YBX1&YBX3 as novel targets to potentiate immune checkpoint blockade response in gliomas

Area of Science:

• Immunology
• Oncology
• Molecular Biology

Background:

• Glioblastoma (GBM) displays significant resistance to CD8+ T cell-mediated killing, with tumor-intrinsic mechanisms of immune evasion poorly understood.
• Previous research identified Checkpoint Kinase 2 (Chek2) as a key factor in GBM's CD8+ T cell resistance.
• This study focuses on the immunomodulatory program driven by the regulatory hub involving CHK2, Y-box-binding protein 1 (YBX1), and Y-box-binding protein 3 (YBX3).

Purpose of the Study:

• To investigate the role of the CHK2-YBX1&YBX3 regulatory hub in glioblastoma's immune evasion.
• To explore the therapeutic potential of targeting this hub to enhance anti-tumor immunity and improve treatment outcomes.

Main Methods:

• Utilized immunoprecipitation followed by mass spectrometry and phosphoproteomics to study protein interactions.
• Generated single gene knockouts of CHEK2, YBX1, and YBX3 in human and mouse glioma cells.
• Performed transcriptomic, epigenetic, single-cell RNA sequencing, and spatial transcriptomics analyses. Conducted in vivo survival studies.

Main Results:

• CHK2, YBX1, and YBX3 demonstrated reciprocal positive regulation; depletion of any component led to increased pro-inflammatory gene expression.
• Pharmacological inhibition of YBX1 induced degradation of the CHK2-YBX1&YBX3 hub, enhancing antigen presentation and CD8+ T cell proliferation.
• Combination therapy targeting the CHK2-YBX1&YBX3 hub with immune checkpoint blockade (ICB) significantly improved survival in preclinical glioma models.

Conclusions:

• Identified a novel glioma-intrinsic immunosuppressive program regulated by the CHK2-YBX1&YBX3 hub.
• Proposes targeting the CHK2-YBX1&YBX3 hub as a strategy to potentiate responses to immune checkpoint blockade in glioma therapy.