Characterizing the differential physiological effects of adipocytokines visfatin and resistin in liver cancer cells

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.

Microenvironmental Factors Modulating Tumor Lipid Metabolism: Paving the Way to Better Antitumoral Therapy

Metabolic reprogramming is one of the emerging hallmarks of cancer and is driven by both the oncogenic mutations and challenging microenvironment. To satisfy the demands of energy and biomass for rapid proliferation, the metabolism of various nutrients in tumor cells undergoes important changes, among which the aberrant lipid metabolism has gained increasing attention in facilitating tumor development and metastasis in the past few years. Obstacles emerged in the aspect of application of targeting lipid metabolism for tumor therapy, due to lacking of comprehensive understanding on its regulating mechanism. Tumor cells closely interact with stromal niche, which highly contributes to metabolic rewiring of critical nutrients in cancer cells. This fact makes the impact of microenvironment on tumor lipid metabolism a topic of renewed interest. Abundant evidence has shown that many factors existing in the tumor microenvironment can rewire multiple signaling pathways and proteins involved in lipid metabolic pathways of cancer cells. Hence in this review, we summarized the recent progress on the understanding of microenvironmental factors regulating tumor lipid metabolism, and discuss the potential of modulating lipid metabolism as an anticancer approach.

Resistin Expression in Epithelial Ovarian Cancer promotes the Proliferation and Migration of Ovarian Cancer Cells to Worsen Prognosis

Background: Epithelial ovarian cancer (EOC) is the most common gynecological cancer in women. Resistin, an inflammatory adipocytokine, is associated with obesity, insulin resistance, and various cancer types.

Materials and Methods: We investigated resistin expression in tissues and its association with the clinicopathological characteristics and prognosis of patients with EOC. The SKOV3 and CAOV3 cell lines were treated with exogenous resistin and rapamycin (resistin inhibitor), and the expression of mTOR in SKOV3 and CAOV3 cells was measured. Cell proliferation was measured using the CCK-8 assay. Western blotting analysis was performed to examine the phosphorylation of P70S6K and mTOR. Wound healing and Transwell analyses were conducted to examine the effect of resistin on the migration of SKOV3 and CAOV3 cells.

Results: High resistin expression was positively correlated with the pathological grade (P = 0.017) and lymph node metastasis (P = 0.045). However, resistin expression was not correlated with age, FIGO stage, or residual tumor after initial laparotomy (P > 0.05). Cox multivariate analysis showed that resistin expression was an independent factor for determining disease-free survival, whereas lymph node metastasis, resistin expression, and age (≥55 years) were independent factors affecting overall survival. Exogenous resistin induced ovarian cancer cell proliferation, whereas rapamycin had the opposite effect. Resistin promoted the proliferation of ovarian cancer cells via the mTOR signaling pathway and was associated with phosphorylating P70S6K. Furthermore, resistin promoted the migration of ovarian cancer cells.

Conclusions: Resistin may promote the occurrence of ovarian cancer and is related to the prognosis of patients. This protein may also affect the proliferation of EOC cells through the mTOR signaling pathway. Therefore, resistin shows potential as a molecular therapeutic target in ovarian cancer.

Surgery for Obesity and Weight-Related Diseases Changes the Inflammatory Profile in Women with Severe Obesity: a Randomized Controlled Clinical Trial

INTRODUCTION/PURPOSE

Obesity increases significantly every year worldwide. Since 1980, the prevalence of individuals with obesity has practically doubled. Obesity plays an important role in the pathophysiology of diseases that arise from a complex interaction of nutritional, genetic, and metabolic factors, characterizing a chronic inflammatory state. This study aimed to verify the systemic inflammatory response through the analysis of IGF-1, IL-23, and resistin levels and the lipid profile in severely obese women undergoing surgery for obesity and weight-related diseases.

MATERIALS AND METHODS

This randomized controlled clinical trial includes female patients clinically diagnosed with severe obesity with an indication for bariatric surgery.

RESULTS

In the initial evaluation, no significant difference was observed between the control (CG) and bariatric surgery (BSG) groups. The weight, BMI, systolic and diastolic blood pressures, total cholesterol, LDL, HDL, total non-HDL cholesterol, and glucose in BSG patients showed a significant change after surgery. Pre- and post-surgery levels of resistin, IGF-1, and IL-23 showed a significant difference in the BSG group, but only IL-23 was changed after 6 months in the CG.

CONCLUSION

The results of this study confirmed that weight loss induced by surgery for obesity and weight-related diseases improved the lipid profile and reduced the chronic inflammatory status in women with severe obesity.

Inhibition of PI3K/Akt and ERK signaling decreases visfatin-induced invasion in liver cancer cells

OBJECTIVES

Visfatin is found in adipose tissue and is referred to as nicotinamide phosphoribosyltransferase (Nampt). Visfatin has anti-apoptotic, proliferative, and metastatic properties and may mediate its effects via ERK and PI3K/Akt signaling. Studies have yet to determine whether inhibition of kinase signaling will suppress visfatin-induced liver cancer. The purpose of this study was to determine which signaling pathways visfatin may promote liver cancer progression.

METHODS

HepG2 and SNU-449 liver cancer cells were exposed to visfatin with or without ERK or PI3K/Akt inhibitor, or both inhibitors combined. These processes that were assessed: proliferation, reactive oxygen species (ROS), lipogenesis, invasion, and matrix metalloproteinase (MMP).

RESULTS

Inhibition of PI3K/Akt and combination of inhibitors suppressed visfatin-induced viability. ERK inhibition in HepG2 cells decreased visfatin-induced proliferation. ERK inhibitor alone or in combination with PI3K inhibitors effectively suppressed MMP-9 secretion and invasion in liver cancer cells. PI3K and ERK inhibition and PI3K inhibition alone blocked visfatin's ROS production in SNU-449 cells. These results corresponded with a decrease in phosphorylated Akt and ERK, β-catenin, and fatty acid synthase.

CONCLUSIONS

Akt and ERK inhibition differentially regulated physiological changes in liver cancer cells. Inhibition of Akt and ERK signaling pathways suppressed visfatin-induced invasion, viability, MMP-9 activation, and ROS production.

Tumor Metabolic Reprogramming by Adipokines as a Critical Driver of Obesity-Associated Cancer Progression

Adiposity is associated with an increased risk of various types of carcinoma. One of the plausible mechanisms underlying the tumor-promoting role of obesity is an aberrant secretion of adipokines, a group of hormones secreted from adipose tissue, which have exhibited both oncogenic and tumor-suppressing properties in an adipokine type- and context-dependent manner. Increasing evidence has indicated that these adipose tissue-derived hormones differentially modulate cancer cell-specific metabolism. Some adipokines, such as leptin, resistin, and visfatin, which are overproduced in obesity and widely implicated in different stages of cancer, promote cellular glucose and lipid metabolism. Conversely, adiponectin, an adipokine possessing potent anti-tumor activities, is linked to a more favorable metabolic phenotype. Adipokines may also play a pivotal role under the reciprocal regulation of metabolic rewiring of cancer cells in tumor microenvironment. Given the fact that metabolic reprogramming is one of the major hallmarks of cancer, understanding the modulatory effects of adipokines on alterations in cancer cell metabolism would provide insight into the crosstalk between obesity, adipokines, and tumorigenesis. In this review, we summarize recent insights into putative roles of adipokines as mediators of cellular metabolic rewiring in obesity-associated tumors, which plays a crucial role in determining the fate of tumor cells.

Resistin: An inflammatory cytokine with multi-faceted roles in cancer

Systemic and organ-confined inflammation has been associated with cancer development and progression. Resistin, initially described as an adipocyte-derived cytokine in mice, is mostly expressed by the macrophages in humans. It has potent pro-inflammatory properties, and its elevated serum levels are detected in cancer patients. Aberrant expression of resistin receptors is also reported in several malignancies and associated with aggressive clinicopathological features. Several lines of evidence demonstrate that resistin, acting through its different receptors, promotes tumor growth, metastasis, and chemoresistance by influencing a variety of cellular phenotypes as well as by modulating the tumor microenvironment. Racially disparate expression of resistin has also attracted much interest, considering prevalent cancer health disparities. This review discusses the aberrant expression of resistin and its receptors, its diverse downstream signaling and impact on tumor growth, metastasis, angiogenesis, and therapy resistance to support its clinical exploitation in biomarker and therapeutic development.