1
|
Agerholm J, Hjortebjerg R, Espelund U, Rasmussen TR, Folkersen B, Bjerre M, Frystyk J. Development of a novel assay for IGFBP-2 complexed with IGF-I and-II in human serum. Growth Horm IGF Res 2020; 51:38-45. [PMID: 32035328 DOI: 10.1016/j.ghir.2020.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 01/18/2020] [Accepted: 01/20/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND Insulin-like growth factor binding-protein 2 (IGFBP-2) was originally identified as an IGF-carrier, governing IGF half-life, tissue accessibility and biological effects. Later, IGFBP-2 was discovered to possess IGF-independent effects. IGFBP-2 circulates in several forms, as free protein, complexed with IGF-I or IGF-II, or as IGFBP-2 fragments. The various IGFBP-2 forms are all included when measuring serum IGFBP-2 concentrations by immunoassay (i.e., immunoreactive (ir-)IGFBP-2). In this study, we describe a novel method to measure the amount of IGF that circulates bound to IGFBP-2. METHOD IGFBP-2 was immunoprecipitated from human serum using magnetic beads, which were subsequently eluted by acidification. After neutralization, eluates were assayed for ir-IGFBP-2, IGF-I and IGF-II and compared to serum concentrations. This allowed measurement of IGFBP-2-compexed IGF-I and IGF-II, respectively. To test the method clinically, serum from 146 patients with lung cancer, 151 patients with non-cancer pulmonary diseases and 28 healthy controls were analyzed. RESULTS We immuno-precipitated 97 ± 3.3% of serum IGFBP-2 and recovered > 75% of IGFBP-2-complexed IGFs, with intra- and inter-assay coefficient of variations (CVs) averaging < 5% and < 13%, respectively. No co-precipitation with IGFBP-1, -3 or - 4 was detected. Serum levels of ir-IGFBP-2 (median [25;75%]) differed between groups (cancer patients vs. non-cancer patients vs. healthy controls): 342 [260;480] vs. 262 [189;388] vs. 190 [141;269] μg/l (p < .0001). In parallel with this, concentrations of IGF-II carried by IGFBP-2 averaged: 45.0 [33.3;52.5] vs. 34.2 [25.4;46.1] vs. 19.8 [14.1;26.0] μg/l (p < .0001), and concentrations of IGF-I 8.0 [5.2;11.8] vs. 5.4 [3.6;7.3] vs. 7.0 [3.8;13.0] μg/l (p < .0001). Thus, IGFBP-2 carried more IGF-II than IGF-I in all groups (p < .0001). When expressed relative to IGF-concentrations, IGFBP-2 carried 9.0 [5.3;15.5] % of the IGF-I and 4.8 [2.9;5.8] % of the IGF-II in serum from healthy subjects. Notably, in patients, IGFBP-2 carried relatively less IGF-I, but more IGF-II (p < .0001). CONCLUSION Using our novel assay, we demonstrate: that IGFBP-2 carries ≈10% of circulating IGF-I and ≈5% of circulating IGF-II in healthy subjects; that IGF-II is the primary ligand for IGFBP-2; and that IGFBP-2 carries even more IGF-II in patients than in healthy subjects. Thus, our assay may provide information on IGFBP-2 beyond what is achievable by simply measuring ir-IGFBP-2.
Collapse
Affiliation(s)
- Jonas Agerholm
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Aarhus DK-8200, Denmark
| | - Rikke Hjortebjerg
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Aarhus DK-8200, Denmark
| | - Ulrick Espelund
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Aarhus DK-8200, Denmark
| | - Torben Riis Rasmussen
- Department of Pulmonary Medicine, Aarhus University Hospital, Aarhus DK-8000, Denmark
| | - Birgitte Folkersen
- Department of Pulmonary Medicine, Aarhus University Hospital, Aarhus DK-8000, Denmark
| | - Mette Bjerre
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Aarhus DK-8200, Denmark
| | - Jan Frystyk
- Medical Research Laboratory, Department of Clinical Medicine, Health, Aarhus University, Aarhus DK-8200, Denmark; The Research Unit for Endocrinology, Department of Endocrinology, Odense University Hospital, Odense, Denmark; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense DK-5000, Denmark.
| |
Collapse
|
2
|
Genome-Wide Profiling of Laron Syndrome Patients Identifies Novel Cancer Protection Pathways. Cells 2019; 8:cells8060596. [PMID: 31208077 PMCID: PMC6627189 DOI: 10.3390/cells8060596] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 12/30/2022] Open
Abstract
Laron syndrome (LS), or primary growth hormone resistance, is a prototypical congenital insulin-like growth factor 1 (IGF1) deficiency. The recent epidemiological finding that LS patients do not develop cancer is of major scientific and clinical relevance. Epidemiological data suggest that congenital IGF1 deficiency confers protection against the development of malignancies. This ‘experiment of nature’ reflects the critical role of IGF1 in tumor biology. The present review article provides an overview of recently conducted genome-wide profiling analyses aimed at identifying mechanisms and signaling pathways that are directly responsible for the link between life-time low IGF1 levels and protection from tumor development. The review underscores the concept that ‘data mining’ an orphan disease might translate into new developments in oncology.
Collapse
|
3
|
Kalledsøe L, Dragsted LO, Hansen L, Kyrø C, Grønbæk H, Tjønneland A, Olsen A. The insulin-like growth factor family and breast cancer prognosis: A prospective cohort study among postmenopausal women in Denmark. Growth Horm IGF Res 2019; 44:33-42. [PMID: 30622040 DOI: 10.1016/j.ghir.2018.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 12/11/2018] [Accepted: 12/18/2018] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Circulating levels of insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) have been associated with breast cancer (BC) risk. The evidence in relation to BC prognosis is limited. We aimed to evaluate the association between pre-diagnostic serum levels of IGF-I, IGF-II, IGFBP-2, IGFBP-3 and BC prognosis (i.e. recurrence, BC specific mortality and all-cause mortality) among women diagnosed with BC. We hypothesized that higher serum levels of IGFs and IGFBPs were associated with poor BC prognosis and that the associations were modified by estrogen receptor (ER) status. DESIGN From the Danish Diet, Cancer and Health cohort, 412 postmenopausal women diagnosed with incident BC within 5 years of cohort baseline (1993-1997) were identified. Baseline serum samples were analyzed for IGF-I, IGF-II, IGFBP-2 and IGFBP-3. Follow-up was carried out through 2014 by linkage to national Danish registries. Exposures were related to BC prognosis by Cox Proportional Hazard models; effect modification by ER status was investigated and sensitivity analyses by follow-up time were made. RESULTS During a median of 15 years, 106 women experienced recurrence and 172 died (118 due to BC). Overall, no associations were observed between IGF-I, IGF-II, IGFBP-2, IGFBP-3 and BC prognosis and no effect modification by ER status was observed. However, higher levels of IGF-II were associated with higher BC specific mortality [Hazard Ratio (HR) (95% Confidence Intervals (CI)): 1.43 (1.01-2.04)] within 10 years of follow-up. Likewise, higher levels of IGFBP-2 were associated with higher BC specific mortality [HR (95% CI): 1.87 (1.19-2.94)] within 5 years of follow-up. In contrast, higher levels of IGFBP-3 were associated with lower risk of recurrence [HR (95% CI): 0.76 (0.60-0.97)] at 5 years of follow-up and BC specific mortality [HR (95% CI): 0.80 (0.65-0.98)] within 10 years of follow-up. CONCLUSIONS The present study did not support an association between higher serum levels of IGFs, IGFBPs and adverse BC prognosis. However, it is possible that the role of the IGF family in the etiology of the 5-10 year BC prognosis is different from that of longer-term BC prognosis.
Collapse
Affiliation(s)
- Loa Kalledsøe
- Diet, Genes and Environment, Danish Cancer Society Research Center, Danish Cancer Society, Strandboulevarden 49, 2100 Copenhagen Ø, Denmark
| | - Lars Ove Dragsted
- Department of Nutrition, Exercise and Sports, Section of Preventive and Clinical Nutrition, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg C, Denmark
| | - Louise Hansen
- Diet, Genes and Environment, Danish Cancer Society Research Center, Danish Cancer Society, Strandboulevarden 49, 2100 Copenhagen Ø, Denmark
| | - Cecilie Kyrø
- Diet, Genes and Environment, Danish Cancer Society Research Center, Danish Cancer Society, Strandboulevarden 49, 2100 Copenhagen Ø, Denmark
| | - Henning Grønbæk
- Department of Hepatology and Gastroenterology, Department of Clinical Medicine, Aarhus University, Nørrebrogade 44, 8000 Aarhus C, Denmark
| | - Anne Tjønneland
- Diet, Genes and Environment, Danish Cancer Society Research Center, Danish Cancer Society, Strandboulevarden 49, 2100 Copenhagen Ø, Denmark
| | - Anja Olsen
- Diet, Genes and Environment, Danish Cancer Society Research Center, Danish Cancer Society, Strandboulevarden 49, 2100 Copenhagen Ø, Denmark.
| |
Collapse
|
4
|
Somri L, Sarfstein R, Lapkina-Gendler L, Nagaraj K, Laron Z, Bach LA, Werner H. Differential expression of IGFBPs in Laron syndrome-derived lymphoblastoid cell lines: Potential correlation with reduced cancer incidence. Growth Horm IGF Res 2018; 39:6-12. [PMID: 29208357 DOI: 10.1016/j.ghir.2017.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 11/01/2017] [Accepted: 11/23/2017] [Indexed: 12/22/2022]
Abstract
Laron syndrome (LS), or primary growth hormone (GH) insensitivity, is a growth disorder that results from mutation of the GH-receptor (GHR) gene leading to congenital insulin-like growth factor-1 (IGF-1) deficiency. Recent epidemiological studies have shown that LS patients are protected from cancer development. Genome-wide profiling identified genes and signaling pathways that are differentially represented in LS patients, and that may contribute to cancer protection. The present study was aimed at evaluating the hypothesis that IGF binding proteins (IGFBPs) are differentially expressed in LS, most probably as a result of low circulating levels of IGF-1. Furthermore, we postulated that IGFBPs might be differentially regulated by oxidative stress in this condition and, therefore, may contribute to cancer evasion. Our results show that IGFBP-3, which is predominantly protective, was highly expressed in LS-derived lymphoblastoid cells in comparison to control cells from the same ethnic group. On the other hand, levels of IGFBP-2, -4, -5, and -6 were diminished in LS patients, as demonstrated by RQ-PCR, Western immunoblots and confocal immunofluorescence. In addition, our data provide evidence for a pattern of IGFBP response to H2O2 treatment that might be associated with distinct expression of apoptosis markers (BCL2, pro-caspase-9, pro-caspase-3) in LS. In summary, differential expression of specific IGFBPs in LS might be correlated with cellular mechanisms underlying cancer protection and, probably, additional phenotypes due to congenital IGF-1 deficiency.
Collapse
Affiliation(s)
- Lina Somri
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Rive Sarfstein
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Lena Lapkina-Gendler
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Karthik Nagaraj
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Zvi Laron
- Endocrine and Diabetes Research Unit, Schneider Children's Medical Center, Petah Tikva 49292, Israel
| | - Leon A Bach
- Department of Medicine (Alfred), Monash University, Melbourne, Australia; Department of Endocrinology and Diabetes, Alfred Hospital, Melbourne, Australia
| | - Haim Werner
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; Yoran Institute for Human Genome Research, Tel Aviv University, Tel Aviv 69978, Israel.
| |
Collapse
|
5
|
Abstract
The worldwide clinical and scientific interest in peptides belonging to the insulin-like growth factor (IGF) system has brought along a call for standardization of assays used to quantify the different IGF related proteins. This relates in particular to the measurement of IGF-I, which has stood the test of time as an important biochemical tool in the diagnosis and treatment of growth hormone (GH) related disorders. The first international consensus statement on the measurement of IGF-I in 2011 represents an important milestone and will undoubtedly improve commutability of reference ranges for IGF-I and clinically applicable cut-off values. By contrast, there is no consensus addressing the measurements of the other IGF-related peptides. Nevertheless, measurement of these peptides may be of interest, either as additional tools in GH disorders or as prognostic biomarkers of various diseases. Therefore, standardization of assays for the other IGF-related peptides is highly relevant. This chapter discusses the recent consensus on IGF-I measurements and how this approach may be applied to measurement of the other IGF-related peptides. In addition, assay pitfalls, pre- and post-analytical challenges, alternative methods for IGF-I measurements and potential assays of tomorrow will be discussed.
Collapse
Affiliation(s)
- Rikke Hjortebjerg
- Medical Research Laboratory, Department of Clinical Medicine, Faculty of Health, Aarhus University, DK-8000 Aarhus C, Denmark
| | | |
Collapse
|
6
|
Bielohuby M, Popp S, Bidlingmaier M. Influence of pre-analytical conditions on the measurement of components of the GH/IGF axis in rats. Growth Horm IGF Res 2013; 23:141-148. [PMID: 23773927 DOI: 10.1016/j.ghir.2013.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 05/21/2013] [Accepted: 05/22/2013] [Indexed: 11/23/2022]
Abstract
UNLABELLED Pre-analytical variability characterises effects which are introduced to an analysis by manipulation and storage of a biological sample after taking it ex-vivo, but before actually quantifying the respective analyte. In humans, recent studies demonstrated that pre-analytical factors can be an important confounder for immunoassay measurements of circulating hormones of the GH/IGF-system. In contrast, this topic has rarely been addressed in rodent studies. We therefore now systematically investigated if and how commonly used sample processing and pre-treatment protocols affect measured hormone concentrations of the GH/IGF system in rats. Furthermore, we explored if short term fasting, age and circadian rhythmicity have an impact upon the concentrations of IGF-I, IGFBP-2 and IGFBP-3 in rats. RESULTS On average, concentrations of IGF-I were lower by 9.2% (p < 0.01), while those of IGF-II and IGFBP-3 were lower by 24% (p < 0.01) in EDTA plasma when compared to plain serum from the same rats. In contrast, concentrations of GH were significantly higher in plain plasma samples compared with serum (+137.8%; p < 0.01). Repeated freeze/thaw cycles significantly influenced the measurements of serum IGF-II (+25.9%; p < 0.01) and IGFBP-3 (+19.3%; p < 0.01) when compared to native serum. Pre-treatment of EDTA plasma with protease inhibitors, or immediate storage of EDTA blood on ice, did not significantly affect the outcome of any measurement. Acidification of plasma samples with HCl led to significantly lower IGF-I in samples (-11.9%, p < 0.001) and detection of GH was completely hampered in these samples. With respect to biological variability, age (12-week-old vs. 1-year-old male Wistar rats), but not fasting (up to 18 h) or circadian rhythmicity affected circulating concentrations of IGF-I and IGFBP-3. CONCLUSION Pre-analytical variability is a potentially confounding factor which also must be considered in rodent studies when analysing and comparing hormones of the GH/IGF system. If and to what extent a specific pre-analytical procedure affects immunoassay measurements in rodent studies cannot be predicted in advance but rather needs to be tested for each analyte separately.
Collapse
Affiliation(s)
- Maximilian Bielohuby
- Endocrine Research Unit, Medizinische Klinik und Poliklinik IV, Klinikum der LMU, Munich, Germany.
| | | | | |
Collapse
|
7
|
Puche JE, Castilla-Cortázar I. Human conditions of insulin-like growth factor-I (IGF-I) deficiency. J Transl Med 2012; 10:224. [PMID: 23148873 PMCID: PMC3543345 DOI: 10.1186/1479-5876-10-224] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/07/2012] [Indexed: 12/13/2022] Open
Abstract
Insulin-like growth factor I (IGF-I) is a polypeptide hormone produced mainly by the liver in response to the endocrine GH stimulus, but it is also secreted by multiple tissues for autocrine/paracrine purposes. IGF-I is partly responsible for systemic GH activities although it possesses a wide number of own properties (anabolic, antioxidant, anti-inflammatory and cytoprotective actions). IGF-I is a closely regulated hormone. Consequently, its logical therapeutical applications seems to be limited to restore physiological circulating levels in order to recover the clinical consequences of IGF-I deficiency, conditions where, despite continuous discrepancies, IGF-I treatment has never been related to oncogenesis. Currently the best characterized conditions of IGF-I deficiency are Laron Syndrome, in children; liver cirrhosis, in adults; aging including age-related-cardiovascular and neurological diseases; and more recently, intrauterine growth restriction. The aim of this review is to summarize the increasing list of roles of IGF-I, both in physiological and pathological conditions, underlying that its potential therapeutical options seem to be limited to those proven states of local or systemic IGF-I deficiency as a replacement treatment, rather than increasing its level upper the normal range.
Collapse
Affiliation(s)
- Juan E Puche
- Applied Molecular Medicine Institute (IMMA), School of Medicine, Department of Medical Physiology, Universidad CEU San Pablo, Madrid, Spain
| | - Inma Castilla-Cortázar
- Applied Molecular Medicine Institute (IMMA), School of Medicine, Department of Medical Physiology, Universidad CEU San Pablo, Madrid, Spain
| |
Collapse
|
8
|
Frystyk J, Freda P, Clemmons DR. The current status of IGF-I assays--a 2009 update. Growth Horm IGF Res 2010; 20:8-18. [PMID: 19818658 PMCID: PMC7748085 DOI: 10.1016/j.ghir.2009.09.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 09/16/2009] [Indexed: 10/20/2022]
Abstract
For almost three decades, the measurement of circulating IGF-I has constituted a highly important biochemical tool in the management of GH disorders. In fact, in acromegaly the importance of circulating IGF-I has increased following the introduction of the GH receptor antagonist pegvisomant, as the use of this drug makes it impossible to use circulating GH as a monitor of disease activity. In addition, determination of circulating IGF-I constitutes a valuable scientific tool in various research areas, from epidemiological investigations through clinical trials and experimental studies. The multiple facets of IGF-I physiology and patho-physiology may explain why numerous endocrine laboratories have invested in IGF-I assays, by means of either in-house assays or commercial kits. However, despite its widespread use, the measurement of IGF-I is by no means trivial. On the contrary, the pronounced binding of IGF-I to the high-affinity IGF-binding proteins (IGFBPs) constitutes a notorious source of error, which has necessitated the development of methods that more or less successfully circumvent interference from the IGFBPs. Furthermore, there are some unsolved issues with the international standardization of the different IGF-I assays and there is no consensus regarding the procedures used when collecting and storing samples for measurement of circulating IGF-I. The aim of this review is to discuss the current state of the art of IGF-I immunoassays and to present the current analytical problems with IGF-I measurements. Finally, we would like to suggest an agenda that may be used when trying to produce internationally accepted uniform requirements for future IGF-I assays.
Collapse
Affiliation(s)
- Jan Frystyk
- The Medical Research Laboratories, Clinical Institute of Medicine, and Medical Department M (Diabetes & Endocrinology), Aarhus University Hospital, Nørrebrogade 44, DK-8000 Aarhus C, Denmark.
| | | | | |
Collapse
|