Desigh,Synthesis And Preliminary Activity Evaluation Of IAPs Antagonist

Apoptosis is critical to the normal development and homeostasis of multicellular organisms.It has been linked to many human diseases,including cancer.IAPs(Inhibitor of apoptosis proteins)are a class of key regulators in apoptotic pathways and have been discovered as a new potential target for treating cancer in recent years.It has been demonstrated that IAPs are over expressed in many cancer cells such as ovarian cancer,breast cancer,prostate cancer and so on.They block apoptotic pathways to ensure cancer cell survival.In addition,IAPs are also a fundamental reason for causing a variety of cancer cells resistant to chemotherapy drugs.Therefore,the antagonist of IAPs plays an efficient role in treating cancer.So far,a variety of different structures of IAPs antagonists have been reported and demonstrated their activity of anticancer.Six of compounds,GDC-0152,GDC-0917,SM-406,LCL161,HGS1029,TL32711have entered clinical trial.Bivalent antagonists TL32711 has entered phase II clinical trial,and other IAPs antagonists have entered clinical phase I.Combining the modeling method of computer-assisted drug design and the structures of IAPs antagonists reported in literature,a basically structural pattern of small molecular IAPs antagonist was proposed in this research.We analyzed the critical structural characteristic of interaction between endogenous antagonist Smac and XIAP-BIR3.Based on this information above,a series of target compounds were designed.In this research,seven different synthetic strategies were chosen to prepare these compounds and 36 compounds were synthesized using these seven strategies.These compounds are not reported so far in the literatures and their structures were confirmed by 'H-NMR and LC-MS.The reaction condition of every step including in the synthetic strategies was investigated in detail.Especially,a suitable synthetic method of critical intermediate 1 was found in the research.The binding assays of these target compounds with XIAP-BIR3,XIAP-BIR2-BIR3 and cIAPl/2-BIR3 were carried out by using fluorescence polarization anisotropy(FPA)competitive test.The results as follows:1)Most of these target compounds have antagonistic activity aganist XIAP-BIR3,the IC50 values of eight compounds are in the range of 0.1-1 ?M;2)Most of these target compounds have antagonistic activity aganist XIAP-BIR2-BIR3,the IC50 values of five compounds are in the range of 10-100 nM;the IC50 values of four compounds are under 10nM;3)Most of these target compounds have antagonistic activity aganist cIAPl/2-BIR3,the IC50 values of six compounds are under 100nM.A WST-8 method was employed to evaluate inhibitory activity of target compounds on SK-OV-3 ovarian cancer cells and MDA-MB-231 breast cancer cells in vitro.The results showed that two compounds WX20120621 and WX20120521 inhibits SK-OV-3 cancer cell growth with rate 85.4%and 70.0%at 1?M·L-1 while paclitaxel is 76.8%at the same conditions.Twelve compounds IA-1?IA-2?IIA-2?IIB-7?IIB-11?IIB-12??-1??-2??-3??-4??-1??-2 inhibits MDA-MB-231 cancer cell growth with rate 70.9%,64.4%,58.3%,59.7%,94.0%,76.4%,83.5%,83.9%,85.7%,91.1%,61.4%and 69.0%at 1?M·L-1 while paclitaxel is 38.5%under the same conditions.According to the results of preliminary activity evaluation,the SAR of the target compounds were analyized.These conclusions will give a foundation for the structural optimization of these IAPs antagonists.