Abstract 3765: Long non-coding RNAs are dysregulated in glioblastoma and LINC00634 may affect the diffuse growth of U251-derived tumors in vivo
Authors: Vecera Marek , Radova Lenka , Lipina Radim , Reguli Stefan , Smrcka Martin , Jancalek Radim , Filip Michal , Hermanova Marketa , Kren Leos , Tukmachi Dagmar Al , Machackova Tana , Pokorna Petra , Sana Jiri , Slaby Ondrej 
Published: April 2023

Introduction: Glioblastoma (GBM) is the most frequent primary astrocytoma characterized by an aggressive and diffuse growth and a poor prognosis. The median survival of patients with GBM is only 12 to 16 months from diagnosis despite conventional therapy. It is, therefore, important to identify new therapeutic targets, which would allow a more effective treatment. In our present study, we focus on long non-coding RNAs (lncRNAs), the regulators of gene expression in both physiological conditions and GBM pathology, and their potential as targets for future therapy.

Material and Methods: Our study included 219 GBM patients and 29 intractable epilepsy patients as controls who signed an informed consent prior to treatment. Previously, cDNA libraries were prepared from 77 rRNA-depleted RNA samples and sequenced, and the expression of 11 significantly dysregulated lncRNAs was validated in 188 specimens by RT-qPCR. Results were newly validated in an independent TCGA-GBM cohort. Moreover, LINC00634 expression was upregulated in U251 and T98G cells. Cells transfected with an empty vector served as negative controls (NCs). The effect of upregulated LINC00634 expression on viability, migration, and clonogenicity was studied in vitro, and, in the case of U251-derived cell line, in vivo in immunodeficient mice with the focus on GBM growth and diffuse character.

Results: Out of the 538 significantly dysregulated lncRNAs (P &lt; 0.001) identified by transcriptome sequencing, a panel of 10 downregulated lncRNAs (SNAI3-AS1, LINC00882, RFPL1S, MIR137HG, TTLL7-IT1, PWAR6, LINC00634, LINC00632, DGCR5, LINC00982; logFC ≤ -2; P &lt; 0.001) and 1 upregulated lncRNA (BTN2A3P; logFC ≥ 2; P &lt; 0.001) in GBM was validated previously by qPCR in another cohort (P &lt; 0.0001 for all lncRNAs) and newly in an independent TCGA-GBM dataset. The upregulated LINC00634 expression in U251 and T98G cells was confirmed by qPCR to be approximately 11,000-fold and 600-fold, respectively, compared to the expression in NCs. Although no significant effect on viability, migration and clonogenicity was observed in vivo, a less diffuse growth pattern was observed in U251-derived GBMs with upregulated expression of LINC00634 in vivo compared with NCs.

Conclusion: A significant dysregulation of lncRNAs was previously observed in GBM compared to non-tumor controls using both transcriptome sequencing and RT-qPCR and was newly confirmed also by analyzing the TCGA-GBM dataset. We also showed possible effect of LINC00634 upregulation on the growth pattern of U251-derived GBM tumors in vivo. Our study shows that lncRNAs are dysregulated in GBM and could, therefore, serve as promising diagnostic biomarkers in GBM as well as potential therapeutic targets. The research was supported by the project National Institute for Cancer Research (Programme EXCELES, ID Project No. LX22NPO5102, funded by the European Union - Next Generation EU).

Citation Format: Marek Vecera, Lenka Radova, Radim Lipina, Stefan Reguli, Martin Smrcka, Radim Jancalek, Michal Filip, Marketa Hermanova, Leos Kren, Dagmar Al Tukmachi, Tana Machackova, Petra Pokorna, Jiri Sana, Ondrej Slaby. Long non-coding RNAs are dysregulated in glioblastoma and LINC00634 may affect the diffuse growth of U251-derived tumors in vivo. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3765.