Abstract
Osteosarcoma (OS) is a primary malignancy of bone with a tendency to metastasize early. Despite intensive chemotherapy and surgical resection, approximately 30% of patients still develop distant metastasis. Our previous work using clinical OS samples suggested that expression of the Wnt receptor LRP5 might be associated with tumor metastasis. In the present study, we used a Dickkopf (Dkk) family member and a dominant-negative LRP5 receptor construct to modulate Wnt signaling in OS cells. Saos-2 cells, which ectopically express Dkk-3, do not undergo apoptosis and exhibit enhanced resistance to serum starvation and chemotherapy-induced cytotoxicity. Transfection of Dkk-3 and dominant-negative LRP5 into Saos-2 cells significantly reduces invasion capacity and cell motility. This blockade is associated with changes in cell morphology consistent with a less invasive phenotype. In addition, Dkk-3 and dominant-negative LRP5 also induce changes in beta-catenin localization consistent with an increase in cell-cell adhesion. Taken together, these results support a possible role for Wnt signaling in the pathobiology and progression of human OS.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adaptor Proteins, Signal Transducing
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Bone Neoplasms / genetics
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Bone Neoplasms / metabolism
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Bone Neoplasms / pathology*
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Cell Line, Tumor
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Cell Movement / physiology*
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Chemokines
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Cytoplasm / metabolism
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Cytoskeletal Proteins / antagonists & inhibitors
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Cytoskeletal Proteins / metabolism
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Cytoskeletal Proteins / physiology*
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Humans
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Intercellular Signaling Peptides and Proteins
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LDL-Receptor Related Proteins
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Low Density Lipoprotein Receptor-Related Protein-5
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Neoplasm Invasiveness
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Osteosarcoma / genetics
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Osteosarcoma / metabolism
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Osteosarcoma / pathology*
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Protein Biosynthesis
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Proteins / genetics
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Proteins / physiology*
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins / physiology*
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Receptors, LDL / antagonists & inhibitors
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Receptors, LDL / biosynthesis
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Receptors, LDL / genetics
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Receptors, LDL / physiology
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Signal Transduction / physiology
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Trans-Activators / antagonists & inhibitors
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Trans-Activators / metabolism
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Trans-Activators / physiology*
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Transfection
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Wnt Proteins
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Zebrafish Proteins*
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beta Catenin
Substances
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Adaptor Proteins, Signal Transducing
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CTNNB1 protein, human
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Chemokines
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Cytoskeletal Proteins
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DKK3 protein, human
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Intercellular Signaling Peptides and Proteins
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LDL-Receptor Related Proteins
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LRP5 protein, human
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Low Density Lipoprotein Receptor-Related Protein-5
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Proteins
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Proto-Oncogene Proteins
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Receptors, LDL
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Trans-Activators
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Wnt Proteins
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Zebrafish Proteins
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beta Catenin