title: Targeted Covalent Inhibition of Grb2-Sos1 Interaction through Proximity-Induced Conjugation in Breast Cancer Cells.
abstract: Targeted covalent inhibitors of protein-protein interactions differ from reversible inhibitors in that the former bind and covalently bond the target protein at a specific site of the target. The site specificity is the result of the proximity of two reactive groups at the bound state, for example, one mild electrophile in the inhibitor and a natural cysteine in the target close to the ligand binding site. Only a few pharmaceutically relevant proteins have this structural feature. Grb2, a key adaptor protein in maintaining the ERK activity via binding Sos1 to activated RTKs, is one: the N-terminal SH3 domain of Grb2 (Grb2N-SH3) carries a unique solvent-accessible cysteine Cys32close to its Sos1-binding site. Here we report the design of a peptide-based antagonist (a reactive peptide) that specifically binds to Grb2N-SH3and subsequently undergoes a nucleophilic reaction with Cys32to form a covalent bond thioether, to block Grb2-Sos1 interaction. Through rounds of optimization, we eventually obtained a dimeric reaction reactive peptide that can form a covalent adduct with endogenous Grb2 protein inside the cytosol of SK-BR-3 human breast cancer cells with pronounced inhibitory effect on cell mobility and viability. This work showcases a rational design of Grb2-targeted site-specific covalent inhibitor and its pronounced anticancer effect by targeting Grb2-Sos1 interaction.
authors.affiliation: Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine , Shanghai, China.|Department of Chemistry, The Chinese University of Hong Kong , Shatin, Hong Kong SAR, China.
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Shatin, Hong Kong SAR, China.
authors.forename: Yunyu
authors.initials: Y
authors.lastname: Nie
authors.affiliation: Department of Biomedical Engineering, The Chinese University of Hong Kong , Shatin, Hong Kong SAR, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Feng
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Shatin, Hong Kong SAR, China.
authors.forename: Jiale
authors.initials: J
authors.lastname: Qu
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Shatin, Hong Kong SAR, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, The Chinese University of Hong Kong , Shatin, Hong Kong SAR, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Bian
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong , Shatin, Hong Kong SAR, China.
authors.forename: Jiang
authors.identifier: 0000-0001-8112-7625
authors.initials: J
authors.lastname: Xia
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism*; D019556:COS Cells; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002522:Chlorocebus aethiops; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005434:Flow Cytometry; D051380:GRB2 Adaptor Protein / Q000378:metabolism*; D006801:Humans; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D020837:SOS1 Protein / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D051380:GRB2 Adaptor Protein; D010455:Peptides; D020837:SOS1 Protein; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: Grb2−Sos1 interaction; Ras signaling pathway; SH3 domain; breast cancer; nucleophilic reaction; targeted covalent inhibitor