Abstract 6633: Tracking cell-cell interactions using intercellular barcode transfer

Abstract Cell-cell interaction is one of the fundamental biological mechanisms by which cells communicate and is a key modality by which cancer cells interact with other cells in their microenvironment. Current methods, such as enzymatic labeling and proximity-based tagging, allow the experimental tracking of these interactions but are not compatible with sequencing-based readouts, which are essential for high-throughput analyses. We have developed a highly scalable intercellular barcode transfer technology that bridges this gap. Our novel “Relay” technology offers a scalable solution to monitor cell-cell interactions with unprecedented single-cell resolution, seamlessly integrating with existing high-throughput and sequencing platforms. Relay employs RNA barcodes to mark and track cell interaction events, providing definitive quantitative data on cell interaction partners. We used Relay to track interactions between cancer cells and T cells, capturing both potent antigen-specific engagements and subtler contacts involved in antigen sampling. Additionally, by integrating CRISPR libraries with Relay, we pioneered a novel approach for pooled CRISPR screens, focusing on intercellular interactions across different cell types. In this context, the cell harboring genetic perturbation may differ from the cell under analysis. To demonstrate this, we are conducting genome-wide perturbations in cancer cells and interrogating cancer cell factors that affect antigen sampling and trogocytosis by T cells and macrophages. Beyond its application in CRISPR screening, Relay can also be used with single-cell RNA sequencing to directly track and measure immune-cancer and immune-immune cell interactions at the single cell level. We applied single-cell Relay to a dendritic cell-T cell system to link dendritic cell signatures to T cell signatures based on direct cell contact and regulatory signaling. The design of Relay as a highly modular system extends its utility beyond cancer research, making it broadly applicable across various biological models and systems where cell-cell communication is a fundamental property in complex multicellular settings. This tool promises to accelerate the transition from theoretical understanding to practical exploration of cell-cell interactions, with profound implications for immunology, oncology, and beyond. Citation Format: Neil Q. Tay, Tiffany Juan, Joseph J. Muldoon, Justin Eyquem, Michael T. McManus. Tracking cell-cell interactions using intercellular barcode transfer [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 6633.