BUB1 and BUBR1 inhibition decreases proliferation and colony formation, and enhances radiation sensitivity in pediatric glioblastoma cells
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Glioblastoma (GBM) is a very aggressive and lethal brain tumor with poor prognosis. Despite new treatment strategies, patients’ median survival is still lower than 1 year in most cases. The expression of the BUB gene family has demonstrated to be altered in a variety of solid tumors, pointing to a role as putative therapeutic target. The purpose of this study was to determine BUB1, BUB3, and BUBR1 gene expression profiles in glioblastoma and to analyze the effects of BUB1 and BUBR1 inhibition combined or not with Temozolomide and radiation in the pediatric SF188 GBM cell line.
For gene expression analysis, 8 cell lines and 18 tumor samples were used. The effect of BUB1 and BUBR1 inhibition was evaluated using siRNA. Apoptosis, cell proliferation, cell cycle kinetics, micronuclei formation, and clonogenic capacity were analyzed after BUB1 and BUBR1 inhibition. Additionally, combinatorial effects of gene inhibition and radiation or Temozolomide (TMZ) treatment were evaluated through proliferation and clonogenic capacity assays.
We report the upregulation of BUB1 and BUBR1 expression and the downregulation of BUB3 in GBM samples and cell lines when compared to white matter samples (p < 0.05). Decreased cell proliferation and colony formation after BUB1 and BUBR1 inhibition were observed, along with increased micronuclei formation. Combinations with TMZ also caused cell cycle arrest and increased apoptosis. Moreover, our results demonstrate that BUB1 and BUBR1 inhibition sensitized SF188 cells to γ-irradiation as shown by decreased growth and abrogation of colony formation capacity.
BUB1 and BUBR1 inhibition decreases proliferation and shows radiosensitizing effects on pediatric GBM cells, which could improve treatment strategies for this devastating tumor. Collectively, these findings highlight the potentials of BUB1 and BUBR1 as putative therapeutic targets for glioblastoma treatment.
KeywordsMitotic checkpoint genes Glioblastoma Cell cycle Interference RNA
We are grateful to BSc Veridiana Kiill Suazo for technical assistance. We also thank the Fundação de Apoio a Pesquisa do Estado de São Paulo (FAPESP; 2009/50118-2 and 2009/09305-3) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support.
- 5.MacDonald TJ, Aguilera D, Kramm CM (2011) Treatment of high-grade glioma in children and adolescents. Neuro-Oncology 1–10Google Scholar
- 33.Ricke RM, Jeganathan KB, Deursen JM (2011) Bub1 overexpression induces aneuploidy and tumor formation through Aurora B kinase hyperactivation. J Cell Biol 6:1–16Google Scholar
- 37.Kleihues P, Burger PC, Adalpe, KD, Brat, DJ, Biernat W, Bigner DD, Nakazato Y, Plate KH, Giangaspero F, Deimling AV, Ohgak H, Cavenee WK. Gliolastoma (2007) WHO classification of tumors of the central nervous system. In: Louis DN, Ohgaki H, Wiesther OD, Cavenee WK. (Eds). International Agency for Research on Cancer, Lion, 4th ed. pp. 33–49.Google Scholar
- 52.Morandi E, Severini C, Quercioli D, D’Ario G, Perdichizzi S, Capri M et al (2008) Gene expression time-series analysis of camptothecin effects in U87-MG and DBTRG-05 glioblastoma cell lines. Mol Cancer 11:7–66Google Scholar