Histone deacetylases as an epigenetic pillar for the development of hybrid inhibitors in cancer

The polypharmacology strategy of multi-targeting drugs acting on different biological pathways is capturing the researchers’ attention, particularly in cancer. The simultaneous inhibition of two or more targets by drug combination or by a single ‘hybrid molecule’ can provide improved therapeutic efficacy when compared to the one-target inhibitors. In this regard, because of their multiple anticancer effects, histone deacetylase inhibitors have become a privileged tool for the development of hybrid drugs. The clinical trials of two multi-acting chimeras, HDAC/EGFR/HER2 and HDAC/PI3K inhibitors, encouraged the design of novel hybrids, such as compounds 22a (LSD1/HDAC) and 16a (CDK4/JAK1/HDAC), which showed superior anticancer effects than single-targeting agents or their combination both in cellular and mouse models