title: Kisspeptin-10 inhibits bone-directed migration of GPR54-positive breast cancer cells: Evidence for a dose-window effect.
abstract: OBJECTIVE
  The KiSS-1 gene product is absent or expressed at low level in metastatic breast cancer compared with their nonmetastatic counterparts. A deca-peptide derived from the KiSS-1 gene product, designated kisspeptin-10 (Kp-10), activates a receptor coupled to Gαq subunits (GPR54 or KiSS-1R). In this study we have analyzed whether Kp-10 treatment affects bone-directed migration of GPR54-positive breast cancer cells.
  
  
  METHODS
  GPR54 expression was analyzed using immune cytochemistry. Bone-directed breast cancer cell invasion was measured by assessment of the breast cancer cell migration rate through an artificial basement membrane. Chemokine receptor CXCR4 and stromal cell-derived factor-1 (SDF-1) mRNA expression was quantified using semi-quantitative RT-PCR. CXCR4 protein expression and SDF-1 protein secretion were measured using the western blot technique.
  
  
  RESULTS
  Breast cancer cell invasion was increased when cocultured with MG63 osteoblast-like cells. Treatment with KP-10 reduced the ability to invade a reconstituted basement membrane and to migrate in response to the cellular stimulus. This effect was significant in a dose-window of 10⁻⁹ M to 10⁻¹¹ M. Searching for the molecular mechanisms we found that KP-10 treatment significantly reduces expression of the chemokine receptor CXCR4 by the breast cancer cells. In addition, expression and secretion of its ligand SDF-1 by the MG63 cells were significantly reduced. Furthermore, SDF-1-induced CXCR4 signaling was down-regulated.
  
  
  CONCLUSIONS
  These data represent the first report that KP-10 inhibits bone-directed migration of GPR54-positive breast cancer cells. In addition, we found evidence for a KP-10 dose-window effect. Furthermore, the SDF-1/CXCR4 system seems to be involved in the anti-migratory action of KP-10.
authors.affiliation: Department of Gynecology and Obstetrics, Georg-August-University, Göttingen, Germany.
authors.forename: Teresa
authors.initials: T
authors.lastname: Olbrich
authors.forename: Elke
authors.initials: E
authors.lastname: Ziegler
authors.forename: Gregor
authors.initials: G
authors.lastname: Türk
authors.forename: Antje
authors.initials: A
authors.lastname: Schubert
authors.forename: Günter
authors.initials: G
authors.lastname: Emons
authors.forename: Carsten
authors.initials: C
authors.lastname: Gründker
mesh_terms: D001859:Bone Neoplasms / Q000473:pathology; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002450:Cell Communication / Q000187:drug effects* / Q000502:physiology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects* / Q000502:physiology; D054377:Chemokine CXCL12 / Q000096:biosynthesis / Q000235:genetics; D018920:Coculture Techniques; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D059648:Kisspeptins; D051058:Oncogene Protein v-akt / Q000378:metabolism; D018215:Osteoblastoma / Q000473:pathology; D010006:Osteoblasts / Q000473:pathology*; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D019718:Receptors, CXCR4 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis*; D000074502:Receptors, Kisspeptin-1; D015398:Signal Transduction / Q000187:drug effects; D025521:Tumor Suppressor Proteins / Q000494:pharmacology*
chemical_list: C527276:CXCR4 protein, human; D054377:Chemokine CXCL12; C106628:KISS1 protein, human; C118688:KISS1R protein, human; D059648:Kisspeptins; D012333:RNA, Messenger; D019718:Receptors, CXCR4; D043562:Receptors, G-Protein-Coupled; D000074502:Receptors, Kisspeptin-1; D025521:Tumor Suppressor Proteins; D051058:Oncogene Protein v-akt