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Meng X, Wang L, Du YC, Cheng D, Zeng T. PPARβ/δ as a promising molecular drug target for liver diseases: A focused review. Clin Res Hepatol Gastroenterol 2024; 48:102343. [PMID: 38641250 DOI: 10.1016/j.clinre.2024.102343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/03/2024] [Accepted: 04/17/2024] [Indexed: 04/21/2024]
Abstract
Various liver diseases pose great threats to humans. Although the etiologies of these liver diseases are quite diverse, they share similar pathologic phenotypes and molecular mechanisms such as oxidative stress, lipid and glucose metabolism disturbance, hepatic Kupffer cell (KC) proinflammatory polarization and inflammation, insulin resistance, and hepatic stellate cell (HSC) activation and proliferation. Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) is expressed in various types of liver cells with relatively higher expression in KCs and HSCs. Accumulating evidence has revealed the versatile functions of PPARβ/δ such as controlling lipid homeostasis, inhibiting inflammation, regulating glucose metabolism, and restoring insulin sensitivity, suggesting that PPARβ/δ may serve as a potential molecular drug target for various liver diseases. This article aims to provide a concise review of the structure, expression pattern and biological functions of PPARβ/δ in the liver and its roles in various liver diseases, and to discuss potential future research perspectives.
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Affiliation(s)
- Xin Meng
- Institute of Toxicology, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Lin Wang
- Institute of Toxicology, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Yan-Chao Du
- Jinan Institute for Product Quality Inspection, Jinan, Shandong 250102, China
| | - Dong Cheng
- Department of Health Test and Detection, Shandong Center for Disease Control and Prevention, Jinan, Shandong 250014, China.
| | - Tao Zeng
- Institute of Toxicology, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China.
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PPARβ/δ Augments IL-1β-Induced COX-2 Expression and PGE2 Biosynthesis in Human Mesangial Cells via the Activation of SIRT1. Metabolites 2022; 12:metabo12070595. [PMID: 35888719 PMCID: PMC9320509 DOI: 10.3390/metabo12070595] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/11/2022] [Accepted: 06/22/2022] [Indexed: 12/10/2022] Open
Abstract
Peroxisome proliferator-activated receptor β/δ (PPARβ/δ), a ligand-activated nuclear receptor, regulates lipid and glucose metabolism and inflammation. PPARβ/δ can exert an anti-inflammatory effect by suppressing proinflammatory cytokine production. Cyclooxygenase-2 (COX-2)-triggered inflammation plays a crucial role in the development of many inflammatory diseases, including glomerulonephritis. However, the effect of PPARβ/δ on the expression of COX-2 in the kidney has not been fully elucidated. The present study showed that PPARβ/δ was functionally expressed in human mesangial cells (hMCs), where its expression was increased by interleukin-1β (IL-1β) treatment concomitant with enhanced COX-2 expression and prostaglandin E2 (PGE2) biosynthesis. The treatment of hMCs with GW0742, a selective agonist of PPARβ/δ, or the overexpression of PPARβ/δ via an adenovirus-mediated approach significantly increased COX-2 expression and PGE2 production. PPARβ/δ could further augment the IL-1β-induced COX-2 expression and PGE2 production in hMCs. Moreover, both PPARβ/δ activation and overexpression markedly increased sirtuin 1 (SIRT1) expression. The inhibition or knockdown of SIRT1 significantly attenuated the effects of PPARβ/δ on the IL-1β-induced expression of COX-2 and PGE2 biosynthesis. Taken together, PPARβ/δ could augment the IL-1β-induced COX-2 expression and PGE2 production in hMCs via the SIRT1 pathway. Given the critical role of COX-2 in glomerulonephritis, PPARβ/δ may represent a novel target for the treatment of renal inflammatory diseases.
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Abstract
Our own studies and those of others have shown that defects in essential fatty acid (EFA) metabolism occurs in age-related disorders such as obesity, type 2 diabetes mellitus, hypertension, atherosclerosis, coronary heart disease, immune dysfunction and cancer. It has been noted that in all these disorders there could occur a defect in the activities of desaturases, cyclo-oxygenase (COX), and lipoxygenase (LOX) enzymes leading to a decrease in the formation of their long-chain products gamma-linolenic acid (GLA), arachidonic acid, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). This leads to an increase in the production of pro-inflammatory prostaglandin E2 (PGE2), thromboxanes (TXs), and leukotrienes (LTs) and a decrease in anti-inflammatory lipoxin A4, resolvins, protectins and maresins. All these bioactive molecules are termed as bioactive lipids (BALs). This imbalance in the metabolites of EFAs leads to low-grade systemic inflammation and at times acute inflammatory events at specific local sites that trigger the development of various age-related disorders such as obesity, type 2 diabetes mellitus, hypertension, coronary heart disease, atherosclerosis, and immune dysfunction as seen in rheumatoid arthritis, lupus, nephritis and other localized inflammatory conditions. This evidence implies that methods designed to restore BALs to normal can prevent age-related disorders and enhance longevity and health.
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Guo K, Hu L, Xi D, Zhao J, Liu J, Luo T, Ma Y, Lai W, Guo Z. PSRC1 overexpression attenuates atherosclerosis progression in apoE -/- mice by modulating cholesterol transportation and inflammation. J Mol Cell Cardiol 2018; 116:69-80. [PMID: 29378206 DOI: 10.1016/j.yjmcc.2018.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/16/2018] [Accepted: 01/20/2018] [Indexed: 01/13/2023]
Abstract
AIMS Human genome-wide association studies (GWAS) have found that proline/serine-rich coiled-coil 1 (PSRC1) encodes a protein that is associated with serum lipid levels and coronary artery disease. In addition, our previous study showed that the cholesterol efflux capacity is decreased in macrophages following a treatment silencing Psrc1, indicating that PSRC1 has anti-atherosclerotic effects. However, the role of PSRC1 in the development of atherosclerosis is unknown. This study aims to explore the effect of PSRC1 on atherosclerosis and its underlying mechanisms. METHOD AND RESULTS A recombinant adenovirus expressing Psrc1 (Ad-PSRC1) was constructed and transfected in RAW264.7 cells as well as injected intravenously into apoE-/- mice. The in vitro study showed that PSRC1 overexpression reduced the cellular cholesterol content, increased the cholesterol efflux capacity and inhibited foam cell formation by upregulating the expression of peroxisome proliferator-activated receptor γ (PPAR-γ) and liver X receptor α (LXR-α), which are key cholesterol transportation-related proteins. Infecting apoE-/- mice with Ad-PSRC1 inhibited the development of atherosclerotic lesions and enhanced atherosclerotic plaque stability. Consistent with these results, PSRC1 overexpression in apoE-/- mice decreased the plasma levels of TC, TG, LDL-C, TNF-α, IL-1β and IL-6, increased the plasma HDL-C levels and improved HDL function. Similarly, the PPAR-γ and LXR-α expression levels were upregulated in the liver and in peritoneal macrophages of PSRC1-overexpressing apoE-/- mice. Finally, the liver and peritoneal macrophages of apoE-/- mice displayed elevated expression of β-catenin, which is a direct downstream gene of PSRC1 and an upstream gene of PPAR-γ and LXR-α, but decreased activity of nuclear transcription factor (NF-κB), which acts as a key gene in the regulation of inflammation. CONCLUSIONS PSRC1 protects against the development of atherosclerosis and enhances the stability of plaques by modulating cholesterol transportation and inflammation in macrophages and the liver of apoE-/- mice.
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Affiliation(s)
- Kai Guo
- Department of Cardiology, Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Lu Hu
- Department of Cardiology, Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Dan Xi
- Department of Cardiology, Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Jinzhen Zhao
- Department of Cardiology, Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Jichen Liu
- Department of Cardiology, Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Tiantian Luo
- Department of Cardiology, Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Yusheng Ma
- Department of Cardiology, Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Wenyan Lai
- Department of Cardiology, Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Zhigang Guo
- Department of Cardiology, Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
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Wen D, Guo J, Jiang F, Huang C, Zhao Z, Lu G, Chen J, Qin L, Li Z, Wang X, Deng Z, Huang M, Chi CAS, On TJC, Zhong G. A rapid and sensitive UHPLC-MS/MS method for quantification of 83b1 in plasma and its application to bioavailability study in rats. J Pharm Biomed Anal 2017; 134:71-76. [PMID: 27886572 DOI: 10.1016/j.jpba.2016.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 10/20/2022]
Abstract
Great attentions have been drawn by quinoline for its broad bioactivity as anti-fungal, anti-bacterial and anti-tumor activities. Compared with cisplatin, 83b1, a quinoline derivative, showed equal activity in anti-tumor and lower cyctotoxicity in normal cell. In this study, a simple, rapid and sensitive method for determination of 83b1 in rat plasma using UHPLC-MS/MS was developed for the first time. Loratadine was used as an internal standard (IS). Separation was performed on an Xterra MS C18 column by isocratic elution using acetonitrile: water solution with 1‰ formic acid (90:10, v/v) as mobile phase at a flow rate of 0.3mL/min. A triple quadrupole mass spectrometer operating in the positive ion-switching electron spray ionization mode with selection reaction monitoring (SRM) was employed to determine 83b1 and IS transitions of m/z 321.82→147.84, 382.71→258.76 for 83b1 and Loratadine, respectively. The values of specificity, linearity and lower limit of quantification, intra- and inter- day precision and accuracy, extraction recovery, matrix effect and stability for this method satisfied the acceptable limits. The lower limit of quantification was 0.5ng/mL with a linear range of 0.5-1500ng/mL. The validated method was employed to study the bioavailability of 83b1 in rat by dosing with intravenous injection (1mg/kg) and gavage (10mg/kg), and the oral bioavailability of 83b1 in rat was calculated as 20.9±8.8%.
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Affiliation(s)
- Dingsheng Wen
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China.
| | - Jing Guo
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 Waihuan Road East, Guangzhou City, Guangdong Province 510006, China.
| | - Fulin Jiang
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China.
| | - Caishun Huang
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China.
| | - Zhenzhen Zhao
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China.
| | - Gui Lu
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 Waihuan Road East, Guangzhou City, Guangdong Province 510006, China.
| | - Jiangying Chen
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China.
| | - Liuyun Qin
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China
| | - Zhangwei Li
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China.
| | - Xueding Wang
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China.
| | - Zhuoan Deng
- State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Min Huang
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China.
| | - Chan Albert Sun Chi
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University, 132 Waihuan Road East, Guangzhou City, Guangdong Province 510006, China.
| | - Tang Johnny Cheuk On
- State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Guoping Zhong
- Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, North Campus, Sun Yat-Sen University, No.74, 2nd Yat-Sen Road, Yuexiu District, Guangzhou City, Guangdong Province 510080, China.
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Pun IHY, Chan D, Chan SH, Chung PY, Zhou YY, Law S, Lam AKY, Chui CH, Chan ASC, Lam KH, Tang JCO. Anti-cancer Effects of a Novel Quinoline Derivative 83b1 on Human Esophageal Squamous Cell Carcinoma through Down-Regulation of COX-2 mRNA and PGE 2. Cancer Res Treat 2016; 49:219-229. [PMID: 27456944 PMCID: PMC5266386 DOI: 10.4143/crt.2016.190] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 06/07/2016] [Indexed: 11/21/2022] Open
Abstract
PURPOSE 83b1 is a novel quinoline derivative that has been shown to inhibit cancer growth in human esophageal squamous cell carcinoma (ESCC). This study was conducted to comprehensively evaluate the cytotoxic effects of 83b1 on a series of ESCC cell lines and investigate the mechanisms by which 83b1 suppresses cancer growth based on molecular docking analysis. MATERIALS AND METHODS A series of ESCC and nontumor immortalized cell lines were exposed to 83b1 and cisplatin (CDDP) in a dose-dependent manner, and the cytotoxicity was examined by a MTS assay kit. Prediction of the molecular targets of 83b1 was conducted by molecular docking analysis. Expression of cyclooxygenase 2 (COX-2) mRNA and COX-2-derived prostaglandin E2 (PGE2) were measured by quantitative real-time polymerase chain reaction and enzymelinked immuno-sorbent assay, respectively. In vivo anti-tumor effect was determined using a nude mice xenografted model transplanted with an ESCC cell line, KYSE-450. RESULTS 83b1 showed the significant anti-cancer effects on all ESCC cell lines compared to CDDP; however, 83b1 revealed much lower toxic effects on non-tumor cell lines than CDDP. The predicted molecular target of 83b1 is peroxisome proliferator-activated receptor delta (PPARδ), which is a widely known oncoprotein. Additionally the expression of COX-2 mRNA and COX-2-derived PGE2 were down-regulated by 83b1 in a dose-dependent manner in ESCC cell lines. Furthermore, 83b1 was shown to significantly reduce the tumor size in nude mice xenograft. CONCLUSION The results of this study suggest that the potential anti-cancer effects of 83b1 on human esophageal cancers occur through the possible oncotarget, PPARδ, and down-regulation of the cancer related genes and molecules.
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Affiliation(s)
- Ivan Ho Yuen Pun
- State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Dessy Chan
- State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Sau Hing Chan
- State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Po Yee Chung
- State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Yuan Yuan Zhou
- State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Simon Law
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Alfred King Yin Lam
- Department of Pathology, Griffith Medical School and Griffith Health Institute, Griffith University, Gold Coast, Queensland, Australia
| | - Chung Hin Chui
- Clinical Division, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | | | - Kim Hung Lam
- State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Johnny Cheuk On Tang
- State Key Laboratory of Chirosciences, Lo Ka Chung Centre for Natural Anti-cancer Drug Development, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
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Balandaram G, Kramer LR, Kang BH, Murray IA, Perdew GH, Gonzalez FJ, Peters JM. Ligand activation of peroxisome proliferator-activated receptor-β/δ suppresses liver tumorigenesis in hepatitis B transgenic mice. Toxicology 2016; 363-364:1-9. [PMID: 27427494 PMCID: PMC5278792 DOI: 10.1016/j.tox.2016.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/05/2016] [Accepted: 07/13/2016] [Indexed: 12/13/2022]
Abstract
Peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) inhibits steatosis and inflammation, known risk factors for liver cancer. In this study, the effect of ligand activation of PPARβ/δ in modulating liver tumorigenesis in transgenic hepatitis B virus (HBV) mice was examined. Activation of PPARβ/δ in HBV mice reduced steatosis, the average number of liver foci, and tumor multiplicity. Reduced expression of hepatic CYCLIN D1 and c-MYC, tumor necrosis factor alpha (Tnfa) mRNA, serum levels of alanine aminotransaminase, and an increase in apoptotic signaling was also observed following ligand activation of PPARβ/δ in HBV mice compared to controls. Inhibition of Tnfa mRNA expression was not observed in wild-type hepatocytes. Ligand activation of PPARβ/δ inhibited lipopolysaccharide (LPS)-induced mRNA expression of Tnfa in wild-type, but not in Pparβ/δ-null Kupffer cells. Interestingly, LPS-induced expression of Tnfa mRNA was also inhibited in Kupffer cells from a transgenic mouse line that expressed a DNA binding mutant form of PPARβ/δ compared to controls. Combined, these results suggest that ligand activation of PPARβ/δ attenuates hepatic tumorigenesis in HBV transgenic mice by inhibiting steatosis and cell proliferation, enhancing hepatocyte apoptosis, and modulating anti-inflammatory activity in Kupffer cells.
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Affiliation(s)
- Gayathri Balandaram
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - Lance R Kramer
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - Boo-Hyon Kang
- Chemon Nonclinical Research Institute, 240 Nampyeong-ro, Yangji-myeon, Cheoin-gu, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Iain A Murray
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - Gary H Perdew
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA
| | - Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, Bethesda, MD, USA
| | - Jeffrey M Peters
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, USA.
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Yao L, Han C, Song K, Zhang J, Lim K, Wu T. Omega-3 Polyunsaturated Fatty Acids Upregulate 15-PGDH Expression in Cholangiocarcinoma Cells by Inhibiting miR-26a/b Expression. Cancer Res 2015; 75:1388-98. [PMID: 25691459 DOI: 10.1158/0008-5472.can-14-2561] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 01/26/2015] [Indexed: 12/19/2022]
Abstract
Prostaglandin E2 (PGE2) is a proinflammatory lipid mediator that promotes cancer growth. The 15-hydroxyprostaglandin dehydrogenase (15-PGDH) catalyzes oxidation of the 15(S)-hydroxyl group of PGE2, leading to its inactivation. Therefore, 15-PGDH induction may offer a strategy to treat cancers that are driven by PGE2, such as human cholangiocarcinoma. Here, we report that omega-3 polyunsaturated fatty acids (ω-3 PUFA) upregulate 15-PGDH expression by inhibiting miR-26a and miR-26b, thereby contributing to ω-3 PUFA-induced inhibition of human cholangiocarcinoma cell growth. Treatment of human cholangiocarcinoma cells (CCLP1 and TFK-1) with ω-3 PUFA (DHA) or transfection of these cells with the Fat-1 gene (encoding Caenorhabditis elegans desaturase, which converts ω-6 PUFA to ω-3 PUFA) significantly increased 15-PGDH enzymes levels, but with little effect on the activity of the 15-PGDH gene promoter. Mechanistic investigations revealed that this increase in 15-PGDH levels in cells was mediated by a reduction in the expression of miR-26a and miR-26b, which target 15-PGDH mRNA and inhibit 15-PGDH translation. These findings were extended by the demonstration that overexpressing miR-26a or miR-26b decreased 15-PGDH protein levels, reversed ω-3 PUFA-induced accumulation of 15-PGDH protein, and prevented ω-3 PUFA-induced inhibition of cholangiocarcinoma cell growth. We further observed that ω-3 PUFA suppressed miR-26a and miR-26b by inhibiting c-myc, a transcription factor that regulates miR-26a/b. Accordingly, c-myc overexpression enhanced expression of miR-26a/b and ablated the ability of ω-3 PUFA to inhibit cell growth. Taken together, our results reveal a novel mechanism for ω-3 PUFA-induced expression of 15-PGDH in human cholangiocarcinoma and provide a preclinical rationale for the evaluation of ω-3 PUFA in treatment of this malignancy.
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Affiliation(s)
- Lu Yao
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Chang Han
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Kyoungsub Song
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Jinqiang Zhang
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Kyu Lim
- Department of Biochemistry, College of Medicine, Cancer Research Institute and Infection Signaling, Network Research Center, Chungnam National University, Daejeon, Korea
| | - Tong Wu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana.
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Neels JG, Grimaldi PA. Physiological functions of peroxisome proliferator-activated receptor β. Physiol Rev 2014; 94:795-858. [PMID: 24987006 DOI: 10.1152/physrev.00027.2013] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The peroxisome proliferator-activated receptors, PPARα, PPARβ, and PPARγ, are a family of transcription factors activated by a diversity of molecules including fatty acids and fatty acid metabolites. PPARs regulate the transcription of a large variety of genes implicated in metabolism, inflammation, proliferation, and differentiation in different cell types. These transcriptional regulations involve both direct transactivation and interaction with other transcriptional regulatory pathways. The functions of PPARα and PPARγ have been extensively documented mainly because these isoforms are activated by molecules clinically used as hypolipidemic and antidiabetic compounds. The physiological functions of PPARβ remained for a while less investigated, but the finding that specific synthetic agonists exert beneficial actions in obese subjects uplifted the studies aimed to elucidate the roles of this PPAR isoform. Intensive work based on pharmacological and genetic approaches and on the use of both in vitro and in vivo models has considerably improved our knowledge on the physiological roles of PPARβ in various cell types. This review will summarize the accumulated evidence for the implication of PPARβ in the regulation of development, metabolism, and inflammation in several tissues, including skeletal muscle, heart, skin, and intestine. Some of these findings indicate that pharmacological activation of PPARβ could be envisioned as a therapeutic option for the correction of metabolic disorders and a variety of inflammatory conditions. However, other experimental data suggesting that activation of PPARβ could result in serious adverse effects, such as carcinogenesis and psoriasis, raise concerns about the clinical use of potent PPARβ agonists.
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Affiliation(s)
- Jaap G Neels
- Institut National de la Santé et de la Recherche Médicale U 1065, Mediterranean Center of Molecular Medicine (C3M), Team "Adaptive Responses to Immuno-metabolic Dysregulations," Nice, France; and Faculty of Medicine, University of Nice Sophia-Antipolis, Nice, France
| | - Paul A Grimaldi
- Institut National de la Santé et de la Recherche Médicale U 1065, Mediterranean Center of Molecular Medicine (C3M), Team "Adaptive Responses to Immuno-metabolic Dysregulations," Nice, France; and Faculty of Medicine, University of Nice Sophia-Antipolis, Nice, France
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Lee MY, Lee YJ, Kim YH, Lee SH, Park JH, Kim MO, Suh HN, Ryu JM, Yun SP, Jang MW, Han HJ. Role of Peroxisome Proliferator-Activated Receptor (PPAR)δ in Embryonic Stem Cell Proliferation. Int J Stem Cells 2014; 2:28-34. [PMID: 24855517 DOI: 10.15283/ijsc.2009.2.1.28] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2009] [Indexed: 01/15/2023] Open
Abstract
The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the nuclear receptor family. It is well known that PPARs function as regulators of lipid and lipoprotein metabolism and glucose homeostasis, as well as influence cellular proliferation, differentiation and apoptosis. However, the role of the PPARs with regard to embryonic stem (ES) cells remains unknown. We will review the function of the PPARδ, one of the three PPAR isoforms, α, δ (also called β/δ), and γ, in ES cells and its role in embryo development. In addition, pluripotent mouse ES cells can be expanded in large numbers in vitro due to the process of symmetrical self-renewal. Here we describe how PPARδ sustains ES cell proliferation.
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Affiliation(s)
- Min Young Lee
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Yu Jin Lee
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Yun Hee Kim
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Sang Hun Lee
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Jae Hong Park
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Mi Ok Kim
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Han Na Suh
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Jung Min Ryu
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Seung Pil Yun
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Min Woo Jang
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
| | - Ho Jae Han
- Department of Veterinary Physiology, Biotherapy Human Resources Center (BK21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
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11
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Mond M, Alexiadis M, Eriksson N, Davis MJ, Muscat GEO, Fuller PJ, Gilfillan C. Nuclear receptor expression in human differentiated thyroid tumors. Thyroid 2014; 24:1000-11. [PMID: 24559275 DOI: 10.1089/thy.2013.0509] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Nuclear receptors (NRs) play a key role in endocrine signaling and metabolism and are important therapeutic targets in a number of hormone-dependent malignancies. Studies on the role of NRs in thyroid cancer are limited. OBJECTIVE The objective of the study was to examine systematically the expression of the 48 human NRs in a series of benign and malignant thyroid tissues. Within the papillary carcinoma cohort, we sought to determine if NR expression differed significantly by BRAF mutation status. PATIENTS AND METHODS RNA was isolated from multinodular goiter (MNG; n=6), papillary carcinoma (PTC, n=14), follicular carcinoma (FC; n=5), and Hürthle cell carcinoma (HCC; n=7). The 48 human NRs were profiled in this panel by quantitative real time polymerase chain reaction. Protein expression for selected NRs (Rev-erbα and LXR-β) was examined by immunohistochemistry (IHC) on tissue microarrays comprising benign and malignant thyroid tissues. RESULTS Across all groups of benign and malignant thyroid tissue, there was prominent expression of LXR-β and ROR-γ. Key findings in PTC were marked overexpression of RXR-γ and Rev-erbα compared to MNG. Within the PTC cohort, when BRAF(V600E) tumors were compared with wild type BRAF, there was relative upregulation of RXR-γ and Rev-erbα and downregulation of AR, ERR-γ, and ROR-γ. In FC, EAR-2 was overexpressed, while PPAR-α and PPAR-δ were underexpressed compared to MNG. The NR expression profile of HCC was distinct, characterized by significant downregulation of a wide range of NRs. IHC for Rev-erbα and LXR-β localized protein expression to the tumor cells. Moderate to strong Rev-erbα immunostaining was seen in 22 out of 23 PTC, and, overall, staining was stronger than in the benign group. CONCLUSIONS These results represent the first systematic examination of NR expression in thyroid cancer. Our finding of tumor-specific patterns of NR expression, as well as significant differences in NR expression between BRAF(V600E) and wild type BRAF PTC, provides a basis for further mechanistic studies and highlights potential novel therapeutic targets for this malignancy.
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Affiliation(s)
- Michael Mond
- 1 Prince Henry's Institute of Medical Research , Clayton, Australia
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12
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Elsherbiny ME, Emara M, Godbout R. Interaction of brain fatty acid-binding protein with the polyunsaturated fatty acid environment as a potential determinant of poor prognosis in malignant glioma. Prog Lipid Res 2013; 52:562-70. [PMID: 23981365 DOI: 10.1016/j.plipres.2013.08.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 07/29/2013] [Accepted: 08/13/2013] [Indexed: 11/29/2022]
Abstract
Malignant gliomas are the most common adult brain cancers. In spite of aggressive treatment, recurrence occurs in the great majority of patients and is invariably fatal. Polyunsaturated fatty acids are abundant in brain, particularly ω-6 arachidonic acid (AA) and ω-3 docosahexaenoic acid (DHA). Although the levels of ω-6 and ω-3 polyunsaturated fatty acids are tightly regulated in brain, the ω-6:ω-3 ratio is dramatically increased in malignant glioma, suggesting deregulation of fundamental lipid homeostasis in brain tumor tissue. The migratory properties of malignant glioma cells can be modified by altering the ratio of AA:DHA in growth medium, with increased migration observed in AA-rich medium. This fatty acid-dependent effect on cell migration is dependent on expression of the brain fatty acid binding protein (FABP7) previously shown to bind DHA and AA. Increased levels of enzymes involved in eicosanoid production in FABP7-positive malignant glioma cells suggest that FABP7 is an important modulator of AA metabolism. We provide evidence that increased production of eicosanoids in FABP7-positive malignant glioma growing in an AA-rich environment contributes to tumor infiltration in the brain. We discuss pathways and molecules that may underlie FABP7/AA-mediated promotion of cell migration and FABP7/DHA-mediated inhibition of cell migration in malignant glioma.
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Affiliation(s)
- Marwa E Elsherbiny
- Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2, Canada
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13
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Peroxisome proliferator-activated receptor (PPAR)β/δ, a possible nexus of PPARα- and PPARγ-dependent molecular pathways in neurodegenerative diseases: Review and novel hypotheses. Neurochem Int 2013; 63:322-30. [PMID: 23811400 DOI: 10.1016/j.neuint.2013.06.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Revised: 06/11/2013] [Accepted: 06/15/2013] [Indexed: 01/03/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARα, -β/δ and -γ) are lipid-activated transcription factors. Synthetic PPARα and PPARγ ligands have neuroprotective properties. Recently, PPARβ/δ activation emerged as the focus of a novel approach for the treatment of a wide range of neurodegenerative diseases. To fill the gap of knowledge about the role of PPARβ/δ in brain, new hypotheses about PPARβ/δ involvement in neuropathological processes are requested. In this paper, we describe a novel hypothesis, claiming the existence of tight interactions between the three PPAR isotypes, which we designate the "PPAR triad". We propose that PPARβ/δ has a central control of the PPAR triad. The majority of studies analyze the regulation only by one of the PPAR isotypes. A few reports describe the mutual regulation of expression levels of all three PPAR isotypes by PPAR agonists. Analysis of these studies where pairwise interactions of PPARs were described allows us to support the existence of the PPAR triad with central role for PPARβ/δ. In the present review, we propose the hypothesis that in a wide range of brain disorders, PPARβ/δ plays a central role between PPARα and PPARγ. Finally, we prove the advantages of the PPAR triad concept by describing hypotheses of PPARβ/δ involvement in the regulation of myelination, glutamate-induced neurotoxicity, and signaling pathways of reactive oxygen species/NO/Ca(2+).
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14
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Challet E, Denis I, Rochet V, Aïoun J, Gourmelen S, Lacroix H, Goustard-Langelier B, Papillon C, Alessandri JM, Lavialle M. The role of PPARβ/δ in the regulation of glutamatergic signaling in the hamster suprachiasmatic nucleus. Cell Mol Life Sci 2013; 70:2003-14. [PMID: 23269438 PMCID: PMC11113465 DOI: 10.1007/s00018-012-1241-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 11/15/2012] [Accepted: 12/10/2012] [Indexed: 12/28/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptor superfamily and function as transcription factors that regulate gene expression in numerous biological processes. Although the PPARβ/δ subtype is highly expressed in the brain, its physiological roles in neuronal function remain to be elucidated. In this study, we examined the presence of PPARβ/δ in the master circadian clock of the Syrian hamster and investigated its putative functional role in this structure. In mammals, the central circadian clock, located in the suprachiasmatic nucleus (SCN), is entrained by the light-dark (LD) cycle via photic6 signals conveyed by a direct pathway whose terminals release glutamate. Using immunocytochemical and qRT-PCR analysis, we demonstrated that the rhythmic expression of PPAR β/δ within the SCN of hamsters raised under an LD cycle was detectable only at the transcriptional level when the hamsters were maintained under constant darkness (DD). The increase in the number of immunoreactive PPARβ/δ cells observed under DD after light stimulation during the early subjective night (CT14), but not during the subjective day (CT06), demonstrated that the expression of PPARβ/δ can be up-regulated according to the photosensitive phase of the circadian clock. All of the PPARβ/δ-positive cells in the SCN also expressed the glutamate receptor NMDAR1. Moreover, we demonstrated that at the photosensitive point (CT14), the administration of L-16504, a specific agonist of PPARβ/δ, amplified the phase delay of the locomotor response induced by a light pulse. Taken together, these data suggest that PPARβ/δ activation modulates glutamate release that mediates entrainment of the circadian clock by light.
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Affiliation(s)
- Etienne Challet
- Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, UPR 3212 CNRS, University of Strasbourg, 67084 Strasbourg cedex, France
| | - Isabelle Denis
- INRA, UR 909 Nutrition et Régulation Lipidique des Fonctions Cérébrales, 78352 Jouy-en-Josas, France
| | - Violaine Rochet
- INRA, UR 909 Nutrition et Régulation Lipidique des Fonctions Cérébrales, 78352 Jouy-en-Josas, France
| | - Josiane Aïoun
- INRA, UR 909 Nutrition et Régulation Lipidique des Fonctions Cérébrales, 78352 Jouy-en-Josas, France
| | - Sylviane Gourmelen
- Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, UPR 3212 CNRS, University of Strasbourg, 67084 Strasbourg cedex, France
| | - Herminie Lacroix
- INRA, UR 909 Nutrition et Régulation Lipidique des Fonctions Cérébrales, 78352 Jouy-en-Josas, France
| | | | - Catherine Papillon
- INRA, UR 909 Nutrition et Régulation Lipidique des Fonctions Cérébrales, 78352 Jouy-en-Josas, France
| | - Jean-Marc Alessandri
- INRA, UR 909 Nutrition et Régulation Lipidique des Fonctions Cérébrales, 78352 Jouy-en-Josas, France
| | - Monique Lavialle
- INRA, UR 909 Nutrition et Régulation Lipidique des Fonctions Cérébrales, 78352 Jouy-en-Josas, France
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15
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Radisavljevic Z. AKT as locus of cancer positive feedback loops and extreme robustness. J Cell Physiol 2013; 228:522-4. [PMID: 22833426 DOI: 10.1002/jcp.24167] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 07/16/2012] [Indexed: 12/21/2022]
Abstract
A positive feedback loops induce extreme robustness in metastatic cancer, relapsed leukemia, myeloma or lymphoma. The loops are generated by the signaling interactome networks of autocrine and paracrine elements from cancer hypoxic microenvironment. The elements of the networks are signaling proteins synthesized in hypoxic microenvironment such as the vascular endothelial growth factor, HIF-1α, hepatocyte growth factor, and molecules nitric oxide and H(2)O(2). The signals from upstream or rebound downstream pathways are amplified by the short or wide positive feedback loops, hyperstimulating AKT-inducing cancer extreme robustness. Targeting the phosphorylated AKT locus by an oxidant/antioxidant modulation induces collapse of positive feedback loops and establishment of negative feedback loops leading to stability of the system and disappearance of cancer extreme robustness. This is a new principle for the conversion of cancer positive loops into negative feedback loops by the locus chemotherapy.
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Affiliation(s)
- Ziv Radisavljevic
- Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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16
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Sozmen M, Kabak YB, Gulbahar MY, Gacar A, Karayigit MO, Guvenc T, Yarim M. Immunohistochemical characterization of peroxisome proliferator-activated receptors in canine normal testis and testicular tumours. J Comp Pathol 2012; 149:10-8. [PMID: 23219070 DOI: 10.1016/j.jcpa.2012.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 09/05/2012] [Accepted: 09/25/2012] [Indexed: 11/19/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear hormone receptor superfamily. Recent studies have demonstrated that PPARs regulate lipid metabolism and are expressed in various cancers. The aim of the present study was to investigate the expression of PPAR-α, -β and -γ in normal canine testicular tissue and canine testicular tumours (CTTs). Expression of PPAR-α, -β and -γ was greater (P <0.05) than in normal testicular tissue. PPARs were therefore induced in CTTs and they may play a role in the biology of these tumours.
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Affiliation(s)
- M Sozmen
- Department of Pathology, Faculty of Veterinary Medicine, Ondokuz Mayis University, TR-55139 Samsun, Turkey.
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17
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Xu M, Zuo X, Shureiqi I. Targeting peroxisome proliferator-activated receptor-β/δ in colon cancer: how to aim? Biochem Pharmacol 2012; 85:607-611. [PMID: 23041232 DOI: 10.1016/j.bcp.2012.09.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 09/26/2012] [Accepted: 09/27/2012] [Indexed: 12/18/2022]
Abstract
Peroxisome proliferator-activated receptor-β/δ (PPARδ) is a ubiquitously expressed, ligand-activated transcriptional factor that performs diverse critical functions in normal cells (e.g., fatty acid metabolism, obesity, apoptosis, and inflammation). Various studies in humans have found that PPARδ is upregulated in primary colorectal cancers; however, these findings have been challenged by those of other reports. Similarly, various in vitro and in vivo mechanistic pre-clinical models have yielded data demonstrating that PPARδ promotes colonic tumorigenesis, but other models have yielded data that contradicts this notion. Definitive studies are therefore needed to establish the exact role of PPARδ in human colorectal tumorigenesis and to provide a theoretical basis for PPARδ therapeutic targeting.
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Affiliation(s)
- Min Xu
- Department of Gastrointestinal Medical Oncology, Unit 0426, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030-4009, USA; Department of Gastroenterology, Affiliated Hospital of Jiangsu University, 438 Jiefang Road, Zhenjiang, Jiangsu 212001, PR China
| | - Xiangsheng Zuo
- Department of Gastrointestinal Medical Oncology, Unit 0426, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030-4009, USA
| | - Imad Shureiqi
- Department of Gastrointestinal Medical Oncology, Unit 0426, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030-4009, USA.
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18
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Dai R, Li J, Fu J, Chen Y, Wang R, Zhao X, Luo T, Zhu J, Ren Y, Cao J, Qian Y, Li N, Wang H. The tyrosine kinase c-Met contributes to the pro-tumorigenic function of the p38 kinase in human bile duct cholangiocarcinoma cells. J Biol Chem 2012; 287:39812-23. [PMID: 23024367 DOI: 10.1074/jbc.m112.406520] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pro-tumorigenic function of the p38 kinase plays a critical role in human cholangiocarcinogenesis. However, the underlying mechanism remains incompletely understood. Here, we report that c-Met, the tyrosine kinase receptor for hepatocyte growth factor (HGF), contributes to the pro-tumorigenic ability of p38 in human cholangiocarcinoma cells. Both p38 and c-Met promote the proliferation and invasion of human cholangiocarcinoma cells. Importantly, inhibition or knockdown of p38 decreased the basal activation of c-Met. Tyrosine phosphatase inhibitor studies revealed that p38 promotes the activity of c-Met, at least in part, by inhibiting dephosphorylation of the receptor. Moreover, density enhanced phosphatase-1 (DEP-1) is involved in p38-mediated inhibiting dephosphorylation of c-Met. Furthermore, p38 inhibits the degradation of c-Met. Taken together, these data provide a potential mechanism to explain how p38 promotes human cholangiocarcinoma cell proliferation and invasion. We propose that the link between p38 and c-Met is implicated in the progression of human cholangiocarcinoma.
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Affiliation(s)
- Rongyang Dai
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, Second Military Medical University, Shanghai 200438
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19
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Jeong CY, Hah YS, Cho BI, Lee SM, Joo YT, Jung EJ, Jeong SH, Lee YJ, Choi SK, Ha WS, Park ST, Hong SC. Fatty acid-binding protein 5 promotes cell proliferation and invasion in human intrahepatic cholangiocarcinoma. Oncol Rep 2012; 28:1283-92. [PMID: 22825302 DOI: 10.3892/or.2012.1922] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 06/21/2012] [Indexed: 01/19/2023] Open
Abstract
Intrahepatic cholangiocarcinoma (ICC) is a rare primary malignant liver tumor with an extremely poor prognosis. Recently its incidence has increased, however, little attention has been directed to factors related to its molecular carcinogenesis, including oncogenes, tumor suppressor genes and cell cycle-related proteins. ICC is generally characterized by strong proliferation, invasion and early metastasis. These biological behaviors of ICC, with respect to the genetic and molecular aspects, remain to be clarified. In this study, we performed a proteomic analysis to identify the proteomic alterations associated with carcinogenesis of ICC. Protein expression profiles of sixteen cases of ICC were compared with those of adjacent non-involved bile duct tissue. Among the 151 protein spots that showed a statistically significant expression difference (P<0.05), there were 50 spots with significantly increased intensity (3-fold increase) and 17 spots with decreased intensity (3-fold decrease) in cancerous tissues. Of these, increased expression of fatty acid-binding protein 5 (FABP5) was further confirmed by western blot analysis and immunohistochemical analysis. Immunohistochemical analysis of FABP5 expression in tumor specimens obtained from 43 patients with mass-forming (MF) type ICC showed a positive correlation of FABP5 immunoreactivity with tumor size (P=0.047), lymph node metastasis (P=0.013), angioinvasion (P=0.032) and staging (P=0.007). In addition, silencing FABP5 with short hairpin RNA (shRNA) suppressed cell proliferation and invasiveness in HuCCT1 cells, and conversely, overexpression of FABP5 in FABP5-negative Hep3B cells increased cell proliferation and invasiveness. Our study shows that FABP5 is significantly overexpressed in ICC combined lymph node metastasis and is involved in cell proliferation and invasion in vitro. Our data suggest that FABP5 may be associated with tumor progression in ICC.
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Affiliation(s)
- Chi-Young Jeong
- Department of Surgery, Gyeongsang National University School of Medicine, Institute of Health Sciences, Gyeongsang National University Hospital, Jinju 660-751, Republic of Korea
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20
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Arachidonic acid regulation of the cytosolic phospholipase A2α/cyclooxygenase-2 pathway in mouse endometrial stromal cells. Fertil Steril 2012; 97:1199-205.e1-9. [DOI: 10.1016/j.fertnstert.2012.02.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 02/08/2012] [Accepted: 02/08/2012] [Indexed: 11/22/2022]
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21
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Zhao L, Gandhi CR, Gao ZH. Involvement of cytosolic phospholipase A2 alpha signalling pathway in spontaneous and transforming growth factor-beta-induced activation of rat hepatic stellate cells. Liver Int 2011; 31:1565-73. [PMID: 22093332 DOI: 10.1111/j.1478-3231.2011.02632.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Accepted: 08/01/2011] [Indexed: 12/23/2022]
Abstract
BACKGROUND Hepatic stellate cells (HSCs) are extracellular matrix-producing cells that play a pivotal role in liver fibrogenesis. During liver injury and when cells are placed in vitro, HSCs undergo phenotypic transition from quiescent retinoid-storing cells to activated retinoid-deficient myofibroblast-like cells. Although several mediators including reactive oxygen species, platelet derived growth factor, transforming growth factor-beta (TGF-β) and tumour necrosis factor-alpha (TNF-α) were implicated in HSC activation, the cellular signalling pathways that regulate this process remain incompletely defined. AIMS The objectives of this study were to evaluate the role of cytosolic phospholipase A(2) alpha (cPLA(2)α) and peroxisome proliferator-activated receptor-beta/delta (PPAR-β/δ) in HSC activation. METHODS Rat HSCs were isolated, purified, cultured and stimulated with TGF-β1 in the presence or absence of the selective cPLA(2)α inhibitor, arachidonyltrifluoromethyl ketone (AACOCF(3)). The activation status of HSC was evaluated by immunofluorescent staining of alpha-smooth muscle actin (α-SMA) and by measuring the expression of cPLA(2)α, cyclooxygenase 2 (COX-2) and PPAR-β/δ using western blot analysis. RESULTS Rapid and significant increase in cPLA(2)α expression was observed during activation of HSCs. These events preceded the elevation of PPAR-β/δ and the expression of α-SMA. Elevated expression of cPLA(2)α, but not COX-2, was also observed during TGF-β-induced HSC activation. The TGF-β-induced α-SMA expression was blocked by AACOCF(3). Furthermore, transfection of a cPLA(2)α expression vector enhanced the transcription activity of PPAR-β/δ and the expression of α-SMA in HSCs. CONCLUSION cPLA(2)α-mediated induction of PPAR-β/δ is a novel intracellular signalling pathway in spontaneous and TGF-β induced activation of HSCs and could be a potential therapeutic target for the treatment of liver fibrosis.
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Affiliation(s)
- Liena Zhao
- Department of Pathology and Laboratory Medicine, University of Calgary and Calgary Laboratory Services, Calgary, AB, Canada
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22
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Cohen G, Riahi Y, Shamni O, Guichardant M, Chatgilialoglu C, Ferreri C, Kaiser N, Sasson S. Role of lipid peroxidation and PPAR-δ in amplifying glucose-stimulated insulin secretion. Diabetes 2011; 60:2830-42. [PMID: 21896929 PMCID: PMC3198069 DOI: 10.2337/db11-0347] [Citation(s) in RCA: 270] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Previous studies show that polyunsaturated fatty acids (PUFAs) increase the insulin secretory capacity of pancreatic β-cells. We aimed at identifying PUFA-derived mediators and their cellular targets that are involved in the amplification of insulin release from β-cells preexposed to high glucose levels. RESEARCH DESIGN AND METHODS The content of fatty acids in phospholipids of INS-1E β-cells was determined by lipidomics analysis. High-performance liquid chromatography was used to identify peroxidation products in β-cell cultures. Static and dynamic glucose-stimulated insulin secretion (GSIS) assays were performed on isolated rat islets and/or INS-1E cells. The function of peroxisome proliferator-activated receptor-δ (PPAR-δ) in regulating insulin secretion was investigated using pharmacological agents and gene expression manipulations. RESULTS High glucose activated cPLA(2) and, subsequently, the hydrolysis of arachidonic and linoleic acid (AA and LA, respectively) from phospholipids in INS-1E cells. Glucose also increased the level of reactive oxygen species, which promoted the peroxidation of these PUFAs to generate 4-hydroxy-2E-nonenal (4-HNE). The latter mimicked the GSIS-amplifying effect of high glucose preexposure and of the PPAR-δ agonist GW501516 in INS-1E cells and isolated rat islets. These effects were blocked with GSK0660, a selective PPAR-δ antagonist, and the antioxidant N-acetylcysteine or by silencing PPAR-δ expression. High glucose, 4-HNE, and GW501516 also induced luciferase expression in a PPAR-δ-mediated transactivation assay. Cytotoxic effects of 4-HNE were observed only above the physiologically effective concentration range. CONCLUSIONS Elevated glucose levels augment the release of AA and LA from phospholipids and their peroxidation to 4-HNE in β-cells. This molecule is an endogenous ligand for PPAR-δ, which amplifies insulin secretion in β-cells.
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Affiliation(s)
- Guy Cohen
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Institute for Drug Research, Hebrew University, Jerusalem, Israel
| | - Yael Riahi
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Institute for Drug Research, Hebrew University, Jerusalem, Israel
| | - Ofer Shamni
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Institute for Drug Research, Hebrew University, Jerusalem, Israel
| | - Michel Guichardant
- CarMeN Laboratory, Lyon University, INSA de Lyon, INSERM U1060, Université de Lyon-1, Villeurbanne, France
| | | | - Carla Ferreri
- ISOF-BioFreeRadicals, Consiglio Nazionale delle Ricerche, Bologna, Italy
| | - Nurit Kaiser
- Endocrinology and Metabolism Service, Department of Medicine, Hadassah–Hebrew University Medical Center, Jerusalem, Israel
| | - Shlomo Sasson
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Institute for Drug Research, Hebrew University, Jerusalem, Israel
- Corresponding author: Shlomo Sasson,
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NO-Donating NSAIDs, PPARdelta, and Cancer: Does PPARdelta Contribute to Colon Carcinogenesis? PPAR Res 2011; 2008:919572. [PMID: 18528523 PMCID: PMC2408682 DOI: 10.1155/2008/919572] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2008] [Revised: 04/25/2008] [Accepted: 05/06/2008] [Indexed: 12/30/2022] Open
Abstract
The chemopreventive NO-donating NSAIDs (NO-NSAIDs; NSAIDs with an NO-releasing moiety) modulate PPARδ and offer the opportunity to revisit the controversial role of PPARδ in carcinogenesis (several papers report that PPARδ either promotes or inhibits cancer). This review summarizes the pharmacology of NO-NSAIDs, PPARδ cancer biology, and the relationship between the two. In particular, a study of the chemopreventive effect of two isomers of NO-aspirin on intestinal neoplasia in Min mice showed that, compared to wild-type controls, PPARδ is overexpressed in the intestinal mucosa of Min mice; PPARδ responds to
m- and p-NO-ASA proportionally to their antitumor effect (p- > m-). This effect is accompanied by the induction of epithelial cell death, which correlates with the antineoplastic effect of NO-aspirin; and NO-aspirin's effect on PPARδ is specific (no changes in PPARα or PPARγ). Although these data support the notion that PPARδ promotes intestinal carcinogenesis and its inhibition could be therapeutically useful, more work is needed before a firm conclusion is reached.
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Peroxisome proliferator-activated receptors and progression of colorectal cancer. PPAR Res 2011; 2008:931074. [PMID: 18551185 PMCID: PMC2422873 DOI: 10.1155/2008/931074] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Accepted: 04/29/2008] [Indexed: 12/18/2022] Open
Abstract
The peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily. These receptors are also ligand-dependent transcription factors responsible for the regulation of cellular events that range from glucose and lipid homeostases to cell differentiation and apoptosis. The importance of these receptors in lipid homeostasis and energy balance is well established. In addition to these metabolic and anti-inflammatory properties, emerging evidence indicates that PPARs can function as either tumor suppressors or accelerators, suggesting that these receptors are potential candidates as drug targets for cancer prevention and treatment. However, conflicting results have emerged regarding the role of PPARs on colon carcinogenesis. Therefore, further investigation is warranted prior to considering modulation of PPARs as an efficacious therapy for colorectal cancer chemoprevention and treatment.
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Omega-3 Fatty Acids and PPARgamma in Cancer. PPAR Res 2011; 2008:358052. [PMID: 18769551 PMCID: PMC2526161 DOI: 10.1155/2008/358052] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 05/30/2008] [Accepted: 06/24/2008] [Indexed: 01/25/2023] Open
Abstract
Omega-3 (or n-3) polyunsaturated fatty acids (PUFAs) and their metabolites are natural ligands for peroxisome proliferator receptor activator (PPAR)gamma and, due to the effects of PPARgamma on cell proliferation, survival, and differentiation, are potential anticancer agents. Dietary intake of omega-3 PUFAs has been associated with a reduced risk of certain cancers in human populations and in animal models. In vitro studies have shown that omega-3 PUFAs inhibit cell proliferation and induce apoptosis in cancer cells through various pathways but one of which involves PPARgamma activation. The differential activation of PPARgamma and PPARgamma-regulated genes by specific dietary fatty acids may be central to their distinct roles in cancer. This review summarizes studies relating PUFAs to PPARgamma and cancer and offers a new paradigm relating an n-3 PUFA through PPARgamma to the expression of the cell surface proteoglycan, syndecan-1, and to the death of cancer cells.
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The Role of PPAR Ligands in Controlling Growth-Related Gene Expression and their Interaction with Lipoperoxidation Products. PPAR Res 2011; 2008:524671. [PMID: 18615196 PMCID: PMC2443425 DOI: 10.1155/2008/524671] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Accepted: 06/05/2008] [Indexed: 11/18/2022] Open
Abstract
Peroxisome proliferators-activated receptors (PPARs) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily. The three PPAR isoforms (α, γ and β/δ) have been found to play a pleiotropic role in cell fat metabolism. Furthermore, in recent years, evidence has been found regarding the antiproliferative, proapoptotic, and differentiation-promoting activities displayed by PPAR ligands, particularly by PPARγ ligands. PPAR ligands affect the expression of different growth-related genes through both PPAR-dependent and PPAR-independent mechanisms. Moreover, an interaction between PPAR ligands and other molecules which strengthen the effects of PPAR ligands has been described. Here we review the action of PPAR on the control of gene expression with particular regard to the effect of PPAR ligands on the expression of genes involved in the regulation of cell-cycle, differentiation, and apoptosis. Moreover, the interaction between PPAR ligands and 4-hydroxynonenal (HNE), the major product of the lipid peroxidation, has been reviewed.
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Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily. PPARalpha is mainly expressed in the liver, where it activates fatty acid catabolism. PPARalpha activators have been used to treat dyslipidemia, causing a reduction in plasma triglyceride and elevation of high-density lipoprotein cholesterol. PPARdelta is expressed ubiquitously and is implicated in fatty acid oxidation and keratinocyte differentiation. PPARdelta activators have been proposed for the treatment of metabolic disease. PPARgamma2 is expressed exclusively in adipose tissue and plays a pivotal role in adipocyte differentiation. PPARgamma is involved in glucose metabolism through the improvement of insulin sensitivity and represents a potential therapeutic target of type 2 diabetes. Thus PPARs are molecular targets for the development of drugs treating metabolic syndrome. However, PPARs also play a role in the regulation of cancer cell growth. Here, we review the function of PPARs in tumor growth.
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Pink RC, Bailey TA, Iputo JE, Sammon AM, Woodman AC, Carter DRF. Molecular basis for maize as a risk factor for esophageal cancer in a South African population via a prostaglandin E2 positive feedback mechanism. Nutr Cancer 2011; 63:714-21. [PMID: 21667399 DOI: 10.1080/01635581.2011.570893] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The incidence of squamous cancer of the esophagus varies up to a hundredfold in different regions of the world. In Transkei, South Africa, a particularly high incidence of the disease is observed. We have previously proposed an association between a maize-rich diet and elevated levels of intragastric prostaglandin E2 production (PGE(2)). Here we investigate the molecular mechanisms by which a high-maize diet could lead to increased incidence of squamous cancer of the esophagus. We confirm that levels of PGE(2) are high (606.8 pg/ml) in the gastric fluid of individuals from Transkei. We also show that treatment of esophageal cells with linoleic acid, which is found at high levels in maize and is a precursor to PGE(2), leads to increased cell proliferation. Similarly, treatment of cells with PGE(2) or with gastric fluid from Transkeians also leads to increased proliferation. Our data suggest that the high levels of PGE(2) associated with a maize-rich diet stimulate cell division and induce the enzyme COX 2, resulting in a positive feedback mechanism that predisposes the esophagus to carcinoma.
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Affiliation(s)
- Ryan C Pink
- Cranfield Health, Cranfield University, Cranfield, Bedfordshire, United Kingdom.
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Wang D, DuBois RN. Therapeutic potential of peroxisome proliferator-activated receptors in chronic inflammation and colorectal cancer. Gastroenterol Clin North Am 2010; 39:697-707. [PMID: 20951925 PMCID: PMC2957674 DOI: 10.1016/j.gtc.2010.08.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Peroxisome proliferatoreactivated receptors (PPARs) are members of the nuclear hormone receptor superfamily and have been implicated in a variety of physiologic and pathologic processes, such as nutrient metabolism, energy homeostasis, inflammation, and cancer. This article highlights breakthroughs in our understanding of the potential roles of PPARs in inflammatory bowel disease and colorectal cancer. PPARs might hold the key to some of the questions that are pertinent to the pathophysiology of inflammatory diseases and colorectal cancer and could possibly serve as drug targets for new antiinflammatory therapeutic and anticancer agents.
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Affiliation(s)
- Dingzhi Wang
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009
| | - Raymond N. DuBois
- Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009,Correspondence to: Raymond N. DuBois, M.D., Ph. D. The University of Texas MD Anderson Cancer Center Unit 118; 1515 Holcombe Blvd. Houston, TX 77030-4009 Phone: 713-745-4495 FAX: 713-745-1812
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Sergeeva MG, Aleshin SE, Grabeklis S, Reiser G. PPAR activation has dichotomous control on the expression levels of cytosolic and secretory phospholipase A2 in astrocytes; inhibition in naïve, untreated cells and enhancement in LPS-stimulated cells. J Neurochem 2010; 115:399-410. [PMID: 20670373 DOI: 10.1111/j.1471-4159.2010.06931.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Despite the importance of cytosolic phospholipase A(2) type IVA (cPLA(2)) and secretory PLA(2) (sPLA(2)) in physiological and pathological responses of astrocytes in inflammatory conditions, the regulation of the expression of these genes is still unclear. Both genes have peroxisome proliferator-activated receptors (PPAR) binding sites in their promoters. The role of synthetic PPAR agonists in the regulation of gene expression in naïve and lipopolysaccharide (LPS)-stimulated rat astrocytes in culture was investigated. Exposure to LPS resulted in a time-dependent, fourfold transient increase of sPLA(2) expression, with maximum at 4 h; cPLA(2) expression was notably increased after 16-h LPS stimulation. Using selective PPARα, PPARβ/δ, and PPARγ agonists, we found that expression of both cPLA(2) and sPLA(2) is under PPAR control, but with different isotypes sensitivity. In naïve astrocytes, all three PPAR agonists significantly suppressed the expression of sPLA(2), while only PPARα and PPARγ activation suppressed cPLA(2) expression. Astonishingly, simultaneous addition of LPS with PPAR agonists evoked the opposite effect. All three PPAR agonists induced potentiation of cPLA(2) expression level. Potentiation of sPLA(2) expression was induced only by simultaneous addition of LPS with PPARγ agonist. By knockdown of PPARα, PPARβ/δ, and PPARγ, we confirmed the involvement of PPAR-dependent pathways. The important novelty of our findings is that both sPLA(2) and cPLA(2) are under dichotomous control of PPARs: suppression in naïve control cells, but induction in LPS-stimulated astrocytes.
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Affiliation(s)
- Marina G Sergeeva
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
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Mining mammalian transcript data for functional long non-coding RNAs. PLoS One 2010; 5:e10316. [PMID: 20428234 PMCID: PMC2859052 DOI: 10.1371/journal.pone.0010316] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 03/30/2010] [Indexed: 12/11/2022] Open
Abstract
Background The role of long non-coding RNAs (lncRNAs) in controlling gene expression has garnered increased interest in recent years. Sequencing projects, such as Fantom3 for mouse and H-InvDB for human, have generated abundant data on transcribed components of mammalian cells, the majority of which appear not to be protein-coding. However, much of the non-protein-coding transcriptome could merely be a consequence of ‘transcription noise’. It is therefore essential to use bioinformatic approaches to identify the likely functional candidates in a high throughput manner. Principal Findings We derived a scheme for classifying and annotating likely functional lncRNAs in mammals. Using the available experimental full-length cDNA data sets for human and mouse, we identified 78 lncRNAs that are either syntenically conserved between human and mouse, or that originate from the same protein-coding genes. Of these, 11 have significant sequence homology. We found that these lncRNAs exhibit: (i) patterns of codon substitution typical of non-coding transcripts; (ii) preservation of sequences in distant mammals such as dog and cow, (iii) significant sequence conservation relative to their corresponding flanking regions (in 50% cases, flanking regions do not have homology at all; and in the remaining, the degree of conservation is significantly less); (iv) existence mostly as single-exon forms (8/11); and, (v) presence of conserved and stable secondary structure motifs within them. We further identified orthologous protein-coding genes that are contributing to the pool of lncRNAs; of which, genes implicated in carcinogenesis are significantly over-represented. Conclusion Our comparative mammalian genomics approach coupled with evolutionary analysis identified a small population of conserved long non-protein-coding RNAs (lncRNAs) that are potentially functional across Mammalia. Additionally, our analysis indicates that amongst the orthologous protein-coding genes that produce lncRNAs, those implicated in cancer pathogenesis are significantly over-represented, suggesting that these lncRNAs could play an important role in cancer pathomechanisms.
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Röhrl C, Kaindl U, Koneczny I, Hudec X, Baron DM, König JS, Marian B. Peroxisome-proliferator-activated receptors γ and β/δ mediate vascular endothelial growth factor production in colorectal tumor cells. J Cancer Res Clin Oncol 2010; 137:29-39. [PMID: 20221637 DOI: 10.1007/s00432-010-0856-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Accepted: 02/19/2010] [Indexed: 02/06/2023]
Abstract
BACKGROUND Peroxisome-proliferator-activated receptors (PPARs) are nuclear receptors for fatty acids and their derivatives. PPAR subtypes PPARγ and PPARβ/δ are suspected to modulate cancer development in the colon, but their exact role is still discussed controversially. METHODS The present study investigated the impact of PPARγ and PPARβ/δ on vascular endothelial growth factor (VEGF) and cyclooxygenase 2 (COX-2) expressions induced by synthetic and physiological agonists in the colorectal tumor cell lines SW480 and HT29 using reporter gene assays, qRT-PCR and ELISA. RESULTS Activation of both PPARγ and PPARβ/δ induced expression of VEGF mRNA and protein in a PPAR-dependent way. The PPARγ agonists ciglitazone and PGJ(2) were the most effective inducers with up to ninefold and threefold increases in VEGF mRNA in SW480 and HT29 cultures, respectively. VEGF secretion was doubled in both cell lines. The PPARβ/δ agonists GW501516 and PGI(2) caused stimulations of only 1.5-fold in both cell lines. In addition, all PPAR agonists induced COX-2 mRNA and secretion of the COX-2 product PGE(2) in HT29 cells. However, this effect was not blocked by knock-down of PPAR expression nor was it essential for VEGF expression as shown by the lack of effect of the COX-2 inhibitor SC236. CONCLUSION In summary, our results identify both PPARγ and PPARβ/δ as an alternative COX-independent mechanism of VEGF induction in colorectal tumor cells.
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Affiliation(s)
- Clemens Röhrl
- Department of Medicine 1, Clinic for Internal Medicine I, Institute of Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria
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Higa R, White V, Martinez N, Kurtz M, Capobianco E, Jawerbaum A. Safflower and olive oil dietary treatments rescue aberrant embryonic arachidonic acid and nitric oxide metabolism and prevent diabetic embryopathy in rats. Mol Hum Reprod 2010; 16:286-95. [DOI: 10.1093/molehr/gap109] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kwak H, Hwang I, Kim JH, Kim MY, Yang JS, Jeong S. Modulation of transcription by the peroxisome proliferator-activated receptor delta--binding RNA aptamer in colon cancer cells. Mol Cancer Ther 2009; 8:2664-73. [PMID: 19723884 DOI: 10.1158/1535-7163.mct-09-0214] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Peroxisome proliferator-activated receptor delta (PPAR-delta), one of three PPAR subtypes, is a lipid-sensing nuclear receptor that has been implicated in multiple processes, including inflammation and cancer. To directly establish the role of PPAR-delta in colon cancer development and progression, we selected high-affinity RNA aptamers and expressed them in several colon cancer cell lines. Nuclear-expressed aptamers efficiently inhibited PPAR-delta-dependent transcription from a synthetic peroxisome proliferator response element-driven luciferase reporter. PPAR-delta-specific aptamers suppressed transcription from natural promoters of vascular endothelial cell growth factor-A and cyclooxygenase-2. Moreover, vascular endothelial cell growth factor-A and cyclooxygenase-2 mRNA levels were significantly reduced by the PPAR-delta-specific aptamers in colon cancer cells. Most significantly, HCT116 colon cancer cells with high-level expression of PPAR-delta-specific aptamers exhibited a striking loss of tumorigenic potential. Further study on these RNA aptamers could provide an opportunity to modulate PPAR-delta-mediated colon cancer development and progression. Taken together, our results establish an important role for PPAR-delta in transcription of tumor-promoting genes, which can be specifically modulated by high-affinity RNA intramers in colon cancer cells. The RNA intramers may be further developed as specific inhibitors for cancer therapeutic strategies.
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Affiliation(s)
- Hoyun Kwak
- Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin-si, Gyeonggi-do 448-701, Republic of Korea
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Peters JM, Gonzalez FJ. Sorting out the functional role(s) of peroxisome proliferator-activated receptor-beta/delta (PPARbeta/delta) in cell proliferation and cancer. Biochim Biophys Acta Rev Cancer 2009; 1796:230-41. [PMID: 19505534 DOI: 10.1016/j.bbcan.2009.06.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 06/01/2009] [Accepted: 06/02/2009] [Indexed: 12/19/2022]
Abstract
Peroxisome proliferator-activated receptor-beta/delta (PPARbeta/delta) has many beneficial physiological functions ranging from enhancing fatty acid catabolism, improving insulin sensitivity, inhibiting inflammation and increasing oxidative myofibers allowing for improved athletic performance. Thus, given the potential for targeting PPARbeta/delta for the prevention and/or treatment of diseases including diabetes, dyslipidemias, metabolic syndrome and cancer, it is critical to clarify the functional role of PPARbeta/delta in cell proliferation and associated disorders such as cancer. However, there is considerable controversy whether PPARbeta/delta stimulates or inhibits cell proliferation. This review summarizes the literature describing the influence of PPARbeta/delta on cell proliferation, with an emphasis toward dissecting the data that give rise to opposing hypotheses. Suggestions are offered to standardize measurements associated with these studies so that interlaboratory comparisons can be accurately assessed.
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Affiliation(s)
- Jeffrey M Peters
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA 16802, USA.
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Zuo X, Peng Z, Moussalli MJ, Morris JS, Broaddus RR, Fischer SM, Shureiqi I. Targeted genetic disruption of peroxisome proliferator-activated receptor-delta and colonic tumorigenesis. J Natl Cancer Inst 2009; 101:762-7. [PMID: 19436036 DOI: 10.1093/jnci/djp078] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Peroxisome proliferator-activated receptor-delta (PPAR-delta) is overexpressed in human colon cancer, but its contribution to colonic tumorigenesis is controversial. We generated a mouse model in which PPAR-delta was genetically disrupted in colonic epithelial cells by targeted deletion of exon 4. Elimination of colon-specific PPAR-delta expression was confirmed by real-time reverse transcription-polymerase chain reaction (real-time RT-PCR), immunoblotting, and activity assays. Mice with and without targeted PPAR-delta genetic disruption (10-11 mice per group) were tested for incidence of azoxymethane-induced colon tumors. The effects of targeted PPAR-delta deletion on vascular endothelial growth factor expression were determined by real-time RT-PCR. Targeted PPAR-delta genetic disruption inhibited colonic carcinogenesis: Mice with PPAR-delta((-/-)) colons developed 98.5% fewer tumors than wild-type mice (PPAR-delta((-/-)) vs wild-type, mean = 0.1 tumors per mouse vs 6.6 tumors per mouse, difference = 6.5 tumors per mouse, 95% confidence interval = 4.9 to 8.0 tumors per mouse, P < .001, two-sided test). Increased expression of vascular endothelial growth factor in colon tumors vs normal colon was suppressed by loss of PPAR-delta expression. These findings indicate that PPAR-delta has a crucial role in promoting colonic tumorigenesis.
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Affiliation(s)
- Xiangsheng Zuo
- Department of Clinical Cancer Prevention, Unit 1360, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA
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The PPARδ ligand GW501516 reduces growth but not apoptosis in mouse inner medullary collecting duct cells. PPAR Res 2009; 2009:706283. [PMID: 19266055 PMCID: PMC2651001 DOI: 10.1155/2009/706283] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 12/12/2008] [Accepted: 01/05/2009] [Indexed: 11/18/2022] Open
Abstract
The collecting duct (CD) expresses considerable amounts of PPARδ. While its role is unknown in the CD, in other renal cells it has been shown to regulate both growth and apoptosis. We thus hypothesized that PPARδ reduces apoptotic responses and stimulates cell
growth in the mouse CD, and examined the effect of GW501516, a synthetic PPARδ ligand, on these responses in mouse IMCD-K2 cells. High doses of GW501516 decreased both DNA and protein synthesis in these cells by 80%, but had no overall effect on cell viability. Although anisomycin treatment resulted in an increase of caspase-3 levels of about 2.59-fold of control, GW501516 did not affect anisomycin-induced changes in active caspase-3 levels. These results show that a
PPARδ ligand inhibits growth but does not affect anisomycin-apoptosis in a mouse IMCD cell line. This could have therapeutic implications for renal diseases associated with increased CD growth responses.
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Lin CC, Lin WN, Wang WJ, Sun CC, Tung WH, Wang HH, Yang CM. Functional coupling expression of COX-2 and cPLA2 induced by ATP in rat vascular smooth muscle cells: role of ERK1/2, p38 MAPK, and NF-kappaB. Cardiovasc Res 2009; 82:522-31. [PMID: 19233864 DOI: 10.1093/cvr/cvp069] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Vascular smooth muscle cells (VSMCs) that function as synthetic units play important roles in inflammatory diseases such as atherosclerosis and angiogenesis. As extracellular nucleotides such as ATP have been shown to act via activation of P(2) purinoceptors implicated in various inflammatory diseases, we hypothesized that extracellular nucleotides contribute to vascular diseases via upregulated expression of inflammatory proteins, such as cyclooxygenase (COX-2) and cytosolic phospholipase A2 (cPLA2) in VSMCs. METHODS AND RESULTS Western blotting, promoter assay, RT-PCR, and PGE2 immunoassay revealed that ATPgammaS induced expression of COX-2 and prostaglandin (PGE2) synthesis through the activation of p42/p44 MAPK (mitogen-activated protein kinase), p38 MAPK, and nuclear factor-kappaB (NF-kappaB). These responses were attenuated by inhibitors of MAPK/ERK kinase (MEK1/2; U0126), p38 MAPK (SB202190), and NF-kappaB (helenalin), or by tranfection with dominant negative mutants of p42, p38, IkappaB kinase (IKK)alpha, and IKKbeta. Furthermore, the ATPgammaS-stimulated translocation of NF-kappaB into the nucleus and degradation of IkappaBalpha was blocked by U0126 and helenalin. In addition, the ATPgammaS-stimulated cPLA2 expression was inhibited by U0126, SB202190, helenalin, celecoxib (a selective COX-2 inhibitor), and PGE2 receptor antagonists (AH6809, GW627368X, and SC-19220). However, the inhibitory effect of celecoxib on cPLA2 expression was reversed by addition of exogenous PGE2. CONCLUSION Our results suggest that in VSMCs, activation of p42/p44 MAPK, p38 MAPK, and NF-kappaB is essential for ATPgammaS-induced COX-2 expression and PGE2 synthesis. Newly synthesized PGE2 was observed to act as an autocrine signal contributing to cPLA2 expression, which may be implicated in inflammatory responses. Collectively, our findings provide insights into the correlation between COX-2 and cPLA2 expression in ATPgammaS-stimulated VSMCs with similar molecular mechanisms and functional coupling to amplify the occurrence of vessel disease-related vascular inflammation.
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Affiliation(s)
- Chih-Chung Lin
- Department of Anesthetics, Chang Gung University, Tao-Yuan, Taiwan, Republic of China
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Han C, Lim K, Xu L, Li G, Wu T. Regulation of Wnt/beta-catenin pathway by cPLA2alpha and PPARdelta. J Cell Biochem 2009; 105:534-45. [PMID: 18636547 DOI: 10.1002/jcb.21852] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cytosolic phospholipase A(2)alpha (cPLA(2)alpha) is a rate-limiting key enzyme that releases arachidonic acid (AA) from membrane phospholipid for the production of biologically active lipid mediators including prostaglandins, leukotrienes and platelet-activating factor. cPLA(2)alpha is translocated to nuclear envelope in response to intracellular calcium increase and the enzyme is also present inside the cell nucleus; however, the biological function of cPLA(2)alpha in the nucleus remains unknown. Here we show a novel role of cPLA(2)alpha for activation of peroxisome proliferator-activated receptor-delta (PPARdelta) and beta-catenin in the nuclei. Overexpression of cPLA(2)alpha in human cholangiocarcinoma cells induced the binding of PPARdelta to beta-catenin and increased their association with the TCF/LEF response element. These effects are inhibited by the cPLA(2)alpha siRNA and inhibitors as well as by siRNA knockdown of PPARdelta. Overexpression of PPARdelta or treatment with the selective PPARdelta ligand, GW501516, also increased beta-catenin binding to TCF/LEF response element and increased its reporter activity. Addition of AA and GW501516 to nuclear extracts induced a comparable degree of beta-catenin binding to TCF/LEF response element. Furthermore, cPLA(2)alpha protein is present in the PPARdelta and beta-catenin binding complex. Thus the close proximity between cPLA(2)alpha and PPARdelta provides a unique advantage for their efficient functional coupling in the nucleus, where AA produced by cPLA(2)alpha becomes immediately available for PPARdelta binding and subsequent beta-catenin activation. These results depict a novel interaction linking cPLA(2)alpha, PPARdelta and Wnt/beta-catenin signaling pathways and provide insight for further understanding the roles of these key molecules in human cells and diseases.
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Affiliation(s)
- Chang Han
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
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Michalik L, Wahli W. PPARs Mediate Lipid Signaling in Inflammation and Cancer. PPAR Res 2008; 2008:134059. [PMID: 19125181 PMCID: PMC2606065 DOI: 10.1155/2008/134059] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Accepted: 09/17/2008] [Indexed: 02/06/2023] Open
Abstract
Lipid mediators can trigger physiological responses by activating nuclear hormone receptors, such as the peroxisome proliferator-activated receptors (PPARs). PPARs, in turn, control the expression of networks of genes encoding proteins involved in all aspects of lipid metabolism. In addition, PPARs are tumor growth modifiers, via the regulation of cancer cell apoptosis, proliferation, and differentiation, and through their action on the tumor cell environment, namely, angiogenesis, inflammation, and immune cell functions. Epidemiological studies have established that tumor progression may be exacerbated by chronic inflammation. Here, we describe the production of the lipids that act as activators of PPARs, and we review the roles of these receptors in inflammation and cancer. Finally, we consider emerging strategies for therapeutic intervention.
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Affiliation(s)
- Liliane Michalik
- Center for Integrative Genomics, National Research Center Frontiers in Genetics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Walter Wahli
- Center for Integrative Genomics, National Research Center Frontiers in Genetics, University of Lausanne, 1015 Lausanne, Switzerland
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Ishikawa TO, Jain N, Herschman HR. Feedback regulation of cyclooxygenase-2 transcription ex vivo and in vivo. Biochem Biophys Res Commun 2008; 378:534-8. [PMID: 19061862 DOI: 10.1016/j.bbrc.2008.11.099] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 11/17/2008] [Indexed: 10/21/2022]
Abstract
Cyclooxygenase-2 (COX-2) is a rate-limiting enzyme for prostaglandin biosynthesis. Its inducible expression is regulated by complex pathways. To monitor Cox-2 transcriptional activity in vivo, we generated a knock-in mouse expressing a firefly luciferase reporter. In this study we examined, by comparing luciferase activity of Cox-2(luc/+) and Cox-2(luc/-) cells and mice, effects of prostanoid products on Cox-2 promoter transcriptional activation. In peritoneal macrophages, luciferase induction by LPS in Cox-2(luc/-) cells was less than that of Cox-2(luc/+) cells. However, in the presence of PGE(2), induction was comparable, suggesting positive Cox-2 feedback regulation by PGE(2) occurs for macrophages. In contrast, feedback modulation was not observed in TPA-induced Cox-2(luc/+) and Cox-2(luc/-) mouse embryonic fibroblasts (MEFs). Using non-invasive in vivo imaging, we observed negative feedback regulation of Cox-2 expression during paw inflammation in living mice. Our results suggest Cox-2 expression is regulated by cell type specific feedback mechanisms, both in cultured cells and in living animals.
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Affiliation(s)
- Tomo-O Ishikawa
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, 341 Boyer Hall, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
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Zeng L, Geng Y, Tretiakova M, Yu X, Sicinski P, Kroll TG. Peroxisome proliferator-activated receptor-delta induces cell proliferation by a cyclin E1-dependent mechanism and is up-regulated in thyroid tumors. Cancer Res 2008; 68:6578-86. [PMID: 18701481 DOI: 10.1158/0008-5472.can-08-0855] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are lipid-sensing nuclear receptors that have been implicated in multiple physiologic processes including cancer. Here, we determine that PPARdelta induces cell proliferation through a novel cyclin E1-dependent mechanism and is up-regulated in many human thyroid tumors. The expression of PPARdelta was induced coordinately with proliferation in primary human thyroid cells by the activation of serum, thyroid-stimulating hormone/cyclic AMP, or epidermal growth factor/mitogen-activated protein kinase mitogenic signaling pathways. Engineered overexpression of PPARdelta increased thyroid cell number, the incorporation of bromodeoxyuridine, and the phosphorylation of retinoblastoma protein by 40% to 45% in just 2 days, one usual cell population doubling. The synthetic PPARdelta agonist GW501516 augmented these PPARdelta proliferation effects in a dose-dependent manner. Overexpression of PPARdelta increased cyclin E1 protein by 9-fold, whereas knockdown of PPARdelta by small inhibitory RNA reduced both cyclin E1 protein and cell proliferation by 2-fold. Induction of proliferation by PPARdelta was abrogated by knockdown of cyclin E1 by small inhibitory RNA in primary thyroid cells and by knockout of cyclin E1 in mouse embryo fibroblasts, confirming a cyclin E1 dependence for this PPARdelta pathway. In addition, the mean expression of native PPARdelta was increased by 2-fold to 5-fold (P < 0.0001) and correlated with that of the in situ proliferation marker Ki67 (R = 0.8571; P = 0.02381) in six different classes of benign and malignant human thyroid tumors. Our experiments identify a PPARdelta mechanism that induces cell proliferation through cyclin E1 and is regulated by growth factor and lipid signals. The data argue for systematic investigation of PPARdelta antagonists as antineoplastic agents and implicate altered PPARdelta-cyclin E1 signaling in thyroid and other carcinomas.
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Affiliation(s)
- Lingchun Zeng
- Department of Pathology, University of Chicago School of Medicine, University of Chicago Cancer Research Center, Chicago, Illinois, USA
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Hooks SB, Cummings BS. Role of Ca2+-independent phospholipase A2 in cell growth and signaling. Biochem Pharmacol 2008; 76:1059-67. [PMID: 18775417 DOI: 10.1016/j.bcp.2008.07.044] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 07/15/2008] [Accepted: 07/15/2008] [Indexed: 01/25/2023]
Abstract
Phospholipase A(2) (PLA(2)) are esterases that cleave glycerophospholipids to release fatty acids and lysophospholipids. Several studies demonstrate that PLA(2) regulate growth and signaling in several cell types. However, few of these studies have focused on Ca2+-independent phospholipase A(2) (iPLA(2) or Group VI PLA(2)). This class of PLA(2) was originally suggested to mediate phospholipid remodeling in several cell types including macrophages. As such, it was labeled as a housekeeping protein and thought not to play as significant of roles in cell growth as its older counterparts cytosolic PLA(2) (cPLA(2) or Group IV PLA(2)) and secretory PLA(2) (sPLA(2) or Groups I-III, V and IX-XIV PLA(2)). However, several recent studies demonstrate that iPLA(2) mediate cell growth, and do so by participating in signal transduction pathways that include epidermal growth factor receptors (EGFR), mitogen activated protein kinases (MAPK), mdm2, and even the tumor suppressor protein p53 and the cell cycle regulator p21. The exact mechanism by which iPLA(2) mediates these pathways are not known, but likely involve the generation of lipid signals such as arachidonic acid, lysophosphatidic acid (LPA) and lysophosphocholines (LPC). This review discusses the role of iPLA(2) in cell growth with special emphasis placed on their role in cell signaling. The putative lipid signals involved are also discussed.
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Affiliation(s)
- Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602, USA
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Shan W, Palkar PS, Murray IA, McDevitt EI, Kennett MJ, Kang BH, Isom HC, Perdew GH, Gonzalez FJ, Peters JM. Ligand activation of peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) attenuates carbon tetrachloride hepatotoxicity by downregulating proinflammatory gene expression. Toxicol Sci 2008; 105:418-28. [PMID: 18622026 DOI: 10.1093/toxsci/kfn142] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR) beta/delta-null mice exhibit exacerbated hepatotoxicity in response to administration of carbon tetrachloride (CCl(4)). To determine whether ligand activation of the receptor protects against chemical toxicity in the liver, wild-type and PPARbeta/delta-null mice were administered CCl(4) with or without coadministration of the highly specific PPARbeta/delta ligand GW0742. Biomarkers of liver toxicity, including serum alanine aminotransferase (ALT) and hepatic tumor necrosis factor (TNF) alpha mRNA, were significantly higher in CCl(4)-treated PPARbeta/delta-null mice compared to wild-type mice. Hepatic expression of TNF-like weak inducer of apoptosis receptor (TWEAKr) and S100 calcium-binding protein A6 (S100A6/calcyclin), genes involved in nuclear factor kappa B signaling, was higher in the CCl(4)-treated PPARbeta/delta-null mice compared to wild-type mice. GW0742 treatment resulted in reduced serum ALT concentration and lower expression of CCl(4)-induced TNF-alpha, S100A6, monocyte chemoattractant protein-1 (MCP1), and TWEAKr in wild-type mice, and these effects were not observed in PPARbeta/delta-null mice. Expression of TNF-alpha was higher in PPARbeta/delta-null primary hepatocytes in response to interleukin-1beta treatment compared to wild-type hepatocytes, but GW0742 did not significantly modulate TNF-alpha expression in hepatocytes from either genotype. While PPARbeta/delta-null hepatic stellate exhibited higher rates of proliferation compared to wild-type cells, GW0742 did not affect alpha-smooth muscle actin expression in these cells. Combined, these findings demonstrate that ligand activation of PPARbeta/delta protects against chemically induced hepatotoxicity by downregulating expression of proinflammatory genes. Hepatocytes and hepatic stellate cells do not appear to directly mediate the inhibitory effects of ligand activation of PPARbeta/delta in liver, suggesting the involvement of paracrine and autocrine events mediated by hepatic cells.
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Affiliation(s)
- Weiwei Shan
- Department of Veterinary and Biomedical Sciences and The Center for Molecular Toxicology and Carcinogenesis, The Huck Institute of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Capobianco E, White V, Higa R, Martinez N, Jawerbaum A. Effects of natural ligands of PPAR on lipid metabolism in placental tissues from healthy and diabetic rats. Mol Hum Reprod 2008; 14:491-9. [DOI: 10.1093/molehr/gan039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Tsuji K, Mitsutake S, Yokose U, Sugiura M, Kohama T, Igarashi Y. Role of ceramide kinase in peroxisome proliferator-activated receptor beta-induced cell survival of mouse keratinocytes. FEBS J 2008; 275:3815-26. [PMID: 18565104 DOI: 10.1111/j.1742-4658.2008.06527.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ceramide (Cer) is known to be a lipid mediator in apoptosis and to have an important role in cell fate, via control of intracellular Cer levels. Recently, ceramide kinase (CerK) was identified as an enzyme that converts Cer to ceramide 1-phosphate (C1P). We examined potential functions of CerK in the regulation of keratinocyte survival, and the possible involvement of peroxisome proliferator-activated receptor beta (PPARbeta). PPARbeta is known to be a nuclear receptor acting as a ligand-inducible transcription factor and has been implicated in the control of keratinocyte survival. In the mouse keratinocyte cell line SP1, serum starvation induced cell death and the accumulation of intracellular Cer, an apoptotic event. However, apoptosis was inhibited by activation of PPARbeta. Interestingly, activation of PPARbeta enhanced the mRNA expression of CerK and CerK activity. Furthermore, the cell survival effect of PPARbeta was greatly diminished in keratinocytes isolated from CerK-null mice. Chromatin immunoprecipitation revealed that, in vivo, PPARbeta binds to the CerK gene via a sequence located in the first intron. Electrophoretic mobility-shift assays confirmed that PPARbeta associates with this sequence in vitro. These findings indicated that CerK gene expression was directly regulated by PPARbeta. In conclusion, our results demonstrate that PPARbeta-mediated upregulation of CerK gene expression is necessary for keratinocyte survival against serum starvation-induced apoptosis.
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Affiliation(s)
- Kiyomi Tsuji
- Laboratory of Biomembrane and Biofunctional Chemistry, Faculty of Advanced Life Sciences, Hokkaido University, Sapporo, Japan
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Pedchenko TV, Gonzalez AL, Wang D, DuBois RN, Massion PP. Peroxisome proliferator-activated receptor beta/delta expression and activation in lung cancer. Am J Respir Cell Mol Biol 2008; 39:689-96. [PMID: 18566335 DOI: 10.1165/rcmb.2007-0426oc] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) is a ligand-binding inducible transcriptional factor linked to carcinogenesis. Important functions of PPARbeta/delta were demonstrated in series of human epithelial cancers; however, its role in lung cancer remains controversial. We investigated the differential expression level and localization of PPARbeta/delta in tumors and adjacent normal lung tissue, and the effect of PPARbeta/delta activation on lung cancer cell proliferation and apoptosis. PPARbeta/delta was expressed in all studied human non-small cell lung cancers, and strong PPARbeta/delta immunoreactivity was observed in epithelial cells of more than 75% of studied lung tumors. PPARbeta/delta expression was consistently limited to the cancer cells in tumor tissue, while in adjacent normal lung tissue it was limited predominantly to the mononuclear cells. We found that ligand-binding activation of PPARbeta/delta stimulates cell proliferation (an effect that was blocked by a dominant-negative construct of PPARbeta/delta), stimulates anchorage-independent cell growth, and inhibits apoptosis in lung cancer cell lines. Importantly, the activation of PPARbeta/delta induces Akt phosphorylation correlated with up-regulation of PDK1, down-regulation of PTEN, and increased expression of Bcl-xL and COX-2. These findings indicate that PPARbeta/delta exerts proliferative and anti-apoptotic effects via PI3K/Akt1 and COX-2 pathways. In conclusion, PPARbeta/delta is strongly expressed in the majority of lung cancers, and its activation induces proliferative and survival response in non-small cell lung cancer.
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Affiliation(s)
- Tetyana V Pedchenko
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-6838, USA
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Abstract
Bowel diseases reveal the complex interplay of sensing and signalling pathways in maintaining healthy homeostasis of the intestine. Recent studies of the xenobiotic nuclear receptor, pregnane X receptor and the inflammatory mediator nuclear transcription factor kappaB (NF-kappaB) reveal a functional link between xenobiotic neutralization and inflammation and explain how certain xenobiotics can affect the immune response. Furthermore, another nuclear receptor, peroxisome proliferator-activated receptor gamma (PPAR gamma) has been shown to produce beneficial effects in experimental inflammatory bowel diseases by repression of NF-kappaB thereby reducing inflammation, whilst its close relative PPAR beta/delta appears at a central position in signalling pathways involved in the progression of colon cancer. Recently accumulated knowledge on the action of these nuclear receptors and NF-kappaB in intestinal homeostasis may provide the rationale for the development of innovative treatment strategies with selective receptor modulators.
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Affiliation(s)
- W Wahli
- Center for Integrative Genomics, National Research Center Frontiers in Genetics, University of Lausanne, Lausanne, Switzerland.
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Sun B, Zhang X, Talathi S, Cummings BS. Inhibition of Ca2+-Independent Phospholipase A2 Decreases Prostate Cancer Cell Growth by p53-Dependent and Independent Mechanisms. J Pharmacol Exp Ther 2008; 326:59-68. [DOI: 10.1124/jpet.108.138958] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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High-Glucose-Induced Prostaglandin E2and Peroxisome Proliferator-Activated Receptor δ Promote Mouse Embryonic Stem Cell Proliferation. Stem Cells 2008; 26:745-55. [DOI: 10.1634/stemcells.2007-0786] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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