Design,Synthesis And Primary Biological Studies Of Novel HDAC Inhibitors Based On Marine Phenylglycine Derivatives

Aim: In this study,the computer aid drug design system was used to modify the structure of marine natural products,in order to develop novel small molecules with potent anti-tumor activity targeted on HDAC.Methods: The program Sybyl and DS2.5 were used to establish the structure of HDAC3 and small molecules,while the docking was performed using“Gold.exe”.The picture of docking models could be seen by using Chimara program.After analyzing the combining model between designed compounds and HDAC3,the structure of compounds were modified again according to the docking results.Looking for relative reference and finding effective way to synthesis the compounds,the reaction routes were determined.In general,the amino-group was protected by Boc,and the Boc part is removed,after polyamides reaction.Various cap groups were introduced and the final compound was available after oximation.TCL method was performed to determine the purify of the compounds and the whether the raw material completely reacted,while the structure of compounds were determined by 1H-NMR.The HDAC inhibition assay was performed to determine the inhibition ability of each compounds.The results were discussed with docking model of each compounds,discovering the structure and activity relationship of HDACI.Then,the essential amino acid residue for enhancing HDAC inhibition ability of HDACI was clarified,while some advice which could enhance the anti-tumor activity of compounds were raised.CCK8 method was applied to determined the anti-proliferative activity of each compound against K562、U937、MDA-MB-231、PC3.At first,various cell lines were treated with 5 μM compounds,and the most potent agents were selected.Then,the IC₅₀ values of selected compounds against PC3、U937、MDA-MB-231、HL60、K562、SKOV-3 were determined.Results: According to the docking results,both designed compounds could combine with HDAC3.The linker part of compound entered into the channel of HDAC,while the hydroxamic acid could combine with Zinc at the end of the channel.The Cap group of compounds could generate molecule applied force with opening part of HDAC pocket.Only one fortis point was noticed in TCL plank,with trailing phenomenon.The phenomenon could disappear after adding a little acetic acid,while the point would become carmine if Fe Cl3 was added.All of these indicated that synthesized compounds are pure hydroxamate derivatives.The 1H-NMR results demonstrated that the structure of compounds were proper.The H signal of benzene ring in phenylglycine part was around 7.2-7.5,while C-H in phenylglycine was at 5.70.The H signal of dydroxamate acid appeared at 8.8 and 10.2,while the signals of –CH2 in linker part were found at 1.3,1.8 and2.8,respectively.In the in-vitro HDAC inhibition activity assay,the HDAC inhibition activity of lead compound HD1 with alkyne Cap structure was higher that O1,and weaker than other synthesized compounds(IC₅₀=13 μM).HD9 and HD10 displayed the most potent activity among the compounds,the IC₅₀ against HDAC were 76,108 nM,respectively,while the IC₅₀ value of positive control SAHA was 146 nM.Compounds with sulphonic acid amide structure showed less potency against HDAC compared with compounds with methane amide,demonstrating sulphonic acid amide structure could reduce the combine force between HDAC3 and molecule.Nonetheless,HD20 with tertButylbenzenesulfonamide displayed satisfying potency,and the IC₅₀ value was 0.17 μM.Introducing bromine in Cap group could enhance HDAC inhibition ability,while the effects were weaker if bromine was replaced by chlorine,nitrogroup and fluorine.The results of invitro anti-proliferation activity assay demonstrated that all of the compounds could inhibit the proliferation of tumor cell lines in low concentration（μM）,and the ability was influenced by HDAC enzymes potency.Interestingly,compounds were more sensitive to leukemia cell lines,which was in line with most published reference.HD9 was the most potent compounds,and the IC₅₀ values against U937,K562,HL60,MDA-MB-231,PC-3,SK-OV-3 were 0.51,0.83,0.76,2.94,3.66,3.17 μM,respectively,lower than SAHA.The inhibition ability of HD10 against leukemia cell lines was higher that SAHA,while the ability was inferior to SAHA against solid tumor cell lines.Conclusions: Some novel Phenylglycine derivatives targeted on HDAC were designed and synthesized,the presented compound HD9 displayed satisfying potency in HDAC inhibition assay and antiproliferative assay.