Abstract 3422: Combined treatment with interleukin-4 receptor-targeted cytotoxic peptide and PD-L1-blocking peptide efficiently induces immunogenic cell death of tumor cells and activates T-cell activity

Abstract

Abstract Immune checkpoint blockade therapy has provided clinical benefit to some patients with advanced cancer including melanoma and non-small cell lung cancer. However, many patients still fail to respond to single immune checkpoint blockade therapy. The need for combination therapies to increase anti-tumor responses is becoming important. Interleukin-4 receptor (IL4R) is frequently overexpressed in various cancer types and promotes tumor cell survival. PD-L1, a well-known immune checkpoint, is up-regulated in malignant tumors and inhibits T-cell activity. In this study, we aimed at a combination therapy using an IL4R-targeted cytotoxic peptide and PD-L1-blocking peptide. To target IL4R-high tumor cells, we exploited IL4RPep-1-KLA composed of IL4RPep-1, an IL4R-binding peptide, and (KLAKLAK)2, a cytotoxic peptide. IL4RPep-1-KLA induced necrosis as well as apoptosis of IL4R-expressing tumor cells and increased the secretion of CRT, HMGB1, and ATP, well-known markers of immunogenic cell death (ICD). Flow cytometry analysis showed that the conditioned medium of tumor cells treated with IL4RPep-1-KLA enhanced the expression of CD86 and CD80 on dendritic cells, suggesting the activation and maturation of dendritic cells through ICD. Sequential treatment with IL4RPep-1-KLA followed by PD-L1Pep-2, a PD-L1-blocking peptide, during the co-culture of tumor cells and CD8+ T-cells activated T-cell activity including T-cell proliferation and cytokine secretion more efficiently than single treatment with IL4RPep-1-KLA or PD-L1Pep-2, or simultaneous treatment. These results suggest that sequential, combined treatment with the IL4R-targeted cytotoxic peptide and PD-L1-blocking peptide can induce ICD of tumor cells and maturation of dendritic cells and subsequently activate T-cells. This treatment is a promising strategy for cancer immunotherapy. Citation Format: Nawon Park, Byungheon Lee, Hyunsu Lee. Combined treatment with interleukin-4 receptor-targeted cytotoxic peptide and PD-L1-blocking peptide efficiently induces immunogenic cell death of tumor cells and activates T-cell activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3422.