Structure-based Design,Synthesis And Biological Evaluation Of Novel Akt Inhibitor And Proteolytic Targeting Chimera

Activation of the PI3K/Akt pathway is common in the development and malignant proliferation of various types of tumours,and Akt(also known as protein kinase B)is central to the PI3K/Akt/mTOR signalling pathway.Targeted inhibition/degradation of Akt proteins is considered as a potential therapeutic strategy for cancer treatment.In this thesis,based on the group’s previous research,the design,synthesis and anti-tumour activity of novel structure-based ATP-competitive Akt inhibitors and protein hydrolysis-targeted chimeras(PROTAC)were carried out as follows:Design,synthesis and bioactivity studies of novel phenyl-pyrazole Akt inhibitors.ATP-competitive inhibitors were the most widely studied class of Akt inhibitors,which act competitively with ATP in the ATP-binding pocket and impede its phosphorylation of substrate proteins.Since Akt belongs to the same AGC protein family as PKA,PKC,ROCK,etc.,their ATP binding pockets are highly similar,which poses a great challenge for designing specific Akt inhibitors.In our group,we found two phenyl-pyrazole derivatives,D19 and D22,showed high Akt1 inhibitory activity and low h ERG inhibitory ability in our previous study.Through protein docking we found that the biggest difference between compounds D19 and D22 and the positive compound GSK-795 is the distance to Glu278 which cannot form an effective hydrogen bonding interaction.Interestingly,we found that when halogen substituents were introduced into the benzene ring,the dihedral angle between the amide and benzene ring was increased,thus shortening the distance between the piperidine ring and Glu278 to form an effective hydrogen bonding linkage.Based on this finding,20 novel Akt inhibitors were designed and synthesized in this thesis.The results of activity tests showed that most of the compounds exhibited high Akt1 inhibitory activity,and some of them showed high cytotoxicity against all three tumor cell lines,HGC-27,786-O and KHOS,and also exhibited low h ERG inhibition.The representative compounds A3 and A16 showed optimal bioactivity and have potential for further development.Design,synthesis and bioactivity studies of novel protein hydrolysis-targeted chimeras.Akt protein has multiple Lysine residues distributed on its surface,which can be ubiquitinated under normal conditions catalyzed by various E3 ubiquitin ligases and thus degraded in the proteasome.Currently,this process can be artificially facilitated using protein hydrolysis-targeted chimera(PROTAC)technology.In this thesis,19 PROTAC molecules were designed and synthesized based on two compounds,1-192 and 1-215,discovered by the group earlier.The bioassay results showed that most of the compounds maintained high Akt inhibitory activity,and compounds D2 and D5 possessed significant ability to degrade Akt proteins and exhibited good cytotoxicity.We further simulated the binding mode of representative compounds D2 and D5 forming ternary complexes with Akt and CRBN by calculation,which provided a structural basis for further structural modification and optimization of drug-forming properties.In summary,this thesis takes Akt protein as a starting point to explore the discovery and optimization of its inhibitor and protein degradation chimeric molecules,and provides new ideas and experimental basis for new therapeutic strategies using Akt as an anti-tumor target.