ADAR1-mediated RNA editing links ganglioside catabolism to glioblastoma stem cell maintenance
Li Jiang, … , Xiang-Dong Fu, Jeremy N. Rich
Li Jiang, … , Xiang-Dong Fu, Jeremy N. Rich
Published February 8, 2022
Citation Information: J Clin Invest. 2022;132(6):e143397. https://doi.org/10.1172/JCI143397.
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Research Article Oncology

ADAR1-mediated RNA editing links ganglioside catabolism to glioblastoma stem cell maintenance

Abstract

Glioblastoma (GBM) is the most common and lethal primary malignant brain tumor, containing GBM stem cells (GSCs) that contribute to therapeutic resistance and relapse. Exposing potential GSC vulnerabilities may provide therapeutic strategies against GBM. Here, we interrogated the role of adenosine-to-inosine (A-to-I) RNA editing mediated by adenosine deaminase acting on RNA 1 (ADAR1) in GSCs and found that both ADAR1 and global RNA editomes were elevated in GSCs compared with normal neural stem cells. ADAR1 inactivation or blocking of the upstream JAK/STAT pathway through TYK2 inhibition impaired GSC self-renewal and stemness. Downstream of ADAR1, RNA editing of the 3′-UTR of GM2A, a key ganglioside catabolism activator, proved to be critical, as interference with ganglioside catabolism and disruption of ADAR1 showed a similar functional impact on GSCs. These findings reveal that RNA editing links ganglioside catabolism to GSC self-renewal and stemness, exposing a potential vulnerability of GBM for therapeutic intervention.

Authors

Li Jiang, Yajing Hao, Changwei Shao, Qiulian Wu, Briana C. Prager, Ryan C. Gimple, Gabriele Sulli, Leo J.Y. Kim, Guoxin Zhang, Zhixin Qiu, Zhe Zhu, Xiang-Dong Fu, Jeremy N. Rich

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Figure 4

GM2A maintains GSC survival, proliferation, and self-renewal.

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GM2A maintains GSC survival, proliferation, and self-renewal. See also T...
See also Table 2. (A) Gene expression levels of GM2A in normal brain or gliomas in the TCGA database. Statistical significance was determined by Wilcoxon’s signed-rank test. **P < 0.01. (B) Kaplan-Meier survival curves of glioma patients with high or low GM2A expression in TCGA. P value was determined by log-rank test. (C) Left: Comparative GM2A mRNA expression in NSCs (NSC11 and WT83) and GSCs (1517, 3565, and 3691) by reverse transcriptase PCR. n = 4. Statistical significance was determined by ANOVA. ***P < 0.001. Right: Western blotting for GM2A in NSCs (NSC11 and WT83) and GSCs (1517, 3565, and 3691). β-Actin served as loading control. (D) Western blotting for ADAR1 and GM2A in matched GSCs and DGCs. GFAP and SOX2 served as markers of differentiated or stem/progenitor cells. β-Actin served as loading control. (E) GM2A mRNA expression in GSCs (1517, 3565, and 3691) transduced with shCONT or shGM2A. na, not available. n = 4. Quantitative data from 4 independent experiments are shown as mean ± SD (error bars). Statistical significance was determined by ANOVA. **P < 0.01, ***P < 0.001. (F) Western blotting for GM2A, PARP, and cleaved caspase-3 in GSCs (1517, 3565, and 3691) transduced with shCONT or shGM2A. β-Actin served as loading control. Arrowhead indicates cleaved PARP. (G) Proliferation of GSCs (1517, 3565, and 3691) transduced with shCONT or shGM2A as determined by CellTiter-Glo. Quantitative data from 5 technical experiments are shown as mean ± SD (error bars). n = 5. Statistical significance was determined by 2-way ANOVA with Dunnett’s multiple-comparison test. ****P < 0.0001. (H) ELDA for in vitro sphere formation of GSCs (1517, 3565, and 3691) transduced with shCONT or shGM2A. n = 24. Pairwise tests for differences in stem cell frequencies. ***P < 0.001.