Targeting of intracellular oncoproteins with peptide-centric CARs

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Most cancers are driven by intracellular proteins, limiting immunotherapies to mutated peptides (neoantigens).
• Neuroblastoma, a pediatric cancer, has few mutations and is driven by deregulated transcriptional networks.
• Current neoantigen-based therapies are insufficient for cancers with low mutational burdens.

Purpose of the Study:

• To develop novel immunotherapeutic strategies for neuroblastoma targeting intracellular oncoproteins.
• To investigate the potential of targeting the unmutated PHOX2B-derived peptide QYNPIRTTF in neuroblastoma.
• To engineer peptide-centric chimeric antigen receptors (PC-CARs) capable of recognizing specific tumor-associated peptides on multiple human leukocyte antigen (HLA) allotypes.

Main Methods:

• Identification of neuroblastoma-enriched peptides derived from tumorigenic proteins.
• Design and development of PC-CARs targeting the PHOX2B-derived peptide QYNPIRTTF.
• Utilizing counter-panning strategies and computational modeling to predict and validate cross-reactivity across different HLA allotypes.

Main Results:

• The neuroblastoma immunopeptidome is enriched with peptides from essential tumorigenesis proteins.
• PHOX2B-derived peptide QYNPIRTTF was identified on HLA-A*24:02 and targeted using PC-CARs.
• PHOX2B PC-CARs demonstrated recognition of QYNPIRTTF on HLA-A*23:01, broadening HLA allotype targeting.
• Demonstrated potent and specific killing of neuroblastoma cells in vitro and complete tumor regression in mice.

Conclusions:

• PC-CARs offer a promising approach to target intracellular oncoproteins previously inaccessible to immunotherapy.
• This strategy expands the potential immunotherapeutic targets beyond neoantigens for cancers with low mutational burden.
• PHOX2B PC-CARs show potential for broader clinical application by targeting additional HLA allotypes.