title: Wnt inhibitory factor 1 decreases tumorigenesis and metastasis in osteosarcoma.
abstract: It has been reported that the progression of osteosarcoma was closely associated with the aberrant activation of canonical Wnt signaling. Wnt inhibitory factor-1 (WIF-1) is a secreted Wnt inhibitor whose role in human osteosarcoma remains unknown. In this study, WIF-1 expression in NHOst and osteosarcoma cell lines was determined by real-time reverse transcription-PCR, methylation-specific PCR, and Western blotting analysis. In addition, tissue array from patient samples was examined for WIF-1 expression by immunohistochemistry. Compared with normal human osteoblasts, WIF-1 mRNA and protein levels were significantly downregulated in several osteosarcoma cell lines. The downregulation of WIF-1 mRNA expression is associated with its promoter hypermethylation in these tested cell lines. Importantly, WIF-1 expression was also downregulated in 76% of examined osteosarcoma cases. These results suggest that the downregulation of WIF-1 expression plays a role in osteosarcoma progression. To further study the potential tumor suppressor function of WIF-1 in osteosarcoma, we established stable 143B cell lines overexpressing WIF-1. WIF-1 overexpression significantly decreased tumor growth rate in nude mice as examined by the s.c. injection of 143B cells stably transfected with WIF-1 and vector control. WIF-1 overexpression also markedly reduced the number of lung metastasis in vivo in an orthotopic mouse model of osteosarcoma. Together, these data suggest that WIF-1 exerts potent antiosteosarcoma effect in vivo in mouse models. Therefore, the reexpression of WIF-1 in WIF-1-deficient osteosarcoma represents a potential novel treatment and preventive strategy.
authors.affiliation: Department of Oncology, Children's Hospital of Orange County, Orange, California, USA.
authors.forename: Elyssa M
authors.initials: EM
authors.lastname: Rubin
authors.forename: Yi
authors.initials: Y
authors.lastname: Guo
authors.forename: Khoa
authors.initials: K
authors.lastname: Tu
authors.forename: Jun
authors.initials: J
authors.lastname: Xie
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zi
authors.forename: Bang H
authors.initials: BH
authors.lastname: Hoang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000502:physiology*; D000818:Animals; D001859:Bone Neoplasms / Q000235:genetics* / Q000473:pathology*; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D019175:DNA Methylation; D015536:Down-Regulation / Q000235:genetics / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D012516:Osteosarcoma / Q000235:genetics* / Q000473:pathology*; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D012097:Repressor Proteins; C485569:WIF1 protein, human