BPTF Depletion Enhances T-cell-Mediated Antitumor Immunity

Area of Science:

• Immunology
• Cancer Research
• Chromatin Biology

Background:

• The nucleosome remodeling factor (NURF) complex, implicated in fruit fly immunity, has not been studied in mammalian systems.
• Understanding NURF's role in mammalian immunity is crucial for developing novel cancer therapies.

Purpose of the Study:

• To investigate the role of NURF in mammalian antitumor immunity.
• To determine if targeting NURF can enhance the immune response against cancer.

Main Methods:

• NURF was disabled in mice by silencing its essential subunit, bromodomain PHD-finger containing transcription factor (BPTF).
• Antitumor immunity was assessed in syngeneic cancer models using CD8+ and CD4+ T cell analysis.
• Mechanistic studies involved examining gene expression of immunoproteasome and antigen transporter components, and using a PSMB8 inhibitor.

Main Results:

• Disabling BPTF significantly enhanced antitumor immunity in mice.
• Elevated numbers of activated CD8+ T cells and enhanced cytolytic activity were observed in BPTF-deficient tumors, suggesting novel antigen involvement.
• NURF was found to directly regulate genes involved in antigen processing (Psmb8, Psmb9, Tap1, Tap2), and inhibition of PSMB8 reversed the enhanced immunity.

Conclusions:

• NURF normally suppresses tumor antigenicity; its depletion enhances antigen processing and CD8 T-cell cytotoxicity.
• Targeting NURF improves antitumor immunity, identifying it as a potential therapeutic target for cancer immunotherapy.
• The immunoproteasome plays a critical role in the enhanced antitumor immunity observed upon NURF ablation.