TMIC-28. LONG NON-CODING RNA EXPRESSION DIFFERS BETWEEN GLIOBLASTOMA PATIENT IMMUNE CELLS AND HEALTHY VOLUNTEERS

Abstract To improve glioblastoma treatment, improved characterization of the tumor’s immune microenvironment is critical. Aberrant long non-coding RNA (LncRNA) expression has been implicated in the pathogenesis of many cancers, including glioblastoma. Other studies have discovered long non-coding RNAs which regulate immunity. However, lncRNA expression has not been systematically investigated glioblastoma patient immune cells. We aimed to investigate the differential expression of LncRNA and mRNs in the T lymphocytes and monocytes of glioblastoma patients when compared to healthy controls in an unbiased fashion. CD3 and CD14 cells were sorted from PBMC samples from 3 newly diagnosed glioblastoma patients and 3 normal donors, and RNA was extracted from them. These RNA samples were run on the Arraystar Human LncRNA microarray. We found 309 LncRNAs differentially expressed in glioblastoma patient T cells, and 316 in patient monocytes (fold change >2 or £0.5, P£0.05). A preliminary review of this data has revealed upregulation of lncRNAs that have previously been reported to play a role in tumorigenesis, such as MIF12-AS1, VIM-AS1, and WEE2-AS1. Additionally, lncRNAs such as CCDC26 and Hoxa10 that have been implicated in immune cell differentiation and hyperactivity also show differential expression between the two groups. We also found differential expression of 203 mRNA in T cells and 467 in monocytes (fold change ³2 or £0.5, P£0.05). An analysis based on the Kyoto Encyclopedia of Genes and Genomes identified 42 biological pathways that have enrichment of these differentially expressed mRNAs (P£0.05), including the RIG-I-like receptor pathway and toll-like receptor pathway, both implicated in innate immunity in T-cells. This array data will form the template for future single-cell RNA sequencing of tumor-infiltrating immune cells; peripheral immune cells from glioblastoma patients; and immune cells from non-tumorous brain (epilepsy tissue) and blood samples to investigate these differences in greater detail.