scholarly journals PPAR Beta/Delta and the Hallmarks of Cancer

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1133 ◽  
Author(s):  
Nicole Wagner ◽  
Kay-Dietrich Wagner

Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear hormone receptor family. Three different isoforms, PPAR alpha, PPAR beta/delta and PPAR gamma have been identified. They all form heterodimers with retinoic X receptors to activate or repress downstream target genes dependent on the presence/absence of ligands and coactivators or corepressors. PPARs differ in their tissue expression profile, ligands and specific agonists and antagonists. PPARs attract attention as potential therapeutic targets for a variety of diseases. PPAR alpha and gamma agonists are in clinical use for the treatment of dyslipidemias and diabetes. For both receptors, several clinical trials as potential therapeutic targets for cancer are ongoing. In contrast, PPAR beta/delta has been suggested as a therapeutic target for metabolic syndrome. However, potential risks in the settings of cancer are less clear. A variety of studies have investigated PPAR beta/delta expression or activation/inhibition in different cancer cell models in vitro, but the relevance for cancer growth in vivo is less well documented and controversial. In this review, we summarize critically the knowledge of PPAR beta/delta functions for the different hallmarks of cancer biological capabilities, which interplay to determine cancer growth.

Author(s):  
C. Jennermann ◽  
S. A. Kliewer ◽  
D. C. Morris

Peroxisome proliferator-activated receptor gamma (PPARg) is a member of the nuclear hormone receptor superfamily and has been shown in vitro to regulate genes involved in lipid metabolism and adipocyte differentiation. By Northern analysis, we and other researchers have shown that expression of this receptor predominates in adipose tissue in adult mice, and appears first in whole-embryo mRNA at 13.5 days postconception. In situ hybridization was used to find out in which developing tissues PPARg is specifically expressed.Digoxigenin-labeled riboprobes were generated using the Genius™ 4 RNA Labeling Kit from Boehringer Mannheim. Full length PPAR gamma, obtained by PCR from mouse liver cDNA, was inserted into pBluescript SK and used as template for the transcription reaction. Probes of average size 200 base pairs were made by partial alkaline hydrolysis of the full length transcripts. The in situ hybridization assays were performed as described previously with some modifications. Frozen sections (10 μm thick) of day 18 mouse embryos were cut, fixed with 4% paraformaldehyde and acetylated with 0.25% acetic anhydride in 1.0M triethanolamine buffer. The sections were incubated for 2 hours at room temperature in pre-hybridization buffer, and were then hybridized with a probe concentration of 200μg per ml at 70° C, overnight in a humidified chamber. Following stringent washes in SSC buffers, the immunological detection steps were performed at room temperature. The alkaline phosphatase labeled, anti-digoxigenin antibody and detection buffers were purchased from Boehringer Mannheim. The sections were treated with a blocking buffer for one hour and incubated with antibody solution at a 1:5000 dilution for 2 hours, both at room temperature. Colored precipitate was formed by exposure to the alkaline phosphatase substrate nitrobluetetrazoliumchloride/ bromo-chloroindlylphosphate.


PPAR Research ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Sean R. Pyper ◽  
Navin Viswakarma ◽  
Yuzhi Jia ◽  
Yi-Jun Zhu ◽  
Joseph D. Fondell ◽  
...  

The peroxisome proliferator-activated receptor- (PPAR) plays a key role in lipid metabolism and energy combustion. Chronic activation of PPAR in rodents leads to the development of hepatocellular carcinomas. The ability of PPAR to induce expression of its target genes depends on Mediator, an evolutionarily conserved complex of cofactors and, in particular, the subunit 1 (Med1) of this complex. Here, we report the identification and characterization of PPAR-interacting cofactor (PRIC)-295 (PRIC295), a novel coactivator protein, and show that it interacts with the Med1 and Med24 subunits of the Mediator complex. PRIC295 contains 10 LXXLL signature motifs that facilitate nuclear receptor binding and interacts with PPAR and five other members of the nuclear receptor superfamily in a ligand-dependent manner. PRIC295 enhances the transactivation function of PPAR, PPAR, and ER. These data demonstrate that PRIC295 interacts with nuclear receptors such as PPAR and functions as a transcription coactivator underin vitroconditions and may play an important role in mediating the effectsin vivoas a member of the PRIC complex with Med1 and Med24.


2012 ◽  
Vol 32 (6) ◽  
pp. 619-629 ◽  
Author(s):  
Chanjuan Hao ◽  
Xuejia Cheng ◽  
Hongfei Xia ◽  
Xu Ma

The environmental obesogen hypothesis proposes that exposure to endocrine disruptors during developmental ‘window’ contributes to adipogenesis and the development of obesity. MEHP [mono-(2-ethylhexyl) phthalate], a metabolite of the widespread plasticizer DEHP [di-(2-ethylhexyl) phthalate], has been found in exposed organisms and identified as a selective PPARγ (peroxisome-proliferator-activated receptor γ) modulator. However, implication of MEHP on adipose tissue development has been poorly investigated. In the present study, we show the dose-dependent effects of MEHP on adipocyte differentiation and GPDH (glycerol-3-phosphate dehydrogenase) activity in the murine 3T3-L1 cell model. MEHP induced the expression of PPARγ as well as its target genes required for adipogenesis in vitro. Moreover, MEHP perturbed key regulators of adipogenesis and lipogenic pathway in vivo. In utero exposure to a low dose of MEHP significantly increased b.w. (body weight) and fat pad weight in male offspring at PND (postnatal day) 60. In addition, serum cholesterol, TAG (triacylglycerol) and glucose levels were also significantly elevated. These results suggest that perinatal exposure to MEHP may be expected to increase the incidence of obesity in a sex-dependent manner and can act as a potential chemical stressor for obesity and obesity-related disorders.


2016 ◽  
Vol 36 (7) ◽  
pp. 1180-1193 ◽  
Author(s):  
Nathan L. Price ◽  
Brandon Holtrup ◽  
Stephanie L. Kwei ◽  
Martin Wabitsch ◽  
Matthew Rodeheffer ◽  
...  

White adipose tissue (WAT) is essential for maintaining metabolic function, especially during obesity. The intronic microRNAs miR-33a and miR-33b, located within the genes encoding sterol regulatory element-binding protein 2 (SREBP-2) and SREBP-1, respectively, are transcribed in concert with their host genes and function alongside them to regulate cholesterol, fatty acid, and glucose metabolism. SREBP-1 is highly expressed in mature WAT and plays a critical role in promotingin vitroadipocyte differentiation. It is unknown whether miR-33b is induced during or involved in adipogenesis. This is in part due to loss of miR-33b in rodents, precludingin vivoassessment of the impact of miR-33b using standard mouse models. This work demonstrates that miR-33b is highly induced upon differentiation of human preadipocytes, along withSREBP-1. We further report that miR-33b is an important regulator of adipogenesis, as inhibition of miR-33b enhanced lipid droplet accumulation. Conversely, overexpression of miR-33b impaired preadipocyte proliferation and reduced lipid droplet formation and the induction of peroxisome proliferator-activated receptor γ (PPARγ) target genes during differentiation. These effects may be mediated by targeting of HMGA2, cyclin-dependent kinase 6 (CDK6), and other predicted miR-33b targets. Together, these findings demonstrate a novel role of miR-33b in the regulation of adipocyte differentiation, with important implications for the development of obesity and metabolic disease.


2005 ◽  
Vol 288 (3) ◽  
pp. H1037-H1043 ◽  
Author(s):  
Ernesto L. Schiffrin

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that heterodimerize with the retinoid X receptor and then modulate the function of many target genes. Three PPARs are known: α, β/δ, and γ. The better known are PPAR-α and PPAR-γ, which may be activated by different synthetic agonists, although the endogenous ligands are unknown. PPAR-α is involved in fatty acid oxidation and expressed in the liver, kidney, and skeletal muscle, whereas PPAR-γ is involved in fat cell differentiation, lipid storage, and insulin sensitivity. However, both have been shown to be present in variable amounts in cardiovascular tissues, including endothelium, smooth muscle cells, macrophages, and the heart. The activators of PPAR-α (fibrates) and PPAR-γ (thiazolidinediones or glitazones) antagonized the actions of angiotensin II in vivo and in vitro and exerted cardiovascular antioxidant and anti-inflammatory effects. PPAR activators lowered blood pressure, induced favorable effects on the heart, and corrected vascular structure and endothelial dysfunction in several rodent models of hypertension. Activators of PPARs may become therapeutic agents useful in the prevention of cardiovascular disease beyond their effects on carbohydrate and lipid metabolism. Some side effects, such as weight gain, as well as documented aggravation of advanced heart failure through fluid retention by glitazones, may, however, limit their therapeutic application in prevention of cardiovascular disease.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yong Gao ◽  
Dongfeng Han ◽  
Laisheng Sun ◽  
Qihua Huang ◽  
Guangchao Gai ◽  
...  

Peroxisome proliferator-activated receptor α (PPARα) is a member of the nuclear hormone receptor superfamily and functions as a transcription factor. Previous work showed that PPARα plays multiple roles in lipid metabolism in tissues such as cardiac and skeletal muscle, liver, and adipose tissue. Recent studies have discovered additional roles for PPARα in cell proliferation and metabolism, as well as tumor progression. PPARα is aberrantly expressed in various cancers, and activated PPARα inhibits the proliferation of some tumor cells. However, there have been no studies of PPARα in human gliomas. Here, we show that PPARα is expressed at lower levels in anaplastic gliomas and glioblastoma multiforme (GBM) tissue compared with low-grade gliomas tissue, and low expression is associated with poor patient prognosis. PPARα activates transcription of dynamin-3 opposite strand (DNMO3os), which encodes a cluster of miR-214, miR-199a-3p, and miR-199a-5p microRNAs. Of these, miR-214 is transcribed at particularly high levels. PPARα-induced miR-214 expression causes downregulation of its target E2F2. Finally, miR-214 overexpression inhibits glioma cell growth in vitro and in vivo by inducing cell cycle arrest in G0/G1. Collectively, these data uncover a novel role for a PPARα-miR-214-E2F2 pathway in controlling glioma cell proliferation.


2016 ◽  
Vol 8 (3) ◽  
pp. 147
Author(s):  
Rina Triana ◽  
Nurrani Mustika Dewi ◽  
Siska Darmayanti ◽  
Eka Herawati ◽  
Maria Novalentina ◽  
...  

BACKGROUND: Peroxisome proliferator-activated receptor (PPAR)-γ, or also known as nuclear receptor subfamily 1 group C member 3 (NR1C3), is a PPAR which serves as master regulator of adipocytes differentiation, and plays an important role in lipid metabolism or adipogenesis. Recent study showed that PPAR-γ is expressed in most tissue and also has critical impact in many metabolic homeostasis disorders.CONTENT: Dysregulation of PPAR-γ is correlated to the development of obesity, type 2 diabetes, atherosclerosis, cardiovascular disease, acute kidney injury, autoimmune disease, gastrointestinal disease and Alzheimer’s disease. Abundant number of new emerging compounds, with in vitro and in vivo effectiveness as natural and synthetic agonists of PPARs, are investigated, developed and used as the treatment of metabolic disorders of glucose and/or lipid and other diseases.SUMMARY: Based on all studies explanation, targeting PPAR-γ is proven to be a good therapeutic method for reducing negative effect of several metabolic homeostasis disorder. Now, many natural and synthetic agonists of PPARs are used as the treatment of metabolic disorders of glucose and/or lipid or another metabolic homeostasis disorder. Such agonists have different properties and specificities for individual PPARs receptors, different absorption and distribution, and distinctive gene expression profiles, which ultimately lead to different clinical outcomes.KEYWORDS: PPAR-γ, dysregulation, agonist, adipogenesis, metabolic disorder, homeostasis


2016 ◽  
Vol 16 (4) ◽  
pp. 497-511 ◽  
Author(s):  
Hong Wang ◽  
Xi Yan ◽  
Li-Ya Ji ◽  
Xi-Tuan Ji ◽  
Ping Wang ◽  
...  

Gliomas are the most common primary malignant brain tumor with poor prognosis, characterized by a highly heterogeneous cell population, extensive proliferation, and migration. A lot of molecular mechanisms regulate gliomas development and invasion, including abnormal expression of oncogenes and variation of epigenetic modification. MicroRNAs could affect cell growth and functions. Several reports have demonstrated that miR-139 plays multifunctions in kinds of solid tumors through different pathways. However, the antitumor mechanisms of this miR-139 are not unveiled in detail. In this study, we not only validated the low expression level of miR-139 in glioma tissues and cell lines but also detected the effect of miR-139 on modulating gliomas proliferation and invasion both in vitro and in vivo. We identified insulin-like growth factor 1 receptor, associate of Myc 1, and peroxisome proliferator-activated receptor γ coactivator 1β as direct targets of miR-139 and the levels of them were all inversely correlated with miR-139 in gliomas. Insulin like growth factor 1 receptor promoted gliomas invasion through Akt signaling and increased proliferation in the peroxisome proliferator-activated receptor γ coactivator 1β-dependent way. Associate of Myc 1 also facilitated gliomas progression by activating c-Myc pathway. Overexpression of the target genes could retrieve the antitumor function of miR-139, respectively, in different degrees. The nude mice transplantation tumor experiment displayed that glioma cells stably expressed miR-139 growth much slower in vivo than the negative control cells. Taken together, these findings suggested miR-139 acted as a favorable factor against gliomas progression and uncovered a novel regulatory mechanism, which may provide a new evidenced prognostic marker and therapeutic target for gliomas.


1998 ◽  
Vol 18 (6) ◽  
pp. 3483-3494 ◽  
Author(s):  
Ira G. Schulman ◽  
Gang Shao ◽  
Richard A. Heyman

ABSTRACT The ability of DNA sequence-specific transcription factors to synergistically activate transcription is a common property of genes transcribed by RNA polymerase II. The present work characterizes a unique form of intermolecular transcriptional synergy between two members of the nuclear hormone receptor superfamily. Heterodimers formed between peroxisome proliferator-activated receptor γ (PPARγ), an adipocyte-enriched member of the superfamily required for adipogenesis, and retinoid X receptors (RXRs) can activate transcription in response to ligands specific for either subunit of the dimer. Simultaneous treatment with ligands specific for both PPARγ and RXR has a synergistic effect on the transactivation of reporter genes and on adipocyte differentiation in cultured cells. Mutation of the PPARγ hormone-dependent activation domain (named τc or AF-2) inhibits the ability of RXR-PPARγ heterodimers to respond to ligands specific for either subunit. In contrast, the ability of RXR- and PPARγ-specific ligands to synergize does not require the hormone-dependent activation domain of RXR. The results of in vitro and in vivo experiments indicate that binding of ligands to RXR alters the conformation of the dimerization partner, PPARγ, and modulates the activity of the heterodimer in a manner independent of the RXR hormone-dependent activation domain.


2007 ◽  
Vol 28 (2) ◽  
pp. 687-704 ◽  
Author(s):  
Cameron N. Johnstone ◽  
Perry S. Mongroo ◽  
A. Sophie Rich ◽  
Michael Schupp ◽  
Mark J. Bowser ◽  
...  

ABSTRACT Parvin-β is a focal adhesion protein downregulated in human breast cancer cells. Loss of Parvin-β contributes to increased integrin-linked kinase activity, cell-matrix adhesion, and invasion through the extracellular matrix in vitro. The effect of ectopic Parvin-β expression on the transcriptional profile of MDA-MB-231 breast cancer cells, which normally do not express Parvin-β, was evaluated. Particular emphasis was placed upon propagating MDA-MB-231 breast cancer cells in three-dimensional culture matrices. Interestingly, Parvin-β reexpression in MDA-MB-231 cells increased the mRNA expression, serine 82 phosphorylation (mediated by CDK9), and activity of the nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARγ), and there was a concomitant increase in lipogenic gene expression as a downstream effector of PPARγ. Importantly, Parvin-β suppressed breast cancer growth in vivo, with associated decreased proliferation. These data suggest that Parvin-β might influence breast cancer progression.


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