Abstract 1394: Role of non-coding RNA in regulation of stemness and differentiation via notch signaling pathway in glioblastoma

Abstract

Abstract Multiple distinct subpopulations of cancer cells within tumors may derive from a limited source of cancer cells, called cancer stem cells (CSCs), which may have plasticity and respond to signals from their microenvironment. Recent studies demonstrated the fundamental roles of long non-coding RNA (lncRNA) in various biological processes. Here, we investigated the roles of lncRNA in glioma stem cells (GSCs) differentiation. Whole-genome RNA sequencing revealed that 180 and 171 lncRNAs were commonly upregulated and downregulated with a greater than 2-fold difference in GSC differentiation, respectively. Among those, linc-A was consistently downregulated during GSC differentiation. Linc-A, of which expression is regulated by the Notch signaling pathway, physically interacted with polycomb repressive complex 2 (PRC2) and conferred a recruitment of PRC2 and histone H3 lysine 27 trimethylation (H3K27me3) in its target loci. An RNA pull-down assay revealed that linc-A specifically bound to a number of neuronal differentiation-associated genes in GSC. These target genes were consistently silenced in GSCs. Inhibition of linc-A using antisense oligonucleotide reduced the H3K27me3 level and increased expression of its target genes, resulted in loss of stemness and induction of GSC differentiation into neuronal lineage. Intriguingly, in silico analysis revealed that linc-A shared a sequence of microRNA-response element (MRE) with mRNAs of stemness markers, such as MYC, SOX2, and NANOG. Indeed, downregulation of linc-A increased the miR-X expression together with repression of its target genes, MYC, SOX2, and NANOG, being consistent with an RNA sponge mechanism, in which lncRNAs contain complementary binding sites (MRE) to a miRNA of interest and prevent these mRNAs from degradation. Our data indicated that linc-A plays consistent roles in modulation of stemness properties in GSC in response to Notch-epigenetic regulatory pathway. Citation Format: Keisuke Katsushima, Keiko Shinjo, Fumiharu Ohka, Atsushi Natsume, Tatsuhiro Shibata, Yutaka Kondo. Role of non-coding RNA in regulation of stemness and differentiation via notch signaling pathway in glioblastoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1394. doi:10.1158/1538-7445.AM2014-1394