PO-268 The interaction of hERG1 potassium channels with integrin receptors perturbs the force transduction machinery in pancreatic cancer

Abstract

IntroductionIon channels regulate cell proliferation, differentiation, and migration through cell-cell and cell–extracellular matrix interactions mediated by integrins. K+ flux through the human ether-à-gogo–related gene 1 (hERG1) channel shapes action potential firing in excitable cells, e.g. cardiomyocytes. Its abundance is often aberrantly high in human tumours, including the pancreatic ductal adenocarcinoma (PDAC). We recently demonstrated that the direct interaction of β1 integrins with hERG1 channels in cancer cells stimulated distinct signalling pathways that depended on the conformational state of hERG1 and affected different aspects of tumour progression.1 We hypothesised that hERG1 channels compromise the PDAC mechano-reciprocity, the ability to dynamically respond to externally applied forces by exerting forces, which enhances invasion and compromises treatment.Material and methodsUsing elastic micropillar arrays of varying stiffness,2 we quantified the β1-integrin mediated forces exerted by PANC-1 cells. Micropillars coating with collagen and/or fibronectin derived peptides allowed us to direct cell surface receptor binding specificity (i.e. α2β1 and α5β1 integrins).Results and discussionsIndependently of the substrate coating, PANC-1 cells exerted higher forces as a function of substrate stiffness, as already demonstrated for other cell types. Remarkably, the disruption of the β1/hERG1 interaction through E4031 inhibition of hERG1 channels resulted in a significant increase in the detected cellular forces. Our results suggest that in addition to alter distinct signalling pathways1 the direct interaction of β1 integrins and hERG1 channels perturbs the force transduction machinery.ConclusionThese findings encouraged us to develop bispecific antibodies (scDb, single-chain diabody) binding to the β1/hERG1 complex that are now being validated in PDAC cell lines. In particular, we have developed a bispecific antibody (scDb-β1/hERG1),3 which is composed by the variable domains (VH and VL chains) of monoclonal antibodies binding two different antigens, hERG1 and β1 integrin.ReferencesBecchetti, et al. Science Signaling2017;10, eaaf3236.van Hoorn, et al. Nano Lett2014;14:4257.A. Arcangeli, C. Duranti, S. Crescioli, L. Carraresi. Patent Ref: 102017000083637 (University of Florence).