Abstract
Tumor-targeted T-cell therapies of various types have been booming, but T-cell therapy is limited by its inability to penetrate the collagen barrier surrounding tumors. The destruction of tumor collagen is significant because collagen both suppresses T cells and contributes to the formation of the extracellular matrix. Our previously reported cell surface vimentin (CSV)-targeted and membrane-anchored IL12-armed (attIL12) T cells can reduce collagen production by killing cancer-associated fibroblasts, thereby increasing T-cell infiltration. However, attIL12-T cells cannot reduce collagen expression by tumors that highly express CCKAR. In this study, we discovered that CCKAR directly boosts collagen production by tumor cells in vitro and in vivo. attIL12-modified tumor-infiltrating lymphocytes (TILs) disabled collagen production by CCKAR-high autologous tumor cells in vitro and sarcoma patient-derived xenografts (PDXs) in vivo. This disruption of collagen production by tumor cells required a simultaneous interaction between the CSV on autologous tumor cells, which is targeted by attIL12, and HLA-TCR on attIL12-TILs; when either interaction was abrogated, collagen production and CCKAR expression were not shut down. Mechanistically, the interaction between attIL12-TILs and autologous tumor cells synergized IFNγ production, which in combination with CCKAR downregulation reduced collagen expression through suppression of both TGFβ-stimulated SMAD activation and CCKAR-AKT signaling. Diminishing collagen expression from tumor cells significantly increased T-cell infiltration and improved tumor growth inhibition in PDX sarcomas. This study thus uncovers the first tumor collagen-disrupting T-cell therapy we know of. This is significant because collagen is enriched in most high-grade CCKAR+ human sarcomas. Thus, this attIL12-TIL therapy holds great clinical potential for boosting T-cell infiltration in high-grade, collagen-rich tumors.