PEGylated SOCS3 Mimetics Encapsulated into PLGA-NPs as Selective Inhibitors of JAK/STAT Pathway in TNBC Cells

Sara La Manna,1 Alessia Cugudda,1 Flavia Anna Mercurio,2 Marilisa Leone,2 Sara Fortuna,3 Concetta Di Natale,4 Elena Lagreca,4 Paolo Antonio Netti,4 Valeria Panzetta,4 Daniela Marasco1 1Department of Pharmacy, CIRPEB: Research Center on Bioactive Peptides- University of Naples Federico II, Naples, 80131, Italy; 2Institute of Biostructures and Bioimaging (CNR), Naples, 80131, Italy; 3Italian Institute of Technology (IIT), Genova, 16152, Italy; 4Department of Ingegneria Chimica del Materiali e della Produzione Industriale (DICMAPI), University of Naples Federico II, Naples, 80125, ItalyCorrespondence: Daniela Marasco, Email daniela.marasco@unina.itIntroduction: SOCS3 (suppressor of cytokine signaling 3) protein is a crucial regulator of cytokine-induced inflammation, and its administration has been shown to have therapeutic effects. Recently, we designed a chimeric proteomimetic of SOCS3, mimicking the interfacing regions of a ternary complex composed of SOCS3, JAK2 (Janus kinase 2) and gp130 (glycoprotein 130) proteins. The derived chimeric peptide, KIRCONG chim, demonstrated limited mimetic function owing to its poor water solubility.Methods: We report investigations concerning a PEGylated variant of KIRCONG mimetic, named KIRCONG chim, bearing a PEG (Polyethylene glycol) moiety as a linker of noncontiguous SOCS3 regions. Its ability to bind to the catalytic domain of JAK2 was evaluated through MST (MicroScale Thermophoresis), as well as its stability in biological serum assays. The structural features of the cyclic compounds were investigated by CD (circular dichroism), nuclear magnetic resonance (NMR), and molecular dynamic (MD) studies. To evaluate the cellular effects, we employed a PLGA-nanoparticle as a delivery system after characterization using DLS and SEM techniques.Results: KIRCONG chim PEG-revealed selective penetration into triple-negative breast cancer (TNBC) MDA-MB-231 cells with respect to the human breast epithelial cell line (MCF10A), acting as a potent inhibitor of STAT3 phosphorylation.Discussion: Overall, the data indicated that miniaturization of the SOCS3 protein is a promising therapeutic approach for aberrant dysregulation of JAK/STAT during cancer progression.Keywords: SOCS3 protein, JAK/STAT pathway, mimetic chimeric peptides, nanoparticles