Enhancer of Zeste Homolog 2 Protects Mucosal Melanoma from Ferroptosis via the KLF14-SLC7A11 Signaling Pathway.

Background: Mucosal melanoma (MM) is epidemiologically, biologically, and molecularly distinct from cutaneous melanoma. Current treatment strategies have failed to significantly improve the prognosis for MM patients. This study aims to identify therapeutic targets and develop combination strategies by investigating the mechanisms underlying the tumorigenesis and progression of MM.

Methods: We analyzed the copy number amplification of enhancer of zeste homolog 2 (EZH2) in 547 melanoma patients and investigated its correlation with clinical prognosis. Utilizing cell lines, organoids, and patient-derived xenograft models, we assessed the impact of EZH2 on cell proliferation and sensitivity to ferroptosis. Further, we explored the mechanisms of ferroptosis resistance associated with EZH2 by conducting RNA sequencing and chromatin immunoprecipitation sequencing.

Results: EZH2 copy number amplification was closely associated with malignant phenotype and poor prognosis in MM patients. EZH2 was essential for MM cell proliferation in vitro and in vivo. Moreover, genetic perturbation of EZH2 rendered MM cells sensitized to ferroptosis. Combination treatment of EZH2 inhibitor with ferroptosis inducer significantly inhibited the growth of MM. Mechanistically, EZH2 inhibited the expression of Krüpple-Like factor 14 (KLF14), which binds to the promoter of solute carrier family 7 member 11 (SLC7A11) to repress its transcription. Loss of EZH2 therefore reduced the expression of SLC7A11, leading to reduced intracellular SLC7A11-dependent glutathione synthesis to promote ferroptosis.

Conclusion: Our findings not only establish EZH2 as a biomarker for MM prognosis but also highlight the EZH2-KLF14-SLC7A11 axis as a potential target for MM treatment.