A class of substances known as histone deacetylase (HDAC) inhibitors controls the activity of the enzymes responsible for deacetylating histones. By eliminating acetyl groups from lysine residues on histone proteins, these enzymes condense chromatin structure and suppress gene transcription, which is a critical function they perform in gene regulation. Since they may be able to treat a wide range of illnesses, including cancer, neurological ailments, and inflammatory problems, HDAC inhibitors have attracted a lot of attention. Histone acetylation, which causes chromatin relaxation and increases DNA accessibility to transcription factors and other regulatory proteins, is one of the main ways that HDAC inhibitors work. This change in chromatin shape makes it easier for genes involved in differentiation, apoptosis, cell cycle regulation, and DNA restoration. HDAC inhibitors have the ability to cause apoptosis, differentiation, and cell cycle arrest in cancer cells, which in turn prevents tumor development and spread. Preclinical and clinical research have been conducted to develop and assess a number of HDAC inhibitors. Among these are entinostat (MS-275), belinostat (PXD101), panobinostat (LBH589), romidepsin (FK228), and vorinostat (suberoylanilide hydroxamic acid). The selectivity of these inhibitors for distinct HDAC isoforms varies, which may have an impact on their safety and therapeutic efficacy. HDAC inhibitors have been researched for their potential to cure different disorders in addition to their promising anticancer activity. For example, HDAC inhibitors have demonstrated neuroprotective effects in neurodegenerative illnesses such as Alzheimer's and Parkinson's disease by increasing promoting synaptic plasticity, decreasing neuroinflammation, and maintaining neuronal survival. HDAC inhibitors have also shown anti-inflammatory qualities in diseases like inflammatory bowel disease and rheumatoid arthritis, where they alter immune cell activity and limit the synthesis of pro-inflammatory cytokines. However, toxicity, off-target effects, and resistance mechanisms are some of the reasons that restrict the clinical value of HDAC inhibitors. HDAC inhibitor side effects that are frequently reported include thrombocytopenia, nausea, diarrhea, and exhaustion. Moreover, a number of processes, including modifications in drug metabolism, adjustments in target expression, and the initiation of compensatory signaling pathways, might result in resistance to HDAC inhibitors. In summary, HDAC inhibitors are a promising family of drugs with a wide range of uses in treating cancer and other illnesses. More investigation is required to maximize their safety, efficacy, and selectivity profiles as well as to find biomarkers that can predict patient response and direct individualized treatment plans.
