Visfatin promotes osteosarcoma cell migration and invasion via induction of epithelial-mesenchymal transition

Targeting NAD+ metabolism: dual roles in cancer treatment

Nicotinamide adenine dinucleotide (NAD+) is indispensable for various oxidation-reduction reactions in mammalian cells, particularly during energy production. Malignant cells increase the expression levels of NAD+ biosynthesis enzymes for rapid proliferation and biomass production. Furthermore, mounting proof has indicated that NAD-degrading enzymes (NADases) play a role in creating the immunosuppressive tumor microenvironment (TME). Interestingly, both inhibiting NAD+ synthesis and targeting NADase have positive implications for cancer treatment. Here we summarize the detrimental outcomes of increased NAD+ production, the functions of NAD+ metabolic enzymes in creating an immunosuppressive TME, and discuss the progress and clinical translational potential of inhibitors for NAD+ synthesis and therapies targeting NADase.

Adipokines and epithelial-mesenchymal transition (EMT) in cancer

Obesity is a significant risk factor for cancer development. Within the tumor microenvironment, adipocytes interact with cancer cells, immune cells, fibroblasts and endothelial cells, and orchestrate several signaling pathways by secreting bioactive molecules, including adipokines. Adipokines or adipocytokines are produced predominantly by adipocytes and function as autocrine, paracrine and endocrine mediators. Adipokines can exert pro- and anti-inflammatory functions, and they play a pivotal role in the state of chronic low-grade inflammation that characterizes obesity. Epithelial-mesenchymal transition (EMT), a complex biological process whereby epithelial cells acquire the invasive, migratory mesenchymal phenotype is well-known to be implicated in cancer progression and metastasis. Emerging evidence suggests that there is a link between adipokines and EMT. This may contribute to the correlation that has been documented between obesity and cancer progression. This review summarizes the existing body of evidence supporting an association between the process of EMT in cancer and the adipokines leptin, adiponectin, resistin, visfatin/NAMPT, lipocalin-2/NGAL, as well as other newly discovered adipokines including chemerin, nesfatin-1/nucleobindin-2, AZGP1, SFRP5 and FABP4.

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.

Extracellular nicotinamide phosphoribosyltransferase (eNAMPT) neutralization counteracts T cell immune evasion in breast cancer

BACKGROUND

Nicotinamide phosphoribosyltransferase (NAMPT) is a key intracellular enzyme that participates in nicotinamide adenine dinucleotide (NAD) homeostasis as well as a released cytokine (eNAMPT) that is elevated in inflammatory conditions and in cancer. In patients with breast cancer, circulating eNAMPT is elevated and its plasma levels correlate with prognosis and staging. In light of this, we investigated the contribution of eNAMPT in triple negative mammary carcinoma progression by investigating the effect of its neutralization via a specific neutralizing monoclonal antibody (C269).

METHODS

We used female BALB/c mice injected with 4T1 clone 5 cells and female C57BL6 injected with EO771 cells, evaluating tumoral size, spleen weight and number of metastases. We injected two times a week the anti-eNAMPT neutralizing antibody and we sacrificed the mice after 28 days. Harvested tumors were analyzed by histopathology, flow cytometry, western blot, immunohistochemistry, immunofluorescence and RNA sequencing to define tumor characteristics (isolating tumor infiltrating lymphocytes and tumoral cells) and to investigate the molecular mechanisms behind the observed phenotype. Moreover, we dissected the functional relationship between T cells and tumoral cells using three-dimensional (3D) co-cultures.

RESULTS

The neutralization of eNAMPT with C269 led to decreased tumor size and reduced number of lung metastases. RNA sequencing and functional assays showed that eNAMPT controlled T-cell response via the programmed death-ligand 1/programmed cell death protein 1 (PD-L1/PD-1) axis and its neutralization led to a restoration of antitumoral immune responses. In particular, eNAMPT neutralization was able to activate CD8+IFNγ+GrzB+ T cells, reducing the immunosuppressive phenotype of T regulatory cells.

CONCLUSIONS

These studies indicate for the first time eNAMPT as a novel immunotherapeutic target for triple negative breast cancer.

Regulation of the Epithelial to Mesenchymal Transition in Osteosarcoma

The epithelial to mesenchymal transition (EMT) is a cellular process that has been linked to the promotion of aggressive cellular features in many cancer types. It is characterized by the loss of the epithelial cell phenotype and a shift to a more mesenchymal phenotype and is accompanied by an associated change in cell markers. EMT is highly complex and regulated via multiple signaling pathways. While the importance of EMT is classically described for carcinomas-cancers of epithelial origin-it has also been clearly demonstrated in non-epithelial cancers, including osteosarcoma (OS), a primary bone cancer predominantly affecting children and young adults. Recent studies examining EMT in OS have highlighted regulatory roles for multiple proteins, non-coding nucleic acids, and components of the tumor micro-environment. This review serves to summarize these experimental findings, identify key families of regulatory molecules, and identify potential therapeutic targets specific to the EMT process in OS.

Addressing the Enzyme-independent tumor-promoting function of NAMPT via PROTAC-mediated degradation

Aberrant overexpression of nicotinamide phosphoribosyltransferase (NAMPT) has been reported in a variety of tumor cells and is a poor prognosis factor for patient survival. It plays an important role in tumor cell proliferation, acting concurrently as an nicotinamide adenine dinucleotide (NAD⁺) synthase and, unexpectedly, as an extracellular signaling molecule for several tumor-promoting pathways. Although previous efforts to modulate NAMPT activity were limited to enzymatic inhibitors with low success in clinical studies, protein degradation offers the possibility to simultaneously disrupt NAMPT's enzyme activity and ligand capabilities. Here we report the development of two highly selective proteolysis-targeting chimeras (PROTACs) that promote NAMPT degradation in a cereblon-dependent manner. Both PROTAC degraders outperform a clinical candidate, FK866, in killing effect on hematological tumor cells. These results emphasize the importance and feasibility of applying PROTACs as a superior strategy for targeting proteins with multiple tumor-promoting functions like NAMPT, which is not easily achieved by conventional enzymatic inhibitors.

Comprehensive analysis of potential cellular communication networks in advanced osteosarcoma using single-cell RNA sequencing data

Osteosarcoma (OS) is a common bone cancer in children and adolescents, and metastasis and recurrence are the major causes of poor treatment outcomes. A better understanding of the tumor microenvironment is required to develop an effective treatment for OS. In this paper, a single-cell RNA sequencing dataset was taken to a systematic genetic analysis, and potential signaling pathways linked with osteosarcoma development were explored. Our findings revealed 25 clusters across 11 osteosarcoma tissues, with 11 cell types including “Chondroblastic cells”, “Osteoblastic cells”, “Myeloid cells”, “Pericytes”, “Fibroblasts”, “Proliferating osteoblastic cells”, “Osteoclasts”, “TILs”, “Endothelial cells”, “Mesenchymal stem cells”, and “Myoblasts”. The results of Cell communication analysis showed 17 potential cellular communication networks including “COLLAGEN signaling pathway network”, “CD99 signaling pathway network”, “PTN signaling pathway network”, “MIF signaling pathway network”, “SPP1 signaling pathway network”, “FN1 signaling pathway network”, “LAMININ signaling pathway network”, “FGF signaling pathway network”, “VEGF signaling pathway network”, “GALECTIN signaling pathway network”, “PERIOSTIN signaling pathway network”, “VISFATIN signaling pathway network”, “ITGB2 signaling pathway network”, “NOTCH signaling pathway network”, “IGF signaling pathway network”, “VWF signaling pathway network”, “PDGF signaling pathway network”. This research may provide novel insights into the pathophysiology of OS’s molecular processes.

Mechanism research and treatment progress of NAD pathway related molecules in tumor immune microenvironment

Nicotinamide adenine dinucleotide (NAD) is the core of cellular energy metabolism. NAMPT, Sirtuins, PARP, CD38, and other molecules in this classic metabolic pathway affect many key cellular functions and are closely related to the occurrence and development of many diseases. In recent years, several studies have found that these molecules can regulate cell energy metabolism, promote the release of related cytokines, induce the expression of neoantigens, change the tumor immune microenvironment (TIME), and then play an anticancer role. Drugs targeting these molecules are under development or approved for clinical use. Although there are some side effects and drug resistance, the discovery of novel drugs, the development of combination therapies, and the application of new technologies provide solutions to these challenges and improve efficacy. This review presents the mechanisms of action of NAD  pathway-related molecules in tumor immunity, advances in drug research, combination therapies, and some new technology-related therapies.

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.

Another Weapon against Cancer and Metastasis: Physical-Activity-Dependent Effects on Adiposity and Adipokines

Physically active behavior has been associated with a reduced risk of developing certain types of cancer and improved psychological conditions for patients by reducing anxiety and depression, in turn improving the quality of life of cancer patients. On the other hand, the correlations between inactivity, sedentary behavior, and overweight and obesity with the risk of development and progression of various cancers are well studied, mainly in middle-aged and elderly subjects. In this article, we have revised the evidence on the effects of physical activity on the expression and release of the adipose-tissue-derived mediators of low-grade chronic inflammation, i.e., adipokines, as well as the adipokine-mediated impacts of physical activity on tumor development, growth, and metastasis. Importantly, exercise training may be effective in mitigating the side effects related to anti-cancer treatment, thereby underlining the importance of encouraging cancer patients to engage in moderate-intensity activities. However, the strong need to customize and adapt exercises to a patient’s abilities is apparent. Besides the preventive effects of physically active behavior against the adipokine-stimulated cancer risk, it remains poorly understood how physical activity, through its actions as an adipokine, can actually influence the onset and development of metastases.

Beyond Energy Metabolism: Exploiting the Additional Roles of NAMPT for Cancer Therapy

Tumor cells have increased requirements for NAD⁺. Thus, many cancers exhibit an increased reliance on NAD⁺ production pathways. This dependence may be exploited therapeutically through pharmacological targeting of NAMPT, the rate-limiting enzyme in the NAD⁺ salvage pathway. Despite promising preclinical data using NAMPT inhibitors in cancer models, early NAMPT inhibitors showed limited efficacy in several early phase clinical trials, necessitating the identification of strategies, such as drug combinations, to enhance their efficacy. While the effect of NAMPT inhibitors on impairment of energy metabolism in cancer cells has been well-described, more recent insights have uncovered a number of additional targetable cellular processes that are impacted by inhibition of NAMPT. These include sirtuin function, DNA repair machinery, redox homeostasis, molecular signaling, cellular stemness, and immune processes. This review highlights the recent findings describing the effects of NAMPT inhibitors on the non-metabolic functions of malignant cells, with a focus on how this information can be leveraged clinically. Combining NAMPT inhibitors with other therapies that target NAD⁺-dependent processes or selecting tumors with specific vulnerabilities that can be co-targeted with NAMPT inhibitors may represent opportunities to exploit the multiple functions of this enzyme for greater therapeutic benefit.

Visfatin is involved in the cisplatin resistance of osteosarcoma cells via upregulation of Snail and Zeb1

Understanding the mechanisms of chemoresistance in osteosarcoma (OS) cell is important for drug development. By establishment of cisplatin (CDDP) resistant OS cells, we found that the levels of visfatin in OS/CDDP cells were significantly greater than that in their parental cells. The CDDP resistant OS cells showed greater migration and invasion capability than that of parental cells. Knockdown of visfatin can rescue the CDDP sensitivity of resistant OS cells. Among the detected epithelial-mesenchymal transition-related transcription factors (EMT-TFs), visfatin can increase the expression of Snail and Zeb-1 in OS cells. Overexpression of Snail and Zeb1 can attenuate si-visfatin reduced CDDP resistance of OS cells. Mechanistical studies indicated that visfatin can increase the mRNA expression of Snail and therefore upregulate its expression via HIF-1α induced transcription. As to Zeb1, visfatin had no effect on its mRNA expression, while significantly increased its protein stability. Furthermore, the upregulation of ATM, which can phosphorylate and stabilize Zeb1, was involved in visfatin-induced Zeb1 expression in OS cells. Collectively, our revealed that visfatin was involved in CDDP resistance of OS cells via upregulation of Snail and Zeb1, suggesting that inhibition of visfatin might be a potential pathway for OS treatment.

LncRNA, CRNDE promotes osteosarcoma cell proliferation, invasion and migration by regulating Notch1 signaling and epithelial-mesenchymal transition

Osteosarcoma is the most common bone malignancy in adolescence. Recently, the long non-coding RNAs (lncRNAs) were reported to play important roles in osteosarcoma progression. The present study examined the potential role of the lncRNA, Colorectal Neoplasia Differentially Expressed (CRNDE) and molecular mechanisms underlying osteosarcoma progression. In the present study, we identified that CRNDE was up-regulated in osteosarcoma tissues and cell lines, and CRNDE expression level was significantly higher in osteosarcoma tissues from patients with advanced stage and metastasis. Overexpression of CRNDE promoted cell growth, cell proliferation, cell invasion and migration, and increased cell population at S phase with a decreased cell population at G₀/G₁ phase in MG-63 cells. Knock-down of CRNDE suppressed cell growth, cell proliferation, cell invasion and migration, and decreased cell population at S phase with an increased cell population at G₀/G₁ phase in U2OS cells. Overexpression of CRNDE was found to enhance the activity of Notch1 signaling and promote epithelial-mesenchymal transition (EMT) in MG-63 cells, while knock-down of CRNDE exerted the opposite effects in U2OS cells. The in vivo results showed that knock-down of CRNDE suppressed the tumor growth in the nude mice inoculated with osteosarcoma cells, and knock-down of CRNDE also suppressed the mRNA expression of Notch1, JAG1, N-cadherin, vimentin, and increased the mRNA expression of E-cadherin in the tumor tissues. Collectively, our results indicated that CRNDE functioned as an oncogene in osteosarcoma cell lines, and CRNDE may exert its oncogenic role via regulating Notch1 signaling and EMT in osteosarcoma.

Transforming growth factor-β1 signaling promotes epithelial-mesenchymal transition-like phenomena, cell motility, and cell invasion in synovial sarcoma cells

The epithelial-to-mesenchymal transition (EMT) and the reverse process (the mesenchymal-to-epithelial transition [MET]) have been shown to be associated with tumor cell invasion and metastasis in different carcinomas. The EMT and MET have recently been shown to play a key role in the pathogenic processes of sarcomas, which are completely different from those of carcinomas. However, the definitive roles of the EMT in the tumorigenesis of synovial sarcomas remain unknown. Here, we explored whether transforming growth factor (TGF)-β signaling, an important oncogenic event in synovial sarcoma, modulates tumor cell characteristics related to the EMT, such as cell adhesion, migration, invasion, and proliferation. Interestingly, we found that TGF-β1 induced tumor cell activation, resulting in a tendency to aggregate and biphasic-like features. TGF-β1 also caused downregulation of E-cadherin and subsequent upregulation of N-cadherin, Snail, and Slug, which are responsible for EMT-like phenomena and increased cell motility and invasion. To further investigate the roles of TGF-β1 in the EMT, we established a SW982 cell line with stable TGF-β1 inhibition viaSB431542.These cells exhibited significantly decreased motility, migration, and proliferation (P = 0.001). Taken together, our data demonstrated that alterations in the TGF-β1/Smad signaling pathway could regulate the expression of EMT-related factors and the EMT process, resulting in changes in tumor cell invasion, migration, and proliferation in synovial sarcoma cells. These results may provide a important insights into therapeutic interventions and contribute to the present understanding of tumor progression in patients.

SphK1 modulates cell migration and EMT-related marker expression by regulating the expression of p-FAK in colorectal cancer cells

Sphingosine kinase 1 (SphK1) plays an important role in colorectal carcinoma metastasis. However, whether SphK1 modulates epithelial-mesenchymal transition (EMT)-related marker expression and the underlying mechanisms remain unclear. In this study, in order to clarify this issue, we used various colorectal cancer (CRC) cell lines, Caco2, HT29, RKO and HCT116. Each of the cell lines was divided into 3 groups as follows: the control group, SKI-Ⅱ (SphK1 inhibitor) group and PF-562271 [focal adhesion kinase (FAK) inhibitor] group. The migratory ability of the cells was examined by Transwell chamber assay. The mRNA and protein expression levels of SphK1, FAK (p-FAK), Slug, vimentin, N-cadherin and E-cadherin were detected by PCR and western blot analysis, respectively. The results revealed that the suppression of SphK1 reduced the cell migratory ability, and decreased the expression of Slug, vimentin and N-cadherin; however, the expression of E-cadherin was increased. Moreover, the inhibition of SphK1 reduced the expression of p-FAK. The inhibition of FAK (p-FAK) also decreased the cell migratory ability, and decreased the expression of Slug, vimentin and N-cadherin, whereas the expression of E-cadherin was increased. Thus, our data suggest that SphK1 modulates the expression of EMT-related markers and cell migration by regulating the expression of p-FAK in CRC cells. Thus, SphK1 may play a functional role in mediating the EMT process in CRC.

Visfatin triggers the in vitro migration of osteosarcoma cells via activation of NF-κB/IL-6 signals

Pulmonary metastasis is the major challenge for clinical treatment of osteosarcoma patients. Recent studies indicated that visfatin, a 52kDa adipocytokine, can trigger the cell motility of various cancers, while its role in the progression of osteosarcoma remains not clear. Our present study revealed that visfatin can significantly promote the in vitro migration and invasion of osteosarcoma MG-63 and HOS cells and up regulate the expression of matrix metalloproteinase-2 (MMP-2) and fibronectin (FN). Furthermore, visfatin treatment also increased the expression of IL-6 in both MG-63 and HOS cells via a time dependent manner, while anti-IL-6 antibody can significantly attenuate visfatin induced cell invasion and up regulation of MMP-2 and FN. It suggested that up regulation of IL-6 mediated visfatin induced in vitro motility of osteosarcoma cells. Visfatin treatment can increase the phosphorylation of both p65 and ERK1/2 in MG-63 and HOS cells, while only the inhibitor of NF-κB, BAY 11-7082, can abolish visfatin induced up regulation of IL-6. BAY 11-7082 also attenuated visfatin induced upregulation of MMP-2 and FN in MG-63 cells. Western blot analysis revealed that visfatin treatment can significantly increase the phosphorylation of IκBα and IKKβ in MG-63 cells. ACHP, the inhibitor of IKK-β, blocked visfatin induced expression of IL-6 mRNA in both MG-63 and HOS cells. Collectively, our data suggested that visfatin can increase the motility of osteosarcoma cells via up regulation of NF-κB/IL-6 signals. It indicated that visfatin might be a potential therapeutic target of osteosarcoma treatment.

Visfatin Triggers the Cell Motility of Non-Small Cell Lung Cancer via Up-Regulation of Matrix Metalloproteinases

High levels of visfatin are correlated with worse clinical prognosis of various cancers. Still, the effects and mechanisms of visfatin on progression of non-small cell lung cancer (NSCLC) remain unclear. This study revealed that plasma levels of visfatin in patients with NSCLC (585 ± 287 pg/ml) were significantly (p < 0.01) higher than those in healthy people (142 ± 61.1 pg/ml). The high level of plasma visfatin was found to be significantly (p < 0.05) correlated with TNM stage, lymph node metastasis and distant metastasis. Visfatin treatment can increase the migration and invasion of NSCLC cells via up-regulation of metalloproteinase-2 (MMP-2) and MMP-9. Both si-MMP-2 and si-MMP-9 attenuated visfatin-induced migration of NSCLC cells. The inhibitor of NF-κB, while not ERK1/2, p38-MAPK or PI3K/Akt, can significantly abolish visfatin-induced migration of A549 cells and up-regulation of MMP-2 and MMP-9. Furthermore, visfatin can increase the phosphorylation of IκBα and p65 and the transcription activities of NF-κB in NSCLC cells. ACHP, the inhibitor of IKK-β, blocked visfatin-induced activation of p65 and up-regulation of MMP-2 and MMP-9. Collectively, our data revealed that visfatin can trigger the in vitro migration and invasion of NSCLC cells via up-regulation of MMPs through activation of NF-κB.

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.

Visfatin is involved in promotion of colorectal carcinoma malignancy through an inducing EMT mechanism

Increasing evidences suggested visfatin, a newly discovered obesity-induced adipocytokine, is involved in promotion of cancer malignancy and correlated with worse clinical prognosis. While its effects and mechanisms on progression of colorectal cancer (CRC) remain unclear. Our clinical data show that visfatin protein is over expressed, positive associated with lymph node metastasis, high-grade tumor, and poor prognosis in 87 CRC patients. The levels of plasma visfatin are significantly upregulated in Stage IV colon cancer. Visfatin can significantly promote the in vitro migration and invasion of CRC cells via induction epithelial mesenchymal transition (EMT). It can increase the expression and nuclear translocation of Snail, a key transcription factor in regulating EMT. While silencing of Snail attenuates visfatin induced EMT. Further studies reveal visfatin can inhibit the association of Snail with GSK-3β and subsequently suppress ubiquitylation of Snail. In addition, visfatin can increase the expression and nuclear translocation of β-catenin, elevate its binding with Snail promoter, and then increase the transcription of Snail. While inhibitor of PI3K/Akt, LY294002, abolishes visfatin induced up regulation of Snail, Vimentin (Vim), β-catenin, and phosphorylated GSK-3β. In summary, our data suggest that increased expression of visfatin are associated with a more aggressive phenotype of CRC patients. It can trigger the EMT of CRC cells via Akt/GSK-3β/β-catenin signals.