Histone deacetylase 1, 2, and 3 (HDAC1/2/3)

Histone deacetylase 1, 2, and 3 (HDAC1/2/3) are key members of the Class I histone deacetylase family, playing a fundamental role in the epigenetic regulation of gene expression [1, 6]. These zinc-dependent enzymes catalyze the removal of acetyl groups from lysine residues on both histone tails and various non-histone proteins, such as p53 and STAT3 [1, 3]. By promoting chromatin condensation, they typically act as transcriptional repressors within large multiprotein complexes like NuRD, Sin3, and CoREST [7, 13]. HDAC1 and HDAC2 are highly homologous and often functionally redundant in regulating cell proliferation and development, while HDAC3 plays a distinct role in both nuclear and cytoplasmic signaling pathways [13, 14]. Aberrant expression or activity of these isoforms is linked to the progression of various cancers, neurodegenerative disorders, and inflammatory diseases [1, 4, 8]. Therapeutic inhibition of HDAC1/2/3 by drugs like vorinostat and romidepsin leads to hyperacetylation, reactivation of tumor suppressor genes, and induction of apoptosis, making them critical targets in oncology and beyond [3, 12]. The development of isoform-selective inhibitors aims to improve therapeutic efficacy while minimizing the systemic toxicities associated with pan-HDAC inhibition [4, 7].

Other names

Class I HDACs (1-3)RPD3 homologsHDAC1HDAC2HDAC3Histone deacetylase 1Histone deacetylase 2Histone deacetylase 3

HDAC1, 2, and 3 inhibitors bind to the zinc-containing catalytic domain of these enzymes, repressing their deacetylase activity [1, 10]. This leads to the hyperacetylation of histones, which relaxes chromatin structure and allows for the reactivation of silenced genes, such as the cyclin-dependent kinase inhibitor p21 (WAF1/CIP1) [9, 12]. Additionally, inhibition affects the acetylation status of non-histone proteins like p53, STAT3, and chaperones, ultimately inducing cell cycle arrest, differentiation, and apoptosis in cancer cells [9, 12].