The Impact of Adipose Tissue-Derived miRNAs in Metabolic Syndrome, Obesity, and Cancer.

Obesity is a multifactorial and complex condition that is characterized by abnormal and excessive white adipose tissue accumulation, which can lead to the development of metabolic diseases, such as type 2 diabetes mellitus, nonalcoholic fatty liver disease, cardiovascular diseases, and several types of cancer. Obesity is characterized by excessive adipose tissue accumulation and associated with alterations in immunity, displaying a chronic low-grade inflammation profile. Adipose tissue is a dynamic and complex endocrine organ composed not only by adipocytes, but several immunological cells, which can secrete hormones, cytokines and many other factors capable of regulating metabolic homeostasis and several critical biological pathways. Remarkably, adipose tissue is a major source of circulating microRNAs (miRNAs), recently described as a novel form of adipokines. Several adipose tissue-derived miRNAs are deeply associated with adipocytes differentiation and have been identified with an essential role in obesity-associated inflammation, insulin resistance, and tumor microenvironment. During obesity, adipose tissue can completely change the profile of the secreted miRNAs, influencing circulating miRNAs and impacting the development of different pathological conditions, such as obesity, metabolic syndrome, and cancer. In this review, we discuss how miRNAs can act as epigenetic regulators affecting adipogenesis, adipocyte differentiation, lipid metabolism, browning of the white adipose tissue, glucose homeostasis, and insulin resistance, impacting deeply obesity and metabolic diseases. Moreover, we characterize how miRNAs can often act as oncogenic and tumor suppressor molecules, significantly modulating cancer establishment and progression. Furthermore, we highlight in this manuscript how adipose tissue-derived miRNAs can function as important new therapeutic targets.

Obesity and Breast Cancer: The Role of Crown-Like Structures in Breast Adipose Tissue in Tumor Progression, Prognosis, and Therapy.

Obesity is associated with increased risk and aggressiveness of many types of cancer. Women with obesity and breast cancer are more likely to be diagnosed with larger and higher-grade tumors and have higher incidence of metastases than lean individuals. Increasing evidence indicates that obesity includes systemic, chronic low-grade inflammation, and that adipose tissue can act as an important endocrine site, secreting a variety of substances that may regulate inflammation, immune response, and cancer predisposition. Obesity-associated inflammation appears to be initially mediated by macrophage infiltration into adipose tissue. Macrophages can surround damaged or necrotic adipocytes, forming "crown-like" structures (CLS). CLS are increased in breast adipose tissue from breast cancer patients and are more abundant in patients with obesity conditions. Moreover, the CLS index-ratio from individuals with obesity seems to influence breast cancer recurrence rates and survival. In this review, we discuss the most recent cellular and molecular mechanisms involved in CLS establishment in the white adipose tissue of women with obesity and their implications for breast cancer biology. We also explain how CLS influence the tumor microenvironment and affect breast cancer behavior. Targeting breast adipose tissue CLS can be a crucial therapeutic tool in cancer treatment, especially in patients with obesity.

The Impact of the Adipose Organ Plasticity on Inflammation and Cancer Progression.

Obesity is characterized by chronic and low-grade systemic inflammation, an increase of adipose tissue, hypertrophy, and hyperplasia of adipocytes. Adipose tissues can be classified into white, brown, beige and pink adipose tissues, which display different regulatory, morphological and functional characteristics of their adipocyte and immune cells. Brown and white adipocytes can play a key role not only in the control of energy homeostasis, or through the balance between energy storage and expenditure, but also by the modulation of immune and inflammatory responses. Therefore, brown and white adipocytes can orchestrate important immunological crosstalk that may deeply impact the tumor microenvironment and be crucial for cancer establishment and progression. Recent works have indicated that white adipose tissues can undergo a process called browning, in which an inducible brown adipocyte develops. In this review, we depict the mechanisms involved in the differential role of brown, white and pink adipocytes, highlighting their structural, morphological, regulatory and functional characteristics and correlation with cancer predisposition, establishment, and progression. We also discuss the impact of the increased adiposity in the inflammatory and immunological modulation. Moreover, we focused on the plasticity of adipocytes, describing the molecules produced and secreted by those cells, the modulation of the signaling pathways involved in the browning phenomena of white adipose tissue and its impact on inflammation and cancer.

Molecular evaluation of anti-inflammatory activity of phenolic lipid extracted from cashew nut shell liquid (CNSL).

BACKGROUND: Anacardium occidentale L phenolic lipid (LDT11) is used in traditional medicine as anti-inflammatory, astringent, antidiarrheal, anti-asthmatic and depurative. Phenolic derivatives, such as anacardic acid, extracted from cashew nut shell liquid (CNSL) have demonstrated biological and pharmacological properties, and its profile makes it a candidate for the development of new anti-inflammatory agents. The objective of the present study was to evaluate the anti-inflammatory profile of a derivative, synthesized from LDT11, on an in vitro cellular model. METHODS: Organic synthesis of the phenolic derivative of CNSL that results in the hemi-synthetic compound LDT11. The cytotoxicity of the planned compound, LDT11, was analyzed in murine macrophages cell line, RAW264.7. The cells were previously treated with LDT11, and then, the inflammation was stimulated with lipopolysaccharide (LPS), in intervals of 6 h and 24 h. The analysis of the gene expression of inflammatory markers (TNFα, iNOS, COX-2, NF-κB, IL-1ß and IL-6), nitric oxide (NO) dosage, and cytokine IL-6 were realized. RESULTS: The results showed that the phenolic derivative, LDT11, influenced the modulatory gene expression. The relative gene transcripts quantification demonstrated that the LDT11 disclosed an immunoprotective effect against inflammation by decreasing genes expression when compared with cells stimulated with LPS in the control group. The NO and IL-6 dosages confirmed the results found in gene expression. DISCUSSION: The present study evaluated the immunoprotective effect of LDT11. In addition to a significant reduction in the expression of inflammatory genes, LDT11 also had a faster and superior anti-inflammatory action than the commercial products, and its response was already evident in the test carried out six hours after the treatment of the cells. CONCLUSION: This study demonstrated LDT11 is potentially valuable as a rapid immunoprotective anti-inflammatory agent. Treatment with LDT11 decreased the gene expression of inflammatory markers, and the NO, and IL-6 production. When compared to commercial drugs, LDT11 showed a superior anti-inflammatory action.