title: Sodium selenite alters microtubule assembly and induces apoptosis in vitro and in vivo.
abstract: BACKGROUND
  Previous studies demonstrated that selenite induced cancer-cell apoptosis through multiple mechanisms; however, effects of selenite on microtubules in leukemic cells have not been demonstrated.
  
  
  METHODS
  The toxic effect of selenite on leukemic HL60 cells was performed with cell counting kit 8. Selenite effects on cell cycle distribution and apoptosis induction were determined by flow cytometry. The contents of cyclin B1, Mcl-1, AIF, cytochrome C, insoluble and soluble tubulins were detected with western blotting. Microtubules were visualized with indirect immunofluorescence microscopy. The interaction between CDK1 and Mcl-1 was assessed with immunoprecipitation. Decreasing Mcl-1 and cyclin B1 expression were carried out through siRNA interference. The alterations of Mcl-1 and cyclin B1 in animal model were detected with either immunohistochemical staining or western blotting. In situ detection of apoptotic ratio was performed with TUNEL assay.
  
  
  RESULTS
  Our current results showed that selenite inhibited the growth of HL60 cells and induced mitochondrial-related apoptosis. Furthermore, we found that microtubule assembly in HL60 cells was altered, those cells were arrested at G2/M phase, and Cyclin B1 was up-regulated and interacted with CDK1, which led to down-regulation of the anti-apoptotic protein Mcl-1. Finally, in vivo experiments confirmed the in vitro microtubule disruption effect and alterations in Cyclin B1 and Mcl-1 levels by selenite.
  
  
  CONCLUSIONS
  Taken together, the results from our study indicate that microtubules are novel targets of selenite in leukemic HL60 cells.
authors: State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, CAMS & PUMC, Beijing 100005, China.
authors: Kejian
authors: K
authors: Shi
authors: Qian
authors: Q
authors: Jiang
authors: Zhushi
authors: Z
authors: Li
authors: Lei
authors: L
authors: Shan
authors: Feng
authors: F
authors: Li
authors: JiaJia
authors: J
authors: An
authors: Yang
authors: Y
authors: Yang
authors: Caimin
authors: C
authors: Xu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002135:Calcium-Binding Proteins; D002455:Cell Division / Q000187:drug effects*; D056744:Cyclin B1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D016195:G2 Phase / Q000187:drug effects*; D018922:HL-60 Cells; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D020287:In Situ Nick-End Labeling; D066298:In Vitro Techniques; D051379:Mice; D008840:Microfilament Proteins; D008870:Microtubules / Q000187:drug effects* / Q000502:physiology; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D018038:Sodium Selenite / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
chemical_list: C112986:AIF1 protein, human; D002135:Calcium-Binding Proteins; D056744:Cyclin B1; D004268:DNA-Binding Proteins; C579094:Mcl1 protein, mouse; D008840:Microfilament Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D045304:Cytochromes c; D018038:Sodium Selenite