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Werner H. The IGF1 Signaling Pathway: From Basic Concepts to Therapeutic Opportunities. Int J Mol Sci 2023; 24:14882. [PMID: 37834331 PMCID: PMC10573540 DOI: 10.3390/ijms241914882] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 10/15/2023] Open
Abstract
Insulin-like growth factor 1 (IGF1) is a peptide growth factor with important functions in multiple aspects of growth, development and metabolism. The biological actions of IGF1 are mediated by the IGF1 receptor (IGF1R), a cell-surface protein that is evolutionarily related to the insulin receptor (InsR). The effects of IGF1 are moderated by a group of binding proteins (IGFBPs) that bind and transport the ligand in the circulation and extracellular fluids. In mechanistic terms, IGF1R function is linked to the MAPK and PI3K signaling pathways. Furthermore, IGF1R has been shown to migrate to cell nucleus, where it functions as a transcriptional activator. The co-localization of IGF1R and MAPK in the nucleus is of major interest as it suggests novel mechanistic paradigms for the IGF1R-MAPK network. Given its potent anti-apoptotic and pro-survival roles, and in view of its almost universal pattern of expression in most types of cancer, IGF1R has emerged as a promising molecular target in oncology. The present review article provides a concise overview of key scientific developments in the research area of IGF and highlights a number of more recent findings, including its nuclear migration and its interaction with oncogenes and tumor suppressors.
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Affiliation(s)
- Haim Werner
- Department of Human Molecular Genetics and Biochemistry, School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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2
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Watt AP, Lefevre C, Wong CS, Nicholas KR, Sharp JA. Insulin regulates human mammosphere development and function. Cell Tissue Res 2021; 384:333-352. [PMID: 33439347 DOI: 10.1007/s00441-020-03360-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 11/19/2020] [Indexed: 11/29/2022]
Abstract
Assessing the role of lactogenic hormones in human mammary gland development is limited due to issues accessing tissue samples and so development of a human in vitro three-dimensional mammosphere model with functions similar to secretory alveoli in the mammary gland can aid to overcome this shortfall. In this study, a mammosphere model has been characterised using human mammary epithelial cells grown on either mouse extracellular matrix or agarose and showed insulin is essential for formation of mammospheres. Insulin was shown to up-regulate extracellular matrix genes. Microarray analysis of these mammospheres revealed an up-regulation of differentiation, cell-cell junctions, and cytoskeleton organisation functions, suggesting mammosphere formation may be regulated through ILK signalling. Comparison of insulin and IGF-1 effects on mammosphere signalling showed that although IGF-1 could induce spherical structures, the cells did not polarise correctly as shown by the absence of up-regulation of polarisation genes and did not induce the expression of milk protein genes. This study demonstrated a major role for insulin in mammary acinar development for secretory differentiation and function indicating the potential for reduced lactational efficiency in women with obesity and gestational diabetes.
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Affiliation(s)
- Ashalyn P Watt
- Institute for Frontier Materials, Deakin University, Geelong, 3216, Australia.
| | - Christophe Lefevre
- Division of Bioinformatics, Walter and Eliza Hall Medical Research Institute, 3000, Melbourne, Australia.,Peter MacCallum Cancer Research Institute, East Melbourne, 3002, Australia
| | - Cynthia S Wong
- Institute for Frontier Materials, Deakin University, Geelong, 3216, Australia
| | - Kevin R Nicholas
- Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Julie A Sharp
- Institute for Frontier Materials, Deakin University, Geelong, 3216, Australia
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3
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Najjar SM, Perdomo G. Hepatic Insulin Clearance: Mechanism and Physiology. Physiology (Bethesda) 2019; 34:198-215. [PMID: 30968756 DOI: 10.1152/physiol.00048.2018] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Upon its secretion from pancreatic β-cells, insulin reaches the liver through the portal circulation to exert its action and eventually undergo clearance in the hepatocytes. In addition to insulin secretion, hepatic insulin clearance regulates the homeostatic level of insulin that is required to reach peripheral insulin target tissues to elicit proper insulin action. Receptor-mediated insulin uptake followed by its degradation constitutes the basic mechanism of insulin clearance. Upon its phosphorylation by the insulin receptor tyrosine kinase, carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) takes part in the insulin-insulin receptor complex to increase the rate of its endocytosis and targeting to the degradation pathways. This review summarizes how this process is regulated and how it is associated with insulin-degrading enzyme in the liver. It also discusses the physiological implications of impaired hepatic insulin clearance: Whereas reduced insulin clearance cooperates with increased insulin secretion to compensate for insulin resistance, it can also cause hepatic insulin resistance. Because chronic hyperinsulinemia stimulates hepatic de novo lipogenesis, impaired insulin clearance also causes hepatic steatosis. Thus impaired insulin clearance can underlie the link between hepatic insulin resistance and hepatic steatosis. Delineating these regulatory pathways should lead to building more effective therapeutic strategies against metabolic syndrome.
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Affiliation(s)
- Sonia M Najjar
- Department of Biomedical Sciences, Ohio University , Athens, Ohio.,Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
| | - Germán Perdomo
- Departamento de Ciencias de la Salud, Universidad de Burgos , Burgos , Spain
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Florian W, Lenfert E, Gerstel D, von Ehrenstein L, Einhoff J, Schmidt G, Logsdon M, Brandner J, Tiegs G, Beauchemin N, Wagener C, Deppert W, Horst AK. CEACAM1 controls the EMT switch in murine mammary carcinoma in vitro and in vivo. Oncotarget 2016; 7:63730-63746. [PMID: 27572314 PMCID: PMC5325399 DOI: 10.18632/oncotarget.11650] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 08/08/2016] [Indexed: 12/29/2022] Open
Abstract
We analyzed the molecular basis for carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1)-controlled inhibition of epithelial-mesenchymal transition (EMT) in a mouse model for mammary adenocarcinoma (WAP-T mice). We demonstrate that silencing of CEACAM1 in WAP-T tumor-derived G-2 cells induces epithelial-mesenchymal plasticity (EMP), as evidenced by typical changes of gene expression, morphology and increased invasion. In contrast, reintroduction of CEACAM1 into G-2 cells reversed up-regulation of genes imposing mesenchymal transition, as well as cellular invasion. We identified the Wnt-pathway as target for CEACAM1-mediated repression of EMT. Importantly, β-catenin phosphorylation status and transcriptional activity strongly depend on CEACAM1 expression: CEACAM1high G-2 cells displayed enhanced phosphorylation of β-catenin at S33/S37/T41 and decreased phosphorylation at Y86, thereby inhibiting canonical Wnt/β-catenin signaling. We identified Src-homology 2 domain-containing phosphatase 2 (SHP-2) as a critical binding partner of CEACAM1 that could modulate β-catenin Y86 phosphorylation. Hence, CEACAM1 serves as a scaffold that controls membrane proximal β-catenin signaling. In vivo, mammary tumors of WAP-T/CEACAM1null mice displayed increased nuclear translocation of β-catenin and a dramatically enhanced metastasis rate compared to WAP-T mice. Hence, CEACAM1 controls EMT in vitro and in vivo by site-specific regulation of β-catenin phosphorylation. Survival analyses of human mammary carcinoma patients corroborated these data, indicating that CEACAM1 is a prognostic marker for breast cancer survival.
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Affiliation(s)
- Wegwitz Florian
- Clinic for General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Georg-August-University of Göttingen, D-37077 Göttingen, Germany
- Institute for Tumor Biology, University Medical Center-Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Eva Lenfert
- Institute for Tumor Biology, University Medical Center-Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Daniela Gerstel
- Center for Diagnostics, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Lena von Ehrenstein
- Institute for Tumor Biology, University Medical Center-Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Julia Einhoff
- Institute for Tumor Biology, University Medical Center-Hamburg-Eppendorf, D-20251 Hamburg, Germany
- Pharmaceutical Institute, Christian-Albrechts-University Kiel, D-24118 Kiel, Germany
| | - Geske Schmidt
- Clinic for General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Georg-August-University of Göttingen, D-37077 Göttingen, Germany
| | - Matthew Logsdon
- Clinic for General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Georg-August-University of Göttingen, D-37077 Göttingen, Germany
| | - Johanna Brandner
- Dermatology and Venerology Department and Clinic, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Gisa Tiegs
- Institute for Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Nicole Beauchemin
- Goodman Cancer Research Centre and Departments of Biochemistry, Medicine and Oncology, McGill University, Montreal, H3G1Y6, Canada
| | - Christoph Wagener
- Center for Diagnostics, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Wolfgang Deppert
- Institute for Tumor Biology, University Medical Center-Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Andrea Kristina Horst
- Institute for Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany
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Lkhagvadorj S, Oh SS, Lee MR, Jung JH, Chung HC, Cha SK, Eom M. Insulin receptor expression in clear cell renal cell carcinoma and its relation to prognosis. Yonsei Med J 2014; 55:861-70. [PMID: 24954312 PMCID: PMC4075388 DOI: 10.3349/ymj.2014.55.4.861] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE Both insulin and insulin-like growth factor (IGF)-1 signaling are key regulators of energy metabolism, cellular growth, proliferation, and survival. The IGF-1 receptor (IGF-1R) is overexpressed in most types of human cancers including renal cell carcinoma (RCC) with poor prognosis. Insulin receptor (IR) shares downstream effectors with IGF-1R; however, the expression and function of IR in the tumorigenesis of renal cancer remains elusive. Therefore, we examined the expression of IR and its prognostic significance in clear cell RCC (CCRCC). MATERIALS AND METHODS Immunohistochemical staining for IR was performed on 126 formalin-fixed paraffin-embedded CCRCC tissue samples. Eight of these cases were utilized for western blot analysis. The results were compared with various clinico-pathologic parameters of CCRCC and patient survival. RESULTS IR was expressed in the nuclei of CCRCC tumor cells in 109 cases (87.9%). Higher IR expression was significantly correlated with the presence of cystic change, lower Fuhrman nuclear grade, lower pathologic T stage, and lower TNM stage, although it wasn't significantly related to diabetes status and patient survival. Western blot analyses supported the results of the immunohistochemistry studies. CONCLUSION IR expression in CCRCC may be associated with favorable prognostic factors.
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Affiliation(s)
- Sayamaa Lkhagvadorj
- Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Sung Soo Oh
- Department of Occupational & Environmental Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Mi-Ra Lee
- Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Jae Hung Jung
- Department of Urology, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Hyun Chul Chung
- Department of Urology, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Seung-Kuy Cha
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, Korea. ; Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Minseob Eom
- Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, Korea.
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6
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The insulin–insulin-like growth-factor receptor family as a therapeutic target in oncology. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Oh MJ, Yi SJ, Kim HS, Kim JH, Jeong YH, van Agthoven T, Jhun BH. Functional roles of BCAR3 in the signaling pathways of insulin leading to DNA synthesis, membrane ruffling and GLUT4 translocation. Biochem Biophys Res Commun 2013; 441:911-6. [PMID: 24216110 DOI: 10.1016/j.bbrc.2013.10.161] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 10/30/2013] [Indexed: 11/28/2022]
Abstract
Breast cancer anti-estrogen resistance 3 (BCAR3) is an SH2-containing signal transducer and is implicated in tumorigenesis of breast cancer cells. In this study, we found that BCAR3 mediates the induction of ERK activation and DNA synthesis by insulin, but not by IGF-1. Specifically, the SH2 domain of BCAR3 is involved in insulin-stimulated DNA synthesis. Differential tyrosine-phosphorylated patterns of the BCAR3 immune complex were detected in insulin and IGF-1 signaling, suggesting that BCAR3 is a distinct target molecule of insulin and IGF-1 signaling. Moreover, microinjection of BCAR3 inhibitory materials inhibited membrane ruffling induced by insulin, while this did not affect insulin-mediated GLUT4 translocation. Taken together, these results demonstrated that BCAR3 plays an important role in the signaling pathways of insulin leading to cell cycle progression and cytoskeleton reorganization, but not GLUT4 translocation.
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Affiliation(s)
- Myung-Ju Oh
- Clinical Trials Management Division, Pharmaceutical Safety Bureau, Ministry of Food and Drug Safety, Cheongwon, Chungbuk 363-700, Republic of Korea
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Abstract
The carcinoembryonic antigen (CEA) family comprises a large number of cellular surface molecules, the CEA-related cell adhesion molecules (CEACAMs), which belong to the Ig superfamily. CEACAMs exhibit a complex expression pattern in normal and malignant tissues. The majority of the CEACAMs are cellular adhesion molecules that are involved in a great variety of distinct cellular processes, for example in the integration of cellular responses through homo- and heterophilic adhesion and interaction with a broad selection of signal regulatory proteins, i.e., integrins or cytoskeletal components and tyrosine kinases. Moreover, expression of CEACAMs affects tumor growth, angiogenesis, cellular differentiation, immune responses, and they serve as receptors for commensal and pathogenic microbes. Recently, new insights into CEACAM structure and function became available, providing further elucidation of their kaleidoscopic functions.
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9
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Effects of somatic mutations in the C-terminus of insulin-like growth factor 1 receptor on activity and signaling. JOURNAL OF SIGNAL TRANSDUCTION 2012; 2012:804801. [PMID: 22778948 PMCID: PMC3384887 DOI: 10.1155/2012/804801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 04/28/2012] [Indexed: 02/03/2023]
Abstract
The insulin-like growth factor I receptor (IGF1R) is overexpressed in several forms of human cancer, and it has emerged as an important target for anticancer drug design. Cancer genome sequencing efforts have recently identified three somatic mutations in IGF1R: A1374V, a deletion of S1278 in the C-terminal tail region of the receptor, and M1255I in the C-terminal lobe of the kinase catalytic domain. The possible effects of these mutations on IGF1R activity and biological function have not previously been tested. Here, we tested the effects of the mutations on the in vitro biochemical activity of IGF1R and on major IGF1R signaling pathways in mammalian cells. While the mutations do not affect the intrinsic tyrosine kinase activity of the receptor, we demonstrate that the basal (unstimulated) levels of MAP kinase and Akt activation are increased in the mutants (relative to wild-type IGF1R). We hypothesize that the enhanced signaling potential of these mutants is due to changes in protein-protein interactions between the IGF1R C-terminus and cellular substrates or modulators.
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Pollak M. The insulin receptor/insulin-like growth factor receptor family as a therapeutic target in oncology. Clin Cancer Res 2012; 18:40-50. [PMID: 22215905 DOI: 10.1158/1078-0432.ccr-11-0998] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Over the past decade, encouraging preclinical and early clinical data concerning the relevance of the insulin receptor/insulin-like growth factor (IGF) receptor family to neoplasia led to ambitious clinical trial programs of more than a dozen drug candidates that target these receptors. These candidates include antireceptor antibodies, antiligand antibodies, receptor-specific tyrosine kinase inhibitors, and agents such as picropodophyllin and metformin that have novel mechanisms of action. Several recently reported phase III clinical trials of anti-IGF-I receptor antibodies have been disappointing and are sufficient to disprove the hypothesis that the antibodies tested have large favorable impacts on unselected patients with cancer. However, many of these trials were designed prior to recent insights concerning pathophysiology and predictive biomarkers. Future studies are required, but it will be important to optimize their design rather than simply repeat the approaches taken to date.
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Affiliation(s)
- Michael Pollak
- Department of Oncology, McGill University, Jewish General Hospital, Montreal, Quebec, Canada.
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11
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Malaguarnera R, Belfiore A. The insulin receptor: a new target for cancer therapy. Front Endocrinol (Lausanne) 2011; 2:93. [PMID: 22654833 PMCID: PMC3356071 DOI: 10.3389/fendo.2011.00093] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 11/19/2011] [Indexed: 12/16/2022] Open
Abstract
A large body of evidences have shown that both the IGF-I receptor (IGF-IR) and the insulin receptor (IR) play a role in cancer development and progression. In particular, IR overactivation by IGF-II is common in cancer cells, especially in dedifferentiated/stem-like cells. In spite of these findings, until very recently, only IGF-IR but not IR has been considered a target in cancer therapy. Although several preclinical studies have showed a good anti-cancer activity of selective anti-IGF-IR drugs, the results of the clinical first trials have been disappointing. In fact, only a small subset of malignant tumors has shown an objective response to these therapies. Development of resistance to anti-IGF-IR drugs may include upregulation of IR isoform A (IR-A) in cancer cells and its overactivation by increased secretion of autocrine IGF-II. These findings have led to the concept that co-targeting IR together with IGF-IR may increase therapy efficacy and prevent adaptive resistance to selective anti-IGF-IR drugs. IR blockade should be especially considered in tumors with high IR-A:IGF-IR ratio and high levels of autocrine IGF-II. Conversely, insulin sensitizers, which ameliorate insulin resistance associated with metabolic disorders and cancer treatments, may have important implications for cancer prevention and management. Only few drugs co-targeting the IR and IGF-IR are currently available. Ideally, future IR targeting strategies should be able to selectively inhibit the tumor promoting effects of IR without impairing its metabolic effects.
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Affiliation(s)
- Roberta Malaguarnera
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University Magna Graecia of CatanzaroCatanzaro, Italy
| | - Antonino Belfiore
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University Magna Graecia of CatanzaroCatanzaro, Italy
- *Correspondence: Antonino Belfiore, Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Catanzaro, Campus Universitario, Viale Europa, località Germaneto, 88100 Catanzaro, Italy. e-mail:
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Belfiore A, Frasca F. IGF and insulin receptor signaling in breast cancer. J Mammary Gland Biol Neoplasia 2008; 13:381-406. [PMID: 19016312 DOI: 10.1007/s10911-008-9099-z] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 10/30/2008] [Indexed: 01/06/2023] Open
Abstract
Major molecular abnormalities in breast cancer include the deregulation of several components of the IGF system. It is well recognized that the epithelial breast cancer cells commonly overexpress the IGF-I receptor while IGF-II is expressed by the tumor stroma. In view to the fact that the IGF-IR has mitogenic, pro-invasive and anti-apoptotic effects and mediates resistance to a variety of anti-cancer therapies, breast cancer is expected to be a candidate to therapeutic approaches aimed to inhibit the IGF-IR. However, there is increasing awareness that IGF system in cancer undergoes signal diversification by various mechanisms. One of these mechanisms is the aberrant expression of insulin receptor (IR) isoform A (IR-A), which is a high affinity receptor for both insulin and IGF-II, in breast cancer cells. Moreover, overexpression of both IGF-IR and IR-A in breast cancer cells, leads to overexpression of hybrid IR/IGF-IR receptors (HRs) as well. Upon binding to IGF-II, both IR-A and HRs may activate unique signaling patterns, which predominantly mediate proliferative effects. A better understanding of IGF system signal diversification in breast cancer has important implications for cancer prevention measures, which should include control of insulin resistance and associated hyperinsulinemia. Moreover, in addition to the IGF-IR, both IR-A and HRs should be also considered as molecular targets for anti-cancer therapies.
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Affiliation(s)
- Antonino Belfiore
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catanzaro, 88100, Catanzaro, Italy,
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Werner H, Weinstein D, Bentov I. Similarities and differences between insulin and IGF-I: structures, receptors, and signalling pathways. Arch Physiol Biochem 2008; 114:17-22. [PMID: 18465355 DOI: 10.1080/13813450801900694] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Insulin and the insulin-like growth factors (IGF-I, IGF-II) are pleiotropic hormones that have multiple roles in regulating vital metabolic and developmental processes. Although most early data suggested that insulin is mainly involved in metabolic activities (e.g. control of sugar levels) and IGF-I/II control growth and differentiation events (e.g. bone elongation, cell division), today, it is clear that there is cross-talk between the various ligands and receptors of the IGF family. As a result of these complex interactions, the spectrum of activities that were classically assigned to insulin or IGF-I/II has greatly expanded, and the signalling events mediated by the insulin and IGF receptors is the subject of intensive research. This review provides a comparative analysis of the structures, receptors, and signalling pathways of insulin and IGF-I.
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Affiliation(s)
- Haim Werner
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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14
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Abstract
Insulin resistance plays a key role in the pathogenesis of several human diseases, including diabetes, obesity, hypertension, and cardiovascular diseases. The predisposition to insulin resistance results from genetic and environmental factors. The search for gene variants that predispose to insulin resistance has been thwarted by its genetically heterogeneous pathogenesis. However, using techniques of targeted mutagenesis and transgenesis in rodents, investigators have developed mouse models to test critical hypotheses on the pathogenesis of insulin resistance. Moreover, experimental crosses among mutant mice have shed light onto the polygenic nature of the interactions underlying this complex metabolic condition.
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Affiliation(s)
- Anindita Nandi
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, NY, USA
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15
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Abstract
Receptor tyrosine kinases of the insulin-insulin-like growth factor (IGF) family promote growth and mediate metabolic signals. Despite their extensive structural homology, genetic evidence indicates that their physiological functions are distinct. Nevertheless, there is limited evidence from cell culture systems suggesting that their signalling capabilities differ. Thus, it remains unclear whether the different physiological roles of insulin and IGF-I receptors result from intrinsic differences in their abilities to activate distinct signalling pathways, or arise from extrinsic differences, such as tissue distribution, relative abundance and developmental regulation.
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Affiliation(s)
- Jane J Kim
- Naomi Berrie Diabetes Center and Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
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16
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Poy MN, Ruch RJ, Fernstrom MA, Okabayashi Y, Najjar SM. Shc and CEACAM1 interact to regulate the mitogenic action of insulin. J Biol Chem 2002; 277:1076-84. [PMID: 11694516 DOI: 10.1074/jbc.m108415200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CEACAM1, a tumor suppressor (previously known as pp120), is a plasma membrane protein that undergoes phosphorylation on Tyr(488) in its cytoplasmic tail by the insulin receptor tyrosine kinase. Co-expression of CEACAM1 with insulin receptors decreased cell growth in response to insulin. Co-immunoprecipitation experiments in intact NIH 3T3 cells and glutathione S-transferase pull-down assays revealed that phosphorylated Tyr(488) in CEACAM1 binds to the SH2 domain of Shc, another substrate of the insulin receptor. Overexpressing Shc SH2 domain relieved endogenous Shc from binding to CEACAM1 and restored MAP kinase activity, growth of cells in response to insulin, and their colonization in soft agar. Thus, by binding to Shc, CEACAM1 sequesters this major coupler of Grb2 to the insulin receptor and down-regulates the Ras/MAP kinase mitogenesis pathway. Additionally, CEACAM1 binding to Shc enhances its ability to compete with IRS-1 for phosphorylation by the insulin receptor. This leads to a decrease in IRS-1 binding to phosphoinositide 3'-kinase and to the down-regulation of the phosphoinositide 3'-kinase/Akt pathway that mediates cell proliferation and survival. Thus, binding to Shc appears to constitute a major mechanism for the down-regulatory effect of CEACAM1 on cell proliferation.
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MESH Headings
- 3T3 Cells
- Adaptor Proteins, Signal Transducing
- Adaptor Proteins, Vesicular Transport
- Animals
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Antigens, Differentiation/genetics
- Antigens, Differentiation/metabolism
- Carcinoembryonic Antigen
- Cell Adhesion Molecules
- Cell Division/physiology
- Cells, Cultured
- Culture Media, Serum-Free
- Down-Regulation/physiology
- Hepatocytes/drug effects
- Hepatocytes/metabolism
- Humans
- Insulin/metabolism
- Insulin/pharmacology
- MAP Kinase Signaling System/physiology
- Male
- Mice
- Mitogens/pharmacology
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphorylation
- Precipitin Tests
- Protein Binding
- Protein Serine-Threonine Kinases
- Proteins/genetics
- Proteins/metabolism
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- Receptor, Insulin/metabolism
- Receptors, Mitogen/metabolism
- Recombinant Fusion Proteins/metabolism
- Shc Signaling Adaptor Proteins
- Src Homology 2 Domain-Containing, Transforming Protein 1
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Affiliation(s)
- Matthew N Poy
- Department of Pharmacology, Medical College of Ohio, Toledo, Ohio 43614, USA
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Kim JJ, Park BC, Kido Y, Accili D. Mitogenic and metabolic effects of type I IGF receptor overexpression in insulin receptor-deficient hepatocytes. Endocrinology 2001; 142:3354-60. [PMID: 11459778 DOI: 10.1210/endo.142.8.8332] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We have previously shown that hepatocytes lacking insulin receptors (Ir-/-) fail to mediate metabolic responses, such as stimulation of glycogen synthesis, while retaining the ability to proliferate in response to IGFs. In this study we have asked whether overexpression of type I IGF receptors would rescue the metabolic response of Ir-/- hepatocytes. After IGF-I stimulation, insulin receptor substrate-1 and -2 phosphorylation and PI3K activity were restored to levels similar to or greater than those seen in wild-type cells. Rates of cell proliferation in response to IGF-I increased approximately 2-fold, whereas glycogen synthesis was restored to wild-type levels, but was comparatively smaller than that elicited by overexpression of insulin receptors. In summary, overexpression of IGF-I receptors in Ir-/- hepatocytes normalized insulin receptor substrate-2 phosphorylation and glycogen synthesis to wild-type levels, whereas it increased cell proliferation above wild-type levels. Moreover, stimulation of glycogen synthesis was submaximal compared with the effect of insulin receptor overexpression. We conclude that IGF-I receptors are more efficiently coupled to cell proliferation than insulin receptors, but are less potent than insulin receptors in stimulating glycogen synthesis. The data are consistent with the possibility that there exist intrinsic signaling differences between insulin and IGF-I receptors.
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Affiliation(s)
- J J Kim
- Naomi Berrie Diabetes Center and Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
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18
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Soni P, Lakkis M, Poy MN, Fernström MA, Najjar SM. The differential effects of pp120 (Ceacam 1) on the mitogenic action of insulin and insulin-like growth factor 1 are regulated by the nonconserved tyrosine 1316 in the insulin receptor. Mol Cell Biol 2000; 20:3896-905. [PMID: 10805733 PMCID: PMC85733 DOI: 10.1128/mcb.20.11.3896-3905.2000] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
pp120 (Ceacam 1) undergoes ligand-stimulated phosphorylation by the insulin receptor, but not by the insulin-like growth factor 1 receptor (IGF-1R). This differential phosphorylation is regulated by the C terminus of the beta-subunit of the insulin receptor, the least conserved domain of the two receptors. In the present studies, deletion and site-directed mutagenesis in stably transfected hepatocytes derived from insulin receptor knockout mice (IR(-/-)) revealed that Tyr(1316), which is replaced by the nonphosphorylatable phenylalanine in IGF-1R, regulated the differential phosphorylation of pp120 by the insulin receptor. Similarly, the nonconserved Tyr(1316) residue also regulated the differential effect of pp120 on IGF-1 and insulin mitogenesis, with pp120 downregulating the growth-promoting action of insulin, but not that of IGF-1. Thus, it appears that pp120 phosphorylation by the insulin receptor is required and sufficient to mediate its downregulatory effect on the mitogenic action of insulin. Furthermore, the current studies revealed that the C terminus of the beta-subunit of the insulin receptor contains elements that suppress the mitogenic action of insulin. Because IR(-/-) hepatocytes are derived from liver, an insulin-targeted tissue, our observations have finally resolved the controversy about the role of the least-conserved domain of insulin and IGF-1Rs in mediating the difference in the mitogenic action of their ligands, with IGF-1 being more mitogenic than insulin.
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Affiliation(s)
- P Soni
- Department of Pharmacology and Therapeutics, Medical College of Ohio, Toledo, Ohio 43614, USA
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19
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Bernier M, Kole HK, Montrose-Rafizadeh C, Kole S. Discrete region of the insulin receptor carboxyl terminus plays key role in insulin action. J Cell Biochem 2000; 78:160-9. [PMID: 10797575 DOI: 10.1002/(sici)1097-4644(20000701)78:1<160::aid-jcb15>3.0.co;2-g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the present study, we attempted to determine the importance of a 23-amino-acid sequence within the carboxyl terminus of the human insulin receptor (IR) molecule in modulating insulin action in Chinese hamster ovary cells. Stable expression of a minigene encoding the receptor fragment led to an increase in insulin-induced IR autophosphorylation that was 2.4-fold higher when compared to that of IR-expressing cells transfected with empty vector. Insulin-stimulated downstream signaling was also significantly elevated in cells expressing the minigene. It was found that expression of the minigene had no effect toward insulin-like growth factor I receptor kinase activity and function. These results indicate that the IR carboxyl terminus contains a motif that acts as a physiologic modulator of insulin signaling. J. Cell. Biochem. 78:160-169, 2000. Published 2000 Wiley-Liss, Inc.
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Affiliation(s)
- M Bernier
- Diabetes Section, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224-2780, USA.
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20
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Soni P, Al-Hosaini KA, Fernström MA, Najjar SM. Cell adhesion properties and effects on receptor-mediated insulin endocytosis are independent properties of pp120, a substrate of the insulin receptor tyrosine kinase. MOLECULAR CELL BIOLOGY RESEARCH COMMUNICATIONS : MCBRC 1999; 1:102-8. [PMID: 10356358 DOI: 10.1006/mcbr.1999.0116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
pp120 undergoes phosphorylation by the tyrosine kinase of the insulin, not the insulin-like growth factor 1 (IGF-1), receptor. Moreover, pp120 stimulates receptor-mediated insulin, but not IGF-1, endocytosis, suggesting that pp120 phosphorylation underlies its effect on insulin endocytosis. pp120 phosphorylation also underlies its bile acid transport and tumor suppression functions. In addition to depending on the intracellular tail, the cell adhesion property of pp120 depends on Arg98 in the N-terminal IgV-like ectoplasmic domain. To investigate whether this domain mediates the effect of pp120 on insulin endocytosis, we mutated Arg98 to Ala and examined whether this mutation altered pp120 phosphorylation and its effect on ligand endocytosis in transfected NIH 3T3 cells. This mutation did not modify either pp120 phosphorylation or its effect on receptor-mediated ligand endocytosis. These findings support the hypothesis that stimulation of insulin endocytosis by pp120 is not mediated by Arg98 in the N-terminal IgV-like ectoplasmic domain of pp120.
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Affiliation(s)
- P Soni
- Department of Pharmacology and Therapeutics, Medical College of Ohio, Toledo 43614-5804, USA
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21
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Modan-Moses D, Janicot M, McLenithan JC, Lane MD, Casella SJ. Expression and function of insulin/insulin-like growth factor I hybrid receptors during differentiation of 3T3-L1 preadipocytes. Biochem J 1998; 333 ( Pt 3):825-31. [PMID: 9677346 PMCID: PMC1219650 DOI: 10.1042/bj3330825] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
During the assembly of cell surface receptors, insulin proreceptors are sometimes joined to insulin-like growth factor (IGF) receptor precursors to form covalently linked hybrid receptors. To address the biological consequences of hybrid receptor formation, we studied 3T3-L1 cells known to undergo a 50-70-fold increase in insulin binding while maintaining nearly constant levels of IGF-I binding during differentiation from preadipocytes into adipocytes. The presence of insulin/IGF receptor hybrids in 3T3-L1 adipocytes was demonstrated by the immunoprecipitation of phosphorylated receptors and a novel enzyme-linked immunoassay. Hybrid receptor levels were very low in the early stages of differentiation and increased rapidly between days 4 and 6, reaching a level about 100-fold higher in the mature adipocyte. Coincident with the hybrid assembly, the formation of archetypal (alpha2,beta2) IGF receptors decreased. In fully differentiated adipocytes, virtually all of the IGF receptors were in hybrid form. Stimulation by IGF-I of receptors isolated from mature adipocytes caused autophosphorylation of IGF receptor beta subunits in hybrid complexes, whereas autophosphorylated IGF holoreceptors were not demonstrable. Insulin and IGF-I were equipotent in stimulating glucose uptake in the differentiated adipocytes, leading to the conclusion that hybrid insulin/IGF receptors can transduce a transmembrane signal when activated by IGF-I. We conclude that hybrid formation constitutes a novel post-translational mechanism whereby increased synthesis of insulin receptors limits the cell surface expression of the homologous IGF receptor. Furthermore, biological actions in 3T3-L1 adipocytes, previously attributed to archetypal IGF receptors, are in fact mediated through hybrid receptors.
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Affiliation(s)
- D Modan-Moses
- Department of Pediatrics Johns Hopkins University School of Medicine, Baltimore, MD 21287-3311, USA
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22
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Najjar SM, Choice CV, Soni P, Whitman CM, Poy MN. Effect of pp120 on receptor-mediated insulin endocytosis is regulated by the juxtamembrane domain of the insulin receptor. J Biol Chem 1998; 273:12923-8. [PMID: 9582324 DOI: 10.1074/jbc.273.21.12923] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
pp120, a substrate of the insulin receptor tyrosine kinase, does not undergo ligand-stimulated phosphorylation by the insulin-like growth factor-1 (IGF-1) receptor. However, replacement of the C-terminal domain of the IGF-1 receptor beta-subunit with the corresponding segment of the insulin receptor restored pp120 phosphorylation by the chimeric receptor. Since pp120 stimulates receptor-mediated insulin endocytosis when it is phosphorylated, we examined whether pp120 regulates IGF-1 receptor endocytosis in transfected NIH 3T3 cells. pp120 failed to alter IGF-1 receptor endocytosis via either wild-type or chimeric IGF-1 receptors. Thus, the effect of pp120 on hormone endocytosis is specific to insulin, and the C-terminal domain of the beta-subunit of the insulin receptor does not regulate the effect of pp120 on insulin endocytosis. Mutation of Tyr960 in the juxtamembrane domain of the insulin receptor abolished the effect of pp120 to stimulate receptor endocytosis, without affecting pp120 phosphorylation by the insulin receptor. These findings suggest that pp120 interacts with two separate domains of the insulin receptor as follows: a C-terminal domain required for pp120 phosphorylation and a juxtamembrane domain required for internalization. We propose that the interaction of pp120 with the juxtamembrane domain is indirect and requires one or more substrates that bind to Tyr960 in the insulin receptor.
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Affiliation(s)
- S M Najjar
- Department of Pharmacology and Therapeutics, Medical College of Ohio, Toledo, Ohio 43614, USA.
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Wang J, Riedel H. Insulin-like growth factor-I receptor and insulin receptor association with a Src homology-2 domain-containing putative adapter. J Biol Chem 1998; 273:3136-9. [PMID: 9452421 DOI: 10.1074/jbc.273.6.3136] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Insulin receptor (IR) and the related insulin-like growth factor-I (IGF-I) receptor (IGF-IR) mediate a variety of metabolic and mitogenic cellular responses, some of which may involve unidentified receptor targets. A Src homology-2 (SH2) domain-coding region of a mouse protein was cloned based on its interaction with IR. It was designated mSH2-B based on its high similarity to an earlier reported rat sequence SH2-B. A role of mSH2-B in IGF-I and insulin action was suggested by the interaction of the SH2 domain with activated IGF-IR and IR catalytic fragments but not with an inactive IR catalytic fragment in the yeast two-hybrid system in vivo and by the hormone-dependent association of a glutathione S-transferase (GST) SH2 domain fusion protein of mSH2-B with both receptors in cell extracts. A comparison of IGF-IR and IR mutants lacking individual Tyr autophosphorylation sites for association with GST mSH2-B showed that homologous juxtamembrane (IR960/IGF-IR950) and C-terminal (IR1322/IGF-IR1316) receptor motifs were required. Synthetic phosphopeptides representing IR960 and IR1322 competed for GST mSH2-B binding to the receptor, suggesting that both motifs participate in the association with mSH2-B. Antibodies raised against GST mSH2-B identified a cellular protein of 92 kDa that was not found to be phosphorylated on Tyr. It co-immunoprecipitated with IGF-IR or IR, which was strictly dependent on receptor activation. IR and IGF-IR Tyr phosphorylation motifs were not identified in the complete SH2-B primary structure, suggesting that it may participate as an adapter rather than a substrate in the IGF-I and insulin signaling pathways.
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Affiliation(s)
- J Wang
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202, USA
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