Targeting a cryptic allosteric site of SIRT6 with small-molecule inhibitors that inhibit the migration of pancreatic cancer cells

SIRT6 belongs to the conserved NAD^(+)-dependent deacetylase superfamily and mediates multiple biological and pathological processes.Targeting SIRT6 by allosteric modulators represents a novel direction for therapeutics,which can overcome the selectivity problem caused by the structural similarity of orthosteric sites among deacetylases.Here,developing a reversed allosteric strategy Allo Reverse,we identified a cryptic allosteric site,Pocket Z,which was only induced by the bi-directional allosteric signal triggered upon orthosteric binding of NAD^(+).Based on Pocket Z,we discovered an SIRT6 allosteric inhibitor named JYQ-42.JYQ-42 selectively targets SIRT6 among other histone deacetylases and effectively inhibits SIRT6 deacetylation,with an IC50 of 2.33μmol/L.JYQ-42 significantly suppresses SIRT6-mediated cancer cell migration and pro-inflammatory cytokine production.JYQ-42,to our knowledge,is the most potent and selective allosteric SIRT6 inhibitor.This study provides a novel strategy for allosteric drug design and will help in the challenging development of therapeutic agents that can selectively bind SIRT6.

Tyrosine phosphatase SHP2 inhibitors in tumor-targeted therapies

Src homology containing protein tyrosine phosphatase 2(SHP2)represents a noteworthy target for various diseases,serving as a well-known oncogenic phosphatase in cancers.As a result of the low cell permeability and poor bioavailability,the traditional inhibitors targeting the protein tyrosine phosphate catalytic sites are generally suffered from unsatisfactory applied efficacy.Recently,a particularly large number of allosteric inhibitors with striking inhibitory potency on SHP2 have been identified.In particular,few clinical trials conducted have made significant progress on solid tumors by using SHP2 allosteric inhibitors.This review summarizes the development and structureeactivity relationship studies of the small-molecule SHP2 inhibitors for tumor therapies,with the purpose of assisting the future development of SHP2 inhibitors with improved selectivity,higher oral bioavailability and better physicochemical properties.

A multifunctional cross-validation high-throughput screening protocol enabling the discovery of new SHP2 inhibitors

The protein tyrosine phosphatase Src homology phosphotyrosyl phosphatase 2(SHP2) is implicated in various cancers, and targeting SHP2 has become a promising therapeutic approach. We herein described a robust cross-validation high-throughput screening protocol that combined the fluorescence-based enzyme assay and the conformation-dependent thermal shift assay for the discovery of SHP2 inhibitors. The established method can effectively exclude the false positive SHP2 inhibitors with fluorescence interference and was also successfully employed to identify new protein tyrosine phosphatase domain of SHP2(SHP2-PTP) and allosteric inhibitors. Of note, this protocol showed potential for identifying SHP2 inhibitors against cancer-associated SHP2 mutation SHP2-E76 A. After initial screening of our in-house compound library(w2300 compounds), we identified 4 new SHP2-PTP inhibitors(0.17%hit rate) and 28 novel allosteric SHP2 inhibitors(1.22% hit rate), of which SYK-85 and WS-635 effectively inhibited SHP2-PTP(SYK-85: IC_(50) Z 0.32 mmol/L;WS-635: IC_(50) Z 4.13 mmol/L) and thus represent novel scaffolds for designing new SHP2-PTP inhibitors. TK-147, an allosteric inhibitor, inhibited SHP2 potently(IC_(50) Z 0.25 mmol/L). In structure, TK-147 could be regarded as a bioisostere of the well characterized SHP2 inhibitor SHP-099, highlighting the essential structural elements for allosteric inhibition of SHP2. The principle underlying the cross-validation protocol is potentially feasible to identify allosteric inhibitors or those inactivating mutants of other proteins.

Strategies to overcome drug resistance using SHP2 inhibitors

Encoded by PTPN11,the SHP2(Src homology-2 domain-containing protein tyrosine phosphatase-2)is widely recognized as a carcinogenic phosphatase.As a promising anti-cancer drug target,SHP2 regulates many signaling pathways such as RAS-RAF-ERK,PI3 K-AKT and JAK-STAT.Meanwhile,SHP2 plays a significant role in regulating immune cell function in the tumor microenvironment.Heretofore,five SHP2 allosteric inhibitors have been recruited in clinical studies for the treatment of cancer.Most recently,studies have proved the therapeutic potential of SHP2 inhibitor in overcoming drug resistance of kinase inhibitors and programmed cell death-1(PD-1)blockade.Herein,we review the structure,function and small molecular inhibitors of SHP2,and highlight recent progress in overcoming drug resistance using SHP2 inhibitor.We hope this review would facilitate the future clinical development of SHP2 inhibitors.

Therapeutic potential of targeting protein tyrosine phosphatases in liver diseases

Protein tyrosine phosphorylation is a post-translational modification that regulates protein structure to modulate demic organisms’homeostasis and function.This physiological process is regulated by two enzyme families,protein tyrosine kinases(PTKs)and protein tyrosine phosphatases(PTPs).As an important regulator of protein function,PTPs are indispensable for maintaining cell intrinsic physiology in different systems,as well as liver physiological and pathological processes.Dysregulation of PTPs has been implicated in multiple liver-related diseases,including chronic liver diseases(CLDs),hepatocellular carcinoma(HCC),and liver injury,and several PTPs are being studied as drug therapeutic targets.Therefore,given the regulatory role of PTPs in diverse liver diseases,a collated review of their function and mechanism is necessary.Moreover,based on the current research status of targeted therapy,we emphasize the inclusion of several PTP members that are clinically significant in the development and progression of liver diseases.As an emerging breakthrough direction in the treatment of liver diseases,this review summarizes the research status of PTP-targeting compounds in liver diseases to illustrate their potential in clinical treatment.Overall,this review aims to support the development of novel PTP-based treatment pathways for liver diseases.

New techniques and strategies in drug discovery

Great success has been witnessed in last decades,some new techniques and strategies have been widely used in drug discovery.In this roadmap,several representative techniques and strategies are highlighted to show recent advances in this filed.(A)A DOX protocol has been developed for accurate protein-ligand binding structure prediction,in which first principle method was used to rank the binding poses.Validation against crystal structures have found that DOX prediction achieved an impressive success rate of 99%,indicating significant improvement over molecular docking method.(B)Virtual target profiling is a compound-centric strategy enabling a parallel implementation of interrogating compounds against various targets in a single screen,which has been used in hit/lead identification,drug repositioning,and mechanism-of-action studies.Current and emerging methods for virtual target profiling are briefly summarized herein.(C)Research on targeted autophagy to treat diseases has received encouraging progress.However,due to the complexity of autophagy and disease,experimental and in silico methods should be performed synergistically for the entire process.This part focuses on in silico methods in autophagy research to promote their use in medicinal research.(D)Histone deacetylases(HDACs)play important roles in various biological functions through the deacetylation of lysine residues.Recent studies demonstrated that HDACs,which possess low deacetylase activities,exhibited more efficient defatty-acylase activities.Here,we review the defatty-acylase activity of HDACs and describe examples for the design of isoform selective HDAC inhibitor.(E)The FDA approval of three kinase allosteric inhibitors and some others entering clinical study has spurred considerable interests in this targeted drug discovery area.(F)Recent advances are reviewed in structure-based design of novel antiviral agents to combat drug resistance.(G)Since nitric oxide(NO)exerts anticancer activity depending on its concentration,optimal levels of NO in cancer cells is desirable.In this minireview,we briefly describe recent advances in the research of NO-based anticancer agents by our group and present some opinions on the future development of these agents.(H)The field of photoactivation strategies have been extensively developed for controlling chemical and biological processes with light.This review will summarize and provide insight into recent research advances in the understanding of photoactivatable molecules including photoactivatable caged prodrugs and photoswitchable molecules.