Yun Bi

The efficacy of immunotherapy in unresectable/recurrent/metastatic head and neck squamous cell carcinoma (U/R/M HNSCC) remains suboptimal compared with primary untreated resectable HNSCC. The immunologic and stromal landscape during immunotherapy in U/R/M HNSCC is crucial for understanding drug resistance mechanisms. In this study, single-cell RNA sequencing was performed on 42 pre- and posttreatment samples from patients in our prospective trial (NCT05156970) who received immunochemotherapy. A subset of myofibroblasts expressing CD266 was identified as hampering the response to immunochemotherapy in patients with U/R/M HNSCC. This distinct subtype of cancer-associated fibroblasts (CAF) enhanced extracellular matrix (ECM) stiffness and cellular tension through a PIEZO1-mediated biomechanical mechanism, spatially segregated CD8+ T-cell infiltration to establish immune-excluded niches, and ultimately facilitated immune evasion. Mechanistically, PIEZO1 inhibition suppressed YAP activation and reduced FAK phosphorylation, thereby mitigating matrix remodeling effects driven by myofibroblastic CAF CD266. We also observed that PIEZO1 inhibition had a synergistic effect with PD-1 blockade in HNSCC in vivo. In summary, our findings reveal an immunosuppressive mechanism in which stromal cells regulate ECM stiffness, presenting a potential therapeutic target for U/R/M HNSCC.

Single-cell transcriptomic landscape of OSCC across 19 patients.

YAP nuclear localization in CAF regions and tumor area.

χ2 analysis comparing cell-type distributions across clinical groups.

TNFRSF12A expression in HNSCC tumor tissues, matched adjacent nonmalignant tissues, and normal human tissues using public datasets.

The efficacy of immunotherapy in unresectable/recurrent/metastatic head and neck squamous cell carcinoma (U/R/M HNSCC) remains suboptimal compared with primary untreated resectable HNSCC. The immunologic and stromal landscape during immunotherapy in U/R/M HNSCC is crucial for understanding drug resistance mechanisms. In this study, single-cell RNA sequencing was performed on 42 pre- and posttreatment samples from patients in our prospective trial (NCT05156970) who received immunochemotherapy. A subset of myofibroblasts expressing CD266 was identified as hampering the response to immunochemotherapy in patients with U/R/M HNSCC. This distinct subtype of cancer-associated fibroblasts (CAF) enhanced extracellular matrix (ECM) stiffness and cellular tension through a PIEZO1-mediated biomechanical mechanism, spatially segregated CD8+ T-cell infiltration to establish immune-excluded niches, and ultimately facilitated immune evasion. Mechanistically, PIEZO1 inhibition suppressed YAP activation and reduced FAK phosphorylation, thereby mitigating matrix remodeling effects driven by myofibroblastic CAF CD266. We also observed that PIEZO1 inhibition had a synergistic effect with PD-1 blockade in HNSCC in vivo. In summary, our findings reveal an immunosuppressive mechanism in which stromal cells regulate ECM stiffness, presenting a potential therapeutic target for U/R/M HNSCC.