Abstract B026: αvβ5 Integrin serves as a tumor-specific marker for immunosuppressive regulatory T cells in pancreatic cancer

Abstract

Abstract Regulatory T cells (Tregs) contribute to the immunosuppressive nature of pancreatic ductal adenocarcinoma (PDAC). Systemic depletion of Tregs can enhance anti-tumor T cell immunity, but can also cause unwanted autoimmune complications. A tumor-specific Treg-targeted therapy that effectively and safely enhances anti-tumor immunity for PDAC treatment remains an unmet need. We have recently found that αvβ5 integrin is expressed on Tregs that reside in the PDAC, but not those in the spleen, suggesting that the integrin can serve as a targetable marker for tumor-resident Tregs. Indeed, long-term treatment with the iRGD tumor-penetrating peptide, which effectively targets αvβ5+ cells in PDAC tissue, depleted Tregs in a tumor-specific manner leading to a significant expansion of CD8+ T cells in transgenic and syngeneic PDAC mouse models. αvβ5+ Tregs were induced from both naïve CD4+ T cells and naturally occurring Tregs. T cell receptor stimulation was found to be the common inducer of αvβ5+ Tregs. αvβ5+ Tregs formed a subpopulation of CCR8+ Tregs, which are preferentially found in the tumor tissue of various cancer types. Our most recent data show that the αvβ5 integrin marks a highly immunosuppressive fraction of the CCR8+ Tregs, suggesting that targeting αvβ5+ Tregs can lead to effective depletion of immunosuppressive Tregs in a tumor-specific manner. Citation Format: Yuki Kunisada, Kodai Suzuki, Norio Miyamura, Shingo Eikawa, Tatiana Hurtado de Mendoza, Evangeline S. Mose, Caisheng Lu, Yukihito Kuroda, Erkki Ruoslahti, Andrew M. Lowy, Kazuki N. Sugahara. αvβ5 Integrin serves as a tumor-specific marker for immunosuppressive regulatory T cells in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B026.