Abstract
Changes in epigenetic programming are associated with cancer development during childhood. Components of the epigenetic machinery involved in normal embryonic development and hijacked by pediatric cancers include enzymes mediating post-translational modifications of DNA and histones that regulate chromatin structure, such as histone methyltransferases (HMTs). Overexpression of the HMT G9a (euchromatic histone lysine methyltransferase 2, EHMT2) has been described in several cancer types. Medulloblastoma (MB), the main type of malignant brain tumor afflicting children, is currently classified into four molecular subgroups. Here, we show that expression level of the G9a/Ehmt2 gene is higher in MB tumors belonging to the SHH, Group 3, and Group 4 subgroups, compared to Wnt tumors. Remarkably, high G9a expression was significantly associated with shorter overall survival in MB patients. We also present evidence that G9a inhibition dose-dependently reduces MB cell viability. Our findings suggest that higher transcription of G9a may be a predictor of poor prognosis in patients with SHH MB, and that inhibiting G9a activity can display antitumor effects in MB.
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The Cavalli cohort (Cavalli et al., 2017) profiled on the Affymetrix Gene 1.1 ST array and normalized using the RMA method). Expression of the markers across all samples was normalized within the R2: Genomics Analysis and Visualization Platform (http://r2.amc.nl) and presented in box plot format as log2-transformed signal intensity. All subgroups and subtypes in each data set were compared using a Kruskal–Wallis test for significance and Tukey’s tests for post hoc analysis, using GraphPad Prism; p < 0.001 was considered to indicate statistically significant differences. B Overall survival (OS) was measured from the time of initial diagnosis to the date of death or the date of last follow up, using combined OS and gene expression data from all data sets selected. Survival distribution was estimated according to the Kaplan–Meier method using a median cut-off and log-rank statistics; p ≤ 0.05 was considered statistically significant
References
Baxter, E., Windloch, K., Gannon, F., & Lee, J. S. (2014). Epigenetic regulation in cancer progression. Cell & Bioscience, 4, 45. https://doi.org/10.1186/2045-3701-4-45
Brown, S. E., Campbell, R. D., & Sanderson, C. M. (2001). Novel NG36/G9a gene products encoded within the human and mouse MHC class III regions. Mammalian Genome, 12, 916–924. https://doi.org/10.1007/s00335-001-3029-3
Casciello, F., Windloch, K., Gannon, F., & Lee, J. S. (2015). Functional role of G9a histone methyltransferase in cancer. Frontiers in Immunology, 6, 487. https://doi.org/10.3389/fimmu.2015.00487
Cavalli, F.M.G., Remke, M., Rampasek, L., Peacock, J., Shih, D.J.H., Luu, B., Garzia, L., Torchia, J., Nör, C., Morrissy, A.S., Agnihotri, S., Thompson, Y.Y., Kuzan-Fischer, C.M., Farooq, H., Isaev, K., Daniels, C., Cho, B.K., Kim, S.K., Wang, K.C., … Taylor, M.D. (2017). Intertumoral heterogeneity within medulloblastoma subgroups. Cancer Cell, 31, 737–754.e6. https://doi.org/10.1016/j.ccell.2017.05.005
Chen, M. W., Hua, K. T., Kao, H. J., Chi, C. C., Wei, L. H., Johansson, G., Shiah, S. G., Chen, P. S., Jeng, Y. M., Cheng, T. Y., Lai, T. C., Chang, J. S., Jan, Y. H., Chien, M. H., Yang, C. J., Huang, M. S., Hsiao, M., & Kuo, M. L. (2010). H3K9 histone methyltransferase G9a promotes lung cancer invasion and metastasis by silencing the cell adhesion molecule Ep-CAM. Cancer Research, 70, 7830–7840. https://doi.org/10.1158/0008-5472.CAN-10-0833
Dobson, T. H. W., Hatcher, R. J., Swaminathan, J., Das, C. M., Shaik, S., Tao, R. H., Milite, C., Castellano, S., Taylor, P. H., Sbardella, G., & Gopalakrishnan, V. (2017). Regulation of USP37 expression by REST-associated G9a-dependent histone methylation. Molecular Cancer Research, 15, 1073–1084. https://doi.org/10.1158/1541-7786.MCR-16-0424
Ellis, L., Atadja, P. W., & Johnstone, R. W. (2009). Epigenetics in cancer: Targeting chromatin modifications. Molecular Cancer Therapeutics, 8, 1409–1420. https://doi.org/10.1158/1535-7163.MCT-08-0860
Ivanov, D. P., Coyle, B., Walker, D. A., & Grabowska, A. M. (2016). In vitro models of medulloblastoma: Choosing the right tool for the job. Journal of Biotechnology, 236, 10–25. https://doi.org/10.1016/j.jbiotec.2016.07.028
Kouzarides, T. (2007). Chromatin modifications and their function. Cell, 128, 693–705. https://doi.org/10.1016/j.cell.2007.02.005
Lawlor, E. R., & Thiele, C. J. (2012). Epigenetic changes in pediatric solid tumors: Promising new targets. Clinical Cancer Research, 18, 2768–2779. https://doi.org/10.1158/1078-0432.CCR-11-1921
Lehnertz, B., Ueda, Y., Derijck, A. A., Braunschweig, U., Perez-Burgos, L., Kubicek, S., Chen, T., Li, E., Jenuwein, T., & Peters, A. H. (2003). Suv39h-mediated histone H3 lysine 9 methylation directs DNA methylation to major satellite repeats at pericentric heterochromatin. Current Biology, 13, 1192–1200. https://doi.org/10.1016/s0960-9822(03)00432-9
Milner, C. M., & Campbell, R. D. (1993). The G9a gene in the human major histocompatibility complex encodes a novel protein containing ankyrin-like repeats. Biochemical Journal, 290(Pt 3), 811–818. https://doi.org/10.1042/bj2900811
Morera, L., Lübbert, M., & Jung, M. (2016). Targeting histone methyltransferases and demethylases in clinical trials for cancer therapy. Clinical Epigenetics, 8, 57. https://doi.org/10.1186/s13148-016-0223-4
Northcott, P.A., Buchhalter, I., Morrissy, A.S., Hovestadt, V., Weischenfeldt, J., Ehrenberger, T., Gröbner, S., Segura-Wang, M., Zichner, T., Rudneva, V.A., Warnatz, H.J., Sidiropoulos, N., Phillips, A.H., Schumacher, S., Kleinheinz, K., Waszak, S.M., Erkek, S., Jones, D.T.W., Worst, B.C., … Lichter, P. (2017). The whole-genome landscape of medulloblastoma subtypes. Nature, 547, 311–317. https://doi.org/10.1038/nature22973
Northcott, P. A., Korshunov, A., Pfister, S. M., & Taylor, M. D. (2012). The clinical implications of medulloblastoma subgroups. Nature Reviews Neurology, 8, 340–351. https://doi.org/10.1038/nrneurol.2012.78
Northcott, P. A., Robinson, G. W., Kratz, C. P., Mabbott, D. J., Pomeroy, S. L., Clifford, S. C., Rutkowski, S., Ellison, D. W., Malkin, D., Taylor, M. D., Gajjar, A., & Pfister, S. M. (2019). Medulloblastoma. Nature Reviews Disease Primers, 5, 11. https://doi.org/10.1038/s41572-019-0063-6
Schwalbe, E. C., Lindsey, J. C., Nakjang, S., Crosier, S., Smith, A. J., Hicks, D., Rafiee, G., Hill, R. M., Iliasova, A., Stone, T., Pizer, B., Michalski, A., Joshi, A., Wharton, S. B., Jacques, T. S., Bailey, S., Williamson, D., & Clifford, S. C. (2017). Novel molecular subgroups for clinical classification and outcome prediction in childhood medulloblastoma: A cohort study. Lancet Oncology, 18, 958–971. https://doi.org/10.1016/S1470-2045(17)30243-7
Sharma, T., Schwalbe, E.C., Williamson, D., Sill, M., Hovestadt, V., Mynarek, M., Rutkowski, S., Robinson, G.W., Gajjar, A., Cavalli, F., Ramaswamy, V., Taylor, M.D., Lindsey, J.C., Hill, R.M., Jäger, N., Korshunov, A., Hicks, D., Bailey, S., Kool, M., … Clifford, S.C. (2019). Second-generation molecular subgrouping of medulloblastoma: An international meta-analysis of Group 3 and Group 4 subtypes. Acta Neuropathologica, 138, 309–326. https://doi.org/10.1007/s00401-019-02020-0
Souza, B. K., da Costa Lopez, P. L., Menegotto, P. R., Vieira, I. A., Kersting, N., Abujamra, A. L., Brunetto, A. T., Brunetto, A. L., Gregianin, L., de Farias, C. B., Thiele, C. J., & Roesler, R. (2018). Targeting histone deacetylase activity to arrest cell growth and promote neural differentiation in Ewing sarcoma. Molecular Neurobiology, 55, 7242–7258. https://doi.org/10.1007/s12035-018-0874-6
Souza, B. K., Freire, N. H., Jaeger, M., de Farias, C. B., Brunetto, A. L., Brunetto, A. T., & Roesler, R. (2021). EHMT2/G9a as an epigenetic target in pediatric and adult brain tumors. International Journal of Molecular Sciences, 22, 11292. https://doi.org/10.3390/ijms222011292
Tachibana, M., Ueda, J., Fukuda, M., Takeda, N., Ohta, T., Iwanari, H., Sakihama, T., Kodama, T., Hamakubo, T., & Shinkai, Y. (2005). Histone methyltransferases G9a and GLP form heteromeric complexes and are both crucial for methylation of euchromatin at H3–K9. Genes & Development, 19, 815–826. https://doi.org/10.1101/gad.1284005
Taylor, M. D., Northcott, P. A., Korshunov, A., Remke, M., Cho, Y. J., Clifford, S. C., Eberhart, C. G., Parsons, D. W., Rutkowski, S., Gajjar, A., Ellison, D. W., Lichter, P., Gilbertson, R. J., Pomeroy, S. L., Kool, M., & Pfister, S. M. (2012). Molecular subgroups of medulloblastoma: The current consensus. Acta Neuropathologica, 123, 465–472. https://doi.org/10.1007/s00401-011-0922-z
Thomaz, A., Jaeger, M., Brunetto, A. L., Brunetto, A. T., Gregianin, L., de Farias, C. B., Ramaswamy, V., Nör, C., Taylor, M. D., & Roesler, R. (2020). Neurotrophin signaling in medulloblastoma. Cancers (Basel), 12, 2542. https://doi.org/10.3390/cancers12092542
von Bueren, A.O., Kortmann, R.D., von Hoff, K., Friedrich, C., Mynarek, M., Müller, K., Goschzik, T., Zur Mühlen, A., Gerber, N., Warmuth-Metz, M., Soerensen, N., Deinlein, F., Benesch, M., Zwiener, I., Kwiecien, R., Faldum, A., Bode, U., Fleischhack, G., Hovestadt, V., … Rutkowski, S. (2016). Treatment of children and adolescents with metastatic medulloblastoma and prognostic relevance of clinical and biologic parameters. Journal of Clinical Oncology, 34, 4151–4160. https://doi.org/10.1200/JCO.2016.67.2428
Zwergel, C., Romanelli, A., Stazi, G., Besharat, Z. M., Catanzaro, G., Tafani, M., Valente, S., & Mai, A. (2018). Application of small epigenetic modulators in pediatric medulloblastoma. Frontiers in Pediatrics, 6, 370. https://doi.org/10.3389/fped.2018.00370
Acknowledgements
This research was supported by the National Council for Scientific and Technological Development (CNPq, MCTI, Brazil) Grants 407765/2017-4 and 305647/2019-9 (R.R.), Rio Grande do Sul State Research Foundation (FAPERGS, RS, Brazil) Grant 17/2551-0001 071-0 (R.R.), the Children’s Cancer Institute; the Coordination for the Improvement of Higher Education Personnel (CAPES, MEC, Brazil), the Clinical Hospital Institutional Research Fund (FIPE-HCPA), and Epigenica Biosciences. The data reported in this article have been partially included in a preprint (https://doi.org/10.20944/preprints202108.0335.v1). Authors thank Dr. Marialva Sinigaglia for assistance in preparing the figures.
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BKS and NHF carried out the gene expression analyses and experiments. All authors contributed to the experimental design, study conception, statistical analysis, data interpretation, writing, and revision of this article.
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B.K.S. is co-founder and CEO of Epigenica Biosciences Ltd. The authors declare that they have no other conflict of interest.
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Souza, B.K., Freire, N.H., Jaeger, M. et al. G9a/EHMT2 is a Potential Prognostic Biomarker and Molecular Target in SHH Medulloblastoma. Neuromol Med 24, 392–398 (2022). https://doi.org/10.1007/s12017-022-08702-5
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DOI: https://doi.org/10.1007/s12017-022-08702-5