Fine-tuning BACH2 dosage balances stemness and effector function to enhance antitumor T cell therapy

Area of Science:

• Immunology
• Cell Biology
• Cancer Research

Background:

• Adoptive T cell therapies face challenges with poor persistence of transferred cells.
• Current strategies for enhancing persistence risk oncogenesis through constitutive hyperactivation.
• Quiescent stem-like/memory T cells, regulated by BACH2, are crucial for sustained physiological responses.

Purpose of the Study:

• To investigate the role of quantitative BACH2 dosage in regulating CD8+ T cell differentiation.
• To engineer synthetic T cell states with enhanced and persistent antitumor activity.
• To explore the mechanistic basis of BACH2-mediated T cell state regulation.

Main Methods:

• Quantitative control of BACH2 gene dosage in CD8+ T cells.
• Analysis of T cell differentiation along the stem-effector continuum.
• Assessment of T cell persistence and antitumor efficacy in vivo.
• Mechanistic studies involving transcription factor occupancy (Jun, AP-1).

Main Results:

• Low-dose BACH2 expression promotes T cell persistence without compromising effector function, enhancing anticancer efficacy.
• High-level BACH2 overexpression leads to quiescence, hindering tumor control.
• Quantitative control of BACH2 dosage fine-tunes T cell differentiation, creating persistent antitumor states.
• Mechanistically, low-dose BACH2 attenuates Jun binding to AP-1-dependent genes, balancing differentiation and effector function.

Conclusions:

• Quantitative control of gene expression, specifically BACH2 dosage, is critical for engineering persistent antitumor T cell states.
• Optimized deployment of quiescence factors like BACH2 and FOXO1 can significantly improve cell therapy outcomes.
• This approach offers a safer and more effective alternative to constitutive T cell hyperactivation in adoptive immunotherapy.