Oncogenic role of the E3 ubiquitin ligase NEDD4-1, a PTEN negative regulator, in non-small-cell lung carcinomas.
Loss of the PTEN tumor suppressor gene occurs frequently in non-small-cell lung carcinoma (NSCLC), although neither genetic alterations nor epigenetic silencing are significant predictors of PTEN protein levels. Since recent reports implicated neural precursor cell expressed, developmentally down-regulated 4-1 (NEDD4-1) as the E3 ubiquitin ligase that regulates PTEN stability, we investigated the role of NEDD4-1 in the regulation of PTEN expression in cases of NSCLC. Our findings indicate that NEDD4-1 plays a critical role in the development of NSCLC and provides novel insight on the mechanisms that contribute to inactivate PTEN in lung cancer. Immunohistochemical analysis on tissue microarrays containing 103 NSCLC resections revealed NEDD4-1 overexpression in 80% of tumors, which correlated with the loss of PTEN protein (n=98; P<0.001). Accordingly, adoptive NEDD4-1 expression in NSCLC cells decreased PTEN protein stability, whereas knock-down of NEDD4-1 expression decreased PTEN ubiquitylation and increased PTEN protein levels. In 25% of cases, NEDD4-1 overexpression was due to gene amplification at 15q21. In addition, manipulation of NEDD4-1 expression in different lung cell systems demonstrated that suppression of NEDD4-1 expression significantly reduced proliferation of NSCLC cells in vitro and tumor growth in vivo, whereas NEDD4-1 overexpression facilitated anchorage-dependent and independent growth in vitro of nontransformed lung epithelial cells that lack pRB and TP53 (BEAS-2B). NEDD4-1 overexpression also augmented the tumorigenicity of lung cancer cells that have an intact PTEN gene (NCI-H460 cells).
Amodio
Nicola
N
Department of Experimental and Clinical Medicine, University Magna Graecia, Catanzaro, Italy.
Scrima
Marianna
M
Palaia
Lucia
L
Salman
Ali Naeem
AN
Quintiero
Alfina
A
Franco
Renato
R
Botti
Gerardo
G
Pirozzi
Pino
P
Rocco
Gaetano
G
De Rosa
Nicla
N
Viglietto
Giuseppe
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics / Q000378:metabolism*; D057890:Epigenomics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D046228:Microarray Analysis; D008875:Middle Aged; D000075702:Nedd4 Ubiquitin Protein Ligases; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
D056827:Endosomal Sorting Complexes Required for Transport; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618483:Nedd4 protein, human; D044767:Ubiquitin-Protein Ligases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human