51
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Falkenberg KJ, Newbold A, Gould CM, Luu J, Trapani JA, Matthews GM, Simpson KJ, Johnstone RW. A genome scale RNAi screen identifies GLI1 as a novel gene regulating vorinostat sensitivity. Cell Death Differ 2016; 23:1209-18. [PMID: 26868908 DOI: 10.1038/cdd.2015.175] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 12/18/2015] [Accepted: 12/22/2015] [Indexed: 12/28/2022] Open
Abstract
Vorinostat is an FDA-approved histone deacetylase inhibitor (HDACi) that has proven clinical success in some patients; however, it remains unclear why certain patients remain unresponsive to this agent and other HDACis. Constitutive STAT (signal transducer and activator of transcription) activation, overexpression of prosurvival Bcl-2 proteins and loss of HR23B have been identified as potential biomarkers of HDACi resistance; however, none have yet been used to aid the clinical utility of HDACi. Herein, we aimed to further elucidate vorinostat-resistance mechanisms through a functional genomics screen to identify novel genes that when knocked down by RNA interference (RNAi) sensitized cells to vorinostat-induced apoptosis. A synthetic lethal functional screen using a whole-genome protein-coding RNAi library was used to identify genes that when knocked down cooperated with vorinostat to induce tumor cell apoptosis in otherwise resistant cells. Through iterative screening, we identified 10 vorinostat-resistance candidate genes that sensitized specifically to vorinostat. One of these vorinostat-resistance genes was GLI1, an oncogene not previously known to regulate the activity of HDACi. Treatment of vorinostat-resistant cells with the GLI1 small-molecule inhibitor, GANT61, phenocopied the effect of GLI1 knockdown. The mechanism by which GLI1 loss of function sensitized tumor cells to vorinostat-induced apoptosis is at least in part through interactions with vorinostat to alter gene expression in a manner that favored apoptosis. Upon GLI1 knockdown and vorinostat treatment, BCL2L1 expression was repressed and overexpression of BCL2L1 inhibited GLI1-knockdown-mediated vorinostat sensitization. Taken together, we present the identification and characterization of GLI1 as a new HDACi resistance gene, providing a strong rationale for development of GLI1 inhibitors for clinical use in combination with HDACi therapy.
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Affiliation(s)
- K J Falkenberg
- Cancer Therapeutics Program, The Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, VIC 3002, Australia
| | - A Newbold
- Cancer Therapeutics Program, The Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, VIC 3002, Australia
| | - C M Gould
- Victorian Centre for Functional Genomics, The Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, VIC 3002, Australia
| | - J Luu
- Victorian Centre for Functional Genomics, The Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, VIC 3002, Australia
| | - J A Trapani
- Cancer Immunology Program, The Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, VIC 3002, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - G M Matthews
- Cancer Therapeutics Program, The Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, VIC 3002, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - K J Simpson
- Victorian Centre for Functional Genomics, The Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, VIC 3002, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - R W Johnstone
- Cancer Therapeutics Program, The Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, VIC 3002, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC 3052, Australia
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52
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Gruber W, Hutzinger M, Elmer DP, Parigger T, Sternberg C, Cegielkowski L, Zaja M, Leban J, Michel S, Hamm S, Vitt D, Aberger F. DYRK1B as therapeutic target in Hedgehog/GLI-dependent cancer cells with Smoothened inhibitor resistance. Oncotarget 2016; 7:7134-48. [PMID: 26784250 PMCID: PMC4872774 DOI: 10.18632/oncotarget.6910] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 01/04/2016] [Indexed: 12/26/2022] Open
Abstract
A wide range of human malignancies displays aberrant activation of Hedgehog (HH)/GLI signaling, including cancers of the skin, brain, gastrointestinal tract and hematopoietic system. Targeting oncogenic HH/GLI signaling with small molecule inhibitors of the essential pathway effector Smoothened (SMO) has shown remarkable therapeutic effects in patients with advanced and metastatic basal cell carcinoma. However, acquired and de novo resistance to SMO inhibitors poses severe limitations to the use of SMO antagonists and urgently calls for the identification of novel targets and compounds.Here we report on the identification of the Dual-Specificity-Tyrosine-Phosphorylation-Regulated Kinase 1B (DYRK1B) as critical positive regulator of HH/GLI signaling downstream of SMO. Genetic and chemical inhibition of DYRK1B in human and mouse cancer cells resulted in marked repression of HH signaling and GLI1 expression, respectively. Importantly, DYRK1B inhibition profoundly impaired GLI1 expression in both SMO-inhibitor sensitive and resistant settings. We further introduce a novel small molecule DYRK1B inhibitor, DYRKi, with suitable pharmacologic properties to impair SMO-dependent and SMO-independent oncogenic GLI activity. The results support the use of DYRK1B antagonists for the treatment of HH/GLI-associated cancers where SMO inhibitors fail to demonstrate therapeutic efficacy.
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MESH Headings
- Animals
- Antineoplastic Agents/pharmacology
- Apoptosis/drug effects
- Blotting, Western
- Carcinoma, Basal Cell/drug therapy
- Carcinoma, Basal Cell/genetics
- Carcinoma, Basal Cell/metabolism
- Carcinoma, Basal Cell/pathology
- Cell Proliferation/drug effects
- Cells, Cultured
- Drug Resistance, Neoplasm
- Forkhead Transcription Factors/physiology
- Hedgehog Proteins/antagonists & inhibitors
- Hedgehog Proteins/genetics
- Hedgehog Proteins/metabolism
- Humans
- Mice
- Mice, Nude
- NIH 3T3 Cells
- Pancreatic Neoplasms/drug therapy
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/metabolism
- Pancreatic Neoplasms/pathology
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- RNA, Messenger/genetics
- RNA, Small Interfering/genetics
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Skin Neoplasms/drug therapy
- Skin Neoplasms/genetics
- Skin Neoplasms/metabolism
- Skin Neoplasms/pathology
- Smoothened Receptor/antagonists & inhibitors
- Smoothened Receptor/genetics
- Smoothened Receptor/metabolism
- Xenograft Model Antitumor Assays
- Zinc Finger Protein GLI1/antagonists & inhibitors
- Zinc Finger Protein GLI1/genetics
- Zinc Finger Protein GLI1/metabolism
- Dyrk Kinases
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Affiliation(s)
- Wolfgang Gruber
- Cancer Cluster Salzburg, Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Martin Hutzinger
- Cancer Cluster Salzburg, Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Dominik Patrick Elmer
- Cancer Cluster Salzburg, Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Thomas Parigger
- Cancer Cluster Salzburg, Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Christina Sternberg
- Cancer Cluster Salzburg, Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Lukasz Cegielkowski
- Cancer Cluster Salzburg, Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Mirko Zaja
- 4SC Discovery GmbH, Planegg-Martinsried, Germany
| | - Johann Leban
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | | | | | - Daniel Vitt
- 4SC Discovery GmbH, Planegg-Martinsried, Germany
- 4SC AG, Planegg-Martinsried, Germany
| | - Fritz Aberger
- Cancer Cluster Salzburg, Department of Molecular Biology, University of Salzburg, Salzburg, Austria
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53
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Peterson SC, Eberl M, Vagnozzi AN, Belkadi A, Veniaminova NA, Verhaegen ME, Bichakjian CK, Ward NL, Dlugosz AA, Wong SY. Basal cell carcinoma preferentially arises from stem cells within hair follicle and mechanosensory niches. Cell Stem Cell 2016; 16:400-12. [PMID: 25842978 DOI: 10.1016/j.stem.2015.02.006] [Citation(s) in RCA: 241] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 01/13/2015] [Accepted: 02/10/2015] [Indexed: 11/19/2022]
Abstract
Basal cell carcinoma (BCC) is characterized by frequent loss of PTCH1, leading to constitutive activation of the Hedgehog pathway. Although the requirement for Hedgehog in BCC is well established, the identity of disease-initiating cells and the compartments in which they reside remain controversial. By using several inducible Cre drivers to delete Ptch1 in different cell compartments in mice, we show here that multiple hair follicle stem cell populations readily develop BCC-like tumors. In contrast, stem cells within the interfollicular epidermis do not efficiently form tumors. Notably, we observed that innervated Gli1-expressing progenitors within mechanosensory touch dome epithelia are highly tumorigenic. Sensory nerves activate Hedgehog signaling in normal touch domes, while denervation attenuates touch dome-derived tumors. Together, our studies identify varying tumor susceptibilities among different stem cell populations in the skin, highlight touch dome epithelia as "hot spots" for tumor formation, and implicate cutaneous nerves as mediators of tumorigenesis.
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Affiliation(s)
- Shelby C Peterson
- Departments of Dermatology and Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Markus Eberl
- Departments of Dermatology and Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alicia N Vagnozzi
- Departments of Dermatology and Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Abdelmadjid Belkadi
- Departments of Dermatology and Neuroscience, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Natalia A Veniaminova
- Departments of Dermatology and Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Monique E Verhaegen
- Departments of Dermatology and Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Christopher K Bichakjian
- Departments of Dermatology and Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicole L Ward
- Departments of Dermatology and Neuroscience, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Andrzej A Dlugosz
- Departments of Dermatology and Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sunny Y Wong
- Departments of Dermatology and Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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54
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Active IKKβ promotes the stability of GLI1 oncogene in diffuse large B-cell lymphoma. Blood 2015; 127:605-15. [PMID: 26603838 DOI: 10.1182/blood-2015-07-658781] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/20/2015] [Indexed: 12/19/2022] Open
Abstract
GLI1 oncogene has been implicated in the pathobiology of several neoplasms including diffuse large B-cell lymphoma (DLBCL). However, mechanisms underlying GLI1-increased activity in DLBCL are poorly characterized. Herein, we demonstrate that IKKβ phosphorylates GLI1 in DLBCL. IKKβ activation increased GLI1 protein levels and transcriptional activity, whereas IKKβ silencing decreased GLI1 levels and transcriptional activity. Tumor necrosis factor-α (TNFα) mediated IKKβ activation-impaired GLI1 binding with the E3 ubiquitin ligase-ITCH, leading to decreased K48-linked ubiquitination/degradation of GLI1. We found 8 IKKβ-dependent phosphorylation sites that mediate GLI1 stability. Mutating or deleting these residues facilitated GLI1-ITCH interaction and decreased the protective effect of TNFα on GLI1 stability. IKKβ-GLI1 crosstalk is significant because combined inhibition of both molecules resulted in synergistic suppression of DLBCL viability in vivo and in vitro. By linking IKKβ-mediated nuclear factor-κB activity with GLI1, we identified a crosstalk between these 2 pathways that can inform the design of novel therapeutic strategies in DLBCL.
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55
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Targeting GLI factors to inhibit the Hedgehog pathway. Trends Pharmacol Sci 2015; 36:547-58. [DOI: 10.1016/j.tips.2015.05.006] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 12/17/2022]
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56
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Deubiquitination of Ci/Gli by Usp7/HAUSP Regulates Hedgehog Signaling. Dev Cell 2015; 34:58-72. [PMID: 26120032 DOI: 10.1016/j.devcel.2015.05.016] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 03/18/2015] [Accepted: 05/19/2015] [Indexed: 01/20/2023]
Abstract
Hedgehog (Hh) signaling plays essential roles in animal development and tissue homeostasis, and its misregulation causes congenital diseases and cancers. Regulation of the ubiquitin/proteasome-mediated proteolysis of Ci/Gli transcription factors is central to Hh signaling, but whether deubiquitinase is involved in this process remains unknown. Here, we show that Hh stimulates the binding of a ubiquitin-specific protease Usp7 to Ci, which positively regulates Hh signaling activity through inhibiting Ci ubiquitination and degradation mediated by both Slimb-Cul1 and Hib-Cul3 E3 ligases. Furthermore, we find that Usp7 forms a complex with GMP-synthetase (GMPS) to promote Hh pathway activity. Finally, we show that the mammalian counterpart of Usp7, HAUSP, positively regulates Hh signaling by modulating Gli ubiquitination and stability. Our findings reveal a conserved mechanism by which Ci/Gli is stabilized by a deubiquitination enzyme and identify Usp7/HUASP as a critical regulator of Hh signaling and potential therapeutic target for Hh-related cancers.
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57
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Loss of microRNA-27b contributes to breast cancer stem cell generation by activating ENPP1. Nat Commun 2015; 6:7318. [PMID: 26065921 PMCID: PMC4490376 DOI: 10.1038/ncomms8318] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/28/2015] [Indexed: 02/06/2023] Open
Abstract
Cancer stem cells (CSCs) have been identified in various types of cancer; however, the mechanisms by which cells acquire CSC properties such as drug resistance and tumour seeding ability are not fully understood. Here, we identified microRNA-27b (miR-27b) as a key regulator for the generation of a side-population in breast cancer cells that showed CSC properties, and also found that the anti-type II diabetes (T2D) drug metformin reduced this side-population via miR-27b-mediated repression of ectonucleotide pyrophosphatase/phosphodiesterase family member 1 (ENPP1), which is involved in T2D development. ENPP1 induced the generation of the side-population via upregulation of the ABCG2 transporter. ENPP1 was also identified as a substrate of the 26S proteasome, the activity of which is downregulated in CSCs. Overall, these results demonstrate that a T2D-associated gene plays an important role in tumour development and that its expression is strictly controlled at the mRNA and protein levels. MicroRNAs have a role in the acquisition of stem cell-like properties of cancer cells. Here the authors show that microRNA-27b mediates generation of a side-population of breast cancer stem cells, in part by regulating the protein ENPP1, which has been previously linked to the development of diabetes.
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58
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Hsia EYC, Gui Y, Zheng X. Regulation of Hedgehog signaling by ubiquitination. FRONTIERS IN BIOLOGY 2015; 10:203-220. [PMID: 26366162 PMCID: PMC4564008 DOI: 10.1007/s11515-015-1343-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Hedgehog (Hh) signaling pathway plays crucial roles both in embryonic development and in adult stem cell function. The timing, duration and location of Hh signaling activity need to be tightly controlled. Abnormalities of Hh signal transduction lead to birth defects or malignant tumors. Recent data point to ubiquitination-related posttranslational modifications of several key Hh pathway components as an important mechanism of regulation of the Hh pathway. Here we review how ubiquitination regulates the localization, stability and activity of the key Hh signaling components.
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Affiliation(s)
- Elaine Y. C. Hsia
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Yirui Gui
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Xiaoyan Zheng
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
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59
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Blonska M, Agarwal NK, Vega F. Shaping of the tumor microenvironment: Stromal cells and vessels. Semin Cancer Biol 2015; 34:3-13. [PMID: 25794825 DOI: 10.1016/j.semcancer.2015.03.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 03/04/2015] [Accepted: 03/08/2015] [Indexed: 12/12/2022]
Abstract
Lymphomas develop and progress in a specialized tissue microenvironment such as bone marrow as well as secondary lymphoid organs such as lymph node and spleen. The lymphoma microenvironment is characterized by a heterogeneous population of stromal cells, including fibroblastic reticular cells, nurse-like cells, mesenchymal stem cells, follicular dendritic cells, and inflammatory cells such as macrophages, T- and B-cells. These cell populations interact with the lymphoma cells to promote lymphoma growth, survival and drug resistance through multiple mechanisms. Angiogenesis is also recognized as an important factor associated with lymphoma progression. In recent years, we have learned that the interaction between the malignant and non-malignant cells is bidirectional and resembles, at least in part, the pattern seen between non-neoplastic lymphoid cells and the normal microenvironment of lymphoid organs. A summary of the current knowledge of lymphoma microenvironment focusing on the cellular components will be reviewed here.
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Affiliation(s)
- Marzenna Blonska
- Division of Hematology-Oncology, Department of Medicine, University of Miami and Sylvester Comprehensive Cancer Center, Miami, FL, United States
| | - Nitin K Agarwal
- Division of Hematopathology, Department of Pathology, University of Miami and Sylvester Comprehensive Cancer Center, Miami, FL, United States
| | - Francisco Vega
- Division of Hematopathology, Department of Pathology, University of Miami and Sylvester Comprehensive Cancer Center, Miami, FL, United States.
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60
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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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61
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Jia Y, Wang Y, Xie J. The Hedgehog pathway: role in cell differentiation, polarity and proliferation. Arch Toxicol 2015; 89:179-91. [PMID: 25559776 PMCID: PMC4630008 DOI: 10.1007/s00204-014-1433-1] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 12/04/2014] [Indexed: 02/07/2023]
Abstract
Hedgehog (Hh) is first described as a genetic mutation that has "spiked" phenotype in the cuticles of Drosophila in later 1970s. Since then, Hh signaling has been implicated in regulation of differentiation, proliferation, tissue polarity, stem cell population and carcinogenesis. The first link of Hh signaling to cancer was established through discovery of genetic mutations of Hh receptor gene PTCH1 being responsible for Gorlin syndrome in 1996. It was later shown that Hh signaling is associated with many types of cancer, including skin, leukemia, lung, brain and gastrointestinal cancers. Another important milestone for the Hh research field is the FDA approval for the clinical use of Hh inhibitor Erivedge/Vismodegib for treatment of locally advanced and metastatic basal cell carcinomas. However, recent clinical trials of Hh signaling inhibitors in pancreatic, colon and ovarian cancer all failed, indicating a real need for further understanding of Hh signaling in cancer. In this review, we will summarize recent progress in the Hh signaling mechanism and its role in human cancer.
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Affiliation(s)
- Yanfei Jia
- Central Laboratory, Jinan Central Hospital Affiliated to Shandong, University, Jinan, China
- Division of Hematology and Oncology, Department of Pediatrics, Wells Center for Pediatric Research, Indiana University Simon Cancer Center, Indiana University, Indianapolis, IN 46202, USA
| | - Yunshan Wang
- Central Laboratory, Jinan Central Hospital Affiliated to Shandong, University, Jinan, China
| | - Jingwu Xie
- Division of Hematology and Oncology, Department of Pediatrics, Wells Center for Pediatric Research, Indiana University Simon Cancer Center, Indiana University, Indianapolis, IN 46202, USA
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62
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Deng W, Vanderbilt DB, Lin CC, Martin KH, Brundage KM, Ruppert JM. SOX9 inhibits β-TrCP-mediated protein degradation to promote nuclear GLI1 expression and cancer stem cell properties. J Cell Sci 2015; 128:1123-38. [PMID: 25632159 DOI: 10.1242/jcs.162164] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The high mobility group box protein SOX9 and the GLI1 transcription factor play protumorigenic roles in pancreatic ductal adenocarcinoma (PDA). In Kras transgenic mice, each of these factors are crucial for the development of PDA precursor lesions. SOX9 transcription is directly regulated by GLI1, but how SOX9 functions downstream of GLI1 is unclear. We observed positive feedback, such that SOX9-deficient PDA cells have severely repressed levels of endogenous GLI1, attributed to loss of GLI1 protein stability. SOX9 associated with the F-box domain of the SKP1/CUL1/F-box (SCF) E3 ubiquitin ligase component, β-TrCP (also known as F-box/WD repeat-containing protein 1A), and suppressed its association with SKP1 and GLI1, a substrate of SCF-β-TrCP. SOX9 also tethered β-TrCP within the nucleus and promoted its degradation. SOX9 bound to β-TrCP through the SOX9 C-terminal PQA/S domain that mediates transcriptional activation. Suppression of β-TrCP in SOX9-deficient PDA cells restored GLI1 levels and promoted SOX9-dependent cancer stem cell properties. These studies identify SOX9-GLI1 positive feedback as a major determinant of GLI1 protein stability and implicate β-TrCP as a latent SOX9-bound tumor suppressor with the potential to degrade oncogenic proteins in tumor cells.
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Affiliation(s)
- Wentao Deng
- The Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506 The Mary Babb Randolph Cancer Center, West Virginia University, West Virginia 26506
| | - Daniel B Vanderbilt
- Program in Cancer Cell Biology, West Virginia University, Morgantown, West Virginia 26506
| | - Chen-Chung Lin
- The Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506 The Mary Babb Randolph Cancer Center, West Virginia University, West Virginia 26506
| | - Karen H Martin
- The Mary Babb Randolph Cancer Center, West Virginia University, West Virginia 26506
| | - Kathleen M Brundage
- The Mary Babb Randolph Cancer Center, West Virginia University, West Virginia 26506
| | - J Michael Ruppert
- The Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506 The Mary Babb Randolph Cancer Center, West Virginia University, West Virginia 26506 Program in Cancer Cell Biology, West Virginia University, Morgantown, West Virginia 26506
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63
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Amberg N, Holcmann M, Glitzner E, Novoszel P, Stulnig G, Sibilia M. Mouse models of nonmelanoma skin cancer. Methods Mol Biol 2015; 1267:217-50. [PMID: 25636471 DOI: 10.1007/978-1-4939-2297-0_10] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The skin is the largest organ of the mammalian body, made up of multiple layers, which include the epidermis, dermis, and subcutis (Alam and Ratner, N Engl J Med 344(13):975-983, 2001). The human interfollicular epidermis can be subdivided into five different layers: (1) stratum basale, (2) stratum spinosum, (3) stratum granulosum, (4) stratum lucidum, and (5) stratum corneum, all originating from basal keratinocytes by differentiation (Hameetman et al., BMC cancer 13:58, 2013; Ramirez et al., Differentiation 58(1):53-64, 1994). The epidermis is also able to generate different appendages: hair follicles (HF) and their associated sebaceous glands (Sibilia et al., Cell 102(2):211-220, 2000) as well as sweat glands (Luetteke et al., Genes Dev 8(4):399-413, 1994). The skin has important functions in several biological processes like environmental barrier, tissue regeneration, hair cycling, and wound repair. During these processes, stem cells from the interfollicular epidermis and from the hair follicle bulge are activated to renew the epidermis or hair. The epidermis and hair undergo continuous homeostatic regeneration and mutations, upon mutations which disturb the balance of homeostatic regeneration of epidermis and hair and lead to enhanced proliferation of keratinocytes, development of skin cancer is developed. Tumors that arise in the skin are mainly of three types: malignant melanoma, arising from melanocytes, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC), the latter two both arising from keratinocytes or hair follicle cells. In this chapter, we will describe some genetically engineered mouse models (GEMM) that aim at modeling human BCC and SCC and their respective precancerous lesions. We will describe the experimental approaches used in our laboratory to analyze tumor-bearing mice focusing on methods necessary for the induction of tumor growth as well as for the molecular and histological analysis of tumor tissue.
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Affiliation(s)
- Nicole Amberg
- Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center, Medical University of Vienna, Borschkegasse 8a, A-1090, Vienna, Austria
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64
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Abstract
The Hedgehog (Hh) signaling pathway governs cell growth and tissue development. Malfunctioning of several Hh pathway components, including the key transcriptional effector Gli proteins, is responsible for the onset of several tumors. Gli proteins activity is finely controlled by multilayered regulatory mechanisms, the most prominent of which is their proteasome-dependent proteolytic cleavage or massive ubiquitin-mediated proteolysis. Here, we described multiple procedures to determine whether a Gli protein is ubiquitylated both in a cellular context and in vitro, in basal conditions or by different E3 ubiquitin ligases and whether these processes are associated to Gli proteasome degradation.
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Affiliation(s)
- Paola Infante
- Center for Life NanoScience at Sapienza, Istituto Italiano di Tecnologia, 00161, Rome, Italy
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65
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Yavropoulou MP, Maladaki A, Yovos JG. The role of Notch and Hedgehog signaling pathways in pituitary development and pathogenesis of pituitary adenomas. Hormones (Athens) 2015; 14:5-18. [PMID: 25885100 DOI: 10.1007/bf03401377] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pituitary adenomas are usually benign tumors that cause symptoms by compression of surrounding structures or impaired hormone secretion. Treatment, whether surgical or medical depends, on the tumor subtype and degree of compression; however, a significant proportion of patients do not achieve optimal control of mass effects or hormonal hypersecretion. Unraveling the pathogenesis of pituitary adenomas is a critical step in the quest for new subcellular treatment targets that will decrease morbidity and mortality related to these tumors. A large diversity of pathogenetic mechanisms has been described so far including deregulation of cell cycle, molecular pathways and angiogenesis. Major signaling pathways such as Notch, Wnt and Hedgehog, which are mainly active in the early phase of pituitary organogenesis and are essential for the development of somatotrophs, lactotrophs thyrotrophs and corticotrophs, have been implicated in the pathogenesis of pituitary adenomas. In this review we present novel data regarding the role of Notch and Hedgehog regulatory networks in pituitary development and pathogenesis of pituitary adenomas.
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Affiliation(s)
- Maria P Yavropoulou
- Laboratory of Clinical and Molecular Endocrinology, 1st Department of Internal Medicine, ΑHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Anna Maladaki
- Laboratory of Clinical and Molecular Endocrinology, 1st Department of Internal Medicine, ΑHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - John G Yovos
- Laboratory of Clinical and Molecular Endocrinology, 1st Department of Internal Medicine, ΑHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
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66
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Infante P, Mori M, Alfonsi R, Ghirga F, Aiello F, Toscano S, Ingallina C, Siler M, Cucchi D, Po A, Miele E, D'Amico D, Canettieri G, De Smaele E, Ferretti E, Screpanti I, Uccello Barretta G, Botta M, Botta B, Gulino A, Di Marcotullio L. Gli1/DNA interaction is a druggable target for Hedgehog-dependent tumors. EMBO J 2014; 34:200-17. [PMID: 25476449 PMCID: PMC4298015 DOI: 10.15252/embj.201489213] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Hedgehog signaling is essential for tissue development and stemness, and its deregulation has been observed in many tumors. Aberrant activation of Hedgehog signaling is the result of genetic mutations of pathway components or other Smo-dependent or independent mechanisms, all triggering the downstream effector Gli1. For this reason, understanding the poorly elucidated mechanism of Gli1-mediated transcription allows to identify novel molecules blocking the pathway at a downstream level, representing a critical goal in tumor biology. Here, we clarify the structural requirements of the pathway effector Gli1 for binding to DNA and identify Glabrescione B as the first small molecule binding to Gli1 zinc finger and impairing Gli1 activity by interfering with its interaction with DNA. Remarkably, as a consequence of its robust inhibitory effect on Gli1 activity, Glabrescione B inhibited the growth of Hedgehog-dependent tumor cells in vitro and in vivo as well as the self-renewal ability and clonogenicity of tumor-derived stem cells. The identification of the structural requirements of Gli1/DNA interaction highlights their relevance for pharmacologic interference of Gli signaling.
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Affiliation(s)
- Paola Infante
- Center for Life NanoScience@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Mattia Mori
- Center for Life NanoScience@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Romina Alfonsi
- Department of Molecular Medicine, University La Sapienza, Rome, Italy
| | - Francesca Ghirga
- Dipartimento di Chimica e Tecnologie del Farmaco, University La Sapienza, Rome, Italy
| | - Federica Aiello
- Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa, Italy
| | - Sara Toscano
- Center for Life NanoScience@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Cinzia Ingallina
- Center for Life NanoScience@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Mariangela Siler
- Department of Molecular Medicine, University La Sapienza, Rome, Italy
| | - Danilo Cucchi
- Department of Molecular Medicine, University La Sapienza, Rome, Italy
| | - Agnese Po
- Department of Molecular Medicine, University La Sapienza, Rome, Italy
| | - Evelina Miele
- Center for Life NanoScience@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Davide D'Amico
- Department of Molecular Medicine, University La Sapienza, Rome, Italy
| | | | - Enrico De Smaele
- Department of Experimental Medicine, University La Sapienza, Rome, Italy
| | | | | | | | - Maurizio Botta
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, Philadelphia, PA, USA
| | - Bruno Botta
- Dipartimento di Chimica e Tecnologie del Farmaco, University La Sapienza, Rome, Italy
| | - Alberto Gulino
- Center for Life NanoScience@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy Department of Molecular Medicine, University La Sapienza, Rome, Italy Istituto Pasteur, Fondazione Cenci-Bolognetti - University La Sapienza, Rome, Italy IRCCS Neuromed, Pozzilli, Italy
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67
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Alteration of hedgehog signaling by chronic exposure to different pesticide formulations and unveiling the regenerative potential of recombinant sonic hedgehog in mouse model of bone marrow aplasia. Mol Cell Biochem 2014; 401:115-31. [DOI: 10.1007/s11010-014-2299-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/27/2014] [Indexed: 10/24/2022]
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68
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Lagadec C, Vlashi E, Frohnen P, Alhiyari Y, Chan M, Pajonk F. The RNA-binding protein Musashi-1 regulates proteasome subunit expression in breast cancer- and glioma-initiating cells. Stem Cells 2014; 32:135-44. [PMID: 24022895 DOI: 10.1002/stem.1537] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 03/10/2013] [Accepted: 08/17/2013] [Indexed: 01/11/2023]
Abstract
Cancer stem cells (CSCs) or tumor-initiating cells, similar to normal tissue stem cells, rely on developmental pathways, such as the Notch pathway, to maintain their stem cell state. One of the regulators of the Notch pathway is Musashi-1, a mRNA-binding protein. Musashi-1 promotes Notch signaling by binding to the mRNA of Numb, the negative regulator of Notch signaling, thus preventing its translation. CSCs have also been shown to downregulate their 26S proteasome activity in several types of solid tumors, thus making them resistant to proteasome-inhibitors used as anticancer agents in the clinic. Interestingly, the Notch pathway can be inhibited by proteasomal degradation of the Notch intracellular domain (Notch-ICD); therefore, downregulation of the 26S proteasome activity can lead to stabilization of Notch-ICD. Here, we present evidence that the downregulation of the 26S proteasome in CSCs constitutes another level of control by which Musashi-1 promotes signaling through the Notch pathway and maintenance of the stem cell phenotype of this subpopulation of cancer cells. We demonstrate that Musashi-1 mediates the downregulation of the 26S proteasome by binding to the mRNA of NF-YA, the transcriptional factor regulating 26S proteasome subunit expression, thus providing an additional route by which the degradation of Notch-ICD is prevented, and Notch signaling is sustained.
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Affiliation(s)
- Chann Lagadec
- Department of Radiation Oncology, David Geffen School of Medicine and, University of California Los Angeles, California, USA
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69
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Yucel G, Van Arnam J, Means PC, Huntzicker E, Altindag B, Lara MF, Yuan J, Kuo C, Oro AE. Partial proteasome inhibitors induce hair follicle growth by stabilizing β-catenin. Stem Cells 2014; 32:85-92. [PMID: 23963711 DOI: 10.1002/stem.1525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 07/10/2013] [Accepted: 07/24/2013] [Indexed: 01/06/2023]
Abstract
The activation of tissue stem cells from their quiescent state represents the initial step in the complex process of organ regeneration and tissue repair. While the identity and location of tissue stem cells are becoming known, how key regulators control the balance of activation and quiescence remains mysterious. The vertebrate hair is an ideal model system where hair cycling between growth and resting phases is precisely regulated by morphogen signaling pathways, but how these events are coordinated to promote orderly signaling in a spatial and temporal manner remains unclear. Here, we show that hair cycle timing depends on regulated stability of signaling substrates by the ubiquitin-proteasome system. Topical application of partial proteasomal inhibitors (PaPIs) inhibits epidermal and dermal proteasome activity throughout the hair cycle. PaPIs prevent the destruction of the key anagen signal β-catenin, resulting in more rapid hair growth and dramatically shortened telogen. We show that PaPIs induce excess β-catenin, act similarly to the GSK3β antagonist LiCl, and antagonize Dickopf-related protein-mediated inhibition of anagen. PaPIs thus represent a novel class of hair growth agents that act through transiently modifying the balance of stem cell activation and quiescence pathways.
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Affiliation(s)
- Gozde Yucel
- Program in Epithelial Biology, Stanford University, School of Medicine, Stanford, California, USA
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70
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Li YY, Tian T, Zhang R, Wang L, Xu J, Fan L, Li JY, Xu W. Association between polymorphism of GLI1 gene SNP rs2228226 and chronic lymphocytic leukemia in Chinese population. Med Oncol 2014; 31:294. [PMID: 25352360 DOI: 10.1007/s12032-014-0294-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 10/13/2014] [Indexed: 10/24/2022]
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71
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Gan GN, Eagles J, Keysar SB, Wang G, Glogowska MJ, Altunbas C, Anderson RT, Le PN, Morton JJ, Frederick B, Raben D, Wang XJ, Jimeno A. Hedgehog signaling drives radioresistance and stroma-driven tumor repopulation in head and neck squamous cancers. Cancer Res 2014; 74:7024-36. [PMID: 25297633 DOI: 10.1158/0008-5472.can-14-1346] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Local control and overall survival in patients with advanced head and neck squamous cell cancer (HNSCC) remains dismal. Signaling through the Hedgehog (Hh) pathway is associated with epithelial-to-mesenchymal transition, and activation of the Hh effector transcription factor Gli1 is a poor prognostic factor in this disease setting. Here, we report that increased GLI1 expression in the leading edge of HNSCC tumors is further increased by irradiation, where it contributes to therapeutic inhibition. Hh pathway blockade with cyclopamine suppressed GLI1 activation and enhanced tumor sensitivity to radiotherapy. Furthermore, radiotherapy-induced GLI1 expression was mediated in part by the mTOR/S6K1 pathway. Stroma exposed to radiotherapy promoted rapid tumor repopulation, and this effect was suppressed by Hh inhibition. Our results demonstrate that Gli1 that is upregulated at the tumor-stroma intersection in HNSCC is elevated by radiotherapy, where it contributes to stromal-mediated resistance, and that Hh inhibitors offer a rational strategy to reverse this process to sensitize HNSCC to radiotherapy.
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Affiliation(s)
- Gregory N Gan
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Justin Eagles
- Division of Medical Oncology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - Stephen B Keysar
- Division of Medical Oncology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - Guoliang Wang
- Division of Medical Oncology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - Magdalena J Glogowska
- Division of Medical Oncology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - Cem Altunbas
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Ryan T Anderson
- Division of Medical Oncology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - Phuong N Le
- Division of Medical Oncology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - J Jason Morton
- Division of Medical Oncology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - Barbara Frederick
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - David Raben
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Xiao-Jing Wang
- Department of Pathology, University of Colorado School of Medicine, Aurora, Colorado. Charles C. Gates Center for Stem Cell Biology, University of Colorado School of Medicine, Aurora, Colorado
| | - Antonio Jimeno
- Division of Medical Oncology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado. Charles C. Gates Center for Stem Cell Biology, University of Colorado School of Medicine, Aurora, Colorado. Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado.
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72
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Gruber W, Frischauf AM, Aberger F. An old friend with new skills: Imiquimod as novel inhibitor of Hedgehog signaling in basal cell carcinoma. Oncoscience 2014; 1:567-73. [PMID: 25594066 PMCID: PMC4278338 DOI: 10.18632/oncoscience.80] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 09/14/2014] [Indexed: 01/12/2023] Open
Abstract
Deregulated Hedgehog (HH)/GLI signaling plays an etiologic role in the initiation, progression and maintenance of many cancers. Small molecule targeting of HH signaling by inhibiting the essential pathway effector Smoothened (SMO) has proven exceptionally efficient for the treatment of advanced and metastatic basal cell carcinoma. That said, severe side effects, limited response rates, SMO-independent GLI signaling and rapid development of drug resistance limit the therapeutic success of SMO antagonists, urgently calling for the identification of alternative and additional strategies repressing oncogenic HH signaling. In this perspective article we highlight recent findings showing that the Toll-like receptor-7/8 (TLR7/8) agonist imiquimod (IMQ), an immune modulator approved for the treatment of basal cell carcinoma, can also act as a potent cell autonomous inhibitor of oncogenic HH signaling. Surprisingly, IMQ reduces HH signal strength independent of TLR signaling, via adenosine receptor (ADORA)/Adenylate cyclase (AC)/Protein kinase A (PKA) activation. We here highlight the molecular mechanisms of IMQ-mediated repression of HH/GLI and discuss the possible benefits as well as challenges of using ADORA agonists for the treatment of HH-associated cancer.
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Affiliation(s)
- Wolfgang Gruber
- Department of Molecular Biology, Division of Molecular Tumor Biology, University of Salzburg, Salzburg, Austria
| | - Anna-Maria Frischauf
- Department of Molecular Biology, Division of Molecular Tumor Biology, University of Salzburg, Salzburg, Austria
| | - Fritz Aberger
- Department of Molecular Biology, Division of Molecular Tumor Biology, University of Salzburg, Salzburg, Austria
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73
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Schmidt ML, Donninger H, Clark GJ. Ras regulates SCF(β-TrCP) protein activity and specificity via its effector protein NORE1A. J Biol Chem 2014; 289:31102-10. [PMID: 25217643 DOI: 10.1074/jbc.m114.594283] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Ras is the most frequently activated oncogene found in human cancer, but its mechanisms of action remain only partially understood. Ras activates multiple signaling pathways to promote transformation. However, Ras can also exhibit a potent ability to induce growth arrest and death. NORE1A (RASSF5) is a direct Ras effector that acts as a tumor suppressor by promoting apoptosis and cell cycle arrest. Expression of NORE1A is frequently lost in human tumors, and its mechanism of action remains unclear. Here we show that NORE1A forms a direct, Ras-regulated complex with β-TrCP, the substrate recognition component of the SCF(β-TrCP) ubiquitin ligase complex. This interaction allows Ras to stimulate the ubiquitin ligase activity of SCF(β-TrCP) toward its target β-catenin, resulting in degradation of β-catenin by the 26 S proteasome. However, the action of Ras/NORE1A/β-TrCP is substrate-specific because IκB, another substrate of SCF(β-TrCP), is not sensitive to NORE1A-promoted degradation. We identify a completely new signaling mechanism for Ras that allows for the specific regulation of SCF(β-TrCP) targets. We show that the NORE1A levels in a cell may dictate the effects of Ras on the Wnt/β-catenin pathway. Moreover, because NORE1A expression is frequently impaired in tumors, we provide an explanation for the observation that β-TrCP can act as a tumor suppressor or an oncogene in different cell systems.
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Affiliation(s)
- M Lee Schmidt
- From the Molecular Targets Group, James Graham Brown Cancer Center, Departments of Biochemistry and Molecular Biology
| | | | - Geoffrey J Clark
- Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky 40202
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74
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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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75
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Luongo C, Ambrosio R, Salzano S, Dlugosz AA, Missero C, Dentice M. The sonic hedgehog-induced type 3 deiodinase facilitates tumorigenesis of basal cell carcinoma by reducing Gli2 inactivation. Endocrinology 2014; 155:2077-88. [PMID: 24693967 PMCID: PMC5393316 DOI: 10.1210/en.2013-2108] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Thyroid hormone (TH) is an important regulator of growth, development, and metabolism. Most of the active TH T3 is generated by peripheral TH metabolism mediated by the iodothyronine deiodinases. Type 3 deiodinase (D3) inactivates T3 via specific deiodination reactions. It is an oncofetal protein frequently expressed in neoplastic tissues and is a direct target of the sonic hedgehog (Shh) pathway in basal cell carcinomas (BCCs). However, the molecular mechanisms triggered by T3 in BCC are still mostly unrevealed. Here, we demonstrate that D3 action is critical in the proliferation and survival of BCC cells. D3 depletion or T3 treatment induce apoptosis of BCC cells and attenuate Shh signaling. This is achieved through a direct impairment of Gli2 protein stability by T3. T3 induces protein kinase A, which in turn destabilizes Gli2 protein via its C-terminal degron. Finally, in a mouse model of BCC, T3-topical treatment significantly reduces tumor growth. These results demonstrate the existence of a previously unrecognized cross talk between TH and Gli2 oncogene, providing functional and mechanistic evidence of the involvement of TH metabolism in Shh-induced cancer. TH-mediated Gli2 inactivation would be beneficial for therapeutically purposes, because the inhibition of Shh-Gli2 signaling is an attractive target for several anticancer drugs, currently in clinical trials.
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Affiliation(s)
- Cristina Luongo
- Department of Clinical Medicine Surgery (C.L., M.D.), University of Naples Federico II, 80131 Naples, Italy; Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Studio di Diagnostica Nucleare (R.A.), 80142 Naples, Italy; Institute of Experimental Endocrinology and Oncology G. Salvatore-Consiglio Nazionale delle Ricerche (S.S.), 80131 Naples, Italy; Department of Dermatology and Comprehensive Cancer Center (A.A.D.), University of Michigan, Ann Arbor, Michigan 48109; and Centro di Ingegneria Genetica Biotecnologie Avanzate Scarl (C.M.), 80131 Naples, Italy
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76
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Szkandera J, Pichler M, Absenger G, Stotz M, Weissmueller M, Samonigg H, Asslaber M, Lax S, Leitner G, Winder T, Renner W, Gerger A. A functional germline variant in GLI1 implicates hedgehog signaling in clinical outcome of stage II and III colon carcinoma patients. Clin Cancer Res 2014; 20:1687-97. [PMID: 24470513 DOI: 10.1158/1078-0432.ccr-13-1517] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Cumulating evidence indicates that germline variants in the Wnt, Notch, and Hedgehog pathways are involved in colon carcinoma progression and metastasis. We investigated germline polymorphisms in a comprehensive panel of Wnt, Notch, and Hedgehog pathway genes to predict time to recurrence (TTR) and overall survival in patients with stage II and III colon carcinoma. EXPERIMENTAL DESIGN A total of 742 consecutively collected patients with stage II and III colon carcinoma were included in this retrospective study. Genomic DNA was analyzed for 18 germline polymorphisms in Wnt, Notch, and Hedgehog pathway genes (SFRP, DKK 2 and 3, AXIN2, APC, MYC, TCF7L2, NOTCH2, and GLI1) by TaqMan 5'-exonuclease assays. RESULTS In univariate analysis, the homozygous mutant variant of GLI1 rs2228226 G>C was significantly associated with decreased TTR in a recessive genetic model after adjustment for multiple testing [HR = 2.35; confidence interval (95% CI), 1.48-3.74; P < 0.001] and remained significant in multivariate analysis including clinical stage, lymphovascular-, vascular-, and perineural-invasion (HR = 2.43; CI 95%, 1.52-3.87; P < 0.001). In subanalyses, the association was limited to patients with surgery alone (HR = 3.21; CI 95%, 1.59-6.49; P = 0.001), in contrast with patients with adjuvant chemotherapy (HR = 0.82; CI 95%, 0.35-1.95; P = 0.657). When the subgroup of patients with "high-risk" GLI1 rs2228226 C/C genotype was analyzed, no benefit of adjuvant 5-fluorouracil-based chemotherapy could be found. CONCLUSION This is the first study identifying GLI1 rs2228226 G>C as an independent prognostic marker in patients with stage II and III colon carcinoma. Prospective studies are warranted to validate our findings.
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Affiliation(s)
- Joanna Szkandera
- Authors' Affiliations: Division of Clinical Oncology, Department of Medicine; Research Unit: Genetic Epidemiology and Pharmacogenetics, Division of Clinical Oncology; Institute of Pathology; Clinical Institute of Medical and Laboratory Diagnostics, Medical University of Graz; Department of Pathology, General Hospital Graz West, Graz; Department of Pathology, General Hospital of Leoben, Leoben, Austria; and Department of Medical Oncology, University Hospital Zuerich, Zuerich, Switzerland
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77
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Rishikaysh P, Dev K, Diaz D, Qureshi WMS, Filip S, Mokry J. Signaling involved in hair follicle morphogenesis and development. Int J Mol Sci 2014; 15:1647-70. [PMID: 24451143 PMCID: PMC3907891 DOI: 10.3390/ijms15011647] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/21/2013] [Accepted: 10/22/2013] [Indexed: 12/17/2022] Open
Abstract
Hair follicle morphogenesis depends on Wnt, Shh, Notch, BMP and other signaling pathways interplay between epithelial and mesenchymal cells. The Wnt pathway plays an essential role during hair follicle induction, Shh is involved in morphogenesis and late stage differentiation, Notch signaling determines stem cell fate while BMP is involved in cellular differentiation. The Wnt pathway is considered to be the master regulator during hair follicle morphogenesis. Wnt signaling proceeds through EDA/EDAR/NF-κB signaling. NF-κB regulates the Wnt pathway and acts as a signal mediator by upregulating the expression of Shh ligand. Signal crosstalk between epithelial and mesenchymal cells takes place mainly through primary cilia. Primary cilia formation is initiated with epithelial laminin-511 interaction with dermal β-1 integrin, which also upregulates expression of downstream effectors of Shh pathway in dermal lineage. PDGF signal transduction essential for crosstalk is mediated through epithelial PDGF-A and PDGFRα expressed on the primary cilia. Dermal Shh and PDGF signaling up-regulates dermal noggin expression; noggin is a potent inhibitor of BMP signaling which helps in counteracting BMP mediated β-catenin inhibition. This interplay of signaling between the epithelial and dermal lineage helps in epithelial Shh signal amplification. The dermal Wnt pathway helps in upregulation of epithelial Notch expression. Dysregulation of these pathways leads to certain abnormalities and in some cases even tumor outgrowth.
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Affiliation(s)
- Pisal Rishikaysh
- Department of Histology and Embryology, Medical Faculty in Hradec Kralove, Charles University in Prague, Simkova 870, 500 38 Hradec Kralove, Czech Republic.
| | - Kapil Dev
- Department of Histology and Embryology, Medical Faculty in Hradec Kralove, Charles University in Prague, Simkova 870, 500 38 Hradec Kralove, Czech Republic.
| | - Daniel Diaz
- Department of Histology and Embryology, Medical Faculty in Hradec Kralove, Charles University in Prague, Simkova 870, 500 38 Hradec Kralove, Czech Republic.
| | - Wasay Mohiuddin Shaikh Qureshi
- Department of Histology and Embryology, Medical Faculty in Hradec Kralove, Charles University in Prague, Simkova 870, 500 38 Hradec Kralove, Czech Republic.
| | - Stanislav Filip
- Department of Oncology and Radiotherapy, Medical Faculty in Hradec Kralove, Charles University in Prague, Simkova 870, 500 38 Hradec Kralove, Czech Republic.
| | - Jaroslav Mokry
- Department of Histology and Embryology, Medical Faculty in Hradec Kralove, Charles University in Prague, Simkova 870, 500 38 Hradec Kralove, Czech Republic.
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78
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Ciavardelli D, Bellomo M, Crescimanno C, Vella V. Type 3 deiodinase: role in cancer growth, stemness, and metabolism. Front Endocrinol (Lausanne) 2014; 5:215. [PMID: 25566187 PMCID: PMC4269192 DOI: 10.3389/fendo.2014.00215] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 11/27/2014] [Indexed: 12/17/2022] Open
Abstract
Deiodinases are selenoenzymes that catalyze thyroid hormones (THs) activation (type 1 and type 2, D1 and D2, respectively) or inactivation (type 3, D3). THs are essential for proper body development and cellular differentiation. Their intra- and extra-cellular concentrations are tightly regulated by deiodinases with a pre-receptorial control thus generating active or inactive form of THs. Changes in deiodinases expression are anatomically and temporally regulated and influence the downstream TH signaling. D3 overexpression is a feature of proliferative tissues such as embryo or cancer tissues. The enhanced TH degradation by D3 induces a local hypothyroidism, thus inhibiting THs transcriptional activity. Of note, overexpression of D3 is a feature of several highly proliferative cancers. In this paper, we review recent advances in the role of D3 in cancer growth, stemness, and metabolic phenotype. In particular, we focus on the main signaling pathways that result in the overexpression of D3 in cancer cells and are known to be relevant to cancer development, progression, and recurrence. We also discuss the potential role of D3 in cancer stem cells metabolic phenotype, an emerging topic in cancer research.
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Affiliation(s)
- Domenico Ciavardelli
- School of Human and Social Science, University “Kore” of Enna, Enna, Italy
- Center of Excellence on Aging (CeS.I.), University “G. d’Annunzio” of Chieti-Pescara, Chieti, Italy
| | - Maria Bellomo
- School of Human and Social Science, University “Kore” of Enna, Enna, Italy
| | | | - Veronica Vella
- School of Human and Social Science, University “Kore” of Enna, Enna, Italy
- Department of Clinical and Molecular Bio-Medicine, Endocrinology Unit, University of Catania, Garibaldi-Nesima Medical Center, Catania, Italy
- *Correspondence: Veronica Vella, School of Human and Social Sciences, University “Kore” of Enna, via delle Olimpiadi, Enna 94100, Italy e-mail:
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79
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Xie J, Bartels CM, Barton SW, Gu D. Targeting hedgehog signaling in cancer: research and clinical developments. Onco Targets Ther 2013; 6:1425-35. [PMID: 24143114 PMCID: PMC3797650 DOI: 10.2147/ott.s34678] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Since its first description in Drosophila by Drs Nusslein-Volhard and Wieschaus in 1980, hedgehog (Hh) signaling has been implicated in regulation of cell differentiation, proliferation, tissue polarity, stem cell maintenance, and carcinogenesis. The first link of Hh signaling to cancer was established through studies of Gorlin syndrome in 1996 by two independent teams. Later, it was shown that Hh signaling may be involved in many types of cancer, including skin, leukemia, lung, brain, and gastrointestinal cancers. In early 2012, the US Food and Drug Administration approved the clinical use of Hh inhibitor Erivedge/vismodegib for treatment of locally advanced and metastatic basal cell carcinomas. With further investigation, it is possible to see more clinical applications of Hh signaling inhibitors. In this review, we will summarize major advances in the last 3 years in our understanding of Hh signaling activation in human cancer, and recent developments in preclinical and clinical studies using Hh signaling inhibitors.
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Affiliation(s)
- Jingwu Xie
- Wells Center for Pediatric Research, Division of Hematology and Oncology, Department of Pediatrics, Indiana University Simon Cancer Center, Indiana University, Indianapolis, IN, USA
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80
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Mazzà D, Infante P, Colicchia V, Greco A, Alfonsi R, Siler M, Antonucci L, Po A, De Smaele E, Ferretti E, Capalbo C, Bellavia D, Canettieri G, Giannini G, Screpanti I, Gulino A, Di Marcotullio L. PCAF ubiquitin ligase activity inhibits Hedgehog/Gli1 signaling in p53-dependent response to genotoxic stress. Cell Death Differ 2013; 20:1688-97. [PMID: 24013724 DOI: 10.1038/cdd.2013.120] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/29/2013] [Accepted: 07/30/2013] [Indexed: 11/09/2022] Open
Abstract
The Hedgehog (Hh) signaling regulates tissue development, and its aberrant activation is a leading cause of malignancies, including medulloblastoma (Mb). Hh-dependent tumorigenesis often occurs in synergy with other mechanisms, such as loss of p53, the master regulator of the DNA damage response. To date, little is known about mechanisms connecting DNA-damaging events to morphogen-dependent processes. Here, we show that genotoxic stress triggers a cascade of signals, culminating with inhibition of the activity of Gli1, the final transcriptional effector of Hh signaling. This inhibition is dependent on the p53-mediated elevation of the acetyltransferase p300/CBP-associated factor (PCAF). Notably, we identify PCAF as a novel E3 ubiquitin ligase of Gli1. Indeed PCAF, but not a mutant with a deletion of its ubiquitination domain, represses Hh signaling in response to DNA damage by promoting Gli1 ubiquitination and its proteasome-dependent degradation. Restoring Gli1 levels rescues the growth arrest and apoptosis effect triggered by genotoxic drugs. Consistently, DNA-damaging agents fail to inhibit Gli1 activity in the absence of either p53 or PCAF. Finally, Mb samples from p53-null mice display low levels of PCAF and upregulation of Gli1 in vivo, suggesting PCAF as potential therapeutic target in Hh-dependent tumors. Together, our data define a mechanism of inactivation of a morphogenic signaling in response to genotoxic stress and unveil a p53/PCAF/Gli1 circuitry centered on PCAF that limits Gli1-enhanced mitogenic and prosurvival response.
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Affiliation(s)
- D Mazzà
- Department of Molecular Medicine, University of Rome La Sapienza, Rome, Italy
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81
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Peng Z, Ji Z, Mei F, Lu M, Ou Y, Cheng X. Lithium inhibits tumorigenic potential of PDA cells through targeting hedgehog-GLI signaling pathway. PLoS One 2013; 8:e61457. [PMID: 23626687 PMCID: PMC3634073 DOI: 10.1371/journal.pone.0061457] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Accepted: 03/09/2013] [Indexed: 12/31/2022] Open
Abstract
Hedgehog signaling pathway plays a critical role in the initiation and development of pancreatic ductal adenocarcinoma (PDA) and represents an attractive target for PDA treatment. Lithium, a clinical mood stabilizer for mental disorders, potently inhibits the activity of glycogen synthase kinase 3β (GSK3β) that promotes the ubiquitin-dependent proteasome degradation of GLI1, an important downstream component of hedgehog signaling. Herein, we report that lithium inhibits cell proliferation, blocks G1/S cell-cycle progression, induces cell apoptosis and suppresses tumorigenic potential of PDA cells through down-regulation of the expression and activity of GLI1. Moreover, lithium synergistically enhances the anti-cancer effect of gemcitabine. These findings further our knowledge of mechanisms of action for lithium and provide a potentially new therapeutic strategy for PDA through targeting GLI1.
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Affiliation(s)
- Zhonglu Peng
- State Key Laboratory of Natural Medicines and School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Zhengyu Ji
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Fang Mei
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Meiling Lu
- State Key Laboratory of Natural Medicines and School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Yu Ou
- State Key Laboratory of Natural Medicines and School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
- * E-mail: (XC); (YO)
| | - Xiaodong Cheng
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail: (XC); (YO)
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82
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Makinodan E, Marneros AG. Protein kinase A activation inhibits oncogenic Sonic hedgehog signalling and suppresses basal cell carcinoma of the skin. Exp Dermatol 2013; 21:847-52. [PMID: 23163650 DOI: 10.1111/exd.12016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Basal cell carcinoma of the skin (BCC) is caused by constitutive activation of the Sonic hedgehog (Shh) pathway, mainly through mutations either in the Shh receptor Patched (PTCH) or in its co-receptor Smoothened (Smo). Inhibitors of this pathway that are currently in clinical trials inhibit Smo. However, mutations in Smo can result in resistance to these inhibitors. To target most BCCs and avoid acquired resistance because of Smo mutations, inhibiting the Shh-pathway downstream of Smo is critical. Attractive downstream targets would be at the level of Gli proteins, the transcriptional activators of this pathway in BCCs. Previously it has been shown that Gli1 and Gli2, when phosphorylated by protein kinase A (PKA), are targeted for proteosomal degradation. Here we show that PKA activation via the cAMP agonist forskolin is sufficient to completely abolish oncogenic Smo activity in vitro. In an inducible BCC mouse model due to a Smo mutation that confers resistance to current Smo inhibitors, topical forskolin treatment significantly reduced Gli1 mRNA levels and resulted in strongly suppressed BCC tumor growth. Our data show that forskolin inhibits the growth of even those BCCs that are resistant to Smo inhibitors and provide a proof-of-principle framework for the development of topically applied human skin-permeable novel pharmacologic inhibitors of oncogenic Shh-signaling through PKA activation.
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Affiliation(s)
- Eri Makinodan
- Department of Dermatology, Harvard Medical School, Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, MA 02129, USA
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83
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Shimokawa T, Rahman MFU, Tostar U, Sonkoly E, Ståhle M, Pivarcsi A, Palaniswamy R, Zaphiropoulos PG. RNA editing of the GLI1 transcription factor modulates the output of Hedgehog signaling. RNA Biol 2013; 10:321-33. [PMID: 23324600 PMCID: PMC3594290 DOI: 10.4161/rna.23343] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The Hedgehog (HH) signaling pathway has important roles in tumorigenesis and in embryonal patterning. The Glioma-associated oncogene 1 (GLI1) is a key molecule in HH signaling, acting as a transcriptional effector and, moreover, is considered to be a potential therapeutic target for several types of cancer. To extend our previous focus on the implications of alternative splicing for HH signal transduction, we now report on an additional post-transcriptional mechanism with an impact on GLI1 activity, namely RNA editing. The GLI1 mRNA is highly edited at nucleotide 2179 by adenosine deamination in normal cerebellum, but the extent of this modification is reduced in cell lines from the cerebellar tumor medulloblastoma. Additionally, basal cell carcinoma tumor samples exhibit decreased GLI1 editing compared with normal skin. Interestingly, knocking down of either ADAR1 or ADAR2 reduces RNA editing of GLI1. This adenosine to inosine substitution leads to a change from Arginine to Glycine at position 701 that influences not only GLI1 transcriptional activity, but also GLI1-dependent cellular proliferation. Specifically, the edited GLI1, GLI1-701G, has a higher capacity to activate most of the transcriptional targets tested and is less susceptible to inhibition by the negative regulator of HH signaling suppressor of fused. However, the Dyrk1a kinase, implicated in cellular proliferation, is more effective in increasing the transcriptional activity of the non-edited GLI1. Finally, introduction of GLI1-701G into medulloblastoma cells confers a smaller increase in cellular growth relative to GLI1. In conclusion, our findings indicate that RNA editing of GLI1 is a regulatory mechanism that modulates the output of the HH signaling pathway.
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Affiliation(s)
- Takashi Shimokawa
- Department of Biosciences and Nutrition; Karolinska Institutet; Huddinge, Sweden
- Advanced Radiation Biology Research Program; Research Center for Charged Particle Therapy; National Institute of Radiological Sciences; Chiba-shi, Chiba, Japan
| | | | - Ulrica Tostar
- Department of Biosciences and Nutrition; Karolinska Institutet; Huddinge, Sweden
| | - Enikö Sonkoly
- Unit of Dermatology; Department of Medicine; Karolinska Institutet; Solna, Sweden
| | - Mona Ståhle
- Unit of Dermatology; Department of Medicine; Karolinska Institutet; Solna, Sweden
| | - Andor Pivarcsi
- Unit of Dermatology; Department of Medicine; Karolinska Institutet; Solna, Sweden
| | - Ramesh Palaniswamy
- Department of Biosciences and Nutrition; Karolinska Institutet; Huddinge, Sweden
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84
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Christensen L, Joo J, Lee S, Wai D, Triche TJ, May WA. FOXM1 is an oncogenic mediator in Ewing Sarcoma. PLoS One 2013; 8:e54556. [PMID: 23365673 PMCID: PMC3554707 DOI: 10.1371/journal.pone.0054556] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 12/14/2012] [Indexed: 02/06/2023] Open
Abstract
Ewing Family Tumors (Ewing Sarcoma and peripheral Primitive Neuroectodermal Tumor) are common bone and soft tissue malignancies of childhood, adolescence and young adulthood. Chromosomal translocation in these tumors produces fusion oncogenes of the EWS/ETS class, with EWS/FLI1 being by far the most common. EWS/ETS chimera are the only well established driver mutations in these tumors and they function as aberrant transcription factors. Understanding the downstream genes whose expression is modified has been a central approach to the study of these tumors. FOXM1 is a proliferation associated transcription factor which has increasingly been found to play a role in the pathogenesis of a wide range of human cancers. Here we demonstrate that FOXM1 is expressed in Ewing primary tumors and cell lines. Reduction in FOXM1 expression in Ewing cell lines results in diminished potential for anchorage independent growth. FOXM1 expression is enhanced by EWS/FLI1, though, unlike other tumor systems, it is not driven by expression of the EWS/FLI1 target GLI1. Thiostrepton is a compound known to inhibit FOXM1 by direct binding. We show that Thiostrepton diminishes FOXM1 expression in Ewing cell lines and this reduction reduces cell viability through an apoptotic mechanism. FOXM1 is involved in Ewing tumor pathogenesis and may prove to be a useful therapeutic target in Ewing tumors.
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MESH Headings
- Adolescent
- Animals
- Apoptosis/drug effects
- Biomarkers, Tumor/antagonists & inhibitors
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Biopsy
- Bone Neoplasms/genetics
- Bone Neoplasms/metabolism
- Bone Neoplasms/pathology
- Cell Adhesion
- Cell Line, Tumor
- Cell Survival/drug effects
- Child
- Forkhead Box Protein M1
- Forkhead Transcription Factors/antagonists & inhibitors
- Forkhead Transcription Factors/genetics
- Forkhead Transcription Factors/metabolism
- Gene Expression Regulation, Neoplastic/drug effects
- Humans
- Mice
- NIH 3T3 Cells
- Oncogene Proteins, Fusion/genetics
- Oncogene Proteins, Fusion/metabolism
- Proto-Oncogene Protein c-fli-1/genetics
- Proto-Oncogene Protein c-fli-1/metabolism
- RNA, Small Interfering/genetics
- RNA-Binding Protein EWS/genetics
- RNA-Binding Protein EWS/metabolism
- Sarcoma, Ewing/genetics
- Sarcoma, Ewing/metabolism
- Sarcoma, Ewing/pathology
- Signal Transduction/drug effects
- Thiostrepton/pharmacology
- Translocation, Genetic
- Young Adult
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Affiliation(s)
- Laura Christensen
- Division of Hematology-Oncology, Department of Pediatrics, Saban Research Institute, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Jay Joo
- Division of Hematology-Oncology, Department of Pediatrics, Saban Research Institute, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Sean Lee
- Division of Hematology-Oncology, Department of Pediatrics, Saban Research Institute, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Daniel Wai
- Department of Pathology, Saban Research Institute, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Timothy J. Triche
- Department of Pathology, Saban Research Institute, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - William A. May
- Division of Hematology-Oncology, Department of Pediatrics, Saban Research Institute, Childrens Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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85
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WIP1 phosphatase modulates the Hedgehog signaling by enhancing GLI1 function. Oncogene 2012; 32:4737-47. [PMID: 23146903 DOI: 10.1038/onc.2012.502] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 09/10/2012] [Accepted: 09/18/2012] [Indexed: 02/06/2023]
Abstract
The Hedgehog-GLI (HH-GLI) signaling plays a critical role in controlling growth and tissue patterning during embryogenesis and is implicated in a variety of human malignancies, including those of the skin. Phosphorylation events have been shown to regulate the activity of the GLI transcription factors, the final effectors of the HH-GLI signaling pathway. Here, we show that WIP1 (or PPM1D), an oncogenic phosphatase amplified/overexpressed in several types of human cancer, is a positive modulator of the HH signaling. Mechanistically, WIP1 enhances the function of GLI1 by increasing its transcriptional activity, nuclear localization and protein stability, but not of GLI2 nor GLI3. We also find that WIP1 and GLI1 are in a complex. Modulation of the transcriptional activity of GLI1 by WIP1 depends on the latter's phosphatase activity and, remarkably, does not require p53, a known WIP1 target. Functionally, we find that WIP1 is required for melanoma and breast cancer cell proliferation and self-renewal in vitro and melanoma xenograft growth induced by activation of the HH signaling. Pharmacological blockade of the HH pathway with the SMOOTHENED antagonist cyclopamine acts synergistically with inhibition of WIP1 in reducing growth of melanoma and breast cancer cells in vitro. Overall, our data uncover a role for WIP1 in modulating the activity of GLI1 and in sustaining cancer cell growth and cancer stem cell self-renewal induced by activation of the HH pathway. These findings open a novel therapeutic approach for human melanomas and, possibly, other cancer types expressing WIP1 and with activated HH pathway.
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86
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Fei DL, Sanchez-Mejias A, Wang Z, Flaveny C, Long J, Singh S, Rodriguez-Blanco J, Tokhunts R, Giambelli C, Briegel KJ, Schulz WA, Gandolfi AJ, Karagas M, Zimmers TA, Jorda M, Bejarano P, Capobianco AJ, Robbins DJ. Hedgehog signaling regulates bladder cancer growth and tumorigenicity. Cancer Res 2012; 72:4449-58. [PMID: 22815529 PMCID: PMC3809830 DOI: 10.1158/0008-5472.can-11-4123] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The role of Hedgehog (HH) signaling in bladder cancer remains controversial. The gene encoding the HH receptor and negative regulator PATCHED1 (PTCH1) resides on a region of chromosome 9q, one copy of which is frequently lost in bladder cancer. Inconsistent with PTCH1 functioning as a classic tumor suppressor gene, loss-of-function mutations in the remaining copy of PTCH1 are not commonly found. Here, we provide direct evidence for a critical role of HH signaling in bladder carcinogenesis. We show that transformed human urothelial cells and many urothelial carcinoma cell lines exhibit constitutive HH signaling, which is required for their growth and tumorigenic properties. Surprisingly, rather than originating from loss of PTCH1, the constitutive HH activity observed in urothelial carcinoma cell lines was HH ligand dependent. Consistent with this finding, increased levels of HH and the HH target gene product GLI1 were found in resected human primary bladder tumors. Furthermore, on the basis of the difference in intrinsic HH dependence of urothelial carcinoma cell lines, a gene expression signature was identified that correlated with bladder cancer progression. Our findings therefore indicate that therapeutic targeting of the HH signaling pathway may be beneficial in the clinical management of bladder cancer.
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Affiliation(s)
- Dennis Liang Fei
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
- Program in Experimental and Molecular Medicine, Department of Pharmacology and Toxicology, Dartmouth Medical School, Lebanon, NH
| | - Avencia Sanchez-Mejias
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
| | - Zhiqiang Wang
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
| | - Colin Flaveny
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
| | - Jun Long
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
| | - Samer Singh
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
| | - Jezabel Rodriguez-Blanco
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
| | - Robert Tokhunts
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
- Program in Experimental and Molecular Medicine, Department of Pharmacology and Toxicology, Dartmouth Medical School, Lebanon, NH
| | - Camilla Giambelli
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
| | - Karoline J. Briegel
- Department of Biochemistry and Molecular Biology, University of Miami, Miami, FL
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL
| | | | - A. Jay Gandolfi
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ
| | - Margaret Karagas
- Section of Biostatistics and Epidemiology, Department of Community and Family Medicine, Dartmouth Medical School, Lebanon, NH
| | - Teresa A. Zimmers
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
| | - Merce Jorda
- Department of Pathology, University of Miami, Miami, FL
| | | | - Anthony J. Capobianco
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL
| | - David J. Robbins
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami, Miami, FL
- Department of Biochemistry and Molecular Biology, University of Miami, Miami, FL
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL
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87
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A distinct Smoothened mutation causes severe cerebellar developmental defects and medulloblastoma in a novel transgenic mouse model. Mol Cell Biol 2012; 32:4104-15. [PMID: 22869526 DOI: 10.1128/mcb.00862-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Deregulated developmental processes in the cerebellum cause medulloblastoma, the most common pediatric brain malignancy. About 25 to 30% of cases are caused by mutations increasing the activity of the Sonic hedgehog (Shh) pathway, a critical mitogen in cerebellar development. The proto-oncogene Smoothened (Smo) is a key transducer of the Shh pathway. Activating mutations in Smo that lead to constitutive activity of the Shh pathway have been identified in human medulloblastoma. To understand the developmental and oncogenic effects of two closely positioned point mutations in Smo, we characterized NeuroD2-SmoA2 mice and compared them to NeuroD2-SmoA1 mice. While both SmoA1 and SmoA2 transgenes cause medulloblastoma with similar frequencies and timing, SmoA2 mice have severe aberrations in cerebellar development, whereas SmoA1 mice are largely normal during development. Intriguingly, neurologic function, as measured by specific tests, is normal in the SmoA2 mice despite extensive cerebellar dysplasia. We demonstrate how two nearly contiguous point mutations in the same domain of the encoded Smo protein can produce striking phenotypic differences in cerebellar development and organization in mice.
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88
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Woo WM, Zhen HH, Oro AE. Shh maintains dermal papilla identity and hair morphogenesis via a Noggin-Shh regulatory loop. Genes Dev 2012; 26:1235-46. [PMID: 22661232 DOI: 10.1101/gad.187401.112] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
During hair follicle morphogenesis, dermal papillae (DPs) function as mesenchymal signaling centers that cross-talk with overlying epithelium to regulate morphogenesis. While the DP regulates hair follicle formation, relatively little is known about the molecular basis of DP formation. The morphogen Sonic hedgehog (Shh) is known for regulating hair follicle epithelial growth, with excessive signaling resulting in basal cell carcinomas. Here, we investigate how dermal-specific Shh signaling contributes to DP formation and hair growth. Using a Cre-lox genetic model and RNAi in hair follicle reconstitution assays, we demonstrate that dermal Smoothened (Smo) loss of function results in the loss of the DP precursor, the dermal condensate, and a stage 2 hair follicle arrest phenotype reminiscent of Shh(-/-) skin. Surprisingly, dermal Smo does not regulate cell survival or epithelial proliferation. Rather, molecular screening and immunostaining studies reveal that dermal Shh signaling controls the expression of a subset of DP-specific signature genes. Using a hairpin/cDNA lentiviral system, we show that overexpression of the Shh-dependent gene Noggin, but not Sox2 or Sox18, can partially rescue the dermal Smo knockdown hair follicle phenotype by increasing the expression of epithelial Shh. Our findings suggest that dermal Shh signaling regulates specific DP signatures to maintain DP maturation while maintaining a reciprocal Shh-Noggin signaling loop to drive hair follicle morphogenesis.
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Affiliation(s)
- Wei-Meng Woo
- Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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89
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Gulino A, Di Marcotullio L, Canettieri G, De Smaele E, Screpanti I. Hedgehog/Gli Control by Ubiquitination/Acetylation Interplay. HEDGEHOG SIGNALING 2012; 88:211-27. [DOI: 10.1016/b978-0-12-394622-5.00009-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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90
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Abstract
Hedgehog (Hh) signaling plays a central role in many developmental processes. Hh protein is a developmental morphogen that elicits a graded cellular response depending on the distance between the recipient cell and the ligand-secreting cell. Gli transcription factors are effectors that induce the expression of downstream target genes. The outline of this cascade from Hh to Gli has been elucidated, and many components have been identified. However, the interpretation of graded ligand stimulation remains to be resolved. Among the components, adenosine 3'5'-cyclic monophosphate-dependent protein kinase (PKA) functions as a negative regulator that phosphorylates a specific region of Gli, thereby inducing proteolytic cleavage to generate the repressor form. In addition, recent studies have identified different mechanisms that are followed by PKA phosphorylation of Gli. In this review, we examine Hh signaling and PKA phosphorylation and propose a possible interaction between the multiple mechanisms regulated by PKA and the gradient-dependent response.
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Affiliation(s)
- Yoshinari Asaoka
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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91
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Carpenter RL, Lo HW. Identification, functional characterization, and pathobiological significance of GLI1 isoforms in human cancers. VITAMINS AND HORMONES 2012; 88:115-40. [PMID: 22391302 DOI: 10.1016/b978-0-12-394622-5.00006-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Glioma-associated oncogene homolog 1 (GLI1) is the nuclear mediator of Hedgehog signaling that activates gene transcription via its zinc finger DNA-binding and transactivation domains. GLI1 plays a critical role in several cellular processes, including embryonic development, tumorigenesis, and tumor growth and progression. The human GLI1 gene was identified in 1987 as an amplified gene in glioblastoma. Somatic mutations have never been reported in the GLI1 gene in any cell or tumor type. Very recently in 2008-2009, the full-length GLI1 transcript was discovered to undergo alternative splicing to form two shorter isoforms, namely N-terminal deletion variant (GLI1ΔN) and truncated GLI1 (tGLI1). Emerging evidence suggests that the three structurally different GLI1 isoforms are distinctly different in their expression patterns and functions in the context of human cancers. The tGLI1 isoform, in particular, has been shown to gain the ability to modulate expression of the genes that are not regulated by GLI1 and to support the biology of more aggressive cancer. Consequently, a key focus of this chapter is to summarize and compare the properties of the three GLI1 isoforms and their relations to malignant biology of human cancers.
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Affiliation(s)
- Richard L Carpenter
- Division of Surgical Sciences, Department of Surgery, Duke University School of Medicine, Durham, North Carolina, USA
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92
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Abstract
The Hedgehog (Hh) pathway is a conserved signalling system essential for embryonic development and for the maintenance of self-renewal pathways in progenitor cells. Mutations that deregulate Hh signalling are directly implicated in basal cell carcinoma and medulloblastoma. The mechanisms of Hh pathway activation in cancers in which no pathway mutations have been identified are less clear, but of great translational significance. Small molecule inhibitors of the pathway, many of which are in early phase clinical trials, may shed further light on this question. Canonical Hh signalling promotes the expression of target genes through the Glioma-associated oncogene (GLI) transcription factors. There is now increasing evidence suggesting that 'non-canonical' Hh signalling mechanisms, some of which are independent of GLI-mediated transcription, may be important in cancer and development. The focus of this review is to summarise some of the known mechanisms of Hh signalling as well as its emerging role in cancer.
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Affiliation(s)
- Kieren D Marini
- Monash Institute of Medical Research, Centre for Cancer Research, Monash University, Victoria, Australia
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93
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Ok CY, Singh RR, Vega F. Aberrant activation of the hedgehog signaling pathway in malignant hematological neoplasms. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:2-11. [PMID: 22056910 DOI: 10.1016/j.ajpath.2011.09.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/01/2011] [Accepted: 09/14/2011] [Indexed: 01/08/2023]
Abstract
The hedgehog (HH) signaling pathway is a highly regulated signaling pathway that is important not only for embryonic development, tissue patterning, and organogenesis but also for tissue repair and the maintenance of stem cells in adult tissues. In the adult hematopoietic system, HH signaling regulates intrathymic T-cell development, and it is one of the survival signals provided by follicular dendritic cells to prevent apoptosis in germinal center B cells. HH signaling is required for primitive hematopoiesis; however, conflicting data have been reported regarding the role of the HH pathway in adult hematopoiesis. Inappropriate activation of the HH signaling pathway occurs in several human cancers, including hematological neoplasms. Emerging data demonstrate abnormal HH pathway activation in chronic lymphocytic leukemia/small lymphocytic lymphoma, plasma cell myeloma, mantle cell lymphoma, diffuse large B-cell lymphoma, ALK-positive anaplastic large cell lymphoma, chronic myelogenous leukemia, and acute leukemias. In these neoplasms, HH signaling promotes proliferation and survival, contributes to the maintenance of cancer stem cells, and enhances tolerance or resistance to chemotherapeutic agents. Here, we review current understanding of HH signaling, its role in the pathobiology of hematological malignancies, and its potential as a therapeutic target to treat malignant hematological neoplasms.
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Affiliation(s)
- Chi Young Ok
- Department of Pathology, University of Massachusetts Medical Center, Worcester, Massachusetts, USA
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94
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Schrader EK, Harstad KG, Holmgren RA, Matouschek A. A three-part signal governs differential processing of Gli1 and Gli3 proteins by the proteasome. J Biol Chem 2011; 286:39051-8. [PMID: 21921029 DOI: 10.1074/jbc.m111.274993] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Gli proteins are the transcriptional effectors of the mammalian Hedgehog signaling pathway. In an unusual mechanism, the proteasome partially degrades or processes Gli3 in the absence of Hedgehog pathway stimulation to create a Gli3 fragment that opposes the activity of the full-length protein. In contrast, Gli1 is not processed but degraded completely, despite considerable homology with Gli3. We found that these differences in processing can be described by defining a processing signal that is composed of three parts: the zinc finger domain, an adjacent linker sequence, and a degron. Gli3 processing is inhibited when any one component of the processing signal is disrupted. We show that the zinc fingers are required for processing only as a folded structure and that the location but not the identity of the processing degron is critical. Within the linker sequence, regions of low sequence complexity play a crucial role, but other sequence features are also important. Gli1 is not processed because two components of the processing signal, the linker sequence and the degron, are ineffective. These findings provide new insights into the molecular elements that regulate Gli protein processing by the proteasome.
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Affiliation(s)
- Erin K Schrader
- Department of Molecular Biosciences and the Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Evanston, Illinois 60208, USA
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95
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In vivo RNAi screen reveals neddylation genes as novel regulators of Hedgehog signaling. PLoS One 2011; 6:e24168. [PMID: 21931660 PMCID: PMC3169580 DOI: 10.1371/journal.pone.0024168] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 08/01/2011] [Indexed: 11/19/2022] Open
Abstract
Hedgehog (Hh) signaling is highly conserved in all metazoan animals and plays critical roles in many developmental processes. Dysregulation of the Hh signaling cascade has been implicated in many diseases, including cancer. Although key components of the Hh pathway have been identified, significant gaps remain in our understanding of the regulation of individual Hh signaling molecules. Here, we report the identification of novel regulators of the Hh pathway, obtained from an in vivo RNA interference (RNAi) screen in Drosophila. By selectively targeting critical genes functioning in post-translational modification systems utilizing ubiquitin (Ub) and Ub-like proteins, we identify two novel genes (dUba3 and dUbc12) that negatively regulate Hh signaling activity. We provide in vivo and in vitro evidence illustrating that dUba3 and dUbc12 are essential components of the neddylation pathway; they function in an enzyme cascade to conjugate the ubiquitin-like NEDD8 modifier to Cullin proteins. Neddylation activates the Cullin-containing ubiquitin ligase complex, which in turn promotes the degradation of Cubitus interruptus (Ci), the downstream transcription factor of the Hh pathway. Our study reveals a conserved molecular mechanism of the neddylation pathway in Drosophila and sheds light on the complex post-translational regulations in Hh signaling.
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96
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Marks SA, Kalderon D. Regulation of mammalian Gli proteins by Costal 2 and PKA in Drosophila reveals Hedgehog pathway conservation. Development 2011; 138:2533-42. [PMID: 21610030 DOI: 10.1242/dev.063479] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hedgehog (Hh) signaling activates full-length Ci/Gli family transcription factors and prevents Ci/Gli proteolytic processing to repressor forms. In the absence of Hh, Ci/Gli processing is initiated by direct Pka phosphorylation. Despite those fundamental similarities between Drosophila and mammalian Hh pathways, the differential reliance on cilia and some key signal transduction components had suggested a major divergence in the mechanisms that regulate Ci/Gli protein activities, including the role of the kinesin-family protein Costal 2 (Cos2), which directs Ci processing in Drosophila. Here, we show that Cos2 binds to three regions of Gli1, just as for Ci, and that Cos2 functions to silence mammalian Gli1 in Drosophila in a Hh-regulated manner. Cos2 and the mammalian kinesin Kif7 can also direct Gli3 and Ci processing in fly, underscoring a fundamental conserved role for Cos2 family proteins in Hh signaling. We also show that direct PKA phosphorylation regulates the activity, rather than the proteolysis of Gli in Drosophilia, and we provide evidence for an analogous action of PKA on Ci.
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Affiliation(s)
- Steven A Marks
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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97
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Jin Z, Mei W, Strack S, Jia J, Yang J. The antagonistic action of B56-containing protein phosphatase 2As and casein kinase 2 controls the phosphorylation and Gli turnover function of Daz interacting protein 1. J Biol Chem 2011; 286:36171-9. [PMID: 21878643 DOI: 10.1074/jbc.m111.274761] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Hedgehog (Hh) pathway is evolutionarily conserved and plays critical roles during embryonic development and adult tissue homeostasis. Defective Hh signaling has been linked to a wide range of birth defects and cancers. Hh family proteins regulate the expression of their downstream target genes through the control of proteolytic processing and the transcriptional activation function of Gli transcription factors. Although Hh-dependent regulation of Gli has been studied extensively, other Gli regulatory mechanisms remain relatively unappreciated. Here we report our identification of a novel signaling cascade that controls the stability of Gli proteins. This cascade consists of Daz interacting protein 1 (Dzip1), casein kinase 2 (CK2), and B56 containing protein phosphatase 2As (PP2As). We provide evidence that Dzip1 is involved in a novel Gli turnover pathway. We show that CK2 directly phosphorylates Dzip1 at four serine residues, Ser-664/665/706/714. B56-containing PP2As, through binding to a domain located between amino acid residue 474 and 550 of Dzip1, dephosphorylate Dzip1 on these CK2 sites. Our mutagenesis analysis further demonstrates that the unphosphorylatable form of Dzip1 is more potent in promoting Gli turnover. Consistently, we found that the stability of Gli proteins was decreased upon CK2 inhibition and increased by inhibition of B56-containing PP2As. Thus, reversible phosphorylation of Dzip1, which is controlled by the antagonistic action of CK2 and B56-containing PP2As, has an important impact on the stability of Gli transcription factors and Hh signaling.
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Affiliation(s)
- Zhigang Jin
- The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, the Ohio State University, Columbus, Ohio 43205, USA
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98
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Abstract
Gli zinc-finger proteins are transcription factors involved in the intracellular signal transduction controlled by the Hedgehog family of secreted molecules. They are frequently mutated in human congenital malformations, and their abnormal regulation leads to tumorigenesis. Genetic studies in several model systems indicate that their activity is tightly regulated by Hedgehog signaling through various posttranslational modifications, including phosphorylation, ubiquitin-mediated degradation, and proteolytic processing, as well as through nucleocytoplasmic shuttling. In vertebrate cells, primary cilia are required for the sensing of Hedgehog pathway activity and involved in the processing and activation of Gli proteins. Two evolutionarily conserved Hedgehog pathway components, Suppressor of fused and Kif7, are core intracellular regulators of mammalian Gli proteins. Recent studies revealed that Gli proteins are also regulated transcriptionally and posttranslationally through noncanonical mechanisms independent of Hedgehog signaling. In this review, we describe the regulation of Gli proteins during development and discuss possible mechanisms for their abnormal activation during tumorigenesis.
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Affiliation(s)
- Chi-Chung Hui
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada.
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99
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Zhu H, Lo HW. The Human Glioma-Associated Oncogene Homolog 1 (GLI1) Family of Transcription Factors in Gene Regulation and Diseases. Curr Genomics 2011; 11:238-45. [PMID: 21119888 PMCID: PMC2930663 DOI: 10.2174/138920210791233108] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 04/07/2010] [Accepted: 04/07/2010] [Indexed: 12/30/2022] Open
Abstract
Sonic hedgehog (Shh) signaling is critically important for embryogenesis and other cellular processes in which GLI transcription factors mediate the terminal effects of the pathway. GLI1, in particular, plays a significant role in human cancers. Consequently, GLI1 and its upstream positive regulator Smoothened (SMO) are important targets of anti-cancer therapy and several SMO-targeted small molecule inhibitors are being evaluated clinically. Emerging exciting evidence reveals a high level of complexity that lies within the GLI1-mediated pathway. For example, a recent study provided evidence linking the polymorphic GLI1 variants Q1100/E1100 to chronic inflammatory bowel diseases. Two recent reports uncovered the existence of two novel human GLI1 isoforms that differ structurally and functionally from the wild-type GLI1 identified over two decades ago. Interestingly, although both are products of alternative splicing, GLI1∆N and tGLI1 (truncated GLI1) isoforms are predominantly expressed in normal and malignant tissues, respectively. In addition to these important discoveries, gene expression profiling studies have identified a number of novel wild-type GLI1 and tGLI1 target genes, linking wild-type GLI1 to tumor progression and therapeutic resistance, and tGLI1 to tumor invasion and migration. In light of these new insights, this review will provide a comprehensive overview on GLI1 polymorphisms and the three members of the GLI1 family of proteins, and their impacts on human diseases, including, cancers.
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Affiliation(s)
- Hu Zhu
- Department of Surgery, Division of Surgical Sciences, Duke University School of Medicine
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100
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Grachtchouk M, Pero J, Yang SH, Ermilov AN, Michael LE, Wang A, Wilbert D, Patel RM, Ferris J, Diener J, Allen M, Lim S, Syu LJ, Verhaegen M, Dlugosz AA. Basal cell carcinomas in mice arise from hair follicle stem cells and multiple epithelial progenitor populations. J Clin Invest 2011; 121:1768-81. [PMID: 21519145 DOI: 10.1172/jci46307] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 03/02/2011] [Indexed: 12/17/2022] Open
Abstract
Uncontrolled Hedgehog (Hh) signaling leads to the development of basal cell carcinoma (BCC), the most common human cancer, but the cell of origin for BCC is unclear. While Hh pathway dysregulation is common to essentially all BCCs, there exist multiple histological subtypes, including superficial and nodular variants, raising the possibility that morphologically distinct BCCs may arise from different cellular compartments in skin. Here we have shown that induction of a major mediator of Hh signaling, GLI2 activator (GLI2ΔN), selectively in stem cells of resting hair follicles in mice, induced nodular BCC development from a small subset of cells in the lower bulge and secondary hair germ compartments. Tumorigenesis was markedly accelerated when GLI2ΔN was induced in growing hair follicles. In contrast, induction of GLI2ΔN in epidermis led to the formation of superficial BCCs. Expression of GLI2ΔN at reduced levels in mice yielded lesions resembling basaloid follicular hamartomas, which have previously been linked to low-level Hh signaling in both mice and humans. Our data show that the cell of origin, tissue context (quiescent versus growing hair follicles), and level of oncogenic signaling can determine the phenotype of Hh/Gli-driven skin tumors, with high-level signaling required for development of superficial BCC-like tumors from interfollicular epidermis and nodular BCC-like tumors from hair follicle stem cells.
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Affiliation(s)
- Marina Grachtchouk
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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