Abstract 1216: Novel strategies in cancer immunotherapy: Harness the hERG1 β1 macromolecular complex via a new bispecific antibody and its bifunctional TRAIL

Abstract

Introduction Among hindrances in cancer treatment, the lack of appropriate markers to be exploited for targeted therapy, and the need of new potential drugs are two big challenges.hERG1 potassium channels are a novel class of oncological targets and, in cancer, they are known to interact with integrins. It has been recently demonstrated that macromolecular complexes formed between hERG1 and β1 integrins selectively occurs in many types of cancer (Becchetti A et al., 2017). In this scenario, hERG1 could be exploited as a therapeutic target providing non cardiotoxic strategies aimed at blocking hERG1. Materials and Methods A scDb, a bifunctional single-chain diabody, directed against hERG1/β1 complex, was developed via SOE-PCR methodology. Such antibody was tested on HCT116 cells in lateral motility and western blotting experiments. Moreover immunohistochemistry (IHC) was performed on metastatic colorectal cancer (mCRC) paraffin embedded samples using the scDb, an anti-hERG1 and an anti-β1 integrin. Moreover, we improved the pro-apoptotic effects of the nude hERG1/β1-scDb, developing a trifunctional recombinant protein, in which the scDb-hERG1-β1 was linked to the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). Results and Discussion Performing IHC on sequential sections of mCRC confirmed the specificity of the scDb for both hERG1 and β1 integrin. In vitro data provide evidences that the administering of the bispecific antibody has an impact on lateral motility. Moreover, signaling pathways are also affected by the antibody treatment, as AKT phosphorylation and HIF1α levels are decreased when the molecule is administered, suggesting a possible effect of the bispecific antibody on the VEGF-A signaling pathway, which are consistent with our previous hypothesis (Becchetti A et al., 2017) of a possible cross-talk leading to a deep impact on VEGF expression and, thus, on neoangiogenesis. Encouraging results were obtained when testing the scDb-hERG1-β1 -TRAIL fusion protein, which was capable to produce a strong induction of apoptosis in ALL cells (32.6 vs 11% at 24h; 62.4% vs 10% at 48h), with no effects on TRAIL- resistant (Panc1) tumour cells. Conclusions scDb-hERG1/β1 could be used as a potential new therapeutic tool for cancer patients’ treatment as well as for early molecular diagnosis. In fact, the selective expression of hERG1/β1 complex in cancer cells and its role in angiogenesis and cancer progression suggests that a molecule selectively targeting the complex will be an invaluable tool for cancer treatment. In this view, we have recently licensed a patent which will be exploited with the final aim to undergo clinical trials. Becchetti A, et al. (2017) Science Signaling 10(473). Patent. Inventors: Arcangeli A, Duranti C. et al. Patent Ref: 102017000083637 Citation Format: Claudia Duranti, Jessica Iorio, Stefano Coppola, Giulia Petroni, Tiziano Lottini, Lara Magni, Elena Lastraioli, Annarosa Arcangeli. Novel strategies in cancer immunotherapy: Harness the hERG1 β1 macromolecular complex via a new bispecific antibody and its bifunctional TRAIL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1216.