KDM1/LSD1

KDM1A/LSD1 (lysine-specific demethylase 1A) is a flavin adenine dinucleotide (FAD)-dependent histone demethylase that catalyzes oxidative demethylation of histone H3K4me1/2 and H3K9me1/2, thereby regulating chromatin structure and transcriptional programs central to cell fate determination and differentiation^[1][2]. Mechanistically, LSD1 functions within transcriptional corepressor and chromatin-remodeling complexes, where its demethylase activity modulates epigenetic gene regulation and contributes to the dynamic control of gene expression^[2][3]. Through actions on both histone and non-histone substrates, LSD1 participates in multiple biological pathways involved in development, hematopoiesis, neuronal function, and cellular homeostasis^[3][4]. In disease settings, aberrant LSD1 activity supports cancer progression by regulating gene-expression programs associated with adaptation to the tumor microenvironment, epithelial-mesenchymal transition (EMT), stemness, and differentiation states^[4]. Experimental studies further demonstrate that pharmacological or genetic inhibition of LSD1 can suppress EMT-associated transcriptional programs and impede tumor progression in preclinical models^[4]. Compared with related isoforms, the neuronal LSD1 isoform displays distinct substrate specificity, preferentially demethylating H3K9me2 rather than H3K4me2 and promoting transcriptional programs linked to neuronal differentiation, learning, and memory^[4]. This functional divergence highlights isoform-specific biological roles that should be considered when interpreting mechanistic studies and therapeutic responses^[4]. For experimental applications, LSD1 has emerged as a major epigenetic drug target, and multiple small-molecule inhibitors, including tranylcypromine-derived compounds and clinical-stage LSD1 inhibitors, are being evaluated for hematologic malignancies and solid tumors, supporting its utility in target-validation and translational research programs^[4][5].