GPR120 is not required for ω-3 PUFAs-induced cell growth inhibition and apoptosis in breast cancer cells

Akkermansia muciniphila supplementation improves glucose tolerance in intestinal Ffar4 knockout mice during the daily light to dark transition

IMPORTANCE

Alterations in the intestinal environment are associated with various diseases, and FFAR4 is abundantly enriched in the intestine, where it has been shown to have the ability to regulate intestinal hormone secretion and intestinal microbiota; here, we confirmed previous reports. Meanwhile, we found that intestinal FFAR4 regulates glucagon-like peptide 1 secretion by decreasing Akkermansia muciniphila abundance and show that such change is associated with the level of glucose utilization at ZT12 in mice. Intestinal FFAR4 deficiency leads to severely impaired glucose tolerance at the ZT12 moment in mice, and Akkermansia muciniphila supplementation ameliorates the abnormal glucose utilization at the ZT12 moment caused by FFAR4 deficiency, which is very similar to the dawn phenomenon in diabetic patients. Collectively, our data suggest that intestinal Ffar4 deteriorates glucose tolerance at the daily light to dark transition by affecting Akkermansia muciniphila.

Endogenous n-3 PUFAs Improve Non-Alcoholic Fatty Liver Disease through FFAR4-Mediated Gut-Liver Crosstalk

The gut-liver axis plays a key role in the development and progression of non-alcoholic fatty liver disease (NAFLD). Due to the complexity and incomplete understanding of the cross-talk between the gut and liver, effective therapeutic targets are largely unknown. Free fatty acid receptors (FFARs) may bridge the cross-talk between the gut and liver. FFAR4 has received considerable attention due to its important role in lipid metabolism. However, the role of FFAR4 in this cross talk in NAFLD remains unclear. In this study, mice with high endogenous n-3 PUFAs but FFAR4 deficiency were generated by crossbreeding Fat-1 and FFAR4 knockout mice. FFAR4 deficiency blocked the protective effects of high endogenous n-3 PUFAs on intestinal barrier dysfunction and hepatic steatosis. In addition, FFAR4 deficiency decreased gut microbiota diversity and enriched Rikenella, Anaerotruncus, and Enterococcus, and reduced Dubosiella, Ruminococcaceae UCG-010, Ruminococcaceae UCG-014, Coriobacteriaceae UCG-002, Faecalibaculum, Ruminococcaceae UCG-009, and Akkermansia. Notably, FFAR4 deficiency co-regulated pantothenic acid and CoA biosynthesis, β-alanine metabolism, and sphingolipid metabolism pathways in the gut and liver, potentially associated with the aggravation of NAFLD. Together, the beneficial effects of n-3 PUFAs on the gut and liver were mediated by FFAR4, providing insights on the role of FFAR4 in the treatment of NAFLD through the gut-liver axis.

Oncogenic signaling of the free-fatty acid receptors FFA1 and FFA4 in human breast carcinoma cells

Globally, breast cancer is the most frequent type of cancer in women, and most breast cancer-associated deaths are due to metastasis and recurrence of the disease. Dietary habits, specifically dietary fat intake is a crucial risk factor involved in breast cancer development and progression. Decades of research has revealed that free-fatty acids (FFA) modulate carcinogenic processes through fatty acid metabolism and lipid peroxidation. The ground-breaking discovery of free-fatty acid receptors, which are members of the G-protein coupled receptor (GPCR) superfamily, has led to the realization that FFA can also act via these receptors to modulate carcinogenic effects. The long-chain free-fatty acid receptors FFA1 (previously termed GPR40) and FFA4 (previously termed GPR120) are activated by mono- and polyunsaturated fatty acids including ω-3, 6, and 9 fatty acids. Initial enthusiasm towards the study of these receptors focused on their insulin secretagogue and sensitization effects, and the downstream associated metabolic regulation. However, recent studies have demonstrated that abnormal expression and/or aberrant FFA1/FFA4 signaling are evident in human breast carcinomas, suggesting that FFA receptors could be a promising target in the treatment of breast cancer. The current review discusses the diverse roles of FFA1 and FFA4 in the regulation of cell proliferation, migration, invasion, and chemotherapy resistance in human breast carcinoma cells and tissue.

GPR120 promotes metastasis but inhibits tumor growth in pancreatic ductal adenocarcinoma

OBJECTIVES

G-protein-coupled receptor 120 (GPR120) is a long-chain unsaturated fatty acid receptor, which regulates glucose metabolism and lipid. To date, there are disputes on the roles of GPR120 in the pathogenesis of cancer. Besides, little is known about its roles in the pathogenesis of pancreatic ductal adenocarcinoma (PDAC). This study was designed to investigate the roles of GPR120 in the pathogenesis of PDAC.

METHODS

Immunohistochemical staining (IHC) was used for detecting the level of GPR120, epithelial-mesenchymal transformation (EMT) markers, Ki-67 and CD31 in ninety-one PDAC patients. Western blot, CCK8, flow cytometry and transwell assays were performed to determine proliferation, apoptosis, and motility in vitro. Subcutaneous tumor model was established to validate the roles of GPR120 in vivo.

RESULTS

GPR120 was highly expressed in PDAC tissues, which was associated with free fatty acids (FFAs), lymph node metastasis (LNM), and poor prognosis. Moreover, GPR120 activation led to down-regulation of E-cadherin and up-regulation of Snail, Vimentin, N-cadherin, MMP2, MMP9, and CD31. Additionally, GPR120 decreased the expression of P-PI3K, P-AKT and CMYC and increased the level of P-JAK2, P-STAT3, Wnt5a, total β-catenin and β-catenin in nucleus.

CONCLUSIONS

GPR120 promoted proliferation inhibition and apoptosis of PDAC, and contributed to PDAC metastasis via inducing EMT and angiogenesis. GPR120 served as a double-edged sword in the pathogenesis of PDAC.

Nutraceuticals in the Mediterranean Diet: Potential Avenues for Breast Cancer Treatment

The traditional Mediterranean Diet constitutes a food model that refers to the dietary patterns of the population living in countries bordering the Mediterranean Sea in the early 1960s. A huge volume of literature data suggests that the Mediterranean-style diet provides several dietary compounds that have been reported to exert beneficial biological effects against a wide spectrum of chronic illnesses, such as cardiovascular and neurodegenerative diseases and cancer including breast carcinoma. Among bioactive nutrients identified as protective factors for breast cancer, natural polyphenols, retinoids, and polyunsaturated fatty acids (PUFAs) have been reported to possess antioxidant, anti-inflammatory, immunomodulatory and antitumoral properties. The multiple anticancer mechanisms involved include the modulation of molecular events and signaling pathways associated with cell survival, proliferation, differentiation, migration, angiogenesis, antioxidant enzymes and immune responses. This review summarizes the anticancer action of some polyphenols, like resveratrol and epigallocatechin 3-gallate, retinoids and omega-3 PUFAs by highlighting the important hallmarks of cancer in terms of (i) cell cycle growth arrest, (ii) apoptosis, (iii) inflammation and (iv) angiogenesis. The data collected from in vitro and in vivo studies strongly indicate that these natural compounds could be the prospective candidates for the future anticancer therapeutics in breast cancer disease.

Free Fatty Acids Promote the Development of Prostate Cancer by Upregulating Peroxisome Proliferator-Activated Receptor Gamma

Introduction

As one of the most common forms of cancer that threatens men's health, prostate cancer (PCa) is under a trend of increasing morbidity and mortality in most countries. More and more studies have pointed out that obesity is closely linked to the occurrence and development of PCa, although there are still many undiscovered molecular mechanisms between the two.

Methods

In the present study, we compare serum lipid levels in patients with PCa and normal individuals. PCa cells (PC3 and 22RV1) were cultured in vitro, the TC/TG/HDL/GLU assay kit was used to detect the glucose and lipid metabolism level of PCa cells, the flow cytometry technique was used to detect the proliferation ability of PCa cells, and the Transwell was used to detect the invasion and migration ability of PCa cells. Western blot/quantitative real-time PCR was used to detect peroxisome proliferator-activated receptor γ (PPARγ) and vimentin/vascular endothelial growth factor-A (VEGF-A) expression levels, and immunohistochemistry was used to observe tumor-associated gene expression levels in nude mice. All data were analysed using the Independent samples t-test or rank sum test.

Results

We found higher levels of FFA in the serum of patients with PCa. In vitro experiments have demonstrated that high levels of FFA can promote the proliferation, migration and invasion of two PCa cells (PC3 and 22RV1) and affect the energy metabolism of PCa cells. The upregulated PPARγ plays a key role in this process, and vimentin may be involved in this signaling pathway.

Conclusion

We infer that high levels of FFA may promote PCa development by upregulating PPARγ expression.

Increased GPR120 level is associated with gestational diabetes mellitus

G-protein coupled receptor 120 (GPR120 or FFAR4) functions as a receptor for free fatty acids and plays a critical role in lipid metabolism. Studies have shown a close relationship between GDM and lipid metabolism disorders, whether GPR120 participates in the metabolic regulation of GDM remains unclear. In this study, 29 women with GDM and 33 normal pregnant women were enrolled. Lipid profiles were determined by lipidomics, expression of GPR120 and FGF21 was measured in the white blood cells, and regulation of FGF21 by GPR120 was investigated in THP-1 cells as well as human peripheral blood monocytes. Lipidomics reveal altered lipid metabolism in patients with GDM. The expression of both GPR120 and FGF21 is significantly higher in the GDM than in the control at the 32nd and 37th weeks of pregnancy, but the differences disappear by the 2nd day post-delivery. Generally positive correlations are found between the total amount of lipids and expression levels of GPR120 and FGF21 in GDM patients. FGF21 expression is induced by GPR120 activation in THP-1 cells and WBCs. GPR120 may act as a metabolic regulator, through the induction of FGF21, to control lipid metabolism, and GDM patients may manifest a GPR120 insensitivity.

Fatty acid receptor GPR120 promotes breast cancer chemoresistance by upregulating ABC transporters expression and fatty acid synthesis

BACKGROUND

Chemoresistance is the major cause of neoadjuvant treatment failure in breast cancer patients. Despite recent progress, the mechanism underlying chemoresistance remains to be further defined.

METHODS

Expression of G protein-coupled receptor 120 (GPR120) was analyzed by immunohistochemistry in the biopsies of primary breast cancer who subsequently underwent preoperative neoadjuvant chemotherapy. In vitro and in vivo loss- and gain-of -function studies were performed to reveal the effects and related mechanism of GPR120 signaling pathway in the chemoresistance of breast cancer cells.

FINDINGS

We identified that GPR120, a receptor for long-chain fatty acids, was important for the acquisition of chemoresistance in breast cancer cells. We showed that GPR120 expression was positively associated with clinical response to neoadjuvant chemotherapy in patients. In breast cancer cells, GPR120 enhanced the de novo synthesis of fatty acids that served as GPR120 ligands to activate GPR120 signaling via a feedback mechanism. Upregulated GPR120 signaling rendered cells resistant to epirubicin-induced cell death by upregulating ABC transporters expression and thus decreasing the intracellular accumulation of epirubicin. Akt/NF-κB pathway was responsible for the GPR120-mediated expression of ABC transporters leading to modulation of the concentration of chemotherapeutic drugs in cells. The functional importance of GPR120 in chemoresistance was further validated using epirubicin-treated tumor xenografts, in which we showed that blockade of GPR120 signaling with AH7614 or GPR120-siRNA significantly compromised chemoresistance.

INTERPRETATION

Our results highlight that GPR120 might be a promising therapeutic target for breast cancer chemoresistance. FUND: National Natural Science Foundation of China, Ministry of Science and Technology of China, Program of Science and Technology Commission of Shanghai Municipality.