Histone deacetylase 1, 2, 3 and 6 (HDAC1, HDAC2, HDAC3, HDAC6)

Histone deacetylases (HDACs) 1, 2, 3, and 6 are enzymes that catalyze the removal of acetyl groups from lysine residues on histones and non-histone proteins, thereby regulating gene expression and protein function (UniProt Q13547, Q92769, O15379, Q9UBN7). HDAC1, 2, and 3 are Class I HDACs primarily located in the nucleus, where they modulate chromatin architecture and transcriptional activity, while HDAC6 is a Class IIb enzyme that functions mainly in the cytoplasm, targeting substrates such as alpha-tubulin and Hsp90 (PubMed: 22429441). Overexpression or aberrant activity of these isoforms is linked to the progression of various malignancies, including cutaneous T-cell lymphoma and multiple myeloma, by suppressing tumor suppressor genes and promoting cell proliferation (NIH: StatPearls - Histone Deacetylase Inhibitors). Therapeutic targeting of these enzymes with HDAC inhibitors, such as Vorinostat and Panobinostat, induces hyperacetylation, leading to cell cycle arrest, differentiation, and apoptosis in cancer cells (PubChem CID: 5311). Beyond oncology, these targets are being investigated for roles in neurodegeneration and immune disorders due to their influence on protein stability and inflammatory signaling (PubMed: 30107315). However, clinical application is often challenged by side effects like thrombocytopenia and fatigue, necessitating the development of isoform-selective inhibitors to improve safety profiles.

Other names

HDAC1HDAC2HDAC3HDAC6Histone deacetylase 1Histone deacetylase 2Histone deacetylase 3Histone deacetylase 6RPD3HD1HD6Class I and IIb histone deacetylases

Inhibition of the enzymatic activity of histone deacetylases 1, 2, 3, and 6, which prevents the removal of acetyl groups from lysine residues on histones and non-histone proteins. This results in increased acetylation (hyperacetylation), leading to an open chromatin structure (euchromatin), reactivation of silenced tumor suppressor genes, induction of cell cycle arrest (typically at the G1/S phase), and activation of intrinsic and extrinsic apoptotic pathways (PubMed: 22429441, NIH: StatPearls).