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Carcinoma of the colon and rectum with deregulation of insulin-like growth factor 2 signaling: clinical and molecular implications. J Gastroenterol 2016; 51:971-84. [PMID: 26984550 DOI: 10.1007/s00535-016-1181-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 02/02/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND Loss of imprinting (LOI) of the insulin-like growth factor 2 (IGF2) is an early event in the development of colorectal cancer (CRC). Whether LOI of IGF2 denotes a molecular or clinical cancer subgroup is currently unknown. METHODS Tumor biopsies and paired normal mucosa from 399 patients with extensive clinical annotations were analyzed for LOI and IGF2 expression. LOI status in 140 informative cases was correlated with clinicopathologic parameters and outcome. RESULTS LOI was frequent in normal mucosa and tumors and occurred throughout the large intestine. LOI was unrelated to microsatellite instability, KRAS mutation status, stage, and survival. However, CRC with LOI showed increased IGF2 protein levels and activation of AKT1. Gene expression analysis of tumors with and without LOI and knockdown of IGF2 in cell lines revealed that IGF2 induced distinct sets of activated and repressed genes, including Wnt5a, CEACAM6, IGF2BP3, KPN2A, BRCA2, and CDK1. Inhibition of AKT1 in IGF2-stimulated cells showed that the downstream effects of IGF2 on cell proliferation and gene expression were strictly AKT1-dependent. CONCLUSIONS LOI of IGF2 is a frequent and early event in CRC that occurs both in the adenomatous polyposis coli (APC) gene-mutated and serrated route of carcinogenesis. LOI leads to overexpression of IGF2, activates IGF1R and AKT1, and is a powerful driver of cell proliferation. Moreover, our results suggest that IGF2 via AKT1 also contributes to non-canonical wnt signaling. Although LOI had no significant impact on major clinical parameters and outcome, its potential as a target for preventive and therapeutic interventions merits further investigation.
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Shin DH, Min HY, El-Naggar AK, Lippman SM, Glisson B, Lee HY. Akt/mTOR counteract the antitumor activities of cixutumumab, an anti-insulin-like growth factor I receptor monoclonal antibody. Mol Cancer Ther 2011; 10:2437-48. [PMID: 21980128 DOI: 10.1158/1535-7163.mct-11-0235] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent reports have shown limited anticancer therapeutic efficacy of insulin-like growth factor receptor (IGF-1R)-targeted monoclonal antibodies (mAb), but the resistance mechanisms have not been completely identified. Because cooperation between epidermal growth factor receptor (EGFR) and IGF-IR could cause resistance to inhibitors of individual receptor tyrosine kinases, we investigated the involvement of EGFR signaling in resistance to IGF-1R mAb and the underlying mechanisms of action. Most head and neck squamous cell carcinoma (HNSCC) tissues had coexpression of total and phosphorylated IGF-1R and EGFR at high levels compared with paired adjacent normal tissues. Treatment with cixutumumab (IMC-A12), a fully humanized IgG1 mAb, induced activation of Akt and mTOR, resulting in de novo synthesis of EGFR, Akt1, and survivin proteins and activation of the EGFR pathway in cixutumumab-resistant HNSCC and non-small cell lung cancer (NSCLC) cells. Targeting mTOR and EGFR pathways by treatment with rapamycin and cetuximab (an anti-EGFR mAb), respectively, prevented cixutumumab-induced expression of EGFR, Akt, and survivin and induced synergistic antitumor effects in vitro and in vivo. These data show that resistance to IGF-1R inhibition by mAbs is associated with Akt/mTOR-directed enhanced synthesis of EGFR, Akt1, and survivin. Our findings suggest that Akt/mTOR might be effective targets to overcome the resistance to IGF-1R mAbs in HNSCC and NSCLC.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Humanized
- Carcinoma, Non-Small-Cell Lung/drug therapy
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/metabolism
- Carcinoma, Squamous Cell/drug therapy
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/metabolism
- Drug Antagonism
- Drug Resistance, Neoplasm/genetics
- Head and Neck Neoplasms/drug therapy
- Head and Neck Neoplasms/genetics
- Head and Neck Neoplasms/metabolism
- Humans
- Lung Neoplasms/drug therapy
- Lung Neoplasms/genetics
- Lung Neoplasms/metabolism
- Mice
- Mice, Nude
- Proto-Oncogene Proteins c-akt/genetics
- Proto-Oncogene Proteins c-akt/metabolism
- Proto-Oncogene Proteins c-akt/physiology
- Receptor, IGF Type 1/antagonists & inhibitors
- Receptor, IGF Type 1/immunology
- Squamous Cell Carcinoma of Head and Neck
- TOR Serine-Threonine Kinases/genetics
- TOR Serine-Threonine Kinases/metabolism
- TOR Serine-Threonine Kinases/physiology
- Tumor Cells, Cultured
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Dong Hoon Shin
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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Zumkeller W. The role of insulin-like growth factor system in soft tissue sarcomas: from physiopathology to targeted therapeutic approaches. Sarcoma 2011; 2:69-76. [PMID: 18521237 PMCID: PMC2395388 DOI: 10.1080/13577149878028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Purpose/Results. Although surgical, chemo- and radiotherapeutic treatment regimens in patients with soft tissue sarcomas have constantly been refined over the past two decades, the survival rate for these patients is rather low. Discussion. There is a great need to investigate the mechanisms for oncogenesis and to identify the factors involved in malignant transformation in sarcomas. Among these factors, IGFs are thought to play a pivotal role as progression factors in various types of sarcomas. The dysregulation of the IGF-II synthesis, e.g. by loss of imprinting which occurs in most
types of sarcomas, is a permissive effect through the suppression of cell death. In addition, cells that overexpress the type I IGF receptors are more susceptible to transformation by oncogenes. As TP53 suppresses the activity of IGF-II P3 and P4, as well as the type I IGF receptor promoter, mutations of TP53 in sarcomas may alternatively lead to the activation of these factors. Finally, the phenomenon of non-islet cell tumour hypoglycaemia that occurs in patients with sarcomas, and which is related to the secretion of IGF-II prohormones, is discussed. Future therapeutic strategies may be based upon the application of antibodies or antisense oligonucleotides directed against the type I IGF receptors, with the common goal of inducing apoptosis in sarcoma cells. Ultimately, these and other therapeutic approaches may lead to a better outcome in patients suffering from sarcoma.
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Affiliation(s)
- W Zumkeller
- Department of Hematology/Oncology Children's University Hospital Heidelberg Germany
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Lawson EA, Zhang X, Crocker JT, Wang WL, Klibanski A. Hypoglycemia from IGF2 overexpression associated with activation of fetal promoters and loss of imprinting in a metastatic hemangiopericytoma. J Clin Endocrinol Metab 2009; 94:2226-31. [PMID: 19383775 DOI: 10.1210/jc.2009-0153] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The mechanism of IGF2 overexpression in non-islet-cell tumor hypoglycemia is not understood. OBJECTIVE We investigated the imprinting control and promoter usage for IGF2 expression to identify a mechanism for increased IGF-II production in non-islet-cell tumor hypoglycemia. PATIENT AND METHODS A patient with metastatic hemangiopericytoma was studied. Tissue from the original hemangiopericytoma, metastatic tumor, and uninvolved liver was analyzed for IGF-II immunohistochemistry. IGF2, a paternally imprinted gene, shares a control region with maternally imprinted H19, a putative tumor suppressor. IGF-II and H19 mRNA expression was compared in metastatic tumor and uninvolved liver by quantitative RT-PCR. Imprinting of IGF2/H19 genes and IGF2 promoter usage in metastatic tumor was investigated by RT-PCR and sequence analysis, and the methylation pattern in the IGF2/H19 imprinting control region was analyzed. RESULTS IGF-II protein expression was increased in metastatic tumor vs. uninvolved liver and original tumor. In the metastatic tumor, IGF-II mRNA was increased 60-fold, but H19 mRNA was comparable to uninvolved liver; loss of imprinting of IGF2, but not H19, was identified; no major change in methylation of the IGF2/H19 imprinting control regions was observed; and transcripts from four different IGF2 promoters were detected, compared to two in uninvolved liver. CONCLUSIONS IGF-2 overexpression, newly acquired in the metastatic tumor, was associated with loss of IGF2 gene imprinting and different promoter usage. The imprinting control mechanism governing the IGF2/H19 locus was intact, as evidenced by normal levels of H19, maintenance of H19 imprinting, and no major change in methylation of the imprinting control regions.
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Affiliation(s)
- Elizabeth A Lawson
- Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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Corcoran RB, Bachar Raveh T, Barakat MT, Lee EY, Scott MP. Insulin-like growth factor 2 is required for progression to advanced medulloblastoma in patched1 heterozygous mice. Cancer Res 2008; 68:8788-95. [PMID: 18974121 DOI: 10.1158/0008-5472.can-08-2135] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Medulloblastoma (MB) can arise in the cerebellum due to genetic activation of the Sonic Hedgehog (Shh) signaling pathway. During normal cerebellum development, Shh spurs the proliferation of granule neuron precursors (GNP), the precursor cells of MB. Mutations in the Shh receptor gene patched1 (ptc1+/-) lead to increased MB incidence in humans and mice. MB tumorigenesis in mice heterozygous for ptc1+/- shows distinct steps of progression. Most ptc1+/- mice form clusters of preneoplastic cells on the surface of the mature cerebellum that actively transcribe Shh target genes. In approximately 15% of mice, these preneoplastic cells will become fast-growing, lethal tumors. It was previously shown that the loss of function of insulin-like growth factor 2 (igf2) suppresses MB formation in ptc1+/- mice. We found that igf2 is not expressed in preneoplastic lesions but is induced as these lesions progress to more advanced MB tumors. Igf2 is not required for formation of preneoplastic lesions but is necessary for progression to advanced tumors. Exogenous Igf2 protein promoted proliferation of MB precursor cells (GNP) and a MB cell line, PZp53(MED). Blocking igf2 signaling inhibited growth of PZp53(MED) cells, implicating igf2 as a potential clinical target.
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Affiliation(s)
- Ryan B Corcoran
- Department of Developmental Biology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305, USA
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Möller B, Kerschbaumer G, Komor M, Kerschbaumer F, Ottmann OG, Hoelzer D, Hofmann WK. Genomic imprinting of insulin-like growth factor 2 (IGF-2) in chronic synovitis. Growth Horm IGF Res 2007; 17:500-505. [PMID: 17590364 DOI: 10.1016/j.ghir.2007.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 05/10/2007] [Accepted: 05/15/2007] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To search for relaxation or loss of IGF-2 imprinting (LOI) in rheumatoid arthritis (RA) synovial tissues. DESIGN The genotype of IGF-2 was determined in 25 freshly isolated synovial tissue samples with signs of active inflammation by polymerase chain reaction (PCR) and restriction fragment length polymorphism. Imprinting was determined in synovial tissue mononuclear cells (STMC) of five informative heterozygous patients by reverse transcriptase (RT)-PCR. Mitogen-stimulated peripheral blood mononuclear cells (PBMC) from six informative healthy donors were selected for control. RESULTS In vitro proliferation of CD4+ and CD8+ PB T cells, and also of CD19+ PB B cells was detectable upon mitogen stimulation. Furthermore, MHC II molecule expression on synovial B and T cells indicated in vivo cell activation. Monoallelic IGF-2 expression was seen in PBMC cultures from two healthy donors under both, resting and stimulating conditions. In two other PBMC cultures, LOI occurred exclusively after 24 h of stimulation. PBMC from two other healthy donors showed LOI under both, resting and stimulating conditions. Mitogen induced and spontaneous LOI was reversible in each one PBMC culture after 72 h. In contrast, none of the informative STMC cultures showed LOI. CONCLUSIONS LOI in lymphocytes may occur spontaneously or inducible. However, longstanding activation of lymphocytes in RA synovitis appears not to be related to this mechanism.
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Affiliation(s)
- B Möller
- Inselspital - University Hospital Bern, Klinik für Rheumatologie, klinische Immunologie und Allergologie, CH-3010 Bern, Switzerland.
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Engström W, Shokrai A, Otte K, Granérus M, Gessbo A, Bierke P, Madej A, Sjölund M, Ward A. Transcriptional regulation and biological significance of the insulin like growth factor II gene. Cell Prolif 2007; 31:173-89. [PMID: 9925986 PMCID: PMC6647699 DOI: 10.1111/j.1365-2184.1998.tb01196.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The insulin like growth factors I and II are the most ubiquitous in the mammalian embryo. Moreover they play a pivotal role in the development and growth of tumours. The bioavailability of these growth factors is regulated on a transcriptional as well as on a posttranslational level. The expression of non-signalling receptors as well as binding proteins does further tune the local concentration of IGFs. This paper aims at reviewing how the transcription of the IGF genes is regulated. The biological significance of these control mechanisms will be discussed.
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Affiliation(s)
- W Engström
- Department of Pathology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Lu L, Katsaros D, Wiley A, Rigault de la Longrais IA, Puopolo M, Schwartz P, Yu H. Promoter-specific transcription of insulin-like growth factor-II in epithelial ovarian cancer. Gynecol Oncol 2006; 103:990-5. [PMID: 16859738 DOI: 10.1016/j.ygyno.2006.06.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 06/02/2006] [Accepted: 06/07/2006] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The IGF-II gene has four promoters (P1-P4); each initiates promoter-specific transcription. Studies have shown that IGF-II promoters normally active during fetal growth, but silent in postnatal life, are reactivated in cancer. In a previous study, we found IGF-II transcription evaluated at a common translated region was associated with ovarian cancer progression. This study was conducted to further determine which IGF-II promoters were responsible for the association. METHODS Promoter-specific transcription at each IGF-II promoter was analyzed in 201 ovarian tumor samples using quantitative RT-PCR. Cox regression analysis was performed to determine the association of IGF-II promoter-specific expression with patient survival. RESULTS P3 and P4 transcripts were detected more frequently and at significantly higher levels than the transcripts of P1 and P2. P3 and P4 transcripts were strongly correlated with the common IGF-II translated region and were significantly higher in patients with late stage disease, large residual tumor, suboptimal debulking or serous histology compared to those with early stage, small residual tumor, optimal debulking or non-serous histology. Survival analysis showed that patients with high P3 or P4 expression had a 2-fold increase in risk for death compared to those with low P3 or P4. These associations remained significant after adjustment for patient age at surgery, disease stage, tumor grade and histology. P1 and P2 transcripts, however, were not associated with disease characteristics or survival. CONCLUSIONS These findings suggest that IGF-II transcription from P3 and P4 promoters is important in ovarian cancer and evaluation of IGF-II promoter-specific transcription may have clinical implications in ovarian cancer prognosis and treatment.
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Affiliation(s)
- Lingeng Lu
- Department of Epidemiology, Yale Cancer Center, Yale University School of Medicine, 60 College Street, New Haven, CT 06520-8034, USA
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Grbesa I, Ivkic M, Pegan B, Gall-Troselj K. Loss of imprinting and promoter usage of the IGF2 in laryngeal squamous cell carcinoma. Cancer Lett 2006; 238:224-9. [PMID: 16111804 DOI: 10.1016/j.canlet.2005.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 07/07/2005] [Accepted: 07/08/2005] [Indexed: 10/25/2022]
Abstract
The gene for insulin-like growth factor two, IGF2 is maternally imprinted. Fifteen heterozygous samples were analyzed for the IGF2 imprinting status and promoter usage. IGF2 LOI was detected in four non-tumorous tissues and in six laryngeal squamous cell carcinoma (LSCC) tumors. There was no clear pattern of specific promoter activity in LSCC tumors and the adjacent normal tissues. P1 promoter usage was active in eight LSCCs, among them four with LOI. As it was activated in four tumors with maintenance of imprinting (MOI) and four non-tumors, we concluded that P1 promoter is not exclusively connected with IGF2 LOI in LSCC.
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Affiliation(s)
- Ivana Grbesa
- Laboratory of Molecular Pathology, Division of Molecular Medicine, Rudjer Boskovic Institute, Bijenicka cesta 54, 10002 Zagreb, Croatia.
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12
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Abstract
Medulloblastoma (MB), a tumor of the cerebellum, is the most frequent type of malignant childhood brain tumor. Multiple genes are causally involved in medulloblastoma including PATCHED1 (PTCH). The Patchedl (Ptc1) protein is a receptor for Sonic hedgehog (Shh), a secreted protein ligand. Shh is involved in many signaling processes that control cell fate and growth, among which is its emission from Purkinje cells in the developing cerebellum. Purkinje cell-derived Shh stimulates mitosis of the granule cell precursors that may be the cell type of origin in medulloblastoma. Ptc1 limits the effects of the Shh signal, so mutations in PTCH may lead to persistent granule cell precursors susceptible to further genetic or environmental events that cause medulloblastoma. Mice heterozygous for patched (ptc1) mutations, like heterozygous PTCH humans, have a high rate of medulloblastoma as well as other tumors. We discuss features of the mouse model and how it is contributing to understanding the process of brain tumorigenesis.
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Affiliation(s)
- R B Corcoran
- Department of Developmental Biology, Howard Hughes Medical Institute, Beckman Center, Stanford University School of Medicine, CA, USA
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Svaren J, Ehrig T, Abdulkadir SA, Ehrengruber MU, Watson MA, Milbrandt J. EGR1 target genes in prostate carcinoma cells identified by microarray analysis. J Biol Chem 2000; 275:38524-31. [PMID: 10984481 DOI: 10.1074/jbc.m005220200] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The EGR1 transactivator is overexpressed in prostate cancer, and its expression pattern suggests that EGR1 could potentially regulate a number of steps involved in initiation and progression of prostate cancer, such as mitogenesis, invasiveness, angiogenesis, and metastasis. To identify potential EGR1 target genes in an unbiased manner, we have utilized adenovirus-mediated expression of EGR1 in a prostate cancer cell line to identify specific genes that are induced by EGR1. Using oligonucleotide arrays, a number of EGR1-regulated genes were identified and their regulation was confirmed by quantitative reverse transcription-polymerase chain reaction analysis. One of the largest gene classes identified in this screen includes several neuroendocrine-associated genes (neuron-specific enolase, neurogranin), suggesting that EGR1 overexpression may contribute to the neuroendocrine differentiation that often accompanies prostate cancer progression. This screen also identified several growth factors such as insulin-like growth factor-II, platelet-derived growth factor-A, and transforming growth factor-beta1, which have previously been implicated in enhancing tumor progression. The insulin-like growth factor-II gene lies within the 11p15.5 chromosomal locus, which contains a number of other imprinted genes, and EGR1 expression was found to induce at least two other genes in this locus (IPL, p57(KIP2)). Based on our results, coupling adenoviral overexpression with microarray and quantitative reverse transcription-polymerase chain reaction analyses could be a versatile strategy for identifying target genes of transactivators.
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Affiliation(s)
- J Svaren
- Departments of Pathology and Internal Medicine, Division of Laboratory Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Adriaenssens E, Dumont L, Lottin S, Bolle D, Leprêtre A, Delobelle A, Bouali F, Dugimont T, Coll J, Curgy JJ. H19 overexpression in breast adenocarcinoma stromal cells is associated with tumor values and steroid receptor status but independent of p53 and Ki-67 expression. THE AMERICAN JOURNAL OF PATHOLOGY 1998; 153:1597-607. [PMID: 9811352 PMCID: PMC1853398 DOI: 10.1016/s0002-9440(10)65748-3] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/24/1998] [Indexed: 01/10/2023]
Abstract
In a previous study we described the expression of the H19 gene by in situ hybridization (ISH) in normal breast and in benign or malignant breast tumors (Dugimont T, Curgy JJ, Wernert N, Delobelle A, Raes MB, Joubel A, Stehelin D, Coll J: Biol Cell 1995, 85:117-124). In the present work, 1) we extend the previous one to a statistically useful number of adenocarcinomas, including 10 subclasses, 2) we provide information on the precise ISH localization of the H19 RNA by using, on serial tissue sections, antibodies delineating specifically the stromal or the epithelial component of the breast, and 3) we consider relationships between the H19 gene expression and various clinicopathological information as tumor values (T0 to T4), grades, steroid receptors, lymph node status, and molecular features as the p53 gene product and the Ki-67/MIB1 protein, which is specific to proliferating cells. Data indicate that 1) in 72.5% of studied breast adenocarcinomas an overall H19 gene expression is increased when compared with healthy tissues, 2) the H19 gene is generally overexpressed in stromal cells (92.2%) and rarely in epithelial cells (2.9% only), 3) an up-regulation of the H19 gene is significantly correlated with the tumor values and the presence of both estrogen and progesterone receptors, and 4) at the cellular level, the H19 gene demonstrates an independent expression versus accumulation of both the p53 protein and the Ki-67/MIB-1 cell-cycle marker.
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Affiliation(s)
- E Adriaenssens
- Centre de Biologie Cellulaire, Université des Sciences et Technologies de Lille, Vileneuve d'Ascq, France
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Zhan S, Zhang L, Van M, Young C, Helman LJ. Biallelic expression of all four IGF-II promoters and its association with increased methylation of H19 gene in human brain. Brain Res 1998; 792:283-90. [PMID: 9593943 DOI: 10.1016/s0006-8993(98)00157-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The human IGF-II gene is maternally imprinted in all tissues except adult liver and the choroid plexus/leptomeninges of the central nervous system where IGF-II is biallelically expressed. In human liver, it has recently been reported that this biallelic expression only involves the promoter P1 while the promoters P2-P4 direct IGF-II transcription monoallelically. To explore whether or not biallelic expression of the IGF-II promoters in human CNS displays the same pattern as in liver, we examined the allelic expression status of the four IGF-II promoters in human brain. We found that all four IGF-II promoters in human fetal and adult brain were expressed from both parental alleles. Furthermore, the levels of methylation of the 3' region of H19 gene in fetal brain were higher than those in other tissues with monoallelic expression of IGF-II. Since similar findings have been reported in Wilms' tumor, these data suggest a similar mechanism may be responsible for loss of imprinting of IGF-II in normal brain and Wilms' tumor.
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Affiliation(s)
- S Zhan
- Pediatric Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Hahn H, Wojnowski L, Zimmer AM, Hall J, Miller G, Zimmer A. Rhabdomyosarcomas and radiation hypersensitivity in a mouse model of Gorlin syndrome. Nat Med 1998; 4:619-22. [PMID: 9585239 DOI: 10.1038/nm0598-619] [Citation(s) in RCA: 311] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Gorlin (or nevoid basal cell carcinoma) syndrome is characterized by a variety of clinical problems including generalized overgrowth of the body, cysts, developmental abnormalities of the skeleton and a predisposition to benign and malignant tumors. The syndrome results from germline mutations of the human homolog of the drosophila segment polarity gene patched (ptc). Here we report that mice heterozygous for ptc develop many of the features characteristic of Gorlin syndrome and that they exhibit a high incidence of rhabdomyosarcomas (RMS), the most common soft-tissue sarcoma in children. The downstream signalling partner of ptc, gli1, was overexpressed in all RMSs analyzed, indicating that abnormal signalling of the ptc-gli1 pathway may be common for the various tumors associated with the syndrome. igf2, implicated in the formation of RMSs, was also overexpressed, suggesting cross-talk between the ptc and igf2 pathways in tumorigenesis. Developmental defects in Gorlin syndrome resemble those induced by ionizing radiation. We show that ptc heterozygous mice exhibit increased incidence of radiation-induced teratogenesis. This suggests a role for ptc in the response to ionizing radiation and provides a model for both the systemic (developmental) and stochastic (cancer) abnormalities observed in Gorlin syndrome.
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Affiliation(s)
- H Hahn
- Section on Genetics, National Institute of Mental Health, Bethesda, MD 20892, USA
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Roy RN, Cecutti A, Gerulath AH, Steinberg WM, Bhavnani BR. Endometrial transcripts of human insulin-like growth factors arise by differential promoter usage. Mol Cell Endocrinol 1997; 135:11-9. [PMID: 9453236 DOI: 10.1016/s0303-7207(97)00181-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
By the application of RT-PCR, we have demonstrated that in the human endometrium mRNAs for insulin-like growth factors, IGF-I and II, and their receptors are expressed not only in the intact endometrium, but also in the freshly isolated stromal and epithelial cells. The expression of multiple transcript forms of the IGF-I and II at various phases of the menstrual cycle, occurs by differential use of all four IGF-I transcriptional start sites, and two of the four known promoter sites of the IGF-II gene. The complete spectrum of transcripts is displayed by the proliferative phase and the menstrual phase endometrium. During the secretory phase, the exon 1 upstream start site of the IGF-I gene and the P2 promoter of the IGF-II gene are not used. Irrespective of the phase of the menstrual cycle, the stromal cells always display the same transcriptional patterns of both growth factor genes as those of the intact endometrium. In contrast, the epithelial cells do not express IGF-I transcript originating from the exon 2 upstream initiation site. These results indicate that the expressions of the IGF-I and II genes in the intact endometrium and stromal and epithelial cells are modulated at the transcriptional level during the menstrual cycle by differential usage of promoters and start sites.
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Affiliation(s)
- R N Roy
- Department of Obstetrics and Gynecology, St. Michael's Hospital and Institute of Medical Sciences, University of Toronto, Ontario, Canada
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Hu JF, Vu TH, Hoffman AR. Genomic deletion of an imprint maintenance element abolishes imprinting of both insulin-like growth factor II and H19. J Biol Chem 1997; 272:20715-20. [PMID: 9252392 DOI: 10.1074/jbc.272.33.20715] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Insulin-like growth factor II (Igf2) is maternally imprinted in normal tissues with only the paternal copy of the gene being transcribed, whereas the contiguous gene H19 is paternally imprinted. Dysregulation of IGF2 imprinting is commonly observed in Wilms' tumor and other human tumors. Previous work comparing promoter-specific imprinting of human and mouse Igf2 suggested the presence of a cis element upstream of Igf2 that regulates or maintains the imprinting of three downstream promoters. To explore the molecular mechanism of maintenance of genomic imprinting, we targeted the region between insulin 2 and Igf2, where the cis imprint maintenance element (IME) resides in mouse fibroblasts. In those clones in which the targeting vector was randomly integrated into the genome, mouse Igf2 remained imprinted. However, when the targeted region containing the IME was deleted by homologous recombination, whether from the paternal or maternal allele, activation of the imprinted maternal allele of Igf2 was observed. In addition, there was a loss of H19 imprinting when the IME was deleted. The requirement of IME from both parental alleles for the maintenance of genomic imprinting thus suggests the importance of a spatial structure of DNA around Igf2 and H19. Modifications in the IME, like abnormal methylation in Wilms' tumors, may represent a novel mechanism for loss of genomic imprinting.
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Affiliation(s)
- J F Hu
- Medical Service and GRECC, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304, USA
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Uchida K, Kondo M, Takeda S, Osada H, Takahashi T, Nakao A, Takahashi T. Altered transcriptional regulation of the insulin-like growth factor 2 gene in human hepatocellular carcinoma. Mol Carcinog 1997. [DOI: 10.1002/(sici)1098-2744(199704)18:4<193::aid-mc2>3.0.co;2-f] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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20
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Abstract
Parental imprinting is a process that results in allele-specific differences in transcription, DNA methylation, and DNA replication timing. Imprinting plays an important role in development, and its deregulation can cause certain defined disease states. Absence of a paternal contribution to chromosome 15q11-q13, due to hemizygous deletion or uniparental disomy, results in the Prader-Willi syndrome. The absence of a normal maternal copy of the same region causes Angelman syndrome. The Beckwith-Wiedemann syndrome is associated with the failure of normal biparental inheritance of chromosome 11p15, and loss of imprinting is observed in several cancers including Wilms' tumor. The study of the molecular basis of abnormal imprinting in these disorders will facilitate the identification and characterization of other imprinted human disease loci.
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Affiliation(s)
- M Lalande
- Howard Hughes Medical Institute, Genetics Division, Children's Hospital, Boston, Massachusetts, USA.
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Wang WH, Duan JX, Vu TH, Hoffman AR. Increased expression of the insulin-like growth factor-II gene in Wilms' tumor is not dependent on loss of genomic imprinting or loss of heterozygosity. J Biol Chem 1996; 271:27863-70. [PMID: 8910385 DOI: 10.1074/jbc.271.44.27863] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Loss of imprinting of insulin-like growth factor-II gene (IGF2) and/or loss of heterozygosity at the 11p15 loci have been postulated to be responsible for IGF2 overexpression in Wilms' tumor. In order to delineate the mechanism of IGF2 overexpression in Wilms' tumors, we have genotyped the 11p15-11p13 chromosomal region and determined allelic expression of IGF2 and H19 in both tumor tissue and in normal adjacent kidney tissue from 40 patients with Wilms' tumor. In five of the eight subjects informative for the ApaI IGF2 polymorphism, loss of imprinting of IGF2 was observed in both normal and tumor tissues. A significant increase (>5-fold) in IGF2 expression in tumor tissues compared to the normal adjacent kidney tissue was observed regardless of the IGF2 imprinting or the chromosome 11p15 heterozygosity status. In each case, the overexpression of IGF2 in the tumors was accompanied by activation of all four IGF2 promoters. Our data indicate that alterations of IGF2 imprinting occurred in normal adjacent kidney tissue before tumorigenesis and that the IGF2 overexpression in Wilms' tumor tissue occurs through a loss of heterozygosity- or loss of imprinting-independent process.
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Affiliation(s)
- W H Wang
- Medical Service and GRECC, Veterans Affairs Palo Alto Health Care System and Department of Medicine, Stanford University School of Medicine, Palo Alto, California 94304, USA.
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22
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Issa JP, Vertino PM, Boehm CD, Newsham IF, Baylin SB. Switch from monoallelic to biallelic human IGF2 promoter methylation during aging and carcinogenesis. Proc Natl Acad Sci U S A 1996; 93:11757-62. [PMID: 8876210 PMCID: PMC38131 DOI: 10.1073/pnas.93.21.11757] [Citation(s) in RCA: 199] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We have previously linked aging, carcinogenesis, and de novo methylation within the promoter of the estrogen receptor (ER) gene in human colon. We now examine the dynamics of this process for the imprinted gene for insulin-like growth factor II (IGF2). In young individuals, the P2-4 promoters of IGF2 are methylated exclusively on the silenced maternal allele. During aging, this promoter methylation becomes more extensive and involves the originally unmethylated allele. Most adult human tumors, including colon, breast, lung, and leukemias, exhibit increased methylation at the P2-4 IGF2 promoters, suggesting further spreading during the neoplastic process. In tumors, this methylation is associated with diminished or absent IGF2 expression from the methylated P3 promoter but maintained expression from P1, an upstream promoter that is not contained within the IGF2 CpG island. Our results demonstrate a remarkable evolution of methylation patterns in the imprinted promoter of the IGF2 gene during aging and carcinogenesis, and provide further evidence for a potential link between aberrant methylation and diseases of aging.
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Affiliation(s)
- J P Issa
- Oncology Center, Johns Hopkins University Medical Institutions, Baltimore, MD 21231, USA
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