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Epidermal growth factor down‐regulates the expression of neutrophil gelatinase‐associated lipocalin (NGAL) through E‐cadherin in pancreatic cancer cells
Author(s) -
Tong Zhimin,
Chakraborty Subhankar,
Sung Bokyung,
Koolwal Pooja,
Kaur Sukhwinder,
Aggarwal Bharat B.,
Mani Sendurai A.,
Bresalier Robert S.,
Batra Surinder K.,
Guha Sushovan
Publication year - 2010
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.25803
Subject(s) - lipocalin , medicine , cadherin , pancreatic cancer , neutrophil gelatinase associated lipocalin , cancer research , epidermal growth factor , gelatinase , epidermal growth factor receptor , cancer , matrix metalloproteinase , biology , receptor , cell , genetics
BACKGROUND: The authors previously reported that neutrophil gelatinase‐associated lipocalin (NGAL) overexpression significantly blocked invasion and angiogenesis of pancreatic ductal adenocarcinoma (PDAC). They also demonstrated a loss of NGAL expression in the advanced stages of PDAC. However, little is known regarding the mechanisms of NGAL regulation in PDAC. Because the epidermal growth factor (EGF)‐EGF receptor (EGFR) axis is up‐regulated significantly in PDAC, they examined EGF‐mediated NGAL regulation in these cells. METHODS: The NGAL‐positive cell lines AsPC‐1 and BxPC‐3 were used as a model system. Quantitative real‐time polymerase chain reaction (RT‐PCR), Western blot analysis, and immunofluorescence studies were used to investigate EGF‐mediated effects on NGAL expression. E‐cadherin expression was manipulated using lentiviral overexpression or small hairpin RNA constructs. NGAL promoter activity was assessed by luciferase‐reporter assay and electrophoretic mobility shift assay. RESULTS: NGAL expression was positively associated with tumor differentiation and was down‐regulated significantly after EGF treatment along with a concomitant reduction of E‐cadherin expression in PDAC cells. E‐cadherin down‐regulation was partly through the EGFR‐dependent mitogen‐activated protein kinase (MEK)/extracellular signal‐regulated kinase (ERK) (MEK‐ERK) signaling pathway. In addition, E‐cadherin down‐regulation reduced NGAL expression in PDAC cells, whereas overexpression of E‐cadherin led to increased NGAL expression and partly rescued the inhibition of NGAL expression by EGF. Furthermore, EGF, in part through E‐cadherin, reduced NGAL promoter activity by blocking nuclear factor κB (NF‐κB) activation. CONCLUSIONS: The current study demonstrated for the first time that EGF potently blocked NGAL expression in PDAC cells. This effect was mediated in part through activation of the EGFR‐MEK‐ERK signaling pathway, which, in turn, down‐regulated E‐cadherin with a subsequent reduction in NF‐κB activation. These findings illustrate a novel mechanism by which EGF regulates NGAL expression in PDAC. Cancer 2011;. © 2010 American Cancer Society.