Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.44 (AGT)
 770 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epidemiological evidence has been supporting a relationship between dietary aflatoxin B1 (AFB1) exposure, development of human primary hepatocellular carcinoma (HCC) and mutations in the p53 tumor suppressor gene. However, the correlation between the observed p53 mutations, the AFB1 DNA adducts and their activation pathways has not been elucidated. Development of relevant cellular in vitro models, taking into account species and tissue specificity, could significantly contribute to the knowledge of cytotoxicity and genotoxicity mechanisms of chemical procarcinogens, such as AFB1, in humans. For this purpose a non-tumorigenic SV40-immortalized human liver epithelial cell line (THLE cells) which retained most of the phase II enzymes, but had markedly reduced phase I activities was used for stable expression of the human CYP1A2, CYP2A6, CYP2B6 and CYP3A4 cDNA. The four genetically engineered cell lines (T5-1A2, T5-2A6, T5-2B6 and T5-3A4) produced high levels of the specific CYP450 proteins and showed comparable or higher catalytic activities related to the CYP450 expression when compared to human hepatocytes. The T5-1A2, T5-2A6, T5-2B6 and T5-3A4 cell lines exhibited a very high sensitivity to the cytotoxic effects of AFB1 and were approximately 125-, 2-, 2- and 15-fold, respectively, more sensitive than the control T5-neo cells, transfected with an expressing vector which does not contain CYP450 cDNA. In the CYP450-expressing cells, nanomolar doses of AFB1-induced DNA adduct formation including AFB1-N7-guanine, -pyrimidyl and -diol adducts. In addition, the T5-1A2 cells showed AFM1-DNA adducts. At similar levels of total DNA adducts, both the T5-1A2 and T5-3A4 cells showed, at codon 249 of the p53 gene, AGG to AGT transversions at a relative frequency of 15x10(-6). In contrast, only the T5-3A4 cells showed CCC to ACC transversion at codon 250 at a high frequency, whereas the second most frequent mutations found in the T5-1A2 cells were C to T transitions at the first and second position of the codon 250. No significant AFB1-induced p53 mutations could be detected in the T5-2A6 cells. Therefore, the differential expression of specific CYP450 genes in human hepatocytes can modulate the cytotoxicity, DNA adduct levels and frequency of p53 mutations produced by AFB1.
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PMID:Aflatoxin B1-induced DNA adduct formation and p53 mutations in CYP450-expressing human liver cell lines. 923 Feb 70

Quetiapine is an atypical antipsychotic used for treatment of schizophrenia. Variability in response to this drug may be associated with pharmacogenetics. The aim of this study was to identify genetic markers related to the pharmacokinetics, pharmacodynamics, and adverse effects of quetiapine. The study population comprised 79 healthy volunteers from two bioequivalence trials who were genotyped to identify polymorphisms in genes encoding enzymes, receptors, and transporters. Quetiapine plasma levels were quantified using high-performance liquid chromatography/mass spectrometry. Prolactin plasma levels were detected by indirect chemiluminescence. Possible adverse effects were recorded throughout the study. Factors with P value of 0.1 or less in the univariate analysis were included in a multiple regression analysis (logistic regression for adverse reactions). The area under the curve and clearance of quetiapine were affected by polymorphisms in CYP1A2 and DRD3, respectively. Men had a lower quetiapine area under the curve compared with women. Prolactin iC(max) was higher in volunteers harboring polymorphisms in CYP2C19 and AGT. An association was detected between polymorphisms in CYP1A1 and CYP2C9 and somnolence. Several polymorphisms are responsible for differences in the pharmacokinetics, pharmacodynamics, and safety of quetiapine in healthy individuals.
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PMID:Pharmacogenetics of quetiapine in healthy volunteers: association with pharmacokinetics, pharmacodynamics, and adverse effects. 2502 89