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Zhang J, Liu G, Liu Y, Yang P, Xie J, Wei X. The biological functions and related signaling pathways of SPON2. Front Oncol 2024; 13:1323744. [PMID: 38264743 PMCID: PMC10803442 DOI: 10.3389/fonc.2023.1323744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/20/2023] [Indexed: 01/25/2024] Open
Abstract
Spondin-2 (SPON2), also referred to as M-spondin or DIL-1, is a member of the extracellular matrix protein family known as Mindin-F-spondin (FS). SPON2 can be used as a broad-spectrum tumor marker for more than a dozen tumors, mainly prostate cancer. Meanwhile, SPON2 is also a potential biomarker for the diagnosis of certain non-tumor diseases. Additionally, SPON2 plays a pivotal role in regulating tumor metastasis and progression. In normal tissues, SPON2 has a variety of biological functions represented by promoting growth and development and cell proliferation. This paper presents a comprehensive overview of the regulatory mechanisms, diagnostic potential as a broad-spectrum biomarker, diverse biological functions, involvement in various signaling pathways, and clinical applications of SPON2.
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Affiliation(s)
- Jingrun Zhang
- Zhongshan Clinical College, Dalian University, Dalian, China
- Laboratory of Orthopedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Ge Liu
- Laboratory of Orthopedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Yuchen Liu
- Zhongshan Clinical College, Dalian University, Dalian, China
| | - Pei Yang
- Department of Neurology, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Junyuan Xie
- Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaowei Wei
- Laboratory of Orthopedics, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
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Zheng C, Zhou F, Shi LL, Xu GF, Zhang B, Wang L, Zhuge Y, Zou XP, Wang Y. R-spondin2 Suppresses the Progression of Hepatocellular Carcinoma via MAPK Signaling Pathway. Mol Cancer Res 2020; 18:1491-1499. [PMID: 32581137 DOI: 10.1158/1541-7786.mcr-19-0599] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 02/19/2020] [Accepted: 06/19/2020] [Indexed: 11/16/2022]
Affiliation(s)
- Chang Zheng
- Department of Gastroenterology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Fan Zhou
- Department of Gastroenterology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Liang Liang Shi
- Department of Gastroenterology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Gui Fang Xu
- Department of Gastroenterology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Bin Zhang
- Department of Gastroenterology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Lei Wang
- Department of Gastroenterology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Yuzheng Zhuge
- Department of Gastroenterology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Xiao Ping Zou
- Department of Gastroenterology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Yi Wang
- Department of Gastroenterology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China.
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Phenotypic and Molecular Alterations in the Mammary Tissue of R-Spondin1 Knock-Out Mice during Pregnancy. PLoS One 2016; 11:e0162566. [PMID: 27611670 PMCID: PMC5017653 DOI: 10.1371/journal.pone.0162566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/24/2016] [Indexed: 02/05/2023] Open
Abstract
R-spondin1 (Rspo1) is a member of a secreted protein family which has pleiotropic functions in development and stem cell growth. Rspo1 knock-out mice are sex-reversed, but some remain sub-fertile, so they fail to nurse their pups. A lack of Rspo1 expression in the mammary gland results in an absence of duct side-branching development and defective alveolar formation. The aim of this study was to characterize the phenotypic and molecular alterations of mammary gland due to Rspo1 knock-out. Using the transcriptional profiling of mammary tissues, we identified misregulated genes in the mammary gland of Rspo1 knock-out mice during pregnancy. A stronger expression of mesenchymal markers was observed, without modifications to the structure of mammary epithelial tissue. Mammary epithelial cell immunohistochemical analysis revealed a persistence of virgin markers, which signify a delay in cell differentiation. Moreover, serial transplantation experiments showed that Rspo1 is associated with a regenerative potential of mammary epithelial cell control. Our finding also highlights the negatively regulated expression of Rspo1’s partners, Lgr4 and RNF43, in the mammary gland during pregnancy. Moreover, we offer evidence that Tgf-β signalling is modified in the absence of Rspo1. Taken together, our results show an abrupt halt or delay to mammary development during pregnancy due to the loss of a further differentiated function.
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Maubant S, Tesson B, Maire V, Ye M, Rigaill G, Gentien D, Cruzalegui F, Tucker GC, Roman-Roman S, Dubois T. Transcriptome analysis of Wnt3a-treated triple-negative breast cancer cells. PLoS One 2015; 10:e0122333. [PMID: 25848952 PMCID: PMC4388387 DOI: 10.1371/journal.pone.0122333] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 02/10/2015] [Indexed: 12/31/2022] Open
Abstract
The canonical Wnt/β-catenin pathway is activated in triple-negative breast cancer (TNBC). The activation of this pathway leads to the expression of specific target genes depending on the cell/tissue context. Here, we analyzed the transcriptome of two different TNBC cell lines to define a comprehensive list of Wnt target genes. The treatment of cells with Wnt3a for 6h up-regulated the expression (fold change > 1.3) of 59 genes in MDA-MB-468 cells and 241 genes in HCC38 cells. Thirty genes were common to both cell lines. Beta-catenin may also be a transcriptional repressor and we found that 18 and 166 genes were down-regulated in response to Wnt3a treatment for 6h in MDA-MB-468 and HCC38 cells, respectively, of which six were common to both cell lines. Only half of the activated and the repressed transcripts have been previously described as Wnt target genes. Therefore, our study reveals 137 novel genes that may be positively regulated by Wnt3a and 104 novel genes that may be negatively regulated by Wnt3a. These genes are involved in the Wnt pathway itself, and also in TGFβ, p53 and Hedgehog pathways. Thorough characterization of these novel potential Wnt target genes may reveal new regulators of the canonical Wnt pathway. The comparison of our list of Wnt target genes with those published in other cellular contexts confirms the notion that Wnt target genes are tissue-, cell line- and treatment-specific. Genes up-regulated in Wnt3a-stimulated cell lines were more strongly expressed in TNBC than in luminal A breast cancer samples. These genes were also overexpressed, but to a much lesser extent, in HER2+ and luminal B tumors. We identified 72 Wnt target genes higher expressed in TNBCs (17 with a fold change >1.3) which may reflect the chronic activation of the canonical Wnt pathway that occurs in TNBC tumors.
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Affiliation(s)
- Sylvie Maubant
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Bruno Tesson
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
- INSERM U900, Bioinformatics, Biostatistics, Epidemiology and Computational Systems Biology of Cancer, Institut Curie, Centre de Recherche, Paris, France
- Mines ParisTech, Fontainebleau, France
| | - Virginie Maire
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Mengliang Ye
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Guillem Rigaill
- Unité de Recherche en Génomique Végétale, INRA-CNRS-Université d'Evry Val d'Essonne, Evry, France
| | - David Gentien
- Platform of Molecular Biology Facilities, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Francisco Cruzalegui
- Institut de Recherches SERVIER, Pôle Innovation Thérapeutique Oncologie, Croissy-sur-Seine, France
| | - Gordon C. Tucker
- Institut de Recherches SERVIER, Pôle Innovation Thérapeutique Oncologie, Croissy-sur-Seine, France
| | - Sergio Roman-Roman
- Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
| | - Thierry Dubois
- Breast Cancer Biology Group, Translational Research Department, Institut Curie, Centre de Recherche, Paris, France
- * E-mail:
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Schneider AJ, Branam AM, Peterson RE. Intersection of AHR and Wnt signaling in development, health, and disease. Int J Mol Sci 2014; 15:17852-85. [PMID: 25286307 PMCID: PMC4227194 DOI: 10.3390/ijms151017852] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/04/2014] [Accepted: 09/18/2014] [Indexed: 12/16/2022] Open
Abstract
The AHR (aryl hydrocarbon receptor) and Wnt (wingless-related MMTV integration site) signaling pathways have been conserved throughout evolution. Appropriately regulated signaling through each pathway is necessary for normal development and health, while dysregulation can lead to developmental defects and disease. Though both pathways have been vigorously studied, there is relatively little research exploring the possibility of crosstalk between these pathways. In this review, we provide a brief background on (1) the roles of both AHR and Wnt signaling in development and disease, and (2) the molecular mechanisms that characterize activation of each pathway. We also discuss the need for careful and complete experimental evaluation of each pathway and describe existing research that explores the intersection of AHR and Wnt signaling. Lastly, to illustrate in detail the intersection of AHR and Wnt signaling, we summarize our recent findings which show that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced disruption of Wnt signaling impairs fetal prostate development.
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Affiliation(s)
- Andrew J Schneider
- School of Pharmacy and Molecular and Environmental Toxicology Center University of Wisconsin, Madison, WI 53705, USA.
| | - Amanda M Branam
- School of Pharmacy and Molecular and Environmental Toxicology Center University of Wisconsin, Madison, WI 53705, USA.
| | - Richard E Peterson
- School of Pharmacy and Molecular and Environmental Toxicology Center University of Wisconsin, Madison, WI 53705, USA.
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Cambier L, Plate M, Sucov HM, Pashmforoush M. Nkx2-5 regulates cardiac growth through modulation of Wnt signaling by R-spondin3. Development 2014; 141:2959-71. [PMID: 25053429 DOI: 10.1242/dev.103416] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A complex regulatory network of morphogens and transcription factors is essential for normal cardiac development. Nkx2-5 is among the earliest known markers of cardiac mesoderm that is central to the regulatory pathways mediating second heart field (SHF) development. Here, we have examined the specific requirements for Nkx2-5 in the SHF progenitors. We show that Nkx2-5 potentiates Wnt signaling by regulating the expression of the R-spondin3 (Rspo3) gene during cardiogenesis. R-spondins are secreted factors and potent Wnt agonists that in part regulate stem cell proliferation. Our data show that Rspo3 is markedly downregulated in Nkx2-5 mutants and that Rspo3 expression is regulated by Nkx2-5. Conditional inactivation of Rspo3 in the Isl1 lineage resulted in embryonic lethality secondary to impaired development of SHF. More importantly, we find that Wnt signaling is significantly attenuated in Nkx2-5 mutants and that enhancing Wnt/β-catenin signaling by pharmacological treatment or by transgenic expression of Rspo3 rescues the SHF defects in the conditional Nkx2-5(+/-) mutants. We have identified a previously unrecognized genetic link between Nkx2-5 and Wnt signaling that supports continued cardiac growth and proliferation during development. Identification of Rspo3 in cardiac development provides a new paradigm in temporal regulation of Wnt signaling by cardiac-specific transcription factors.
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Affiliation(s)
- Linda Cambier
- Broad Center for Regenerative Medicine and Stem Cell Research, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Markus Plate
- Broad Center for Regenerative Medicine and Stem Cell Research, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Henry M Sucov
- Broad Center for Regenerative Medicine and Stem Cell Research, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Mohammad Pashmforoush
- Broad Center for Regenerative Medicine and Stem Cell Research, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA
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Both canonical and non-canonical Wnt signaling independently promote stem cell growth in mammospheres. PLoS One 2014; 9:e101800. [PMID: 25019931 PMCID: PMC4096729 DOI: 10.1371/journal.pone.0101800] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 06/11/2014] [Indexed: 02/06/2023] Open
Abstract
The characterization of mammary stem cells, and signals that regulate their behavior, is of central importance in understanding developmental changes in the mammary gland and possibly for targeting stem-like cells in breast cancer. The canonical Wnt/β-catenin pathway is a signaling mechanism associated with maintenance of self-renewing stem cells in many tissues, including mammary epithelium, and can be oncogenic when deregulated. Wnt1 and Wnt3a are examples of ligands that activate the canonical pathway. Other Wnt ligands, such as Wnt5a, typically signal via non-canonical, β-catenin-independent, pathways that in some cases can antagonize canonical signaling. Since the role of non-canonical Wnt signaling in stem cell regulation is not well characterized, we set out to investigate this using mammosphere formation assays that reflect and quantify stem cell properties. Ex vivo mammosphere cultures were established from both wild-type and Wnt1 transgenic mice and were analyzed in response to manipulation of both canonical and non-canonical Wnt signaling. An increased level of mammosphere formation was observed in cultures derived from MMTV-Wnt1 versus wild-type animals, and this was blocked by treatment with Dkk1, a selective inhibitor of canonical Wnt signaling. Consistent with this, we found that a single dose of recombinant Wnt3a was sufficient to increase mammosphere formation in wild-type cultures. Surprisingly, we found that Wnt5a also increased mammosphere formation in these assays. We confirmed that this was not caused by an increase in canonical Wnt/β-catenin signaling but was instead mediated by non-canonical Wnt signals requiring the receptor tyrosine kinase Ror2 and activity of the Jun N-terminal kinase, JNK. We conclude that both canonical and non-canonical Wnt signals have positive effects promoting stem cell activity in mammosphere assays and that they do so via independent signaling mechanisms.
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Schneider BG, Piazuelo MB, Sicinschi LA, Mera R, Peng DF, Roa JC, Romero-Gallo J, Delgado AG, de Sablet T, Bravo LE, Wilson KT, El-Rifai W, Peek Jr RM, Correa P. Virulence of infecting Helicobacter pylori strains and intensity of mononuclear cell infiltration are associated with levels of DNA hypermethylation in gastric mucosae. Epigenetics 2013; 8:1153-61. [PMID: 24128875 PMCID: PMC3927747 DOI: 10.4161/epi.26072] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 08/01/2013] [Accepted: 08/07/2013] [Indexed: 12/27/2022] Open
Abstract
DNA methylation changes are known to occur in gastric cancers and in premalignant lesions of the gastric mucosae. In order to examine variables associated with methylation levels, we quantitatively evaluated DNA methylation in tumors, non-tumor gastric mucosae, and in gastric biopsies at promoters of 5 genes with methylation alterations that discriminate gastric cancers from non-tumor epithelia (EN1, PCDH10, RSPO2, ZIC1, and ZNF610). Among Colombian subjects at high and low risk for gastric cancer, biopsies from subjects from the high-risk region had significantly higher levels of methylation at these 5 genes than samples from subjects in the low risk region (p ≤ 0.003). When results were stratified by Helicobacter pylori infection status, infection with a cagA positive, vacA s1m1 strain was significantly associated with highest methylation levels, compared with other strains (p = 0.024 to 0.001). More severe gastric inflammation and more advanced precancerous lesions were also associated with higher levels of DNA methylation (p ≤ 0.001). In a multivariate model, location of residence of the subject and the presence of cagA and vacA s1m1 in the H. pylori strain were independent variables associated with higher methylation in all 5 genes. High levels of mononuclear cell infiltration were significantly related to methylation in PCDH10, RSPO2, and ZIC1 genes. These results indicate that for these genes, levels of methylation in precancerous lesions are related to H. pylori virulence, geographic region and measures of chronic inflammation. These genes seem predisposed to sustain significant quantitative changes in DNA methylation at early stages of the gastric precancerous process.
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Affiliation(s)
- Barbara G Schneider
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
| | - M Blanca Piazuelo
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
| | - Liviu A Sicinschi
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
- Holmes Regional Medical Center; Melbourne, FL USA
| | - Robertino Mera
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
| | - Dun-Fa Peng
- Department of Surgery; Vanderbilt University Medical Center; Nashville, TN USA
| | - Juan Carlos Roa
- Department of Pathology; School of Medicine; Pontificia Universidad Catolica de Chile; Santiago, Chile
| | - Judith Romero-Gallo
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
| | - Alberto G Delgado
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
| | - Thibaut de Sablet
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
| | - Luis E Bravo
- Department of Pathology; School of Medicine; Universidad del Valle; Cali, Colombia
| | - Keith T Wilson
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
- Veterans Affairs Tennessee Valley Healthcare System and Office of Medical Research; Department of Veterans Affairs; Nashville, TN USA
| | - Wael El-Rifai
- Department of Surgery; Vanderbilt University Medical Center; Nashville, TN USA
- Veterans Affairs Tennessee Valley Healthcare System and Office of Medical Research; Department of Veterans Affairs; Nashville, TN USA
| | - Richard M Peek Jr
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
| | - Pelayo Correa
- Division of Gastroenterology; Department of Medicine; Vanderbilt University Medical Center; Nashville, TN USA
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Xavier CP, Melikova M, Chuman Y, Üren A, Baljinnyam B, Rubin JS. Secreted Frizzled-related protein potentiation versus inhibition of Wnt3a/β-catenin signaling. Cell Signal 2013; 26:94-101. [PMID: 24080158 DOI: 10.1016/j.cellsig.2013.09.016] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 09/18/2013] [Accepted: 09/23/2013] [Indexed: 01/22/2023]
Abstract
Wnt signaling regulates a variety of cellular processes during embryonic development and in the adult. Many of these activities are mediated by the Frizzled family of seven-pass transmembrane receptors, which bind Wnts via a conserved cysteine-rich domain (CRD). Secreted Frizzled-related proteins (sFRPs) contain an amino-terminal, Frizzled-like CRD and a carboxyl-terminal, heparin-binding netrin-like domain. Previous studies identified sFRPs as soluble Wnt antagonists that bind directly to Wnts and prevent their interaction with Frizzleds. However, subsequent observations suggested that sFRPs and Frizzleds form homodimers and heterodimers via their respective CRDs, and that sFRPs can stimulate signal transduction. Here, we present evidence that sFRP1 either inhibits or enhances signaling in the Wnt3a/β-catenin pathway, depending on its concentration and the cellular context. Nanomolar concentrations of sFRP1 increased Wnt3a signaling, while higher concentrations blocked it in HEK293 cells expressing a SuperTopFlash reporter. sFRP1 primarily augmented Wnt3a/β-catenin signaling in C57MG cells, but it behaved as an antagonist in L929 fibroblasts. sFRP1 enhanced reporter activity in L cells that were engineered to stably express Frizzled 5, though not Frizzled 2. This implied that the Frizzled expression pattern could determine the response to sFRP1. Similar results were obtained with sFRP2 in HEK293, C57MG and L cell reporter assays. CRDsFRP1 mimicked the potentiating effect of sFRP1 in multiple settings, contradicting initial expectations that this domain would inhibit Wnt signaling. Moreover, CRDsFRP1 showed little avidity for Wnt3a compared to sFRP1, implying that the mechanism for potentiation by CRDsFRP1 probably does not require an interaction with Wnt protein. Together, these findings demonstrate that sFRPs can either promote or suppress Wnt/β-catenin signaling, depending on cellular context, concentration and most likely the expression pattern of Fzd receptors.
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Affiliation(s)
- Charles P Xavier
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, Bethesda, MD 20892, United States
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Gene expression profiling of a hypoxic seizure model of epilepsy suggests a role for mTOR and Wnt signaling in epileptogenesis. PLoS One 2013; 8:e74428. [PMID: 24086344 PMCID: PMC3785482 DOI: 10.1371/journal.pone.0074428] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 08/01/2013] [Indexed: 01/09/2023] Open
Abstract
Microarray profiling was used to investigate gene expression in the hypoxic seizure model of acquired epilepsy in the rat, with the aim of characterizing functional pathways which are persistently activated or repressed during epileptogenesis. Hippocampal and cortical tissues were transcriptionally profiled over a one week period following an initial series of seizures induced by mild hypoxia at post-natal day 10 (P10), and the gene expression data was then analyzed with a focus on gene set enrichment analysis, an approach which emphasizes regulation of entire pathways rather than of individual genes. Animals were subjected to one of three conditions: a control with no hypoxia, hypoxic seizures, and hypoxic seizures followed by treatment with the AMPAR antagonist NBQX, a compound currently proposed to be a modulator of epileptogenesis. While temporal gene expression in the control samples was found to be consistent with known processes of neuronal maturation in the rat for the given time window, the hypoxic seizure response was found to be enriched for components of the PI3K/mTOR and Wnt signaling pathways, alongside gene sets representative of glutamatergic, synaptic and axonal processes, perhaps regulated as a downstream consequence of activation of these pathways. Wnt signaling components were also found enriched in the more specifically epileptogenic NBQX-responsive gene set. While activation of the mTOR pathway is consistent with its known role in epileptogenesis and strengthens the case for mTOR or PI3K pathway inhibitors as potential anti-epileptogenic drugs, investigation of the role of Wnt signaling and the effect of appropriate inhibitors might offer a parallel avenue of research toward anti-epileptogenic treatment of epilepsy.
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11
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González-Sancho JM, Greer YE, Abrahams CL, Takigawa Y, Baljinnyam B, Lee KH, Lee KS, Rubin JS, Brown AMC. Functional consequences of Wnt-induced dishevelled 2 phosphorylation in canonical and noncanonical Wnt signaling. J Biol Chem 2013; 288:9428-37. [PMID: 23396967 DOI: 10.1074/jbc.m112.448480] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Dishevelled (Dvl) proteins are intracellular effectors of Wnt signaling that have essential roles in both canonical and noncanonical Wnt pathways. It has long been known that Wnts stimulate Dvl phosphorylation, but relatively little is known about its functional significance. We have previously reported that both Wnt3a and Wnt5a induce Dvl2 phosphorylation that is associated with an electrophoretic mobility shift and loss of recognition by monoclonal antibody 10B5. In the present study, we mapped the 10B5 epitope to a 16-amino acid segment of human Dvl2 (residues 594-609) that contains four Ser/Thr residues. Alanine substitution of these residues (P4m) eliminated the mobility shift induced by either Wnt3a or Wnt5a. The Dvl2 P4m mutant showed a modest increase in canonical Wnt/β-catenin signaling activity relative to wild type. Consistent with this finding, Dvl2 4Pm preferentially localized to cytoplasmic puncta. In contrast to wild-type Dvl2, however, the P4m mutant was unable to rescue Wnt3a-dependent neurite outgrowth in TC-32 cells following suppression of endogenous Dvl2/3. Earlier work has implicated casein kinase 1δ/ε as responsible for the Dvl mobility shift, and a CK1δ in vitro kinase assay confirmed that Ser(594), Thr(595), and Ser(597) of Dvl2 are CK1 targets. Alanine substitution of these three residues was sufficient to abrogate the Wnt-dependent mobility shift. Thus, we have identified a cluster of Ser/Thr residues in the C-terminal domain of Dvl2 that are Wnt-induced phosphorylation (WIP) sites. Our results indicate that phosphorylation at the WIP sites reduces Dvl accumulation in puncta and attenuates β-catenin signaling, whereas it enables noncanonical signaling that is required for neurite outgrowth.
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Affiliation(s)
- José M González-Sancho
- Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY 10065, USA
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Gauger KJ, Shimono A, Crisi GM, Schneider SS. Loss of SFRP1 promotes ductal branching in the murine mammary gland. BMC DEVELOPMENTAL BIOLOGY 2012; 12:25. [PMID: 22928951 PMCID: PMC3482146 DOI: 10.1186/1471-213x-12-25] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 08/13/2012] [Indexed: 01/22/2023]
Abstract
BACKGROUND Secreted frizzled-related proteins (SFRPs) are a family of proteins that block the Wnt signaling pathway and loss of SFRP1 expression is found in breast cancer along with a multitude of other human cancers. Activated Wnt signaling leads to inappropriate mammary gland development and mammary tumorigenesis in mice. When SFRP1 is knocked down in immortalized non-malignant mammary epithelial cells, the cells exhibit a malignant phenotype which resembles the characteristics observed in metastatic breast cancer stem-like cells. However, the effects of SFRP1 loss on mammary gland development in vivo are yet to be elucidated. The work described here was initiated to investigate the role of SFRP1 in mammary gland development and whether SFRP1-/- mice exhibit changes in mammary gland morphology and cell signaling pathways shown to be associated with SFRP1 loss in vitro. RESULTS 10 week old nulliparous SFRP1-/- mammary glands exhibited branching with clear lobulo-alveolar development, which normally only occurs in hormonally stimulated mid-pregnant wt mammary glands. Explant cultures of SFRP1-/- mammary glands display increased levels of a well known Wnt signaling target gene, Axin2. Histomorphologic evaluation of virgin glands revealed that by 10 weeks of age, the duct profile is markedly altered in SFRP1-/- mice showing a significantly higher density of ducts with distinct alveoli present throughout the mammary gland, and with focal ductal epithelial hyperplasia. These findings persist as the mice age and are evident at 23 weeks of age. Changes in gene expression, including c-Myc, TGFβ-2, Wnt4, RANKL, and Rspo2 early in mammary gland development are consistent with the excessive hyper branching phenotype. Finally, we found that loss of SFRP1 significantly increases the number of mammary epithelial cells capable of mammosphere formation. CONCLUSIONS Our study indicates that SFRP1 gene is critical for maintaining proper mammary gland development, and that reduced levels of SFRP1 results in hyperplastic lesions and its loss may be a critical event in cancer initiation.
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Affiliation(s)
- Kelly J Gauger
- Pioneer Valley Life Sciences Institute, Baystate Medical Center, Springfield, MA 01199, USA.
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