Extracellular matrix–targeted TNC-scFv armoring enhances CAR T cell persistence and antitumor activity in solid tumors

Abstract

Chimeric antigen receptor T cell (CAR T cell) therapy has shown limited efficacy in solid tumors, largely due to physical and immunosuppressive barriers imposed by the tumor microenvironment (TME). Tenascin-C (TNC), an extracellular matrix protein highly expressed in multiple solid malignancies, contributes to immune exclusion and T cell dysfunction. Here, we engineer an armored CAR T cell platform that locally targets the extracellular matrix by secreting a TNC-specific single-chain variable fragment (TNC-scFv) linked to conventional CAR architecture. TNC-scFv–armored CAR T cells exhibit enhanced cytotoxic activity, improved persistence, and reduced exhaustion in vitro and in xenograft tumor models. Single-cell transcriptomic analysis reveals that TNC targeting reprograms the TME toward a CD8 + T cell–enriched and functionally active immune landscape. In humanized tumor models, TNC-scFv–armored CAR T cells mediate robust antitumor responses with minimal systemic toxicity. This extracellular matrix–targeted armoring framework is compatible with additional immunomodulatory payloads, as illustrated by combinatorial armoring with interleukin-2, which further enhances efficacy while mitigating cytokine-associated toxicity. Together, these results establish extracellular matrix–directed armoring as a generalizable strategy to improve CAR T cell therapy for solid tumors.