Abstract 59: Triple negative breast cancer (TNBC) targeting CAR-T cell constructs with phage display-derived peptides
Authors: Khodary Muhammad G. , Yirsaw Alehegne W. , Elsobky Yumna A. , Gurung Reshma , Jaynes Jessie , Samuel Temesgen , Sandey Maninder , Bedi Deepa 
Published: March 2024

Abstract
Introduction: Triple Negative Breast Cancer (TNBC) poses treatment challenges due to the absence of effective targeted therapies. CAR-T cell therapy, successful in hematological cancers, is now being investigated for solid tumors. Finding new CAR-T targets is vital to overcome TNBC's therapeutic constraints.
Methods: In this study, a Biopanning phage display strategy employing a library of random peptides was utilized to identify potential targets for CAR-T cell therapy against TNBC. Through this approach, Heat Shock Protein 60 (HSP60) emerged as a promising candidate due to its binding affinity to the selected phage clones. Subsequent validation of HSP60 surface expression on TNBC cell lines in comparison to normal cells was conducted using flow cytometry. Concurrently, patient survival data were gathered and analyzed to evaluate the clinical significance of HSP60 expression in TNBC. The identified peptides demonstrating high specificity and affinity for HSP60 on the surface of TNBC cells were chosen for the development of a third-generation CAR-T model, incorporating various optimizations and innovations.
Results: The Biopanning strategy successfully identified HSP60 as a prominent target for CAR-T cell therapy in TNBC. Flow cytometry analysis confirmed significantly elevated surface expression of HSP60 on TNBC cell lines compared to their normal counterparts, substantiating its potential as an accessible antigen for targeted therapy. Patient survival analysis linked elevated HSP60 levels with poorer prognosis in TNBC, highlighting the protein's clinical relevance. Peptides showing high specificity and binding to TNBC's HSP60 were integrated into a meticulously engineered third-gen CAR-T cell model. This design aimed to boost the CAR-T's precision in targeting and eliminating HSP60-expressing TNBC cells. Iterative optimizations ensured the construct's accuracy, laying the groundwork for a potent, tailored TNBC immunotherapy.
Discussion: The discovery of HSP60 as a prime target for CAR-T cell therapy in TNBC is a pivotal advancement. Its distinct presence on TNBC cell surfaces, confirmed via flow cytometry, highlights its suitability for targeted immunotherapy. The correlation between elevated HSP60 levels and poorer prognosis in TNBC patients underscores its value as both a biomarker and a therapeutic focus. The peptides' exceptional specificity and strong binding to HSP60 validate their use in crafting a third-generation CAR-T cell model. Their integration and careful refinements in CAR-T design aim to optimize efficacy while reducing off-target effects, laying a robust foundation for tailored TNBC immunotherapy. Preclinical evaluations are imperative to thoroughly assess the safety and effectiveness of this innovative CAR-T approach.
Citation Format: Muhammad G. Khodary, Alehegne W. Yirsaw, Yumna A. Elsobky, Reshma Gurung, Jessie Jaynes, Temesgen Samuel, Maninder Sandey, Deepa Bedi. Triple negative breast cancer (TNBC) targeting CAR-T cell constructs with phage display-derived peptides [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 59.