The EZH2-NEAT1 epigenetic axis promotes cuproptosis sensitivity and modulates cancer cell migration in colorectal cancer.

BACKGROUND

Cuproptosis represents a promising therapeutic strategy for colorectal cancer (CRC), yet the epigenetic mechanisms governing cuproptosis sensitivity remain largely unexplored. Enhancer of zeste homolog 2 (EZH2), a key epigenetic regulator frequently overexpressed in CRC, may play a critical role in modulating copper-induced cell death. This study aimed to investigate the role of EZH2 and its downstream effectors in regulating cuproptosis sensitivity in CRC cells.

METHODS

Using elesclomol-copper complex treatment, a cuproptosis model in HCT116 and RKO CRC cell lines was established. EZH2 expression changes during cuproptosis were examined, and functional studies were performed using EZH2 knockdown and overexpression approaches. The mechanistic link between EZH2 and the long non-coding RNA (lncRNA) NEAT1 was investigated by chromatin immunoprecipitation and transcriptional analysis. Rescue experiments were conducted to validate the EZH2-NEAT1 axis in cuproptosis regulation. Additionally, the effects of this pathway on CRC cell migration in macrophage co-culture systems were examined.

RESULTS

The elesclomol-copper treatment induced dose-dependent cell death characterized by HSP70 upregulation and dihydrolipoamide S-acetyltransferase (DLAT) protein aggregation. Both EZH2 and NEAT1 were significantly upregulated during copper-induced cell death. EZH2 knockdown protected cells from cuproptosis by reducing DLAT aggregation and proteotoxic stress, while EZH2 overexpression enhanced copper-induced death. Mechanistically, EZH2 transcriptionally activates NEAT1 by maintaining H3K27 acetylation at its promoter. Rescue experiments confirmed that NEAT1 overexpression restored cuproptosis sensitivity in the EZH2 knockdown cells, while NEAT1 depletion prevented EZH2-mediated death promotion. The EZH2-NEAT1 axis modulated lipoylated DLAT levels and proteotoxic stress without affecting FDX1 transcription. Further, this axis regulated the extracellular NEAT1 levels and influenced CRC cell migration in the macrophage co-culture systems, revealing effects beyond cell-autonomous death sensitivity.

CONCLUSIONS

The EZH2-NEAT1 axis functions as a pro-death pathway in cuproptosis execution machinery rather than a protective response. Tumors with elevated EZH2-NEAT1 expression may be particularly sensitive to copper-based therapies. This study establishes EZH2-NEAT1 expression as a potential biomarker for patient selection in cuproptosis-based cancer treatment, though the concurrent effects on tumor migration highlight complex therapeutic considerations for combination treatment strategies.