Enhancing anti-tumor immunity through TIGIT blockade and tumor-directed targeting in pancreatic cancer

Résumé fourni par la source

Pancreatic ductal adenocarcinoma (PDAC) exhibits profound resistance to immune checkpoint blockade, driven by a dense stroma, low immunogenicity, and an immunosuppressive tumor microenvironment. T cell immunoreceptor with Ig and ITIM domain (TIGIT) is an inhibitory receptor expressed on tumor-infiltrating lymphocytes and contributes to immune dysfunction in PDAC through its interaction with PVR. To selectively modulate the TIGIT axis within the tumor microenvironment, we developed a bispecific antibody (chi2B5×4F11) that targets TIGIT while anchoring to CUB domain-containing protein 1 (CDCP1), thereby enabling spatially confined immune activation in CDCP1-positive tumor niches. Functional characterization using in vitro NK-92 cell assays and in vivo studies using a humanized mouse model engrafted with CDCP1 + PANC-1 cells demonstrated the efficacy of these antibodies. Parental chi4F11 effectively blocked the TIGIT–PVR axis, restoring AKT-FOXO1 signaling without altering CD226 expression. Chi2B5×4F11 further enhanced NK-92 cell-mediated cytotoxicity and induced the release of pro-inflammatory cytokines in vitro . In vivo, treatment with chi2B5×4F11 reduced the proportion of TIGIT + circulating immune subsets within the CD226 + compartment, suggesting functional restoration of co-stimulatory signaling. These findings highlight TIGIT as a crucial therapeutic target and suggest a strategy to overcome the immune resistance of pancreatic cancer. • High-affinity anti-CDCP1×TIGIT bispecific antibody, chi2B5×4F11, via IgG1κ-scFv format. • chi2B5×4F11 enhances NK-92 cell-mediated cytotoxicity in pancreatic cancer. • chi2B5×4F11 suppresses tumor growth in a humanized pancreatic cancer model. • TIGIT blockades reduce the proportion of circulating TIGIT + T cells and NK cells.

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