1
|
Tang Z, Gillatt D, Rowe E, Koupparis A, Holly JM, Perks CM. IGFBP-2 acts as a tumour suppressor and plays a role in determining chemosensitivity in bladder cancer cells. Oncotarget 2019; 10:7043-7057. [PMID: 31903164 PMCID: PMC6925026 DOI: 10.18632/oncotarget.27355] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 10/21/2019] [Indexed: 12/13/2022] Open
Abstract
There are mixed reports on the role that IGFBP-2 plays in cancer progression, with some indicating a tumour suppressive role and others showing that IGFBP-2 may act as an oncogene. These apparent contradictions may be context and tissue specific. In this study we determined the role that IGFBP-2 played on the phenotype and chemosensitivity of a selection of bladder cancer cell lines and investigated how the abundance of IGFBP-2 was regulated. We found that IGFBP-2 was more abundant in the epithelial bladder cancer cells, RT4 and UMUC3 and absent in the more mesenchymal T24 and TCCSUP cells. Silencing IGFBP-2 using siRNA in epithelial RT4 cells promoted cell proliferation, invasion, colony formation, resulted in a reduction in epithelial (E-cadherin) and an increase in mesenchymal (N-cadherin) markers and increased sensitivity to cisplatin-induced cell death. Conversely, we observed the opposite effects when adding exogenous IGFBP-2 to the mesenchymal T24 cells. We determined that IGFBP-2 was epigenetically silenced via DNA methylation as the cells adopted a mesenchymal phenotype. Collectively these data suggest that IGFBP-2 acts as a tumour suppressor and marker of chemosensitivity in epithelial bladder cancer cells and that IGFBP-2 is epigenetically silenced by methylation to promote bladder cancer progression.
Collapse
Affiliation(s)
- Zhen Tang
- IGFs & Metabolic Endocrinology Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol BS10 5N, England
| | - David Gillatt
- Department of Surgery, Macquarie University Hospital, Macquarie University, Sydney, NSW 2109, Australia
| | - Edward Rowe
- Department of Urology, Southmead Hospital and Bristol Urological Institute, Bristol BS10 5NB, England
| | - Anthony Koupparis
- Department of Urology, Southmead Hospital and Bristol Urological Institute, Bristol BS10 5NB, England
| | - Jeff M.P. Holly
- IGFs & Metabolic Endocrinology Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol BS10 5N, England
- Co-senior authors
| | - Claire M. Perks
- IGFs & Metabolic Endocrinology Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol BS10 5N, England
| |
Collapse
|
2
|
Biernacka KM, Holly JM, Martin RM, Frankow A, Bull CJ, Hamdy FC, Donovan JL, Neal DE, Metcalfe C, Lane A. Effect of green tea and lycopene on the insulin-like growth factor system: the ProDiet randomized controlled trial. Eur J Cancer Prev 2019; 28:569-575. [PMID: 30921005 PMCID: PMC6784856 DOI: 10.1097/cej.0000000000000502] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 01/18/2019] [Indexed: 01/01/2023]
Abstract
Whether prostate cancer (PCa) may be preventable by dietary interventions can be assessed in randomized trials using intermediate biomarkers of cancer risk or progression. We investigated whether lycopene or green tea modify circulating insulin-like growth factor (IGF) peptides in men at increased risk of PCa. Participants (aged 50-69 years) in one centre in the UK wide PCa testing and treatment trial (ProtecT) with prostate specific antigen between 2.0 and 2.95 ng/ml or negative biopsies, were randomized to daily lycopene (n = 44 assigned 15 mg capsules/day; 44 assigned a lycopene-rich diet; 45 assigned placebo) and green tea (n = 45 assigned 600 mg/day epigallocatechin gallate; 45 assigned green tea drink; 43 assigned placebo) for 6 months. The interventions significantly elevated the primary outcomes, serum epigallocatechin gallate and lycopene at 6 months of follow-up. We report here an exploratory analysis in which serum IGF-I, IGF-II, IGF binding protein (BP)-2 and IGFBP-3 were measured at baseline and 6 months of postintervention. A total of 133 men were randomized (34% of eligible men approached) and 130 had follow-up IGF peptides (98%). In intention-to-treat analyses, there was only weak evidence that lycopene or green tea influenced some aspects of serum IGF-I, IGF-II, IGFBP-2 or IGFBP-3. In men randomized to lycopene supplements, IGFBP-2 was nonsignificantly (50.9 ng/ml; 95% confidence interval: -51.2-152.9, P = 0.3) higher in comparison to placebo, whereas in men randomized to green tea supplements, IGFBP-3 was nonsignificantly (205.2 ng/ml; 95% confidence interval: -583.3-172.9, P = 0.3) lower than with placebo. In this small, pilot randomized controlled trial, there was little evidence that lycopene or green tea interventions influenced serum levels of IGF-I, IGF-II, IGFBBP-3 and IGFBP-2. However, the effects were imprecisely estimates and some observed trends may justify larger trials.
Collapse
Affiliation(s)
- Kalina M. Biernacka
- IGFs & Metabolic Endocrinology Group, Translational Health Sciences, Bristol Medical School, Southmead Hospital
- National Institute for Health Research (NIHR) Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol
| | - Jeff M.P. Holly
- IGFs & Metabolic Endocrinology Group, Translational Health Sciences, Bristol Medical School, Southmead Hospital
| | - Richard M. Martin
- National Institute for Health Research (NIHR) Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol
- Population Health Sciences, Bristol Medical School, University of Bristol
| | - Aleksandra Frankow
- IGFs & Metabolic Endocrinology Group, Translational Health Sciences, Bristol Medical School, Southmead Hospital
- National Institute for Health Research (NIHR) Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol
| | - Caroline J. Bull
- IGFs & Metabolic Endocrinology Group, Translational Health Sciences, Bristol Medical School, Southmead Hospital
- Population Health Sciences, Bristol Medical School, University of Bristol
| | - Freddie C. Hamdy
- Nuffield Department of Surgery, University of Oxford
- Faculty of Medical Science, John Radcliffe Hospital, Oxford
| | - Jenny L. Donovan
- Population Health Sciences, Bristol Medical School, University of Bristol
| | - David E. Neal
- Department of Oncology, Addenbrooke’s Hospital, University of Cambridge
- Cancer Research UK Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK
| | - Chris Metcalfe
- Population Health Sciences, Bristol Medical School, University of Bristol
- Bristol Randomised Trials Collaboration, School of Social and Community Medicine, Bristol
| | - Athene Lane
- National Institute for Health Research (NIHR) Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol
- Population Health Sciences, Bristol Medical School, University of Bristol
| |
Collapse
|
3
|
Travis RC, Appleby PN, Martin RM, Holly JM, Albanes D, Black A, Bueno-de-Mesquita H, Chan JM, Chen C, Chirlaque MD, Cook MB, Deschasaux M, Donovan JL, Ferrucci L, Galan P, Giles GG, Giovannucci EL, Gunter MJ, Habel LA, Hamdy FC, Helzlsouer KJ, Hercberg S, Hoover RN, Janssen JA, Kaaks R, Kubo T, Le Marchand L, Metter EJ, Mikami K, Morris JK, Neal DE, Neuhouser ML, Ozasa K, Palli D, Platz EA, Pollak M, Price AJ, Roobol MJ, Schaefer C, Schenk JM, Severi G, Stampfer MJ, Stattin P, Tamakoshi A, Tangen CM, Touvier M, Wald NJ, Weiss NS, Ziegler RG, Key TJ, Allen NE. A Meta-analysis of Individual Participant Data Reveals an Association between Circulating Levels of IGF-I and Prostate Cancer Risk. Cancer Res 2016; 76:2288-2300. [PMID: 26921328 PMCID: PMC4873385 DOI: 10.1158/0008-5472.can-15-1551] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 12/22/2015] [Indexed: 11/16/2022]
Abstract
The role of insulin-like growth factors (IGF) in prostate cancer development is not fully understood. To investigate the association between circulating concentrations of IGFs (IGF-I, IGF-II, IGFBP-1, IGFBP-2, and IGFBP-3) and prostate cancer risk, we pooled individual participant data from 17 prospective and two cross-sectional studies, including up to 10,554 prostate cancer cases and 13,618 control participants. Conditional logistic regression was used to estimate the ORs for prostate cancer based on the study-specific fifth of each analyte. Overall, IGF-I, IGF-II, IGFBP-2, and IGFBP-3 concentrations were positively associated with prostate cancer risk (Ptrend all ≤ 0.005), and IGFBP-1 was inversely associated weakly with risk (Ptrend = 0.05). However, heterogeneity between the prospective and cross-sectional studies was evident (Pheterogeneity = 0.03), unless the analyses were restricted to prospective studies (with the exception of IGF-II, Pheterogeneity = 0.02). For prospective studies, the OR for men in the highest versus the lowest fifth of each analyte was 1.29 (95% confidence interval, 1.16-1.43) for IGF-I, 0.81 (0.68-0.96) for IGFBP-1, and 1.25 (1.12-1.40) for IGFBP-3. These associations did not differ significantly by time-to-diagnosis or tumor stage or grade. After mutual adjustment for each of the other analytes, only IGF-I remained associated with risk. Our collaborative study represents the largest pooled analysis of the relationship between prostate cancer risk and circulating concentrations of IGF-I, providing strong evidence that IGF-I is highly likely to be involved in prostate cancer development. Cancer Res; 76(8); 2288-300. ©2016 AACR.
Collapse
Affiliation(s)
- Ruth C. Travis
- Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Paul N. Appleby
- Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Richard M. Martin
- School of Social and Community Medicine, University of Bristol, Bristol, UK
- Medical Research Council/University of Bristol Integrative Epidemiology Unit, University of Bristol, and National Institute for Health Research, Bristol Biomedical Research Unit in Nutrition, Bristol, UK
| | - Jeff M.P. Holly
- School of Clinical Science, Faculty of Medicine, University of Bristol, Bristol, UK
| | - Demetrius Albanes
- Division of Cancer Epidemiology and Genetics, U.S. National Cancer Institute, Bethesda, MD, USA
| | - Amanda Black
- Division of Cancer Epidemiology and Genetics, U.S. National Cancer Institute, Bethesda, MD, USA
| | - H.B(as). Bueno-de-Mesquita
- Dt. for Determinants of Chronic Diseases, National Institute for Public Health and the Environment (RIVM), Bilthoven, and Dt. of Gastroenterology and Hepatology, University Medical Centre, Utrecht, The Netherlands, and Dt. of Social & Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - June M. Chan
- Departments of Epidemiology & Biostatistics and Urology, University of California San Francisco, CA, USA
| | - Chu Chen
- Division of Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Maria-Dolores Chirlaque
- Department of Epidemiology, Murcia Regional Health Council, IMIB-Arrixaca, and CIBER Epidemiología y Salud Pública, Spain
| | - Michael B. Cook
- Division of Cancer Epidemiology and Genetics, U.S. National Cancer Institute, Bethesda, MD, USA
| | - Mélanie Deschasaux
- Sorbonne Paris Cité Epidemiology and Biostatistics Research Center, Nutritional Epidemiology Research Team, Inserm U1153, Inra U1125, Cnam, University Paris 13, University Paris 5, University Paris 7, F-93017, Bobigny, France
| | - Jenny L. Donovan
- School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - Luigi Ferrucci
- Intramural Research Program, National Institute on Aging, Baltimore, MD, USA
| | - Pilar Galan
- Sorbonne Paris Cité Epidemiology and Biostatistics Research Center, Nutritional Epidemiology Research Team, Inserm U1153, Inra U1125, Cnam, University Paris 13, University Paris 5, University Paris 7, F-93017, Bobigny, France
| | - Graham G. Giles
- Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, and Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Victoria, Australia
| | - Edward L. Giovannucci
- Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA
- Department of Nutrition and Department of Medicine, Harvard School of Public Health, Boston, MA, USA
| | - Marc J. Gunter
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - Laurel A. Habel
- Division of Research, Kaiser Permanente, Northern California, Oakland, California, USA
| | | | - Kathy J. Helzlsouer
- The Prevention and Research Center, Mercy Medical Center, Baltimore, MD, USA
| | - Serge Hercberg
- Sorbonne Paris Cité Epidemiology and Biostatistics Research Center, Nutritional Epidemiology Research Team, Inserm U1153, Inra U1125, Cnam, University Paris 13, University Paris 5, University Paris 7, F-93017, Bobigny, France
| | - Robert N. Hoover
- Division of Cancer Epidemiology and Genetics, U.S. National Cancer Institute, Bethesda, MD, USA
| | | | - Rudolf Kaaks
- Division of Cancer Epidemiology, German Cancer Research Centre, Heidelberg, Germany
| | - Tatsuhiko Kubo
- University of Occupational and Environmental Health, Kitakyushu, Japan
| | | | - E. Jeffrey Metter
- Intramural Research Program, National Institute on Aging, Baltimore, MD, USA
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN
| | - Kazuya Mikami
- Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Joan K. Morris
- Wolfson Institute of Preventive Medicine, Queen Mary University of London, Charterhouse Square, London, UK
| | | | - Marian L. Neuhouser
- Division of Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Kotaro Ozasa
- Radiation Effects Research Foundation, Hiroshima, Japan
| | - Domenico Palli
- Molecular and Nutritional Epidemiology Unit, Cancer Research and Prevention Institute – ISPO, Florence, Italy
| | - Elizabeth A. Platz
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Michael Pollak
- Departments of Medicine and Oncology, McGill University, Montreal, QC, Canada
| | - Alison J. Price
- Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | | | - Catherine Schaefer
- Division of Research, Kaiser Permanente, Northern California, Oakland, California, USA
| | - Jeannette M. Schenk
- Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Epidemiology, University of Washington, Seattle, WA, USA
| | - Gianluca Severi
- Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, and Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Victoria, Australia
- Human Genetics Foundation, Torino, Italy
| | - Meir J. Stampfer
- Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Pär Stattin
- Department of Surgical and Perioperative Sciences, Urology and Andrology, Umeå University, Umeå, Sweden
| | - Akiko Tamakoshi
- Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Catherine M. Tangen
- SWOG Statistical Center, Fred Hutchinson Cancer Research Center, and Department of Biostatistics, University of Washington, Seattle, WA, USA
| | - Mathilde Touvier
- Sorbonne Paris Cité Epidemiology and Biostatistics Research Center, Nutritional Epidemiology Research Team, Inserm U1153, Inra U1125, Cnam, University Paris 13, University Paris 5, University Paris 7, F-93017, Bobigny, France
| | | | | | - Regina G. Ziegler
- Division of Cancer Epidemiology and Genetics, U.S. National Cancer Institute, Bethesda, MD, USA
| | - Timothy J. Key
- Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Naomi E. Allen
- Clinical Trials Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| |
Collapse
|
4
|
Bann D, Holly JM, Lashen H, Hardy R, Adams J, Kuh D, Ong KK, Ben‐Shlomo Y. Changes in insulin-like growth factor-I and -II associated with fat but not lean mass in early old age. Obesity (Silver Spring) 2015; 23:692-8. [PMID: 25645314 PMCID: PMC4737231 DOI: 10.1002/oby.21002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 11/18/2014] [Indexed: 12/15/2022]
Abstract
OBJECTIVE To test the hypothesis that insulin-like growth factors-I and II (IGF-I and II) decline during late midlife and that greater declines are related to higher fat mass and lower lean mass. METHODS A total of 1,542 men and women in a British birth cohort study had IGF-I and II measured by immunoassay of blood samples at age 53 and/or 60-64 years. Fat mass, android:gynoid fat ratio, and appendicular lean mass were measured at 60-64 years using dual-energy X-ray absorptiometry (DXA). Associations between changes in IGF-I or II and body composition outcomes were examined using conditional change linear regression models. RESULTS Mean IGF-I and IGF-II concentrations were lower at 60-64 than at 53 years, by 12.8% for IGF-I and by 12.5% for IGF-II. Larger declines in either IGF-I or II were associated with higher fat mass at 60-64 years. Although higher IGF-I at 53 years was associated with higher lean mass, there was little evidence linking changes in IGF-I or II to lean mass. CONCLUSIONS The findings suggest that IGF-I and II concentrations decline with age, and greater declines are associated with higher fat mass levels. These results provide some evidence for the suggested roles of IGF-I and II in regulating fat mass but not lean mass in older age.
Collapse
Affiliation(s)
- David Bann
- MRC Unit for Lifelong Health and Ageing, University College LondonLondonUK
| | - Jeff M.P. Holly
- IGFs and Metabolic EndocrinologySchool of Clinical Sciences, Bristol UniversityBristolUK
| | - Hany Lashen
- Department of Human MetabolismThe University of SheffieldSheffieldUK
| | - Rebecca Hardy
- MRC Unit for Lifelong Health and Ageing, University College LondonLondonUK
| | - Judith Adams
- Department of RadiologyCentral Manchester University Hospital NHS Foundation Trust, Manchester Academic Health Science CentreOxford RoadManchesterUK
| | - Diana Kuh
- MRC Unit for Lifelong Health and Ageing, University College LondonLondonUK
| | - Ken K. Ong
- MRC Epidemiology UnitUniversity of CambridgeCambridgeUK
| | - Yoav Ben‐Shlomo
- School of Social and Community MedicineBristol UniversityBristolUK
| |
Collapse
|
5
|
Hale LJ, Welsh GI, Perks CM, Hurcombe JA, Moore S, Hers I, Saleem MA, Mathieson PW, Murphy AJ, Jeansson M, Holly JM, Hardouin SN, Coward RJ. Insulin-like growth factor-II is produced by, signals to and is an important survival factor for the mature podocyte in man and mouse. J Pathol 2013; 230:95-106. [PMID: 23299523 DOI: 10.1002/path.4165] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 12/03/2012] [Accepted: 12/26/2012] [Indexed: 01/10/2023]
Abstract
Podocytes are crucial for preventing the passage of albumin into the urine and, when lost, are associated with the development of albuminuria, renal failure and cardiovascular disease. Podocytes have limited capacity to regenerate, therefore pro-survival mechanisms are critically important. Insulin-like growth factor-II (IGF-II) is a potent survival and growth factor; however, its major function is thought to be in prenatal development, when circulating levels are high. IGF-II has only previously been reported to continue to be expressed in discrete regions of the brain into adulthood in rodents, with systemic levels being undetectable. Using conditionally immortalized human and ex vivo adult mouse cells of the glomerulus, we demonstrated the podocyte to be the major glomerular source and target of IGF-II; it signals to this cell via the IGF-I receptor via the PI3 kinase and MAPK pathways. Functionally, a reduction in IGF signalling causes podocyte cell death in vitro and glomerular disease in vivo in an aged IGF-II transgenic mouse that produces approximately 60% of IGF-II due to a lack of the P2 promoter of this gene. Collectively, this work reveals the fundamental importance of IGF-II in the mature podocyte for glomerular health across mammalian species.
Collapse
Affiliation(s)
- L J Hale
- Academic and Children's Renal Unit, University of Bristol, Learning and Research, Southmead Hospital, Bristol, BS10 5NB, UK
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Martin RM, Holly JM, Gunnell D. Milk and Linear Growth: Programming of the IGF-I Axis and Implication for Health in Adulthood. Milk and Milk Products in Human Nutrition 2011; 67:79-97. [DOI: 10.1159/000325577] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
7
|
Foulstone EJ, Holly JM, Zeng L, Winters ZE, Perks CM. Insulin-like growth factor binding protein-2 alters the sensitivity of breast cancer cells to chemotherapy. Breast Cancer Res 2010. [PMCID: PMC2875584 DOI: 10.1186/bcr2519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
8
|
|
9
|
Foulstone EJ, Savage PB, Crown AL, Holly JM, Stewart CE. Adaptations of the IGF system during malignancy: human skeletal muscle versus the systemic environment. Horm Metab Res 2003; 35:667-74. [PMID: 14710345 DOI: 10.1055/s-2004-814159] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Presented in this study are data derived from a unique cohort of patients both with and without cancer, for whom we not only have serum samples, allowing us to investigate systemic factors impacting on skeletal muscle maintenance, but also primary skeletal muscle cultures giving us a model to mimic the in vivo muscle milieu. Possible local effects of autocrine/paracrine and endocrine IGF system components impacting on myoblast growth and differentiation could therefore be assessed. We report for the first time that the decrease in myoblast stem cell numbers seen with normal aging is lost in cancer patients. We further report that serum IGF-I, IGF-II and IGFBP-3 all show positive correlations with myoblast retrieval in control patients, but that with the exception of IGFBP-3 these correlations are lost in malignancy. Indeed IGF-II switches to a negative correlation with myotube formation in malignancy. Furthermore we provide initial evidence to suggest that there is an apparent altered regulation of local IGFBP-3 production during malignancy which may enable satellite cell proliferation, stem cell infiltration or both. Finally we show the importance of investigations not only monitoring the systemic impact of serum factors on skeletal muscle responses but also critically assessing the role that locally produced muscle IGFBP-3 may have on the systemic environment.
Collapse
Affiliation(s)
- E J Foulstone
- Division of Surgery, University of Bristol, Bristol Royal Infirmary, Bristol, BS2 8HW, England.
| | | | | | | | | |
Collapse
|
10
|
Affiliation(s)
- D Gunnell
- Department of Social Medicine, Canynge Hall, University of Bristol, Whiteladies Road, Bristol BS8 2PR, United Kingdom.
| | | | | | | | | | | |
Collapse
|
11
|
Justová V, Lacinová Z, Melenovský V, Marek J, Holly JM, Hass T. The changes of IGF binding proteins after rhGH administration to patients totally dependent on parenteral nutrition. Growth Horm IGF Res 2001; 11:407-415. [PMID: 11914029 DOI: 10.1054/ghir.2001.0257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The objective was to study the effect of recombinant human growth hormone (rhGH) administration to patients with chronic malnutrition maintained on total parenteral nutrition (TPN) on the levels of insulin-like growth factor-I (IGF-I) and IGF binding proteins (IGFBPs) during a double-blind trial. After 1 week of TPN the patients were randomized into group I (placebo) or group II (rhGH). Samples were collected on the first day (start of the TPN) to measure basal values, the seventh day to study the effect of TPN and the 10th, 14th and 21st days to evaluate the rhGH effect. Basal laboratory evaluation, nutritional status and glucose tolerance were assessed using standard laboratory techniques. Radioimmunoassays were used to analyse IGF-I, free IGF-I (fIGF-I) and IGFBP1-3. Electrophoresis with Western ligand blotting and Western immunoblotting was applied to find the pattern of IGFBPs. TPN had no effect on the circulating IGF-I concentration and the pattern of IGFBPs present in the studied groups of patients. The rhGH administration led to significant increases of IGF-I, total IGFBP-3, glycosylated IGFBP-3 (39, 42 kDa) and the 29 kDa fragment of IGFBP-3 and the decrease of IGFBP-2 during the trial (P<0.05). The mean levels of IGFBP-1, fIGF-I and the parameters of nutritional status in group II during the trial were not significantly influenced by rhGH. However, it has been found that IGFBP-1 and fIGF-I levels were correlated with the levels of the weekly nitrogen balance of each patient in group II at the end of the trial. In spite of the significant changes of IGF-I, IGFBP-2, total IGFBP-3 and IGFBP-3 (29 kDa proteolytic fragment) after rhGH administration to patients with malnutrition, maintained on parenteral nutrition, the increase of nitrogen balance was seen only in patients who decreased their IGFBP-1 and increased bioavailable IGF-I as reflected by measurement of fIGF-I. The levels of IGFBP-1 may provide a useful marker of IGF-I bioavailability in monitoring the efficiency of the rhGH therapy in malnourished patients.
Collapse
Affiliation(s)
- V Justová
- Third Medical Department of Charles University, Prague, Czech Republic.
| | | | | | | | | | | |
Collapse
|
12
|
Foulstone EJ, Meadows KA, Holly JM, Stewart CE. Insulin-like growth factors (IGF-I and IGF-II) inhibit C2 skeletal myoblast differentiation and enhance TNF alpha-induced apoptosis. J Cell Physiol 2001; 189:207-15. [PMID: 11598906 DOI: 10.1002/jcp.10017] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
IGF-I and IGF-II are thought to be unique in their ability to promote muscle cell differentiation. Murine C2 myoblasts differentiate when placed into low serum media (LSM), accompanied by increased IGF-II and IGF binding protein-5 (IGFBP-5) production. Addition of 20 ng/ml TNF alpha on transfer into LSM blocked differentiation, IGF-II and IGFBP-5 secretion and induced apoptosis. We, therefore, wished to assess whether IGFs could protect against the effects of TNF alpha. Neither inhibition of differentiation or induction of apoptosis was rescued by co-incubation with IGF-I or IGF-II. A lower dose of TNF alpha (1 ng/ml) while not inducing apoptosis still inhibited myoblast differentiation by 56% +/- 12, (P < 0.001), indicating that induction of apoptosis is not the sole mechanism by which TNF alpha inhibits myoblast differentiation. Addition of IGF-I or IGF-II alone reduced differentiation by 49% +/- 15 and 33% +/- 20, respectively, (P < 0.001), although neither induced apoptosis. For muscle cells to differentiate, they must arrest in G0. We established that addition of IGF-I, IGF-II or TNF alpha to the myoblasts promoted proliferation. The myoblasts could not exit the cell cycle as efficiently as controls and differentiation was thus reduced. Unexpectedly, co-incubation of IGF-I or IGF-II with 1 ng/ml TNF alpha enhanced the inhibition of differentiation and induced apoptosis. In the absence of apoptosis we show an association between IGF-induced inhibition of differentiation and increased IGFBP-5 secretion. These results indicate that the effects of the IGFs on muscle may depend on the cytokine environment. In the absence of TNF alpha, the IGFs delay differentiation and promote myoblast proliferation whereas in the presence of TNF alpha the IGFs induce apoptosis.
Collapse
Affiliation(s)
- E J Foulstone
- Division of Surgery, University of Bristol, Bristol Royal Infirmary, Bristol, UK.
| | | | | | | |
Collapse
|
13
|
Crowne EC, Samra JS, Cheetham T, Acerini CL, Watts A, Holly JM, Dunger DB. The role of IGF-binding proteins in mediating the effects of recombinant human IGF-I on insulin requirements in type 1 diabetes mellitus. J Clin Endocrinol Metab 2001; 86:3686-91. [PMID: 11502796 DOI: 10.1210/jcem.86.8.7722] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To determine the role of IGF-binding proteins in mediating the direct effects of recombinant human IGF-I on insulin requirements in type 1(insulin-dependent) diabetes mellitus, overnight changes in IGF-I, IGF-II, and IGF-binding protein-1, -2, and -3, collected under euglycemic conditions, were compared in nine subjects after double blind, randomized, sc administration of recombinant human IGF-I (40 microg/kg) or placebo at 1800 h. On both nights a somatostatin analog infusion (300 ng/kg x h) suppressed endogenous GH production, and three timed discrete GH pulses (total, 0.029 IU/kg x night) ensured identical GH levels. After recombinant human IGF-I administration, IGF-I levels and the IGF-I/IGF-binding protein-3 ratio increased [mean +/- SEM:IGF-I, 401 +/- 22 ng/ml; placebo, 256 +/- 20 ng/ml (P = 0.0002); IGF-I, 0.108 +/- 0.006; placebo, 0.074 +/- 0.004 (P = 0.0003), respectively], and insulin requirements decreased (IGF-I, 0.12 +/- 0.03; placebo, 0.23 +/- 0.03 U/kg x min; P = 0.008). The normal within-individual inverse relationships between insulin and IGF-binding protein-1 levels were observed (lag time 2 h: r = -0.34; P < 0.01). Yet despite reduced free insulin levels (8.5 +/- 1.5; placebo, 12.2 +/- 1.2 mU/liter; P = 0.03), IGF-binding protein-1 levels were reduced after recombinant human IGF-I administration (53.7 +/- 6.8; placebo, 82.2 +/- 11.8 ng/ml; P = 0.008). The largest reductions in free insulin levels after recombinant human IGF-I and thus putative improvement in insulin sensitivity occurred in subjects with the smallest increase in the plasma IGF-I/IGF-binding protein-3 ratio (r = 0.7; P = 0.03). Taken together, these data are consistent with the hypothesis that transcapillary movement of IGF-I (perhaps mediated by IGF-binding protein-1), out of the circulation facilitates altered insulin sensitivity. These data have important implications for risk-benefit assessment of recombinant human IGF-I therapy in type 1 diabetes mellitus.
Collapse
Affiliation(s)
- E C Crowne
- Bristol Royal Hospital for Sick Children, Bristol, United Kingdom BS2 8BJ
| | | | | | | | | | | | | |
Collapse
|
14
|
Helle SI, Geisler S, Aas T, Paulsen T, Holly JM, Lønning PE. Plasma insulin-like growth factor binding protein-3 proteolysis is increased in primary breast cancer. Br J Cancer 2001; 85:74-7. [PMID: 11437405 PMCID: PMC2363920 DOI: 10.1054/bjoc.2001.1860] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fasting blood samples were obtained before definitive surgery or biopsy in 128 patients referred to the department of surgery with suspected or manifest breast cancer. Insulin-like growth factor (IGF)-I, IGF-II and free IGF-I were measured by radioimmunoassay/immunoradiometric assay, while IGFBP-3 proteolysis was evaluated by Western immunoblot. 12 patients had ductal carcinoma in situ benign conditions, while staging revealed metastatic disease in 15 of 16 patients with invasive cancers. IGFBP-3 proteolysis above the normal range was recorded in 19 patients with invasive cancers, but in none of the patients suffering from DCIS/benign conditions. Increased IGFBP-3 proteolysis was most frequently recorded in patients harbouring large tumours and metastatic disease (Stage I: 0/19, 0%; Stage II: 3/45, 7%, Stage III: 9/37, 24%, and Stage IV: 7/15, 47%). IGFBP-3 proteolysis was significantly higher in Stage III (P =0.01) and IV (P< 0.001) patients compared to the other stage groups (P = 0.001). IGF-I and IGF-II correlated negatively to IGFBP-3 proteolysis and age. Plasma levels of IGF-I and -II were significantly lower in patients with elevated IGFBP-3 proteolysis compared to those within the normal range. Our findings reveal alterations in the IGF-system among a substantial number of patients with large primary breast cancers.
Collapse
Affiliation(s)
- S I Helle
- Department of Oncology, Haukelland University Hospital, Bergen, Norway
| | | | | | | | | | | |
Collapse
|
15
|
Helle SI, Geisler J, Anker GB, Leirvaag B, Holly JM, Lønning PE. Alterations in the insulin-like growth factor system during treatment with diethylstilboestrol in patients with metastatic breast cancer. Br J Cancer 2001; 85:147-51. [PMID: 11461068 PMCID: PMC2364048 DOI: 10.1054/bjoc.2001.1871] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Alterations in the insulin-like growth factor (IGF)-system were evaluated in 16 patients treated with diethylstilboestrol 5 mg 3 times daily. Fasting blood samples were obtained before treatment and after 2 weeks, 1 month and/or 2-3 months on therapy. Insulin-like growth factor (IGF)-I, IGF-II, free IGF-I, IGF-binding protein (IGFBP)-1, IGFBP-2 and IGFBP-3 were measured by radioimmuno-/immunoradiometric-assays. All samples were subjected to Western ligand blotting as well as immunoblotting for IGFBP-3. We observed a significant decrease (percentage of pretreatment levels with 95 confidence intervals of the mean) in IGF-I [2 weeks 63% (49-79); 1 month 56% (44-73); 2-3 months 66% (53-82)], IGF-II [2 weeks 67% (56-80); 1 month 60% (52-68); 2-3 months 64% (55-75)], free IGF-I [2 weeks 29% (19-42); 1 month 25% (18-36); 2-3 months 31% (21-46)], IGFBP-2 [2 weeks 53% (18-156); 1 month 69% (61-78); 2-3 months 66% (57-78)], IGFBP-3 [2 weeks 74% (63-85); 1 month 69% (62-76); 2-3 months 71% (63-80)], as well as IGFBP-3 protease activity [2 weeks 71% (54-95); 1 month 78% (64-94); 2-3 months 71% (54-93)]. Contrary, the plasma levels (percentage of pretreatment levels with 95 confidence intervals of the mean) of IGFBP-1 [2 weeks 250% (127-495); 1 month 173% (138-542); 2-3 months 273% (146-510)] and IGFBP-4 [2 weeks 146% (112-192); 1 month 140% (116-169); 2-3 months 150% (114-198)] increased significantly. While this study confirms previous observations during treatment with oral oestrogens in substitution doses, the reduction in plasma IGF-II, free IGF-I, IGFBP-2 and -3 are all novel findings. A profound decrease in free IGF-I suggests a reduced bioavailability of IGFs from plasma to the tissues. These observations may be of significance to understand the mechanisms of the antitumour effect of diethylstilboestrol in pharmacological doses.
Collapse
Affiliation(s)
- S I Helle
- Department of Oncology, Haukeland University Hospital, Bergen, N-5021, Norway
| | | | | | | | | | | |
Collapse
|
16
|
Helle SI, Ueland T, Ekse D, Frøland SS, Holly JM, Lønning PE, Aukrust P. The insulin-like growth factor system in human immunodeficiency virus infection: relations to immunological parameters, disease progression, and antiretroviral therapy. J Clin Endocrinol Metab 2001; 86:227-33. [PMID: 11232005 DOI: 10.1210/jcem.86.1.7135] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Endocrine dysfunctions have previously been reported in human immunodeficiency virus (HIV) infection. In this study we evaluated the relation of immunological parameters, virus load, clinical stage, and wasting to several parameters of the insulin-like growth factor (IGF) system in 76 patients with HIV infection, of whom 37 had developed acquired immune deficiency syndrome (AIDS). A subgroup of 26 untreated patients was followed during longitudinal testing, while the effects of antiretroviral therapy were evaluated in 34 patients (nucleoside analogs in 9, nucleoside analogs in combination with protease inhibitors in 25). Twenty healthy sex- and age-matched controls were analyzed for comparison. IGF-II was decreased (P = 0.03) and IGF-binding protein-2 (IGFBP-2) and IGFBP-3 protease activity were increased (P < 0.001) in AIDS patients compared with other HIV-infected individuals and controls. Plasma levels of IGFBP-2 and IGFBP-3 protease activity correlated positively to virus load (P < 0.001) and tumor necrosis factor-alpha (P < 0.025) and negatively to CD4(+) and CD8(+) cell counts (P < 0.001). AIDS patients with wasting (n = 13) had lower IGF-II levels (P = 0.001) and higher IGFBP-2 levels (P = 0.001) than other AIDS patients. Although no significant change in any of the IGF-parameters was observed in patients during antiretroviral therapy, patients with elevated IGFBP-3 protease activity before therapy (5 of 34) all had a decrease during treatment. During longitudinal testing in patients followed without antiretroviral therapy, disease progression was associated with increases in IGFBP-3 protease activity and IGFBP-2 levels. Our results reveal several alterations in the IGF system during HIV infection with decreased IGF-II levels, increased concentration of IGFBP-2, and an increased IGFBP-3 protease activity in advanced disease.
Collapse
Affiliation(s)
- S I Helle
- Department of Oncology, Haukeland University Hospital, N-5021 Bergen, Norway
| | | | | | | | | | | | | |
Collapse
|
17
|
Crown AL, He XL, Holly JM, Lightman SL, Stewart CE. Characterisation of the IGF system in a primary adult human skeletal muscle cell model, and comparison of the effects of insulin and IGF-I on protein metabolism. J Endocrinol 2000; 167:403-15. [PMID: 11115767 DOI: 10.1677/joe.0.1670403] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In an attempt to address the complex and clinically challenging question of the causes of muscle wasting in patients with cachexia, we have developed a primary adult human skeletal muscle cell model. The cultured cells were characterised by immunocytochemistry using antibodies to the myofibrillar protein constituents desmin and titin. Myotube formation was confirmed biochemically by a fourfold increase in the activity of the muscle-specific enzyme creatinine kinase, and myoblast withdrawal from the cell cycle, which is essential for terminal differentiation, was associated with progressive retinoblastoma protein dephosphorylation. Having successfully confirmed the phenotype of these adult human muscle cells, we assessed their interaction with the insulin-like growth factor (IGF) system. IGF-I is known to stimulate myoblast survival, proliferation and differentiation in cell lines, and, like insulin, is a potent anabolic agent in the regulation of protein metabolism. We have shown that IGF-I stimulated both replication and differentiation of myoblasts, whilst fibroblast growth factor-2 stimulated replication but inhibited differentiation. Examining the IGF system during the process of terminal differentiation, we found that both myoblasts and myotubes expressed insulin, IGF-I and insulin-IGF-I hybrid receptors, with the levels of all three receptor types increasing on differentiation. The cells also produced a wide range of IGF binding proteins (IGFBPs) including IGFBP-2, IGFBP-4 and abundant IGFBP-3, which has not been shown to be produced by any other skeletal muscle cell line examined to date. Both insulin and IGF-I had anabolic effects on myotube protein metabolism at physiological concentrations. Insulin was more potent than IGF-I: use of the IGF analogue long R(3)IGF-I demonstrated that the effects of exogenous IGF-I on protein metabolism were not affected by the high levels of endogenous IGFBP production. In summary, we have developed and characterised a clinically relevant in vitro model with which to address the aetiology of muscle wasting associated with chronic catabolic conditions, and we anticipate that future work will enable the development of novel, effective therapeutic interventions.
Collapse
Affiliation(s)
- A L Crown
- Department of Medicine, University of Bristol, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK
| | | | | | | | | |
Collapse
|
18
|
Fowler CA, Perks CM, Newcomb PV, Savage PB, Farndon JR, Holly JM. Insulin-like growth factor binding protein-3 (IGFBP-3) potentiates paclitaxel-induced apoptosis in human breast cancer cells. Int J Cancer 2000. [PMID: 11054675 DOI: 10.1002/1097-0215(20001101)88:3<448::aid-ijc18>3.0.co;2-v] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Variability in response to chemotherapy is poorly understood. Paclitaxel-induced apoptosis was assessed in human Hs578T breast cancer cells, using the MTT assay, cell counting, morphological features and flow cytometry. Pre-dosing cells with non-glycosylated insulin-like growth factor binding protein-3 (ngIGFBP-3) had no effect on the cells per se but accentuated paclitaxel-induced apoptosis. The apoptotic pathway was further examined by measuring caspase-3 activity in cell lysates at time points over 48 hr after dosing with paclitaxel. Activity increased significantly, and Western immunoblots for caspase-3 in conditioned media showed that the inactive precursor decreased after incubation with paclitaxel. Endogenous production of IGFBP-3 by the cells after incubation with paclitaxel was evaluated using Western ligand blotting, specific IGFBP-3 immunoblotting and radioimmunoassay. Paclitaxel increased endogenous IGFBP-3, which was further increased if the cells had been pre-dosed with ngIGFBP-3. These findings suggest that IGFBP-3 may be an important modulator of paclitaxel-induced apoptosis.
Collapse
Affiliation(s)
- C A Fowler
- Department of Hospital Medicine, Bristol Royal Infirmary, United Kingdom.
| | | | | | | | | | | |
Collapse
|
19
|
Hollowood AD, Lai T, Perks CM, Newcomb PV, Alderson D, Holly JM. IGFBP-3 prolongs the p53 response and enhances apoptosis following UV irradiation. Int J Cancer 2000; 88:336-41. [PMID: 11054660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Neoplastic transformation is characterised by an imbalance in favour of cell growth over programmed cell death (apoptosis). The tumour-suppressor gene p53, responsible for maintaining cell-cycle control, is mutated in the majority of human cancers. Loss of function of the target genes of p53 are therefore important in tumourigenesis. One such target gene is the insulin-like growth factor binding protein-3 (IGFBP-3), an extracellular protein responsible for the carriage of IGF-I but which can act independently of IGF-I, inhibiting cell growth and enhancing apoptosis. Using the KYSE 190 oesophageal carcinoma cell line, we have demonstrated that IGFBP-3 alone has no effect on cell growth or cell survival. However, it significantly enhanced apoptosis, with a 67% increase in the pre-G1 peak on flow cytometry following UV irradiation. The increase in p53 was enhanced and prolonged when cells are stressed in the presence of IGFBP-3. These data suggest an autocrine/paracrine feedback loop exists between IGFBP-3 and p53, which may provide the social control necessary to maintain normal tissue homeostasis.
Collapse
Affiliation(s)
- A D Hollowood
- Division of Surgery, Bristol Royal Infirmary, United Kingdom
| | | | | | | | | | | |
Collapse
|
20
|
Perks CM, McCaig C, Holly JM. Differential insulin-like growth factor (IGF)-independent interactions of IGF binding protein-3 and IGF binding protein-5 on apoptosis in human breast cancer cells. Involvement of the mitochondria. J Cell Biochem 2000; 80:248-58. [PMID: 11074596 DOI: 10.1002/1097-4644(20010201)80:2<248::aid-jcb140>3.0.co;2-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have demonstrated previously in Hs578T cells that insulin-like growth factor binding protein (IGFBP)-3 can significantly accentuate ceramide (C2)-induced apoptosis, but has no effect on cell death induced by integrin detachment [using an arginine-glycine-aspartic acid (RGD)-containing peptide]. In contrast we found that IGFBP-5 could inhibit apoptosis induced by either C2 or integrin detachment. It is now clear that the mitochondria not only provide the energy required for cell viability, but can also play an important role during the commitment phase to apoptosis. We used a mitochondrial respiratory chain inhibitor, antimycin A, at both apoptotic and nonapoptotic doses to further investigate the IGF-independent actions of IGFBP-3 and IGFBP-5 on C2 and RGD-induced apoptosis in the Hs578T cells. Hs578T cells had one of three treatments. 1: They were incubated with increasing doses of antimycin A for 24 h. 2: They were coincubated with an apoptotic dose of either C2 or RGD together with a nonapoptotic dose of antimycin A for 24 h. 3: They were incubated with a binding protein (100 ng/ml) for 24 h followed by coincubation of the binding protein with an apoptotic dose of antimycin A for a further 24 h. Cell viability was assessed by trypan blue dye exclusion and MTT assay, and apoptosis was confirmed and measured by morphologic assessment and flow cytometry. We found that antimycin A initiated apoptosis at 10 micromol/L and above. We also demonstrated that a nonapoptotic dose of antimycin A (0.1 micromol/L) significantly inhibited C2-induced apoptosis, whereas it significantly accentuated RGD-induced cell death. In addition, we found that cell death induced by antimycin A can be accentuated by IGFBP-3 but is not affected by IGFBP-5. These data indicate that IGFBP-3 can directly enhance apoptosis triggered via the mitochondria; either directly by a mitochondrial inhibitor or by C2 (which we demonstrate to act via effects on the mitochondria in this model). IGFBP-5, however, appears to confer survival effects via a distinct pathway not involving the mitochondria.
Collapse
Affiliation(s)
- C M Perks
- Division of Surgery, Department of Hospital Medicine, Bristol Royal Infirmary, Bristol, BS2 8HW, United Kingdom
| | | | | |
Collapse
|
21
|
Affiliation(s)
- K P Jefferson
- Bristol Royal Infirmary, and Department of Clinical Science, Division of Surgery, University of Bristol, Bristol, UK.
| | | | | |
Collapse
|
22
|
Whellams EJ, Maile LA, Fernihough JK, Billingham ME, Holly JM. Alterations in insulin-like growth factor binding protein-3 proteolysis and complex formation in the arthritic joint. J Endocrinol 2000; 165:545-56. [PMID: 10828838 DOI: 10.1677/joe.0.1650545] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Increased concentrations of insulin-like growth factor (IGF) system components have previously been observed in rheumatoid arthritis (RA) and osteoarthritis (OA); however, disruption of the IGF axis and the implications for the disease process remain largely unaddressed. This study was undertaken to characterise the IGF binding protein (IGFBP)-3 proteolysis and complex formation systems in synovial fluid and to investigate changes in these systems in arthritic disease, and their impact on the availability of IGF. Western blotting or autoradiography of SDS gels was used to visualise IGFBP-3 or its proteolysis. IGF-I and IGFBP-3 concentrations were determined by radioimmunoassays and acid-labile subunit (ALS) was measured by ELISA. A shift in distribution of IGFBP-3 and IGF-I in RA and OA synovial fluids (RASynF, OASynF) and an associated increase in ALS suggested the presence of 150 kDa ternary complexes. IGFBP-3 proteolysis was decreased in RASynF and OASynF, but was apparent in size-fractionated fluid and resembled serum activity. The presence of serum-like inhibitors of IGFBP-3 proteolysis in RASynF was also demonstrated by the ability of this fluid, and 150 kDa fractions from its size fractionation, to inhibit IGFBP-3 proteolysis in the other synovial fluid. A marked disruption in the IGF system was observed, as considerably more IGF-I was retained in ternary complexes. We also classified the IGFBP-3 proteolysis system in synovial fluid and found it to be disturbed in RASynF and OASynF. These changes may be caused by an increased flux of circulatory proteins into synovial fluid, resulting from an inflammation-induced increase in vascular permeability. The net result in RA and OA would be a decrease in IGF availability in arthritic joints, and therefore loss of a potential anabolic stimulus. This disruption to the IGF axis would influence disease progression in RA and OA.
Collapse
Affiliation(s)
- E J Whellams
- University of Bristol, Department of Surgery, Division of Hospital Medicine, Bristol Royal Infirmary, Level 7, Bristol BS2 8HW, UK.
| | | | | | | | | |
Collapse
|
23
|
Meadows KA, Holly JM, Stewart CE. Tumor necrosis factor-alpha-induced apoptosis is associated with suppression of insulin-like growth factor binding protein-5 secretion in differentiating murine skeletal myoblasts. J Cell Physiol 2000; 183:330-7. [PMID: 10797307 DOI: 10.1002/(sici)1097-4652(200006)183:3<330::aid-jcp5>3.0.co;2-n] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Wasting of muscle and fat during cachexia exceeds that explained by reduced food intake alone. This wasting may result from an imbalanced cytokine environment, which could lead to increased protein catabolism. Supporting this, tumor necrosis factor-alpha (TNF-alpha) is raised in several animal models of cachectic muscle wasting. Therefore, we assessed the effects of TNF-alpha and its second messenger, ceramide, on the proliferation, differentiation, and survival of murine C2 skeletal myoblasts. Because insulin-like growth factor binding protein-5 (IGFBP-5) and insulin-like growth factor-II (IGF-II) are potent regulators of myoblast proliferation and differentiation, we monitored the ability of exogenous TNF-alpha to manipulate this system. Fibroblast growth factor (FGF) ceramide, or TNF-alpha suppressed differentiation of C2 cells compared with controls. All treatments suppressed IGF-II production but only TNF-alpha blocked IGFBP-5 secretion. TNF-alpha increased apoptotic cell death, which otherwise remained basal (low serum differentiation medium (LSM), FGF) or low (ceramide). Suppression of both IGFBP-5 and IGF-II secretion may explain why of all triggers tested, only TNF-alpha not only blocked differentiation, but also promoted cell death. This suggests a fundamental role of IGFBP-5 for maintaining muscle survival. Supporting this hypothesis, no increase in apoptosis was seen in IGFBP-5 cDNA tranfected C2 cells after TNF-alpha treatment. In summary, the IGF system is essential for maintaining skeletal muscle cell survival and differentiation, and its suppression by TNF-alpha is fundamental regarding muscle wasting, and may be associated in vivo with cancer cachexia.
Collapse
Affiliation(s)
- K A Meadows
- University Department of Surgery, Bristol Royal Infirmary, Bristol, England
| | | | | |
Collapse
|
24
|
Holly JM. Still more questions than answers: report on the 5th International Symposium on Insulin-like Growth Factors, Brighton, UK, 31 October-4 November 1999. Trends Endocrinol Metab 2000; 11:151-3. [PMID: 11228870 DOI: 10.1016/s1043-2760(00)00239-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The diverse backgrounds of the 550 scientists attending the 5th International Symposium on IGFs reflected the increasingly multidisciplinary approach to the field of insulin-like growth factor research. The presentations covered every aspect of the regulation, structure, physiology and pathology of not only IGF-I and IGF-II, but also their cell receptors and intracellular-signalling components, their specific-binding proteins (IGFBPs), as well as factors that bind to or modify these IGFBPs.
Collapse
Affiliation(s)
- J M Holly
- University Division of Surgery, Level 7, Bristol Royal Infirmary, Marlborough Street, Bristol, UK BS2 8HW.
| |
Collapse
|
25
|
Affiliation(s)
- J M Holly
- University Division of Surgery, Bristol Royal Infirmary, UK
| | | | | |
Collapse
|
26
|
Abstract
We have recently demonstrated that the presence or absence of IGFBP-3 protease activity in physiological fluids may not be determined simply by the presence or absence of specific enzymes but rather the presence of inhibitors. In addition, it appears that these inhibitors may not only be associated with the protease(s) but with the IGFBP-3 itself, protecting it from proteolytic cleavage. To provide further evidence for this mechanism of regulation we investigated whether IGFBP-3 protease activity could be unveiled in normal adult serum (NS) and whether the endogenous IGFBP-3 was protected from this activity. The addition of a range of concentrations of heparin, induced IGFBP-3 protease activity in NS. This was comparable to that seen in pregnancy serum (PS) by virtue of the fragmentation pattern and inhibitor profile. While the addition of zinc also revealed IGFBP-3 protease activity in NS the pattern of fragments differed to that seen in PS. Under both conditions, however, the endogenous IGFBP-3 was not proteolytically modified. These results demonstrate that IGFBP-3 protease activity is present in NS and can be activated, although the endogenous IGFBP-3 is relatively protected from such activity.
Collapse
Affiliation(s)
- L A Maile
- Division of Surgery, University of Bristol, Department of Hospital Medicine, Bristol Royal Infirmary, Bristol, BS2 8HW, UK.
| | | | | |
Collapse
|
27
|
Abstract
AIM To examine the hypothesis that the maternal insulin-like growth factor system may constrain fetal growth. METHODS A prospective observational study of maternal serum insulin-like growth factor binding protein-1 (IGFBP-1) and fetal growth was undertaken in neonates with birthweights below the 5th centile. They had been classified either as having fetal growth restriction (FGR) due to placental dysfunction (increased umbilical artery Doppler pulsatility index (PI); n = 25) or as being small for gestational age (SGA; normal umbilical artery PI, growth velocity and amniotic fluid; n = 27). Eighty nine controls had normal birthweights (5th-95th centile), umbilical artery PI, growth velocity, and amniotic fluid. IGFBP-1 was measured by radioimmunoassay. RESULTS Among the controls, there was no significant correlation between IGFBP-1 and birthweight after allowing for body mass index (BMI). Maternal BMI was high in FGR and after adjusting for this, IGFBP-1 was increased (109 ng/ml) compared with SGA babies (69 ng/ml) and controls (57 ng/ml) and correlated with the umbilical artery PI. CONCLUSIONS Maternal IGFBP-1 is probably not part of normal placental function. Its increase in FGR could be the cause or consequence of impaired placental perfusion, but high IGFBP-1 concentrations might further reduce the availability of maternal IGF-I to the placenta. This could worsen placental function and so adversely affect fetal growth.
Collapse
Affiliation(s)
- R P Holmes
- Fetal Medicine Research Unit, University of Bristol, St Michael's Hospital, Southwell Street, Bristol BS2 8EG, UK
| | | | | |
Collapse
|
28
|
Williams AC, Collard TJ, Perks CM, Newcomb P, Moorghen M, Holly JM, Paraskeva C. Increased p53-dependent apoptosis by the insulin-like growth factor binding protein IGFBP-3 in human colonic adenoma-derived cells. Cancer Res 2000; 60:22-7. [PMID: 10646845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
We investigated the expression of insulin-like growth factor binding protein 3 (IGFBP-3) in normal human colonic epithelium and whether IGFBP-3 is involved in the induction of apoptosis in colonic epithelial cells. A gradient of IGFBP-3 protein expression was observed within the normal colonic crypt, and increased IGFBP-3 expression was coincident with the region of increased differentiation and apoptosis. Treatment of human colonic tumor cell lines with IGFBP-3 alone was shown to have no effect on growth. However, an increase in p53-dependent apoptosis was observed in the presence of 100 ng/ml IGFBP-3 24 h after the induction of DNA damage by gamma-irradiation. These results suggest that IGFBP-3 enhances the p53-dependent apoptotic response of colorectal cells to DNA damage.
Collapse
Affiliation(s)
- A C Williams
- Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
29
|
Abstract
The IGFBP family comprises six proteins with high affinity for the IGFs and several lower affinity IGFBP-related proteins. Their production in the breast is controlled by hormones, other local regulators and in tumors relates to the estrogen receptor status. Their functional activity can also be affected by various post-translational modifications. The IGFs are generally present at levels far in excess of that required for maximal receptor stimulation, and the IGFBPs are critical regulators of cellular action. IGFBPs can affect cell function in an IGF-dependent or independent manner. IGF bioactivity locally in the breast is influenced not only by local tissue expression and regulation of IGFs, IGFBPs, and IGFBP proteases, but also by these factors delivered from the circulation. Changes in the balance of the components of the IGF system may lead to a disruption of tissue homeostasis.
Collapse
Affiliation(s)
- C M Perks
- Department of Hospital Medicine, Bristol Royal Infirmary, United Kingdom.
| | | |
Collapse
|
30
|
|
31
|
Abstract
We have demonstrated previously that insulin-like growth factor binding protein (IGFBP)-3 alone has little growth inhibitory effect on Hs578T human breast cancer cells, but that it can dramatically accentuate the apoptotic response to the physiological trigger, ceramide, in an IGF-independent manner. We have now studied the potential of other IGFBPs (1-6) to interact with apoptotic signalling pathways. Hs578T cells were preincubated with a binding protein (100 ng/ml) for 24 h, followed by co-incubation of the binding protein with an apoptotic dose of ceramide or RGD-containing peptide for a further 24 h. Apoptosis was assessed using flow cytometry, MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide; thiazolyl blue) assay and morphological assessment. Binding protein profiles were determined using ligand and immunoblotting techniques. Each of the IGFBPs (1-6) alone had no significant (P > 0. 05) growth inhibitory effects relative to control cells. In contrast to IGFBP-3, which significantly (P < 0.05) accentuated C2-induced apoptosis, IGFBP-1, -2, and -6 had no effect, whereas IGFBP-4 and -5 each caused marked (P < 0.01) inhibition of ceramide-induced programmed cell death. Apoptosis induced by RGD was also significantly (P < 0.05) reduced by IGFBP-5, whereas IGFBP-3 had no effect. These data provide evidence to suggest that individual IGFBPs have specific IGF-independent effects and act differentially on apoptotic signalling pathways.
Collapse
Affiliation(s)
- C M Perks
- Division of Surgery, Department of Hospital Medicine, Bristol Royal Infirmary, Bristol BS2 8HW, United Kingdom.
| | | | | | | | | |
Collapse
|
32
|
Mohamed-Ali V, Goodrick S, Bulmer K, Holly JM, Yudkin JS, Coppack SW. Production of soluble tumor necrosis factor receptors by human subcutaneous adipose tissue in vivo. Am J Physiol 1999; 277:E971-5. [PMID: 10600783 DOI: 10.1152/ajpendo.1999.277.6.e971] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
To investigate in vivo adipose tissue production of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and their soluble receptors: TNF receptor type I (sTNFR-I), TNF receptor type II (sTNFR-II), and IL-6 receptor (sIL-6R), we determined arteriovenous differences in their levels across abdominal subcutaneous adipose tissue in obese subjects. Subjects had a median (interquartile range) age of 44.5 (27-51.3) yr, body mass index (BMI) of 32.9 (26. 0-46.6) kg/m(2), and %body fat of 42.5 (28.5-51.2) %. Although there was not a significant difference in the arteriovenous concentrations of TNF-alpha (P = 0.073) or sTNFR-II (P = 0.18), the levels of sTNFR-I (P = 0.002) were higher in the vein compared with artery, suggesting adipose tissue production of this soluble receptor. There was a significant arteriovenous difference in IL-6 (P < 0.001) but not in its soluble receptor (P = 0.18). There was no relationship between TNF-alpha levels and adiposity indexes (r(s) = 0.12-0.22, P = not significant); however, levels of both its soluble receptor isomers correlated significantly with BMI and %body fat (sTNFR-I r(s) = 0.42-0.72, P < 0.001; sTNFR-II r(s) = 0.36-0.65, P < 0.05- <0. 001). IL-6 levels correlated significantly with both BMI and %body fat (r(s) = 0.51, P = 0.004, and r(s) = 0.63, P < 0.001), but sIL-6R did not. In conclusion, 1) soluble TNFR-I is produced by adipose tissue, and concentrations of both soluble isoforms correlate with the degree of adiposity, and 2) IL-6, but not its soluble receptor, is produced by adipose tissue and relates to adiposity.
Collapse
Affiliation(s)
- V Mohamed-Ali
- Centre for Diabetes and Cardiovascular Risk, University College London Medical School, London N19 3UA, United Kingdom.
| | | | | | | | | | | |
Collapse
|
33
|
Taylor AM, Thomson A, Bruce-Morgan C, Ahmed ML, Watts A, Harris D, Holly JM, Dunger DB. The relationship between insulin, IGF-I and weight gain in cystic fibrosis. Clin Endocrinol (Oxf) 1999; 51:659-65. [PMID: 10594529 DOI: 10.1046/j.1365-2265.1999.00858.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE In cystic fibrosis, reduced body mass is related to low levels of IGF-I and changes in the IGF binding proteins. Our aim was to determine whether these abnormalities are linked to pancreatic endocrine dysfunction. PATIENTS AND DESIGN We measured serum levels of insulin, IGF-I, IGFBP-I, IGFBP-3 and IGF bioactivity in 77 fasting subjects (43 male) mean age 9.6 years (range 2.99-17.98 years). Data were analysed with respect of body mass, puberty and stature and compared with control data established in the same laboratory. RESULTS The mean height standard deviation score (SDS (SD)) was -0.54 (0.97) and the body mass index SDS -0.24 (1.09). Both body mass index SDS (r = -0.40, P = 0.0003) and IGF-I SDS (r = - 0.32, P = 0.009) declined with age. Insulin levels were also low and correlated with IGF-I and IGFBP-3 (r = 0.42, P = 0.0004, and r = 0.45, P = 0.0002, respectively) whereas levels of IGFBP-I were inversely related to those of IGF-I and insulin (r = - 0.43, P = 0. 0004, r = - 0.52, P < 0.0001). IGF bioactivity was reduced and inversely related to IGFBP-I (r = - 0.31, P = 0.009). In multiple regression analysis, body mass index SDS was negatively related to age (P < 0.0001) and positively related to insulin and IGF-I (P = 0. 04, P = 0.03, respectively). Height SDS was correlated with IGF bioactivity (P = 0.003) and negatively with IGFBP-I (P = 0.01). CONCLUSIONS We conclude that progressive insulin deficiency may result in reduced IGF-I levels and IGF-bioactivity and may determine weight gain and statural growth in cystic fibrosis.
Collapse
Affiliation(s)
- A M Taylor
- University Department of Paediatrics, John Radcliffe Hospital, Oxford, UK
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Fernihough JK, Richmond RS, Carlson CS, Cherpes T, Holly JM, Loeser RF. Estrogen replacement therapy modulation of the insulin-like growth factor system in monkey knee joints. Arthritis Rheum 1999; 42:2103-11. [PMID: 10524681 DOI: 10.1002/1529-0131(199910)42:10<2103::aid-anr10>3.0.co;2-s] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Epidemiologic studies have suggested that estrogen replacement therapy may lower the risk of osteoarthritis in women, but the mechanism of this effect is unknown. Since estrogen acts in other tissues in part through regulation of the insulin-like growth factor (IGF) system as well as cytokines including interleukin-6 (IL-6), we determined whether estrogen replacement regulates the levels of these factors in synovial fluid (SF). METHODS Levels of IGF-1, IGF-2, IGF binding proteins (IGFBP) 1-3, and IL-6 were measured in SF samples obtained from 67 female adult cynomolgus monkeys that had been ovariectomized and treated for 30 months in 1 of 3 groups. Group 1 (n = 24) had no estrogen replacement (control), group 2 (n = 22) received estrogen (Premarin) at the human equivalent of 0.625 mg/day, and group 3 (n = 21) received estrogen at the same dose as group 2, plus progesterone (Provera) at the equivalent of 2.5 mg/day. RESULTS Compared with controls, estrogen-treated monkeys had 2-fold higher SF levels of IGF-1 (P < 0.001), 1.7-fold higher IGF-2 (P < 0.006), 5.9-fold higher IGFBP-1 (P < 0.02), and 2.5-fold higher IGFBP-3 (P < 0.001). Estrogen plus progesterone-treated monkeys had SF levels of IGF-1, IGF-2, IGFBP-1, and IGFBP-3 that were intermediate between the levels in the control and estrogen groups, except that the level of IGFBP-3 was significantly greater than that in the control group (P < 0.001). SF levels of IGFBP-2 and IL-6 did not differ by treatment group. Treatment group did not affect the serum levels of IGF-1 and IL-6, but IGF-2 and IGFBP-3 were increased by 1.6- and 1.8-fold, respectively, in the estrogen group (P < 0.001). There was no correlation between changes in serum and SF levels of IGF components, except for a weak correlation for IGFBP-3 levels from control (r = 0.464, P = 0.04) and estrogen-treated (r = 0.577, P = 0.008) animals. CONCLUSION This study demonstrates a significant effect of estrogen replacement on IGF system components in synovial fluid, of which at least some are distinct from any systemic changes observed. The results indicate a potential stimulatory effect of estrogen on joint tissues in vivo.
Collapse
|
35
|
Maile LA, Gill ZP, Perks CM, Holly JM. The role of cell surface attachment and proteolysis in the insulin-like growth factor (IGF)-independent effects of IGF-binding protein-3 on apoptosis in breast epithelial cells. Endocrinology 1999; 140:4040-5. [PMID: 10465274 DOI: 10.1210/endo.140.9.6984] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have recently reported that insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) can significantly increase ceramide-induced apoptosis in an Hs578T breast carcinoma cell line in an IGF-independent manner. It was observed in that study that IGFBP-3 added to the cultures was proteolytically modified, generating a specific pattern of fragmentation. We have also previously reported that almost all of the IGFBP-3 outside the circulation in extravascular fluids is in a fragmented form, apparently due to the activity of a cation-dependent serine protease. The aim of this study was to investigate the role of proteolysis in the IGFBP-3 enhancement of C2-induced apoptosis. In this study we confirmed that preincubation of Hs578T cells with IGFBP-3 enhances the apoptotic effect of the ceramide analog C2. The presence of IGF-I completely inhibited the enhancement effect, apparently by inhibiting cell surface association and proteolytic modification. The presence of a serine protease inhibitor [4-(2-aminoethyl)benesulfonyl fluoride] completely inhibited the enhancement effect of IGFBP-3, and Western immunoblotting of conditioned medium and cell surface-associated IGFBP-3 revealed that proteolytic fragmentation of the IGFBP-3 was reduced. In addition, fragments from the incubation of IGFBP-3 with plasmin were able to enhance the susceptibility of Hs578T cells to C2. The effect of these fragments could, however, also be reduced by 4-(2-aminoethyl)benesulfonyl fluoride despite the fact that IGFBP-3 was already fragmented. This suggests additional roles for serine proteases in the IGFBP-3 effect on C2-induced apoptosis in addition to the cleavage of the binding protein.
Collapse
Affiliation(s)
- L A Maile
- Department of Surgery, University of Bristol, Bristol Royal Infirmary, United Kingdom
| | | | | | | |
Collapse
|
36
|
Abstract
The GH/IGF-I axis has a clearly established role in somatic growth regulation and there is much evidence suggesting that it can play a contributing role in neoplastic tissue growth; a number of recent epidemiological reports indicate that it may also be an important determinant of cancer incidence. Whilst there have been previous reports of changes to the axis in patients with established cancers, these new studies are distinct in being prospective and the inferences that can be made from this are outlined in this review. The recent studies are considered within the context of other indirect epidemiological evidence, and together indicate that the GH/IGF-I axis may establish the level of predisposition to a number of common cancers and indeed that such risk may be programmed from early life. There is considerable evidence for a number of possible mechanisms, both direct and indirect, which could account for the associations between GH/IGF-I levels and cancer incidence; these mechanisms are briefly summarised. The implications of the new findings are then discussed in relation to the increasing clinical usage of chronic GH administration and the need for further studies to establish any consequent increase in cancer risk. Finally the opportunities for further work to optimise cancer risk assessment and risk reduction strategies are highlighted.
Collapse
Affiliation(s)
- J M Holly
- Division of Surgery, Bristol Royal Infirmary, Bristol, UK
| | | | | |
Collapse
|
37
|
Abstract
The insulin-like growth factors (IGFs) are capable of blocking apoptosis in many cell lines in vitro, potentially via activation of the IGF-I receptor (IGF-IR). We have previously shown that lower doses of the sphingolipid analogue C2-ceramide are required to induce apoptosis in IGF-IR-minus vs -positive murine fibroblasts, indicating a protective feedback loop in the latter and corroborating evidence that the IGF-IR functions as a survival receptor [1, 2]. Since, unexpectedly, C2-ceramide was capable of activating MAP kinase, phosphorylating the IGF-I receptor, and promoting entry into the G2 phase of the cell cycle, we wished to further determine the mechanisms involved. Using IGF-IR-positive fibroblasts we demonstrate here for the first time that ceramide is capable of activating a tyrosine kinase which acts at the level of the IGF-IR to increase cell death. We also demonstrate that in the presence of sodium orthovanadate, ceramide-induced death is increased, and the phosphorylation of a 75-kDa protein which associates with the IGF-I receptor is enhanced. Although the identity of this protein is not known, we speculate that it may link into the Raf kinase signaling pathway; indeed, inhibitors of MEKK reduce ceramide-induced apoptosis, thus substantiating this theory [1, 2]. Although calcium mobilization did cause apoptosis in these cells, it was not required as a mediator of ceramide-induced apoptosis. Finally, the potential hydrolysis of ceramide to sphingosine-1-phosphate was not the cause of increased MAP kinase activation, substantiating the role of an IGF-IR interacting tyrosine kinase, which may be involved in apoptosis.
Collapse
Affiliation(s)
- C E Stewart
- University Department of Surgery, Level 7, Bristol Royal Infirmary, Bristol, BS2 8 HW, England, UK.
| | | | | |
Collapse
|
38
|
Abstract
Despite the increase in laser therapy, concern remains that sublethal treatment of pre-malignant lesions may adversely affect the biological behaviour of surviving cells. Integrin receptors mediate interaction of cells with the extracellular matrix and their occupation leads to focal adhesion kinase (FAK) activation. Using our previously established model we have now investigated subcellular changes and compared integrin and FAK concentrations, the degree of FAK phosphorylation and its association with the beta1 integrin in laser vs. non-laser treated cells. We treated cells with laser generated from a frequency doubled Q-switched (Nd:YAG) laser system (532 nm) at 0.4 J/cm2 twice per week for 4 weeks. Using cell lysates we performed Western immunoblotting 24 hr later to detect integrin subunits and FAK proteins and immunoprecipitation to investigate FAK phosphorylation and its association with beta1. Cell morphology was examined using electron microscopy. SK23 and G361 cells exhibited an 3.4- and 11.2-fold increase, respectively, in FAK protein following laser treatment. FAK phosphorylation in SK23 cells was increased by 82%, whereas FAK phosphorylation in G361 cells was reduced slightly (2%). Furthermore, both alpha3 and 4 integrins were up-regulated, by approximately 4-fold and 7- to 9-fold, respectively. In addition, the beta1 integrin was proteolysed in both cell lines and the levels of FAK associated with beta1 was increased (2.1- and 2.7-fold, respectively). Finally, laser treatment of SK23 cells caused an increased number of cell processes. Sublethal 532 nm laser light thus induces changes in integrin and FAK concentrations and subsequently influences cellular attachment and morphology.
Collapse
Affiliation(s)
- N W Zhu
- University Department of Surgery, Bristol Royal Infirmary/University of Bristol, UK.
| | | | | | | |
Collapse
|
39
|
Abstract
This was a prospective observational study of maternal insulin-like growth factor binding protein-2 and -3 and fetal growth in 141 pregnant women after 24 weeks gestation who were scanned and venesected fortnightly. Cases (birthweight <5th centile) were sub-divided into those with growth restriction due to placental dysfunction (n = 25) and normal small (n = 27) and there were 89 normally grown controls. Maternal binding protein-3 was measured by radioimmunoassay and the overall pattern of the binding proteins and their proteolytic modifications were assessed by Western ligand blotting and immunoblotting followed by densitometric analysis. In controls, there was no correlation between binding protein-3 and birthweight, and binding protein-3 was elevated in the normal small but not the placental dysfunction group. Complete proteolysis of the 40 kDa doublet of binding protein-3 was observed in all pregnancies. Maternal serum binding protein-2 concentrations were unchanged in normal pregnancy compared to non-pregnant controls but elevated in the growth-restricted group and in all pregnancies binding protein-2 was predominantly present as a 14 kDa proteolysed fragment. These results suggest that compensatory changes in binding protein-2 and -3 or their proteolysis do not increase bioavailability and so do not confound the low maternal insulin-like growth factor-I in growth restricted pregnancies.
Collapse
Affiliation(s)
- R P Holmes
- Fetal Medicine Research Unit, University of Bristol, St Michael's Hospital, Southwell Street, Bristol BS2 8EG, UK
| | | | | |
Collapse
|
40
|
Helle SI, Lundgren S, Geisler S, Ekse D, Holly JM, Lønning PE. Effects of treatment with megestrol acetate on the insulin-like growth factor system: time and dose dependency. Eur J Cancer 1999; 35:1070-5. [PMID: 10533450 DOI: 10.1016/s0959-8049(99)00055-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study was designed to evaluate time and dose dependency of alterations in insulin-like growth factor (IGF)-I, free IGF-I and the functional status of IGF-binding protein (IGFBP)-3 in breast cancer patients during treatment with megestrol acetate (MA). In 16 patients receiving MA 160 mg daily, total IGF-I levels increased gradually (significant after 3 days on treatment) by a maximum of 2.66-fold after 5-6 months on treatment. However, free (readily dissociable) IGF-I levels increased to a smaller extent (1.23-2.15-fold). This discrepancy may be due to an increase in intact IGFBP-3 determined by Western ligand blotting (WLB). Similar findings were observed in 12 patients treated with MA in escalating doses from 40-800 mg daily. A dose-dependent increase in IGF-I was observed up to a dose level of 120 mg daily. We conclude that treatment with MA caused a profound increase in plasma levels of total IGF-I accompanied by a moderate increase in free IGF-I. This may explain the anabolic effects of MA in patients suffering from cachexia, but refute the hypothesis that alterations in the IGF-system may contribute to the antitumour effects of MA in breast cancer patients.
Collapse
Affiliation(s)
- S I Helle
- Department of Oncology, Haukeland University Hospital, Bergen, Norway
| | | | | | | | | | | |
Collapse
|
41
|
Holmes R, Porter H, Newcomb P, Holly JM, Soothill P. An immunohistochemical study of type I insulin-like growth factor receptors in the placentae of pregnancies with appropriately grown or growth restricted fetuses. Placenta 1999; 20:325-30. [PMID: 10329354 DOI: 10.1053/plac.1998.0387] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Insulin-like growth factors (IGFs) and their receptors in the fetus are essential for growth and postnatal survival but the role of maternal IGFs is less well understood. Animal and in vitro evidence suggests that maternal IGF-I may have important effects on placental function. Recent work in humans suggests that although there is no relationship between maternal serum IGF-I and normal fetal growth, levels are low in pregnancies complicated by fetal growth restriction due to placental dysfunction. A prospective and observational study was undertaken of the distribution and concentration of placental type I IGF receptors (IGF-IR) in women with small for gestational age (n=26) or appropriately grown (n=14) fetuses. Women were scanned biweekly from 24 weeks to delivery and cases (birthweight <5th centile) were assigned to two groups: 'fetal growth restriction' (FGR; umbilical artery pulsatility index [UAPI] > +2 s.d.; n=16) and 'normal small for gestational age' (SGA; normal UAPI, growth velocity and amniotic fluid; n=10). Immunohistochemistry of the IGF-IR was performed on formol saline-fixed placental biopsies obtained at delivery. In control pregnancies IGF-IR were present in villous endothelium and stroma, trophoblast and decidua and their distribution and density were unchanged in both SGA and FGR pregnancies. We hypothesize that a therapeutic elevation of maternal IGF-I in FGR pregnancy might lead to enhanced placental function and so fetal growth. Our findings of normal localization and density of placental IGF-IR in FGR encourage us to extend our work to look at the effects of maternal IGF-I on the transport of glucose and amino acids.
Collapse
Affiliation(s)
- R Holmes
- Fetal Medicine Research Unit, University of Bristol, St Michael's Hospital, UK
| | | | | | | | | |
Collapse
|
42
|
Perks CM, Newcomb PV, Norman MR, Holly JM. Effect of insulin-like growth factor binding protein-1 on integrin signalling and the induction of apoptosis in human breast cancer cells. J Mol Endocrinol 1999; 22:141-50. [PMID: 10194517 DOI: 10.1677/jme.0.0220141] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Interaction of epithelial cells with the extracellular matrix is mediated through integrin receptors, which transmit signals regulating cell growth, differentiation and death. Occupation of these receptors, via Arg-Gly-Asp (RGD) recognition sequences, leads to activation of focal adhesion kinase (FAK). We treated human breast cancer cell lines with RGD-containing peptides, which can disrupt integrin attachment, and investigated alterations in FAK phosphorylation, cell detachment and death. Cells grown in vitro were treated with insulin-like growth factor-binding protein-1 (IGFBP-1) and a small, synthetic RGD-containing peptide (Gly-Arg-Gly-Asp-Thr-Pro) and its negative control peptide RGE (Arg-Gly-Glu-Ser) for either 30 min followed by immunoprecipitation of cell lysates with anti-phosphotyrosine and Western immunoblotting with anti-FAK or for 24 h followed by cell counting, immunocytochemistry and flow cytometry. Both IGFBP-1 (0-800 ng/ml) and the synthetic RGD-containing peptide (1-100 microg/ml) caused significant dephosphorylation of FAK. Furthermore, after 24 h both peptides caused detachment from the matrix and the induction of apoptosis. We conclude from these data that IGFBP-1 can interact with integrin receptors to induce FAK dephosphorylation and subsequently influence attachment and cell death.
Collapse
Affiliation(s)
- C M Perks
- Division of Surgery, Department of Hospital Medicine, Level 7, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | | | | | | |
Collapse
|
43
|
Stewart CE, Newcomb PV, Savage PB, Dickens M, Tavare J, Holly JM. Increased, not decreased activation of the insulin-like growth factor (IGF) receptor signalling pathway during ceramide-induced apoptosis. Growth Horm IGF Res 1999; 9:131-142. [PMID: 10373346 DOI: 10.1054/ghir.1999.0098] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The insulin-like growth factors (IGFs) are capable of blocking apoptosis in many cell lines in vitro. The IGF-I receptor (IGF-IR) is believed to mediate protective effects of the IGFs against apoptosis. To determine whether ceramide-mediated induction of apoptosis involved a decreased survival effect of the IGF-IR, apoptosis was induced in IGF-I receptor positive (R+) and negative (R-) murine fibroblasts by incubation with increasing doses of the sphingolipid analogue, C2 ceramide. Lower ceramide doses were required to induce death in receptor negative compared with receptor positive fibroblasts (P< 0.05 at ceramide doses of 2 microM or greater), not only corroborating evidence that the IGF-I receptor functions as a survival receptor, but also suggesting that ceramide is not inducing apoptosis by suppressing a survival effect of the IGF-IR. Ceramide has been reported to induce death through suppression of MAP kinase, and activation of JUN kinase signalling; since our initial data suggested that ceramide had not affected an anti-apoptotic signalling event of the IGF-IR, we monitored the activation of these enzymes. To our surprise, in the presence of ceramide, not only was JUN kinase activity increased, but so too was MAP kinase. Inhibition of MAP kinase, using the MEKK inhibitor, PD98059, significantly reduced ceramide-induced cell death (P< 0. 001). Ceramide also enhanced IGF-induced tyrosine phosphorylation of the IGF-I receptor and activated PI-3 kinase. The cumulative effects of these events resulted in increased progression to the G2 phase of the cell cycle, arrest without subsequent mitosis, and apoptosis. These results indicate that ceramide is capable of eliciting apparently contradictory events within a single cell type, and suggest that in the presence of an IGF-IR, survival is enhanced because ceramide can activate PI-3 kinase, believed to be an anti-apoptotic enzyme.
Collapse
Affiliation(s)
- C E Stewart
- University Dept of Surgery, Bristol Royal Infirmary, Bristol, BS2 8HW, UK.
| | | | | | | | | | | |
Collapse
|
44
|
Affiliation(s)
- L A Maile
- Department of Hospital Medicine, University of Bristol Division of Surgery, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | | |
Collapse
|
45
|
Mohamed-Ali V, Pinkney JH, Panahloo A, Cwyfan-Hughes S, Holly JM, Yudkin JS. Insulin-like growth factor binding protein-1 in NIDDM: relationship with the insulin resistance syndrome. Clin Endocrinol (Oxf) 1999; 50:221-8. [PMID: 10396366 DOI: 10.1046/j.1365-2265.1999.00647.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE In order to examine the role of insulin-like growth factors in the pathogenesis of accelerated macrovascular disease in noninsulin-dependent diabetes mellitus (NIDDM), we investigated the relationship between the insulin resistance syndrome and the IGF axis. DESIGN Cross-sectional analysis of the relationship between insulin resistance syndrome variables and concentrations of IGF-1, IGF-2, IGFBP-1 and IGFBP-3 in 80 subjects with NIDDM. RESULTS After correcting for age, sex and body mass index, concentrations of IGFBP-1, correlated with those of HDL-cholesterol (r = 0.40; P < 0.001), triglycerides (r = -0.24; P = 0.04), insulin (r = -0.39; P < 0.001), intact proinsulin (r = -0.32; P = 0.006), des 31,32 proinsulin (r = -0.40; P = 0.001), and with insulin sensitivity (r = 0.38; P = 0.001) and PAI-1 activity (r = -0.24; P = 0.05); IGF-1 levels only correlated with those of HDL-cholesterol (r = -0.33; P = 0.005), and this was not explained by IGFBP-1 or insulin sensitivity. With additional correction for insulin, concentrations of IGFBP-1 still correlated with HDL-cholesterol (r = 0.40; P < 0.001), but not those of triglycerides or PAI-1 activity. There were no significant relationships between levels of IGF-2 and any of the variables investigated, and IGFBP-3 levels only correlated with those of total cholesterol (r = 0.24, P = 0.04). CONCLUSIONS In NIDDM, concentrations of IGFBP-1 are related to those of insulin, insulin sensitivity, serum lipoproteins and PAI-1 activity. The relationship between concentrations of IGFBP-1 and HDL-cholesterol is not explained by insulin. Concentrations of IGF-1 are linked to HDL-cholesterol, and this is not explained by levels of IGFBP-1. IGFBP-1 concentrations were related to PAI-1 activity, and this may be explained by insulin, which regulates the production of IGFBP-1 and PAI-1.
Collapse
Affiliation(s)
- V Mohamed-Ali
- Centre For Diabetes and Cardiovascular Risk, University College London Medical School, UK.
| | | | | | | | | | | |
Collapse
|
46
|
Perks CM, Gill ZP, Newcomb PV, Holly JM. Activation of integrin and ceramide signalling pathways can inhibit the mitogenic effect of insulin-like growth factor I (IGF-I) in human breast cancer cell lines. Br J Cancer 1999; 79:701-6. [PMID: 10070857 PMCID: PMC2362662 DOI: 10.1038/sj.bjc.6690113] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Cell counting, cell cycle analysis and Western immunoblotting were used to examine the effects of non-apoptotic doses of a ceramide analogue, C2, and a synthetic arginine-glycine-aspartic acid (RGD)-containing peptide, RGD, in MCF-7 and T47D cells to determine whether activation of these signalling pathways could alter the mitogenic potential of insulin-like growth factor I (IGF-I). IGF-I alone increased total cell number in both cell lines, associated with a rise in the percentage of cells in the S-phase of the cell cycle and a co-incident increase in cyclin A production. Treatments alone had no effects on cell number or cyclin A production relative to controls. C2 inhibited IGF-I-induced mitogenesis in both lines, whereas RGD was only effective in the T47D line. Despite inhibition of cell proliferation, IGF-I stimulation of cells in S-phase and of cyclin A levels were unaffected; however, an IGF-I-induced increase in cyclin B1 levels was inhibited by 30%. Low-dose induction of integrin and ceramide signalling pathways causes cells to be blocked in S-phase, thereby inhibiting the normal cycle of events associated with the IGF-I-induced mitotic signal. Activating these pathways may not only restrict tumour growth by induction of apoptosis but they may also directly inhibit IGF-I-induced cell proliferation.
Collapse
Affiliation(s)
- C M Perks
- Division of Surgery, Department of Hospital Medicine, Bristol Royal Infirmary, UK
| | | | | | | |
Collapse
|
47
|
Walter HJ, Berry M, Hill DJ, Cwyfan-Hughes S, Holly JM, Logan A. Distinct sites of insulin-like growth factor (IGF)-II expression and localization in lesioned rat brain: possible roles of IGF binding proteins (IGFBPs) in the mediation of IGF-II activity. Endocrinology 1999; 140:520-32. [PMID: 9886865 DOI: 10.1210/endo.140.1.6463] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although expression of the IGF-II has been demonstrated within the central nervous system (CNS), past studies have failed to reveal its precise roles or responses subsequent to a traumatic injury. To demonstrate that IGF-II, IGFBP, and IGF receptor (-R) expression alters in response to a penetrating CNS injury, we used the techniques of ribonuclease protection assay, in situ hybridization, immunohistochemistry, Western blotting, and RIA. Under normal physiology, IGF-II expression is restricted to the mesenchymal support structures of the brain, including the choroid plexus, where its expression is coincident with that of IGFBP-2. Between 1-7 days post lesion (dpl), in the acute phase following a penetrant wound to the CNS, IGF-II and IGF-IIR protein, but not messenger RNA, were colocalized, with IGF-I, IGF-IR, and IGFBP-1, -2, -3, and -6, to neurons, macrophages, astrocytes, and microglia within the damaged tissue. Within the cerebrospinal fluid (CSF), levels of IGF-II peptide increased to peak at 7 dpl. IGFBP-2, -3, and -6 were also observed within the CSF, with IGFBP-2 predominating and exhibiting an increase in binding efficiency from 7-10 dpl. In the chronic phase of injury (7-14 dpl), an increase in both IGF-II, IGF-IIR and IGFBP-5 messenger RNA and protein was observed specifically and focally in the marginal astrocytes forming the limiting glial membrane of the wound. Thus, our evidence suggests that there are two mechanisms of action for IGF-II within the injured rat brain. During the acute phase, the secretion of IGF-II from the choroid plexus into the CSF is up-regulated, resulting in increased transport of the peptide to the wound. In the CSF, transported IGF-II is complexed to IGFBP-2 and essentially demonstrates an endocrine mode of action with a balance of locally produced IGFBPs modulating its bioactivity in the wound. Later in the wounding response, levels of IGF-II decline in the CSF and the wound neuropil, possibly with the aid of increased IGFBP-5 levels that may help to locally sequester and down-regulate IGF-II activity. Hence, in the chronic phase of the injury response, IGF-II reasserts itself to a predominantly autocrine/paracrine role restricted to the mesenchymal support structures, including the glia limitans, which may help reestablish and maintain tissue homeostasis.
Collapse
Affiliation(s)
- H J Walter
- Department of Medicine, University of Birmingham, United Kingdom
| | | | | | | | | | | |
Collapse
|
48
|
Holmes RP, Holly JM, Soothill PW. A prospective study of maternal serum insulin-like growth factor-I in pregnancies with appropriately grown or growth restricted fetuses. Br J Obstet Gynaecol 1998; 105:1273-8. [PMID: 9883918 DOI: 10.1111/j.1471-0528.1998.tb10005.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To determine whether there is a relationship between maternal serum insulin-like growth factor-I and fetal growth, consistent with the hypothesis that insulin-like growth factor-I influences maternal constraint upon fetal growth by controlling placental transfer. DESIGN A prospective, observational study. SETTING Fetal medicine unit and antenatal clinic of a large teaching hospital. POPULATION One hundred and forty-one pregnant women identified as having small or normally grown fetuses. METHODS Fetuses were scanned every two weeks with maternal venesection at each visit. Cases (birthweight < 5th centile) were assigned to two groups: fetal growth restriction due to placental dysfunction (umbilical artery Doppler, growth velocity pulsatility index > +2 SD; n = 25) and normal small-for-gestational-age (normal Doppler, growth velocity and amniotic fluid; n = 27). Eighty-nine controls had birthweights between the 5th and the 95th centiles, normal Doppler, growth velocity and amniotic fluid. Insulin-like growth factor-I was measured by radioimmunoassay, and its relationship to gestational age and birthweight was assessed by regression analysis. Comparisons between case groups were made by Student's t test or analysis of covariance to allow for the effect of birthweight. OUTCOME MEASURE The last insulin-like growth factor-I level before delivery within the different subgroups. RESULTS In controls, maternal insulin-like growth factor-I increased with gestational age (r = 0.40; P = 0.0001) but did not correlate with birthweight. Insulin-like growth factor-I was low in the mothers of growth restricted fetuses (-1.56 SD; P = 0.0001), but not in those with small-for-gestational age fetuses. CONCLUSIONS The control and small-for-gestational-age data suggest that maternal insulin-like growth factor-I is not associated with endocrine control of normal placental function. Low insulin-like growth factor-I relates to poor placental transfer, as indicated by Doppler, rather than to low birthweight. Whether this is a regulatory mechanism, a cause or a consequence of placental dysfunction needs further study.
Collapse
Affiliation(s)
- R P Holmes
- Fetal Medicine Research Unit, University of Bristol, St Michael's Hospital, UK
| | | | | |
Collapse
|
49
|
Maile LA, Xu S, Cwyfan-Hughes SC, Fernihough JK, Pell JM, Holly JM. Active and inhibitory components of the insulin-like growth factor binding protein-3 protease system in adult serum, interstitial, and synovial fluid. Endocrinology 1998; 139:4772-81. [PMID: 9832413 DOI: 10.1210/endo.139.12.6359] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Circulating insulin-like growth factor binding protein-3 (IGFBP-3) proteolytic activity is normally low but increases in serum from pregnant women and from patients with various pathologies. In contrast, we have recently reported that outside the circulation, such activity is normally high but decreases in various pathologies. We have now compared components of the IGFBP-3 proteolytic system revealed after size fractionation of serum and extravascular fluids with different intrinsic levels of such activity. Normal serum, serum from pregnant women, and synovial fluid from patients with rheumatoid arthritis revealed high and low molecular weight (MW) areas of activity. However, only the low MW activity was apparent in interstitial fluid from normal skin (N Inst F) or psoriatic lesions (P Inst F) and in synovial fluid from normal volunteers (N Syn F) or patients with osteoarthritis (OA Syn F). Addition of inhibitors revealed both areas to comprise more than one enzyme, including serine proteases and metalloproteinases; both could also be inhibited by P Inst F, NS, RA Syn F, and inhibitory fractions from the separation of the latter two. These findings demonstrate low and high MW regions of proteolytic activity, which may contribute to the IGFBP-3 protease system, the former always present, whereas the latter seems to be retained within the circulation apart from inflammatory conditions. The variations apparent in IGFBP-3 protease activity in the intact samples related to the presence of an inhibitor, which may protect IGFBP-3 from proteolysis, rather than to changes in the component proteases.
Collapse
Affiliation(s)
- L A Maile
- University of Bristol, Department of Hospital Medicine, Bristol Royal Infirmary, United Kingdom
| | | | | | | | | | | |
Collapse
|
50
|
Affiliation(s)
- D J Gunnell
- Department of Social Medicine, Canynge Hall, Bristol BS8 2PR, UK.
| | | | | | | |
Collapse
|