Role of Leptin and Adiponectin in Endometrial Cancer

Effects of exercise training on glucose metabolism indicators and inflammatory markers in obese children and adolescents: A meta-analysis

BACKGROUND

Obesity in children and adolescents is a serious problem, and the efficacy of exercise therapy for these patients is controversial.

AIM

To assess the efficacy of exercise training on overweight and obese children based on glucose metabolism indicators and inflammatory markers.

METHODS

The PubMed, Web of Science, and Embase databases were searched for ran-domized controlled trials related to exercise training and obese children until October 2023. The meta-analysis was conducted using RevMan 5.3 software to evaluate the efficacy of exercise therapy on glucose metabolism indicators and inflammatory markers in obese children.

RESULTS

In total, 1010 patients from 28 studies were included. Exercise therapy reduced the levels of fasting blood glucose (FBG) [standardized mean difference (SMD): -0.78; 95% confidence interval (CI): -1.24 to -0.32, P = 0.0008], fasting insulin (FINS) (SMD: -1.55; 95%CI: -2.12 to -0.98, P < 0.00001), homeostatic model assessment for insulin resistance (HOMA-IR) (SMD: -1.58; 95%CI: -2.20 to -0.97, P < 0.00001), interleukin-6 (IL-6) (SMD: -1.31; 95%CI: -2.07 to -0.55, P = 0.0007), C-reactive protein (CRP) (SMD: -0.64; 95%CI: -1.21 to -0.08, P = 0.03), and leptin (SMD: -3.43; 95%CI: -5.82 to -1.05, P = 0.005) in overweight and obese children. Exercise training increased adiponectin levels (SMD: 1.24; 95%CI: 0.30 to 2.18, P = 0.01) but did not improve tumor necrosis factor-alpha (TNF-α) levels (SMD: -0.80; 95%CI: -1.77 to 0.18, P = 0.11).

CONCLUSION

In summary, exercise therapy improves glucose metabolism by reducing levels of FBG, FINS, HOMA-IR, as well as improves inflammatory status by reducing levels of IL-6, CRP, leptin, and increasing levels of adiponectin in overweight and obese children. There was no statistically significant effect between exercise training and levels of TNF-α. Additional long-term trials should be conducted to explore this therapeutic perspective and confirm these results.

Weight-centric prevention of cancer

Background

The link between excess adiposity and carcinogenesis has been well established for multiple malignancies, and cancer is one of the main contributors to obesity-related mortality. The potential role of different weight-loss interventions on cancer risk modification has been assessed, however, its clinical implications remain to be determined. In this clinical review, we present the data assessing the effect of weight loss interventions on cancer risk.

Methods

In this clinical review, we conducted a comprehensive search of relevant literature using MEDLINE, Embase, Web of Science, and Google Scholar databases for relevant studies from inception to January 20, 2024. In this clinical review, we present systematic reviews and meta-analysis, randomized clinical trials, and prospective and retrospective observational studies that address the effect of different treatment modalities for obesity in cancer risk. In addition, we incorporate the opinions from experts in the field of obesity medicine and oncology regarding the potential of weight loss as a preventative intervention for cancer.

Results

Intentional weight loss achieved through different modalities has been associated with a reduced cancer incidence. To date, the effect of weight loss on the postmenopausal women population has been more widely studied, with multiple reports indicating a protective effect of weight loss on hormone-dependent malignancies. The effect of bariatric interventions as a protective intervention for cancer has been studied extensively, showing a significant reduction in cancer incidence and mortality, however, data for the effect of bariatric surgery on certain specific types of cancer is conflicting or limited.

Conclusion

Medical nutrition therapy, exercise, antiobesity medication, and bariatric interventions, might lead to a reduction in cancer risk through weight loss-dependent and independent factors. Further evidence is needed to better determine which population might benefit the most, and the amount of weight loss required to provide a clinically significant preventative effect.

The solution structure of human leptin reveals a conformational plasticity important for receptor recognition

Leptin is a multi-potency cytokine that regulates various physiological functions, including weight control and energy homeostasis. Signaling of leptin is also important in many aging-related diseases. Leptin is required for the noncovalent crosslinking of different extracellular domains of leptin receptors, which is critical for receptor activation and downstream signaling. Nevertheless, the structure of intact apo-form leptin and the structural transition leptin undergoes upon receptor binding are not fully understood yet. Here, we determined the monomeric structure of wild-type human leptin by solution-state nuclear magnetic resonance spectroscopy. Leptin contains an intrinsically disordered region (IDR) in the internal A-B loop and the flexible helix E in the C-D loop, both of which undergo substantial local structural changes when leptin binds to its receptor. Our findings provide further insights into the molecular mechanisms of leptin signaling.

AdipoRon and ADP355, adiponectin receptor agonists, in Metabolic-associated Fatty Liver Disease (MAFLD) and Nonalcoholic Steatohepatitis (NASH): A systematic review

Adiponectin replacement therapy holds the potential to benefit numerous human diseases, and ongoing research applies particular interest in how adiponectin acts against Metabolic-associated Fatty Liver Disease (MAFLD) and Nonalcoholic Steatohepatitis (NASH). However, the pharmacological limitations of the intact protein have prompted a focus on alternative options, specifically peptidic and small molecule agonists targeting the adiponectin receptor. AdipoRon is an extensively researched non-peptidic drug candidate in adiponectin replacement therapy. In turn, ADP355 is an adiponectin-based active short peptide. They have garnered significant attention due to their potential as substitutes for adiponectin. Researchers have studied AdipoRon's and ADP355's efficacy and therapeutic applications in various disease conditions. However, the effects of AdipoRon and ADP355 against NAFLD and NASH models advanced more, and no systematic review explored this area before. This systematic review was conceived to address the deficiency mentioned above and consider the lack of clinical evidence. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were utilized. To assess the risk of bias in systematic review, The Joanna Briggs Institute (JBI) Critical Appraisal Checklist was employed. Results from pre-clinical evidence show that AdipoRon and ADP355 represent promising effects in NAFLD and NASH-related models, including reducing hepatic steatosis, modulating inflammation, improving insulin sensitivity, enhancing mitochondrial function, and protecting against liver fibrosis. While AdipoRon and ADP355 exhibit promise in pre-clinical studies and experimental models, additional clinical trials are necessary to assess their effectiveness, safety, and potential translational therapeutic potential uses in NAFLD and NASH human cases.

Beyond Body Size: Adiponectin as a Key Player in Obesity-Driven Cancers

Obesity, a complex and multifactorial disease influenced by genetic, environmental, and psychological factors, has reached epidemic proportions globally, posing a significant health challenge. In addition to its established association with cardiovascular disease and type II diabetes, obesity has been implicated as a risk factor for various cancers. However, the precise biological mechanisms linking obesity and cancer remain largely understood. Adipose tissue, an active endocrine organ, produces numerous hormones and bioactive molecules known as adipokines, which play a crucial role in metabolism, immune responses, and systemic inflammation. Notably, adiponectin (APN), the principal adipocyte secretory protein, exhibits reduced expression levels in obesity. In this scoping review, we explore and discuss the role of APN in influencing cancer in common malignancies, including lung, breast, colorectal, prostate, gastric, and endometrial cancers. Our review aims to emphasize the critical significance of investigating this field, as it holds great potential for the development of innovative treatment strategies that specifically target obesity-related malignancies. Furthermore, the implementation of more rigorous and comprehensive prevention and treatment policies for obesity is imperative in order to effectively mitigate the risk of associated diseases, such as cancer.

Update on Adipose Tissue and Cancer

Adipose tissue is the largest endocrine organ and an accepted contributor to overall energy homeostasis. There is strong evidence linking increased adiposity to the development of 13 types of cancer. With increased adiposity comes metabolic dysfunction and insulin resistance, and increased systemic insulin and glucose support the growth of many cancers, including those of the colon and endometrium. There is also an important direct crosstalk between adipose tissue and various organs. For instance, the healthy development and function of the mammary gland, as well as the development, growth, and progression of breast cancer, are heavily impacted by the breast adipose tissue in which breast epithelial cells are embedded. Cells of the adipose tissue are responsive to external stimuli, including overfeeding, leading to remodeling and important changes in the secretion of factors known to drive the development and growth of cancers. Loss of factors like adiponectin and increased production of leptin, endotrophin, steroid hormones, and inflammatory mediators have been determined to be important mediators of the obesity-cancer link. Obesity is also associated with a structural remodeling of the adipose tissue, including increased localized fibrosis and disrupted angiogenesis that contribute to the development and progression of cancers. Furthermore, tumor cells feed off the adipose tissue, where increased lipolysis within adipocytes leads to the release of fatty acids and stromal cell aerobic glycolysis leading to the increased production of lactate. Both have been hypothesized to support the higher energetic demands of cancer cells. Here, we aim to provide an update on the state of the literature revolving around the role of the adipose tissue in cancer initiation and progression.

Recent progress in leptin signaling from a structural perspective and its implications for diseases

As a multi-potency cytokine, leptin not only plays a crucial role in controlling weight and energy homeostasis but also participates in the metabolic balance in the human body. Leptin is a small helical protein with a molecular weight of 16 kDa. It can interact with multiple subtypes of its receptors to initiate intracellular signal transduction and exerts physiological effects. Disturbances in leptin signaling may lead to obesity and a variety of metabolic diseases. Leptin was also found to be a critical factor in many diseases of the elderly. In this review, we focus on recent advances in the structural and molecular mechanisms of leptin signaling through its receptors with the aim of a deeper understanding of leptin-related diseases.

Positive Regulation of Acetate in Adipocyte Differentiation and Lipid Deposition in Obese Mice

Acetate is associated with adipocyte differentiation and lipid deposition. To further develop this scientific point, obese mice on a high-fat diet were given an intragastric administration of acetate for 8 weeks and mouse adipose mesenchymal stem cells (mAMSCs) were treated with acetate for 24 h. The results showed that the body weight, food intake, Lee's index, adipose tissue coefficient, liver index, blood lipid levels, insulin resistance, pro-inflammatory factors levels and fatty lesions in liver and adipose tissue in obese mice treated with acetate increased markedly, while anti-inflammatory factors levels and liver function decreased significantly (p < 0.05). The mRNA expression levels of PPAR-γ, C/EBP-α, SREBP, AFABP, FAS, ACC-1, SCD-1, LPL, LEPR, GPR41 and GPR43 genes in adipose tissue and mAMSCs were significantly increased, while the mRNA expression levels of HSL, CPT-1, CPT-2, AMPK, AdipoR1 and AdipoR2 genes were significantly reduced (p < 0.05). Except for AMPK-α signaling pathway proteins, the phosphorylation levels of p38 MAPK, ERK1/2, JNK and mTOR were significantly increased (p < 0.05) and these changes were dose-dependent. The findings indicated that acetate played a positive role in regulating adipocyte differentiation and lipid deposition by activating MAPKs and mTOR signaling pathways (the expression up-regulation of genes such as PPAR-γ, C/EBP-α and SREBP-1, etc.) and inhibiting the AMPK signaling pathway (the expression down-regulation of genes such as HSL, CPT-1 and AMPK-α, etc.).

Orlistat exerts anti-obesity and anti-tumorigenic effects in a transgenic mouse model of endometrial cancer

Introduction

Among all cancers, endometrial cancer is most strongly associated with obesity, with more than 65% of endometrial cancers attributable to obesity and being overweight. Fatty acid synthase (FAS), a key lipogenic enzyme, is expressed in endometrial cancer tumors and is associated with a worse prognosis for this disease. Orlistat, an FAS inhibitor, is an FDA-approved weight loss medication that has demonstrated anti-tumor activity in a variety of preclinical cancer models.

Methods

In this study, the Lkb1fl/flp53fl/fl mouse model of endometroid endometrial cancer was exposed to three diet interventions, including a high fat diet (obese), a low fat diet (lean) and switch from a high fat to a low fat diet, and then exposed to orlistat or placebo.

Results

The mice fed a high-fat diet had significantly increased body weight and tumor weight compared to mice fed a low-fat diet. Switching from a high-fat diet to a low fat diet led to a reduction in mouse weight and suppressed tumor growth, as compared to both the high fat diet and low fat diet groups. Orlistat effectively decreased body weight in obese mice and inhibited tumor growth in obese, lean, and the high fat diet switch to low fat diet mouse groups through induction of apoptosis. Orlistat also showed anti-proliferative activity in nine of 11 primary cultures of human endometrial cancer.

Discussion

Our findings provide strong evidence that dietary intervention and orlistat have anti-tumor activity in vivo and supports further investigation of orlistat in combination with dietary interventions for the prevention and treatment of endometrial cancer.

Etiological relationship between lipid metabolism and endometrial carcinoma

Endometrial carcinoma (EC) has become one of the most common gynecological malignant neoplasms in developed countries worldwide. Studies have shown that this may be closely related to the abnormal metabolism of blood lipids, which was the most significant metabolic change in the human body in this cancer. In this review, we focus on the correlation between lipid metabolism and EC and discuss the evidence that abnormal lipid metabolism promotes an increase in EC growth and metabolism, as well as the regulatory mechanism and related signaling pathways involved in this relationship. In addition, we also discussed the research progress of targeted therapies and drug treatments for EC that act on lipid metabolism, and statins are expected to become adjuvant drugs for EC in the future. This review will provide a systematic view for a better understanding of the etiological relationship between lipid metabolism and EC and further open up new therapeutic possibilities and effective treatments for EC by targeting lipid metabolism.

The Role of Selected Adipocytokines in Ovarian Cancer and Endometrial Cancer

Due to their multidirectional influence, adipocytokines are currently the subject of numerous intensive studies. Significant impact applies to many processes, both physiological and pathological. Moreover, the role of adipocytokines in carcinogenesis seems particularly interesting and not fully understood. For this reason, ongoing research focuses on the role of these compounds in the network of interactions in the tumor microenvironment. Particular attention should be drawn to cancers that remain challenging for modern gynecological oncology-ovarian and endometrial cancer. This paper presents the role of selected adipocytokines, including leptin, adiponectin, visfatin, resistin, apelin, chemerin, omentin and vaspin in cancer, with a particular focus on ovarian and endometrial cancer, and their potential clinical relevance.

Malic Enzyme 1 (ME1) Promotes Adiposity and Hepatic Steatosis and Induces Circulating Insulin and Leptin in Obese Female Mice

Malic Enzyme 1 (ME1) supports lipogenesis, cholesterol synthesis, and cellular redox potential by catalyzing the decarboxylation of L-malate to pyruvate, and the concomitant reduction of NADP to NADPH. We examined the contribution of ME1 to the development of obesity by provision of an obesogenic diet to C57BL/6 wild type (WT) and MOD-1 (lack ME1 protein) female mice. Adiposity, serum hormone levels, and adipose, mammary gland, liver, and small intestine gene expression patterns were compared between experimental groups after 10 weeks on a diet. Relative to WT female mice, MOD-1 female mice exhibited lower body weights and less adiposity; decreased concentrations of insulin, leptin, and estrogen; higher concentrations of adiponectin and progesterone; smaller-sized mammary gland adipocytes; and reduced hepatosteatosis. MOD-1 mice had diminished expression of Lep gene in abdominal fat; Lep, Pparg, Klf9, and Acaca genes in mammary glands; Pparg and Cdkn1a genes in liver; and Tlr9 and Ffar3 genes in the small intestine. By contrast, liver expression of Cdkn2a and Lepr genes was augmented in MOD-1, relative to WT mice. Results document an integrative role for ME1 in development of female obesity, suggest novel linkages with specific pathways/genes, and further support the therapeutic targeting of ME1 for obesity, diabetes, and fatty liver disease.

Potential biomarkers in endometrial cancer: a narrative review

CONTEXT

Every year, approximately 0.4 million women suffer from endometrial cancer (EC) worldwide and it has become the most common gynecological malignancy. Almost 66% of EC cases are diagnosed at an early stage and can be cured by performing surgery while those at an advanced stage turns out to be fatal. Biomarkers of endometrial cancer would be very valuable for screening of women who are at high risk and in detecting the chance of recurrence of disease.

OBJECTIVE

The current article has reviewed studies published on expression of biomarkers and susceptibility to EC.

METHODS

Google Scholar and PubMed were used as searching platforms and we have majorly considered the literature from last 10 years.

RESULTS

Potential biomarkers of EC identified from various studies were summarised.

The Adipocyte-Macrophage Relationship in Cancer: A Potential Target for Antioxidant Therapy

Obesity has emerged as a major public health concern with a staggering 39% worldwide prevalence as of 2021. Given the magnitude of the problem and considering its association with chronic low-grade systemic inflammation, it does not come as a surprise that obesity is now considered one of the major risk factors for the development of several chronic diseases, such as diabetes, cardiovascular problems, and cancer. Adipose tissue dysfunction in obesity has taken center stage in understanding how changes in its components, particularly adipocytes and macrophages, participate in such processes. In this review, we will initially focus on how changes in adipose tissue upon excess fat accumulation generate endocrine signals that promote cancer development. Moreover, the tumor microenvironment or stroma, which is also critical in cancer development, contains macrophages and adipocytes, which, in reciprocal paracrine communication with cancer cells, generate relevant signals. We will discuss how paracrine signaling in the tumor microenvironment between cancer cells, macrophages, and adipocytes favors cancer development and progression. Finally, as reactive oxygen species participate in many of these signaling pathways, we will summarize the information available on how antioxidants can limit the effects of endocrine and paracrine signaling due to dysfunctional adipose tissue components in obesity.

Fertility-Sparing Strategies for Early-Stage Endometrial Cancer: Stepping towards Precision Medicine Based on the Molecular Fingerprint

Endometrial cancer represents the fifth most common cancer in women, and the most common gynecological malignancy in developed countries [...].