Tenascin C in pancreatic cancer-associated fibroblasts enhances epithelial mesenchymal transition and is associated with resistance to immune checkpoint inhibitor.

Tenascin C (TNC) is an extracellular matrix glycoprotein that is highly expressed in cancer stroma and is associated with tumor progression in pancreatic adenocarcinoma (PAAD). In this study, we aimed to investigate the potential involvement of TNC in the response to immune checkpoint inhibitors (ICI) among PAAD patients. Transcriptomic profiles were obtained from public databases and analyzed to compare TNC mRNA levels between tumor and normal tissues. Bioinformatic programs were used to predict paracrine communications between cancer cells and cancer-associated fibroblasts (CAFs), and the Tumor Immune Dysfunction and Exclusion (TIDE) score was calculated to predict response to ICI treatment in PAAD patients. An independent immunotherapeutic cohort was used to validate the clinical impact of the signatures. Results showed that TNC mRNA levels were significantly upregulated in tumors compared to normal tissues in PAAD, and patients with high TNC expression had significantly shorter overall survival than those with low TNC expression (P = 0.0125). TNC was predominantly expressed in CAFs of PAAD patients and was found to potentially enhance the epithelial-mesenchymal transition (EMT) of cancer cells via integrin receptors, contributing to resistance to ICI treatment. Patients with high TNC expression and high ITGαV or ITGB3 expression were associated with poor response to ICI therapy. In conclusion, these findings suggest that TNC -high CAFs play a crucial role in tumor progression and resistance to ICI therapy in PAAD patients, and targeting TNC and its interactions with cancer cells may provide a potential strategy for improving the efficacy of ICI therapy in PAAD.