Identification of Endoglin as an epigenetically regulated tumour-suppressor gene in lung cancer.
BACKGROUND
The transforming growth factor-beta (TGF- β) pathway has been implicated in proliferation, migration and invasion of various cancers. Endoglin is a TGF-β accessory receptor that modulates signalling. We identified Endoglin as an epigenetically silenced tumour-suppressor gene in lung cancer by means of a genome-wide screening approach, then sought to characterise its effect on lung cancer progression.


METHODS
Methylation microarray and RNA sequencing were carried out on lung cancer cell lines. Epigenetic silencing of Endoglin was confirmed by methylation and expression analyses. An expression vector and a 20-gene expression panel were used to evaluate Endoglin function. Pyrosequencing was carried out on two independent cohorts comprising 112 and 202 NSCLC cases, respectively, and the impact of Endoglin methylation on overall survival (OS) was evaluated.


RESULTS
Methylation in the promoter region resulted in silencing of Endoglin, which could be reactivated by demethylation. Increased invasion coupled with altered EMT marker expression was observed in cell lines with an epithelial-like, but not those with a mesenchymal-like, profile when Endoglin was absent. Methylation was associated with decreased OS in stage I but not in stages II-III disease.


CONCLUSIONS
We show that Endoglin is a common target of epigenetic silencing in lung cancer. We reveal a link between Endoglin silencing and EMT progression that might be associated with decreased survival in stage I disease.
Brighton and Sussex Medical School, University of Sussex, Brighton BN1 9RY, UK.
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K
O'Leary
Brighton and Sussex Medical School, University of Sussex, Brighton BN1 9RY, UK.|Barts Cancer Institute, Queen Mary University of London, Old Anatomy Building, Charterhouse Square, London EC1M 6BQ, UK.
A
A
Shia
Brighton and Sussex Medical School, University of Sussex, Brighton BN1 9RY, UK.
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F
Cavicchioli
Brighton and Sussex Medical School, University of Sussex, Brighton BN1 9RY, UK.
V
V
Haley
Pathology Department, S. Croce General Hospital, via Coppino 26, 12100, Cuneo, Italy.
A
A
Comino
Medical Oncology, Oncology Department, S. Croce General Hospital, via Carle 25, 12100, Cuneo, Italy.
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M
Merlano
Department of Histopathology, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0HS, UK.
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F
Mauri
Oncology Biomarker Development, Genentech, Inc., 550 Grandview Boulevard, South San Francisco, CA 94080, USA.
K
K
Walter
Oncology Biomarker Development, Genentech, Inc., 550 Grandview Boulevard, South San Francisco, CA 94080, USA.
M
M
Lackner
eScience Lab, Department of Biomathematics, University of Bremen, Bremen 28359, Germany.
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MB
Wischnewsky
Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital And Medical School, Dundee DD1 9SY, UK.
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T
Crook
Laboratory of Cancer Genetics and Translational Oncology, Oncology Department, S. Croce Genreal Hospital, via Carle 25, Cuneo 12100, Italy.
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C
Lo Nigro
Brighton and Sussex Medical School, University of Sussex, Brighton BN1 9RY, UK.|Barts Cancer Institute, Queen Mary University of London, Old Anatomy Building, Charterhouse Square, London EC1M 6BQ, UK.
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P
Schmid
D015703:Antigens, CD / Q000235:genetics*; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D045744:Cell Line, Tumor; D018450:Disease Progression; D015536:Down-Regulation; D000071063:Endoglin; D020868:Gene Silencing; D016147:Genes, Tumor Suppressor; D055106:Genome-Wide Association Study; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D008745:Methylation; D011401:Promoter Regions, Genetic; D040081:Protein Array Analysis; D011956:Receptors, Cell Surface / Q000235:genetics*; D017422:Sequence Analysis, DNA / Q000379:methods
D015703:Antigens, CD; C064206:ENG protein, human; D000071063:Endoglin; D011956:Receptors, Cell Surface