Abstract 1766: Triggering the resolution of inflammation with agonistic anti-ChemR23 antibody dampens inflammation-driven carcinogenesis
Authors: Gauttier Vanessa , Lavy Margot , Trilleaud Charlène , Biteau Kévin , Girault Isabelle , Belarif Lyssia , Teppaz Géraldine , Mary Caroline , Thépénier Virginie , Blanquart Christophe , Barillé-Nion Sophie , Poirier Nicolas 
Published: July 2021

Abstract
Chronic inflammation is associated with abnormal non-phlogistic clearance (efferocytosis) of apoptotic cells by macrophages and a defect of the resolution of inflammation pathways. The resolution of inflammation is an active immunological process mediated by specialized pro-resolving mediator (SPM) which target specific resolutive G-protein coupled receptors expressed by different immune cells and participate to the tissue homeostasis return after an injury. Defects in the clearance of (chemotherapy-induced) apoptotic tumor cell debris strengthens inflammation and has been associated with exacerbated tumor growth in several preclinical models. Proresolutive therapeutic approaches, such as using exogenous resolvin E1 (RvE1), the natural lipidic proresolutive ligand of the GPCR ChemR23, have been shown to dampen tumor-associated inflammation and to reduce tumor growth. Using single-cell RNA sequencing analysis, we found that ChemR23 is mainly expressed by tumor-associated macrophages in melanoma and lung cancers. Moreover, ChemR23 expression was barely expressed in non-inflamed tissues indicating a preferential expression on the inflamed or tumor site. We screened and identified an anti-ChemR23 mAb which induces RvE1-like Akt and ERK signaling in mouse and human macrophages and favors macrophage polarization towards a pro-resolutive phenotype. In vitro, the agonist antibody significantly increased the phagocytosis of apoptotic tumor primary mesothelioma cells by human tumor-polarized macrophages. In vivo, the agonist ChemR23 mAb accelerates the resolution of inflammation in an acute inflammatory model, as illustrated by a significant decrease of inflammatory macrophages and neutrophils infiltrates as compared to isotype control groups both in mice and non-human primate models. Similarly, ChemR23 triggering with the anti-ChemR23 mAb improved weight recovery, reduced diarrhea and decreased the development of colon neoplastic foci in a chronic colitis model coupled with the injection of a carcinogen agent. Furthermore, the administration of the anti-ChemR23 mAb as a monotherapy displayed some partial and complete antitumor responses in immunocompetent mouse models of subcutaneous colon carcinoma (MC38 and CT26) as well as orthotopic mesothelioma (AK7). Finally, using an orthotopic triple-negative breast cancer model (4T1), while we observed a limited impact on primary tumor growth, spontaneous metastasis development in the lung was significantly inhibited by the ChemR23 agonist mAb monotherapy. Our study reveals for the first time the therapeutic potential of triggering the proresolutive pathways using an anti-ChemR23 agonistic mAb to limit chronic inflammation in the tumor microenvironment and inhibit metastasis development.
Citation Format: Vanessa Gauttier, Margot Lavy, Charlène Trilleaud, Kévin Biteau, Isabelle Girault, Lyssia Belarif, Géraldine Teppaz, Caroline Mary, Virginie Thépénier, Christophe Blanquart, Sophie Barillé-Nion, Nicolas Poirier. Triggering the resolution of inflammation with agonistic anti-ChemR23 antibody dampens inflammation-driven carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1766.