KEY POINTS
- The investigators combined radioresistant esophageal squamous cell carcinoma models, 3D spheroids, stem-cell enrichment, RNA sequencing, ChIP-seq, ATAC-seq, xenografts and patient tissue cohorts. Radioresistant KYSE150, KYSE30 and KYSE450 derivatives showed greater clonogenic survival, proliferation, spheroid formation and expression of CD44/CD133.
- Radiation increased nuclear NRF2 activity, while NRF2 overexpression enhanced post-radiation clonogenic survival and stem-like behavior. In KYSE150 xenografts treated with 8 Gy, hyperactive NRF2 reduced the antitumor effect of radiation; NRF2 depletion produced the opposite phenotype.
- Multi-omics analysis identified WNT5A as a direct NRF2 transcriptional target. NRF2 binding sites overlapped open chromatin around WNT5A; NRF2 knockdown markedly reduced binding peaks, while radiation enhanced them, both with p<0.0001 in genome-wide analyses.
- Mechanistically, NRF2-induced WNT5A increased phosphorylation of GSK-3β at Ser9, reducing GSK-3β activity and enabling β-catenin nuclear accumulation. WNT5A depletion reversed NRF2-driven sphere formation, proliferation, clonogenic survival and enhanced DNA-damage repair, while WNT5A re-expression restored these phenotypes.
- Pharmacological inhibition of NRF2 with brusatol or ML385, and inhibition of WNT signaling with LGK974, produced radiosensitization in experimental models similar to genetic pathway suppression. These findings establish targetability in vitro but do not demonstrate clinical safety or efficacy.
- Clinical correlation used biopsies from 100 patients with ESCC treated with chemoradiotherapy, of whom 70% had stage III–IV disease and 75% received >54 Gy, plus an independent surgical cohort of 34 patients. WNT5A expression was higher in tumor than adjacent tissue and high expression was associated with worse progression-free and overall survival; larger multicenter cohorts are still required for validation.
CLINICAL TAKEAWAY
The NRF2-WNT5A-β-catenin axis provides a plausible mechanistic explanation for stem-cell persistence and radioresistance in esophageal squamous cell carcinoma and identifies potential radiosensitization targets. This remains hypothesis-generating translational work: neither WNT5A-guided treatment selection nor pathway inhibition is ready for clinical use.