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Bogush D, Schramm J, Ding Y, He B, Singh C, Sharma A, Tukaramrao DB, Iyer S, Desai D, Nalesnik G, Hengst J, Bhalodia R, Gowda C, Dovat S. Signaling pathways and regulation of gene expression in hematopoietic cells. Adv Biol Regul 2023; 88:100942. [PMID: 36621151 DOI: 10.1016/j.jbior.2022.100942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/06/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Cellular functions are regulated by signal transduction pathway networks consisting of protein-modifying enzymes that control the activity of many downstream proteins. Protein kinases and phosphatases regulate gene expression by reversible phosphorylation of transcriptional factors, which are their direct substrates. Casein kinase II (CK2) is a serine/threonine kinase that phosphorylates a large number of proteins that have critical roles in cellular proliferation, metabolism and survival. Altered function of CK2 has been associated with malignant transformation, immunological disorders and other types of diseases. Protein phosphatase 1 (PP1) is a serine/threonine phosphatase, which regulates the phosphorylation status of many proteins that are essential for cellular functions. IKAROS is a DNA-binding protein, which functions as a regulator of gene transcription in hematopoietic cells. CK2 directly phosphorylates IKAROS at multiple phosphosites which determines IKAROS activity as a regulator of gene expression. PP1 binds to IKAROS via the PP1-consensus recognition site and dephosphorylates serine/threonine residues that are phosphorylated by CK2. Thus, the interplay between CK2 and PP1 signaling pathways have opposing effects on the phosphorylation status of their mutual substrate - IKAROS. This review summarizes the effects of CK2 and PP1 on IKAROS role in regulation of gene expression and its function as a tumor suppressor in leukemia.
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Affiliation(s)
- Daniel Bogush
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Joseph Schramm
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Yali Ding
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Bing He
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Chingakham Singh
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Arati Sharma
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | | | - Soumya Iyer
- University of Chicago, Chicago, IL, 60637, USA
| | - Dhimant Desai
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Gregory Nalesnik
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Jeremy Hengst
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Riya Bhalodia
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Chandrika Gowda
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA.
| | - Sinisa Dovat
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA.
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Human growth hormone proteoform pattern changes in pituitary adenomas: Potential biomarkers for 3P medical approaches. EPMA J 2021; 12:67-89. [PMID: 33786091 DOI: 10.1007/s13167-021-00232-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 01/11/2021] [Indexed: 12/19/2022]
Abstract
Relevance Human growth hormone (hGH) is synthesized, stored, and secreted by somatotroph cells in the pituitary gland, and promotes human growth and metabolism. Compared to a normal pituitary, a GH-secreting pituitary adenoma can secrete excessive GH to cause pathological changes in body tissues. GH proteoform changes would be associated with GH-related disease pathogenesis. Purpose This study aimed to elucidate changes in GH proteoforms between GH-secreting pituitary adenomas and control pituitaries for the predictive diagnostics, targeted prevention, and personalization of medical services. Methods The isoelectric point (pI) and relative molecular mass (Mr) are two basic features of a proteoform that can be used to effectively array and detect proteoforms with two-dimensional gel electrophoresis (2DGE) and 2DGE-based western blot. GH proteoforms were characterized with liquid chromatography (LC) and mass spectrometry (MS). Phosphoproteomics, ubiquitinomics, acetylomics, and bioinformatics were used to analyze post-translational modifications (PTMs) of GH proteoforms in GH-secreting pituitary adenoma tissues and control pituitaries. Results Sixty-six 2D gel spots were found to contain hGH, including 46 spots (46 GH proteoforms) in GH-secreting pituitary adenomas and 35 spots (35 GH proteoforms) in control pituitaries. Further, 35 GH proteoforms in control pituitary tissues were matched with 35 of 46 GH proteoforms in GH-secreting pituitary adenoma tissues; and 11 GH proteoforms were presented in only GH-secreting pituitary adenoma tissues but not in control pituitary tissues. The matched 35 GH proteoforms showed quantitative changes in GH-secreting pituitary adenomas compared to the controls. The quantitative levels of those 46 GH proteoforms in GH-secreting pituitary adenomas were significantly different from those 35 GH proteoforms in control pituitaries. Meanwhile, different types of PTMs were identified among those GH proteoforms. Phosphoproteomics identified phosphorylation at residues Ser77, Ser132, Ser134, Thr174, and Ser176 in hGH. Ubiquitinomics identified ubiquitination at residue Lys96 in hGH. Acetylomics identified acetylation at reside Lys171 in hGH. Deamination was identified at residue Asn178 in hGH. Conclusion These findings provide the first hGH proteoform pattern changes in GH-secreting pituitary adenoma tissues compared to control pituitary tissues, and the status of partial PTMs in hGH proteoforms. Those data provide in-depth insights into biological roles of hGH in GH-related diseases, and identify hGH proteoform pattern biomarkers for treatment of a GH-secreting pituitary adenoma in the context of 3P medicine -predictive diagnostics, targeted prevention, and personalization of medical services. Supplementary information The online version contains supplementary material available at 10.1007/s13167-021-00232-7.
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Asa SL, Mete O, Ezzat S. Genomics and Epigenomics of Pituitary Tumors: What Do Pathologists Need to Know? Endocr Pathol 2021; 32:3-16. [PMID: 33433883 DOI: 10.1007/s12022-021-09663-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 12/11/2022]
Abstract
Molecular pathology has advanced our understanding of many tumors and offers opportunities to identify novel therapies. In the pituitary, the field has uncovered several genetic mutations that predispose to pituitary neuroendocrine tumor (PitNET) development, including MEN1, CDKN1B, PRKRIα, AIP, GPR101, and other more rare events; however, these genes are only rarely mutated in sporadic PitNETs. Recurrent genetic events in sporadic PitNETs include GNAS mutations in a subset of somatotroph tumors and ubiquitin-specific peptidase mutations (e.g., USP8, USP48) in some corticotroph tumors; to date, neither of these has resulted in altered management, and instead, the prognosis and management of PitNETs still rely more on cell type and subtype as well as local growth that determines surgical resectability. In contrast, craniopharyngiomas have either CTNNB1 or BRAFV600E mutations that correlate with adamantinomatous or papillary morphology, respectively; the latter offers the opportunity for targeted therapy. DICER1 mutations are found in patients with pituitary blastoma. Epigenetic changes are implicated in the pathogenesis of the more common sporadic pituitary neoplasms including the majority of PitNETs and tumors of pituicytes.
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Affiliation(s)
- Sylvia L Asa
- Department of Pathology, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, USA.
- Department of Pathology, University Health Network, Toronto, ON, Canada.
| | - Ozgur Mete
- Department of Pathology, University Health Network, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Shereen Ezzat
- Department of Medicine, University Health Network and University of Toronto, Toronto, ON, Canada
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Wen S, Li J, Yang J, Li B, Li N, Zhan X. Quantitative Acetylomics Revealed Acetylation-Mediated Molecular Pathway Network Changes in Human Nonfunctional Pituitary Neuroendocrine Tumors. Front Endocrinol (Lausanne) 2021; 12:753606. [PMID: 34712204 PMCID: PMC8546192 DOI: 10.3389/fendo.2021.753606] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/27/2021] [Indexed: 12/11/2022] Open
Abstract
Acetylation at lysine residue in a protein mediates multiple cellular biological processes, including tumorigenesis. This study aimed to investigate the acetylated protein profile alterations and acetylation-mediated molecular pathway changes in human nonfunctional pituitary neuroendocrine tumors (NF-PitNETs). The anti-acetyl antibody-based label-free quantitative proteomics was used to analyze the acetylomes between NF-PitNETs (n = 4) and control pituitaries (n = 4). A total of 296 acetylated proteins with 517 acetylation sites was identified, and the majority of which were significantly down-acetylated in NF-PitNETs (p<0.05 or only be quantified in NF-PitNETs/controls). These acetylated proteins widely functioned in cellular biological processes and signaling pathways, including metabolism, translation, cell adhesion, and oxidative stress. The randomly selected acetylated phosphoglycerate kinase 1 (PGK1), which is involved in glycolysis and amino acid biosynthesis, was further confirmed with immunoprecipitation and western blot in NF-PitNETs and control pituitaries. Among these acetylated proteins, 15 lysine residues within 14 proteins were down-acetylated and simultaneously up-ubiquitinated in NF-PitNETs to demonstrate a direct competition relationship between acetylation and ubiquitination. Moreover, the potential effect of protein acetylation alterations on NF-PitNETs invasiveness was investigated. Overlapping analysis between acetylomics data in NF-PitNETs and transcriptomics data in invasive NF-PitNETs identified 26 overlapped molecules. These overlapped molecules were mainly involved in metabolism-associated pathways, which means that acetylation-mediated metabolic reprogramming might be the molecular mechanism to affect NF-PitNET invasiveness. This study provided the first acetylomic profiling and acetylation-mediated molecular pathways in human NF-PitNETs, and offered new clues to elucidate the biological functions of protein acetylation in NF-PitNETs and discover novel biomarkers for early diagnosis and targeted therapy of NF-PitNETs.
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Affiliation(s)
- Siqi Wen
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Central South University, Changsha, China
- Medical Science and Technology Innovation Center, Shandong First Medical University, Jinan, China
| | - Jiajia Li
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Central South University, Changsha, China
- Medical Science and Technology Innovation Center, Shandong First Medical University, Jinan, China
| | - Jingru Yang
- Medical Science and Technology Innovation Center, Shandong First Medical University, Jinan, China
| | - Biao Li
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Central South University, Changsha, China
- Medical Science and Technology Innovation Center, Shandong First Medical University, Jinan, China
| | - Na Li
- Medical Science and Technology Innovation Center, Shandong First Medical University, Jinan, China
- Shandong Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University, Jinan, China
| | - Xianquan Zhan
- Medical Science and Technology Innovation Center, Shandong First Medical University, Jinan, China
- Shandong Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University, Jinan, China
- Gastroenterology Research Institute and Clinical Center, Shandong First Medical University, Jinan, China
- *Correspondence: Xianquan Zhan,
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Zhao W, Chen TB, Wang H. Ikaros is heterogeneously expressed in lung adenocarcinoma and is involved in its progression. J Int Med Res 2020; 48:300060520945860. [PMID: 32787735 DOI: 10.1177/0300060520945860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE The aim of the present study was to assess the expression of the Ikaros transcription factor (IKZF1) in lung adenocarcinoma and investigate whether expression levels of Ikaros are correlated with lung adenocarcinoma progression. METHODS We conducted a retrospective study of 325 cases of resected stage I pulmonary adenocarcinoma, in which histological subtyping was performed according to the 2015 World Health Organization classification. We performed immunohistochemical examinations to assess expression of Ikaros in pulmonary adenocarcinomas and evaluated the correlation between Ikaros expression and cancer progression. RESULTS Immunohistochemical staining was heterogeneous, with the majority of well-differentiated and moderately differentiated lung adenocarcinomas being weakly positive and the majority of the poorly differentiated lung adenocarcinomas exhibiting strong positive staining. Higher expression of Ikaros was associated with tumor recurrence or metastasis. CONCLUSIONS Ikaros is heterogeneously expressed in different subtypes of lung adenocarcinoma; higher expression of Ikaros was found to be associated with cancer progression.
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Affiliation(s)
- Wei Zhao
- The First People's Hospital of Changzhou, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Tong-Bing Chen
- The First People's Hospital of Changzhou, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Hui Wang
- The First People's Hospital of Changzhou, The Third Affiliated Hospital of Soochow University, Changzhou, China
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Rahmani M, Fardi M, Farshdousti Hagh M, Hosseinpour Feizi AA, Talebi M, Solali S. An investigation of methylation pattern changes in the IKZF1 promoter in patients with childhood B-cell acute lymphoblastic leukemia. Blood Res 2019; 54:144-148. [PMID: 31309094 PMCID: PMC6614096 DOI: 10.5045/br.2019.54.2.144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/09/2019] [Accepted: 04/04/2019] [Indexed: 11/29/2022] Open
Abstract
Background Ikaros family zinc finger 1 (IKZF1) is a transcription factor with an important role in controlling hematopoietic proliferation and function, particularly lymphoid cell differentiation. It was previously shown that various mechanisms and expression patterns of Ikaros are linked to a variety of cancers. We hypothesized that aberrant methylation (hypomethylation) of the IKZF1 promoter region might be one of the causes of B-cell acute lymphoblastic leukemia (B-ALL). In B-ALL patients, an increased expression of this gene is a potential cause of B-cell differentiation arrest and proliferation induction. Therefore, as more than 90% of patients with ALL are <15 years old, we investigated the methylation pattern of the IKZF1 promoter in childhood B-ALL. Methods Twenty-five newly diagnosed B-ALL cases were included (all younger than 15 yr). In addition, we selected 25 healthy age- and sex-matched children as the control group. We collected the blood samples in EDTA-containing tubes and isolated lymphocytes from whole blood using Ficoll 1.077 Lymphosep. Next, we extracted genomic DNA with the phenol/chloroform method. Two microgram of DNA per sample was treated with sodium bisulfite using the EpiTect Bisulfite Kit, followed by an assessment of DNA methylation by polymerase chain reaction (PCR) analysis of the bisulfite-modified genomic DNA. Results Our data highlighted a hypomethylated status of the IKZF1 promoter in the ALL cases (96% of the cases were unmethylated). In contrast, the control group samples were partially methylated (68%). Conclusion This study demonstrated a hypomethylated pattern of the IKZF1 promoter region in childhood B-ALL, which might underlie the aberrant Ikaros expression patterns that were previously linked to this malignancy.
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Affiliation(s)
- Mina Rahmani
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Masoumeh Fardi
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | | | - Mehdi Talebi
- Immunology Department, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Saeed Solali
- Molecular Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Immunology, Division of Hematology and Transfusion Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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Ezzat S, Cheng S, Asa SL. Epigenetics of pituitary tumors: Pathogenetic and therapeutic implications. Mol Cell Endocrinol 2018; 469:70-76. [PMID: 28711607 DOI: 10.1016/j.mce.2017.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/21/2017] [Accepted: 07/11/2017] [Indexed: 11/25/2022]
Abstract
Genetic mutations involving oncogenes or tumor suppressor genes are relatively uncommon in human sporadic pituitary tumors. Instead, increasing evidence has highlighted frequent epigenetic alterations including DNA methylation, histone modifications, and enhanced miRNA expression. This review covers some of this evidence as it illuminates mechanisms of tumorigenesis and highlights therapeutic opportunities.
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Affiliation(s)
- Shereen Ezzat
- Department of Medicine, University of Toronto, The Endocrine Oncology Site Group, Princess Margaret Cancer Centre, and The Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada.
| | - Sonia Cheng
- Department of Medicine, University of Toronto, The Endocrine Oncology Site Group, Princess Margaret Cancer Centre, and The Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada
| | - Sylvia L Asa
- Department of Laboratory Medicine & Pathobiology, University of Toronto, The Endocrine Oncology Site Group, Princess Margaret Cancer Centre, and The Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada
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Shen Z, Asa SL, Ezzat S. The retrotransposon gag domain containing protein Rgag4 is an Ikaros target in the pituitary. Mol Cell Endocrinol 2018; 461:188-193. [PMID: 28919299 DOI: 10.1016/j.mce.2017.09.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 08/28/2017] [Accepted: 09/13/2017] [Indexed: 11/18/2022]
Abstract
Previous studies have established the common and critical involvement of the zinc finger protein Ikaros in lymphoid and pituitary cell development and expansion. Key to the assembly of several transcriptional networks, we have demonstrated up-regulation of Ikaros and its interacting partner the C-terminal Binding Protein (CtBP) in response to hypoxia. This prompted us to explore common transcriptional targets using a chromatin immunoprecipitate (ChIP) screen of DNA from pituitary corticotroph cells. This strategy yielded a finite list of targets common to both transcription factors that included the metalloprotease ADAMTS10. In this report, we focus on validation of a second candidate target, the retrotransposon gag domain containing protein Rgag4. We identified the ability of Ikaros to bind the Rgag4 promoter, influence its transcriptional activity, and induce endogenous gene expression. Robust expression of Rgag4 was noted in the anterior lobe of the pituitary gland which was diminished in Ikaros knockout mice. Down-regulation of Rgag4 resulted in profound reduction of hormone gene expression with diminished ACTH secretion, recapitulating the effect of Ikaros deficiency in knockout mice. The results introduce Rgag4 to the repertoire of effectors serving to couple the chromatin remodeler Ikaros with the hormonal stress response.
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Affiliation(s)
- Zhongyi Shen
- Departments of Medicine, Toronto, Ontario, M5G 2M9, Canada; University of Toronto, University Health Network and the Ontario Cancer Institute, Toronto, Ontario, M5G 2M9, Canada
| | - Sylvia L Asa
- Laboratory Medicine & Pathobiology, Toronto, Ontario, M5G 2M9, Canada; University of Toronto, University Health Network and the Ontario Cancer Institute, Toronto, Ontario, M5G 2M9, Canada
| | - Shereen Ezzat
- Departments of Medicine, Toronto, Ontario, M5G 2M9, Canada; University of Toronto, University Health Network and the Ontario Cancer Institute, Toronto, Ontario, M5G 2M9, Canada.
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Spoletini M, Taurone S, Tombolini M, Minni A, Altissimi G, Wierzbicki V, Giangaspero F, Parnigotto PP, Artico M, Bardella L, Agostinelli E, Pastore FS. Trophic and neurotrophic factors in human pituitary adenomas (Review). Int J Oncol 2017; 51:1014-1024. [PMID: 28902350 DOI: 10.3892/ijo.2017.4120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/17/2017] [Indexed: 11/06/2022] Open
Abstract
The pituitary gland is an organ that functionally connects the hypothalamus with the peripheral organs. The pituitary gland is an important regulator of body homeostasis during development, stress, and other processes. Pituitary adenomas are a group of tumors arising from the pituitary gland: they may be subdivided in functional or non-functional, depending on their hormonal activity. Some trophic and neurotrophic factors seem to play a key role in the development and maintenance of the pituitary function and in the regulation of hypothalamo-pituitary-adrenocortical axis activity. Several lines of evidence suggest that trophic and neurotrophic factors may be involved in pituitary function, thus suggesting a possible role of the trophic and neurotrophic factors in the normal development of pituitary gland and in the progression of pituitary adenomas. Additional studies might be necessary to better explain the biological role of these molecules in the development and progression of this type of tumor. In this review, in light of the available literature, data on the following neurotrophic factors are discussed: ciliary neurotrophic factor (CNTF), transforming growth factors β (TGF‑β), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF), vascular endothelial growth inhibitor (VEGI), fibroblast growth factors (FGFs) and epidermal growth factor (EGF) which influence the proliferation and growth of pituitary adenomas.
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Affiliation(s)
- Marialuisa Spoletini
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, 'Sapienza' University of Rome, Rome, Italy
| | - Samanta Taurone
- Department of Sensory Organs, 'Sapienza' University of Rome, Rome, Italy
| | - Mario Tombolini
- Department of Sensory Organs, 'Sapienza' University of Rome, Rome, Italy
| | - Antonio Minni
- Department of Sensory Organs, 'Sapienza' University of Rome, Rome, Italy
| | | | | | - Felice Giangaspero
- Department of Radiology, Oncology and Anatomic Pathology, 'Sapienza' University of Rome, Rome, Italy
| | - Pier Paolo Parnigotto
- Foundation for Biology and Regenerative Medicine, Tissue Engineering and Signaling (TES) Onlus, Padua, Italy
| | - Marco Artico
- Department of Sensory Organs, 'Sapienza' University of Rome, Rome, Italy
| | - Lia Bardella
- Department of Neurology and Psychiatry, 'Sapienza' University of Rome, Rome, Italy
| | - Enzo Agostinelli
- Department of Biochemical Sciences 'A. Rossi Fanelli', 'Sapienza' University of Rome, Rome, Italy
| | - Francesco Saverio Pastore
- Department of Systems' Medicine, Division of Neurosurgery, University of Rome 'Tor Vergata', Rome, Italy
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Asa SL, Ezzat S. Gonadotrope Tumors. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 143:187-210. [PMID: 27697203 DOI: 10.1016/bs.pmbts.2016.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Gonadotrope tumors arise from the gonadotropes of the adenohypophysis. These cells rarely give rise to hyperplasia, usually only in the setting of long-standing premature gonadal failure. In contrast, gonadotrope tumors represent one of the most frequent types of pituitary tumors. Despite their relatively common occurrence, the pathogenesis of gonadotrope tumors remains unknown. Effective nonsurgical therapies remain out of reach. We review the pituitary gonadotrope from the morphologic and functional perspectives to better understand its involvement as the cell of origin of a frequent type of pituitary tumor.
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Affiliation(s)
- S L Asa
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Department of Pathology, Laboratory Medicine Program, University Health Network, Toronto, ON, Canada.
| | - S Ezzat
- Department of Medicine, University of Toronto, Endocrine Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
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Zhang L, Li H, Ge C, Li M, Zhao FY, Hou HL, Zhu MX, Tian H, Zhang LX, Chen TY, Jiang GP, Xie HY, Cui Y, Yao M, Li JJ. Inhibitory effects of transcription factor Ikaros on the expression of liver cancer stem cell marker CD133 in hepatocellular carcinoma. Oncotarget 2015; 5:10621-35. [PMID: 25301737 PMCID: PMC4279398 DOI: 10.18632/oncotarget.2524] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/24/2014] [Indexed: 12/28/2022] Open
Abstract
CD133 is a cellular surface glycoprotein that has been reported as a marker for the enrichment of cancer stem cells (CSCs). However, the regulatory mechanism of CD133 remains unknown. CSCs have been proposed to contribute to radioresistance and multi-drug resistance. The elucidation of key regulators of CD133 and CSCs is critical for the development of CSC-targeted therapy. In this study, we showed that Ikarosinhibited the expression of CD133 via direct binding to the CD133 P1 promoter and repressed the tumorigenic and self-renewal capacity of CD133(+) cancer stem-like cells in hepatocellular carcinoma (HCC). We found that Ikaros interacted with CtBP as a transcription repressor complex, which inhibited CD133 expression in HCC. We also demonstrated that Ikaros expression was up-regulated by ETS1 which activity was regulated by MAPKs pathway. Furthermore, decreased expression of Ikaroswas significantly associated with poor survival in HCC patients. Overall, our study identifies that Ikaros plays a role as a transcription repressor in HCC and is a new reactivated therapeutic target for the treatment of HCC. Meanwhile, our findings provide evidence that Ikaros could be an attractive inhibitor of the target gene CD133, which reactivates anticancer mechanisms in targeted CSC therapy.
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Affiliation(s)
- Lin Zhang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hong Li
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Chao Ge
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Meng Li
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Fang-yu Zhao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - He-lei Hou
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Miao-xin Zhu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hua Tian
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Li-xing Zhang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | | | - Guo-ping Jiang
- Department of General Surgery, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Hai-yang Xie
- Department of General Surgery, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Ying Cui
- Cancer Institute of Guangxi, Nanning, China
| | - Ming Yao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jin-jun Li
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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Ezzat S, Zheng L, Zhu XF, Wu GE, Asa SL. Retraction. Targeted expression of a human pituitary tumor-derived isoform of FGF receptor-4 recapitulates pituitary tumorigenesis. J Clin Invest 2015; 125:3303. [PMID: 26237043 DOI: 10.1172/jci83399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Gorzkiewicz A, Walczewska A. Functions of the Ikaros transcription factor and the role of IKZF1 gene defects in hematological malignancies. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.achaem.2014.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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15
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Xu XH, Huang XW, Qun L, Li YN, Wang Y, Liu C, Ma Y, Liu QM, Sun K, Qian F, Jin L, Wang J. Two functional loci in the promoter of EPAS1 gene involved in high-altitude adaptation of Tibetans. Sci Rep 2014; 4:7465. [PMID: 25501874 PMCID: PMC4264014 DOI: 10.1038/srep07465] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 11/24/2014] [Indexed: 12/21/2022] Open
Abstract
EPAS1 involves in the hypoxic response and is suggested to be responsible for the genetic adaptation of high-altitude hypoxia in Tibetans. However, the detailed molecular mechanism remains unknown. In this study, a single nucleotide polymorphism rs56721780:G>C and an insertion/deletion (indel) polymorphism -742 indel in the promoter region showed divergence between Tibetans and non-Tibetan lowlanders. rs56721780:G>C regulated the transcription of EPAS1 by IKAROS family zinc finger 1 (IKZF1), which was identified as a new transcriptional repressor for EPAS1 gene. It demonstrated that the C allele of rs56721780:G>C decreased the binding of IKZF1, leading to the attenuated transcriptional repression of EPAS1 gene. The insertion at -742 indel provided a new binding site for Sp1 and was related to the activation of EPAS1 promoter. Further functional analysis revealed that lysyl oxidase (LOX) gene, which was reported to be responsible for extracellular matrix protein cross-linking of amnion previously, was a direct target of EPAS1. The CC genotype at rs56721780:G>C and the insertion genotype at -742 indel were found associated with higher EPAS1 and LOX expression levels in amnion, as well as higher birth weight of Tibetan newborns, suggesting that EPAS1 gene might play important roles in the development of amnion, fetus growth and high-altitude adaptation of Tibetans.
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Affiliation(s)
- Xiang-Hong Xu
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China
| | - Xue-Wen Huang
- 1] Clinical laboratory of Huadong Sanatorium, Dajishan, Meiyuan Garden, Wuxi, Jiangsu 214065, P.R. China [2] Public Health Bureau for Shigatse District, 5 Keji Road, Shigatse District, Tibet 857000, P.R. China
| | - Li Qun
- Department of Gynecology and Obstetrics, The People's Hospital of Shigatse District, 28 Shanghai Middle Road, Shigatse District, Tibet 857000, P.R. China
| | - Ya-Nan Li
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China
| | - Yi Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China
| | - Chao Liu
- School of Life Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China
| | - Yanyun Ma
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China
| | - Qing-Mei Liu
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China
| | - Kang Sun
- 1] School of Life Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China [2] Center for Reproductive Medicine, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200135, P.R. China
| | - Feng Qian
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China
| | - Li Jin
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China
| | - Jiucun Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University Jiangwan Campus, 2005 Songhu Road, Shanghai 200438, P.R. China
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16
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Abstract
The genetic mutations underlying familial syndromes that include pituitary tumors are rarely noted in the majority of sporadic adenohypophyseal adenomas. In contrast, epigenetic dysregulation is common, resulting in differential expression of cell cycle and apoptosis regulators, adhesion molecules, growth factors, and metabolic determinants of cell function. Here, we discuss the diagnostic and therapeutic implications of these findings as the landscape of pituitary tumor defects unfolds.
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Affiliation(s)
- Sylvia L Asa
- Department of Pathology, University Health Network, 200 Elizabeth Street, 11th floor, Toronto, Ontario, Canada, M5G 2C4,
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17
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Nakano-Tateno T, Tateno T, Hlaing MM, Zheng L, Yoshimoto K, Yamada S, Asa SL, Ezzat S. FGFR4 polymorphic variants modulate phenotypic features of Cushing disease. Mol Endocrinol 2014; 28:525-33. [PMID: 24625004 DOI: 10.1210/me.2013-1412] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cushing disease is a potentially lethal condition resulting from hormone excess, usually due to a small pituitary tumor that fails to respond to negative feedback inhibition. A minority of patients develop larger, more aggressive tumors of the same lineage but with modest hormone excess. Here we show that a common polymorphism in the fibroblast growth factor receptor 4 (FGFR4) transmembrane domain yields receptor isoforms with distinct properties that mediate these biological differences. Forced expression of the major FGFR4-G388 variant allele supports pY-signal transducer and activator of transcription (STAT3) responses. In contrast, expression of the minor FGFR4-R388 allele enhances STAT3 serine phosphorylation, driving cellular growth. In addition, FGFR4-R388 enhances glucocorticoid receptor phosphorylation and nuclear translocation. Consistent with these findings, glucocorticoid administration resulted in enhanced hormone negative feedback in mice with knock-in of the FGFR4 variant allele. Moreover, clinical data from patients with pituitary tumors revealed that those homozygous for the R388 allele have a higher frequency of silent corticotroph macroadenomas than FGFR4-G388 carriers, who were more likely to have small but hormonally active microadenomas. These findings demonstrate that the FGFR4 transmembrane polymorphic variants can modulate cellular growth and sensitivity to glucocorticoid hormone negative feedback through distinct STAT3 modifications of relevance to the human forms of Cushing disease.
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Affiliation(s)
- Tae Nakano-Tateno
- Departments of Medicine (T.N.-T., T.T., M.M.H., L.Z., S.E.) and Laboratory Medicine and Pathobiology (T.N.-T., T.T., S.L.A.), University of Toronto, Toronto, Ontario, Canada M5S 2J7; The Endocrine Oncology Site Group (T.N.-T., T.T., S.L.A., S.E.), Princess Margaret Hospital, Toronto, Ontario, Canada M5T 2M9; Ontario Cancer Institute (T.N.-T., T.T., S.L.A., S.E.), University Health Network, Toronto, Ontario, Canada M5G-1X5; Department of Medical Pharmacology (K.Y.), Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, 770-0855, Japan; and Hypothalamic and Pituitary Surgery (S.Y.), Toranomon Hospital, Tokyo 105-0001, Japan
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18
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Ezzat S, Zheng L, Florez JC, Stefan N, Mayr T, Hliang MM, Jablonski K, Harden M, Stančáková A, Laakso M, Haring HU, Ullrich A, Asa SL. The cancer-associated FGFR4-G388R polymorphism enhances pancreatic insulin secretion and modifies the risk of diabetes. Cell Metab 2013; 17:929-940. [PMID: 23747250 PMCID: PMC4005358 DOI: 10.1016/j.cmet.2013.05.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 01/18/2013] [Accepted: 04/05/2013] [Indexed: 12/11/2022]
Abstract
The fibroblast growth factor receptor 4 (FGFR4)-R388 single-nucleotide polymorphism has been associated with cancer risk and prognosis. Here we show that the FGFR4-R388 allele yields a receptor variant that preferentially promotes STAT3/5 signaling. This STAT activation transcriptionally induces Grb14 in pancreatic endocrine cells to promote insulin secretion. Knockin mice with the FGFR4 variant allele develop pancreatic islets that secrete more insulin, a feature that is reversed through Grb14 deletion and enhanced with FGF19 administration. We also show in humans that the FGFR4-R388 allele enhances islet function and may protect against type 2 diabetes. These data support a common genetic link underlying cancer and hyperinsulinemia.
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Affiliation(s)
- Shereen Ezzat
- Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - Lei Zheng
- Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2M9, Canada
| | - Jose C Florez
- Center for Human Genetic Research and Diabetes Research Center (Diabetes Unit), Massachusetts General Hospital, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02142, USA
| | | | - Thomas Mayr
- Department of Molecular Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Maw Maw Hliang
- Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2M9, Canada
| | - Kathleen Jablonski
- The Biostatistics Center, George Washington University, Rockville, MD 20852, USA
| | - Maegan Harden
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Alena Stančáková
- Department of Medicine, University of Eastern Finland, 70210 Kuopio, Finland
| | - Markku Laakso
- Department of Medicine, University of Eastern Finland, 70210 Kuopio, Finland
| | | | - Axel Ullrich
- Department of Molecular Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Sylvia L Asa
- Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2M9, Canada
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19
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Boshnjaku V, Shim KW, Tsurubuchi T, Ichi S, Szany EV, Xi G, Mania-Farnell B, McLone DG, Tomita T, Mayanil CS. Nuclear localization of folate receptor alpha: a new role as a transcription factor. Sci Rep 2012; 2:980. [PMID: 23243496 PMCID: PMC3522071 DOI: 10.1038/srep00980] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 11/15/2012] [Indexed: 12/18/2022] Open
Abstract
Folic acid (FA) has traditionally been associated with prevention of neural tube defects; more recent work suggests that it may also be involved in in the prevention of adult onset diseases. As the role of FA in human health and disease expands, it also becomes more critical to understand the mechanisms behind FA action. In this work we examined the hypothesis that folate receptor alpha (FRα) acts as a transcription factor. FRα is a GPI-anchored protein and a component of the caveolae fraction. The work described here shows that FRα translocates to the nucleus, where it binds to cis-regulatory elements at promoter regions of Fgfr4 and Hes1, and regulates their expression. The FRα recognition domain mapped to AT rich regions on the promoters. Until this time FRα has only been considered as a folate transporter, these studies describe a novel role for FRα as a transcription factor.
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Affiliation(s)
- Vanda Boshnjaku
- Department of Pediatric Neurosurgery, Ann and Robert H Lurie Children's Hospital of Chicago Research Center and Northwestern University Feinberg School of Medicine, Chicago, IL 60614, USA
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20
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Abstract
Pituitary adenomas exhibit a wide range of behaviors. The prediction of aggressive or malignant behavior in pituitary adenomas remains challenging; however, the utility of biomarkers is rapidly evolving. In this review, we discuss potential biomarkers as they relate to aggressive behavior in pituitary adenomas. While detailed histological subtyping remains the best independent predictor of aggressive behavior in the majority of cases, evidence suggests that the additional analyses of FGFR4, MMP, PTTG, Ki-67, p53, and deletions in chromosome 11 may contribute to decisions concerning management of aggressive pituitary adenomas.
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Affiliation(s)
- Ozgur Mete
- Department of Pathology, University Health Network, 200 Elizabeth Street, 11th Floor, Toronto, Ontario, Canada.
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21
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HE LICAI, GAO FENGHOU, XU HANZHANG, ZHAO SHAN, MA CHUNMIN, LI JUNE, ZHANG SHU, WU YINGLI. Ikaros inhibits proliferation and, through upregulation of Slug, increases metastatic ability of ovarian serous adenocarcinoma cells. Oncol Rep 2012; 28:1399-405. [DOI: 10.3892/or.2012.1946] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 07/13/2012] [Indexed: 11/05/2022] Open
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22
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Tao S, Feng J, Webster T, Jin G, Hsu FC, Chen SH, Kim ST, Wang Z, Zhang Z, Zheng SL, Isaacs WB, Xu J, Sun J. Genome-wide two-locus epistasis scans in prostate cancer using two European populations. Hum Genet 2012; 131:1225-34. [PMID: 22367438 DOI: 10.1007/s00439-012-1148-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 02/12/2012] [Indexed: 12/22/2022]
Abstract
Approximately 40 single nucleotide polymorphisms (SNPs) that are associated with prostate cancer (PCa) risk have been identified through genome-wide association studies (GWAS). However, these GWAS-identified PCa risk-associated SNPs can explain only a small proportion of heritability (~13%) of PCa risk. Gene-gene interaction is speculated to be one of the major factors contributing to the so-called missing heritability. To evaluate the gene-gene interaction and PCa risk, we performed a two-stage genome-wide gene-gene interaction scan using a novel statistical approach named "Boolean Operation-based Screening and Testing". In the first stage, we exhaustively evaluated all pairs of SNP-SNP interactions for ~500,000 SNPs in 1,176 PCa cases and 1,101 control subjects from the National Cancer Institute Cancer Genetic Markers of Susceptibility (CGEMS) study. No SNP-SNP interaction reached a genome-wide significant level of 4.4E-13. The second stage of the study involved evaluation of the top 1,325 pairs of SNP-SNP interactions (P(interaction) <1.0E-08) implicated in CGEMS in another GWAS population of 1,964 PCa cases from the Johns Hopkins Hospital (JHH) and 3,172 control subjects from the Illumina iControl database. Sixteen pairs of SNP-SNP interactions were significant in the JHH population at a P(interaction) cutoff of 0.01. However, none of the 16 pairs of SNP-SNP interactions were significant after adjusting for multiple tests. The current study represents one of the first attempts to explore the high-dimensional etiology of PCa on a genome-wide scale. Our results suggested a list of SNP-SNP interactions that can be followed in other replication studies.
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Affiliation(s)
- Sha Tao
- Center for Genetic Epidemiology and Prevention, Van Andel Research Institute, Grand Rapids, MI, USA
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23
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Dorman K, Shen Z, Yang C, Ezzat S, Asa SL. CtBP1 interacts with Ikaros and modulates pituitary tumor cell survival and response to hypoxia. Mol Endocrinol 2012; 26:447-57. [PMID: 22301782 DOI: 10.1210/me.2011-1095] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
C-terminal binding protein (CtBP) is a transcriptional corepressor that plays an important role in mammalian development and tumorigenesis. We demonstrate that CtBP is expressed in adenohypophyseal cells and is expressed at high levels in human corticotroph, somatotroph, and lactotroph pituitary adenomas. CtBP interacts with Ikaros isoforms in GH4 and AtT20 pituitary tumor cells. Ikaros and CtBP1 expression is coordinately induced by hypoxia, and this response is abrogated by CtBP1 deficiency. Forced reduction of CtBP1 leads to reduced cell growth, up-regulation of Sprouty 2, and down-regulation of ectonucleotide pyrophosphatase phosphodiesterase 2 (Enpp2). Consistent with diminished Enpp2 activity, CtBP1-deficient pituitary cells are more susceptible to hypoxia-induced apoptosis, which is rescued by Enpp2-derived lysophosphatidic acid treatment. These results identify putative oncogenic properties of CtBP1 and provide new insights into the overlapping functions of two members of the chromatin remodeling network in the response to hypoxic pituitary tumor cell drive.
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Affiliation(s)
- Katie Dorman
- Departments of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
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24
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Tateno T, Asa SL, Zheng L, Mayr T, Ullrich A, Ezzat S. The FGFR4-G388R polymorphism promotes mitochondrial STAT3 serine phosphorylation to facilitate pituitary growth hormone cell tumorigenesis. PLoS Genet 2011; 7:e1002400. [PMID: 22174695 PMCID: PMC3234213 DOI: 10.1371/journal.pgen.1002400] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 10/17/2011] [Indexed: 12/21/2022] Open
Abstract
Pituitary tumors are common intracranial neoplasms, yet few germline abnormalities have been implicated in their pathogenesis. Here we show that a single nucleotide germline polymorphism (SNP) substituting an arginine (R) for glycine (G) in the FGFR4 transmembrane domain can alter pituitary cell growth and hormone production. Compared with FGFR4-G388 mammosomatotroph cells that support prolactin (PRL) production, FGFR4-R388 cells express predominantly growth hormone (GH). Growth promoting effects of FGFR4-R388 as evidenced by enhanced colony formation was ascribed to Src activation and mitochondrial serine phosphorylation of STAT3 (pS-STAT3). In contrast, diminished pY-STAT3 mediated by FGFR4-R388 relieved GH inhibition leading to hormone excess. Using a knock-in mouse model, we demonstrate the ability of FGFR4-R385 to promote GH pituitary tumorigenesis. In patients with acromegaly, pituitary tumor size correlated with hormone excess in the presence of the FGFR4-R388 but not the FGFR4-G388 allele. Our findings establish a new role for the FGFR4-G388R polymorphism in pituitary oncogenesis, providing a rationale for targeting Src and STAT3 in the personalized treatment of associated disorders. Several human cancers have been associated with increased growth hormone levels. Here we show that a frequent single nucleotide polymorphism (SNP) associated with increased cancer risk and progression also deregulates pituitary function. Through recruitment of a distinct STAT3 signaling cascade, this polymorphic receptor variant drives pituitary growth hormone cell survival and hormonal output. These findings provide an example of a potentially common genetic program shared between cancer and a hormone that promotes its progression.
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Affiliation(s)
- Toru Tateno
- Ontario Cancer Institute, University Health Network, Toronto, Canada
- The Endocrine Oncology Site Group, Princess Margaret Hospital, Toronto, Canada
- Department of Medicine, University of Toronto, Toronto, Canada
| | - Sylvia L. Asa
- Ontario Cancer Institute, University Health Network, Toronto, Canada
- The Endocrine Oncology Site Group, Princess Margaret Hospital, Toronto, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Lei Zheng
- Ontario Cancer Institute, University Health Network, Toronto, Canada
- The Endocrine Oncology Site Group, Princess Margaret Hospital, Toronto, Canada
- Department of Medicine, University of Toronto, Toronto, Canada
| | - Thomas Mayr
- Department of Molecular Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Axel Ullrich
- Department of Molecular Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Shereen Ezzat
- Ontario Cancer Institute, University Health Network, Toronto, Canada
- The Endocrine Oncology Site Group, Princess Margaret Hospital, Toronto, Canada
- Department of Medicine, University of Toronto, Toronto, Canada
- * E-mail:
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25
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Li Z, Perez-Casellas LA, Savic A, Song C, Dovat S. Ikaros isoforms: The saga continues. World J Biol Chem 2011; 2:140-5. [PMID: 21765980 PMCID: PMC3135861 DOI: 10.4331/wjbc.v2.i6.140] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 05/05/2011] [Accepted: 05/12/2011] [Indexed: 02/05/2023] Open
Abstract
Through alternate splicing, the Ikaros gene produces multiple proteins. Ikaros is essential for normal hematopoiesis and possesses tumor suppressor activity. Ikaros isoforms interact to form dimers and potentially multimeric complexes. Diverse Ikaros complexes produced by the presence of different Ikaros isoforms are hypothesized to confer distinct functions. Small dominant-negative Ikaros isoforms have been shown to inhibit the tumor suppressor activity of full-length Ikaros. Here, we describe how Ikaros activity is regulated by the coordinated expression of the largest Ikaros isoforms IK-1 and IK-H. Although IK-1 is described as full-length Ikaros, IK-H is the longest Ikaros isoform. IK-H, which includes residues coded by exon 3B (60 bp that lie between exons 3 and 4), is abundant in human but not murine hematopoietic cells. Specific residues that lie within the 20 amino acids encoded by exon 3B give IK-H DNA-binding characteristics that are distinct from those of IK-1. Moreover, IK-H can potentiate or inhibit the ability of IK-1 to bind DNA. IK-H binds to the regulatory regions of genes that are upregulated by Ikaros, but not genes that are repressed by Ikaros. Although IK-1 localizes to pericentromeric heterochromatin, IK-H can be found in both pericentromeric and non-pericentromeric locations. Anti-silencing activity of gamma satellite DNA has been shown to depend on the binding of IK-H, but not other Ikaros isoforms. The unique features of IK-H, its influence on Ikaros activity, and the lack of IK-H expression in mice suggest that Ikaros function in humans may be more complex and possibly distinct from that in mice.
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Affiliation(s)
- Zhanjun Li
- Zhanjun Li, Chunhua Song, Sinisa Dovat, Department of Pediatrics, Pennsylvania State University,College of Medicine, H085, Division of Pediatric Hematology/Oncology, Hershey, PA 17033-0850, United States
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26
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Song C, Li Z, Erbe AK, Savic A, Dovat S. Regulation of Ikaros function by casein kinase 2 and protein phosphatase 1. World J Biol Chem 2011; 2:126-31. [PMID: 21765978 PMCID: PMC3135859 DOI: 10.4331/wjbc.v2.i6.126] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 04/29/2011] [Accepted: 05/06/2011] [Indexed: 02/05/2023] Open
Abstract
The Ikaros gene encodes a zinc finger, DNA-binding protein that regulates gene transcription and chromatin remodeling. Ikaros is a master regulator of hematopoiesis and an established tumor suppressor. Moderate alteration of Ikaros activity (e.g. haploinsufficiency) appears to be sufficient to promote malignant transformation in human hematopoietic cells. This raises questions about the mechanisms that normally regulate Ikaros function and the potential of these mechanisms to contribute to the development of leukemia. The focus of this review is the regulation of Ikaros function by phosphorylation/dephosphorylation. Site-specific phosphorylation of Ikaros by casein kinase 2 (CK2) controls Ikaros DNA-binding ability and subcellular localization. As a consequence, the ability of Ikaros to regulate cell cycle progression, chromatin remodeling, target gene expression, and thymocyte differentiation are controlled by CK2. In addition, hyperphosphorylation of Ikaros by CK2 leads to decreased Ikaros levels due to ubiquitin-mediated degradation. Dephosphorylation of Ikaros by protein phosphatase 1 (PP1) acts in opposition to CK2 to increase Ikaros stability and restore Ikaros DNA binding ability and pericentromeric localization. Thus, the CK2 and PP1 pathways act in concert to regulate Ikaros activity in hematopoiesis and as a tumor suppressor. This highlights the importance of these signal transduction pathways as potential mediators of leukemogenesis via their role in regulating the activities of Ikaros.
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Affiliation(s)
- Chunhua Song
- Chunhua Song, Zhanjun Li, Sinisa Dovat, Department of Pediatrics, Pennsylvania State University, College of Medicine, Hershey, PA 17033-0850, United States
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27
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Ebrahimi A, Schittenhelm J, Honegger J, Schluesener HJ. Histone acetylation patterns of typical and atypical pituitary adenomas indicate epigenetic shift of these tumours. J Neuroendocrinol 2011; 23:525-30. [PMID: 21453398 DOI: 10.1111/j.1365-2826.2011.02129.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Pituitary adenomas are benign endocrine tumours of the anterior pituitary that are subclassified as typical (conventional) or atypical adenomas, with uncertain prognosis based on histopathological features. Clarifying epigenetic alterations of pituitary tumours, as well as the mechanisms underlying them, will hopefully open new windows to treatment and the classification of these tumours and maybe even prediction of patient survival. In the present study, using immunohistochemistry, we investigated the acetylation pattern of histone 3 lysine 9 (H3K9), an epigenetic marker of active chromatin state and gene transcription, in typical and atypical pituitary adenomas and the normal pituitary. We observed a significant increase in H3K9 acetylation from the normal pituitary to typical and atypical pituitary adenomas, which was associated with significant hyperacetylation of H3K9 in atypical adenomas (P < 0.0001). MIB-1 (Ki-67) overexpression was also highly associated with increased acetylation of H3K9, correlating prositively with tumour severity (P < 0.0001). p53 overexpression had a contributing effect on altered global H3K9 acetylation of atypical pituitary adenomas (P < 0.05). These data suggests that H3K9 acetylation status might serve as a relevant additional biomarker of tumour severity in pituitary adenomas, and also as a proper target for epigenetic-based therapies.
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Affiliation(s)
- A Ebrahimi
- Division of Immunopathology of the Nervous System, Department of Neuropathology, Institute of Pathology and Neuropathology, University of Tuebingen, Tuebingen, Germany.
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28
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Xekouki P, Azevedo M, Stratakis CA. Anterior pituitary adenomas: inherited syndromes, novel genes and molecular pathways. Expert Rev Endocrinol Metab 2010; 5:697-709. [PMID: 21264206 PMCID: PMC3024595 DOI: 10.1586/eem.10.47] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Pituitary adenomas are common tumors. Although rarely malignant, pituitary adenomas cause significant morbidity due to mass effects and/or hormonal hypo- and/or hyper-secretion. Molecular understanding of pituitary adenoma formation is essential for the development of medical therapies and the treatment of post-operative recurrences. In general, mutations in genes involved in genetic syndromes associated with pituitary tumors are not a common finding in sporadic lesions. By contrast, multiple endocrine neoplasia type 1 (MEN-1) and aryl hydrocarbon receptor-interacting protein (AIP) mutations may be more frequent among specific subgroups of patients, such as children and young adults, with growth hormone-producing adenomas. In this article, we present the most recent data on the molecular pathogenesis of pituitary adenomas and discuss some of the most recent findings from our laboratory. Guidelines for genetic screening and clinical counseling of patients with pituitary tumors are provided.
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Affiliation(s)
- Paraskevi Xekouki
- SEGEN, PDEGEN & Pediatric Endocrinology Program, NICHD, NIH, Building 10, CRC (East Laboratories), Room 1-3330, 10 Center Drive, MSC1103, Bethesda, MD 20892, USA
| | - Monalisa Azevedo
- SEGEN, PDEGEN & Pediatric Endocrinology Program, NICHD, NIH, Building 10, CRC (East Laboratories), Room 1-3330, 10 Center Drive, MSC1103, Bethesda, MD 20892, USA
| | - Constantine A Stratakis
- SEGEN, PDEGEN & Pediatric Endocrinology Program, NICHD, NIH, Building 10, CRC (East Laboratories), Room 1-3330, 10 Center Drive, MSC1103, Bethesda, MD 20892, USA
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29
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Zhu X, Asa SL, Ezzat S. Histone-acetylated control of fibroblast growth factor receptor 2 intron 2 polymorphisms and isoform splicing in breast cancer. Mol Endocrinol 2009; 23:1397-405. [PMID: 19497954 DOI: 10.1210/me.2009-0071] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Recent genome-wide association studies have identified fibroblast growth factor receptor (FGFR)2 as one of a few candidate genes linked with breast cancer susceptibility. In particular, the disease-predisposing allele of FGFR2 is inherited as a 7.5-kb region within intron 2 that harbors eight single nucleotide polymorphisms. The relationship between these single nucleotide polymorphisms and FGFR2 gene expression remains unclear. Here we show the common occurrence of polymorphisms within the intron 2 region in a panel of 10 breast cancer cell lines. High FGFR2-expressing cell lines such as MCF-7 cells displayed polymorphic sequences with constitutive histone acetylation at multiple intron 2 sequences harboring putative transcription binding sites. Knockdown of Runx2 or CCAAT enhancer binding protein beta in these cells resulted in diminished endogenous FGFR2 gene expression. In contrast FGFR2-negative MDA-231 cells were wild type and showed evidence of histone 3/4 deacetylation at the rs2981578, rs10736303, and rs7895676 disease-associated alleles that harbor binding sites for Runx2, estrogen receptor, and CCAAT enhancer binding protein beta, respectively. Histone deacetylation inhibition with trichostatin A resulted in enhanced acetylation at these intron 2 sites, an effect associated with robust FGFR2 reexpression. Isoform analysis proved reexpression of the FGFR2-IIIc variant the splicing of which was positively influenced by trichostatin A-mediated recruitment of the Fas-activated serine/threonine phosphoprotein survival protein. Our findings highlight the potential role of histone acetylation in modulating access to selected polymorphic sites within intron 2 as well as downstream splicing sites in generating variable FGFR2 levels and isoforms in breast cancer.
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Affiliation(s)
- Xuegong Zhu
- Department of Medicine, and the Endocrine Oncology Site Group, Princess Margaret Hospital, Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G 2M9
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30
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Asa SL, Ezzat S. The pathogenesis of pituitary tumors. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2009; 4:97-126. [PMID: 19400692 DOI: 10.1146/annurev.pathol.4.110807.092259] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Recently there has been significant progress in our understanding of pituitary development, physiology, and pathology. New information has helped to clarify the classification of pituitary tumors. Epidemiologic analyses have identified a much higher incidence of pituitary tumors than previously thought. We review the pathogenetic factors that have been implicated in pituitary tumorigenesis and the application of novel targeted therapies that underscore the increasingly important role of the pathologist in determining accurate diagnoses and facilitating appropriate treatment of patients with these disorders.
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Affiliation(s)
- Sylvia L Asa
- Department of Laboratory Medicine and Pathobiology, University of Toronto, University Health Network and Ontario Cancer Institute, Toronto, Ontario, Canada.
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31
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Roidl A, Berger HJ, Kumar S, Bange J, Knyazev P, Ullrich A. Resistance to chemotherapy is associated with fibroblast growth factor receptor 4 up-regulation. Clin Cancer Res 2009; 15:2058-66. [PMID: 19240166 DOI: 10.1158/1078-0432.ccr-08-0890] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Establishment of antiapoptotic signaling pathways in tumor cells is a major cause for the failure of chemotherapy against cancer. To investigate the underlying mechanisms, we developed an experimental approach that is based on the genetic plasticity of cancer cells and the selection for cell survival on treatment with chemotherapeutic agents. EXPERIMENTAL DESIGN Gene expression changes of surviving cell clones were analyzed by macroarrays. Involvement of fibroblast growth factor receptor 4 (FGFR4) in antiapoptotic pathways was elucidated by apoptosis assays, small interfering RNA experiments, and an antagonistic antibody. RESULTS We show that FGFR4 gene expression is up-regulated in doxorubicin-treated, apoptosis-resistant cancer cell clones. Ectopic expression of FGFR4 in cancer cells led to reduced apoptosis sensitivity on treatment with doxorubicin or cyclophosphamide, whereas knockdown of endogenous FGFR4 expression in breast cancer cell lines had the opposite effect. FGFR4 overexpression resulted in Bcl-xl up-regulation at both mRNA and protein levels. Knockdown of FGFR4 expression by small interfering RNA caused a decrease in phospho-extracellular signal-regulated kinase 1/2 levels and reduced Bcl-xl expression. Moreover, an antagonistic FGFR4 antibody suppressed the resistance of cancer cells with endogenous FGFR4 expression against apoptosis-inducing chemotherapeutic agents. CONCLUSION Based on these findings, we propose an antiapoptotic signaling pathway that is initiated by FGFR4 and regulating the expression of Bcl-xl through the mitogen-activated protein kinase cascade. Our findings are exemplary for a novel strategy toward the elucidation of diverse signaling pathways that define antiapoptotic potential in cancer cells. These observations open new avenues toward the diagnosis of chemoresistant tumors and therapies targeting FGFR4-overexpressing cancers.
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Affiliation(s)
- Andreas Roidl
- Department of Molecular Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany
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32
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Abstract
Epigenetically-mediated gene dysregulation is a common feature associated with human pituitary tumorigenesis. The mechanisms leading to these changes, however, remain largely unknown. In this review, we examine changes responsible for DNA and histone modifications as independent, butpotentially interrlated modes of communication effecting chromatin remodeling. The dynamic properties of the enzymes involved in these reactions is highlighted. We use the fibroblast growth factor receptor 2 (FGFR2) as a model through which the p53-regulating melanoma-associated antigen (MAGE) system is governing in pituitary cells. The pathogenetic and potential therapeutic implications are discussed.
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Affiliation(s)
- Shereen Ezzat
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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Zhu X, Mao X, Hurren R, Schimmer AD, Ezzat S, Asa SL. Deoxyribonucleic acid methyltransferase 3B promotes epigenetic silencing through histone 3 chromatin modifications in pituitary cells. J Clin Endocrinol Metab 2008; 93:3610-7. [PMID: 18544619 DOI: 10.1210/jc.2008-0578] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT AND OBJECTIVE Epigenetic dysregulation is implicated in pituitary neoplasia as the cause of silencing of several tumor suppressor genes. However, the upstream mediators of such events remain unknown. DESIGN We examined the three members of the DNA methyltransferase (DNMT) enzyme family in normal and neoplastic human and mouse pituitary cells. SETTING This study was performed at a university-affiliated cancer research institute. MAIN OUTCOME MEASURES Gene expression, promoter DNA methylation, histone modifications, and cell proliferation were determined. RESULTS In contrast to DNMT1 and DNMT3a, DNMT3b was expressed at relatively higher levels in neoplastic pituitary cells. However, examination of the human DNMT3b 5' region showed uniformly low DNA methylation levels with little difference between normal and tumor samples. Through pharmacological methylation inhibition or histone deacetylation inhibition, we identified that DNMT3b gene expression is subject to histone modifications. Down-regulation of DNMT3b resulted in induction of retinoblastoma, p21, and p27, and reduction in cell proliferation. These targeted effects were associated with enhanced histone 3 acetylation and diminished histone methylation. CONCLUSION Our findings identify DNMT3b as a putative mediator of epigenetic control through histone modifications of gene expression in pituitary cells.
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Affiliation(s)
- Xuegong Zhu
- Department of Medicine, University Health Network, The Ontario Cancer Institute, 610 University Avenue 8-327, Toronto, Ontario, Canada M5G 2M9
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Ruiz A, Williams O, Brady HJM. The Ikaros splice isoform, Ikaros 6, immortalizes murine haematopoietic progenitor cells. Int J Cancer 2008; 123:1240-5. [PMID: 18623087 DOI: 10.1002/ijc.23706] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alternative pre-mRNA splicing is emerging as a major control point in both the initiation and progression of tumourigenesis. Overexpression of the dominant negative Ikaros splice isoform, Ik6, is found in many human cancers particularly leukaemias. Ik6 has been demonstrated to have a role in cell survival in both myeloid- and lymphoid cytokine-dependent cell lines. To investigate the oncogenic potential of Ik6, we retrovirally transduced murine haematopoietic progenitor cells with Ik6 and have analysed the effects on proliferation and differentiation of these precursors using myeloid and lymphoid in vitro colony formation assays. We found that Ik6 can immortalize haematopoietic progenitor cells in myeloid conditions. Using an in vivo transplantation assay, we found that Ik6 favours reconstitution by haematopoietic precursors. These findings suggest that Ik6 may play an important role in the generation of the leukaemic phenotype.
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Affiliation(s)
- Anna Ruiz
- Molecular Haematology and Cancer Biology Unit, Institute of Child Health, University College London, London, United Kingdom
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Kano G, Morimoto A, Takanashi M, Hibi S, Sugimoto T, Inaba T, Yagi T, Imashuku S. Ikaros dominant negative isoform (Ik6) induces IL-3-independent survival of murine pro-B lymphocytes by activating JAK-STAT and up-regulating Bcl-xl levels. Leuk Lymphoma 2008; 49:965-73. [PMID: 18464116 DOI: 10.1080/10428190801993462] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ikaros is an essential regulator of lymphocyte differentiation. Mice transgenic for the Ikaros dominant negative (DN) mutation rapidly develop lymphoid malignancies. Various human leukemias have also been reported to express Ikaros DN isoforms, but its role in leukemogenesis is yet to be defined. We demonstrate that overexpressed Ikaros DN (Ik6) prolonged the survival of two different murine pro-B cell lines in cytokine deprived condition, and this was associated with increased expression of Bcl-xl. A survey of the upstream controller(s) of Bcl-xl expression revealed Ik6 overexpression enhanced the phosphorylation of JAK2 and STAT5. Interestingly, the Ik6 expressing cell lines showed reduced expression of B-cell differentiation surface marker CD45R (B220), which is also known as a JAK2 inhibitor. Although further evaluation with human clinical materials are required, these results propose a putative role of Ik6 in the development of B-lineage acute lymphoblastic leukemia, by activating the JAK2-STAT5 pathway and thus stimulating the production of Bcl-xl.
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Affiliation(s)
- Gen Kano
- Department of Paediatrics, Kyoto Prefectural University of Medicine, Japan
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36
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Zhu X, Asa SL, Ezzat S. Fibroblast growth factor 2 and estrogen control the balance of histone 3 modifications targeting MAGE-A3 in pituitary neoplasia. Clin Cancer Res 2008; 14:1984-96. [PMID: 18381936 DOI: 10.1158/1078-0432.ccr-07-2003] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Four members of the fibroblast growth factor receptor (FGFR) family transduce signals of a diverse group of FGF ligands. The FGFR2-IIIb isoform is abundantly present in the normal pituitary gland with contrasting down-regulation in neoplastic pituitary cells. cDNA profiling identified the cancer-testis antigen melanoma-associated antigen A3 (MAGE-A3) as a putative target negatively regulated by FGFR2. EXPERIMENTAL DESIGN Comparisons were made between normal and neoplastic human and mouse pituitary cells. Gene expression was examined by reverse transcription-PCR, DNA methylation was determined by methylation-specific PCR and combined bisulfite restriction analysis, and histone modification marks were identified by chromatin immunoprecipitation. RESULTS Normal human pituitary tissue that expresses FGFR2-IIIb does not express MAGE-A3; in contrast, pituitary tumors that are FGFR2 negative show abundant MAGE-A3 mRNA expression. MAGE-A3 expression correlates with the presence and extent of DNA promoter methylation; more frequent and higher-degree methylation is present in the normal gland compared with pituitary tumors. Conversely, pituitary tumors are hypomethylated, particularly in females where MAGE-A3 expression is nearly thrice higher than in males. Estradiol treatment induces MAGE-A3 through enhanced histone 3 acetylation and diminished methylation. The effects of estradiol are directly opposed by FGF7/FGFR2-IIIb. Down-regulation of MAGE-A3 results in p53 transcriptional induction, also through reciprocal histone acetylation and methylation modifications. CONCLUSIONS These findings highlight MAGE-A3 as a target of FGFR2-IIIb and estrogen action and provide evidence for a common histone-modifying network in the control of the balance between opposing signals.
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Affiliation(s)
- Xuegong Zhu
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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37
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Loeper S, Asa SL, Ezzat S. Ikaros modulates cholesterol uptake: a link between tumor suppression and differentiation. Cancer Res 2008; 68:3715-23. [PMID: 18483254 DOI: 10.1158/0008-5472.can-08-0103] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ikaros is a transcription factor that directs lymphoid lineage commitment and pituitary neuroendocrine cell expansion and function. Here, we show that Ikaros regulates the low-density lipoprotein receptor (LDL-R) to alter metabolism in pituitary corticotroph cells. The DNA-binding Ikaros isoform Ik1 binds and enhances activity of the LDL-R promoter. Ik1 decreases methylation and increases acetylation of histone H3 (Lys(9)) at the LDL-R promoter. Confocal microscopy and quantitative fluorometry show enhanced LDL endocytosis in Ik1-transfected cells that exhibit abundant endoplasmic reticulum, large Golgi complexes, and prominent secretory granule formation, consistent with more robust cholesterol incorporation into functionally relevant membrane-rich organelles. Consistent with these data, LDL-R(-/-) mice, like Ik(-/-) mice, have decreased circulating levels of adrenocorticotropic hormone. These findings expand the repertoire of Ikaros actions to include regulation of the cholesterol uptake metabolic pathway with therapeutic implications for lipid-modifying drugs in Ikaros-associated cancers.
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Affiliation(s)
- Siobhan Loeper
- Departments of Medicine and Pathology, University Health Network, Ontario Cancer Institute, Toronto, Ontario, Canada
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38
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Mice lacking the transcription factor Ikaros display behavioral alterations of an anti-depressive phenotype. Exp Neurol 2008; 211:107-14. [DOI: 10.1016/j.expneurol.2008.01.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Accepted: 01/11/2008] [Indexed: 11/23/2022]
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Horvath A, Stratakis CA. Clinical and molecular genetics of acromegaly: MEN1, Carney complex, McCune-Albright syndrome, familial acromegaly and genetic defects in sporadic tumors. Rev Endocr Metab Disord 2008; 9:1-11. [PMID: 18200440 DOI: 10.1007/s11154-007-9066-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Pituitary tumors are among the most common neoplasms in man; they account for approximately 15% of all primary intracranial lesions (Jagannathan et al., Neurosurg Focus, 19:E4, 2005). Although almost never malignant and rarely clinically expressed, pituitary tumors may cause significant morbidity in affected patients. First, given the critical location of the gland, large tumors may lead to mass effects, and, second, proliferation of hormone-secreting pituitary cells leads to endocrine syndromes. Acromegaly results from oversecretion of growth hormone (GH) by the proliferating somatotrophs. Despite the significant efforts made over the last decade, still little is known about the genetic causes of common pituitary tumors and even less is applied from this knowledge therapeutically. In this review, we present an update on the genetic syndromes associated with pituitary adenomas and discuss the related genetic defects. We next review findings on sporadic, non-genetic, pituitary tumors with an emphasis on pathways and animal models of pituitary disease. In conclusion, we attempt to present an overall, integrative approach to the human molecular genetics of both familiar and sporadic pituitary tumors.
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Affiliation(s)
- Anelia Horvath
- Section on Endocrinology and Genetics, Program on Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1103, USA
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40
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Boikos SA, Stratakis CA. Molecular genetics of the cAMP-dependent protein kinase pathway and of sporadic pituitary tumorigenesis. Hum Mol Genet 2007; 16 Spec No 1:R80-7. [PMID: 17613552 DOI: 10.1093/hmg/ddm019] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Pituitary tumors are among the most common human neoplasms. Although these common lesions rarely become clinically manifest and they are almost never malignant, they are the cause of significant morbidity in affected patients. The genetic causes of common pituitary tumors remain for the most part unknown; progress has been limited to the elucidation of the molecular etiology of four genetic syndromes predisposing to pituitary neoplasias: McCune-Albright syndrome, multiple endocrine neoplasia type 1, Carney complex and, most recently, familial acromegaly and prolactinomas and other tumors caused by mutations in the GNAS, menin, PRKAR1A, AIP, and p27 (CDKN1B) genes, respectively. Intense molecular studies of sporadic pituitary tumors from patients with negative family histories and no other neoplasms have yielded interesting findings with abnormalities in growth factor expression and cell cycle control dysregulation. To add to the difficulties in understanding pituitary tumorigenesis in man, good murine models of these neoplasms simply do not exist: pituitary tumors are common in rodents, but their histologic origin (mostly from the intermediate lobe), age of presentation (late in murine life) and clinical course make them hardly models of their human counterparts. The present report reviews the clinical and molecular genetics of the cAMP-dependent protein kinase pathway in human pituitary tumors; it also reviews briefly other pathways that have been involved in sporadic pituitary neoplasms. At the end, we attempt a unifying hypothesis for pituitary tumorigenesis, taking into account data that are also discussed elsewhere in this issue.
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Affiliation(s)
- Sosipatros A Boikos
- Section on Endocrinology and Genetics (SEGEN), Developmental Endocrinology Branch (DEB), National Institute of Child Health and Human Development (NICHD), National Institues of Health, Bethesda, MD 20892-1103, USA
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41
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Kondo T, Zhu X, Asa SL, Ezzat S. The cancer/testis antigen melanoma-associated antigen-A3/A6 is a novel target of fibroblast growth factor receptor 2-IIIb through histone H3 modifications in thyroid cancer. Clin Cancer Res 2007; 13:4713-20. [PMID: 17699848 DOI: 10.1158/1078-0432.ccr-07-0618] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Fibroblast growth factor (FGF) signals play fundamental roles in development and tumorigenesis. Thyroid cancer is an example of a tumor with nonoverlapping genetic mutations that up-regulate mitogen-activated protein kinase. We reported recently that FGF receptor 2 (FGFR2) is down-regulated through extensive DNA promoter methylation in thyroid cancer. Reexpression of the FGFR2-IIIb isoform impedes signaling upstream of the BRAF/mitogen-activated protein kinase pathway to interrupt tumor progression. In this analysis, we examined a novel target of FGFR2-IIIb signaling, melanoma-associated antigen-A3 and A6 (MAGE-A3/6). EXPERIMENTAL DESIGN cDNA microarray analysis was done on human WRO thyroid cancer cells transfected with FGFR2-IIIb or empty vector. Identified gene target was confirmed by reverse transcription-PCR and Western blotting. Gene regulation was examined by treatment of WRO cells with the methylation inhibitor 5'-azacytidine followed by methylation-specific PCR and reverse transcription-PCR and by chromatin immunoprecipitation. RESULTS Gene expression profiling identified the cancer/testis antigen MAGE-A3/6 as a novel target of FGFR2-IIIb signaling. MAGE-A3/6 regulation was mediated through DNA methylation and chromatin modifications. In particular, FGF7/FGFR2-IIIb activation resulted in histone 3 methylation and deacetylation associated with the MAGE-A3/6 promoter to down-regulate gene expression. CONCLUSIONS These data unmask a complex repertoire of epigenetically controlled signals that govern FGFR2-IIIb and MAGE-A3/6 expression. Our findings provide insights into the interrelationship between novel tumor markers that may also represent overlapping therapeutic targets.
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Affiliation(s)
- Tetsuo Kondo
- Department of Pathology, Princess Margaret Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
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42
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Zhu X, Lee K, Asa SL, Ezzat S. Epigenetic silencing through DNA and histone methylation of fibroblast growth factor receptor 2 in neoplastic pituitary cells. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:1618-28. [PMID: 17456767 PMCID: PMC1854956 DOI: 10.2353/ajpath.2007.061111] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/06/2007] [Indexed: 01/07/2023]
Abstract
Four members of the fibroblast growth factor receptor (FGFR) family of tyrosine kinases transduce signals of a diverse group of more than 23 fibroblast growth factor (FGF) ligands. Each prototypic receptor is composed of three immunoglobulin-like extracellular domains, two of which are involved in ligand binding. Alternative RNA splicing of one of two exons results in two different forms of the second half of the third immunoglobulin-like domain, the IIIb or IIIc isoforms. The contribution of each receptor and their isoforms in tumorigenesis remains unknown. In the pituitary, FGFR2 is expressed primarily as the IIIb isoform in normal adenohypophysial cells. In contrast, FGFR2 is significantly down-regulated in mouse corticotroph AtT20 tumor cells where the 5' promoter is methylated. Treatment of AtT20 cells with 5'-azacytidine resulted in FGFR2 re-expression, mainly as the FGFR2-IIIb isoform. Chromatin immunoprecipitation revealed evidence of histone methylation, but not of deacetylation, in the silencing of FGFR2 in AtT20 cells. Exposure of these cells to the cognate FGFR2-IIIb ligand FGF-7 resulted in diminished Rb phosphorylation and accumulation of p21 and p27, indicating diminished cell cycle progression. Examination of primary human pituitary adenomas revealed FGFR2 down-regulation in 52% (11 of 21) of samples and FGFR2 promoter DNA methylation in 45% (10 of 22) of samples. These data highlight the contribution from DNA and histone methylation as epigenetic mechanisms responsible for FGFR2 silencing in pituitary neoplasia.
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Affiliation(s)
- Xuegong Zhu
- Department of Medicine, Mount Sinai Hospital and University of Toronto, Canada
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43
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Zhu X, Asa SL, Ezzat S. Ikaros Is Regulated through Multiple Histone Modifications and Deoxyribonucleic Acid Methylation in the Pituitary. Mol Endocrinol 2007; 21:1205-15. [PMID: 17341593 DOI: 10.1210/me.2007-0053] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
The transcription factor Ikaros (Ik) is at the center of a functionally diverse chromatin-remodeling network that is critical for the development and regulation of both the immune and endocrine systems. Dominant negative forms of Ik result in neoplastic growth in mouse genetic studies and have been identified in human tumors. Ik modulates chromatin accessibility through associations with members of the NURD complex including histone deacetylase complexes. We show here that Ik expression in mouse pituitary corticotroph cells is itself regulated through histone modifications as well as DNA methylation. Examination of primary human pituitary specimens also identified a correlation of loss of Ik expression with the presence of DNA methylation in the untranslated exon 1 CpG island. These findings have important implications for the understanding of Ikaros’ role in epigenetic functions and suggest a potential role for demethylating agents in the treatment of related disorders.
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Affiliation(s)
- Xuegong Zhu
- Department of Medicine, Mount Sinai Hospital and University of Toronto, Canada
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44
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Ezzat S, Asa SL. Mechanisms of disease: The pathogenesis of pituitary tumors. ACTA ACUST UNITED AC 2006; 2:220-30. [PMID: 16932287 DOI: 10.1038/ncpendmet0159] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Accepted: 12/29/2005] [Indexed: 11/08/2022]
Abstract
Pituitary tumors exhibit a spectrum of biology, with variable growth and hormonal behaviors. They therefore provide an opportunity to examine pathogenetic mechanisms that underlie the neoplastic process. These include alterations in hormone regulation, growth-factor stimulation, cell-cycle control and cell-stromal interactions that result from genetic mutations or epigenetic disruption of gene expression. Mouse models have validated the roles of these alterations, which can be targets for the development of therapies that can manage these lesions. These therapies are increasingly recognized as critical for quality of life.
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Affiliation(s)
- Shereen Ezzat
- The Freeman Centre for Endocrine Oncology, Mount Sinai Hospital, Toronto, Ontario, Canada
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45
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Ezzat S, Zheng L, Winer D, Asa SL. Targeting N-cadherin through fibroblast growth factor receptor-4: distinct pathogenetic and therapeutic implications. Mol Endocrinol 2006; 20:2965-75. [PMID: 16857743 DOI: 10.1210/me.2006-0223] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Several molecular aberrations have been implicated in the pathogenesis of pituitary tumors, but few have proven thus far to be of therapeutic value. Pituitary tumor-derived fibroblast growth factor receptor-4 (ptd-FGFR4) is an alternatively transcribed cytoplasmic isoform lacking most of the extracellular domain. This oncogene recapitulates the morphological features of human pituitary tumors in transgenic mice. To investigate the therapeutic potential of targeting ptd-FGFR4, we examined the impact of FGFR4 tyrosine kinase inhibition in xenografted mice. GH4 pituitary cells expressing ptd-FGFR4 develop into invasive tumors. Systemic treatment of mice bearing ptd-FGFR4 tumors with the FGFR-selective inhibitor PD173074 resulted in recovery of membranous N-cadherin staining and a significant reduction in tumor volume with less invasive growth behavior. Mutation of tyrosine Y754F in ptd-FGFR4 abrogated the effect of PD173074-mediated inhibition. The pivotal role of N-cadherin as a mediator of this pituitary cell growth was demonstrated by small interfering RNA mediated down-regulation, which promoted invasive growth in xenografted mice. To validate this model in primary human pituitary tumors, we examined the expression of ptd-FGFR4, N-cadherin, and clinical behavior. Loss of membranous N-cadherin correlated with cytoplasmic FGFR4 expression and with tumor invasiveness in surgically resected human pituitary tumors. Primary human pituitary tumor cells treated with PD173074 showed restoration of N-cadherin to the membrane with dephosphorylation of retinoblastoma protein. These data highlight the pathogenetic significance of N-cadherin misexpression and emphasize the importance of FGFR partnership in mediating its functions.
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MESH Headings
- Adenoma/drug therapy
- Adenoma/etiology
- Adenoma/metabolism
- Animals
- Antineoplastic Agents/therapeutic use
- Brain Neoplasms/metabolism
- Cadherins/metabolism
- Cadherins/physiology
- Cell Proliferation/drug effects
- Cells, Cultured
- Disease Progression
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Mice
- Mice, SCID
- Models, Biological
- Neoplasm Invasiveness
- Neoplasm Proteins/antagonists & inhibitors
- Neoplasm Proteins/physiology
- Pituitary Neoplasms/drug therapy
- Pituitary Neoplasms/etiology
- Pituitary Neoplasms/metabolism
- Protein Isoforms/antagonists & inhibitors
- Protein Isoforms/physiology
- Protein Kinase Inhibitors/therapeutic use
- Pyrimidines/pharmacology
- Pyrimidines/therapeutic use
- Rats
- Receptor, Fibroblast Growth Factor, Type 4/antagonists & inhibitors
- Receptor, Fibroblast Growth Factor, Type 4/metabolism
- Receptor, Fibroblast Growth Factor, Type 4/physiology
- Somatotrophs
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Shereen Ezzat
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
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46
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Ezzat S, Mader R, Fischer S, Yu S, Ackerley C, Asa SL. An essential role for the hematopoietic transcription factor Ikaros in hypothalamic-pituitary-mediated somatic growth. Proc Natl Acad Sci U S A 2006; 103:2214-9. [PMID: 16467156 PMCID: PMC1413703 DOI: 10.1073/pnas.0508565103] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Ikaros transcription factors play critical functions in the control of lymphohematopoiesis and immune regulation. Family members contain multiple zinc fingers that mediate DNA binding and homooligomerization or heterooligomerization. Ikaros is abundantly expressed in pituitary mammosomatotrophs, where it deacetylates histone 3 sites on the proximal growth hormone (GH) promoter to silence gene expression. Ikaros-null mice display stunted growth with reduced circulating levels of the GH target factor insulin-like growth factor I (IGF-I). Ikaros-deficient mice have small anterior pituitary glands with a disproportionately reduced somatotroph population. Systemic administration of GH results in increased IGF-I levels and enhanced somatic growth. In contrast, reconstitution with WT lymphocytes was not sufficient to rescue the stunted growth phenotype of Ikaros-deficient mice. Ikaros was identified in mouse hypothalamic arcuate nuclei, where it colocalized with GH-releasing hormone (GHRH); in contrast, Ikaros-null mice lack GHRH immunoreactivity in the hypothalamus. Overexpression of Ikaros enhanced GHRH promoter activity and induced endogenous GHRH gene expression. These findings unmask a wider role for Ikaros in the neuroendocrine system, highlighting a critical contribution to the development of the hypothalamic-pituitary somatotrophic axis.
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Affiliation(s)
- Shereen Ezzat
- *Department of Medicine, Mount Sinai Hospital
- The Freeman Centre for Endocrine Oncology and Ontario Cancer Institute, University of Toronto, 610 University Avenue, Toronto, ON, Canada M5G 2M9
- To whom correspondence should be addressed at:
Ontario Cancer Institute, University of Toronto, 610 University Avenue, 8-327, Toronto, ON, Canada, M5G-2M9. E-mail:
or
| | - Rene Mader
- Department of Pathology, University Health Network
- The Freeman Centre for Endocrine Oncology and Ontario Cancer Institute, University of Toronto, 610 University Avenue, Toronto, ON, Canada M5G 2M9
| | - Sandra Fischer
- Department of Pathology, University Health Network
- The Freeman Centre for Endocrine Oncology and Ontario Cancer Institute, University of Toronto, 610 University Avenue, Toronto, ON, Canada M5G 2M9
| | - ShunJiang Yu
- *Department of Medicine, Mount Sinai Hospital
- The Freeman Centre for Endocrine Oncology and Ontario Cancer Institute, University of Toronto, 610 University Avenue, Toronto, ON, Canada M5G 2M9
| | | | - Sylvia L. Asa
- Department of Pathology, University Health Network
- The Freeman Centre for Endocrine Oncology and Ontario Cancer Institute, University of Toronto, 610 University Avenue, Toronto, ON, Canada M5G 2M9
- To whom correspondence should be addressed at:
Ontario Cancer Institute, University of Toronto, 610 University Avenue, 8-327, Toronto, ON, Canada, M5G-2M9. E-mail:
or
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47
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Abstract
It is becoming increasingly evident that cell adhesion is an important determinant of organised growth and the maintenance of architectural integrity. Indeed, reduced adhesiveness between cells and with the extracellular matrix is a hallmark of neoplastic growth. In neuroendocrine tissues, neural cell adhesion molecule is implicated in modulating cell growth, migration, and differentiation. This review will focus on the molecular pathways involving key growth factor receptors that govern normal adhesive forces. The extent to which disruption of these adhesive forces contributes to the tumorigenic process in neuroendocrine tissues will be highlighted. Validation of the functional relevance of these adhesive pathways will be discussed in light of targeted pharmacotherapeutic studies that are unmasking novel approaches to the treatment of neuroendocrine tumours.
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Affiliation(s)
- S Ezzat
- Department of Medicine, University of Toronto, Endocrine Oncology Site Group, Mount Sinai and Princess Margaret Hospitals, Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada M5G-1X5.
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48
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Al-Shraim M, Asa SL. The 2004 World Health Organization classification of pituitary tumors: what is new? Acta Neuropathol 2006; 111:1-7. [PMID: 16328527 DOI: 10.1007/s00401-005-1093-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Revised: 05/17/2005] [Accepted: 05/18/2005] [Indexed: 01/16/2023]
Abstract
The classification of pituitary tumors is a dynamic area that changes with advances in cell biology that provide a deeper insight and clearer understanding of cell lineages and pathogenetic mechanisms. The 2004 edition of the World Heath Organization (WHO) text "Histological typing of endocrine tumors" reflects the progress that has been achieved since the previous edition of 2000. Here we review the new information and identify areas of concern for the next effort at classification of pituitary tumors.
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Affiliation(s)
- Mubarak Al-Shraim
- Department of Pathology, University Health Network and Toronto Medical Laboratories, University of Toronto, Toronto, Ontario, M5G 2M9, Canada
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49
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Abstract
Genetics and proteomics determine structure and function of normal tissues, and the molecular alterations that underlie tumorigenesis result in changes in these aspects of tissue biology in neoplasms. We review the known genetic alterations in pituitary tumors. These include the oncogenic Gsalpha protein (GSP)-activating mutations, and pituitary tumor-derived fibroblast growth factor receptor-4 (ptd-FGFR4), as well as tumor suppressor gene mutations associated with multiple endocrine neoplasia type 1 (MEN1). Other candidates identified from expression profiling include pituitary tumor-transforming gene (PTTG), GADD45, and bone morphogenic protein (BMP)4. Proteomic changes in pituitary tumors include classical alterations identified by immunohistochemistry as well as epigenetic reductions in p27. The underlying mechanisms for dysregulated cell adhesive molecules including cadherins and FGFRs are reviewed. The combined use of genetic and proteomic approaches will enhance novel drug therapeutic development.
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Affiliation(s)
- Sylvia L Asa
- Endocrine Oncology Site Group, Mount Sinai and Princess Margaret Hospitals, University of Toronto, Toronto, Ontario, Canada.
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50
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Principles of Functioning of the Machinery of Transcription Initiation by RNA Polymerase II. RUSS J GENET+ 2005. [DOI: 10.1007/s11177-005-0186-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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