Abstract 3757: Probing glioblastoma and its microenvironment at single cell resolution

Abstract

Abstract Single-cell sequencing (scSeq) is a powerful tool to investigate cancer genomics at single cell resolution. Multiple studies have recently illuminated intratumoral heterogeneity in glioblastoma, however, the majority focused on molecular complexity of tumor cells, without taking into account unexplored host cell types that contribute to the microenvironment around GBM tumor. To address the glioblastoma microenvironment composition and potential tumor-host interactions, we performed deep coverage (176k average reads per cell) scSeq of freshly resected primary GBM patient tissue without implementing any tumor cell enrichment strategies. scSeq libraries for 902 cells were prepared using 10X Gemcode platform and sequenced on Illumina NextSeq 500. This run was of high quality with 2,663 median genes per cell and low mitochondrial gene percentage (median < 5%). We used Cell Ranger analysis pipelines and Seurat packages to classify individual cells into 10 clusters and visualize them using t-SNE two-dimensional projections. We then identified the signature gene set for each cluster, relative to all other cells. Pathway analysis of each cluster signature along with known GBM microenvironment cell signatures revealed glioma tumor population along with surrounding microglia/marcophages, astrocytes, pericytes, oligodendrocytes, T cells and endothelial cells. Cell type markers identified by single cell transcriptomics were validated by IHC analysis. Microenvironmental composition and single cell signature will be confirmed through single nuclei sequencing of preserved (Frozen) tumor sample. Our results demonstrate the cellular diversity of brain tumor microenvironment and lay a foundation to further investigate the individual tumor and host cell transcriptomes that are influenced not only by their cell identity but also by their interaction with surrounding microenvironment. Citation Format: Sen Peng, Sanhita Rath, Saumya Bollam, Jenny Eschbacher, Shwetal Mehta, Nader Sanai, Michael Berens, Seungchan Kim, Harshil Dhruv. Probing glioblastoma and its microenvironment at single cell resolution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3757.