Engraftment of a surrogate antigen onto tumor cell surface via pHLIP peptide to universally target CAR-T cell therapy to solid tumors

• Published in: Cancer letters 2025-01, Vol.608, p.217319, Article 217319
• Main Authors: Zhang, Yan-ting, Fu, Xinping, Ting Lim, Jane Jing, Zhang, Shaun Xiaoliu
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Monoclonal - immunology; Antibodies, Monoclonal - pharmacology; Antibody therapy; Antigens, Neoplasm - immunology; Cancer immunotherapy; CAR-T cells; Cell Line, Tumor; Female; Humans; Immunotherapy, Adoptive - methods; Killer Cells, Natural - immunology; Membrane Proteins; Mice; Neoplasms - immunology; Neoplasms - therapy; pHLIP peptide; Proto-Oncogene Proteins c-myc - genetics; Proto-Oncogene Proteins c-myc - immunology; Proto-Oncogene Proteins c-myc - metabolism; Receptors, Chimeric Antigen - immunology; Receptors, Chimeric Antigen - metabolism; Surrogate tumor antigen; T-Lymphocytes - immunology; T-Lymphocytes - metabolism; Targeting acidic tumor microenvironment; Tumor Microenvironment - immunology; Xenograft Model Antitumor Assays
• ISSN: 0304-3835; 1872-7980; 1872-7980
• DOI: 10.1016/j.canlet.2024.217319

CAR-T cells and monoclonal antibodies (mAbs) are immunotherapeutics that have shown efficacies against certain malignancies. However, their broad application is hindered by the scarcity of tumor-associated antigens on tumor cell surfaces. Previous investigations unveiled the unique capacity of pH-low insertion peptide (pHLIP) to anchor to plasma membranes under acidic conditions. Considering that an acidic tumor microenvironment is a hallmark of solid tumors, we engineered a novel peptide, Myc-pHLIP, by tethering a surrogate epitope tag, the c-Myc-tag, to pHLIP. We evaluated the efficiency of Myc-pHLIP in inserting the artificial c-Myc-tag onto the plasma membrane of malignant cells and determined if this engraftment could convert it into a therapeutic target for CAR-T cells or mAbs. Our in vitro experiments demonstrated that incubating Myc-pHLIP with tumor cells in acidic media triggered significant killing by either Myc-targeted CAR-T cells (Myc-CAR-T), or by an anti-Myc mAb in the presence of NK cells. In vivo studies demonstrated substantial antitumor effects with sequential administration of Myc-pHLIP followed by either Myc-CAR-T or Myc-mAb. These findings establish that Myc-pHLIP has the potential to act as a universal surrogate tumor antigen capable of directing CAR-T cells or mAbs to treat any solid tumors by concurrently targeting both malignant and stromal cells. •CAR-T cell and antibody therapy have shown efficacies against certain malignancies.•The paucity of suitable tumor-associated antigens hampers their clinical application.•A hallmark of solid tumors is the acidic tumor microenvironment.•Tethering a surrogate epitope, e.g., the c-Myc-tag, to pHLIP can overcome the lack of tumor antigen targets.•This c-Myc-Tag-pHLIP peptide allows tumor cells to be recognized and killed by both CAR-T and antibody therapy.