scholarly journals Peroxisome Proliferator-Activated Receptor γ and PGC-1α in Cancer: Dual Actions as Tumor Promoter and Suppressor

PPAR Research ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Seong-Hoon Yun ◽  
Sang-Heum Han ◽  
Joo-In Park

Peroxisome proliferator-activated receptor γ (PPARγ) is part of a nuclear receptor superfamily that regulates gene expression involved in cell differentiation, proliferation, immune/inflammation response, and lipid metabolism. PPARγ coactivator-1α (PGC-1α), initially identified as a PPARγ-interacting protein, is an important regulator of diverse metabolic pathways, such as oxidative metabolism and energy homeostasis. The role of PGC-1α in diabetes, neurodegeneration, and cardiovascular disease is particularly well known. PGC-1α is also now known to play important roles in cancer, independent of the role of PPARγ in cancer. Though many researchers have studied the expression and clinical implications of PPARγ and PGC-1α in cancer, there are still many controversies about the role of PPARγ and PGC-1α in cancer. This review examines and summarizes some recent data on the role and action mechanisms of PPARγ and PGC-1α in cancer, respectively, particularly the recent progress in understanding the role of PPARγ in several cancers since our review was published in 2012.

2020 ◽  
Vol 21 (6) ◽  
pp. 2061 ◽  
Author(s):  
Yaping Wang ◽  
Takero Nakajima ◽  
Frank J. Gonzalez ◽  
Naoki Tanaka

Peroxisome proliferator-activated receptor (PPAR) α, β/δ, and γ modulate lipid homeostasis. PPARα regulates lipid metabolism in the liver, the organ that largely controls whole-body nutrient/energy homeostasis, and its abnormalities may lead to hepatic steatosis, steatohepatitis, steatofibrosis, and liver cancer. PPARβ/δ promotes fatty acid β-oxidation largely in extrahepatic organs, and PPARγ stores triacylglycerol in adipocytes. Investigations using liver-specific PPAR-disrupted mice have revealed major but distinct contributions of the three PPARs in the liver. This review summarizes the findings of liver-specific PPAR-null mice and discusses the role of PPARs in the liver.


2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Kousei Ohshima ◽  
Masaki Mogi ◽  
Masatsugu Horiuchi

Vascular inflammation plays a crucial role in atherosclerosis, and its regulation is important to prevent cerebrovascular and coronary artery disease. The inflammatory process in atherogenesis involves a variety of immune cells including monocytes/macrophages, lymphocytes, dendritic cells, and neutrophils, which all express peroxisome proliferator-activated receptor-γ(PPAR-γ). PPAR-γis a nuclear receptor and transcription factor in the steroid superfamily and is known to be a key regulator of adipocyte differentiation. Increasing evidence from mainly experimental studies has demonstrated that PPAR-γactivation by endogenous and synthetic ligands is involved in lipid metabolism and anti-inflammatory activity. In addition, recent clinical studies have shown a beneficial effect of thiazolidinediones, synthetic PPAR-γligands, on cardiovascular disease beyond glycemic control. These results suggest that PPAR-γactivation is an important regulator in vascular inflammation and is expected to be a therapeutic target in the treatment of atherosclerotic complications. This paper reviews the recent findings of PPAR-γinvolvement in vascular inflammation and the therapeutic potential of regulating the immune system in atherosclerosis.


PPAR Research ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-20 ◽  
Author(s):  
Maryam Rakhshandehroo ◽  
Bianca Knoch ◽  
Michael Müller ◽  
Sander Kersten

The peroxisome proliferator-activated receptor alpha (PPARα) is a ligand-activated transcription factor involved in the regulation of a variety of processes, ranging from inflammation and immunity to nutrient metabolism and energy homeostasis. PPARαserves as a molecular target for hypolipidemic fibrates drugs which bind the receptor with high affinity. Furthermore, PPARαbinds and is activated by numerous fatty acids and fatty acid-derived compounds. PPARαgoverns biological processes by altering the expression of a large number of target genes. Accordingly, the specific role of PPARαis directly related to the biological function of its target genes. Here, we present an overview of the involvement of PPARαin lipid metabolism and other pathways through a detailed analysis of the different known or putative PPARαtarget genes. The emphasis is on gene regulation by PPARαin liver although many of the results likely apply to other organs and tissues as well.


PPAR Research ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Joo-In Park ◽  
Jong-Young Kwak

Colorectal cancer is one of the most common cancers in the world. Dietary fat intake is a major risk factor for colorectal cancer. Some nuclear hormone receptors play an important role in regulating nutrient metabolism and energy homeostasis. Among these receptors, special attention has been focused on the role of peroxisome proliferator-activated receptors (PPARs) in colorectal cancer, because PPARs are involved in regulation of lipid and carbohydrate metabolism. PPARs are ligand-activated intracellular transcription factors. The PPAR subfamily consists of three subtypes encoded by distinct genes named PPARα, PPARβ/δ, and PPARγ. PPARγis the most extensively studied subtype of PPARs. Even though many investigators have studied the expression and clinical implications of PPARs in colorectal cancer, there are still many controversies about the role of PPARs in colorectal cancer. In this paper, the recent progresses in understanding the role of PPARs in colorectal cancer are summarized.


2020 ◽  
Vol 21 (12) ◽  
pp. 4403 ◽  
Author(s):  
Sze Yuan Ho ◽  
Yuet Ping Kwan ◽  
Beiying Qiu ◽  
Alison Tan ◽  
Hannah Louise Murray ◽  
...  

Peroxisome proliferator-activated receptor (PPAR)β/δ is a member of the nuclear receptor superfamily of transcription factors, which plays fundamental roles in cell proliferation and differentiation, inflammation, adipogenesis, and energy homeostasis. Previous studies demonstrated a reduced choroidal neovascularization (CNV) in Pparβ/δ-deficient mice. However, PPARβ/δ’s role in physiological blood vessel formation and vessel remodeling in the retina has yet to be established. Our study showed that PPARβ/δ is specifically required for disordered blood vessel formation in the retina. We further demonstrated an increased arteriovenous crossover and wider venous caliber in Pparβ/δ-haplodeficient mice. In summary, these results indicated a critical role of PPARβ/δ in pathological angiogenesis and blood vessel remodeling in the retina.


2009 ◽  
Vol 107 (6) ◽  
pp. 1959-1964 ◽  
Author(s):  
Siming Li ◽  
Jiandie D. Lin

Circadian metabolic rhythms are fundamental to the control of nutrient and energy homeostasis, as well as the pathogenesis of metabolic disease, such as obesity, lipid disorders, and type 2 diabetes. This temporal organization of tissue metabolism is coordinated through reciprocal cross talk between the biological timing system and the metabolic regulatory networks. In this review, we discuss the signaling mechanisms that serve to couple metabolic regulation to the circadian pacemaker, in particular the role of the peroxisome proliferator-activated receptor-γ coactivator-1 transcriptional coactivators in integrating clock and energy metabolism.


2017 ◽  
Vol 474 (20) ◽  
pp. 3421-3437 ◽  
Author(s):  
Joji Kusuyama ◽  
Tomokazu Ohnishi ◽  
Kenjiro Bandow ◽  
Muhammad Subhan Amir ◽  
Kaori Shima ◽  
...  

Adipogenic differentiation plays a vital role in energy homeostasis and endocrine system. Several transcription factors, including peroxisome proliferator-activated receptor gamma 2 and CCAAT–enhancer-binding protein (C/EBP) α, β, and δ, are important for the process, whereas the stage-specific intracellular signal transduction regulating the onset of adipogenesis remains enigmatic. Here, we explored the functional role of c-jun N-terminal kinases (JNKs) in adipogenic differentiation using in vitro differentiation models of 3T3-L1 cells and primary adipo-progenitor cells. JNK inactivation with either a pharmacological inhibitor or JNK2-specific siRNA suppressed adipogenic differentiation, characterized by decreased lipid droplet appearance and the down-regulation of Adiponectin, fatty acid protein 4 (Fabp4), Pparg2, and C/ebpa expressions. Conversely, increased adipogenesis was observed by the inducible overexpression of p46JNK2 (JNK2-1), whereas it was not observed by that of p54JNK2 (JNK2-2), indicating a distinct role of p46JNK2. The essential role of JNK appears restricted to the early stage of adipogenic differentiation, as JNK inhibition in the later stages did not influence adipogenesis. Indeed, JNK phosphorylation was significantly induced at the onset of adipogenic differentiation. As for the transcription factors involved in early adipogenesis, JNK inactivation significantly inhibited the induction of C/ebpd, but not C/ebpb, during the initial stage of adipogenic differentiation. JNK activation increased C/ebpd mRNA and protein expression through the induction and phosphorylation of activating transcription factor 2 (ATF2) that binds to a responsive element within the C/ebpd gene promoter region. Taken together, these data indicate that constitutive JNK activity is specifically required for the initial stage differentiation events of adipocytes.


2020 ◽  
Vol 35 (9) ◽  
pp. 2072-2085
Author(s):  
Marta Santoro ◽  
Francesca De Amicis ◽  
Saveria Aquila ◽  
Daniela Bonofiglio

ABSTRACT Peroxisome proliferator-activated receptor gamma (PPARγ) acts as a ligand activated transcription factor and regulates processes, such as energy homeostasis, cell proliferation and differentiation. PPARγ binds to DNA as a heterodimer with retinoid X receptor and it is activated by polyunsaturated fatty acids and fatty acid derivatives, such as prostaglandins. In addition, the insulin-sensitizing thiazolidinediones, such as rosiglitazone, are potent and specific activators of PPARγ. PPARγ is present along the hypothalamic–pituitary–testis axis and in the testis, where low levels in Leydig cells and higher levels in Sertoli cells as well as in germ cells have been found. High amounts of PPARγ were reported in the normal epididymis and in the prostate, but the receptor was almost undetectable in the seminal vesicles. Interestingly, in the human and in pig, PPARγ protein is highly expressed in ejaculated spermatozoa, suggesting a possible role of PPARγ signaling in the regulation of sperm biology. This implies that both natural and synthetic PPARγ ligands may act directly on sperm improving its performance. Given the close link between energy balance and reproduction, activation of PPARγ may have promising metabolic implications in male reproductive functions. In this review, we first describe PPARγ expression in different compartments of the male reproductive axis. Subsequently, we discuss the role of PPARγ in both physiological and several pathological conditions related to the male fertility.


2015 ◽  
Vol 112 (19) ◽  
pp. 6074-6079 ◽  
Author(s):  
Jun Hong Park ◽  
Hong-Jun Kang ◽  
Yun Kyung Lee ◽  
Hyeog Kang ◽  
Jihyun Kim ◽  
...  

EWS (Ewing sarcoma) encodes an RNA/ssDNA binding protein that is frequently rearranged in a number of different cancers by chromosomal translocations. Physiologically, EWS has diverse and essential roles in various organ development and cellular processes. In this study, we uncovered a new role of EWS in mitochondrial homeostasis and energy metabolism. Loss of EWS leads to a significant decrease in mitochondria abundance and activity, which is caused by a rapid degradation of Peroxisome proliferator-activated receptor γ Coactivator (PGC-1α), a central regulator of mitochondria biogenesis, function, and cellular energy metabolism. EWS inactivation leads to increased ubiquitination and proteolysis of PGC-1α via proteasome pathway. Complementation of EWS in Ews-deficient cells restores PGC-1α and mitochondrial abundance. We found that expression of E3 ubiquitin ligase, FBXW7 (F-box/WD40 domain protein 7), is increased in the absence of Ews and depletion of Fbxw7 in Ews-null cells restores PGC-1α expression and mitochondrial density. Consistent with these findings, mitochondrial abundance and activity are significantly reduced in brown fat and skeletal muscles of Ews-deficient mice. Furthermore, expression of mitochondrial biogenesis, respiration and fatty acid β-oxidation genes is significantly reduced in the liver of Ews-null mice. These results demonstrate a novel role of EWS in mitochondrial and cellular energy homeostasis by controlling PGC-1α protein stability, and further implicate altered mitochondrial and energy metabolism in cancers harboring the EWS translocation.


Author(s):  
Rana A. Alaaeddine ◽  
Perihan A. Elzahhar ◽  
Ibrahim AlZaim ◽  
Wassim Abou-Kheir ◽  
Ahmed S.F. Belal ◽  
...  

: Emerging evidence supports an intertwining framework for the involvement of different inflammatory pathways in a common pathological background for a number of disorders. Of importance are pathways involving arachidonic acid metabolism by cyclooxygenase-2 (COX-2) and 15-lipoxygenase (15-LOX). Both enzyme activities and their products are implicated in a range of pathophysiological processes encompassing metabolic impairment leading to adipose inflammation and the subsequent vascular and neurological disorders, in addition to various pro-and anti-tumorigenic effects. A further layer of complexity is encountered by the disparate, and often reciprocal, modulatory effect COX-2 and 15-LOX activities and metabolites exert on each other or on other cellular targets, the most prominent of which is peroxisome proliferator-activated receptor gamma (PPARγ). Thus, effective therapeutic intervention with such multifaceted disorders requires the simultaneous modulation of more than one target. Here, we describe the role of COX-2, 15-LOX, and PPARγ in cancer and complications of metabolic disorders, highlight the value of designing multi-target directed ligands (MTDLs) modifying their activity, and summarize the available literature regarding the rationale and feasibility of design and synthesis of these ligands together with their known biological effects. We speculate on the potential impact of MTDLs in these disorders as well as emphasize the need for structured future effort to translate these early results facilitating the adoption of these, and similar, molecules in clinical research.


Sign in / Sign up

Export Citation Format

Share Document