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GPNMB augments Wnt-1 mediated breast tumor initiation and growth by enhancing PI3K/AKT/mTOR pathway signaling and β-catenin activity. Oncogene 2019; 38:5294-5307. [PMID: 30914799 DOI: 10.1038/s41388-019-0793-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 03/10/2019] [Accepted: 03/11/2019] [Indexed: 01/08/2023]
Abstract
Glycoprotein Nmb (GPNMB) is overexpressed in triple-negative and basal-like breast cancers and its expression is predictive of poor prognosis within this aggressive breast cancer subtype. GPNMB promotes breast cancer growth, invasion, and metastasis; however, its role in mammary tumor initiation remains unknown. To address this question, we overexpressed GPNMB in the mammary epithelium to generate MMTV/GPNMB transgenic mice and crossed these animals to the MMTV/Wnt-1 mouse model, which is known to recapitulate features of human basal breast cancers. We show that GPNMB alone does not display oncogenic properties; however, its expression dramatically accelerates tumor onset in MMTV/Wnt-1 mice. MMTV/Wnt-1 × MMTV/GPNMB bigenic mice also exhibit a significant increase in the growth rate of established primary tumors, which is attributable to increased proliferation and decreased apoptosis. To elucidate molecular mechanisms underpinning the tumor-promoting effects of GPNMB in this context, we interrogated activated pathways in tumors derived from the MMTV/Wnt-1 and MMTV/Wnt-1 × MMTV/GPNMB mice using RPPA analysis. These data revealed that MMTV/Wnt-1 × MMTV/GPNMB bigenic tumors exhibit a pro-growth signature characterized by elevated PI3K/AKT/mTOR signaling and increased β-catenin activity. Furthermore, we extended these observations to an independent Wnt-1 expressing model of aggressive breast cancer, and confirmed that GPNMB enhances canonical Wnt pathway activation, as evidenced by increased β-catenin transcriptional activity, in breast cancer cells and tumors co-expressing Wnt-1 and GPNMB. GPNMB-dependent engagement of β-catenin occurred, in part, through AKT activation. Taken together, these data ascribe a novel, pro-growth role for GPNMB in Wnt-1 expressing basal breast cancers.
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TGF- α Overexpression in Breast Cancer Bone Metastasis and Primary Lesions and TGF- α Enhancement of Expression of Procancer Metastasis Cytokines in Bone Marrow Mesenchymal Stem Cells. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6565393. [PMID: 29581982 PMCID: PMC5822790 DOI: 10.1155/2018/6565393] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 11/29/2017] [Accepted: 12/27/2017] [Indexed: 02/07/2023]
Abstract
Bone metastasis (BM) is the advanced complication of breast cancer, while bone marrow-derived mesenchymal stem cells (BMSCs) in the microenvironment unclearly contribute to cancer metastasis. This study investigated potential roles of transforming growth factor- (TGF-) α in the interaction between breast cancer and BMSCs in BM. Clinical cases of breast cancer with bone metastasis (BMBC), breast cancer without bone metastasis (Non-BM-BC), and benign fibroadenoma (Benign) were enlisted in a retrospective study. TGF-α was found obviously overexpressed in BM lesion of BMBC compared to primary lesion of both BMBC and Non-BM-BC (P < 0.01), and TGF-α was higher in primary lesion of both BMBC and Non-BM-BC (P < 0.01) than Benign group. Interestingly, TGF-α in nontumor tissues of both BMBC and Non-BM-BC was at a higher level than Benign group (P < 0.01), and numbers of macrophages in nontumor tissues of both BMBC and Non-BM-BC (P < 0.01) were higher than Benign group. Furthermore, in cultured human BMSCs, TGF-α stimulated production of procancer cytokines including IL-6, VEGF, FGF10, FGF17, and TGF-β1 in a dose-dependent manner. Thus, TGF-α in BC could potentially be an important signal of carcinogenesis and metastasis. Macrophages in the nontumor tissue of BC may not be protective but could promote cancer metastasis.
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Botting GM, Rastogi I, Chhabra G, Nlend M, Puri N. Mechanism of Resistance and Novel Targets Mediating Resistance to EGFR and c-Met Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancer. PLoS One 2015; 10:e0136155. [PMID: 26301867 PMCID: PMC4547756 DOI: 10.1371/journal.pone.0136155] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 07/31/2015] [Indexed: 12/26/2022] Open
Abstract
Tyrosine kinase inhibitors (TKIs) against EGFR and c-Met are initially effective when administered individually or in combination to non-small cell lung cancer (NSCLC) patients. However, the overall efficacies of TKIs are limited due to the development of drug resistance. Therefore, it is important to elucidate mechanisms of EGFR and c-Met TKI resistance in order to develop more effective therapies. Model NSCLC cell lines H1975 and H2170 were used to study the similarities and differences in mechanisms of EGFR/c-Met TKI resistance. H1975 cells are positive for the T790M EGFR mutation, which confers resistance to current EGFR TKI therapies, while H2170 cells are EGFR wild-type. Previously, H2170 cells were made resistant to the EGFR TKI erlotinib and the c-Met TKI SU11274 by exposure to progressively increasing concentrations of TKIs. In H2170 and H1975 TKI-resistant cells, key Wnt and mTOR proteins were found to be differentially modulated. Wnt signaling transducer, active β-catenin was upregulated in TKI-resistant H2170 cells when compared to parental cells. GATA-6, a transcriptional activator of Wnt, was also found to be upregulated in resistant H2170 cells. In H2170 erlotinib resistant cells, upregulation of inactive GSK3β (p-GSK3β) was observed, indicating activation of Wnt and mTOR pathways which are otherwise inhibited by its active form. However, in H1975 cells, Wnt modulators such as active β-catenin, GATA-6 and p-GSK3β were downregulated. Additional results from MTT cell viability assays demonstrated that H1975 cell proliferation was not significantly decreased after Wnt inhibition by XAV939, but combination treatment with everolimus (mTOR inhibitor) and erlotinib resulted in synergistic cell growth inhibition. Thus, in H2170 cells and H1975 cells, simultaneous inhibition of key Wnt or mTOR pathway proteins in addition to EGFR and c-Met may be a promising strategy for overcoming EGFR and c-Met TKI resistance in NSCLC patients.
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Affiliation(s)
- Gregory M. Botting
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America
| | - Ichwaku Rastogi
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America
| | - Gagan Chhabra
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America
| | - Marie Nlend
- Thermo Fisher Scientific, Rockford, Illinois, United States of America
| | - Neelu Puri
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America
- * E-mail:
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Ross SR. Mouse mammary tumor virus molecular biology and oncogenesis. Viruses 2010; 2:2000-2012. [PMID: 21274409 PMCID: PMC3026287 DOI: 10.3390/v2092000] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/25/2010] [Accepted: 09/15/2010] [Indexed: 01/15/2023] Open
Abstract
Mouse mammary tumor virus (MMTV), which was discovered as a milk-transmitted, infectious cancer-inducing agent in the 1930s, has been used since that time as an animal model for the study of human breast cancer. Like other complex retroviruses, MMTV encodes a number of accessory proteins that both facilitate infection and affect host immune response. In vivo, the virus predominantly infects lymphocytes and mammary epithelial cells. High level infection of mammary epithelial cells ensures efficient passage of virus to the next generation. It also results in mammary tumor induction, since the MMTV provirus integrates into the mammary epithelial cell genome during viral replication and activates cellular oncogene expression. Thus, mammary tumor induction is a by-product of the infection cycle. A number of important oncogenes have been discovered by carrying out MMTV integration site analysis, some of which may play a role in human breast cancer.
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Affiliation(s)
- Susan R Ross
- Department of Microbiology and Abramson Cancer Center, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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Zhu H, Zhang G, Wang Y, Xu N, He S, Zhang W, Chen M, Liu M, Quan L, Bai J, Xu N. Inhibition of ErbB2 by Herceptin reduces survivin expression via the ErbB2-beta-catenin/TCF4-survivin pathway in ErbB2-overexpressed breast cancer cells. Cancer Sci 2010; 101:1156-62. [PMID: 20331626 PMCID: PMC11158864 DOI: 10.1111/j.1349-7006.2010.01528.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Overexpression of ErbB2 is associated with poor prognosis in breast cancer. Targeting of ErbB2 is a very common therapeutic strategy in ErbB2-overexpressed breast cancer. Herceptin is the first approved and most widely used agent for ErbB2-targeting therapy in breast cancer. Even though the clinical application has been performed for more than 10 years, the exact mechanism underlying how Herceptin exhibits its effects has not been fully elucidated. In this study, we found that Herceptin could inhibit the expression of survivin in ErbB2-overexpressed cell lines. Overexpression of survivin could abrogate the inhibition of cell growth induced by Herceptin. Herceptin could reduce survivin expression at the transcriptional level. The beta-catenin/T-cell factor (TCF) pathway played a very crucial role in this cascade. We found that Herceptin could reduce tyrosine phosphorylation levels of ErbB2 and beta-catenin. Herceptin treatment induced degradation of beta-catenin protein, resulting in reduced binding affinity of beta-catenin/TCF4 to the promoter region of survivin. When we cross-mutated the TCF4 binding sites in the promoter region of survivin, the reduction of survivin promoter activity almost diminished. Taken together, we showed that Herceptin could inhibit survivin expression through the ErbB2-beta-catenin/TCF4-survivin pathway in ErbB2-overexpressed breast cancer cells. This indicates that there may be a new cascade axis from ErbB2 to survivin.
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Affiliation(s)
- Hongxia Zhu
- Laboratory of Cell and Molecular Biology, State Key Laboratory of Molecular Oncology, Beijing, China
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Hu T, Li C. Convergence between Wnt-β-catenin and EGFR signaling in cancer. Mol Cancer 2010; 9:236. [PMID: 20828404 PMCID: PMC2944186 DOI: 10.1186/1476-4598-9-236] [Citation(s) in RCA: 207] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 09/09/2010] [Indexed: 12/13/2022] Open
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Bitler BG, Menzl I, Huerta CL, Sands B, Knowlton W, Chang A, Schroeder JA. Intracellular MUC1 peptides inhibit cancer progression. Clin Cancer Res 2009; 15:100-9. [PMID: 19118037 DOI: 10.1158/1078-0432.ccr-08-1745] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE During cancer progression, the oncoprotein MUC1 binds beta-catenin while simultaneously inhibiting the degradation of the epidermal growth factor receptor (EGFR), resulting in enhanced transformation and metastasis. The purpose of this study was to design a peptide-based therapy that would block these intracellular protein-protein interactions as a treatment for metastatic breast cancer. EXPERIMENTAL DESIGN The amino acid residues responsible for these interactions lie in tandem in the cytoplasmic domain of MUC1, and we have targeted this sequence to produce a MUC1 peptide that blocks the protumorigenic functions of MUC1. We designed the MUC1 inhibitory peptide (MIP) to block the intracellular interactions between MUC1/beta-catenin and MUC1/EGFR. To allow for cellular uptake we synthesized MIP adjacent to the protein transduction domain, PTD4 (PMIP). RESULTS We have found that PMIP acts in a dominant-negative fashion, blocking both MUC1/beta-catenin and MUC1/EGFR interactions. In addition, PMIP induces ligand-dependent reduction of EGFR levels. These effects correspond to a significant reduction in proliferation, migration, and invasion of metastatic breast cancer cells in vitro, and inhibition of tumor growth and recurrence in an established MDA-MB-231 immunocompromised (SCID) mouse model. Importantly, PMIP also inhibits genetically driven breast cancer progression, as injection of tumor-bearing MMTV-pyV mT transgenic mice with PMIP results in tumor regression and a significant inhibition of tumor growth rate. CONCLUSIONS These data show that intracellular MUC1 peptides possess significant antitumor activity and have important clinical applications in the treatment of cancer.
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Scardigli R, Gargioli C, Tosoni D, Borello U, Sampaolesi M, Sciorati C, Cannata S, Clementi E, Brunelli S, Cossu G. Binding of sFRP-3 to EGF in the extra-cellular space affects proliferation, differentiation and morphogenetic events regulated by the two molecules. PLoS One 2008; 3:e2471. [PMID: 18560570 PMCID: PMC2424011 DOI: 10.1371/journal.pone.0002471] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 05/13/2008] [Indexed: 12/05/2022] Open
Abstract
Background sFRP-3 is a soluble antagonist of Wnts, widely expressed in developing embryos. The Wnt gene family comprises cysteine-rich secreted ligands that regulate cell proliferation, differentiation, organogenesis and oncogenesis of different organisms ranging from worms to mammals. In the canonical signal transduction pathway Wnt proteins bind to the extracellular domain of Frizzled receptors and consequently recruit Dishevelled (Dsh) to the cell membrane. In addition to Wnt membrane receptors belonging to the Frizzled family, several other molecules have been described which share homology in the CRD domain and lack the putative trans-membrane domain, such as sFRP molecules (soluble Frizzled Related Protein). Among them, sFRP-3 was originally isolated from bovine articular cartilage and also as a component of the Spemann organizer. sFRP-3 blocks Wnt-8 induced axis duplication in Xenopus embryos and binds to the surface of cells expressing a membrane-anchored form of Wnt-1. Injection of sFRP-3 mRNA blocks expression of XMyoD mRNA and leads to embryos with enlarged heads and shortened trunks. Methodology/Principal Findings Here we report that sFRP-3 specifically blocks EGF-induced fibroblast proliferation and foci formation. Over-expression of sFRP-3 reverts EGF-mediated inhibition of hair follicle development in the mouse ectoderm while its ablation in Xenopus maintains EGF-mediated inhibition of ectoderm differentiation. Conversely, over-expression of EGF reverts the inhibition of somitic myogenesis and axis truncation in Xenopus and mouse embryos caused by sFRP-3. In vitro experiments demonstrated a direct binding of EGF to sFRP-3 both on heparin and on the surface of CHO cells where the molecule had been membrane anchored. Conclusions/Significance sFRP-3 and EGF reciprocally inhibit their effects on cell proliferation, differentiation and morphogenesis and indeed are expressed in contiguous domains of the embryo, suggesting that in addition to their canonical ligands (Wnt and EGF receptor, respectively) these molecules bind to each other and regulate their activities during embryogenesis.
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Affiliation(s)
- Raffaella Scardigli
- Department of Developmental Biology, Institute of Cell Biology and Tissue Engineering, San Raffaele Biomedical Science Park of Rome, Rome, Italy
- Department of Histology and Medical Embryology, II° Medical School, University of Rome “La Sapienza”, Rome, Italy
| | - Cesare Gargioli
- Department of Developmental Biology, Institute of Cell Biology and Tissue Engineering, San Raffaele Biomedical Science Park of Rome, Rome, Italy
- Department of Histology and Medical Embryology, II° Medical School, University of Rome “La Sapienza”, Rome, Italy
| | - Daniela Tosoni
- Department of Histology and Medical Embryology, II° Medical School, University of Rome “La Sapienza”, Rome, Italy
| | - Ugo Borello
- Department of Histology and Medical Embryology, II° Medical School, University of Rome “La Sapienza”, Rome, Italy
- Stem Cell Research Institute, H. “S. Raffaele”, Milan, Italy
| | - Maurilio Sampaolesi
- Department of Experimental Medicine, University of Pavia, Pavia, Italy
- Interdepartemental Stem Cell Research Institute, University Hospital Gasthuisberg, Leuven, Belgium
| | - Clara Sciorati
- Stem Cell Research Institute, H. “S. Raffaele”, Milan, Italy
| | - Stefano Cannata
- Department of Biology, University of Tor Vergata, Rome, Italy
| | - Emilio Clementi
- Stem Cell Research Institute, H. “S. Raffaele”, Milan, Italy
- Department of Preclinical Sciences, University of Milan, and E. Medea Scientific Institute, Milan, Italy
| | - Silvia Brunelli
- Stem Cell Research Institute, H. “S. Raffaele”, Milan, Italy
- Department of Experimental Medicine, University of Milan-Bicocca, Monza (Milan), Italy
| | - Giulio Cossu
- Department of Developmental Biology, Institute of Cell Biology and Tissue Engineering, San Raffaele Biomedical Science Park of Rome, Rome, Italy
- Stem Cell Research Institute, H. “S. Raffaele”, Milan, Italy
- Department of Biology, University of Milan, Milan, Italy
- * E-mail:
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Pochampalli MR, Bitler BG, Schroeder JA. Transforming growth factor alpha dependent cancer progression is modulated by Muc1. Cancer Res 2007; 67:6591-8. [PMID: 17638868 DOI: 10.1158/0008-5472.can-06-4518] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Transforming growth factor alpha (TGFalpha) is a potent inducer of cellular transformation, through its binding and activation of the epidermal growth factor receptor (EGFR). Previous studies in our laboratory showed that EGFR could also be affected by the glycoprotein MUC1, which inhibits ligand-stimulated degradation of EGFR in breast epithelial cell lines. To determine the effect of Muc1 expression on TGFalpha/EGFR-dependent breast transformation, we crossed the WAP-TGFalpha transgenic mouse model of breast cancer onto a Muc1-null background. We found that the loss of Muc1 expression dramatically affects mammary gland transformation and progression. Although 100% of WAP-TGFalpha/Muc1(+/+) mice form mammary gland tumors by 1 year, only 37% of WAP-TGFalpha/Muc1(-/-) form tumors by this time. This difference is also associated with a delay in onset, with a doubling of onset time observed in the WAP-TGFalpha/Muc1(-/-) compared with the WAP-TGFalpha/Muc1(+/+) mice. Analysis of signal transduction pathways revealed that activation of cyclin D1 expression is significantly suppressed in tumors derived from WAP-TGFalpha/Muc1(-/-) animals compared with those expressing Muc1. The loss of Muc1 expression also results in a significant inhibition in the formation of hyperplastic lesions during tumor progression. On the C57Bl/6 inbred background, pulmonary lesions were observed in 28 of 29 WAP-TGFalpha/Muc1(+/+) animals (including one metastatic pulmonary adenocarcinoma and multiple perivascular lymphomas), although none were detected in the WAP-TGFalpha/Muc1(-/-) animals. Together, these data indicate that Muc1 is an important modulator of TGFalpha-dependent tumor progression.
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Affiliation(s)
- Mamata R Pochampalli
- Department of Molecular and Cellular Biology, Arizona Cancer Center, University of Arizona, 1515 North Campbell Avenue, Tucson, AZ 85724, USA
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Abstract
Transforming growth factor-alpha (TGFalpha) is a member of the epidermal growth factor (EGF) family. Expression of TGFalpha is highly regulated in response to exogenous cellular signals including cytokines and other growth factors. The growth factor has been found to be indispensable for proper development of many tissues and organs. TGFalpha has also been implicated in numerous disease states including forms of breast cancer. This minireview summarizes the basic biology of TGFalpha and its actions during normal and pathogenic development of the mammary epithelium.
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Affiliation(s)
- Brian W Booth
- Mammary Biology and Tumorigenesis Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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11
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Abstract
Ligands of the epidermal growth factor receptor (EGF-R), known to be important for supporting tissue development particularly in the gut and brain, have also been implicated in regulating postnatal somatic growth. Although optimal levels of both milk-borne and endogenous EGF-R ligands are important for supporting postnatal somatic growth through regulating gastrointestinal growth and maturation, supraphysiological levels of EGF-R ligands can cause retarded and disproportionate growth and alter body composition because they can increase growth of epithelial tissues but decrease masses of muscle, fat, and bone. Apart from their indirect roles in influencing growth, possibly via regulating levels of IGF-I and IGF binding proteins, EGF-R ligands can regulate bone growth and modeling directly because they can enhance proliferation but suppress maturation of growth plate chondrocytes (for building a calcified cartilage scaffold for bone deposition), stimulate proliferation but inhibit differentiation of osteoblasts (for depositing bone matrix), and promote formation and function of osteoclasts (for resorption of calcified cartilage or bone). In addition, EGF-like ligands, particularly amphiregulin, can be strongly regulated by PTH, an important regulatory factor in bone modeling and remodeling. Finally, EGF-R ligands can regulate bone homeostasis by regulating a pool of progenitor cells in the bone marrow through promoting proliferation but suppressing differentiation of bone marrow mesenchymal stem cells.
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Affiliation(s)
- Cory J Xian
- Department of Orthopaedic Surgery, Women's and Children's Hospital, 72 King William Road, North Adelaide, South Australia 5006, Australia.
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Turashvili G, Bouchal J, Burkadze G, Kolar Z. Wnt Signaling Pathway in Mammary Gland Development and Carcinogenesis. Pathobiology 2007; 73:213-23. [PMID: 17314492 DOI: 10.1159/000098207] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2006] [Accepted: 10/03/2006] [Indexed: 12/17/2022] Open
Abstract
The signaling pathway mediated by Wingless-type (Wnt) proteins is highly conserved in evolution. This pivotal pathway is known to regulate cell fate decisions, cell proliferation, morphology, migration, apoptosis, differentiation and stem cell self-renewal. It currently includes the canonical or Wnt/beta-catenin pathway in which Wnt proteins bind to 'frizzled' receptors, which leads to downstream activation of gene transcription by beta-catenin. Second, the noncanonical or beta-catenin-independent pathways are now known to be mediated by three possible mechanisms: (1) the Wnt/Ca(2+) pathway, (2) the Wnt/G protein signaling pathway, and (3) the Wnt/PCP or planar cell polarity pathway. Wnt signaling is implicated at several stages of mammary gland growth and differentiation, and possibly in the involution of mammary gland following lactation. Recent evidence suggests the role of Wnt signaling in human breast cancer involves elevated levels of nuclear and/or cytoplasmic beta-catenin using immunohistochemistry, overexpression or downregulation of specific Wnt proteins, overexpression of CKII and sFRP4, downregulation of WIF-1 and sFRP1, as well as amplification of DVL-1. Further research is required to determine how Wnt signaling is involved in the development of different histological types of breast cancer and whether it promotes the viability of cancer stem cells or not.
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Affiliation(s)
- Gulisa Turashvili
- Laboratory of Molecular Pathology, Institute of Pathology, Palacky University, Olomouc, Czech Republic.
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Abstract
BACKGROUND The Ewing sarcoma family of tumors (ESFT) is a set of neuroectodermal malignancies that typically presents in the second decade and has a poor prognosis due to metastatic disease. Wnt signaling has a critical role in the normal development of multiple neuroectodermal tissues and also contributes to the neoplastic properties of tumor cells of neuroectodermal origin. PROCEDURE We surveyed the expression of Wnts and their receptors in nine ESFT cell lines by RT-PCR analysis. We also tested biological response of ESFT cell lines to exogenous Wnts in beta-catenin stabilization, actin stress fiber formation, and chemotaxis assays. RESULTS We detected Wnt-10b in all the lines, and most also expressed Wnt-5a, Wnt-11, and Wnt-13. Several Frizzleds (Fz) and the Wnt co-receptors, low density lipoprotein-receptor-like proteins 5 and 6 were also expressed. We observed a marked stimulation of the beta-catenin/canonical Wnt pathway in ESFT cells treated with Wnt-3a. Wnt-3a induced morphologic changes characterized by the formation of long cytoplasmic extensions in ESFT cells. We also observed chemotaxis of ESFT cells in response to Wnt-3a. CONCLUSIONS These results provide evidence that components of Wnt/Fz pathway are expressed and an intact Wnt/Frizzled signaling pathway exists in ESFT cell lines. Activation of the Wnt pathway in ESFT suggests that Wnt modulates cell motility rather than cell proliferation. Hence, activation of this pathway may influence metastatic potential of ESFT.
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Affiliation(s)
- Aykut Uren
- Georgetown University Medical Center, Lombardi Cancer Center, Research Building, Washington, DC 20057-1469, USA.
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Li C, Franklin JL, Graves-Deal R, Jerome WG, Cao Z, Coffey RJ. Myristoylated Naked2 escorts transforming growth factor alpha to the basolateral plasma membrane of polarized epithelial cells. Proc Natl Acad Sci U S A 2004; 101:5571-6. [PMID: 15064403 PMCID: PMC397424 DOI: 10.1073/pnas.0401294101] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2003] [Indexed: 12/20/2022] Open
Abstract
The epidermal growth factor receptor ligands transforming growth factor alpha (TGF alpha) and amphiregulin are delivered to the basolateral surface of polarized epithelial cells where they are cleaved by TACE/ADAM17. Basolateral sorting information resides in their cytoplasmic tail domains, but tail-interacting proteins required for basolateral trafficking have not been identified. Naked (NKD)1 and NKD2 are mammalian homologs of Drosophila Naked Cuticle, which negatively regulates canonical Wnt signaling by binding Dishevelled. We present evidence that NKD2, but not NKD1, binds to basolateral sorting motifs in the cytoplasmic tail of TGF alpha. Processing and cell-surface delivery of TGF alpha are accelerated in NKD2-overexpressing Madin-Darby canine kidney cells. NKD2 is myristoylated on glycine, the second residue. On expression of myristoylation-defective (G2A) NKD2, neither NKD2 nor TGF alpha appears at the basolateral plasma membrane of polarized Madin-Darby canine kidney cells; however, membrane staining for TGF alpha is restored on silencing expression of this mutant NKD2. Amphiregulin does not interact with NKD2 and retains its basolateral localization in G2A-NKD2-expressing cells, as do Na(+), K(+) ATPase alpha 1 and E-cadherin. These data identify an unexpected function for NKD2, i.e., myristoylation-dependent escort of TGF alpha to the basolateral plasma membrane of polarized epithelial cells.
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Affiliation(s)
- Cunxi Li
- Department of Medicine, Vanderbilt University Medical Center and Department of Veterans Affairs Medical Center, Nashville, TN 37232-2279, USA
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Liu BY, McDermott SP, Khwaja SS, Alexander CM. The transforming activity of Wnt effectors correlates with their ability to induce the accumulation of mammary progenitor cells. Proc Natl Acad Sci U S A 2004; 101:4158-63. [PMID: 15020770 PMCID: PMC384711 DOI: 10.1073/pnas.0400699101] [Citation(s) in RCA: 244] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2003] [Indexed: 12/16/2022] Open
Abstract
Ectopic activation of the Wnt signaling pathway is highly oncogenic for many human tissues. Here, we show that ectopic Wnt signaling increases the effective stem cell activity in mouse mammary glands in vivo. Furthermore, Wnt effectors induce the accumulation of mouse mammary epithelial progenitors (assayed by Hoechst dye exclusion, a surrogate stem cell marker, side population cells) both in vivo and in vitro. The longevity of stem cells makes them good candidate tumor precursors, and we propose that Wnt-induced progenitor amplification is likely to be key to tumor initiation. In support of this notion, mammary glands from a tumor-resistant strain of mice (carrying a null mutation in syndecan-1) contain fewer side population cells. When this strain is crossed to mice that overexpress effectors of the beta-catenin/T cell factor Wnt pathway, the amplification of progenitors is reduced, together with all subsequent events of tumor development. We propose that the growth dynamic of the stem cell fraction is a major determinant of tumor susceptibility.
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Affiliation(s)
- Bob Y Liu
- McArdle Laboratory for Cancer Research, University of Wisconsin Medical School, 1400 University Avenue, Madison, WI 53706-1599, USA
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16
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The transforming activity of Wnt effectors correlates with their ability to induce the accumulation of mammary progenitor cells. Proc Natl Acad Sci U S A 2004. [PMID: 15020770 DOI: 10.1073/pnas.04006991010400699101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ectopic activation of the Wnt signaling pathway is highly oncogenic for many human tissues. Here, we show that ectopic Wnt signaling increases the effective stem cell activity in mouse mammary glands in vivo. Furthermore, Wnt effectors induce the accumulation of mouse mammary epithelial progenitors (assayed by Hoechst dye exclusion, a surrogate stem cell marker, side population cells) both in vivo and in vitro. The longevity of stem cells makes them good candidate tumor precursors, and we propose that Wnt-induced progenitor amplification is likely to be key to tumor initiation. In support of this notion, mammary glands from a tumor-resistant strain of mice (carrying a null mutation in syndecan-1) contain fewer side population cells. When this strain is crossed to mice that overexpress effectors of the beta-catenin/T cell factor Wnt pathway, the amplification of progenitors is reduced, together with all subsequent events of tumor development. We propose that the growth dynamic of the stem cell fraction is a major determinant of tumor susceptibility.
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Musgrove EA. Wnt signalling via the epidermal growth factor receptor: a role in breast cancer? Breast Cancer Res 2003; 6:65-8. [PMID: 14979908 PMCID: PMC400647 DOI: 10.1186/bcr737] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent data have suggested the epidermal-growth-factor receptor (EGFR) as a point of convergence for several different classes of receptor. Civenni and colleagues have now demonstrated crosstalk between Wnt signalling and the EGFR, showing that in breast epithelial cells Wnts activate downstream targets of the EGFR, including cyclin D1. Given the role of members of these pathways in the aetiology of breast cancer and as markers of outcome and potential therapeutic targets in breast cancer, this observation has a number of potential implications important for both the basic biology of breast cancer and the clinical management of the disease.
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Affiliation(s)
- Elizabeth A Musgrove
- Cancer Research Program, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
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Jechlinger M, Grünert S, Beug H. Mechanisms in epithelial plasticity and metastasis: insights from 3D cultures and expression profiling. J Mammary Gland Biol Neoplasia 2002; 7:415-32. [PMID: 12882526 DOI: 10.1023/a:1024090116451] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Most human tumors are of epithelial origin (carcinomas) and metastases from such tumors lead to >80% of all cancer deaths. In contrast to aberrant control of proliferation, cell cycle, apoptosis, angiogenesis, and lifespan, mechanisms involved in local invasion and metastasis are still insufficiently understood. We will review a set of (often conflicting) in vitro/in vivo data that suggest the existence of several types of epithelial cell plasticity changes towards a fibroblastoid, invasive phenotype, which increasingly emerge as crucial events during metastasis. New cellular models were identified, which form organotypic structures under near-physiological 3D-culture conditions in vitro as well as tumors/metastases in vivo. In these models, key proteins and signaling pathways were identified (e.g., TGFbeta, ERK/MAPK, PI3K, and PDGF), which specify distinct types of epithelial plasticity correlated with steps in cancer progression and metastasis. The existence of several distinct epithelial plasticity phenotypes is also strongly suggested by expression profiling of polysome-bound mRNA, yielding a better representation of the proteome than conventional expression profiling.
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Affiliation(s)
- Martin Jechlinger
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
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Schroeder JA, Adriance MC, McConnell EJ, Thompson MC, Pockaj B, Gendler SJ. ErbB-beta-catenin complexes are associated with human infiltrating ductal breast and murine mammary tumor virus (MMTV)-Wnt-1 and MMTV-c-Neu transgenic carcinomas. J Biol Chem 2002; 277:22692-8. [PMID: 11950845 DOI: 10.1074/jbc.m201975200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Simultaneous deregulation of both Wnt and ErbB growth factors has previously been shown to result in the cooperative induction of mammary gland tumors. Using the murine mammary tumor virus (MMTV)-Wnt-1 transgenic model of mammary carcinoma, we have identified an unvarying association between beta-catenin and epidermal growth factor receptor/c-Neu (ErbB1/ErbB2) heterodimers in mammary gland tumors, indicating a requirement for ErbB signaling in Wnt-mediated tumorigenesis. Expansion of these observations to a second transgenic model, MMTV-c-Neu, demonstrated similar tumor-specific interactions, including an ErbB1 ligand-inducible phosphorylation of both beta-catenin and c-Neu. Direct relevance of these findings to human breast cancer was established upon examination of a set of human infiltrating ductal breast adenocarcinoma and lymph node metastasis tissues taken at surgery. These data revealed increased levels of beta-catenin in tumors and metastases versus normal breast as well as an association between beta-catenin and c-Neu that measurably occurs only in neoplasia, most strongly in metastatic lesions. These studies have identified a seemingly indispensable interaction between beta-catenin and epidermal growth factor receptor/c-Neu heterodimers in Wnt-1-mediated breast tumorigenesis that may indicate a fundamental signaling event in human metastatic progression.
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Affiliation(s)
- Joyce A Schroeder
- Tumor Biology Program and Department of Biochemistry and Molecular Biology, Mayo Medical/Graduate School, Mayo Clinic Scottsdale, Scottsdale, Arizona 85259, USA
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Hollmann CA, Kittrell FS, Medina D, Butel JS. Wnt-1 and int-2 mammary oncogene effects on the beta-catenin pathway in immortalized mouse mammary epithelial cells are not sufficient for tumorigenesis. Oncogene 2001; 20:7645-57. [PMID: 11753642 DOI: 10.1038/sj.onc.1204980] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2001] [Revised: 08/22/2001] [Accepted: 09/18/2001] [Indexed: 11/09/2022]
Abstract
Development of strategies for prevention of breast cancer development requires an understanding of the effects of mammary oncogenes on mammary cells at early stages in neoplastic transformation. As mammary oncogenes wnt-1 and int-2 affect different signal transduction pathways, we investigated their effects on established mouse mammary epithelial cell lines (MMECLs) reflecting early stages in tumorigenesis. Normal interactions between beta-catenin and E-cadherin were abrogated in all three immortalized MMECLs and the cells lacked beta-catenin-mediated transactivation activity, detectable using a reporter assay, suggesting that alterations in cell adhesion may be very early events in mammary tumorigenesis. Immortalized FSK4 and EL12 cells and hyperplastic TM3 cells were stably transfected with expression vectors encoding wnt-1 or int-2 or the control vector, and drug-selected pooled cells from each line were confirmed by reverse transcription-polymerase chain reaction to express the transfected oncogene; this expression persisted in the cells analysed in vitro and in vivo. Resultant phenotypic changes depended both on the oncogene and the target mammary cell line. In FSK4 cells, expression of wnt-1 or int-2 resulted in proliferative changes in vitro, including reduced contact inhibition, increased beta-catenin expression, and decreased p53 transcriptional activity, but neither oncogene conferred upon those cells the ability to produce tumors in vivo. EL12 cells were highly refractory to the effects of both oncogenes, with the only measurable changes being increased E-cadherin levels induced by both oncogenes and increased proliferation of the int-2-transfected cells in the absence of serum. Parental TM3 cells were phenotypically similar to wnt-1- or int-2-transfected FSK4 cells and displayed an increased rate of proliferation in vitro and markedly increased tumorigenicity in vivo following transfection with int-2 but not with wnt-1. These results suggest that wnt-1 signaling is redundant in the hyperplastic TM3 cells and indicate that wnt-1-induced effects in the immortalized FSK4 and EL12 cells were not sufficient to mediate a tumorigenic phenotype. This study showed that the wnt-1 and int-2 oncogenes have similar but distinguishable effects on immortalized MMECLs and that the genetic background of the mammary cells greatly influences the consequences of oncogene expression at early stages of cell transformation.
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Affiliation(s)
- C A Hollmann
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA
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Troyer KL, Lee DC. Regulation of mouse mammary gland development and tumorigenesis by the ERBB signaling network. J Mammary Gland Biol Neoplasia 2001; 6:7-21. [PMID: 11467454 DOI: 10.1023/a:1009560330359] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The four ERBB receptors and their multiple polypeptide ligands are differentially expressed during development of the mouse mammary gland. Profiles suggest that ERBB1/EGF receptor (EGFR)4 and ERBB2/Neu are required during ductal morphogenesis, whereas the Neuregulin (NRG) receptors, ERBB3 and ERBB4, are preferentially expressed through alveolar morphogenesis and lactation. Consistent with these profiles, recent gene knockouts established that EGFR and its ligand, Amphiregulin (AR), are essential for ductal morphogenesis in the adolescent mouse and likely provide the required epithelial-stromal signal. In contrast, the phenotypes of transgenic mice expressing dominant negative ERBB2 and ERBB4 proteins suggest that these receptors differentially act to promote or maintain alveolar differentiation. This view of ERBB action provides a conceptual framework for future testing using more sophisticated conditional knockout models. New or existing transgenic mice are also being used to better understand the contributions of ERBB receptors and ligands to mammary tumorigenesis, as well as to more closely mimic the human disease. Recent studies have focused on defining molecular events in neoplastic progression, and in the case of ERBB2/Neu, the requirement for ERBB heterodimerization partners as well as the relative importance of gene amplification versus gene mutation. Collectively, these recent studies establish that normal development and homeostasis of the mammary gland is critically dependent on regulated ERBB signaling. They also illustrate the value of animal models in deciphering roles for the complex ERBB network in this dynamic tissue.
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Affiliation(s)
- K L Troyer
- Department of Microbiology Immunology, University of North Carolina at Chapel Hill, 27599-7260, USA
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