PD-L1 Activity Is Associated with Partial EMT and Metabolic Reprogramming in Carcinomas

Area of Science:

• Oncology
• Cancer Biology
• Immunology

Background:

• Immune evasion and metabolic reprogramming are key cancer hallmarks linked to poor prognosis and treatment resistance.
• The interplay between immunosuppression and altered energy metabolism shapes the tumor microenvironment, promoting cancer aggressiveness.
• A comprehensive pan-cancer analysis linking these hallmarks with epithelial-mesenchymal transition (EMT) was lacking.

Approach:

• A meta-analysis of 184 transcriptomic datasets and The Cancer Genome Atlas (TCGA) data was performed.
• Investigated the association between immune checkpoint markers (e.g., PD-L1) and metabolic signatures (glycolysis, OXPHOS) in relation to EMT.
• Validated findings using single-cell RNA-seq and time-course EMT induction data.

Key Points:

• Enhanced PD-L1 activity signatures positively correlate with partial EMT and elevated glycolysis, but reduced oxidative phosphorylation (OXPHOS) across numerous carcinomas.
• These trends were consistently observed in both large-scale transcriptomic data and cell line experiments.
• Concurrent enrichment of glycolysis and PD-L1 activity is associated with significantly worse overall survival compared to PD-L1 enrichment alone.

Conclusions:

• Epithelial-mesenchymal transition (EMT) acts as a common driver linking immune evasion (PD-L1) and metabolic reprogramming (glycolysis).
• Functional synergy between PD-L1 activity and glycolysis promotes cancer metastasis and multi-drug resistance.
• Targeting these interconnected pathways may offer novel therapeutic strategies for advanced cancers.