Design,Synthesis And Activity Analysis Of HDACs Inhibitors

With the incidence and mortality of cancer increasing year by year,the prevention and treatment of cancer to be a hot topic.Epigenetic modifications of chromatin are currently considered to play an important role in the development and progression of tumor cells.Among them,histone acetylation is an important modification.The balance of histone acetylation status is based on the HATs and HDACs,and the above two enzymes act simultaneously and antagonize.When HDACs are overexpressed,the level of acetylation is unbalanced,and the transcription of the tumor suppressor gene is inhibited,which leads to the development of tumor cells.The HDACIs are able to inhibit overexpression of HDACs and promote a homeostatic level of histone acetylation.HDACIs have the effects of inducing tumor cell apoptosis,blocking tumor cell growth,and blocking angiogenesis,which makes HDACIs more promising and potential in the design and development of anticancer drugs.HDACIs have a wide variety of drug structures,and many HDACIs and their derivatives are designed and synthesized for clinical trials.Chidamide is a comprehensive targeted anti-tumor drug with a new chemical structure approved for sale in January 2015.In this paper,retaining the chemical structure of the mental binding domain of Chidamide.In order to increase the interaction between the HDACIs and the surface of the HDACs enzyme pocket and to ensure that the metal binding domain of HDACIs reaches the bottom of the enzyme pocket and Zn²⁺,designed 4 different surface recognition domains and14 different linker domians.At the last,56 compounds were obtained by combination.Screening was performed using computer simulation molecular docking software,Autodock4.2,and 8 target compounds with relatively free binding energy were selected.The selected 8target compounds were synthesized by peptide liquid phase synthesis method,and the synthesized compounds were identified as target compounds by high performance liquid chromatography and mass spectrometry,and their purity were above 97%.In order to test the inhibitory activity of the target compound,using HDACs and HDAC2 inhibitory activity assay fluorescent kit.The results showed that the eight target compounds have good inhibitory activity against holoenzyme HDACs and HDAC 2,and their enzyme inhibitory activities are selective for class I HDACs.Among them,the target compounds Y2and Y4 were the strongest,and their IC₅₀ of HDACs were 0.114μM and 0.089μM,and their IC₅₀ of HDAC 2 were 0.216μM and 0.188μM.In order to further clarify the structure-activity relationship between inhibitors and enzymes,hydrogen bonding analysis was performed using Pymol software.Among them,Y4 and Y8 have more strong hydrogen bonding,which corresponds to the results of in vitro inhibition of enzyme activity.They generate 4 and 6 hydrogen bonds with HDAC 2,and the chelation of 379 Zn²⁺in HDAC 2and 2502 Zn²⁺in HDAC 6 was achieved by strong electrostatic interaction.By comparison,it was found that the introduction of phenyl groups in the surface recognition domain can increase the inhibitory activity of the compounds.In the linking chain domain,the addition of a methyl group can also increase the inhibitory activity of the compound,but excessive addition of a methyl group will cause steric hindrance to favor the binding of the compound to the enzyme.