EMC2 suppresses ferroptosis via regulating TFRC in nasopharyngeal carcinoma.

BACKGROUND

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy with poorly understood underlying molecular mechanisms. Ferroptosis, a form of programmed cell death, is not fully elucidated in NPC.

METHOD

We conducted quantitative proteomics to detect dysregulated proteins in NPC tissues. The levels of endoplasmic reticulum membrane protein complex 2 (EMC2) in NPC tissue microarrays were evaluated by immunohistochemistry, and the prognostic value of EMC2 was analyzed in NPC patients. The role of EMC2 in ferroptosis and carcinogenesis was determined through in vitro and in vivo experiments. Quantitative proteomics, protease inhibition, ubiquitin detection, and rescue experiments were performed to explore the mechanism of EMC2-regulated ferroptosis.

RESULTS

Significantly upregulated EMC2 was detected in NPC, and it was closely related to the characteristics of tumor progression. Elevated EMC2 was obviously correlated with poor survival in patients with NPC. EMC2 knockdown promoted ferroptosis, inhibiting cell viability, migration, and invasion, and enhancing the efficacy of cisplatin in NPC cells. Conversely, EMC2 overexpression contributed to ferroptosis repression, malignant progression, and reduced the efficacy of cisplatin. In addition, EMC2 knockdown suppressed xenograft tumor growth and enhanced ferroptosis in nude mice. Mechanistically, we identified transferrin receptor (TFRC) as a critical downstream protein. EMC2 interacted with TFRC and promoted its ubiquitin-proteasomal degradation. EMC2 regulated ferroptosis by mediating the level of TFRC.

CONCLUSIONS

EMC2 suppresses ferroptosis and promotes tumor progression, and the EMC2-TFRC axis is a novel ferroptosis regulatory pathway. EMC2 is a potentially biomarker and therapeutic target for NPC.