Design,Synthesis And Biological Evaluation Of 4-Piperidin-4-yl-Triazole Derivatives As Novel Histone Deacetylase Inhibitors

Objective:histone deacetylase（HDAC）is an important target for drug design and discovery in cancer therapy.In this study,we designed and synthesized hydroxamic acid derivatives with the 4-piperidin-4-yl-triazole as the core by means of medicinal chemistry and organic chemistry,so as to obtain novel HDAC6 selective inhibitors with potent anti-tumor activities.Methods:in this work,we designed 21 target compounds with4-piperidin-4-yl-triazole as the core via rational drug design.And,we smoothly gotthe target compounds via organic synthesis processes including the reactions of Boc protection,Click reaction,Boc deprotection,amide formation,and hydroxylamine condensation,etc.;we preliminarily monitored the purity of target compounds through TLC and staining with ferric chloride;we further confirmed their structures and the purity by ¹H-NMR,¹³C-NMR and MS;we investigated the inhibitory activity of all target compounds against HDACs and the selectivity of two representative compounds MH1-18 and MH1-21 towards HDAC1 and 6 by utilizing the HDAC fluorometric drug screening kit;we evaluated the anti-proliferative activities of compounds MH1-18 and MH1-21 against three human tumor cells SGC-7901,NCI-H226 and HL-60 by MTT method;we also investigated the anti-angiogenic activity of MH1-18 by using the phase-contrast microscope;And we investigated anti-migration effect of MH1-21 against MCF-7 cells at three concentrations of 12.5μM,25.0μM,50.0μM,respectively by utilizing the inverted phase contrast microscope and ImageJ;finally,we utilized docking simulations to propose the binding modes of compounds MH1-18 and MH1-21 with HDAC6 by utilizing the software of Tripos SYBYL-X 2.1.Results:all structures of 21target compounds were confirmed by¹H NMR,¹³C NMR and MS.The result of in vitro HDAC enzyme inhibitory activity test showed that compound MH1-18 and MH1-21could potently inhibit HDACs at the concentration of 1μM,and the inhibition rates were93.6%and 92.7%,respectively,while the inhibition rate of the positive control SAHA was 96.3%.The result of in vitro HDAC enzyme isoform selectivity test showed that the compound MH1-18 and MH1-21 exhibited strong inhibitory activities against HDAC6with the IC₅₀0 values of 11.5 nM and 8.6 nM,respectively,while their inhibitory effects on HDAC1 were relatively low,the IC₅₀0 values were 119.2 nM and 105.6 nM,respectively,so the selectivity factors to HDAC6 of compounds MH-18 and MH-21 were 10.4 and12.3,respectively,better than that of ACY1215.The result of in vitro anti-proliferative activity results showed that MH1-18 and MH1-21 exhibited some selectivity toward blood tumor cell HL-60 over other two solid tumor cells.The in vitro anti-angiogenic test result showed that the compound MH1-18 exhibited a stronger anti-angiogenic activity than the positive control drugs SAHA and ACY1215 at a concentration of 40μM.The in vitro anti-migration test result showed that the compound MH1-21 could significantly suppress the migratory capabilities of MCF-7 cells at concentrations of 12.5μM,25.0μM,and 50.0μM compared with the blank control group.Conclusion:In this study,we designed and synthesized 21 hydroxamic acid derivatives with the4-piperidin-4-yl-triazole as core as novel HDAC6 selective inhibitors.The two representative compounds MH1-18 and MH1-21 both exhibited anti-tumor potency.