title: Targeting of syndecan-1 by microRNA miR-10b promotes breast cancer cell motility and invasiveness via a Rho-GTPase- and E-cadherin-dependent mechanism.
abstract: microRNAs are small endogenous noncoding RNAs, which post-transcriptionally regulate gene expression. In breast cancer, overexpression of the transmembrane heparan sulfate proteoglycan syndecan-1, a predicted target of the oncomiR miR-10b, correlates with poor clinical outcome. To investigate the potential functional relationship of miR-10b and syndecan-1, MDA-MB-231 and MCF-7 breast cancer cells were transiently transfected with pre-miR-10b, syndecan-1 siRNA or control reagents, respectively. Altered cell behavior was monitored by proliferation, migration and invasion chamber assays, and time-lapse video microscopy. miR-10b overexpression induced post-transcriptional downregulation of syndecan-1, as demonstrated by quantitative real-time PCR (qPCR), flow cytometry, and 3'UTR luciferase assays, resulting in increased cancer cell migration and matrigel invasiveness. Syndecan-1 silencing generated a copy of this phenotype. Adhesion to fibronectin and laminin and basal cell proliferation was increased. Syndecan-1 coimmunoprecipitated with focal adhesion kinase, which showed increased activation upon syndecan-1 depletion. Affymetrix screening and confirmatory qPCR and Western blotting analysis of syndecan-1-deficient cells revealed upregulation of ATF-2, COX-2, cadherin-11, vinculin, actin γ 2, MYL9, transgelin-1, RhoA/C, matrix metalloproteinase 2 (MMP2) and heparanase, and downregulation of AML1/RUNX1, E-cadherin, CLDN1, p21WAF/CIP, cyclin-dependent kinase 6, TLR-4, PAI1/2, Collagen1alpha1, JHDM1D, Mpp4, MMP9, matrilin-2 and ANXA3/A10. Video microscopy demonstrated massively increased Rho kinase-dependent motility of syndecan-1-depleted cells, which displayed increased filopodia formation. We conclude that syndecan-1 is a novel target of the oncomiR miR-10b. Rho-GTPase-dependent modulation of cytoskeletal function and downregulation of E-cadherin expression are identified as relevant effectors of the miR-10b-syndecan-1 axis, which emerges as a promising target for the development of new therapeutic approaches for breast cancer.
authors.affiliation: Department of Gynecology and Obstetrics, Münster University Hospital, Münster, Germany.
authors.forename: Sherif A
authors.initials: SA
authors.lastname: Ibrahim
authors.forename: George W
authors.initials: GW
authors.lastname: Yip
authors.forename: Christian
authors.initials: C
authors.lastname: Stock
authors.forename: Jun-Wei
authors.initials: JW
authors.lastname: Pan
authors.forename: Claudia
authors.initials: C
authors.lastname: Neubauer
authors.forename: Michaela
authors.initials: M
authors.lastname: Poeter
authors.forename: Danute
authors.initials: D
authors.lastname: Pupjalis
authors.forename: Chuay Yeng
authors.initials: CY
authors.lastname: Koo
authors.forename: Reinhard
authors.initials: R
authors.lastname: Kelsch
authors.forename: Roland
authors.initials: R
authors.lastname: Schüle
authors.forename: Ursula
authors.initials: U
authors.lastname: Rescher
authors.forename: Ludwig
authors.initials: L
authors.lastname: Kiesel
authors.forename: Martin
authors.initials: M
authors.lastname: Götte
mesh_terms: D051698:Activating Transcription Factor 2 / Q000235:genetics; D001943:Breast Neoplasms / Q000473:pathology*; D015820:Cadherins / Q000502:physiology*; D002450:Cell Communication; D045744:Cell Line, Tumor; D002465:Cell Movement; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics; D018450:Disease Progression; D005260:Female; D006801:Humans; D035683:MicroRNAs / Q000502:physiology*; D009361:Neoplasm Invasiveness; D010766:Phosphorylation; D012333:RNA, Messenger / Q000032:analysis; D034741:RNA, Small Interfering / Q000235:genetics; D053668:Syndecan-1 / Q000037:antagonists & inhibitors* / Q000502:physiology; D020741:rho GTP-Binding Proteins / Q000502:physiology*
chemical_list: C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; D015820:Cadherins; D050676:Core Binding Factor Alpha 2 Subunit; C547183:MIRN10 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C493728:RUNX1 protein, human; C508241:SDC1 protein, human; D053668:Syndecan-1; D020741:rho GTP-Binding Proteins