Stimulation of Peroxisome Proliferator-Activated Receptor-Gamma (PPARγ) using Pioglitazone Decreases the Survival of Acute Promyelocytic Leukemia Cells through Up-Regulation of PTEN Expression

2020 ◽  
Vol 21 (1) ◽  
pp. 108-119
Author(s):  
Shadi Esmaeili ◽  
Ava Safaroghli-Azar ◽  
Atieh Pourbagheri-Sigaroodi ◽  
Sina Salari ◽  
Ahmad Gharehbaghian ◽  
...  

Background: The intertwining between cancer pathogenesis and aberrant expression of either oncogenes or tumor suppressor proteins ushered the cancer therapeutic approaches into a limitless road of modern therapies. For the nonce and among the plethora of promising anticancer agents, intense interest has focused on pioglitazone, a first in-class of Thiazolidinedione (TZD) drugs that is currently used to treat patients with diabetes. Objective: Intrigued by the overexpression of PPARγ in Acute Promylocytic Leukemia (APL), this study was designed to investigate the effects of pioglitazone in APL-derived NB4 cells. Methods: To assess the anti-leukemic effect of pioglitazone on myeloid leukemia cell lines, we used MTT and trypan blue assays. Given the higher expression level of PPARγ in NB4 cells, we then expanded our experiments on this cell line. To ascertain the molecular mechanism action of pioglitazone in APL-derived NB4 cells, we evaluated the expression levels of a large cohort of target genes responsible for the regulation of apoptosis, autophagy and cell proliferation. Afterward, to examine whether there is a correlation between PPARγ and the PI3K signaling pathway, the amount of Akt phosphorylation was evaluated using western blot analysis. Results: Our results showed that pioglitazone exerted its cytotoxic effect in wild-type PTEN-expressing NB4 cells, but not in leukemic K562 cells harboring mutant PTEN; suggesting that probably this member of TZD drugs induced its anti-leukemic effects through a PTEN-mediated manner. Moreover, we found that not only pioglitazone reduced the survival rate of NB4 through the induction of p21-mediated G1 arrest, also elevated the intracellular level of Reactive Oxygen Species (ROS) which was coupled with upregulated FOXO3a. Notably, this study proposed for the first time that the stimulation of autophagy as a result of the compensatory activation of PI3K pathway may act as a plausible mechanism through which the anti-leukemic effect of pioglitazone may be attenuated; suggestive of the application of either PI3K or autophagy inhibitors along with pioglitazone in APL. Conclusion: By suggesting a mechanistic pathway, the results of the present study shed more light on the favorable anti-leukemic effect of pioglitazone and suggest it as a promising drug that should be clinically investigated in APL patients.

2021 ◽  
Author(s):  
Chun Yang ◽  
Stéphane Croteau ◽  
Pierre Hardy

Abstract Background HDAC9 (histone deacetylase 9) belongs to the class IIa family of histone deacetylases. This enzyme can shuttle freely between the nucleus and cytoplasm and promotes tissue-specific transcriptional regulation by interacting with histone and non-histone substrates. HDAC9 plays an essential role in diverse physiological processes including cardiac muscle development, bone formation, adipocyte differentiation and innate immunity. HDAC9 inhibition or activation is therefore a promising avenue for therapeutic intervention in several diseases. HDAC9 overexpression is also common in cancer cells, where HDAC9 alters the expression and activity of numerous relevant proteins involved in carcinogenesis. Conclusions This review summarizes the most recent discoveries regarding HDAC9 as a crucial regulator of specific physiological systems and, more importantly, highlights the diverse spectrum of HDAC9-mediated posttranslational modifications and their contributions to cancer pathogenesis. HDAC9 is a potential novel therapeutic target, and the restoration of aberrant expression patterns observed among HDAC9 target genes and their related signaling pathways may provide opportunities to the design of novel anticancer therapeutic strategies.


PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Daniela P. Foti ◽  
Francesco Paonessa ◽  
Eusebio Chiefari ◽  
Antonio Brunetti

The insulin receptor (IR) plays a crucial role in mediating the metabolic and proliferative functions triggered by the peptide hormone insulin. There is considerable evidence that abnormalities in both IR expression and function may account for malignant transformation and tumour progression in some human neoplasias, including breast cancer. PPARγis a ligand-activated, nuclear hormone receptor implicated in many pleiotropic biological functions related to cell survival and proliferation. In the last decade, PPARγagonists—besides their known action and clinical use as insulin sensitizers—have proved to display a wide range of antineoplastic effects in cells and tissues expressing PPARγ, leading to intensive preclinical research in oncology. PPARγand activators affect tumours by different mechanisms, involving cell proliferation and differentiation, apoptosis, antiinflammatory, and antiangiogenic effects. We recently provided evidence that PPARγand agonists inhibit IR by non canonical, DNA-independent mechanisms affecting IR gene transcription. We conclude that IR may be considered a new PPARγ“target” gene, supporting a potential use of PPARγagonists as antiproliferative agents in selected neoplastic tissues that overexpress the IR.


2007 ◽  
Vol 293 (1) ◽  
pp. R70-R77 ◽  
Author(s):  
Sebastian Luci ◽  
Beatrice Giemsa ◽  
Holger Kluge ◽  
Klaus Eder

This study investigated the effect of clofibrate treatment on expression of target genes of peroxisome proliferator-activated receptor (PPAR)-α and various genes of the lipid metabolism in liver and adipose tissue of pigs. An experiment with 18 pigs was performed in which pigs were fed either a control diet or the same diet supplemented with 5 g clofibrate/kg for 28 days. Pigs treated with clofibrate had heavier livers, moderately increased mRNA concentrations of various PPAR-α target genes in liver and adipose tissue, a higher concentration of 3-hydroxybutyrate, and markedly lower concentrations of triglycerides and cholesterol in plasma and lipoproteins than control pigs ( P < 0.05). mRNA concentrations of sterol regulatory element-binding proteins (SREBP)-1 and -2, insulin-induced genes ( Insig) -1 and Insig-2, and the SREBP target genes acetyl-CoA carboxylase, 3-methyl-3-hydroxyglutaryl-CoA reductase, and low-density lipoprotein receptor in liver and adipose tissue and mRNA concentrations of apolipoproteins A-I, A-II, and C-III in the liver were not different between both groups of pigs. In conclusion, this study shows that clofibrate treatment activates PPAR-α in liver and adipose tissue and has a strong hypotriglyceridemic and hypocholesterolemic effect in pigs. The finding that mRNA concentrations of some proteins responsible for the hypolipidemic action of fibrates in humans were not altered suggests that there were certain differences in the mode of action compared with humans. It is also shown that PPAR-α activation by clofibrate does not affect hepatic expression of SREBP target genes involved in synthesis of triglycerides and cholesterol homeostasis in liver and adipose tissue of pigs.


2020 ◽  
Author(s):  
Joaquín Pérez-Schindler ◽  
Bastian Kohl ◽  
Konstantin Schneider-Heieck ◽  
Volkan Adak ◽  
Julien Delezie ◽  
...  

AbstractThe peroxisome-proliferator-activated receptor-γ coactivator-1α (PGC-1α) integrates environmental cues by controlling complex transcriptional networks in various metabolically active tissues. However, it is unclear how a transcriptional coregulator coordinates dynamic biological programs in response to multifaceted stimuli such as endurance training or fasting. Here, we discovered a central function of the poorly understood C-terminal domain (CTD) of PGC-1α to bind RNAs and assemble multi-protein complexes. Surprisingly, in addition to controlling the coupling of transcription and processing of target genes, RNA binding is indispensable for the recruitment of PGC-1α to chromatin into liquid-like nuclear condensates, which compartmentalize and regulate active transcription. These results demonstrate a hitherto unsuspected molecular mechanism by which complexity in the regulation of large transcriptional networks by PGC-1α is achieved. These findings are not only essential for the basic understanding of transcriptional coregulator-driven control of biological programs, but will also help to devise new strategies to modulate these processes in pathological contexts in which PGC-1α function is dysregulated, such as type 2 diabetes, cardiovascular diseases or skeletal muscle wasting.


Endocrinology ◽  
2008 ◽  
Vol 150 (3) ◽  
pp. 1225-1234 ◽  
Author(s):  
Shin-ichi Oka ◽  
Eiji Yoshihara ◽  
Akiko Bizen-Abe ◽  
Wenrui Liu ◽  
Mutsumi Watanabe ◽  
...  

The feeding-fasting nutritional transition triggers a dynamic change in metabolic pathways and is a model for understanding how these pathways are mutually organized. The targeted disruption of the thioredoxin binding protein-2 (TBP-2)/thioredoxin-interacting protein (Txnip)/VDUP1 gene in mice results in lethality with hypertriglyceridemia and hypoglycemia during fasting. To investigate the molecular mechanism of the nutritional transition and the role of TBP-2, microarray analyses were performed using the liver of TBP-2−/− mice in the fed and fasted states. We found that the fasting-induced reduction in the expression of lipogenic genes targeted by insulin (SREBP-1), such as FASN and THRSP, was abolished in TBP-2−/− mice, and the expression of lipoprotein lipase is down-regulated, which was consistent with the lipoprotein profile. TBP-2−/− mice also exhibited enhanced glucose-induced insulin secretion and sensitivity. Another feature of the hepatic gene expression in fed TBP-2−/− mice was the augmented expression of peroxisome proliferator activated receptor (PPAR) target genes, such as CD36, FABP2, ACOT1, and FGF21, to regulate fatty acid consumption. In TBP-2−/− mice, PPARα expression was elevated in the fed state, whereas the fasting-induced up-regulation of PPARα was attenuated. We also detected an increased expression of PPARγ coactivator-1α protein in fed TBP-2−/− mice. TBP-2 overexpression significantly inhibited PPARα-mediated transcriptional activity induced by a specific PPARα ligand in vitro. These results suggest that TBP-2 is a key regulator of PPARα expression and signaling, and coordinated regulation of PPARα and insulin secretion by TBP-2 is crucial in the feeding-fasting nutritional transition. TBP-2/Txnip is a key regulator of PPARα expression and signaling, and coordinated regulation of PPARα and insulin secretion by TBP-2/Txnip is crucial in fasting response.


2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Emma Barroso ◽  
Rosalía Rodríguez-Rodríguez ◽  
Mohammad Zarei ◽  
Javier Pizarro-Degado ◽  
Anna Planavila ◽  
...  

Abstract Background Deficiency of mitochondrial sirtuin 3 (SIRT3), a NAD+-dependent protein deacetylase that maintains redox status and lipid homeostasis, contributes to hepatic steatosis. In this study, we investigated additional mechanisms that might play a role in aggravating hepatic steatosis in Sirt3-deficient mice fed a high-fat diet (HFD). Methods Studies were conducted in wild-type (WT) and Sirt3−/− mice fed a standard diet or a HFD and in SIRT3-knockdown human Huh-7 hepatoma cells. Results Sirt3−/− mice fed a HFD presented exacerbated hepatic steatosis that was accompanied by decreased expression and DNA-binding activity of peroxisome proliferator-activated receptor (PPAR) α and of several of its target genes involved in fatty acid oxidation, compared to WT mice fed the HFD. Interestingly, Sirt3 deficiency in liver and its knockdown in Huh-7 cells resulted in upregulation of the nuclear levels of LIPIN1, a PPARα co-activator, and of the protein that controls its levels and localization, hypoxia-inducible factor 1α (HIF-1α). These changes were prevented by lipid exposure through a mechanism that might involve a decrease in succinate levels. Finally, Sirt3−/− mice fed the HFD showed increased levels of some proteins involved in lipid uptake, such as CD36 and the VLDL receptor. The upregulation in CD36 was confirmed in Huh-7 cells treated with a SIRT3 inhibitor or transfected with SIRT3 siRNA and incubated with palmitate, an effect that was prevented by the Nrf2 inhibitor ML385. Conclusion These findings demonstrate new mechanisms by which Sirt3 deficiency contributes to hepatic steatosis. Graphical abstract


Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1259 ◽  
Author(s):  
Garima Maheshwari ◽  
Robert Ringseis ◽  
Gaiping Wen ◽  
Denise K. Gessner ◽  
Johanna Rost ◽  
...  

The study aimed to test the hypothesis that monomethyl branched-chain fatty acids (BCFAs) and a lipid extract of Conidiobolus heterosporus (CHLE), rich in monomethyl BCFAs, are able to activate the nuclear transcription factor peroxisome proliferator-activated receptor alpha (PPARalpha). Rat Fao cells were incubated with the monomethyl BCFAs 12-methyltridecanoic acid (MTriA), 12-methyltetradecanoic acid (MTA), isopalmitic acid (IPA) and 14-methylhexadecanoic acid (MHD), and the direct activation of PPARalpha was evaluated by reporter gene assay using a PPARalpha responsive reporter gene. Furthermore, Fao cells were incubated with different concentrations of the CHLE and PPARalpha activation was also evaluated by using the reporter gene assay, and by determining the mRNA concentrations of selected PPARalpha target genes by real-time RT-PCR. The reporter gene assay revealed that IPA and the CHLE, but not MTriA, MHD and MTA, activate the PPARalpha responsive reporter gene. CHLE dose-dependently increased mRNA concentrations of the PPARalpha target genes acyl-CoA oxidase (ACOX1), cytochrome P450 4A1 (CYP4A1), carnitine palmitoyltransferase 1A (CPT1A) and solute carrier family 22 (organic cation/carnitine transporter), member 5 (SLC22A5). In conclusion, the monomethyl BCFA IPA is a potent PPARalpha activator. CHLE activates PPARalpha-dependent gene expression in Fao cells, an effect that is possibly mediated by IPA.


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