Dysregulated expression of the tumor suppressor p14ARF in cancer provides an effective target for TCR-T cell therapeutics.

BACKGROUND: The CDKN2A gene encodes two canonical tumor suppressors, p16INK4A and p14ARF, which safeguard cells from malignant transformation by inducing cell cycle arrest and apoptosis in response to aberrant growth signals. Paradoxically, many cancers overexpress these proteins when downstream effectors that enforce negative feedback regulation are lost or inactivated. For example, p14ARF, which regulates p53 activation, is aberrantly expressed in more than 50% of tumors with inactivating p53 mutations. Here, we evaluated the feasibility of targeting dysregulated p16INK4A and p14ARF expression using TCR-T cell therapeutics. METHODS: We analyzed a panel of p16INK4A- and p14ARF-derived peptides for HLA-A*02:01-associated presentation and recognition by CD8(+) T cells. Antigen-specific T cell receptors were isolated from healthy donor repertoires and expressed in primary T cells to assess specificity, functional avidity, tumor recognition, and safety using in vitro T cell functional assays, in vivo tumor models, and an in vivo safety model. RESULTS: We identified a unique and well-presented p14ARF epitope that was consistently detected in the HLA-A*02:01-associated immunopeptidome of cancer biopsies but not in normal tissues. High-avidity ARF-specific TCRs were isolated from the peripheral repertoire of healthy donors, and TCR-transduced T cells mediated potent tumor cell killing in vitro and in vivo in preclinical models. Furthermore, targeting p14ARF-expressing cells did not result in detectable on-target toxicity in an in vivo safety model. CONCLUSIONS: These findings demonstrate the feasibility of targeting dysregulated tumor suppressor proteins with TCR-T cell therapeutics and identify p14ARF as a promising target for future therapies.