Identification and validation of cuproptosis-related immune checkpoint expression for glioblastoma.

OBJECTIVE: Investigating the expression levels of immune checkpoint genes CD276, CD40, TNFSF14, and TNFSF9 in glioblastoma multiforme patients about copper death and patient prognosis. METHODS: Transcriptional data of GBM patients were obtained from the TCGA database. LASSO Cox regression analysis was performed to identify four immune checkpoint genes (CD276, CD40, TNFSF14, and TNFSF9) associated with copper death in glioblastoma. Bioinformatics analysis was conducted to explore the correlation between the key copper death protein FDX1 and immune checkpoints. The Kaplan-Meier analysis was conducted to assess the prognosis between groups with high and low expression levels. RESULTS: CD276, CD40, and TNFSF14 were significantly upregulated in glioblastoma compared to adjacent normal tissues (P < 0.05), while TNFSF9 was significantly downregulated (P < 0.05). Patients with high expression of CD276, CD40, and TNFSF14 showed significantly poorer prognosis compared to those with low expression (P < 0.05). There was no statistical difference in prognosis between high and low expression groups of TNFSF9 (P > 0.05). Knockdown of CD40, CD276, and TNFSF14 significantly reduced cell viability in the A172 cell line compared to the control group (P < 0.05), while overexpression of TNFSF9 significantly reduced cell viability (P < 0.05). Similar results were observed in the U251 cell line (P < 0.05) after knockdown of CD40, CD276, and TNFSF14, as well as overexpression of TNFSF9. CONCLUSION: The expression levels of immune checkpoint genes CD276, CD40, and TNFSF14 related to copper death are positively correlated with the prognosis of GBM patients, while the expression level of TNFSF9 is negatively correlated with the prognosis of GBM patients. This study establishes a novel link between immune checkpoint genes and cuproptosis, bridging copper-induced cell death mechanisms with immunotherapy for glioma.