A T-cell receptor targeting RUNX1 frameshift mutations in acute myeloid leukemia.

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Runt-related transcription factor 1 (RUNX1) is crucial for hematopoietic differentiation.
• RUNX1 mutations, particularly frameshift mutations, are linked to poor prognosis in acute myeloid leukemia (AML).
• These frameshift mutations can lead to oncogenic proteins translated in an alternative reading frame.

Purpose of the Study:

• To investigate the potential of targeting the alternative reading frame of oncogenic RUNX1 via immunotherapy.
• To identify and validate neoantigens arising from RUNX1 frameshift mutations for therapeutic targeting.

Main Methods:

• Introduced RUNX1 frameshift mutations into B-cell lines and identified neopeptides using immunopeptidomics.
• Screened healthy individuals for RUNX1 neoantigen-specific CD8 T cells using peptide-MHC tetramers.
• Isolated and sequenced T-cell receptors (TCRs), then engineered CD8 T cells for functional assays and in vivo studies.

Main Results:

• Identified 13 neopeptides from RUNX1 frameshift mutations.
• Isolated T-cell clones recognizing 5 neoantigens across 4 HLA alleles.
• Demonstrated that TCR-engineered T cells effectively killed RUNX1-mutated AML cell lines, patient-derived AML cells, and leukemic stem cells in vitro and in immunodeficient mice.

Conclusions:

• RUNX1 frameshift mutations can be effectively targeted by immunotherapy.
• TCR-based immunotherapy holds significant potential for treating patients with RUNX1-mutated AML.
• The study validates the concept of targeting alternative reading frame neoantigens in AML treatment.