title: YBX1 gene silencing inhibits migratory and invasive potential via CORO1C in breast cancer in vitro.
abstract: Y-box binding protein-1 is an evolutionary conserved transcription and translation regulating protein that is overexpressed in various human malignancies, including breast cancer. Despite reports of YB-1 and its association with distant spread of breast cancer, the intrinsic mechanism underlying this observation remains elusive. This study investigates the role of YB-1 in mediating metastasis in highly invasive breast cancer cell lines.
  
  
  
  Silencing the YBX1 gene (which encodes the YB-1 protein) by small interfering RNA (siRNA) was performed in MDA-MB-231 and Hs578T breast cancer cell lines, followed by phenotypic assays including cell migration and invasion assays. Gene expression profiling using Affymetrix GeneChip® Human Transcriptome 2.0 array was subsequently carried out in YB-1 silenced MDA-MB-231 cells. Overexpression and silencing of YBX1 were performed to assess the expression of CORO1C, one of the differentially regulated genes from the transcriptomic analysis. A Gaussia luciferase reporter assay was used to determine if CORO1C is a putative YB-1 downstream target. siRNA-mediated silencing of CORO1C and down-regulation of YBX1 in CORO1C overexpressing MDA-MB-231 cells were performed to evaluate cell migration and invasion.
  
  
  
  Downregulation of the YB-1 protein inhibited cell migration and invasion in MDA-MB-231 breast cancer cells. Global gene expression profiling in the YBX1 silenced MDA-MB-231 cells identified differential expression of several genes, including CORO1C (which encodes for an actin binding protein, coronin-1C) as a potential downstream target of YB-1. While knockdown of YBX1 gene decreased CORO1C gene expression, the opposite effects were seen in YB-1 overexpressing cells. Subsequent verification using the reporter assay revealed that CORO1C is an indirect downstream target of YB-1. Silencing of CORO1C by siRNA in MDA-MB-231 cells was also observed to reduce cell migration and invasion. Silencing of YBX1 caused a similar reduction in CORO1C expression, concomitant with a significant decrease in migration in Hs578T cells. In coronin-1C overexpressing MDA-MB-231 cells, increased migration and invasion were abrogated by YB-1 knockdown.
  
  
  
  It would appear that YB-1 could regulate cell invasion and migration via downregulation of its indirect target coronin-1C. The association between YB-1 and coronin-1C offers a novel approach by which metastasis of breast cancer cells could be targeted and abrogated.
authors.affiliation: Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, Blk MD10, Singapore, 117594, Singapore.|Quantitative Proteomics Group, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, 61 Biopolis Drive, Proteos, Singapore, 138673, Singapore.
authors.forename: Jia Pei
authors.initials: JP
authors.lastname: Lim
authors.affiliation: Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, Blk MD10, Singapore, 117594, Singapore.
authors.forename: Sukanya
authors.initials: S
authors.lastname: Shyamasundar
authors.affiliation: Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, Blk MD10, Singapore, 117594, Singapore.|Quantitative Proteomics Group, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, 61 Biopolis Drive, Proteos, Singapore, 138673, Singapore.
authors.forename: Jayantha
authors.initials: J
authors.lastname: Gunaratne
authors.affiliation: Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, Blk MD10, Singapore, 117594, Singapore.
authors.forename: Olivia Jane
authors.initials: OJ
authors.lastname: Scully
authors.affiliation: Laboratory of Cellular Biochemistry, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Matsumoto
authors.affiliation: Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, Blk MD10, Singapore, 117594, Singapore. boon_huat_bay@nuhs.edu.sg.
authors.forename: Boon Huat
authors.initials: BH
authors.lastname: Bay
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008840:Microfilament Proteins / Q000235:genetics*; D009361:Neoplasm Invasiveness / Q000235:genetics*; D051840:Y-Box-Binding Protein 1 / Q000235:genetics*
chemical_list: D008840:Microfilament Proteins; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; C072061:coronin proteins
keywords: Breast cancer; CORO1C gene; Invasion; Metastasis; Migration; YB-1 protein