scholarly journals Mitotane induces CYP3A4 expression via activation of the steroid and xenobiotic receptor

2012 ◽  
Vol 216 (3) ◽  
pp. 297-305 ◽  
Author(s):  
Akira Takeshita ◽  
Junko Igarashi-Migitaka ◽  
Noriyuki Koibuchi ◽  
Yasuhiro Takeuchi
Keyword(s):  
Gene Expression ◽  
Enzyme Activity ◽  
Drug Interactions ◽  
Luciferase Reporter ◽  
Pcr Analysis ◽  
Metabolic Clearance ◽  
Mrna Levels ◽  
Steroid And Xenobiotic Receptor ◽  
Cyp3a4 Enzyme ◽  
Xenobiotic Receptor

Adrenocortical carcinoma (ACC) is a rare disease with an extremely poor prognosis. Mitotane alone or in combination with other cytotoxic drugs is a common therapeutic option for ACC. In addition to its adrenolytic function, mitotane has been known for decades to increase the metabolic clearance of glucocorticoids. It was recently shown that the tyrosine kinase inhibitor sunitinib is also rapidly metabolized in patients treated with mitotane, indicating that mitotane engages in clinically relevant drug interactions. Although the precise mechanism of these interactions is not well understood, cytochrome P450 mono-oxygenase 3A4 (CYP3A4) is a key enzyme to inactivate both glucocorticoids and sunitinib. The nuclear receptor steroid and xenobiotic receptor (SXR (NR1I2)) is one of the key transcriptional regulators ofCYP3A4gene expression in the liver and intestine. A variety of xenobiotics bind to SXR and stimulate transcription of xenobiotic-response elements (XREs) located in theCYP3A4gene promoter. In this study, we evaluated the effects of mitotane on SXR-mediated transcriptionin vitroby luciferase reporter analysis, SXR–steroid receptor coactivator 1 (SRC1) interactions, quantitative real-time PCR analysis ofCYP3A4expression, SXR knockdown, and CYP3A4 enzyme activity assays using human hepatocyte-derived cells. We found that mitotane activated SXR-mediated transcription of the XREs. Mitotane recruited SRC1 to the ligand-binding domain of SXR. Mitotane increasedCYP3A4mRNA levels, which was attenuated by SXR knockdown. Finally, we showed that mitotane increased CYP3A4 enzyme activity. We conclude that mitotane can induceCYP3A4gene expression and suggest that mitotane is used cautiously due to its drug–drug interactions.

Hepatocellular expression of glucose-6-phosphatase is unaltered during hepatic regeneration

1998 ◽  
Vol 275 (4) ◽  
pp. G717-G722 ◽  
Author(s):  
Wisam F. Zakko ◽  
Carl L. Berg ◽  
John L. Gollan ◽  
Richard M. Green
Keyword(s):  
Gene Expression ◽  
Enzyme Activity ◽  
Protein Expression ◽  
Partial Hepatectomy ◽  
Initial Phase ◽  
Physiological Function ◽  
Liver Homogenate ◽  
Hepatic Regeneration ◽  
Mrna Levels ◽  
Microsomal Enzyme

Gluconeogenesis and glycogenolysis are essential hepatic functions required for glucose homeostasis. During the initial phase of hepatic regeneration, the immediate-early genes (IEG) are rapidly expressed, and the IEG RL-1 encodes for glucose-6-phosphatase (G-6- Pase). G-6- Pase is a microsomal enzyme essential for gluconeogenesis and glycogenolysis. This study employs a partial-hepatectomy model to examine the expression and activity of G-6- Pase. After partial hepatectomy, rat hepatic G-6- Pase gene expression is transcriptionally regulated, and mRNA levels are increased ≈30-fold. However, in contrast to this rapid gene induction, microsomal enzyme activity is unchanged after partial hepatectomy. Western blotting demonstrates that microsomal G-6- Pase protein expression is also unchanged after partial hepatectomy, and similar results are also noted in whole liver homogenate. Thus, despite marked induction in gene expression of the IEG G-6- Pase after partial hepatectomy, protein expression and enzyme activity remain unchanged. These data indicate that, although this hepatocyte IEG is transcriptionally regulated, the physiologically important level of regulation is posttranscriptional. This highlights the importance of correlating gene expression of IEG with protein expression and physiological function.

scholarly journals Glucocorticoid hormones downregulate histidine decarboxylase mRNA and enzyme activity in rat lung

1998 ◽  
Vol 275 (2) ◽  
pp. L407-L413 ◽  
Author(s):  
Cynthia A. Zahnow ◽  
Pertti Panula ◽  
Atsushi Yamatodani ◽  
David E. Millhorn
Keyword(s):  
Gene Expression ◽  
Enzyme Activity ◽  
Adrenal Gland ◽  
Histidine Decarboxylase ◽  
Mrna Levels ◽  
Glucocorticoid Hormones ◽  
Rat Lung ◽  
Dexamethasone Treatment ◽  
Inflammatory Disorders ◽  
Corticosterone Treatment

Histidine decarboxylase (HDC) is the primary enzyme regulating histamine biosynthesis. Histamine contributes to the pathogenesis of chronic inflammatory disorders such as asthma. Because glucocorticoids are effective in the treatment of asthma, we examined the effects of 6 h of exogenously administered dexamethasone (0.5–3,000 μg/kg ip), corticosterone (0.2–200 mg/kg ip), or endogenously elevated corticosterone (via exposure of rats to 10% oxygen) on HDC expression in the rat lung. HDC transcripts were decreased ∼73% with dexamethasone treatment, 57% with corticosterone treatment, and 50% with exposure to 10% oxygen. Likewise, HDC enzyme activity was decreased 80% by treatment with dexamethasone and corticosterone and 60% by exposure to 10% oxygen. Adrenalectomy prevented the decreases in HDC mRNA and enzyme activity observed in rats exposed to 10% oxygen, suggesting that the adrenal gland is necessary for the mediation of hypoxic effects on HDC gene expression. These results demonstrate that corticosteroids initiate a process that leads to the decrease of HDC mRNA levels and enzyme activity in rat lung.

scholarly journals Review of: Metalloproteinase axes increase β-catenin signaling in primary mouse mammary epithelial cells lacking TIMP3

2007 ◽  
Vol 10 (8) ◽  
Author(s):  
D. S. Salomon
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Target Genes ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Pcr Analysis ◽  
Mrna Levels ◽  
Specific Effects ◽  
Primary Mouse ◽  
Ductal Elongation

Citation of original article:C. V. Hojilla, I. Kim, Z. Kassiri, J. E. Fat, H. Fang, R. Khokha. Journal of Cell Science 2007; 120(6): 1050–1060.Abstract of the original article:Multiple cancers exhibit mutations in β-catenin that lead to increased stability, altered localization or amplified activity. β-Catenin is situated at the junction between the cadherin-mediated cell adhesion and Wnt signaling pathways, and TIMP3 functions to alter β-catenin signaling. Here we demonstrate that primary mouse embryonic fibroblasts (MEFs) and mammary epithelial cells (MECs) deficient in Timp3 have increased β-catenin signaling. Functionally, the loss of TIMP3 exerted cell-type-specific effects, with Timp3−/− MEFs being more sensitive and Timp3−/− MECs more resistant to EGTA-induced cell detachment than the wild type. Timp3−/− MECs had higher dephosphorylated β-catenin levels and increased β-catenin transcriptional activity as measured by TCF/LEF-responsive reporter assays. Real-time PCR analysis of β-catenin target genes in MEFs and MECs showed no alteration in Myc, decreased Ccnd1 (cyclin D1) and increased Mmp7 mRNA levels upon loss of TIMP3, with the latter occurring only in epithelial cells. Recombinant TIMP3 and synthetic metalloproteinase inhibitors reverted the increase in dephosphorylated β-catenin, decrease in Ccnd1 gene expression and increase in Mmp7 gene expression. Physiologically, Timp3−/− mammary glands displayed accelerated mammary ductal elongation during pubertal morphogenesis. Gain-of-function studies using slow-release TIMP-containing pellets revealed distinct effects of individual TIMPs on ductal morphogenesis. Recombinant TIMP1, TIMP3 and TIMP4 inhibited ductal elongation whereas TIMP2 promoted this process.

scholarly journals Regulation of GLUT4 gene expression by SREBP-1c in adipocytes

2006 ◽  
Vol 399 (1) ◽  
pp. 131-139 ◽  
Author(s):  
Seung-Soon Im ◽  
Sool-Ki Kwon ◽  
Seung-Youn Kang ◽  
Tae-Hyun Kim ◽  
Ha-Il Kim ◽  
...  
Keyword(s):  
Gene Expression ◽  
Adipose Tissue ◽  
Glucose Transporter ◽  
Regulatory Element ◽  
Diabetic Rats ◽  
Dominant Negative ◽  
Luciferase Reporter ◽  
Mrna Levels ◽  
Response Element ◽  
Glut4 Gene Expression

Expression of the GLUT4 (glucose transporter type 4 isoform) gene in adipocytes is subject to hormonal or metabolic control. In the present study, we have characterized an adipose tissue transcription factor that is influenced by fasting/refeeding regimens and insulin. Northern blotting showed that refeeding increased GLUT4 mRNA levels for 24 h in adipose tissue. Consistent with an increased GLUT4 gene expression, the mRNA levels of SREBP (sterol-regulatory-element-binding protein)-1c in adipose tissue were also increased by refeeding. In streptozotocin-induced diabetic rats, insulin treatment increased the mRNA levels of GLUT4 in adipose tissue. Serial deletion, luciferase reporter assays and electrophoretic mobility-shift assay studies indicated that the putative sterol response element is located in the region between bases −109 and −100 of the human GLUT4 promoter. Transduction of the SREBP-1c dominant negative form to differentiated 3T3-L1 adipocytes caused a reduction in the mRNA levels of GLUT4, suggesting that SREBP-1c mediates the transcription of GLUT4. In vivo chromatin immunoprecipitation revealed that refeeding increased the binding of SREBP-1 to the putative sterol-response element in the GLUT4. Furthermore, treating streptozotocin-induced diabetic rats with insulin restored SREBP-1 binding. In addition, we have identified an Sp1 binding site adjacent to the functional sterol-response element in the GLUT4 promoter. The Sp1 site appears to play an additive role in SREBP-1c mediated GLUT4 gene upregulation. These results suggest that upregulation of GLUT4 gene transcription might be directly mediated by SREBP-1c in adipose tissue.

Trans-resveratrol modulates the catalytic activity and mRNA expression of the procarcinogen-activating human cytochrome P450 1B1

2000 ◽  
Vol 78 (11) ◽  
pp. 874-881 ◽  
Author(s):  
Thomas KH Chang ◽  
Wendy BK Lee ◽  
Hin Hin Ko
Keyword(s):  
Gene Expression ◽  
Cytochrome P450 ◽  
Catalytic Activity ◽  
Pcr Analysis ◽  
Mrna Levels ◽  
Toxic Response ◽  
Cytochrome P450 1B1 ◽  
Cyp1b1 Mrna ◽  
Mcf 7

The present study was performed to determine if trans-resveratrol (3,5,4'-trihydroxy-trans-stilbene) modulates the catalytic activity and gene expression of cytochrome P450 1B1 (CYP1B1). In vitro, trans-resveratrol decreased human recombinant CYP1B1-catalyzed 7-ethoxyresorufin O-dealkylation activity, with an IC50 value of 1.4 ± 0.2 µM (mean ± SEM). Enzyme kinetic analysis indicated that trans-resveratrol inhibited CYP1B1 enzyme activity by a mixed-type inhibition and the apparent Ki was 0.75 ± 0.06 µM. To determine if trans-resveratrol modulates constitutive CYP1B1 gene expression, cultured MCF-7 human breast carcinoma cells were treated with trans-resveratrol. As indicated by RT-PCR analysis, treatment of MCF-7 cells with 10 µM trans-resveratrol decreased relative CYP1B1 mRNA levels after 5 h, but not after 1.5 or 3 h, of exposure. trans-Resveratrol treatment at 5, 7.5, 10, or 20 µM for 5 h produced a concentration-dependent decrease in CYP1B1 mRNA levels. The extent of suppression was ~50% at 20 µM concentration. The suppressive effect was not a consequence of a toxic response to the compound as assessed by a cell proliferation assay. Overall, our novel finding that trans-resveratrol inhibits the catalytic activity and suppresses the constitutive gene expression of CYP1B1 leads to the possibility that this nutraceutical confers protection against toxicity and carcinogenicity induced by compounds that undergo CYP1B1-catalyzed bioactivation.Key words: cytochrome P450, CYP1B1, 7-ethoxyresorufin, nutraceutical, trans-resveratrol.

Secretoneurin is a potential paracrine factor from lactotrophs stimulating gonadotropin release in the goldfish pituitary

2010 ◽  
Vol 299 (5) ◽  
pp. R1290-R1297 ◽  
Author(s):  
E. Zhao ◽  
Caleb L. Grey ◽  
Dapeng Zhang ◽  
Jan A. Mennigen ◽  
Ajoy Basak ◽  
...  
Keyword(s):  
Gene Expression ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Time Course ◽  
Pcr Analysis ◽  
Pituitary Cells ◽  
Mrna Levels ◽  
Paracrine Factor ◽  
Lh Release

Secretoneurin (SN) is a functional neuropeptide derived from the evolutionarily conserved part of precursor protein secretogranin II (SgII). In the time course study, SN (10 nM) stimulates luteinizing hormone (LH) production and secretion after 6 h of static incubation of goldfish pituitary cells. Due to the existence of SN-immunoreactivity (SN-IR) in goldfish lactotrophs, endogenous SN might exert a paracrine effect on LH in the pituitary. In an in vitro immunoneutralization experiment, coincubation with anti-SN antiserum reduces the stimulatory effect of salmon gonadotropin-releasing hormone (sGnRH) on LH release by 64%. Using Western blot analysis, we demonstrate that sGnRH significantly increases the expression of the major SgII-derived peptide (∼57 kDa, with SN-IR) and prolactin (PRL) after 12 h in the static culture of goldfish pituitary cells. Furthermore, there exists a significant correlation between the levels of these two proteins ( R = 0.76, P = 0.004). Another ∼30 kDa SgII-derived peptide containing SN is only observed in sGnRH-treated pituitary cells. Consistent with the Western blot analysis results, real-time RT-PCR analysis shows that a 12-h treatment with sGnRH induced 1.6- and 1.7-fold increments in SgII and PRL mRNA levels, respectively. SgII gene expression was also associated with PRL gene expression ( R = 0.66; P = 0.02). PRL cells loaded with the calcium-sensitive dye, fura 2/AM, respond to sGnRH treatment with increases in intracellular Ca2+ concentration level, suggesting a potential mechanism of GnRH on PRL cells and thus SgII processing and SN secretion. Taken together, endogenous lactotroph-generated SN, under the control of hypothalamic GnRH, exerts a paracrine action on neighboring gonadotrophs to stimulate LH release.

scholarly journals Effect of organic and inorganic dietary selenium supplementation on gene expression in oviduct tissues and Selenoproteins gene expression in Lohman Brown-classic laying hens

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
A. I. Muhammad ◽  
A. M. Dalia ◽  
T. C. Loh ◽  
H. Akit ◽  
A. A. Samsudin
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Laying Hens ◽  
Egg Quality ◽  
Selenium Supplementation ◽  
Pcr Analysis ◽  
Shell Gland ◽  
Mrna Levels ◽  
Active Growth ◽  
Dietary Selenium

Abstract Background The oviduct of a hen provides a conducive environment for egg formation, which needs a large amount of mineral elements from the blood via trans-epithelial permeability. Eggshell is the calcified layer on the outside of an egg that provides protection and is critical for egg quality. However, little is known about the genes or proteins involved in eggshell formation, and their relationship to dietary microminerals. We hypothesized that dietary selenium supplementation in chickens will influence genes involved in eggshell biomineralization, and improve laying hen antioxidant capacity. The objective of this research was to investigate how organic and inorganic dietary selenium supplementation affected mRNA expression of shell gland genes involved in eggshell biomineralization, and selenoproteins gene expression in Lohman Brown-Classic laying hens. Results Shell gland (Uterus) and liver tissue samples were collected from hens during the active growth phase of calcification (15–20 h post-ovulation) for RT-PCR analysis. In the oviduct (shell gland and magnum) and liver of laying hens, the relative expression of functional eggshell and hepatic selenoproteins genes was investigated. Results of qPCR confirmed the higher (p < 0.05) mRNA expression of OC-17 and OC-116 in shell gland of organic Se hen compared to inorganic and basal diet treatments. Similarly, dietary Se treatments affected the mRNA expression of OCX-32 and OCX-36 in the shell gland of laying hens. In the magnum, mRNA expression of OC-17 was significantly (p < 0.05) higher in hens fed-bacterial organic, while OC-116 mRNA expression was down-regulated in dietary Se supplemented groups compared to non-Se supplemented hens. Moreover, when compared to sodium selenite, only ADS18 bacterial Se showed significantly (p < 0.05) higher mRNA levels in GPX1, GPX4, DIO1, DIO2 and SELW1, while Se-yeast showed significantly (p < 0.05) higher mRNA levels in TXNRD1 than the non-Se group. Conclusions Dietary Se supplementation especially that from a bacterial organic source, improved shell gland and hepatic selenoproteins gene expression in laying hens, indicating that it could be used as a viable alternative source of Se in laying hens. The findings could suggest that organic Se upregulation of shell gland genes and hepatic selenoproteins in laying hens is efficient.

scholarly journals Signal Transduction Mechanisms for Glucagon-Induced Somatolactin Secretion and Gene Expression in Nile Tilapia (Oreochromis niloticus) Pituitary Cells

2021 ◽  
Vol 11 ◽  
Author(s):  
Chaoyi Zhang ◽  
Anji Lian ◽  
Yue Xu ◽  
Quan Jiang
Keyword(s):  
Gene Expression ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Primary Cultures ◽  
Hormone Secretion ◽  
Hek293 Cells ◽  
Luciferase Reporter ◽  
Pituitary Hormone ◽  
Pituitary Cells ◽  
Mrna Levels

Glucagon (GCG) plays a stimulatory role in pituitary hormone regulation, although previous studies have not defined the molecular mechanism whereby GCG affects pituitary hormone secretion. To this end, we identified two distinct proglucagons, Gcga and Gcgb, as well as GCG receptors, Gcgra and Gcgrb, in Nile tilapia (Oreochromis niloticus). Using the cAMP response element (CRE)-luciferase reporter system, tilapia GCGa and GCGb could reciprocally activate the two GCG receptors expressed in human embryonic kidney 293 (HEK293) cells. Quantitative real-time PCR analysis revealed that differential expression of the Gcga and Gcgb and their cognate receptors Gcgra and Gcgrb was found in the various tissues of tilapia. In particular, the Gcgrb is abundantly expressed in the neurointermediate lobe (NIL) of the pituitary gland. In primary cultures of tilapia NIL cells, GCGb effectively stimulated SL release, with parallel rises in the mRNA levels, and co-incubation with the GCG antagonist prevented GCGb-stimulated SL release. In parallel experiments, GCGb treatment dose-dependently enhanced intracellular cyclic adenosine monophosphate (cAMP) accumulation with increasing inositol 1,4,5-trisphosphate (IP3) concentration and the resulting in transient increases of Ca2+ signals in the primary NIL cell culture. Using selective pharmacological approaches, the adenylyl cyclase (AC)/cAMP/protein kinase A (PKA) and phospholipase C (PLC)/IP3/Ca2+/calmodulin (CaM)/CaMK-II pathways were shown to be involved in GCGb-induced SL release and mRNA expression. Together, these results provide evidence for the first time that GCGb can act at the pituitary level to stimulate SL release and gene expression via GCGRb through the activation of the AC/cAMP/PKA and PLC/IP3/Ca2+/CaM/CaMK-II cascades.

Endothelin ETA receptor regulates signaling and ANF gene expression via multiple G protein-linked pathways

1997 ◽  
Vol 272 (1) ◽  
pp. H130-H137 ◽  
Author(s):  
R. Hilal-Dandan ◽  
M. T. Ramirez ◽  
S. Villegas ◽  
A. Gonzalez ◽  
Y. Endo-Mochizuki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Adenylyl Cyclase ◽  
Hormonal Regulation ◽  
Ventricular Myocytes ◽  
Neonatal Rat ◽  
Luciferase Reporter ◽  
Luciferase Expression ◽  
Mrna Levels ◽  
Binding Studies ◽  
Eta Receptor

We have characterized the interaction of endothelin (ET) with cultured neonatal rat ventricular myocytes. Binding studies indicate a single population of ETA receptors [53,000 sites/cell, apparent dissociation constant (Kd) for ET-1 approximately 0.07 nM]. Analysis of mRNA levels for ET receptors using 35 cycles of reverse transcriptase-polymerase chain reaction demonstrates the presence of only ETA-receptor message. Studies with ET-1 and a variety of congeners and antagonists indicate that ETA receptors couple to both the stimulation of phosphoinositide turnover and the inhibition of adenylyl cyclase. In myocytes transfected with an atrial natriuretic factor (ANF) promoter linked to a luciferase reporter gene, ET-1 stimulates luciferase expression through an ETA receptor. These data indicate that the ETA receptor is the exclusive receptor on neonatal ventricular myocytes and that this receptor couples to both phosphoinositide hydrolysis and adenylyl cyclase. ET-1 also induces a threefold increase in mitogen-activated protein kinase (MAPK) activity, an effect that is not sensitive to pertussis toxin (PTx). By contrast, ET-stimulated ANF-luciferase expression is partially inhibited by treatment of cells with PTx, suggesting that both PTx-sensitive (Gi) and PTx-insensitive (Gq) pathways mediate the effects of ET-1 on ANF gene expression in neonatal myocytes and that hormonal regulation of ANF expression may utilize pathways in addition to the activation of MAPK.

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