Histone deacetylase 1, 2, 3 (HDAC1, HDAC2, HDAC3)

Histone deacetylases 1, 2, and 3 (HDAC1, HDAC2, and HDAC3) are Class I zinc-dependent enzymes that serve as critical epigenetic regulators by removing acetyl groups from lysine residues on histone tails [2, 11]. This enzymatic activity promotes a condensed chromatin state, leading to the transcriptional repression of various genes involved in cell growth and survival [15]. Beyond histones, these HDACs also deacetylate non-histone proteins such as p53, E2F1, and STAT3, thereby modulating their stability and activity [12, 15]. In many pathological conditions, particularly cancer, these enzymes are frequently overexpressed, which results in the silencing of tumor suppressor genes and the promotion of oncogenic pathways [4, 18]. Therapeutic targeting of HDAC1, 2, and 3 with small-molecule inhibitors, such as vorinostat and romidepsin, has proven effective in treating certain hematological malignancies by inducing cell cycle arrest and apoptosis [3, 6]. Furthermore, HDAC2 and HDAC3 have been implicated in neurodegenerative disorders, where their inhibition may enhance synaptic plasticity and memory [10, 13]. However, the clinical application of these inhibitors is often associated with significant side effects, including myelosuppression and cardiotoxicity, necessitating the development of more selective agents [1, 3].

Other names

HDAC1HDAC2HDAC3Class I HDACsRPD3 homologsHistone deacetylase 1Histone deacetylase 2Histone deacetylase 3HD1RPD3L1

HDAC inhibitors bind to the zinc-containing catalytic domain of HDAC1, 2, and 3, preventing the removal of acetyl groups from lysine residues on histones and non-histone proteins [9, 19]. This leads to hyperacetylation, which relaxes chromatin structure and allows for the re-expression of silenced genes, such as the cyclin-dependent kinase inhibitor p21 [15, 16]. The resulting changes in gene expression and protein function trigger cell cycle arrest, differentiation, and apoptosis in malignant cells [15, 16].