title: Y-box binding protein-1 (YB-1) promotes cell cycle progression through CDC6-dependent pathway in human cancer cells.
abstract: Y-box binding protein-1 (YB-1) plays pivotal roles in acquisition of global drug resistance and cell growth promotion through transcriptional activation of genes for both drug resistance and growth factor receptors. In this study, we investigated whether YB-1 is involved in regulation of the cell cycle and cell proliferation of human cancer cells. Treatment with YB-1 siRNA caused a marked suppression of cell proliferation and expression of a cell cycle related gene, CDC6 by cancer cells. Of cell cycle of cancer cells, S phase content was specifically reduced by knockdown of YB-1. The overexpression of CDC6 abrogated this inhibition of both cell proliferation and S phase entry. ChIP assay demonstrated that YB-1 binds to a Y-box located in the promoter region of the CDC6 gene. Expression of cyclin D1, CDK1 and CDK2 was also reduced with increased expression of p21(Cip1) and p16(INK4A) when treated with YB-1 siRNA. Furthermore, the nuclear YB-1 expression was significantly associated with the level of CDC6 nuclear expression in patients with breast cancer. In conclusion, YB-1 plays an important role in cell cycle progression at G1/S of human cancer cells. YB-1 thus could be a potent biomarker for tumour growth and cell cycle in its close association with CDC6.
authors.affiliation: Department of Pharmaceutical Oncology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Basaki
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Taguchi
authors.forename: Hiroto
authors.initials: H
authors.lastname: Izumi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Murakami
authors.forename: Takuya
authors.initials: T
authors.lastname: Kubo
authors.forename: Fumihito
authors.initials: F
authors.lastname: Hosoi
authors.forename: Kosuke
authors.initials: K
authors.lastname: Watari
authors.forename: Kenji
authors.initials: K
authors.lastname: Nakano
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Shinji
authors.initials: S
authors.lastname: Ohno
authors.forename: Kimitoshi
authors.initials: K
authors.lastname: Kohno
authors.forename: Mayumi
authors.initials: M
authors.lastname: Ono
authors.forename: Michihiko
authors.initials: M
authors.lastname: Kuwano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D049109:Cell Proliferation; D005260:Female; D006801:Humans; D007564:Japan; D008875:Middle Aged; D009687:Nuclear Proteins / Q000378:metabolism*; D051840:Y-Box-Binding Protein 1 / Q000378:metabolism*; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C103706:CDC6 protein, human; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D051840:Y-Box-Binding Protein 1