title: BUB1 and BUBR1 inhibition decreases proliferation and colony formation, and enhances radiation sensitivity in pediatric glioblastoma cells.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Genetics, University of São Paulo, Av. Bandeirantes, 3900, Bairro Monte Alegre, 14048-900, Ribeirão Preto, Sao Paulo, Brazil.
authors.forename: Andressa Gois
authors.initials: AG
authors.lastname: Morales
authors.forename: Julia Alejandra
authors.initials: JA
authors.lastname: Pezuk
authors.forename: María Sol
authors.initials: MS
authors.lastname: Brassesco
authors.forename: Jaqueline Carvalho
authors.initials: JC
authors.lastname: de Oliveira
authors.forename: Rosane Gomes
authors.initials: RG
authors.lastname: de Paula Queiroz
authors.forename: Hélio Rubens
authors.initials: HR
authors.lastname: Machado
authors.forename: Carlos Gilberto
authors.initials: CG
authors.lastname: Carlotti
authors.forename: Luciano
authors.initials: L
authors.lastname: Neder
authors.forename: Harley Francisco
authors.initials: HF
authors.lastname: de Oliveira
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Scrideli
authors.forename: Luiz Gonzaga
authors.initials: LG
authors.lastname: Tone
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008297:Male; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering; D011836:Radiation Tolerance / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D059467:Transcriptome
chemical_list: D034741:RNA, Small Interfering; C584277:BUB1 protein, human; D017346:Protein Serine-Threonine Kinases