Rubin EM, Guo Y, Tu K, Xie J, Zi X, Hoang BHWnt inhibitory factor 1 decreases tumorigenesis and metastasis in osteosarcoma. Mol Cancer Ther 9: 731-741

Department of Oncology, Children's Hospital of Orange County, Orange, California, USA.
Molecular Cancer Therapeutics (Impact Factor: 5.68). 03/2010; 9(3):731-41. DOI: 10.1158/1535-7163.MCT-09-0147
Source: PubMed


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.

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Available from: Xiaolin zi, Jan 02, 2014
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    • "The observed equivalent induction in Wif1 expression suggested similar epigenetic mechanisms may control Wif1 in OS cells and normal osteoblastic cells. WIF1 has been shown to be responsive to 5Aza in several human OS cell lines [13] [14], although its responsiveness to HDAC inhibition was not tested. The differential methylation of 4 CpG dinucleotides located 200 bp to 500 bp upstream from the transcription start site was proposed to mediate WIF1 silencing in human OS cells [13]. "
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    ABSTRACT: Wnt pathway targeting is of high clinical interest for treating bone loss disorders such as osteoporosis. These therapies inhibit the action of negative regulators of osteoblastic Wnt signaling. The report that Wnt inhibitory factor 1 (WIF1) was epigenetically silenced via promoter DNA methylation in osteosarcoma (OS) raised potential concerns for such treatment approaches. Here we confirm that Wif1 expression is frequently reduced in OS. However, we demonstrate that silencing is not driven by DNA methylation. Treatment of mouse and human OS cells showed that Wif1 expression was robustly induced by HDAC inhibition but not by methylation inhibition. Consistent with HDAC dependent silencing, the Wif1 locus in OS was characterized by low acetylation levels and a bivalent H3K4/H3K27-trimethylation state. Wif1 expression marked late stages of normal osteoblast maturation and stratified OS tumors based on differentiation stage across species. Culture of OS cells under differentiation inductive conditions increased expression of Wif1. Together these results demonstrate that Wif1 is not targeted for silencing by DNA methylation in OS. Instead, the reduced expression of Wif1 in OS cells is in context with their stage in differentiation. Copyright © 2014. Published by Elsevier Inc.
    Full-text · Article · Jan 2015 · Bone
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    • "Additionally, Wnt signaling can also be switched-on via crosstalk with other signaling pathways, including the phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway, which is frequently showed to be activated in sarcomas [22]–[24]. Consistent with a role in these tumors, reduction of in vitro and in vivo tumor growth and metastasis in osteosarcoma and fibrosarcoma respectively [25], [26] was achieved through ectopic expression of negative secreted modulators of the canonical Wnt pathway, such as of Wnt inhibitory factor 1 (WIF1) and the secreted Frizzled-related protein 3 (sFRP3; [27], [28]). β-catenin protein was found in the cytoplasm and nuclei of primary osteosarcoma cells [29], while, Wnt reporter activity was shown to be higher in various osteosarcoma cell lines compared with osteoblastic cells in the absence of exogenous Wnt stimulation [30]. "
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    ABSTRACT: Sarcomas are mesenchymal tumors showing high molecular heterogeneity, reflected at the histological level by the existence of more than fifty different subtypes. Genetic and epigenetic evidences link aberrant activation of the Wnt signaling to growth and progression of human sarcomas. This phenomenon, mainly accomplished by autocrine loop activity, is sustained by gene amplification, over-expression of Wnt ligands and co-receptors or epigenetic silencing of endogenous Wnt antagonists. We previously showed that pharmacological inhibition of Wnt signaling mediated by Axin stabilization produced in vitro and in vivo antitumor activity in glioblastoma tumors. Here, we report that targeting different sarcoma cell lines with the Wnt inhibitor/Axin stabilizer SEN461 produces a less transformed phenotype, as supported by modulation of anchorage-independent growth in vitro. At the molecular level, SEN461 treatment enhanced the stability of the scaffold protein Axin1, a key negative regulator of the Wnt signaling with tumor suppressor function, resulting in downstream effects coherent with inhibition of canonical Wnt signaling. Genetic phenocopy of small molecule Axin stabilization, through Axin1 over-expression, coherently resulted in strong impairment of soft-agar growth. Importantly, sarcoma growth inhibition through pharmacological Axin stabilization was also observed in a xenograft model in vivo in female CD-1 nude mice. Our findings suggest the usefulness of Wnt inhibitors with Axin stabilization activity as a potentialyl clinical relevant strategy for certain types of sarcomas.
    Full-text · Article · May 2014 · PLoS ONE
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    • "Indeed, elevated expression of the receptor LRP5 was observed in 50% of high-grade OS tumors and expression correlated with metastasis 29. Inhibition or loss of expression of the secreted inhibitor Wnt inhibitory factor (WIF1) was observed in 76% of OS patient samples in a different study 30,31. As elevated Wnt signaling is a common event in OS, inhibitors of Wnt/β-catenin may have therapeutic potential for OS patients 28. "
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    ABSTRACT: Wnt/β-catenin is a major regulator of stem cell self-renewal and differentiation and this signaling pathway is aberrantly activated in a several cancers, including osteosarcoma (OS). Attenuation of Wnt/β-catenin activity by tankyrase inhibitors is an appealing strategy in treatment of OS. The efficacy of the tankyrase inhibitor JW74 was evaluated in three OS cell lines (KPD, U2OS, and SaOS-2) both at the molecular and functional level. At the molecular level, JW74 induces stabilization of AXIN2, a key component of the β-catenin destruction complex, resulting in reduced levels of nuclear β-catenin. At the functional level, JW74 induces reduced cell growth in all three tested cell lines, in part due to a delay in cell cycle progression and in part due to an induction of caspase-3-mediated apoptosis. Furthermore, JW74 induces differentiation in U2OS cells, which under standard conditions are resistant to osteogenic differentiation. JW74 also enhances differentiation of OS cell lines, which do not harbor a differentiation block. Interestingly, microRNAs (miRNAs) of the let-7 family, which are known tumor suppressors and inducers of differentiation, are significantly upregulated following treatment with JW74. We demonstrate for the first time that tankyrase inhibition triggers reduced cell growth and differentiation of OS cells. This may in part be due to an induction of let-7 miRNA. The presented data open for novel therapeutic strategies in the treatment of malignant OS.
    Full-text · Article · Feb 2014 · Cancer Medicine
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