title: Effects of long noncoding RNA-ROR on tamoxifen resistance of breast cancer cells by regulating microRNA-205.
abstract: To explore how long noncoding RNA-ROR (lncRNA-ROR) affects the tamoxifen resistance of breast cancer cells.
  
  
  
  Breast epithelial (MCF10A), breast cancer (MCF7), and natural tamoxifen-resistant breast cancer (MDA-MB-231) cell lines were selected, and the relative lncRNA-ROR expressions were detected using quantitative real-time polymerase chain reaction (qRT-PCR). In vitro induction of TR5 cell line was performed. There were six groups: MCF7, MCF7/TR5, MDA-MB-231, MCF7-ROR, MCF7/TR5 ROR-siRNA, and the MDA-MB-231 ROR-siRNA groups. CCK-8 assay was conducted to assess the changes in drug resistance of each group. The expression of the epithelial mesenchymal transition (EMT) marker was detected using Western blotting. Transwell was selected to test the invasive ability of the cells. Expressions of microRNA-205 (miR-205) and ZEB1/2 were detected using qRT-PCR .
  
  
  
  Compared with the MCF7 cells, the proliferation rates of the MCF7/TR5 and MDA-MB-231 cells were significantly increased. Compared with the MCF7 cells, the MCF7-ROR cells had remarkably higher proliferation rates, down-regulated E-cadherin and miR-205 expressions, as well as increased vimentin, invasive ability, and mRNA expression of ZEB1 and ZEB2. Compared with the MCF7/TR5 and MDA-MB-231 cells, up-regulated E-cadherin and miR-205 expression, down-regulated expression of vimentin, ZEB1, and ZEB2 mRNA, and decreased invasive ability were observed in the MCF7/TR5 ROR-siRNA and MDA-MB-231 ROR-siRNA cells.
  
  
  
  In MDA-MB-231 cells, down-regulated lncRNA-ROR could inhibit the EMT of breast cancer cells and enhance the sensibility of breast cancer cells to tamoxifen by increasing miR-205 expression and suppressing the expressions of ZEB1 and ZEB2.
authors.affiliation: Oncology Department, PLA Army General Hospital, No. 5 Nanmencang, Dongcheng District, Beijing, 100700, People's Republic of China. roninzhy@126.com.
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Zhang
authors.affiliation: General Surgery Department, Affiliated Hospital of Academic of Military Medical Science, Beijing, 100071, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liang
authors.affiliation: Oncology Department, PLA Army General Hospital, No. 5 Nanmencang, Dongcheng District, Beijing, 100700, People's Republic of China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Zhang
authors.affiliation: Oncology Department, PLA Army General Hospital, No. 5 Nanmencang, Dongcheng District, Beijing, 100700, People's Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: Oncology Department, PLA Army General Hospital, No. 5 Nanmencang, Dongcheng District, Beijing, 100700, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Oncology Department, PLA Army General Hospital, No. 5 Nanmencang, Dongcheng District, Beijing, 100700, People's Republic of China.
authors.forename: Xi-Gang
authors.initials: XG
authors.lastname: Kang
mesh_terms: D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D035683:MicroRNAs / Q000502:physiology*; D009361:Neoplasm Invasiveness; D062085:RNA, Long Noncoding / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins / Q000235:genetics; D013629:Tamoxifen / Q000627:therapeutic use*; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1 / Q000235:genetics
chemical_list: D018398:Homeodomain Proteins; D035683:MicroRNAs; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D012097:Repressor Proteins; D013629:Tamoxifen; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1; C000588825:Linc-RNA-RoR, human; C534425:MIR205, human; C486307:ZEB1 protein, human; C492363:ZEB2 protein, human
keywords: Breast cancer; Long noncoding RNA-ROR; MicroRNA-205; Tamoxifen resistance