NRCAM variant defined by microexon skipping is a targetable cell surface proteoform in high-grade gliomas

  • bioRxiv. 2025 Aug 4:2025.01.09.631916. doi: 10.1101/2025.01.09.631916.
Priyanka Sehgal ,  Ammar S Naqvi ,  Makenna Higgins ,  Jiageng Liu ,  Kyra Harvey ,  Julien Jarroux ,  Taewoo Kim ,  Berk Mankaliye ,  Pamela Mishra ,  Grace Watterson ,  Justyn Fine ,  Jacinta Davis ,  Katharina E Hayer ,  Annette Castro ,  Adanna Mogbo ,  Charles Drummer ,  Daniel Martinez ,  Mateusz P Koptyra ,  Zhiwei Ang ,  Kai Wang ,  Alvin Farrel ,  Mathieu Quesnel-Vallieres ,  Yoseph Barash ,  Jamie B Spangler ,  Jo Lynne Rokita ,  Adam C Resnick ,  Hagen U Tilgner ,  Thomas De Raedt ,  Daniel J Powell ,  Andrei Thomas-Tikhonenko
PMID: 39868324 DOI: 10.1101/2025.01.09.631916
Abstract

To overcome the paucity of known tumor-specific surface Antigens in pediatric high-grade Glioma (pHGG), we contrasted splicing patterns in pHGGs and normal brain samples. Among alternative splicing events affecting extracellular protein domains, the most pervasive alteration was the skipping of ≤30 nucleotide-long exons. Several of these skipped microexons mapped to L1-IgCAM family members, such as NRCAM . Bulk and single-nuclei short- and long-read RNA-seq revealed uniform skipping of NRCAM microexons 5 and 19 in virtually every pHGG sample. Importantly, the Δex5Δex19 (but not the full-length) NRCAM proteoform was essential for pHGG cell migration and invasion in vitro and tumor growth in vivo. We developed a monoclonal antibody selective for Δex5Δex19 NRCAM and demonstrated that "painting" of pHGG cells with this antibody enables killing by T cells armed with an FcRI-based universal immune receptor. Thus, pHGG-specific NRCAM and possibly other L1-IgCAM proteoforms are promising and highly selective targets for adoptive immunotherapies.

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