Heterogeneous expression of the lipocalin NGAL in primary breast cancers

Abstract

We have previously shown that neu oncogene-initiated rat mammary carcinomas uniquely over-express neu-related lipocalin (NRL), a member of the calycin protein superfamily. Here, we characterize the putative human homolog of NRL, neutrophil gelatinase-associated lipocalin (NGAL). ngal gene expression was found at moderate levels in only 2 of 17 human tissues examined, breast and lung. When breast cancers were examined for NGAL mRNA and protein levels, they were found to exhibit heterogeneous expression. NGAL levels varied in these tumors from undetectable to exceeding those in normal breast parenchyma. Immuno-histochemical analysis confirmed the presence of NGAL within breast carcinoma cells but detected only low levels of this protein in normal ductal epithelium. In contrast, large amounts of the protein were localized to the lumen of normal breast ducts in the vicinity of NGAL-expressing tumors. Interestingly, unlike NRL in rat mammary carcinomas, no significant association between NGAL expression and HER-2/neu activation was found in human breast tumors. In contrast, a significant correlation between NGAL expression in breast cancer was found with several other markers of poor prognosis, including estrogen and progesterone receptor-negative status and high proliferation (S-phase fraction). NGAL levels were stratified as high or low in breast cancers from a cohort of nodepositive patients with known outcome. No significant association between NGAL expression and disease-free or overall survival was observed. Int. J. Cancer (Pred. Oncol.) 79:565-572, 1998. Wiley-Liss, Inc.The isolation of genes uniquely expressed in a subset of breast cancers has the potential to identify diagnostic markers, prognostic indicators and therapeutic targets. To isolate such over-expressed genes, various model systems have been developed and characterized. For example, 2 in vivo rodent systems have been established to examine mammary carcinomas induced by neu (c-erbB-2/HER-2), the oncogene most commonly associated with the clinical progression of human breast cancer. In the first model, transgenic mice have been generated in which the expression of activated neu is targeted to the mammary gland using mammary-specific promoters (Muller et al., 1988;Bouchard et al., 1989). In the 2nd model, the activated neu oncogene has been directly and stably introduced into in situ rat mammary epithelial cells, using a replicationdefective retroviral vector (Wang et al., 1991a). Using these models, Stoesz and Gould (1995) and others (Morrison and Leder, 1994) have sought to isolate and characterize rodent genes uniquely over-expressed in neu-initiated mammary tumors. To date, using both models, only 1 gene has been cloned which is uniquely over-expressed in mammary tumors induced by neu (Stoesz and Gould, 1995). This gene, termed neu-related lipocalin (nrl), is 12-fold over-expressed in rat neu-initiated carcinomas but is not over-expressed in ras-initiated mammary carcinomas or in mammary tumors induced with chemical carcinogens. In addition, this ...

Early diagnosis of pancreatic cancer: neutrophil gelatinase-associated lipocalin as a marker of pancreatic intraepithelial neoplasia

“…Blotted membranes were blocked in 5% BSA and subsequently exposed to primary antibodies specific for NGAL, diluted (1 : 1000) in PBS. The rabbit polyclonal anti-NGAL antibody, generously provided by Dr Gould (University of Wisconsin, Madison, WI), was raised against recombinant NGAL protein (Stoesz et al, 1998). After incubation with the appropriate secondary antibody, the membranes were treated with ECL reagent (Amersham Biosciences, Piscataway, NJ, USA) and exposed to autoradiographic films.…”

“…Immunohistochemistry experiments were performed on 39 formalin-fixed tissue samples representing normal (n ¼ 8), pancreatitis (n ¼ 4), and pancreatic adenocarcinoma (n ¼ 27), using the rabbit anti-NGAL polyclonal antibody (Stoesz et al, 1998). The results are summarised in the Tables 1 -3.…”

NFAT3 transcription factor inhibits breast cancer cell motility by targeting the Lipocalin 2 gene

“…A potential function for LCN2 in the migratory capacity of colon cells (Playford et al, 2006) and tissue invasion by leukemia cells (Leng et al, 2008) has also been documented. The LCN2 gene is specifically downregulated in estrogen receptor a positive (ERA þ ) breast cancer patients (Stoesz et al, 1998) and has been reported as a predictor of breast cancer progression (Bauer et al, 2008;Provatopoulou et al, 2009). It has been clearly shown that expression of ERA is associated with more differentiated, less invasive tumors.…”

NGAL decreases E-cadherin-mediated cell–cell adhesion and increases cell motility and invasion through Rac1 in colon carcinoma cells

“…1,4 NGAL mRNA and protein have been found to be overexpressed in a broad spectrum of cancers, including breast, ovarian, pancreatic, colorectal, lung, urinary bladder, and hepatic tumors. [5][6][7][8][9][10] Moreover, NGAL levels are elevated in the urine of breast and bladder cancer patients. 5,8 Thus, it is hypothesized that NGAL may play a role in cancer pathophysiology.…”