title: Blocking Wnt/LRP5 signaling by a soluble receptor modulates the epithelial to mesenchymal transition and suppresses met and metalloproteinases in osteosarcoma Saos-2 cells.
abstract: We previously reported the Wnt receptor low-density lipoprotein receptor-related protein 5 (LRP5) was frequently expressed in osteosarcoma (OS) tissue and correlated with metastasis and a lower disease-free survival. Subsequent in vitro analysis revealed that dominant-negative, soluble LRP5 (sLRP5) can reduce in vitro cellular invasion. In the current study, we examined the molecular mechanisms of blocking canonical Wnt signaling by sLRP5 in Saos-2 osteosarcoma cells. Transfection of sLRP5 caused a marked up-regulation of E-cadherin in this cell line. This increase in E-cadherin, seen primarily at the cell-cell contact borders, was associated with down-regulation of Slug and Twist, transcriptional repressors which mediate cancer invasion and metastasis. In contrast, N-cadherin, a mesenchymal marker, was reduced by sLRP5. In addition, blocking Wnt signaling by sLRP5 modulated other epithelial and mesenchymal markers (keratin 8 and 18, fibronectin), suggesting a reversal of epithelial-mesenchymal transition (EMT) seen during cancer progression. SLRP5 also reduced the expression of matrix metalloproteinase (MMP) 2 and 14, consistent with a decrease in invasive capacity. SLRP5 transfection decreased both Met expression and hepatocyte growth factor (HGF)-induced cell motility. Taken together, these results support a role for Wnt/LRP5 signaling in invasiveness of a subset of OS cells.
authors.affiliation: Department of Orthopaedic Surgery, University of California, Irvine, 101 The City Drive South, Orange, California 92868, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Guo
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zi
authors.forename: Zach
authors.initials: Z
authors.lastname: Koontz
authors.forename: Alison
authors.initials: A
authors.lastname: Kim
authors.forename: Jun
authors.initials: J
authors.lastname: Xie
authors.forename: Richard
authors.initials: R
authors.lastname: Gorlick
authors.forename: Randall F
authors.initials: RF
authors.lastname: Holcombe
authors.forename: Bang H
authors.initials: BH
authors.lastname: Hoang
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D001859:Bone Neoplasms / Q000473:pathology; D015820:Cadherins / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement; D002471:Cell Transformation, Neoplastic; D018450:Disease Progression; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D020868:Gene Silencing; D006801:Humans; D026502:LDL-Receptor Related Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D060492:Low Density Lipoprotein Receptor-Related Protein-5; D053511:Matrix Metalloproteinase 14; D020778:Matrix Metalloproteinase 2; D008648:Mesoderm / Q000378:metabolism* / Q000473:pathology; D045726:Metalloproteases / Q000235:genetics / Q000378:metabolism*; D010006:Osteoblasts / Q000378:metabolism* / Q000473:pathology; D012516:Osteosarcoma / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019859:Proto-Oncogene Proteins c-met; D017978:Receptors, Growth Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection; D051153:Wnt Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D026502:LDL-Receptor Related Proteins; C555482:LRP5 protein, human; D060492:Low Density Lipoprotein Receptor-Related Protein-5; D011518:Proto-Oncogene Proteins; D017978:Receptors, Growth Factor; D051153:Wnt Proteins; C491743:MET protein, human; D019859:Proto-Oncogene Proteins c-met; D045726:Metalloproteases; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14