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Failure to up-regulate VEGF165b in maternal plasma is a first trimester predictive marker for pre-eclampsia. Clin Sci (Lond) 2009; 116:265-72. [PMID: 18826376 PMCID: PMC2635543 DOI: 10.1042/cs20080270] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Pre-eclampsia is a pregnancy-related condition characterized by hypertension,
proteinuria and endothelial dysfunction. VEGF165b, formed by
alternative splicing of VEGF (vascular endothelial growth factor) pre-mRNA,
inhibits VEGF165-mediated vasodilation and angiogenesis, but has not
been quantified in pregnancy. ELISAs were used to measure
means±S.E.M. plasma VEGF165b, sEng (soluble endoglin) and
sFlt-1 (soluble fms-like tyrosine kinase-1). At 12 weeks of
gestation, the plasma VEGF165b concentration was significantly
up-regulated in plasma from women who maintained normal blood pressure
throughout their pregnancy (normotensive group,
4.90±1.6 ng/ml; P<0.01, as
determined using a Mann-Whitney U test) compared with
non-pregnant women (0.40±0.22 ng/ml). In contrast, in
patients who later developed pre-eclampsia, VEGF165b levels were
lower than in the normotensive group (0.467±0.209 ng/ml),
but were no greater than non-pregnant women. At term, plasma VEGF165b
concentrations were greater than normal in both pre-eclamptic
(3.75±2.24 ng/ml) and normotensive
(10.58 ng/ml±3.74 ng/ml;
P>0.1 compared with pre-eclampsia) pregnancies.
Patients with a lower than median plasma VEGF165b at
12 weeks had elevated sFlt-1 and sEng pre-delivery. Concentrations of
sFlt-1 (1.20±0.07 and 1.27±0.18 ng/ml) and sEng
(4.4±0.18 and 4.1±0.5 ng/ml) were similar at
12 weeks of gestation in the normotensive and pre-eclamptic groups
respectively. Plasma VEGF165b levels were elevated in pregnancy, but
this increase is delayed in women that subsequently develop pre-eclampsia. In
conclusion, low VEGF165b may therefore be a clinically useful first
trimester plasma marker for increased risk of pre-eclampsia.
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102
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Nowak DG, Woolard J, Amin EM, Konopatskaya O, Saleem MA, Churchill AJ, Ladomery MR, Harper SJ, Bates DO. Expression of pro- and anti-angiogenic isoforms of VEGF is differentially regulated by splicing and growth factors. J Cell Sci 2009; 121:3487-95. [PMID: 18843117 DOI: 10.1242/jcs.016410] [Citation(s) in RCA: 253] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Vascular endothelial growth factor A (VEGFA; hereafter referred to as VEGF) is a key regulator of physiological and pathological angiogenesis. Two families of VEGF isoforms are generated by alternate splice-site selection in the terminal exon. Proximal splice-site selection (PSS) in exon 8 results in pro-angiogenic VEGFxxx isoforms (xxx is the number of amino acids), whereas distal splice-site selection (DSS) results in anti-angiogenic VEGFxxxb isoforms. To investigate control of PSS and DSS, we investigated the regulation of isoform expression by extracellular growth factor administration and intracellular splicing factors. In primary epithelial cells VEGFxxxb formed the majority of VEGF isoforms (74%). IGF1, and TNFalpha treatment favoured PSS (increasing VEGFxxx) whereas TGFbeta1 favoured DSS, increasing VEGFxxxb levels. TGFbeta1 induced DSS selection was prevented by inhibition of p38 MAPK and the Clk/sty (CDC-like kinase, CLK1) splicing factor kinase family, but not ERK1/2. Clk phosphorylates SR protein splicing factors ASF/SF2, SRp40 and SRp55. To determine whether SR splicing factors alter VEGF splicing, they were overexpressed in epithelial cells, and VEGF isoform production assessed. ASF/SF2, and SRp40 both favoured PSS, whereas SRp55 upregulated VEGFxxxb (DSS) isoforms relative to VEGFxxx. SRp55 knockdown reduced expression of VEGF165b. Moreover, SRp55 bound to a 35 nucleotide region of the 3'UTR immediately downstream of the stop codon in exon 8b. These results identify regulation of splicing by growth and splice factors as a key event in determining the relative pro-versus anti-angiogenic expression of VEGF isoforms, and suggest that p38 MAPK-Clk/sty kinases are responsible for the TGFbeta1-induced DSS selection, and identify SRp55 as a key regulatory splice factor.
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Affiliation(s)
- Dawid G Nowak
- Microvascular Research Laboratories, Bristol Heart Institute, Department of Physiology and Pharmacology, School of Veterinary Sciences, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
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103
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Abstract
The physiology of microvessels limits the growth and development of tumours. Tumours gain nutrients and excrete waste through growth-associated microvessels. New anticancer therapies target this microvasculature by inhibiting vascular endothelial growth factor A (VEGF-A) splice isoforms that promote microvessel growth. However, certain VEGF-A splice isoforms in normal tissues inhibit growth of microvessels. Thus, it is the VEGF-A isoform balance, which is controlled by mRNA splicing, that orchestrates angiogenesis. Here, we highlight the functional differences between the pro-angiogenic and the anti-angiogenic VEGF-A isoform families and the potential to harness the synthetic capacity of cancer cells to produce factors that inhibit, rather than aid, cancer growth.
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Affiliation(s)
- Steven J Harper
- Microvascular Research Laboratories, Department of Physiology & Pharmacology, Bristol Heart Institute, School of Veterinary Science, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK.
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104
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Rich RL, Myszka DG. Survey of the year 2007 commercial optical biosensor literature. J Mol Recognit 2008; 21:355-400. [DOI: 10.1002/jmr.928] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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105
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106
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Akhavani MA, Sivakumar B, Paleolog EM, Kang N. Angiogenesis and plastic surgery. J Plast Reconstr Aesthet Surg 2008; 61:1425-37. [PMID: 18835232 DOI: 10.1016/j.bjps.2008.05.041] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 03/27/2008] [Accepted: 05/29/2008] [Indexed: 01/23/2023]
Abstract
SUMMARY Angiogenesis, the formation of new blood vessels from an existing vascular bed, is a normal physiological process which also underpins many--apparently unrelated--pathological states. It is an integral factor in determining the success or failure of many procedures in plastic and reconstructive surgery. As a result, the ability to control the process would be of great therapeutic benefit. To appreciate the potential benefits and limitations of recent advances in our understanding of angiogenesis, it is important to comprehend the basic physiology of blood vessel formation. This review aims to summarise current knowledge of the way in which angiogenesis is controlled and to look at how disordered vessel development results in pathology relevant to plastic surgery. Through this we hope to provide a comprehensive overview of the recent advances in angiogenesis as they relate to plastic surgery, particularly the promotion of flap survival, tendon healing, nerve regeneration, fracture healing and ulcer treatments.
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107
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Díaz R, Peña C, Silva J, Lorenzo Y, García V, García JM, Sánchez A, Espinosa P, Yuste R, Bonilla F, Domínguez G. p73 isoforms affect VEGF, VEGF165b and PEDF expression in human colorectal tumors: VEGF165b downregulation as a marker of poor prognosis. Int J Cancer 2008; 123:1060-7. [DOI: 10.1002/ijc.23619] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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108
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Nyagol J, De Falco G, Lazzi S, Luzzi A, Cerino G, Shaheen S, Palummo N, Bellan C, Spina D, Leoncini L. HIV-1 Tat mimetic of VEGF correlates with increased microvessels density in AIDS-related diffuse large B-cell and Burkitt lymphomas. J Hematop 2008; 1:3-10. [PMID: 19669199 PMCID: PMC2712328 DOI: 10.1007/s12308-008-0002-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Accepted: 02/19/2008] [Indexed: 01/16/2023] Open
Abstract
Angiogenic switch marks the beginning of tumor’s strategy to acquire independent blood supply. In some subtypes of non-Hodgkin’s lymphomas, higher local vascular endothelial growth factor (VEGF) expression correlates with increased microvessel density. However, this local VEGF expression is higher only in tumors with elevated expression of the receptors of the growth factor, suggesting an autocrine growth-promoting feedback loop. Several studies have indicated that VEGF receptors are also targeted by Tat protein from the HIV-1-infected cells. Given the similarity of the basic region of Tat to the angiogenic factors (basic fibroblast growth factor, VEGF), Tat mimics these proteins and binds to their receptors. We evaluated the role of HIV-1 Tat in regulating the level of VEGF expression and microvessel density in the AIDS-related diffuse large B-cell (DLBCL) and Burkitt lymphomas (BL). By luciferase assay, we showed that VEGF promoter activity was downregulated in vitro in cells transfected with Tat. Reduced VEGF protein expression in primary HIV-1 positive BL and DLBCL, compared to the negative cases, supported the findings of promoter downregulation from the cell lines. Microvascular density assessed by CD34 expression was, however, higher in HIV-1 positive than in HIV-1 negative tumors. These results suggest that Tat has a wider angiogenic role, besides the regulation of VEGF expression. Thus, targeting Tat protein itself and stabilizing transient silencing of VEGF expression or use of monoclonal antibodies against their receptors in the AIDS-associated tumors will open a window for future explorable pathways in the management of angiogenic phenotypes in the AIDS-associated non-Hodgkin’s lymphomas.
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Affiliation(s)
- J. Nyagol
- Department of Human Pathology and Oncology, University of Siena, Via Delle Scotte 6, 53100 Siena, Italy
| | - G. De Falco
- Department of Human Pathology and Oncology, University of Siena, Via Delle Scotte 6, 53100 Siena, Italy
| | - S. Lazzi
- Department of Human Pathology and Oncology, University of Siena, Via Delle Scotte 6, 53100 Siena, Italy
| | - A. Luzzi
- Department of Human Pathology and Oncology, University of Siena, Via Delle Scotte 6, 53100 Siena, Italy
| | - G. Cerino
- Department of Human Pathology and Oncology, University of Siena, Via Delle Scotte 6, 53100 Siena, Italy
| | - S. Shaheen
- Department of Pathology, Aga Khan University Hospital, Nairobi, Kenya
| | - N. Palummo
- Department of Human Pathology and Oncology, University of Siena, Via Delle Scotte 6, 53100 Siena, Italy
| | - C. Bellan
- Department of Human Pathology and Oncology, University of Siena, Via Delle Scotte 6, 53100 Siena, Italy
| | - D. Spina
- Department of Human Pathology and Oncology, University of Siena, Via Delle Scotte 6, 53100 Siena, Italy
| | - L. Leoncini
- Department of Human Pathology and Oncology, University of Siena, Via Delle Scotte 6, 53100 Siena, Italy
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109
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Abstract
Vascular endothelial growth factor-A is widely regarded as the principal stimulator of angiogenesis required for tumour growth. VEGF is generated as multiple isoforms of two families, the pro-angiogenic family generated by proximal splice site selection in the terminal exon, termed VEGFxxx, and the anti-angiogenic family formed by distal splice site selection in the terminal exon, termed VEGFxxxb, where xxx is the amino acid number. The most studied isoforms, VEGF165 and VEGF165b have been shown to be present in tumour and normal tissues respectively. VEGF165b has been shown to inhibit VEGF- and hypoxia-induced angiogenesis, and VEGF-induced cell migration and proliferation in vitro. Here we show that overexpression of VEGF165b by tumour cells inhibits the growth of prostate carcinoma, Ewing's sarcoma and renal cell carcinoma in xenografted mouse tumour models. Moreover, VEGF165b overexpression inhibited tumour cell-mediated migration and proliferation of endothelial cells. These data show that overexpression of VEGF165b can inhibit growth of multiple tumour types in vivo indicating that VEGF165b has potential as an anti-angiogenic, anti-tumour strategy in a number of different tumour types, either by control of VEGF165b expression by regulation of splicing, overexpression of VEGF165b, or therapeutic delivery of VEGF165b to tumours.
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110
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VEGF 165 b, an antiangiogenic VEGF-A isoform, binds and inhibits bevacizumab treatment in experimental colorectal carcinoma: balance of pro- and antiangiogenic VEGF-A isoforms has implications for therapy. Br J Cancer 2008; 98:1366-79. [PMID: 18349829 PMCID: PMC2361696 DOI: 10.1038/sj.bjc.6604308] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Bevacizumab, an anti-vascular endothelial growth factor (VEGF-A) antibody, is used in metastatic colorectal carcinoma (CRC) treatment, but responses are unpredictable. Vascular endothelial growth factor is alternatively spliced to form proangiogenic VEGF165 and antiangiogenic VEGF165b. Using isoform-specific enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, we found that over 90% of the VEGF in normal colonic tissue was VEGFxxxb, but there was a variable upregulation of VEGFxxx and downregulation of VEGFxxxb in paired human CRC samples. Furthermore, cultured colonic adenoma cells expressed predominantly VEGFxxxb, whereas colonic carcinoma cells expressed predominantly VEGFxxx. However, adenoma cells exposed to hypoxia switched their expression from predominantly VEGFxxxb to predominantly VEGFxxx. VEGF165b overexpression in LS174t colon cancer cells inhibited colon carcinoma growth in mouse xenograft models. Western blotting and surface plasmon resonance showed that VEGF165b bound to bevacizumab with similar affinity as VEGF165. However, although bevacizumab effectively inhibited the rapid growth of colon carcinomas expressing VEGF165, it did not affect the slower growth of tumours from colonic carcinoma cells expressing VEGF165b. Both bevacizumab and anti-VEGF165b-specific antibodies were cytotoxic to colonic epithelial cells, but less so to colonic carcinoma cells. These results show that the balance of antiangiogenic to proangiogenic isoforms switches to a variable extent in CRC, regulates tumour growth rates and affects the sensitivity of tumours to bevacizumab by competitive binding. Together with the identification of an autocrine cytoprotective role for VEGF165b in colonic epithelial cells, these results indicate that bevacizumab treatment of human CRC may depend upon this balance of VEGF isoforms.
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111
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Qiu Y, Bevan H, Weeraperuma S, Wratting D, Murphy D, Neal CR, Bates DO, Harper SJ. Mammary alveolar development during lactation is inhibited by the endogenous antiangiogenic growth factor isoform, VEGF165b. FASEB J 2007; 22:1104-12. [PMID: 18032632 DOI: 10.1096/fj.07-9718com] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Extensive tissue remodeling occurs in breast tissue during pregnancy, resulting in growth and development of the mammary gland associated with extensive vascular remodeling, which is thought to be dependent on vascular endothelial growth factor (VEGF). We show here that the endogenous antiangiogenic splice isoform of VEGF, VEGF(165)b, is normally expressed in nonlactating human and mouse breast, and is down-regulated in WT mice during lactation. To demonstrate the physiological role of VEGF(165)b in mammary tissue, we generated transgenic (TG) mice expressing VEGF(165)b, under the control of the mouse mammary tumor virus (MMTV) enhancer/promoter. These mice increase expression of VEGF(165)b in mammary tissue during mammary development. The offspring of TG mothers, but not TG fathers, die shortly after birth. The female TG mice have fewer blood vessels, less blood in the mammary tissue, and impaired alveolar coverage of the fat pad, and do not produce sufficient milk for nourishment of their pups. These findings demonstrate that endogenous overexpression of VEGF(165)b in the mammary gland inhibits physiological angiogenesis and that the regulation of the balance of VEGF isoforms is a requirement for mammary alveolar development and milk production. This study provides the first evidence for the role of endogenous antiangiogenic VEGF isoforms in normal physiology--their down-regulation is required for effective milk production.
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Affiliation(s)
- Yan Qiu
- Microvascular Research Laboratories, School of Veterinary Sciences, University of Bristol, Bristol, UK
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