scholarly journals Constitutive Androstane Receptor-Mediated Inhibition of Metformin on Phase II Metabolic Enzyme SULT2A1

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xiaowen Hu ◽  
Mengsiyu Li ◽  
Chunxue Zhang ◽  
Shuguang Pang
Keyword(s):  
Phase Ii ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Constitutive Androstane Receptor ◽  
Pregnane X Receptor ◽  
Metabolic Enzyme ◽  
Downstream Target ◽  
Treatment Of Diabetes ◽  
Amp Activated Protein Kinase

Background. Metformin, as a first-line treatment for diabetes, interacts with many protein kinases and transcription factors which affect the expression of downstream target genes governing drug metabolism. Sulfotransferase, SULT2A1, one phase II metabolic enzyme, sulfonates both xenobiotic and endobiotic compounds to accelerate drug excretion. Herein, we designed experiments to investigate the effects and mechanisms of metformin on SULT2A1 expression in vitro. Methods. The hepatocellular carcinoma cell line, HepaRG, was cultured with different concentrations of metformin. The cell viability was measured using CCK8 kit. HepaRG was used to evaluate the protein expression of pregnane X receptor (PXR), the constitutive androstane receptor (CAR), SULT2A1, AMP-activated protein kinase (AMPK), and phosphorylation of AMPK (p-AMPK), respectively, at different concentrations of metformin with or without rifampin (human PXR activator) and CITCO (human CAR activator). The coregulators with CAR on SULT2A1 promoter response elements have also been characterized. Results. We showed that metformin did not affect the basic expression of SULT2A1 but could suppress the expression of SULT2A1 induced by the activator of human CAR. Investigations revealed that metformin which could block CAR nuclear translocation further suppress SULT2A1. In addition, we found that the prevented CAR transfer into the nucleus by metformin was partially an AMPK-dependent event. Conclusion. The present study indicated that the activation of AMPK-CAR pathway mediated the suppression of SULT2A1 by metformin. Metformin may affect the metabolism and clearance of drugs which are SULT2A1 substrates. The results that emerged from this work provide substantial insights into an appropriate medication in the treatment of diabetes patients.

scholarly journals MODL-16. ABEMACICLIB, A SELECTIVE CDK4/6 INHIBITOR, RESTRICTS GROWTH OF PEDIATRIC GLIAL-LINEAGE TUMORS IN VITRO AND IN VIVO

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii414-iii414
Author(s):  
Muh-Lii Liang ◽  
Tsung-Han Hsieh ◽  
Tai-Tong Wong
Keyword(s):  
Dna Repair ◽  
Therapeutic Strategy ◽  
Target Genes ◽  
Rna Seq ◽  
Downstream Target ◽  
Rb Phosphorylation ◽  
Glial Lineage

Abstract BACKGROUND Glial-lineage tumors constitute a heterogeneous group of neoplasms, comprising gliomas, oligodendrogliomas, and ependymomas, which account for 40%–50% of all pediatric central nervous system tumors. Advances in modern neuro-oncological therapeutics are aimed at improving neoadjuvant chemotherapy and deferring radiotherapy because radiation exposure may cause long-term side effects on the developing brain in young children. Despite aggressive treatment, more than half the high-grade gliomas (pHGGs) and one-third of ependymomas exhibit recurrence within 2 years of initial treatment. METHODS By using integrated bioinformatics and through experimental validation, we found that at least one gene among CCND1, CDK4, and CDK6 was overexpressed in pHGGs and ependymomas. RESULTS The use of abemaciclib, a highly selective CDK4/6 inhibitor, effectively inhibited cell proliferation and reduced the expression of cell cycle–related and DNA repair–related gene expression, which was determined through RNA-seq analysis. The efficiency of abemaciclib was validated in vitro in pHGGs and ependymoma cells and in vivo by using subcutaneously implanted ependymoma cells from patient-derived xenograft (PDX) in mouse models. Abemaciclib demonstrated the suppression of RB phosphorylation, downstream target genes of E2F, G2M checkpoint, and DNA repair, resulting in tumor suppression. CONCLUSION Abemaciclib showed encouraging results in preclinical pediatric glial-lineage tumors models and represented a potential therapeutic strategy for treating challenging tumors in children.

MiR-30a-5p Downregulation Induces Neuronal Autophagy by Activating AMPK After 2856MHz Microwave Radiation

2021 ◽  
Author(s):  
Yanhui Hao ◽  
Wenchao Li ◽  
Hui Wang ◽  
Jing Zhang ◽  
Haoyu Wang ◽  
...  
Keyword(s):  
Microwave Radiation ◽  
Hippocampal Neurons ◽  
Target Genes ◽  
Neuronal Damage ◽  
Luciferase Reporter ◽  
Potential Health ◽  
Downstream Target ◽  
Neuronal Autophagy

Abstract Background With the development of science and technology, microwaves are being widely used. More and more attention has been paid to the potential health hazards of microwave exposure. The regulation of miR-30a-5p (miR-30a) on autophagy is involved in the pathophysiological process of many diseases. Our previous study found that 30 mW/cm2 microwave radiation could reduce miR-30a expression and activate neuronal autophagy in rat hippocampus. However, the roles played by miR-30a in microwave-induced neuronal autophagy and related mechanisms remain largely unexplored. Results In the present study, we established neuronal damage models by exposing rat hippocampal neurons and rat adrenal pheochromocytoma (PC12) cell-derived neuron-like cells to 30 mW/cm2 microwave, which resulted in miR-30a downregulation and autophagy activation in vivo and in vitro. Bioinformatics analysis was conducted, and Beclin1, Prkaa2, Irs1, Pik3r2, Rras2, Ddit4, Gabarapl2 and autophagy-related gene 12 (Atg12) were identified as potential downstream target genes of miR-30a involved in regulating autophagy. Based on our previous findings that microwave radiation can cause a neuronal energy metabolism disorder, Prkaa2, encoding adenosine 5’-monophosphate-activated protein kinase α2 (AMPKα2, an important catalytic subunit of energy sensor AMPK), was selected for further analysis. Dual-luciferase reporter assay results showed that Prkaa2 is a downstream target gene of miR-30a. Microwave radiation increased the expression and phosphorylation (Thr172) of AMPKα both in vivo and in vitro. Moreover, the transduction of cells with miR-30a mimics suppressed AMPKα2 expression, inhibited AMPKα (Thr172) phosphorylation and reduced autophagy flux in neuron-like cells. Importantly, miR-30a mimics abolished microwave-activated autophagy and inhibited microwave-induced AMPKα (Thr172) phosphorylation. Conclusions AMPKα2 was a newly founded downstream gene of miR-30a involved in autophagy regulation, and miR-30a downregulation after microwave radiation could promote neuronal autophagy by increasing AMPKα2 expression and activating AMPK signaling.

Genetic evidence for the transcriptional-activating function of Homothorax during adult fly development

Development ◽  
2001 ◽  
Vol 128 (18) ◽  
pp. 3405-3413 ◽  
Author(s):  
Adi Inbal ◽  
Naomi Halachmi ◽  
Charna Dibner ◽  
Dale Frank ◽  
Adi Salzberg
Keyword(s):  
Transcriptional Activity ◽  
Target Genes ◽  
Genetic Evidence ◽  
In Vivo Studies ◽  
Loss Of Function ◽  
Native Form ◽  
Downstream Target ◽  
Activating Function

Homothorax (HTH) is a homeobox-containing protein, which plays multiple roles in the development of the embryo and the adult fly. HTH binds to the homeotic cofactor Extradenticle (EXD) and translocates it to the nucleus. Its function within the nucleus is less clear. It was shown, mainly by in vitro studies, that HTH can bind DNA as a part of ternary HTH/EXD/HOX complexes, but little is known about the transcription regulating function of HTH-containing complexes in the context of the developing fly. Here we present genetic evidence, from in vivo studies, for the transcriptional-activating function of HTH. The HTH protein was forced to act as a transcriptional repressor by fusing it to the Engrailed (EN) repression domain, or as a transcriptional activator, by fusing it to the VP16 activation domain, without perturbing its ability to translocate EXD to the nucleus. Expression of the repressing form of HTH in otherwise wild-type imaginal discs phenocopied hth loss of function. Thus, the repressing form was working as an antimorph, suggesting that normally HTH is required to activate the transcription of downstream target genes. This conclusion was further supported by the observation that the activating form of HTH caused typical hth gain-of-function phenotypes and could rescue hth loss-of-function phenotypes. Similar results were obtained with XMeis3, the Xenopus homologue of HTH, extending the known functional similarity between the two proteins. Competition experiments demonstrated that the repressing forms of HTH or XMeis3 worked as true antimorphs competing with the transcriptional activity of the native form of HTH. We also describe the phenotypic consequences of HTH antimorph activity in derivatives of the wing, labial and genital discs. Some of the described phenotypes, for example, a proboscis-to-leg transformation, were not previously associated with alterations in HTH activity. Observing the ability of HTH antimorphs to interfere with different developmental pathways may direct us to new targets of HTH. The HTH antimorph described in this work presents a new means by which the transcriptional activity of the endogenous HTH protein can be blocked in an inducible fashion in any desired cells or tissues without interfering with nuclear localization of EXD.

scholarly journals MACC1 Suppresses Cell Apoptosis in Hepatocellular Carcinoma by Targeting the HGF/c-MET/AKT Pathway

2015 ◽  
Vol 35 (3) ◽  
pp. 983-996 ◽  
Author(s):  
Yingmin Yao ◽  
Chanwei Dou ◽  
Zhongtang Lu ◽  
Xin Zheng ◽  
Qingguang Liu
Keyword(s):  
Cell Apoptosis ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Annexin V ◽  
Akt Pathway ◽  
Caspase 9 ◽  
Dapi Staining ◽  
In Vivo Experiments

Background & Aims: To investigate the expression and prognostic value of MACC1 in patients with HCC and identify the mechanism by which MACC1 inhibits HCC cell apoptosis. Methods: MACC1 and p-AKT expression was studied using immunohistochemistry of both HCC tissues and adjacent liver tissues. qRT-PCR and western immunoblotting were used to examine the expression of target genes at the mRNA and protein levels, respectively. The MTT assay was used to assess cell viability, and cell apoptosis was determined by DAPI staining, Annexin V/PI staining and Caspase 3/7 assay. Nude mice were used to perform in vivo experiments. Results: The overexpression of MACC1 was found in HCC tissues and was correlated with poor postsurgical prognosis. There was a positive relationship between MACC1 and p-AKT expression in HCC tissues. In vitro experiments showed that MACC1 repressed HCC cell apoptosis and promoted cell growth. Knockdown of c-MET abolished the anti-apoptotic function of MACC1. Next, MACC1 was verified to activate PI3K/AKT signaling by sensitizing HGF/c-MET signaling in HCC. MACC1 overexpression enhanced the HGF-driven phosphorylation of BAD, Caspase 9 and FKHRL1 and inhibited their pro-apoptotic functions in HCC cells. Finally, MACC1 was shown to inhibit cell apoptosis and promote HCC growth in vivo. Conclusions: This investigation revealed that MACC1 overexpression predicted worse prognosis after liver resection, which was attributed to the repression of HCC cell apoptosis via a molecular mechanism in which MACC1 accelerated the activation of the HGF/c-MET/PI3K/AKT pathway and phosphorylated BAD, Caspase 9 and FKHRL1, ultimately preventing their nuclear translocation and their pro-apoptotic function.

scholarly journals Distinct Posttranscriptional Mechanisms Regulate the Activity of the Zn Finger Transcription Factor Lame duck during Drosophila Myogenesis

2006 ◽  
Vol 26 (4) ◽  
pp. 1414-1423 ◽  
Author(s):  
Hong Duan ◽  
Hanh T. Nguyen
Keyword(s):  
Skeletal Muscle ◽  
Transcription Factor ◽  
Posttranslational Modifications ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Protein Activity ◽  
Downstream Target ◽  
Muscle Formation ◽  
Lame Duck ◽  
Fusion Competent Myoblasts

ABSTRACT Skeletal muscle formation in Drosophila melanogaster requires two types of myoblasts, muscle founders and fusion-competent myoblasts. Lame duck (Lmd), a member of the Gli superfamily of transcription factors, is essential for the specification and differentiation of fusion-competent myoblasts. We report herein that appropriate levels of active Lmd protein are attained by a combination of posttranscriptional mechanisms. We provide evidence that two different regions of the Lmd protein are critical for modulating the balance between its nuclear translocation and its retention within the cytoplasm. Activation of the Lmd protein is also tempered by posttranslational modifications of the protein that do not detectably change its subcellular localization. We further show that overexpression of Lmd protein derivatives that are constitutively nuclear or hyperactive results in severe muscle defects. These findings underscore the importance of regulated Lmd protein activity in maintaining proper activation of downstream target genes, such as Mef2, within fusion-competent myoblasts.

scholarly journals Metapristone (RU486-derivative) inhibits endometrial cancer cell progress through regulating miR-492/Klf5/Nrf1 axis

2020 ◽  
Author(s):  
Yue Chang ◽  
Min Hao ◽  
Ru Jia ◽  
Yihui Zhao ◽  
Yixuan Cai ◽  
...  
Keyword(s):  
Endometrial Cancer ◽  
Cell Growth ◽  
Cancer Cell ◽  
Cell Apoptosis ◽  
Target Genes ◽  
Cancer Cell Growth ◽  
Endometrial Cancer Cell ◽  
Downstream Target

Abstract Background: Endometrial cancer is an invasive gynecological cancer prevalent in the world. The pathogenesis of endometrial cancer is related to multiple levels of regulation, referring to oestrogen, tumor-suppressor gene (e.g. PTEN ) or microRNAs (e.g. miR-23a and miR-29b). Metapristone is a hormone-related drug, which is widely used in clinical treatment of endometrial cancer. However, the underlying regulatory mechanism of metapristone on endometrial cancer is still unclear, especially the regulatory effect on microRNAs. The aim of this study is to investigate the specific molecular mechanism of metapristone regulating microRNAs in the treatment of endometrial cancer. Methods: RL95-2 cells and Ishikawa cells were used as the endometrial cancer models. MiR-492 or si-miR-492 was transfected into RL95-2 cells and Ishikawa cells to explore the role of miR-492 in endometrial cancer. The cell cancer model and mice cancer model were used to confirm the function and mechanism of metapristone affected on endometrial cancer in vitro and in vivo . Mechanically, cell proliferation was monitored using the MTT assay, cell colony formation assay and EdU assay. Luciferase reporter assay was used to identify the downstream target gene of miR492. The protein expression and RNA expression were respectively measured by western blot and qRT-PCR for cell signaling pathway research, subsequently, were verified in the mice tumor model via immunohistochemistry. Results: Metapristone as a kind of hormone-related drug significantly inhibited the endometrial cancer cell growth through regulating cell apoptosis-related gene expression. Mechanically, miR-492 and its target genes Klf5 and Nrf1 were highly expressed in the endometrial cancer cell lines, which promoted cell proliferation and inhibited cell apoptosis. Metapristone decreased the expression of miR-492 and its target genes Klf5 and Nrf1 , leading to endometrial cancer cell growth inhibition in vitro and in vivo . Conclusion: Metapristone inhibited the endometrial cancer cell growth through regulating the cell apoptosis-related signaling pathway and decreasing the expression of miR-492 and its downstream target genes ( Klf5 and Nrf1 ), which provided the theoretical basis in clinical treatment of endometrial cancer.

scholarly journals The Decrease in Farnesoid X Receptor, Pregnane X Receptor and Constitutive Androstane Receptor in the Liver after Intestinal Ischemia-Reperfusion

2012 ◽  
Vol 15 (5) ◽  
pp. 616 ◽  
Author(s):  
Jiro Ogura ◽  
Yusuke Terada ◽  
Takashi Tsujimoto ◽  
Takahiro Koizumi ◽  
Kaori Kuwayama ◽  
...  
Keyword(s):  
Western Blotting ◽  
Hepg2 Cells ◽  
Intestinal Ischemia ◽  
Ischemia Reperfusion ◽  
Constitutive Androstane Receptor ◽  
Pregnane X Receptor ◽  
Farnesoid X Receptor ◽  
Expression Levels ◽  
Intestinal Ischemia Reperfusion

Purpose. Intestinal ischemia-reperfusion (I/R) damages remote organs, including the liver, and promotes multi-organ failure (MOF). However, the molecular mechanisms underlying acute liver injury after intestinal I/R have not been completely elucidated. Farnesoid X receptor (FXR), pregnane X receptor (PXR) and constitutive androstane receptor (CAR) regulate metabolizing enzymes and transporters, and coordinately prevent hepatotoxicity reflecting an inability of appropriate excretion of endogenous toxic compounds. In this study, we assessed FXR, PXR and CAR expression levels and their localization levels in nuclei in the liver after intestinal I/R. We also investigated the effect of IL-6 on FXR, PXR and CAR expression levels and their localization levels in nuclei in in vitro experiments. Methods. We used intestinal I/R model rats. Moreover, HepG2 cells were used in in vitro study. Real-time PCR and Western blotting were used to assess mRNA and protein expression levels. Nuclear receptor localization in nuclei was analyzed by Western blotting using nuclear extracts. Results. FXR and PXR expression levels began to be decreased at 3 h, and FXR, PXR and CAR expression levels were decreased at 6 h after intestinal I/R. The localization levels of FXR, PXR and CAR in nuclei began to be decreased at 3 h, and all of them were decreased at 6 h after intestinal I/R. In HepG2 cells, FXR, PXR and CAR expression levels were decreased by 0.5-1 ng/mL, 0.5-100 ng/mL and 100 ng/mL IL-6 treatment for 24 h, respectively. FXR, PXR and CAR localization levels in nuclei were suppressed by 0.5-10 ng/mL, 10-100 ng/mL and 10-100 ng/mL IL-6 treatment for 24 h, respectively. Conclusions. FXR, PXR and CAR expression levels are decreased in the liver after intestinal I/R. IL-6 is one of main causes the decreases in expressions of these receptors. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

Knockdown of ATP8B1 expression leads to specific downregulation of the bile acid sensor FXR in HepG2 cells: effect of the FXR agonist GW4064

2009 ◽  
Vol 296 (5) ◽  
pp. G1119-G1129 ◽  
Author(s):  
Pilar Martínez-Fernández ◽  
Loreto Hierro ◽  
Paloma Jara ◽  
Luis Alvarez
Keyword(s):  
Bile Acid ◽  
Hepg2 Cells ◽  
Target Genes ◽  
Constitutive Androstane Receptor ◽  
Pregnane X Receptor ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Bile Secretion ◽  
Farnesoid X Receptor ◽  
Mrna Levels

Farnesoid X receptor (FXR) is a bile acid-sensing nuclear receptor that controls bile acid homeostasis. It has been suggested that downregulation of FXR contributes to the pathogenesis of an inherited disorder of bile secretion caused by mutations in ATP8B1. We have investigated the relationship between ATP8B1 knockdown and FXR downregulation in the human hepatoblastoma cell line HepG2. Transfection of HepG2 cells with ATP8B1 small interfering RNA (siRNA) duplexes led to a 60% reduction in the endogenous levels of ATP8B1 mRNA and protein and a concomitant decrease in FXR mRNA and protein content, as well as in FXR phosphorylation. This decrease was accompanied by a marked reduction in mRNA levels of a subset of FXR targets, such as bile salt export pump ( ABCB11), small heterodimer partner, and uridine 5′-diphosphate-glucuronosyltransferase. ATP8B1 inhibition specifically targeted FXR since mRNA expression of other prominent nuclear receptors, such as pregnane X receptor and constitutive androstane receptor, or liver-enriched transcription factors, such as hepatocyte nuclear factor 1α ( HNF-1α) and HNF-4α, was not altered. The expression of other key genes involved in bile acid synthesis, detoxification, and transport also remained unchanged upon ATP8B1 knockdown. Supporting the specificity of the effect, siRNA-mediated silencing of ABCB11, whose defect is associated with another inherited disorder of bile secretion, did not affect FXR expression. Treatment with the synthetic FXR agonist GW4064 was able to partially neutralize ATP8B1 siRNA-mediated FXR downregulation and fully counteract inhibition of FXR target genes. Collectively these findings indicate that ATP8B1 knockdown specifically downregulates FXR, and this action can be circumvented by treatment with FXR agonists.

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