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Koc-Gunel S, Gautam LK, Calvert BA, Murthy S, Harriott NC, Nawroth JC, Zhou B, Krymskaya VP, Ryan AL. Sorafenib inhibits invasion of multicellular organoids that mimic Lymphangioleiomyomatosis nodules. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.12.544372. [PMID: 37398026 PMCID: PMC10312665 DOI: 10.1101/2023.06.12.544372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Lymphangioleiomyomatosis (LAM) is a debilitating, progressive lung disease with few therapeutic options, largely due to a paucity of mechanistic knowledge of disease pathogenesis. Lymphatic endothelial cells (LECs) are known to envelope and invade clusters of LAM-cells, comprising of smooth muscle α-actin and/or HMB-45 positive "smooth muscle-like cells" however the role of LECs in LAM pathogenesis is still unknown. To address this critical knowledge gap, we investigated wether LECs interact with LAM-cells to augment their metastatic behaviour of LAM-cells. We performed in situ spatialomics and identified a core of transcriptomically related cells within the LAM nodules. Pathway analysis highlights wound and pulmonary healing, VEGF signaling, extracellular matrix/actin cytoskeletal regulating and the HOTAIR regulatory pathway enriched in the LAM Core cells. We developed an organoid co-culture model combining primary LAM-cells with LECs and applied this to evaluate invasion, migration, and the impact of Sorafenib, a multi-kinase inhibitor. LAM-LEC organoids had significantly higher extracellular matrix invasion, decreased solidity and a greater perimeter, reflecting increased invasion compared to non-LAM control smooth muscle cells. Sorafenib significantly inhibited this invasion in both LAM spheroids and LAM-LEC organoids compared to their respective controls. We identified TGFβ1ι1, a molecular adapter coordinating protein-protein interactions at the focal adhesion complex and known to regulate VEGF, TGFβ and Wnt signalling, as a Sorafenib-regulated kinase in LAM-cells. In conclusion we have developed a novel 3D co-culture LAM model and have demonstrated the effectiveness of Sorafenib to inhibit LAM-cell invasion, identifying new avenues for therapeutic intervention.
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Affiliation(s)
- Sinem Koc-Gunel
- Hastings Center for Pulmonary Research, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA, USA
- Institute of Medical Virology, University Hospital Frankfurt, Goethe University, Frankfurt, D-60596, Germany
| | - Lalit K. Gautam
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Ben A. Calvert
- Hastings Center for Pulmonary Research, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Shubha Murthy
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Noa C. Harriott
- Hastings Center for Pulmonary Research, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Janna C. Nawroth
- Hastings Center for Pulmonary Research, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA, USA
- Helmholtz Pioneer Campus and Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
- Biological Imaging, Central Institute for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, D-81675, Germany
| | - Beiyun Zhou
- Hastings Center for Pulmonary Research, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Vera P. Krymskaya
- Division of Pulmonary and Critical Care Medicine, Lung Biology Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Amy L. Ryan
- Hastings Center for Pulmonary Research, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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de Paula A, Abdolrahimzadeh S, Fragiotta S, Di Pippo M, Scuderi G. Current concepts on ocular vascular abnormalities in the phakomatoses. Semin Ophthalmol 2021; 36:549-560. [PMID: 33755531 DOI: 10.1080/08820538.2021.1900284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Neurofibromatosis, Von Hippel Lindau disease, and tuberous sclerosis complex are classified under the term phakomatoses. They are characterized by ocular vascular abnormalities such as vascular tortuosity, corkscrew retinal vessel configuration, moyamoya-like aspect, microaneurysms, hemangioblastomas, and focal sheathing of retinal arteries, possibly due to abnormal formation, migration, and differentiation of neural crest cells. These alterations can be the first sign or the hallmark of disease and can be related to vasoproliferative tumors. PURPOSE Novel imaging technologies in ophthalmology, such as near-infrared reflectances and spectral domain optical coherence tomography, have improved our knowledge in the diagnosis of these pathologies. Previously undetected macular vascular alterations have been reported in phakomatoses using optical coherence tomography angiography. This review will summarize the ophthalmic vascular abnormalities and novel imaging methods in the phakomatoses. CONCLUSION Active research is being led into the ophthalmic management of these conditions and their complications, and owing to elevated vascular endothelial growth factor production from hemangioblastoma, hamartoma, and retinal vascular proliferative tumors, increasing interest in this line of therapy has been conducted although research is still ongoing in this area.
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Affiliation(s)
- Alessandro de Paula
- NESMOS Department, Ophthalmology Unit, St. Andrea Hospital, University of Rome La Sapienza, Rome, Italy
| | - Solmaz Abdolrahimzadeh
- NESMOS Department, Ophthalmology Unit, St. Andrea Hospital, University of Rome La Sapienza, Rome, Italy
| | - Serena Fragiotta
- NESMOS Department, Ophthalmology Unit, St. Andrea Hospital, University of Rome La Sapienza, Rome, Italy
| | - Mariachiara Di Pippo
- NESMOS Department, Ophthalmology Unit, St. Andrea Hospital, University of Rome La Sapienza, Rome, Italy
| | - Gianluca Scuderi
- NESMOS Department, Ophthalmology Unit, St. Andrea Hospital, University of Rome La Sapienza, Rome, Italy
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Rajasekaran NM, Horo S, Kuriakose T. Primary ocular presentation of tuberous sclerosis - A case report. Indian J Ophthalmol 2019; 67:433-435. [PMID: 30777981 PMCID: PMC6407376 DOI: 10.4103/ijo.ijo_925_18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A 25-year-old man presented with decreased vision in the left eye with hypopigmented elevated subretinal lesion over the optic disk with abnormal vasculature, subretinal and retinal hemorrhages, and fluid in the macula. An area of high spike over the disk with corresponding orbital shadowing was seen on B scan ultrasonography. Fundus fluorescein angiography revealed abnormal vasculature. Systemic examination revealed facial angiofibroma, ashleaf spot, and dental pits with multiple cortical tubers on CT brain. Intravitreal injection of bevacizumab led to visual and tomographic improvement. Abnormal retinal vascularization and exudation in young individuals may be a presenting feature in tuberous sclerosis.
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Affiliation(s)
- Nancy M Rajasekaran
- Department of Ophthalmology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Saban Horo
- Department of Ophthalmology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Thomas Kuriakose
- Department of Ophthalmology, Christian Medical College, Vellore, Tamil Nadu, India
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Leech JD, Lammers SHT, Goldman S, Auricchio N, Bronson RT, Kwiatkowski DJ, Sahin M. A vascular model of Tsc1 deficiency accelerates renal tumor formation with accompanying hemangiosarcomas. Mol Cancer Res 2014; 13:548-55. [PMID: 25548102 DOI: 10.1158/1541-7786.mcr-14-0178] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
UNLABELLED Tuberous sclerosis complex (TSC) is an autosomal disease caused by inactivating mutations in either of the tumor suppressor genes TSC1 or TSC2. TSC-associated tumor growth is present in multiple tissues and organs including brain, kidney, liver, heart, lungs, and skin. In the kidney, TSC angiomyolipomas have aberrant vascular structures with abnormal endothelial cells, suggesting a role for endothelial mTORC1 function. In the current report, a genetically engineered mouse model (GEMM) with a conditional knockout allele of Tsc1 with a Darpp32-Cre allele displayed accelerated formation of both kidney cystadenomas and paw hemangiosarcomas. All mutant mice developed hemangiosarcomas on multiple paws by 6 weeks of age. By 16 weeks of age, the average mutant hind paw was 4.0 mm in diameter, nearly double the size of control mice. Furthermore, the hemangiosarcomas and kidney cystadenomas were responsive to intraperitoneal rapamycin treatment. Immunoblotting and immunostaining for phospho-S6 (pS6) and phospho-CAD showed that the effect of rapamycin on tumor size was through inhibition of the mTOR signaling pathway. Finally, elevated VEGF mRNA levels were also observed in hemangiosarcoma specimens. Because paw hemangiosarcomas are easily detectable and scorable for size and growth, this novel mouse model enables accelerated in vivo drug testing for therapies of TSC-related tumors. IMPLICATIONS These findings provide a strong rationale for simultaneous use of this conditional knockout mouse as an in vivo genetic model while seeking new cancer therapies for TSC-related tumors.
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Affiliation(s)
- Jarrett D Leech
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts
| | - Stephen H T Lammers
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts
| | - Sam Goldman
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts
| | - Neil Auricchio
- Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Roderick T Bronson
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts
| | | | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts.
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Delaney SP, Julian LM, Stanford WL. The neural crest lineage as a driver of disease heterogeneity in Tuberous Sclerosis Complex and Lymphangioleiomyomatosis. Front Cell Dev Biol 2014; 2:69. [PMID: 25505789 PMCID: PMC4243694 DOI: 10.3389/fcell.2014.00069] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/02/2014] [Indexed: 12/20/2022] Open
Abstract
Lymphangioleiomyomatosis (LAM) is a rare neoplastic disease, best characterized by the formation of proliferative nodules that express smooth muscle and melanocytic antigens within the lung parenchyma, leading to progressive destruction of lung tissue and function. The pathological basis of LAM is associated with Tuberous Sclerosis Complex (TSC), a multi-system disorder marked by low-grade tumors in the brain, kidneys, heart, eyes, lung and skin, arising from inherited or spontaneous germ-line mutations in either of the TSC1 or TSC2 genes. LAM can develop either in a patient with TSC (TSC-LAM) or spontaneously (S-LAM), and it is clear that the majority of LAM lesions of both forms are characterized by an inactivating mutation in either TSC1 or TSC2, as in TSC. Despite this genetic commonality, there is considerable heterogeneity in the tumor spectrum of TSC and LAM patients, the basis for which is currently unknown. There is extensive clinical evidence to suggest that the cell of origin for LAM, as well as many of the TSC-associated tumors, is a neural crest cell, a highly migratory cell type with extensive multi-lineage potential. Here we explore the hypothesis that the types of tumors that develop and the tissues that are affected in TSC and LAM are dictated by the developmental timing of TSC gene mutations, which determines the identities of the affected cell types and the size of downstream populations that acquire a mutation. We further discuss the evidence to support a neural crest origin for LAM and TSC tumors, and propose approaches for generating humanized models of TSC and LAM that will allow cell of origin theories to be experimentally tested. Identifying the cell of origin and developing appropriate humanized models is necessary to truly understand LAM and TSC pathology and to establish effective and long-lasting therapeutic approaches for these patients.
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Affiliation(s)
- Sean P Delaney
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa, ON, Canada ; Faculty of Graduate and Postdoctoral Studies, University of Ottawa Ottawa, ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada
| | - Lisa M Julian
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa, ON, Canada ; Faculty of Graduate and Postdoctoral Studies, University of Ottawa Ottawa, ON, Canada
| | - William L Stanford
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa, ON, Canada ; Faculty of Graduate and Postdoctoral Studies, University of Ottawa Ottawa, ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada ; Department of Biochemistry, Microbiology, and Immunology, University of Ottawa Ottawa, ON, Canada
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Glasgow CG, El-Chemaly S, Moss J. Lymphatics in lymphangioleiomyomatosis and idiopathic pulmonary fibrosis. Eur Respir Rev 2013; 21:196-206. [PMID: 22941884 DOI: 10.1183/09059180.00009311] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The primary function of the lymphatic system is absorbing and transporting macromolecules and immune cells to the general circulation, thereby regulating fluid, nutrient absorption and immune cell trafficking. Lymphangiogenesis plays an important role in tissue inflammation and tumour cell dissemination. Lymphatic involvement is seen in lymphangioleiomyomatosis (LAM) and idiopathic pulmonary fibrosis (IPF). LAM, a disease primarily affecting females, involves the lung (cystic destruction), kidney (angiomyolipoma) and axial lymphatics (adenopathy and lymphangioleiomyoma). LAM occurs sporadically or in association with tuberous sclerosis complex (TSC). Cystic lung destruction results from proliferation of LAM cells, which are abnormal smooth muscle-like cells with mutations in the TSC1 or TSC2 gene. Lymphatic abnormalities arise from infiltration of LAM cells into the lymphatic wall, leading to damage or obstruction of lymphatic vessels. Benign appearing LAM cells possess metastatic properties and are found in the blood and other body fluids. IPF is a progressive lung disease resulting from fibroblast proliferation and collagen deposition. Lymphangiogenesis is associated with pulmonary destruction and disease severity. A macrophage subset isolated from IPF bronchoalveolar lavage fluid (BALF) express lymphatic endothelial cell markers in vitro, in contrast to the same macrophage subset from normal BALF. Herein, we review lymphatic involvement in LAM and IPF.
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Affiliation(s)
- Connie G Glasgow
- Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1590, USA
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Tomida M, Mitamura Y, Katome T, Eguchi H, Naito T, Harada T. Aggressive retinal astrocytoma associated with tuberous sclerosis. Clin Ophthalmol 2012; 6:715-20. [PMID: 22654497 PMCID: PMC3363316 DOI: 10.2147/opth.s31759] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We report the case of a patient with an aggressive retinal astrocytoma accompanied with macular edema and neovascular vessels, who was initially treated with intravitreal bevacizumab injections. A 24-year-old male presented to our clinic complaining of visual disturbance in his right eye. At 8 years of age, he had been diagnosed as having tuberous sclerosis complex. Fundus examination demonstrated a retinal tumor accompanied with marked neovascular vessels on the surface, retinal hemorrhage, and macular edema. After six monthly intravitreal bevacizumab injections, fundus examination demonstrated marked regression of the macular edema and neovascular vessels. Two months later, a vitreous hemorrhage developed which necessitated pars plana vitrectomy. After additional intravitreal bevacizumab injection for preventing intraoperative bleeding, vitrectomy with endophotocoagulation for the tumor was performed. The vitreous sample was obtained during vitrectomy, and we measured the vascular endothelial growth factor concentration by enzyme-linked immunosorbent assay. The surgically removed epiretinal neovascular membrane and biopsied retinal tumor expressed vascular endothelial growth factor, although several intravitreal bevacizumab injections led to a vitreous vascular endothelial growth factor concentration of undetectable levels. The clinical course and immunohistochemical analyses indicate that intravitreal bevacizumab monotherapy may have been insufficient to treat the aggressive retinal astrocytoma with macular edema and that laser photocoagulation or photodynamic therapy for the tumor should be considered following intravitreal bevacizumab injection in such cases.
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Affiliation(s)
- Machiko Tomida
- Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima
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8
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Enhanced epidermal growth factor, hepatocyte growth factor, and vascular endothelial growth factor expression in tuberous sclerosis complex. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 178:296-305. [PMID: 21224066 DOI: 10.1016/j.ajpath.2010.11.031] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 08/03/2010] [Accepted: 09/21/2010] [Indexed: 12/28/2022]
Abstract
Epidermal growth factor (EGF), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF) regulate angiogenesis and cell growth in the developing brain. EGF, HGF, and VEGF modulate the activity of the mammalian target of rapamycin (mTOR) cascade, a pathway regulating cell growth that is aberrantly activated in tuberous sclerosis complex (TSC). We hypothesized that expression of EGF, HGF, VEGF, and their receptors EGFR, c-Met, and Flt-1, respectively, would be altered in TSC. We show by cDNA array and immunohistochemical analysis that EGF, EGFR, HGF, c-Met, and VEGF, but not Flt-1, mRNA, and protein expression was up-regulated in Tsc1 conditional knockout (Tsc1(GFAP)CKO) mouse cortex. Importantly, these alterations closely predicted enhanced expression of these proteins in tuber and subependymal giant cell astrocytoma (SEGA) specimens in TSC. Expression of EGF, EGFR, HGF, c-Met, and VEGF protein, as well as hypoxia inducible factor-1α, a transcription factor that regulates VEGF levels and is also modulated by mTOR cascade activity, was enhanced in SEGAs (n = 6) and tubers (n = 10) from 15 TSC patients. Enhanced expression of these growth factors and growth factor receptors in human SEGAs and tubers and in the Tsc1(GFAP)CKO mouse may account for enhanced cellular growth and proliferation in tubers and SEGAs and provides potential target molecules for therapeutic development in TSC.
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Darling TN, Pacheco-Rodriguez G, Gorio A, Lesma E, Walker C, Moss J. Lymphangioleiomyomatosis and TSC2-/- cells. Lymphat Res Biol 2010; 8:59-69. [PMID: 20235888 DOI: 10.1089/lrb.2009.0031] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The cells comprising pulmonary lymphangioleiomyomatosis (LAM) and renal angiomyolipomas (AMLs) are heterogeneous, with variable mixtures of cells exhibiting differentiation towards smooth muscle, fat, and vessels. Cells grown from LAM and AMLs have likewise tended to be heterogeneous. The discovery that LAM and AMLs contain cells with mutations in the TSC1 or TSC2 genes is allowing investigators to discriminate between "two-hit" cells and neighboring cells, providing insights into disease pathogenesis. In rare cases, it has been possible to derive cells from human tumors, including AMLs and TSC skin tumors that are highly enriched for TSC2(-/-) cells. Cells derived from an Eker rat uterine leiomyoma (ELT3 cells) are Tsc2-null and these have been used in a rodent cell models for LAM. Further improvements in the ability to reliably grow well-characterized TSC2(-/-) cells from human tumors are critical to developing in vitro and in vivo model systems for studies of LAM pathogenesis and treatment.
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Affiliation(s)
- Thomas N Darling
- Department of Dermatology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.
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10
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Glasgow CG, Taveira-DaSilva A, Pacheco-Rodriguez G, Steagall WK, Tsukada K, Cai X, El-Chemaly S, Moss J. Involvement of lymphatics in lymphangioleiomyomatosis. Lymphat Res Biol 2010; 7:221-8. [PMID: 20143921 DOI: 10.1089/lrb.2009.0017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Lymphangioleiomyomatosis (LAM), a rare multisystem disease, occurs primarily in women, with cystic destruction of the lungs, abdominal tumors, and involvement of the axial lymphatics in the thorax and abdomen. To understand the pathogenesis of LAM, we initiated a longitudinal study of patients with LAM; over 500 patients have been enrolled. LAM results from the proliferation of a neoplastic cell (LAM cell), which has mutations in the tuberous sclerosis complex (TSC) genes, TSC1 or TSC2. Consistent with their metastatic behavior, LAM cells were isolated from blood, urine, and chylous effusions. Surface proteins on LAM cells include those found on metastatic cells and those involved in cell migration. In the lung, LAM cells are found clustered in nodules, which appear in the walls of the cysts, and in the interstitium. LAM lung nodules are traversed by slit-like vascular structures, with lining cells showing reactivity with antibodies against components of lymphatic endothelial cells. The axial lymphatics appear to be infiltrated by LAM cells, which may result in obstruction and formation of chyle-filled lymphangioleiomyomas. LAM cell clusters have been isolated from chylous pleural effusions, and it is hypothesized that these clusters may be responsible for metastatic spread of LAM cells via lymphatic vessels. Consistent with a lymphangiogenic process, levels of VEGF-D, a lymphangiogenic factor, were higher in sera of patients with LAM and lymphatic involvement (i.e., lymphangioleiomyoma, adenopathy) than in healthy volunteers or LAM patients with cystic disease limited to the lung. These findings are consistent with an important function for lymphangiogenesis in LAM.
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Affiliation(s)
- Connie G Glasgow
- Translational Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1590, USA
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Saito W, Kase S, Ohgami K, Mori S, Ohno S. Intravitreal anti-vascular endothelial growth factor therapy with bevacizumab for tuberous sclerosis with macular oedema. Acta Ophthalmol 2010; 88:377-80. [PMID: 18778334 DOI: 10.1111/j.1755-3768.2008.01331.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To describe two patients with macular oedema secondary to tuberous sclerosis complex (TSC) who were treated with intravitreal bevacizumab injection. METHODS Interventional case reports. Bevacizumab 1.25 mg was injected into the vitreous of two patients with TSC-associated macular oedema / exudative retinal detachment. Vascular endothelial growth factor (VEGF) concentration in the vitreous fluid was measured by enzyme-linked immunosorbent assay (ELISA) in one of these patients. RESULTS Patient 1: a 22-year-old woman with TSC was diagnosed as having multiple retinal hamartomas in both eyes. Eleven years later, the patient developed macular oedema with epiretinal membrane formation in the right eye. The patient underwent pars-plana vitrectomy with retinal photocoagulation for retinal tumours. VEGF concentration in the vitreous fluid was high compared to that in patients without retinal vascular diseases. Recurrent macular oedema disappeared by intravitreal injection of bevacizumab. Patient 2: a 32-year-old woman with TSC-associated retinal hamartoma, temporally showing macular exudative retinal detachment, developed neovascularization originated from the tumour. By intravitreal bevacizumab injection, the tumour size reduced markedly with regression of neovascularization. CONCLUSION These results suggest that VEGF derived from retinal hamartomas causes macular oedema associated with TSC. Intravitreal injections of bevacizumab may be a useful therapeutic option for macular oedema secondary to TSC.
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12
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Mahimainathan L, Ghosh-Choudhury N, Venkatesan B, Das F, Mandal CC, Dey N, Habib SL, Kasinath BS, Abboud HE, Ghosh Choudhury G. TSC2 deficiency increases PTEN via HIF1alpha. J Biol Chem 2009; 284:27790-27798. [PMID: 19648120 DOI: 10.1074/jbc.m109.028860] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Substantial evidence suggests roles of TSC2 and PTEN in the development of cancer predisposition syndromes. Loss of TSC2 results in benign tumors, neurological disorders, and angiomyolipomas. We found that PTEN mRNA and protein levels are elevated in Tsc2(-/-) mouse embryo fibroblasts with concomitant reduction in Akt phosphorylation. Reconstitution of TSC2 in Tsc2(-/-) mouse embryo fibroblasts decreases PTEN levels. Interestingly, increased HIF1alpha activity present in Tsc2 null cells is required for PTEN transcription and protein expression. We identified a canonical hypoxia-responsive element in the PTEN promoter, which regulates the transcription of this tumor suppressor protein in a TSC2-dependent manner. Finally, we demonstrate a positive correlation between expression of HIF1alpha and PTEN in renal angiomyolipomas from TSC patients. Our results reveal a unique function of HIF1alpha in up-regulation of PTEN and provide a new mechanism of reduced Akt phosphorylation in Tsc2 null cells. These data suggest that PTEN may safeguard against developing malignant tumors in patients with TSC deficiency.
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Affiliation(s)
- Lenin Mahimainathan
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Nandini Ghosh-Choudhury
- Veterans Affairs Research, South Texas Veterans Health Care System, San Antonio, Texas 78229; Department of Pathology, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Balachandar Venkatesan
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Falguni Das
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Chandi C Mandal
- Department of Pathology, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Nirmalya Dey
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Samy L Habib
- Veterans Affairs Research, South Texas Veterans Health Care System, San Antonio, Texas 78229; Geriatric Research, Education, and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas 78229
| | - Balakuntalam S Kasinath
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229-3900; Veterans Affairs Research, South Texas Veterans Health Care System, San Antonio, Texas 78229
| | - Hanna E Abboud
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229-3900; Veterans Affairs Research, South Texas Veterans Health Care System, San Antonio, Texas 78229
| | - Goutam Ghosh Choudhury
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229-3900; Veterans Affairs Research, South Texas Veterans Health Care System, San Antonio, Texas 78229; Geriatric Research, Education, and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas 78229.
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Glasgow CG, Taveira-Dasilva AM, Darling TN, Moss J. Lymphatic involvement in lymphangioleiomyomatosis. Ann N Y Acad Sci 2008; 1131:206-14. [PMID: 18519973 DOI: 10.1196/annals.1413.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Lymphangioleiomyomatosis (LAM) is a rare, multisystem disease affecting primarily premenopausal women. The disease is characterized by cystic lung disease, at times leading to respiratory compromise, abdominal tumors (in particular, renal angiomyolipomas), and involvement of the axial lymphatics (e.g., adenopathy, lymphangioleiomyomas). Disease results from the proliferation of neoplastic cells (LAM cells), which, in many cases, have a smooth muscle cell phenotype, express melanoma antigens, and have mutations in one of the tuberous sclerosis complex genes (TSC1 or TSC2). In the lung, LAM cells found in the vicinity of cysts are, at times, localized in nodules and may be responsible for cyst formation through the production of proteases. Lymphatic channels, expressing characteristic lymphatic endothelial cell markers, are found within the LAM lung nodules. LAM cells may also be localized within the walls of the axial lymphatics, and, in some cases, penetrate the wall and proliferate in the surrounding adipose tissue. Consistent with extensive lymphatic involvement in LAM, the serum concentration of VEGF-D, a lymphangiogenic factor, is higher in LAM patients than in healthy volunteers.
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Affiliation(s)
- Connie G Glasgow
- Translational Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bldg. 10, Rm. 6D03 MSC 1590, Bethesda, MD 20892-1590, USA
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14
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Mesenchymal-epithelial interactions involving epiregulin in tuberous sclerosis complex hamartomas. Proc Natl Acad Sci U S A 2008; 105:3539-44. [PMID: 18292222 DOI: 10.1073/pnas.0712397105] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Patients with tuberous sclerosis complex (TSC) develop hamartomas containing biallelic inactivating mutations in either TSC1 or TSC2, resulting in mammalian target of rapamycin (mTOR) activation. Hamartomas overgrow epithelial and mesenchymal cells in TSC skin. The pathogenetic mechanisms for these changes had not been investigated, and the existence or location of cells with biallelic mutations ("two-hit" cells) was unclear. We compared TSC skin hamartomas (angiofibromas and periungual fibromas) with normal-appearing skin of the same patient, and we observed more proliferation and mTOR activation in hamartoma epidermis. Two-hit cells were not detected in the epidermis. Fibroblast-like cells in the dermis, however, exhibited allelic deletion of TSC2, in both touch preparations of fresh tumor samples and cells grown from TSC skin tumors, suggesting that increased epidermal proliferation and mTOR activation were not caused by second-hit mutations in the keratinocytes but by mesenchymal-epithelial interactions. Gene expression arrays, used to identify potential paracrine factors released by mesenchymal cells, revealed more epiregulin mRNA in fibroblast-like angiofibroma and periungual fibroma cells than in fibroblasts from normal-appearing skin of the same patient. Elevation of epiregulin mRNA was confirmed with real-time PCR, and increased amounts of epiregulin protein were demonstrated with immunoprecipitation. Epiregulin stimulated keratinocyte proliferation and phosphorylation of ribosomal protein S6 in vitro. These results suggest that hamartomatous TSC skin tumors are induced by paracrine factors released by two-hit cells in the dermis and that proliferation with mTOR activation of the overlying epidermis is an effect of epiregulin.
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15
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Abstract
The missed mark or hamartia underlying each hamartoma syndrome is a mutation in a tumor suppressor gene. This sets the stage for the development of frequent and early tumors in multiple organs. Loss of function of the tumor suppressor in neoplastic cells leads to dysregulation of signaling pathways and tumor growth. The convergence of these signaling pathways to the mTOR pathway suggests that rapamycin or rapamycin-like drugs have potential for treatment, perhaps in combination with drugs targeting other signaling pathways. Haploinsufficient cells also play significant roles in tumor formation. Disrupting interactions between neoplastic cells and surrounding haploinsufficient cells using antiangiogenesis therapies represent an additional approach for treatment. It is hoped that the debilitating effects of these syndromes soon will be alleviated or even reversed though targeted therapies.
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Affiliation(s)
- Thomas N Darling
- Department of Dermatology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
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16
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Seyama K, Kumasaka T, Souma S, Sato T, Kurihara M, Mitani K, Tominaga S, Fukuchi Y. Vascular endothelial growth factor-D is increased in serum of patients with lymphangioleiomyomatosis. Lymphat Res Biol 2006; 4:143-52. [PMID: 17034294 DOI: 10.1089/lrb.2006.4.143] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Lymphangioleiomyomatosis (LAM) is a rare destructive lung disease characterized by an abnormal proliferation of smooth muscle-like cells (LAM cells) in the lung and along the axial lymphatics. LAM demonstrates a heterogeneous clinical course, but there is no serum surrogate marker available for assessing the disease severity or predicting the disease progression. Since the authors have recently demonstrated the extensive LAM-associated lymphangiogenesis and its potential role in progression and metastasis of LAM cells, they hypothesized that serum levels of lymphangiogenic growth factors might be increased in LAM and become a surrogate marker for disease severity. METHODS AND RESULTS VEGF-A, VEGF-C, and VEGF-D in serum of 44 patients with LAM were measured by enzyme-linked immunosorbant assay. Only VEGF-D was significantly increased in LAM patients as compared with age- and gender-matched healthy volunteers (n=24) (LAM vs. control, geometric mean 95% CI; 1069.3 pg/mL (809.4 approximately 1412.6) vs. 295.9 pg/mL (262.6 approximately 333.5), p<0.0001). Serum VEGF-D levels negatively correlated with variables of pulmonary function tests, FEV1/FVC (forced expiratory volume in one second/forced vital capacity) (r=-0.365, p<0.05) and %DLco/VA (the percentage of diffusing capacity for carbon monoxide/alveolar volume to the predicted value) (r=-0.560, p<0.001). As expected, the group who received hormone therapy showed more deteriorated pulmonary function with higher serum VEGF-D levels than the group who was just observed without hormone therapy. Immunohistochemical examination of lung specimens demonstrated the positive immunoreactivity of LAM cells for VEGF-D. CONCLUSION Serum VEGF-D levels may be a valuable surrogate marker for evaluating the disease severity in LAM.
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Affiliation(s)
- Kuniaki Seyama
- Department of Respiratory Medicine, Juntendo University, School of Medicine, and Pneumothorax Center, Nissan Tamagawa Hospital, Tokyo, Japan.
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17
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Jiang WG, Sampson J, Martin TA, Lee-Jones L, Watkins G, Douglas-Jones A, Mokbel K, Mansel RE. Tuberin and hamartin are aberrantly expressed and linked to clinical outcome in human breast cancer: the role of promoter methylation of TSC genes. Eur J Cancer 2005; 41:1628-36. [PMID: 15951164 DOI: 10.1016/j.ejca.2005.03.023] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 03/23/2005] [Accepted: 03/29/2005] [Indexed: 11/17/2022]
Abstract
PURPOSE The tuberous sclerosis (TSC) genes TSC1 and TSC2 encode the protein products hamartin and tuberin, respectively, and are putative tumour suppressor genes. Germ-line mutation of either TSC gene leads to the development of the heritable disorder TSC. This disorder is characterized by the development of hamartomas in many organs and is associated with the proliferative lung disease, lymphangioleiomyomatosis, the brain tumour giant cell astrocytoma and occasionally with renal cell carcinoma. However, the TSC genes have not been studied in breast cancer. The current study investigated the expression of the TSC gene products and the potential mechanisms of their aberrancy in human breast cancer cells and tissues. EXPERIMENTAL DESIGN AND RESULTS Using immunohistochemical analysis, both hamartin and tuberin were found to be strongly stained in normal mammary epithelial cells and weakly in stromal cells. In invasive tumour tissues, however, the staining of both proteins were to be markedly reduced (P < 0.01). At message level, although normal and tumour tissues expressed both TSC products, the transcript levels of tuberin was significantly lower in tumour tissues compared with normal tissues (P < 0.05). There was no statistical difference between node negative and node positive tumours with both hamartin and tuberin. Tumours from patients who developed recurrence and died from breast cancer had significantly low levels of tuberin compared with those who remained disease free (P = 0.03 and 0.05, respectively). Likewise, hamartin levels were significantly lower in patients with metastasis, recurrence and mortality, when compared with those remained disease free (P = 0.001, 0.041 and 0.003, respectively). Using methylation specific PCR, the TSC1 promoter was found to be heavily methylated in ZR751, MDA MB 435, and BT549, but not in MCF-7 which expressed highly level of hamartin. TSC1 promoter methylation was also seen in most breast tumours, but only in a limited number of normal tissues. The methylation of TSC2 promoter appears to be less frequent. MDA MB 468, MDA MB 483, MDA MB 435S and weakly MDA MB 435 were found to have methylated TSC2 promoter. In breast tissues, however, a very small number of samples were found to have methylation of the TSC2 promoter. CONCLUSION TSC1 genes are aberrantly expressed in human breast cancer cell lines and breast tumour tissues and their promoters are seen to be methylated in breast tumour tissues. The expression of TSC1 is associated with an unfavourable clinical outcome in patients with breast cancer.
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Affiliation(s)
- Wen G Jiang
- Metastasis and Angiogenesis Research Group, University Department of Surgery, Wales College of Medicine, Cardiff University, UK.
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18
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Li S, Takeuchi F, Wang JA, Fuller C, Pacheco-Rodriguez G, Moss J, Darling TN. MCP-1 overexpressed in tuberous sclerosis lesions acts as a paracrine factor for tumor development. ACTA ACUST UNITED AC 2005; 202:617-24. [PMID: 16129702 PMCID: PMC1378109 DOI: 10.1084/jem.20042469] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Patients with tuberous sclerosis complex (TSC) develop hamartomatous tumors showing loss of function of the tumor suppressor TSC1 (hamartin) or TSC2 (tuberin) and increased angiogenesis, fibrosis, and abundant mononuclear phagocytes. To identify soluble factors with potential roles in TSC tumorigenesis, we screened TSC skin tumor–derived cells for altered gene and protein expression. Fibroblast-like cells from 10 angiofibromas and five periungual fibromas produced higher levels of monocyte chemoattractant protein-1 (MCP-1) mRNA and protein than did fibroblasts from the same patient's normal skin. Conditioned medium from angiofibroma cells stimulated chemotaxis of a human monocytic cell line to a greater extent than conditioned medium from TSC fibroblasts, an effect blocked by neutralizing MCP-1–specific antibody. Overexpression of MCP-1 seems to be caused by loss of tuberin function because Eker rat embryonic fibroblasts null for Tsc2 (EEF Tsc2−/−) produced 28 times as much MCP-1 protein as did EEF Tsc2+/+ cells; transient expression of WT but not mutant human TSC2 by EEF Tsc2−/− cells inhibited MCP-1 production; and pharmacological inhibition of the Rheb-mTOR pathway, which is hyperactivated after loss of TSC2, decreased MCP-1 production by EEF Tsc2−/− cells. Together these findings suggest that MCP-1 is an important paracrine factor for TSC tumorigenesis and may be a new therapeutic target.
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Affiliation(s)
- Shaowei Li
- Department of Dermatology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Baybis M, Yu J, Lee A, Golden JA, Weiner H, McKhann G, Aronica E, Crino PB. mTOR cascade activation distinguishes tubers from focal cortical dysplasia. Ann Neurol 2004; 56:478-87. [PMID: 15455405 DOI: 10.1002/ana.20211] [Citation(s) in RCA: 196] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Balloon cells (BCs) in focal cortical dysplasia (FCD) and giant cells (GCs) in tubers of the tuberous sclerosis complex (TSC) share phenotypic similarities. TSC1 or TSC2 gene mutations in TSC lead to mTOR pathway activation and p70S6kinase (phospho-S6K) and ribosomal S6 (phospho-S6) protein phosphorylation. Phospho-S6K, phospho-S6, and phospho-S6K-activated proteins phospho-STAT3 and phospho-4EBP1 were detected immunohistochemically in GCs, whereas only phospho-S6 was observed in BCs. Expression of four candidate gene families (cell signaling, cell adhesion, growth factor/receptor, and transcription factor mRNAs) was assayed in single, microdissected phospho-S6-immunolabeled BCs and GCs as a strategy to define whether BCs and GCs exhibit differential transcriptional profiles. Among 60 genes, differential expression of 24 mRNAs distinguished BCs from GCs and only 4 genes showed similar expression profiles between BCs and GCs. Tuberin mRNA levels were reduced in GCs from TSC patients with TSC2 gene mutations but were unchanged in BCs. Phospho-S6K, -S6, -STAT3, and -4EBP1 expression in GCs reflects loss of hamartin-tuberin-mediated mTOR pathway inhibition. Phospho-S6 expression alone in BCs does not support mTOR cascade activation in FCD. Differential gene expression profiles in BCs and GCs supports the hypothesis that these cell types derive by distinct pathogenic mechanisms.
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Affiliation(s)
- Marianna Baybis
- PENN Epilepsy Center and Department of Neurology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
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20
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Brugarolas J, Lei K, Hurley RL, Manning BD, Reiling JH, Hafen E, Witters LA, Ellisen LW, Kaelin WG. Regulation of mTOR function in response to hypoxia by REDD1 and the TSC1/TSC2 tumor suppressor complex. Genes Dev 2004; 18:2893-904. [PMID: 15545625 PMCID: PMC534650 DOI: 10.1101/gad.1256804] [Citation(s) in RCA: 1019] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a central regulator of protein synthesis whose activity is modulated by a variety of signals. Energy depletion and hypoxia result in mTOR inhibition. While energy depletion inhibits mTOR through a process involving the activation of AMP-activated protein kinase (AMPK) by LKB1 and subsequent phosphorylation of TSC2, the mechanism of mTOR inhibition by hypoxia is not known. Here we show that mTOR inhibition by hypoxia requires the TSC1/TSC2 tumor suppressor complex and the hypoxia-inducible gene REDD1/RTP801. Disruption of the TSC1/TSC2 complex through loss of TSC1 or TSC2 blocks the effects of hypoxia on mTOR, as measured by changes in the mTOR targets S6K and 4E-BP1, and results in abnormal accumulation of Hypoxia-inducible factor (HIF). In contrast to energy depletion, mTOR inhibition by hypoxia does not require AMPK or LKB1. Down-regulation of mTOR activity by hypoxia requires de novo mRNA synthesis and correlates with increased expression of the hypoxia-inducible REDD1 gene. Disruption of REDD1 abrogates the hypoxia-induced inhibition of mTOR, and REDD1 overexpression is sufficient to down-regulate S6K phosphorylation in a TSC1/TSC2-dependent manner. Inhibition of mTOR function by hypoxia is likely to be important for tumor suppression as TSC2-deficient cells maintain abnormally high levels of cell proliferation under hypoxia.
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Affiliation(s)
- James Brugarolas
- Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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21
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Abstract
The study of hereditary tumor syndromes has laid a solid foundation toward understanding the genetic basis of cancer. One of the latest examples comes from the study of tuberous sclerosis complex (TSC). As a member of the phakomatoses, TSC is characterized by the appearance of benign tumors, most notably in the central nervous system, kidney, heart, lung, and skin. While classically described as "hamartomas," the pathology of the lesions has features suggestive of abnormal cellular proliferation, size, differentiation, and migration. Occasionally, tumors progress to become malignant (i.e., renal cell carcinoma). The genetic basis of this disease has been attributed to mutations in one of two unlinked genes, TSC1 and TSC2. Cells undergo bi-allelic inactivation of either gene to give rise to tumors in a classic tumor suppressor "two-hit" paradigm. The functions of the TSC1 and TSC2 gene products, hamartin and tuberin, respectively, have remained ill defined until recently. Genetic, biochemical, and biologic analyses have highlighted their role as negative regulators of the mTOR signaling pathway. Tuberin, serving as a substrate of AKT and AMPK, mediates mTOR activity by coordinating inputs from growth factors and energy availability in the control of cell growth, proliferation, and survival. Emerging evidence also suggests that the TSC 1/2 complex may play a role in modulating the activity of beta-catenin and TGFbeta. These findings provide novel functional links between the TSC genes and other tumor suppressors responsible for Cowden's disease (PTEN), Peutz-Jeghers syndrome (LKB1), and familial polyposis (APC). Common sporadic cancers such as prostate, lung, colon, endometrium, and breast have ties to these genes, highlighting the potential role of the TSC proteins in human cancers. Rapamycin, a specific mTOR inhibitor, has potent antitumoral activities in preclinical models of TSC and is currently undergoing phase I/II clinical studies.
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Affiliation(s)
- Baldwin C Mak
- Department of Surgery, University of Washington, Seattle, Washington 98195, USA
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22
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Kumasaka T, Seyama K, Mitani K, Sato T, Souma S, Kondo T, Hayashi S, Minami M, Uekusa T, Fukuchi Y, Suda K. Lymphangiogenesis in Lymphangioleiomyomatosis. Am J Surg Pathol 2004; 28:1007-16. [PMID: 15252306 DOI: 10.1097/01.pas.0000126859.70814.6d] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Lymphangioleiomyomatosis (LAM) is characterized by the proliferation of abnormal smooth muscle cells (LAM cells) in the lungs, lymph nodes, and/or other organs. We examined lymphangiogenesis using immunohistochemistry for Flt-4 (VEGFR-3), a new specific marker for lymphatic endothelial cells, as well as the expression of vascular endothelial growth factor (VEGF)-C in LAM. Specimens were obtained from 6 autopsy cases, a single lung transplant case, and 8 surgical cases for analyses. We demonstrated that lymphatics were extremely abundant in both pulmonary and extrapulmonary LAM and that lymphatic endothelial cells not only proliferated encompassing LAM foci but also infiltrated the intra-LAM foci, and that in advanced LAM, lymphangiogenesis involved vascular walls and interstitium surrounding the area where LAM cells proliferate. In contrast, angiogenesis, confirmed with CD31 immunostaining, was observed less in the LAM foci. LAM cells demonstrated positive reactivity against anti-VEGF-C antibody at varying intensities. Significant correlation (P < 0.001) was noted between the degree of lymphangiogenesis in LAM or VEGF-C expression on LAM cells and lymphagioleiomyomatosis histologic score (LHS), which represents the histologic severity of pulmonary LAM and has been reported to have prognostic significance. Our study is likely to provide a novel point of view on the pathophysiologic significance of lymphangiogenesis in LAM.
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Affiliation(s)
- Toshio Kumasaka
- Department of Pathology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 13-8421, Japan.
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23
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Abstract
The LKB1 tumor suppressor protein controls the activity of the TSC1/TSC2 tumor suppressor complex. Mutations in LKB1 cause Peutz-Jeghers syndrome (PJS), and mutations in either TSC1 or TSC2 cause tuberous sclerosis complex--two syndromes characterized by the development of hamartomas. LKB1 activation by energy deprivation activates AMPK, which in turn phosphorylates and activates TSC2. TSC2 activation results in the inactivation of mTOR, a critical regulator of protein translation. How mTOR dysregulation after inactivation of LKB1 or TSC1/2 contributes to hamartoma development is not known. However, hypoxia-inducible factor (HIF) and VEGF are regulated by mTOR and are likely to play a contributory role.
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Affiliation(s)
- James Brugarolas
- Dana-Farber Cancer Institute and Harvard Medical School, Howard Hughes Medical Institute, 44 Binney Street, Mayer 457, Boston, Massachusetts 02115, USA
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Han S, Santos TM, Puga A, Roy J, Thiele EA, McCollin M, Stemmer-Rachamimov A, Ramesh V. Phosphorylation of tuberin as a novel mechanism for somatic inactivation of the tuberous sclerosis complex proteins in brain lesions. Cancer Res 2004; 64:812-6. [PMID: 14871804 DOI: 10.1158/0008-5472.can-03-3277] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tuberous sclerosis complex is caused by mutations in tumor suppressor genes TSC1 or TSC2 and is characterized by the presence of hamartomas in many organs. Although tuberous sclerosis complex is a tumor suppressor gene syndrome with classic "second hits" detectable in renal tumors, conventional genetic analysis has not revealed somatic inactivation of the second allele in the majority of human brain lesions. We demonstrate a novel mechanism of post-translational inactivation of the TSC2 protein, tuberin, by physiologically inappropriate phosphorylation, which is specific to tuberous sclerosis complex-associated brain lesions. Additional analysis shows that tissue specificity is due to abnormal activation of the Akt and mitogen-activated protein kinase pathways in brain but not in renal tumors. These results have widespread implications for understanding the tissue specificity of tumor suppressor gene phenotypes.
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Affiliation(s)
- Sangyeul Han
- Molecular Neurogenetics Unit, Molecular Neuro-Oncology, and Department of Neurology, Harvard Medical School/Massachusetts General Hospital, Charlestown, Massachusetts, USA
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25
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Maynard MA, Ohh M. Von Hippel-Lindau tumor suppressor protein and hypoxia-inducible factor in kidney cancer. Am J Nephrol 2004; 24:1-13. [PMID: 14654728 DOI: 10.1159/000075346] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2003] [Accepted: 10/20/2003] [Indexed: 12/31/2022]
Abstract
The development of hereditary von Hippel-Lindau (VHL) disease and the majority of sporadic kidney cancers are due to the functional inactivation of the VHL gene. The product of the VHL gene, pVHL, in association with elongins B and C, cullin 2, and Rbx1 form an E3 ubiquitin-ligase complex VEC that targets the alpha subunits of hypoxia-inducible factor (HIF) for ubiquitination. Ubiquitin-tagged HIF-alpha proteins are subsequently degraded by the common 26S proteasome. pVHL functions as the substrate-docking interface that specifically recognizes prolyl-hydroxylated HIF-alpha. This hydroxylation occurs only in the presence of oxygen or normoxia. Thus, under hypoxia, HIF-alpha subunits are no longer subjected to degradation and are thereby able to dimerize with the common and constitutively stable beta subunits. The heterodimeric HIFs upregulate a myriad of hypoxia-inducible genes, triggering our physiologic response to hypoxia. Inappropriate accumulations of HIF-alpha in VHL disease are believed to contribute to the pathogenesis via the upregulation of several of these HIF target genes. Our current molecular understanding of the roles of HIF and pVHL in the development of VHL-associated clear-cell renal cell carcinoma (CC-RCC) is the focus of this review.
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Affiliation(s)
- Mindy A Maynard
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ont., Canada
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26
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Abstract
Soon after proposing the "two-hit" hypothesis for tumorigenesis, Knudson pursued further experimental validation of the concept by using a rat model of dominantly inherited renal tumor. Today, the Eker rat is one of the best characterized models of tuberous sclerosis complex (TSC) and has been used extensively for study of the function of the TSC2 tumor suppressor gene. Along with TSC1, these two genes behave as expected for tumor suppressor genes with evidence for loss of heterozygosity in tumors and suppression of growth when expressed in proliferating cells. Despite much experimental work, the mechanisms of these genes have remained elusive until recently. This review summarizes some of the current concepts in our understanding of the biological and biochemical function of the TSC genes.
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Affiliation(s)
- Raymond S Yeung
- Department of Surgery, University of Washington, Seattle, Washington, USA.
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Brugarolas JB, Vazquez F, Reddy A, Sellers WR, Kaelin WG. TSC2 regulates VEGF through mTOR-dependent and -independent pathways. Cancer Cell 2003; 4:147-58. [PMID: 12957289 DOI: 10.1016/s1535-6108(03)00187-9] [Citation(s) in RCA: 406] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Inactivation of the TSC2 tumor suppressor protein causes tuberous sclerosis complex (TSC), a disease characterized by highly vascular tumors. TSC2 has multiple functions including inhibition of mTOR (mammalian target of Rapamycin). We found that TSC2 regulates VEGF through mTOR-dependent and -independent pathways. TSC2 loss results in the accumulation of HIF-1alpha and increased expression of HIF-responsive genes including VEGF. Wild-type TSC2, but not a disease-associated TSC2 mutant, downregulates HIF. Rapamycin normalizes HIF levels in TSC2(-/-) cells, indicating that TSC2 regulates HIF by inhibiting mTOR. In contrast, Rapamycin only partially downregulates VEGF in this setting, implying an mTOR-independent link between TSC2 loss and VEGF. This pathway may involve chromatin remodeling since the HDAC inhibitor Trichostatin A downregulates VEGF in TSC2(-/-) cells.
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Affiliation(s)
- James B Brugarolas
- Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA
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Abstract
PURPOSE Tuberous sclerosis is an autosomal dominant neurocutaneous syndrome affecting multiple organ systems and demonstrating highly variable clinical manifestations. Mutations in 2 tumor suppressor genes, TSC1 and TSC2, are linked to the evolution of the hamartomatous lesions. We describe the incidence and epidemiology, variable clinical manifestations and their relationships to renal pathology, and the management of morbid sequelae. MATERIALS AND METHODS Using the search term tuberous sclerosis, we performed a MEDLINE search of the literature identifying 3,196 articles and selected those from urological, surgical, oncological, genetic and pediatric journals. Special focus was placed on the incidence and management of renal lesions and on different clinical manifestations and how they relate to renal tumors. RESULTS Due to improved identification of the variable phenotypic expression, the reported incidence has increased. TSC1 and TSC2 mutations are related to various phenotypic manifestations and risks of malignancy, such as an increased incidence of the TSC2 mutation in patients with renal cell carcinoma. Renal sparing surgery and selective embolization techniques have mitigated the morbidity of the lesions. CONCLUSIONS We now have a better understanding of the variability at the genotypic and phenotypic levels of the disease. We recommend that patients with tuberous sclerosis complex be evaluated by a multidisciplinary group of clinicians, including urologists, dermatologists, neurologists, pediatricians and geneticists. Close attention to these manifestations is necessary to ensure appropriate treatment of the sequelae of the tuberous sclerosis complex.
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Affiliation(s)
- Thomas S Lendvay
- Department of Urology, Emory University School of Medicine, Atlanta, GA, USA
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Fackler I, DeClue JE, Rust H, Vu PA, Kutzner H, Rütten A, Kaddu S, Sander CA, Volkenandt M, Johnson MW, Vinters HV, Wienecke R. Loss of expression of tuberin and hamartin in tuberous sclerosis complex-associated but not in sporadic angiofibromas. J Cutan Pathol 2003; 30:174-7. [PMID: 12641776 DOI: 10.1034/j.1600-0560.2003.2o066.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Angiofibromas occur sporadically, and they develop in most patients with tuberous sclerosis complex (TSC), which is associated with alterations of the tumor suppressor genes TSC1 or TSC2. Loss of tuberin, the protein product of TSC2, has been shown in the interstitial fibroblast compartment of TSC-associated angiofibromas. It is unclear whether there is also a loss of hamartin, the product of TSC1 in TSC-associated and sporadic angiofibromas. METHODS The expression of hamartin and tuberin was analyzed by immunohistochemistry in 59 TSC-associated and 12 sporadic angiofibromas using affinity-purified antibodies. RESULTS Loss of expression of both tuberin and hamartin was detected in 14 angiofibromas, loss of only tuberin in three, and loss of only hamartin in four TSC-associated angiofibromas; but there was no loss in the sporadic angiofibromas. Only the interstitial cells, but not the vascular cells, showed a loss of expression of tuberin or hamartin. CONCLUSIONS Loss of tuberin or hamartin occurred in a minority of the TSC-linked angiofibromas, but not in the sporadic angiofibromas. The absence of both tuberin and hamartin in some of the tumors suggests that the stability of tuberin and hamartin, which are believed to form an active complex in vivo, is negatively affected by the absence of either of the partners.
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Affiliation(s)
- Ingrid Fackler
- Department of Dermatology, Ludwig-Maximilians-University Munich, Munich, Germany
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Hockenbery DM. Nailing down a link between tuberin and renal cysts. THE AMERICAN JOURNAL OF PATHOLOGY 2003; 162:369-71. [PMID: 12547695 PMCID: PMC1851147 DOI: 10.1016/s0002-9440(10)63831-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- David M Hockenbery
- Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.
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Wienecke R, Klemm E, Karparti S, Swanson NA, Green AJ, DeClue JE. Reduction of expression of tuberin, the tuberous-sclerosis-complex-gene-2 product in tuberous sclerosis complex associated connective tissue nevi and sporadic squamous and basal cell carcinomas. J Cutan Pathol 2002; 29:287-90. [PMID: 12100629 DOI: 10.1034/j.1600-0560.2002.290505.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Patients affected with tuberous sclerosis complex (TSC) are prone to the development of multiple benign tumors of the skin and other organs. Tuberin, the protein product of the tuberous-sclerosis-complex-2 tumor suppressor gene (TSC2) has been shown to inhibit cell proliferation. In TSC associated kidney tumors and sporadic brain tumors the loss/reduction of tuberin has been shown. METHODS Specimens of nine squamous cell carcinomas (SCC) and five basal cell carcinomas (BCC) from patients without TSC and six biopsies of connective tissue nevi (CTN) of patients with TSC were obtained. Specimens were analyzed by immunoblotting for the expression of tuberin. RESULTS Absent or reduced levels of tuberin were detected in the dermal parts of three of six shagreen patches, two of five BCC, and four of nine SCC. CONCLUSIONS In tumors/hamartomas of patients with TSC the complete loss of TSC2 and tuberin is a mechanism which could be shown for CTN, thereby excluding the possibility of haploinsufficiency of TSC2. In a substantial number of cutaneous BCC and SCC the loss or downregulation of tuberin seems to be epigenetic, as alterations of TSC2 are not known in these tumors. The absence or reduction of tuberin might contribute to their proliferation.
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Affiliation(s)
- Ralf Wienecke
- Department of Dermatology and Allergology, Ludwig-Maximilians-University Munich, Munich, Germany.
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