PD-L1 expression is mediated by microRNA processing, Wnt/β-catenin signaling, and chemotherapy in Wilms tumor

Area of Science:

• Oncology
• Immunology
• Genetics

Background:

• Immune checkpoint inhibitors are effective in adult cancers, but less so in pediatric cancers.
• Regulation of immune checkpoint proteins like PD-L1 is poorly understood in pediatric cancers.

Purpose of the Study:

• To investigate the regulation of PD-L1 in Wilms tumor, a common pediatric kidney cancer.
• To identify factors influencing PD-L1 expression in pediatric cancers for potential therapeutic strategies.

Main Methods:

• Analyzed PD-L1 expression in Wilms tumor specimens, including chemotherapy-exposed samples.
• Utilized childhood cancer cell lines to study the in vitro effects of chemotherapeutics on PD-L1.
• Investigated the correlation between mutations in CTNNB1 and DROSHA and PD-L1 levels.
• Examined the impact of Wnt/β-catenin signaling activation and DROSHA/DICER1 knockdown on PD-L1 expression.
• Assessed DICER1 alterations in adult cancers concerning immune gene expression and response to checkpoint inhibitors.

Main Results:

• PD-L1 was upregulated in distinct subsets of Wilms tumor, particularly in chemotherapy-exposed specimens.
• Chemotherapeutics increased PD-L1 expression in vitro in childhood cancer cell lines.
• Mutations in CTNNB1 and DROSHA correlated with higher PD-L1 levels.
• Wnt/β-catenin signaling activation and DROSHA/DICER1 knockdown increased PD-L1 in vitro.
• DICER1 alterations in adult cancers were linked to immune gene signatures and improved response to immune checkpoint inhibitors.

Conclusions:

• Clinical and biological factors regulating PD-L1 in Wilms tumor have been identified.
• Findings suggest potential precision therapy approaches for pediatric immuno-oncology.
• Understanding PD-L1 regulation in pediatric cancers is crucial for improving treatment efficacy.