Nrf2 deficiency converts the ESCC microenvironment into an immunologically active state via the GPX2-ICD-DC signaling path.

BACKGROUND

Radiotherapy (RT) resistance remains a significant challenge in esophageal squamous cell carcinoma (ESCC). While Nrf2 is known to mediate antioxidant defense, its role in modulating the immunogenicity of radiotherapy-induced cell death is poorly understood.

METHODS

We established a spontaneous esophageal cancer model using genetically engineered mice with conditional knockout of Nrf2, and analyzed the tumor immune microenvironment by single-cell RNA sequencing. In vitro, we performed co-culture experiments using CRISPR/Cas9-mediated Nrf2-knockout esophageal cancer cell lines with dendritic cells and T cells to validate immune activation. In addition, in vivo validation was conducted using a mouse subcutaneous tumor model.

RESULTS

ScRNA-seq revealed that Nrf2 deficiency significantly remodeled the myeloid compartment, characterized by a population shift from Folr2 + to Mrc1 + macrophages and an expansion of effector T cells. Mechanistically, Nrf2 deletion downregulated the expression of Gpx2, impairing antioxidant defenses. This sensitized ESCC cells to RT, triggering the release of immunogenic cell death (ICD) markers, including ATP, HMGB1, and surface calreticulin (CRT). In tumor-DC-T cell co-culture systems, Nrf2-deficient cells stimulated dendritic cells (DCs) to secrete IP-10 (CXCL10), which was indispensable for the recruitment and activation of CD8 + T cells. Finally, in vivo experiments confirmed that Nrf2 deficiency enhanced radiosensitivity and promoted CD8 + T cell infiltration.

CONCLUSION

Our findings identify the Nrf2-Gpx2 axis as a master regulator of immunogenicity in ESCC. Targeting this axis represents a promising strategy to convert "cold" tumors into "hot" environments, thereby improving the efficacy of radiotherapy and immunotherapy.