Elevated plasma visfatin levels correlate with poor prognosis of gastric cancer patients

Extracellular nicotinamide phosphoribosyltransferase: role in disease pathophysiology and as a biomarker

Nicotinamide phosphoribosyltransferase (NAMPT) plays a central role in mammalian cell metabolism by contributing to nicotinamide adenine dinucleotide biosynthesis. However, NAMPT activity is not limited to the intracellular compartment, as once secreted, the protein accomplishes diverse functions in the extracellular space. Extracellular NAMPT (eNAMPT, also called visfatin or pre-B-cell colony enhancing factor) has been shown to possess adipocytokine, pro-inflammatory, and pro-angiogenic activities. Numerous studies have reported the association between elevated levels of circulating eNAMPT and various inflammatory and metabolic disorders such as obesity, diabetes, atherosclerosis, arthritis, inflammatory bowel disease, lung injury and cancer. In this review, we summarize the current state of knowledge on eNAMPT biology, proposed roles in disease pathogenesis, and its potential as a disease biomarker. We also briefly discuss the emerging therapeutic approaches for eNAMPT inhibition.

Visfatin upregulates VEGF-C expression and lymphangiogenesis in esophageal cancer by activating MEK1/2-ERK and NF-κB signaling

Lymph node metastasis is a recognized prognostic factor in esophageal cancer. Adipokines, including visfatin, and the molecule vascular endothelial growth factor (VEGF)-C, are implicated in lymphangiogenesis, but whether any association exists between esophageal cancer, adipokines and VEGF-C is unknown. We examined the relevance of adipokines and VEGF-C in esophageal squamous cell carcinoma (ESCC) in the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. We found significantly higher levels of visfatin and VEGF-C expression in esophageal cancer tissue than in normal tissue. Immunohistochemistry (IHC) staining identified that higher levels of visfatin and VEGF-C expression were correlated with advanced stage ESCC. Visfatin treatment of ESCC cell lines upregulated VEGF-C expression and VEGF-C-dependent lymphangiogenesis in lymphatic endothelial cells. Visfatin induced increases in VEGF-C expression by activating the mitogen-activated protein kinase kinases1/2-extracellular signal-regulated kinase (MEK1/2-ERK) and Nuclear Factor Kappa B (NF-κB) signaling cascades. Transfecting ESCC cells with MEK1/2-ERK and NF-κB inhibitors (PD98059, FR180204, PDTC, and TPCK) and siRNAs inhibited visfatin-induced increases in VEGF-C expression. It appears that visfatin and VEGF-C are promising therapeutic targets in the inhibition of lymphangiogenesis in esophageal cancer.

Nicotinamide Adenine Dinucleotide (NAD) Metabolism as a Relevant Target in Cancer

NAD+ is an important metabolite in cell homeostasis that acts as an essential cofactor in oxidation–reduction (redox) reactions in various energy production processes, such as the Krebs cycle, fatty acid oxidation, glycolysis and serine biosynthesis. Furthermore, high NAD+ levels are required since they also participate in many other nonredox molecular processes, such as DNA repair, posttranslational modifications, cell signalling, senescence, inflammatory responses and apoptosis. In these nonredox reactions, NAD+ is an ADP-ribose donor for enzymes such as sirtuins (SIRTs), poly-(ADP-ribose) polymerases (PARPs) and cyclic ADP-ribose (cADPRs). Therefore, to meet both redox and nonredox NAD+ demands, tumour cells must maintain high NAD+ levels, enhancing their synthesis mainly through the salvage pathway. NAMPT, the rate-limiting enzyme of this pathway, has been identified as an oncogene in some cancer types. Thus, NAMPT has been proposed as a suitable target for cancer therapy. NAMPT inhibition causes the depletion of NAD+ content in the cell, leading to the inhibition of ATP synthesis. This effect can cause a decrease in tumour cell proliferation and cell death, mainly by apoptosis. Therefore, in recent years, many specific inhibitors of NAMPT have been developed, and some of them are currently in clinical trials. Here we review the NAD metabolism as a cancer therapy target.

The HIF-1α as a Potent Inducer of the Hallmarks in Gastric Cancer

Hypoxia is the principal architect of the topographic heterogeneity in tumors. Hypoxia-inducible factor-1α (HIF-1α) reinforces all hallmarks of cancer and donates cancer cells with more aggressive characteristics at hypoxic niches. HIF-1α potently induces sustained growth factor signaling, angiogenesis, epithelial-mesenchymal transition, and replicative immortality. Hypoxia leads to the selection of cancer cells that evade growth suppressors or apoptotic triggers and deregulates cellular energetics. HIF-1α is also associated with genetic instability, tumor-promoting inflammation, and escape from immunity. Therefore, HIF-1α may be an important therapeutic target in cancer. Despite that, the drug market lacks safe and efficacious anti-HIF-1α molecules, raising the quest for fully unveiling the complex interactome of HIF-1α in cancer to discover more effective strategies. The knowledge gap is even wider in gastric cancer, where the number of studies on hypoxia is relatively low compared to other well-dissected cancers. A comprehensive review of the molecular mechanisms by which HIF-1α induces gastric cancer hallmarks could provide a broad perspective to the investigators and reveal missing links to explore in future studies. Thus, here we review the impact of HIF-1α on the cancer hallmarks with a specific focus on gastric cancer.

Updated Functional Roles of NAMPT in Carcinogenesis and Therapeutic Niches

Simple Summary

The advantages and applications of using the non-invasive way to detect serum biomarkers for assessing cancer diagnosis and prognosis have been explored. Nicotinamide phosphoribosyltransferase (NAMPT), also designated as pre-B-cell colony-enhancing factor (PBEF) or visfatin, is a secreted adipokine known to modulate tumor malignancies. Its significance in predicting cancer patient’s survival outcome further renders the implementation of NAMPT in clinical practice. In this review, recent discoveries of NAMPT in cancer studies were focused and integrated. We aim to provide updates for researchers who are proposing relevant objectives.

Abstract

Nicotinamide phosphoribosyltransferase (NAMPT) is notable for its regulatory roles in tumor development and progression. Emerging evidence regarding NAMPT somatic mutations in cancer patients, NAMPT expressional signatures in normal tissues and cancers, and the prognostic significance of NAMPT in many cancer types has attracted attention, and NAMPT is considered a potential biomarker of cancer. Recent discoveries have demonstrated the indirect association and direct biological functions of NAMPT in modulating cancer metastasis, proliferation, angiogenesis, cancer stemness, and chemoresistance to anticancer drugs. These findings warrant further investigation of the underlying mechanisms to provide knowledge for developing novel cancer therapeutics. In this review article, we explore recent research developments involving the oncogenic activities of NAMPT by summarizing current knowledge regarding NAMPT somatic mutations, clinical trials, transcriptome data, and clinical information and discoveries related to the NAMPT-induced signaling pathway in modulating hallmarks of cancer. Furthermore, the comprehensive representation of NAMPT RNA expression in a pancancer panel as well as in specific normal cell types at single-cell level are demonstrated. The results suggest potential sites and cell types that could facilitate NAMPT-related tumorigenesis. With this review, we aim to shed light on the regulatory roles of NAMPT in tumor development and progression, and provide information to guide future research directions in this field.

Novel Biomarkers of Gastric Adenocarcinoma: Current Research and Future Perspectives

Simple Summary

Gastric cancer is characterized by poor survival rates despite surgery and chemotherapy. Current research focuses on biomarkers to improve diagnosis and prognosis, and to enable targeted treatment strategies. The aim of our review was to give an overview over the wide range of novel biomarkers in gastric cancer. These biomarkers are targets of a specific treatment, such as antibodies against human epidermal growth factor receptor 2. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are vascular endothelial growth factor, programmed cell death protein 1, and Claudin 18.2. There is a vast number of biomarkers based on DNA, RNA, and protein expression, as well as detection of circulating tumor cells and the immune tumor microenvironment.

Abstract

Overall survival of gastric cancer remains low, as patients are often diagnosed with advanced stage disease. In this review, we give an overview of current research on biomarkers in gastric cancer and their implementation in treatment strategies. The HER2-targeting trastuzumab is the first molecular targeted agent approved for gastric cancer treatment. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are VEGF and Claudin 18.2. Expression of MET has been shown to be a negative prognostic factor in gastric cancer. Targeting the PD-1/PD-L1 pathway with immune checkpoint inhibitors has proven efficacy in advanced gastric cancer. Recent technology advances allow the detection of circulating tumor cells that may be used as diagnostic and prognostic indicators and for therapy monitoring in gastric cancer patients. Prognostic molecular subtypes of gastric cancer have been identified using genomic data. In addition, transcriptome profiling has allowed a comprehensive characterization of the immune and stromal microenvironment in gastric cancer and development of novel risk scores. These prognostic and predictive markers highlight the rapidly evolving field of research in gastric cancer, promising improved treatment stratification and identification of molecular targets for individualized treatment in gastric cancer.

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.

Visfatin facilitates gastric cancer malignancy by targeting snai1 via the NF-κB signaling

BACKGROUND

Visfatin acts as an oncogenic factor in numerous tumors through a variety of cellular processes. Visfatin has been revealed to promote cell migration and invasion in gastric cancer (GC). Snai1 is a well-known regulator of EMT process in cancers. However, the relationship between visfatin and snai1 in GC remains unclear. The current study aimed to explore the role of visfatin in GC.

METHODS

The RT-qPCR and western blot analysis were used to measure RNA and protein levels, respectively. The cell migration and invasion were tested by Trans-well assays and western blot analysis.

RESULTS

Visfatin showed upregulation in GC cells. Additionally, Visfatin with increasing concentration facilitated epithelial-mesenchymal transition (EMT) process by increasing E-cadherin and reducing N-cadherin and Vimentin protein levels in GC cells. Moreover, endogenous overexpression and knockdown of visfatin promoted and inhibited migratory and invasive abilities of GC cells, respectively. Then, we found that snai1 protein level was positively regulated by visfatin in GC cells. In addition, visfatin activated the NF-κB signaling to modulate snai1 protein expression. Furthermore, the silencing of snai1 counteracted the promotive impact of visfatin on cell migration, invasion and EMT process in GC.

CONCLUSION

Visfatin facilitates cell migration, invasion and EMT process by targeting snai1 via the NF-κB signaling, which provides a potential insight for the treatment of GC.

Obesity Potentiates Esophageal Squamous Cell Carcinoma Growth and Invasion by AMPK-YAP Pathway

Obesity could increase the risk of esophageal squamous cell carcinoma (ESCC) and affect its growth and progression, but the mechanical links are unclear. The objective of the study was to explore the impact of obesity on ESCC growth and progression utilizing in vivo trials and cell experiments in vitro. Diet-induced obese and lean nude mice were inoculated with TE-1 cells, then studied for 4 weeks. Serum glucose, insulin, leptin, and visfatin levels were assayed. Sera of nude mice were obtained and then utilized to culture TE-1. MTT, migration and invasion assays, RT-PCR, and Western blotting were used to analyze endocrine effect of obesity on cell proliferation, migration, invasion, and related genes expression of TE-1. Obese nude mice bore larger tumor xenografts than lean animals, and were hyperglycemic and hyperinsulinemic with an elevated level of leptin and visfatin in sera, and also were accompanied by a fatty liver. As for the subcutaneous tumor xenograft model, tumors were more aggressive in obese nude mice than lean animals. Tumor weight correlated positively with mouse body weight, liver weight of mice, serum glucose, HOMA-IR, leptin, and visfatin. Obesity prompted significant TE-1 cell proliferation, migration, and invasion by endocrine mechanisms and impacted target genes. The expression of AMPK and p-AMPK protein decreased significantly (P < 0.05); MMP9, total YAP, p-YAP, and nonphosphorylated YAP protein increased significantly (P < 0.05) in the cells cultured with conditioned media and xenograft tumor from the obese group; the mRNA expression of AMPK decreased significantly (P < 0.05); YAP and MMP9 mRNA expression increased significantly (P < 0.05) in the cells exposed to conditioned media from the obese group. In conclusion, the altered adipokine milieu and metabolites in the context of obesity may promote ESCC growth in vivo; affect proliferation, migration, and invasion of ESCC cells in vitro; and regulate MMP9 and AMPK-YAP signaling pathway through complex effects including the endocrine effect.

Changes in the localization of ovarian visfatin protein and its possible role during estrous cycle of mice

Visfatin is a crucial adipokine, which also regulates ovarian functions in many animals. Mice estrous cycle is characterized by a dynamic complex physiological process in the reproductive system. Expression of various factors changes during the estrous cycle in the ovary. To the best of our knowledge, no previous study has been conducted on the expression of visfatin in mice ovaries during the estrous cycle. Therefore, we investigated the localization and expression of visfatin protein in the ovary of mice during the estrous cycle. Western blot analysis showed the elevated expression of visfatin in proestrus and lowest in diestrus. Immunohistochemical localization of visfatin showed intense staining in the corpus luteum of proestrus and diestrus ovaries. Thecal cells, granulosa cells, and oocytes also showed the presence of visfatin. Expression of ovarian visfatin was correlated to BCL2 and active caspase3 expression and exhibited a significant positive correlation. Furthermore, in vivo inhibition of visfatin by FK866 in the proestrus ovary down-regulated active caspase3 and PCNA expression, and up-regulated the BCL2 expression. These results suggest the role of visfatin in the proliferation and apoptosis of the follicles and specific localization of visfatin in the corpus luteum also indicate its role in corpus luteum function, which may be in progesterone biosynthesis and regression of old corpus luteum. However, further study is required to support these findings. In conclusion, visfatin may also be regulating follicular growth during the estrous cycle by regulating proliferation and apoptosis.

Suppressed immune profile in children with combined type 1 diabetes and celiac disease

Children diagnosed with a combination of type 1 diabetes (T1D) and celiac disease (CD) show a dysregulated T helper type 1 (Th1)/Th17 response. Besides the cellular involvement, several soluble immune markers are involved in the autoimmune process of both T1D and CD. Only few studies have examined the peripheral pattern of different cytokines, chemokines and acute-phase proteins (APP) in children with combined T1D and CD. To our knowledge, no studies have evaluated the serum levels of adipocytokines and matrix metalloproteinases (MMPs) in this context. The purpose of the present study was to acquire more knowledge and to gain deeper understanding regarding the peripheral immunoregulatory milieu in children with both T1D and CD. The study included children diagnosed with both T1D and CD (n = 18), children with T1D (n = 27) or CD (n = 16) and reference children (n = 42). Sera were collected and analysis of 28 immune markers (cytokines, chemokines, APPs, adipocytokines and MMPs) was performed using the Luminex technique. The major findings showed that children with a double diagnosis had lower serum levels of interleukin (IL)-22, monocyte chemoattractant protein (MIP)-1α, monocyte chemoattractant protein (MCP)-1, procalcitonin, fibrinogen, visfatin and matrix metalloproteinase (MMP)-2. These results indicate a suppressed immune profile in children with combined T1D and CD, including Th17 cytokines, chemokines, APPs, adipocytokines and MMPs. We conclude that, besides cytokines and chemokines, other immune markers, e.g. APPs, adipocytokines and MMPs, are of importance for further investigations to elucidate the heterogeneous immune processes present in patients diagnosed with T1D in combination with CD.

Prognostic value of visfatin in various human malignancies: A systematic review and meta-analysis

Although numerous studies have shown that visfatin is linked to several cancers, its prognostic value is still unclear. This first comprehensive meta-analysis was performed to evaluate the prognostic effect of visfatin in cancer patients. A systematic search was conducted for relevant studies in health-related electronic databases up to May 2019. The pooled hazard ratios (HRs) and ORs with 95% confidence intervals (CIs) for total and stratified analyses were calculated to demonstrate the prognostic value of visfatin expression level in cancer patients. Heterogeneity and publication bias were also investigated. A total of 14 eligible studies with 1616 patients were included in the current meta-analysis. Pooling results revealed that, high visfatin expression was significantly associated with poorer overall survival (OS) (HR = 2.43, 95% CI 1.64-3.62, P < 0.001). Elevated visfatin level was also correlated with positive lymph node metastasis (OR = 2.45, 95% CI 1.43-4.17, P ≤ 0.001), positive distance metastasis (OR = 2014, 95% CI 1.25-3.69, P ≤ 0.001), advanced tumor stage (OR = 3.01, 95% CI 1.91-7.72, P ≤ 0.001), and larger tumor size (OR = 1.99, 95% CI 1.49-2.69, P ≤ 0.001). Our meta-results indicates that altered visfatin expression is a potential indicator of poor clinical outcomes in tumor patients, suggesting that high visfatin expression may serve as a potential biomarker of poor prognosis and metastasis in cancers.

Relationship between NAMPT/PBEF/visfatin and prognosis of patients with malignant tumors: a systematic review and meta-analysis

Background

Nicotinamide phosphoribosyltransferase (NAMPT), also known as pre-B-cell colony-enhancing factor (PBEF) or visfatin, has been reported to be a crucial factor involved in tumor metabolism, angiogenesis and cell apoptosis. However, its definite roles in patients with malignant cancer remain unclear.

Methods

Three online databases PubMed, Embase and Web of Science were looked through comprehensively for eligible articles, published before November, 2018. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) of overall survival (OS) or disease-free survival time or recurrence-free survival (DFS/RFS) were calculated to determine the associations between NAMPT expression and cancer prognosis.

Results

A total of ten eligible studies were finally enrolled for this analysis. Our results indicated that elevated NAMPT expression was associated with poor OS in breast cancer by both univariate and multivariate analysis (pooled HR =3.23, 95% CI: 1.93-5.41, I²=21.1%, P=0.283; pooled HR =3.34, 95% CI: 2.13-5.22, I²=0.0%, P=0.791; respectively) and in gastric cancer by univariate analysis (pooled HR =2.47, 95% CI: 1.07-5.73, I²=91.1%, P=0.001). Moreover, high expression of NAMPT was also related to poor DFS/RFS in breast cancer by univariate and multivariate analysis (pooled HR =3.85, 95% CI: 2.59-5.71, I²=0.0%, P=0.700; pooled HR =3.43, 95% CI: 2.36-4.99, I²=0.0%, P=0.737; separately). Similar results could be found in urothelial carcinoma (pooled HR =3.14, 95% CI: 1.73-5.71, I²=47.8%, P=0.166; pooled HR =3.06, 95% CI: 1.57-5.98, I²=0.0%, P=0.860). Besides, the translational level of NAMPT was also validated by UALCAN and the Human Protein Atlas database [immunohistochemistry (IHC)].

Conclusions

Our results shed light on that NAMPT might be an oncogenic factor in breast cancer, gastric cancer and urothelial carcinoma.

The role of visfatin in cancer proliferation, angiogenesis, metastasis, drug resistance and clinical prognosis

Visfatin, also known as nicotinamide phosphoribosyltransferase or pre-B-cell colony-enhancing factor (PBEF), is an adipocytokine secreted by adipocytes, macrophages and inflamed endothelial tissue. Related reports have indicated a positive correlation between the visfatin level and obesity and cancer risk. In addition to its original function, visfatin is multifunctional and plays critical roles in the promotion of several processes relevant to cancer progression including cancer cell proliferation, angiogenesis, metastasis and drug resistance. The relative expression of visfatin and the potential visfatin receptor on a pan-cancer scale was determined based on the transcriptome analysis data in The Cancer Genome Atlas. We further show the clinical association of its signaling axis with the survival of cancer patients, which reveals its prognostic power for specific cancer types. This review illustrates visfatin’s biological functions related to cancer progression and demonstrates its clinical significance in predicting outcomes of cancer patients.

Circulating visfatin levels and cancers risk: A systematic review and meta-analysis

Visfatin levels have been reported to be abnormal in many types of cancers. However, epidemiological studies yielded inconsistent results. Therefore, a meta-analysis was performed to assess the association between circulating visfatin levels and cancer risk. A systematic search was conducted for relevant studies in health-related electronic databases up to March 2018. Data related to standard mean difference (SMD) and overall odds ratio (ORS) were collected and analyzed. Summary SMD and pooled OR with 95% CIs were calculated using a random-effect model. Funnel plot and Egger's linear regression test were conducted to examine the risk of publication bias. A total of 27 studies with 2,693 cases and 3,040 healthy controls were included in meta-analysis for pooling SMD analysis. The results of the meta-analysis showed a significant higher visfatin levels in patients with various cancers than in controls, with a pooled SMD of 0.88, 95% CI = 0.56-1.20, p = 0.000. In subgroup, metaregression, Galbraith plot, and sensitivity analysis showed no substantial difference among all the analyzed factors. Data from 14 studies were also used for pooling ORs analysis. Metaresults revealed that high visfatin levels were associated with cancer risk (OR = 1.24, 95% CI: 1.14-1.34, p = 0.000). No evidence of publication bias was observed for pooling ORs and SMD analysis. This meta-analysis indicated a significant association between high circulating visfatin levels and increased risk of various cancers. Visfatin may represent a potential biomarker for early detection of cancers who may benefit from preventive treatment.Note.

NAD+Metabolism in Aging and Cancer

Aging is a major risk factor for many types of cancer, and the molecular mechanisms implicated in aging, progeria syndromes, and cancer pathogenesis display considerable similarities. Maintaining redox homeostasis, efficient signal transduction, and mitochondrial metabolism is essential for genome integrity and for preventing progression to cellular senescence or tumorigenesis. NAD+is a central signaling molecule involved in these and other cellular processes implicated in age-related diseases and cancer. Growing evidence implicates NAD+decline as a major feature of accelerated aging progeria syndromes and normal aging. Administration of NAD+precursors such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) offer promising therapeutic strategies to improve health, progeria comorbidities, and cancer therapies. This review summarizes insights from the study of aging and progeria syndromes and discusses the implications and therapeutic potential of the underlying molecular mechanisms involved in aging and how they may contribute to tumorigenesis.

Underrated enemy - from nonalcoholic fatty liver disease to cancers of the gastrointestinal tract

Nonalcoholic fatty liver disease (NAFLD) is intrahepatic ectopic lipid deposition which is present despite a lack of other causes of secondary hepatic fat accumulation. It is the most common chronic liver disorder in the welldeveloped countries. NAFLD is a multidisciplinary disease that affects various systems and organs and is inextricably linked to simple obesity, metabolic syndrome, insulin resistance and overt diabetes mellitus type 2. The positive energy balance related to obesity leads to a variety of systemic changes including modified levels of insulin, insulin- like growth factor-1, adipokines, hepatokines and cytokines. It is strongly linked to carcinogenesis and new evidence proves that NAFLD is associated with higher risk of all-cause mortality and cancer-specific mortality among cancer survivors. This article focuses on the association between NAFLD and extrahepatic gastrointestinal tract cancers, aiming to shed light on the pathomechanism of changes leading to the development of tumors.

The role of extracellular and intracellular Nicotinamide phosphoribosyl-transferase in cancer: Diagnostic and therapeutic perspectives and challenges

Nicotinamide phosphoribosyl-transferase (Nampt) or pre-B cell colony-enhancing factor or visfatin represents a pleiotropic molecule acting as an enzyme, a cytokine and a growth factor. Intracellular Nampt plays an important role in cellular bioenergetics and metabolism, particularly NAD biosynthesis. NAD biosynthesis is critical in DNA repair, oncogenic signal transduction, transcription, genomic integrity and apoptosis. Although its insulin-mimetic function remains a controversial issue, extracellular Nampt presents proliferative, anti-apoptotic, pro-inflammatory, pro-angiogenic and metastatic properties. Nampt is upregulated in many malignancies, including obesity-associated cancers, and is associated with worse prognosis. Serum Nampt may be a potential diagnostic and prognostic biomarker in cancer. Pharmacologic agents that neutralize Nampt or medications that decrease Nampt levels or downregulate signaling pathways downstream of Nampt may prove to be useful anti-cancer treatments. In particular, Nampt inhibitors as monotherapy or in combination therapy have displayed anti-cancer activity in vivo and in vitro. The aim of this review is to explore the role of Nampt in cancer pathophysiology as well as to synopsize the mechanisms underlying the association between extracellular and intracellular Nampt, and malignancy. Exploring the interplay of cellular bioenergetics, inflammation and adiposopathy is expected to be of importance in the development of preventive and therapeutic strategies against cancer.

Elevated serum visfatin levels are associated with poor prognosis of hepatocellular carcinoma

Visfatin is considered a pro-inflammatory adipocytokine, and it is commonly increased in obesity-related diseases. This study aimed to evaluate the levels of serum visfatin in patients with hepatocellular carcinoma (HCC) and its diagnostic and predictive value in detecting HCC. Fasting serum levels of visfatin of 135 HCC patients, 115 chronic hepatitis B (CHB) patients, 129 liver cirrhosis (LC) patients, and 149 healthy controls were determined via enzyme-linked immunosorbent assay. Meanwhile, serum alpha fetal protein (AFP) and interleukin-6 (IL-6) were also assayed. The median serum visfatin concentration in HCC patients was 1.113 ng/mL (range: 0.823-2.214 ng/mL), which was significant higher than those of healthy controls, CHB patients, and LC patients (P<0.05). The serum visfatin concentration in HCC patients was positively correlated with AFP (r=0.595, P<0.001) and IL-6 (r=0.261, P<0.015) and was also associated with tumor size and tumor node metastasis stage. Moreover, elevated levels of serum visfatin were associated with a higher HCC risk for CHB and LC patients. Multivariate Cox regression analysis had shown that HCC patients with high levels of serum visfatin had significantly shorter overall survival times than those with low serum visfatin levels (P<0.001). Using a cutoff visfatin level of 1.403 ng/mL, the receiver operating characteristic curve analysis showed unappealing sensitivity and specificity values (45.76% and 74.79%, respectively; AUC=0.626) regarding visfatin's use as a diagnostic marker for HCC. Our results indicate that increased serum visfatin levels are associated with poor prognosis of HCC. Visfatin may be a potential therapeutic target of HCC.

Association of leptin, visfatin, apelin, resistin and adiponectin with clear cell renal cell carcinoma

Although an association between obesity and the occurrence of renal cell carcinoma (RCC) has been identified, the mechanism by which obesity functions to increase this risk of cancer remains unclear. Leptin, visfatin, apelin, resistin and adiponectin are peptide hormones secreted by adipocytes; it is considered that these may affect RCC development by exerting effects on proliferation, cell growth and inflammation. The aim of the present study was to investigate the association between the aforementioned adipokine genes and clear cell RCC (CC-RCC). The GSE6344 dataset was downloaded from the Gene Expression Omnibus database, and the relative expression levels of the adipokine genes were analyzed. To verify the results of the mRNA microarray, 77 paired samples of CC-RCC and corresponding adjacent normal tissue were allocated into two groups. The extraction of total RNA was conducted, and the mRNA expression of adipokine genes was analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The data from the GSE6344 dataset indicated that the expression of visfatin and apelin was upregulated (P<0.0001 and P<0.01, respectively), and adiponectin was downregulated (P<0.001) in the CC-RCC tissues compared with the adjacent normal tissues. The data from RT-qPCR demonstrated that visfatin and resistin gene expression was increased (P<0.01 and P<0.05, respectively) in the CC-RCC tissues. Furthermore, the mRNA expression level of leptin and adiponectin in the adjacent normal tissue was higher than those in the cancer tissue (P<0.01). The current study verifies that visfatin and adiponectin are associated with an increased risk of CC-RCC, which presents further insights into the molecular mechanisms of CC-RCC tumorigenesis.

Extracellular nicotinamide phosphoribosyltransferase, a new cancer metabokine

In this review, we focus on the secreted form of nicotinamide phosphoribosyltransferase (NAMPT); extracellular NAMPT (eNAMPT), also known as pre-B cell colony-enhancing factor or visfatin. Although intracellular NAMPT is a key enzyme in controlling NAD metabolism, eNAMPT has been reported to function as a cytokine, with many roles in physiology and pathology. Circulating eNAMPT has been associated with several metabolic and inflammatory disorders, including cancer. Because cytokines produced in the tumour micro-environment play an important role in cancer pathogenesis, in part by reprogramming cellular metabolism, future improvements in cancer immunotherapy will require a better understanding of the crosstalk between cytokine action and tumour biology. In this review, the knowledge of eNAMPT in cancer will be discussed, focusing on its immunometabolic function as a metabokine, its secretion, its mechanism of action and possible roles in the cancer micro-environment.

Identifying the emerging role of adipokine as a diagnostic and prognostic biomarker of renal cell carcinoma

OBJECTIVE

To assess the association and prognostic value of adipokines (adipocyte-secreted peptide hormones) in renal cell carcinoma (RCC).

MATERIALS AND METHODS

Plasma samples from 54 RCC patients and 25 age-matched healthy controls were analyzed for levels of adipokines (adiponectin, leptin, retinol-binding protein 4 [RBP4], and nicotinamide phosphoribosyltransferase [NAMPT]). Baseline characteristics and adipokine levels were compared between patients and controls. The effect of adipokine levels on RCC severity was also investigated.

RESULTS

Medians (patients/controls) were body mass index: 24.6/23.5kg/m(2), serum glucose: 111/93mg/dl, and high-density lipoprotein: 43/53mg/dl, and significantly differed between the 2 groups. Median levels (patients/controls) of adipokines were adiponectin: 4.36/8.84ug/ml, leptin: 2.91/2.92ng/ml, RBP4: 30.27/16.17ug/ml and NAMPT: 2.26/2.06ng/ml; adiponectin, RBP4 and NAMPT (but not leptin) were independently associated with RCC in logistic regression models, and only serum NAMPT was significantly associated with RCC severity (T stage).

CONCLUSIONS

Lower plasma levels of adiponectin, and higher levels of RBP4 and NAMPT, are strongly correlated with RCC, indicating that these adipokines could be used as biomarkers for RCC.

High-visfatin levels in women with polycystic ovary syndrome: evidence from a meta-analysis

OBJECTIVE

Previous studies regarding visfatin levels in women with polycystic ovary syndrome (PCOS) showed conflicting results. To evaluate the visfatin levels in PCOS, a meta-analysis was performed.

METHODS

A comprehensive literature search of eligible studies in Embase, Pubmed and the Cochrane Library was undertaken through November 2014. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association.

RESULTS

A total of 1341 subjects (695 cases and 646 controls) were included in this meta-analysis. The pooled analysis results indicated that the visfatin levels were significantly higher in PCOS patients than that of controls (SMD = 1.19, 95% CI 0.77-1.60, p = 0.000). The results from stratified analysis and univariate analysis suggested that high-visfatin levels were not related to body mass index (BMI), insulin resistance (IR) and total testosterone ratio. Significant heterogeneity was observed in all analysis.

CONCLUSION

Our results indicate that high-circulating visfatin level is an intrinsic characteristic of PCOS, which suggests visfatin could be a potential biomarker for PCOS.

Regulative Effect of Nampt on Tumor Progression and Cell Viability in Human Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer disease. Here we examined Nampt expression in patients with CRC and the effect of Nampt on cell viability in CRC cells. Nampt protein was overexpressed in colorectal adenoma as well as colorectal carcinoma. The immunoreactive staining of Nampt was negative in the adjacent normal colorectal tissue, weak in colorectal adenoma, and strong in colorectal carcinoma, which may represent tumor progression. Further evaluation of clinical data showed that Nampt expression was not correlated with the clinicopathological characteristics of CRC. Additionally, our in vitro studies demonstrated that Nampt promotes CRC cell viability, whereas the Nampt inhibitor FK866 suppressed CRC cell viability, which was in concordance with the previous studies in other cancer cells. Treatment with Nampt-siRNA reduced the Nampt protein expression resulting in the inhibition of the cell viability of HCT116 and Caco2. Thus, the involvement of Nampt in cell growth indicates that Nampt may play an important role in colorectal tumorigenesis. As a consequence, our results suggest that Nampt may be considered as a progression marker of colorectal tumor and a potentially therapeutic target for the treatment of CRC.

The prognostic value of intermedin in patients with breast cancer

This study aimed to evaluate the prognostic value of preoperative plasma intermedin levels in breast cancer patients. Plasma intermedin levels of 252 breast cancer women and 100 healthy women were determined using radioimmunoassay kit. Adverse event was defined as first local recurrence, distant metastasis, second primary cancer of another organ, or death from any cause during 5-year follow-up. Disease-free survival was defined as the time between surgery and the date of any adverse event whichever appeared first. Overall survival was defined from surgery to death for any cause. The relationships between plasma intermedin levels and clinical outcomes of breast cancer patients were evaluated using multivariate analysis. The results showed that preoperative plasma intermedin levels were substantially higher in patients than in healthy subjects using t-test. Intermedin was identified as an independent predictor for 5-year mortality, adverse event, disease-free survival, and overall survival using multivariate analysis. Based on receiver operating characteristic curve analysis, preoperative plasma intermedin levels had high predictive value for 5-year mortality and adverse event. In conclusion, preoperative plasma intermedin levels are highly associated with poor patient outcomes and intermedin may be a potential prognostic biomarker for patients with breast cancer.

Prognostic significance of plasma chemerin levels in patients with gastric cancer

Chemerin is a novel adipokine, which is linked to adipogenesis and chemotaxis of the innate immune system. This study aimed to evaluate the relationship between preoperative plasma chemerin level and prognosis of gastric cancers. One hundred ninety-six patients and 196 age- and gender-matched healthy individuals were recruited. Fasting venous blood samples were collected 2 days prior to surgery for the gastric cancer patients and at the physical examination day for the healthy volunteers. Recorded clinicopathological information included invasion depth, lymph node metastasis, distant metastasis, peritoneal dissemination, tumor size and tumor-node metastasis stage. Plasma chemerin levels were determined using enzyme-linked immunosorbent assay. Plasma chemerin levels were statistically significantly in all patients than in healthy controls (53.1 ± 19.0 ng/mL vs. 31.3 ± 11.3 ng/mL; P < 0.001). And it was identified as an independent predictor for 5-year mortality [odds ratio (OR), 2.718; 95% confidence interval (CI), 1.201-4.229; P = 0.005) and adverse event (OR, 2.982; 95% CI, 1.223-4.879; P = 0.003) of gastric cancer, and had high area under receiver operating characteristic curve (AUC) for prediction of 5-year mortality (AUC, 0.808; 95% CI, 0.745-0.860) and adverse event (AUC, 0.787; 95% CI, 0.723-0.842). It also emerged as an independent predictor for overall survival (Hazard ratios, 1.788; 95% CI, 1.200-2.663; P = 0.002) and disease-free survival (Hazard ratios, 2.016; 95% CI, 1.312-3.125; P = 0.004). Thus, our results suggest that high plasma chemerin levels are associated with long-term poor prognosis and survival of gastric cancer as well as may play a role as prognostic biomarker in gastric cancer survival.