NGAL knockdown by siRNA in human cholangiocarcinoma cells suppressed invasion by reducing NGAL/MMP-9 complex formation

Lipocalin 2 (LCN2) confers acquired resistance to almonertinib in NSCLC through LCN2-MMP-9 signaling pathway

Almonertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is highly selective for EGFR-activating mutations as well as the EGFR T790M mutation in patients with advanced non-small cell lung cancer (NSCLC). However, the development of resistance inevitably occurs and poses a major obstacle to the clinical efficacy of almonertinib. Therefore, a clear understanding of the mechanism is of great significance to overcome drug resistance to almonertinib in the future. In this study, NCI-H1975 cell lines resistant to almonertinib (NCI-H1975 AR) were developed by concentration-increasing induction and were employed for clarification of underlying mechanisms of acquired resistance. Through RNA-seq analysis, the HIF-1 and TGF-β signaling pathways were significantly enriched by gene set enrichment analysis. Lipocalin-2 (LCN2), as the core node in these two signaling pathways, were found to be positively correlated to almonertinib-resistance in NSCLC cells. The function of LCN2 in the drug resistance of almonertinib was investigated through knockdown and overexpression assays in vitro and in vivo. Moreover, matrix metalloproteinases-9 (MMP-9) was further identified as a critical downstream effector of LCN2 signaling, which is regulated via the LCN2-MMP-9 axis. Pharmacological inhibition of MMP-9 could overcome resistance to almonertinib, as evidenced in both in vitro and in vivo models. Our findings suggest that LCN2 was a crucial regulator for conferring almonertinib-resistance in NSCLC and demonstrate the potential utility of targeting the LCN2-MMP-9 axis for clinical treatment of almonertinib-resistant lung adenocarcinoma.

Lipocalin-2: A Nurturer of Tumor Progression and a Novel Candidate for Targeted Cancer Therapy

Within the tumor microenvironment (TME) exists a complex signaling network between cancer cells and stromal cells, which determines the fate of tumor progression. Hence, interfering with this signaling network forms the basis for cancer therapy. Yet, many types of cancer, in particular, solid tumors, are refractory to the currently used treatments, so there is an urgent need for novel molecular targets that could improve current anti-cancer therapeutic strategies. Lipocalin-2 (Lcn-2), a secreted siderophore-binding glycoprotein that regulates iron homeostasis, is highly upregulated in various cancer types. Due to its pleiotropic role in the crosstalk between cancer cells and stromal cells, favoring tumor progression, it could be considered as a novel biomarker for prognostic and therapeutic purposes. However, the exact signaling route by which Lcn-2 promotes tumorigenesis remains unknown, and Lcn-2-targeting moieties are largely uninvestigated. This review will (i) provide an overview on the role of Lcn-2 in orchestrating the TME at the level of iron homeostasis, macrophage polarization, extracellular matrix remodeling, and cell migration and survival, and (ii) discuss the potential of Lcn-2 as a promising novel drug target that should be pursued in future translational research.

Reciprocal interactions between innate immune cells and astrocytes facilitate neuroinflammation and brain metastasis via lipocalin-2

Brain metastasis still encompass very grim prognosis and therefore understanding the underlying mechanisms is an urgent need toward developing better therapeutic strategies. We uncover the intricate interactions between recruited innate immune cells and resident astrocytes in the brain metastatic niche that facilitate metastasis of melanoma and breast cancer. We show that granulocyte-derived lipocalin-2 (LCN2) induces inflammatory activation of astrocytes, leading to myeloid cell recruitment to the brain. LCN2 is central to inducing neuroinflammation as its genetic targeting or bone-marrow transplantation from LCN2^-/- mice was sufficient to attenuate neuroinflammation and inhibit brain metastasis. Moreover, high LCN2 levels in patient blood and brain metastases in multiple cancer types were strongly associated with disease progression and poor survival. Our findings uncover a previously unknown mechanism, establishing a central role for the reciprocal interactions between granulocytes and astrocytes in promoting brain metastasis and implicate LCN2 as a prognostic marker and potential therapeutic target.

Lipocalin-2 inhibits pancreatic cancer stemness via the AKT/c-Jun pathway

Cancer stem cells (CSCs) are involved in cancer recurrence and metastasis owing to their self-renewal properties and drug-resistance capacity. Lipocalin-2 (Lcn2) of the lipocalin superfamily is highly expressed in pancreatic cancer. Nevertheless, reports on the involvement of Lcn2 in the regulation of pancreatic CSC properties are scant. This study is purposed to investigate whether Lcn2 plays a crucial role in CSC renewal and stemness maintenance in pancreatic carcinoma. Immunohistochemistry results of tumor tissue chips together with Gene Expression Omnibus sequencing files confirmed that Lcn2 is highly expressed in pancreatic carcinoma compared with that in normal tissues. The exogenous expression of Lcn2 attenuated CSC-associated SOX2, CD44, and EpCAM expression and suppressed sarcosphere formation and tumorigenesis in the pancreatic carcinoma cell line PANC-1, which showed low expression of Lcn2. However, Lcn2 knockout in BxPC-3 cell line, which presented high Lcn2 expression, promoted CSC stemness, further enhancing sarcosphere formation and tumorigenesis. Moreover, Lcn2 was found to regulate stemness in pancreatic cancer depending on the activation of AKT and c-Jun. Lcn2 suppresses stemness properties in pancreatic carcinoma by activating the AKT-c-Jun pathway, and thus, it may be a novel candidate to suppress the stemness of pancreatic cancer. This study provides a new insight into disease progression.

Chronic Benzene Exposure Aggravates Pressure Overload-Induced Cardiac Dysfunction

Benzene is a ubiquitous environmental pollutant abundant in household products, petrochemicals and cigarette smoke. Benzene is a well-known carcinogen in humans and experimental animals; however, little is known about the cardiovascular toxicity of benzene. Recent population-based studies indicate that benzene exposure is associated with an increased risk for heart failure. Nonetheless, it is unclear whether benzene exposure is sufficient to induce and/or exacerbate heart failure. We examined the effects of benzene (50 ppm, 6 h/day, 5 days/week, 6 weeks) or HEPA-filtered air exposure on transverse aortic constriction (TAC)-induced pressure overload in male C57BL/6J mice. Our data show that benzene exposure had no effect on cardiac function in the Sham group; however, it significantly compromised cardiac function as depicted by a significant decrease in fractional shortening and ejection fraction, as compared with TAC/Air-exposed mice. RNA-seq analysis of the cardiac tissue from the TAC/benzene-exposed mice showed a significant increase in several genes associated with adhesion molecules, cell-cell adhesion, inflammation, and stress response. In particular, neutrophils were implicated in our unbiased analyses. Indeed, immunofluorescence studies showed that TAC/benzene exposure promotes infiltration of CD11b+/S100A8+/myeloperoxidase+-positive neutrophils in the hearts by 3-fold. In vitro, the benzene metabolites, hydroquinone and catechol, induced the expression of P-selectin in cardiac microvascular endothelial cells by 5-fold and increased the adhesion of neutrophils to these endothelial cells by 1.5-2.0-fold. Benzene metabolite-induced adhesion of neutrophils to the endothelial cells was attenuated by anti-P-selectin antibody. Together, these data suggest that benzene exacerbates heart failure by promoting endothelial activation and neutrophil recruitment.

TGF-β-induced PLEK2 promotes metastasis and chemoresistance in oesophageal squamous cell carcinoma by regulating LCN2

Oesophageal squamous cell carcinoma (ESCC) has a relatively unfavourable prognosis due to metastasis and chemoresistance. Our previous research established a comprehensive ESCC database (GSE53625). After analysing data from TCGA database and GSE53625, we found that PLEK2 predicted poor prognosis in ESCC. Moreover, PLEK2 expression was also related to the overall survival of ESCC patients undergoing chemotherapy. Repression of PLEK2 decreased the proliferation, migration, invasion and chemoresistance of ESCC cells in vitro and decreased tumorigenicity and distant metastasis in vivo. Mechanistically, luciferase reporter assay and chromatin immunoprecipitation assay suggested that TGF-β stimulated the process that Smad2/3 binds to the promoter sequences of PLEK2 and induced its expression. RNA-seq suggested LCN2 might a key molecular regulated by PLEK2. LCN2 overexpression in PLEK2 knockdown ESCC cells reversed the effects of decreased migration and invasion. In addition, TGF-β induced the expression of LCN2, but the effect disappeared when PLEK2 was knockdown. Moreover, AKT was phosphorylated in all regulatory processes. This study detected the major role of PLEK2 in driving metastasis and chemoresistance in ESCC by regulating LCN2, which indicates the potential use of PLEK2 as a biomarker to predict prognosis and as a therapeutic target for ESCC.

The Adipokine Component in the Molecular Regulation of Cancer Cell Survival, Proliferation and Metastasis

A hormonal imbalance may disrupt the rigorously monitored cellular microenvironment by hampering the natural homeostatic mechanisms. The most common example of such hormonal glitch could be seen in obesity where the uprise in adipokine levels is in virtue of the expanding bulk of adipose tissue. Such aberrant endocrine signaling disrupts the regulation of cellular fate, rendering the cells to live in a tumor supportive microenvironment. Previously, it was believed that the adipokines support cancer proliferation and metastasis with no direct involvement in neoplastic transformations and tumorigenesis. However, the recent studies have reported discrete mechanisms that establish the direct involvement of adipokine signaling in tumorigenesis. Moreover, the individual adipokine profile of the patients has never been considered in the prognosis and staging of the disease. Hence, the present manuscript has focused on the reported extensive mechanisms that culminate the basis of poor prognosis and diminished survival rate in obese cancer patients.

Lipocalin-2 Inhibits Osteosarcoma Cell Metastasis by Suppressing MET Expression via the MEK-ERK Pathway

Simple Summary

Higher neutrophil-derived cytokine lipocalin-2 (LCN2) expression possesses a versatile role in a myriad of cancers, but little is known about the role of LCN2 on osteosarcoma metastasis. In this study, we demonstrated that higher LCN2 inhibited cellular motility, migration, and invasion of osteosarcoma cells. Moreover, the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 was decreased by LCN2 knockdown. Conclusively, LCN2 inhibits osteosarcoma cell metastasis by suppressing MET via the mitogen-activated protein kinases/ERK kinase (MEK)–ERK pathway.

Abstract

Higher neutrophil-derived cytokine lipocalin-2 (LCN2) expression possesses a versatile role in a myriad of cancers, but little is known about the role of LCN2 on osteosarcoma metastasis. In this study, we demonstrated that higher LCN2 inhibited cellular motility, migration, and invasion of osteosarcoma cells. Moreover, using RNA sequencing technology, we found that LCN2 repressed MET gene expression in U2OS cells. Manipulation of LCN2 levels influenced the migratory potential of osteosarcoma cells as cellular migration was enhanced by transfecting with vectors containing a constitutively active LCN2 cDNA and recombinant human LCN2. Moreover, the phosphorylation of mitogen-activated protein kinases/extracellular signal-regulated kinase (ERK) kinase (MEK) 1/2 and ERK 1/2 was decreased by LCN2 knockdown. Furthermore, the use of ERK inhibitor (U0126) and activator (tBHQ) confirmed that the pharmaceutic inhibition of MEK–ERK augmented the LCN2-mediated MET suppression and migration of U2OS and HOS cells. Conclusively, LCN2 inhibits osteosarcoma cell metastasis by suppressing MET via the MEK–ERK pathway.

May Neutrophil Gelatinase-Associated Lipocalin (NGAL) Level Predict Mortality in Patients with Hepatocellular Carcinoma (HCC)?

PURPOSE

Hepatocellular carcinoma (HCC) ranks fifth among the common cancers worldwide. Hepatocarcinogenesis is a multiple-phases process, which involves changes in cellular genomes including high cell proliferation.In this study, we aimed to evaluate the relationship of NGAL level at the time of diagnosis with mortality in patients diagnosed with HCC.

MATERIAL AND METHODS

A total of 35 patients who developed HCC on the ground of HBV(+) and 30 healthy subjects were included in the study. Barcelona Clinic Liver Cancer (BCLC), Okuda staging system, and Milan criteria were used for staging of the patients with HCC.

RESULTS

The mean age of all patients was 59.54 ± 11.57 years. Seventeen (48.6%) HCC patients died during 1-year follow-up. Survival of the patients who met the Milan criteria was longer (log-rank (Mantel-Cox) test, χ2 = 5.353, p = 0.021). Kaplan-Meier curve was drawn for NGAL cut-off value, mortality was found to be higher in patients with a NGAL level higher than 217.50 (log-rank (Mantel-Cox) test, χ2 = 15.540, p < 0.001).

CONCLUSION

In this study, we found that high levels of NGAL at the time of diagnosis were associated with poor prognosis in HCC patients.

A Scoping Review on Lipocalin-2 and Its Role in Non-Alcoholic Steatohepatitis and Hepatocellular Carcinoma

Excess calorie intake and a sedentary lifestyle have made non-alcoholic fatty liver disease (NAFLD) one of the fastest growing forms of liver disease of the modern world. It is characterized by abnormal accumulation of fat in the liver and can range from simple steatosis and non-alcoholic steatohepatitis (NASH) to cirrhosis as well as development of hepatocellular carcinoma (HCC). Biopsy is the golden standard for the diagnosis and differentiation of all NAFLD stages, but its invasiveness poses a risk for patients, which is why new, non-invasive ways of diagnostics ought to be discovered. Lipocalin-2 (LCN2), which is a part of the lipocalin transport protein family, is a protein formally known for its role in iron transport and in inflammatory response. However, in recent years, its implication in the pathogenesis of NAFLD has become apparent. LCN2 shows significant upregulation in several benign and malignant liver diseases, making it a good candidate for the NAFLD biomarker or even a therapeutic target. What makes LCN2 more interesting to study is the fact that it is overexpressed in HCC development induced by chronic NASH, which is one of the primary causes of cancer-related deaths. However, to this day, neither its role as a biomarker for NAFLD nor the molecular mechanisms of its implication in NAFLD pathogenesis have been completely elucidated. This review aims to gather and closely dissect the current knowledge about, sometimes conflicting, evidence on LCN2 as a biomarker for NAFLD, its involvement in NAFLD, and NAFLD-HCC related pathogenesis, while comparing it to the findings in similar pathologies.

Biological Functions and Therapeutic Potential of Lipocalin 2 in Cancer

Lipocalin-2 (LCN2) is a secreted glycoprotein linked to several physiological roles, including transporting hydrophobic ligands across cell membranes, modulating immune responses, maintaining iron homeostasis, and promoting epithelial cell differentiation. Although LNC2 is expressed at low levels in most human tissues, it is abundant in aggressive subtypes of cancer, including breast, pancreas, thyroid, ovarian, colon, and bile duct cancers. High levels of LCN2 have been associated with increased cell proliferation, angiogenesis, cell invasion, and metastasis. Moreover, LCN2 modulates the degradation, allosteric events, and enzymatic activity of matrix metalloprotease-9, a metalloprotease that promotes tumor cell invasion and metastasis. Hence, LCN2 has emerged as a potential therapeutic target against many cancer types. This review summarizes the most relevant findings regarding the expression, biological roles, and regulation of LCN2, as well as the proteins LCN2 interacts with in cancer. We also discuss the approaches to targeting LCN2 for cancer treatment that are currently under investigation, including the use of interference RNAs, antibodies, and gene editing.

Revisiting Neutrophil Gelatinase-Associated Lipocalin (NGAL) in Cancer: Saint or Sinner?

Human neutrophil gelatinase-associated lipocalin (NGAL) is a glycoprotein present in a wide variety of tissues and cell types. NGAL exists as a 25 kDa monomer, a 46 kDa homodimer (the most abundant form in healthy subjects) and a 130 kDa disulfide-linked heterodimer bound to latent matrix metalloproteinase-9. Dysregulated expression of NGAL in human malignancies suggests its value as a clinical marker. A growing body of evidence is highlighting NGAL’s paradoxical (i.e., both beneficial and detrimental) effects on cellular processes associated with tumor development (proliferation, survival, migration, invasion, and multidrug resistance). At least two distinct cell surface receptors are identified for NGAL. This review (i) summarizes our current knowledge of NGAL’s expression profiles in solid tumors and leukemias, and (ii) critically evaluates the beneficial and detrimental activities of NGAL having been documented in a diverse range of cancer-derived cell lines. A better understanding of the causal relationships between NGAL dysregulation and tumor development will require a fine analysis of the molecular aspects and biological role(s) of NGAL both in primary tumors and at different stages of disease. Having an accurate picture of NGAL’s contribution to tumor progression is a prerequisite for attempting to modulate this protein as a putative therapeutic target.

Lipocalin-2 and iron trafficking in the tumor microenvironment

Iron is an essential element for virtually all organisms. It facilitates cell proliferation and growth but also contributes to major hallmarks of cancer such as tumor initiation, growth, and metastasis. Often, iron handling of tumor cells is disturbed, with altered iron acquisition, efflux, and storage. Targeting perturbed iron metabolic pathways might open opportunities towards novel approaches in cancer treatment. It is becoming clear that cells of the tumor microenvironment such as macrophages contribute to tumor progression. Since macrophages evolved a multitude of mechanisms to sequester, transport, store, and release iron it can be speculated that tumor cells educate them to supply iron to support tumor growth. Recent evidence supports the existence of transferrin-independent iron transport mechanisms in the tumor microenvironment, which points to local iron transport proteins such as lipocalin-2 and/or low molecular weight iron-trafficking substances such as siderophores. We hypothesize that tumor cells educate immune cells, i.e. macrophages in their neighborhood to make them delivering iron for the benefit of cancer progression. In particular, we pay attention to recent developments, pointing to lipocalin-2 and siderophores as alternative iron transport molecules in the tumor microenvironment.

MART-10 represses cholangiocarcinoma cell growth and high vitamin D receptor expression indicates better prognosis for cholangiocarcinoma

Cholangiocarcinoma (CCA) is a devastating disease due to no effective treatments available. Since the non-mineral functions of vitamin D emerges, 1α,25(OH)₂D₃, the active form of vitamin D, has been applied in anti-cancer researches. In this study, we demonstrated that both the 1α,25(OH)₂D₃ analog, MART-10, and 1α,25(OH)₂D₃ possessed anti-growth effect on human CCA cells with MART-10 much more potent than 1α,25(OH)₂D₃. The growth inhibition of both drugs were mediated by induction of G0/G1 cell cycle arrest through upregulation of p27 and downregulation of CDK4, CDK6, and cyclin D3. Human neutrophil gelatinase associated lipocalin (NGAL) was found to be involved in 1α,25(OH)₂D₃ and MART-10 meditated growth inhibition for CCA as knockdown of NGAL decreased Ki-67 expression in SNU308 cells and rendered SNU308 cells less responsive to 1α,25(OH)₂D₃ and MART-10 treatment. Vitamin D receptor (VDR) knockdown partly abolished MART-10-induced inhibition of NGAL and cell growth in SNU308 cells. The xenograft animal study demonstrated MART-10 could effectively repressed CCA growth in vivo without inducing obvious side effects. The IHC examination of human CCA specimen for VDR revealed that higher VDR expression was linked with better prognosis. Collectively, our results suggest that MART-10 could be a promising regimen for CCA treatment.

Lipocalin 2 (LCN2) is a promising target for cholangiocarcinoma treatment and bile LCN2 level is a potential cholangiocarcinoma diagnostic marker

Cholangiocarcinoma (CCA) is a devastating disease due to resistance to traditional chemotherapies and radiotherapies. New therapeutic strategies against CCA are urgently needed. This study investigated the role of lipocalin-2 (LCN2) in human cholangiocarcinoma as a potential therapeutic target and diagnostic marker. So far, the role of LCN2 in cancer is still controversial and studies regarding the role of LCN2 in CCA are limited. LCN2 knockdown inhibited CCA cell growth in vitro and in vivo through induction of cell cycle arrest at G0/G1 phases and decreased metastatic potential due to repression of epithelial-mesenchymal transition (EMT). Overexpression of LCN2 in CCA cells increased cell metastatic potential. We showed for the first time that the N-myc downstream regulated gene 1 (NDRG1) and NDRG2, known as tumor suppressor genes, are negatively regulated by LCN2 in CCA cells. LCN2 concentration in bile was higher in patients with CCA than that in patients with gallstones, with a cutoff value of 20.08 ng/ml making this a potential diagnostic marker. Higher LCN2 expression was associated with worse survival in patients with CCA. LCN2 is a promising target for CCA treatment and bile LCN2 level is a potential diagnostic marker for CCA.

Proteomic analysis of minute amount of colonic biopsies by enteroscopy sampling

Colorectal cancer (CRC) is one of the most common types of malignant tumor worldwide. Currently, although many researchers have been devoting themselves in CRC studies, the process of locating biomarkers for CRC early diagnosis and prognostic is still very slow. Using a centrifugal proteomic reactor-based proteomic analysis of minute amount of colonic biopsies by enteroscopy sampling, 2620 protein groups were quantified between cancer mucosa and adjacent normal colorectal mucosa. Of which, 403 protein groups were differentially expressed with statistic significance between cancer and normal tissues, including 195 up-regulated and 208 down-regulated proteins in cancer tissues. Three proteins (SOD3, PRELP and NGAL) were selected for further Western blot validation. And the resulting Western blot experimental results were consistent with the quantitative proteomic data. SOD3 and PRELP are down-regulated in CRC mucosa comparing to adjacent normal tissue, while NGAL is up-regulated in CRC mucosa. In conclusion, the centrifugal proteomic reactor-based label-free quantitative proteomic approach provides a highly sensitive and powerful tool for analyzing minute protein sample from tiny colorectal biopsies, which may facilitate CRC biomarkers discovery for diagnoses and prognoses.

Transcription factor 7-like 1 dysregulates keratinocyte differentiation through upregulating lipocalin 2

Recent studies strongly suggested that transcription factor 7-like 1 (Tcf7l1, also known as Tcf3) is involved in the differentiation of several types of cells, and demonstrated that Tcf7l1 modulates keratinocytes physiologically through regulating lipocalin 2 (LCN2), a key regulator of cell differentiation. To reveal the potential role of Tcf7l1 in the dysregulation of keratinocyte differentiation, both Tcf7l1 and LCN2 were determined in a variety of skin disorders. The in vitro effect of Tcf7l1 on keratinocyte differentiation was studied by culturing SCC-13 cells, and the human foreskin keratinocytes (HFKs) that were transfected with vectors for overexpressing human papillomavirus E6/E7 or Tcf7l1 genes. We found that both Tcf7l1 and LCN2 were highly expressed in those diseases characterized by defective keratinocyte differentiation (especially psoriasis vulgaris, condyloma acuminatum, squamous cell carcinoma, etc). Moreover, compared with control HFKs, SCC-13 cells and E6/E7-harboring HFKs expressed more Tcf7l1 and LCN2. Tcf7l1 siRNA transfection decreased LCN2 but increased involucrin and loricrin in HFKs under calcium stimuli. Conversely, Tcf7l1 overexpression in SCC-13 cells or vector-transfected HFKs induced lower involucrin and loricrin expression and less keratinocyte apoptosis, both of which, however, were partially abrogated by LCN2 siRNA or neutralizing anti-LCN2 antibody. Interestingly, the Tcf7l1 expression in HFKs correlated positively with the MMP-2 level, and the inhibition of MMP-2 decreased the LCN2 level and even attenuated the effect of Tcf7l1 on LCN2 expression. Therefore, Tcf7l1 dysregulates keratinocyte differentiation, possibly through upregulating the LCN2 pathway in an MMP-2 mediated manner. Elucidating the interaction between Tcf7l1 and LCN2 may help understand disordered cell differentiation in some skin diseases.

Elevated Expression of Matrix Metalloproteinase-9 not Matrix Metalloproteinase-2 Contributes to Progression of Extracranial Arteriovenous Malformation

Extracranial arteriovenous malformations (AVMs) are rare but dangerous congenital lesions arising from direct arterial-venous shunts without intervening capillaries. Progressive infiltration, expansion, and soft tissue destruction lead to bleeding, pain, debilitation and disfigurement. The pathophysiology of AVMs is not well understood. Matrix Metalloproteinases (MMPs) are thought to play an important role in pathologic processes underlying many diseases. This study investigates the expression of MMP-9 and MMP-2 in aggressive extracranial AVMs. The differential expression of MMP-9 and its regulatory factors is also examined. Herein we demonstrate that mRNA and protein expressions of MMP-9, but not MMP-2, are significantly higher in AVM tissues compared to normal tissues. The serum level of MMP-9, but not MMP-2, is also elevated in AVM patients compared to healthy controls. MMP-9/neutrophil gelatinase-associated lipocalin (NGAL) complex is also significantly increased in AVM tissues. The MMP-9/ tissue inhibitor of metalloproteases-1 (TIMP-1) complex presents as a major form detected in normal tissues. The increased and aberrant expression of MMP-9 and specific MMP-9 forms may help explain the constitutive vascular remodeling and infiltrative nature of these lesions. Specific MMP-9 inhibitors would be a promising treatment for AVMs.

HGF mediated upregulation of lipocalin 2 regulates MMP9 through nuclear factor-κB activation

Lipocalin 2 (LCN2) is a member of lipocalin family that binds and transports a small lipophilic ligand, sharing a highly conserved tertiary structure and can be found as a monomer, homodimer, heterodimer with matrix metalloproteinase 9 (MMP9). The high molecule LCN2/MMP9 complex was found in several cancer types. Yet, the mechanisms of regulation between LCN2 with MMP9 in tumorigenesis is unclear. The aims of the present study were to identify the function of LCN2 associated with MMP9 in gastric cancer growth and metastasis. First, we confirmed that the expression level of LCN2 and MMP9 was upregulated by hepatocyte growth factor (HGF). To identify the association pathway of HGF-induced LCN2, the cells were treated with PI3-kinase inhibitor (LY294002), or MEK inhibitor (PD098059), or p38 inhibitor (SB203580) and then analyzed using western blotting. The HGF-mediated LCN2 protein level was decreased with LY294002. Also, the HGF-mediated MMP9 was decreased with LY294002. The role for LCN2 with HGF mediated MMP9 was determined by knockdown of LCN2. LCN2-sh RNA cells showed a decreased level of HGF-mediated MMP9. The HGF-mediated LCN2 protein level was decreased with treatment of the NFκB inhibitor. We confirmed the role of HGF-mediated LCN2. HGF-mediated cell proliferation and in vitro invasion was decreased in LCN2 knockdown cell. In conclusion, the present study showed that LCN2 upregulated MMP9 through PI3K/AKT/NFκB pathway in gastric cancer. LCN2 has a role in cell proliferation and cell invasion in gastric cancer, which may be a possible target for developing gastric cancer therapy.

Chemopreventive and chemotherapeutic effect of dietary supplementation of vitamin D on cholangiocarcinoma in a Chemical-Induced animal model

Intrahepatic cholangiocarcinoma (ICC) is an aggressive cancer. Vitamin D supplementation is getting popular due to its anti-tumor functions after conversion to its active form, 1α,25(OH)₂D. Here, we show that dietary supplementation with 6 IU/g of vitamin D greatly suppressed ICC initiation and progression without apparent toxicity in a chemically induced rat model. Microarray analysis of rat ICC tissues showed vitamin D supplementation modulated the expressions of several unique genes, including lipocalin 2 (Lcn2), confirmed by RT-qPCR and immunohistochemical (IHC) staining. Further, 53 of 80 human ICC specimens (66%) exhibited high LCN2 expression and LCN2 knockdown in SNU308 cells decreased cell growth and migration, suggesting LCN2 be an oncogene in human ICC. As human ICC SNU1079 cells were treated by 1α,25(OH)₂D₃, LCN2 expression and cell proliferation were attenuated. The downregulation of LCN2 expression was blunted when vitamin D receptor (VDR) was knocked down, implicating that the in vivo Lcn2 downregulation is a direct consequence of vitamin D supplementation

Our results support the prevailing concept that vitamin D status is negatively associated with cancer incidence and mortality and suggest LCN2 may be a potential target against ICC. Further studies of application of vitamin D or its analogs against ICC are warranted.

Biomarkers in bile-complementing advanced endoscopic imaging in the diagnosis of indeterminate biliary strictures

Biliary strictures present a diagnostic challenge and a conundrum, particularly when an initial work up including abdominal imaging and endoscopic retrograde cholangiopancreatography based sampling are non-diagnostic. Advances in endoscopic imaging have helped us diagnose these strictures better. However, even with modern technology, some strictures remain a diagnostic challenge. The proximity of bile fluid to the bile duct epithelia makes it an attractive option to investigate for bio-markers, which might be representative of the functions/abnormal changes taking place in the biliary system. A number of biomarkers in bile have been discovered recently in approaching biliary strictures with their potential future diagnostic utility, further supported by the immunohistochemical analysis of the resected tissue specimens. Novel biliary biomarkers especially carcinoembryonic cell adhesion molecule 6 and neutrophil gelatinase-associated lipocalin seem promising in differentiating malignant from benign biliary strictures. Recent developments in lipidomic profiling of bile are also very promising. Biliary biomarkers appear to complement endoscopic imaging in diagnosing malignant etiologies of biliary stricture. Future studies addressing these biomarkers need to be incorporated to the current endoscopic techniques to determine the best approach in determining the etiology of biliary strictures.

Matrix Metalloproteinase-9/Neutrophil Gelatinase-Associated Lipocalin Complex Activity in Human Glioma Samples Predicts Tumor Presence and Clinical Prognosis

Matrix metalloproteinase-9/neutrophil gelatinase-associated lipocalin (MMP-9/NGAL) complex activity is elevated in brain tumors and may serve as a molecular marker for brain tumors. However, the relationship between MMP-9/NGAL activity in brain tumors and patient prognosis and treatment response remains unclear. Here, we compared the clinical characteristics of glioma patients with the MMP-9/NGAL activity measured in their respective tumor and urine samples. Using gelatin zymography assays, we found that MMP-9/NGAL activity was significantly increased in tumor tissues (TT) and preoperative urine samples (Preop-1d urine). Activity was reduced by seven days after surgery (Postop-1w urine) and elevated again in cases of tumor recurrence. The MMP-9/NGAL status correlated well with MRI-based tumor assessments. These findings suggest that MMP-9/NGAL activity could be a novel marker to detect gliomas and predict the clinical outcome of patients.

Neutrophil gelatinase-associated lipocalin in cancer

Neutrophil gelatinase-associated lipocalin (NGAL), also known as lipocalin-2, is a 178-amino acid protein which exists in three molecular forms, including a 25-kDa monomer, a 45-kDa homodimer, and a 135-kDa heterodimer complexed with matrix metalloproteinase 9 (MMP-9). Polymorphonuclear neutrophils and tubular cells of the kidney are the most representative cellular sources. As such, NGAL is now considered the biochemical gold standard for early diagnosis of acute kidney injury. Recent evidence suggests, however, that ectopic or enhanced expression of NGAL may occur in many other pathologic conditions including cancer. Several epidemiologic studies, as reviewed in this chapter, showed that a variety of malignant tumors consistently overexpressed NGAL with increased concentration in blood, urine, and other biologic fluids. In addition, NGAL was frequently associated with tumor size, stage, and invasiveness. These features thus make it a potential biomarker for malignancy. A number of experimental studies also demonstrated that the ability to bind MMP-9, to scavenge iron into cancer cells along with the effect on subcellular localization of transmembrane proteins such as cadherins and catenins, confers this protein the potential to enhance can cer aggressiveness and makes it an appealing target of future anticancer research.

Neutrophil Gelatinase-Associated Lipocalin (NGAL), Pro-Matrix Metalloproteinase-9 (pro-MMP-9) and Their Complex Pro-MMP-9/NGAL in Leukaemias

Matrix metalloproteinase (MMP)-9 and neutrophil gelatinase-associated lipocalin (NGAL) have gained attention as cancer biomarkers. The inactive zymogen form of MMP-9 (pro-MMP-9) also exists as a disulphide-linked heterodimer bound to NGAL in humans. Leukaemias represent a heterogeneous group of neoplasms, which vary in their clinical behavior and pathophysiology. In this review, we summarize the current literature on the expression profiles of pro-MMP-9 and NGAL as prognostic factors in leukaemias. We also report the expression of the pro-MMP-9/NGAL complex in these diseases. We discuss the roles of (pro)-MMP-9 (active and latent forms) and NGAL in tumour development, and evaluate the mechanisms by which pro-MMP-9/NGAL may influence the actions of (pro)-MMP-9 and NGAL in cancer. Emerging knowledge about the coexpression and the biology of (pro)-MMP-9, NGAL and their complex in cancer including leukaemia may improve treatment outcomes.

Mycoepoxydiene induces apoptosis and inhibits TPA-induced invasion in human cholangiocarcinoma cells via blocking NF-κB pathway

Human cholangiocarcinoma (CCA) is a chemoresistant bile duct carcinoma with a poor prognosis. Conventional chemotherapy and radiotherapy have not been reported to be effective in improving long-term survival. Mycoepoxydiene (MED), a polyketide isolated from the marine fungal strain Diaporthe sp. HLY-1 associated with mangroves, has been shown to be an agent capable of inducing apoptosis in MCF-7 and Hela cell lines. However, little is known about the effect of MED in CCA. Herein, we investigated the effect of MED on CCA cells proliferation and invasion. The results demonstrated that MED induced apoptosis in CCA cells such as SK-ChA-1 and Mz-ChA-1 through inhibiting the expression of anti-apoptotic proteins such as Bcl-XL and Bcl-2, two targets of NF-κB. In addition, MED significantly inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced CCA cells invasion in a dose-dependent manner by reducing the expression of matrix metalloelastase 9 (MMP-9). Moreover, MED inhibited TPA-induced NF-κB activation via blocking phosphorylation and degradation of IκBα and phosphorylation of IκB kinase (IKK). MED had no effect on the activation of extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK) and p38, which are also involved in regulating the MMP-9 expression. Collectively, MED significantly suppressed proliferation and invasion of CCA cells such as SK-ChA-1 and Mz-ChA-1, suggesting that MED is a potential lead compound for the development of novel drugs for therapy of CCA.

Serum and bile NGAL for clinically distinguishing malignant biliary strictures from benign biliary strictures

AIM: To investigate the value of serum and bile neutrophil gelatinase associated lipocalin (NGAL) for distinguishing malignant strictures caused by cholangiocarcinoma (CCA) or pancreatic cancer from benign biliary strictures.

METHODS: The study was performed prospectively on patients admitted for endoscopic retrograde cholangiopancreatography biliary decompression. Forty-four patients with dilated biliary ducts, including 12 cases of CCA, 8 cases of pancreatic cancer, 1 case of carcinoma of the ampulla, and 23 cases of benign biliary strictures, were enrolled. Their sera and bile were collected to measure NGAL. Routine biochemistry including liver function test and routine blood examination was also performed. Enzyme-linked immunosorbent assay was performed to measure the contents of NGAL in serum and bile samples.

RESULTS: Serum NGAL had no significant value for discriminating malignant and benign biliary strictures (mean, 31.10 ng/mL vs 118.35 ng/mL, P = 0.0825). Biliary NGAL levels were significantly raised in the malignant disease group compared with the benign disease group (mean, 199.0 ng/mL vs 466.7 ng/mL, P = 0.0215).

CONCLUSION: Measurement of biliary NGAL, not serum NGAL, may differentiate malignant biliary strictures from benign biliary strictures.

WTAP regulates migration and invasion of cholangiocarcinoma cells

BACKGROUND

Wilms' tumor 1-associating protein (WTAP) is a nuclear protein that has been associated with the regulation of proliferation and apoptosis. Although its dynamic expression and physiological functions in vascular cells have been reported, its expression and roles in cholangiocarcinoma cells are poorly characterized.

METHODS

To examine the expression of WTAP in patient tissues, we performed immunohistochemistry. To examine motility of cholangiocarcinoma cells, we employed Boyden chamber, wound healing and Matrigel invasion assays, and a liver xenograft model.

RESULTS

Immunohistochemistry in patient tissues showed WTAP overexpression in cholangiocarcinoma tissues and correlation of WTAP expression with metastasis of cholangiocarcinoma cells. Overexpression or knockdown of WTAP significantly increased or decreased the motility of cholangiocarcinoma cells. Moreover, WTAP overexpression or knockdown significantly increased or decreased tumorigenicity of cholangiocarcinoma cells in an orthotopic xenograft model. Furthermore, microarray study showed that WTAP induce the expressions of MMP7, MMP28, cathepsin H and Muc1.

CONCLUSION

WTAP is overexpressed in cholangiocarcinoma and regulates motility of cholangiocarcinoma cells.

Lipocalin-2 elicited by advanced glycation end-products promotes the migration of vascular smooth muscle cells

Advanced glycation end-products (AGEs) play key roles in the development of diabetic vascular complications by activating the proliferation and migration of vascular smooth muscle cells. Here, we identified an increase of the migratory properties of human aortic smooth muscle cells (HASMC) through AGE-induced expression of lipocalin-2 (LCN2). Because the AGE-elicited expression of LCN2 was diminished by an antibody against the AGE receptor (RAGE), diphenylene iodonium (DPI), N-acetyl cysteine, LY294002, and SP600125, we suggest that AGEs enhance the expression of LCN2 via a RAGE-NADPH oxidase-reactive oxygen species pathway, leading to the phosphorylation of PI3K-Akt and JNK in HASMCs. In addition, a chromatin immunoprecipitation assay and promoter assay revealed that CCAAT/enhancer binding protein β is crucial for AGE-induced expression of LCN2. However, any other AGE-related signaling pathway, including ERK1/2, p38, NF-κB, and AP-1, did not affect the AGE- induced expression of LCN2. Knockdown of LCN2 expression by shRNA showed that AGE-elicited LCN2 expression enhanced the invasive and migratory properties of HASMCs, but showed no effect on cell proliferation. Considering the importance of HASMC migration in the development of atherosclerosis, our study provides a novel insight into diabetic vascular complications.

Expression and complex formation of MMP9, MMP2, NGAL, and TIMP1 in porcine myocardium but not in skeletal muscles in male pigs with tachycardia-induced systolic heart failure

Matrix metalloproteinases (MMPs) are involved in the remodeling of extracellular matrix in various tissues. Their functioning could be related to the formation of complexes, containing MMP9, MMP2, tissue inhibitor of metalloproteinases type 1 (TIMP1), and neutrophil gelatinase-associated lipocalin (NGAL). Such complexes have not been investigated in either myocardial or skeletal muscles. We examined 20 male pigs with heart failure (HF), and 5 sham-operated animals. There were no differences in the mRNA expression of MMP9, MMP2, TIMP1, and NGAL between diseased and healthy animals, in either left ventricle (LV) myocardium or skeletal muscles. In LV from both diseased and healthy animals, in nonreducing and nondenaturing conditions, we demonstrated the presence of high molecular weight (HMW) complexes (130, 170, and 220 kDa) containing MMP9, TIMP1, and NGAL (also MMP2 in 220 kDa complex) without proteolytic activity, and a proteolytically active 115 kDa MMP9 form together with 72 and 68 kDa bands (proMMP2 and MMP2). Proteolytically active bands were also spontaneously released from HMW complexes. In skeletal muscles from both diseased and healthy animals, in nonreducing and nondenaturing conditions, we found no HMW complexes, and proteolytic activity was associated with the presence of 72 and 68 kDa bands (proMMP2 and MMP2).

The challenge of cholangiocarcinoma: dissecting the molecular mechanisms of an insidious cancer

Cholangiocarcinoma is a fatal cancer of the biliary epithelium and has an incidence that is increasing worldwide. Survival beyond a year of diagnosis is less than 5%, and therapeutic options are few. Known risk factors include biliary diseases such as primary sclerosing cholangitis and parasitic infestation of the biliary tree, but most cases are not associated with any of these underlying diseases. Numerous in vitro and in vivo models, as well as novel analytical techniques for human samples, are helping to delineate the many pathways implicated in this disease, albeit at a frustratingly slow pace. As yet, however, none of these studies has been translated into improved patient outcome and, overall, the pathophysiology of cholangiocarcinoma is still poorly understood. There remains an urgent need for new approaches and models to improve management of this insidious and devastating disease. In this review, we take a bedside-to-bench approach to discussing cholangiocarcinoma and outline research opportunities for the future in this field.

Lipocalin 2, a new GADD153 target gene, as an apoptosis inducer of endoplasmic reticulum stress in lung cancer cells

Endoplasmic reticulum (ER) stress is activated under severe cellular conditions. GADD153, a member of the C/EBP family, is an unfolded protein response (UPR) responsive transcription factor. Increased levels of lipocalin 2, an acute phase protein, have been found in several epithelial cancers. The aim of this study is to investigate the function of lipocalin 2 in lung cancer cells under ER stress. Treatment with thapsigargin, an ER stress activator, led to increases in cytotoxicity, ER stress, apoptosis, and lipocalin 2 expression in A549 cells. GADD153 silencing decreased lipocalin 2 expression in A549 cells. On chromatin immunoprecipitation assay, ER stress increased GADD153 DNA binding to lipocalin 2 promoter. Furthermore, silencing of lipocalin 2 mitigated ER stress-mediated apoptosis in A549 cells. Our findings demonstrated that lipocalin 2 is a new GADD153 target gene that mediates ER stress-induced apoptosis.

NGAL and NGALR overexpression in human hepatocellular carcinoma toward a molecular prognostic classification

AIM

Neutrophil gelatinase-associated lipocalin (NGAL) and its cell surface receptor, NGALR, have been implicated in tumorigenesis and tumor progression of various human malignant neoplasms. In particularly, it has been demonstrated that NGAL is overexpressed in hepatocellular carcinoma (HCC) tissues and closely associated with the proliferation and invasion of HCC cells. The aim of this study was to investigate the clinical significance of NGAL and NGALR in HCC.

METHODS

Expression of NGAL and NGALR was evaluated by immunohistochemistry in tumor tissues from 138 patients who underwent curative resection of HCC. The association of NGAL or NGALR expression with the clinicopathologic features was analyzed. Univariate and multivariate analyses were performed to evaluate the prognostic value of NGAL and/or NGALR expression for HCC patients.

RESULTS

The expression levels of NGAL and NGALR were both up-regulated in HCC tissues, and to be associated with vascular invasion (both P=0.03), TNM stage (both P=0.004), and tumor recurrence (both P<0.001). A positive correlation between expression of the two markers was also observed (r=0.89; P<0.001). Additionally, survival analysis showed that high expression of NGAL or NGALR was significantly associated with poor prognosis for patients with HCC (both P=0.003). Patients with high expression of both NGAL and NGALR had a shorter overall survival (P<0.001) than those with low expression of both. Furthermore, multivariate analysis showed both NGAL and NGALR were independent predictors of overall survival.

CONCLUSION

Our data demonstrate for the first time that the up-regulations of NGAL and NGALR expression in HCC were both significantly correlated with unfavorable clinicopathologic features and independent poor prognostic factor for overall survival in patients. These findings suggest that NGAL and NGALR expression might be served as novel prognostic factors and potential therapeutic targets in HCC.

Lipocalin 2 performs contrasting, location-dependent roles in APCmin tumor initiation and progression

Evidence that lipocalin 2 (LCN2) is oncogenic has grown in recent years and comes from both animal models and expression analysis from a variety of human cancers. In the intestine, LCN2 is overexpressed in colitis patients and its overexpression is a negative prognostic indicator in colorectal cancer. Functionally, LCN2 has a number of different activities that may contribute to its oncogenic potential, including increasing matrix metalloproteinase activity, control of iron availability and stimulating inflammation. In this report, we examined APCmin intestinal tumorigenesis in an LCN2-deficient background. We found that the loss of LCN2 increased tumor multiplicity specifically in the duodenum, suggesting a potential tumor-suppressive activity. Concurrently, however, LCN2 increased the average small intestinal tumor size particularly in the distal small intestine. We found that this increase was correlated to tumor iron(II) content, suggesting that an iron-scavenging role is important for LCN2 oncogenic activity in the intestine.

Role of lipocalin 2 and its complex with matrix metalloproteinase-9 in oral cancer

OBJECTIVES

Recent evidence demonstrated that lipocalin (LCN)2 is induced in many types of human cancer, while the detection of its complex with matrix metalloproteinase (MMP)-9 is correlated with the cancer disease status. We attempted to evaluate plasma expressions of LCN2, MMP-9, and their complex (LCN2/MMP-9) during the diagnostic work-up of patients with oral squamous cell carcinoma (OSCC) and investigated their correlations with disease progression.

METHODS

In total, 195 patients with OSCC and 81 healthy controls were recruited. Expression levels of LCN2, MMP-9, and LCN2/MMP-9 were determined with immunoenzymatic assays.

RESULTS

Patients with OSCC exhibited significantly higher levels of LCN2, MMP-9, and LCN2/MMP-9 compared with healthy controls (LCN2: P < 0.001; MMP-9: P < 0.001; LCN2/MMP-9: P < 0.01). Plasma levels of LCN2, MMP-9, and LCN2/MMP-9 in patients with OSCC were significantly correlated with each other and were associated with more-advanced clinical stages (P < 0.05) and/or a larger tumor size (P < 0.05), but were not associated with positive lymph-node metastasis or distal metastasis.

CONCLUSION

Our results suggest that plasma levels of LCN2 and the LCN2/MMP-9 complex may be useful in non-invasively monitoring OSCC progression, while supporting their potential role as biomarkers of oral cancer disease status.

Neutrophil gelatinase-associated lipocalin (NGAL) expression is dependent on the tumor-associated sigma-2 receptor S2RPgrmc1

Tumor invasion is a critical step in the spread of cancer. S2R (sigma-2 receptor)/Pgrmc1 (progesterone receptor membrane component 1) is a cytochrome b(5)-related drug-binding orphan receptor essential for tumor formation and invasion. Secretory proteins drive these processes, so we screened for S2R(Pgrmc1)-dependent secreted proteins using antibody arrays. S2R(Pgrmc1) markedly regulated the expression of NGAL/LCN2 (neutrophil gelatinase-associated lipocalin/lipocalin 2), a secreted glycoprotein that binds to MMP-9 (matrix metalloproteinase 9) and protects it from degradation. S2R(Pgrmc1) knock-down blocked NGAL/LCN2 expression at the protein and RNA levels and decreased MMP9 activity. NGAL expression was required for MMP-9 activity and tumor formation. S2R(Pgrmc1) associates with EGFR and increases EGFR levels at the plasma membrane, and the EGFR inhibitors erlotinib and AG1478, as well as Akt and ERK inhibitors, suppressed the NGAL/LCN2 RNA and protein levels. NGAL is transcriptionally regulated by NFκB, and S2R(Pgrmc1) knock-down decreased the NFκB subunit p65/RelA acetylation, phosphorylation, and activation. In S2R(Pgrmc1) knock-down cells, p65 acetylation was reversed by inhibitors of histone deacetylase 1, and the inhibitors partially restored NGAL levels. Our results are consistent with a model in which S2R(Pgrmc1) increases NGAL/LCN2 levels by activating NFκB via EGFR.

Lipocalin 2 in cancer: when good immunity goes bad

The innate immune molecule Lipocalin 2 (LCN2) was initially shown to combat bacterial infection by binding bacterial siderophores, hence impairing microbial iron sequestration. In recent years, it has become apparent that LCN2 is over-expressed in cancers of diverse histological origin and that it facilitates tumorigenesis by promoting survival, growth, and metastasis. Herein, we discuss emerging evidence that substantiates two functional roles for LCN2 in cancer: promotion of the epithelial-to-mesenchymal transition (EMT) that facilitates an invasive phenotype and metastasis, and sequestration of iron that results in cell survival and tumorigenesis. Further, we present evidence that upregulated LCN2 expression in solid tumors is induced by hypoxia and pro-inflammation, microenvironmental noxae that converge to cause an endoplasmic reticulum (ER) stress response. Taken together, it appears that tumor cells exploit the beneficial innate immune function of LCN2 to support uncontrolled growth. This duplicity in function highlights LCN2 and its upstream driver, the ER stress response, as key targets for cancer therapy.

Elevated levels of neutrophil gelatinase-associated lipocalin in bile from patients with malignant pancreatobiliary disease

OBJECTIVES

Accurate differentiation between benign and malignant causes of biliary obstruction remains challenging and reliable biomarkers are urgently needed. Bile is a potential source of such biomarkers. Our aim was to apply a proteomic approach to identify a potential biomarker in bile that differentiates between malignant and benign disease, and to assess its diagnostic accuracy. Neutrophil gelatinase-associated lipocalin (NGAL) is multi-functional protein, released from activated neutrophils, with roles in inflammation, immune function, and carcinogenesis. It has not previously been described in bile.

METHODS

Bile, urine, and serum were collected prospectively from 38 patients undergoing endoscopic retrograde cholangiopancreatography ("discovery" cohort); 22 had benign and 16 had malignant pancreatobiliary disease. Initially, label-free proteomics and immunoblotting were performed in samples from a subset of these patients. Enzyme-linked immunosorbent assay was then performed for NGAL as a potential biomarker on all samples in this cohort. The diagnostic performance of biliary NGAL was then validated in a second, independent group ("validation" cohort) of 21 patients with pancreatobiliary disease (benign n=14, malignant n=7).

RESULTS

NGAL levels were significantly raised in bile from the malignant disease group, compared with bile from the benign disease group in the discovery cohort (median 1,556 vs. 480 ng/ml, P=0.007). Biliary NGAL levels had a receiver operating characteristic area under curve of 0.76, sensitivity 94%, specificity 55%, positive predictive value 60%, and negative predictive value 92% for distinguishing malignant from benign causes. Biliary NGAL was independent of serum biochemistry and carbohydrate antigen 19-9 (CA 19-9) in differentiating between underlying benign and malignant disease. No significant differences in serum and urine NGAL levels were found between benign and malignant disease. Combining biliary NGAL and serum CA 19-9 improved diagnostic accuracy for malignancy (sensitivity 85%, specificity 82%, positive predictive value 79%, and negative predictive value 87%). The diagnostic accuracy of biliary NGAL was confirmed in the second independent validation cohort.

CONCLUSIONS

NGAL in bile is a novel potential biomarker to help distinguish benign from malignant biliary obstruction.

NGAL expression is elevated in both colorectal adenoma-carcinoma sequence and cancer progression and enhances tumorigenesis in xenograft mouse models

PURPOSE

There is growing evidence implicating that neutrophil gelatinase-associated lipocalin (NGAL) plays a role in the development and progression of cancers. However, the effect of NGAL in colorectal carcinoma (CRC) has not been clearly elucidated. In this study, we investigated the role of NGAL in the tumorigenesis and progression of CRC and evaluated the clinical value of NGAL expression.

EXPERIMENTAL DESIGN

We examined NGAL expression in 526 colorectal tissue samples, including 53 sets of matched specimens (histologically normal mucosa, adenomas, and carcinomas) using immunohistochemical analysis. In CRCs, correlations between NGAL expression and clinicopathologic parameters were analyzed, and survival analysis was conducted. The role of NGAL was further tested using mouse xenograft models.

RESULTS

NGAL expression was elevated during the colorectal adenoma-carcinoma sequence both among the 526 cases (r(s) = 0.66, P < 0.001) and in the 53 sets of matched specimens (r(s) = 0.60, P < 0.001). In CRCs, NGAL expression was associated with cancer stage (P = 0.041) and tumor recurrence in stage II patients (P = 0.037). Survival analysis revealed that NGAL expression was an independent prognostic factor for overall survival (HR = 1.84, P = 0.004) and for disease-free survival of stage II patients (HR = 5.88, P = 0.021). In mouse models, the xenografts in cecum and spleen were heavier and more numerous in the group injected with NGAL-overexpressing CRC cells (P < 0.05).

CONCLUSIONS

NGAL overexpression may promote the tumorigenesis and progression of CRC. Detecting NGAL expression in tumor tissues may be useful for evaluating prognosis of patients with CRC.

Neutrophil gelatinase-associated lipocalin in gastric carcinoma cells and its induction by TPA are controlled by C/EBPβ

Neutrophil gelatinase-associated lipocalin (NGAL) expression has been found to be upregulated in a variety of tumors, but the mechanism of NGAL elevation in gastric carcinoma remains unknown. Here, immunohistochemistry was applied to analyze NGAL expression in gastric carcinoma patients. Reverse transcription PCR, Western blot, and enzyme-linked immunosorbent assay (ELISA) were performed to evaluate NGAL mRNA and protein levels before and after 12-O-tetradecanoylphorbol-13-acetate (TPA) induction. Luciferase reporter assay was carried out to identify the core cis element in NGAL promoter. The binding ability and specificity of transcription factors were analyzed by electrophoretic mobility-shift assay (EMSA) and chromatin immunoprecipitation (ChIP), respectively. Results showed that NGAL was overexpressed in gastric tumor tissues. Gastric cancer cells treated with TPA resulted in the transactivation of NGAL promoter and the upregulation of its mRNA and protein levels. We identified the -110 to -79 sequence segment upstream from the transcription initiation site of NGAL as a TPA responsive element (TRE) and confirmed that C/EBPβ was able to bind to the -87 to -79 segment. Forced expression of C/EBPβ significantly increased the promoter activity of NGAL as well as its mRNA level. These results suggest that NGAL is overexpressed in gastric cancer, the binding of C/EBPβ to the TRE of its gene promoter mediates its TPA-induced overexpression in gastric carcinoma cells.

Serum NGAL to Clinically Distinguish Cholangiocarcinoma from Benign Biliary Tract Diseases

Aim. To determine whether the serum level of NGAL can discriminate cholangiocarcinoma from benign biliary tract disease in patients. Methods. This study was performed according to a prospective-specimen-collection, retrospective-blinded-evaluation (PRoBE) design. A total of 50 cholangiocarcinoma and 50 benign biliary tract disease cases were randomly selected from a cohort of consecutive cases of biliary tract diseases. Their sera were measured for the levels of NGAL and the widely used serum cholangiocarcinoma marker, carbohydrate antigen 19-9 (CA19-9). Results. The serum CA19-9 and NGAL levels were significantly elevated in cholangiocarcinoma patients (CA19-9: P < .001, NGAL: P < .001). The area under the curve (AUC) of a receiver operating characteristic (ROC) curve analysis for the diagnosis of cholangiocarcinoma of CA19-9 and NGAL was 0.81 and 0.79, respectively. Conclusion. The diagnostic accuracy of serum NGAL and CA19-9 makes them good candidates for use as biomarkers to discriminate cholangiocarcinoma patients from benign biliary tract disease patients.