Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.14.13.97 (CYP3A4)
 6,365 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Small intestinal microsomes of cynomolgus monkeys were found to catalyze hydroxylation and dealkylation of an H(1)-antihistamine prodrug, ebastine. To identify the main enzyme responsible for ebastine hydroxylation, which has been hitherto unknown, we purified two cytochrome P450 isoforms, named P450 MI-2 and P450 MI-3, from the intestinal microsomes on the basis of the hydroxylation activity. P450 MI-2 and P450 MI-3 showed the respective apparent molecular weights of 56,000 and 53,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The internal amino acid sequence of P450 MI-2 had high similarity with those of human CYP4F2, CYP4F3, and CYP4F8. The first 27 amino acid residues of P450 MI-3 were highly homologous with those of monkey CYP3A8 and human CYP3A4/5/7. Furthermore, P450 MI-2 and P450 MI-3 were recognized by anti-CYP4F and anti-CYP3A antibodies, respectively, in immunoblot analysis and catalyzed leukotriene B(4) omega-hydroxylation and testosterone 6beta-hydroxylation, which are known to be mediated by CYP4F and CYP3A, respectively. Although both enzymes had ebastine hydroxylation activity, the V(max) value of P450 MI-2 was much higher than that of P450 MI-3 (37.0 versus 0.406 nmol/min/nmol of P450), and the former K(M) (5.1 microM) was smaller than the latter K(M) (10 microM). Anti-CYP4F antibody inhibited the hydroxylation in small intestinal microsomes strongly (70%), but anti-CYP3A antibody did not. These results indicate that P450 MI-2 belongs to the CYP4F subfamily and is mainly responsible for hydroxylation of ebastine in monkey small intestinal microsomes. This suggests that the small intestinal CYP4F enzyme, P450 MI-2, can play an important role in the metabolism of drugs given orally.
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PMID:A novel cytochrome P450 enzyme responsible for the metabolism of ebastine in monkey small intestine. 1135 47

In mammals, Cytochrome P450 (CYP) enzymes are bound to membranes of the endoplasmic reticulum and mitochondria, where they are responsible for the oxidative metabolism of many xenobiotics as well as organic endogenous compounds. In humans, 57 isoforms were identified which are classified based on sequence homology. In the present work, we demonstrate the performance of a mass spectrometry-based strategy to simultaneously detect and differentiate distinct human Cytochrome P450 (CYP) isoforms including the highly similar CYP3A4, CYP3A5, CYP3A7, as well as CYP2C8, CYP2C9, CYP2C18, CYP2C19, and CYP4F2, CYP4F3, CYP4F11, CYP4F12. Compared to commonly used immunodetection methods, mass spectrometry overcomes limitations such as low antibody specificity and offers high multiplexing possibilities. Furthermore, CYP phosphorylation, which may affect various biochemical and enzymatic properties of these enzymes, is still poorly analyzed, especially in human tissues. Using titanium dioxide resin combined with tandem mass spectrometry for phosphopeptide enrichment and sequencing, we discovered eight human P450 phosphorylation sites, seven of which were novel. The data from surgical human liver samples establish that the isoforms CYP1A2, CYP2A6, CYP2B6, CYP2E1, CYP2C8, CYP2D6, CYP3A4, CYP3A7, and CYP8B1 are phosphorylated in vivo. These results will aid in further investigation of the functional significance of protein phosphorylation for this important group of enzymes.
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PMID:Distinction between human cytochrome P450 (CYP) isoforms and identification of new phosphorylation sites by mass spectrometry. 1882 26

Phenobarbital (PB) induces or represses a wide spectrum of genes in rodent liver. Much less is known about its effects in human liver. We used pangenomic cDNA microarrays to analyze concentration- and time-dependent gene expression profile changes induced by PB in the well-differentiated human HepaRG cell line. Changes in gene expression profiles clustered at specific concentration ranges and treatment times. The number of correctly annotated genes significantly modulated by at least three different PB concentration ranges (spanning 0.5 to 3.2 mM) at 20 h exposure amounted to 77 and 128 genes (p< or =0.01) at 2- and 1.8-fold filter changes, respectively. At low concentrations (0.5 and 1 mM), PB-responsive genes included the well-recognized CAR- and PXR-dependent responsive cytochromes P450 (CYP2B6, CYP3A4), sulfotransferase 2A1 and plasma transporters (ABCB1, ABCC2), as well as a number of genes critically involved in various metabolic pathways, including lipid (CYP4A11, CYP4F3), vitamin D (CYP24A1) and bile (CYP7A1 and CYP8B1) metabolism. At concentrations of 3.2 mM or higher after 20 h, and especially 48 h, increased cytotoxic effects were associated with disregulation of numerous genes related to oxidative stress, DNA repair and apoptosis. Primary human hepatocyte cultures were also exposed to 1 and 3.2 mM PB for 20 h and the changes were comparable to those found in HepaRG cells treated under the same conditions. Taken altogether, our data provide further evidence that HepaRG cells closely resemble primary human hepatocytes and provide new information on the effects of PB in human liver. These data also emphasize the importance of investigating dose- and time-dependent effects of chemicals when using toxicogenomic approaches.
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PMID:Dose- and time-dependent effects of phenobarbital on gene expression profiling in human hepatoma HepaRG cells. 1908 49

The purpose of this study was to compare the expression profiles of drug-metabolizing enzymes in the intestine of mouse, rat and human. Total RNA was isolated from the duodenum and the mRNA expression was measured using Affymetrix GeneChip oligonucleotide arrays. Detected genes from the intestine of mouse, rat and human were ca. 60% of 22690 sequences, 40% of 8739 and 47% of 12559, respectively. Total genes of metabolizing enzymes subjected in this study were 95, 33 and 68 genes in mouse, rat and human, respectively. Of phase I enzymes, the mouse exhibited abundant gene expressions for Cyp3a25, Cyp4v3, Cyp2d26, followed by Cyp2b20, Cyp2c65 and Cyp4f14, whereas, the rat showed higher expression profiles of Cyp3a9, Cyp2b19, Cyp4f1, Cyp17a1, Cyp2d18, Cyp27a1 and Cyp4f6. However, the highly expressed P450 enzymes were CYP3A4, CYP3A5, CYP4F3, CYP2C18, CYP2C9, CYP2D6, CYP3A7, CYP11B1 and CYP2B6 in the human. For phase II enzymes, glucuronosyltransferase Ugt1a6, glutathione S-transferases Gstp1, Gstm3 and Gsta2, sulfotransferase Sult1b1 and acyltransferase Dgat1 were highly expressed in the mouse. The rat revealed predominant expression of glucuronosyltransferases Ugt1a1 and Ugt1a7, sulfotransferase Sult1b1, acetyltransferase Dlat and acyltransferase Dgat1. On the other hand, in human, glucuronosyltransferases UGT2B15 and UGT2B17, glutathione S-transferases MGST3, GSTP1, GSTA2 and GSTM4, sulfotransferases ST1A3 and SULT1A2, acetyltransferases SAT1 and CRAT, and acyltransferase AGPAT2 were dominantly detected. Therefore, current data indicated substantial interspecies differences in the pattern of intestinal gene expression both for P450 enzymes and phase II drug-metabolizing enzymes. This genomic database is expected to improve our understanding of interspecies variations in estimating intestinal prehepatic clearance of oral drugs.
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PMID:Comparative gene expression of intestinal metabolizing enzymes. 1974 53

Cytochrome P450 (P450) enzymes are abundantly expressed in the human liver where they hydroxylate organic substrates. In a microarray screen performed in human liver cells, we found a group of eleven P450 genes whose expression was induced by p53 (CYP3A4, CYP3A43, CYP3A5, CYP3A7, CYP4F2, CYP4F3, CYP4F11, CYP4F12, CYP19A1, CYP21A2 and CYP24A1). The mode of regulation of four representative genes (CYP3A4, CYP3A7, CYP4F2 and CYP4F3) was further characterized. The genes were induced in a p53-dependent manner in HepG2 and Huh6 cells (both are cancer-derived human liver cells) and in primary liver cells isolated from human donors. Furthermore, p53 was found to bind to p53-responsive elements in the genes' DNA-regulatory regions and to enhance their transcription in a reporter gene assay. Importantly, when p53 was activated following the administration of either of three different anticancer chemotherapeutic agents (cisplatin, etoposide or doxorubicin), it was able to induce CYP3A genes, which are the main factors in systemic clearance of these agents. Finally, the p53-dependent induction of P450 genes following either Nutlin or chemotherapy treatment led to enhanced P450 enzymatic activity. Thus, in addition to the well-established role of p53 at the tumor site, our data unravels a novel function of hepatic p53 in inducing P450 enzymes and position p53 as a major factor in the hepatic response to xenobiotic and metabolic signals. Importantly, this study reveals a novel pathway for the induction of CYP3As by their substrates through p53, warranting the need for careful consideration when designing systemically administered chemotherapeutic regimens.
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PMID:Chemotherapeutic agents induce the expression and activity of their clearing enzyme CYP3A4 by activating p53. 2305 12

Dapagliflozin, empagliflozin, tofogliflozin, selective inhibitors of sodium-glucose cotransporter 2 (SGLT2), is used clinically to reduce circulation glucose levels in patients with type 2 diabetes mellitus by blocking the reabsorption of glucose by the kidneys. Dapagliflozin is metabolized and inactivated by UGT1A9. Empagliflozin is metabolized and inactivated by UGT1A9 and by other related isoforms UGT2B7, UGT1A3, and UGT1A8. Tofogliflozin is metabolized and inactivated by five different enzymes CYP2C18, CYP3A4, CYP3A5, CYP4A11, and CYP4F3. Dapagliflozin treatment of HCT116 cells, which express SGLT2 but not UGT1A9, results in the loss of cell adhesion, whereas HepG2 cells, which express both SGLT2 and UGT1A9, are resistant to the adhesion-related effects of dapagliflozin. PANC-1 and H1792 cells, which do not express either SGLT2 or UGT1A9, are also resistant to adhesion related effects of dapagliflozin. On the other hand, either empagliflozin or tofogliflozin treatment of HCT116, HepG2, PANC-1, and H1792 cells are resistant to the adhesion-related effects as observed in dapagliflozin treated HCT116 cells. Knockdown of UGT1A9 by shRNA in HepG2 cells increased dapagliflozin sensitivity, whereas the overexpression of UGT1A9 in HCT116 cells protected against dapagliflozin-dependent loos of cell adhesion. Dapagliflozin treatment had no effect on cellular interactions with fibronectin, vitronectin, or laminin, but it induced a loss of interaction with collagen I and IV. In parallel, dapagliflozin treatment reduced protein levels of the full-length discoidin domain receptor I (DDR1), concomitant with appearance of DDR1 cleavage products and ectodomain shedding of DDR1. In line with these observations, unmetabolized dapagliflozin increased ADAM10 activity. Dapagliflozin treatment also significantly reduced Y792 tyrosine phosphorylation of DDR1 leading to decrement of DDR1 function and detachment of cancer cells. Concomitant with these lines of results, we experienced that CEA in patients with colon cancer, which express SGLT2 but not UGT1A9, and type 2 diabetes mellitus treated by dapagliflozin in addition to chemotherapy was decreased (case 1). CEA in patients with colon cancer, which express SGLT2 but not UGT1A9, and type 2 diabetes mellitus was treated by dapagliflozin alone after radiation therapy was decreased but started to rise after cessation of dapagliflozin (case 2). CA19-9 in two of patients with pancreatic cancer and type 2 diabetes mellitus was resistant to the combination therapy of dapagliflozin and chemotherapy (case 3 and 4 respectively). PIVKAII in patients with liver cancer and type 2 diabetes mellitus, and CYFRA in patients with squamous lung cancer and type 2 diabetes mellitus was also resistant the combination therapy of dapagliflozin and chemotherapy (case 5 and 6 respectively). Taken together, these data suggest a potential role for dapagliflozin anticancer therapy against colon cancer cells that express SGLT2, but not UGT1A9.
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PMID:Dapagliflozin Inhibits Cell Adhesion to Collagen I and IV and Increases Ectodomain Proteolytic Cleavage of DDR1 by Increasing ADAM10 Activity. 3197 55