Multimodal C9-66 CAR-T cell immunotherapy improves outcome in preclinical models of pancreatic cancer.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal cancers due to its aggressive biology and resistance to existing therapies. Oncofetal chondroitin sulfate (ofCS) is a tumour-restricted glycosaminoglycan broadly expressed across solid cancers but largely absent from normal adult tissues. We developed C9-based chimeric antigen receptor (CAR)-T cells targeting ofCS to overcome poor antigen specificity and the immunosuppressive tumour microenvironment (TME). To optimise ofCS-targeted C9 CAR-T cell therapy for PDAC through integrated CAR design optimisation, metabolic enhancement and TME reprogramming. C9 and charge-optimised C9-66 CAR-T cells were engineered using a humanised ofCS-binding single-chain antibody fragment. Antitumour efficacy, functional durability and metabolic fitness were assessed in murine and patient-derived PDAC models. Enhancement strategies included inosine-mediated metabolic reprogramming, <i>Nr5a2</i> overexpression and sequential TME remodelling using GLP-1R modulation, CSF-1R blockade and programmed cell death protein-1 inhibition. C9 CAR-T cells exhibited potent cytotoxicity, delayed tumour progression and extended survival in PDAC models. Compared with the parental construct, charge-optimised C9-66 CAR-T cells showed reduced exhaustion and more sustained activity in vivo. Inosine enhanced cytokine production, promoted central-memory differentiation and mitigated exhaustion, whereas <i>Nr5a2</i> overexpression increased mitochondrial respiration and cytotoxicity. Sequential GLP-1R on-off modulation with macrophage and checkpoint blockade enhanced intratumoural CAR-T cell activity and prolonged survival. Human C9-66 CAR-T cells retained specific ofCS recognition and lysed patient-derived PDAC cells in vitro and in vivo. C9-66 CAR-T cells with metabolic optimisation and TME reprogramming represent a tumour-specific and clinically translatable immunotherapeutic strategy for PDAC and other ofCS-expressing solid tumours.