| 1. |
- Mandenius, Carl-Fredrik, et al.
(författare)
-
Toward Preclinical Predictive Drug Testing for Metabolism and Hepatotoxicity by Using In Vitro Models Derived from Human Embryonic Stem Cells and Human Cell Lines - A Report on the Vitrocellomics EU-project
- 2011
-
Ingår i: ATLA-ALTERNATIVES TO LABORATORY ANIMALS. - : Fund for Replacement of Animals in Medical Experiments; 1999. - 0261-1929 .- 2632-3559. ; 39:2, s. 147-171
-
Tidskriftsartikel (refereegranskat)abstract
- Drug-induced liver injury is a common reason for drug attrition in late clinical phases, and even for post-launch withdrawals. As a consequence, there is a broad consensus in the pharmaceutical industry, and within regulatory authorities, that a significant improvement of the current in vitro test methodologies for accurate assessment and prediction of such adverse effects is needed. For this purpose, appropriate in vivo-like hepatic in vitro models are necessary, in addition to novel sources of human hepatocytes. In this report, we describe recent and ongoing research toward the use of human embryonic stem cell (hESC)-derived hepatic cells, in conjunction with new and improved test methods, for evaluating drug metabolism and hepatotoxicity. Recent progress on the directed differentiation of human embryonic stem cells to the functional hepatic phenotype is reported, as well as the development and adaptation of bioreactors and toxicity assay technologies for the testing of hepatic cells. The aim of achieving a testing platform for metabolism and hepatotoxicity assessment, based on hESC-derived hepatic cells, has advanced markedly in the last 2-3 years. However, great challenges still remain, before such new test systems could be routinely used by the industry. In particular, we give an overview of results from the Vitrocellomics project (EU Framework 6) and discuss these in relation to the current state-of-the-art and the remaining difficulties, with suggestions on how to proceed before such in vitro systems can be implemented in industrial discovery and development settings and in regulatory acceptance.
|
|
| 2. |
|
|
| 3. |
- Brolen, Gabriella, et al.
(författare)
-
Hepatocyte-like cells derived from human embryonic stem cells specifically via definitive endoderm and a progenitor stage
- 2010
-
Ingår i: Journal of Biotechnology. - : Elsevier BV. - 1873-4863 .- 0168-1656. ; 145:3, s. 284-294
-
Tidskriftsartikel (refereegranskat)abstract
- Human embryonic stem cells offer a potential unlimited supply for functional hepatocytes, since they can differentiate into hepatocyte-like cells displaying a characteristic hepatic morphology and expressing various hepatic markers. These cells could be used in various applications such as studies of drug metabolism and hepatotoxicity, which however, would require a significant expression of drug metabolizing enzymes. To derive these cells we use a stepwise differentiation protocol where growth- and maturation factors are added. The first phase involves the formation of definitive endoderm. Next, these cells are treated with factors known to promote the induction and proliferation towards hepatic progenitor cell types. In the last phase the cells are terminally differentiated and maturated into functional hepatocyte-like cells. The cultures were characterized by analysis of endodermal or hepatic markers and compared to cultures derived without induction via definitive endoderm. Hepatic functions such as urea secretion, glycogen storage, indocyanine green uptake and secretion, and cytochrome P450-expression and activity were evaluated. The DE-Hep showed a hepatocyte morphology with sub-organized cells and exhibited many liver-functions including transporter activity and capacity to metabolize drugs specific for important cytochrome P450 sub-families. This represents an importantstep in differentiation of hESC into functional hepatocytes. (C) 2009 Elsevier B.V. All rights reserved.
|
|
| 4. |
- Choong, Eva, et al.
(författare)
-
Sex difference in formation of propofol metabolites : a replication study
- 2013
-
Ingår i: Basic & Clinical Pharmacology & Toxicology. - : Wiley. - 1742-7835 .- 1742-7843. ; 113:2, s. 126-131
-
Tidskriftsartikel (refereegranskat)abstract
- Women recover faster from propofol anaesthesia and have been described to have a higher incidence of awareness during surgery, compared to men - an effect that may be inherent in sex differences in propofol metabolism. In an observational study, 98 ASA I-II patients treated with continuous propofol infusion were recruited. The associations between sex and CYP2B6 and UGT1A9 polymorphisms with dose- and weight-adjusted area under the total plasma level time curves (AUC) for propofol, and its metabolites propofol glucuronide (PG), 4-hydroxypropofol (OHP) and hydroxyl glucuronide metabolites 4-hydroxypropofol-1-O-β-D-glucuronide (Q1G) and 4-hydroxypropofol-4-O-β-D-glucuronide (Q4G), were analysed. Significantly higher AUC of PG (1.3 times, p = 0.03), Q1G (2.9 times, p < 0.001), Q4G (2.4 times, p < 0.01) and OHP (4.6 times, p = 0.01) were found in women (n = 53) than in men (n = 45) after intravenous infusion of propofol using target-controlled infusion system. There was, however, no significant impact of gene polymorphisms on propofol biotransformation. The results, which are supported by a previous pilot study using a propofol bolus dose, suggest that, compared to men, more rapid propofol metabolism may occur in women - a factor that may contribute to the mentioned differences in the efficacy of propofol anaesthesia between male and female patients.
|
|
| 5. |
- Edler, David, et al.
(författare)
-
The expression of the novel CYP2W1 enzyme is an independent prognostic factor in colorectal cancer : a pilot study.
- 2009
-
Ingår i: European Journal of Cancer. - : Elsevier BV. - 0959-8049 .- 1879-0852. ; 45:4, s. 705-712
-
Tidskriftsartikel (refereegranskat)abstract
- AIM Cytochrome P450 (CYP) enzymes are important for drug metabolism. A novel cytochrome P450 enzyme, CYP2W1, has recently been identified. This enzyme is mainly found in foetal colon tissue and in tumour tissue. In this pilot study, we have investigated the expression of CYP2W1 in 162 tumours from patients with stages II and III colorectal cancer. METHODS The expression of CYP2W1 enzyme was immunohistochemically detected using a polyclonal antibody. Staining intensity was defined using a visual grading scale from 0 to 3. Grades 0-2 were classified as low, and grade 3 was classified as high expression of CYP2W1. RESULTS About 64% of the tumours expressed a low level of CYP2W1-expression, and 36% expressed a high level. CYP2W1-expression was an independent prognostic factor for overall survival (p=0.007), where a high expression was associated with a worse clinical outcome. CONCLUSIONS Immunohistochemically assessed expression of CYP2W1 is an independent prognostic factor in patients with stages II and III colorectal cancer.
|
|
| 6. |
- Ghotbi, Roza, et al.
(författare)
-
Allele-specific expression and gene methylation in the control of CYP1A2 mRNA level in human livers
- 2009
-
Ingår i: The Pharmacogenomics Journal. - : Springer Science and Business Media LLC. - 1470-269X .- 1473-1150. ; 9:3, s. 208-217
-
Tidskriftsartikel (refereegranskat)abstract
- The basis for interindividual variation in the CYP1A2 gene expression is not fully understood and the known genetic polymorphisms in the gene provide no explanation. We investigated whether the CYP1A2 gene expression is regulated by DNA methylation and displays allele-specific expression (ASE) using 65 human livers. Forty-eight percent of the livers displayed ASE not associated to the CYP1A2 mRNA levels. The extent of DNA methylation of a CpG island including 17 CpG sites, close to the translation start site, inversely correlated with hepatic CYP1A2 mRNA levels (P=0.018). The methylation of two separate core CpG sites was strongly associated with the CYP1A2 mRNA levels (P=0.005) and ASE phenotype (P=0.01), respectively. The CYP1A2 expression in hepatoma B16A2 cells was strongly induced by treatment with 5-aza-2'-deoxycytidine. In conclusion, the CYP1A2 gene expression is influenced by the extent of DNA methylation and displays ASE, mechanisms contributing to the large interindividual differences in CYP1A2 gene expression.
|
|
| 7. |
- Ivanov, Maxim, et al.
(författare)
-
Single base resolution analysis of 5-hydroxymethylcytosine in 188 human genes : implications for hepatic gene expression
- 2016
-
Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 44:14, s. 6756-6769
-
Tidskriftsartikel (refereegranskat)abstract
- To improve the epigenomic analysis of tissues rich in 5-hydroxymethylcytosine (hmC), we developed a novel protocol called TAB-Methyl-SEQ, which allows for single base resolution profiling of both hmC and 5-methylcytosine by targeted next-generation sequencing. TAB-Methyl-SEQ data were extensively validated by a set of five methodologically different protocols. Importantly, these extensive cross-comparisons revealed that protocols based on Tet1-assisted bisulfite conversion provided more precise hmC values than TrueMethyl-based methods. A total of 109 454 CpG sites were analyzed by TAB-Methyl-SEQ for mC and hmC in 188 genes from 20 different adult human livers. We describe three types of variability of hepatic hmC profiles: (i) sample-specific variability at 40.8% of CpG sites analyzed, where the local hmC values correlate to the global hmC content of livers (measured by LC-MS), (ii) gene-specific variability, where hmC levels in the coding regions positively correlate to expression of the respective gene and (iii) site-specific variability, where prominent hmC peaks span only 1 to 3 neighboring CpG sites. Our data suggest that both the gene-and site-specific components of hmC variability might contribute to the epigenetic control of hepatic genes. The protocol described here should be useful for targeted DNA analysis in a variety of applications.
|
|
| 8. |
- Kotsovolou, Olga, et al.
(författare)
-
Hepatic drug metabolizing profile of Flinders Sensitive Line rat model of depression
- 2010
-
Ingår i: Progress in Neuro-psychopharmacology and Biological Psychiatry. - : Elsevier BV. - 0278-5846 .- 1878-4216. ; 34:6, s. 1075-1084
-
Forskningsöversikt (refereegranskat)abstract
- The Flinders Sensitive Line (FSL) rat model of depression exhibits some behavioral, neurochemical, and pharmacological features that have been reported in depressed patients and has been very effective in screening antidepressants. Major factor that determines the effectiveness and toxicity of a drug is the drug metabolizing capacity of the liver. Therefore, in order to discriminate possible differentiation in the hepatic drug metabolism between FSL rats and Sprague Dawley (SD) controls, their hepatic metabolic profile was investigated in this study. The data showed decreased glutathione (GSH) content and glutathione S-transferase (GST) activity and lower expression of certain major CYP enzymes, including the CYP2B1, CYP2C11 and CYP2D1 in FSL rats compared to SD controls. In contrast, p-nitrophenol hydroxylase (PNP), 7ethoxyresorufin-O-dealkylase (EROD) and 16 alpha-testosterone hydroxylase activities were higher in FSL rats. Interestingly, the wide spread environmental pollutant benzo(alpha)pyrene (B(alpha)P) induced CYP1A1, CYP1A2, CYP2B1/2 and ALDH3c at a lesser extend in FSL than in SD rats, whereas the antidepressant mirtazapine (MIRT) up-regulated CYP1A1/2, CYP2C11, CYP2D1, CYP2E1 and CYP3A1/2, mainly, in FSL rats. The drug also further increased ALDH3c whereas suppressed GSH content in B(a)P-exposed FSL rats. In conclusion, several key enzymes of the hepatic biotransformation machinery are differentially expressed in FSL than in SD rats, a condition that may influence the outcome of drug therapy. The MIRT-induced up-regulation of several drug-metabolizing enzymes indicates the critical role of antidepressant treatment that should be always taken into account in the designing of treatment and interpretation of insufficient pharmacotherapy or drug toxicity.
|
|
| 9. |
- Larsson, Susanna C, et al.
(författare)
-
Dietary long-chain n-3 fatty acids for the prevention of cancer : a review of potential mechanisms
- 2004
-
Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 79:6, s. 935-45
-
Tidskriftsartikel (refereegranskat)abstract
- Increasing evidence from animal and in vitro studies indicates that n-3 fatty acids, especially the long-chain polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid, present in fatty fish and fish oils inhibit carcinogenesis. The epidemiologic data on the association between fish consumption, as a surrogate marker for n-3 fatty acid intake, and cancer risk are, however, somewhat less consistent. This review highlights current knowledge of the potential mechanisms of the anticarcinogenic actions of n-3 fatty acids. Moreover, a possible explanation of why some epidemiologic studies failed to find an association between n-3 fatty acid intake and cancer risk is provided. Several molecular mechanisms whereby n-3 fatty acids may modify the carcinogenic process have been proposed. These include suppression of arachidonic acid-derived eicosanoid biosynthesis; influences on transcription factor activity, gene expression, and signal transduction pathways; alteration of estrogen metabolism; increased or decreased production of free radicals and reactive oxygen species; and mechanisms involving insulin sensitivity and membrane fluidity. Further studies are needed to evaluate and verify these mechanisms in humans to gain more understanding of the effects of n-3 fatty acid intake on cancer risk.
|
|
| 10. |
- Lauschke, Volker M., et al.
(författare)
-
3D Primary Hepatocyte Culture Systems for Analyses of Liver Diseases, Drug Metabolism, and Toxicity : Emerging Culture Paradigms and Applications
- 2019
-
Ingår i: Biotechnology Journal. - : Wiley-VCH Verlagsgesellschaft. - 1860-6768 .- 1860-7314. ; 14:7
-
Forskningsöversikt (refereegranskat)abstract
- Recent research has shown that the maintenance of relevant liver functions ex vivo requires models in which the cells exhibit an in vivo-like phenotype, often achieved by reconstitution of appropriate cellular interactions. Multiple different models have been presented that differ in the cells utilized, media, and culture conditions. Furthermore, several technologically different approaches have been presented including bioreactors, chips, and plate-based systems in fluidic or static media constituting of chemically diverse materials. Using such models, the ability to predict drug metabolism, drug toxicity, and liver functionality have increased tremendously as compared to conventional in vitro models in which cells are cultured as 2D monolayers. Here, the authors highlight important considerations for microphysiological systems for primary hepatocyte culture, review current culture paradigms, and discuss their opportunities for studies of drug metabolism, hepatotoxicity, liver biology, and disease.
|
|
| 11. |
- Lee, Mi-Young, et al.
(författare)
-
Role of cytochrome P450 2C8*3 (CYP2C8*3) in paclitaxel metabolism and paclitaxel-induced neurotoxicity
- 2015
-
Ingår i: Pharmacogenomics (London). - : Future Medicine. - 1462-2416 .- 1744-8042. ; 16:9, s. 929-937
-
Tidskriftsartikel (refereegranskat)abstract
- Aim: The CYP2C8*3 allele has been suggested as a risk factor for paclitaxel-induced neuropathy but the data hitherto published are conflicting. Materials and methods: In total 435 patients were investigated with respect to maximum neuropathy grade and accumulated paclitaxel dose. The enzymatic properties of CYP2C8.3 variant were analyzed using heterologous mammalian HEK293 cell expression system. Results: No significant association between CYP2C8*3 allele and neuropathy was found, although a trend was observed. The paclitaxel and amodiaquine metabolism by CYP2C8.3 were found similar to CYP2C8.1, whereas CYP2C8.3 was more efficient in the metabolism of rosiglitazone. Conclusion: These results indicate a difference in substrate specificity between CYP2C8.1 and CYP2C8.3; however, the CYP2C8*3 allele has no major impact on paclitaxel metabolism in vitro or of paclitaxel-induced neuropathy in vivo. Original submitted on 6 February 2015; revision submitted on 9 April 2015
|
|
| 12. |
- Loryan, Irena, 1977-, et al.
(författare)
-
Influence of sex on propofol metabolism, a pilot study : implications for propofol anesthesia
- 2012
-
Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 68:4, s. 397-406
-
Tidskriftsartikel (refereegranskat)abstract
- PurposeThe basis of high intersubject variability of propofol metabolism is unclear. Therefore, we examined the influence of genetic polymorphisms of the key metabolizing enzymes cytochrome P450 2B6 (CYP2B6) and uridine diphosphate (UDP)-glucuronosyltransferase 1A9 (UGT1A9), age, and sex on propofol biotransformation in vitro and in vivo.MethodsPlasma concentrations of propofol, 4-hydroxypropofol, and their glucuronides were measured over 20 min in 105 patients after a single intravenous bolus of propofol. Propofol 4-hydroxylation activity, genotypes, and content of CYP2B6 protein in 68 human livers were determined. The common single nucleotide polymorphisms (SNPs) for the CYP2B6 and UGT1A9 genes were analyzed by polymerase chain reaction (PCR).ResultsPlasma levels of propofol metabolites showed high interindividual variability (range of coefficient of variation 89–128%). This was supported by in vitro data showing similar variability of propofol 4-hydroxylation in liver microsomes and 1.9-fold higher CYP2B6 protein content in the livers from women. No significant relationships were revealed between the SNPs studied and propofol metabolism. However, patients’ sex had a pronounced effect on propofol metabolism. Thus, women had higher amounts of propofol glucuronide (1.25-fold; p = 0.03), 4-hydroxypropofol-1-glucuronide (2.1-fold; p = 0.0009), and 4-hydroxypropofol-4-glucuronide (1.7-fold; p = 0.02) as shown by the weight-corrected area under the time–plasma concentration curve of metabolites. Additionally, the sexual dimorphism in 4-hydroxypropofol glucuronidation was prominent in the 35- to 64-year-old subgroup.ConclusionsNo significant effects of CYP2B6 and UGT1A9 SNPs or age on propofol metabolism were revealed in this pilot study, but there was a pronounced effect of sex, a finding that indicates an important factor for the previously described sex difference in systemic clearance of propofol seen.
|
|
| 13. |
- Lundqvist, Johan, 1979-
(författare)
-
Enzymatic Regulation of Steroidogenesis and Nuclear Receptor Activation : Special Focus on Vitamin D and Sex Hormones
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Enzyme-catalyzed reactions are important to regulate steroidogenesis and nuclear receptor activation. The present investigation examines the role of steroid metabolism catalyzed by CYP7B1 for regulation of hormone receptor activation and the effects of vitamin D on enzymatic regulation of steroidogenesis. The study reports data indicating that CYP7B1 can regulate estrogenic signaling by converting estrogens into inactive or less active metabolites. Similar results were obtained for CYP7B1-mediated metabolism of some androgen receptor ligands, indicating that CYP7B1 can be involved also in the regulation of androgenic signaling. CYP7B1 substrates and metabolites were found to exert androgenic effects in a cell line-specific manner. Furthermore, cell line differences were observed in the expression pattern for androgen receptor comodulators. This thesis reports that 1α,25-dihydroxyvitamin D3 alters the gene expression and enzyme activity of CYP21A2 and CYP17A1 leading to suppressed production of aldosterone, dehydroepiandrosterone and androstenedione in adrenocortical cells. These are novel findings on vitamin D action. A mechanism is reported for the vitamin D-mediated regulation of the CYP21A2 gene. Data indicate that vitamin D receptor interacting repressor (VDIR) and Williams syndrome transcription factor (WSTF) are key comodulators in this novel vitamin D receptor (VDR)-mediated mechanism. Furthermore, the results indicate that altered expression levels of VDIR and WSTF can shift the suppressing effect of vitamin D to a stimulatory effect. Also, epigenetic components were found to be involved in the effects of vitamin D on CYP21A2 transcriptional rate. In addition, a functional vitamin D response element was identified in the CYP21A2 promoter. This study also reports that 1α,25-dihydroxyvitamin D3 affects sex hormone production in a tissue-specific way. Gene expression and enzyme activity of aromatase were found to be downregulated in cells derived from breast, but not in cells derived from prostate and adrenal cortex. The production of estradiol and dihydrotestosterone was altered in a tissue-selective manner following vitamin D treatment. These findings are of importance for the discussion on vitamin D as a potential anti-breast cancer agent.
|
|
| 14. |
- Milosavljević, Filip, et al.
(författare)
-
The humanised CYP2C19 transgenic mouse exhibits cerebellar atrophy and movement impairment reminiscent of ataxia
- 2023
-
Ingår i: Neuropathology and Applied Neurobiology. - : Wiley. - 0305-1846 .- 1365-2990. ; 49:1
-
Tidskriftsartikel (refereegranskat)abstract
- Aims: CYP2C19 transgenic mouse expresses the human CYP2C19 gene in the liver and developing brain, and it exhibits altered neurodevelopment associated with impairments in emotionality and locomotion. Because the validation of new animal models is essential for the understanding of the aetiology and pathophysiology of movement disorders, the objective was to characterise motoric phenotype in CYP2C19 transgenic mice and to investigate its validity as a new animal model of ataxia. Methods: The rotarod, paw-print and beam-walking tests were utilised to characterise the motoric phenotype. The volumes of 20 brain regions in CYP2C19 transgenic and wild-type mice were quantified by 9.4T gadolinium-enhanced post-mortem structural neuroimaging. Antioxidative enzymatic activity was quantified biochemically. Dopaminergic alterations were characterised by chromatographic quantification of concentrations of dopamine and its metabolites and by subsequent immunohistochemical analyses. The beam-walking test was repeated after the treatment with dopamine receptor antagonists ecopipam and raclopride. Results: CYP2C19 transgenic mice exhibit abnormal, unilateral ataxia-like gait, clasping reflex and 5.6-fold more paw-slips in the beam-walking test; the motoric phenotype was more pronounced in youth. Transgenic mice exhibited a profound reduction of 12% in cerebellar volume and a moderate reduction of 4% in hippocampal volume; both regions exhibited an increased antioxidative enzyme activity. CYP2C19 mice were hyperdopaminergic; however, the motoric impairment was not ameliorated by dopamine receptor antagonists, and there was no alteration in the number of midbrain dopaminergic neurons in CYP2C19 mice. Conclusions: Humanised CYP2C19 transgenic mice exhibit altered gait and functional motoric impairments; this phenotype is likely caused by an aberrant cerebellar development.
|
|
| 15. |
- Neve, Etienne P A, et al.
(författare)
-
Amidoxime Reductase System Containing Cytochrome b5 Type B (CYB5B) and MOSC2 Is of Importance for Lipid Synthesis in Adipocyte Mitochondria
- 2012
-
Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 287:9, s. 6307-6317
-
Tidskriftsartikel (refereegranskat)abstract
- Reduction of hydroxylamines and amidoximes is important for drug activation and detoxification of aromatic and heterocyclic amines. Such a reductase system was previously found to be of high activity in adipose tissue and liver, and furthermore, in vitro studies using recombinant truncated and purified enzymes suggested the participation of cytochrome b(5) reductase (CYB5R), cytochrome b(5) (CYB5), and molybdenum cofactor sulfurase C-terminal containing 1 and 2 (MOSC1 and -2). Here, we show that purified rat liver outer mitochondrial membrane contains high amidoxime reductase activity and that MOSC2 is exclusively localized to these membranes. Moreover, using the same membrane fraction, we could show direct binding of a radiolabeled benzamidoxime substrate to MOSC2. Following differentiation of murine 3T3-L1 cells into mature adipocytes, the MOSC2 levels as well as the amidoxime reductase activity were increased, indicating that the enzyme is highly regulated under lipogenic conditions. siRNA-mediated down-regulation of MOSC2 and the mitochondrial form of cytochrome b(5) type B (CYB5B) significantly inhibited the reductase activity in the differentiated adipocytes, whereas down-regulation of MOSC1, cytochrome b(5) type A (CYB5A), CYB5R1, CYB5R2, or CYB5R3 had no effect. Down-regulation of MOSC2 caused impaired lipid synthesis. These results demonstrate for the first time the direct involvement of MOSC2 and CYB5B in the amidoxime reductase activity in an intact cell system. We postulate the presence of a novel reductive enzyme system of importance for lipid synthesis that is exclusively localized to the outer mitochondrial membrane and is composed of CYB5B, MOSC2, and a third unknown component (a CYB5B reductase).
|
|
| 16. |
- Neve, Etienne P. A., et al.
(författare)
-
An Integrated in Vitro Model for Simultaneous Assessment of Drug Uptake, Metabolism, and Efflux
- 2013
-
Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8384 .- 1543-8392. ; 10:8, s. 3152-3163
-
Tidskriftsartikel (refereegranskat)abstract
- The absorption, distribution, metabolism, and excretion (ADME) of drugs in vivo are to a large extent dependent on different transport and metabolism routes. Elucidation of this complex transport-metabolism interplay is a major challenge in drug development and at present no in vitro models suitable for this purpose are at hand. The aim of this study was to develop flexible, well-controlled, easy-to-use, integrated cell models, where drug transport and drug metabolism processes could be studied simultaneously. HEK293 cells stably transfected with the organic anion transporting polypeptide 1B1 (OATP1B1) were subjected to either transient transfection or adenoviral infection to introduce the genes expressing cytochrome P450 3A4 (CYP3A4), NADPH cytochrome P450 oxidoreductase (POR), cytochrome b(5) (CYB5A), and multidrug resistance protein 1 (MDR1), in different combinations. Thereafter, the time and concentration dependent transport and metabolism of two well-characterized statins, atorvastatin (acid and lactone forms) and simvastatin (acid form), were determined in the different models. The results show that CYP3A4-dependent metabolism of the more hydrophilic atorvastatin acid was dependent on OATP1B1 uptake and influenced by MDR1 efflux. In contrast, the metabolism of the more lipophilic atorvastatin lactone was not affected by active transport, whereas the metabolism of simvastatin acid was less influenced by active transport than atorvastatin acid. Our results, together with the models being applicative for any combination of drug transporters and CYP metabolizing enzymes of choice, provide proof-of-concept for the potential of the new integrated cell models presented as valuable screening tools in drug discovery and development
|
|
| 17. |
- Oscarsson, Mikael, et al.
(författare)
-
Genotyping of human cytochrome P450 2A6 (CYP2A6), a nicotine C-oxidase
- 1998
-
Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 438:3, s. 201-205
-
Tidskriftsartikel (refereegranskat)abstract
- Cytochrome P450 2A6 (CYP2A6) is a polymorphic enzyme responsible for the oxidation of certain precarcinogens and drugs and is the major nicotine C-oxidase. The role of CYP2A6 for nicotine elimination was emphasised recently by the finding that smokers carrying defective CYP2A6 alleles consumed fewer cigarettes [Pianezza et al. (1998) Nature 393, 750]. The method used for CYP2A6 genotyping has, however, been found to give erroneous results with respect to the coumarin hydroxylase phenotype, a probe reaction for the CYP2A6 enzyme. The present study describes an allele-specific PCR genotyping method that identifies the major defective CYP2A6 allele and accurately predicts the phenotype. An allele frequency of 1-3% was observed in Finnish, Spanish, and Swedish populations, much lower than described previously.
|
|
| 18. |
- Pradip, Arvind, et al.
(författare)
-
High Content Analysis of Human Pluripotent Stem Cell Derived Hepatocytes Reveals Drug Induced Steatosis and Phospholipidosis
- 2016
-
Ingår i: Stem Cells International. - : Hindawi Publishing Corporation. - 1687-9678 .- 1687-966X. ; 2016
-
Tidskriftsartikel (refereegranskat)abstract
- Hepatotoxicity is one of the most cited reasons for withdrawal of approved drugs from the market. The use of nonclinically relevant in vitro and in vivo testing systems contributes to the high attrition rates. Recent advances in differentiating human induced pluripotent stem cells (hiPSCs) into pure cultures of hepatocyte-like cells expressing functional drug metabolizing enzymes open up possibilities for novel, more relevant human cell based toxicity models. The present study aimed to investigate the use of hiPSC derived hepatocytes for conducting mechanistic toxicity testing by image based high content analysis (HCA). The hiPSC derived hepatocytes were exposed to drugs known to cause hepatotoxicity through steatosis and phospholipidosis, measuring several endpoints representing different mechanisms involved in drug induced hepatotoxicity. The hiPSC derived hepatocytes were benchmarked to the HepG2 cell line and generated robust HCA data with low imprecision between plates and batches. The different parameters measured were detected at subcytotoxic concentrations and the order of which the compounds were categorized (as severe, moderate, mild, or nontoxic) based on the degree of injury at isomolar concentration corresponded to previously published data. Taken together, the present study shows how hiPSC derived hepatocytes can be used as a platform for screening drug induced hepatotoxicity by HCA.
|
|
| 19. |
- Ramsjö, Margareta, et al.
(författare)
-
CYP2C19 activity comparison between Swedes and Koreans : effect of genotype, sex, oral contraceptive use, and smoking
- 2010
-
Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 66:9, s. 871-7
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To compare CYP2C19 enzyme activity between Swedes and Koreans controlling for the effect of CYP2C19 genotype, sex, oral contraceptive use, and smoking habits.METHODS: CYP2C19 activity was determined in 185 healthy Swedish and 150 Korean subjects as the omeprazole/5-hydroxyomeprazole ratio (metabolic ratio; MR) using high-performance liquid chromatography. Genotyping was performed by PCR using Taqman assay.RESULTS: As expected, a higher incidence of poor metabolizers (PM) was found in Koreans (14%) compared with Swedes (3.8%) and the frequency of the CYP2C19 17 allele was very low in Koreans (0.3%). Among subjects homozygous for CYP2C19 1, Koreans displayed significantly lower CYP2C19 enzyme activity than Swedes (p < 0.000001). Interestingly, in Koreans a pronounced gender difference was apparent: females (n = 24) had significantly lower MR than males (n = 30; p < 0.0001), but such a gender difference was not seen among Swedes. Swedish OC users had a higher MR than non-users (p < 0.00001), whereas OC was only used by one Korean. No effects of smoking were observed.CONCLUSIONS: We find specific gender-dependent effects of CYP2C19 activity in Koreans, but not in Swedes. Controlling for the effect of genotype and sex, Koreans display lower CYP2C19 activity than Swedes. The genetic, epigenetic or environmental basis for this difference remains to be identified.
|
|
| 20. |
- Rodriguez-Antona, Cristina, et al.
(författare)
-
Molecular genetics and epigenetics of the cytochrome P450 gene family and its relevance for cancer risk and treatment
- 2010
-
Ingår i: Human Genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 127:1, s. 1-17
-
Forskningsöversikt (refereegranskat)abstract
- The cytochromes P450 (CYPs) are very efficient catalysts of foreign compound metabolism and are responsible for the major part of metabolism of clinically important drugs. The enzymes are important in cancer since they (a) activate dietary and environmental components to ultimate carcinogens, (b) activate or inactivate drugs used for cancer treatment, and (c) are potential targets for anticancer therapy. The genes encoding the CYP enzymes active in drug metabolism are highly polymorphic, whereas those encoding metabolism of precarcinogens are relatively conserved. A vast amount of literature is present where investigators have tried to link genetic polymorphism in CYPs to cancer susceptibility, although not much conclusive data have hitherto been obtained, with exception of CYP2A6 polymorphism and tobacco induced cancer, to a great extent because of lack of important functional polymorphisms in the genes studied. With respect to anticancer treatment, the genetic CYP polymorphism is of greater importance, where treatment with tamoxifen, but also with cyclophosphamide and maybe thalidomide is influenced by CYP genetic variants. In the present review we present updates on CYP genetics, cancer risk and treatment and also epigenetic aspects of interindividual variability in CYP expression and the use of these enzymes as targets for cancer therapy. We conclude that the CYP polymorphism does not predict cancer susceptibility to any large extent but that this polymorphism might be an important factor for optimal cancer therapy using selected anticancer agents.
|
|
| 21. |
- Sivertsson, Louise, et al.
(författare)
-
Hepatic differentiation and maturation of human embryonic stem cells cultured in a perfused three-dimensional bioreactor
- 2013
-
Ingår i: Stem Cells and Development. - : Mary Ann Liebert. - 1547-3287 .- 1557-8534. ; 22:4, s. 581-594
-
Tidskriftsartikel (refereegranskat)abstract
- Drug-induced liver injury is a serious and frequently occurring adverse drug reaction in the clinics and is hard to predict during preclinical studies. Today, primary hepatocytes are the most frequently used cell model for drug discovery and prediction of toxicity. However, their use is marred by high donor variability regarding drug metabolism and toxicity, and instable expression levels of liver-specific genes such as cytochromes P450. An in vitro model system based on human embryonic stem cells (hESC), with their unique properties of pluripotency and self-renewal, has potential to provide a stable and unlimited supply of human hepatocytes. Much effort has been made to direct hESC toward the hepatic lineage, mostly using 2-dimensional (2D) cultures. Although the results are encouraging, these cells lack important functionality. Here, we investigate if hepatic differentiation of hESC can be improved by using a 3-dimensional (3D) bioreactor system. Human ESCs were differentiated toward the hepatic lineage using the same cells in either the 3D or 2D system. A global transcriptional analysis identified important differences between the 2 differentiation regimes, and we identified 10 pathways, highly related to liver functions, which were significantly upregulated in cells differentiated in the bioreactor compared to 2D control cultures. The enhanced hepatic differentiation observed in the bioreactor system was also supported by immunocytochemistry. Taken together, our results suggest that hepatic differentiation of hESC is improved when using this 3D bioreactor technology as compared to 2D culture systems.
|
|
| 22. |
- Swen, JesseJ, et al.
(författare)
-
A 12-gene pharmacogenetic panel to prevent adverse drug reactions : an open-label, multicentre, controlled, cluster-randomised crossover implementation study
- 2023
-
Ingår i: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 401:10374, s. 347-356
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The benefit of pharmacogenetic testing before starting drug therapy has been well documented for several single gene-drug combinations. However, the clinical utility of a pre-emptive genotyping strategy using a pharmacogenetic panel has not been rigorously assessed.Methods: We conducted an open-label, multicentre, controlled, cluster-randomised, crossover implementation study of a 12-gene pharmacogenetic panel in 18 hospitals, nine community health centres, and 28 community pharmacies in seven European countries (Austria, Greece, Italy, the Netherlands, Slovenia, Spain, and the UK). Patients aged 18 years or older receiving a first prescription for a drug clinically recommended in the guidelines of the Dutch Pharmacogenetics Working Group (ie, the index drug) as part of routine care were eligible for inclusion. Exclusion criteria included previous genetic testing for a gene relevant to the index drug, a planned duration of treatment of less than 7 consecutive days, and severe renal or liver insufficiency. All patients gave written informed consent before taking part in the study. Participants were genotyped for 50 germline variants in 12 genes, and those with an actionable variant (ie, a drug-gene interaction test result for which the Dutch Pharmacogenetics Working Group [DPWG] recommended a change to standard-of-care drug treatment) were treated according to DPWG recommendations. Patients in the control group received standard treatment. To prepare clinicians for pre-emptive pharmacogenetic testing, local teams were educated during a site-initiation visit and online educational material was made available. The primary outcome was the occurrence of clinically relevant adverse drug reactions within the 12-week follow-up period. Analyses were irrespective of patient adherence to the DPWG guidelines. The primary analysis was done using a gatekeeping analysis, in which outcomes in people with an actionable drug-gene interaction in the study group versus the control group were compared, and only if the difference was statistically significant was an analysis done that included all of the patients in the study. Outcomes were compared between the study and control groups, both for patients with an actionable drug-gene interaction test result (ie, a result for which the DPWG recommended a change to standard-of-care drug treatment) and for all patients who received at least one dose of index drug. The safety analysis included all participants who received at least one dose of a study drug. This study is registered with ClinicalTrials.gov, NCT03093818 and is closed to new participants.Findings: Between March 7, 2017, and June 30, 2020, 41 696 patients were assessed for eligibility and 6944 (51.4 % female, 48.6% male; 97.7% self-reported European, Mediterranean, or Middle Eastern ethnicity) were enrolled and assigned to receive genotype-guided drug treatment (n=3342) or standard care (n=3602). 99 patients (52 [1.6%] of the study group and 47 [1.3%] of the control group) withdrew consent after group assignment. 652 participants (367 [11.0%] in the study group and 285 [7.9%] in the control group) were lost to follow-up. In patients with an actionable test result for the index drug (n=1558), a clinically relevant adverse drug reaction occurred in 152 (21 center dot 0%) of 725 patients in the study group and 231 (27.7%) of 833 patients in the control group (odds ratio [OR] 0 center dot 70 [95% CI 0 center dot 54-0 center dot 91]; p=0.0075), whereas for all patients, the incidence was 628 (21.5%) of 2923 patients in the study group and 934 (28. 6%) of 3270 patients in the control group (OR 0.70 [95% CI 0.61-0.79]; p <0.0001).Interpretation: Genotype-guided treatment using a 12-gene pharmacogenetic panel significantly reduced the incidence of clinically relevant adverse drug reactions and was feasible across diverse European health-care system organisations and settings. Large-scale implementation could help to make drug therapy increasingly safe.
|
|
| 23. |
- van der Wouden, Cathelijne H., et al.
(författare)
-
Generating evidence for precision medicine : considerations made by the Ubiquitous Pharmacogenomics Consortium when designing and operationalizing the PREPARE study
- 2020
-
Ingår i: Pharmacogenetics & Genomics. - 1744-6872 .- 1744-6880. ; 30:6, s. 131-144
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives Pharmacogenetic panel-based testing represents a new model for precision medicine. A sufficiently powered prospective study assessing the (cost-)effectiveness of a panel-based pharmacogenomics approach to guide pharmacotherapy is lacking. Therefore, the Ubiquitous Pharmacogenomics Consortium initiated the PREemptive Pharmacogenomic testing for prevention of Adverse drug Reactions (PREPARE) study. Here, we provide an overview of considerations made to mitigate multiple methodological challenges that emerged during the design.Methods An evaluation of considerations made when designing the PREPARE study across six domains: study aims and design, primary endpoint definition and collection of adverse drug events, inclusion and exclusion criteria, target population, pharmacogenomics intervention strategy, and statistical analyses.Results Challenges and respective solutions included: (1) defining and operationalizing a composite primary endpoint enabling measurement of the anticipated effect, by including only severe, causal, and drug genotype-associated adverse drug reactions; (2) avoiding overrepresentation of frequently prescribed drugs within the patient sample while maintaining external validity, by capping drugs of enrolment; (3) designing the pharmacogenomics intervention strategy to be applicable across ethnicities and healthcare settings; and (4) designing a statistical analysis plan to avoid dilution of effect by initially excluding patients without a gene–drug interaction in a gatekeeping analysis.Conclusion Our design considerations will enable quantification of the collective clinical utility of a panel of pharmacogenomics-markers within one trial as a proof-of-concept for pharmacogenomics-guided pharmacotherapy across multiple actionable gene–drug interactions. These considerations may prove useful to other investigators aiming to generate evidence for precision medicine.
|
|
| 24. |
|
|
| 25. |
- Yildirimman, Reha, et al.
(författare)
-
Human Embryonic Stem Cell Derived Hepatocyte-Like Cells as a Tool for In Vitro Hazard Assessment of Chemical Carcinogenicity
- 2011
-
Ingår i: Toxicological Sciences. - : Oxford University Press. - 1096-6080 .- 1096-0929. ; 124:2, s. 278-290
-
Tidskriftsartikel (refereegranskat)abstract
- Hepatocyte-like cells derived from the differentiation of human embryonic stem cells (hES-Hep) have potential to provide a human relevant in vitro test system in which to evaluate the carcinogenic hazard of chemicals. In this study, we have investigated this potential using a panel of 15 chemicals classified as noncarcinogens, genotoxic carcinogens, and nongenotoxic carcinogens and measured whole-genome transcriptome responses with gene expression microarrays. We applied an ANOVA model that identified 592 genes highly discriminative for the panel of chemicals. Supervised classification with these genes achieved a cross-validation accuracy of > 95%. Moreover, the expression of the response genes in hES-Hep was strongly correlated with that in human primary hepatocytes cultured in vitro. In order to infer mechanistic information on the consequences of chemical exposure in hES-Hep, we developed a computational method that measures the responses of biochemical pathways to the panel of treatments and showed that these responses were discriminative for the three toxicity classes and linked to carcinogenesis through p53, mitogen-activated protein kinases, and apoptosis pathway modules. It could further be shown that the discrimination of toxicity classes was improved when analyzing the microarray data at the pathway level. In summary, our results demonstrate, for the first time, the potential of human embryonic stem cell--derived hepatic cells as an in vitro model for hazard assessment of chemical carcinogenesis, although it should be noted that more compounds are needed to test the robustness of the assay.
|
|
| 26. |
- Zackrisson, Anna-Lena, 1968-
(författare)
-
Pharmacogenetics from a Forensic Perspective : CYP2D6 and CYP2C19 genotype distributions in autopsy cases
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden about 550 individuals die every year due to drug intoxication. A challenge for the forensic toxicologist is to determine whether or not the analytical results can explain intoxication as a cause of death. The most common drugs found among intoxication cases are psychiatric drugs and analgesics. Many of these drugs are metabolised by CYP-enzymes such as CYP2D6 and CYP2C19. Genetic variations, polymorphisms, in the genes coding for these enzymes can lead to an inactive enzyme resulting in poor metabolism, which can lead to adverse drug reactions, even with fatal outcome. The CYP2D6 gene can be multiplied, which can lead to an ultra-rapid metabolism if the alleles are active. Another polymorphism, in the CYP2C19 gene, can also lead to an ultra-rapid metabolism. This increased metabolism can result in insufficient drug plasma concentration and, with that, failed treatment. Alternately, if the drug is a pro-drug and has to be activated by these enzymes, it can lead to a high amount of active metabolites. There is a large inter-individual variation of these polymorphisms and also a large variation between different populations. Additional information about an individual’s pharmacogenetics may possibly facilitate the interpretation of the postmortem result and contribute to solve the “toxicological puzzle”.The general aim of this thesis was to study if genetic variation in the drug metabolising enzymes, CYP2D6 and CYP2C19 can contribute to fatal intoxication. Reliable and rapid SNP and CNV assays suitable for forensic samples using PCR and pyrosequencing were developed for CYP2D6 and genotype frequencies in a Swedish population were shown to be in concordance with earlier published data. SNP assays were established for polymorphisms in the CYP2C19 gene.Genotype distributions in fatal intoxication cases were compared with Swedish blood donors and significant difference between the materials were established. The allele CYP2D6*4 was found to be less frequent among the intoxication cases, as compared with the blood donors. No differences in CYP2C19 genotype frequencies were found between the materials. These findings are the opposite of our hypothesis that we expected to find an increased number of individuals carrying genetic variations, leading to poor metabolism among fatal intoxication cases. However, we are convinced that information concerning an individual’s genotype can be of importance in specific intoxication cases. Further studies are required to illuminate this question. Two further autopsy materials were studied; suicide cases (intoxications excluded) and natural death cases. A significant increased number of individuals carrying more than two active CYP2D6 alleles among the suicide cases were found compared to natural death cases. Furthermore, we found some significant differences between the materials when the individuals in each material were grouped according to how many active CYP2D6 alleles they carry in combination with the CYP2C19 genotype, which was divided into six subgroups. We do not currently have any explanation for the differences between the materials.
|
|
