101
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Protein arginine methyltransferase 1 interacts with Gli1 and regulates its transcriptional activity. Tumour Biol 2016; 37:9071-6. [PMID: 26762411 DOI: 10.1007/s13277-015-4754-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Accepted: 12/29/2015] [Indexed: 01/20/2023] Open
Abstract
Protein arginine methylation, which is mediated by the protein arginine methyltransferases (PRMTs), is associated with numerous fundamental cellular processes. Our previous studies have shown that PRMT1 activated Hedgehog signaling in the esophageal squamous cell carcinoma (ESCC) cells and promoted the growth and migration of cancer cells. However, the detailed mechanisms are unknown. In this study, it was found that PRMT1 interacted with the transcriptional factor Gli1 (glioma-associated oncogene homolog 1) in ESCC cells. The DNA-binding domain (DBD) of Gli1 is responsible for its interaction with PRMT1. Moreover, PRMT1 promoted the methylation of Gli1, and knocking down the expression of PRMT1 impaired the transcriptional activity as well as the biological functions of Gli1. Taken together, our study demonstrated that PRMT1 is a positive regulator of Hedgehog signaling, and PRMT1 might be a therapeutic target for ESCC.
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102
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YB-1 is elevated in medulloblastoma and drives proliferation in Sonic hedgehog-dependent cerebellar granule neuron progenitor cells and medulloblastoma cells. Oncogene 2016; 35:4256-68. [PMID: 26725322 PMCID: PMC4931992 DOI: 10.1038/onc.2015.491] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 10/26/2015] [Accepted: 11/27/2015] [Indexed: 12/29/2022]
Abstract
Postnatal proliferation of cerebellar granule neuron precursors (CGNPs), proposed cells of origin for the SHH-associated subgroup of medulloblastoma, is driven by Sonic hedgehog (Shh) and insulin-like growth factor (IGF) in the developing cerebellum. Shh induces the oncogene Yes-associated protein (YAP), which drives IGF2 expression in CGNPs and mouse Shh-associated medulloblastomas. To determine how IGF2 expression is regulated downstream of YAP, we carried out an unbiased screen for transcriptional regulators bound to IGF2 promoters. We report that Y-box binding protein-1 (YB-1), an onco-protein regulating transcription and translation, binds to IGF2 promoter P3. We observed that YB-1 is upregulated across human medulloblastoma subclasses as well as in other varieties of pediatric brain tumors. Utilizing the cerebellar progenitor model for the Shh subgroup of medulloblastoma in mice, we show for the first time that YB-1 is induced by Shh in CGNPs. Its expression is YAP-dependent and it is required for IGF2 expression in CGNPs. Finally, both gain-of function and loss-of-function experiments reveal that YB-1 activity is required for sustaining CGNP and medulloblastoma cell (MBC) proliferation. Collectively, our findings describe a novel role for YB-1 in driving proliferation in the developing cerebellum and MBCs and they identify the SHH:YAP:YB1:IGF2 axis as a powerful target for therapeutic intervention in medulloblastomas.
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103
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Morales AV, Espeso-Gil S, Ocaña I, Nieto-Lopez F, Calleja E, Bovolenta P, Lewandoski M, Diez Del Corral R. FGF signaling enhances a sonic hedgehog negative feedback loop at the initiation of spinal cord ventral patterning. Dev Neurobiol 2015; 76:956-71. [PMID: 26600420 DOI: 10.1002/dneu.22368] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 11/18/2015] [Indexed: 12/23/2022]
Abstract
A prevalent developmental mechanism for the assignment of cell identities is the production of spatiotemporal concentration gradients of extracellular signaling molecules that are interpreted by the responding cells. One of such signaling systems is the Shh gradient that controls neuronal subtype identity in the ventral spinal cord. Using loss and gain of function approaches in chick and mouse embryos, we show here that the fibroblast growth factor (FGF) signaling pathway is required to restrict the domains of ventral gene expression as neuroepithelial cells become exposed to Shh during caudal extension of the embryo. FGF signaling activates the expression of the Shh receptor and negative pathway regulator Patched 2 (Ptch2) and therefore can enhance a negative feedback loop that restrains the activity of the pathway. Thus, we identify one of the mechanisms by which FGF signaling acts as a modulator of the onset of Shh signaling activity in the context of coordination of ventral patterning and caudal axis extension. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 956-971, 2016.
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Affiliation(s)
- Aixa V Morales
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, 28002, Spain
| | - Sergio Espeso-Gil
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, 28002, Spain
| | - Inmaculada Ocaña
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, 28002, Spain.,CIBER de Enfermedades Raras, Spain
| | - Francisco Nieto-Lopez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, 28002, Spain.,CIBER de Enfermedades Raras, Spain.,Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas-UAM, Cantoblanco, 28049, Spain
| | - Elena Calleja
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, 28002, Spain
| | - Paola Bovolenta
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, 28002, Spain.,CIBER de Enfermedades Raras, Spain.,Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas-UAM, Cantoblanco, 28049, Spain
| | - Mark Lewandoski
- Cancer and Developmental Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702, USA
| | - Ruth Diez Del Corral
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, 28002, Spain
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104
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Li C, Li M, Li S, Xing Y, Yang CY, Li A, Borok Z, De Langhe S, Minoo P. Progenitors of secondary crest myofibroblasts are developmentally committed in early lung mesoderm. Stem Cells 2015; 33:999-1012. [PMID: 25448080 DOI: 10.1002/stem.1911] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 10/20/2014] [Accepted: 11/10/2014] [Indexed: 11/09/2022]
Abstract
Development of the mammalian lung is predicated on cross-communications between two highly interactive tissues, the endodermally derived epithelium and the mesodermally derived pulmonary mesenchyme. While much attention has been paid for the lung epithelium, the pulmonary mesenchyme, partly due to lack of specific tractable markers remains under-investigated. The lung mesenchyme is derived from the lateral plate mesoderm and is the principal recipient of Hedgehog (Hh) signaling, a morphogenetic network that regulates multiple aspects of embryonic development. Using the Hh-responsive Gli1-cre(ERT2) mouse line, we identified the mesodermal targets of Hh signaling at various time points during embryonic and postnatal lung development. Cell lineage analysis showed these cells serve as progenitors to contribute to multiple lineages of mesodermally derived differentiated cell types that include parenchymal or interstitial myofibroblasts, peribronchial and perivascular smooth muscle as well as rare populations of cells within the mesothelium. Most importantly, Gli1-cre(ERT2) identified the progenitors of secondary crest myofibroblasts, a hitherto intractable cell type that plays a key role in alveolar formation, a vital process about which little is currently known. Transcriptome analysis of Hh-targeted progenitor cells transitioning from the pseudoglandular to the saccular phase of lung development revealed important modulations of key signaling pathways. Among these, there was significant downregulation of canonical WNT signaling. Ectopic stabilization of β-catenin via inactivation of Apc by Gli1-cre(ERT2) expanded the Hh-targeted progenitor pools, which caused the formation of fibroblastic masses within the lung parenchyma. The Gli1-cre(ERT2) mouse line represents a novel tool in the analysis of mesenchymal cell biology and alveolar formation during lung development.
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Affiliation(s)
- Changgong Li
- Division of Newborn Medicine, Department of Pediatrics, Los Angeles County+University of Southern California Medical Center and Childrens Hospital Los Angeles
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105
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Li ASW, Marikawa Y. An in vitro gastrulation model recapitulates the morphogenetic impact of pharmacological inhibitors of developmental signaling pathways. Mol Reprod Dev 2015; 82:1015-36. [PMID: 26387793 DOI: 10.1002/mrd.22585] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/17/2015] [Indexed: 12/21/2022]
Abstract
Certain chemical agents act as teratogens, causing birth defects and fetal deaths when pregnant women are exposed to them. The establishment of in vitro models that recapitulate crucial embryonic events is therefore vital to facilitate screening of potential teratogens. Previously, we created a three-dimensional culture method for mouse P19C5 embryonal carcinoma stem cells that, when cultured as embryoid bodies, display elongation morphogenesis resembling gastrulation, which is the critical event resulting in the germ layers and major body axes. Determination of how well this in vitro morphogenesis represents in vivo gastrulation is essential to assess its applicability as well as to identify limitations of the model for detecting teratogenic agents. Here, we investigated the morphological and molecular characteristics of P19C5 morphogenesis using pharmacological agents that are known to cause abnormal patterning in the embryo in vivo by inhibiting major developmental signaling--e.g., involving Wnt, Nodal, Bone morphogenic protein (Bmp), Fibroblast growth factor (Fgf), Retinoic acid, Notch, and Hedgehog pathways. Inhibitors of Wnt, Nodal, Bmp, Fgf, and Retinoic acid signaling caused distinct changes in P19C5 morphogenesis that were quantifiable using morphometric parameters. These five inhibitors, plus the Notch inhibitor, also altered temporal expression profiles of developmental regulator genes in a manner consistent with the in vivo roles of the corresponding signaling pathways. In contrast, the Hedgehog inhibitor did not have any impact on the process, suggesting an absence of active Hedgehog signaling in these embryoid bodies. These results indicate that the P19C5 in vitro gastrulation model is a promising tool to screen for teratogenic agents that interfere with many of the key developmental signals.
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Affiliation(s)
- Aileen S W Li
- Developmental and Reproductive Biology Graduate Program, Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Hawaii
| | - Yusuke Marikawa
- Developmental and Reproductive Biology Graduate Program, Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Hawaii
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106
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The Role of Hedgehog Signaling in Tumor Induced Bone Disease. Cancers (Basel) 2015; 7:1658-83. [PMID: 26343726 PMCID: PMC4586789 DOI: 10.3390/cancers7030856] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/13/2015] [Accepted: 08/18/2015] [Indexed: 12/21/2022] Open
Abstract
Despite significant progress in cancer treatments, tumor induced bone disease continues to cause significant morbidities. While tumors show distinct mutations and clinical characteristics, they behave similarly once they establish in bone. Tumors can metastasize to bone from distant sites (breast, prostate, lung), directly invade into bone (head and neck) or originate from the bone (melanoma, chondrosarcoma) where they cause pain, fractures, hypercalcemia, and ultimately, poor prognoses and outcomes. Tumors in bone secrete factors (interleukins and parathyroid hormone-related protein) that induce RANKL expression from osteoblasts, causing an increase in osteoclast mediated bone resorption. While the mechanisms involved varies slightly between tumor types, many tumors display an increase in Hedgehog signaling components that lead to increased tumor growth, therapy failure, and metastasis. The work of multiple laboratories has detailed Hh signaling in several tumor types and revealed that tumor establishment in bone can be controlled by both canonical and non-canonical Hh signaling in a cell type specific manner. This review will explore the role of Hh signaling in the modulation of tumor induced bone disease, and will shed insight into possible therapeutic interventions for blocking Hh signaling in these tumors.
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107
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Bandín S, Morona R, González A. Prepatterning and patterning of the thalamus along embryonic development of Xenopus laevis. Front Neuroanat 2015; 9:107. [PMID: 26321920 PMCID: PMC4530589 DOI: 10.3389/fnana.2015.00107] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 07/24/2015] [Indexed: 01/18/2023] Open
Abstract
Previous developmental studies of the thalamus (alar part of the diencephalic prosomere p2) have defined the molecular basis for the acquisition of the thalamic competence (preparttening), the subsequent formation of the secondary organizer in the zona limitans intrathalamica, and the early specification of two anteroposterior domains (rostral and caudal progenitor domains) in response to inducing activities and that are shared in birds and mammals. In the present study we have analyzed the embryonic development of the thalamus in the anuran Xenopus laevis to determine conserved or specific features in the amphibian diencephalon. From early embryonic stages to the beginning of the larval period, the expression patterns of 22 markers were analyzed by means of combined In situ hybridization (ISH) and immunohistochemical techniques. The early genoarchitecture observed in the diencephalon allowed us to discern the boundaries of the thalamus with the prethalamus, pretectum, and epithalamus. Common molecular features were observed in the thalamic prepatterning among vertebrates in which Wnt3a, Fez, Pax6 and Xiro1 expression were of particular importance in Xenopus. The formation of the zona limitans intrathalamica was observed, as in other vertebrates, by the progressive expression of Shh. The largely conserved expressions of Nkx2.2 in the rostral thalamic domain vs. Gbx2 and Ngn2 (among others) in the caudal domain strongly suggest the role of Shh as morphogen in the amphibian thalamus. All these data showed that the molecular characteristics observed during preparttening and patterning in the thalamus of the anuran Xenopus (anamniote) share many features with those described during thalamic development in amniotes (common patterns in tetrapods) but also with zebrafish, strengthening the idea of a basic organization of this diencephalic region across vertebrates.
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Affiliation(s)
- Sandra Bandín
- Faculty of Biology, Department of Cell Biology, University Complutense Madrid, Spain
| | - Ruth Morona
- Faculty of Biology, Department of Cell Biology, University Complutense Madrid, Spain
| | - Agustín González
- Faculty of Biology, Department of Cell Biology, University Complutense Madrid, Spain
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108
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Jackson DA, Smith TD, Amarsaikhan N, Han W, Neil MS, Boi SK, Vrabel AM, Tolosa EJ, Almada LL, Fernandez-Zapico ME, Elsawa SF. Modulation of the IL-6 Receptor α Underlies GLI2-Mediated Regulation of Ig Secretion in Waldenström Macroglobulinemia Cells. THE JOURNAL OF IMMUNOLOGY 2015; 195:2908-16. [PMID: 26238488 DOI: 10.4049/jimmunol.1402974] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 07/14/2015] [Indexed: 12/15/2022]
Abstract
Ig secretion by terminally differentiated B cells is an important component of the immune response to foreign pathogens. Its overproduction is a defining characteristic of several B cell malignancies, including Waldenström macroglobulinemia (WM), where elevated IgM is associated with significant morbidity and poor prognosis. Therefore, the identification and characterization of the mechanisms controlling Ig secretion are of great importance for the development of future therapeutic approaches for this disease. In this study, we define a novel pathway involving the oncogenic transcription factor GLI2 modulating IgM secretion by WM malignant cells. Pharmacological and genetic inhibition of GLI2 in WM malignant cells resulted in a reduction in IgM secretion. Screening for a mechanism identified the IL-6Rα (gp80) subunit as a downstream target of GLI2 mediating the regulation of IgM secretion. Using a combination of expression, luciferase, and chromatin immunoprecipitation assays we demonstrate that GLI2 binds to the IL-6Rα promoter and regulates its activity as well as the expression of this receptor. Additionally, we were able to rescue the reduction in IgM secretion in the GLI2 knockdown group by overexpressing IL-6Rα, thus defining the functional significance of this receptor in GLI2-mediated regulation of IgM secretion. Interestingly, this occurred independent of Hedgehog signaling, a known regulator of GLI2, as manipulation of Hedgehog had no effect on IgM secretion. Given the poor prognosis associated with elevated IgM in WM patients, components of this new signaling axis could be important therapeutic targets.
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Affiliation(s)
- David A Jackson
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115; and
| | - Timothy D Smith
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115; and
| | - Nansalmaa Amarsaikhan
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115; and
| | - Weiguo Han
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115; and
| | - Matthew S Neil
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115; and
| | - Shannon K Boi
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115; and
| | - Anne M Vrabel
- Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, MN 55905
| | - Ezequiel J Tolosa
- Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, MN 55905
| | - Luciana L Almada
- Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, MN 55905
| | | | - Sherine F Elsawa
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115; and
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109
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Expression Profile of Sonic Hedgehog Pathway Members in the Developing Human Fetal Brain. BIOMED RESEARCH INTERNATIONAL 2015; 2015:494269. [PMID: 26266257 PMCID: PMC4523658 DOI: 10.1155/2015/494269] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 03/29/2015] [Accepted: 03/30/2015] [Indexed: 11/17/2022]
Abstract
The Sonic Hedgehog (SHH) pathway plays a central role in the developing mammalian CNS. In our study, we aimed to investigate the spatiotemporal SHH pathway expression pattern in human fetal brains. We analyzed 22 normal fetal brains for Shh, Patched, Smoothened, and Gli1-3 expression by immunohistochemistry. In the telencephalon, strongest expression of Shh, Smoothened, and Gli2 was found in the cortical plate (CP) and ventricular zone. Patched was strongly upregulated in the ventricular zone and Gli1 in the CP. In the cerebellum, SHH pathway members were strongly expressed in the external granular layer (EGL). SHH pathway members significantly decreased over time in the ventricular and subventricular zone and in the cerebellar EGL, while increasing levels were found in more superficial telencephalic layers. Our findings show that SHH pathway members are strongly expressed in areas important for proliferation and differentiation and indicate a temporal expression gradient in telencephalic and cerebellar layers probably due to decreased proliferation of progenitor cells and increased differentiation. Our data about the spatiotemporal expression of SHH pathway members in the developing human brain serves as a base for the understanding of both normal and pathological CNS development.
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110
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Serpine2/PN-1 Is Required for Proliferative Expansion of Pre-Neoplastic Lesions and Malignant Progression to Medulloblastoma. PLoS One 2015; 10:e0124870. [PMID: 25901736 PMCID: PMC4406471 DOI: 10.1371/journal.pone.0124870] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/18/2015] [Indexed: 12/13/2022] Open
Abstract
Background Medulloblastomas are malignant childhood brain tumors that arise due to the aberrant activity of developmental pathways during postnatal cerebellar development and in adult humans. Transcriptome analysis has identified four major medulloblastoma subgroups. One of them, the Sonic hedgehog (SHH) subgroup, is caused by aberrant Hedgehog signal transduction due to mutations in the Patched1 (PTCH1) receptor or downstream effectors. Mice carrying a Patched-1 null allele (Ptch1∆/+) are a good model to study the alterations underlying medulloblastoma development as a consequence of aberrant Hedgehog pathway activity. Results Transcriptome analysis of human medulloblastomas shows that SERPINE2, also called Protease Nexin-1 (PN-1) is overexpressed in most medulloblastomas, in particular in the SHH and WNT subgroups. As siRNA-mediated lowering of SERPINE2/PN-1 in human medulloblastoma DAOY cells reduces cell proliferation, we analyzed its potential involvement in medulloblastoma development using the Ptch1∆/+ mouse model. In Ptch1∆/+ mice, medulloblastomas arise as a consequence of aberrant Hedgehog pathway activity. Genetic reduction of Serpine2/Pn-1 interferes with medulloblastoma development in Ptch1∆/+ mice, as ~60% of the pre-neoplastic lesions (PNLs) fail to develop into medulloblastomas and remain as small cerebellar nodules. In particular the transcription factor Atoh1, whose expression is essential for development of SHH subgroup medulloblastomas is lost. Comparative molecular analysis reveals the distinct nature of the PNLs in young Ptch1∆/+Pn-1Δ/+ mice. The remaining wild-type Ptch1 allele escapes transcriptional silencing in most cases and the aberrant Hedgehog pathway activity is normalized. Furthermore, cell proliferation and the expression of the cell-cycle regulators Mycn and Cdk6 are significantly reduced in PNLs of Ptch1∆/+Pn-1Δ/+ mice. Conclusions Our analysis provides genetic evidence that aberrant Serpine2/Pn-1 is required for proliferation of human and mouse medulloblastoma cells. In summary, our analysis shows that Serpine2/PN-1 boosts malignant progression of PNLs to medulloblastomas, in which the Hedgehog pathway is activated in a SHH ligand-independent manner.
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111
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Activation of Sonic Hedgehog Leads to Survival Enhancement of Astrocytes via the GRP78-Dependent Pathway in Mice Infected with Angiostrongylus cantonensis. BIOMED RESEARCH INTERNATIONAL 2015; 2015:674371. [PMID: 25961032 PMCID: PMC4415671 DOI: 10.1155/2015/674371] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 03/16/2015] [Indexed: 01/28/2023]
Abstract
Angiostrongylus cantonensis infection may cause elevation of ROS and antioxidants in the CSF of infected mice. Astrocytes may protect the surrounding neurons from oxidative stress-induced cell death by secreting Sonic hedgehog (Shh) via the PI3-K/AKT/Bcl-2 pathway. This study was conducted to determine the role of the Shh signaling pathway in A. cantonensis-infected BABL/c mice by coculturing astrocytes with living fifth-stage larvae or soluble antigens. The Shh pathway was activated with corresponding increases in the level of the Shh. Glial fibrillary acidic protein (GFAP) and Shh were increased in astrocyte cocultured with living fifth-stage larvae or soluble antigens. The survival of astrocytes pretreated with Shh was significantly elevated in cocultures with the antigens but reduced by its inhibitor cyclopamine. The expression of GRP78 and Bcl-2 was significantly higher in astrocytes pretreated with recombinant Shh. These findings suggest that the expression of Shh may inhibit cell death by activating Bcl-2 through a GRP78-dependent pathway.
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112
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Minhas R, Pauls S, Ali S, Doglio L, Khan MR, Elgar G, Abbasi AA. Cis-regulatory control of human GLI2 expression in the developing neural tube and limb bud. Dev Dyn 2015; 244:681-92. [DOI: 10.1002/dvdy.24266] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/29/2015] [Accepted: 02/16/2015] [Indexed: 11/08/2022] Open
Affiliation(s)
- Rashid Minhas
- National Center for Bioinformatics; Program of Comparative and Evolutionary Genomics; Faculty of Biological Sciences; Quaid-i-Azam University; Islamabad 45320 Pakistan
| | - Stefan Pauls
- Division of Systems Biology; MRC National Institute for Medical Research; The Ridgeway, Mill Hill London NW7 1AA United Kingdom
| | - Shahid Ali
- National Center for Bioinformatics; Program of Comparative and Evolutionary Genomics; Faculty of Biological Sciences; Quaid-i-Azam University; Islamabad 45320 Pakistan
| | - Laura Doglio
- Division of Systems Biology; MRC National Institute for Medical Research; The Ridgeway, Mill Hill London NW7 1AA United Kingdom
| | - Muhammad Ramzan Khan
- National Institute for Genomics and Advanced Biotechnology; National Agricultural Research Center; Park Road Islamabad Pakistan
| | - Greg Elgar
- Division of Systems Biology; MRC National Institute for Medical Research; The Ridgeway, Mill Hill London NW7 1AA United Kingdom
| | - Amir Ali Abbasi
- National Center for Bioinformatics; Program of Comparative and Evolutionary Genomics; Faculty of Biological Sciences; Quaid-i-Azam University; Islamabad 45320 Pakistan
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113
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Cohen M, Kicheva A, Ribeiro A, Blassberg R, Page KM, Barnes CP, Briscoe J. Ptch1 and Gli regulate Shh signalling dynamics via multiple mechanisms. Nat Commun 2015; 6:6709. [PMID: 25833741 PMCID: PMC4396374 DOI: 10.1038/ncomms7709] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 02/20/2015] [Indexed: 12/20/2022] Open
Abstract
In the vertebrate neural tube, the morphogen Sonic Hedgehog (Shh) establishes a characteristic pattern of gene expression. Here we quantify the Shh gradient in the developing mouse neural tube and show that while the amplitude of the gradient increases over time, the activity of the pathway transcriptional effectors, Gli proteins, initially increases but later decreases. Computational analysis of the pathway suggests three mechanisms that could contribute to this adaptation: transcriptional upregulation of the inhibitory receptor Ptch1, transcriptional downregulation of Gli and the differential stability of active and inactive Gli isoforms. Consistent with this, Gli2 protein expression is downregulated during neural tube patterning and adaptation continues when the pathway is stimulated downstream of Ptch1. Moreover, the Shh-induced upregulation of Gli2 transcription prevents Gli activity levels from adapting in a different cell type, NIH3T3 fibroblasts, despite the upregulation of Ptch1. Multiple mechanisms therefore contribute to the intracellular dynamics of Shh signalling, resulting in different signalling dynamics in different cell types.
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Affiliation(s)
- Michael Cohen
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Anna Kicheva
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Ana Ribeiro
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Robert Blassberg
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Karen M Page
- Department of Mathematics and CoMPLEX, University College London, Gower Street, London WC1E 6BT, UK
| | - Chris P Barnes
- 1] Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK [2] Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - James Briscoe
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
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114
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Haddad-Tóvolli R, Paul FA, Zhang Y, Zhou X, Theil T, Puelles L, Blaess S, Alvarez-Bolado G. Differential requirements for Gli2 and Gli3 in the regional specification of the mouse hypothalamus. Front Neuroanat 2015; 9:34. [PMID: 25859185 PMCID: PMC4373379 DOI: 10.3389/fnana.2015.00034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/09/2015] [Indexed: 11/13/2022] Open
Abstract
Secreted protein Sonic hedgehog (Shh) ventralizes the neural tube by modulating the crucial balance between activating and repressing functions (GliA, GliR) of transcription factors Gli2 and Gli3. This balance—the Shh-Gli code—is species- and context-dependent and has been elucidated for the mouse spinal cord. The hypothalamus, a forebrain region regulating vital functions like homeostasis and hormone secretion, shows dynamic and intricate Shh expression as well as complex regional differentiation. Here we asked if particular combinations of Gli2 and Gli3 and of GliA and GliR functions contribute to the variety of hypothalamic regions, i.e., we wanted to approach the question of a possible hypothalamic version of the Shh-Gli code. Based on mouse mutant analysis, we show that: (1) hypothalamic regional heterogeneity is based in part on differentially stringent requirements for Gli2 or Gli3; (2) another source of diversity are differential requirements for Shh of neural vs. non-neural origin; (3) the medial progenitor domain known to depend on Gli2 for its development generates several essential hypothalamic nuclei plus the pituitary and median eminence; (4) the suppression of Gli3R by neural and non-neural Shh is essential for hypothalamic specification. Finally, we have mapped our results on a recent model which considers the hypothalamus as a transverse region with alar and basal portions. Our data confirm the model and are explained by it.
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Affiliation(s)
- Roberta Haddad-Tóvolli
- Department of Medical Cell Biology and Neuroanatomy, University of Heidelberg Heidelberg, Germany
| | - Fabian A Paul
- Laboratory of Neurodevelopmental Genetics, Institute of Reconstructive Neurobiology, Life and Brain Center, University of Bonn Bonn, Germany
| | - Yuanfeng Zhang
- Department of Medical Cell Biology and Neuroanatomy, University of Heidelberg Heidelberg, Germany
| | - Xunlei Zhou
- Department of Medical Cell Biology and Neuroanatomy, University of Heidelberg Heidelberg, Germany
| | - Thomas Theil
- Centre for Integrative Physiology, University of Edinburgh Edinburgh, UK
| | - Luis Puelles
- Department of Morphology, Instituto Murciano de Investigación Biosanitaria, School of Medicine, University of Murcia Murcia, Spain ; Facultad de Medicina, University of Murcia Murcia, Spain
| | - Sandra Blaess
- Laboratory of Neurodevelopmental Genetics, Institute of Reconstructive Neurobiology, Life and Brain Center, University of Bonn Bonn, Germany
| | - Gonzalo Alvarez-Bolado
- Department of Medical Cell Biology and Neuroanatomy, University of Heidelberg Heidelberg, Germany
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Inversion of Sonic hedgehog action on its canonical pathway by electrical activity. Proc Natl Acad Sci U S A 2015; 112:4140-5. [PMID: 25829542 DOI: 10.1073/pnas.1419690112] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Sonic hedgehog (Shh) is a morphogenic protein that operates through the Gli transcription factor-dependent canonical pathway to orchestrate normal development of many tissues. Because aberrant levels of Gli activity lead to a wide spectrum of diseases ranging from neurodevelopmental defects to cancer, understanding the regulatory mechanisms of Shh canonical pathway is paramount. During early stages of spinal cord development, Shh specifies neural progenitors through the canonical signaling. Despite persistence of Shh as spinal cord development progresses, Gli activity is switched off by unknown mechanisms. In this study we find that Shh inverts its action on Gli during development. Strikingly, Shh decreases Gli signaling in the embryonic spinal cord by an electrical activity- and cAMP-dependent protein kinase-mediated pathway. The inhibition of Gli activity by Shh operates at multiple levels. Shh promotes cytosolic over nuclear localization of Gli2, induces Gli2 and Gli3 processing into repressor forms, and activates cAMP-responsive element binding protein that in turn represses gli1 transcription. The regulatory mechanisms identified in this study likely operate with different spatiotemporal resolution and ensure effective down-regulation of the canonical Shh signaling as spinal cord development progresses. The developmentally regulated intercalation of electrical activity in the Shh pathway may represent a paradigm for switching from canonical to noncanonical roles of developmental cues during neuronal differentiation and maturation.
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Conserved role of Sonic Hedgehog in tonotopic organization of the avian basilar papilla and mammalian cochlea. Proc Natl Acad Sci U S A 2015; 112:3746-51. [PMID: 25775517 DOI: 10.1073/pnas.1417856112] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Sound frequency discrimination begins at the organ of Corti in mammals and the basilar papilla in birds. Both of these hearing organs are tonotopically organized such that sensory hair cells at the basal (proximal) end respond to high frequency sound, whereas their counterparts at the apex (distal) respond to low frequencies. Sonic hedgehog (Shh) secreted by the developing notochord and floor plate is required for cochlear formation in both species. In mice, the apical region of the developing cochlea, closer to the ventral midline source of Shh, requires higher levels of Shh signaling than the basal cochlea farther away from the midline. Here, gain-of-function experiments using Shh-soaked beads in ovo or a mouse model expressing constitutively activated Smoothened (transducer of Shh signaling) show up-regulation of apical genes in the basal cochlea, even though these regionally expressed genes are not necessarily conserved between the two species. In chicken, these altered gene expression patterns precede morphological and physiological changes in sensory hair cells that are typically associated with tonotopy such as the total number of stereocilia per hair cell and gene expression of an inward rectifier potassium channel, IRK1, which is a bona fide feature of apical hair cells in the basilar papilla. Furthermore, our results suggest that this conserved role of Shh in establishing cochlear tonotopy is initiated early in development by Shh emanating from the notochord and floor plate.
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Gao Q, Yuan Y, Gan HZ, Peng Q. Resveratrol inhibits the hedgehog signaling pathway and epithelial-mesenchymal transition and suppresses gastric cancer invasion and metastasis. Oncol Lett 2015; 9:2381-2387. [PMID: 26137075 DOI: 10.3892/ol.2015.2988] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Accepted: 01/22/2015] [Indexed: 12/22/2022] Open
Abstract
The hedgehog (Hh) signaling pathway is vital to vertebrate development, the homeostatic process and tumorigenesis. Epithelial-mesenchymal transition (EMT) is a cellular process during which epithelial cells become mesenchymal-appearing cells, which in turn promotes cancer metastasis and invasion. Resveratrol is a natural polyphenolic compound found in grapes, a variety of berries, peanuts and other plants. Numerous studies have demonstrated that the Hh signaling pathway is able to regulate the EMT, and that resveratrol can suppress carcinoma invasion and metastasis. In addition, certain studies have indicated that resveratrol can inhibit the Hh signaling pathway and EMT in cancers other than gastric cancer. The purpose of the present study was to investigate the inhibitory effect of resveratrol on the Hh signaling pathway and EMT in gastric cancer in vitro. Gastric cancer SGC-7901 cells were treated with resveratrol or cyclopamine at different concentrations. The viability of the cells was assessed using an MTT assay. The expression of Gli-1, a key component of the Hh signaling pathway, and Snail, E-cadherin and N-cadherin, key components of EMT, was detected by reverse transcription polymerase chain reaction (RT-PCR) and western blotting. The invasion and metastasis of the cells were observed by performing a cell scratch test. The RT-PCR and western blotting showed a decrease in Gli-1, Snail and N-cadherin expression, and an increase in E-cadherin expression in the resveratrol and cyclopamine group compared with the control group, suggesting that resveratrol inhibited the Hh pathway and EMT, as did cyclopamine. The MTT assay indicated that the viability of the SGC-7901 cells was significantly decreased in a concentration-dependent manner following resveratrol and cyclopamine treatment. The cell scratch test showed slower cell invasion and metastasis in the resveratrol and cyclopamine groups. These findings indicated that resveratrol was able to inhibit the Hh signaling pathway and EMT, and suppress invasion and metastasis in gastric cancer in vitro.
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Affiliation(s)
- Qian Gao
- Department of Gastroenterology, The Third Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230061, P.R. China
| | - Yuan Yuan
- Central Laboratory of Binhu Hospital, The Third Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230601, P.R. China
| | - Hui-Zhong Gan
- Department of Gastroenterology, The Third Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230061, P.R. China
| | - Qiong Peng
- Department of Gastroenterology, The Third Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230061, P.R. China
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118
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Cooperative integration between HEDGEHOG-GLI signalling and other oncogenic pathways: implications for cancer therapy. Expert Rev Mol Med 2015; 17:e5. [PMID: 25660620 PMCID: PMC4836208 DOI: 10.1017/erm.2015.3] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The HEDGEHOG-GLI (HH-GLI) signalling is a key pathway critical in embryonic development, stem cell biology and tissue homeostasis. In recent years, aberrant activation of HH-GLI signalling has been linked to several types of cancer, including those of the skin, brain, lungs, prostate, gastrointestinal tract and blood. HH-GLI signalling is initiated by binding of HH ligands to the transmembrane receptor PATCHED and is mediated by transcriptional effectors that belong to the GLI family, whose activity is finely tuned by a number of molecular interactions and post-translation modifications. Several reports suggest that the activity of the GLI proteins is regulated by several proliferative and oncogenic inputs, in addition or independent of upstream HH signalling. The identification of this complex crosstalk and the understanding of how the major oncogenic signalling pathways interact in cancer is a crucial step towards the establishment of efficient targeted combinatorial treatments. Here we review recent findings on the cooperative integration of HH-GLI signalling with the major oncogenic inputs and we discuss how these cues modulate the activity of the GLI proteins in cancer. We then summarise the latest advances on SMO and GLI inhibitors and alternative approaches to attenuate HH signalling through rational combinatorial therapies.
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119
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Lin C, Yao E, Wang K, Nozawa Y, Shimizu H, Johnson JR, Chen JN, Krogan NJ, Chuang PT. Regulation of Sufu activity by p66β and Mycbp provides new insight into vertebrate Hedgehog signaling. Genes Dev 2015; 28:2547-63. [PMID: 25403183 PMCID: PMC4233246 DOI: 10.1101/gad.249425.114] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Control of Gli function by Sufu, a major negative regulator, is a key step in mammalian Hedgehog (Hh) signaling. Lin et al. identified several Sufu-interacting proteins, including p66β and Mycbp. Sufu recruits p66β to block Gli-mediated Hh target gene expression. Meanwhile, Mycbp forms a complex with Gli and Sufu without Hh stimulation but remains inactive. Hh pathway activation leads to dissociation of Sufu/p66β from Gli, enabling Mycbp to promote Gli protein activity and Hh target gene expression. Control of Gli function by Suppressor of Fused (Sufu), a major negative regulator, is a key step in mammalian Hedgehog (Hh) signaling, but how this is achieved in the nucleus is unknown. We found that Hh signaling results in reduced Sufu protein levels and Sufu dissociation from Gli proteins in the nucleus, highlighting critical functions of Sufu in the nucleus. Through a proteomic approach, we identified several Sufu-interacting proteins, including p66β (a member of the NuRD [nucleosome remodeling and histone deacetylase] repressor complex) and Mycbp (a Myc-binding protein). p66β negatively and Mycbp positively regulate Hh signaling in cell-based assays and zebrafish. They function downstream from the membrane receptors, Patched and Smoothened, and the primary cilium. Sufu, p66β, Mycbp, and Gli are also detected on the promoters of Hh targets in a dynamic manner. Our results support a new model of Hh signaling in the nucleus. Sufu recruits p66β to block Gli-mediated Hh target gene expression. Meanwhile, Mycbp forms a complex with Gli and Sufu without Hh stimulation but remains inactive. Hh pathway activation leads to dissociation of Sufu/p66β from Gli, enabling Mycbp to promote Gli protein activity and Hh target gene expression. These studies provide novel insight into how Sufu controls Hh signaling in the nucleus.
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Affiliation(s)
- Chuwen Lin
- Cardiovascular Research Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Erica Yao
- Cardiovascular Research Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Kevin Wang
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Yoko Nozawa
- Cardiovascular Research Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Hirohito Shimizu
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Jeffrey R Johnson
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158
| | - Jau-Nian Chen
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158
| | - Pao-Tien Chuang
- Cardiovascular Research Institute, University of California at San Francisco, San Francisco, California 94158, USA;
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120
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Blaess S, Szabó N, Haddad-Tóvolli R, Zhou X, Álvarez-Bolado G. Sonic hedgehog signaling in the development of the mouse hypothalamus. Front Neuroanat 2015; 8:156. [PMID: 25610374 PMCID: PMC4285088 DOI: 10.3389/fnana.2014.00156] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/02/2014] [Indexed: 11/13/2022] Open
Abstract
The expression pattern of Sonic Hedgehog (Shh) in the developing hypothalamus changes over time. Shh is initially expressed in the prechordal mesoderm and later in the hypothalamic neuroepithelium—first medially, and then in two off-medial domains. This dynamic expression suggests that Shh might regulate several aspects of hypothalamic development. To gain insight into them, lineage tracing, (conditional) gene inactivation in mouse, in ovo loss- and gain-of-function approaches in chick and analysis of Shh expression regulation have been employed. We will focus on mouse studies and refer to chick and fish when appropriate to clarify. These studies show that Shh-expressing neuroepithelial cells serve as a signaling center for neighboring precursors, and give rise to most of the basal hypothalamus (tuberal and mammillary regions). Shh signaling is initially essential for hypothalamic induction. Later, Shh signaling from the neuroepithelium controls specification of the lateral hypothalamic area and growth-patterning coordination in the basal hypothalamus. To further elucidate the role of Shh in hypothalamic development, it will be essential to understand how Shh regulates the downstream Gli transcription factors.
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Affiliation(s)
- Sandra Blaess
- Neurodevelopmental Genetics, Institute of Reconstructive Neurobiology, University of Bonn Bonn, Germany
| | - Nora Szabó
- Department of Neurobiology and Development, Institut de Recherches Cliniques de Montréal Montréal, QC, Canada
| | - Roberta Haddad-Tóvolli
- Department of Medical Cell Biology, Institute of Anatomy and Cell Biology, University of Heidelberg Heidelberg, Germany
| | - Xunlei Zhou
- Department of Medical Cell Biology, Institute of Anatomy and Cell Biology, University of Heidelberg Heidelberg, Germany
| | - Gonzalo Álvarez-Bolado
- Department of Medical Cell Biology, Institute of Anatomy and Cell Biology, University of Heidelberg Heidelberg, Germany
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121
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Liu YC, Couzens AL, Deshwar AR, B McBroom-Cerajewski LD, Zhang X, Puviindran V, Scott IC, Gingras AC, Hui CC, Angers S. The PPFIA1-PP2A protein complex promotes trafficking of Kif7 to the ciliary tip and Hedgehog signaling. Sci Signal 2014; 7:ra117. [PMID: 25492966 DOI: 10.1126/scisignal.2005608] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The primary cilium is required for Hedgehog (Hh) signaling in vertebrates. Hh leads to ciliary accumulation and activation of the transmembrane protein Smoothened (Smo) and affects the localization of several pathway components, including the Gli family of transcriptional regulators, within different regions of primary cilia. Genetic analysis indicates that the kinesin protein Kif7 both promotes and inhibits mouse Hh signaling. Using mass spectrometry, we identified liprin-α1 (PPFIA1) and the protein phosphatase PP2A as Kif7-interacting proteins, and we showed that they were important for the trafficking of Kif7 and Gli proteins to the tips of cilia and for the transcriptional output of Hh signaling. Our results suggested that PPFIA1 functioned with PP2A to promote the dephosphorylation of Kif7, triggering Kif7 localization to the tips of primary cilia and promoting Gli transcriptional activity.
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Affiliation(s)
- Yulu C Liu
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Amber L Couzens
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Ashish R Deshwar
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | | | - Xiaoyun Zhang
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Vijitha Puviindran
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Ian C Scott
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada. Program in Developmental and Stem Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada. Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Chi-Chung Hui
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada. Program in Developmental and Stem Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Stephane Angers
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada. Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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122
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A function for the Joubert syndrome protein Arl13b in ciliary membrane extension and ciliary length regulation. Dev Biol 2014; 397:225-36. [PMID: 25448689 DOI: 10.1016/j.ydbio.2014.11.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 10/31/2014] [Accepted: 11/11/2014] [Indexed: 11/20/2022]
Abstract
Cilia perform a variety of functions in a number of developmental and physiological contexts, and are implicated in the pathogenesis of a wide spectrum of human disorders. While the ciliary axoneme is assembled by intraflagellar transport, how ciliary membrane length is regulated is not completely understood. Here, we show that zebrafish embryos as well as mammalian cells overexpressing the ciliary membrane protein Arl13b, an ARF family small GTPase that is essential for ciliary differentiation, showed pronounced increase in ciliary length. Intriguingly, this increase in cilia length occurred as a function of the amounts of overexpressed Arl13b. While the motility of Arl13b overexpressing excessively long motile cilia was obviously disrupted, surprisingly, the abnormally long immotile primary cilia seemed to retain their signaling capacity. arl13b is induced by FoxJ1 and Rfx, and these ciliogenic transcription factors are unable to promote ciliary length increase when Arl13b activity is inhibited. Conversely, overexpression of Arl13b was sufficient to restore ciliary length in zebrafish embryos deficient in FoxJ1 function. We show that Arl13b increases cilia length by inducing protrusion of the ciliary membrane, which is then followed by the extension of the axonemal microtubules. Using mutant versions of Arl13b, one of which has been shown to be causative of the ciliopathy Joubert syndrome, we establish that the GTPase activity of the protein is essential for ciliary membrane extension. Taken together, our findings identify Arl13b as an important effector of ciliary membrane biogenesis and ciliary length regulation, and provide insights into possible mechanisms of dysfunction of the protein in Joubert syndrome.
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Rajurkar M, Huang H, Cotton JL, Brooks JK, Sicklick J, McMahon AP, Mao J. Distinct cellular origin and genetic requirement of Hedgehog-Gli in postnatal rhabdomyosarcoma genesis. Oncogene 2014; 33:5370-8. [PMID: 24276242 PMCID: PMC4309268 DOI: 10.1038/onc.2013.480] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 09/09/2013] [Accepted: 09/24/2013] [Indexed: 12/20/2022]
Abstract
Dysregulation of the Hedgehog (Hh)-Gli signaling pathway is implicated in a variety of human cancers, including basal cell carcinoma (BCC), medulloblastoma (MB) and embryonal rhabdhomyosarcoma (eRMS), three principle tumors associated with human Gorlin syndrome. However, the cells of origin of these tumors, including eRMS, remain poorly understood. In this study, we explore the cell populations that give rise to Hh-related tumors by specifically activating Smoothened (Smo) in both Hh-producing and -responsive cell lineages in postnatal mice. Interestingly, we find that unlike BCC and MB, eRMS originates from the stem/progenitor populations that do not normally receive active Hh signaling. Furthermore, we find that the myogenic lineage in postnatal mice is largely Hh quiescent and that Pax7-expressing muscle satellite cells are not able to give rise to eRMS upon Smo or Gli1/2 overactivation in vivo, suggesting that Hh-induced skeletal muscle eRMS arises from Hh/Gli quiescent non-myogenic cells. In addition, using the Gli1 null allele and a Gli3 repressor allele, we reveal a specific genetic requirement for Gli proteins in Hh-induced eRMS formation and provide molecular evidence for the involvement of Sox4/11 in eRMS cell survival and differentiation.
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Affiliation(s)
- Mihir Rajurkar
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605
| | - He Huang
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605
- Department of Histology & Embryology, Xiangya School of Medicine, Central South University, Changsha, P.R. China
| | - Jennifer L. Cotton
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Julie K. Brooks
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Jason Sicklick
- Division of Surgical Oncology, Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093
| | - Andrew P. McMahon
- Department of Stem Cell Biology and Regenerative Medicine, Broad-CIRM Center for Regenerative Medicine and Stem Cell Research, WM Keck School of Medicine of the University of Southern California, Los Angeles, CA 90015
| | - Junhao Mao
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605
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Swartling FJ, Bolin S, Phillips JJ, Persson AI. Signals that regulate the oncogenic fate of neural stem cells and progenitors. Exp Neurol 2014; 260:56-68. [PMID: 23376224 PMCID: PMC3758390 DOI: 10.1016/j.expneurol.2013.01.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 01/19/2013] [Accepted: 01/24/2013] [Indexed: 12/16/2022]
Abstract
Brain tumors have frequently been associated with a neural stem cell (NSC) origin and contain stem-like tumor cells, so-called brain tumor stem cells (BTSCs) that share many features with normal NSCs. A stem cell state of BTSCs confers resistance to radiotherapy and treatment with alkylating agents. It is also a hallmark of aggressive brain tumors and is maintained by transcriptional networks that are also active in embryonic stem cells. Advances in reprogramming of somatic cells into induced pluripotent stem (iPS) cells have further identified genes that drive stemness. In this review, we will highlight the possible drivers of stemness in medulloblastoma and glioma, the most frequent types of primary malignant brain cancer in children and adults, respectively. Signals that drive expansion of developmentally defined neural precursor cells are also active in corresponding brain tumors. Transcriptomal subgroups of human medulloblastoma and glioma match features of NSCs but also more restricted progenitors. Lessons from genetically-engineered mouse (GEM) models show that temporally and regionally defined NSCs can give rise to distinct subgroups of medulloblastoma and glioma. We will further discuss how acquisition of stem cell features may drive brain tumorigenesis from a non-NSC origin. Genetic alterations, signaling pathways, and therapy-induced changes in the tumor microenvironment can drive reprogramming networks and induce stemness in brain tumors. Finally, we propose a model where dysregulation of microRNAs (miRNAs) that normally provide barriers against reprogramming plays an integral role in promoting stemness in brain tumors.
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Affiliation(s)
- Fredrik J Swartling
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Sara Bolin
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Joanna J Phillips
- Department of Neurological Surgery, Brain Tumor Research Center, University of California, San Francisco, USA; Department of Pathology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, USA
| | - Anders I Persson
- Department of Neurological Surgery, Brain Tumor Research Center, University of California, San Francisco, USA; Department of Neurology, Sandler Neurosciences Center, University of California, San Francisco, USA.
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125
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Colavito SA, Zou MR, Yan Q, Nguyen DX, Stern DF. Significance of glioma-associated oncogene homolog 1 (GLI1) expression in claudin-low breast cancer and crosstalk with the nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) pathway. Breast Cancer Res 2014; 16:444. [PMID: 25252859 PMCID: PMC4303124 DOI: 10.1186/s13058-014-0444-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 09/08/2014] [Indexed: 01/07/2023] Open
Abstract
Introduction The recently identified claudin-low subtype of breast cancer is enriched for cells with stem-like and mesenchymal-like characteristics. This subtype is most often triple-negative (lacking the estrogen and progesterone receptors (ER, PR) as well as lacking epidermal growth factor 2 (HER2) amplification) and has a poor prognosis. There are few targeted treatment options available for patients with this highly aggressive type of cancer. Methods Using a high throughput inhibitor screen, we identified high expression of glioma-associated oncogene homolog 1 (GLI1), the effector molecule of the hedgehog (Hh) pathway, as a critical determinant of cell lines that have undergone an epithelial to mesenchymal transition (EMT). Results High GLI1 expression is a property of claudin-low cells and tumors and correlates with markers of EMT and breast cancer stem cells. Knockdown of GLI1 expression in claudin-low cell lines resulted in reduced cell viability, motility, clonogenicity, self-renewal, and reduced tumor growth of orthotopic xenografts. We observed non-canonical activation of GLI1 in claudin-low and EMT cell lines, and identified crosstalk with the NFκB pathway. Conclusions This work highlights the importance of GLI1 in the maintenance of characteristics of metastatic breast cancer stem cells. Remarkably, treatment with an inhibitor of the NFκB pathway reproducibly reduces GLI1 expression and protein levels. We further provide direct evidence for the binding of the NFκB subunit p65 to the GLI1 promoter in both EMT and claudin-low cell lines. Our results uncover crosstalk between NFκB and GLI1 signals and suggest that targeting these pathways may be effective against the claudin-low breast cancer subtype. Electronic supplementary material The online version of this article (doi:10.1186/s13058-014-0444-4) contains supplementary material, which is available to authorized users.
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126
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Hede SM, Savov V, Weishaupt H, Sangfelt O, Swartling FJ. Oncoprotein stabilization in brain tumors. Oncogene 2014; 33:4709-21. [PMID: 24166497 DOI: 10.1038/onc.2013.445] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 09/11/2013] [Accepted: 09/12/2013] [Indexed: 12/12/2022]
Abstract
Proteins involved in promoting cell proliferation and viability need to be timely expressed and carefully controlled for the proper development of the brain but also efficiently degraded in order to prevent cells from becoming brain cancer cells. A major pathway for targeted protein degradation in cells is the ubiquitin-proteasome system (UPS). Oncoproteins that drive tumor development and tumor maintenance are often deregulated and stabilized in malignant cells. This can occur when oncoproteins escape degradation by the UPS because of mutations in either the oncoprotein itself or in the UPS components responsible for recognition and ubiquitylation of the oncoprotein. As the pathogenic accumulation of an oncoprotein can lead to effectively sustained cell growth, viability and tumor progression, it is an indisputable target for cancer treatment. The most common types of malignant brain tumors in children and adults are medulloblastoma and glioma, respectively. Here, we review different ways of how deregulated proteolysis of oncoproteins involved in major signaling cancer pathways contributes to medulloblastoma and glioma development. We also describe means of targeting relevant oncoproteins in brain tumors with treatments affecting their stability or therapeutic strategies directed against the UPS itself.
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Affiliation(s)
- S-M Hede
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - V Savov
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - H Weishaupt
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - O Sangfelt
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - F J Swartling
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
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Aberger F, Ruiz i Altaba A. Context-dependent signal integration by the GLI code: the oncogenic load, pathways, modifiers and implications for cancer therapy. Semin Cell Dev Biol 2014; 33:93-104. [PMID: 24852887 PMCID: PMC4151135 DOI: 10.1016/j.semcdb.2014.05.003] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/12/2014] [Indexed: 01/10/2023]
Abstract
Canonical Hedgehog (HH) signaling leads to the regulation of the GLI code: the sum of all positive and negative functions of all GLI proteins. In humans, the three GLI factors encode context-dependent activities with GLI1 being mostly an activator and GLI3 often a repressor. Modulation of GLI activity occurs at multiple levels, including by co-factors and by direct modification of GLI structure. Surprisingly, the GLI proteins, and thus the GLI code, is also regulated by multiple inputs beyond HH signaling. In normal development and homeostasis these include a multitude of signaling pathways that regulate proto-oncogenes, which boost positive GLI function, as well as tumor suppressors, which restrict positive GLI activity. In cancer, the acquisition of oncogenic mutations and the loss of tumor suppressors - the oncogenic load - regulates the GLI code toward progressively more activating states. The fine and reversible balance of GLI activating GLI(A) and GLI repressing GLI(R) states is lost in cancer. Here, the acquisition of GLI(A) levels above a given threshold is predicted to lead to advanced malignant stages. In this review we highlight the concepts of the GLI code, the oncogenic load, the context-dependency of GLI action, and different modes of signaling integration such as that of HH and EGF. Targeting the GLI code directly or indirectly promises therapeutic benefits beyond the direct blockade of individual pathways.
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Affiliation(s)
- Fritz Aberger
- Department of Molecular Biology, University of Salzburg, Hellbrunner Strasse 34, 5020 Salzburg, Austria.
| | - Ariel Ruiz i Altaba
- Department of Genetic Medicine and Development, University of Geneva Medical School, 8242 CMU, 1 rue Michel Servet, CH-1211 Geneva, Switzerland.
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Caballero IM, Manuel MN, Molinek M, Quintana-Urzainqui I, Mi D, Shimogori T, Price DJ. Cell-autonomous repression of Shh by transcription factor Pax6 regulates diencephalic patterning by controlling the central diencephalic organizer. Cell Rep 2014; 8:1405-18. [PMID: 25176648 PMCID: PMC4241467 DOI: 10.1016/j.celrep.2014.07.051] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 06/24/2014] [Accepted: 07/27/2014] [Indexed: 11/17/2022] Open
Abstract
During development, region-specific patterns of regulatory gene expression are controlled by signaling centers that release morphogens providing positional information to surrounding cells. Regulation of signaling centers themselves is therefore critical. The size and the influence of a Shh-producing forebrain organizer, the zona limitans intrathalamica (ZLI), are limited by Pax6. By studying mouse chimeras, we find that Pax6 acts cell autonomously to block Shh expression in cells around the ZLI. Immunoprecipitation and luciferase assays indicate that Pax6 can bind the Shh promoter and repress its function. An analysis of chimeras suggests that many of the regional gene expression pattern defects that occur in Pax6−/− diencephalic cells result from a non-cell-autonomous position-dependent defect of local intercellular signaling. Blocking Shh signaling in Pax6−/− mutants reverses major diencephalic patterning defects. We conclude that Pax6’s cell-autonomous repression of Shh expression around the ZLI is critical for many aspects of normal diencephalic patterning. Pax6 limits the effects of a forebrain organizer, the zona limitans intrathalamica Pax6 blocks diencephalic Shh expression cell autonomously Absence of Pax6 causes non-cell-autonomous diencephalic patterning defects Blocking Shh signaling in Pax6−/− mutants reverses diencephalic patterning defects
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Affiliation(s)
| | - Martine N Manuel
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Michael Molinek
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | | | - Da Mi
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | | | - David J Price
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK.
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Roque-Ramírez B, Chimal-Monroy J, Canto P, Coral-Vázquez RM. Expression pattern of mRNA A and mRNA B of alpha sarcoglycan gene during mouse embryonic development and regulation of their expression by myogenic and cardiogenic transcription factors. Dev Dyn 2014; 243:1416-28. [PMID: 25091331 DOI: 10.1002/dvdy.24175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 06/26/2014] [Accepted: 07/17/2014] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Type 2D limb-girdle muscular dystrophy (LGM2D) is a progressive disorder caused by mutations in the alpha sarcoglycan (α-SG) gene. In mice, the α-SG gene contains two promoters that regulate the expression of two different mRNAs (A and B). However, their gene expression pattern during embryonic development has not been explored and their regulation by myogenic and cardiogenic transcription factors has been only partially studied. RESULTS During embryonic development, mRNA A and B of α-SG gene were initially detected in hypaxial muscles, heart, stomach, tongue, and mesenchymal cells, which surround the dorsal region of the somites. Moreover, mRNA B was exclusively expressed in the floor plate and notochord and in the interdigits of limbs. In vitro, MyoD and myogenin positively regulated the transcription of mRNA B during skeletal myogenesis, whereas mRNA A was activated only for MyoD in differentiated skeletal muscle. In addition, Gata-4 together with Mef2c may regulate the expression of mRNA B in heart development, whereas Nkx2.5 and myocardin may activate expression of mRNA A in the differentiated cardiomyocyte. CONCLUSIONS The differential expression of α-SG mRNAs during mouse embryonic development may be a consequence of the differential regulation of both promoters by myogenic and cardiogenic factors.
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Affiliation(s)
- Bladimir Roque-Ramírez
- División de Investigación Biomédica, Subdirección de Enseñanza e Investigación, Centro Médico Nacional 20 de Noviembre, Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado, México, D.F. México
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Aguila JC, Blak A, van Arensbergen J, Sousa A, Vázquez N, Aduriz A, Gayosso M, Lopez Mato MP, Lopez de Maturana R, Hedlund E, Sonntag KC, Sanchez-Pernaute R. Selection Based on FOXA2 Expression Is Not Sufficient to Enrich for Dopamine Neurons From Human Pluripotent Stem Cells. Stem Cells Transl Med 2014; 3:1032-42. [PMID: 25024431 DOI: 10.5966/sctm.2014-0011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Human embryonic and induced pluripotent stem cells are potential cell sources for regenerative approaches in Parkinson disease. Inductive differentiation protocols can generate midbrain dopamine neurons but result in heterogeneous cell mixtures. Therefore, selection strategies are necessary to obtain uniform dopamine cell populations. Here, we developed a selection approach using lentivirus vectors to express green fluorescent protein under the promoter region of FOXA2, a transcription factor that is expressed in the floor plate domain that gives rise to dopamine neurons during embryogenesis. We first validated the specificity of the vectors in human cell lines against a promoterless construct. We then selected FOXA2-positive neural progenitors from several human pluripotent stem cell lines, which demonstrated a gene expression profile typical for the ventral domain of the midbrain and floor plate, but failed to enrich for dopamine neurons. To investigate whether this was due to the selection approach, we overexpressed FOXA2 in neural progenitors derived from human pluripotent stem cell lines. FOXA2 forced expression resulted in an increased expression of floor plate but not mature neuronal markers. Furthermore, selection of the FOXA2 overexpressing fraction also failed to enrich for dopamine neurons. Collectively, our results suggest that FOXA2 is not sufficient to induce a dopaminergic fate in this system. On the other hand, our study demonstrates that a combined approach of promoter activation and lentivirus vector technology can be used as a versatile tool for the selection of a defined cell population from a variety of human pluripotent stem cell lines.
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Affiliation(s)
- Julio Cesar Aguila
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Alexandra Blak
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Joris van Arensbergen
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Amaia Sousa
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Nerea Vázquez
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Ariane Aduriz
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Mayela Gayosso
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Maria Paz Lopez Mato
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Rakel Lopez de Maturana
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Eva Hedlund
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Kai-Christian Sonntag
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
| | - Rosario Sanchez-Pernaute
- Laboratory of Stem Cells and Neural Repair and Cytometry and Advanced Optical Microscopy Facility, Inbiomed, San Sebastian, Spain; STEMCELL Technologies, Inc., Vancouver, British Columbia, Canada; Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, USA
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Sverrisson EF, Zens MS, Fei DL, Andrews A, Schned A, Robbins D, Kelsey KT, Li H, DiRenzo J, Karagas MR, Seigne JD. Clinicopathological correlates of Gli1 expression in a population-based cohort of patients with newly diagnosed bladder cancer. Urol Oncol 2014; 32:539-45. [PMID: 24856810 PMCID: PMC4243987 DOI: 10.1016/j.urolonc.2014.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 03/01/2014] [Accepted: 03/03/2014] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Dysregulation of the hedgehog signaling pathway has been linked to the development and progression of a variety of different human tumors including cancers of the skin, brain, colon, prostate, blood, and pancreas. We assessed the clinicopathological factors that are potentially related to expression of Gli1, the transcription factor that is thought to be the most reliable marker of hedgehog pathway activation in bladder cancer. METHODS Bladder cancer cases were identified from the New Hampshire State Cancer Registry as histologically confirmed primary bladder cancer diagnosed between January 1, 2002, and July 31, 2004. Immunohistochemical analysis was performed on a tissue microarray to detect Gli1 and p53 expression in these bladder tumors. We computed odds ratios (ORs) and their 95% CIs for Gli1 positivity for pathological category using T category (from TNM), invasiveness, and grade with both the World Health Organization 1973 and World Health Organization International Society of Urological Pathology criteria. We calculated hazard ratios and their 95% CI for Gli1 positivity and recurrence for both Ta-category and invasive bladder tumors (T1+). RESULTS A total of 194 men and 67 women, whose tumors were assessable for Gli1 staining, were included in the study. No appreciable differences in Gli1 staining were noted by sex, age, smoking status, or high-risk occupation. Ta-category tumors were more likely to stain for Gli1 as compared with T1-category tumors (adjusted OR = 0.38, CI: 0.17-0.87). Similarly, low-grade (grades 1-2) tumors were more likely to stain for Gli1 as compared with high-grade tumors (grade 3) (adjusted OR = 0.44, CI: 0.21-0.93). In a Cox proportional hazards regression analysis, non-muscle-invasive bladder tumors expressing Gli1 were less likely to recur (adjusted hazard ratio = 0.48; CI: 0.28-0.82; P<0.05) than those in which Gli1 was absent. CONCLUSION Our findings indicate that Gli1 expression may be a marker of low-stage, low-grade bladder tumors and an indicator of a reduced risk of recurrence in this group.
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Affiliation(s)
- Einar F Sverrisson
- Department of Surgery (Urology), Dartmouth-Hitchcock Medical Center, Lebanon, NH
| | - Michael S Zens
- Department of Community and Family Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Dennis Liang Fei
- Cancer Biology Section, National Institutes of Health, Bethesda, MD
| | - Angeline Andrews
- Department of Community and Family Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Alan Schned
- Department of Pathology (Urology), Dartmouth-Hitchcock Medical Center, Lebanon, NH
| | - David Robbins
- Molecular Oncology Program, Department of Surgery, University of Miami, Miami, FL
| | - Karl T Kelsey
- Department of Community Health, Brown University, Providence, RI
| | - Hua Li
- Center for Prostate Disease Research, Uniformed Services University of the Health Sciences, Bethesda, MD
| | - James DiRenzo
- Department of Pharmacology and Toxicology, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Margaret R Karagas
- Department of Community and Family Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - John D Seigne
- Department of Surgery (Urology), Dartmouth-Hitchcock Medical Center, Lebanon, NH.
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Hwang SH, Mukhopadhyay S. G-protein-coupled receptors and localized signaling in the primary cilium during ventral neural tube patterning. ACTA ACUST UNITED AC 2014; 103:12-9. [PMID: 24917297 DOI: 10.1002/bdra.23267] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 05/06/2014] [Accepted: 05/19/2014] [Indexed: 01/04/2023]
Abstract
The primary cilium is critical in sonic hedgehog (Shh)-dependent ventral patterning of the vertebrate neural tube. Most mutants that cause disruption of the cilium result in decreased Shh signaling in the neural tube. In contrast, mutations in the intraflagellar complex A (IFT-A) and the tubby family protein, Tulp3, result in increased Shh signaling in the neural tube. Proteomic analysis of Tulp3-binding proteins first pointed to the role of the IFT-A complex in trafficking Tulp3 into the cilia. Tulp3 directs trafficking of rhodopsin family G-protein-coupled receptors (GPCRs) to the cilia, suggesting the role of a GPCR in mediating the paradoxical effects of the Tulp3/IFT-A complex in causing increased Shh signaling. Gpr161 has recently been identified as a Tulp3/IFT-A-regulated GPCR that localizes to the primary cilium. A null knock-out mouse model of Gpr161 phenocopies Tulp3 and IFT-A mutants, and causes increased Shh signaling throughout the neural tube. In the absence of Shh, the bifunctional Gli transcription factors are proteolytically processed into repressor forms in a protein kinase A (PKA) -dependent and cilium-dependent manner. Gpr161 activity results in increased cAMP levels in a Gαs -coupled manner, and determines processing of Gli3. Shh signaling also results in removal of Gpr161 from the cilia, suggesting that Gpr161 functions in a positive feedback loop in the Shh pathway. As PKA-null and Gαs mutant embryos also exhibit increased Shh signaling in the neural tube, Gpr161 is a strong candidate for a GPCR that regulates ciliary cAMP levels, and activates PKA in close proximity to the cilia.
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Affiliation(s)
- Sun-Hee Hwang
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas
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Liu Y, Wei Z, Huang Y, Bai C, Zan L, Li G. Cyclopamine did not affect mouse oocyte maturation in vitro but decreased early embryonic development. Anim Sci J 2014; 85:840-7. [PMID: 24889396 DOI: 10.1111/asj.12220] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 01/30/2014] [Indexed: 12/31/2022]
Abstract
Hedgehog (Hh) pathway has been studied in various animal body life procedures and is suggested to be important for the development of multiple organs. The genes involved in the Hh signaling pathway were expressed in the ovary of mice, pigs and cattle. However, the function of Hh signaling pathway on oocyte maturation and early embryonic development is still controversial. We detected the effect of sonic hedgehog (Shh) and cyclopamine on the in vitro maturation of mouse oocytes and embryo development. The results showed that the presence of Shh or cyclopamine resulted in similar oocyte maturation to control groups. Shh did not improve early embryonic development. However, the supplement of cyclopamine depressed early embryo development. The mRNA of shh, ptch1, smo and gli1 were less detected in the denuded oocytes. The expression levels of ptch1 ascended from the uncleaved zygote to blastocyst stage. Smo or gli1 were expressed on a higher level at the two-cell or four-cell stage in early embryonic development separately. Therefore, Shh did not affect mouse oocyte maturation and early embryo development, but cyclopamine led to inhibited development of mouse early embryo. The effects of Hh signaling on the oocyte maturation and early embryo development might be species-specific.
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Affiliation(s)
- Yang Liu
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
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134
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G-protein-coupled receptors, Hedgehog signaling and primary cilia. Semin Cell Dev Biol 2014; 33:63-72. [PMID: 24845016 DOI: 10.1016/j.semcdb.2014.05.002] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/12/2014] [Indexed: 12/21/2022]
Abstract
The Hedgehog (Hh) pathway has become an important model to study the cell biology of primary cilia, and reciprocally, the study of ciliary processes provides an opportunity to solve longstanding mysteries in the mechanism of vertebrate Hh signal transduction. The cilium is emerging as an unique compartment for G-protein-coupled receptor (GPCR) signaling in many systems. Two members of the GPCR family, Smoothened and Gpr161, play important roles in the Hh pathway. We review the current understanding of how these proteins may function to regulate Hh signaling and also highlight some of the critical unanswered questions being tackled by the field. Uncovering GPCR-regulated mechanisms important in Hh signaling may provide therapeutic strategies against the Hh pathway that plays important roles in development, regeneration and cancer.
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135
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Shahi MH, Holt R, Rebhun RB. Blocking signaling at the level of GLI regulates downstream gene expression and inhibits proliferation of canine osteosarcoma cells. PLoS One 2014; 9:e96593. [PMID: 24810746 PMCID: PMC4014515 DOI: 10.1371/journal.pone.0096593] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 04/09/2014] [Indexed: 01/26/2023] Open
Abstract
The Hedgehog-GLI signaling pathway is active in a variety of human malignancies and is known to contribute to the growth and survival of human osteosarcoma cells. In this study, we examined the expression and regulation of GLI transcription factors in multiple canine osteosarcoma cell lines and analyzed the effects of inhibiting GLI with GANT61, a GLI-specific inhibitor. Compared with normal canine osteoblasts, real-time PCR showed that GLI1 and GLI2 were highly expressed in two out of three cell lines and correlated with downstream target gene expression of PTCH1and PAX6. Treatment of canine osteosarcoma cells with GANT61 resulted in decreased expression of GLI1, GLI2, PTCH1, and PAX6. Furthermore, GANT61 inhibited proliferation and colony formation in all three canine osteosarcoma cell lines. The finding that GLI signaling activity is present and active in canine osteosarcoma cells suggests that spontaneously arising osteosarcoma in dogs might serve as a good model for future preclinical testing of GLI inhibitors.
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Affiliation(s)
- Mehdi Hayat Shahi
- The Department of Surgical and Radiological Sciences, University of California Davis School of Veterinary Medicine, Davis, California, United States of America
| | - Roseline Holt
- The Department of Surgical and Radiological Sciences, University of California Davis School of Veterinary Medicine, Davis, California, United States of America
| | - Robert B. Rebhun
- The Department of Surgical and Radiological Sciences, University of California Davis School of Veterinary Medicine, Davis, California, United States of America
- * E-mail:
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136
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Down-regulation of Gli-1 inhibits hepatocellular carcinoma cell migration and invasion. Mol Cell Biochem 2014; 393:283-91. [PMID: 24792036 DOI: 10.1007/s11010-014-2071-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/12/2014] [Indexed: 01/11/2023]
Abstract
Glioma-associated oncogene homolog-1 (Gli-1) is considered a marker of Hedgehog pathway activation and is associated with the progression of several cancers. We have previously reported that Gli-1 was correlated with invasion and metastasis in hepatocellular carcinoma (HCC). However, the exact roles and mechanisms of Gli-1 in HCC invasion are unclear. In this study, we found that small interfering RNA mediated down-regulation of Gli-1 expression significantly suppressed adhesion, motility, migration, and invasion of both SMMC-7721 and SK-Hep1 cells. Furthermore, down-regulation of Gli-1 significantly reduced expressions and activities of both matrix metalloproteinase (MMP)-2 and MMP-9. In addition, we found that down-regulation of Gli-1 resulted in up-regulation of E-cadherin and concomitant down-regulation of Snail and Vimentin, consistent with inhibition of epithelial-mesenchymal transition (EMT). Taken together, our results suggest that down-regulation of Gli-1 suppresses HCC cell migration and invasion likely through inhibiting expressions and activations of MMP-2, 9 and blocking EMT.
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137
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Santini R, Pietrobono S, Pandolfi S, Montagnani V, D'Amico M, Penachioni JY, Vinci MC, Borgognoni L, Stecca B. SOX2 regulates self-renewal and tumorigenicity of human melanoma-initiating cells. Oncogene 2014; 33:4697-708. [PMID: 24681955 PMCID: PMC4180644 DOI: 10.1038/onc.2014.71] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 02/13/2014] [Accepted: 02/17/2014] [Indexed: 02/06/2023]
Abstract
Melanoma is one of the most aggressive types of human cancer, characterized by enhanced heterogeneity and resistance to conventional therapy at advanced stages. We and others have previously shown that HEDGEHOG-GLI (HH-GLI) signaling is required for melanoma growth and for survival and expansion of melanoma-initiating cells (MICs). Recent reports indicate that HH-GLI signaling regulates a set of genes typically expressed in embryonic stem cells, including SOX2 (sex-determining region Y (SRY)-Box2). Here we address the function of SOX2 in human melanomas and MICs and its interaction with HH-GLI signaling. We find that SOX2 is highly expressed in melanoma stem cells. Knockdown of SOX2 sharply decreases self-renewal in melanoma spheres and in putative melanoma stem cells with high aldehyde dehydrogenase activity (ALDH(high)). Conversely, ectopic expression of SOX2 in melanoma cells enhances their self-renewal in vitro. SOX2 silencing also inhibits cell growth and induces apoptosis in melanoma cells. In addition, depletion of SOX2 progressively abrogates tumor growth and leads to a significant decrease in tumor-initiating capability of ALDH(high) MICs upon xenotransplantation, suggesting that SOX2 is required for tumor initiation and for continuous tumor growth. We show that SOX2 is regulated by HH signaling and that the transcription factors GLI1 and GLI2, the downstream effectors of HH-GLI signaling, bind to the proximal promoter region of SOX2 in primary melanoma cells. In functional studies, we find that SOX2 function is required for HH-induced melanoma cell growth and MIC self-renewal in vitro. Thus SOX2 is a critical factor for self-renewal and tumorigenicity of MICs and an important mediator of HH-GLI signaling in melanoma. These findings could provide the basis for novel therapeutic strategies based on the inhibition of SOX2 for the treatment of a subset of human melanomas.
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Affiliation(s)
- R Santini
- Laboratory of Tumor Cell Biology, Core Research Laboratory-Istituto Toscano Tumori (CRL-ITT), Florence, Italy
| | - S Pietrobono
- Laboratory of Tumor Cell Biology, Core Research Laboratory-Istituto Toscano Tumori (CRL-ITT), Florence, Italy
| | - S Pandolfi
- Laboratory of Tumor Cell Biology, Core Research Laboratory-Istituto Toscano Tumori (CRL-ITT), Florence, Italy
| | - V Montagnani
- Laboratory of Tumor Cell Biology, Core Research Laboratory-Istituto Toscano Tumori (CRL-ITT), Florence, Italy
| | - M D'Amico
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - J Y Penachioni
- Laboratory of Tumor Cell Biology, Core Research Laboratory-Istituto Toscano Tumori (CRL-ITT), Florence, Italy
| | - M C Vinci
- Laboratory of Tumor Cell Biology, Core Research Laboratory-Istituto Toscano Tumori (CRL-ITT), Florence, Italy
| | - L Borgognoni
- Plastic Surgery Unit, S.M. Annunziata Hospital-Regional Melanoma Referral Center, Istituto Toscano Tumori, Florence, Italy
| | - B Stecca
- Laboratory of Tumor Cell Biology, Core Research Laboratory-Istituto Toscano Tumori (CRL-ITT), Florence, Italy
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Harvey MC, Fleet A, Okolowsky N, Hamel PA. Distinct effects of the mesenchymal dysplasia gene variant of murine Patched-1 protein on canonical and non-canonical Hedgehog signaling pathways. J Biol Chem 2014; 289:10939-10949. [PMID: 24570001 DOI: 10.1074/jbc.m113.514844] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Hedgehog (Hh) signaling requires regulation of the receptor Patched-1 (Ptch1), which, in turn, regulates Smoothened activity (canonical Hh signaling) as well as other non-canonical signaling pathways. The mutant Ptch1 allele mesenchymal dysplasia (mes), which truncates the Ptch1 C terminus, produces a limited spectrum of developmental defects in mice as well as deregulation of canonical Hh signaling in some, but not all, affected tissues. Paradoxically, mes suppresses canonical Hh signaling and binds to Hh ligands with an affinity similar to wild-type mouse Ptch1 (mPtch1). We characterized the distinct activities of the mes variant of mPtch1 mediating Hh signaling through both canonical and non-canonical pathways. We demonstrated that mPtch1 bound c-src in an Hh-regulated manner. Stimulation with Sonic Hedgehog (Shh) of primary mammary mesenchymal cells from wild-type and mes animals activated Erk1/2. Although Shh activated c-src in wild-type cells, c-src was constitutively activated in mes mesenchymal cells. Transient assays showed that wild-type mPtch1, mes, or mPtch1 lacking the C terminus repressed Hh signaling in Ptch1-deficient mouse embryo fibroblasts and that repression was reversed by Shh, revealing that the C terminus was dispensable for mPtch1-dependent regulation of canonical Hh signaling. In contrast to these transient assays, constitutively high levels of mGli1 but not mPtch1 were present in primary mammary mesenchymal cells from mes mice, whereas the expression of mPtch1 was similarly induced in both mes and wild-type cells. These data define a novel signal transduction pathway involving c-src that is activated by the Hh ligands and reveals the requirement for the C terminus of Ptch in regulation of canonical and non-canonical Hh signaling pathways.
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Affiliation(s)
- Malcolm C Harvey
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Andrew Fleet
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Nadia Okolowsky
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Paul A Hamel
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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139
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Zhao Y, Huang J, Zhang L, Qu Y, Li J, Yu B, Yan M, Yu Y, Liu B, Zhu Z. MiR-133b is frequently decreased in gastric cancer and its overexpression reduces the metastatic potential of gastric cancer cells. BMC Cancer 2014; 14:34. [PMID: 24443799 PMCID: PMC3925791 DOI: 10.1186/1471-2407-14-34] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 01/16/2014] [Indexed: 12/18/2022] Open
Abstract
Background Emerging evidence has shown that microRNAs are involved in gastric cancer development and progression. Here we examine the role of miR-133b in gastric cancer. Methods Quantitative real-time PCR analysis was performed in 140 patient gastric cancer tissues and 8 gastric cancer cell lines. The effects of miR-133b in gastric cancer cells metastasis were examined by scratch assay, transwell migration and matrigel invasion. In vivo effects of miR-133b were examined in an intraperitoneal mouse tumor model. Targets of miR-133b were predicted by bioinformatics tools and validated by luciferase reporter analyses, western blot, and quantitative real-time PCR. Results MiR-133b was significantly downregulated in 70% (98/140) of gastric cancer patients. Expression of miR-133b was negatively correlated with lymph node metastasis of gastric cancer in patients. Similarly, the expression of miR-133b was significantly lower in seven tested gastric cancer cell lines than in the immortalized non-cancerous GES-1 gastric epithelial cells. Overexpression of miR-133b markedly inhibited metastasis of gastric cancer cells in vitro and in vivo. Moreover, the transcriptional factor Gli1 was identified as a direct target for miR-133b. Level of Gli1 protein but not mRNA was decreased by miR-133b. Activity of luciferase with Gli1 3′-untranslated region was markedly decreased by miR-133b in gastric cancer cells. Gli1 target genes, OPN and Zeb2, were also inhibited by miR133b. Conclusions MiR-133b is frequently decreased in gastric cancer. Overexpression of miR-133b inhibits cell metastasis in vitro and in vivo partly by directly suppressing expression of Gli1 protein. These results suggested that miR-133b plays an important role in gastric cancer metastasis.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Bingya Liu
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Rui Jin Road, Shanghai 200025, People's Republic of China.
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140
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Chandramouli A, Hatsell SJ, Pinderhughes A, Koetz L, Cowin P. Gli activity is critical at multiple stages of embryonic mammary and nipple development. PLoS One 2013; 8:e79845. [PMID: 24260306 PMCID: PMC3832531 DOI: 10.1371/journal.pone.0079845] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Accepted: 09/24/2013] [Indexed: 01/12/2023] Open
Abstract
Gli3 is a transcriptional regulator of Hedgehog (Hh) signaling that functions as a repressor (Gli3R) or activator (Gli3A) depending upon cellular context. Previously, we have shown that Gli3R is required for the formation of mammary placodes #3 and #5. Here, we report that this early loss of Gli3 results in abnormal patterning of two critical regulators: Bmp4 and Tbx3, within the presumptive mammary rudiment (MR) #3 zone. We also show that Gli3 loss leads to failure to maintain mammary mesenchyme specification and loss of epithelial Wnt signaling, which impairs the later development of remaining MRs: MR#2 showed profound evagination and ectopic hairs formed within the presumptive areola; MR#4 showed mild invagination defects and males showed inappropriate retention of mammary buds in Gli3xt/xt mice. Importantly, mice genetically manipulated to misactivate Hh signaling displayed the same phenotypic spectrum demonstrating that the repressor function of Gli3R is essential during multiple stages of mammary development. In contrast, positive Hh signaling occurs during nipple development in a mesenchymal cuff around the lactiferous duct and in muscle cells of the nipple sphincter. Collectively, these data show that repression of Hh signaling by Gli3R is critical for early placodal patterning and later mammary mesenchyme specification whereas positive Hh signaling occurs during nipple development.
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Affiliation(s)
- Anupama Chandramouli
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
- The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York, United States of America
| | - Sarah J. Hatsell
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
- The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York, United States of America
| | - Alicia Pinderhughes
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
| | - Lisa Koetz
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
| | - Pamela Cowin
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
- The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York, United States of America
- * E-mail:
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141
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Mazumdar T, Sandhu R, Qadan M, DeVecchio J, Magloire V, Agyeman A, Li B, Houghton JA. Hedgehog signaling regulates telomerase reverse transcriptase in human cancer cells. PLoS One 2013; 8:e75253. [PMID: 24086482 PMCID: PMC3783395 DOI: 10.1371/journal.pone.0075253] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 08/13/2013] [Indexed: 12/31/2022] Open
Abstract
The Hedgehog (HH) signaling pathway is critical for normal embryonic development, tissue patterning and cell differentiation. Aberrant HH signaling is involved in multiple human cancers. HH signaling involves a multi-protein cascade activating the GLI proteins that transcriptionally regulate HH target genes. We have previously reported that HH signaling is essential for human colon cancer cell survival and inhibition of this signal induces DNA damage and extensive cell death. Here we report that the HH/GLI axis regulates human telomerase reverse transcriptase (hTERT), which determines the replication potential of cancer cells. Suppression of GLI1/GLI2 functions by a C-terminus truncated GLI3 repressor mutant (GLI3R), or by GANT61, a pharmacological inhibitor of GLI1/GLI2, reduced hTERT protein expression in human colon cancer, prostate cancer and Glioblastoma multiforme (GBM) cell lines. Expression of an N-terminus deleted constitutively active mutant of GLI2 (GLI2ΔN) increased hTERT mRNA and protein expression and hTERT promoter driven luciferase activity in human colon cancer cells while GANT61 inhibited hTERT mRNA expression and hTERT promoter driven luciferase activity. Chromatin immunoprecipitation with GLI1 or GLI2 antibodies precipitated fragments of the hTERT promoter in human colon cancer cells, which was reduced upon exposure to GANT61. In contrast, expression of GLI1 or GLI2ΔN in non-malignant 293T cells failed to alter the levels of hTERT mRNA and protein, or hTERT promoter driven luciferase activity. Further, expression of GLI2ΔN increased the telomerase enzyme activity, which was reduced by GANT61 administration in human colon cancer, prostate cancer, and GBM cells. These results identify hTERT as a direct target of the HH signaling pathway, and reveal a previously unknown role of the HH/GLI axis in regulating the replication potential of cancer cells. These findings are of significance in understanding the important regulatory mechanisms that determine the functions of HH/GLI signaling in cancer cells.
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Affiliation(s)
- Tapati Mazumdar
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- * E-mail:
| | - Ranjodh Sandhu
- Department of Biological, Geological and Environmental Sciences, Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, Ohio, United States of America
| | - Maha Qadan
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Jennifer DeVecchio
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Victoria Magloire
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Akwasi Agyeman
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Bibo Li
- Department of Biological, Geological and Environmental Sciences, Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, Ohio, United States of America
| | - Janet A. Houghton
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
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Abstract
PURPOSE OF REVIEW This review intends to describe recent studies on pancreatic tumor-associated stroma and potential opportunities and limitations to its targeting. RECENT FINDINGS One of the defining features of pancreatic cancer is extensive desmoplasia, or an inflammatory, fibrotic reaction. Carcinoma cells live in this complex microenvironment which is comprised of extracellular matrix (ECM), diffusible growth factors, cytokines and a variety of nonepithelial cell types including endothelial cells, immune cells, fibroblasts, myofibroblasts and stellate cells. In addition to the heterogeneity noted in the nonneoplastic cells within the tumor microenvironment, it has also been recognized that neoplastic cancer cells themselves are heterogeneous, and include a subpopulation of stem-cell like cells within tumors termed cancer stem cells. Due to the failure of current therapeutics to improve outcomes in patients with pancreatic cancer, new therapeutic avenues targeting different components of the tumor microenvironment are being investigated. In this review article, we will focus on recent studies regarding the function of the tumor stroma in pancreatic cancer and therapeutic treatments that are being advanced to target the stroma as a critical part of tumor management. SUMMARY Recent studies have shed new light on the contribution of the pancreatic cancer fibroinflammatory stroma to pancreatic cancer biology. Additional studies are needed to better define its full contribution to tumor behavior and how to best understand the optimal ways to develop therapies that counteract its pro-neoplastic properties.
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Affiliation(s)
- Meghna Waghray
- Departments of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, 48109
| | - Malica Yalamanchili
- Departments of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, 48109
| | - Marina Pasca di Magliano
- Departments of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, 48109
- Cell and Developmental Biology, University of Michigan Medical Center, Ann Arbor, Michigan, 48109
| | - Diane M. Simeone
- Departments of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, 48109
- Molecular and Integrative Physiology, University of Michigan Medical Center, Ann Arbor, Michigan, 48109
- Translational Oncology Program, University of Michigan Medical Center, Ann Arbor, Michigan, 48109
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143
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Lewis C, Krieg PA. Reagents for developmental regulation of Hedgehog signaling. Methods 2013; 66:390-7. [PMID: 23981360 DOI: 10.1016/j.ymeth.2013.08.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/10/2013] [Accepted: 08/13/2013] [Indexed: 12/11/2022] Open
Abstract
We have examined a number of reagents for their ability to modulate activity of the Hh signaling pathway during embryonic development of Xenopus. In particular we have focused on regulation of events occurring during tailbud stages and later. Two inducible protein reagents based on the Gli1 and Gli3 transcription factors were generated and the activity of these proteins was compared to the Hh signaling pathway inhibitor, cyclopamine, and the activators, Smoothened agonist (SAG) and purmorphamine (PMA). Effectiveness of reagents was assayed using both molecular biological techniques and biological readouts. We found that the small molecule modulators of the Hh pathway were highly specific and effective and produced results generally superior to the more conventional protein reagents for examination of later stage developmental processes.
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Affiliation(s)
- Cristy Lewis
- Department of Cellular and Molecular Medicine, University of Arizona College of Medicine, Tucson, AZ, United States
| | - Paul A Krieg
- Department of Cellular and Molecular Medicine, University of Arizona College of Medicine, Tucson, AZ, United States.
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144
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S-Adenosylmethionine-induced adipogenesis is accompanied by suppression of Wnt/β-catenin and Hedgehog signaling pathways. Mol Cell Biochem 2013; 382:59-73. [DOI: 10.1007/s11010-013-1718-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 05/29/2013] [Indexed: 12/21/2022]
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145
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Zhao Y, Li C, Wang M, Su L, Qu Y, Li J, Yu B, Yan M, Yu Y, Liu B, Zhu Z. Decrease of miR-202-3p expression, a novel tumor suppressor, in gastric cancer. PLoS One 2013; 8:e69756. [PMID: 23936094 PMCID: PMC3723650 DOI: 10.1371/journal.pone.0069756] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 06/11/2013] [Indexed: 01/02/2023] Open
Abstract
Emerging studies have indicated that microRNAs are involved in the development and progression of cancer. Here we found that miR-202-3p was frequently down-regulated in gastric cancer tissues. Overexpression of miR-202-3p in gastric cancer cells MKN-28 and BGC-823, markedly suppressed cell proliferation and induced cell apoptosis both in vitro and in vivo. Furthermore, Gli1 expression was frequently positive in gastric cancer tissues and inversely correlated with miR-133b expression. We demonstrate that the transcriptional factor Gli1 was a target of miR-202-3p and plays an essential role as a mediator of the biological effects of miR-202-3p in gastric cancer. MiR-202-3p also inhibited the expression of γ-catenin and BCL-2. Taken together, these findings suggest that miR-202-3p may function as a novel tumor suppressor in gastric cancer and its anti-tumor activity may attribute the direct targeting and inhibition of Gli1.
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Affiliation(s)
- Yu Zhao
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Chenglong Li
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ming Wang
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Liping Su
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ying Qu
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jianfang Li
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Beiqin Yu
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Min Yan
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yingyan Yu
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Bingya Liu
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (ZZ); (BL)
| | - Zhenggang Zhu
- Shanghai Key Laboratory of Gastric Neoplasms, Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (ZZ); (BL)
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146
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Verbeni M, Sánchez O, Mollica E, Siegl-Cachedenier I, Carleton A, Guerrero I, Ruiz i Altaba A, Soler J. Morphogenetic action through flux-limited spreading. Phys Life Rev 2013; 10:457-75. [PMID: 23831049 DOI: 10.1016/j.plrev.2013.06.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 06/17/2013] [Indexed: 10/26/2022]
Abstract
A central question in biology is how secreted morphogens act to induce different cellular responses within a group of cells in a concentration-dependent manner. Modeling morphogenetic output in multicellular systems has so far employed linear diffusion, which is the normal type of diffusion associated with Brownian processes. However, there is evidence that at least some morphogens, such as Hedgehog (Hh) molecules, may not freely diffuse. Moreover, the mathematical analysis of such models necessarily implies unrealistic instantaneous spreading of morphogen molecules, which are derived from the assumptions of Brownian motion in its continuous formulation. A strict mathematical model considering Fick's diffusion law predicts morphogen exposure of the whole tissue at the same time. Such a strict model thus does not describe true biological patterns, even if similar and attractive patterns appear as results of applying such simple model. To eliminate non-biological behaviors from diffusion models we introduce flux-limited spreading (FLS), which implies a restricted velocity for morphogen propagation and a nonlinear mechanism of transport. Using FLS and focusing on intercellular Hh-Gli signaling, we model a morphogen gradient and highlight the propagation velocity of morphogen particles as a new key biological parameter. This model is then applied to the formation and action of the Sonic Hh (Shh) gradient in the vertebrate embryonic neural tube using our experimental data on Hh spreading in heterologous systems together with published data. Unlike linear diffusion models, FLS modeling predicts concentration fronts and the evolution of gradient dynamics and responses over time. In addition to spreading restrictions by extracellular binding partners, we suggest that the constraints imposed by direct bridges of information transfer such as nanotubes or cytonemes underlie FLS. Indeed, we detect and measure morphogen particle velocity in such cell extensions in different systems.
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Affiliation(s)
- M Verbeni
- Departamento de Matemática Aplicada, Universidad de Granada, 18071-Granada, Spain
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147
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Li R, Bai Y, Liu T, Wang X, Wu Q. Induced pluripotency and direct reprogramming: a new window for treatment of neurodegenerative diseases. Protein Cell 2013; 4:415-24. [PMID: 23686735 DOI: 10.1007/s13238-013-2089-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 01/09/2013] [Indexed: 12/11/2022] Open
Abstract
Human embryonic stem cells (hESCs) are pluripotent cells that have the ability of unlimited self-renewal and can be differentiated into different cell lineages, including neural stem (NS) cells. Diverse regulatory signaling pathways of neural stem cells differentiation have been discovered, and this will be of great benefit to uncover the mechanisms of neuronal differentiation in vivo and in vitro. However, the limitations of hESCs resource along with the religious and ethical concerns impede the progress of ESCs application. Therefore, the induced pluripotent stem cells (iPSCs) via somatic cell reprogramming have opened up another new territory for regenerative medicine. iPSCs now can be derived from a number of lineages of cells, and are able to differentiate into certain cell types, including neurons. Patient-specifi c iPSCs are being used in human neurodegenerative disease modeling and drug screening. Furthermore, with the development of somatic direct reprogramming or lineage reprogramming technique, a more effective approach for regenerative medicine could become a complement for iPSCs.
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Affiliation(s)
- Rui Li
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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148
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Martynova NY, Ermolina LV, Ermakova GV, Eroshkin FM, Gyoeva FK, Baturina NS, Zaraisky AG. The cytoskeletal protein Zyxin inhibits Shh signaling during the CNS patterning in Xenopus laevis through interaction with the transcription factor Gli1. Dev Biol 2013; 380:37-48. [PMID: 23685334 DOI: 10.1016/j.ydbio.2013.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 04/24/2013] [Accepted: 05/07/2013] [Indexed: 11/19/2022]
Abstract
Zyxin is a cytoskeletal protein that controls cell movements by regulating actin filaments assembly, but it can also modulate gene expression owing to its interactions with the proteins involved in signaling cascades. Therefore, identification of proteins that interact with Zyxin in embryonic cells is a promising way to unravel mechanisms responsible for coupling of two major components of embryogenesis: morphogenetic movements and cell differentiation. Now we show that in Xenopus laevis embryos Zyxin can bind to and suppress activity of the primary effector of Sonic hedgehog (Shh) signaling cascade, the transcription factor Gli1. By using loss- and gain-of-function approaches, we demonstrate that Zyxin is essential for reduction of Shh signaling within the dorsal part of the neural tube of X. laevis embryo. Thus, our finding discloses a novel function of Zyxin in fine tuning of the central neural system patterning which is based on the ventral-to-dorsal gradient of Shh signaling.
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Affiliation(s)
- Natalia Y Martynova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
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149
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Expression of SHH signaling molecules in the developing human primary dentition. BMC DEVELOPMENTAL BIOLOGY 2013; 13:11. [PMID: 23566240 PMCID: PMC3639830 DOI: 10.1186/1471-213x-13-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 04/04/2013] [Indexed: 11/10/2022]
Abstract
Background Our current knowledge on tooth development derives primarily from studies in mice. Very little is known about gene expression and function during human odontogenesis. Sonic Hedgehog (SHH) signaling has been demonstrated to play crucial roles in the development of multiple organs in mice, including the tooth. However, if SHH signaling molecules are expressed and function in the developing human embryonic tooth remain unknown. Results We conducted microarray assay to reveal the expression profile of SHH signaling pathway molecules. We then used in situ hybridization to validate and reveal spatial and temporal expression patterns of a number of selected molecules, including SHH, PTC1, SMO, GLI1, GLI2, and GLI3, in the developing human embryonic tooth germs, and compared them with that in mice. We found that all these genes exhibit similar but slightly distinct expression patterns in the human and mouse tooth germ at the cap and bell stages. Conclusions Our results demonstrate the operation of active SHH signaling in the developing human tooth and suggest a conserved function of SHH signaling pathway during human odontogenesis.
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150
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Santini R, Vinci MC, Pandolfi S, Penachioni JY, Montagnani V, Olivito B, Gattai R, Pimpinelli N, Gerlini G, Borgognoni L, Stecca B. Hedgehog-GLI signaling drives self-renewal and tumorigenicity of human melanoma-initiating cells. Stem Cells 2013; 30:1808-18. [PMID: 22730244 DOI: 10.1002/stem.1160] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The question of whether cancer stem/tumor-initiating cells (CSC/TIC) exist in human melanomas has arisen in the last few years. Here, we have used nonadherent spheres and the aldehyde dehydrogenase (ALDH) enzymatic activity to enrich for CSC/TIC in a collection of human melanomas obtained from a broad spectrum of sites and stages. We find that melanomaspheres display extensive in vitro self-renewal ability and sustain tumor growth in vivo, generating human melanoma xenografts that recapitulate the phenotypic composition of the parental tumor. Melanomaspheres express high levels of Hedgehog (HH) pathway components and of embryonic pluripotent stem cell factors SOX2, NANOG, OCT4, and KLF4. We show that human melanomas contain a subset of cells expressing high ALDH activity (ALDH(high)), which is endowed with higher self-renewal and tumorigenic abilities than the ALDH(low) population. A good correlation between the number of ALDH(high) cells and sphere formation efficiency was observed. Notably, both pharmacological inhibition of HH signaling by the SMOOTHENED (SMO) antagonist cyclopamine and GLI antagonist GANT61 and stable expression of shRNA targeting either SMO or GLI1 result in a significant decrease in melanoma stem cell self-renewal in vitro and a reduction in the number of ALDH(high) melanoma stem cells. Finally, we show that interference with the HH-GLI pathway through lentiviral-mediated silencing of SMO and GLI1 drastically diminishes tumor initiation of ALDH(high) melanoma stem cells. In conclusion, our data indicate an essential role of the HH-GLI1 signaling in controlling self-renewal and tumor initiation of melanoma CSC/TIC. Targeting HH-GLI1 is thus predicted to reduce the melanoma stem cell compartment.
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Affiliation(s)
- Roberta Santini
- Laboratory of Tumor Cell Biology, Core Research Laboratory-Istituto Toscano Tumori, Florence, Italy
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