51
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Ozturk N, Singh I, Mehta A, Braun T, Barreto G. HMGA proteins as modulators of chromatin structure during transcriptional activation. Front Cell Dev Biol 2014; 2:5. [PMID: 25364713 PMCID: PMC4207033 DOI: 10.3389/fcell.2014.00005] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/07/2014] [Indexed: 01/12/2023] Open
Abstract
High mobility group (HMG) proteins are the most abundant non-histone chromatin associated proteins. HMG proteins bind to DNA and nucleosome and alter the structure of chromatin locally and globally. Accessibility to DNA within chromatin is a central factor that affects DNA-dependent nuclear processes, such as transcription, replication, recombination, and repair. HMG proteins associate with different multi-protein complexes to regulate these processes by mediating accessibility to DNA. HMG proteins can be subdivided into three families: HMGA, HMGB, and HMGN. In this review, we will focus on recent advances in understanding the function of HMGA family members, specifically their role in gene transcription regulation during development and cancer.
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Affiliation(s)
- Nihan Ozturk
- LOEWE Research Group Lung Cancer Epigenetic, Max-Planck-Institute for Heart and Lung Research Bad Nauheim, Germany
| | - Indrabahadur Singh
- LOEWE Research Group Lung Cancer Epigenetic, Max-Planck-Institute for Heart and Lung Research Bad Nauheim, Germany
| | - Aditi Mehta
- LOEWE Research Group Lung Cancer Epigenetic, Max-Planck-Institute for Heart and Lung Research Bad Nauheim, Germany
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research Bad Nauheim, Germany
| | - Guillermo Barreto
- LOEWE Research Group Lung Cancer Epigenetic, Max-Planck-Institute for Heart and Lung Research Bad Nauheim, Germany
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52
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Tao D, King JG, Tweedell RE, Jost PJ, Boddey JA, Dinglasan RR. The acute transcriptomic and proteomic response of HC-04 hepatoma cells to hepatocyte growth factor and its implications for Plasmodium falciparum sporozoite invasion. Mol Cell Proteomics 2014; 13:1153-64. [PMID: 24532842 DOI: 10.1074/mcp.m113.035584] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The routine study of human malaria liver-stage biology in vitro is hampered by low infection efficiency of human hepatocellular carcinoma (HCC) lines (<0.1%), poor understanding of steady-state HCC biology, and lack of appropriate tools for trace sample analysis. HC-04 is the only HCC that supports complete development of human malaria parasites. We hypothesized that HCCs are in various intermediate stages of the epithelial-mesenchymal transition (EMT) and HC-04s retain epithelial characteristics that permit infection. We developed a facile analytical approach to test this hypothesis viz. the HC-04 response to hepatocyte growth factor (HGF). We used online two-dimensional liquid chromatography tandem mass spectrometry (2D-LC-MS/MS) to quantify protein expression profiles in HC-04 pre-/post-HGF treatment and validated these results by RT-qPCR and microscopy. We successfully increased protein identification efficiency over offline-2D methods by 12-fold, using less sample material, allowing robust protein quantification. We observed expected up-regulation and down-regulation of EMT protein markers in response to HGF, but also unexpected cellular responses. We also observed that HC-04 is generally more susceptible to HGF-mediated signaling than what was observed for HepG2, a widely used, but poor malaria liver stage-HCC model. Our analytical approach to understanding the basic biology of HC-04 helps us understand the factors that may influence its utility as a model for malaria liver-stage development. We observed that HC-04 treatment with HGF prior to the addition of Plasmodium falciparum sporozoites did not facilitate cell invasion, which suggests unlinking the effect of HGF on malaria liver stage development from hepatocyte invasion. Finally, our 2D-LC-MS/MS approach and broadly applicable experimental strategy should prove useful in the analysis of various hepatocyte-pathogen interactions, tumor progression, and early disease events.
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Affiliation(s)
- Dingyin Tao
- W. Harry Feinstone Department of Molecular Microbiology & Immunology and the Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland 21205, USA
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53
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Klemke M, Müller MH, Wosniok W, Markowski DN, Nimzyk R, Helmke BM, Bullerdiek J. Correlated expression of HMGA2 and PLAG1 in thyroid tumors, uterine leiomyomas and experimental models. PLoS One 2014; 9:e88126. [PMID: 24516594 PMCID: PMC3917869 DOI: 10.1371/journal.pone.0088126] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 01/06/2014] [Indexed: 12/13/2022] Open
Abstract
In pleomorphic adenomas of the salivary glands (PASG) recurrent chromosomal rearrangements affecting either 8q12 or 12q14∼15 lead to an overexpression of the genes of the genuine transcription factor PLAG1 or the architectural transcription factor HMGA2, respectively. Both genes are also affected by recurrent chromosomal rearrangements in benign adipocytic tumors as e. g. lipomas and lipoblastomas. Herein, we observed a strong correlation between the expression of HMGA2 and PLAG1 in 14 benign and 23 malignant thyroid tumors. To address the question if PLAG1 can be activated by HMGA2, the expression of both genes was quantified in 32 uterine leiomyomas 17 of which exhibited an overexpression of HMGA2. All leiomyomas with HMGA2 overexpression also revealed an activation of PLAG1 in the absence of detectable chromosome 8 abnormalities affecting the PLAG1 locus. To further investigate if the overexpression of PLAG1 is inducible by HMGA2 alone, HMGA2 was transiently overexpressed in MCF-7 cells. An increased PLAG1 expression was observed 24 and 48 h after transfection. Likewise, stimulation of HMGA2 by FGF1 in adipose tissue-derived stem cells led to a simultaneous increase of PLAG1 mRNA. Altogether, these data suggest that HMGA2 is an upstream activator of PLAG1. Accordingly, this may explain the formation of tumors as similar as lipomas and lipoblastomas resulting from an activation of either of both genes by chromosomal rearrangements.
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Affiliation(s)
- Markus Klemke
- Center for Human Genetics, University of Bremen, Bremen, Germany
| | | | - Werner Wosniok
- Institute of Statistics, University of Bremen, Bremen, Germany
| | | | - Rolf Nimzyk
- Center for Human Genetics, University of Bremen, Bremen, Germany
| | | | - Jörn Bullerdiek
- Center for Human Genetics, University of Bremen, Bremen, Germany
- Institute for Medical Genetics, University of Rostock, University Medicine, Rostock, Germany
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54
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Cheng SW, Tsai HW, Lin YJ, Cheng PN, Chang YC, Yen CJ, Huang HP, Chuang YP, Chang TT, Lee CT, Chao A, Chou CY, Chan SH, Chow NH, Ho CL. Lin28B is an oncofetal circulating cancer stem cell-like marker associated with recurrence of hepatocellular carcinoma. PLoS One 2013; 8:e80053. [PMID: 24244607 PMCID: PMC3828221 DOI: 10.1371/journal.pone.0080053] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 09/30/2013] [Indexed: 12/21/2022] Open
Abstract
By using an expressed sequence tag bioinformatic algorithm, we identified that Lin28 homolog B (Lin28B) may have an oncofetal expression pattern which may facilitate detecting cancer cells in adults. It is also reported to be a potential marker for cancer stem cells. Therefore, we sought to verify oncofetal-stemness characters of Lin28B and test its potential as a circulating cancer stem cell-like marker in adult HCC patients. Lin28B mRNA was examined in a panel of fetal tissue, adult tissue and tumors. Lin28B was over-expressed or knocked down in HepG2 cells to evaluate its potential as a stem cell-like marker. RT-qPCR for Lin28B was performed in the peripheral blood mononuclear cells from patients with HCC receiving surgery (n=96) and non-HCC controls (n=60) and analyzed its clinical significance. Lin28B showed an oncofetal expression pattern. Its overexpression could upregulate stemness markers (OCT4, Nanog and SOX2) and enhance tumorsphere formation in vitro. Lin28B knockdown had opposite effects. Circulating Lin28B was detected in peripheral blood mononuclear cells in 3 cases (5%) of non-HCC controls and 32 cases (33.3%) of HCC patients. In HCC patients, circulating Lin28B was associated with high tumor grade (P=0.046), large size (P=0.005), high AJCC stage (P=0.044) and BCLC stage (P=0.017). Circulating Lin28B was significantly associated with decreased recurrence-free survival (P<0.001). Circulating Lin28B separated early stage HCC into 2 recurrence-free survival curves (P=0.003). In multivariate analysis, circulating Lin28B was an independent variable associated with early recurrence (P=0.045) and recurrence in early stage HCC (P=0.006). In conclusion, the oncofetal gene Lin28B is a potential oncofetal cancer-stem-cell-like circulating tumor cell marker that correlates with HCC recurrence after hepatectomy. Circulating Lin28B could refine early AJCC stages. Our finding supports the possible use of a TNMC (C for circulating tumor cells) staging system in HCC.
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MESH Headings
- Adult
- Aged
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/mortality
- Carcinoma, Hepatocellular/pathology
- Carcinoma, Hepatocellular/surgery
- Female
- Gene Expression Regulation, Neoplastic
- Hep G2 Cells
- Hepatectomy
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Humans
- Liver Neoplasms/genetics
- Liver Neoplasms/mortality
- Liver Neoplasms/pathology
- Liver Neoplasms/surgery
- Male
- Middle Aged
- Nanog Homeobox Protein
- Neoplasm Recurrence, Local/genetics
- Neoplasm Recurrence, Local/mortality
- Neoplasm Recurrence, Local/pathology
- Neoplasm Recurrence, Local/surgery
- Neoplasm Staging
- Neoplastic Cells, Circulating/metabolism
- Neoplastic Cells, Circulating/pathology
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Octamer Transcription Factor-3/genetics
- Octamer Transcription Factor-3/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- SOXB1 Transcription Factors/genetics
- SOXB1 Transcription Factors/metabolism
- Survival Analysis
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Affiliation(s)
- Shu-Wen Cheng
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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55
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The Lin28b-let-7-Hmga2 axis determines the higher self-renewal potential of fetal haematopoietic stem cells. Nat Cell Biol 2013; 15:916-25. [PMID: 23811688 DOI: 10.1038/ncb2783] [Citation(s) in RCA: 249] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 05/13/2013] [Indexed: 12/14/2022]
Abstract
Mouse haematopoietic stem cells (HSCs) undergo a postnatal transition in several properties, including a marked reduction in their self-renewal activity. We now show that the developmentally timed change in this key function of HSCs is associated with their decreased expression of Lin28b and an accompanying increase in their let-7 microRNA levels. Lentivirus-mediated overexpression of Lin28 in adult HSCs elevates their self-renewal activity in transplanted irradiated hosts, as does overexpression of Hmga2, a well-established let-7 target that is upregulated in fetal HSCs. Conversely, HSCs from fetal Hmga2(-/-) mice do not exhibit the heightened self-renewal activity that is characteristic of wild-type fetal HSCs. Interestingly, overexpression of Hmga2 in adult HSCs does not mimic the ability of elevated Lin28 to activate a fetal lymphoid differentiation program. Thus, Lin28b may act as a master regulator of developmentally timed changes in HSC programs with Hmga2 serving as its specific downstream modulator of HSC self-renewal potential.
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56
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Morishita A, Zaidi MR, Mitoro A, Sankarasharma D, Szabolcs M, Okada Y, D'Armiento J, Chada K. HMGA2 is a driver of tumor metastasis. Cancer Res 2013; 73:4289-99. [PMID: 23722545 DOI: 10.1158/0008-5472.can-12-3848] [Citation(s) in RCA: 206] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The non-histone chromatin-binding protein HMGA2 is expressed predominantly in the mesenchyme before its differentiation, but it is also expressed in tumors of epithelial origin. Ectopic expression of HMGA2 in epithelial cells induces epithelial-mesenchymal transition (EMT), which has been implicated in the acquisition of metastatic characters in tumor cells. However, little is known about in vivo modulation of HMGA2 and its effector functions in tumor metastasis. Here, we report that HMGA2 loss of function in a mouse model of cancer reduces tumor multiplicity. HMGA2-positive cells were identified at the invasive front of human and mouse tumors. In addition, in a mouse allograft model, HMGA2 overexpression converted nonmetastatic 4TO7 breast cancer cells to metastatic cells that homed specifically to liver. Interestingly, expression of HMGA2 enhanced TGFβ signaling by activating expression of the TGFβ type II receptor, which also localized to the invasive front of tumors. Together our results argued that HMGA2 plays a critical role in EMT by activating the TGFβ signaling pathway, thereby inducing invasion and metastasis of human epithelial cancers.
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Affiliation(s)
- Asahiro Morishita
- Departments of Medicine and Pathology, Columbia University College of Physicians & Surgeons, New York, USA
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57
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Li Z, Zhang Y, Ramanujan K, Ma Y, Kirsch DG, Glass DJ. Oncogenic NRAS, required for pathogenesis of embryonic rhabdomyosarcoma, relies upon the HMGA2-IGF2BP2 pathway. Cancer Res 2013; 73:3041-50. [PMID: 23536553 DOI: 10.1158/0008-5472.can-12-3947] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Embryonic rhabdomyosarcoma (ERMS) is the most common soft-tissue tumor in children. Here, we report the identification of the minor groove DNA-binding factor high mobility group AT-hook 2 (HMGA2) as a driver of ERMS development. HMGA2 was highly expressed in normal myoblasts and ERMS cells, where its expression was essential to maintain cell proliferation, survival in vitro, and tumor outgrowth in vivo. Mechanistic investigations revealed that upregulation of the insulin-like growth factor (IGF) mRNA-binding protein IGF2BP2 was critical for HMGA2 action. In particular, IGF2BP2 was essential for mRNA and protein stability of NRAS, a frequently mutated gene in ERMS. shRNA-mediated attenuation of NRAS or pharmacologic inhibition of the MAP-ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) effector pathway showed that NRAS and NRAS-mediated signaling was required for tumor maintenance. Taken together, these findings implicate the HMGA2-IGFBP2-NRAS signaling pathway as a critical oncogenic driver in ERMS.
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Affiliation(s)
- Zhizhong Li
- Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA.
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58
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Fujii Y, Kishi Y, Gotoh Y. IMP2 regulates differentiation potentials of mouse neocortical neural precursor cells. Genes Cells 2013; 18:79-89. [PMID: 23331702 DOI: 10.1111/gtc.12024] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 10/21/2012] [Indexed: 01/02/2023]
Abstract
Neural precursor cells (NPCs) in the mammalian neocortex generate various neuronal and glial cell types in a developmental stage-dependent manner. Most neocortical NPCs lose their neurogenic potential after birth. We have previously shown that high-mobility group A (HMGA) proteins confer the neurogenic potential on early-stage NPCs during the midgestation period, although the underlying mechanisms are not fully understood. In this study, we found that HMGA2 promotes the expression of insulin-like growth factor 2 mRNA-binding protein 2 (IMP2, Igf2bp2) in neocortical NPCs. The level of IMP2 was indeed high in early-stage NPCs compared with that in late-stage NPCs. Importantly, over-expression of IMP2 increased the neurogenic potential and suppressed astrocytic differentiation of late-stage NPCs, whereas knockdown of IMP2 promoted astrocytic differentiation and reduced the neurogenic potential of early-stage neocortical NPCs without overtly affecting cell proliferation. Our results thus identified IMP2 as a developmental stage-dependent regulator of the differentiation potentials of NPCs in the mouse neocortex.
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Affiliation(s)
- Yuki Fujii
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
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59
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Li Z, Gilbert JA, Zhang Y, Zhang M, Qiu Q, Ramanujan K, Shavlakadze T, Eash JK, Scaramozza A, Goddeeris MM, Kirsch DG, Campbell KP, Brack AS, Glass DJ. An HMGA2-IGF2BP2 axis regulates myoblast proliferation and myogenesis. Dev Cell 2012. [PMID: 23177649 DOI: 10.1016/j.devcel.2012.10.019] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A group of genes that are highly and specifically expressed in proliferating skeletal myoblasts during myogenesis was identified. Expression of one of these genes, Hmga2, increases coincident with satellite cell activation, and later its expression significantly declines correlating with fusion of myoblasts into myotubes. Hmga2 knockout mice exhibit impaired muscle development and reduced myoblast proliferation, while overexpression of HMGA2 promotes myoblast growth. This perturbation in proliferation can be explained by the finding that HMGA2 directly regulates the RNA-binding protein IGF2BP2. Add-back of IGF2BP2 rescues the phenotype. IGF2BP2 in turn binds to and controls the translation of a set of mRNAs, including c-myc, Sp1, and Igf1r. These data demonstrate that the HMGA2-IGF2BP2 axis functions as a key regulator of satellite cell activation and therefore skeletal muscle development.
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Affiliation(s)
- Zhizhong Li
- Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
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60
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Barrett LW, Fletcher S, Wilton SD. Regulation of eukaryotic gene expression by the untranslated gene regions and other non-coding elements. Cell Mol Life Sci 2012; 69:3613-34. [PMID: 22538991 PMCID: PMC3474909 DOI: 10.1007/s00018-012-0990-9] [Citation(s) in RCA: 370] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 02/28/2012] [Accepted: 04/02/2012] [Indexed: 02/07/2023]
Abstract
There is now compelling evidence that the complexity of higher organisms correlates with the relative amount of non-coding RNA rather than the number of protein-coding genes. Previously dismissed as "junk DNA", it is the non-coding regions of the genome that are responsible for regulation, facilitating complex temporal and spatial gene expression through the combinatorial effect of numerous mechanisms and interactions working together to fine-tune gene expression. The major regions involved in regulation of a particular gene are the 5' and 3' untranslated regions and introns. In addition, pervasive transcription of complex genomes produces a variety of non-coding transcripts that interact with these regions and contribute to regulation. This review discusses recent insights into the regulatory roles of the untranslated gene regions and non-coding RNAs in the control of complex gene expression, as well as the implications of this in terms of organism complexity and evolution.
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Affiliation(s)
- Lucy W Barrett
- Centre for Neuromuscular and Neurological Disorders (CNND), The University of Western Australia (M518), 35 Stirling Highway, Crawley, WA 6009, Australia.
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61
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Insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs): post-transcriptional drivers of cancer progression? Cell Mol Life Sci 2012; 70:2657-75. [PMID: 23069990 PMCID: PMC3708292 DOI: 10.1007/s00018-012-1186-z] [Citation(s) in RCA: 493] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/28/2012] [Accepted: 10/01/2012] [Indexed: 12/21/2022]
Abstract
The insulin-like growth factor-2 mRNA-binding proteins 1, 2, and 3 (IGF2BP1, IGF2BP2, IGF2BP3) belong to a conserved family of RNA-binding, oncofetal proteins. Several studies have shown that these proteins act in various important aspects of cell function, such as cell polarization, migration, morphology, metabolism, proliferation and differentiation. In this review, we discuss the IGF2BP family’s role in cancer biology and how this correlates with their proposed functions during embryogenesis. IGF2BPs are mainly expressed in the embryo, in contrast with comparatively lower or negotiable levels in adult tissues. IGF2BP1 and IGF2BP3 have been found to be re-expressed in several aggressive cancer types. Control of IGF2BPs’ expression is not well understood; however, let-7 microRNAs, β-catenin (CTNNB1) and MYC have been proposed to be involved in their regulation. In contrast to many other RNA-binding proteins, IGF2BPs are almost exclusively observed in the cytoplasm where they associate with target mRNAs in cytoplasmic ribonucleoprotein complexes (mRNPs). During development, IGF2BPs are required for proper nerve cell migration and morphological development, presumably involving the control of cytoskeletal remodeling and dynamics, respectively. Likewise, IGF2BPs modulate cell polarization, adhesion and migration in tumor-derived cells. Moreover, they are highly associated with cancer metastasis and the expression of oncogenic factors (KRAS, MYC and MDR1). However, a pro-metastatic role of IGF2BPs remains controversial due to the lack of ‘classical’ in vivo studies. Nonetheless, IGF2BPs could provide valuable targets in cancer treatment with many of their in vivo roles to be fully elucidated.
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62
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Hodge JC, Kim TM, Dreyfuss JM, Somasundaram P, Christacos NC, Rousselle M, Quade BJ, Park PJ, Stewart EA, Morton CC. Expression profiling of uterine leiomyomata cytogenetic subgroups reveals distinct signatures in matched myometrium: transcriptional profilingof the t(12;14) and evidence in support of predisposing genetic heterogeneity. Hum Mol Genet 2012; 21:2312-29. [PMID: 22343407 PMCID: PMC3335314 DOI: 10.1093/hmg/dds051] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 01/24/2012] [Accepted: 02/13/2012] [Indexed: 01/22/2023] Open
Abstract
Uterine leiomyomata (UL), the most common neoplasm in reproductive-age women, are classified into distinct genetic subgroups based on recurrent chromosome abnormalities. To develop a molecular signature of UL with t(12;14)(q14-q15;q23-q24), we took advantage of the multiple UL arising as independent clonal lesions within a single uterus. We compared genome-wide expression levels of t(12;14) UL to non-t(12;14) UL from each of nine women in a paired analysis, with each sample weighted for the percentage of t(12;14) cells to adjust for mosaicism with normal cells. This resulted in a transcriptional profile that confirmed HMGA2, known to be overexpressed in t(12;14) UL, as the most significantly altered gene. Pathway analysis of the differentially expressed genes showed significant association with cell proliferation, particularly G1/S checkpoint regulation. This is consistent with the known larger size of t(12;14) UL relative to karyotypically normal UL or to UL in the deletion 7q22 subgroup. Unsupervised hierarchical clustering demonstrated that patient variability is relatively dominant to the distinction of t(12;14) UL compared with non-t(12;14) UL or of t(12;14) UL compared with del(7q) UL. The paired design we employed is therefore important to produce an accurate t(12;14) UL-specific gene list by removing the confounding effects of genotype and environment. Interestingly, myometrium not only clustered away from the tumors, but generally separated based on associated t(12;14) versus del(7q) status. Nine genes were identified whose expression can distinguish the myometrium origin. This suggests an underlying constitutional genetic predisposition to these somatic changes which could potentially lead to improved personalized management and treatment.
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Affiliation(s)
- Jennelle C. Hodge
- Department of Obstetrics, Gynecology and Reproductive Biology and
- Harvard Medical School, Boston, MA02115, USA
- Department of Laboratory Medicine and Pathology and
| | - Tae-Min Kim
- Harvard Medical School, Boston, MA02115, USA
| | | | | | - Nicole C. Christacos
- Department of Obstetrics, Gynecology and Reproductive Biology and
- Harvard Medical School, Boston, MA02115, USA
- Cytogenetics Department, Quest Diagnostics Nichols Institute, Chantilly, VA 20151, USA
| | | | - Bradley J. Quade
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA02115, USA
| | - Peter J. Park
- Harvard Medical School, Boston, MA02115, USA
- Harvard-Partners Center for Genetics and Genomics, Boston, MA 02115, USA
- Children's Hospital Informatics Program, Boston, MA 02115, USA and
| | - Elizabeth A. Stewart
- Department of Obstetrics, Gynecology and Reproductive Biology and
- Harvard Medical School, Boston, MA02115, USA
- Department of Obstetrics and Gynecology, Mayo Clinic, Rochester, MN55905, USA
| | - Cynthia C. Morton
- Department of Obstetrics, Gynecology and Reproductive Biology and
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA02115, USA
- Harvard-Partners Center for Genetics and Genomics, Boston, MA 02115, USA
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63
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Schaeffer V, Hansen KM, Morris DR, LeBoeuf RC, Abrass CK. RNA-binding protein IGF2BP2/IMP2 is required for laminin-β2 mRNA translation and is modulated by glucose concentration. Am J Physiol Renal Physiol 2012; 303:F75-82. [PMID: 22513850 DOI: 10.1152/ajprenal.00185.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Laminin-β2 (LAMB2) is a critical component of the glomerular basement membrane as content of LAMB2 in part determines glomerular barrier permeability. Previously, we reported that high concentrations of glucose reduce expression of this laminin subunit at the translational level. The present studies were undertaken to further define systems that control Lamb2 translation and the effect of high glucose on those systems. Complementary studies were performed using in vitro differentiation of cultured podocytes and mesangial cells exposed to normal and elevated concentrations of glucose, and tissues from control and diabetic rats. Together, these studies provide evidence for regulation of Lamb2 translation by IMP2, an RNA binding protein that targets Lamb2 mRNA to the actin cytoskeleton. Expression of Imp2 itself is regulated by the transcription factor HMGA2, which in turn is regulated by the microRNA let-7b. Elevated concentrations of glucose increase let-7b, which reduces HMGA2 expression, in turn reducing IMP2 and LAMB2. Correlative changes in kidney tissues from control and streptozotocin-induced diabetic rats suggest these control mechanisms are operative in vivo and may contribute to proteinuria in diabetic nephropathy. To our knowledge, this is the first time that translation of Lamb2 mRNA has been linked to the actin cytoskeleton, as well as to specific RNA-binding proteins. These translational control points may provide new targets for therapy in proteinuric disorders such as diabetic nephropathy where LAMB2 levels are reduced.
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Affiliation(s)
- Valerie Schaeffer
- Primary and Specialty Care Medicine, Department of Veterans Affairs Puget Sound Health Care System, Seattle, Washington, USA
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64
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Le HTT, Sorrell AM, Siddle K. Two isoforms of the mRNA binding protein IGF2BP2 are generated by alternative translational initiation. PLoS One 2012; 7:e33140. [PMID: 22427968 PMCID: PMC3299737 DOI: 10.1371/journal.pone.0033140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 02/09/2012] [Indexed: 12/11/2022] Open
Abstract
IGF2BP2 is a member of a family of mRNA binding proteins that, collectively, have been shown to bind to several different mRNAs in mammalian cells, including one of the mRNAs encoding insulin-like growth factor-2. Polymorphisms in the Igf2bp2 gene are associated with risk of developing type 2 diabetes, but detailed functional characterisation of IGF2BP2 protein is lacking. By immunoblotting with C-terminally reactive antibodies we identified a novel IGF2BP2 isoform with a molecular weight of 58 kDa in both human and rodents, that is expressed at somewhat lower levels than the full-length 65 kDa protein. We demonstrated by mutagenesis that this isoform is generated by alternative translation initiation at the internal Met69. It lacks a conserved N-terminal RNA Recognition Motif (RRM) and would be predicted to differ functionally from the canonical full length isoform. We further investigated IGF2BP2 mRNA transcripts by amplification of cDNA using 5'-RACE. We identified multiple transcription start sites of the human, mouse and rat Igf2bp2 genes in a highly conserved region only 50-90 nts upstream of the major translation start site, ruling out the existence of N-terminally extended isoforms. We conclude that structural heterogeneity of IGF2BP2 protein should be taken into account when considering cellular function.
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Affiliation(s)
| | | | - Kenneth Siddle
- University of Cambridge Metabolic Research Laboratories and Department of Clinical Biochemistry, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
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Gorbenko del Blanco D, de Graaff LCG, Posthouwer D, Visser TJ, Hokken-Koelega ACS. Isolated GH deficiency: mutation screening and copy number analysis of HMGA2 and CDK6 genes. Eur J Endocrinol 2011; 165:537-44. [PMID: 21803798 DOI: 10.1530/eje-11-0478] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE In most patients, the genetic cause of isolated GH deficiency (IGHD) is unknown. By identifying several genes associated with height variability within the normal population, three separate genome-wide association studies provided new candidate genes for human growth disorders. We selected two of them for genetic screening of our IGHD population. AIM We aimed to determine whether high-mobility group A2 (HMGA2) and cyclin-dependent protein kinase 6 (CDK6) are involved in the pathogenicity of IGHD. METHODS We directly sequenced coding regions and exon-intron boundaries of the genes HMGA2 and CDK6 in 105 Caucasian IGHD patients from the Dutch HYPOPIT study. In addition, we developed a new probe set of multiplex ligation-dependent probe amplification for both genes in order to detect copy number variations. RESULTS In one patient with classical IGHD phenotype, we identified a new heterozygous 20 bp deletion in the intronic region of HMGA2 (c.250-29_-9del), which was absent in the databases and healthy controls. Together, with recently published data concerning the 12q14 microdeletion syndrome, where patients with an HMGA2 haploinsufficiency had proportionate short stature, this study provides further support of the important role for HMGA2 in growth. In CDK6, we found only known polymorphisms. CONCLUSIONS This study provides the first report of a deletion in the HMGA2 gene that might be related to IGHD. We suggest that this gene is investigated as a second screening in patients with a classical IGHD phenotype in which mutations in classical candidate genes have been excluded.
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Deng LX, Wu GX, Cao Y, Fan B, Gao X, Luo L, Huang N. The chromosomal protein HMGN2 mediates lipopolysaccharide-induced expression of β-defensins in A549 cells. FEBS J 2011; 278:2152-66. [DOI: 10.1111/j.1742-4658.2011.08132.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Winter N, Nimzyk R, Bösche C, Meyer A, Bullerdiek J. Chromatin immunoprecipitation to analyze DNA binding sites of HMGA2. PLoS One 2011; 6:e18837. [PMID: 21533145 PMCID: PMC3077414 DOI: 10.1371/journal.pone.0018837] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 03/21/2011] [Indexed: 12/17/2022] Open
Abstract
Background HMGA2 is an architectonic transcription factor abundantly expressed during embryonic and fetal development and it is associated with the progression of malignant tumors. The protein harbours three basically charged DNA binding domains and an acidic protein binding C-terminal domain. DNA binding induces changes of DNA conformation and hence results in global overall change of gene expression patterns. Recently, using a PCR-based SELEX (Systematic Evolution of Ligands by Exponential Enrichment) procedure two consensus sequences for HMGA2 binding have been identified. Methodology/Principal Findings In this investigation chromatin immunoprecipitation (ChIP) experiments and bioinformatic methods were used to analyze if these binding sequences can be verified on chromatin of living cells as well. Conclusion After quantification of HMGA2 protein in different cell lines the colon cancer derived cell line HCT116 was chosen for further ChIP experiments because of its 3.4-fold higher HMGA2 protein level. 49 DNA fragments were obtained by ChIP. These fragments containing HMGA2 binding sites have been analyzed for their AT-content, location in the human genome and similarities to sequences generated by a SELEX study. The sequences show a significantly higher AT-content than the average of the human genome. The artificially generated SELEX sequences and short BLAST alignments (11 and 12 bp) of the ChIP fragments from living cells show similarities in their organization. The flanking regions are AT-rich, whereas a lower conservation is present in the center of the sequences.
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Affiliation(s)
- Nina Winter
- Centre for Human Genetics, University of Bremen, Bremen, Germany
| | - Rolf Nimzyk
- Centre for Human Genetics, University of Bremen, Bremen, Germany
| | - Carolin Bösche
- Centre for Human Genetics, University of Bremen, Bremen, Germany
| | - Anke Meyer
- Centre for Human Genetics, University of Bremen, Bremen, Germany
| | - Jörn Bullerdiek
- Centre for Human Genetics, University of Bremen, Bremen, Germany
- Clinic for Small Animals and Research Cluster REBIRTH, University of Veterinary Medicine, Hannover, Germany
- * E-mail:
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Hsu CC, Chiang CW, Cheng HC, Chang WT, Chou CY, Tsai HW, Lee CT, Wu ZH, Lee TY, Chao A, Chow NH, Ho CL. Identifying LRRC16B as an oncofetal gene with transforming enhancing capability using a combined bioinformatics and experimental approach. Oncogene 2010; 30:654-67. [PMID: 21102520 DOI: 10.1038/onc.2010.451] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Oncofetal genes are expressed in embryos or fetuses, are downregulated or undetectable in adult tissues, and then re-expressed in tumors. Known oncofetal genes, such as AFP, GCB, FGF18, IMP-1 and SOX1, often have important clinical applications or pivotal biological functions. To find new oncofetal-like genes, we used the public information of expressed sequence tags to systematically analyze gene expression patterns and identified a novel oncofetal-like gene, LRRC16B. It increased the proliferation, anchorage-independent growth and tumorigenesis of transformed cells in xenografts, possibly through its effects on cyclin B1 protein levels. These findings exemplify the feasibility of using bioinformatics to find new oncofetal-like genes and suggest that more genes with important functional roles will be uncovered in the candidate gene list.
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Affiliation(s)
- C-C Hsu
- Institute of Basic Medical Science, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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Abstract
Insulin-like growth factor 2 (IGF-2) mRNA-binding proteins (IMPs) are a family of posttranscriptional regulatory factors with well-understood roles in embryonic development and cancer but with poorly characterized functions in normal adult cells and tissues. We now show that IMP-2, the most ubiquitously expressed member of the family, is abundant in human and mouse adult skeletal myoblasts, where it is indispensable for cell motility and for stabilization of microtubules. To explore the functions of IMP-2, we analyzed the transcripts that were differentially regulated in IMP-2-depleted myoblasts and bound to IMP-2 in normal myoblasts. Among them were the mRNAs of PINCH-2, an important mediator of cell adhesion and motility, and MURF-3, a microtubule-stabilizing protein. By gain- and loss-of-function assays and gel shift experiments, we show that IMP-2 regulates the expression of PINCH-2 and MURF-3 proteins via direct binding to their mRNAs. Upregulation of PINCH-2 in IMP-2-depleted myoblasts is the key event responsible for their decreased motility. Our data reveal how the posttranscriptional regulation of gene expression by IMP-2 contributes to the control of adhesion structures and stable microtubules and demonstrate an important function for IMP-2 in cellular motility.
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Yan YQ, Liu HT, Feng TP, Zhao JZ, Li SL. Clinical pathological significance of HMGA1 and HMGA2 protein expression in esophageal squamous cell carcinoma. Shijie Huaren Xiaohua Zazhi 2010; 18:2869-2873. [DOI: 10.11569/wcjd.v18.i27.2869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To explore the relationship of the protein expression of high mobility group protein AT-hook 1 (HMGA1) and HMGA2 with the development, progression, invasion and metastasis of esophageal squamous cell carcinoma.
METHODS: Sixty-two patients with esophageal squamous cell carcinoma treated at Anyang Tumor Hospital from February 2006 to March 2006 were included in this study. Immunohistochemistry was used to detect the protein expression of HMGA1 and HMGA2 in 62 esophageal squamous cell carcinoma specimens, 31 tumor adjacent atypical hyperplastic epithelial specimens, and 62 normal esophageal epithelial specimens.
RESULTS: The expression of HMGA1 protein was closely correlated with tumor grade, infiltration, lymphatic metastasis and TNM grade in esophageal squamous cell carcinoma (χ2 = 6.649, 6.175, 5.921 and 11.341, respectively; all P < 0.05). The positive rates of HMGA1 protein expression in normal esophageal epithelium, tumor-adjacent atypical hyperplastic epithelium and carcinoma were 8.1% (5/62), 58.1% (18/31) and 69.4% (43/62), respectively, with a significant difference among the three groups (χ2 = 51.429, P < 0.01). The expression of HMGA2 protein was closely correlated with lymphatic metastasis and TNM grade in esophageal squamous cell carcinoma (χ2 = 8.276 and 17.851, respectively; both P < 0.05). The positive rates of HMGA2 protein expression in normal esophageal epithelium, tumor-adjacent atypical hyperplastic epithelium and carcinoma were 71.0% (44/62), 48.4% (15/31) and 4.8% (3/62), respectively, with a significant difference among the three groups (χ2 = 57.621, P < 0.01). There is a positive correlation between the protein expression of HMGA1 and HMGA2 (γp = 0.346, P = 0.006).
CONCLUSION: HMGA1 and HMGA2 play an important role in the carcinogenesis, infiltration and metastasis of esophageal carcinoma. Combined detection of HMGA1 and HMGA2 expression may be used as a molecular parameter for early diagnosis and prognostic evaluation of esophageal squamous cell carcinoma.
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Voight BF, Scott LJ, Steinthorsdottir V, Morris AP, Dina C, Welch RP, Zeggini E, Huth C, Aulchenko YS, Thorleifsson G, McCulloch LJ, Ferreira T, Grallert H, Amin N, Wu G, Willer CJ, Raychaudhuri S, McCarroll SA, Langenberg C, Hofmann OM, Dupuis J, Qi L, Segrè AV, van Hoek M, Navarro P, Ardlie K, Balkau B, Benediktsson R, Bennett AJ, Blagieva R, Boerwinkle E, Bonnycastle LL, Bengtsson Boström K, Bravenboer B, Bumpstead S, Burtt NP, Charpentier G, Chines PS, Cornelis M, Couper DJ, Crawford G, Doney ASF, Elliott KS, Elliott AL, Erdos MR, Fox CS, Franklin CS, Ganser M, Gieger C, Grarup N, Green T, Griffin S, Groves CJ, Guiducci C, Hadjadj S, Hassanali N, Herder C, Isomaa B, Jackson AU, Johnson PRV, Jørgensen T, Kao WHL, Klopp N, Kong A, Kraft P, Kuusisto J, Lauritzen T, Li M, Lieverse A, Lindgren CM, Lyssenko V, Marre M, Meitinger T, Midthjell K, Morken MA, Narisu N, Nilsson P, Owen KR, Payne F, Perry JRB, Petersen AK, Platou C, Proença C, Prokopenko I, Rathmann W, Rayner NW, Robertson NR, Rocheleau G, Roden M, Sampson MJ, Saxena R, Shields BM, Shrader P, Sigurdsson G, Sparsø T, Strassburger K, Stringham HM, Sun Q, Swift AJ, Thorand B, Tichet J, Tuomi T, van Dam RM, van Haeften TW, van Herpt T, van Vliet-Ostaptchouk JV, Walters GB, Weedon MN, Wijmenga C, Witteman J, Bergman RN, Cauchi S, Collins FS, Gloyn AL, Gyllensten U, Hansen T, Hide WA, Hitman GA, Hofman A, Hunter DJ, Hveem K, Laakso M, Mohlke KL, Morris AD, Palmer CNA, Pramstaller PP, Rudan I, Sijbrands E, Stein LD, Tuomilehto J, Uitterlinden A, Walker M, Wareham NJ, Watanabe RM, Abecasis GR, Boehm BO, Campbell H, Daly MJ, Hattersley AT, Hu FB, Meigs JB, Pankow JS, Pedersen O, Wichmann HE, Barroso I, Florez JC, Frayling TM, Groop L, Sladek R, Thorsteinsdottir U, Wilson JF, Illig T, Froguel P, van Duijn CM, Stefansson K, Altshuler D, Boehnke M, McCarthy MI. Twelve type 2 diabetes susceptibility loci identified through large-scale association analysis. Nat Genet 2010; 42:579-89. [PMID: 20581827 DOI: 10.1038/ng.609] [Citation(s) in RCA: 1346] [Impact Index Per Article: 96.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 05/26/2010] [Indexed: 12/11/2022]
Abstract
By combining genome-wide association data from 8,130 individuals with type 2 diabetes (T2D) and 38,987 controls of European descent and following up previously unidentified meta-analysis signals in a further 34,412 cases and 59,925 controls, we identified 12 new T2D association signals with combined P<5x10(-8). These include a second independent signal at the KCNQ1 locus; the first report, to our knowledge, of an X-chromosomal association (near DUSP9); and a further instance of overlap between loci implicated in monogenic and multifactorial forms of diabetes (at HNF1A). The identified loci affect both beta-cell function and insulin action, and, overall, T2D association signals show evidence of enrichment for genes involved in cell cycle regulation. We also show that a high proportion of T2D susceptibility loci harbor independent association signals influencing apparently unrelated complex traits.
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Affiliation(s)
- Benjamin F Voight
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA, USA
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Rodriguez S, Eiriksdottir G, Gaunt TR, Harris TB, Launer LJ, Gudnason V, Day INM. IGF2BP1, IGF2BP2 and IGF2BP3 genotype, haplotype and genetic model studies in metabolic syndrome traits and diabetes. Growth Horm IGF Res 2010; 20:310-318. [PMID: 20627640 PMCID: PMC3268182 DOI: 10.1016/j.ghir.2010.04.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 04/30/2010] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Genetic variation at the insulin-like binding protein 2 (IGF2BP2) gene has been associated with type 2 diabetes (T2D) by genome-wide association studies and by replication analyses. Our aim was to explore the underlying genetic model and mechanism of action, factors accounting for non-replications of the associations, and the effect of variation from pathway-related genes IGF2BP1 and IGF2BP3. METHOD We analysed here the association between T2D (and related traits) and rs4402960 and rs1470579 in IGF2BP2, and rs46522 and rs6949019 (marking IGF2BP1 and IGF2BP3 respectively) from the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study (N approximately 2500 aged 65-96 years). We undertook a retrospective analysis of the deviations from the multiplicative model in previous studies and the present study. RESULTS We replicated an association between rs4402960 and T2D status, and reported significant associations with anthropometric traits, fasting insulin, HOMA-IR and HOMA-%B. These associations were also observed for rs1470579, but not for the SNPs marking IGF2BP1 and IGF2BP3. CONCLUSIONS The lower fasting insulin levels and the impaired beta-cell function associated with IGF2BP2 SNPs are independent of obesity phenotypes. The action of these SNPs on T2D may result from an effect on beta-cell function. This could lead to lower insulin levels, the association with anthropometric traits being secondary. We discuss possible mechanisms of action relating IGF2BP2 with T2D traits. The occurrence of null alleles, the inclusion of T2D patients in analyses of metabolic syndrome risk traits and the genetic model, are possible factors accounting for non-replications of IGF2BP2 associations with T2D.
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Affiliation(s)
- S Rodriguez
- Department of Social Medicine, University of Bristol, Bristol, United Kingdom.
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Ying S, Kojima T, Kawada A, Nachat R, Serre G, Simon M, Takahara H. An intronic enhancer driven by NF-κB contributes to transcriptional regulation of peptidylarginine deiminase type I gene in human keratinocytes. J Invest Dermatol 2010; 130:2543-52. [PMID: 20596086 DOI: 10.1038/jid.2010.179] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Peptidylarginine deiminases (PADs) catalyze the conversion of protein-bound arginine to citrulline residues. In human epidermis, where filaggrin is the main deiminated protein, three PADs are detected with specific patterns of expression depending on the keratinocyte (KC) differentiation state. Previous characterizations of the PAD-encoding gene promoters have shown that proximal regulation alone is not sufficient to explain this specificity of expression. In this work, we describe an evolutionarily highly conserved nucleotide segment located in the first intron of the PAD1 gene (PADI1). Luciferase reporter assays showed that it enhances the activity of the PADI1 promoter, in a calcium- and orientation-independent manner. Mutation of a putative NF-κB cis-element markedly reduced its enhancer activity, which also confirmed its potential regulatory function. Chromatin immunoprecipitation assays evidenced the binding of both p65 and p50 NF-κB subunits to the cis-element, and RNA interference inhibition assays confirmed that NF-κB contributes to the PADI1 transcriptional control. Furthermore, the intronic enhancer and promoter of PADI1 potentially interact through chromatin looping, as indicated by chromosome conformation capture assays. Our findings provide evidence that an NF-κB-mediated signaling pathway is involved in PADI1 regulation in human epidermal KCs.
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Affiliation(s)
- Shibo Ying
- Department of Applied Life Sciences, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
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Identification of target genes for wild type and truncated HMGA2 in mesenchymal stem-like cells. BMC Cancer 2010; 10:329. [PMID: 20576167 PMCID: PMC2912264 DOI: 10.1186/1471-2407-10-329] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 06/25/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The HMGA2 gene, coding for an architectural transcription factor involved in mesenchymal embryogenesis, is frequently deranged by translocation and/or amplification in mesenchymal tumours, generally leading to over-expression of shortened transcripts and a truncated protein. METHODS To identify pathways that are affected by sarcoma-associated variants of HMGA2, we have over-expressed wild type and truncated HMGA2 protein in an immortalized mesenchymal stem-like cell (MSC) line, and investigated the localisation of these proteins and their effects on differentiation and gene expression patterns. RESULTS Over-expression of both transgenes blocked adipogenic differentiation of these cells, and microarray analysis revealed clear changes in gene expression patterns, more pronounced for the truncated protein. Most of the genes that showed altered expression in the HMGA2-overexpressing cells fell into the group of NF-kappaB-target genes, suggesting a central role for HMGA2 in this pathway. Of particular interest was the pronounced up-regulation of SSX1, already implicated in mesenchymal oncogenesis and stem cell functions, only in cells expressing the truncated protein. Furthermore, over-expression of both HMGA2 forms was associated with a strong repression of the epithelial marker CD24, consistent with the reported low level of CD24 in cancer stem cells. CONCLUSIONS We conclude that the c-terminal part of HMGA2 has important functions at least in mesenchymal cells, and the changes in gene expression resulting from overexpressing a protein lacking this domain may add to the malignant potential of sarcomas.
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Skalniak L, Mizgalska D, Zarebski A, Wyrzykowska P, Koj A, Jura J. Regulatory feedback loop between NF-kappaB and MCP-1-induced protein 1 RNase. FEBS J 2009; 276:5892-905. [PMID: 19747262 DOI: 10.1111/j.1742-4658.2009.07273.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A novel gene ZC3H12A, encoding MCP-1-induced protein 1 (MCPIP), was recently identified in human peripheral blood monocytes treated with monocyte chemotactic protein 1 (MCP-1) and in human monocyte-derived macrophages stimulated with interleukin (IL)-1beta. These experiments revealed that the gene undergoes rapid and potent transcription induction upon stimulation with proinflammatory molecules, such as MCP-1, IL-1beta, tumour necrosis factor alpha and lipopolysaccharide. Here we show that the induction of ZC3H12A by IL-1beta is predominantly NF-kappaB-dependent because inhibition of this signalling pathway results in the impairment of ZC3H12A transcription activation. Our results indicate the presence of an IL-1beta-responding region within the second intron of the ZC3H12A gene, which contains four functional NF-kappaB-binding sites. Therefore, we propose that this transcription enhancer transduces a ZC3H12A transcription-inducing signal after IL-1beta stimulation. Recent reports suggest that MCPIP acts as a negative regulator of inflammatory processes because it is engaged in the degradation of transcripts coding for certain proinflammatory cytokines. Our observations provide evidence for a novel negative feedback loop in the activation of NF-kappaB and point to potential significance of MCPIP in the treatment of various pathological states, such as diabetes or cancer that involve disturbances in the functioning of the NF-kappaB system.
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Affiliation(s)
- Lukasz Skalniak
- Department of Cell Biochemistry, Faculty of Biochemistry, Jagiellonian University, Krakow, Poland
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76
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HMGA1 levels influence mitochondrial function and mitochondrial DNA repair efficiency. Mol Cell Biol 2009; 29:5426-40. [PMID: 19687300 DOI: 10.1128/mcb.00105-09] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
HMGA chromatin proteins, a family of gene regulatory factors found at only low concentrations in normal cells, are almost universally overexpressed in cancer cells. HMGA proteins are located in the nuclei of normal cells except during the late S/G(2) phases of the cell cycle, when HMGA1, one of the members of the family, reversibly migrates to the mitochondria, where it binds to mitochondrial DNA (mtDNA). In many cancer cells, this controlled shuttling is lost and HMGA1 is found in mitochondria throughout the cell cycle. To investigate the effects of HMGA1 on mitochondria, we employed a genetically engineered line of human MCF-7 cells in which the levels of transgenic HMGA1 protein could be reversibly controlled. "Turn-ON" and "turn-OFF" time course experiments were performed with these cells to either increase or decrease intracellular HMGA1 levels, and various mitochondrial changes were monitored. Results demonstrated that changes in both mtDNA levels and mitochondrial mass inversely paralleled changes in HMGA1 concentrations, strongly implicating HMGA1 in the regulation of these parameters. Additionally, the level of cellular reactive oxygen species (ROS) increased and the efficiency of repair of oxidatively damaged mtDNA decreased as consequences of elevated HMGA1 expression. Increased ROS levels and reduced repair efficiency in HMGA1-overexpressing cells likely contribute to the increased occurrence of mutations in mtDNA frequently observed in cancer cells.
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77
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Peter ME. Let-7 and miR-200 microRNAs: guardians against pluripotency and cancer progression. Cell Cycle 2009; 8:843-52. [PMID: 19221491 DOI: 10.4161/cc.8.6.7907] [Citation(s) in RCA: 338] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Micro (mi)RNAs are emerging as important regulators of cellular differentiation, their importance underscored by the fact that they are often dysregulated during carcinogenesis. Two evolutionary conserved families, let-7 and miR-200, regulate key differentiation processes during development. Loss of let-7 in cancer results in reverse embryogenesis and dedifferentiation, and miR-200 has been identified as a powerful regulator of epithelial-to-mesenchymal transition (EMT). Recent findings have connected let-7 with stem cell maintenance and point at a connection between EMT and stem cell formation. A part of tumor progression can be viewed as a continuum of progressive dedifferentiation (EMT) with a cell at the endpoint that has stem cell-like properties. I propose that steps of this process are driven by specific changes in the expression of let-7 and miR-200 family members.
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Affiliation(s)
- Marcus E Peter
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, Illinois 60637, USA.
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Srivastava V, Deshpande SN, Nimgaonkar VL, Lerer B, Thelma BK. Genetic correlates of olanzapine-induced weight gain in schizophrenia subjects from north India: role of metabolic pathway genes. Pharmacogenomics 2008; 9:1055-68. [DOI: 10.2217/14622416.9.8.1055] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: Olanzapine is an efficacious drug often used as a first-line medication in the treatment for schizophrenia. However, weight gain is a notable adverse drug reaction of this medication in a proportion of patients and a major cause of noncompliance. Several hypotheses, including a contribution from hormonal, physiological and environmental factors, have been postulated. In this study, we aimed to analyze a possible association of genetic polymorphisms at four important candidate genes involved in appetite regulation and antipsychotic-induced metabolic syndrome with olanzapine-induced weight gain. Materials & methods: A total of 154 schizophrenia subjects were recruited in a systematic, 6-week, open-label trial of olanzapine. We investigated the contribution of 14 polymorphisms from four genes, namely, leptin, lipoprotein lipase, tri-acyl-glycerol lipase and citrate lyase using a binary logistic regression analysis towards olanzapine-induced weight gain. Results: rs 4731426 C/G SNP, a variant in the leptin gene, was moderately associated with median weight gain (Δ weightm; [p = 0.05; OR: 2.2; 95% CI: 0.99–4.90]) and significantly associated with extreme weight gain (Δ weighte [p = 0.019; OR: 11.43; 95% CI: 1.49–87.55]) when average drug dose was included in a regression model. Using in silico analysis, we found that this associated intronic SNP in the leptin gene alters the binding of zinc finger 5, a transcription factor. Conclusion: The leptin gene may be a promising candidate for olanzapine-induced weight gain. As the associations are modest, replicate studies are warranted. This approach may facilitate rationalized drug regimens.
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Affiliation(s)
- Vibhuti Srivastava
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India
| | | | - Vishwajit L Nimgaonkar
- Department of Psychaitry, School of Medicine and Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, PA 15213, USA
| | - Bernard Lerer
- Department of Psychaitry, Hadassah-Hebrew University Medical Center, Ein Karem, Jerusalem, Israel
| | - BK Thelma
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India
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Borecki IB, Province MA. Linkage and Association: Basic Concepts. GENETIC DISSECTION OF COMPLEX TRAITS 2008; 60:51-74. [DOI: 10.1016/s0065-2660(07)00403-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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