101. Single CAR-T cell treatment controls disseminated ovarian cancer in a syngeneic mouse model.
- Author
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Ranoa DRE, Sharma P, Schane CP, Lewis AN, Valdez E, Marada VVVR, Hager MV, Montgomery W, Wolf SP, Schreiber K, Schreiber H, Bailey K, Fan TM, Hergenrother PJ, Roy EJ, and Kranz DM
- Subjects
- Humans, Female, Mice, Animals, T-Lymphocytes, Immunotherapy, Adoptive methods, Xenograft Model Antitumor Assays, Mice, Inbred C57BL, Cytokines metabolism, Tumor Microenvironment, Receptors, Chimeric Antigen genetics, Receptors, Chimeric Antigen metabolism, Ovarian Neoplasms
- Abstract
Background: Treatment of some blood cancers with T cells that express a chimeric antigen receptor (CAR) against CD19 have shown remarkable results. In contrast, CAR-T cell efficacy against solid tumors has been difficult to achieve., Methods: To examine the potential of CAR-T cell treatments against ovarian cancers, we used the mouse ovarian cancer cell line ID8 in an intraperitoneal model that exhibits disseminated solid tumors in female C57BL/6J mice. The CAR contained a single-chain Fv from antibody 237 which recognizes a Tn-glycopeptide-antigen expressed by ID8 due to aberrant O-linked glycosylation in the absence of the transferase-dependent chaperone Cosmc . The efficacy of four Tn-dependent CARs with varying affinity to Tn antigen, and each containing CD28/CD3ζ cytoplasmic domains, were compared in vitro and in vivo in this study., Results: In line with many observations about the impact of aberrant O-linked glycosylation, the ID8 Cosmc knock-out (ID8 Cosmc -KO) exhibited more rapid tumor progression compared with wild-type ID8. Despite the enhanced tumor growth in vivo, 237 CAR and a mutant with 30-fold higher affinity, but not CARs with lower affinity, controlled advanced ID8 Cosmc -KO tumors. Tumor regression could be achieved with a single intravenous dose of the CARs, but intraperitoneal administration was even more effective. The CAR-T cells persisted over a period of months, allowing CAR-treated mice to delay tumor growth in a re-challenge setting. The most effective CARs exhibited the highest affinity for antigen. Antitumor effects observed in vivo were associated with increased numbers of T cells and macrophages, and higher levels of cleaved caspase-3, in the tumor microenvironment. Notably, the least therapeutically effective CAR mediated tonic signaling leading to antigen-independent cytokine expression and it had higher levels of the immunosuppressive cytokine interleukin10., Conclusion: The findings support the development of affinity-optimized CAR-T cells as a potential treatment for established ovarian cancer, with the most effective CARs mediating a distinct pattern of inflammatory cytokine release in vitro. Importantly, the most potent Tn-dependent CAR-T cells showed no evidence of toxicity in tumor-bearing mice in a syngeneic, immunocompetent system., Competing Interests: Competing interests: DMK is a member of the scientific advisory board of Affini-T Therapeutics and a consultant for Tempus. PS, HS, KS, and DMK are co-inventors on a patent application related to these chimeric antigen receptors. No potential conflicts of interest were disclosed by the other authors., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2023
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