1
|
Galal MA, Alouch SS, Alsultan BS, Dahman H, Alyabis NA, Alammar SA, Aljada A. Insulin Receptor Isoforms and Insulin Growth Factor-like Receptors: Implications in Cell Signaling, Carcinogenesis, and Chemoresistance. Int J Mol Sci 2023; 24:15006. [PMID: 37834454 PMCID: PMC10573852 DOI: 10.3390/ijms241915006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/22/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
This comprehensive review thoroughly explores the intricate involvement of insulin receptor (IR) isoforms and insulin-like growth factor receptors (IGFRs) in the context of the insulin and insulin-like growth factor (IGF) signaling (IIS) pathway. This elaborate system encompasses ligands, receptors, and binding proteins, giving rise to a wide array of functions, including aspects such as carcinogenesis and chemoresistance. Detailed genetic analysis of IR and IGFR structures highlights their distinct isoforms, which arise from alternative splicing and exhibit diverse affinities for ligands. Notably, the overexpression of the IR-A isoform is linked to cancer stemness, tumor development, and resistance to targeted therapies. Similarly, elevated IGFR expression accelerates tumor progression and fosters chemoresistance. The review underscores the intricate interplay between IRs and IGFRs, contributing to resistance against anti-IGFR drugs. Consequently, the dual targeting of both receptors could present a more effective strategy for surmounting chemoresistance. To conclude, this review brings to light the pivotal roles played by IRs and IGFRs in cellular signaling, carcinogenesis, and therapy resistance. By precisely modulating these receptors and their complex signaling pathways, the potential emerges for developing enhanced anti-cancer interventions, ultimately leading to improved patient outcomes.
Collapse
Affiliation(s)
- Mariam Ahmed Galal
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
- Department of Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol BS8 1QU, UK
| | - Samhar Samer Alouch
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Buthainah Saad Alsultan
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Huda Dahman
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Nouf Abdullah Alyabis
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Sarah Ammar Alammar
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Ahmad Aljada
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| |
Collapse
|
2
|
Yan L, Shen Z, Lu Z. Increases in the expression of Na + /H + exchanger 1 and 3 are associated with insulin signalling in the ruminal epithelium. J Anim Physiol Anim Nutr (Berl) 2017; 102:e569-e577. [PMID: 29027700 DOI: 10.1111/jpn.12798] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 07/10/2017] [Indexed: 12/16/2022]
Abstract
Na+ /H+ exchanger (NHE), which catalyses the exchange of extracellular Na+ for intracellular H+ , is of importance in the maintenance of Na+ and pH homoeostasis for rumen epithelial cells. Studies in ruminants showed that high concentrate diets could increase the expression of NHE in ruminal epithelium. Results of recent studies further indicated that insulin, as an important hormone closely related to dietary concentrate, could enhance the expression of NHE. In this study, we have investigated the mechanisms of insulin regulating the expression of NHE in rumen epithelial cells and its potential role in dietary modulation of NHE expression in ruminal epithelium of cows. In primary culture, insulin increased phosphorylation of ERK 1/2 and AKT in rumen epithelial cells. However, this promotion was diminished by insulin receptor inhibitor. Insulin also stimulated NHE1 and NHE3 expression. But this increase was suppressed by insulin receptor inhibitor, ERK inhibitor and AKT inhibitor. In the present animal experiment, NHE1 and NHE3 expression increased in rumen epithelium of cows ingesting a high concentrate diet (HC, 60% concentrate), accompanied by increased insulin concentration in plasma, compared to those feeding a low concentrate diet (LC, 20% concentrate). Furthermore, the phosphorylation of ERK1/2 and AKT was higher in the rumen epithelium of the HC group than those in the LC group. Collectively, these results indicate that diet-dependent change of NHE1 and NHE3 abundance was mediated, at least in part, by plasma insulin through the ERK and AKT pathway.
Collapse
Affiliation(s)
- L Yan
- Lab of Animal Physiology and Biochemistry, Nanjing Agriculture University, Nanjing, China.,Dairy Herd Improvement Center, Henan Province Bureau of Animal Husbandry, Zhengzhou, China
| | - Z Shen
- Lab of Animal Physiology and Biochemistry, Nanjing Agriculture University, Nanjing, China
| | - Z Lu
- Lab of Animal Physiology and Biochemistry, Nanjing Agriculture University, Nanjing, China
| |
Collapse
|
3
|
Belfiore A, Malaguarnera R, Vella V, Lawrence MC, Sciacca L, Frasca F, Morrione A, Vigneri R. Insulin Receptor Isoforms in Physiology and Disease: An Updated View. Endocr Rev 2017; 38:379-431. [PMID: 28973479 PMCID: PMC5629070 DOI: 10.1210/er.2017-00073] [Citation(s) in RCA: 234] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/13/2017] [Indexed: 02/08/2023]
Abstract
The insulin receptor (IR) gene undergoes differential splicing that generates two IR isoforms, IR-A and IR-B. The physiological roles of IR isoforms are incompletely understood and appear to be determined by their different binding affinities for insulin-like growth factors (IGFs), particularly for IGF-2. Predominant roles of IR-A in prenatal growth and development and of IR-B in metabolic regulation are well established. However, emerging evidence indicates that the differential expression of IR isoforms may also help explain the diversification of insulin and IGF signaling and actions in various organs and tissues by involving not only different ligand-binding affinities but also different membrane partitioning and trafficking and possibly different abilities to interact with a variety of molecular partners. Of note, dysregulation of the IR-A/IR-B ratio is associated with insulin resistance, aging, and increased proliferative activity of normal and neoplastic tissues and appears to sustain detrimental effects. This review discusses novel information that has generated remarkable progress in our understanding of the physiology of IR isoforms and their role in disease. We also focus on novel IR ligands and modulators that should now be considered as an important strategy for better and safer treatment of diabetes and cancer and possibly other IR-related diseases.
Collapse
Affiliation(s)
- Antonino Belfiore
- Endocrinology, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy
| | - Roberta Malaguarnera
- Endocrinology, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy
| | - Veronica Vella
- School of Human and Social Sciences, University Kore of Enna, via della Cooperazione, 94100 Enna, Italy
| | - Michael C. Lawrence
- Structural Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Laura Sciacca
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95122 Catania, Italy
| | - Francesco Frasca
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95122 Catania, Italy
| | - Andrea Morrione
- Department of Urology and Biology of Prostate Cancer Program, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Riccardo Vigneri
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95122 Catania, Italy
| |
Collapse
|
4
|
Kharrazian D, Herbert M, Vojdani A. Detection of Islet Cell Immune Reactivity with Low Glycemic Index Foods: Is This a Concern for Type 1 Diabetes? J Diabetes Res 2017; 2017:4124967. [PMID: 28819632 PMCID: PMC5551512 DOI: 10.1155/2017/4124967] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 04/25/2017] [Accepted: 05/17/2017] [Indexed: 12/11/2022] Open
Abstract
Dietary management of autoimmune diabetes includes low glycemic foods classified from the glycemic index, but it does not consider the role that immunoreactive foods may play with the immunological etiology of the disease. We measured the reactivity of either monoclonal or polyclonal affinity-purified antibodies to insulin, insulin receptor alpha, insulin receptor beta, zinc transporter 8 (ZnT8), tyrosine phosphatase-based islet antigen 2 (IA2), and glutamic acid decarboxylase (GAD) 65 and 67 against 204 dietary proteins that are commonly consumed. Dietary protein determinants included unmodified (raw) and modified (cooked and roasted) foods, herbs, spices, food gums, brewed beverages, and additives. There was no immune reactivity between insulin or insulin receptor beta and dietary proteins. However, we identified strong to moderate immunological reactivity with antibodies against insulin receptor alpha, ZnT8, IA2, GAD-65, and GAD-67 with several dietary proteins. We also identified 49 dietary proteins found in foods classified as low glycemic foods with immune reactivity to autoimmune target sites. Laboratory analysis of immunological cross-reactivity between pancreas target sites and dietary proteins is the initial step necessary in determining whether dietary proteins may play a potential immunoreactive role in autoimmune diabetes.
Collapse
Affiliation(s)
- Datis Kharrazian
- Harvard Medical School, Boston, MA, USA
- TRANSCEND Research, Department of Neurology, Massachusetts General Hospital, Charlestown, Boston, MA 02129, USA
- Department of Preventive Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Martha Herbert
- Harvard Medical School, Boston, MA, USA
- TRANSCEND Research, Department of Neurology, Massachusetts General Hospital, Charlestown, Boston, MA 02129, USA
| | - Aristo Vojdani
- Department of Preventive Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA
- Immunosciences Laboratory, Inc., Los Angeles, CA, USA
| |
Collapse
|
5
|
van Beijnum JR, Pieters W, Nowak-Sliwinska P, Griffioen AW. Insulin-like growth factor axis targeting in cancer and tumour angiogenesis - the missing link. Biol Rev Camb Philos Soc 2016; 92:1755-1768. [PMID: 27779364 DOI: 10.1111/brv.12306] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 09/15/2016] [Accepted: 09/21/2016] [Indexed: 12/14/2022]
Abstract
Numerous molecular players in the process of tumour angiogenesis have been shown to offer potential for therapeutic targeting. Initially denoted to be involved in malignant transformation and tumour progression, the insulin-like growth factor (IGF) signalling axis has been subject to therapeutic interference, albeit with limited clinical success. More recently, IGFs and their receptors have received attention for their contribution to tumour angiogenesis, which offers novel therapeutic opportunities. Here we review the contribution of this signalling axis to tumour angiogenesis, the mechanisms of resistance to therapy and the interplay with other pro-angiogenic pathways, to offer insight in the renewed interest in the application of IGF axis targeting agents in anti-cancer combination therapies.
Collapse
Affiliation(s)
- Judy R van Beijnum
- Department of Medical Oncology, Angiogenesis Laboratory, VU University Medical Center, PO box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Wietske Pieters
- Department of Medical Oncology, Angiogenesis Laboratory, VU University Medical Center, PO box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Patrycja Nowak-Sliwinska
- School of Pharmaceutical Sciences, University of Geneva (UNIGE), Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
| | - Arjan W Griffioen
- Department of Medical Oncology, Angiogenesis Laboratory, VU University Medical Center, PO box 7057, 1007 MB, Amsterdam, The Netherlands
| |
Collapse
|
6
|
Perks CM, Zielinska HA, Wang J, Jarrett C, Frankow A, Ladomery MR, Bahl A, Rhodes A, Oxley J, Holly JMP. Insulin Receptor Isoform Variations in Prostate Cancer Cells. Front Endocrinol (Lausanne) 2016; 7:132. [PMID: 27733843 PMCID: PMC5039983 DOI: 10.3389/fendo.2016.00132] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 09/08/2016] [Indexed: 01/10/2023] Open
Abstract
Men who develop prostate cancer (PCa) increasingly have one of the co-morbidities associated with a Western lifestyle that are characterized by hyperinsulinemia, hyperglycemia and increased expression of insulin-like growth factors-I (IGF-I) and IGF-II. Each have been associated with poor prognosis and more aggressive cancers that exhibit increased metabolism and increased glucose uptake. The insulin receptor (IR) has two splice isoforms IR-A and IR-B: IR-A has a higher affinity for IGF-II comparable to that for insulin, whereas the IR-B isoform predominantly just binds to insulin. In this study, we assessed alterations in the IR-A and IR-B isoform ratio and associated changes in cell proliferation and migration of PCa cell lines following exposure to altered concentrations of glucose and treatment with IGF-II and insulin. We observed that where IR-B predominated insulin had a greater effect on migration than IGF-II and IGF-II was more effective when IR-A was the main isoform. With regard to proliferation IGF-II was more effective than insulin regardless of which isoform was dominant. We assessed the abundance of the IR isoforms both in vivo and in vitro and observed that the majority of the tissue samples and cell lines expressed more IR-A than IR-B. Alterations in the isoforms in response to changes in their hormonal milieu could have a profound impact on how malignant cells behave and play a role in promoting carcinogenesis. A greater understanding of the mechanisms underlying changes in alternative splicing of the IR may provide additional targets for future cancer therapies.
Collapse
Affiliation(s)
- Claire M. Perks
- IGFs and Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK
| | - H. A. Zielinska
- IGFs and Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK
| | - Jing Wang
- IGFs and Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK
| | - Caroline Jarrett
- IGFs and Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK
| | - A. Frankow
- IGFs and Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK
| | - Michael R. Ladomery
- Department of Biological, Biomedical and Analytical Sciences, Faculty of Health and Applied Sciences, University of the West of England, Bristol, UK
| | - Amit Bahl
- Department of Clinical Oncology, Bristol Haematology and Oncology Centre, University Hospitals Bristol, Bristol, UK
| | - Anthony Rhodes
- Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jon Oxley
- Department of Cellular Histopathology, North Bristol NHS Trust, Bristol, UK
| | - Jeff M. P. Holly
- IGFs and Metabolic Endocrinology Group, School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK
| |
Collapse
|
7
|
Screening and biological evaluation of myricetin as a multiple target inhibitor insulin, epidermal growth factor, and androgen receptor; in silico and in vitro. Invest New Drugs 2015; 33:575-93. [PMID: 25895100 DOI: 10.1007/s10637-015-0240-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Accepted: 04/07/2015] [Indexed: 01/04/2023]
Abstract
Myricetin is a naturally omnipresent benzo-α-pyrone flavonoids derivative; has potent anticancer activity. Receptor tyrosine kinases family provides the decisive role in cancer initiation and progression. These receptors have recently caught the attention of the researchers as an attractive target to combat cancer, owing to the evidences endorsed their over-expression on cancer cells. This study is a concerted effort to explore the potent and specific multi-targeted inhibitor against RTKs and AR\ER employing molecular docking approach. IR, IGF1R, EGFR, VEGFR1, VEGFR2, and AR\ER were chosen as a protein and natural compounds as a ligand. Molecular docking procedure followed by using Maestro 9.6 (Schrödinger Inc). All natural compounds were docked with the X-ray crystal structures of selected proteins by employing grid-based ligand docking with energetics Maestro 9.6. IBS natural compounds docked with each selected protein molecules by using GLIDE high throughput virtual screening. On the basis of Gscore, we selected 20 compounds from IBS (50,000 compounds) along with 68 anticancer compounds from published literature for GLIDE extra precision molecular docking. Calculated docking free energy yielded the excellent dock score for the myricetin when docked with proteins EGFR, IR, and AR\ER. Protein-ligand interactions profile highlighted that the lipophilic, hydrogen bonding and π-π stacking interactions play a central role in protein-ligand interactions at the active site. The results of MTT assay reveal that the myricetin inhibit the viability and proliferation of cancer cells in a dose-dependent manner. Treatment with the myricetin led to down-regulation of mRNA expression of EGFR, IR, mTOR, and Bcl-2. Although, further in vitro and in vivo experimental studies are required for the experimental validation of our findings.
Collapse
|
8
|
Lu ZX, Huang Q, Park JW, Shen S, Lin L, Tokheim CJ, Henry MD, Xing Y. Transcriptome-wide landscape of pre-mRNA alternative splicing associated with metastatic colonization. Mol Cancer Res 2015; 13:305-18. [PMID: 25274489 PMCID: PMC4336826 DOI: 10.1158/1541-7786.mcr-14-0366] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED Metastatic colonization is an ominous feature of cancer progression. Recent studies have established the importance of pre-mRNA alternative splicing (AS) in cancer biology. However, little is known about the transcriptome-wide landscape of AS associated with metastatic colonization. Both in vitro and in vivo models of metastatic colonization were utilized to study AS regulation associated with cancer metastasis. Transcriptome profiling of prostate cancer cells and derivatives crossing in vitro or in vivo barriers of metastasis revealed splicing factors with significant gene expression changes associated with metastatic colonization. These include splicing factors known to be differentially regulated in epithelial-mesenchymal transition (ESRP1, ESRP2, and RBFOX2), a cellular process critical for cancer metastasis, as well as novel findings (NOVA1 and MBNL3). Finally, RNA-seq indicated a large network of AS events regulated by multiple splicing factors with altered gene expression or protein activity. These AS events are enriched for pathways important for cell motility and signaling, and affect key regulators of the invasive phenotype such as CD44 and GRHL1. IMPLICATIONS Transcriptome-wide remodeling of AS is an integral regulatory process underlying metastatic colonization, and AS events affect the metastatic behavior of cancer cells.
Collapse
Affiliation(s)
- Zhi-xiang Lu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Qin Huang
- Department of Molecular Physiology and Biophysics, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa. Department of Pathology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa
| | - Juw Won Park
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Shihao Shen
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Lan Lin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Collin J Tokheim
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Michael D Henry
- Department of Molecular Physiology and Biophysics, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa. Department of Pathology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa.
| | - Yi Xing
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California.
| |
Collapse
|
9
|
Lin JC, Tarn WY, Hsieh WK. Emerging role for RNA binding motif protein 4 in the development of brown adipocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:769-79. [PMID: 24389249 DOI: 10.1016/j.bbamcr.2013.12.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 12/21/2013] [Accepted: 12/24/2013] [Indexed: 10/25/2022]
Abstract
RNA-binding motif protein 4 (RBM4) reportedly reprograms the tissue-specific splicing network which modulates the development of muscles and pancreatic β-islets. Herein, we report that Rbm4a(-/-) mice exhibited hyperlipidemia accompanied with reduced mass of interscapular brown adipose tissue (iBAT). Elevated RBM4a led to the isoform shift of IR, Ppar-γ, and Pref-1 genes which play pivotal roles in the different stages of adipogenesis. Overexpression of RBM4a enhanced the mitochondrial activity of brown adipocyte-like lineage in the presence of uncoupling agent. RBM4a-ablated adipocytes inversely exhibited impaired development and inefficient energy expenditure. Intriguingly, overexpressed RBM4a induced the expression of brown adipocyte-specific factors (Prdm16 and Bmp7) in white adipocyte-like lineage, which suggested the potential action of RBM4a on the white-to-brown trans-differentiation of adipocytes. In differentiating adipocytes, RBM4a constituted a feed-forward circuit through autoregulating the splicing pattern of its own transcript. Based on these results, we propose the emerging role of RBM4 in regulating the adipocyte-specific splicing events and transcription cascade, which subsequently facilitate the development and function of brown adipocyte-like cells.
Collapse
Affiliation(s)
- Jung-Chun Lin
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Wen-Kou Hsieh
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| |
Collapse
|
10
|
Wang CF, Zhang G, Zhao LJ, Qi WJ, Li XP, Wang JL, Wei LH. Overexpression of the insulin receptor isoform A promotes endometrial carcinoma cell growth. PLoS One 2013; 8:e69001. [PMID: 23950881 PMCID: PMC3737217 DOI: 10.1371/journal.pone.0069001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 06/10/2013] [Indexed: 12/17/2022] Open
Abstract
Epidemiological studies have demonstrated that type 2 diabetes mellitus (T2DM) and hyperinsulinemia are associated closely with endometrial carcinoma risk, although the molecular mechanism remains unclear. Insulin receptor isoformA expression is upregulated in many cancer cells and tissues, which suggests that IR-A-mediated signaling pathways may have important implications for cancer pathogenesis. We measured the expression of insulin receptor isoforms (IR-A and IR–B in the normal endometrium tissues, the endometrial carcinoma tissues and the endometrial carcinoma cell lines. We found that the total insulin receptor (IR) and IR-A expression mRNA levels and the ratio of IR-A to total IR in endometrial carcinoma specimens were significantly higher than them in control endometrial tissue specimens(P<0.05). Further analysis indicated that the tendency was more prominently in patients with T2DM. IR-A mRNA was differentially expressed in four endometrial carcinoma cell lines (Ishikawa, KLE, RL95-2 and HEC-1-A. RL95-2 cells have a low endogenous IR-A expression, and these were used to construct a stable cell line overexpressing IR-A. We found that IR-A overexpression significantly increased cell proliferation, the proportion of cells in S phase, activation of the Akt pathway and tumorigenicity of xenografts in nude mice. In contrast, there was no significant difference in the the percentage of apoptotic cells between cells overexpressing IR-A and control cells. Moreover, levels of phosphorylated ERK1/2 protein were significantly decreased in cells overexpressing IR-A relative to controls. These findings reveal the pivotal role of IR-A in endometrial cancer carcinogenesis, and suggest that the association of elevated IR-A levels with cell proliferation and tumorigenicity may be causally linked to its effect on the proportion of cells in S phase and the activation of the Akt pathway.
Collapse
Affiliation(s)
- Chun-Fang Wang
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Peking University, Beijing, China
| | | | | | | | | | | | | |
Collapse
|
11
|
Cohen-Eliav M, Golan-Gerstl R, Siegfried Z, Andersen CL, Thorsen K, Ørntoft TF, Mu D, Karni R. The splicing factor SRSF6 is amplified and is an oncoprotein in lung and colon cancers. J Pathol 2013; 229:630-9. [PMID: 23132731 DOI: 10.1002/path.4129] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 10/03/2012] [Accepted: 10/09/2012] [Indexed: 01/01/2023]
Abstract
An increasing body of evidence connects alterations in the process of alternative splicing with cancer development and progression. However, a direct role of splicing factors as drivers of cancer development is mostly unknown. We analysed the gene copy number of several splicing factors in colon and lung tumours, and found that the gene encoding for the splicing factor SRSF6 is amplified and over-expressed in these cancers. Moreover, over-expression of SRSF6 in immortal lung epithelial cells enhanced proliferation, protected them from chemotherapy-induced cell death and converted them to be tumourigenic in mice. In contrast, knock-down of SRSF6 in lung and colon cancer cell lines inhibited their tumourigenic abilities. SRSF6 up- or down-regulation altered the splicing of several tumour suppressors and oncogenes to generate the oncogenic isoforms and reduce the tumour-suppressive isoforms. Our data suggest that the splicing factor SRSF6 is an oncoprotein that regulates the proliferation and survival of lung and colon cancer cells.
Collapse
Affiliation(s)
- Michal Cohen-Eliav
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Shu Y, Lu W, Liu SL, Xu N, Wang L, Zhang L, Zheng ZH, Pang DW, Wang HZ, Zhang ZL. Site-specific labeling of baculovirus in an integrated microfluidic device. LAB ON A CHIP 2013; 13:860-865. [PMID: 23299251 DOI: 10.1039/c2lc41120b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Labeling of viruses can be used to reveal viral infection pathways and screen potential anti-viral drugs. Complex procedures, including virus cultivation, purification and labeling are involved in traditional virus labeling methods. And the manipulation of living virus brings risk to researcher health. In this work, we report a general method for site-specific labeling of the envelope virus in an integrated microfluidic device with simple procedures and high security. Site-specific labeling of virus was achieved by fusing the biotin acceptor peptide (AP-tag) and the biotin ligase enzyme (BirA enzyme) with the envelope protein GP64 of baculovirus. The AP-tag could be modified by BirA enzyme to introduce the biotin moiety onto the viral envelope. Western blots and fluorescence colocalization analysis proved that the baculoviruses were biotinylated and labeled with high efficiency. The integrated device incorporated several operation steps including cell seeding, cell culture, cell transfection, virus culture and virus labeling. Since virus biotinylation was achieved during the process of virus cultivation, the complex procedures of virus labeling were simplified in our device. Furthermore the whole process could be completed in the integrated microfluidic device, and direct contact between viruses and researchers could be eliminated in our method, which could greatly reduce the risk to researcher health during living virus labeling.
Collapse
Affiliation(s)
- Yun Shu
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P R China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Goustin AS, Derar N, Abou-Samra AB. Ahsg-fetuin blocks the metabolic arm of insulin action through its interaction with the 95-kD β-subunit of the insulin receptor. Cell Signal 2013; 25:981-8. [PMID: 23314177 DOI: 10.1016/j.cellsig.2012.12.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 11/10/2012] [Accepted: 12/19/2012] [Indexed: 12/22/2022]
Abstract
We previously have shown that Ahsg, a liver glycoprotein, inhibits insulin receptor (InsR) tyrosine kinase (TK) activity and the ERK1/2 mitogenic signaling arm of insulin signaling. Here we show that Ahsg blocks insulin-stimulated GLUT4 translocation and Akt activation in intact cells (mouse myoblasts). Furthermore, Ahsg inhibits InsR autophosphorylation of highly-purified insulin holoreceptors in a cell-free, ATP-dependent system, with an IC50 within the range of single-chain Ahsg concentrations in human serum. Binding of (125)I-insulin to living cells overexpressing the InsR shows a dissociation constant (KD) of 250pM, unaltered in the presence of 300 nM Ahsg. A mutant InsR cDNA encoding the signal peptide, the β-subunit and the furin processing site, but deleting the α-subunit, was stably expressed in HEK293 cells. Treatment with peroxovanadate, but not insulin, dramatically increased the 95 kD β-subunit tyrosine phosphoryation. The level of tyrosine phosphorylation of the 95-kD β-subunit can be driven down sharply by treatment of living HEK293 transfectant cells with physiological doses of Ahsg. Treatment of myogenic cells with Ahsg blunts insulin-stimulated InsR autophosphorylation and AKT phosphorylation. Taken together, we show that Ahsg antagonizes the metabolic functions initiated by InsR activation without interference in insulin binding. The experiments suggest a direct interaction of Ahsg with the InsR ectodomain β-subunit in a mode that does not significantly alter the high-affinity binding of insulin to the holoreceptor's two complementing α-subunits.
Collapse
Affiliation(s)
- Anton Scott Goustin
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Wayne State University School of Medicine, Detroit, MI, USA.
| | | | | |
Collapse
|
14
|
Ferguson RD, Gallagher EJ, Scheinman EJ, Damouni R, LeRoith D. The epidemiology and molecular mechanisms linking obesity, diabetes, and cancer. VITAMINS AND HORMONES 2013; 93:51-98. [PMID: 23810003 DOI: 10.1016/b978-0-12-416673-8.00010-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The worldwide epidemic of obesity is associated with increasing rates of the metabolic syndrome and type 2 diabetes. Epidemiological studies have reported that these conditions are linked to increased rates of cancer incidence and mortality. Obesity, particularly abdominal obesity, is associated with insulin resistance and the development of dyslipidemia, hyperglycemia, and ultimately type 2 diabetes. Although many metabolic abnormalities occur with obesity and type 2 diabetes, insulin resistance and hyperinsulinemia appear to be central to these conditions and may contribute to dyslipidemia and altered levels of circulating estrogens and androgens. In this review, we will discuss the epidemiological and molecular links between obesity, type 2 diabetes, and cancer, and how hyperinsulinemia and dyslipidemia may contribute to cancer development. We will discuss how these metabolic abnormalities may interact with estrogen signaling in breast cancer growth. Finally, we will discuss the effects of type 2 diabetes medications on cancer risk.
Collapse
Affiliation(s)
- Rosalyn D Ferguson
- Division of Endocrinology, Diabetes and Bone Diseases, Samuel Bronfman Department of Medicine, Mount Sinai School of Medicine, P.O. Box 1055, New York, USA
| | | | | | | | | |
Collapse
|
15
|
Abstract
The RNA-binding protein RNA-binding motif protein 4 (RBM4) modulates alternative splicing of muscle-specific mRNA isoforms during muscle cell differentiation. To better understand the physiological function of RBM4, we exploited a gene knockout strategy in the present study. Mice with targeted disruption of one of the two Rbm4 genes exhibited hyperglycemia coincident with reduced levels of serum insulin and reduced size of pancreatic islets. The embryonic pancreases of Rbm4-deficient mice showed reduced expression or aberrant splicing of many transcripts encoding factors required for pancreas cell differentiation and function. Using pancreatic acinar AR42J cells, we demonstrated that RBM4 promoted insulin gene expression by altering the isoform balance of the transcription factors Isl1 and Pax4 via alternative splicing control. RBM4 overexpression was sufficient to convert AR42J cells into insulin-producing cells. Moreover, RBM4 may mediate glucose-induced insulin expression and insulin receptor isoform switches. These results suggest that RBM4 may have role in promoting pancreas cell differentiation and endocrine function, essentially via alternative splicing regulation.
Collapse
|
16
|
High-efficiency dual labeling of influenza virus for single-virus imaging. Biomaterials 2012; 33:7828-33. [DOI: 10.1016/j.biomaterials.2012.07.026] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 07/11/2012] [Indexed: 11/23/2022]
|
17
|
Garofalo C, Mancarella C, Grilli A, Manara MC, Astolfi A, Marino MT, Conte A, Sigismund S, Carè A, Belfiore A, Picci P, Scotlandi K. Identification of common and distinctive mechanisms of resistance to different anti-IGF-IR agents in Ewing's sarcoma. Mol Endocrinol 2012; 26:1603-16. [PMID: 22798295 DOI: 10.1210/me.2012-1142] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
IGF system contributes significantly to many human malignancies. Targeting IGF-I receptor (IGF-IR) has been reported to be active against several tumors, but particular efficacy was observed only against a minority of Ewing's sarcoma patients. Identification of mechanisms of acquired resistance to anti-IGF-IR agents is mandatory to individualize their use in clinics and optimize cure costs. In this study, we compared gene expression profiles of cells made resistant with three different anti-IGF-IR drugs (human antibodies AVE1642, Figitumumab, or tyrosine kinase inhibitor NVP-AEW541) to highlight common and distinctive mechanisms of resistance. Among common mechanisms, we identified two molecular signatures that distinguish sensitive from resistant cells. Annotation analysis indicated some common altered pathways, such as insulin signaling, MAPK pathway, endocytosis, and modulation of some members of the interferon-induced transmembrane protein family. Among distinctive pathways/processes, resistance to human antibodies involves mainly genes regulating neural differentiation and angiogenesis, whereas resistance to NVP-AEW541 is mainly associated with alterations in genes concerning inflammation and antigen presentation. Evaluation of the common altered pathways indicated that resistant cells seem to maintain intact the IGF-IR internalization/degradation route of sensitive cells but constantly down-regulated its expression. In resistant cells, the loss of proliferative stimulus, normally sustained by IGF-I/IGF-IR autocrine loop in Ewing's sarcoma cells, is compensated by transcriptional up-regulation of IGF-II and insulin receptor-A; this signaling seems to favor the MAPK pathway over the v-akt murine thymoma viral oncogene homolog 1 pathway. Overall, complexity of IGF system requires analytical evaluation of its components to select those patients that may really benefit from this targeted therapy and support the idea of cotargeting IGF-IR and insulin receptor-A to increase the efficacy.
Collapse
Affiliation(s)
- Cecilia Garofalo
- Centro Riferimento Specialistico Development of Biomolecular Therapies, Experimental Oncology Laboratory, Rizzoli Orthopedic Institute, 40136 Bologna, Italy
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Salomón C, Westermeier F, Puebla C, Arroyo P, Guzmán-Gutiérrez E, Pardo F, Leiva A, Casanello P, Sobrevia L. Gestational diabetes reduces adenosine transport in human placental microvascular endothelium, an effect reversed by insulin. PLoS One 2012; 7:e40578. [PMID: 22808198 PMCID: PMC3395671 DOI: 10.1371/journal.pone.0040578] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 06/10/2012] [Indexed: 11/19/2022] Open
Abstract
Gestational diabetes mellitus (GDM) courses with increased fetal plasma adenosine concentration and reduced adenosine transport in placental macrovascular endothelium. Since insulin modulates human equilibrative nucleoside transporters (hENTs) expression/activity, we hypothesize that GDM will alter hENT2-mediated transport in human placental microvascular endothelium (hPMEC), and that insulin will restore GDM to a normal phenotype involving insulin receptors A (IR-A) and B (IR-B). GDM effect on hENTs expression and transport activity, and IR-A/IR-B expression and associated cell signalling cascades (p42/44 mitogen-activated protein kinases (p42/44mapk) and Akt) role in hPMEC primary cultures was assayed. GDM associates with elevated umbilical whole and vein, but not arteries blood adenosine, and reduced hENTs adenosine transport and expression. IR-A/IR-B mRNA expression and p42/44mapk/Akt ratios (‘metabolic phenotype’) were lower in GDM. Insulin reversed GDM-reduced hENT2 expression/activity, IR-A/IR-B mRNA expression and p42/44mapk/Akt ratios to normal pregnancies (‘mitogenic phenotype’). It is suggested that insulin effects required IR-A and IR-B expression leading to differential modulation of signalling pathways restoring GDM-metabolic to a normal-mitogenic like phenotype. Insulin could be acting as protecting factor for placental microvascular endothelial dysfunction in GDM.
Collapse
Affiliation(s)
- Carlos Salomón
- Cellular and Molecular Physiology Laboratory (CMPL) and Perinatology Research Laboratory (PRL), Medical Research Centre (CIM), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisco Westermeier
- Cellular and Molecular Physiology Laboratory (CMPL) and Perinatology Research Laboratory (PRL), Medical Research Centre (CIM), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos Puebla
- Cellular and Molecular Physiology Laboratory (CMPL) and Perinatology Research Laboratory (PRL), Medical Research Centre (CIM), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo Arroyo
- Cellular and Molecular Physiology Laboratory (CMPL) and Perinatology Research Laboratory (PRL), Medical Research Centre (CIM), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Enrique Guzmán-Gutiérrez
- Cellular and Molecular Physiology Laboratory (CMPL) and Perinatology Research Laboratory (PRL), Medical Research Centre (CIM), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fabián Pardo
- Cellular and Molecular Physiology Laboratory (CMPL) and Perinatology Research Laboratory (PRL), Medical Research Centre (CIM), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Andrea Leiva
- Cellular and Molecular Physiology Laboratory (CMPL) and Perinatology Research Laboratory (PRL), Medical Research Centre (CIM), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Paola Casanello
- Cellular and Molecular Physiology Laboratory (CMPL) and Perinatology Research Laboratory (PRL), Medical Research Centre (CIM), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL) and Perinatology Research Laboratory (PRL), Medical Research Centre (CIM), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail:
| |
Collapse
|
19
|
Affiliation(s)
- Pierre De Meyts
- Department of Diabetes Biology and Hagedorn Research Institute, Novo Nordisk A/S, 2820 Gentofte, Denmark.
| |
Collapse
|
20
|
Sumner T, Shephard E, Bogle IDL. A methodology for global-sensitivity analysis of time-dependent outputs in systems biology modelling. J R Soc Interface 2012; 9:2156-66. [PMID: 22491976 DOI: 10.1098/rsif.2011.0891] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
One of the main challenges in the development of mathematical and computational models of biological systems is the precise estimation of parameter values. Understanding the effects of uncertainties in parameter values on model behaviour is crucial to the successful use of these models. Global sensitivity analysis (SA) can be used to quantify the variability in model predictions resulting from the uncertainty in multiple parameters and to shed light on the biological mechanisms driving system behaviour. We present a new methodology for global SA in systems biology which is computationally efficient and can be used to identify the key parameters and their interactions which drive the dynamic behaviour of a complex biological model. The approach combines functional principal component analysis with established global SA techniques. The methodology is applied to a model of the insulin signalling pathway, defects of which are a major cause of type 2 diabetes and a number of key features of the system are identified.
Collapse
Affiliation(s)
- T Sumner
- CoMPLEX, University College London, London, UK.
| | | | | |
Collapse
|
21
|
Siddle K. Molecular basis of signaling specificity of insulin and IGF receptors: neglected corners and recent advances. Front Endocrinol (Lausanne) 2012; 3:34. [PMID: 22649417 PMCID: PMC3355962 DOI: 10.3389/fendo.2012.00034] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 02/13/2012] [Indexed: 12/15/2022] Open
Abstract
Insulin and insulin-like growth factor (IGF) receptors utilize common phosphoinositide 3-kinase/Akt and Ras/extracellular signal-regulated kinase signaling pathways to mediate a broad spectrum of "metabolic" and "mitogenic" responses. Specificity of insulin and IGF action in vivo must in part reflect expression of receptors and responsive pathways in different tissues but it is widely assumed that it is also determined by the ligand binding and signaling mechanisms of the receptors. This review focuses on receptor-proximal events in insulin/IGF signaling and examines their contribution to specificity of downstream responses. Insulin and IGF receptors may differ subtly in the efficiency with which they recruit their major substrates (IRS-1 and IRS-2 and Shc) and this could influence effectiveness of signaling to "metabolic" and "mitogenic" responses. Other substrates (Grb2-associated binder, downstream of kinases, SH2Bs, Crk), scaffolds (RACK1, β-arrestins, cytohesins), and pathways (non-receptor tyrosine kinases, phosphoinositide kinases, reactive oxygen species) have been less widely studied. Some of these components appear to be specifically involved in "metabolic" or "mitogenic" signaling but it has not been shown that this reflects receptor-preferential interaction. Very few receptor-specific interactions have been characterized, and their roles in signaling are unclear. Signaling specificity might also be imparted by differences in intracellular trafficking or feedback regulation of receptors, but few studies have directly addressed this possibility. Although published data are not wholly conclusive, no evidence has yet emerged for signaling mechanisms that are specifically engaged by insulin receptors but not IGF receptors or vice versa, and there is only limited evidence for differential activation of signaling mechanisms that are common to both receptors. Cellular context, rather than intrinsic receptor activity, therefore appears to be the major determinant of whether responses to insulin and IGFs are perceived as "metabolic" or "mitogenic."
Collapse
Affiliation(s)
- Kenneth Siddle
- University of Cambridge Metabolic Research Laboratories and Department of Clinical Biochemistry, Institute of Metabolic Science, Addenbrooke's Hospital Cambridge, UK.
| |
Collapse
|
22
|
Morcavallo A, Genua M, Palummo A, Kletvikova E, Jiracek J, Brzozowski AM, Iozzo RV, Belfiore A, Morrione A. Insulin and insulin-like growth factor II differentially regulate endocytic sorting and stability of insulin receptor isoform A. J Biol Chem 2012; 287:11422-36. [PMID: 22318726 DOI: 10.1074/jbc.m111.252478] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The insulin receptor isoform A (IR-A) binds both insulin and insulin-like growth factor (IGF)-II, although the affinity for IGF-II is 3-10-fold lower than insulin depending on a cell and tissue context. Notably, in mouse embryonic fibroblasts lacking the IGF-IR and expressing solely the IR-A (R-/IR-A), IGF-II is a more potent mitogen than insulin. As receptor endocytosis and degradation provide spatial and temporal regulation of signaling events, we hypothesized that insulin and IGF-II could affect IR-A biological responses by differentially regulating IR-A trafficking. Using R-/IR-A cells, we discovered that insulin evoked significant IR-A internalization, a process modestly affected by IGF-II. However, the differential internalization was not due to IR-A ubiquitination. Notably, prolonged stimulation of R-/IR-A cells with insulin, but not with IGF-II, targeted the receptor to a degradative pathway. Similarly, the docking protein insulin receptor substrate 1 (IRS-1) was down-regulated after prolonged insulin but not IGF-II exposure. Similar results were also obtained in experiments using [NMeTyr(B26)]-insulin, an insulin analog with IR-A binding affinity similar to IGF-II. Finally, we discovered that IR-A was internalized through clathrin-dependent and -independent pathways, which differentially regulated the activation of downstream effectors. Collectively, our results suggest that a lower affinity of IGF-II for the IR-A promotes lower IR-A phosphorylation and activation of early downstream effectors vis à vis insulin but may protect IR-A and IRS-1 from down-regulation thereby evoking sustained and robust mitogenic stimuli.
Collapse
Affiliation(s)
- Alaide Morcavallo
- Department of Urology and Endocrine Mechanisms and Hormone Action Program, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Insight into the molecular basis for the kinetic differences between the two insulin receptor isoforms. Biochem J 2012; 440:397-403. [PMID: 21838706 DOI: 10.1042/bj20110550] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
More than 20 years after the description of the two IR (insulin receptor) isoforms, designated IR-A (lacking exon 11) and IR-B (with exon 11), nearly every functional aspect of the alternative splicing both in vitro and in vivo remains controversial. In particular, there is no consensus on the precise ligand-binding properties of the isoforms. Increased affinity and dissociation kinetics have been reported for IR-A in comparison with IR-B, but the opposite results have also been reported. These are not trivial issues considering the reported possible increased mitogenic potency of IR-A, and the reported link between slower dissociation and increased mitogenesis. We have re-examined the ligand-binding properties of the two isoforms using a novel rigorous mathematical analysis based on the concept of a harmonic oscillator. We found that insulin has 1.5-fold higher apparent affinity towards IR-A and a 2-fold higher overall dissociation rate. Analysis based on the model showed increased association (3-fold) and dissociation (2-fold) rate constants for binding site 1 of IR in comparison with IR-B. We also provide a structural interpretation of these findings on the basis of the structure of the IR ectodomain and the proximity of the sequence encoded by exon 11 to the C-terminal peptide that is a critical trans-component of site 1.
Collapse
|
24
|
Scotlandi K, Belfiore A. Targeting the Insulin-Like Growth Factor (IGF) System Is Not as Simple as Just Targeting the Type 1 IGF Receptor. Am Soc Clin Oncol Educ Book 2012:599-604. [PMID: 24451803 DOI: 10.14694/edbook_am.2012.32.134] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Increased signaling of the insulin-like growth factor (IGF) system via alterations in expression levels of its components has been demonstrated in various tumor types. Numerous experimental studies have supported the involvement of the IGF system signaling axis in tumor initiation and progression. These studies, combined with data that link alterations in the levels of circulating IGFs with cancer risk and prognosis, have focused on the IGF-1 receptor (IGF-1R) as a therapeutic target for patients with cancer. As a consequence, most therapeutic strategies have been designed to specifically inhibit IGF-1R but have for the most part ignored the insulin receptor (IR), based on concerns that targeting IR would lead to unacceptable toxicity both because of its role in physiologic metabolism and because we frequently try to oversimplify biologic complexity whenever we are urged to find practical, friendly solutions for clinical practice. Although this is an understandable and necessary starting point in the complex and long-lasting processes that leads to translational biology, the crude reality of the results obtained from phase I and II studies suggest a need for researchers to be humble and go back to the drawing board. Cancer research has substantially neglected the role of IR, and it remains unclear whether and to what extent avoiding the inhibition of IR has compromised the efficacy of anti-IGF-1R therapy. Clarifying its role might also help us take advantage of older drugs that could offer new perspectives in cancer care.
Collapse
Affiliation(s)
- Katia Scotlandi
- From the CRS Development of Biomolecular Therapies, Experimental Oncology Lab, Orthopaedic Rizzoli Institute, Bologna, Italy; Department of Endocrinology, Department of Health University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Antonino Belfiore
- From the CRS Development of Biomolecular Therapies, Experimental Oncology Lab, Orthopaedic Rizzoli Institute, Bologna, Italy; Department of Endocrinology, Department of Health University Magna Graecia of Catanzaro, Catanzaro, Italy
| |
Collapse
|
25
|
Bruchez MP. Quantum dots find their stride in single molecule tracking. Curr Opin Chem Biol 2011; 15:775-80. [PMID: 22055494 DOI: 10.1016/j.cbpa.2011.10.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 09/30/2011] [Accepted: 10/17/2011] [Indexed: 01/01/2023]
Abstract
Thirteen years after the demonstration of quantum dots as biological imaging agents, and nine years after the initial commercial introduction of bioconjugated quantum dots, the brightness and photostability of the quantum dots has enabled a range of investigations using single molecule tracking. These materials are being routinely utilized by a number of groups to track the dynamics of single molecules in reconstituted biophysical systems and on living cells, and are especially powerful for investigations of single molecules over long timescales with short exposure times and high pointing accuracy. New approaches are emerging where the quantum dots are used as 'hard-sphere' probes for intracellular compartments. Innovations in quantum dot surface modification are poised to substantially expand the utility of these materials.
Collapse
Affiliation(s)
- Marcel P Bruchez
- Carnegie Mellon University, Department of Chemistry, Pittsburgh, PA 15213, USA.
| |
Collapse
|
26
|
Abstract
The widespread epidemic of obesity and type 2 diabetes has raised concern for the impact of these disorders as risk factors for cancer and has renewed the interest for studies regarding the involvement of hyperinsulinemia and insulin receptor (IR) in cancer progression. Overexpression of IR in cancer cells may explain their increased sensitivity to hyperinsulinemia. Moreover, IR isoform A (IR-A) together with autocrine production of its ligand IGF2 is emerging as an important mechanism of normal and cancer stem cell expansion and is a feature of several malignancies. De novo activation of the IR-A/IGF2 autocrine loop also represents a mechanism of resistance to anticancer therapies. Increasing knowledge of the IR role in cancer has important implications for cancer prevention, which should include control of insulin resistance and hyperinsulinemia in the population and meticulous evaluation of new antidiabetic drugs for their metabolic:mitogenic ratio. We are now aware that several anticancer treatments may induce or worsen insulin resistance that may limit therapy efficacy. Future anticancer therapies need to target the IR-A pathway in order to inhibit the tumor promoting effect of IR without impairing the metabolic effect of insulin.
Collapse
Affiliation(s)
- Antonino Belfiore
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University Magna Graecia of Catanzaro, Campus Universitario, località Germaneto, 88100 Catanzaro, Italy.
| | | |
Collapse
|
27
|
Glendorf T, Stidsen CE, Norrman M, Nishimura E, Sørensen AR, Kjeldsen T. Engineering of insulin receptor isoform-selective insulin analogues. PLoS One 2011; 6:e20288. [PMID: 21625452 PMCID: PMC3098868 DOI: 10.1371/journal.pone.0020288] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 04/28/2011] [Indexed: 11/19/2022] Open
Abstract
Background The insulin receptor (IR) exists in two isoforms, A and B, and the isoform expression pattern is tissue-specific. The C-terminus of the insulin B chain is important for receptor binding and has been shown to contact the IR just adjacent to the region where the A and B isoforms differ. The aim of this study was to investigate the importance of the C-terminus of the B chain in IR isoform binding in order to explore the possibility of engineering tissue-specific/liver-specific insulin analogues. Methodology/Principal Findings Insulin analogue libraries were constructed by total amino acid scanning mutagenesis. The relative binding affinities for the A and B isoform of the IR were determined by competition assays using scintillation proximity assay technology. Structural information was obtained by X-ray crystallography. Introduction of B25A or B25N mutations resulted in analogues with a 2-fold preference for the B compared to the A isoform, whereas the opposite was observed with a B25Y substitution. An acidic amino acid residue at position B27 caused an additional 2-fold selective increase in affinity for the receptor B isoform for analogues bearing a B25N mutation. Furthermore, the combination of B25H with either B27D or B27E also resulted in B isoform-preferential analogues (2-fold preference) even though the corresponding single mutation analogues displayed no differences in relative isoform binding affinity. Conclusions/Significance We have discovered a new class of IR isoform-selective insulin analogues with 2–4-fold differences in relative binding affinities for either the A or the B isoform of the IR compared to human insulin. Our results demonstrate that a mutation at position B25 alone or in combination with a mutation at position B27 in the insulin molecule confers IR isoform selectivity. Isoform-preferential analogues may provide new opportunities for developing insulin analogues with improved clinical benefits.
Collapse
Affiliation(s)
- Tine Glendorf
- Diabetes Research Unit, Novo Nordisk A/S, Maaloev, Denmark.
| | | | | | | | | | | |
Collapse
|