Abstract A028: Subclonal lineage recording in glioblastoma using CRISPR base editing

Abstract

Abstract Novel lineage tracing approaches are needed to undercover lineage relationships between diverse cells in complex tumors such as glioblastoma (GBM). Intratumoral heterogeneity in GBM drives treatment resistance and recurrence. This intratumoral heterogeneity is reflected by multiple cellular states seen within tumors and across patients. Unfortunately, little is known about their lineage relationships and shared origins. Here we’ve developed a novel lineage tracing technology to track the clonal and subclonal evolution in patient-derived GBM models. Our adenine base editor lineage tracing (ABELT) system uses a Cas9 adenine base editor (ABE) to induce heritable single-nucleotide changes in the 3’ untranslated region of endogenous transcripts. These heritable marks distinguish individual clonal populations and can be used to trace the relationship between progeny within each clone. We demonstrate our system's in vitro lineage tracing capacity and show that the ABELT system faithfully records lineage, which is recoverable with unmodified single-cell RNA sequencing approaches. We then track the relationships between evolving cellular states across multiple divisions in an evolving GBM model. Our ABELT technology enables the rapid engineering and lineage tracing of cancer models incompatible with previous approaches. This novel approach will enable our group and others to explore GBM intratumoral heterogeneity with subclonal resolution to determine transcriptional plasticity that ultimately leads to treatment resistance. Citation Format: Abigail C. Marshall, Aaron McKenna. Subclonal lineage recording in glioblastoma using CRISPR base editing [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr A028.