H4K16 monoacetylation (ac) and H4K20 trimethylation (3Me) due to increased activity of Class I HDAC’s. In the current study we explored the efficacy and mechanistic basis of a novel Class I HDAC inhibitor SBAK-GHA across different leukemic cell lines and characterised the distinct acetylation pattern on histone H3 and H4.Methods: We initially performed general and class specific HDAC enzyme activity assays to establish the effect of our lead molecule SBAK-GHA. Following, we have probed various acetylation sites to understand a thorough acetylation profile of various leukemic cell lines by immunoblotting. Next, to understand the effect of various Class 1 HDAC isoforms on acetylation levels of hallmark proteins in leukaemia; lentiviral knockdown approach was carried out. In addition, cell cycle analysis was also done to distinguish the pattern of cell cycle phase arrest, followed by Chip-qPCR studies of various cyclins and their relationship with cell cycle arrest. Finally, an in vivo study was performed to confirm the anti-leukemic activity of SBAK-GHA by using specific leukaemia models.Results: SBAK-GHA showed class I HDAC inhibitor activity specifically targeting HDAC 2. SBAK-GHA treatment upregulates H4K16 ac and H4K20 me3 in variety of leukemic cell lines. Similar results were found during knock down of HDAC2 in leukemic cell lines. Moreover, we also observed a coherence of events like cell cycle arrest across different cell types of leukemias and modulation in the levels of acetylation across different cyclin promoters. Further on, studies in various in vivo cancer models demonstrated SBAK-GHA to be highly selective towards lymphocytic leukaemia.Conclusion: Our data provided a basic overview of relationship between different class I HDAC isoforms and their possible roles in regulation of histone acetylation in pathogenesis of leukaemia. Our study here presented multiple evidences regarding SBAK-GHA as a novel HDAC2 inhibitor. SBAK-GHA resist leukemogenesis mainly by inducing the repressed H4K16 ac and H4K20 me3. Further, the results in present study had established a relationship between class I HDAC isoforms and their possible roles in regulation of histone acetylation in pathogenesis of leukaemia.
The Class I Hdac Inhibitor Mgcd0103 Induces Cell Cycle Arrest and Apoptosis in Colon Cancer Initiating Cells by Upregulating Dickkopf-1 and Non-Canonical Wnt Signaling