title: Wnt signaling in osteosarcoma.
abstract: Osteosarcoma (OS) is the most common primary bone malignancy diagnosed in children and adolescents with a high propensity for local invasion and distant metastasis. Despite current multidisciplinary treatments, there has not been a drastic change in overall prognosis within the last two decades. With current treatments, 60-70 % of patients with localized disease survive. Given a propensity of Wnt signaling to control multiple cellular processes, including proliferation, cell fate determination, and differentiation, it is a critical pathway in OS disease progression. At the same time, this pathway is extremely complex with vast arrays of cross-talk. Even though decades of research have linked the role of Wnt to tumorigenesis, there are still outstanding areas that remain poorly understood and even controversial. The canonical Wnt pathway functions to regulate the levels of the transcriptional co-activator β-catenin, which ultimately controls key developmental gene expressions. Given the central role of this mediator, inhibition of Wnt/β-catenin signaling has been investigated as a potential strategy for cancer control. In OS, several secreted protein families modulate the Wnt/β-catenin signaling, including secreted Frizzled-related proteins (sFRPs), Wnt inhibitory protein (WIF), Dickkopf proteins (DKK-1,2,3), sclerostin, and small molecules. This chapter focuses on our current understanding of Wnt/β-catenin signaling in OS, based on recent in vitro and in vivo data. Wnt activates noncanonical signaling pathways as well that are independent of β-catenin which will be discussed. In addition, stem cells and their association with Wnt/β-catenin are important factors to consider. Ultimately, the multiple canonical and noncanonical Wnt/β-catenin agonists and antagonists need to be further explored for potential targeted therapies.
authors.affiliation: The Hyundai Cancer Institute, CHOC Children's Hospital, Orange, CA, USA.
authors.forename: Carol H
authors.initials: CH
authors.lastname: Lin
authors.forename: Tao
authors.initials: T
authors.lastname: Ji
authors.forename: Cheng-Fong
authors.initials: CF
authors.lastname: Chen
authors.forename: Bang H
authors.initials: BH
authors.lastname: Hoang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000293:Adolescent; D000970:Antineoplastic Agents / Q000627:therapeutic use; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism; D001859:Bone Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002648:Child; D051157:Frizzled Receptors / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000556:secondary; D012516:Osteosarcoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000556:secondary; D015398:Signal Transduction / Q000187:drug effects*; D051153:Wnt Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D051176:beta Catenin / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D019485:Bone Morphogenetic Proteins; C501126:DKK1 protein, human; D051157:Frizzled Receptors; D005819:Genetic Markers; D036341:Intercellular Signaling Peptides and Proteins; C422903:SOST protein, human; D051153:Wnt Proteins; D051176:beta Catenin