Design,Synthesis And Preliminary Bioactivity Evaluations On Novel Benzenesulfonamide Derivatives As Bcl-2 Inhibitors

As an important drug fragment,Benzenesulfonamide has a variety of biological activity.It applied as antibacterial in the clinical for several decades.With the research advance,it was found that it had a wider range of biological activities,such as diuresis,anti-thyroid,resistance to diabetes,etc.In recent years,a large amount of N-substituted Benzenesulfonamide compounds with antitumor activity was reported.Some of them were studied in clinical trail.These anti-tumor candidates have different targets,for example,carbonic anhydrase inhibitors,histone deacetylase inhibitors,microtubule protein inhibitors,Bcl-2 protein inhibitors,protein kinase inhibitors and so on.Based on literatures research,computer-aided drug design and our previous studies,two different types of N-substituted Benzenesulfonamide derivatives,were designed and synthesized respectively in order to discover new Benzenesulfonamide compounds with Bcl-2 protein inhibitory activity.The first type of target compounds.N-phenylpiperazine substituted Benzenesulfonamide derivatives,was designed based on the character of crystal structure of Bcl-2 protein binding with ABT-737.Meantime,the structure-activity relationship of different electrical substituents to mother nucleus 1-(phenylsulfonyl)piperazine were evaluated.Different groups of aryl ether or benzofuran group were introduced into the phenyl ring to investigate the change of their bioactivities.In the other hand,during the molecular docking,keeping the original groups of phenylpiperazine and 4-chlorobiphenyl in the structure of ABT-737 unchanged,the Benzenesulfonamide fragment was removed to obtain another type of simplied structure of ABT-737.The influence of the substitutes in the phenyl ring connecting to piperazine structure,was evaluated by introducing diverse groups,such as nitro group,amine group and aminosulfonyl group.Totally,twenty target compounds were synthezied and then evaluated for their antiproliferative activities against tumor cells using MTT method and Bcl-2 binding test based on fluorescence polarization method.The results showed most of target compounds exhibited poor binding affinities with Bcl-2 proteins.One target compound,compound 20.had good inhibition on some tumor cell lines.For example,this compound showed similar antiproliferative activity against human breast cancer cell line MDA-MB-231,compared with the positive control.The second type of target compounds,hydantoin Benzenesulfonamide derivatives in this paper,was designed based on the previous SAR studies of WL-276,a Bcl-2 protein inhibitor.In order to develop novel Bcl-2 inhibitors,rhodanine ring of WL-276 was replaced by the hydantoin structure according to the principle of bioisosterism.Meanwhile,different substitutents and bond saturation of side chain were tried.The synthesized thirty target compounds were tested the binding affinity to Bcl-2 protein with fluorescence polarization method.Five compounds(34,35,37,38 and 43)with best binding affinity were chosen to evaluate their binding affinities to Bcl-xL?Mcl-1.The result indicated that compound 34 and 38 had similar binding affinity to all 3 proteins.While compound 35 and 37 showed poor ability to bind Bcl-xL and Mcl-1,which indicated that these two compounds had the binding selectivity on Bcl-2.Further antiproliferative activities were performed on these five active comounds using three tumor cell lines,chronic myeloid leukemia K562 cells,human prostate cancer cells PC-3 and human breast cancer cells MDA-MB-231.All the five compounds possessed good inhibition on these three tumor cell lines.Among them,34 and 38 were better than others.Especially comound 38 showed more potent antiproliferative acitvitis against K562 and PC-3 compared with lead compound WL-276.In summary,totally sixty-eight new compounds were synthesized,which included eighteen new intermediates and fifty new target compounds.The structures of all target compounds were identified through melting point,1H-NMR and high resolution mass spectrometry analysis.For intermediates,the structures were confirmed by 1H-NMR and electrospray mass spectrometry ESI-MS.The analysis of the biological activity and structure-activity relationship of the two types of N-substituted Benzenesulfonamide derivatives will contribute to develop new Benzenesulfonamide compounds as Bcl-2 protein inhibitors with better activities.