UBE2D4 Upregulation Promotes Cuproptosis Sensitivity in Colorectal Cancer.

BACKGROUND: Cuproptosis, a copper-dependent form of regulated cell death, represents a potential therapeutic vulnerability in colorectal cancer (CRC). However, the regulatory mechanisms governing cuproptosis in CRC remain largely unknown. METHODS: UBE2D4 expression was analyzed in the TCGA-COAD cohort and validated in CRC cell lines (HCT116, HT29) and normal colon epithelial cells (FHC) by qRT-PCR and western blot. Paired CRC and adjacent normal tissues (n = 5) were also examined by western blot. UBE2D4-knockdown HT29 cells were generated by transient siRNA transfection to assess cell viability (CCK-8), migration (wound healing assay), and expression of cuproptosis-related genes (DLAT, HSP70, LIAS) under copper overload conditions (elesclomol+CuSO4). RESULTS: UBE2D4 was significantly upregulated in CRC tissues and cell lines compared to normal controls. In paired clinical samples, western blot confirmed that UBE2D4 protein expression was elevated in tumor tissues, accompanied by increased DLAT, HSP70 and LIAS. Copper overload induced typical cuproptotic mitochondrial morphology and triggered a marked upregulation of UBE2D4, DLAT, and HSP70, alongside downregulation of LIAS. UBE2D4 silencing had no effect on baseline cell viability or migration but significantly rescued cells from copper-induced cytotoxicity. Genetically, UBE2D4 knockdown specifically attenuated the copper-induced elevation of DLAT, while restoring HSP70 and LIAS to near-baseline levels. CONCLUSION: These findings identify UBE2D4 as a genetically upregulated and functionally significant gene in colorectal cancer. Its upregulation correlates with altered expression of cuproptosis-related genes, particularly DLAT, suggesting that UBE2D4 expression status may represent a genetic determinant of cuproptosis sensitivity in CRC. This study provides a genetic basis for stratifying CRC patients who might benefit from copper-based therapeutic strategies.