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Sample records for cyp1a1 gene expression

  1. CYP1A1 and CYP1B1 gene expression and DNA adduct formation in normal human mammary epithelial cells exposed to benzo[a]pyrene in the absence or presence of chlorophyllin.

    PubMed

    John, Kaarthik; Divi, Rao L; Keshava, Channa; Orozco, Christine C; Schockley, Marie E; Richardson, Diana L; Poirier, Miriam C; Nath, Joginder; Weston, Ainsley

    2010-06-28

    Benzo[a]pyrene (BP) is a potent pro-carcinogen and ubiquitous environmental pollutant. Here, we examined the induction and modulation of CYP1A1 and CYP1B1 and 10-(deoxyguanosin-N(2)-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPdG) adduct formation in DNA from 20 primary normal human mammary epithelial cell (NHMEC) strains exposed to BP (4muM) in the absence or presence of chlorophyllin (5muM). Real-time polymerase chain reaction (RT-PCR) analysis revealed strong induction of both CYP1A1 and CYP1B1 by BP, with high levels of inter-individual variability. Variable BPdG formation was found in all strains by r7, t8-dihydroxy-t-9, 10 epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE)-DNA chemiluminescence assay (CIA). Chlorophyllin mitigated BP-induced CYP1A1 and CYP1B1 gene expression in all 20 strains when administered with BP. Chlorophyllin, administered prior to BP-exposure, mitigated CYP1A1 expression in 18/20 NHMEC strains (p<0.005) and CYP1B1 expression in 17/20 NHMEC strains (p<0.005). Maximum percent reductions of CYP1A1 and CYP1B1 gene expression and BPdG adduct formation were observed when cells were pre-dosed with chlorophyllin followed by administration of the carcinogen with chlorophyllin (p<0.005 for CYP1A1 and CYP1B1 expression and p<0.0005 for BPdG adducts). Therefore, chlorophyllin is likely to be a good chemoprotective agent for a large proportion of the human population.

  2. Comparison of microbial hosts and expression systems for mammalian CYP1A1 catalysis.

    PubMed

    Cornelissen, Sjef; Julsing, Mattijs K; Schmid, Andreas; Bühler, Bruno

    2012-02-01

    Mammalian cytochrome P450 enzymes are of special interest as biocatalysts for fine chemical and drug metabolite synthesis. In this study, the potential of different recombinant microorganisms expressing rat and human cyp1a1 genes is evaluated for such applications. The maximum specific activity for 7-ethoxyresorufin O-deethylation and gene expression levels were used as parameters to judge biocatalyst performance. Under comparable conditions, E. coli is shown to be superior over the use of S. cerevisiae and P. putida as hosts for biocatalysis. Of all tested E. coli strains, E. coli DH5α and E. coli JM101 harboring rat CYP1A1 showed the highest activities (0.43 and 0.42 U g⁻¹(CDW), respectively). Detection of active CYP1A1 in cell-free E. coli extracts was found to be difficult and only for E. coli DH5α, expression levels could be determined (41 nmol g⁻¹(CDW)). The presented results show that efficient expression of mammalian cyp1a1 genes in recombinant microorganisms is troublesome and host-dependent and that enhancing expression levels is crucial in order to obtain more efficient biocatalysts. Specific activities currently obtained are not sufficient yet for fine chemical production, but are sufficient for preparative-scale drug metabolite synthesis.

  3. Systemic effects of arctic pollutants in beluga whales indicated by CYP1A1 expression.

    PubMed

    Wilson, Joanna Y; Cooke, Suzy R; Moore, Michael J; Martineau, Daniel; Mikaelian, Igor; Metner, Donald A; Lockhart, W Lyle; Stegeman, John J

    2005-11-01

    Cytochrome P450 1A1 (CYP1A1) is induced by exposure to polycyclic aromatic hydrocarbons (PAHs) and planar halogenated aromatic hydrocarbons (PHAHs) such as non-ortho polychlorinated biphenyls (PCBs). In this study, we examined CYP1A1 protein expression immunohistochemically in multiple organs of beluga whales from two locations in the Arctic and from the St. Lawrence estuary. These beluga populations have some of the lowest (Arctic sites) and highest (St. Lawrence estuary) concentrations of PCBs in blubber of all cetaceans. Samples from these populations might be expected to have different contaminant-induced responses, reflecting their different exposure histories. The pattern and extent of CYP1A1 staining in whales from all three locations were similar to those seen in animal models in which CYP1A has been highly induced, indicating a high-level expression in these whales. CYP1A1 induction has been related to toxic effects of PHAHs or PAHs in some species. In St. Lawrence beluga, the high level of CYP1A1 expression coupled with high levels of contaminants (including CYP1A1 substrates, e.g., PAH procarcinogens potentially activated by CYP1A1) indicates that CYP1A1 could be involved in the development of neoplastic lesions seen in the St. Lawrence beluga population. The systemic high-level expression of CYP1A1 in Arctic beluga suggests that effects of PAHs or PHAHs may be expected in Arctic populations, as well. The high-level expression of CYP1A1 in the Arctic beluga suggests that this species is highly sensitive to CYP1A1 induction by aryl hydrocarbon receptor agonists.

  4. Camel milk modulates the expression of aryl hydrocarbon receptor-regulated genes, Cyp1a1, Nqo1, and Gsta1, in murine hepatoma Hepa 1c1c7 cells.

    PubMed

    Korashy, Hesham M; El Gendy, Mohamed A M; Alhaider, Abdulqader A; El-Kadi, Ayman O

    2012-01-01

    There is a traditional belief in the Middle East that camel milk may aid in prevention and treatment of numerous cases of cancer yet, the exact mechanism was not investigated. Therefore, we examined the ability of camel milk to modulate the expression of a well-known cancer-activating gene, Cytochrome P450 1a1 (Cyp1a1), and cancer-protective genes, NAD(P)H:quinone oxidoreductase 1 (Nqo1) and glutathione S-transferase a1 (Gsta1), in murine hepatoma Hepa 1c1c7 cell line. Our results showed that camel milk significantly inhibited the induction of Cyp1a1 gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most potent Cyp1a1 inducer and known carcinogenic chemical, at mRNA, protein, and activity levels in a concentration-dependent manner. In addition, camel milk significantly decreased the xenobiotic responsive element (XRE)-dependent luciferase activity, suggesting a transcriptional mechanism is involved. Furthermore, this inhibitory effect of camel milk was associated with a proportional increase in heme oxygenase 1. On the other hand, camel milk significantly induced Nqo1 and Gsta1 mRNA expression level in a concentration-dependent fashion. The RNA synthesis inhibitor, actinomycin D, completely blocked the induction of Nqo1 mRNA by camel milk suggesting the requirement of de novo RNA synthesis through a transcriptional mechanism. In conclusion, camel milk modulates the expression of Cyp1a1, Nqo1, and Gsta1 at the transcriptional and posttranscriptional levels.

  5. Profiling deleterious non-synonymous SNPs of smoker's gene CYP1A1.

    PubMed

    Ramesh, A Sai; Khan, Imran; Farhan, Md; Thiagarajan, Padma

    2013-01-01

    CYP1A1 gene belongs to the cytochrome P450 family and is known better as smokers' gene due to its hyperactivation as a consequence of long term smoking. The expression of CYP1A1 induces polycyclic aromatic hydrocarbon production in the lungs, which when over expressed, is known to cause smoking related diseases, such as cardiovascular pathologies, cancer, and diabetes. Single nucleotide polymorphisms (SNPs) are the simplest form of genetic variations that occur at a higher frequency, and are denoted as synonymous and non-synonymous SNPs on the basis of their effects on the amino acids. This study adopts a systematic in silico approach to predict the deleterious SNPs that are associated with disease conditions. It is inferred that four SNPs are highly deleterious, among which the SNP with rs17861094 is commonly predicted to be harmful by all tools. Hydrophobic (isoleucine) to hydrophilic (serine) amino acid variation was observed in the candidate gene. Hence, this investigation aims to characterize a candidate gene from 159 SNPs of CYP1A1.

  6. Functional role and tobacco smoking effects on methylation of CYP1A1 gene in prostate cancer

    PubMed Central

    Kato, Taku; Hashimoto, Yutaka; Yamamura, Soichiro; Fukuhara, Shinichiro; Wong, Darryn K.; Shiina, Marisa; Imai-Sumida, Mitsuho; Majid, Shahana; Saini, Sharanjot; Shiina, Hiroaki; Nakajima, Koichi; Deng, Guoren; Dahiya, Rajvir; Tanaka, Yuichiro

    2016-01-01

    Cytochrome P450 (CYP) 1A1 is a phase I enzyme that can activate various compounds into reactive forms and thus, may contribute to carcinogenesis. In this study, we investigated the expression, methylation status, and functional role of CYP1A1 on prostate cancer cells. Increased expression of CYP1A1 was observed in all cancer lines (PC-3, LNCaP, and DU145) compared to BPH-1 (P < 0.05); and was enhanced further by 5-aza-2′-deoxycytidine treatment (P < 0.01). Methylation-specific PCR (MSP) and sequencing of bisulfite-modified DNA of the xenobiotic response element (XRE) enhancer site XRE-1383 indicated promoter methylation as a regulator of CYP1A1 expression. In tissue, microarrays showed higher immunostaining of CYP1A1 in prostate cancer than normal and benign prostatic hyperplasia (BPH; P < 0.001), and methylation analyses in clinical specimens revealed significantly lower methylation levels in cancer compared to BPH at all enhancer sites analyzed (XRE-1383, XRE-983, XRE-895; P < 0.01). Interestingly, smoking affected the XRE-1383 site where the methylation level was much lower in cancer tissues from smokers than non-smokers (P < 0.05). CYP1A1 levels are thus increased in prostate cancer and to determine the functional effect of CYP1A1 on cells, we depleted the gene in LNCaP and DU145 by siRNA. We observe that CYP1A1 knockdown decreased cell proliferation (P < 0.05) and increased apoptosis (P < 0.01) in both cell lines. We analyzed genes affected by CYP1A1 silencing and found that apoptosis-related BCL2 was significantly down-regulated. This study supports an oncogenic role for CYP1A1 in prostate cancer via promoter hypomethylation that is influenced by tobacco smoking, indicating CYP1A1 to be a promising target for prostate cancer treatment. PMID:27203547

  7. Effects of β-glucan extracted from Agaricus blazei on the expression of ERCC5, CASP9, and CYP1A1 genes and metabolic profile in HepG2 cells.

    PubMed

    da Silva, A F; Sartori, D; Macedo, F C; Ribeiro, L R; Fungaro, M H P; Mantovani, M S

    2013-06-01

    The polysaccharide β-glucan has biological properties that stimulate the immune system and can prevent chronic pathologies, including cancer. It has been shown to prevent damage to DNA caused by the chemical and physical agents to which humans are exposed. However, the mechanism of β-glucan remains poorly understood. The objective of the present study was to verify the protective effect of β-glucan on the expression of the genes ERCC5 (involved in excision repair of DNA damage), CASP9 (involved in apoptosis), and CYP1A1 (involved in the metabolism of xenobiotics) using real-time polymerase chain reaction and perform metabolic profile measurements on the HepG2 cells. Cells were exposed to only benzo[a]pyrene (B[a]P), β-glucan, or a combination of B[a]P with β-glucan. The results demonstrated that 50 µg/mL β-glucan significantly repressed the expression of the ERCC5 gene when compared with the untreated control cells in these conditions. No change was found in the CASP9 transcript level. However, the CYP1A1 gene expression was also induced by HepG2 cells exposed to B[a]P only or in association with β-glucan, showing its effective protector against damage caused by B[a]P, while HepG2 cells exposed to only β-glucan did not show CYP1A1 modulation. The metabolic profiles showed moderate bioenergetic metabolism with an increase in the metabolites involved in bioenergetic metabolism (alanine, glutamate, creatine and phosphocholine) in cells treated with β-glucan and to a lesser extent treated with B[a]P. Thus, these results demonstrate that the chemopreventive activity of β-glucan may modulate bioenergetic metabolism and gene expression.

  8. PPARalpha activation potentiates AhR-induced CYP1A1 expression.

    PubMed

    Fallone, Frédérique; Villard, Pierre-Henri; Decome, Laetitia; Sérée, Eric; Méo, Michel de; Chacon, Christine; Durand, Alain; Barra, Yves; Lacarelle, Bruno

    2005-12-15

    CYP1A1 is an extrahepatic enzyme largely involved in the bioactivation of various procarcinogens such as polycyclic aromatic hydrocarbons (PAHs) and arylamines. CYP1A1 expression is mainly regulated by AhR. Our laboratory has recently shown a new CYP1A1 regulation pathway involving PPARalpha. The aim of this study was to evaluate, in a Caco-2 cell line, the effect of a coexposure to 3-methylcholanthrene (3MC, AhR ligand) and WY-14643 (WY, PPARalpha ligand) on CYP1A1 expression (enzymatic activity, mRNA level and promoter activity). An additive effect on CYP1A1 expression was shown in cells coexposed with 3MC (0.1 or 1 microM) and a low WY concentration (30 microM) whereas a potentiating effect was observed after coexposure with 3MC (0.1 or 1 microM) and a high WY concentration (200 microM). Furthermore, 200 microM WY, alone or with 3MC, was able to increase the AhR protein level (two-fold). In conclusion, coexposure with 3MC and the PPARalpha agonist WY leads to an additive or potentiating effect on CYP1A1 inducibility, depending on the WY concentration. Furthermore, at high concentration (200 microM), WY induced AhR expression, which could explain the potentiating effect on CYP1A1 inducibility observed after addition of an AhR ligand (3MC). This phenomenon should be taken into account for risk assessment involving CYP1A1 induction.

  9. Effect of polyunsaturated fatty acids ω-3 on the induction of activity and expression of CYP1A1 and CYP1A2 genes in the liver of rats under the influence of indole-3-carbinol.

    PubMed

    Kravchenko, L V; Tutel'yan, V A; Trusov, N V; Guseva, G V; Aksenov, I V

    2014-01-01

    Supplementation of the ration with eicosapentaenoic and docosahexaenoic ω-3 polyunsaturated fatty acids (PUFA) in doses of 0.3 and 1 g/kg body weight for 4 weeks had no effect on ethoxyresorufin O-dealkylase (EROD) activity and expression of the CYP1A1 gene in male Wistar rats, but caused a dose-dependent increase in methoxyresorufin O-dealkylase (MROD) activity of CYP1A2 (by 28 and 73%, respectively) without significant changes in CYP1A2 mRNA expression. ω-3 PUFA had no effect on the indole-3-carbinol-induced (20 mg/kg body weight over the last 7 days of the experiment) EROD activity and expression of CYP1A1 mRNA. The indole-3-carbinol-induced MROD activity was shown to increase by 6.2 times in rats not receiving ω-3 PUFA and only by 3.9 and 2.7 times in animals receiving ω-3 PUFA. The indole-3-carbinol-induced expression of CYP1A2 mRNA slightly increased in animals receiving ω-3 PUFA. Our results suggest that the effect of ω-3 PUFA on the induced and basal activity of CYP1A2 is not related to modulation of CYP1A2 gene expression.

  10. Transgenic rice plants expressing human CYP1A1 remediate the triazine herbicides atrazine and simazine.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2005-11-02

    The human cytochrome P450 CYP1A1 gene was introduced into rice plants (Oryza sativa cv. Nipponbare). One-month-old CYP1A1 plants grown in soil clearly showed a healthy growth and tolerance to 8.8 microM atrazine and 50 microM simazine, but nontransgenic plants were completely killed by the herbicides. Although transgenic and nontransgenic plants metabolized the two herbicides into the same sets of compounds, CYP1A1 plants metabolized atrazine and simazine more rapidly than did control plants. In small-scale experiments, residual amounts of atrazine and simazine in the culture medium of CYP1A1 plants were 43.4 and 12.3% of those in control medium; those of nontransgenic Nipponbare were 68.3 and 57.2%, respectively. When cultivated in soil with 2.95 microM atrazine and 3.15 microM simazine for 25 days, CYP1A1 plants eliminated 1.3 times more atrazine and 1.4 times more simazine from the soil than did control plants. Thus, CYP1A1 rice plants make it possible to remove atrazine and simazine more rapidly from the culture medium and soil than can nontransgenic Nipponbare.

  11. Omeprazole transactivates human CYP1A1 and CYP1A2 expression through the common regulatory region containing multiple xenobiotic-responsive elements.

    PubMed

    Yoshinari, Kouichi; Ueda, Rika; Kusano, Kazutomi; Yoshimura, Tsutomu; Nagata, Kiyoshi; Yamazoe, Yasushi

    2008-07-01

    Omeprazole induces human CYP1A1 and CYP1A2 in human hepatoma cells and human liver. Aryl hydrocarbon receptor (AHR) is shown to be involved in this induction. However, its precise molecular mechanism remains unknown because the chemical activates AHR without its direct binding in contrast to typical AHR ligands such as 3-methylcholanthrene (3MC) and beta-naphthoflavone (BNF). Human CYP1A1 and CYP1A2 genes are located in a head-to-head orientation sharing about 23 kb 5'-flanking region. Recently, we succeeded to measure CYP1A1 and CYP1A2 transcriptional activities simultaneously using dual reporter gene constructs containing the 23 kb sequence. In this study, transient transfection assays have been performed using numbers of single and dual reporter constructs to identify omeprazole-responsive region for CYP1A1 and CYP1A2 induction. Reporter assays with deletion constructs have demonstrated that the omeprazole-induced expression of both CYP1A1 and CYP1A2 is mediated via the common regulatory region containing multiple AHR-binding motifs (the nucleotides from -464 to -1829 of human CYP1A1), which is identical with the region for BNF and 3MC induction. Interestingly, omeprazole activated the transcription of CYP1A1 and CYP1A2 to similar extents while BNF and 3MC preferred CYP1A1 expression. We have also found that primaquine is an omeprazole-like CYP1A inducer, while lansoprazole and albendazole are 3MC/BNF-like in terms of the CYP1A1/CYP1A2 preference. The present results suggest that omeprazole as well as BNF and 3MC activates both human CYP1A1 and CYP1A2 expression through the common regulatory region despite that omeprazole may involve a different cellular signal(s) from BNF and 3MC.

  12. Herbicide resistance of transgenic rice plants expressing human CYP1A1.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2007-01-01

    Cytochrome P450 monooxygenases (P450s) metabolize herbicides to produce mainly non-phytotoxic metabolites. Although rice plants endogenously express multiple P450 enzymes, transgenic plants expressing other P450 isoforms might show improved herbicide resistance or reduce herbicide residues. Mammalian P450s metabolizing xenobiotics are reported to show a broad and overlapping substrate specificity towards lipophilic foreign chemicals, including herbicides. These P450s are ideal for enhancing xenobiotic metabolism in plants. A human P450, CYP1A1, metabolizes various herbicides with different structures and modes of herbicide action. We introduced human CYP1A1 into rice plants, and the transgenic rice plants showed broad cross-resistance towards various herbicides and metabolized them. The introduced CYP1A1 enhanced the metabolism of chlorotoluron and norflurazon. The herbicides were metabolized more rapidly in the transgenic rice plants than in non-transgenic controls. Transgenic rice plants expressing P450 might be useful for reducing concentrations of various chemicals in the environment.

  13. Metformin suppresses CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating aryl hydrocarbon receptor expression

    SciTech Connect

    Do, Minh Truong; Kim, Hyung Gyun; Tran, Thi Thu Phuong; Khanal, Tilak; Choi, Jae Ho; Chung, Young Chul; Jeong, Tae Cheon; Jeong, Hye Gwang

    2014-10-01

    Induction of cytochrome P450 (CYP) 1A1 and CYP1B1 by environmental xenobiotic chemicals or endogenous ligands through the activation of the aryl hydrocarbon receptor (AhR) has been implicated in a variety of cellular processes related to cancer, such as transformation and tumorigenesis. Here, we investigated the effects of the anti-diabetes drug metformin on expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and inducible conditions. Our results indicated that metformin down-regulated the expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced conditions. Down-regulation of AhR expression was required for metformin-mediated decreases in CYP1A1 and CYP1B1 expression, and the metformin-mediated CYP1A1 and CYP1B1 reduction is irrelevant to estrogen receptor α (ERα) signaling. Furthermore, we found that metformin markedly down-regulated Sp1 protein levels in breast cancer cells. The use of genetic and pharmacological tools revealed that metformin-mediated down-regulation of AhR expression was mediated through the reduction of Sp1 protein. Metformin inhibited endogenous AhR ligand-induced CYP1A1 and CYP1B1 expression by suppressing tryptophan-2,3-dioxygenase (TDO) expression in MCF-7 cells. Finally, metformin inhibits TDO expression through a down-regulation of Sp1 and glucocorticoid receptor (GR) protein levels. Our findings demonstrate that metformin reduces CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating AhR signaling. Metformin would be able to act as a potential chemopreventive agent against CYP1A1 and CYP1B1-mediated carcinogenesis and development of cancer. - Graphical abstract: Schematic of the CYP1A1 and CYP1B1 gene regulation by metformin. - Highlights: • Metformin inhibits CYP1A1 and CYP1B1 expression. • Metformin down-regulates the AhR signaling. • Metformin reduces Sp1 protein expression. • Metformin suppresses TDO expression.

  14. Constitutive androstane receptor transcriptionally activates human CYP1A1 and CYP1A2 genes through a common regulatory element in the 5'-flanking region.

    PubMed

    Yoshinari, Kouichi; Yoda, Noriaki; Toriyabe, Takayoshi; Yamazoe, Yasushi

    2010-01-15

    Phenobarbital has long been known to increase cellular levels of CYP1A1 and CYP1A2 possibly through a pathway(s) independent of aryl hydrocarbon receptor. We have investigated the role of constitutive androstane receptor (CAR), a xenobiotic-responsive nuclear receptor, in the transactivation of human CYP1A1 and CYP1A2. These genes are located in a head-to-head orientation, sharing a 5'-flanking region. Reporter assays were thus performed with dual-reporter constructs, containing the whole or partially deleted human CYP1A promoter between two different reporter genes. In this system, human CAR (hCAR) enhanced the transcription of both genes through common promoter regions from -461 to -554 and from -18089 to -21975 of CYP1A1. With reporter assays using additional deleted and mutated constructs, electrophoresis mobility shift assays and chromatin immunoprecipitation assays, an ER8 motif (everted repeat separated by eight nucleotides), located at around -520 of CYP1A1, was identified as an hCAR-responsive element and a binding motif of hCAR/human retinoid X receptor alpha heterodimer. hCAR enhanced the transcription of both genes also in the presence of an aryl hydrocarbon receptor ligand. Finally, hCAR activation increased CYP1A1 and CYP1A2 mRNA levels in cultured human hepatocytes. Our results indicate that CAR transactivates human CYP1A1 and CYP1A2 in human hepatocytes through the common cis-element ER8. Interestingly, the ER8 motif is highly conserved in the CYP1A1 proximal promoter sequences of various species, suggesting a fundamental role of CAR in the xenobiotic-induced expression of CYP1A1 and CYP1A2 independent of aryl hydrocarbon receptor.

  15. Strong synergistic induction of CYP1A1 expression by andrographolide plus typical CYP1A inducers in mouse hepatocytes

    SciTech Connect

    Jaruchotikamol, Atika; Jarukamjorn, Kanokwan Sirisangtrakul, Wanna; Sakuma, Tsutomu; Kawasaki, Yuki; Nemoto, Nobuo

    2007-10-15

    The effects of andrographolide, the major diterpenoid constituent of Andrographis paniculata, on the expression of cytochrome P450 superfamily 1 members, including CYP1A1, CYP1A2, and CYP1B1, as well as on aryl hydrocarbon receptor (AhR) expression in primary cultures of mouse hepatocytes were investigated in comparison with the effects of typical CYP1A inducers, including benz[a]anthracene, {beta}-naphthoflavone, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. Andrographolide significantly induced the expression of CYP1A1 and CYP1A2 mRNAs in a concentration-dependent manner, as did the typical CYP1A inducers, but did not induce that of CYP1B1 or AhR. Interestingly, andrographolide plus the typical CYP1A inducers synergistically induced CYP1A1 expression, and the synergism was blocked by an AhR antagonist, resveratrol. The CYP1A1 enzyme activity showed a similar pattern of induction. This is the first report that shows that andrographolide has a potency to induce CYP1A1 enzyme and indicates that andrographolide could be a very useful compound for investigating the regulatory mechanism of the CYP1A1 induction pathway. In addition, our findings suggest preparing advice for rational administration of A. paniculata, according to its ability to induce CYP1A1 expression.

  16. Interaction of the CYP1A1 gene polymorphism and smoking in non-small cell lung cancer susceptibility.

    PubMed

    Xie, Y Q; Chen, J M; Liu, Y

    2016-01-04

    Many studies have shown that genetic factors, environmental factors, and bad living habits, especially smoking, are risk factors for lung cancer. However, not all smokers develop lung cancer, which may be related to different genetic backgrounds. Currently, most research has investigated the GSTM1, XRCC1, XRCC3, CYP2D6, and C188T genes. Little research has been done on the cytochrome P450 (CYP) 1A1 gene, and results have varied. In addition, no results have been reported on the interactive effects of smoking and the CYP1A1 gene on lung cancer development. We used polymerase chain reaction restriction fragment length polymorphism to detect the CYP1A1 genotype, and investigate the effects of the CYP1A1 gene deletion and smoking alone, and in combination, on non-small cell lung cancer susceptibility. We enrolled 150 non-small cell lung cancer patients and 150 healthy control subjects. Subjects' smoking habits and CYP1A1 gene polymorphism were analyzed to investigate their role in the occurrence of lung cancer. The CYP1A1 gene deletion was found in 73.3% of non-small cell lung cancer patients and 20.0% of healthy subjects. The OR value was 2.28 (P < 0.05). Among smoking subjects, 77.8% exhibited non-small cell lung cancer, significantly higher than the 27.3% in non-smokers (P < 0.05). The OR value for the interaction of smoking and CYP1A1 gene deletion was 5.60, larger than the product of their individual OR values. The CYP1A1 gene deletion is a lung cancer risk factor, and interacts with smoking in non-small cell lung cancer development.

  17. Mice Deficient in the Gene for Cytochrome P450 (CYP)1A1 Are More Susceptible Than Wild-Type to Hyperoxic Lung Injury: Evidence for Protective Role of CYP1A1 Against Oxidative Stress

    PubMed Central

    Wang, Lihua; Wang, Gangduo; Couroucli, Xanthi I.; Shivanna, Binoy; Welty, Stephen E.; Barrios, Roberto; Khan,  M. Firoze; Nebert, Daniel W.; Roberts, L. Jackson; Moorthy, Bhagavatula

    2014-01-01

    Hyperoxia contributes to acute lung injury in diseases such as acute respiratory distress syndrome in adults and bronchopulmonary dysplasia in premature infants. Cytochrome P450 (CYP)1A1 has been shown to modulate hyperoxic lung injury. The mechanistic role(s) of CYP1A1 in hyperoxic lung injury in vivo is not known. In this investigation, we hypothesized that Cyp1a1(–/–) mice would be more susceptible to hyperoxic lung injury than wild-type (WT) mice, and that the protective role of CYP1A1 is in part due to CYP1A1-mediated decrease in the levels of reactive oxygen species-mediated lipid hydroperoxides, e.g., F2-isoprostanes/isofurans, leading to attenuation of oxidative damage. Eight- to ten-week-old male WT (C57BL/6J) or Cyp1a1(–/–) mice were exposed to hyperoxia (>95% O2) or room air for 24–72 h. The Cyp1a1(–/–) mice were more susceptible to oxygen-mediated lung damage and inflammation than WT mice, as evidenced by increased lung weight/body weight ratio, lung injury, neutrophil infiltration, and augmented expression of IL-6. Hyperoxia for 24–48 h induced CYP1A expression at the mRNA, protein, and enzyme levels in liver and lung of WT mice. Pulmonary F2-isoprostane and isofuran levels were elevated in WT mice after hyperoxia for 24 h. On the other hand, Cyp1a1(–/–) mice showed higher levels after 48–72 h of hyperoxia exposure compared to WT mice. Our results support the hypothesis that CYP1A1 protects against hyperoxic lung injury by decreasing oxidative stress. Future research could lead to the development of novel strategies for prevention and/or treatment of acute lung injury. PMID:24893714

  18. Respirable coal dust particles modify cytochrome P4501A1 (CYP1A1) expression in rat alveolar cells.

    PubMed

    Ghanem, Mohamed M; Porter, Dale; Battelli, Lori A; Vallyathan, Val; Kashon, Michael L; Ma, Jane Y; Barger, Mark W; Nath, Joginder; Castranova, Vincent; Hubbs, Ann F

    2004-08-01

    Cytochrome P4501A1 (CYP1A1) metabolizes polycyclic aromatic hydrocarbons in cigarette smoke to DNA-binding reactive intermediates associated with carcinogenesis. Epidemiologic studies indicate that the majority of coal miners are smokers but have a lower risk of lung cancer than other smokers. We hypothesized that coal dust (CD) exposure modifies pulmonary carcinogenesis by altering CYP1A1 induction. Therefore, male Sprague Dawley rats were intratracheally instilled with 2.5, 10, 20, or 40 mg CD/rat or vehicle (saline); and 11 d later, pulmonary CYP1A1 was induced by intraperitoneal injection of beta-naphthoflavone (BNF; 50 mg/kg). Fourteen days after CD exposure, CYP1A1 protein and activity were measured by Western blot and 7-ethoxyresorufin-O-deethylase activity, respectively. CYP1A1 and the alveolar type II markers, cytokeratins 8/18, were localized and quantified in lung sections by dual immunofluorescence with morphometry. The area of CYP1A1 expression in alveolar septa and alveolar type II cells in response to BNF was reduced by exposure to 20 or 40 mg CD compared with BNF alone. CD exposure significantly inhibited BNF-induced 7-ethoxyresorufin-O-deethylase activity in a dose-responsive manner. By Western blot, induction of CYP1A1 protein by BNF was significantly reduced by 40 mg CD compared with BNF alone. These findings indicate that CD decreases BNF-induced CYP1A1 protein expression and activity in the lung.

  19. Nuclear transcription factor Oct-1 binds to the 5'-upstream region of CYP1A1 and negatively regulates its expression.

    PubMed

    Bhat, R; Weaver, J A; Sterling, K M; Bresnick, E

    1996-02-01

    The cytochrome P450-dependent monooxygenases, which represent an extended superfamily, catalyze the biotransformation of many endogenous and exogenous substances. One of these hemoproteins, cytochrome P4501A1, is most closely associated with the bioactivation of polycyclic aromatic hydrocarbons such as benzo[a]pyrene, which may play a role in environmental carcinogenesis. A negative regulatory element (NRE) has been localized in the 5'-upstream region of the cytochrome P4501A1 gene (CYP1A1) at -843 to -746 base pairs from the site of transcription. The purpose of this research was to define any interactions of trans-acting proteins with this cis element. Rat liver nuclei were used as the source of trans-acting proteins and a biotinylated NRE-bearing fragment (-782 to -843 bp) from a plasmid which contained the CYP1A1 was prepared by the polymerase chain reaction technique. Gel mobility shift assays were used to demonstrate interactions between this NRE fragment and nuclear proteins. The specific binding to an octamer-containing motif in the 5'-upstream region of CYP1A1 was demonstrated; this was used as a step in the partial purification from rat liver of the transcription factor, Oct-1. Conventional chromatographic procedures and DNA recognition site affinity chromatography were also used. HepG2 human hepatoma cells were transfected with both pMCoLUC+ which contains the luciferase gene as a reporter gene driven by the CYP1A1 promoter (including the NRE), and an Oct-1 expression vector. Luciferase activity/mg protein in the doubly-transfected cells was significantly lower than in cells containing only pMCoLUC+. A nuclear transcription factor Oct-1 interacts with a portion of the NRE of the rat CYP1A1, suppressing the expression of this gene. These findings may help to explain the low level of basal expression of CYP1A1 in mammalian systems.

  20. Differential effect of over-expressing UGT1A1 and CYP1A1 on xenobiotic assault in MCF-7 cells.

    PubMed

    Leung, Hau Y; Wang, Yun; Leung, Lai K

    2007-12-05

    Gene mutation has been considered as a major step of carcinogenesis. Some defective genes may induce spontaneous tumorigenesis, while others are required to interact with the environment to induce cancer. CYP1A1 and UGT1A1 are encoded for the respective phase I and II drug-metabolizing enzymes. Their expressions have been associated with breast cancer incidence in women, and some xenobiotics are substrates of these two enzymes. In the current study, cytochrome P450 (CYP) 1A1 and UDP-glucuronosyltransferase (UGT) 1A1 were over-expressed in the breast cancer MCF-7 cells, and potential interactions between these enzymes and estrogen or polycyclic aromatic hydrocarbon were evaluated. Compared with control cells (MCF-7(VEC)), reduced cell proliferation was seen in cells expressing UGT1A1 (MCF-7(UGT1A1)) under estradiol treatment. 7,12-Dimethylbenz[a]anthracene (DMBA) is an established breast cancer initiator in animal model. Over-expressing UGT1A1 reduced the binding of DMBA to DNA, and increased MCF-7(UGT1A1) intact cells under DMBA treatment was verified by comet assay. On the other hand, intensified DMBA binding and damages were observed in MCF-7(CYP1A1) cells. This study supported that UGT1A1 but not CYP1A1 expression could protect against xenobiotic assault.

  1. Effects of artificial sweeteners on the AhR- and GR-dependent CYP1A1 expression in primary human hepatocytes and human cancer cells.

    PubMed

    Kamenickova, Alzbeta; Pecova, Michaela; Bachleda, Petr; Dvorak, Zdenek

    2013-12-01

    Food constituents may cause a phenomenon of food-drug interactions. In the current study, we examined the effects of artificial sweeteners (aspartame, acesulfame, cyclamate, saccharin) on the aryl hydrocarbon receptor (AhR) and glucocorticoid receptor (GR)-dependent expression of CYP1A1 in human hepatocytes, hepatic HepG2 and intestinal LS174T cancer cell lines. Sweeteners were tested in concentrations up to those occurring in non-alcoholic beverages. Basal and ligand-inducible AhR- and GR-dependent reporter gene activation in stably transfected HepG2 and HeLa cells, respectively, were not affected by either of the sweeteners tested after 24h of incubation. The expression of CYP1A1 mRNA and protein in primary cultures of human hepatocytes and in LS174T and HepG2 cells was not induced by any of the tested sweeteners. Overall, aspartame, acesulfame, saccharin and cyclamate had no effects on CYP1A1 expression and transcriptional activities of AhR and GR. These data imply the safety of artificial sweeteners in terms of interference with AhR, GR and CYP1A1.

  2. Expression Profile of CYP1A1 and CYP1B1 Enzymes in Colon and Bladder Tumors

    PubMed Central

    Androutsopoulos, Vasilis P.; Spyrou, Ioannis; Ploumidis, Achilles; Papalampros, Alexandros Eystathios; Kyriakakis, Michalis; Delakas, Demetrios; Spandidos, Demetrios A.; Tsatsakis, Aristidis M.

    2013-01-01

    Background The cytochrome P450 CYP1A1 and CYP1B1 enzymes are involved in carcinogenesis via activation of pro-carcinogenic compounds to carcinogenic metabolites. CYP1A1 and CYP1B1 have shown elevated levels in human tumors as determined by qRT-PCR and immunohistochemical studies. However studies that have examined CYP1 expression by enzyme activity assays are limited. Results In the current study the expression of CYP1A1 and CYP1B1 was investigated in a panel of human tumors of bladder and colorectal origin by qRT-PCR and enzyme activity assays. The results demonstrated that 35% (7/20) of bladder tumors and 35% (7/20) of colon tumors overexpressed active CYP1 enzymes. CYP1B1 mRNA was overexpressed in 65% and 60% of bladder and colon tumors respectively, whereas CYP1A1 was overexpressed in 65% and 80% of bladder and colon tumors. Mean mRNA levels of CYP1B1 and CYP1A1 along with mean CYP1 activity were higher in bladder and colon tumors compared to normal tissues (p<0.05). Statistical analysis revealed CYP1 expression levels to be independent of TNM status. Moreover, incubation of tumor microsomal protein in 4 bladder and 3 colon samples with a CYP1B1 specific antibody revealed a large reduction (72.5 ± 5.5 % for bladder and 71.8 ± 7.2% for colon) in catalytic activity, indicating that the activity was mainly attributed to CYP1B1 expression. Conclusions The study reveals active CYP1 overexpression in human tumors and uncovers the potential use of CYP1 enzymes and mainly CYP1B1 as targets for cancer therapy. PMID:24358191

  3. Dioxin-dependent activation of murine Cyp1a-1 gene transcription requires protein kinase C-dependent phosphorylation.

    PubMed Central

    Carrier, F; Owens, R A; Nebert, D W; Puga, A

    1992-01-01

    Transcriptional activation of the murine Cyp1a-1 (cytochrome P(1)450) gene by inducers such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (dioxin) requires the aromatic hydrocarbon (Ah) receptor and the interaction of an inducer-receptor complex with one or more of the Ah-responsive elements (AhREs) located about 1 kb upstream from the transcriptional initiation site. We find that treatment of mouse hepatoma Hepa-1 cells with 2-aminopurine, an inhibitor of protein kinase activity, inhibits CYP1A1 mRNA induction by TCDD as well as the concomitant increase in CYP1A1 enzyme activity. Formation of DNA-protein complexes between the Ah receptor and its AhRE target is also inhibited by 2-aminopurine, as determined by gel mobility shift assays. Phosphorylation is required for the formation of Ah receptor-specific complexes, since in vitro dephosphorylation of nuclear extracts from TCDD-treated Hepa-1 cells abolishes the capacity of the Ah receptor to form specific complexes with its cognate AhRE sequences. To determine whether any one of several known protein kinases was involved in the transcriptional regulation of the Cyp1a-1 gene, we treated Hepa-1 cells with nine other protein kinase inhibitors prior to induction with TCDD; nuclear extracts from these cells were analyzed for their capacity to form specific DNA-protein complexes. Only extracts from cells treated with staurosporine, a protein kinase C inhibitor, were unable to form these complexes. In addition, staurosporine completely inhibited CYP1A1 mRNA induction by TCDD. Depletion of protein kinase C by prolonged treatment with phorbol ester led to the complete suppression of CYP1A1 mRNA induction by TCDD. We conclude that (i) phosphorylation is necessary for the formation of a transcriptional complex and for transcriptional activation of the Cyp1a-1 gene; (ii) the phosphorylation site(s) exists on at least one of the proteins constituting the transcriptional complex, possibly the Ah receptor itself; and (iii) the

  4. Functional evaluation of novel single nucleotide polymorphisms and haplotypes in the promoter regions of CYP1B1 and CYP1A1 genes.

    PubMed

    Han, Weiguo; Pentecost, Brian T; Spivack, Simon D

    2003-07-01

    Interindividual variation in the expression of the carcinogen- and estrogen-metabolizing enzymes cytochrome P4501B1 and 1A1 (CYP1B1 and CYP1A1) has been detected in human lung. To search for polymorphisms with functional consequences for CYP1B1 and CYP1A1 gene expression, we examined 1.5 kb of the promoter region of each gene. Genomic DNA from 21 Caucasian individuals was amplified by polymerase chain reaction (PCR) for direct cycle sequencing. Eight single nucleotide polymorphisms (SNPs) for CYP1B1 and 13 SNPs for CYP1A1 were found. The majority of polymorphisms occurred as multiSNP combinations for individual subjects. The wild-type sequences were cloned into a luciferase reporter construct. The most frequent polymorphisms were then recreated by iterative site-directed mutagenesis, replicating single polymorphisms and multiSNP combinations. These wild-type and variant constructs were functionally evaluated in transient transfection experiments employing exposures to either the index polycyclic aromatic hydrocarbon (PAH) inducer benzo[a]pyrene (B[a]P), a composite mixture of cigarette smoke extract (CSE), or the repressor chemopreventive agent trans-3,4,5-trihydroxystilbene (reseveratrol). Results indicated that all wild-type and variant constructs responded in qualitatively concordant fashion to the inducers and to the repressor. The CYP1B1 haplotypes and the majority of CYP1A1 haplotypes were shown to have no functional consequence, as compared to those of the wild-type promoter sequences. Two constructs of composite polymorphisms of CYP1A1 appeared to result in a statistically significant increase in basal promoter activity (1.38- and 1.50-fold, respectively), but the degree of functional impact was judged unlikely to be biologically important in vivo. We conclude that the observed promoter region polymorphisms in these genes are common, but are of unclear functional consequence.

  5. Skatole (3-Methylindole) Is a Partial Aryl Hydrocarbon Receptor Agonist and Induces CYP1A1/2 and CYP1B1 Expression in Primary Human Hepatocytes

    PubMed Central

    Balaguer, Patrick; Ekstrand, Bo; Daujat-Chavanieu, Martine; Gerbal-Chaloin, Sabine

    2016-01-01

    Skatole (3-methylindole) is a product of bacterial fermentation of tryptophan in the intestine. A significant amount of skatole can also be inhaled during cigarette smoking. Skatole is a pulmonary toxin that induces the expression of aryl hydrocarbon receptor (AhR) regulated genes, such as cytochrome P450 1A1 (CYP1A1), in human bronchial cells. The liver has a high metabolic capacity for skatole and is the first organ encountered by the absorbed skatole; however, the effect of skatole in the liver is unknown. Therefore, we investigated the impact of skatole on hepatic AhR activity and AhR-regulated gene expression. Using reporter gene assays, we showed that skatole activates AhR and that this is accompanied by an increase of CYP1A1, CYP1A2 and CYP1B1 expression in HepG2-C3 and primary human hepatocytes. Specific AhR antagonists and siRNA-mediated AhR silencing demonstrated that skatole-induced CYP1A1 expression is dependent on AhR activation. The effect of skatole was reduced by blocking intrinsic cytochrome P450 activity and indole-3-carbinole, a known skatole metabolite, was a more potent inducer than skatole. Finally, skatole could reduce TCDD-induced CYP1A1 expression, suggesting that skatole is a partial AhR agonist. In conclusion, our findings suggest that skatole and its metabolites affect liver homeostasis by modulating the AhR pathway. PMID:27138278

  6. Polymorphic variation of CYP1A1 and CYP1B1 genes in a Haryana population.

    PubMed

    Giri, Shiv Kumar; Yadav, Anita; Kumar, Anil; Dev, Kapil; Gulati, Sachin; Gupta, Ranjan; Aggarwal, Neeraj; Gautam, Sanjeev Kumar

    2013-12-01

    Cytochrome P450 (CYP) 1A1 and CYP1B1 are important phase I xenobiotic metabolizing enzymes involved in the metabolism of numbers of toxins, endogenous hormones, and pharmaceutical drugs. Polymorphisms in these phase I genes can alter enzyme activity and are known to be associated with cancer susceptibility related to environmental toxins and hormone exposure. Their genotypes may also display ethnicity-dependent population frequencies. The present study was aimed to determine the frequencies of commonly known functional polymorphisms of CYP1A1 and CYP1B1 genes in a Haryana state population of North India. The allelic frequency of CYP1A1 polymorphism m1 (MspI) was 29.65% and m2 (Ile(462)Val) was 24.85%. The frequency of CYP1B1 polymorphism m1 (Val(432)Leu) was 45.85% and m2 (Asn(453)Ser) was 16.2%. We observed inter- and intra-ethnic variation in the frequency distribution of these polymorphisms. Analysis of polymorphisms in these genes might help in predicting the risk of cancer. Our results emphasize the need for more such studies in high-risk populations.

  7. CYP1A1 and CYP1A2 expression: Comparing 'humanized' mouse lines and wild-type mice; comparing human and mouse hepatoma-derived cell lines

    SciTech Connect

    Uno, Shigeyuki; Endo, Kaori; Ishida, Yuji; Tateno, Chise; Makishima, Makoto; Yoshizato, Katsutoshi; Nebert, Daniel W.

    2009-05-15

    Human and rodent cytochrome P450 (CYP) enzymes sometimes exhibit striking species-specific differences in substrate preference and rate of metabolism. Human risk assessment of CYP substrates might therefore best be evaluated in the intact mouse by replacing mouse Cyp genes with human CYP orthologs; however, how 'human-like' can human gene expression be expected in mouse tissues? Previously a bacterial-artificial-chromosome-transgenic mouse, carrying the human CYP1A1{sub C}YP1A2 locus and lacking the mouse Cyp1a1 and Cyp1a2 orthologs, was shown to express robustly human dioxin-inducible CYP1A1 and basal versus inducible CYP1A2 (mRNAs, proteins, enzyme activities) in each of nine mouse tissues examined. Chimeric mice carrying humanized liver have also been generated, by transplanting human hepatocytes into a urokinase-type plasminogen activator(+/+){sub s}evere-combined-immunodeficiency (uPA/SCID) line with most of its mouse hepatocytes ablated. Herein we compare basal and dioxin-induced CYP1A mRNA copy numbers, protein levels, and four enzymes (benzo[a]pyrene hydroxylase, ethoxyresorufin O-deethylase, acetanilide 4-hydroxylase, methoxyresorufin O-demethylase) in liver of these two humanized mouse lines versus wild-type mice; we also compare these same parameters in mouse Hepa-1c1c7 and human HepG2 hepatoma-derived established cell lines. Most strikingly, mouse liver CYP1A1-specific enzyme activities are between 38- and 170-fold higher than human CYP1A1-specific enzyme activities (per unit of mRNA), whereas mouse versus human CYP1A2 enzyme activities (per unit of mRNA) are within 2.5-fold of one another. Moreover, both the mouse and human hepatoma cell lines exhibit striking differences in CYP1A mRNA levels and enzyme activities. These findings are relevant to risk assessment involving human CYP1A1 and CYP1A2 substrates, when administered to mice as environmental toxicants or drugs.

  8. Suppressive effects of alpha-Hederin on 2,3,7,8-tetrachlorodibenzo-p-dioxin-mediated murine Cyp1a-1 expression in the mouse hepatoma Hepa-1c1c7 cells.

    PubMed

    Jeong, H G; Lee, S S

    1999-04-26

    Cultured mouse hepatoma cell line Hepa-1c1c7 cells were treated with alpha-Hederin to assess the role of alpha-Hederin in the process of Cyp1a-1 induction. Treatment of Hepa-1c1c7 cultures with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced Cyp1a-1, as indicated by analysis of 7-ethoxyresorufin O-deethylation (EROD) activity and Cyp1a-1 protein. When alpha-Hederin and TCDD were both added to cultures, TCDD-inducible EROD activity was greatly suppressed by alpha-Hederin in a dose-dependent manner. TCDD-induced Cyp1a-1 protein and mRNA levels were markedly reduced in the concomitant treatment of TCDD and alpha-Hederin consistent with EROD activity. Electrophoretic mobility shift assay using nuclear extraction of cells revealed that alpha-Hederin reduced transformation of the Ah receptor to a form capable of specifically binding to an oligonucleotide containing a dioxin-response element (DRE) sequence of the Cyp1a-1 gene. These results suggest that the suppressive effect of alpha-Hederin on TCDD-induced Cyp1a-1 gene expression in Hepa-1c1c7 cells might be an antagonist of the DNA binding potential of a nuclear Ah receptor.

  9. Caffeic acid phenethyl ester inhibits 3-MC-induced CYP1A1 expression through induction of hypoxia-inducible factor-1α

    SciTech Connect

    Kim, Hyung Gyun; Han, Eun Hee; Im, Ji Hye; Lee, Eun Ji; Jin, Sun Woo; Jeong, Hye Gwang

    2015-09-25

    Caffeic acid phenethyl ester (CAPE), a natural component of propolis, is reported to have anticarcinogenic properties, although its precise chemopreventive mechanism remains unclear. In this study, we examined the effects of CAPE on 3-methylcholanthrene (3-MC)-induced CYP1A1 expression and activities. CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. Moreover, CAPE inhibited 3-MC-induced CYP1A1 activity, mRNA expression, protein level, and promoter activity. CAPE treatment also decreased 3-MC-inducible xenobiotic-response element (XRE)-linked luciferase, aryl hydrocarbons receptor (AhR) transactivation and nuclear localization. CAPE induced hypoxia inducible factor-1α (HIF-1α) protein level and HIF-1α responsible element (HRE) transcriptional activity. CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 protein expression. Taken together, CAPE decreases 3-MC-mediated CYP1A1 expression, and this inhibitory response is associated with inhibition of AhR and HIF-1α induction. - Highlights: • CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. • CAPE inhibited 3-MC-induced CYP1A1 expression. • CAPE induced HIF-1α induction. • CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 expression.

  10. Aryl hydrocarbon receptor protein and Cyp1A1 gene induction by LPS and phenanthrene in Atlantic cod (Gadus morhua) head kidney cells.

    PubMed

    Holen, Elisabeth; Olsvik, Pål Asgeir

    2014-10-01

    The objective of this study was to evaluate interactions between environmental toxicants and cod immune cells during inflammation. Phenanthrene is abundant in plant oils (rapeseed, palm, and soya oil) as compared to fish oils, and consequently constitute an undesirable element in plant replacement diets in aquaculture. Phenanthrene was added to head kidney cell cultures, alone or together with LPS (lipopolysaccharide) or poly I: C (polyinosinic acid: polycytidylic acid), and the responses were evaluated in terms of protein and gene expression. The results showed that LPS, poly I: C or phenanthrene, added to the cultures separately, induced aryl hydrocarbon receptor (AhR) protein expression. Phenanthrene treatment in combination with LPS induced AhR protein expression and Cyp1A1 gene transcription, which not was observed combining poly I: C and phenanthrene. Phenanthrene exposure up regulated the transcription of common stress and detoxification enzymes like catalase, caspase 3 and glutathione S-transferase alfa 3 subunit B (GSTAB3), while LPS exposure alone or combined with phenanthrene down regulated GSTAB3 and catalase in cod leukocytes. It seems clear that immune regulation and phenanthrene induced signaling pathways interact; transcriptional down regulation of detoxification and antioxidant enzymes by LPS could indicate that combating bacterial infections is the number one priority in these cells, and that AhR and Cyp1A1 is somehow involved in this signaling cascade. LPS seems to affect the mitogen activated protein kinases (MAPKs) pathways (P-p38 and ERK1/2) thus modulating the AhR protein and Cyp1A1 gene transcription, while phenanthrene possibly activates AhR by ligand binding.

  11. Protein expression of CYP1A1, CYP1B1, ALDH1A1, and ALDH2 in young patients with oral squamous cell carcinoma.

    PubMed

    Kaminagakura, E; Caris, A; Coutinho-Camillo, C; Soares, F A; Takahama-Júnior, A; Kowalski, L P

    2016-06-01

    The purpose of this study was to evaluate the expression of the enzymes involved in the biotransformation of tobacco and alcohol. A study group of 41 young patients (≤40 years old) with oral squamous cell carcinoma (OSCC) was compared to 59 control subjects (≥50 years old) with tumours of similar clinical stages and topographies. The immunohistochemical expression of CYP1A1, CYP1B1, ALDH1A1, and ALDH2 was evaluated using the tissue microarray technique. There was a predominance of males, smokers, and alcohol drinkers in both groups. Most tumours were located in the tongue (43.9% vs. 50.8%), were well-differentiated (63.4% vs. 56.6%), and were in clinical stages III or IV (80.5% vs. 78.0%). No difference was observed in the expression of CYP1A1, ALDH1A1, or ALDH2 between the two groups. CYP1A1 and ALDH2 protein expression had no influence on the prognosis. The immunoexpression of CYP1B1 was significantly higher in the control group than in the young group (P<0.001). The 5-year relapse-free survival was better in patients with CYP1B1 overexpression vs. protein underexpression (64% vs. 25%; P<0.05), regardless of age. ALDH1A1 expression improved relapse-free survival in young patients. These results suggest a lower risk of recurrence with increased metabolism of carcinogens by CYP1B1. Further studies involving other genes and proteins are necessary to complement the results of this research.

  12. Hypoxia perturbs aryl hydrocarbon receptor signaling and CYP1A1 expression induced by PCB 126 in human skin and liver-derived cell lines

    PubMed Central

    Vorrink, Sabine U.; Severson, Paul L.; Kulak, Mikhail V.; Futscher, Bernard W.; Domann, Frederick E.

    2014-01-01

    The aryl hydrocarbon receptor (AhR) is an important mediator of toxic responses after exposure to xenobiotics including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dioxin-like polychlorinated biphenyls (PCBs). Activation of AhR responsive genes requires AhR dimerization with the aryl hydrocarbon receptor nuclear translocator (ARNT), a heterodimeric partner also shared by the hypoxia-inducible factor-1α (HIF-1α) protein. TCDD-stimulated AhR transcriptional activity can be influenced by hypoxia; however, it less well known whether hypoxia interferes with AhR transcriptional transactivation in the context of PCB-mediated AhR activation in human cells. Elucidation of this interaction is important in liver hepatocytes which extensively metabolize ingested PCBs and experience varying degrees of oxygen tension during normal physiologic function. This study was designed to assess the effect of hypoxia on AhR transcriptional responses after exposure to 3,3',4,4',5-pentachlorobiphenyl (PCB 126). Exposure to 1% O2 prior to PCB 126 treatment significantly inhibited CYP1A1 mRNA and protein expression in human HepG2 and HaCaT cells. CYP1A1 transcriptional activation was significantly decreased upon PCB 126 stimulation under conditions of hypoxia. Additionally, hypoxia pre-treatment reduced PCB 126 induced AhR binding to CYP1 target gene promoters. Importantly, ARNT overexpression rescued cells from the inhibitory effect of hypoxia on XRE-luciferase reporter activity. Therefore, the mechanism of interference of the signaling crosstalk between the AhR and hypoxia pathways appears to be at least in part dependent on ARNT availability. Our results show that AhR activation and CYP1A1 expression induced by PCB 126 were significantly inhibited by hypoxia and hypoxia might therefore play an important role in PCB metabolism and toxicity. PMID:24355420

  13. Genetic polymorphisms in CYP1A1, CYP1B1 and COMT genes in Greenlandic Inuit and Europeans

    PubMed Central

    Ghisari, Mandana; Long, Manhai; Bonefeld-Jørgensen, Eva C.

    2013-01-01

    Background The Indigenous Arctic population is of Asian descent, and their genetic background is different from the Caucasian populations. Relatively little is known about the specific genetic polymorphisms in genes involved in the activation and detoxification mechanisms of environmental contaminants in Inuit and its relation to health risk. The Greenlandic Inuit are highly exposed to legacy persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), and an elucidation of gene–environment interactions in relation to health risks is needed. Objectives The aim of this study was to determine and compare the genotype and allele frequencies of the cytochrome P450 CYP1A1 Ile462Val (rs1048943), CYP1B1 Leu432Val (rs1056836) and catechol-O-methyltransferase COMT Val158Met (rs4680) in Greenlandic Inuit (n=254) and Europeans (n=262) and explore the possible relation between the genotypes and serum levels of POPs. Results The genotype and allele frequency distributions of the three genetic polymorphisms differed significantly between the Inuit and Europeans. For Inuit, the genotype distribution was more similar to those reported for Asian populations. We observed a significant difference in serum polychlorinated biphenyl (CB-153) and the pesticide 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p′-DDE) levels between Inuit and Europeans, and for Inuit also associations between the POP levels and genotypes for CYP1A1, CYP1B1 and COMT. Conclusion Our data provide new information on gene polymorphisms in Greenlandic Inuit that might support evaluation of susceptibility to environmental contaminants and warrant further studies. PMID:23785672

  14. Fluorinated 2-(4-amino-3-methylphenyl)benzothiazoles induce CYP1A1 expression, become metabolized, and bind to macromolecules in sensitive human cancer cells.

    PubMed

    Brantley, Eileen; Trapani, Valentina; Alley, Michael C; Hose, Curtis D; Bradshaw, Tracey D; Stevens, Malcolm F G; Sausville, Edward A; Stinson, Sherman F

    2004-12-01

    Fluorinated 2-(4-amino-3-methylphenyl)benzothiazoles possess potent antiproliferative activity against certain cancer cells, similar to the unfluorinated 2-(4-amino-3-methylphenyl)benzothiazole (DF 203, NSC 674495). In "sensitive" cancer cells, DF 203 is metabolized by, can induce expression of, and binds covalently to CYP1A1. Metabolism appears to be essential for its antiproliferative activity through DNA adduct formation. However, a biphasic dose-response relationship compromises its straightforward development as a chemotherapeutic agent. We investigated whether fluorinated benzothiazoles inhibit cancer cell growth without the biphasic dose-response, and whether the fluorinated benzothiazoles are also metabolized into reactive species, with binding to macromolecules in sensitive cancer cells. One fluorinated benzothiazole, 2-(4-amino-methylphenyl)-5-fluorobenzothiazole (5F 203, NSC 703786) did exhibit potent, antiproliferative activity without a biphasic dose-response. The fluorinated benzothiazoles were also metabolized only in cells, which subsequently showed evidence of cell death. We used microsomes from genetically engineered human B-lymphoblastoid cells expressing cytochromes P450 (CYP1A1, CYP1A2, or CYP1B1) to clarify the basis for fluorinated benzothiazole metabolism. 5F 203 induced CYP1A1 and CYP1B1 mRNA expression in sensitive breast and renal cancer cells, whereas 5F 203 induced CYP1A1 mRNA but not CYP1B1 mRNA expression in sensitive ovarian cancer cells. 5F 203 did not induce CYP1A1 or CYP1B1 mRNA expression in any "resistant" cancer cells. The fluorinated benzothiazoles induced CYP1A1 protein expression exclusively in sensitive cells. [14C]5F 203 bound substantially to subcellular fractions in sensitive cells but only minimally in resistant cells. These data are concordant with the antiproliferative activity of fluorinated benzothiazoles deriving from their ability to become metabolized and bind to macromolecules within sensitive cells.

  15. Pacific Ocean–Wide Profile of CYP1A1 Expression, Stable Carbon and Nitrogen Isotope Ratios, and Organic Contaminant Burden in Sperm Whale Skin Biopsies

    PubMed Central

    Godard-Codding, Céline A.J.; Clark, Rebecca; Fossi, Maria Cristina; Marsili, Letizia; Maltese, Silvia; West, Adam G.; Valenzuela, Luciano; Rowntree, Victoria; Polyak, Ildiko; Cannon, John C.; Pinkerton, Kim; Rubio-Cisneros, Nadia; Mesnick, Sarah L.; Cox, Stephen B.; Kerr, Iain; Payne, Roger; Stegeman, John J.

    2011-01-01

    Background Ocean pollution affects marine organisms and ecosystems as well as humans. The International Oceanographic Commission recommends ocean health monitoring programs to investigate the presence of marine contaminants and the health of threatened species and the use of multiple and early-warning biomarker approaches. Objective We explored the hypothesis that biomarker and contaminant analyses in skin biopsies of the threatened sperm whale (Physeter macrocephalus) could reveal geographical trends in exposure on an oceanwide scale. Methods We analyzed cytochrome P450 1A1 (CYP1A1) expression (by immunohistochemistry), stable nitrogen and carbon isotope ratios (as general indicators of trophic position and latitude, respectively), and contaminant burdens in skin biopsies to explore regional trends in the Pacific Ocean. Results Biomarker analyses revealed significant regional differences within the Pacific Ocean. CYP1A1 expression was highest in whales from the Galapagos, a United Nations Educational, Scientific, and Cultural Organization World Heritage marine reserve, and was lowest in the sampling sites farthest away from continents. We examined the possible influence of the whales’ sex, diet, or range and other parameters on regional variation in CYP1A1 expression, but data were inconclusive. In general, CYP1A1 expression was not significantly correlated with contaminant burdens in blubber. However, small sample sizes precluded detailed chemical analyses, and power to detect significant associations was limited. Conclusions Our large-scale monitoring study was successful at identifying regional differences in CYP1A1 expression, providing a baseline for this known biomarker of exposure to aryl hydrocarbon receptor agonists. However, we could not identify factors that explained this variation. Future oceanwide CYP1A1 expression profiles in cetacean skin biopsies are warranted and could reveal whether globally distributed chemicals occur at biochemically

  16. Genetic polymorphisms of CYP1A1, GSTM1 and P53 genes in a unique Siberian population of Tundra Nentsi and its pharmacogenetic importance.

    PubMed

    Duzhak, T G; Osipova, L P; Posukh, O L; Chasovnikova, O B; Ostashevskii, V I; Lyakhovich, V V

    2001-04-01

    Complete data on the polymorphisms of CYP1A1, GSTM1 and p53 genes in Tundra Nentsi population, with known genealogical history are essential for the analysis of the "cancer susceptibility gene markers" distribution among different Oriental populations. The cytochrome P4501A subfamily is known to be responsible for the metabolic activation of aromatic compounds occurring in the products of gas mixture combustion, the main environmental pollutants in the north of western Siberia. Recently a close correlation was reported between development of some types of cancer and polymorphisms of human CYP1A1, GSTM1 and p53 genes. The frequency of the CYP1A1 Vol allele in the healthy part of the Tundra Nentsi population differs from those previously reported for Japanese and is more than 1.5 times higher. It is necessary to underline that homozygote Val genotype was present in 26% of non-healthy Tundra Nentsi, the incidence being 2.7-times higher in comparison with healthy population. GSTM1 gene deletion is present in 40% of Orientals and in 39% of Tundra Nentsi. Moreover, the share of individuals with null genotype among a group with chromosomal abnormalities and cancer was 63%, or 1.5 fold higher. Thus the prevalence of two polymorphic genes CYP1A1 and GSTM1 responsible for the biotransformation of polycyclic aromatic hydrocarbons was too high in the non-healthy group.

  17. Cellular glutathione content modulates the effect of andrographolide on β-naphthoflavone-induced CYP1A1 mRNA expression in mouse hepatocytes.

    PubMed

    Kondo, Sachiko; Chatuphonprasert, Waranya; Jaruchotikamol, Atika; Sakuma, Tsutomu; Nemoto, Nobuo

    2011-02-04

    We previously reported that andrographolide (Andro), a major bioactive constituent of Andrographis paniculata, synergistically enhanced the inducible expression of CYP1A1 mRNA. In this study, although the synergism was confirmed at 24h after the start of treatment with Andro and β-naphthoflavone (βNF), a CYP1A inducer, the expression was profoundly suppressed at an earlier phase, namely at 6-12h, when the βNF-induced expression peaked. Although oxidized glutathione (GSSG) levels were higher in co-treated cells at 6 and 24h, levels of reactive oxygen species varied depending on the treatment period and species, indicating no relation to the synergistic expression of CYP1A1 mRNA. Glutathione (GSH) and N-acetyl-l-cysteine (NAC) significantly enhanced the βNF-induced expression, and partly reversed the suppressive effect of Andro in the early phase. At 24h, the addition of GSH or NAC had no effect on βNF-induced CYP1A1 mRNA expression, but significantly reduced the synergistic effect of Andro. The synergistic effect was enhanced by l-buthionine-(S,R)-sulfoximine, a GSH depleter. Furthermore, H(2)O(2) and ascorbic acid further modified the profile of synergism of Andro on βNF-inducible CYP1A1 mRNA expression. These results suggest that GSH status might be involved in βNF-induced CYP1A1 mRNA expression, and the interaction of Andro with GSH might modulate the expression.

  18. Caffeic acid phenethyl ester inhibits 3-MC-induced CYP1A1 expression through induction of hypoxia-inducible factor-1α.

    PubMed

    Kim, Hyung Gyun; Han, Eun Hee; Im, Ji Hye; Lee, Eun Ji; Jin, Sun Woo; Jeong, Hye Gwang

    2015-09-25

    Caffeic acid phenethyl ester (CAPE), a natural component of propolis, is reported to have anticarcinogenic properties, although its precise chemopreventive mechanism remains unclear. In this study, we examined the effects of CAPE on 3-methylcholanthrene (3-MC)-induced CYP1A1 expression and activities. CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. Moreover, CAPE inhibited 3-MC-induced CYP1A1 activity, mRNA expression, protein level, and promoter activity. CAPE treatment also decreased 3-MC-inducible xenobiotic-response element (XRE)-linked luciferase, aryl hydrocarbons receptor (AhR) transactivation and nuclear localization. CAPE induced hypoxia inducible factor-1α (HIF-1α) protein level and HIF-1α responsible element (HRE) transcriptional activity. CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 protein expression. Taken together, CAPE decreases 3-MC-mediated CYP1A1 expression, and this inhibitory response is associated with inhibition of AhR and HIF-1α induction.

  19. All-trans retinoic acid inhibits the recruitment of ARNT to DNA, resulting in the decrease of CYP1A1 mRNA expression in HepG2 cells

    SciTech Connect

    Ohno, Marumi; Ikenaka, Yoshinori; Ishizuka, Mayumi

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer AHR and ARNT transcriptionally regulate genes related to metabolisms such as CYP1A1. Black-Right-Pointing-Pointer We investigated the effect of retinoic acid (RA) on the function of AHR/ARNT. Black-Right-Pointing-Pointer RA inhibited the recruitment of ARNT, not AHR, to the regulatory region of CYP1A1. Black-Right-Pointing-Pointer It resulted in a reduction of constitutive expression of CYP1A1 to less than half. -- Abstract: Aryl hydrocarbon receptor (AHR) and AHR nuclear translocator (ARNT) are well-conserved transcription factors among species. However, there are a very limited number of reports on the physiological function of AHR, particularly on the regulation of AHR by endogenous compounds. We hence investigated the effects of all-trans retinoic acid (atRA) on cytochrome P450 (CYP) 1A1 gene transcription as a model of AHR-regulated transcription mechanisms in HepG2 cells, a human hepatoma cell line. Treatment with atRA significantly reduced transactivation and expression of CYP1A1 mRNA to less than half of its control value, and this inhibitory effect was mediated by RAR{alpha}. The result of chromatin immunoprecipitation assay indicated that treatment with atRA at 1-100 nM drastically inhibited the recruitment of ARNT to DNA regions containing xenobiotic responsive elements. In conclusion, atRA at physiological concentrations could reduce AHR-mediated gene transcription via the inhibition of recruitment of ARNT to relevant DNA regions.

  20. Ah receptor, CYP1A1, CYP1A2 and CYP1B1 gene polymorphisms are not involved in the risk of recurrent pregnancy loss.

    PubMed

    Saijo, Y; Sata, F; Yamada, H; Suzuki, K; Sasaki, S; Kondo, T; Gong, Y Y; Kato, E H; Shimada, S; Morikawa, M; Minakami, H; Kishi, R

    2004-10-01

    The etiology of recurrent pregnancy loss (RPL) remains unclear, but it may be related to a possible genetic predisposition together with involvement of environmental factors. We examined the relation between RPL and polymorphisms in four genes, human aryl hydrocarbon (Ah) receptor, cytochrome P450 (CYP) 1A1, CYP1A2 and CYP1B1, which are involved in the metabolism of a wide range of environmental toxins and carcinogens. All cases and controls were women resident in Sapporo, Japan and the surrounding area. The Ah receptor, CYP1A1, CYP1A2 and CYP1B1 genotypes were assessed in 113 Japanese women with recurrent pregnancy loss (RPL) and 203 ethnically matched women experiencing at least one live birth and no spontaneous abortion (control). No significant differences in Ah receptor, CYP1A1, CYP1A2 and CYP1B1 genotype frequencies were found between the women with RPL and the controls [Ah receptor: Arg/Arg (reference); Arg/Lys and Lys/Lys, odds ratio (OR)=0.67; 95% confidence interval (CI)=0.40-1.11, CYP1A1: m1m1 (reference); m1m2 and m2m2, OR = 0.86; 95% CI = 0.53-1.40, CYP1A2: C/C and C/A (reference); A/A, OR = 1.16; 95% CI = 0.71-1.88, CYP1B1: Leu/Leu (reference); Leu/Val and Val/Val, OR = 1.18; 95% CI = 0.68-2.02]. The present study suggests that the Ah receptor, CYP1A1, CYP1A2 and CYP1B1 gene polymorphisms are not major genetic regulators in RPL.

  1. Genetic variation in the CYP1A1 gene is related to circulating PCB118 levels in a population-based sample

    SciTech Connect

    Lind, Lars; Penell, Johanna; Syvänen, Anne-Christine; Axelsson, Tomas; Ingelsson, Erik; Morris, Andrew P.; Lindgren, Cecilia; Salihovic, Samira; Bavel, Bert van; Lind, P. Monica

    2014-08-15

    Several of the polychlorinated biphenyls (PCBs), i.e. the dioxin-like PCBs, are known to induce the P450 enzymes CYP1A1, CYP1A2 and CYP1B1 by activating the aryl hydrocarbon receptor (Ah)-receptor. We evaluated if circulating levels of PCBs in a population sample were related to genetic variation in the genes encoding these CYPs. In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (1016 subjects all aged 70), 21 SNPs in the CYP1A1, CYP1A2 and CYP1B1 genes were genotyped. Sixteen PCB congeners were analysed by high-resolution chromatography coupled to high-resolution mass spectrometry (HRGC/ HRMS). Of the investigated relationships between SNPs in the CYP1A1, CYP1A2 and CYP1B1 and six PCBs (congeners 118, 126, 156, 169, 170 and 206) that captures >80% of the variation of all PCBs measured, only the relationship between CYP1A1 rs2470893 was significantly related to PCB118 levels following strict adjustment for multiple testing (p=0.00011). However, there were several additional SNPs in the CYP1A2 and CYP1B1 that showed nominally significant associations with PCB118 levels (p-values in the 0.003–0.05 range). Further, several SNPs in the CYP1B1 gene were related to both PCB156 and PCB206 with p-values in the 0.005–0.05 range. Very few associations with p<0.05 were seen for PCB126, PCB169 or PCB170. Genetic variation in the CYP1A1 was related to circulating PCB118 levels in the general elderly population. Genetic variation in CYP1A2 and CYP1B1 might also be associated with other PCBs. - Highlights: • We studied the relationship between PCBs and the genetic variation in the CYP genes. • Cross sectional data from a cohort of elderly were analysed. • The PCB levels were evaluated versus 21 SNPs in three CYP genes. • PCB 118 was related to variation in the CYP1A1 gene.

  2. Sequencing and characterization of mixed function monooxygenase genes CYP1A1 and CYP1A2 of Mink (Mustela vison) to facilitate study of dioxin-like compounds

    SciTech Connect

    Zhang Xiaowei; Moore, Jeremy N.; Newsted, John L.; Hecker, Markus Zwiernik, Matthew J.; Jones, Paul D.; Bursian, Steven J.

    2009-02-01

    As part of an ongoing effort to understand aryl hydrocarbon receptor (AhR) mediated toxicity in mink, cDNAs encoding for CYP1A1 and the CYP1A2 mixed function monooxygenases were cloned and characterized. In addition, the effects of selected dibenzofurans on the expression of these genes and the presence of their respective proteins (P4501A) were investigated, and then correlated with the catalytic activities of these proteins as measured by ethoxyresorufin O-deethylase (EROD) and methoxyresorufin O-deethylase (MROD) activities. The predicted protein sequences for CYP1A1 and CYP1A2 comprise 517 and 512 amino acid residues, respectively. The phylogenetic analysis of the mink CYP1As with protein sequences of other mammals revealed high sequence homology with sea otter, seals and the dog, with amino acid identities ranging from 89 to 95% for CYP1A1 and 81 to 93% for CYP1A2. Since exposure to both 2,3,7,8-Tetrachlorodibenzofuran (TCDF) and 2,3,4,7,8-Pentachlorodibenzofuran (PeCDF) resulted in dose-dependent increases of CYP1A1 mRNA, CYP1A2 mRNA and CYP1A protein levels an underlying AhR-mediated mechanism is suggested. The up-regulation of CYP1A mRNA in liver was more consistent to the sum adipose TEQ concentration than to the liver TEQ concentration in minks treated with TCDF or PeCDF. The result suggested that the hepatic-sequestered fraction of PeCDF was biologically inactive to the induction of CYP1A1 and CYP1A2.

  3. Triclosan activates aryl hydrocarbon receptor (AhR)-dependent apoptosis and affects Cyp1a1 and Cyp1b1 expression in mouse neocortical neurons.

    PubMed

    Szychowski, Konrad A; Wnuk, Agnieszka; Kajta, Małgorzata; Wójtowicz, Anna K

    2016-11-01

    Triclosan (TCS) is an antimicrobial agent that is used extensively in personal care and in sanitizing products, such as soaps, toothpastes, and hair products. A number of studies have revealed the presence of TCS in human tissues, such as fat, liver and brain, in addition to blood and breast milk. The aim of the present study was to investigate the impact of TCS on AhR and Cyp1a1/Cyp1b1 signaling in mouse neocortical neurons in primary cultures. In addition to the use of selective ligands and siRNAs, expression levels of mRNA and proteins as well as caspase-3 activity, reactive oxygen species (ROS) formation, and lactate dehydrogenase (LDH) release have been measured. We also studied the involvement of the AhR in TCS-induced LDH release and caspase-3 activation as well as the effect of TCS on ROS generation. Cultures of neocortical neurons were prepared from Swiss mouse embryos on day 15/16 of gestation. The cells were cultured in phenol red-free Neurobasal medium with B27 and glutamine, and the neurons were exposed to 1 and 10µM TCS. Our experiments showed that the expression of AhR and Cyp1a1 mRNA decreased in cells exposed to 10µM TCS for 3 or 6h. In the case of Cyp1b1, mRNA expression remained unchanged compared with the control group following 3h of exposure to TCS, but after 6h, the mRNA expression of Cyp1b1 was decreased. Our results confirmed that the AhR is involved in the TCS mechanism of action, and our data demonstrated that after the cells were transfected with AhR siRNA, the cytotoxic and pro-apoptotic properties of TCS were decreased. The decrease in Cyp1a1 mRNA and protein expression levels accompanied by a decrease in its activity. The stimulation of Cyp1a1 activity produced by the application of an AhR agonist (βNF) was attenuated by TCS, whereas the addition of AhR antagonist (αNF) reversed the inhibitory effects of TCS. In our experiments, TCS diminished Cyp1b1 mRNA and enhanced its protein expression. In case of Cyp1a1 we observed

  4. Polymorphisms in the cytochrome P-450 (CYP) 1A1 and 17 genes are not associated with acne vulgaris in the Polish population

    PubMed Central

    Zabłotna, Monika; Dobosz-Kawałko, Magdalena; Michajłowski, Igor; Mędrzycka-Dąbrowska, Wioletta; Nowicki, Roman; Sokołowska-Wojdyło, Małgorzata

    2015-01-01

    Introduction The pathogenesis of acne is complex, multifactorial and not well understood. The genetic background of this dermatosis is well documented. Aim To assess the frequency of –34 T > C single nucleotide polymorphism in the promoter of the CYP17 gene as well as m1 (+6,235 T > C) and m2 (+4,889 A > G) mutation in the coding region CYP1A1 gene acne patients from the Northern Polish population. Material and methods The study included 115 acne patients and 94 healthy controls (aged over 20) without acne in anamnesis. The CYP1A1 polymorphism was analyzed by polymerase chain reaction (PCR). The restriction fragment length polymorphism (RFLP) was used to analyze m1 mutation and allele-specific PCR in the case of m2 mutation. The CYP17 polymorphism was analyzed by RFLP. The results were evaluated by the Pearson's χ2 test. Results There were no statistically significant associations between allele and genotype frequencies between the acne and the control group. Conclusions We did not confirm the role of the CYP1A1 and CYP17 gene as predictor factors for acne development in the Polish population. PMID:26759538

  5. Genome Editing of the CYP1A1 Locus in iPSCs as a Platform to Map AHR Expression throughout Human Development

    PubMed Central

    Smith, Brenden W.; Stanford, Elizabeth A.; Sherr, David H.; Murphy, George J.

    2016-01-01

    The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that increases the expression of detoxifying enzymes upon ligand stimulation. Recent studies now suggest that novel endogenous roles of the AHR exist throughout development. In an effort to create an optimized model system for the study of AHR signaling in several cellular lineages, we have employed a CRISPR/CAS9 genome editing strategy in induced pluripotent stem cells (iPSCs) to incorporate a reporter cassette at the transcription start site of one of its canonical targets, cytochrome P450 1A1 (CYP1A1). This cell line faithfully reports on CYP1A1 expression, with luciferase levels as its functional readout, when treated with an endogenous AHR ligand (FICZ) at escalating doses. iPSC-derived fibroblast-like cells respond to acute exposure to environmental and endogenous AHR ligands, and iPSC-derived hepatocytes increase CYP1A1 in a similar manner to primary hepatocytes. This cell line is an important innovation that can be used to map AHR activity in discrete cellular subsets throughout developmental ontogeny. As further endogenous ligands are proposed, this line can be used to screen for safety and efficacy and can report on the ability of small molecules to regulate critical cellular processes by modulating the activity of the AHR. PMID:27148368

  6. Phytoremediation of the herbicides atrazine and metolachlor by transgenic rice plants expressing human CYP1A1, CYP2B6, and CYP2C19.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2006-04-19

    This study evaluated the expression of human cytochrome P450 genes CYP1A1, CYP2B6, and CYP2C19 in rice plants (Oryza sativa cv. Nipponbare) introduced using the plasmid pIKBACH. The transgenic rice plants (pIKBACH rice plants) became more tolerant toward various herbicides than nontransgenic Nipponbare rice plants. Rice plants expressing pIKBACH grown in soil showed tolerance to the herbicides atrazine, metolachlor, and norflurazon and to a mixture of the three herbicides. The degradation of atrazine and metolachlor by pIKBACH rice plants was evaluated to confirm the metabolic activity of the introduced P450s. Although both pIKBACH and nontransgenic Nipponbare rice plants could decrease the amounts of the herbicides in plant tissue and culture medium, pIKBACH rice plants removed greater amounts in greenhouse experiments. The ability of pIKBACH rice plants to remove atrazine and metolachlor from soil was confirmed in large-scale experiments. The metabolism of herbicides by pIKBACH rice plants was enhanced by the introduced P450 species. Assuming that public and commercial acceptance is forthcoming, pIKBACH rice plants may become useful tools for the breeding of herbicide-tolerant crops and for phytoremediation of environmental pollution by organic chemicals.

  7. CYP1A1 genetic polymorphism and polycyclic aromatic hydrocarbons on pulmonary function in the elderly: haplotype-based approach for gene-environment interaction.

    PubMed

    Choi, Yoon-Hyeong; Kim, Jin Hee; Hong, Yun-Chul

    2013-08-29

    Lung function may be impaired by environmental pollutants not only acting alone, but working with genetic factors as well. Few epidemiologic studies have been conducted to explore the interplay of polycyclic aromatic hydrocarbons (PAHs) exposure and genetic polymorphism on lung function in the elderly. For genetic polymorphism, haplotype is considered a more informative unit than single nucleotide polymorphism markers. Therefore, we examined the role of haplotype based-CYP1A1 polymorphism in the effect of PAHs exposure on lung function in 422 participants from a community-based panel of elderly adults in Seoul, Korea. Linear mixed effect models were fit to evaluate the association of PAH exposure markers (urinary 1-hydroxypyrene and 2-naphthol) with FVC, FEV₁, FEV₁/FVC, and FEF₂₅₋₇₅, and then the interaction with CYP1A1 haplotype constructed from three single nucleotide polymorphisms of the gene (rs4646421/rs4646422/rs1048943). Urinary 1-hydroxypyrene levels were inversely associated with FEV₁/FVC (p<0.05), whereas urinary 2-naphthol levels failed to show associations with lung function. Urinary 1-hydroxypyrene was significantly associated with decrease in FEV₁/FVC among participants with rs4646421 variants (CT+TT), rs4646422 wild-type (GG), and rs1048943 wild-type (AA). At least one TGA haplotype predicted a 0.88% (95% confidence interval, 0.31-1.45%) reduction in FEV₁/FVC with an interquartile range increase in 1-hydroxypyrene, whereas no relationship was observed in participants without TGA haplotype (p for interaction=0.045). Similar patterns were also observed in FEF₂₅₋₇₅. We did not find any main effects of CYP1A1 genetic polymorphisms on lung functions. Our findings suggest that PAH exposure producing 1-hydroxypyrene as a metabolite compromises lung function in the elderly, and that haplotype-based CYP1A1 polymorphism modifies the risk.

  8. Estrogen Receptor α Increases Basal and Cigarette Smoke Extract-Induced Expression of CYP1A1 and CYP1B1, but not GSTP1, in Normal Human Bronchial Epithelial Cells

    PubMed Central

    Han, W; Pentecost, BT; Pietropaolo, RL; Fasco, MJ; Spivack, SD

    2005-01-01

    Gender-specific estrogen receptor α (ERα) expression may plausibly influence lung carcinogenesis in females. Initial genome-wide microarray studies confirmed that carcinogen metabolism genes (CYP1A1, CYP1B1) were those most responsive to cigarette smoke extract (CSE) in normal bronchial epithelial (NHBE) cells. These two genes encoding phase I bioactivating enzymes and the GSTP1 gene encoding a phase II deactivating enzyme were then tested for induction by ERα. NHBE cells (native ERα−) were transfected with wild-type ERα-adenoviral constructs, and then exposed to CSE, 17β-estradiol (E2), and/or the ERα inhibitor, ICI 182,780. The expression levels of CYP1A1, CYP1B1 and GSTP1 were then determined by RNA-specific quantitative RT-PCR and immunoassay. ERα increased the basal expression of CYP1B1 4.04-fold (p<0.01) at the mRNA level and 6.5-fold at the protein level. ERα also increased the CSE-induced mRNA expression of CYP1B1 2.26-fold (p<0.01), but not the protein expression. ERα did not alter the CYP1A1 mRNA levels, but did increase protein expression 2.0-fold (p<0.01) on CSE exposure, and 6.2-fold (p<0.01) upon E2 exposure. These effects could be inhibited by ICI 182,780. ERα did not alter the expression of GSTP1. ChIP assay confirmed ERα binding to CYP1B1 promoter near the transcription start site. These results suggest that ERα regulates the CYP1B1 expression at a transcriptional level, and CYP1A1 expression at a translational level. These data raise the possibility that inter-gender differences in expression of ERα that are known to exist in human lung may contribute to inter-individual expression differences in CYP1A1 and CYP1B1, and to differences in carcinogen metabolism and mutation. PMID:16010691

  9. Genetic polymorphisms of CYP2D6, CYP1A1, GSTM1 and p53 genes in a unique Siberian population of Tundra Nentsi.

    PubMed

    Duzhak, T; Mitrofanov, D; Ostashevskii, V; Gutkina, N; Chasovnikova, O; Posukh, O; Osipova, L; Lyakhovich, V V

    2000-08-01

    GSTM1*0/*0 genotypes and a high level of CYP1A1Val alleles. Further investigations of gene polymorphisms in isolated Northern native populations would be valuable in clarifying the origin of Northern natives. All this is important for comparative analyses of pharmacogenetic data in Mongoloid populations.

  10. CYP1A1 and CYP1B1 expressions in medulloblastoma cells are AhR-independent and have no direct link with resveratrol-induced differentiation and apoptosis.

    PubMed

    Wu, Mo-Li; Li, Hong; Wu, Da-Chang; Wang, Xiao-Wei; Chen, Xiao-Yan; Kong, Qing-You; Ma, Jing-Xin; Gao, Ying; Liu, Jia

    Resveratrol induces apoptosis and regulates CYP1A1 and CYP1B1 expression in human medulloblastoma cells. To elucidate the potential correlation of their expressions with the anti-medulloblastoma effects of resveratrol, human medulloblastoma cells, UW228-3, were treated with CYP1A1 selective inhibitor (alpha-naphthoflavone, alpha-NF), selective CYP1A1/1A2 inducer (beta-naphthoflavone, beta-NF) and their combination with resveratrol, respectively. The influences of those treatments on the expressions of CYP1A1, 1A2 and 1B1 as well as the cell growth, differentiation and death were analyzed. It was found that neither alpha-NF nor beta-NF had any effect on cell growth. alpha-NF inhibited resveratrol-induced CYP1A1 expression without interfering cell differentiation and apoptosis. beta-NF could up-regulate resveratrol-induced CYP1A1 expression but not enhance the anti-cancer effects of resveratrol. CYP1A2 was undetectable in the cells irrespective to the treatments. Aryl hydrocarbon receptor (AhR) was absent in UW228-3 cells under normal culture and treated with resveratrol but induced by both alpha- and beta-NF. Immunohistochemical examination performed on 11 pairs of human medulloblastoma and noncancerous cerebellar tissues revealed that AhR was undetectable in either of them, whereas CYP1A1 was expressed in cerebellum but down-regulated or diminished in their malignant counterparts. Our data suggest for the first time that CYP1A1 and 1B1 expressions in human medulloblastoma cells are AhR-independent and have no direct links with resveratrol-induced differentiation and apoptosis. Appearance of CYP1A1 expression may reflect a more maturated status and a better prognosis of medulloblastomas.

  11. Association of CYP1A1, CYP1B1 and CYP17 gene polymorphisms and organochlorine pesticides with benign prostatic hyperplasia.

    PubMed

    Kumar, Vivek; Banerjee, Basu Dev; Datta, Sudip Kumar; Yadav, Chandra Shekhar; Singh, Satyender; Ahmed, Rafat Sultana; Gupta, Sanjay

    2014-08-01

    It is well established that steroidal hormones (testosterone and estrogen) increase benign prostatic hyperplasia (BPH) risk. Cytochrome P450 (CYP) enzymes especially CYP1A1, CYP1B1 and CYP17 metabolize these hormones. Apart from that, several endocrine disrupting organochlorine pesticides (OCPs) are reported to mimic the activity of these steroidal hormones. Therefore, functional polymorphisms in these genes and exposure to such pesticides may increase BPH risk further. Our study included 100 newly diagnosed BPH subjects and 100 age-matched healthy male controls. CYP1A1, CYP1B1 and CYP17 polymorphisms were studied using PCR-RFLP and allele-specific PCR method. OCP levels in blood were analyzed by gas chromatography (GC). Levels of p,p'-DDE and endosulfan α were found to be significantly higher amongst BPH subjects as compared to controls (p-values=0.001 and 0.03 respectively) and CYP17 polymorphism was observed to be significantly associated with BPH subjects as compared to controls (p-values=0.03), indicating that these factors may be important risk factors for BPH. However, further studies are required before unequivocal conclusion.

  12. Harman induces CYP1A1 enzyme through an aryl hydrocarbon receptor mechanism

    SciTech Connect

    El Gendy, Mohamed A.M.; El-Kadi, Ayman O.S.

    2010-11-15

    Harman is a common compound in several foods, plants and beverages. Numerous studies have demonstrated its mutagenic, co-mutagenic and carcinogenic effects; however, the exact mechanism has not been fully identified. Aryl hydrocarbon receptor (AhR) is a transcription factor regulating the expression of the carcinogen-activating enzyme; cytochrome P450 1A1 (CYP1A1). In the present study, we examined the ability of harman to induce AhR-mediated signal transduction in human and rat hepatoma cells; HepG2 and H4IIE cells. Our results showed that harman significantly induced CYP1A1 mRNA in a time- and concentration-dependent manner. Similarly, harman significantly induced CYP1A1 at protein and activity levels in a concentration-dependent manner. Moreover, the AhR antagonist, resveratrol, inhibited the increase in CYP1A1 activity by harman. The RNA polymerase inhibitor, actinomycin D, completely abolished the CYP1A1 mRNA induction by harman, indicating a transcriptional activation. The role of AhR in CYP1A1 induction by harman was confirmed by using siRNA specific for human AhR. The ability of harman to induce CYP1A1 was strongly correlated with its ability to stimulate AhR-dependent luciferase activity and electrophoretic mobility shift assay. At post-transcriptional and post-translational levels, harman did not affect the stability of CYP1A1 at the mRNA and the protein levels, excluding other mechanisms participating in the obtained effects. We concluded that harman can directly induce CYP1A1 gene expression in an AhR-dependent manner and may represent a novel mechanism by which harman promotes mutagenicity, co-mutagenicity and carcinogenicity.

  13. Enzymatic characterization of in vitro-expressed Baikal seal cytochrome P450 (CYP) 1A1, 1A2, and 1B1: implication of low metabolic potential of CYP1A2 uniquely evolved in aquatic mammals.

    PubMed

    Iwata, Hisato; Yamaguchi, Keisuke; Takeshita, Yoko; Kubota, Akira; Hirakawa, Shusaku; Isobe, Tomohiko; Hirano, Masashi; Kim, Eun-Young

    2015-05-01

    This study aimed to elucidate the catalytic function of cytochrome P450 (CYP) 1 enzymes in aquatic mammals. Alkoxyresorufin O-dealkylation (AROD) activities including methoxy- (MROD), ethoxy- (EROD), pentoxy- (PROD), and benzyloxyresorufin O-dealkylation (BROD), and 2- and 4-hydroxylation activities of 17β-estradiol (E2) were measured by using yeast-expressed Baikal seal (Pusa sibirica) CYP1A1, 1A2, and 1B1 proteins. Heterologous protein expression of the Baikal seal CYP1s (bsCYP1s) in yeast microsomes was confirmed by reduced CO-difference spectra and immunoblotting. Heterologously expressed human CYP1 enzyme (hCYP1) activities were simultaneously measured and compared with those of bsCYP1 isozymes. Recombinant bsCYP1A1 protein showed the highest Vmax of EROD, followed by MROD, PROD, and BROD, similar to that of hCYP1A1. Vmax/Km ratios of all AROD activities catalyzed by bsCYP1A1 were lower than those catalyzed by hCYP1A1, suggesting less potential for AROD by bsCYP1A1. Enzymatic assays for bsCYP1A2 showed no or minimal AROD activities, while hCYP1A2 displayed MROD and EROD activities. bsCYP1B1 showed an AROD profile (EROD>BROD>MROD>PROD) similar to that of hCYP1B1; however, Vmax/Km ratios of all AROD activities by bsCYP1B1 were higher. Yeast microsomes containing bsCYP1A1 and 1B1 and hCYP1A1, 1A2, and 1B1 metabolized E2 to 2-OHE2 and 4-OHE2, whereas bsCYP1A2 showed no such activity. Comparison of 4- and 2-hydroxylations of E2 by CYP1As suggests that bsCYP1A1, hCYP1A1, and 1A2 preferentially catalyze 2- rather than 4-hydroxylation. As for CYP1B1, the Vmax/Km ratios suggest that both Baikal seal and human CYPs catalyze 4- rather than 2-hydroxylation. Interspecies comparison showed that bsCYP1B1 has higher metabolic potencies for both E2 hydroxylations than does hCYP1B1, whereas the activity of bsCYP1A1 was lower than that of hCYP1A1. Messenger RNA expression levels of bsCYP1s in the liver of Baikal seals indicated that bsCYP1A1 and 1A2 enzymes contributed to 16

  14. Intracellular accumulation of mercury enhances P450 CYP1A1 expression and Cl- currents in cultured shark rectal gland cells.

    PubMed

    Ke, Qingen; Yang, Yinke; Ratner, Martha; Zeind, John; Jiang, Canwen; Forrest, John N; Xiao, Yong-Fu

    2002-04-21

    The effects of acute and subchronic exposure to mercury on the Cl- current (ICl) were investigated in cultured shark rectal gland (SRG) cells. The effects of intracellular accumulation of mercury on cytochrome P450 (P450) were also assessed. Bath perfusion of a cocktail solution containing forskolin, 1-isobutyl-3-methylxanthine, and 8-bromoadenosine monophosphate enhanced ICl. Addition of 10 microM HgCl2 significantly inhibited the cAMP-activated ICl (p < 0.05, n = 11). Intracellular dialysis with ATP gamma S did not prevent the inhibitory effect of mercury on ICl. In contrast, incubation of SRG cells with 10 microM HgCl2 for 48 hrs markedly increased ICl (p < 0.01, n = 12). Dephosphorylation of the channel by intracellular dialysis with phosphatase I and II abolished the mercury-incubated increase in ICl. The P450-mediated metabolite of arachidonic acid, 11,12-epoxyeicosatrienoic acid (11,12-EET), significantly increased ICl. However, application of 11,12-dihydroxyeicosatrienoic acid (11,12-DHT) did not alter ICl. Mercury incubation for 48 hrs did not alter the protein expression of Cl- channels, but caused an induction of CYP1A1 in cultured SRG cells. In addition, co-incubation of SRG cells with mercury and the P450 inhibitor clotrimazole prevented the mercury-incubated increase in ICl. Our results demonstrate that acute and subchronic application of mercury has opposing effects on ICl in cultured SRG cells. The acute effect of mercury on ICl may result from mercury blockade of Cl- channels. The subchronic effect of mercury on ICl may be due to an induction of P450 CYP1A1 and its mediated metabolites, but not due to an over-expression of Cl- channels.

  15. An evaluation of the etiology of reduced CYP1A1 messenger RNA expression in the Atlantic tomcod from the Hudson River, New York, USA, using reverse transcriptase polymerase chain reaction analysis.

    PubMed

    Roy, N K; Courtenay, S; Yuan, Z; Ikonomou, M; Wirgin, I

    2001-05-01

    Adult Atlantic tomcod, Microgadus tomcod, from the Hudson River, New York State, USA, exhibit reduced inducibility of hepatic cytochrome P4501A1 (CYP1A1) mRNA compared with adult tomcod from the cleaner Miramichi River, New Brunswick, Canada, when treated with coplanar polychlorinated biphenyl (PCB) congeners or 2,3,7,8-tetrachlorodibenzo-p-dioxin. In contrast, little difference in CYP1A1 inducibility is observed between tomcod from these two rivers when treated with polycyclic aromatic hydrocarbons (PAHs). We sought to determine if impaired hepatic CYP1A1 inducibility in Hudson River tomcod results from a multigenerational, genetic adaptation or a single generational, physiological acclimation. Embryos and larvae from controlled experimental crosses of Hudson River and Miramichi River parents were exposed for 24 h to water-borne PCB congener 77 (10 ppm), benzo[a]pyrene (BaP; 10 ppm), or dimethysulfoxide, and CYP1A1 expression was assessed in individual larva using competitive reverse transcriptase polymerase chain reaction (RT-PCR) analysis. The CYP1A1 mRNA was significantly induced in larvae from both populations by BaP (47- and 52-fold) and PCB 77 (9- and 22-fold), although levels of expression were higher in offspring of Miramichi matings. Most important, CYP1A1 mRNA was significantly induced by PCB 77 in larvae from Hudson River parents. Concentrations of dioxin, furan, and PCB congeners were measured in livers and eggs of female tomcod from these two locales to quantify the extent of maternal transfer of contaminants. For both rivers, wet-weight contaminant concentrations were significantly higher (4-7 times) in livers than in eggs of the same females, suggesting that a threshold level of contaminants may have to be reached before CYP1A1 transcription is impaired. We conclude that reduced inducibility of hepatic CYP1A1 mRNA in adult tomcod from the Hudson River is most consistent with single-generational acclimation.

  16. Colorectal cancer and genetic polymorphisms of CYP1A1, GSTM1 and GSTT1: a case-control study in the Grampian region of Scotland.

    PubMed

    Little, Julian; Sharp, Linda; Masson, Lindsey F; Brockton, Nigel T; Cotton, Seonaidh C; Haites, Neva E; Cassidy, Jim

    2006-11-01

    Cytochrome P-450 CYP1A1 is involved in the metabolism of polycyclic aromatic hydrocarbons (PAHs) that are derived from meat intake and tobacco smoking. Expression of the CYP1A1 gene is induced by compounds present in cruciferous vegetables. The glutathione S-transferases play a central role in the detoxification of carcinogens, including PAHs. We investigated the association between colorectal cancer and three variants (CYP1A1*2A, CYP1A1*2C, CYP1A1*4) of the CYP1A1 gene, and homozygosity for the null deletion of the GSTM1 and GSTT1 genes, and the joint effects of these genotypes and smoking, meat intake and intake of green leafy vegetables in a population-based study of 264 cases and 408 controls in Northeast Scotland. There was an inverse association with the CYP1A1*4 (m4) variant (OR 0.3, 95% CI 0.13-0.70). The OR for the CYP1A1*2C (m2) variant was 1.3 (95% CI 0.59-2.91), which is similar to a combined estimate for previous studies (OR 1.2, 95% CI 0.95-1.41). We observed no association with the CYP1A1*2A (m1) variant, or the GSTM1 and GSTT1 polymorphisms. Significant interactions between all 3 CYP1A1 variants and meat intake, and between the m1 and m2 variants and intake of green leafy vegetables, were observed. There was no evidence of interaction between CYP1A1 and smoking, and no evidence of interaction between the GSTM1 or GSTT1 polymorphisms and smoking, meat intake, green leafy vegetable intake, CYP1A1 variants or each other.

  17. Aryl hydrocarbon-induced interactions at multiple DNA elements of diverse sequence--a multicomponent mechanism for activation of cytochrome P4501A1 (CYP1A1) gene transcription.

    PubMed Central

    Robertson, R W; Zhang, L; Pasco, D S; Fagan, J B

    1994-01-01

    In vivo footprinting experiments, augmented with gel shift and transfection analyses suggest that activation of the CYP1A1 gene by aryl hydrocarbons may be a multicomponent process. During the first 30 minutes of exposure to aryl hydrocarbon carcinogens and environmental contaminants, in vivo footprints appear at nine distinct sites within a 281 bp region centered 950 bp upstream of the CYP1A1 transcription start site. Six of these sites are unrelated in sequence to the three xenobiotic response elements (XREs) within this region, at which the aryl hydrocarbon (AH) receptor is known to bind. These six display a variety of footprint patterns, are diverse in sequence and range in G-C content from 60 to 75%. This diversity suggests that multiple nuclear factors may be responsible for these six in vivo footprints. These observations are consistent with competition gel shift experiments showing that the nuclear factors binding at two of these sites are different from each other, as well as from the AH receptor. Gel shifts also indicate that the sequence-specific factors binding at these sites are expressed constitutively. This is consistent with a model in which in vivo footprints are induced at these six sites, not through direct activation or de novo synthesis of DNA-binding factors, but through a two phase mechanism in which binding of the nuclear AH receptor complex to XREs facilitates the binding of constitutive factors at these sites. This facilitation could be mediated either through specific protein-protein interactions or through alterations in chromatin structure that make these sites accessible to constitutive nuclear factors. A function for the sequences at which aryl hydrocarbons induce in vivo footprints is suggested by transfection experiments showing that one of these sequences cooperates with a weak XRE to confer on a reporter gene responsiveness to aryl hydrocarbons. Images PMID:8202380

  18. Differences in the action of lower and higher chlorinated polychlorinated naphthalene (PCN) congeners on estrogen dependent breast cancer cell line viability and apoptosis, and its correlation with Ahr and CYP1A1 expression.

    PubMed

    Gregoraszczuk, Ewa L; Barć, Justyna; Falandysz, Jerzy

    2016-07-29

    There are data showing that exposition to PCNs mixture increased incidence of gastrointestinal and respiratory neoplasms, but data regarding incidence of hormone-dependent cancer so far not shown. The objective was to determine if exposure to single lower and higher chlorinated PCN congeners is associated with altered proliferation and apoptosis of estrogen dependent breast cancer cells, and whether such effects are related to induction of AhR and CYP1A1 protein expression. MCF-7 cells were exposed to PCN 34, 39, 42, 46, 48, 52, 53, 54, 66, 67, 70, 71, 73 and 74 at concentrations of 100-10,000pg/ml. We evaluated the action of these PCN congeners on cell proliferation, DNA fragmentation and caspase-8,-9 activity. AhR and CYP1A1 protein expression and CYP1A1 activity was evaluated at a concentration of 1000pg/ml. An opposite action of tri- to tetraCNs than of penta-to heptaCNs on cell proliferation and apoptosis was evident. Tetra PCNs increased cell proliferation, but had no effect on DNA fragmentation nor caspase activity. Fast induction of CYP1A1 protein expression under the influence of lower chlorinated PCNs suggests faster metabolism and a possible stimulatory action of locally formed metabolites on cell proliferation. None of the higher chlorinated PCNs affected cell proliferation but all higher chlorinated PCNs increased caspase-8 activity, and hexa PCNs also increased caspase-9 activity. The rapid activation of the Ah receptor and CYP1A1 protein expression by higher chlorinated PCNs point to their toxicity; however, it is not sufficient for potential carcinogenicity. Action of lower chlorinated naphthalenes metabolites should be explored.

  19. Epigenetic Determinants of CYP1A1 Induction by the Aryl Hydrocarbon Receptor Agonist 3,3',4,4',5-Pentachlorobiphenyl (PCB 126)

    PubMed Central

    Vorrink, Sabine U.; Hudachek, Danielle R.; Domann, Frederick E.

    2014-01-01

    Many enzymes involved in xenobiotic metabolism, including cytochrome P450 (CYP) 1A1, are regulated by the aryl hydrocarbon receptor (AhR). 3,3',4,4',5-Pentachlorobiphenyl (PCB 126) is a potent ligand for AhR and can thus induce the expression of CYP1A1. Interestingly, we observed that human carcinoma cell lines derived from different types of epithelial cells displayed divergent degrees of CYP1A1 induction after exposure to PCB 126. Since epigenetic mechanisms are known to be involved in cell type-specific gene expression, we sought to assess the epigenetic determinants of CYP1A1 induction in these carcinoma cell lines. In contrast to HepG2 hepatocarcinoma cells, HeLa cervical carcinoma cells showed significantly lower levels of CYP1A1 mRNA expression following PCB 126 exposure. Our results show that the two cell lines maintained differences in the chromatin architecture along the CYP1A1 promoter region. Furthermore, treatment with the epigenetic modifiers, trichostatin A (TSA) and 5-aza-2'-deoxycytidine (5-Aza-dC), significantly increased the expression of CYP1A1 after PCB 126 treatment in HeLa cells. However, we did not observe apparent differences in methylation levels or specific location of CpG DNA methylation between the two cell lines in the analyzed CYP1A1 promoter region. Taken together, our findings suggest that the differences in CYP1A1 expression between HepG2 and HeLa cells are due to differences in the chromatin architecture of the CYP1A1 promoter and thus establish a role of epigenetic regulation in cell-specific CYP1A1 expression. PMID:25116688

  20. The aryl hydrocarbon receptor-interacting protein (AIP) is required for dioxin-induced hepatotoxicity but not for the induction of the Cyp1a1 and Cyp1a2 genes.

    PubMed

    Nukaya, Manabu; Lin, Bernice C; Glover, Edward; Moran, Susan M; Kennedy, Gregory D; Bradfield, Christopher A

    2010-11-12

    The aryl hydrocarbon receptor (AHR) plays an essential role in the toxic response to environmental pollutants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), in the adaptive up-regulation of xenobiotic metabolizing enzymes, and in hepatic vascular development. In our model of AHR signaling, the receptor is found in a cytosolic complex with a number of molecular chaperones, including Hsp90, p23, and the aryl hydrocarbon receptor-interacting protein (AIP), also known as ARA9 and XAP2. To understand the role of AIP in adaptive and toxic aspects of AHR signaling, we generated a conditional mouse model where the Aip locus can be deleted in hepatocytes. Using this model, we demonstrate two important roles for the AIP protein in AHR biology. (i) The expression of AIP in hepatocytes is essential to maintain high levels of functional cytosolic AHR protein in the mammalian liver. (ii) Expression of the AIP protein is essential for dioxin-induced hepatotoxicity. Interestingly, classical AHR-driven genes show differential dependence on AIP expression. The Cyp1b1 and Ahrr genes require AIP expression for normal up-regulation by dioxin, whereas Cyp1a1 and Cyp1a2 do not. This differential dependence on AIP provides evidence that the mammalian genome contains more than one class of AHR-responsive genes and suggests that a search for AIP-dependent, AHR-responsive genes may guide us to the targets of the dioxin-induced hepatotoxicity.

  1. Methysticin and 7,8-dihydromethysticin are two major kavalactones in kava extract to induce CYP1A1.

    PubMed

    Li, Yan; Mei, Hu; Wu, Qiangen; Zhang, Suhui; Fang, Jia-Long; Shi, Leming; Guo, Lei

    2011-12-01

    Kava is a plant traditionally used for making beverages in Pacific Basin countries and has been used for the treatment of nervous disorders in the United States. The pharmacological activity of kava is achieved through kavalactones in kava extract, which include kawain, 7,8-dihydrokawain, yangonin, 5,6-dehydrokawain, methysticin, and 7,8-dihydromethysticin. Recent studies have shown that kava extract induces hepatic CYP1A1 enzyme; however, the mechanisms of CYP1A1 induction have not been elucidated, and the kavalactones responsible for CYP1A1 induction have not yet been identified. Using a combination of biochemical assays and molecular docking tools, we determined the functions of kava extract and kavalactones and delineated the underlying mechanisms involved in CYP1A1 induction. The results showed that kava extract displayed a concentration-dependent effect on CYP1A1 induction. Among the six major kavalactones, methysticin triggered the most profound inducing effect on CYP1A1 followed by 7,8-dihydromethysticin. The other four kavalactones (yangonin, 5,6-dehydrokawain, kawain, and 7,8-dihydrokawain) did not show significant effects on CYP1A1. Consistent with the experimental results, in silico molecular docking studies based on the aryl hydrocarbon receptor (AhR)-ligand binding domain homology model also revealed favorable binding to AhR for methysticin and 7,8-dihydromethysticin compared with the remaining kavalactones. Additionally, results from a luciferase gene reporter assay suggested that kava extract, methysticin, and 7,8-dihydromethysticin were able to activate the AhR signaling pathway. Moreover, kava extract-, methysticin-, and 7,8-dihydromethysticin-mediated CYP1A1 induction was blocked by an AhR antagonist and abolished in AhR-deficient cells. These findings suggest that kava extract induces the expression of CYP1A1 via an AhR-dependent mechanism and that methysticin and 7,8-dihydromethysticin contribute to CYP1A1 induction. The induction of CYP1A1

  2. Cigarette smoking, dietary habits and genetic polymorphisms in GSTT1, GSTM1 and CYP1A1 metabolic genes: A case-control study in oncohematological diseases

    PubMed Central

    Cerliani, María Belén; Pavicic, Walter; Gili, Juan Antonio; Klein, Graciela; Saba, Silvia; Richard, Silvina

    2016-01-01

    AIM To analyze the association between oncohematological diseases and GSTT1/GSTM1/CYP1A1 polymorphisms, dietary habits and smoking, in an argentine hospital-based case-control study. METHODS This hospital-based case-control study involved 125 patients with oncohematological diseases and 310 control subjects. A questionnaire was used to obtain sociodemographic data and information about habits. Blood samples were collected, and DNA was extracted using salting out methods. Deletions in GSTT1 and GSTM1 (null genotypes) were addressed by PCR. CYP1A1 MspI polymorphism was detected by PCR-RFLP. Odds ratio (OR) and 95%CI were calculated to estimate the association between each variable studied and oncohematological disease. RESULTS Women showed lower risk of disease compared to men (OR 0.52, 95%CI: 0.34-0.82, P = 0.003). Higher levels of education (> 12 years) were significantly associated with an increased risk, compared to complete primary school or less (OR 3.68, 95%CI: 1.82-7.40, P < 0.001 adjusted for age and sex). With respect to tobacco, none of the smoking categories showed association with oncohematological diseases. Regarding dietary habits, consumption of grilled/barbecued meat 3 or more times per month showed significant association with an increased risk of disease (OR 1.72, 95%CI: 1.08-2.75, P = 0.02). Daily consumption of coffee also was associated with an increased risk (OR 1.77, 95%CI: 1.03-3.03, P = 0.03). Results for GSTT1, GSTM1 and CYP1A1 polymorphisms showed no significant association with oncohematological diseases. When analyzing the interaction between polymorphisms and tobacco smoking or dietary habits, no statistically significant associations that modify disease risk were found. CONCLUSION We reported an increased risk of oncohematological diseases associated with meat and coffee intake. We did not find significant associations between genetic polymorphisms and blood cancer. PMID:27777882

  3. TSU-16, (Z)-3-[(2,4-dimethylpyrrol-5-yl)methylidenyl]-2-indolinone, is a potent activator of aryl hydrocarbon receptor and increases CYP1A1 and CYP1A2 expression in human hepatocytes.

    PubMed

    Matsuoka-Kawano, Kazuaki; Yoshinari, Kouichi; Nagayama, Sekio; Yamazoe, Yasushi

    2010-04-15

    (Z)-3-[(2,4-dimethylpyrrol-5-yl)methylidenyl]-2-indolinone (TSU-16), is a potent anti-angiogenic agent that inhibits the tyrosine kinase of vascular endothelial growth factor receptor-2. In clinical trials with daily or twice weekly intravenous administration of TSU-16, its increased clearance was observed. To understand the mechanism underlying this observation, we have investigated the TSU-16-mediated regulation of cytochrome P450 expression. In human hepatocytes, TSU-16 increased mRNA levels of CYP1A1 and CYP1A2, but not CYP2B6 and CYP3A4. The extent of increase and profiles of the time-dependent changes in CYP1A1 and CYP1A2 mRNA levels after TSU-16 treatment were similar to those after treatment with 3-methylcholanthrene (3MC), a well-known activator of the aryl hydrocarbon receptor (AhR). In reporter assays using a plasmid construct that contained the human CYP1A1 5'-flanking region including the region crucial for the AhR-dependent transcription of both human CYP1A1 and CYP1A2, TSU-16 treatment increased reporter activities to an extent similar to that obtained with 3MC. Treatment of HepG2 cells and human hepatocytes with AhR-targeting siRNA suppressed the increase in both mRNA levels and CYP1A activities after treatment with TSU-16 as well as after that with omeprazole or 3MC. TSU-16 also time-dependently reduced cellular AhR protein levels in HepG2 cells to a similar extent with 3MC treatment. Furthermore, we demonstrated that unlabeled TSU-16 and 3MC but not omeprazole completely inhibited the specific binding of [(3)H]-3MC to mouse Hepa1c1c7 cytosol, suggesting TSU-16 as an AhR ligand. In conclusion, our present results suggest that TSU-16 binds to and activates AhR to enhance the expression of both human CYP1A1 and CYP1A2. Because TSU-16 is metabolized mainly by CYP1A2, its increased clearance after repeated dosing may be attributed to the enhanced expression of hepatic CYP1A2.

  4. Maternal protein restriction during lactation modulated the expression and activity of rat offspring hepatic CYP1A1, CYP1A2, CYP2B1, CYP2B2, and CYP2E1 during development

    PubMed Central

    Da Costa, N. Meireles; Visoni, S.B.C.; Dos Santos, I.L.; Barja-Fidalgo, T.C.; Ribeiro-Pinto, L.F.

    2016-01-01

    Early nutrition plays a long-term role in the predisposition to chronic diseases and influences the metabolism of several drugs. This may happen through cytochromes P450 (CYPs) regulation, which are the main enzymes responsible for the metabolism of xenobiotics. Here, we analyzed the effects of maternal protein restriction (MPR) on the expression and activity of hepatic offspring’s CYPs during 90 days after birth, using Wistar rats as a mammal model. Hepatic CYP1A1, CYP1A2, CYP2B1, CYP2B2 and CYP2E1 mRNA and protein expression, and associated catalytic activities (ECOD, EROD, MROD, BROD, PROD and PNPH) were evaluated in 15-, 30-, 60-, and 90-day-old offspring from dams fed with either a 0% protein (MPR groups) or a standard diet (C groups) during the 10 first days of lactation. Results showed that most CYP genes were induced in 60- and 90-day-old MPR offspring. The inductions detected in MPR60 and MPR90 were of 5.0- and 2.0-fold (CYP1A2), 3.7- and 2.0-fold (CYP2B2) and 9.8- and 5.8– fold (CYP2E1), respectively, and a 3.8-fold increase of CYP2B1 in MPR90. No major alterations were detected in CYP protein expression. The most relevant CYP catalytic activities’ alterations were observed in EROD, BROD and PNPH. Nevertheless, they did not follow the same pattern observed for mRNA expression, except for an induction of EROD in MPR90 (3.5-fold) and of PNPH in MPR60 (2.2-fold). Together, these results suggest that MPR during lactation was capable of altering the expression and activity of the hepatic CYP enzymes evaluated in the offspring along development. PMID:27828666

  5. Maternal protein restriction during lactation modulated the expression and activity of rat offspring hepatic CYP1A1, CYP1A2, CYP2B1, CYP2B2, and CYP2E1 during development.

    PubMed

    Da Costa, N Meireles; Visoni, S B C; Dos Santos, I L; Barja-Fidalgo, T C; Ribeiro-Pinto, L F

    2016-01-01

    Early nutrition plays a long-term role in the predisposition to chronic diseases and influences the metabolism of several drugs. This may happen through cytochromes P450 (CYPs) regulation, which are the main enzymes responsible for the metabolism of xenobiotics. Here, we analyzed the effects of maternal protein restriction (MPR) on the expression and activity of hepatic offspring's CYPs during 90 days after birth, using Wistar rats as a mammal model. Hepatic CYP1A1, CYP1A2, CYP2B1, CYP2B2 and CYP2E1 mRNA and protein expression, and associated catalytic activities (ECOD, EROD, MROD, BROD, PROD and PNPH) were evaluated in 15-, 30-, 60-, and 90-day-old offspring from dams fed with either a 0% protein (MPR groups) or a standard diet (C groups) during the 10 first days of lactation. Results showed that most CYP genes were induced in 60- and 90-day-old MPR offspring. The inductions detected in MPR60 and MPR90 were of 5.0- and 2.0-fold (CYP1A2), 3.7- and 2.0-fold (CYP2B2) and 9.8- and 5.8- fold (CYP2E1), respectively, and a 3.8-fold increase of CYP2B1 in MPR90. No major alterations were detected in CYP protein expression. The most relevant CYP catalytic activities' alterations were observed in EROD, BROD and PNPH. Nevertheless, they did not follow the same pattern observed for mRNA expression, except for an induction of EROD in MPR90 (3.5-fold) and of PNPH in MPR60 (2.2-fold). Together, these results suggest that MPR during lactation was capable of altering the expression and activity of the hepatic CYP enzymes evaluated in the offspring along development.

  6. Cytogenetic damage in Turkish coke oven workers exposed to polycyclic aromatic hydrocarbons: Association with CYP1A1, CYP1B1, EPHX1, GSTM1, GSTT1, and GSTP1 gene polymorphisms.

    PubMed

    Ada, Ahmet Oguz; Demiroglu, Canan; Yilmazer, Meltem; Suzen, Halit Sinan; Demirbag, Ali Eba; Efe, Sibel; Alemdar, Yilmaz; Iscan, Mumtaz; Burgaz, Sema

    2013-09-01

    The aim of this study was to determine the frequencies of chromosomal aberrations (CA) and cytochalasin-blocked micronuclei (CBMN) in peripheral blood lymphocytes from Turkish coke oven workers and the influence of CYP1A1, CYP1B1, EPHX1, GSTM1, GSTT1, and GSTP1 gene polymorphisms on these biomarkers. Cytogenetic analysis showed that occupational exposure significantly increased the CA and CBMN frequencies. Gene polymorphisms, on the other hand, did not affect CA or CBMN in either exposed or control subjects. However, due to the limited sample size, our findings need to be verified in future studies with a larger sample.

  7. Association of polymorphisms in AhR, CYP1A1, GSTM1, and GSTT1 genes with levels of DNA damage in peripheral blood lymphocytes among coke-oven workers

    SciTech Connect

    Yongwen Chen; Yun Bai; Jing Yuan; Weihong Chen; Jianya Sun; Hong Wang; Huashan Liang; Liang Guo; Xiaobo Yang; Hao Tan; Yougong Su; Qingyi Wei; Tangchun Wu

    2006-09-15

    Accumulating evidence has shown that both DNA damage caused by the metabolites of polycyclic aromatic hydrocarbons (PAH) and genetic polymorphisms in PAH-metabolic genes contribute to individual susceptibility to PAH-induced carcinogenesis. However, the functional relevance of genetic polymorphisms in PAH-metabolic genes in exposed individuals is still unclear. In this study of 240 coke-oven workers (the exposed group) and 123 non-coke-oven workers (the control group), we genotyped for polymorphisms in the AhR, CYP1A1, GSTM1, and GSTT1 genes by PCR methods, and determined the levels of DNA damage in peripheral blood lymphocytes using the alkaline comet assay. It was found that the ln-transformed Olive tail moment (Olive TM) values in the exposed group were significantly higher than those in the control group. Furthermore, in the exposed group, the Olive TM values in subjects with the AhR Lys{sup 554} variant genotype were higher than those with the AhR Arg{sup 554}/Arg{sup 554} genotype. Similarly, the Olive TM values in the non-coke-oven workers with the CYP1A1 MspI CC + CT genotype were lower than the values of those with the CYP1A1 MspI TT genotype. However, these differences were not evident for GSTM1 and GSTT1. These results suggested that the polymorphism of AhR might modulate the effects of PAHs in the exposed group; however, the underlying molecular mechanisms by which this polymorphism may have affected the levels of PAH-induced DNA damage warrant further investigation.

  8. Application of homology modeling to generate CYP1A1 mutants with enhanced activation of the cancer chemotherapeutic prodrug dacarbazine.

    PubMed

    Lewis, Benjamin C; Mackenzie, Peter I; Miners, John O

    2011-11-01

    The chemotherapeutic prodrug dacarbazine (DTIC) has limited efficacy in human malignancies and exhibits numerous adverse effects that arise from systemic exposure to the cytotoxic metabolite. DTIC is activated by CYP1A1 and CYP1A2 catalyzed N-demethylation. However, structural features of these enzymes that confer DTIC N-demethylation have not been characterized. A validated homology model of CYP1A1 was employed to elucidate structure-activity relationships and to engineer CYP1A1 enzymes with altered DTIC activation. In silico docking demonstrated that DTIC orientates proximally to Ser122, Phe123, Asp313, Ala317, Ile386, Tyr259, and Leu496 of human CYP1A1. The site of metabolism is positioned 5.6 Å from the heme iron at an angle of 105.3°. Binding in the active site is stabilized by H-bonding between Tyr259 and the N(2) position of the imidazole ring. Twenty-seven CYP1A1 mutants were generated and expressed in Escherichia coli in yields ranging from 9 to 225 pmol P450/mg. DTIC N-demethylation by the E161K, E256K, and I458V mutants exhibited Michaelis-Menten kinetics, with decreases in K(m) (183-249 μM) that doubled the catalytic efficiency (p < 0.05) relative to wild-type CYP1A1 (K(m), 408 ± 43 μM; V(max), 28 ± 4 pmol · min(-1) · pmol of P450(-1)). The generation of enzymes with catalytically enhanced DTIC activation highlights the potential use of mutant CYP1A1 proteins in P450-based gene-directed enzyme prodrug therapy for the treatment of metastatic malignant melanoma.

  9. Changes in persistent contaminant concentration and CYP1A1 protein expression in biopsy samples from northern bottlenose whales, Hyperoodon ampullatus, following the onset of nearby oil and gas development.

    PubMed

    Hooker, Sascha K; Metcalfe, Tracy L; Metcalfe, Chris D; Angell, Carolyn M; Wilson, Joanna Y; Moore, Michael J; Whitehead, Hal

    2008-03-01

    A small population of endangered northern bottlenose whales (Hyperoodon ampullatus) inhabits "The Gully" a Marine Protected Area on the Scotian Shelf, eastern Canada. Amid concerns regarding nearby oil and gas development, we took 36 skin and blubber biopsy samples in 1996-1997 (prior to major development) and 2002-2003 (five years after development began), and three samples from a population in the Davis Strait, Labrador in 2003. These were analysed for cytochrome P4501A1 (CYP1A1) protein expression (n=36), and for persistent contaminants (n=23). CYP1A1 showed generally low expression in whales from The Gully, but higher levels during 2003, potentially coincident with recorded oil spills, and higher levels in Davis Strait whales. A range of PCB congeners and organochlorine compounds were detected, with concentrations similar to other North Atlantic odontocetes. Concentrations were higher in whales from The Gully than from the Davis Strait, with significant increases in 4,4'-DDE and trans-nonachlor in 2002-2003 relative to 1996-1997.

  10. [The role of mutation of gene cyp1A1 and benzapilene in cytogenetic changes of urinary tract epitheliocytes in oil industry workers employed in the oil fields of the North of West Siberia].

    PubMed

    Il'inskikh, N N; Il'inskikh, E N; Il'inskikh, I N; Iamkovaia, E V

    2011-01-01

    The examination of 477 oil industry workers and office personnel (control) employed in the oil fields of the North of Tomsk and Tyumen regions has detected increased number of epithelyocytes with micronuclei and an elevated urine level ofbenzapilene in workers employed in oil production. Especially pronounced changes of the above parameters were observed in men with mutant alleles Val of CYP1A1 gene. An enhanced mutation process in oil production workers may be due to a resultant action of different factors on human genome. Involved may be both mutagens and factors of comutagenic nature. The results obtained in this study suggest a conclusion about urgent need of introduction of new scientifically validated criteria of selection of personnel for oil production in the North of the West Siberia. Health examination of the applicants must include genotyping.

  11. Retinoids repress Ah receptor CYP1A1 induction pathway through the SMRT corepressor.

    PubMed

    Fallone, Frédérique; Villard, Pierre-Henri; Sérée, Eric; Rimet, Odile; Nguyen, Quock Binh; Bourgarel-Rey, Véronique; Fouchier, Francis; Barra, Yves; Durand, Alain; Lacarelle, Bruno

    2004-09-17

    CYP1A1 isoform is mainly regulated by the transcription factor AhR and to a lesser extent by the nuclear receptor RAR. The effect of a coexposure with 3MC, a AhR ligand, and RA, a RAR ligand, which are, respectively, strong and weak CYP1A1 inducers, is poorly known. We showed in Caco-2 cells that addition of RA significantly decreased 3MC-induced CYP1A1 expression by -55% for mRNA level and -30% for promoter and enzymatic activities. We further showed that RA decreased AhR protein level. Moreover, a physical interaction between AhR and the RAR-corepressor SMRT has been described in vitro. Using the corepressor inhibitor TSA, transfected-cells with SMRT cDNA, and coimmunoprecipitation experiments, we demonstrated that RA addition repressed AhR function through a marked AhR/SMRT physical interaction. This interaction explains the decrease of 3MC-induced CYP1A1 expression. This new mechanism involving the repression of AhR-induced CYP1A1 expression by retinoids allows better knowledge of the CYP1A1 regulation.

  12. Genome-Wide RNAi High-Throughput Screen Identifies Proteins Necessary for the AHR-Dependent Induction of CYP1A1 by 2,3,7,8-Tetrachlorodibenzo-p-dioxin

    PubMed Central

    Hankinson, Oliver

    2013-01-01

    The aryl hydrocarbon receptor (AHR) has a plethora of physiological roles, and upon dysregulation, carcinogenesis can occur. One target gene of AHR encodes the xenobiotic and drug-metabolizing enzyme CYP1A1, which is inducible by the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) via the AHR. An siRNA library targeted against over 5600 gene candidates in the druggable genome was used to transfect mouse Hepa-1 cells, which were then treated with TCDD, and subsequently assayed for CYP1A1-dependent ethoxyresorufin-o-deethylase (EROD) activity. Following redundant siRNA activity (RSA) statistical analysis, we identified 93 hits that reduced EROD activity with a p value ≤ .005 and substantiated 39 of these as positive hits in a secondary screening using endoribonuclease-prepared siRNAs (esiRNAs). Twelve of the corresponding gene products were subsequently confirmed to be necessary for the induction of CYP1A1 messenger RNA by TCDD. None of the candidates were deficient in aryl hydrocarbon nuclear translocator expression. However 6 gene products including UBE2i, RAB40C, CRYGD, DCTN4, RBM5, and RAD50 are required for the expression of AHR as well as for induction of CYP1A1. We also found 2 gene products, ARMC8 and TCF20, to be required for the induction of CYP1A1, but our data are ambiguous as to whether they are required for the expression of AHR. In contrast, SIN3A, PDC, TMEM5, and CD9 are not required for AHR expression but are required for the induction of CYP1A1, implicating a direct role in Cyp1a1 transcription. Our methods, although applied to Cyp1a1, could be modified for identifying proteins that regulate other inducible genes. PMID:23997114

  13. Chenodeoxycholic acid increases the induction of CYP1A1 in HepG2 and H4IIE cells

    PubMed Central

    IBRAHIM, ZEIN SHABAN

    2015-01-01

    Bile acids are considered to promote carcinogenesis. Cytochrome P450 1A1 (CYP1A1) plays a critical role in the biotransformation of drugs and procarcinogens. This study aimed to investigate the ability of bile acids to modulate CYP1A1 expression. Treatment of HepG2 cells with chenodeoxycholic acid (CDCA) and Sudan III (S.III) upregulated CYP1A1 transcriptional activity in HepG2 cells and CYP1A1 mRNA expression in H4IIE cells. Pretreatment of the HepG2 and H4IIE cells with CDCA upregulated the S.III-induced CYP1A transcriptional activity and mRNA expression. The CDCA-induced enhancement of CYP1A1 was not abolished by the p38 inhibitor SB203580. However, exposure of the cells to the mitogen-activated protein kinase kinase (MEK)1/2 inhibitor PD98059 suppressed the CDCA-induced enhancement of CYP1A1. These results show the ability of CDCA to upregulate CYP1A1 transcription and expression, which may explain the hepatocarcinogenesis-inducing effect of cholestasis. The CDCA-induced upregulation of CYP1A1 most probably proceeded through MEK1/2 activation, indicating that this may be a therapeutic target to prevent the cancer-promoting effects of excessive amounts of bile acids. PMID:26640583

  14. Distribution of composite CYP1A1 genotypes in Africans, African-Americans and Caucasians.

    PubMed

    Garte, S J; Trachman, J; Crofts, F; Toniolo, P; Buxbaum, J; Bayo, S; Taioli, E

    1996-01-01

    We present the genotype distribution of the CYP1A1 gene in a sample of over 300 subjects of various ethnic origins. Genotypes are presented as composites of eight possible alleles, taking into account the three major polymorphisms, including a recently described African-American-specific MspI RFLP. A new nomenclature system is presented for clarifying the various haplotypes. Interesting interracial differences in allelic frequencies and admixture rates were observed for the three polymorphisms. Because of the importance of the CYP1A1 gene (which encodes the aromatic hydrocarbon hydroxylase) as a biomarker of genetic susceptibility to environmental carcinogens such as polycyclic aromatic hydrocarbons, these data may provide a useful reference for future studies of relationships between CYP1A1 genotype and disease susceptibility.

  15. Alteration in the Expression of Cytochrome P450s (CYP1A1, CYP2E1, and CYP3A11) in the Liver of Mouse Induced by Microcystin-LR

    PubMed Central

    Zhang, Bangjun; Liu, Yang; Li, Xiaoyu

    2015-01-01

    Microcystins (MCs) are cyclic heptapeptide toxins and can accumulate in the liver. Cytochrome P450s (CYPs) play an important role in the biotransformation of endogenous substances and xenobiotics in animals. It is unclear if the CYPs are affected by MCs exposure. The objective of this study was to evaluate the effects of microcystin-LR (MCLR) on cytochrome P450 isozymes (CYP1A1, CYP2E1, and CYP3A11) at mRNA level, protein content, and enzyme activity in the liver of mice the received daily, intraperitoneally, 2, 4, and 8 µg/kg body weight of MCLR for seven days. The result showed that MCLR significantly decreased ethoxyresorufin-O-deethylase (EROD) (CYP1A1) and erythromycin N-demthylase (ERND) (CYP3A11) activities and increased aniline hydroxylase (ANH) activity (CYP2E1) in the liver of mice during the period of exposure. Our findings suggest that MCLR exposure may disrupt the function of CYPs in liver, which may be partly attributed to the toxicity of MCLR in mice. PMID:25831226

  16. Organ-Specific Roles of CYP1A1 during Detoxication of Dietary Benzo[a]pyrene

    PubMed Central

    Shi, Zhanquan; Dragin, Nadine; Gálvez-Peralta, Marina; Jorge-Nebert, Lucia F.; Miller, Marian L.; Wang, Bin

    2010-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are widely distributed environmental toxicants derived from sources that include cigarette smoke, petroleum distillation, gas- and diesel-engine exhaust, and charcoal-grilled food. The gastrointestinal tract is the principal route of PAH exposures, even when inhaled. The most thoroughly studied prototype of PAHs is benzo[a]pyrene (BaP), well known to be toxic, mutagenic, and carcinogenic in various tissues and cell types. This lab has previously shown that Cyp1a1(−/−) global knockout mice treated by oral administration of BaP die at 28 to 32 days with immunosuppression, whereas wild-type mice remain healthy for 1 year on high BaP doses (125 mg/kg/day). Thus, for oral BaP, CYP1A1 is more important in detoxication than in metabolic activation. After several days of oral BaP, we found surprisingly low CYP1A1 levels in liver, compared with that in small intestine; we postulated that this finding might reflect efficient detoxication of oral BaP in proximal small intestine such that significant amounts of the inducer BaP no longer reach the liver. In the present study, many parameters were therefore compared in wild-type, Cyp1a1(−/−) global knockout, intestinal epithelial cell-specific Cyp1a1 knockout, and hepatocyte-specific Cyp1a1 knockout mice as a function of long-term oral exposure to BaP. The peak of CYP1A1 (mRNA, protein) expression in liver occurred at 12 h, whereas highly induced CYP1A1 in small intestine persisted throughout the 30-day experiment. Hepatocyte-specific Cyp1a1 knockout mice remained as healthy as wild-type mice; intestinal epithelial cell-specific Cyp1a1 knockout mice behaved like Cyp1a1(−/−) mice, dying with immunosuppression ∼30 days on oral BaP. We conclude that small intestine CYP1A1, and not liver CYP1A1, is critically important in oral BaP detoxication. PMID:20371670

  17. Phenotype of the Cyp1a1/1a2/1b1(−/−) Triple-Knockout Mouse*

    PubMed Central

    Dragin, Nadine; Shi, Zhanquan; Madan, Rajat; Karp, Christopher L.; Sartor, Maureen A.; Chen, Chi; Gonzalez, Frank J.; Nebert, Daniel W.

    2009-01-01

    Crossing the Cyp1a1/1a2(−/−) double-knockout mouse with the Cyp1b1(−/−) single-knockout mouse, we generated the Cyp1a1/1a2/1b1(−/−) triple-knockout mouse. In this triple-knockout mouse, statistically significant phenotypes (with incomplete penetrance) included slower weight gain and greater risk of embryolethality before gestational day 11, hydrocephalus, hermaphroditism, and cystic ovaries. Oral benzo[a]pyrene (BaP) daily for 18 days in the Cyp1a1/1a2(−/−) produced the same degree of marked immunosuppression as seen in the Cyp1a1(−/−) mouse; we believe this reflects the absence of intestinal CYP1A1. Oral BaP-treated Cyp1a1/1a2/1b1(−/−) mice showed the same “rescued” response as that seen in the Cyp1a1/1b1(−/−) mouse; we believe this reflects the absence of CYP1B1 in immune tissues. Urinary metabolite profiles were dramatically different between untreated triple-knockout and wild-type; principal components analysis showed that the shifts in urinary metabolite patterns in oral BaP-treated triple-knockout and wild-type mice were also strikingly different. Liver microarray cDNA differential expression (comparing triple-knockout with wild-type) revealed at least 89 genes up- and 62 genes down-regulated (P-value ≤0.00086). Gene Ontology “classes of genes” most perturbed in the untreated triple-knockout (compared with wild-type) include lipid, steroid, and cholesterol biosynthesis and metabolism; nucleosome and chromatin assembly; carboxylic and organic acid metabolism; metal-ion binding; and ion homeostasis. In the triple-knockout compared with the wild-type mice, response to zymosan-induced peritonitis was strikingly exaggerated, which may well reflect down-regulation of Socs2 expression. If a single common molecular pathway is responsible for all of these phenotypes, we suggest that functional effects of the loss of all three Cyp1 genes could be explained by perturbations in CYP1-mediated eicosanoid production, catabolism and

  18. Cytochrome P450 CYP1A1: wider roles in cancer progression and prevention

    PubMed Central

    2009-01-01

    CYP1A1 is one of the main cytochrome P450 enzymes, examined extensively for its capacity to activate compounds with carcinogenic properties. Continuous exposure to inhalation chemicals and environmental carcinogens is thought to increase the level of CYP1A1 expression in extrahepatic tissues, through the aryl hydrocarbon receptor (AhR). Although the latter has long been recognized as a ligand-induced transcription factor, which is responsible for the xenobiotic activating pathway of several phase I and phase II metabolizing enzymes, recent evidence suggests that the AhR is involved in various cell signaling pathways critical to cell cycle regulation and normal homeostasis. Disregulation of these pathways is implicated in tumor progression. In addition, it is becoming increasingly evident that CYP1A1 plays an important role in the detoxication of environmental carcinogens, as well as in the metabolic activation of dietary compounds with cancer preventative activity. Ultimately the contribution of CYP1A1 to cancer progression or prevention may depend on the balance of procarcinogen activation/detoxication and dietary natural product extrahepatic metabolism. PMID:19531241

  19. Inhibition of 17β-estradiol activation by CYP1A1: genotype- and regioselective inhibition by St. John's Wort and several natural polyphenols.

    PubMed

    Schwarz, Dieter; Kisselev, Pyotr; Schunck, Wolf-Hagen; Roots, Ivar

    2011-01-01

    Several epidemiological studies associate certain CYP1A1 genotypes, alone or in combination, with an increased risk of estrogen-related cancers. Previously we demonstrated that metabolic activation of estrogens by CYP1A1 is a genotype-dependent reaction with the CYP1A1.2 (Ile462Val) variant being the most efficient catalyst (Kisselev et al.). To answer the question whether genotype-dependent inhibition of activation of estrogens by CYP1A1 could also contribute, we studied the inhibition of hydroxylation activity of the most common allelic variants of human CYP1A1 towards 17β-estradiol. We expressed and purified CYP1A1.1 (wild-type), CYP1A1.2 (Ile462Val), and CYP1A1.4 (Thr461Asn) and performed inhibition assays by natural polyphenols of our diet and drugs of NADPH-dependent estradiol hydroxylation in reconstituted CYP1A1 systems. From the polyphenols studied, a St. John's Wort (Hypericum perforatum) extract, some of its main single constituents hypericin, pseudohypericin, and quercetin, as well as the flavonols kaempferol, myricetin and the phytoestrogens resveratrol and tetramethyl-stilbene exhibited strong inhibition. For the St. John's Wort extract and its single constituents hypericin, pseudohypericin, and quercetin, inhibition exhibited a remarkable dependency on the CYP1A1 genotype. Whereas (wild-type) CYP1A1.1 was most inhibited by the whole crude extract, the variant CYP1A1.2 (Ile462Val) was significantly stronger inhibited by the constituents in its pure form: IC₅₀ values for 2-hydroxylation was more than two times lower compared with the wild-type enzyme and the variant CYP1A1.4 (Thr461Asn). Besides this, the inhibition exhibited a remarkable regioselectivity. The data suggest that risk of estrogen-mediated diseases might be not only influenced by CYP1A1 genotype-dependent activation but also its inhibition by natural polyphenols of our diet and drugs.

  20. Phenylthiourea as a weak activator of aryl hydrocarbon receptor inhibiting 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced CYP1A1 transcription in zebrafish embryo.

    PubMed

    Wang, Wen-Der; Wang, Yin; Wen, Hui-Ju; Buhler, Donald R; Hu, Chin-Hwa

    2004-07-01

    The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that can be activated by a diverse synthetic and naturally-occurring chemicals, such as the halogenated aromatic hydrocarbons (HAHs) and the non-halogenated polycyclic aromatic hydrocarbons (PAHs). The liganded AHR modulates the genetic activity of a variety of xenobiotic-responsive genes, including cytochrome P4501A1 (CYP1A1). The tyrosinase inhibitor 1-phenyl-2-thiourea (PTU) is widely used in zebrafish research to suppress pigmentation in developing embryos/fry. Here we showed that 0.2 mM PTU induced a basal level of CYP1A1 transcription in zebrafish embryonic integument as early as 24 h postfertilization (hpf) stage. Subsequently, PTU induced CYP1A1 transcription in blood vessels at 36 hpf. During larval stage, the liver and all pharyngeal arch vessels of PTU-treated embryos exhibited CYP1A1 transcription as well. Comparing to TCDD, PTU induces CYP1A1 transcription with much lower efficacy in zebrafish embryos. Coincubating the embryos with PTU and TCDD led to repressing TCDD-induced CYP1A1 transcription. Mechanistic studies indicated that both of PTU- and TCDD-mediated CYP1A1 transcriptions are modulated by the same AHR-ARNT signaling pathway.

  1. Genome-wide association analysis of coffee drinking suggests association with CYP1A1/CYP1A2 and NRCAM

    PubMed Central

    Amin, N; Byrne, E; Johnson, J; Chenevix-Trench, G; Walter, S; Nolte, I M; Vink, J M; Rawal, R; Mangino, M; Teumer, A; Keers, J C; Verwoert, G; Baumeister, S; Biffar, R; Petersmann, A; Dahmen, N; Doering, A; Isaacs, A; Broer, L; Wray, N R; Montgomery, G W; Levy, D; Psaty, B M; Gudnason, V; Chakravarti, A; Sulem, P; Gudbjartsson, D F; Kiemeney, L A; Thorsteinsdottir, U; Stefansson, K; van Rooij, F J A; Aulchenko, Y S; Hottenga, J J; Rivadeneira, F R; Hofman, A; Uitterlinden, A G; Hammond, C J; Shin, S-Y; Ikram, A; Witteman, J C M; Janssens, A C J W; Snieder, H; Tiemeier, H; Wolfenbuttel, B H R; Oostra, B A; Heath, A C; Wichmann, E; Spector, T D; Grabe, H J; Boomsma, D I; Martin, N G; van Duijn, C M

    2012-01-01

    Coffee consumption is a model for addictive behavior. We performed a meta-analysis of genome-wide association studies (GWASs) on coffee intake from 8 Caucasian cohorts (N=18 176) and sought replication of our top findings in a further 7929 individuals. We also performed a gene expression analysis treating different cell lines with caffeine. Genome-wide significant association was observed for two single-nucleotide polymorphisms (SNPs) in the 15q24 region. The two SNPs rs2470893 and rs2472297 (P-values=1.6 × 10−11 and 2.7 × 10−11), which were also in strong linkage disequilibrium (r2=0.7) with each other, lie in the 23-kb long commonly shared 5′ flanking region between CYP1A1 and CYP1A2 genes. CYP1A1 was found to be downregulated in lymphoblastoid cell lines treated with caffeine. CYP1A1 is known to metabolize polycyclic aromatic hydrocarbons, which are important constituents of coffee, whereas CYP1A2 is involved in the primary metabolism of caffeine. Significant evidence of association was also detected at rs382140 (P-value=3.9 × 10−09) near NRCAM—a gene implicated in vulnerability to addiction, and at another independent hit rs6495122 (P-value=7.1 × 10−09)—an SNP associated with blood pressure—in the 15q24 region near the gene ULK3, in the meta-analysis of discovery and replication cohorts. Our results from GWASs and expression analysis also strongly implicate CAB39L in coffee drinking. Pathway analysis of differentially expressed genes revealed significantly enriched ubiquitin proteasome (P-value=2.2 × 10−05) and Parkinson's disease pathways (P-value=3.6 × 10−05). PMID:21876539

  2. The flavonoid galangin is an inhibitor of CYP1A1 activity and an agonist/antagonist of the aryl hydrocarbon receptor.

    PubMed

    Ciolino, H P; Yeh, G C

    1999-03-01

    The effect of the dietary flavonoid galangin on the metabolism of 7,12-dimethylbenz[a]anthracene (DMBA), the activity of cytochrome P450 1A1 (CYP1A1), and the expression of CYP1A1 in MCF-7 human breast carcinoma cells was investigated. Galangin inhibited the catabolic breakdown of DMBA, as measured by thin-layer chromatography, in a dose-dependent manner. Galangin also inhibited the formation of DMBA-DNA adducts, and prevented DMBA-induced inhibition of cell growth. Galangin caused a potent, dose-dependent inhibition of CYP1A1 activity, as measured by ethoxyresorufin-O-deethylase activity, in intact cells and in microsomes isolated from DMBA-treated cells. Analysis of the inhibition kinetics by double-reciprocal plot demonstrated that galangin inhibited CYP1A1 activity in a noncompetitive manner. Galangin caused an increase in the level of CYP1A1 mRNA, indicating that it may be an agonist of the aryl hydrocarbon receptor, but it inhibited the induction of CYP1A1 mRNA by DMBA or by 2,3,5,7-tetrachlorodibenzo-p-dioxin (TCDD). Galangin also inhibited the DMBA- or TCDD-induced transcription of a reporter vector containing the CYP1A1 promoter. Thus, galangin is a potent inhibitor of DMBA metabolism and an agonist/antagonist of the AhR, and may prove to be an effective chemopreventive agent.

  3. CYP1A1, CYP2E1 and EPHX1 polymorphisms in sporadic colorectal neoplasms

    PubMed Central

    Fernandes, Glaucia Maria M; Russo, Anelise; Proença, Marcela Alcântara; Gazola, Nathalia Fernanda; Rodrigues, Gabriela Helena; Biselli-Chicote, Patrícia Matos; Silva, Ana Elizabete; Netinho, João Gomes; Pavarino, Érika Cristina; Goloni-Bertollo, Eny Maria

    2016-01-01

    AIM To investigate the contribution of polymorphisms in the CYP1A1, CYP2E1 and EPHX1 genes on sporadic colorectal cancer (SCRC) risk. METHODS Six hundred forty-one individuals (227 patients with SCRC and 400 controls) were enrolled in the study. The variables analyzed were age, gender, tobacco and alcohol consumption, and clinical and histopathological tumor parameters. The CYP1A1*2A, CYP1A1*2C CYP2E1*5B and CYP2E1*6 polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The EPHX1 Tyr113His, EPHX1 His139Arg and CYP1A1*2C polymorphisms were detected by real-time PCR. Chi-squared test and binary logistic regression were used in the statistical analysis. Haplotype analysis was conducted using the Haploview program, version 2.05. RESULTS Age over 62 years was a risk factor for SCRC development (OR = 7.54, 95%CI: 4.94-11.50, P < 0.01). Male individuals were less susceptible to SCRC (OR = 0.55, 95%CI: 0.35-0.85, P < 0.01). The CYP2E1*5B polymorphism was associated with SCRC in the codominant (heterozygous genotype: OR = 2.66, 95%CI: 1.64-4.32, P < 0.01), dominant (OR = 2.82, 95%CI: 1.74-4.55, P < 0.01), overdominant (OR = 2.58, 95%CI: 1.59-4.19, P < 0.01), and log-additive models (OR = 2.84, 95%CI: 1.78-4.52, P < 0.01). The CYP2E1*6 polymorphism was associated with an increased SCRC risk in codominant (heterozygous genotype: OR = 2.81, 95%CI: 1.84-4.28, P < 0.01; homozygous polymorphic: OR = 7.32, 95%CI: 1.85-28.96, P < 0.01), dominant (OR = 2.97, 95%CI: 1.97-4.50, P < 0.01), recessive (OR = 5.26, 95%CI: 1.35-20.50, P = 0.016), overdominant (OR = 2.64, 95%CI: 1.74-4.01, P < 0.01), and log-additive models (OR = 2.78, 95%CI: 1.91-4.06, P < 0.01). The haplotype formed by the minor alleles of the CYP2E1*5B (C) and CYP2E1*6 (A) polymorphisms was associated with SCRC (P = 0.002). However, the CYP1A1*2A, CYP1A1*2C, EPHX1 Tyr113His and EPHX1 His139Arg polymorphisms were not associated with SCRC. CONCLUSION In conclusion, the

  4. CYP1A1 and CYP1B1 polymorphisms and their association with estradiol and estrogen metabolites in women who are premenopausal and perimenopausal.

    PubMed

    Sowers, MaryFran R; Wilson, Angela L; Kardia, Sharon R; Chu, Jian; McConnell, Daniel S

    2006-09-01

    The purpose of this study was to relate measured concentrations of estradiol (E2) and the urinary estrogen metabolites 2-hydroxyestrone (2-OHE1) and 16alpha-hydroxyestrone (16alpha-OHE1) to single nucleotide polymorphisms (SNPs) from CYP1A1 and CYP1B1, the primary genes involved in estrogen catabolism. We investigated the association of 4 CYP1A1 SNPs (CYP1A1 rs4646903, CYP1A1 rs1531163, CYP1A1 rs2606345, and CYP1A1 rs1048943) and 2 CYP1B1 SNPs (CYP1B1 rs162555 and CYP1B1 rs1056836) to circulating serum E2 concentrations and the urinary estrogen metabolites 2-OHE1 and 16alpha-OHE1. The associations were evaluated in 1,340 participants of 4 racial/ethnic groups from the Study of Women's Health Across the Nation (SWAN) who were premenopausal and perimenopausal. There was substantial variation in the allele frequencies of the SNPs for African American and Caucasian women. There was, however, remarkable comparability between Chinese and Japanese women; their CYP1A1 and CYP1B1 allele frequencies differed by only < or =11%. There was significant variation in E2 concentrations by genotype within racial/ethnic group for CYP1A1 rs2606345. In particular, Japanese women with the CC genotype had lower E2 concentrations than did Japanese women with the AC genotype. Chinese women with the CC genotype had higher 2-OHE1 concentrations than did Chinese women with the AC genotype. Further, African American women with the CC genotype had higher 16alpha-OHE1 concentrations than did those with other genotypes. CYP1A1 rs2606345 may play an important role in estrogen metabolism in women who are premenopausal and perimenopausal.

  5. CYP1A1 polymorphism interactions with smoking status in oral cancer risk: evidence from epidemiological studies.

    PubMed

    Yu, Kai-Tao; Ge, Cheng; Xu, Xiao-Fang; Zou, Jing-Cai; Zou, Xuan; Zhen, Shuai

    2014-11-01

    The cytochrome CYP1A1 gene has been implicated in the etiology of oral cancer. However, the results have been inconsistent. In this study, a meta-analysis was performed to clarify the associations of polymorphisms in CYP1A1 gene with oral cancer risk. Published literatures from PubMed, MEDLINE, EMBASE, and China National Knowledge infrastructure (CNKI) databases were retrieved. A total of 12 studies were included in this meta-analysis. We found that significant positive associations between CYP1A1*2A polymorphism and oral cancer risk in recessive model (CC vs. TC + TT, OR = 1.93), dominant model (CC + TC vs. TT, OR = 1.33), and additive model (CC vs. TT, OR = 1.97). In subgroup analysis based on the ethnicity of study population, significant associations were found in all three genetic models for Asians (recessive OR = 2.29, 95% CI =  .42-3.71; dominant OR = 1.54, 95% CI = 1.03-2.31; additive OR  2.39, 95% CI = 1.47-3.88) but not non-Asians. For the smoking stratification, the result indicated a significant association between CYP1A1*2A polymorphism and oral cancer among the smoking subjects (OR = 1.83, 95% CI = 1.47-2.26). This meta-analysis indicated a marked association of CYP1A1*2A polymorphisms with oral cancer risk, particularly among Asians, whereas there were significant interactions between the polymorphisms and cigarette smoking on oral cancer risk.

  6. Dopamine D2-Receptor Antagonists Down-Regulate CYP1A1/2 and CYP1B1 in the Rat Liver

    PubMed Central

    Harkitis, P.; Lang, M. A.; Marselos, M.; Fotopoulos, A.; Albucharali, G.; Konstandi, M.

    2015-01-01

    Dopaminergic systems regulate the release of several hormones including growth hormone (GH), thyroid hormones, insulin, glucocorticoids and prolactin (PRL) that play significant roles in the regulation of various Cytochrome P450 (CYP) enzymes. The present study investigated the role of dopamine D2-receptor-linked pathways in the regulation of CYP1A1, CYP1A2 and CYP1B1 that belong to a battery of genes controlled by the Aryl Hydrocarbon Receptor (AhR) and play a crucial role in the metabolism and toxicity of numerous environmental toxicants. Inhibition of dopamine D2-receptors with sulpiride (SULP) significantly repressed the constitutive and benzo[a]pyrene (B[a]P)-induced CYP1A1, CYP1A2 and CYP1B expression in the rat liver. The expression of AhR, heat shock protein 90 (HSP90) and AhR nuclear translocator (ARNT) was suppressed by SULP in B[a]P-treated livers, whereas the AhRR expression was increased by the drug suggesting that the SULP-mediated repression of the CYP1 inducibility is due to inactivation of the AhR regulatory system. At signal transduction level, the D2-mediated down-regulation of constitutive CYP1A1/2 and CYP1B1 expression appears to be mediated by activation of the insulin/PI3K/AKT pathway. PRL-linked pathways exerting a negative control on various CYPs, and inactivation of the glucocorticoid-linked pathways that positively control the AhR-regulated CYP1 genes, may also participate in the SULP-mediated repression of both, the constitutive and induced CYP1 expression. The present findings indicate that drugs acting as D2-dopamine receptor antagonists can modify several hormone systems that regulate the expression of CYP1A1, CYP1A2 and CYP1B1, and may affect the toxicity and carcinogenicity outcome of numerous toxicants and pre-carcinogenic substances. Therefore, these drugs could be considered as a part of the strategy to reduce the risk of exposure to environmental pollutants and pre-carcinogens. PMID:26466350

  7. Polychlorinated biphenyls, cytochrome P450 1A1 (CYP1A1) polymorphisms, and breast cancer risk among African American women and white women in North Carolina: a population-based case-control study

    PubMed Central

    Li, Yu; Millikan, Robert C; Bell, Douglas A; Cui, Lisa; Tse, Chiu-Kit J; Newman, Beth; Conway, Kathleen

    2005-01-01

    Introduction Epidemiologic studies have not shown a strong relationship between blood levels of polychlorinated biphenyls (PCBs) and breast cancer risk. However, two recent studies showed a stronger association among postmenopausal white women with the inducible M2 polymorphism in the cytochrome P450 1A1 (CYP1A1) gene. Methods In a population-based case-control study, we evaluated breast cancer risk in relation to PCBs and the CYP1A1 polymorphisms M1 (also known as CYP1A1*2A), M2 (CYP1A1*2C), M3 (CYP1A1*3), and M4 (CYP1A1*4). The study population consisted of 612 patients (242 African American, 370 white) and 599 controls (242 African American, 357 white). Results There was no evidence of strong joint effects between CYP1A1 M1-containing genotypes and total PCBs in African American or white women. Statistically significant multiplicative interactions were observed between CYP1A1 M2-containing genotypes and elevated plasma total PCBs among white women (P value for likelihood ratio test = 0.02). Multiplicative interactions were also observed between CYP1A1 M3-containing genotypes and elevated total PCBs among African American women (P value for likelihood ratio test = 0.10). Conclusions Our results confirm previous reports that CYP1A1 M2-containing genotypes modify the association between PCB exposure and risk of breast cancer. We present additional evidence suggesting that CYP1A1 M3-containing genotypes modify the effects of PCB exposure among African American women. Additional studies are warranted, and meta-analyses combining results across studies will be needed to generate more precise estimates of the joint effects of PCBs and CYP1A1 genotypes. PMID:15642161

  8. Regulation of CYP1A1 by heavy metals and consequences for drug metabolism.

    PubMed

    Anwar-Mohamed, Anwar; Elbekai, Reem H; El-Kadi, Ayman Os

    2009-05-01

    Cytochrome P450 1A1 (CYP1A1) is a hepatic and extrahepatic enzyme that is regulated by the aryl hydrocarbon receptor signaling pathway. With the growing human exposure to heavy metals, emerging evidence suggests that heavy metals exposure alter CYP1A1 enzyme activity. Heavy metals regulate CYP1A1 at different levels of its aryl hydrocarbon receptor signaling pathway in a metal- and species-dependent manner. The importance of CYP1A1 emerges from the fact that it has been always associated with the metabolism of pro-carcinogenic compounds to highly carcinogenic metabolites. However, recently CYP1A1 has gained status along with other cytochrome P450 enzymes in the metabolism of drugs and mediating drug-drug interactions. In addition, CYP1A1 has become a therapeutic tool for the bioactivation of prodrugs, particularly cytotoxic agents. In this review, we shed light on the effect of seven heavy metals, namely arsenic, mercury, lead, cadmium, chromium, copper and vanadium, on CYP1A1 and the consequences on drug metabolism.

  9. Regulation of Human Cytochrome P4501A1 (hCYP1A1): A Plausible Target for Chemoprevention?

    PubMed Central

    Santes-Palacios, Rebeca; Ornelas-Ayala, Diego; Cabañas, Noel; Marroquín-Pérez, Ana; Hernández-Magaña, Alexis; del Rosario Olguín-Reyes, Sitlali

    2016-01-01

    Human cytochrome P450 1A1 (hCYP1A1) has been an object of study due to its role in precarcinogen metabolism; for this reason it is relevant to know more in depth the mechanisms that rule out its expression and activity, which make this enzyme a target for the development of novel chemiopreventive agents. The aim of this work is to review the origin, regulation, and structural and functional characteristics of CYP1A1 letting us understand its role in the bioactivation of precarcinogen and the consequences of its modulation in other physiological processes, as well as guide us in the study of this important protein. PMID:28105425

  10. Differences in 4-hydroxyestradiol levels in leukocytes are related to CYP1A1(∗)2C, CYP1B1(∗)3 and COMT Val158Met allelic variants.

    PubMed

    Martínez-Ramírez, O C; Pérez-Morales, R; Petrosyan, P; Castro-Hernández, C; Gonsebatt, M E; Rubio, J

    2015-10-01

    Exposure to estrogen and its metabolites, including catechol estrogens (CEs) and catechol estrogen quinones (CE-Qs) is closely related to breast cancer. Polymorphisms of the genes involved in the catechol estrogens metabolism pathway (CEMP) have been shown to affect the production of CEs and CE-Qs. In this study, we measured the induction of CYP1A1, CYP1B1, COMT, and GSTP1 by 17β-estradiol (17β-E2) in leukocytes with CYP1A1(∗)2C, CYP1B1(∗)3, COMT Val158Met and GSTP1 Ile105Val polymorphisms by semi quantitative RT-PCR and compared the values to those of leukocytes with wild type alleles; we also compared the differences in formation of 4- hydroxyestradiol (4-OHE2) and DNA-adducts. The data show that in the leukocytes with mutant alleles treatment with 17β-E2 up-regulates CYP1A1 and CYP1B1 and down-regulates COMT mRNA levels, resulting in major increments in 4-OHE2 levels compared to leukocytes with wild-type alleles. Therefore, we propose induction levels of gene expression and intracellular 4-OHE2 concentrations associated with allelic variants in response to exposure of 17β-E2 as a noninvasive biomarker that can help determine the risk of developing non-hereditary breast cancer in women.

  11. Role of CYP1A1 haplotypes in modulating susceptibility to coronary artery disease.

    PubMed

    Lakshmi, Sana Venkata Vijaya; Naushad, Shaik Mohammad; Saumya, Kankanala; Rao, Damera Seshagiri; Kutala, Vijay Kumar

    2012-10-01

    To investigate the role of cytochrome P450 1A1 (CYP1A1) haplotypes in modulating susceptibility to coronary artery disease (CAD), a case-control study was conducted by enrolling 352 CAD cases and 282 healthy controls. PCR-RFLP, multiplex PCR, competitive ELISA techniques were employed for the analysis of CYP1A1 [ml (T-->C), m2 (A-->G) and m4 (C-->A)] haplotypes, glutathione-S-transferase (GST)T1/GSTM1 null variants and plasma 8-oxo-2'deoxyguanosine (8-oxodG) respectively. Two CYP1A1 haplotypes, i.e. CAC and TGC showed independent association with CAD risk, while all-wild CYP1A1 haplotype i.e. TAC showed reduced risk for CAD. All the three variants showed mild linkage disequilibrium (D': 0.05 to 0.17). GSTT1 null variant also exerted independent association with CAD risk (OR: 2.53, 95% CI 1.55-4.12). Among the conventional risk factors, smoking showed synergetic interaction with CAC haplotype of CYP1A1 and GSTT1 null genotype in inflating CAD risk. High risk alleles of this pathway showed dose-dependent association with percentage of stenosis and number of vessels affected. Elevated 8-oxodG levels were observed in subjects with CYP1A1 CAC haplotype and GSTT1 null variant. Multiple linear regression model of these xenobiotic variants explained 36% variability in 8-oxodG levels. This study demonstrated the association of CYP1A1 haplotypes and GSTT1 null variant with CAD risk and this association was attributed to increased oxidative DNA damage.

  12. Inhibition of human and rat CYP1A1 enzyme by grapefruit juice compounds.

    PubMed

    Santes-Palacios, Rebeca; Romo-Mancillas, Antonio; Camacho-Carranza, Rafael; Espinosa-Aguirre, Jesús Javier

    2016-09-06

    Cytochrome P4501A1 is involved in the metabolism of carcinogenic polycyclic aromatic hydrocarbons; therefore, its inhibition interferes with the carcinogenesis process induced by these compounds in rats. The human and rat CYP1A1 differ by 21% in amino acid sequence, including the active site of the enzyme; this difference may be an important factor when results obtained using animal models are interpolated to humans. Based on its previously reported CYP inhibitory properties, we studied the effects of two molecules contained within grapefruit juice, naringenin and 6',7'-dihydroxybergamottin, on human and rat CYP1A1 activity. For this purpose, the kinetics of inhibition as well as computational simulations were used. Naringenin and 6',7'-dihydroxybergamottin were found to be competitive inhibitors of human and rat CYP1A1. Additionally, naringenin exerted a mixed type inhibition effect on rat CYP1A1. Computational docking showed that inhibitors might block the oxidation of 7-ethoxyresorufin by binding to the CYP1A1 active site. Our results demonstrate the differences in CYP inhibitory mechanisms for the same molecule when CYP from different species are considered.

  13. Differential Induction of CYP1A1 and CYP1B1 by Benzo[a]pyrene in Oral Squamous Cell Carcinoma Cell Lines and by Tobacco Smoking in Oral Mucosa

    PubMed Central

    Chi, Angela C.; Appleton, Kathryn; Henriod, Joel B.; Krayer, Joe W.; Marlow, Nicole M.; Bandyopadhyay, Dipankar; Sigmon, Ryan C.; Kurtz, David T.

    2009-01-01

    Polyaromatic hydrocarbons, including benzo[a]pyrene (BP), are major tobacco carcinogens. Their carcinogenic effects require metabolic activation by cytochrome p450 (CYP) enzymes. Relative CYP isoform expression is related to tissue-specific tobacco-related squamous cell carcinoma (SCC) susceptibility. There have been conflicting reports regarding relative CYP1A1 and CYP1B1 oral expression, and information regarding CYP1B1 expression in oral tissues is limited. OBJECTIVE To quantify BP- and tobacco-induced CYP1A1 and CYP1B1 expression in oral SCC cells and oral mucosa. STUDY DESIGN Real-time qPCR was performed to measure 1) BP-induced CYP1A1 and CYP1B1 mRNA expression in seven oral/other head and neck SCC cell lines 2) CYP1A1 and CYP1B1 mRNA expression in gingiva from 22 smokers and 24 nonsmokers. RESULTS SCC lines exhibited either similar induction of both isoforms or preferential CYP1A1 induction (CYP1A1-to-CYP1B1 ratios 0.8-4.3). In contrast, gingival tissues from smokers exhibited preferential CYP1B1 induction. Marked interindividual variation in CYP1A1 and CYP1B1 expression was observed among smokers. CONCLUSIONS In vitro conditions may not account for factors that modulate expression in vivo. Interindividual variation in inducible CYP1A1 and CYP1B1 expression may account in part for variation in tobacco-related oral SCC risk. PMID:19576839

  14. Correlation between CYP1A1 transcript, protein level, enzyme activity and DNA adduct formation in normal human mammary epithelial cell strains exposed to benzo[a]pyrene

    PubMed Central

    Divi, Rao L.; Einem Lindeman, Tracey L.; Shockley, Marie E.; Keshava, Channa; Weston, Ainsley; Poirier, Miriam C.

    2014-01-01

    The polycyclic aromatic hydrocarbon (PAH) benzo(a)pyrene (BP) is thought to bind covalently to DNA, through metabolism by cytochrome P450 1A1 (CYP1A1) and CYP1B1, and other enzymes, to form r7, t8, t9-trihydroxy-c-10-(N 2-deoxyguanosyl)-7,8,9,10-tetrahydro-benzo[a]-pyrene (BPdG). Evaluation of RNA expression data, to understand the contribution of different metabolic enzymes to BPdG formation, is typically presented as fold-change observed upon BP exposure, leaving the actual number of RNA transcripts unknown. Here, we have quantified RNA copies/ng cDNA (RNA cpn) for CYP1A1 and CYP1B1, as well as NAD(P)H:quinone oxidoreductase 1 (NQO1), which may reduce formation of BPdG adducts, using primary normal human mammary epithelial cell (NHMEC) strains, and the MCF-7 breast cancer cell line. In unexposed NHMECs, basal RNA cpn values were 58–836 for CYP1A1, 336–5587 for CYP1B1 and 5943–40112 for NQO1. In cells exposed to 4.0 µM BP for 12h, RNA cpn values were 251–13234 for CYP1A1, 4133–57078 for CYP1B1 and 4456–55887 for NQO1. There were 3.5 (mean, range 0.2–15.8) BPdG adducts/108 nucleotides in the NHMECs (n = 16), and 790 in the MCF-7s. In the NHMECs, BP-induced CYP1A1 RNA cpn was highly associated with BPdG (P = 0.002), but CYP1B1 and NQO1 were not. Western blots of four NHMEC strains, chosen for different levels of BPdG adducts, showed a linear correlation between BPdG and CYP1A1, but not CYP1B1 or NQO1. Ethoxyresorufin-O-deethylase (EROD) activity, which measures CYP1A1 and CYP1B1 together, correlated with BPdG, but NQO1 activity did not. Despite more numerous levels of CYP1B1 and NQO1 RNA cpn in unexposed and BP-exposed NHMECs and MCF-7cells, BPdG formation was only correlated with induction of CYP1A1 RNA cpn. The higher level of BPdG in MCF-7 cells, compared to NHMECs, may have been due to a much increased induction of CYP1A1 and EROD. Overall, BPdG correlation was observed with CYP1A1 protein and CYP1A1/1B1 enzyme activity, but not with CYP1B1 or NQO

  15. Phenotype refinement strengthens the association of AHR and CYP1A1 genotype with caffeine consumption.

    PubMed

    McMahon, George; Taylor, Amy E; Davey Smith, George; Munafò, Marcus R

    2014-01-01

    Two genetic loci, one in the cytochrome P450 1A1 (CYP1A1) and 1A2 (CYP1A2) gene region (rs2472297) and one near the aryl-hydrocarbon receptor (AHR) gene (rs6968865), have been associated with habitual caffeine consumption. We sought to establish whether a more refined and comprehensive assessment of caffeine consumption would provide stronger evidence of association, and whether a combined allelic score comprising these two variants would further strengthen the association. We used data from between 4,460 and 7,520 women in the Avon Longitudinal Study of Parents and Children, a longitudinal birth cohort based in the United Kingdom. Self-report data on coffee, tea and cola consumption (including consumption of decaffeinated drinks) were available at multiple time points. Both genotypes were individually associated with total caffeine consumption, and with coffee and tea consumption. There was no association with cola consumption, possibly due to low levels of consumption in this sample. There was also no association with measures of decaffeinated drink consumption, indicating that the observed association is most likely mediated via caffeine. The association was strengthened when a combined allelic score was used, accounting for up to 1.28% of phenotypic variance. This was not associated with potential confounders of observational association. A combined allelic score accounts for sufficient phenotypic variance in caffeine consumption that this may be useful in Mendelian randomization studies. Future studies may therefore be able to use this combined allelic score to explore causal effects of habitual caffeine consumption on health outcomes.

  16. Catalytic and Immunochemical Detection of Hepatic and Extrahepatic Microsomal Cytochrome P450 1A1 (CYP1A1) in White-sided Dolphin (Lagenorhynchus acutus)

    PubMed Central

    Wilson, Joanna Y.; Moore, Michael J.; Stegeman, John J.

    2009-01-01

    a major site of CYP1A1 expression and probably of biotransformation of CYP1A substrates in white-sided dolphin. The expression of an EROD catalyst in liver likely reflects induction by PCBs, but the P450 enzyme catalyzing hepatic EROD activity in these whales may not be CYP1A1. PMID:20005581

  17. Risk of renal cell carcinoma and polymorphism in phase I xenobiotic metabolizing CYP1A1 and CYP2D6 enzymes.

    PubMed

    Ahmad, Shiekh Tanveer; Arjumand, Wani; Seth, Amlesh; Nafees, Sana; Rashid, Summya; Ali, Nemat; Hamiza, Oday O; Sultana, Sarwat

    2013-10-01

    The progressive increase in sporadic renal cell carcinoma (RCC) observed in industrialized countries supports the opinion that certain carcinogens present in the environment (tobacco smoke, drugs, pollutants, and dietary constituents) may affect the occurrence and progression of this disease in developing countries like India. The polymorphism of the enzymes involved in metabolism of such environmental factors may, therefore, confer variable propensity to RCC. The possible association between RCC and a polymorphism of the CYP1A1 and CYP2D6 genes specific to the Indian population was examined using peripheral blood DNA from 196 RCC cases and 250 population controls with detailed data of clinicopathologic characteristics for the disease. The CYP1A1 (val) "variant" genotype, which contains at least 1 copy of the CYP1A1 variant alleles, was found to be associated with a 2.03-fold [GG ver. AA/AG, unadjusted OR = 2.03; 95%CI = 1.233-3.342; P = 0.005] increase in the risk of RCC. There was also a significant association (p(trend) = 0.034) between higher frequency of RCC subjects containing at least of copy of the CYP1A1 (val) "variant" genotype with III or IV Fuhrman's grade. Whereas, the CYP2D6 polymorphism did not show any association with RCC risk [TT ver. CT/CC, unadjusted OR = 95%CI = 1.233-3.342; P = 0.005]. There was a significant association (p(trend) = 0.001) between the poor metabolizer CYP2D6 (TT) and progression towards higher pathological stage of RCC. Our data demonstrate for the first time a significant association between pharmacogenetic polymorphisms of CYP1A1 and risk of RCC development in the Indian population. The findings suggest that inter-individual variation in the phase I metabolic enzymes involved in the fictionalization and detoxification of specific xenobiotics is an important susceptibility factor for development and progression of RCC in Indians.

  18. Carnosol, a Constituent of Zyflamend, Inhibits Aryl Hydrocarbon Receptor-Mediated Activation of CYP1A1 and CYP1B1 Transcription and Mutagenesis

    PubMed Central

    Mohebati, Arash; Guttenplan, Joseph B.; Kochhar, Amit; Zhao, Zhong-Lin; Kosinska, Wieslawa; Subbaramaiah, Kotha; Dannenberg, Andrew J.

    2012-01-01

    The aryl hydrocarbon receptor (AhR), a ligand-activated member of the basic-helix-loop-helix family of transcription factors, plays a significant role in polycyclic aromatic hydrocarbon (PAH) induced carcinogenesis. In the upper aerodigestive tract of humans, tobacco smoke, a source of PAHs, activates the AhR leading to increased expression of CYP1A1 and CYP1B1, which encode proteins that convert PAHs to genotoxic metabolites. Inhibitors of Hsp90 ATPase cause a rapid decrease in levels of AhR, an Hsp90 client protein, and thereby block PAH-mediated induction of CYP1A1 and CYP1B1. The main objective of this study was to determine whether Zyflamend, a polyherbal preparation, suppressed PAH-mediated induction of CYP1A1 and CYP1B1 and inhibited DNA adduct formation and mutagenesis. We also investigated whether carnosol, one of multiple phenolic antioxidants in Zyflamend, had similar inhibitory effects. Treatment of cell lines derived from oral leukoplakia (MSK-Leuk1) and skin (HaCaT) with benzo[a]pyrene (B[a]P), a prototypic PAH, induced CYP1A1 and CYP1B1 transcription, resulting in enhanced levels of message and protein. Both Zyflamend and carnosol suppressed these effects of B[a]P. Notably, both Zyflamend and carnosol inhibited Hsp90 ATPase activity and caused a rapid reduction in AhR levels. The formation of B[a]P induced DNA adducts and mutagenesis were also inhibited by Zyflamend and carnosol. Collectively, these results show that Zyflamend and carnosol inhibit Hsp90 ATPase leading to reduced levels of AhR, suppression of B[a]P-mediated induction of CYP1A1 and CYP1B1 and inhibition of mutagenesis. Carnosol-mediated inhibition of Hsp90 ATPase activity can help explain the chemopreventive activity of herbs such as Rosemary, which contain this phenolic antioxidant. PMID:22374940

  19. CYP1A1 genetic polymorphisms and uterine leiomyoma risk: a meta-analysis

    PubMed Central

    Wang, Fen; Chen, Jiying; Wang, Lin; Ma, Yulan; Mayinuer, Niyazi

    2015-01-01

    Background: Some studies assessed the association between CYP1A1 MspI and Ile462Val polymorphisms and uterine leiomyoma (UL) risk. However, the results were controversial. We did this meta-analysis to determine the association between CYP1A1 MspI and Ile462Val polymorphisms and UL risk. Materials and methods: We searched databases containing PubMed, Springer Link, EMBASE, Chinese National Knowledge Infrastructure (CNKI) up to 11 October 2014. Pooled ORs and 95% CIs were used to assess the strength of the associations. Results: In total, 9 case-control studies with 2157 UL cases and 2197 healthy controls were included in this meta-analysis. CYP1A1 Ile462Val polymorphism was significantly associated with UL risk (OR = 2.29, 95% CI 1.75-2.99, P < 0.00001). In the subgroup analysis by race, significantly increased risks were found in the Asians (OR = 2.76, 95% CI 1.86-4.09, P < 0.00001) and Caucasians (OR = 1.87, 95% CI 1.30-2.68, P = 0.0007). However, MspI polymorphism was not significantly associated with UL risk (OR = 1.15, 95% CI 0.90-1.47, P = 0.27). In the subgroup analysis by race, no significant association was found in the Asians (OR = 1.15, 95% CI 0.86-1.54, P = 0.35). Conclusion: In summary, the results of the meta-analysis suggested that CYP1A1 Ile462Val polymorphism was significantly associated with UL risk. PMID:26064254

  20. GSTM1 and CYP1A1 polymorphisms, tobacco, air pollution, and lung cancer: a study in rural Thailand

    SciTech Connect

    Pisani, P.; Srivatanakul, P.; Randerson-Moor, J.; Vipasrinimit, S.; Lalitwongsa, S.; Unpunyo, P.; Bashir, S.; Bishop, D.T.

    2006-04-15

    Incidence rates of lung cancer is high in Lampang Province in northern Thailand, particularly in women. This study was conducted to quantify the risk of lung cancer associated with exposures prevalent in the area and to investigate possible interactions with genetic susceptibility. The presence of several large open-cast coal mines from 1955 close to electricity-generating plants was a particular focus of concern. A point source air pollution exposure index was calculated for each village/ township reported in residential histories based on the linear distance from the Mae Moh Center (the area of the electricity-generating plants), the year-specific gaseous (SO{sub 2} and NO{sub 2}) or total suspended particulate emissions from the Mae Moh Power Plant, and the percentage of wind from the center. Odds ratios for the disease associated with categorical variables were estimated within unconditional logistic regression. Extraction of genomic DNA and genotyping of variants in CYP1A1 and GSTM1 were conducted to assess the extent of modification of risk by these genes that are involved in the metabolism of polycyclic aromatic hydrocarbons. Smoking of local high tar unfiltered products is commonamongst women. None of the three polymorphisms examined increased the risk of lung cancer or modified the risk associated with smoking. 96% of male and 64% of female lung cancer incidence were explained by tobacco smoking. None of the potential sources of air pollution deriving from the combustion of coal and wood, or polymorphisms in the CYP1A1 gene or deletion of the GSTM1 had an effect on the risk of lung cancer, either together or separately.

  1. CYP1A1 Ile462Val and GSTT1 modify the effect of cord blood cotinine on neurodevelopment at 2 years of age.

    PubMed

    Hsieh, Chia-Jung; Liao, Hua-Fang; Wu, Kuen-Yuh; Hsieh, Wu-Shiun; Su, Yi-Ning; Jeng, Suh-Fang; Yu, Shih-Ni; Chen, Pau-Chung

    2008-09-01

    Maternal exposure to environmental tobacco smoke (ETS) has been reported to be associated with children's neurobehavioral development but there was no studies investigating the genetic susceptibilities to maternal ETS exposure on children's neurodevelopment. The aim of the study was to explore the modification effect of metabolic gene polymorphisms to cord blood cotinine on children's neurodevelopment at the 2 years of age. This study is one investigation of the Taiwan Birth Panel Study and a total of 145 pregnant women and their neonates were recruited between April 2004 and January 2005. We interviewed them by a structured questionnaire after delivery and collected umbilical cord blood at birth. Cotinine in umbilical cord blood as an indicator of environmental tobacco smoke was analyzed by using HPLC-MS/MS and the detection limited of this method was 0.05ng/mL. Four metabolic genes, CYP1A1 MspI, CYP1A1 Ile462Val, GSTT1 and GSTM1 were identified. The Comprehensive Developmental Inventory for Infants and Toddlers (CDIIT) was used for assessing children's neurodevelopment at the 2 years of age accompanying with the measurement of Home Observation for Measurement of the Environment scale. We used multiple linear regression models to estimate the effects of cord blood cotinine and gene modification. Cotinine levels were significantly negatively associated with developmental quotients (DQs) of the whole test, and cognitive, language, fine-motor and social subtests of the CDIIT. Lower cognitive and language DQs were found in exposed group with absent type of GSTT1. In addition, the lowest scores in fine-motor and whole test DQs were detected in exposed group with CYP1A1 Ile462Val variant type and GSTT1 absent type. It can be concluded that CYP1A1 Ile462Val and GSTT1 metabolic genes can modify the effect of cord blood cotinine on early child neurodevelopment especially for language and fine motor development.

  2. Up-regulation of hepatic ABCC2, ABCG2, CYP1A1 and GST in multixenobiotic-resistant killifish (Fundulus heteroclitus) from the Sydney Tar Ponds, Nova Scotia, Canada.

    PubMed

    Paetzold, S Christine; Ross, Neil W; Richards, Robert C; Jones, Martha; Hellou, Jocelyne; Bard, Shannon M

    2009-07-01

    Cellular defence against accumulation of toxic xenobiotics includes metabolism by phase I and II enzymes and export of toxicants and their metabolites via ATP-binding cassette (ABC) transporters. Liver gene expression of representatives of these three protein groups was examined in a population of multixenobiotic-resistant killifish (Fundulus heteroclitus) from the Sydney Tar Ponds, Nova Scotia, Canada. The Tar Ponds are heavily polluted with polycyclic aromatic hydrocarbons, polychlorinated biphenyls and heavy metals. The relationship among ABC transporters ABCB1, ABCB11, ABCC2, ABCG2, phase I enzyme cytochrome P4501A1 (CYP1A1) and phase II enzyme glutathione-S-transferase (GST-mu) was investigated by quantifying hepatic transcript abundance. In Tar Pond killifish, hepatic mRNA expression levels of ABCC2, ABCG2, CYP1A1 and GST-mu were elevated compared to reference sites, suggesting that hydrophobic contaminants undergo phase I and II metabolism and are then excreted into the bile of these fish. Hepatic ABCB1 and ABCB11 mRNA were not up-regulated in Tar Pond fish compared to two reference sites, indicating that these two proteins are not involved in conferring multixenobiotic resistance to Tar Pond killifish. The results suggest instead that liver up-regulation of phase I and II enzymes and complementary ABC transporters ABCC2 and ABCG2 may confer contaminant resistance to Tar Pond fish.

  3. Caged and wild fish: Induction of hepatic cytochrome P-450 (CYP1A1) as an environmental biomonitor

    SciTech Connect

    Haasch, M.L.; Lech, J.J. ); Prince, R.; Cooper, K.R. ); Wejksnora, P.J. )

    1993-05-01

    Hepatic monooxygenase activity can be induced by many different environmental chemical contaminants, and measurement of this activity has been proposed as an environmental biomonitor. Using in situ caged catfish and largemouth bass, and collected wild killifish, environmental induction of hepatic CYP1A1 was investigated using catalytic enzyme assays, regiospecific metabolism, immunodetection, and nucleic acid hybridization. The purpose of these studies was to evaluate these techniques for detection of CYP1A1 induction as a potential environmental biomonitor of environmental chemical contamination. Exposure of catfish in cages to polyaromatic hydrocarbon- (PAH-) and polychlorinated biphenyl- (PCB-) contaminated river water for two, four, or six weeks resulted in fourfold increases in ethoxyresorufin-O-deethylase (EROD) activity and three- and fivefold increases in immunoreactive CYP1A1 protein and hybridizable CYP1A1 mRNA, respectively, when compared to laboratory water control values. Hybridizable CYP1A1 mRNA in caged largemouth bass increased 5.1-fold at 1 d of exposure. Caged largemouth bass had 5-, 1.4-, and 0.8-fold increases at 3 d and 6-, 2.4-, 0.4-fold increases at 7 d of river water exposure in EROD, immunoreactive CYP1A1 protein, and CYP1A1 mRNA, respectively, when compared to laboratory water control values. Liver of killifish from a 2,3,7,8-tetrachlorodibenzo-p-dioxin-contaminated area had threefold higher EROD activity and similarly elevated immunoreactive CYP1A1 protein, a two- to fourfold increase in CYP1A1 mRNA, and a four- to eightfold increase in 6[beta]-hydroxyprogesterone activity, when compared to killifish livers sampled from a clean site.

  4. Dioxin induces Ahr-dependent robust DNA demethylation of the Cyp1a1 promoter via Tdg in the mouse liver

    NASA Astrophysics Data System (ADS)

    Amenya, Hesbon Z.; Tohyama, Chiharu; Ohsako, Seiichiroh

    2016-10-01

    The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1). A single dose of TCDD administered to adult mice induced Ahr-dependent CpG hypomethylation, changes in histone modifications, and thymine DNA glycosylase (Tdg) recruitment at the Cyp1a1 promoter in the liver within 24 hrs. These epigenetic changes persisted until 40 days post-TCDD treatment and there was Cyp1a1 mRNA hyperinduction upon repeat administration of TCDD at this time-point. Our demethylation assay using siRNA knockdown and an in vitro methylated plasmid showed that Ahr, Tdg, and the ten-eleven translocation methyldioxygenases Tet2 and Tet3 are required for the TCDD-induced DNA demethylation. These results provide novel evidence of Ahr-driven active DNA demethylation and epigenetic memory. The epigenetic alterations influence response to subsequent chemical exposure and imply an adaptive mechanism to xenobiotic stress.

  5. Dioxin induces Ahr-dependent robust DNA demethylation of the Cyp1a1 promoter via Tdg in the mouse liver

    PubMed Central

    Amenya, Hesbon Z.; Tohyama, Chiharu; Ohsako, Seiichiroh

    2016-01-01

    The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1). A single dose of TCDD administered to adult mice induced Ahr-dependent CpG hypomethylation, changes in histone modifications, and thymine DNA glycosylase (Tdg) recruitment at the Cyp1a1 promoter in the liver within 24 hrs. These epigenetic changes persisted until 40 days post-TCDD treatment and there was Cyp1a1 mRNA hyperinduction upon repeat administration of TCDD at this time-point. Our demethylation assay using siRNA knockdown and an in vitro methylated plasmid showed that Ahr, Tdg, and the ten-eleven translocation methyldioxygenases Tet2 and Tet3 are required for the TCDD-induced DNA demethylation. These results provide novel evidence of Ahr-driven active DNA demethylation and epigenetic memory. The epigenetic alterations influence response to subsequent chemical exposure and imply an adaptive mechanism to xenobiotic stress. PMID:27713569

  6. CYP1B1, CYP1A1, MPO, and GSTP1 polymorphisms and lung cancer risk in never-smoking Korean women.

    PubMed

    Yoon, Kyong-Ah; Kim, Jin Hee; Gil, Hyea-Jin; Hwang, Hyukkee; Hwangbo, Bin; Lee, Jin Soo

    2008-04-01

    Polymorphisms in metabolic genes encoding phase I and phase II enzymes are thought to modulate the risk of lung cancer via changes in enzymatic activity. Recently, the effect of these metabolic enzymes and their interaction with environmental factors has been studied in both smokers and also never-smokers, since never-smokers are a good model in which to study genetic susceptibility at low-dose carcinogen exposure. Here, we investigated the association of CYP1A1 Ile462Val, CYP1B1 Leu432Val, GSTP1 Ile105Val, MPO G-463A polymorphisms and lung cancer risk in never-smoking Korean women. In this case-control study of 213 lung cancer patients and 213 age-matched healthy controls, we found that carrying one variant allele of the CYP1A1 Ile462Val polymorphism was associated with a significantly decreased risk of lung adenocarcinoma (adjusted odds ratio (OR)=0.63; 95% confidence interval (CI), 0.41-0.99). Furthermore, the combination of risk genotypes of CYP1B1 Leu432Val with CYP1A1 Ile462Val was associated with the risk of lung adenocarcinoma (adjusted OR=2.16; 95% CI, 1.02-4.57) as well as overall lung cancer (adjusted OR=2.23; 95% CI 1.01-4.89). The polymorphisms of GSTP1 Ile105Val and MPO G-463A showed no significant association with lung cancer. Theses results suggest that the CYP1A1 Ile462Val polymorphism is associated with a reduced risk of lung adenocarcinoma in never-smoking Korean women, whereas specific combinations of variant genotypes for metabolic enzymes increase lung cancer risk considerably.

  7. CYP1A1 MspI polymorphism and the risk of oral squamous cell carcinoma: Evidence from a meta-analysis

    PubMed Central

    XIE, SHANG; LUO, CHONGDAI; SHAN, XIAOFENG; ZHAO, SHUSHAN; HE, JING; CAI, ZHIGANG

    2016-01-01

    Numerous case-control studies have investigated whether the CYP1A1 gene polymorphism is involved in the occurrence of oral squamous cell carcinoma (OSCC); however, the conclusions are inconsistent. In order to further explore the correlation and obtain a strong conclusion, a meta-analysis was performed to systematically assess the association between the CYP1A1 MspI polymorphism and risk of OSCC. In the present meta-analysis, the odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were used to assess the association. The statistical analyses were performed with STATA 11.0 software. The heterogeneity was assessed by Q test and I2test. The final analysis included 10 studies of 1,505 cases and 1,967 controls. The overall results suggested that the CYP1A1 MspI polymorphism was significantly associated with an increased risk of OSCC (CC+TC vs. TT: OR, 1.31; 95% CI, 1.01–1.70; P=0.043; CC vs. TC+TT: OR, 2.38; 95% CI, 1.58–3.58; P<0.001; CC vs. TT: OR, 2.52; 95% CI, 1.60–3.96; P<0.001; and C vs. T: OR, 1.45; 95% CI, 1.15–1.83; P<0.001). In a stratified analysis by ethnicity, a statistically significant correlation existed in the Asian population, but not mixed-race and Caucasian populations. In conclusion, despite several limitations, the present meta-analysis established that the CYP1A1 MspI polymorphism may be a risk factor for OSCC, particularly among the Asian population. PMID:27073686

  8. CYP1A1 MspI polymorphism and susceptibility to lung cancer in the Chinese population: an updated meta-analysis and review

    PubMed Central

    Wang, Xin; Yue, Kai; Hao, Li-Ran

    2015-01-01

    Background: Although many epidemiologic studies have investigated the CYP1A1 MspI gene polymorphisms and their associations with lung cancer (LC), definite conclusions cannot be drawn. Objective: To clarify the effects of CYP1A1 MspI polymorphisms on the risk of LC, an update meta-analysis was performed in only Chinese population. Methods: Related studies were identified from PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) till October 2014. Pooled ORs and 95% CIs were used to assess the strength of the associations. Results: A total of 22 studies including 3016 LC cases and 3932 controls were involved in this meta-analysis. Overall, significant association was found between CYP1A1 MspI polymorphism and LC risk when all studies in the Chinese population pooled into this meta-analysis (CC vs. TT: OR = 1.42, 95% CI = 1.11-1.80; CT + CC vs. TT: OR = 1.26, 95% CI = 1.06–1.50; CC vs. CT + TT: OR = 1.30, 95% CI = 1.04-1.61; C vs. T: OR = 1.21, 95% CI = 1.07-1.37). In subgroup analyses stratified by ethnicity and source of controls, significantly increased risk was found in Chinese Han people and in population-based studies. Conclusions: This meta-analysis provides the evidence that CYP1A1 MspI polymorphism may contribute to the LC development in the Chinese population and studies with large sample size and wider spectrum of population are warranted to verify this finding. PMID:26550103

  9. Association of CYP1A1 and CYP1B1 polymorphisms with bone mineral density variations in postmenopausal Mexican-Mestizo women.

    PubMed

    Chávez, Bertha; Vilchis, Felipe; Rojano-Mejía, David; Coral Vázquez, Ramón Mauricio; Aguirre-García, María Del Carmen; Canto, Patricia

    2017-03-16

    Herein, we investigated potential associations between polymorphisms of genes related to estrogen metabolism and bone mineral density (BMD) in postmenopausal women. This was a cross-sectional study, in which two hundred and ninety postmenopausal Mexican-Mestizo women were studied. The BMD of the lumbar spine (LS), total hip (TH), and femoral neck (FN) was measured. The distribution of the genetic polymorphisms, including rs1799814 and rs1048943 at CYP1A1 as well as rs1056836 at CYP1B1, were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), single-stranded conformational polymorphism (SSCP), and DNA sequencing. Deviations from Hardy-Weinberg equilibrium (HWE) were tested, and linkage disequilibrium (LD) was calculated by direct correlation (r(2)). Moreover, haplotype analysis was performed. All polymorphisms were in HWE. The genotype and allele distributions of the three single nucleotide polymorphisms (SNPs) studied showed no significant differences. However, statistical significance was reached when constructing haplotypes. The CG haplotype in CYP1A1 was associated with variations in LS and FN BMD after adjustment for covariates (p = 0.021 and 0.045, respectively), but the association with TH BMD was not significant. These results suggested that the CG haplotype in CYP1A1 may play an important role in the mechanism of osteoporosis and may be useful as a genetic marker.

  10. Role of CYP1A1 in the biological activity of methylated resveratrol analogue, 3,4,5,4'-tetramethoxystilbene (DMU-212) in ovarian cancer A-2780 and non-cancerous HOSE cells.

    PubMed

    Piotrowska-Kempisty, Hanna; Klupczyńska, Agnieszka; Trzybulska, Dorota; Kulcenty, Katarzyna; Sulej-Suchomska, Anna Maria; Kucińska, Małgorzata; Mikstacka, Renata; Wierzchowski, Marcin; Murias, Marek; Baer-Dubowska, Wanda; Kokot, Zenon; Jodynis-Liebert, Jadwiga

    2017-02-05

    The role of CYP1A1 and CYP1B1 enzymes in the biotransformation and biological activity of the methylated resveratrol analogue, 3,4,5,4'-tetramethoxystilbene (DMU-212) is still elusive. Our recently published data have shown that one of the metabolites of DMU-212, 3'-hydroxy-3,4,5,4'-tetramethoxystilbene (DMU-214) exerts more potent cytotoxic effects in A-2780 ovarian cancer cell line, as compared to the parent compound. Hence, this study aims to elucidate whether the biological activity of DMU-212 is related to its biotransformation to DMU-214. Furthermore, we aimed to assess which enzymes of CYP1 family are involved in the biotransformation of DMU-212. The human ovarian cancer cell lines A-2780, A-2780CYP1A1(-) and non-cancerous human ovarian surface epithelial (HOSE) cells were employed in the present study. In contrary to other authors' suggestions we have found that CYP1A1 is the major enzyme of CYP1 family involved in the metabolic activation of DMU-212. Since the distinctly weaker anti-proliferative effects of DMU-212 against HOSE and A-2780CYP1A1(-) cells have been associated with the lack of the expression of CYP1A1, we suggest that the biological activity of the parent compound may be related to its metabolic activation to DMU-214 and the level of this enzyme.

  11. Soy isoflavones, CYP1A1, CYP1B1, and COMT polymorphisms, and breast cancer: a case-control study in southwestern China.

    PubMed

    Wang, Qiong; Li, Hui; Tao, Ping; Wang, Yuan-Ping; Yuan, Ping; Yang, Chun-Xia; Li, Jia-Yuan; Yang, Fei; Lee, Hui; Huang, Yuan

    2011-08-01

    CYP1A1, CYP1B1, and COMT are key enzymes involved in estrogen metabolism. Soy isoflavones, phytoestrogens found in soy foods, may modify the activity of these enzymes. A case-control study was conducted to assess the associations between soy isoflavone intake and the CYP1A1 Ile462Val, CYP1B1 Val432Leu, and COMT Val158Met polymorphisms and breast cancer, as well as their combined effects on breast cancer. A total of 400 newly diagnosed breast cancer cases and 400 healthy controls were recruited. Participants' daily intake of soy isoflavones (DISI [mg/day]) was calculated and transformed to energy-adjusted DISI by the residual method. Gene sequencing was used to analyze CYP1A1, CYP1B1, and COMT polymorphisms. Adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) were estimated by conditional logistic regression. A strong protective dose-dependent effect of energy-adjusted DISI on breast cancer was found in both pre- and postmenopausal women (P(trend) < 0.05). Among all women and in the postmenopausal subgroup, COMT Met/Met and CYP1B1 Leu/Leu susceptible genotype carriers had higher risk of breast cancer (aORs > 1, OR 95% CIs exclude 1). In premenopausal women, only carrying CYP1B1 Leu/Leu was associated with breast cancer risk (aOR = 2.05, 95% CI: 1.11-3.79). Carrying CYP1A1 Val/Val was related to breast cancer risk only among all women. A stratified analysis was performed at two levels of energy-adjusted DISI, with wildtype homozygous genotypes and low energy-adjusted DISI as the reference. In the high energy-adjusted DISI subgroup, carrying the CYP1B1 Leu/Leu genotype did not affect breast cancer risk in either all women or in the menopausal subgroups, compared with the reference. Overall, in Han Chinese women, carrying CYP1A1 Val/Val and COMT Met/Met appears to be associated with breast cancer risk, especially in postmenopausal women. CYP1B1 susceptible genotypes (Val/Leu or Leu/Leu) also contribute to increased breast cancer risk

  12. Polycyclic aromatic hydrocarbon-DNA adducts and the CYP1A1 restriction fragment length polymorphism

    SciTech Connect

    Shields, P.G.; Bowman, E.D.; Weston, A.; Harris, C.C.; Sugimura, H.; Caporaso, N.E.; Petruzzelli, S.F. ); Trump, B.F. )

    1992-11-01

    Human cancer risk assessment at a genetic level involves the investigation of carcinogen metabolism and DNA adduct formation. Wide interindividual differences in metabolism result in different DNA adduct levels. For this and other reasons, many laboratories have considered DNA adducts to be a measure of the biologically effective dose of a carcinogen. Techniques for studying DNA adducts using chemically specific assays are becoming available. A modification of the [sup 32]P-postlabeling assay for polycyclic aromatic hydrocarbon DNA adducts described here provides potential improvements in quantification. DNA adducts, however, reflect only recent exposure to carcinogens; in contrast, genetic testing for metabolic capacity indicates the extent to which carcinogens can be activated and exert genotoxic effects. Such studies may reflect both separate and integrated risk factors together with DNA adduct levels. A recently described restriction fragment length polymorphism for the CYP1A1, which codes for the cytochrome P450 enzyme primarily responsible for the metabolic activation of carcinogenic polycyclic aromatic hydrocarbons, has been found to be associated with lung cancer risk in a Japanese population. In a subset of individuals enrolled in a US lung cancer case-control study, no association with lung cancer was found. 17 refs., 3 figs.

  13. The interaction between smoking and CYP1A1 MspI polymorphism on lung cancer: a meta-analysis in the Chinese population.

    PubMed

    Zhang, L-P; Wang, C-P; Li, L-H; Tang, Y-F; Li, W-C

    2016-02-26

    Many studies have examined the interaction between CYP1A1 MspI gene polymorphism and smoking for the risk of lung cancer risk in Chinese, but their results have been inconsistent. Therefore, a meta-analysis was performed to ascertain this issue. PubMed, Springer Link, Ovid and other Chinese databases were searched to include all the relevant studies. Smoking status was categorised as 'smokers' and 'non-smokers.' The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using fixed or random effect model. Subgroup analyses according to ethnicity, source of control and geographical location were also conducted. This meta-analysis identified 13 studies containing 2248 lung cases and 3079 controls. Overall, a significant association between lung cancer and the variants of CYP1A1 MspI was found among smokers (type B and type C combined vs. type A: OR = 1.89, 95% CI = 1.15-3.11, P = 0.000 for heterogeneity), whereas not found among non-smokers. Similar to the overall results, stratified analyses showed that the increased risk of lung cancer was observed in population-based studies and north China among smokers (OR = 1.65, 95%CI = 1.03-2.66; OR = 2.00, 95% CI = 1.14-3.53). Our meta-analysis showed that there was an interaction between the CYP1A1 MspI and smoking on the risk of lung cancer in the Chinese population.

  14. Primary DNA damage and genetic polymorphisms for CYP1A1, EPHX and GSTM1 in workers at a graphite electrode manufacturing plant

    PubMed Central

    Moretti, Massimo; Dell'Omo, Marco; Villarini, Milena; Pastorelli, Roberta; Muzi, Giacomo; Airoldi, Luisa; Pasquini, Rossana

    2007-01-01

    Background The results of a cross-sectional study aimed to evaluate whether genetic polymorphisms (biomarkers of susceptibility) for CYP1A1, EPHX and GSTM1 genes that affect polycyclic aromatic hydrocarbons (PAH) activation and detoxification might influence the extent of primary DNA damage (biomarker of biologically effective dose) in PAH exposed workers are presented. PAH-exposure of the study populations was assessed by determining the concentration of 1-hydroxypyrene (1OHP) in urine samples (biomarker of exposure dose). Methods The exposed group consisted of workers (n = 109) at a graphite electrode manufacturing plant, occupationally exposed to PAH. Urinary 1OHP was measured by HPLC. Primary DNA damage was evaluated by the alkaline comet assay in peripheral blood leukocytes. Genetic polymorphisms for CYP1A1, EPHX and GSTM1 were determined by PCR or PCR/RFLP analysis. Results 1OHP and primary DNA damage were significantly higher in electrode workers compared to reference subjects. Moreover, categorization of subjects as normal or outlier highlighted an increased genotoxic risk OR = 2.59 (CI95% 1.32–5.05) associated to exposure to PAH. Polymorphisms in EPHX exons 3 and 4 was associated to higher urinary concentrations of 1OHP, whereas none of the genotypes analyzed (CYP1A1, EPHX, and GSTM1) had any significant influence on primary DNA damage as evaluated by the comet assay. Conclusion The outcomes of the present study show that molecular epidemiology approaches (i.e. cross-sectional studies of genotoxicity biomarkers) can play a role in identifying common genetic risk factors, also attempting to associate the effects with measured exposure data. Moreover, categorization of subjects as normal or outlier allowed the evaluation of the association between occupational exposure to PAH and DNA damage highlighting an increased genotoxic risk. PMID:17908297

  15. Competitive inhibition of carcinogen-activating CYP1A1 and CYP1B1 enzymes by a standardized complex mixture of PAH extracted from coal tar

    SciTech Connect

    Mahadevan, B.; Marston, C.P.; Luch, A.; Dashwood, W.M.; Brooks, E.; Pereira, C.; Doehmer, J.; Baird, W.M.

    2007-03-15

    A complex mixture of polycyclic aromatic hydrocarbons (PAH) extracted from coal tar, the Standard Reference Material (SRM) 1597, was recently shown to decrease the levels of DNA binding of the 2 strong carcinogens benzo(a)pyrene (BP) and dibenzo(a,l)pyrene (DBP) in the human mammary carcinoma-derived cell line MCF-7. The present study was designed to further elucidate the biochemical mechanisms involved in this inhibition process. We examined the effects of SRM 1597 on the metabolic activation of BP and DBP toward DNA-binding derivatives in Chinese hamster cells expressing either human cytochrome P450 (CYP) 1A1 or CYP1B1. The data obtained from biochemical experiments revealed that SRM 1597 competitively inhibited the activity of both human enzymes as analyzed by 7-ethoxyresorufin O-deethylation assays. While the Michaelis-Menten constant (K-M) was {lt} 0.4 {mu}M in the absence of SRM 1597, this value increased up to 1.12 (CYP1A1) or 4.45 {mu}M (CYP1B1) in the presence of 0.1 {mu} g/ml SRM 1597. Hence the inhibitory effects of the complex mixture on human CYP1B1 were much stronger when compared to human CYP1A1 Taken together, the decreases in PAH-DNA adduct formation on co-treatment with SRM 1597 revealed inhibitory effects on the CYP enzymes that convert carcinogenic PAH into DNA-binding metabolites. The implications for the tumorigenicity of complex environmental PAR mixtures are discussed.

  16. CYP1A1 MspI polymorphism and acute myeloid leukemia risk: meta-analyses based on 5018 subjects

    PubMed Central

    2012-01-01

    Background Evidence indicates that CYP1A1 MspI polymorphism might be a possible risk factor for several malignancies. A growing body of literature has been devoted to the association of CYP1A1 MspI polymorphism with acute myeloid leukemia (AML). However, the results remain conflicting. The aim of the present study was to derive a more precise estimation of the relationship. Methods Meta-analyses assessing the association of CYP1A1 MspI variation with AML were conducted and subgroup analyses on ethnicity and age groups were further performed. Eligible studies were identified for the period up to May 2012. Results A total of ten case–control studies including 1330 cases and 3688 controls were selected for analysis. The overall data failed to indicate a significant association of CYP1A1 MspI polymorphism with AML risk (C vs T: OR = 1.13; 95%CI = 0.87-1.48; CC vs TT: OR = 1.72; 95%CI = 0.99-3.01; CC + TC vs TT: OR = 1.16; 95%CI = 0.86-1.55). In subgroup analysis stratified by ethnicity, significant AML risk was shown among Asians (CC + TC vs TT: OR = 1.33; 95%CI = 1.09-1.62) but not Caucasians or mixed races. In subgroup analysis regarding age groups, no associations were observed in either the childhood AML or the adult AML subgroups. Conclusion The results of the present study suggested that CYP1A1 MspI polymorphism might be a risk factor for AML among Asians. Further investigations are needed to confirm the conclusions. PMID:22846179

  17. Xenobiotic Metabolizing Enzyme and Transporter Gene Expression in Primary Cultures of Human Hepatocytes Modulated by ToxCast Chemicals

    EPA Science Inventory

    ToxCast chemicals were assessed for induction or suppression of xenobiotic metabolizing enzyme and transporter gene expression using primary human hepatocytes. The mRNA levels of 14 target and 2 control genes were measured: ABCB1, ABCB11, ABCG2, SLCO1B1, CYP1A1, CYP1A2, CYP2B6, C...

  18. Modulation of Xenobiotic Metabolizing Enzyme and Transporter Gene Expression in Primary Cultures of Human Hepatocytes by ToxCast Chemicals

    EPA Science Inventory

    ToxCast chemicals were assessed for induction or suppression of xenobiotic metabolizing enzyme and transporter gene expression using primary human hepatocytes. The mRNA levels of 14 target and 2 control genes were measured: ABCB1, ABCB11, ABCG2, SLCO1B1, CYP1A1, CYP1A2, CYP2B6, C...

  19. CYP1A1 and CYP1B1 genetic polymorphisms and uterine leiomyoma risk in Chinese women

    PubMed Central

    Ye, Yi; Cheng, Xiao; Luo, Hai-Bo; Liu, Li; Li, Ying-Bi

    2008-01-01

    Purpose The aim of the study was to evaluate the association of CYP1A1 and CYP1B1 polymorphisms with uterine leiomyoma in Chinese women. Methods We investigated 100 women with clinically diagnosed uterine leiomyoma and 110 healthy normal subjects from Chinese women. The genetic distribution of two CYP1A1 polymorphisms at MspI, Ile462Val and four CYP1B1 polymorphisms at Arg48Gly, Ala119Ser, Leu432Val, Asp449Asp were analyzed by polymerase chain reaction–restriction fragment length polymorphism and DNA sequencing method. Results All the SNPs showed polymorphisms in Chinese women. The genotype A/G and the allele G on Ile462Val was significantly different between uterine leiomyoma patients and controls (P < 0.05). Conclusion These results suggest that the genotype of CYP1A1 Ile462Val was associated with the increased risk of uterine leiomyomas in Chinese women. PMID:18763031

  20. CYP1A1 (Ile462Val), CYP1B1 (Ala119Ser and Val432Leu), GSTM1 (null), and GSTT1 (null) polymorphisms and bladder cancer risk in a Turkish population.

    PubMed

    Berber, Ufuk; Yilmaz, Ismail; Yilmaz, Omer; Haholu, Aptullah; Kucukodaci, Zafer; Ates, Ferhat; Demirel, Dilaver

    2013-01-01

    We aimed to investigate bladder cancer risk with reference to polymorphic variants of cytochrome p450 (CYP) 1A1, CYP1B1, glutathione S-transferase (GST) M1, and GSTT1 genes in a case control study. Polymorphisms were examined in 114 bladder cancer patients and 114 age and sex-matched cancer-free subjects. Genotypes were determined using allele specific PCR for CYP1A1 and CYP1B1 genes, and by multiplex PCR and melting curve analysis for GSTM1 and GSTT1 genes. Our results revealed a statistically significant increased bladder cancer risk for GSTT1 null genotype carriers with an odds ratio of 3.06 (95% confidence interval=1.39-6.74, p=0.006). Differences of CYP1A1, CYP1B1 and GSTM1 genotype frequencies were not statistically significant between patients and controls. However, the specific combination of GSTM1 null, GSTT1 null, and CYP1B1 codon 119 risk allele carriers and specific combination of GSTM1 present, GSTT1 null, and CYP1B1 432 risk allele carriers exhibited increased cancer risk in the combined analysis. We did not observe any association between different genotype groups and prognostic tumor characteristics of bladder cancer. Our results indicate that inherited absence of GSTT1 gene may be associated with bladder cancer susceptibility, and specific combinations of GSTM1, GSTT1 and CYP1B1 gene polymorphisms may modify bladder cancer risk in the Turkish population, without any association being observed for CYP1A1 gene polymorphism and bladder cancer risk.

  1. Association of genetic variants of xenobiotic and estrogen metabolism pathway (CYP1A1 and CYP1B1) with gallbladder cancer susceptibility.

    PubMed

    Sharma, Kiran Lata; Agarwal, Akash; Misra, Sanjeev; Kumar, Ashok; Kumar, Vijay; Mittal, Balraj

    2014-06-01

    Gallbladder carcinoma is a highly aggressive cancer with female predominance. Interindividual differences in the effectiveness of the activation/detoxification of environmental carcinogens and endogenous estrogens may play a crucial role in cancer susceptibility. The present study included 410 patients with carcinoma of the gallbladder (GBC) and 230 healthy subjects. This study examined association of CYP1A1-MspI, CYP1A1-Ile462Val, and CYP1B1-Val432Leu with GBC susceptibility. CYP1A1-MspI [CC] and CYP1A1-Ile462Val [iso/val] genotypes were found to be significantly associated with GBC (p=0.006 and p=0.03, respectively), as compared to healthy controls, while CYP1B1-Val432Leu was not associated with GBC. The CYP1A1 haplotype [C-val] showed a significant association with GBC (p=0.006). On stratification based on gender, the CYP1A1-MspI [CC] genotype showed an increased risk of GBC in females (p=0.018). In case-only analysis, tobacco users with CYP1A1-MspI [CT] genotypes were at a higher risk of GBC (p=0.008). Subdividing the GBC patients on the basis of gallstone status, the CYP1A1 haplotype [C-val] imparted a higher risk in patients without stones when compared to controls (p=0.001). The results remained significant even after applying Bonferroni correction. Multivariate analysis revealed an increased risk of CYP1A1 iso/val and val/val genotypes in GBC patients having BMI >25 (p=0.021). The CYP1A1 polymorphisms may confer increased risk of GBC, probably due to impaired xenobiotic or hormone metabolism through a gallstone-independent pathway.

  2. Rats fed soy protein isolate (SPI) have impaired hepatic CYP1A1 induction by polycyclic aromatic hydrocarbons as a result of interference with aryl hydrocarbon receptor signaling

    SciTech Connect

    Singhal, Rohit; Badger, Thomas M.; Ronis, Martin J.

    2008-03-01

    Consumption of soy diets has been found to reduce cancer incidence in animals and is associated with reduced cancer risk in humans. Previously, we have demonstrated that female Sprague-Dawley rats fed purified AIN-93G diets with soy protein isolate (SPI) as the sole protein source had reduced CYP1A1 induction and basal aryl hydrocarbon receptor (AhR) levels relative to those fed the same diet containing casein (CAS). In the present study, the molecular mechanisms underlying reduced AhR expression have been studied. The SPI-effect on AhR was not observed after feeding diets containing the purified soy isoflavones genistein or daidzein. Rat hepatoma FGC-4 cells were treated with the serum obtained from rats fed CAS- or SPI-containing diets. Reduced AhR levels (P < 0.05) were observed after 24 h exposure to SPI-serum without any changes in the overall expression of chaperone proteins-HSP90 and XAP2. SPI-serum-stimulated AhR degradation was inhibited by treating the cells with the proteasome inhibitor, MG132, and was observed to be preceded by ubiquitination of the receptor. A reduced association of XAP2 with the immunoprecipitated AhR complex was observed. SPI-serum-mediated AhR degradation was preceded by nuclear translocation of the receptor. However, the translocated receptor was found to be unable to heterodimerize with ARNT or to bind to XRE elements on the CYP1A1 enhancer. These data suggest that feeding SPI-containing diets antagonizes AhR signaling by a novel mechanism which differs from those established for known AhR antagonists.

  3. The association of the CYP1A1 Ile462Val polymorphism with head and neck cancer risk: evidence based on a cumulative meta-analysis

    PubMed Central

    Wang, Yadong; Yang, Haiyan; Duan, Guangcai; Wang, Haiyu

    2016-01-01

    Objective The aim of this study was to address the association between the Ile462Val polymorphism in the gene encoding cytochrome P450 1A1 (CYP1A1) and the risk of head and neck cancer (HNC). Materials and methods The Medline/PubMed, EMBASE, and Web of Science databases were searched. The strength of the association was evaluated by calculating the odds ratio (OR) with a 95% confidence interval (CI). Results Overall, we observed an increased risk of HNC in patients with the Ile/Val+Val/Val genotype compared to those with the Ile/Ile genotype among the 6,367 cases and 6,395 controls evaluated in the 34 eligible studies, with a pooled OR of 1.284 (95% CI: 1.119–1.473). In addition, we observed an increased risk of HNC in patients with the Ile/Val+Val/Val genotype compared to those with the Ile/Ile genotype in the subgroup analyses (OR =1.362, 95% CI: 1.102–1.685 for laryngeal cancer; OR =1.519, 95% CI: 1.253–1.843 for pharyngeal cancer; OR =1.371, 95% CI: 1.111–1.693 for Asians; and OR =1.329, 95% CI: 1.138–1.551 for patients in studies using hospital-based controls). Conclusion This cumulative meta-analysis suggests that the CYP1A1 Ile462Val polymorphism might contribute to the risk of HNC, particularly for pharyngeal cancer and laryngeal cancer. PMID:27274286

  4. CYP1A1, GSTM1, GSTT1 and TP53 Polymorphisms and Risk of Gallbladder Cancer in Bolivians.

    PubMed

    Sakai, Kazuaki; Loza, Ernesto; Roig, Guido Villa-Gomez; Nozaki, Ryoko; Asai, Takao; Ikoma, Toshikazu; Tsuchiya, Yasuo; Kiyohara, Chikako; Yamamoto, Masaharu; Nakamura, Kazutoshi

    2016-01-01

    The Plurinational State of Bolivia (Bolivia) has a high incidence rate of gallbladder cancer (GBC). However, the genetic and environmental risk factors for GBC development are not well understood. We aimed to assess whether or not cytochrome P450 (CYP1A1), glutathione S-transferase mu 1 (GSTM1), theta 1 (GSTT1) and tumor suppressor protein p53 (TP53) genetic polymorphisms modulate GBC susceptibility in Bolivians. This case-control study covered 32 patients with GBC and 86 healthy subjects. GBC was diagnosed on the basis of histological analysis of tissues at the Instituto de Gastroenterologia Boliviano-Japones (IGBJ); the healthy subjects were members of the staff at the IGBJ. Distributions of the CYP1A1 rs1048943 and TP53 rs1042522 polymorphisms were assayed using PCR-restriction fragment length polymorphism assay. GSTM1 and GSTT1 deletion polymorphisms were detected by a multiplex PCR assay. The frequency of the GSTM1 null genotype was significantly higher in GBC patients than in the healthy subjects (odds ratio [OR], 2.35; 95% confidence interval [CI], 1.03-5.37; age-adjusted OR, 3.53; 95% CI, 1.29-9.66; age- and sex-adjusted OR, 3.40; 95% CI, 1.24-9.34). No significant differences were observed in the frequencies of CYP1A1, GSTT1, or TP53 polymorphisms between the two groups. The GSTM1 null genotype was associated with increased GBC risk in Bolivians. Additional studies with larger control and case populations are warranted to confirm the association between the GSTM1 deletion polymorphism and GBC risk suggested in the present study.

  5. Genetic polymorphism of CYP1A1 and CYP2D6 in the Tundra Nentsi population of Siberia.

    PubMed

    Lyakhovich, V V; Mitrofanov, D V; Gutkina, N I; Duzhak, T G; Posukh, O L; Osipova, L P

    1998-01-01

    The purpose of this study was to establish the frequencies of CYP1A1 and CYP2D6 polymorphic genotypes in the Tundra Nentsi population, which is a small indigenous northern people living in Siberia and belonging to the Northern Mongoloid race. The frequencies of Ile/Ile, Ile/Val, and Val/Val genotypes in the Tundra Nentsi population, as determined by means of the allele-specific PCR, were 50.8%, 39.2%, and 10%, respectively. Thus, the Val allele frequency in Tundra Nentsi appeared to be as high (29.5%) as in the Japanese population (25%) reported elsewhere. Those frequencies in the reference group of Siberian Caucasians were in good agreement with the data reported elsewhere for other Caucasians, although the Val allele frequency observed in Siberia inhabitants (5.7%) was somewhat higher than those frequencies obtained for other Caucasian populations. By means of PCR followed by specific-site digestion with MvaI endonuclease, we analysed the frequencies of CYP2D6B allele in the Tundra Nentsi population. The frequencies of 2D6wt/2D6wt and 2D6wt/B in the group of 120 Nentsi were 84.2% and 15.8%, respectively, with no subject possessing the 2D6B/2D6B genotype. The group of Siberian Caucasians represented those frequencies as 67.7%, 27.1%, and 5.2%, respectively. In total, the frequency of CYP2D6B allele in the Tundra Nentsi population was half that in Caucasians (8.3% vs. 19%). Taken together, our data indicate that the frequencies of CYP2D6B and Val allele of CYP1A1 in Tundra Nentsi population are different from those obtained for Caucasians. We also found similarities in the CYP1A1 mutation frequencies in the Tundra Nentsi and Japanese populations.

  6. Susceptibility to oral squamous cell carcinoma: correlation with variants of CYP1A1-MspI, GSTT1, GSTM1, ALDH2, EC-SOD and Lifestyle factors

    PubMed Central

    Wang, L-J; Liu, L-Z; Ma, S-N

    2016-01-01

    Abstract In order to investigate the association between polymorphisms in genes encoding metabolizing enzymes (CYP1A1-MspI, EC-SOD (extracellular superoxide dismutase), GSTT1, GSTM1, ALDH2), cigarette and alcohol consumption, and the risk of oral squamous cell carcinoma, we conducted a prospective case-control study comprised of 750 individuals with oral squamous cell carcinoma (OSCC) and 750 healthy individuals. Data about smoking and drinking habits were collected along with other demographic and clinical information. Peripheral blood samples were collected for DNA extraction, and polymerase chain reaction (PCR) and PCR-RFLP (restriction fragment length polymorphism) were used to determine genotypes of CYP1A1, EC-SOD, GSTT1, GSTM1, ALDH2. The results showed that smoking and alcohol consumption were significantly more common among patients than controls (p <0.05). There were significant differences in the genotype distribution for each locus between groups, with the CYP1A1 (m2/ m2), EC-SOD (C/G), GSTT1 [–], GSTM1 [–] and ALDH2 (non G/G) genotypes being more common among patients (p <0.05). Furthermore, the majority of patients had at least two or more variant genotypes, while controls had one or no variant genotype (p <0.05). Finally, multiple variant genotypes combined with smoking, drinking, or both smoking and drinking significantly increased the risk of OSCC, with greater increase for heavier smoking/drinking. In brief, genetic polymorphism of CYP1A1, EC-SOD, GSTT1, GSTM1, and ALDH2 and smoking and drinking history are closely associated with susceptibility to OSCC. PMID:28289590

  7. Induction of CYP1A1 and CYP1B1 by benzo(k)fluoranthene and benzo(a)pyrene in T-47D human breast cancer cells: Roles of PAH interactions and PAH metabolites

    SciTech Connect

    Spink, David C. Wu, Susan J.; Spink, Barbara C.; Hussain, Mirza M.; Vakharia, Dilip D.; Pentecost, Brian T.; Kaminsky, Laurence S.

    2008-02-01

    The interactions of polycyclic aromatic hydrocarbons (PAH) and cytochromes P450 (CYP) are complex; PAHs are enzyme inducers, substrates, and inhibitors. In T-47D breast cancer cells, exposure to 0.1 to 1 {mu}M benzo(k)fluoranthene (BKF) induced CYP1A1/1B1-catalyzed 17{beta}-estradiol (E{sub 2}) metabolism, whereas BKF levels greater than 1 {mu}M inhibited E{sub 2} metabolism. Time course studies showed that induction of CYP1-catalyzed E{sub 2} metabolism persisted after the disappearance of BKF or co-exposed benzo(a)pyrene, suggesting that BKF metabolites retaining Ah receptor agonist activity were responsible for prolonged CYP1 induction. BKF metabolites were shown, through the use of ethoxyresorufin O-deethylase and CYP1A1-promoter-luciferase reporter assays to induce CYP1A1/1B1 in T-47D cells. Metabolites formed by oxidation at the C-2/C-3 region of BKF had potencies for CYP1 induction exceeding those of BKF, whereas C-8/C-9 oxidative metabolites were somewhat less potent than BKF. The activities of expressed human CYP1A1 and 1B1 with BKF as substrate were investigated by use of HPLC with fluorescence detection, and by GC/MS. The results showed that both enzymes efficiently catalyzed the formation of 3-, 8-, and 9-OHBKF from BKF. These studies indicate that the inductive effects of PAH metabolites as potent CYP1 inducers are likely to be additional important factors in PAH-CYP interactions that affect metabolism and bioactivation of other PAHs, ultimately modulating PAH toxicity and carcinogenicity.

  8. Aryl hydrocarbon hydroxylase represents CYP1B1, and not CYP1A1, in human freshly isolated white cells: trimodal distribution of Japanese population according to induction of CYP1B1 mRNA by environmental dioxins.

    PubMed

    Toide, Kenji; Yamazaki, Hiroshi; Nagashima, Rikako; Itoh, Keisuke; Iwano, Shunsuke; Takahashi, Yoshiki; Watanabe, Shaw; Kamataki, Tetsuya

    2003-03-01

    The expression level of mRNAs for cytochrome P450 (CYP) 1A1 and 1B1 in freshly prepared white cells from 72 subjects exposed to dioxins at waste incinerators was investigated. The amounts of CYP1B1 mRNA ranged from 0.16 to 671 molecules/10(7) molecules of 18S rRNA, whereas the amounts of CYP1A1 mRNA were <6 molecules/10 ng total RNA, indicating that CYP1A1 was not induced to a detectable level by environmentally exposed dioxins. The inducibility of CYP1B1 mRNA in leukocytes, defined as the ratio of CYP1B1 mRNA to the plasma concentration of dioxins, varied among the subjects. It was found that the subjects showed trimodal distribution according to inducibility: 39 (54.2%), 25 (34.7%), and 8 (11.1%) of 72 subjects were judged as poor, intermediate, and high responders to environmental dioxins, respectively. The amounts of CYP1B1 mRNA in leukocytes of the intermediate and high responders were highly correlated with the plasma concentrations of dioxins (P < 0.05 and <0.01). These results suggest that CYP1B1 with polymorphic inducibility by dioxins is involved in aromatic hydrocarbon hydroxylase activities in human lymphocytes.

  9. Susceptibility to endometrial cancer: influence of allelism at p53, glutathione S-transferase (GSTM1 and GSTT1) and cytochrome P-450 (CYP1A1) loci.

    PubMed Central

    Esteller, M.; García, A.; Martínez-Palones, J. M.; Xercavins, J.; Reventós, J.

    1997-01-01

    A case-control study was designed to identify associations between polymorphisms at p53, cytochrome P-450 (CYP1A1) and glutathione-S-transferases and endometrial cancer susceptibility. Among all polymorphisms analysed, an insertional variant in p53 (P53PIN3) and two polymorphisms in the 3'-end and exon 7 of CYP1A1 showed significant association with enhanced endometrial cancer risk. Images Figure 1 Figure 2 PMID:9155064

  10. Renal Nitric Oxide Synthase and Antioxidant Preservation in Cyp1a1-Ren-2 Transgenic Rats With Inducible Malignant Hypertension

    PubMed Central

    2013-01-01

    BACKGROUND Dietary administration of 0.30% indole-3-carbinol (I3C) to Cyp1a1-Ren2 transgenic rats (TGRs) generates angiotensin II (ANG II)–dependent malignant hypertension (HTN) and increased renal vascular resistance. However, TGRs with HTN maintain a normal or slightly reduced glomerular filtration rate. We tested the hypothesis that maintenance of renal function in hypertensive Cyp1a1-Ren2 TGRs is due to preservation of the intrarenal nitric oxide (NO) and antioxidant systems. METHODS Kidney cortex, kidney medulla, aortic endothelial (e) and neuronal (n) nitric oxide synthase (NOS), superoxide dismutases (SODs), and p22phox (nicotinamide adenine dinucleotide phosphate-oxidase subunit) protein abundances were measured along with kidney cortex total antioxidant capacity (TAC) and NOx. TGRs were fed a normal diet that contained 0.3% I3C or 0.3% I3C + candesartan (AT1 receptor antagonist; 25mg/L in drinking water) (n = 5–6 per group) for 10 days. RESULTS Blood pressure increased and body weight decreased in I3C-induced TGRs, while candesartan blunted these responses. Abundances of NOS, SOD, and p22phox as well as TAC were maintained in the kidney cortex of I3C-induced TGRs with and without candesartan, while kidney cortex NOx production increased in both groups. Kidney medulla eNOS and extracellular (EC) SOD decreased and nNOS were unchanged in both groups of I3C-induced TGRs. In addition, a compensatory increase occurred in kidney medulla Mn SOD in I3C-induced TGRs + candesartan. Aortic eNOS and nNOS∝ fell and p22phox and Mn SOD increased in hypertensive I3C-induced TGRs; all changes were reversed with candesartan. CONCLUSIONS The preservation of renal cortical NO and antioxidant capacity is associated with preserved renal function in Cyp1a1-Ren2 TGRs with ANG II-dependent malignant HTN. PMID:23764378

  11. Transgenic Overexpression of Aryl Hydrocarbon Receptor Repressor (AhRR) and AhR-Mediated Induction of CYP1A1, Cytokines, and Acute Toxicity

    PubMed Central

    Vogel, Christoph F.A.; Chang, W.L. William; Kado, Sarah; McCulloh, Kelly; Vogel, Helena; Wu, Dalei; Haarmann-Stemmann, Thomas; Yang, GuoXiang; Leung, Patrick S.C.; Matsumura, Fumio; Gershwin, M. Eric

    2016-01-01

    Background: The aryl hydrocarbon receptor repressor (AhRR) is known to repress aryl hydrocarbon receptor (AhR) signaling, but very little is known regarding the role of the AhRR in vivo. Objective: This study tested the role of AhRR in vivo in AhRR overexpressing mice on molecular and toxic end points mediated through a prototypical AhR ligand. Methods: We generated AhRR-transgenic mice (AhRR Tg) based on the genetic background of C57BL/6J wild type (wt) mice. We tested the effect of the prototypical AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the expression of cytochrome P450 (CYP)1A1 and cytokines in various tissues of mice. We next analyzed the infiltration of immune cells in adipose tissue of mice after treatment with TCDD using flow cytometry. Results: AhRR Tg mice express significantly higher levels of AhRR compared to wt mice. Activation of AhR by TCDD caused a significant increase of the inflammatory cytokines Interleukin (IL)-1β, IL-6 and IL-10, and CXCL chemokines in white epididymal adipose tissue from both wt and AhRR Tg mice. However, the expression of IL-1β, CXCL2 and CXCL3 were significantly lower in AhRR Tg versus wt mice following TCDD treatment. Exposure to TCDD caused a rapid accumulation of neutrophils and macrophages in white adipose tissue of wt and AhRR Tg mice. Furthermore we found that male AhRR Tg mice were protected from high-dose TCDD-induced lethality associated with a reduced inflammatory response and liver damage as indicated by lower levels of TCDD-induced alanine aminotransferase and hepatic triglycerides. Females from both wt and AhRR Tg mice were less sensitive than male mice to acute toxicity induced by TCDD. Conclusion: In conclusion, the current study identifies AhRR as a previously uncharacterized regulator of specific inflammatory cytokines, which may protect from acute toxicity induced by TCDD. Citation: Vogel CF, Chang WL, Kado S, McCulloh K, Vogel H, Wu D, Haarmann-Stemmann T, Yang GX, Leung PS, Matsumura F

  12. Modulation of CYP1A1 and CYP1A2 hepatic enzymes after oral administration of Chios mastic gum to male Wistar rats.

    PubMed

    Katsanou, Efrosini S; Kyriakopoulou, Katerina; Emmanouil, Christina; Fokialakis, Nikolas; Skaltsounis, Alexios-Leandros; Machera, Kyriaki

    2014-01-01

    Chios mastic gum (CMG), a resin derived from Pistacia lentiscus var. chia, is known since ancient times for its pharmacological activities. CYP1A1 and CYP1A2 enzymes are among the most involved in the biotransformation of chemicals and the metabolic activation of pro-carcinogens. Previous studies referring to the modulation of these enzymes by CMG have revealed findings of unclear biological and toxicological significance. For this purpose, the modulation of CYP1A1 and CYP1A2 enzymes in the liver of male Wistar rats following oral administration of CMG extract (CMGE), at the levels of mRNA and CYP1A1 enzyme activity, was compared to respective enzyme modulation following oral administration of a well-known bioactive natural product, caffeine, as control compound known to involve hepatic enzymes in its metabolism. mRNA levels of Cyp1a1 and Cyp1a2 were measured by reverse transcription real-time polymerase chain reaction and their relative quantification was calculated. CYP1A1 enzyme induction was measured through the activity of ethoxyresorufin-O-deethylase (EROD). The results indicated that administration of CMGE at the recommended pharmaceutical dose does not induce significant transcriptional modulation of Cyp1a1/2 and subsequent enzyme activity induction of CYP1A1 while effects of the same order of magnitude were observed in the same test system following the administration of caffeine at the mean daily consumed levels. The outcome of this study further confirms the lack of any toxicological or biological significance of the specific findings on liver following the administration of CMGE.

  13. Prenatal 3,3',4,4',5-pentachlorobiphenyl exposure modulates induction of rat hepatic CYP 1A1, 1B1, and AhR by 7,12-dimethylbenz[a]anthracene

    SciTech Connect

    Wakui, Shin . E-mail: wakui@azabu-u.ac.jp; Yokoo, Kiyofumi; Takahashi, Hiroyuki; Muto, Tomoko; Suzuki, Yoshihiko; Kanai, Yoshikatsu; Hano, Hiroshi; Furusato, Masakuni; Endou, Hitoshi

    2006-02-01

    We previously reported the finding that prenatal exposure to a relatively low dose of PCB126 increases the rate of DMBA-induced rat mammary carcinoma, while a high dose decreased it. One of the most important factors determining the sensitivity to mammary carcinogenesis is the metabolic stage at administration of the carcinogenic agent. DMBA is a procarcinogen that recruits the host metabolism to yield its ultimate carcinogenic form, and CYP1A1 and CYP1B1 (CYP1) conduct this metabolism. We investigated the hepatic expression of CYP1 and AhR following oral administration of DMBA (100 mg/kg b.w.) (i.g.) to 50-day-old female Sprague-Dawley rats whose dams had been treated (i.g.) with 2.5 ng, 250 ng, 7.5 {mu}g of PCB126/kg or the vehicle on days 13 to 19 post-conception. Real-time quantitative RT-PCR analysis revealed that the prenatal exposure to a relatively low dose of PCB126 (the 250 ng group) prolonged the higher expression of CYP1A1, CYP1B1, and AhR mRNA, while prenatal exposure to a high dose of PCB126 (the 7.5 {mu}g group) prolonged the higher expression of CYP1A1 and AhR mRNA. Western blotting and immunohistochemical analyses were consistent with mRNAs changes. Because DMBA oxidation produces a highly mutagenic metabolite and is finally catalyzed by CYP1B1, a relatively low PCB126 dose might produce the biological character to potentially increase the risk of DMBA-induced mammary carcinoma.

  14. Sulforaphane inhibits CYP1A1 activity and promotes genotoxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in vitro

    SciTech Connect

    Yang, Fangxing; Zhuang, Shulin; Zhang, Chao; Dai, Heping; Liu, Weiping

    2013-06-15

    Increasing environmental pollution by carcinogens such as some of persistent organic pollutants (POPs) has prompted growing interest in searching for chemopreventive compounds which are readily obtainable. Sulforaphane (SFN) is isolated from cruciferous vegetables and has the potentials to reduce carcinogenesis through various pathways. In this study, we studied the effects of SFN on CYP1A1 activity and genotoxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The results showed that SFN inhibited TCDD-induced CYP1A1 activity in H4IIE cells by directly inhibiting CYP1A1 activity, probably through binding to aryl hydrocarbon receptor and/or CYP1A1 revealed by molecular docking. However, SFN promoted TCDD-induced DNA damage in yeast cells and reduced the viability of initiated yeast cells. Besides, it is surprising that SFN also failed to reduce genotoxicity induced by other genotoxic reagents which possess different mechanisms to lead to DNA damage. Currently, it is difficult to predict whether SFN has the potentials to reduce the risk of TCDD based on the conflicting observations in the study. Therefore, further studies should be urgent to reveal the function and mechanism of SFN in the stress of such POPs on human health. - Highlights: • Sulforaphane inhibited TCDD-induced CYP1A1 activity in H4IIE cells. • Sulforaphane may bind to aryl hydrocarbon receptor and/or CYP1A1. • Sulforaphane promoted TCDD-induced DNA damage in yeast cells. • Sulforaphane may promote DNA damage by DNA strand breaks or DNA alkylation.

  15. Is hepatic cytochrome P4501A1 expression predictive of hepatic burdens of dioxins, furans, and PCBs in Atlantic tomcod from the Hudson River estuary?

    PubMed

    Yuan, Z; Wirgin, M; Courtenay, S; Ikonomou, M; Wirgin, I

    2001-10-01

    Hepatic cytochrome P4501A1 (CYP1A1) expression in fishes is frequently used to evaluate bioavailable aromatic hydrocarbon contamination of aquatic ecosystems. In controlled laboratory experiments, CYP1A1 expression in naïve fishes is usually dose-responsive to aromatic hydrocarbons and in field studies levels of gene expression in natural populations often correspond with known levels of sediment-borne contaminants. We quantified CYP1A1 mRNA levels in juvenile Atlantic tomcod Microgadus tomcod from 42 sites in the Hudson River estuary to evaluate the correspondence between hepatic CYP1A1 expression and hepatic concentrations of persistent halogenated aromatic hydrocarbons and to determine the utility of CYP1A1 expression as a biomarker in evaluating the microgeographic distribution of bioavailable contaminants within a large aquatic ecosystem. We found significant spatial heterogeneity in CYP1A1 mRNA levels among collection sites with levels of gene expression differing in some cases by 23-34 folds. CYP1A1 mRNA expression was highest in tomcod from the Newark Bay complex and lowest in tomcod from the most upriver collection sites in the main stem of the Hudson River. Although levels of PCDDs, PCDFs, and PCBs expressed as TCDD TEQs and CYP1A1 mRNA were highest in tomcod from the Newark Bay complex, there was no relationship between hepatic halogenated aromatic hydrocarbon levels and hepatic CYP1A1 mRNA in tomcod from sites in the main stem of the Hudson River. These results suggest that levels of CYP1A1 expression in fish from sites highly polluted with mixtures of halogenated aromatic hydrocarbons and other xenobiotics may not always be reflective of levels of bioavailable aromatic hydrocarbon contaminants. Based on these results and earlier controlled laboratory experiments, we hypothesize that elevated levels of CYP1A1 expression in tomcod from the Hudson River may be due primarily to PAHs or other contaminants not measured in this study.

  16. Antimutagenic properties of Mangifera indica L. stem bark extract and evaluation of its effects on hepatic CYP1A1.

    PubMed

    Morffi, Janet; Rodeiro, Idania; Hernández, Sandra Luz; González, Leonora; Herrera, Jose; Espinosa-Aguirre, J Javier

    2012-09-01

    Mangifera indica stem bark extract (MSBE) is a Cuban natural product which has shown strong antioxidant properties. In this work, the antimutagenic effect of MSBE was tested against 10 well-known mutagens/carcinogens in the Ames test in the absence or presence of metabolic fraction (S9). The chemical mutagens tested included: cyclophosphamide, mitomycin C, bleomycin, cisplatin, dimethylnitrosamine (DMNA), benzo[a]pyrene (BP), 2-acetylaminofluorene (2-AAF), sodium azide, 1-nitropyrene (1-NP) and picrolonic acid. Protective effects of the extract were also evaluated by comparing the efficiency of S9 fraction obtained from rats treated during 28 days with oral doses of MSBE (50-500 mg/kg) with that obtained from rats treated with vehicle (control) to activate bleomycin and cyclophosphamide in the Ames test. MSBE concentrations between 50 and 500 μg/plate significantly reduced the mutagenicity mediated by all the chemicals tested with the exception of sodium azide. Higher mutagenicity was found when bleomycin and cyclophosphamide (CP) were activated by control S9 than by MSBE S9. In addition, inhibition of CYP1A1 microsomal activity was observed in the presence of MSBE (10-20 μg/ml). We can conclude that besides its potent antioxidant activity previously reported, MSBE may also exert a chemoprotective effect due to its capacity to inhibit CYP activity.

  17. Phase I Metabolic Genes and Risk of Lung Cancer: Multiple Polymorphisms and mRNA Expression

    PubMed Central

    Rotunno, Melissa; Yu, Kai; Lubin, Jay H.; Consonni, Dario; Pesatori, Angela C.; Goldstein, Alisa M.; Goldin, Lynn R.; Wacholder, Sholom; Burdette, Laurie; Chanock, Stephen J.; Bertazzi, Pier Alberto; Tucker, Margaret A.; Caporaso, Neil E.; Chatterjee, Nilanjan; Bergen, Andrew W.; Landi, Maria Teresa

    2009-01-01

    Polymorphisms in genes coding for enzymes that activate tobacco lung carcinogens may generate inter-individual differences in lung cancer risk. Previous studies had limited sample sizes, poor exposure characterization, and a few single nucleotide polymorphisms (SNPs) tested in candidate genes. We analyzed 25 SNPs (some previously untested) in 2101 primary lung cancer cases and 2120 population controls from the Environment And Genetics in Lung cancer Etiology (EAGLE) study from six phase I metabolic genes, including cytochrome P450s, microsomal epoxide hydrolase, and myeloperoxidase. We evaluated the main genotype effects and genotype-smoking interactions in lung cancer risk overall and in the major histology subtypes. We tested the combined effect of multiple SNPs on lung cancer risk and on gene expression. Findings were prioritized based on significance thresholds and consistency across different analyses, and accounted for multiple testing and prior knowledge. Two haplotypes in EPHX1 were significantly associated with lung cancer risk in the overall population. In addition, CYP1B1 and CYP2A6 polymorphisms were inversely associated with adenocarcinoma and squamous cell carcinoma risk, respectively. Moreover, the association between CYP1A1 rs2606345 genotype and lung cancer was significantly modified by intensity of cigarette smoking, suggesting an underling dose-response mechanism. Finally, increasing number of variants at CYP1A1/A2 genes revealed significant protection in never smokers and risk in ever smokers. Results were supported by differential gene expression in non-tumor lung tissue samples with down-regulation of CYP1A1 in never smokers and up-regulation in smokers from CYP1A1/A2 SNPs. The significant haplotype associations emphasize that the effect of multiple SNPs may be important despite null single SNP-associations, and warrants consideration in genome-wide association studies (GWAS). Our findings emphasize the necessity of post-GWAS fine mapping and

  18. Rats fed soy protein isolate (SPI) have impaired hepatic CYP1A1 induction by polycyclic aromatic hydrocarbons as a result of interference with aryl hydrocarbon receptor signaling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumption of soy diet has been found to reduce cancer incidence in animals and is associated with reduced cancer risk in humans. Previously, we have demonstrated that female Sprague-Dawley rats fed purified AIN-93G diets with soy protein isolate (SPI) as the sole protein source had reduced CYP1A1 ...

  19. Epigenetic inactivation of the dioxin-responsive cytochrome P4501A1 gene in human prostate cancer.

    PubMed

    Okino, Steven T; Pookot, Deepa; Li, Long-Cheng; Zhao, Hong; Urakami, Shinji; Shiina, Hiroaki; Igawa, Mikio; Dahiya, Rajvir

    2006-08-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD; dioxin) is a toxic environmental contaminant that works through dioxin response elements (DRE) to activate gene expression. We tested the hypothesis that cancer-related epigenetic changes suppress dioxin activation of the cytochrome P4501A1 (CYP1A1) gene. 5-Aza-2'-deoxycytidine (5-aza-CdR), an inhibitor of DNA methylation, increases TCDD-inducible CYP1A1 mRNA expression in cancerous LNCaP cells but not in noncancerous PWR-1E and RWPE-1 cells (all human prostate cell lines). Bisulfite DNA sequencing shows that the TCDD-responsive CYP1A1 enhancer is highly methylated in LNCaP cells but not in RWPE-1 cells. In vivo footprinting experiments reveal that unmethylated DRE sites do not bind protein in response to TCDD in LNCaP cells, whereas inducible DRE occupancy occurs in RWPE-1 cells. Pretreatment of LNCaP cells with 5-aza-CdR partially restores TCDD-inducible DRE occupancy, showing that DNA methylation indirectly suppresses DRE occupancy. Chromatin immunoprecipitation experiments reveal that LNCaP cells lack trimethyl histone H3 lysine 4, a mark of active genes, on the CYP1A1 regulatory region, whereas this histone modification is prevalent in PWR-1E and RWPE-1 cells. We also analyzed CYP1A1 enhancer methylation in human prostate tissue DNA. We do not detect CYP1A1 enhancer methylation in 30 DNA samples isolated from noncancerous prostate tissue. In contrast, 11 of 30 prostate tumor DNA samples have detectable CYP1A1 enhancer methylation, indicating that it is hypermethylated in prostate tumors. This is the first report that shows that CYP1A1 is aberrantly hypermethylated in human prostate cancer and has an altered, inaccessible chromatin structure that suppresses its dioxin responsiveness.

  20. SIN3A, generally regarded as a transcriptional repressor, is required for induction of gene transcription by the aryl hydrocarbon receptor.

    PubMed

    Solaimani, Parrisa; Wang, Feng; Hankinson, Oliver

    2014-11-28

    CYP1A1 bioactivates several procarcinogens and detoxifies several xenobiotic compounds. Transcription of CYP1A1 is highly induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) via the aryl hydrocarbon receptor. We recently described an RNAi high throughput screening performed in the Hepa-1 mouse hepatoma cell line, which revealed that SIN3A is necessary for the induction of CYP1A1-dependent ethoxyresorufin-o-deethylase (EROD) enzymatic activity by TCDD. In the current studies, we sought to provide insight into the role of SIN3A in this process, particularly because studies on SIN3A have usually focused on its repressive activity on transcription. We report that ectopic expression of human SIN3A in Hepa-1 cells enhanced EROD induction by TCDD and efficiently rescued TCDD induction of EROD activity in cells treated with an siRNA to mouse SIN3A, thus validating a role for SIN3A in CYP1A1 induction. We demonstrate that SIN3A is required for TCDD induction of the CYP1A1 protein in Hepa-1 cells but not for expression of the aryl hydrocarbon receptor protein. In addition, siRNAs for SIN3A decreased TCDD-mediated induction of CYP1A1 mRNA and EROD activity in human hepatoma cell line Hep3B. We establish that TCDD treatment of Hepa-1 cells rapidly increases the degree of SIN3A binding to both the proximal promoter and enhancer of the Cyp1a1 gene and demonstrate that increased binding to the promoter also occurs in human Hep3B, HepG2, and MCF-7 cells. These studies establish that SIN3A physically interacts with the CYP1A1 gene and extends the transcriptional role of SIN3A to a gene that is very rapidly and dramatically induced.

  1. SIN3A, Generally Regarded as a Transcriptional Repressor, Is Required for Induction of Gene Transcription by the Aryl Hydrocarbon Receptor*

    PubMed Central

    Solaimani, Parrisa; Wang, Feng; Hankinson, Oliver

    2014-01-01

    CYP1A1 bioactivates several procarcinogens and detoxifies several xenobiotic compounds. Transcription of CYP1A1 is highly induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) via the aryl hydrocarbon receptor. We recently described an RNAi high throughput screening performed in the Hepa-1 mouse hepatoma cell line, which revealed that SIN3A is necessary for the induction of CYP1A1-dependent ethoxyresorufin-o-deethylase (EROD) enzymatic activity by TCDD. In the current studies, we sought to provide insight into the role of SIN3A in this process, particularly because studies on SIN3A have usually focused on its repressive activity on transcription. We report that ectopic expression of human SIN3A in Hepa-1 cells enhanced EROD induction by TCDD and efficiently rescued TCDD induction of EROD activity in cells treated with an siRNA to mouse SIN3A, thus validating a role for SIN3A in CYP1A1 induction. We demonstrate that SIN3A is required for TCDD induction of the CYP1A1 protein in Hepa-1 cells but not for expression of the aryl hydrocarbon receptor protein. In addition, siRNAs for SIN3A decreased TCDD-mediated induction of CYP1A1 mRNA and EROD activity in human hepatoma cell line Hep3B. We establish that TCDD treatment of Hepa-1 cells rapidly increases the degree of SIN3A binding to both the proximal promoter and enhancer of the Cyp1a1 gene and demonstrate that increased binding to the promoter also occurs in human Hep3B, HepG2, and MCF-7 cells. These studies establish that SIN3A physically interacts with the CYP1A1 gene and extends the transcriptional role of SIN3A to a gene that is very rapidly and dramatically induced. PMID:25305016

  2. Induction of Cyp1a1 and Cyp1b1 and formation of DNA adducts in C57BL/6, Balb/c, and F1 mice following in utero exposure to 3-methylcholanthrene

    SciTech Connect

    Xu Mian; Nelson, Garret B.; Moore, Joseph E.; McCoy, Thomas P.; Dai, Jian; Manderville, Richard A.; Ross, Jeffrey A.; Miller, Mark Steven . E-mail: msmiller@wfubmc.edu

    2005-11-15

    Fetal mice are more sensitive to chemical carcinogens than are adults. Previous studies from our laboratory demonstrated differences in the mutational spectrum induced in the Ki-ras gene from lung tumors isolated from [D2 x B6D2F1]F2 mice and Balb/c mice treated in utero with 3-methylcholanthrene (MC). We thus determined if differences in metabolism, adduct formation, or adduct repair influence strain-specific responses to transplacental MC exposure in C57BL/6 (B6), Balb/c (BC), and reciprocal F1 crosses between these two strains of mice. The induction of Cyp1a1 and Cyp1b1 in fetal lung and liver tissue was determined by quantitative fluorescent real-time PCR. MC treatment caused maximal induction of Cyp1a1 and Cyp1b1 RNA 2-8 h after injection in both organs. RNA levels for both genes then declined in both fetal organs, but a small biphasic, secondary increase in Cyp1a1 was observed specifically in the fetal lung 24-48 h after MC exposure in all four strains. Cyp1a1 induction by MC at 4 h was 2-5 times greater in fetal liver (7000- to 16,000-fold) than fetal lung (2000- to 6000-fold). Cyp1b1 induction in both fetal lung and liver was similar and much lower than that observed for Cyp1a1, with induction ratios of 8- to 18-fold in fetal lung and 10- to 20-fold in fetal liver. The overall kinetics and patterns of induction were thus very similar across the four strains of mice. The only significant strain-specific effect appeared to be the relatively poor induction of Cyp1b1 in the parental strain of B6 mice, especially in fetal lung tissue. We also measured the levels of MC adducts and their disappearance from lung tissue by the P{sup 32} post-labeling assay on gestation days 18 and 19 and postnatal days 1, 4, 11, and 18. Few differences were seen between the different strains of mice; the parental strain of B6 mice had nominally higher levels of DNA adducts 2 (gestation day 19) and 4 (postnatal day 1) days after injection, although this was not statistically

  3. Association of CYP1A1 A4889G and T6235C polymorphisms with the risk of sporadic breast cancer in Brazilian women

    PubMed Central

    de Oliveira, Camila Borges Martins; Cardoso-Filho, Cássio; Bossi, Leonardo Silveira; Lourenço, Gustavo Jacob; Costa-Gurgel, Maria Salete; Lima, Carmen Silvia Passos

    2015-01-01

    OBJECTIVES: We examined the influence of CYP1A1 A4889G and T6235C polymorphisms on the risk of sporadic breast cancer. METHOD: DNA from 742 sporadic breast cancer patients and 742 controls was analyzed using the polymerase chain reaction, followed by the restriction fragment length polymorphism technique. RESULTS: More patients had the CYP1A1 4889AG+GG genotype compared to controls (29.0% versus 23.2%, p=0.004). The G allele carriers had a 1.50-fold increased risk (95% CI: 1.14–1.97) of sporadic breast cancer compared to the other study participants. The frequency of the 4889AG+GG genotype among the Caucasian patients was higher than in the non-Caucasian patients (30.4% versus 20.2%, p=0.03) and controls (30.4% versus 23.2%, p=0.002). Caucasians and G allele carriers had a 1.61-fold increased risk (95% CI: 1.20–2.15) of sporadic breast cancer compared to other subjects. The CYP1A1 4889AG+GG genotype was more common among patients with a younger median age at first full-term pregnancy than among controls (33.8% versus 23.2%, p=0.001) and subjects whose first full-term pregnancies occurred at an older age (33.8% versus 26.1%, p=0.03). Women with the CYP1A1 4889AG+GG genotype and earlier first full-term pregnancies had a 1.87-fold (95% CI: 1.32–2.67) increased risk of sporadic breast cancer compared to the other study participants. Excess CYP1A1 4889AG+GG (39.8% versus 27.1%, p=0.01) and 6235TC+CC (48.4% versus 35.9%, p=0.02) genotypes were also observed in patients with grade I and II tumors compared to patients with grade III tumors and controls (39.8% versus 23.2%, p=0.04; 48.4% versus 38.6%, p=0.04). The G and C allele carriers had a 2.44-fold (95% CI: 1.48–4.02) and 1.67-fold (95% CI: 1.03–2.69) increased risk, respectively, of developing grade I and II tumors compared to other subjects. CONCLUSIONS: The CYP1A1 A4889G and T6235C polymorphisms may alter the risk of sporadic breast cancer in Brazilian women. PMID:26598080

  4. Pulmonary Inflammation Impacts on CYP1A1-Mediated Respiratory Tract DNA Damage Induced by the Carcinogenic Air Pollutant Benzo[a]pyrene

    PubMed Central

    Arlt, Volker M.; Krais, Annette M.; Godschalk, Roger W.; Riffo-Vasquez, Yanira; Mrizova, Iveta; Roufosse, Candice A.; Corbin, Charmaine; Shi, Quan; Frei, Eva; Stiborova, Marie; van Schooten, Frederik-Jan; Phillips, David H.; Spina, Domenico

    2015-01-01

    Pulmonary inflammation can contribute to the development of lung cancer in humans. We investigated whether pulmonary inflammation alters the genotoxicity of polycyclic aromatic hydrocarbons (PAHs) in the lungs of mice and what mechanisms are involved. To model nonallergic acute inflammation, mice were exposed intranasally to lipopolysaccharide (LPS; 20 µg/mouse) and then instilled intratracheally with benzo[a]pyrene (BaP; 0.5 mg/mouse). BaP-DNA adduct levels, measured by 32P-postlabeling analysis, were approximately 3-fold higher in the lungs of LPS/BaP-treated mice than in mice treated with BaP alone. Pulmonary Cyp1a1 enzyme activity was decreased in LPS/BaP-treated mice relative to BaP-treated mice suggesting that pulmonary inflammation impacted on BaP-induced Cyp1a1 activity in the lung. Our results showed that Cyp1a1 appears to be important for BaP detoxification in vivo and that the decrease of pulmonary Cyp1a1 activity in LPS/BaP-treated mice results in a decrease of pulmonary BaP detoxification, thereby enhancing BaP genotoxicity (ie, DNA adduct formation) in the lung. Because less BaP was detoxified by Cyp1a1 in the lungs of LPS/BaP-treated mice, more BaP circulated via the blood to extrapulmonary tissues relative to mice treated with BaP only. Indeed, we observed higher BaP-DNA adduct levels in livers of LPS/BaP-treated mice compared with BaP-treated mice. Our results indicate that pulmonary inflammation could be a critical determinant in the induction of genotoxicity in the lung by PAHs like BaP. Cyp1a1 appears to be involved in both BaP bioactivation and detoxification although the contribution of other enzymes to BaP-DNA adduct formation in lung and liver under inflammatory conditions remains to be explored. PMID:25911668

  5. CYP1A1 and CYP1B1 polymorphisms as modifying factors in patients with pneumoconiosis and occupationally related tumours: A pilot study.

    PubMed

    Schneider, Joachim; Bernges, Ulrike

    2009-01-01

    CYP1A1 and CYP1B1 are involved in the metabolism of carcinogens. The effect of CYP1A1 and CYP1B1 polymorphisms as genetic modifiers of risk was investigated in individuals with asbestos, silica dust or ionizing radiation-induced occupational tumours compared to exposed non-cancer subjects suffering from pneumoconiosis, particularly in relation to tobacco smoking. CYP1A1 T6235C, CYP1A1 A4889G and CYP1B1 codon 432 polymorphisms were determined by real-time PCR analysis in patients with asbestos-related lung cancer (n=39), patients with diffuse malignant mesotheliomas (n=19), lung cancer in silicosis patients (n=7), uranium miners with lung cancer (UMLC) (n=40), patients with asbestosis (n=181), and silicosis patients (n=204). The results were compared to those from a healthy unexposed control group (n=50) not exposed to carcinogenic (or fibrogenic) agents in the workplace. An additional healthy control group (n=134) comprised smokers and ex-smokers. Allele frequencies were within the range described for Caucasians. Multivariate analysis revealed that patients with occupational diseases with the susceptible CYP1A1 T6235C genotype had a calculated risk ranging from OR=0.5 (95% CI 0.18-1.36) for UMLC to OR=1.23 (95% CI 0.39-4.05) for uranium miners with silicosis. The risk for patients with the susceptible CYP1A1 A4889G allele was calculated as being between OR=0.39 (95% CI 0.10-1.54) for mesothelioma patients and OR=1.54 (95% CI 0.49-4.89) for UMLC. CYP1B1 Val432Leu polymorphisms were associated with a risk of OR=0.56 (95% CI 0.2-1.55) for UMLC and OR=1.52 (95% CI 0.68-3.39) for asbestos-exposed lung cancer patients. By analyzing the interaction between tobacco smoking, type of exposure to carcinogens and the genotypes, it was determined that smoking and the presence of the susceptible genotypes did not have a combined effect. In this pilot study, the analyzed polymorphism had no consistent modifying effect on pneumoconiosis or occupationally related tumours.

  6. Associations between CYP1A1 rs1048943 A > G and rs4646903 T > C genetic variations and colorectal cancer risk: Proof from 26 case-control studies

    PubMed Central

    He, Jing; Wang, Weiye; Xue, Wenji; Wang, Yiwei; Zheng, Leizhen; Zhu, Mei-Ling

    2016-01-01

    Cytochrome P450 1A1 (CYP1A1) enzyme is one of the most important metabolizing enzymes responsible for the metabolism of numerous xenobiotics. Numerous individual case-control studies have investigated the associations between the CYP1A1 rs1048943 A > G and rs4646903 T > C genetic variations and colorectal cancer (CRC) risk, but the conclusions were controversial. To obtain a scientific conclusion, we performed a meta-analysis based on a total of 26 publications, including 20 studies with 8665 cases and 9953 controls on rs1048943 A > G and 19 studies with 6416 cases and 7551 controls on rs4646903 T > C, respectively. The pooled analysis indicated that rs1048943 A > G was associated with an increased risk of CRC (G vs. A: OR = 1.28, 95% CI = 1.08−1.52; GG vs. AA: OR = 1.54, 95% CI = 1.25−1.91; GA vs. AA: OR = 1.26, 95% CI = 1.00−1.60; GG/GA vs. AA: OR = 1.31, 95% CI = 1.05−1.64; GG vs. GA/AA: OR = 1.56, 95% CI = 1.26−1.91). Stratification analysis showed the association between rs1048943 A > G and CRC risk was more obvious in studies with the population-based (PB) design or high quality score. The association between rs4646903 T > C and CRC risk did not reach statistical significance in the pooled analysis as well as stratification analysis. This meta-analysis demonstrated CYP1A1 rs1048943 A > G may increase the susceptibility to CRC instead of rs4646903 T > C. This conclusion suggested CYP1A1 may contribute to the pathogenesis of CRC. PMID:27384991

  7. Association between CYP1A1 Ile462Val Variation and Acute Leukemia Risk: Meta-Analyses Including 2164 Cases and 4160 Controls

    PubMed Central

    Zhuo, Wenlei; Zhang, Liang; Zhu, Bo; Qiu, Zhiqun; Chen, Zhengtang

    2012-01-01

    Background Previously, CYP1A1 Ile462Val polymorphism has been indicated to be a risk factor for several malignancies. Increasing reports have focused on the association of CYP1A1 Ile462Val polymorphisms with susceptibility to acute leukemia and have generated controversial results. The goal of the present study was to derive a more precise estimation of the relationship. Methods Relevant literature has been rigorously searched and screened. Eligible studies were identified for the period up to Apr 2012. Meta-analyses evaluating the association of CYP1A1 Ile462Val variation with acute leukemia were carried out. Subgroup analyses on ethnicity, clinical types and source of controls were further performed. Results A total of thirteen publications including fourteen case-control studies with 2164 cases and 4160 controls were selected for analysis. The overall data indicated a significant association of CYP1A1 Ile462Val polymorphism with acute leukemia risk (Val/Val vs Ile/Ile OR = 1.49; 95% CI = 1.11–1.98; dominant model: OR = 1.26; 95% CI = 1.05–1.51; recessive model: OR = 1.38; 95% CI = 1.04–1.83). In subgroup analysis on ethnicity, increased risk was shown among mixed ethnicities (Val/Val vs Ile/Ile: OR = 2.36; 95% CI = 1.46–3.82; dominant model: OR = 1.37; 95% CI = 1.01–1.86; recessive model: OR = 2.20; 95% CI = 1.37–3.53) but not Asians or Caucasians. In subgroup analysis on clinical types, increased risk was observed in the acute lymphocytic leukemia (ALL) subgroup (Val/Val vs Ile/Ile: OR = 2.06; 95% CI = 1.42–3.01; recessive model: OR = 1.91; 95% CI = 1.32–2.76) but not in the acute myeloid leukemia (AML) subgroup. Conclusion The results of the present study suggest that CYP1A1 Ile462Val polymorphism might be a low-penetrant risk factor for acute leukemia. Subgroup analyses suggest that homozygous Val/Val alleles might modify the susceptibility to ALL. PMID:23056546

  8. 4-Nitrophenol exposure alters the AhR signaling pathway and related gene expression in the rat liver.

    PubMed

    Li, Ruonan; Song, Meiyan; Li, Zhi; Li, Yansen; Watanabe, Gen; Nagaoka, Kentaro; Taya, Kazuyoshi; Li, Chunmei

    2017-02-01

    4-Nitrophenol (PNP) is well known as an environmental endocrine disruptor. The aim of this study was to clarify the mechanism of PNP-induced liver damage and determine the regulatory involvement of the aryl hydrocarbon receptor (AhR) signaling pathway and associated gene expression. Immature male Wistar-Imamichi rats (28 days old) were randomly divided into control and PNP groups, which consisted of 1- and 3-day exposure (1 DE and 3 DE, respectively) and 3-day exposure followed by 3-day recovery (3 DE + 3 DR), groups. Each group was administered the vehicle or PNP (200 mg kg(-1) body weight). The body and liver weight were significantly decreased in the 3 DE group. The mRNA expression levels of estrogen receptor-α (ERα), glutathione S-transferase (GST) and AhR exhibited a significant increase in the 1 DE group whereas, in contrast, that of cytochrome P450 (CYP) 1A1 decreased significantly in the 3 DE +3 DR group. AhR and CYP1A1 proteins were detected in the cytoplasm of hepatocytes of the 1 DE and 3 DE +3 DR groups whereas the ERα protein was found in the hepatocyte nuclei of the 1 DE and 3 DE groups. The present study demonstrates that PNP activated the AhR signaling pathway and regulated related CYP1A1 and GST gene expression in the liver. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Hepatic foci in rats after diethylnitrosamine initiation and 2,3,7,8-tetrachlorodibenzo-p-dioxin promotion: evaluation of a quantitative two-cell model and of CYP 1A1/1A2 as a dosimeter.

    PubMed

    Conolly, R B; Andersen, M E

    1997-10-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent hepatic tumor promoter in female rats. We used a quantitative, stochastic initiation-promotion model based on R. B. Conolly and J. S. Kimbell (Toxicol. Appl. Pharmacol. 124, 284-295, 1994) to analyze initiation-promotion results from a previously published study (H. C. Pitot et al., Carcinogenesis 8, 1491-1499, 1987) within the context of a negative selection model of tumor promotion. In this model, two types of initiated cells (called A and B cells) are produced by DEN initiation. Visually excellent correspondence between model predictions and data (i.e., foci/cm3 liver and percentage of liver occupied by foci) are obtained when TCDD is described as having dose-responsive effects on division and death (apoptotic) rates of these two cell types. For A cells, both the division and the death rates increase while the difference between division and apoptotic rates decreases. For B cells, the difference between division and apoptotic rates increases, primarily due to a decrease in the apoptotic rate. We also linked these alterations in cell kinetics to a pharmacokinetic model for TCDD incorporating a five subcompartment model of the liver acinus with induction of CYP1A1 and 1A2 genes in the subcompartments. Alterations in A cell kinetics correlate with effects of TCDD in the region most sensitive to induction (subcompartment 5-centrilobular region); B cell dynamics correlate with induction in subcompartments 3-5 (centrilobular and mid-zonal regions). In summary, these modeling exercises show that (1) the two-cell model, without presuming effects of TCDD on the mutation rate of normal hepatocytes, reproduces the data of Pitot et al. (1987) and (2) induction of CYP1A1/1A2 in different regions of the hepatic acinus can be used as a general correlate of these presumed changes in cell growth kinetics.

  10. Induction of CYP1A1, CYP1A2, CYP1B1, increased oxidative stress and inflammation in the lung and liver tissues of rats exposed to incense smoke.

    PubMed

    Hussain, Tajamul; Al-Attas, Omar S; Al-Daghri, Nasser M; Mohammed, Arif A; De Rosas, Edgard; Ibrahim, Shebl; Vinodson, Benjamin; Ansari, Mohammed G; El-Din, Khaled I Alam

    2014-06-01

    Incense smoke is increasingly being recognized as a potential environmental contaminant and is linked to malignant and non-malignant respiratory diseases. The detoxification of environmental contaminants including polycyclic aromatic hydrocarbons (PAHs) involves the induction of cytochrome P-450 family enzymes (CYPs) by PAHs. However, the detoxification of PAHs also results in the generation of reactive and unstable intermediary metabolites which are implicated in the oxidative stress, DNA damage, and inflammation. It is unclear whether CYPs are similarly induced by incense smoke, which incidentally contains substantial amounts of PAHs. Here, we examined the impact of long-term incense smoke exposure on the induction of CYPs in male Wister Albino rats. Incense smoke exposure significantly induced the expression of CYP1A1, CYP1A2, and CYP1B1 mRNAs in both lung and liver tissues. The extent of CYP1A1 and CYP1B1 induction was significantly higher in the liver compared to that in the lung, while that of CYP1A2 was greater in the lung than in liver. Incense smoke exposure also increased malondialdehyde and reduced glutathione levels in lung and liver tissues, and the catalase activity in the liver tissues to significant levels. Furthermore incense smoke exposure led to a marked increase in TNF-α and IL-4 levels. The data demonstrate for the first time the capacity of incense smoke to induce CYP1 family enzymes in the target and non-target tissues. Induction of CYPs increased oxidative stress and inflammation appear to be intimately linked to promote the carcinogenesis and health complications in people chronically exposed to incense smoke.

  11. Detoxification enzyme activities (CYP1A1 and GST) in the skin of humpback whales as a function of organochlorine burdens and migration status.

    PubMed

    Bengtson Nash, S; Dawson, A; Burkhard, M; Waugh, C; Huston, W

    2014-10-01

    The activities of glutathione-s-transferase (GST) and cytochrome P-450 1A1 (CYP1A1) enzymes were measured in freshly extracted epidermis of live-biopsied, migrating, southern hemisphere humpback whales (Megaptera novaeangliae). The two quantified enzyme activities did not correlate strongly with each other. Similarly, neither correlated strongly with any of the organochlorine compound groups previously measured in the superficial blubber of the sample biopsy core, likely reflecting the anticipated low levels of typical aryl-hydrocarbon receptor ligands. GST activity did not differ significantly between genders or between northward (early migration) or southward (late migration) migrating cohorts. Indeed, the inter-individual variability in GST measurements was relatively low. This observation raises the possibility that measured activities were basal activities and that GST function was inherently impacted by the fasting state of the sampled animals, as seen in other species. These results do not support the implementation of CYP1A1 or GST as effective biomarkers of organochlorine contaminant burdens in southern hemisphere populations of humpback whales as advocated for other cetacean species. Further investigation of GST activity in feeding versus fasting cohorts may, however, provide some insight into the fasting metabolism of these behaviourally adapted populations.

  12. Specific expression of cytochrome P4501A1 gene in gill, intestine and liver of tilapia exposed to coastal sediments.

    PubMed

    Wong, C K; Yeung, H Y; Woo, P S; Wong, M H

    2001-09-01

    Toxicological effects of persistent organic pollutants (POPs) in aquatic ecosystems lead to the deterioration of water quality and adversely affect fish and human health. The highly lipophilic nature of these pollutants may enter fish through the diet or by water-borne exposure. In monitoring contamination in aquatic systems, induction of the cytochrome P450 1A1 (CYP1A1) gene of fish has been evaluated as a sensitive, "early warning" method. The objective of the present study was to characterize the induction of the gene in fish upon exposure to coastal sediments and to determine its specific expression in liver and extrahepatic organs (i.e. gill and intestine) in which the toxicological effects to the corresponding tissues could be addressed. Sediment samples were collected from different sites, including Victoria Harbour (VS), Ma Wan (MW), Tsim Bei Tsui (TBT) and Mai Po (MP). The samples were analyzed for polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). CYP1A1 mRNA expression was measured in juvenile tilapia exposed experimentally to coastal sediment for 3 and 7 days. A negative control group of fish maintained in seawater was used. Using the primer dropping polymerase chain reaction technique, gill, intestinal and hepatic CYP1A1 mRNAs were quantified. Chemical analysis shows that the samples from VS contaminated with the highest concentration of PCBs (45.24 p.p.b.) and PAHs (1663.7 p.p.b.), followed by MW (16.01 and 347.7 p.p.b.), TBT (14.48 and 235.2 p.p.b.) and MP (14.60 and 242.2 p.p.b.). Fish exposed to sediments were contaminated with various levels of PCBs (VS, 64.14-72.06 p.p.b.; MP, 27.06-31.62 p.p.b.; TBT, 27.29-33.92 p.p.b.; MW, 16.05-17.76 p.p.b.) and PAHs (VS, 124.7-304.9 p.p.b.; MP, 97.57-164.1 p.p.b.; TBT, 25.38-98 p.p.b.; MW, 24.07-68.13 p.p.b.). The control fish displayed moderate expression of CYP1A1 mRNA in liver (1.45 arbitrary units), gill (1.21 arbitrary units) and intestine (0.56 arbitrary units). Following

  13. Oxidation of the flavonoids galangin and kaempferide by human liver microsomes and CYP1A1, CYP1A2, and CYP2C9.

    PubMed

    Otake, Yoko; Walle, Thomas

    2002-02-01

    There is very limited information on cytochrome P450 (P450)-mediated oxidative metabolism of dietary flavonoids in humans. In this study, we used human liver microsomes and recombinant P450 isoforms to examine the metabolism of two flavonols, galangin and kaempferide, and one flavone, chrysin. Both galangin and kaempferide, but not chrysin, were oxidized by human liver microsomes to kaempferol, with K(m) values of 9.5 and 17.8 microM, respectively. These oxidations were catalyzed mainly by CYP1A2 but also by CYP2C9. Consistent with these observations, the human liver microsomal metabolism of galangin and kaempferide were inhibited by the P450 inhibitors furafylline and sulfaphenazole. In addition, CYP1A1, although less efficient, was also able to oxidize the two flavonols. Thus, dietary flavonols are likely to undergo oxidative metabolism mainly in the liver but also extrahepatically.

  14. Effects of 4-nitrophenol on expression of the ER-α and AhR signaling pathway-associated genes in the small intestine of rats.

    PubMed

    Tang, Juan; Song, Meiyan; Watanabe, Gen; Nagaoka, Kentaro; Rui, Xiaoli; Li, ChunMei

    2016-09-01

    4-Nitrophenol (PNP) is a persistent organic pollutant that was proven to be an environmental endocrine disruptor. The aim of this study was to evaluate the role of the estrogen receptor-α (ER-α) and aryl hydrocarbon receptor (AhR) signaling pathway in regulating the damage response to PNP in the small intestine of rats. Wistar-Imamichi male rats (21 d) were randomly divided into two groups: the control group and PNP group. Each group had three processes that were gavaged with PNP or vehicle daily: single dose (1 d), repeated dose (3 consecutive days) (3 d), and repeated dose with recovery (3 consecutive days and 3 recovery days) (6 d). The weight of the body, the related viscera, and small intestine were examined. Histological parameters of the small intestine and the quantity of mucus proteins secreted by small goblet cells were determined using HE staining and PAS staining. The mRNA expression of AhR, ER-α, CYP1A1, and GST was measured by real-time qPCR. In addition, we also analyzed the AhR, ER-α, and CYP1A1 expression in the small intestine by immunohistochemical staining. The small intestines histologically changed in the PNP-treated rat and the expression of AhR, CYP1A1, and GST was increased. While ER-α was significantly decreased in the small intestine, simultaneously, when rats were exposed to a longer PNP treatment, the damages disappeared. Our results demonstrate that PNP has an effect on the expression of AhR signaling pathway genes, AhR, CYP1A1, and GST, and ER-α in the rat small intestine.

  15. Cytochrome P450 1A1 and 1B1 in human blood lymphocytes are not suitable as biomarkers of exposure to dioxin-like compounds: polymorphisms and interindividual variation in expression and inducibility.

    PubMed

    van Duursen, Majorie B M; Sanderson, J Thomas; van den Berg, Martin

    2005-05-01

    Cytochrome P450 1A1 (CYP1A1) and 1B1 (CYP1B1) are phase I enzymes, the expression of which can be affected by many environmental compounds, including dioxins and dioxin-like compounds. Because CYP1A1 and CYP1B1 expression can easily be determined in peripheral blood lymphocytes, it is often suggested as biomarker of exposure to these compounds. In this study we investigated the interindividual differences in constitutive and induced CYP1A1-catalyzed ethoxyresorufin-O-deethylase (EROD) activity and CYP1A1 and CYP1B1 gene expression in human blood lymphocytes in a group of ten non-smoking females. Freshly isolated lymphocytes were cultured in medium containing the mitogen PHA and were exposed to the most potent dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or the less potent dioxin-like polychlorinated biphenyl 126 (PCB126). In addition, we determined the occurrence of the CYP1A1 MspI and CYP1B1 Leu432Val polymorphisms. All individuals showed a concentration-dependent increase of EROD activity by TCDD, which was significantly correlated with an increase in CYP1A1, but not CYP1B1 expression. The maximum induced EROD activity by TCDD was very different among the individuals, but the EC50 values were about the same. PCB126 also caused a concentration-dependent increase of EROD activity, but was a factor 100-1000 less potent than TCDD among the individuals. The allele frequencies for CYP1A1 MspI and CYP1B1 Leu432Val reflected a normal Caucasian population and in this study the polymorphisms had no apparent effect on the expression and activity of these enzymes. Our study shows a large interindividual variability in constitutive and induced EROD activity, and CYP1A1 and CYP1B1 expression in human lymphocytes. In addition, dioxin concentrations at which effects were observed in our in vitro study are about 10-fold higher than the human blood levels found in vivo, indicating that EROD activity and CYP1A1 and CYP1B1 expression in human lymphocytes might not be

  16. Role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to organophosphate pesticides

    SciTech Connect

    Singh, Satyender; Kumar, Vivek; Vashisht, Kapil; Singh, Priyanka; Banerjee, Basu Dev; Rautela, Rajender Singh; Grover, Shyam Sunder; Rawat, Devendra Singh; Pasha, Syed Tazeen; Jain, Sudhir Kumar; Rai, Arvind

    2011-11-15

    Organophosphate pesticides (OPs) are primarily metabolized by several xenobiotic metabolizing enzymes (XMEs). Very few studies have explored genetic polymorphisms of XMEs and their association with DNA damage in pesticide-exposed workers. The present study was designed to determine the role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to OPs. We examined 284 subjects including 150 workers occupationally exposed to OPs and 134 normal healthy controls. The DNA damage was evaluated using the alkaline comet assay and genotyping was done using PCR-RFLP. The results revealed that the PONase activity toward paraoxonase and AChE activity was found significantly lowered in workers as compared to control subjects (p < 0.001). Workers showed significantly higher DNA damage compared to control subjects (14.37 {+-} 2.15 vs. 6.24 {+-} 1.37 tail% DNA, p < 0.001). Further, the workers with CYP2D6*3 PM and PON1 (QQ and MM) genotypes were found to have significantly higher DNA damage when compared to other genotypes (p < 0.05). In addition, significant increase in DNA damage was also observed in workers with concomitant presence of certain CYP2D6 and PON1 (Q192R and L55M) genotypes which need further extensive studies. In conclusion, the results indicate that the PON1 and CYP2D6 genotypes can modulate DNA damage elicited by some OPs possibly through gene-environment interactions. -- Highlights: Black-Right-Pointing-Pointer Role of CYP1A1, CYP3A5, CYP2C, CYP2D6 and PON1 genotypes on DNA damage. Black-Right-Pointing-Pointer Workers exposed to some OPs demonstrated increased DNA damage. Black-Right-Pointing-Pointer CYP2D6 *3 PM and PON1 (Q192R and L55M) genotypes are associated with DNA damage. Black-Right-Pointing-Pointer Concomitant presence of certain CYP2D6 and PON1 genotypes can increase DNA damage.

  17. Evaluation of CYP1A1 and CYP2B1/2 m-RNA induction in rat liver slices using the NanoString technology: a novel tool for drug discovery lead optimization.

    PubMed

    Palamanda, Jairam R; Kumari, Pramila; Murgolo, Nicholas; Benbow, Larry; Lin, Xinjie; Nomeir, Amin A

    2009-08-01

    Cytochrome P450 (CYP) induction in rodents and humans is considered a liability for new chemical entities (NCEs) in drug discovery. In particular, CYP1A1 and CYP2B1/2 have been associated with the induction of liver tumors in oncogenicity studies during safety evaluation studies of potential drugs. In our laboratory, real time PCR (Taqman) has been used to quantify the induction of rat hepatic CYP1A1 and CYP2B1/2 in precision -cut rat liver slices. A novel technology that does not require m-RNA isolation or RT-PCR, (developed by NanoString Technologies) has been investigated to quantify CYP1A1 and CYP2B1/2 induction in rat liver slices. Seventeen commercially available compounds were evaluated using both Taqman and NanoString technologies. Precision-cut rat liver slices were incubated with individual compounds for 24 hr at 37 degrees C in a humidified CO(2) incubator and CYP1A1 and CYP2B1/2 m-RNA were quantified. The results from the NanoString technology were similar to those of the Taqman(R) with a high degree of correlation for both CYP isoforms (r(2)>0.85). Therefore, NanoString provides an additional new technology to evaluate the induction of CYP1A1 and 2B1/2, as well as potentially other enzymes or transporters in rat liver slices.

  18. Molecular modelling of cytochrome CYP1A1: a putative access channel explains differences in induction potency between the isomers benzo(a)pyrene and benzo(e)pyrene, and 2- and 4-acetylaminofluorene.

    PubMed

    Lewis, D F; Ioannides, C; Parke, D V

    1994-05-01

    The present studies were undertaken to provide a rationale for the observation that benzo(a)pyrene and 2-acetylaminofluorene induce the hepatic CYP1A1 protein, whereas their non-carcinogenic isomers benzo(e)pyrene and 4-acetylaminofluorene are, at best, relatively very weak inducers. Using amino acid sequence alignment, a molecular model of the CYP1A1 was constructed by analogy to CYP101, the bacterial protein for which the 3-dimensional structure is known from X-ray crystallographic analysis. The putative structure of the active site of the CYP1A1 protein shows the presence of two phenylalanine residues preferentially aligned in parallel orientation, presumably functioning as a 'sieve' for planar molecules, the established substrates of CYP1A1. The molecular dimensions of this putative access channel show a width and depth of 8.321 and 3.261 A, respectively. The width of 4-acetylaminofluorene, 8.794 A, and benzo(e)pyrene, 9.153 A, precludes their passage through this channel access in contrast to benzo(a)pyrene and 2-acetylaminofluorene having a width of 7.150 and 5.283 A, respectively, explaining their difference in CYP1A1 induction potential.

  19. CYP1A1 and CYP1B1 genetic polymorphisms, smoking and breast cancer risk in a Finnish Caucasian population.

    PubMed

    Sillanpää, Pia; Heikinheimo, Liisa; Kataja, Vesa; Eskelinen, Matti; Kosma, Veli-Matti; Uusitupa, Matti; Vainio, Harri; Metsola, Katja; Hirvonen, Ari

    2007-09-01

    We investigated the associations between two CYP1A1 polymorphisms (Ile462Val and Thr461Asn) and one CYP1B1 polymorphism (Leu432Val) and breast cancer risk. The study population consisted of 483 breast cancer patients and 482 healthy population controls, all of homogenous Finnish origin. No statistically significant overall associations were found between the CYP1A1 and CYP1B1 genotypes and breast cancer risk. However, a significant increase in the breast cancer risk was seen for women who had smoked 1-9 cigarettes/day and carried the CYP1B1 432Val allele; the OR was 2.6 (95% CI 1.07-6.46) for women carrying the Leu/Val genotype and 5.1 (95% CI 1.30-19.89, P for trend 0.005) for women with the Val/Val genotype compared to similarly smoking women homozygous for the 432Leu allele. Furthermore, when CYP1B1 genotypes were combined with the previously analyzed N-acetyl transferase (NAT2) genotypes, a significant increase in breast cancer risk was found among women who had at least one CYP1B1 432Val allele together with the NAT2 slow acetylator genotype (OR 1.52; 95% CI 1.03-2.24) compared to women carrying a combination of CYP1B1 Leu/Leu and NAT2 rapid acetylator genotypes. This risk was seen to be confined to ever smokers; the OR was 2.46 (95% CI 1.11-5.45) for ever smokers carrying at least one CYP1B1 432Val allele together with the NAT2 slow acetylator genotype compared to ever smokers with the CYP1B1 Leu/Leu and NAT2 rapid acetylator genotype combination. Our results suggest that the CYP1B1 polymorphism may be an important modifier of breast cancer risk in Finnish Caucasian women who have been exposed to tobacco smoke and/or carry the NAT2 slow acetylator genotype.

  20. Suppressive effects of estradiol on 2,3,7,8-tetrachlorodibenzo-p-dioxin-mediated transcriptional activation of murine Cyp1a-1 in mouse hepatoma Hepa 1c1c7 cells.

    PubMed

    Jeong, H G; Lee, S S

    1998-11-27

    Cultured mouse hepatoma Hepa lclc7 cells were treated with either estradiol or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or in combination to assess the role of estradiol in the process of Cypla-1 induction. Estradiol at a concentration as high as 1 microM slightly increased the activity of Cypla-1-specific 7-ethoxyresorufin O-deethylase (EROD); in contrast, TCDD-induced EROD activity and Cypla-1 mRNA levels were markedly reduced in the concomitant treatment of TCDD and estradiol in a dose-dependent manner. Treatment with tamoxifen, an anti-estrogen which acts through the estrogen receptor, did not affect the suppressive effects of estradiol on TCDD-induced EROD activity. Electrophoretic mobility shift assay using nuclear extract of cells revealed that estradiol reduced transformation of the Ah receptor to the form capable of specifically binding to an oligonucleotide containing dioxin-response element (DRE) sequence. Consistent with this, estradiol decreased TCDD-induced increased chloramphenicol acetyltransferase (CAT) activity from a DRE-containing CAT reporter plasmid after transient transfection into the cells. The levels of the cytosolic [3H]TCDD-Ah receptor complex were reduced by estradiol in competitive Ah receptor binding assay using [3H]TCDD. This study demonstrated that estradiol acts as an antagonist to TCDD and can regulate Cyp1a-1 expression in an Ah receptor-dependent manner but not through estradiol receptor in Hepa 1c1c7 cells.

  1. Docosahexaenoic acid regulates gene expression in HUVEC cells treated with polycyclic aromatic hydrocarbons.

    PubMed

    Gdula-Argasińska, Joanna; Czepiel, Jacek; Totoń-Żurańska, Justyna; Jurczyszyn, Artur; Perucki, William; Wołkow, Paweł

    2015-07-16

    The molecular mechanism of inflammation and carcinogenesis induced by exposure of polycyclic aromatic hydrocarbons (PAHs) is not clearly understood. Our study was undertaken due to the strong pro-carcinogenic potential and reactivity of PAH-metabolites, as well as the susceptibility of polyunsaturated fatty acids to oxidation. The aim of this study was to evaluate the pro- or anti-inflammatory impact of n-3 docosahexaenoic acid on human primary umbilical vein endothelial cells (HUVEC) exposed to polycyclic aromatic hydrocarbons. We analysed the influence of docosahexaenoic acid (DHA) and/or PAHs supplementation on the fatty acid profile of cell membranes, on cyclooxygenase-2 (COX-2), aryl hydrocarbon receptor (AHR), and glutathione S transferase Mu1 (GSTM1) protein expression as well as on the prostaglandin synthase 2 (PTGS2), AHR, GSTM1, PLA2G4A, and cytochrome P450 CYP1A1 gene expression. We observed that COX-2 and AHR protein expression was increased while GSTM1 expression was decreased in cells exposed to DHA and PAHs. Docosahexaenoic acid down-regulated CYP1A1 and up-regulated the AHR and PTGS2 genes. Our findings suggested that DHA contributes significantly to alleviate the harmful effects caused by PAHs in endothelial cells. Moreover, these results suggest that a diet rich in n-3 fatty acids is helpful to reduce the harmful effects of PAHs exposure on human living in heavily polluted areas.

  2. The resveratrol analogue, 2,3′,4,5′-tetramethoxystilbene, does not inhibit CYP gene expression, enzyme activity and benzo[a]pyrene–DNA adduct formation in MCF-7 cells exposed to benzo[a]pyrene

    PubMed Central

    Einem Lindeman, Tracey; Poirier, Miriam C.; Divi, Rao L.

    2011-01-01

    Exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs) induces cytochrome P450 (CYP) 1A1 and 1B1 enzymes, which biotransform PAHs resulting in the formation of DNA adducts. We hypothesised that 2,3′,4,5′-tetramethoxystilbene (TMS), an analogue of resveratrol and a potent CYP1B1 inhibitor, may inhibit r7, t8, t9-trihydroxy-c-10-(N2deoxyguanosyl)-7,8,9,10-tetrahydro-benzo[a]pyrene (BPdG) adduct formation in cells exposed to benzo[a]pyrene (BP). To address this, MCF-7 cells were cultured for 96 h in the presence of 1 μM BP, 1 μM BP + 1 μM TMS or 1 μM BP + 4 μM TMS. Cells were assayed at 2–12 h intervals for: BPdG adducts by r7, t8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE)-DNA chemiluminescence immunoassay; CYP1A1 and 1B1 gene expression changes by relative real-time polymerase chain reaction; and CYP1A1/1B1 enzyme activity by ethoxyresorufin-O-deethylase (EROD) assay. Whereas maximal BPdG levels were similar for all exposure groups, the times at which the maxima were reached increased by 16 and 24 h with the addition of 1 and 4 μM TMS, respectively. The maximal expression of CYP1A1 and CYP1B1 occurred at 16, 24 and 48 h, but the maximal level for EROD-specific activity was reached at 24, 48 and 60 h, in cells exposed to 1 μM BP, 1 μM BP + 1 μM TMS or 1 μM BP + 4 μM TMS, respectively. The area under the curve from 4 to 96 h of exposure (AUC4–96 h) for BPdG adduct formation was not increased in the presence of TMS, but for CYP1A1 and CYP1B1 expression fold increase AUC4–96 h and EROD-specific activity AUC4–96 h, there were significant (P < 0.05) increases in the presence of 4 μM TMS. Therefore, during 96 h of exposure in MCF-7 cells, the combination of BP plus TMS caused a slowing of BP biotransformation, with an increase in CYP1A1 and CYP1B1 expression and EROD activity, and a slowing, but no change in magnitude of BPdG formation. PMID:21669939

  3. Genetic association of aromatic hydrocarbon receptor (AHR) and cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) polymorphisms with dioxin blood concentrations among pregnant Japanese women.

    PubMed

    Kobayashi, Sumitaka; Sata, Fumihiro; Sasaki, Seiko; Ban, Susumu; Miyashita, Chihiro; Okada, Emiko; Limpar, Mariko; Yoshioka, Eiji; Kajiwara, Jumboku; Todaka, Takashi; Saijo, Yasuaki; Kishi, Reiko

    2013-06-07

    Dioxins are metabolized by cytochrome P450, family 1 (CYP1) via the aromatic hydrocarbon receptor (AHR). We determined whether different blood dioxin concentrations are associated with polymorphisms in AHR (dbSNP ID: rs2066853), AHR repressor (AHRR; rs2292596), CYP1 subfamily A polypeptide 1 (CYP1A1; rs4646903 and rs1048963), CYP1 subfamily A polypeptide 2 (CYP1A2; rs762551), and CYP1 subfamily B polypeptide 1 (CYP1B1; rs1056836) in pregnant Japanese women. These six polymorphisms were detected in 421 healthy pregnant Japanese women. Differences in dioxin exposure concentrations in maternal blood among the genotypes were investigated. Comparisons among the GG, GA, and AA genotypes of AHR showed a significant difference (genotype model: P=0.016 for the mono-ortho polychlorinated biphenyl concentrations and toxicity equivalence quantities [TEQs]). Second, we found a significant association with the dominant genotype model ([TT+TC] vs. CC: P=0.048 for the polychlorinated dibenzo-p-dioxin TEQs; P=0.035 for polychlorinated dibenzofuran TEQs) of CYP1A1 (rs4646903). No significant differences were found among blood dioxin concentrations and polymorphisms in AHRR, CYP1A1 (rs1048963), CYP1A2, and CYP1B1. Thus, polymorphisms in AHR and CYP1A1 (rs4646903) were associated with maternal dioxin concentrations. However, differences in blood dioxin concentrations were relatively low.

  4. Design synthesis and evaluation of the inhibitory selectivity of novel trans-resveratrol analogues on human recombinant CYP1A1 CYP1A2 and CYP1B1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of trans-stilbene derivatives containing 4’-thiomethyl substituent were synthesized and evaluated for inhibitory activities on human recombinant cytochrome P450(s): CYP1A1, CYP1A2, and CYP1B1. CYP1A2-related metabolism of stilbene derivatives was estimated by using NADPH oxidation assay. A...

  5. Inter-ethnic differences in genetic polymorphisms of xenobiotic-metabolizing enzymes (CYP1A1, CYP2D6, NAT1 and NAT2) in healthy populations: correlation with the functional in silico prediction.

    PubMed

    Khlifi, Rim; Ben Salah, Ghada; Chakroun, Amine; Hamza-Chaffai, Amel; Rebai, Ahmed

    2014-09-01

    Several studies have shown that many polymorphisms of the xenobiotic-metabolizing enzymes (XME) affect either enzymatic functions or are associated with various aspects of human health. Owing to the presence of these single nucleotide variants (SNVs), differences in detoxification capacity have been observed between many ethnicities. The aim of this investigation was to study the prevalence of four polymorphisms in XME among various ethnic groups. Attention was focused on polymorphisms of CYP2D6 (rs1058172, G>A, p.Arg365His), CYP1A1 (rs4646421, c.-26-728C>T), NAT1 (rs4921880, c.-85-1014T>A) and NAT2 (rs1208, A>G, p.Arg268Lys). These polymorphisms were analyzed in 261 healthy Tunisians individuals in comparison with different ethnic backgrounds from hapmap database. In addition, in silico functional prediction was also performed to determine the loss of function variants. Our results demonstrated that population's origins widely affect the genetic variability of XME enzymes and Tunisians show a characteristic pattern. In silico predictions showed a deleterious effect for p.Arg268Lys substitution on CYP2D6 function, findings confirmed its key role played in cancer susceptibility. These data show that detoxification genes structures depend on the studied population. This suggests that ethnic differences impact on disease risk or response to drugs and therefore should be taken into consideration in genetic association studies focusing on XME enzymes. Our results provide the first report on these SNV in Tunisian population and could be useful for further epidemiological investigations including targeted therapy.

  6. Effects of malachite green on the mRNA expression of detoxification-related genes in Nile tilapia (Oreochromis niloticus) and other major Chinese freshwater fishes.

    PubMed

    Li, Guangyu; Shen, Dan; Liang, Xu-Fang; He, Yan; He, Shan

    2013-03-01

    The use of malachite green (MG) in fish farming is prohibited in China due to its potentially toxicological and carcinogenic nature, but it is still illegally used in some places. The aim of this study was to investigate the time and concentration-dependent responses of xenobiotic metabolizing and detoxification-related genes in diverse fishes exposed to MG both in vivo and in vitro. Experimental fish were administered to two exposure groups of malachite green (MG) (0.10 and 0.50 mg L⁻¹) for 8 h. The hepatocytes isolated from Nile tilapia were incubated with MG (0.5, 1.0, and 2.0 mg L⁻¹) for 8 and 24 h, respectively. In vivo, exposure to 0.10 and 0.50 mg L⁻¹ MG for 8 h caused significant changes of the detoxification-related genes on the mRNA expression levels. Low-concentration (0.10 mg L⁻¹) level of MG induced significant increase on the mRNA expression level of GSTR gene in Nile tilapia and other fishes. The mRNA expression of grass carp UCP2 was significantly induced when exposed to 0.5 mg L⁻¹ MG. However, the mRNA expression levels of GSTA, CYP1A, and GPX were inhibited significantly by 0.5 mg L⁻¹ MG in Nile tilapia, grass carp, and Taiwan snakehead. In vitro, the significant increase of mRNA expression of these genes was detected after exposure to 0.5 mg L⁻¹ MG (UCP2), and 1.0 mg L⁻¹ MG (CYP1A1, GSTA, GSTR, and UCP2). The induction of hepatic CYP1A1, GSTA, GSTR, and UCP2 in response to MG suggested a potential role of fish CYP1A1, GSTA, GSTR, and UCP2 in MG metabolism.

  7. CpG site degeneration triggered by the loss of functional constraint created a highly polymorphic macaque drug-metabolizing gene, CYP1A2

    PubMed Central

    2011-01-01

    Background Elucidating the pattern of evolutionary changes in drug-metabolizing genes is an important subject not only for evolutionary but for biomedical research. We investigated the pattern of divergence and polymorphisms of macaque CYP1A1 and CYP1A2 genes, which are major drug-metabolizing genes in humans. In humans, CYP1A2 is specifically expressed in livers while CYP1A1 has a wider gene expression pattern in extrahepatic tissues. In contrast, macaque CYP1A2 is expressed at a much lower level than CYP1A1 in livers. Interestingly, a previous study has shown that Macaca fascicularis CYP1A2 harbored unusually high genetic diversity within species. Genomic regions showing high genetic diversity within species is occasionally interpreted as a result of balancing selection, where natural selection maintains highly diverged alleles with different functions. Nevertheless many other forces could create such signatures. Results We found that the CYP1A1/2 gene copy number and orientation has been highly conserved among mammalian genomes. The signature of gene conversion between CYP1A1 and CYP1A2 was detected, but the last gene conversion event in the simian primate lineage occurred before the Catarrhini-Platyrrhini divergence. The high genetic diversity of macaque CYP1A2 therefore cannot be explained by gene conversion between CYP1A1 and CYP1A2. By surveying CYP1A2 polymorphisms in total 91 M. fascicularis and M. mulatta, we found several null alleles segregating in these species, indicating functional constraint on CYP1A2 in macaques may have weakened after the divergence between humans and macaques. We propose that the high genetic diversity in macaque CYP1A2 is partly due to the degeneration of CpG sites, which had been maintained at a high level by purifying selection, and the rapid degeneration process was initiated by the loss of functional constraint on macaque CYP1A2. Conclusions Our findings show that the highly polymorphic CYP1A2 gene in macaques has not been

  8. Disruption of period gene expression alters the inductive effects of dioxin on the AhR signaling pathway in the mouse liver

    SciTech Connect

    Qu Xiaoyu; Metz, Richard P.; Porter, Weston W.; Cassone, Vincent M.; Earnest, David J.

    2009-02-01

    The aryl hydrocarbon receptor (AhR) and AhR nuclear translocator (ARNT) are transcription factors that express Per-Arnt-Sim (PAS) DNA-binding motifs and mediate the metabolism of drugs and environmental toxins in the liver. Because these transcription factors interact with other PAS genes in molecular feedback loops forming the mammalian circadian clockworks, we determined whether targeted disruption or siRNA inhibition of Per1 and Per2 expression alters toxin-mediated regulation of the AhR signaling pathway in the mouse liver and Hepa1c1c7 hepatoma cells in vitro. Treatment with the prototypical Ahr ligand, 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), had inductive effects on the primary targets of AhR signaling, Cyp1A1 and Cyp1B1, in the liver of all animals, but genotype-based differences were evident such that the toxin-mediated induction of Cyp1A1 expression was significantly greater (2-fold) in mice with targeted disruption of Per1 (Per1{sup ldc} and Per1{sup ldc}/Per2{sup ldc}). In vitro experiments yielded similar results demonstrating that siRNA inhibition of Per1 significantly increases the TCDD-induced expression of Cyp1A1 and Cyp1B1 in Hepa1c1c7 cells. Per2 inhibition in siRNA-infected Hepa1c1c7 cells had the opposite effect and significantly decreased both the induction of these p450 genes as well as AhR and Arnt expression in response to TCDD treatment. These findings suggest that Per1 may play a distinctive role in modulating AhR-regulated responses to TCDD in the liver.

  9. Genetic variations in the xenobiotic-metabolizing enzymes CYP1A1, CYP1A2, CYP2C9, CYP2C19 and susceptibility to colorectal cancer among Turkish people.

    PubMed

    Özhan, Gül; Mutur, Mine; Ercan, Gulcin; Alpertunga, Buket

    2014-04-01

    Cytochrome P450 (CYP) enzymes are genetically polymorphic and play key roles in the metabolism of xenobiotics. Colorectal cancer (CRC) is one of the most common malignant tumors in Turkey as well as in the world. In this study, it was aimed both to evaluate the effects of CYP variants on the susceptibility to CRC and to predict the individual response of the Turkish people to xenobiotics metabolized by CYP enzymes. For that, we assessed the association of CYP1A1, CYP1A2, CYP2C9, and CYP2C19 polymorphisms in patients with CRC in the Turkish population through a case-control study. Distributions of the variants were determined in 104 patients with CRC and 183 healthy volunteers. As results, CYP1A1 6235T/C was significantly associated with CRC risk (odds ratio [OR]=2.53; 95% confidence interval [CI]=0.99-6.45; p=0.046). In a haplotype-based analysis, CYP1A1 haplotype C6235-A2455 might be associated with the development of CRC (OR=2.70; 95% CI=0.58-5.90; p=0.046). We believe that the findings are the first results of CYP allele distributions in the Turkish population and provide an understanding of the epidemiological studies that correlate therapeutic approaches and etiology of CRC especially in Turkish patients.

  10. Ultrastructural changes, increased oxidative stress, inflammation, and altered cardiac hypertrophic gene expressions in heart tissues of rats exposed to incense smoke.

    PubMed

    Al-Attas, Omar S; Hussain, Tajamul; Ahmed, Mukhtar; Al-Daghri, Nasser; Mohammed, Arif A; De Rosas, Edgard; Gambhir, Dikshit; Sumague, Terrance S

    2015-07-01

    Incense smoke exposure has recently been linked to cardiovascular disease risk, heart rate variability, and endothelial dysfunction. To test the possible underlying mechanisms, oxidative stress, and inflammatory markers, gene expressions of cardiac hypertrophic and xenobiotic-metabolizing enzymes and ultrastructural changes were measured, respectively, using standard, ELISA-based, real-time PCR, and transmission electron microscope procedures in heart tissues of Wistar rats after chronically exposing to Arabian incense. Malondialdehyde, tumor necrosis alpha (TNF)-α, and IL-4 levels were significantly increased, while catalase and glutathione levels were significantly declined in incense smoke-exposed rats. Incense smoke exposure also resulted in a significant increase in atrial natriuretic peptide, brain natriuretic peptide, β-myosin heavy chain, CYP1A1 and CYP1A2 messenger RNAs (mRNAs). Rats exposed to incense smoke displayed marked ultrastructural changes in heart muscle with distinct cardiac hypertrophy, which correlated with the augmented hypertrophic gene expression as well as markers of cardiac damage including creatine kinase-myocardial bound (CK-MB) and lactate dehydrogenase (LDH). Increased oxidative stress, inflammation, altered cardiac hypertrophic gene expression, tissue damage, and architectural changes in the heart may collectively contribute to increased cardiovascular disease risk in individuals exposed to incense smoke. Increased gene expressions of CYP1A1 and CYP1A2 may be instrumental in the incense smoke-induced oxidative stress and inflammation. Thus, incense smoke can be considered as a potential environmental pollutant and its long-term exposure may negatively impact human health.

  11. The influence of genetic polymorphisms in Ahr, CYP1A1, CYP1A2, CYP1B1, GST M1, GST T1 and UGT1A1 on urine 1-hydroxypyrene glucuronide concentrations in healthy subjects from Rio Grande do Sul, Brazil.

    PubMed

    Abnet, Christian C; Fagundes, Renato B; Strickland, Paul T; Kamangar, Farin; Roth, Mark J; Taylor, Philip R; Dawsey, Sanford M

    2007-01-01

    Polymorphisms in genes encoding polycyclic aromatic hydrocarbon (PAH) metabolizing enzymes may alter metabolism of these carcinogens and contribute to inter-individual difference in urine concentrations. We investigated the influence of genetic polymorphism on PAH metabolism in urine from 199 healthy subjects from Southern Brazil. We measured urine 1-hydroxypyrene glucuronide (1-OHPG) concentrations using immunoaffinity chromatography and synchronous fluorescence spectroscopy and genotyped subjects using standard methods. Genetic variants in CYP1B1 (rs1056827, rs1800440, rs10012) were strongly associated with urine 1-OHPG with P-values < 0.010. Variants in aryl hydrocarbon receptor (Ahr) (rs4986826), CYP1A1 (rs1799814) and CYP1A2 (rs2069514) were also, although less strongly, associated with changes in urine 1-OHPG concentrations. These variants had P-values of 0.074, 0.040 and 0.025, respectively. The median urine 1-OHPG concentrations (pmol/ml) in the homozygous wild-type and homozygous variants for CYP1B1 (rs10012) and the Ahr, CYP1A1 and CYP1A2 variants listed above were 2.16 and 0.10, 2.16 and 0.41, 2.03 and 0.46, 2.19 and 2.79, respectively. We found no effect of deletions in GST M1 or GST T1, or different alleles of UGT1A1*28. Adjusting for age, sex, place of residence, tobacco smoke exposure, maté drinking, cachaça and barbeque preparation had only a minor impact on the associations. A model containing just exposure variables had an r2 of 0.21; a model with single genotypes for Ahr, CYP1A1, CYP1A2 and CYP1B1 had an r2 of 0.10; and a model combining both exposure and genotype information had a total r2 of 0.33. Our results suggest that CYP1B1 genotypes are strongly associated with urine 1-OHPG concentrations in this population.

  12. Functional analysis of basic transcription element (BTE)-binding protein (BTEB) 3 and BTEB4, a novel Sp1-like protein, reveals a subfamily of transcriptional repressors for the BTE site of the cytochrome P4501A1 gene promoter.

    PubMed Central

    Kaczynski, Joanna A; Conley, Abigail A; Fernandez Zapico, Martin; Delgado, Sharon M; Zhang, Jin-San; Urrutia, Raul

    2002-01-01

    The Sp1-like family of transcription factors is emerging as an integral part of the cellular machinery involved in the control of gene expression. Members of this family of proteins contain three highly homologous C-terminal zinc-finger motifs that bind GC-rich sequences found in the promoters of a diverse number of genes, such as the basic transcription element (BTE) in the promoter of the carcinogen-metabolizing cytochrome P4501A1 (CYP1A1) gene. In the present study, we report the molecular and functional characterization of BTE-binding protein (BTEB) 4, a novel ubiquitously expressed member of the Sp1-like proteins family. This protein represents a new homologue of BTEB1, originally described as a regulator of the BTE site in the CYP1A1 gene promoter. Similarly to the recently described BTEB3, we demonstrate that the N-terminal region of BTEB4 directly represses transcription and binds the co-repressor mSin3A. In addition, we show that the C-terminal zinc-finger domain of BTEB4 binds specifically the BTE site of the CYP1A1 promoter, similar to BTEB1 and BTEB3. Also, we show that both BTEB3 and BTEB4 repress the CYP1A1 gene promoter via the BTE site in HepG2 and BxPC3 cells. Thus the identification of this protein expands the repertoire of BTEB-like members of the Sp1-like protein family involved in transcriptional repression. Furthermore, our results demonstrate that the BTEB subfamily can repress the CYP1A1 gene promoter via the BTE site. PMID:12036432

  13. Diallyl sulfide induces the expression of estrogen metabolizing genes in the presence and/or absence of diethylstilbestrol in the breast of female ACI rats.

    PubMed

    Green, Mario; Newell, Oneil; Aboyade-Cole, Ayoola; Darling-Reed, Selina; Thomas, Ronald D

    2007-01-10

    Diethylstilbestrol (DES) induces mammary tumors in female ACI rats and is associated with an increased risk of developing breast cancer in humans. Diallyl sulfide (DAS) has been shown to prevent cancer in animals. Previously, we have shown that DAS inhibits the production of DES induced DNA adducts when given prior to DES. We hypothesize that DAS alters the expression of genes responsible for DES metabolism. To test this hypothesis, four groups of 10 female ACI rats were treated daily for four days as follows: (1) corn oil, (2) 50mg/kg DES, (3) 50mg/kg DAS, and (4) 50mg/kg DAS+50mg/kg DES. RNA was isolated from breast tissue and mRNA levels of CYP1A1, CYP1B1, glutathione-S-transferase (GST) and superoxide dismutase (SOD) were analyzed by real-time PCR. DES, DAS, and DES/DAS treatments increased the expression of CYP1A1 by 2.1-, 4.7-, and 12.7-fold, respectively. Similar results were seen for CYP1B1. DES decreased the expression of GST by 23%, whereas DAS and DAS/DES treatments increased the expression of GST by 12- and 16.7-fold, respectively. Similar results were seen with SOD. These results suggests that DAS may prevent the formation of DES induced DNA damage by altering the expression of DES metabolizing genes.

  14. Diversified expression of aryl hydrocarbon receptor dependent genes in human laryngeal squamous cell carcinoma cell lines treated with β-naphthoflavone.

    PubMed

    Brauze, Damian; Fijalkiewicz, Katarzyna; Szaumkessel, Marcin; Kiwerska, Katarzyna; Bednarek, Kinga; Rydzanicz, Malgorzata; Richter, Julia; Grenman, Reidar; Jarmuz-Szymczak, Malgorzata

    2014-11-18

    The aryl hydrocarbon receptor (AhR) mediates a variety of biological responses to ubiquitous environmental pollutants. In this study the effect of administration of β-naphthoflavone (BNF), potent AhR ligand, on the expression of AhR, AhRR, CYP1A1, CYP1A2, CYP1B1, NQO1, GSTA1, ALDH3A1 and UGT1A genes encoding the enzymes controlled by AhR were examined in thirteen laryngeal tumor cell lines and in HepaRG cell line. The analyzed cell lines were derived from patients with squamous laryngeal cancer, with history of cigarette smoking and without signs of human papillomavirus types 16 and 18 infection in investigated cells. Quantitative real-time RT-PCR analysis revealed huge interindividual differences in expression of genes from AhR regulatory network. Our results strongly suggest predominant effect of DNA methylation on induction of CYP1A1 expression by AhR ligands as well. Our results indicate that differentiated HepaRG cell line appeared to be very good substitute for human liver in studies on xenobiotic metabolism by AhR regulated enzymes.

  15. Nicotine and caffeine-mediated modulation in the expression of toxicant responsive genes and vesicular monoamine transporter-2 in 1-methyl 4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease phenotype in mouse.

    PubMed

    Singh, Seema; Singh, Kavita; Patel, Suman; Patel, Devendra Kumar; Singh, Chetna; Nath, Chandishwar; Singh, Mahendra Pratap

    2008-05-01

    Epidemiological evidence revealed that cigarette smokers and coffee drinkers have lower risk of Parkinson's disease (PD). Nicotine inhibits monoamine oxidase activity, and induces expression of neurotrophic factors and nicotinic acetylcholinergic receptors. However, caffeine is capable of antagonizing adenosine A(2A) receptor. Toxicant responsive enzymes and vesicular monoamine transporter-2 (VMAT-2) play critical roles in chemically induced PD. Despite some known functions, the effects of nicotine and caffeine on the expression and activity of toxicant responsive genes and on VMAT-2 are still not known. The study was therefore undertaken to investigate the effect of nicotine and caffeine on the expression and activity of toxicant responsive genes, i.e., CYP1A1, CYP2E1, GST-ya, GST-yc, GSTA4-4 and VMAT-2 in the striatum of control and MPTP-induced PD phenotype in mouse. The animals were treated intraperitoneally daily with nicotine (1 mg/kg) or caffeine (20 mg/kg) for 8 weeks, followed by 1-methyl 4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 20 mg/kg)+nicotine or caffeine for 4 weeks. MPTP significantly attenuated CYP1A1 and VMAT-2, and augmented CYP2E1, GST-ya, GST-yc and GSTA4-4 expression/activity. Nicotine or caffeine-treated animals showed significant restoration against most of the MPTP-induced alterations. The results obtained thus suggest that nicotine and caffeine modulate MPTP-induced alterations in CYP1A1, CYP2E1, GST-ya, GST-yc, GSTA4-4 and VMAT-2 expression/activity.

  16. Perinatal exposure to diesel exhaust affects gene expression in mouse cerebrum.

    PubMed

    Tsukue, Naomi; Watanabe, Manabu; Kumamoto, Takayuki; Takano, Hirohisa; Takeda, Ken

    2009-11-01

    Many environmental toxins alter reproductive function and affect the central nervous system (CNS). Gonadal steroid hormones cause differentiation of neurons and affect brain function and behavior during the perinatal period, and the CNS is thought to be particularly susceptible to toxic insult during this period. It was, therefore, hypothesized that inhalation of diesel exhaust (DE) during the fetal or suckling period would disrupt the sexual differentiation of brain function in mice, and the effects of exposure to DE during the perinatal period on sexual differentiation related gene expression of the brain were investigated. In the fetal period exposure group, pregnant ICR mice were exposed to DE from 1.5 days post-coitum (dpc) until 16 dpc. In the neonatal period exposure group, dams and their offspring were exposed to DE from the day of birth [postnatal day (PND)-0] until PND-16. Then, the cerebrums of males and females at PND-2, -5, and -16 from both groups were analyzed for expression level of mRNA encoding stress-related proteins [cytochrome P450 1A1 (CYP1A1), heme oxygenase-1 (HO-1)] and steroid hormone receptors [estrogen receptor alpha (ER alpha), estrogen receptor beta (ER beta), androgen receptor (AR)]. Expression levels of ER alpha and ER beta mRNA were increased in the cerebrum of newborns in the DE exposure groups as well as mRNA for CYP1A1 and HO-1. Results indicate that perinatal exposure to DE during the critical period of sexual differentiation of the brain may affect endocrine function.

  17. Effects of 10 cigarette smoke condensates on primary human airway epithelial cells by comparative gene and cytokine expression studies.

    PubMed

    Pickett, Gavin; Seagrave, Jeanclare; Boggs, Susan; Polzin, Gregory; Richter, Patricia; Tesfaigzi, Yohannes

    2010-03-01

    Cigarettes vary in tobacco blend, filter ventilation, additives, and other physical and chemical properties, but little is known regarding potential differences in toxicity to a smoker's airway epithelia. We compared changes in gene expression and cytokine production in primary normal human bronchial epithelial cells following treatment for 18 h with cigarette smoke condensates (CSCs) prepared from five commercial and four research cigarettes, at doses of approximately 4 microg/ml nicotine. Nine of the CSCs were produced under a standard International Organization for Standardization smoking machine regimen and one was produced by a more intense smoking machine regimen. Isolated messenger RNA (mRNA) was analyzed by microarray hybridization, and media was analyzed for secreted cytokines and chemokines. Twenty-one genes were differentially expressed by at least 9 of the 10 CSCs by more than twofold, including genes encoding detoxifying and antioxidant proteins. Cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) and NAD(P)H dehydrogenase, quinone 1 (NQO-1) were selected for validation with quantitative real-time PCR (qRT-PCR) and Western blot analyses. NQO-1 expression determined with microarrays, qRT-PCR, and Western blotting differed among the CSC types, with good correlation among the different assays. CYP1A1 mRNA levels varied substantially, but there was little correlation with the protein levels. For each CSC, the three most induced and three most repressed genes were identified. These genes may be useful as markers of exposure to that particular cigarette type. Furthermore, differences in interleukin-8 secretion were observed. These studies lay the foundation for future investigations to analyze differences in the responses of in vivo systems to tobacco products marketed with claims of reduced exposure or reduced harm.

  18. Regulation of cytochrome P4501A1 expression by hyperoxia in human lung cell lines: Implications for hyperoxic lung injury

    SciTech Connect

    Bhakta, Kushal Y. Jiang, Weiwu; Couroucli, Xanthi I.; Fazili, Inayat S.; Muthiah, Kathirvel; Moorthy, Bhagavatula

    2008-12-01

    Supplemental oxygen, used to treat pulmonary insufficiency in newborns, contributes to the development of bronchopulmonary dysplasia (BPD). Cytochrome P4501A enzymes are induced by hyperoxia in animal models, but their role in human systems is unknown. Here we investigated the molecular mechanisms of induction of CYP1A1 by hyperoxia in human lung cell lines. Three human lung cell lines were exposed to hyperoxia (95% O2) for 0-72 h, and CYP1A1 activities, apoprotein contents, and mRNA levels were determined. Hyperoxia significantly induced CYP1A1 activity and protein contents (2-4 fold), and mRNA levels (30-40 fold) over control in each cell line. Transfection of a CYP1A1 promoter/luciferase reporter construct, followed by hyperoxia (4-72 h), showed marked (2-6 fold) induction of luciferase expression. EMSA and siRNA experiments strongly suggest that the Ah receptor (AHR) is involved in the hyperoxic induction of CYP1A1. MTT reduction assays showed attenuation of cell injury with the CYP1A1 inducer beta-naphthoflavone (BNF). Our results strongly suggest that hyperoxia transcriptionally activates CYP1A1 expression in human lung cell lines by AHR-dependent mechanisms, and that CYP1A1 induction is associated with decreased toxicity. This novel finding of induction of CYP1A1 in the absence of exogenous AHR ligands could lead to novel interventions in the treatment of BPD.

  19. Constitutive expression and activity of cytochrome P450 in conventional pigs.

    PubMed

    Nielsen, Søren Drud; Bauhaus, Yvonne; Zamaratskaia, Galia; Junqueira, Matheus Antunes; Blaabjerg, Karoline; Petrat-Melin, Bjørn; Young, Jette Feveile; Rasmussen, Martin Krøyer

    2017-04-01

    Pigs have often been suggested to be a useful model for humans, when investigating CYP dependent events, like drug metabolism. However, comprehensive knowledge about the constitutive expression of the major CYP and corresponding transcription factors is limited. We compared the constitutive mRNA expression of aryl hydrocarbon receptor, constitutive androstane receptor and pregnane X receptor and CYP1A1, CYP1A2, CYP2A, CYP2E1 and CYP3A in liver, adipose tissue, muscle and small intestine in pigs, as well as the expression along the length of the small intestine and colon. Tissue samples were taken from female pigs, and analyzed for gene expression, as well as CYP dependent activity using qPCR and specific probe substrates, respectively. For all investigated transcription factors and CYPs the mRNA expression and activity was highest in the liver. CYP1A1 and CYP3A mRNA expression and activity was shown in all investigated tissues. Along the small intestine and colon the mRNA expression and activity of CYP1A1 and CYP3A was gradually decreased. The results demonstrated, similarity to that reported for humans, and hence adds to the use of pigs as a model for humans.

  20. Cytochrome P4501A1 expression, polychlorinated biphenyls and hydroxylated metabolites, and adipocyte size of bottlenose dolphins from the Southeast United States.

    PubMed

    Montie, Eric W; Fair, Patricia A; Bossart, Gregory D; Mitchum, Greg B; Houde, Magali; Muir, Derek C G; Letcher, Robert J; McFee, Wayne E; Starczak, Victoria R; Stegeman, John J; Hahn, Mark E

    2008-02-18

    Persistent organic pollutants (POPs) bioaccumulate in blubber of marine mammals. Therefore, it is important to understand the structure and dynamics of blubber layers and how they affect the accumulation of POPs and subsequent biochemical responses. We used established histological and immunohistochemical methods to document the structure of bottlenose dolphin (Tursiops truncatus) blubber and to assess the expression of cytochrome P4501A1 (CYP1A1) in skin-blubber biopsies of dolphins sampled in the waters off Charleston, SC (CHS) (N=38), and Indian River Lagoon, FL (IRL) (N=36). CYP1A1 expression was strongest and most frequent in capillary endothelial cells and was stratified in blubber; the greatest CYP1A1 staining was in the deepest layer. CYP1A1 expression in deep blubber and 2,3,7,8-TCDD Toxic Equivalents measured in the entire blubber were significantly higher in dolphins from CHS as compared to those from IRL. Adipocyte size was associated with the extent of CYP1A1 expression. Male dolphins with smaller adipocytes from CHS and IRL had higher levels of CYP1A1 expression in deep blubber. In CHS females, CYP1A1 expression in vascular endothelial cells varied with reproductive status. CYP1A1 expression in the deep layer was highest in simultaneously pregnant-lactating dolphins, and these dolphins had the smallest adipocytes in deep blubber. In all dolphins, CYP1A1 expression in the deep blubber layer was positively related to concentrations of hydroxylated PCBs (OH-PCBs) in plasma. In summary, redistribution of AHR agonists from blubber into the circulatory system may enhance PCB metabolism and production of OH-PCBs by induction of CYP1A1 in hepatocytes and, possibly, by induction of CYP1A1 in endothelial cells of the deep blubber. The OH-PCBs thus formed have the potential to interfere with thyroid hormone homeostasis.

  1. Profile of stress and toxicity gene expression in human hepatic cells treated with Efavirenz.

    PubMed

    Gomez-Sucerquia, Leysa J; Blas-Garcia, Ana; Marti-Cabrera, Miguel; Esplugues, Juan V; Apostolova, Nadezda

    2012-06-01

    Hepatic toxicity and metabolic disorders are major adverse effects elicited during the pharmacological treatment of the human immunodeficiency virus (HIV) infection. Efavirenz (EFV), the most widely used non-nucleoside reverse transcriptase inhibitor (NNRTI), has been associated with these events, with recent studies implicating it in stress responses involving mitochondrial dysfunction and oxidative stress in human hepatic cells. To expand these findings, we analyzed the influence of EFV on the expression profile of selected stress and toxicity genes in these cells. Significant up-regulation was observed with Cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1), which indicated metabolic stress. Several genes directly related to oxidative stress and damage exhibited increased expression, including Methalothionein 2A (MT2A), Heat shock 70kDa protein 6 (HSPA6), Growth differentiation factor 15 (GDF15) and DNA-damage-inducible transcript 3 (DDIT3). In addition, Early growth response protein 1 (EGR1) was enhanced, whereas mRNA levels of the inflammatory genes Chemokine (C-X-C motif) ligand 10 (CXCL10) and Serpin peptidase inhibitor (nexin, plasminogen activator inhibitor type 1), member 1 (SERPINE1) decreased and increased, respectively. This profile of gene expression supports previous data demonstrating altered mitochondrial function and presence of oxidative stress/damage in EFV-treated hepatic cells, and may be of relevance in the search for molecular targets with therapeutic potential to be employed in the prevention, diagnosis and treatment of the hepatic toxicity associated with HIV therapy.

  2. Chlorophyllin significantly reduces benzo[a]pyrene [BP]-DNA adduct formation and alters Cytochrome P450 1A1 and 1B1 expression and EROD activity in normal human mammary epithelial cells (NHMECs)

    PubMed Central

    Keshava, Channa; Divi, Rao L.; Einem, Tracey L.; Richardson, Diana L.; Leonard, Sarah L.; Keshava, Nagalakshmi; Poirier, Miriam C.; Weston, Ainsley

    2008-01-01

    We hypothesized that chlorophyllin (CHLN) would reduce BP-DNA adduct levels. Using NHMECs exposed to 4 μM BP for 24 hr in the presence or absence of 5 μM CHLN, we measured BP-DNA adducts by chemiluminescence immunoassay (CIA). The protocol included the following experimental groups: BP alone, BP given simultaneously with CHLN (BP+CHLN) for 24 hr, CHLN given for 24 hr followed by BP for 24 hr (preCHLN, postBP), and CHLN given for 48 hr with BP added for the last 24 hr (preCHLN, postBP+CHLN). Incubation with CHLN decreased BPdG levels in all groups, with 87 % inhibition in the preCHLN, postBP+CHLN group. To examine metabolic mechanisms, we monitored expression by Affymetrix microarray (U133A), and found BP-induced up-regulation of CYP1A1 and CYP1B1 expression, as well as up-regulation of groups of interferon-inducible, inflammation and signal transduction genes. Incubation of cells with CHLN and BP in any combination decreased expression of many of these genes. Using real time PCR (RT-PCR) the maximal inhibition of BP-induced gene expression, >85% for CYP1A1 and >70% for CYP1B1, was observed in the preCHLN, postBP+CHLN group. To explore the relationship between transcription and enzyme activity, the ethoxyresorufin-O-deethylase (EROD) assay was used to measure the combined CYP1A1 and CYP1B1 activities. BP exposure caused the EROD levels to double, compared to the unexposed controls. The CHLN-exposed groups all showed EROD levels similar to the unexposed controls. Therefore, the addition of CHLN to BP-exposed cells reduced BPdG formation and CYP1A1 and CYP1B1 expression, but EROD activity was not significantly reduced. PMID:19152381

  3. Cytotoxicity, genotoxicity and mechanism of action (via gene expression analysis) of the indole alkaloid aspidospermine (antiparasitic) extracted from Aspidosperma polyneuron in HepG2 cells.

    PubMed

    Coatti, Giuliana Castello; Marcarini, Juliana Cristina; Sartori, Daniele; Fidelis, Queli Cristina; Ferreira, Dalva Trevisan; Mantovani, Mário Sérgio

    2016-08-01

    Aspidospermine is an indole alkaloid with biological properties associated with combating parasites included in the genera Plasmodium, Leishmania and Trypanossoma. The present study evaluated the cytotoxicity (resazurin test), genotoxicity (comet assay) and mechanism of action (gene expression analysis via qRT-PCR) of this alkaloid in human HepG2 cells. The results demonstrated that treatment with aspidospermine was both cytotoxic (starting at 75 μM) and genotoxic (starting at 50 μM). There was no significant modulation of the expression of the following genes: GSTP1 and GPX1 (xenobiotic metabolism); CAT (oxidative stress); TP53 and CCNA2 (cell cycle); HSPA5, ERN1, EIF2AK3 and TRAF2 (endoplasmic reticulum stress); CASP8, CASP9, CASP3, CASP7, BCL-2, BCL-XL BAX and BAX (apoptosis); and PCBP4, ERCC4, OGG1, RAD21 and MLH1 (DNA repair). At a concentration of 50 μM (non-cytotoxic, but genotoxic), there was a significant increase in the expression of CYP1A1 (xenobiotic metabolism) and APC (cell cycle), and at a concentration of 100 μM, a significant increase in the expression of CYP1A1 (xenobiotic metabolism), GADD153 (endoplasmic reticulum stress) and SOD (oxidative stress) was detected, with repression of the expression of GR (xenobiotic metabolism and oxidative stress). The results of treatment with aspidospermine at a 100 μM concentration (the dose indicated in the literature to achieve 89 % reduction of the growth of L. amazonensis) suggest that increased oxidative stress and an unfolded protein response (UPR) occurred in HepG2 cells. For the therapeutic use of aspidospermine (antiparasitic), chemical alteration of the molecule to achieve a lower cytotoxicity/genotoxicity in host cells is recommended.

  4. Effect of water accommodated fraction of 0# diesel oil and crude oil on EROD activity of liver of Sparus macrocephlus and its mRNA expression.

    PubMed

    Lei, Li; Shen, Xinqiang; Jiang, Mei

    2016-12-01

    We studied the effect of water accommodated fractions (WAF) of 0# diesel and crude oil on ethoxy resorufin o-deethylase (EROD) activity and CYP1A1 mRNA expression quantity in the liver of Sparus macrocephlus. We found that there were some differences in the EROD activity and CYP1A1 mRNA induction between these two petroleum hydrocarbons. Both the EROD activity and CYP1A1 mRNA expression of fish exposed to 0# diesel WAF were higher than those of crude oil WAF fish. The EROD activities and CYP1A1 mRNA expressions in the livers 0# diesel WAF exposed group declined faster than those of crude oil WAF and the recovery of EROD activity and CYP1A1 mRNA expression in the crude oil group was higher than that of 0# diesel group.

  5. Induction of AhR-Mediated Gene Transcription by Coffee

    PubMed Central

    Ishikawa, Toshio; Takahashi, Satoshi; Morita, Koji; Okinaga, Hiroko; Teramoto, Tamio

    2014-01-01

    Background Aryl hydrocarbon receptor (AhR) is classically known to be activated by xenobiotics such as dioxins and polycyclic aromatic hydrocarbons (PAHs). Although it has been reported that PAHs are contained in roasted coffee beans, in general coffee beverages are not considered to be AhR activators. We tested whether exposure to coffee would activate AhR in cultured cells. Methods HepG2 cells stably expressing an AhR-responsive reporter gene were treated with coffee samples. Also, expression of CYP1A1, an endogenous AhR-responsive gene, was quantitated by RT-PCR and Western blotting in HepG2, Caco-2, and MCF-7 cells, after treatment with coffee. In order to obtain sensitive and reproducible results, all the experiments were performed with the cells placed in either phosphate-buffered saline (PBS) or pure serum, instead of routinely-used culture medium, whose intrinsic AhR-stimulating activity turned out to be so strong as to interfere with the analyses. Results All the coffee samples tested robustly stimulated AhR-mediated transcription in the reporter gene assays. Of note, to what extent coffee and other AhR agonists activated AhR was different, depending on whether the experiments were done in PBS or serum. CYP1A1 mRNA was induced by coffee, in HepG2, Caco-2, and MCF-7 cells placed in either PBS or serum. CYP1A1 protein expression, which was not detected in these cells incubated in PBS, was also increased by coffee in cells placed in serum. Conclusions By using culture medium-free experimental settings, we have shown that coffee is a strong AhR activator. Our observation may help elucidate as-yet-unrecognized effects of coffee on human health. PMID:25007155

  6. Suppressive effects of caraway (Carum carvi) extracts on 2, 3, 7, 8-tetrachloro-dibenzo-p-dioxin-dependent gene expression of cytochrome P450 1A1 in the rat H4IIE cells.

    PubMed

    Naderi-Kalali, B; Allameh, A; Rasaee, M J; Bach, H-J; Behechti, A; Doods, K; Kettrup, A; Schramm, K-W

    2005-04-01

    Cytochrome P450 1A1 (CYP1A1) is among the cytochrome P450 classes known to convert xenobiotics and endogenous compounds to toxic and/or carcinogenic metabolites. Suppression of CYP1A1 over expression by certain compounds is implicated in prevention of cancer caused by chemical carcinogens. Chemopreventive agents containing high levels of flavonoids and steroids-like compounds are known to suppress CYP1A1. This study was carried out for assessment of the genomic and proteomic effects of caraway (Carum carvi) extracts containing high levels of both flavonoids and steroid-like substances on ethoxy resorufin dealkylation (EROD) activity and CYP1A1 at mRNA levels. Rat hepatoma cells co-treated with a CYP1A1 inducer i.e. TCDD (2, 3, 7, 8-tetrachlorodibenzo-p-dioxin) and different preparations of caraway extracts at concentrations of 0, 0.13, 1.3, and 13 microM in culture medium. After incubation (37 degrees C and 7% CO2 for 20 h), changes in EROD specific activity recorded and compared in cells under different treatments. The results show that caraway seed extract prepared in three different organic solvents suppressed the enzyme activity in hepatoma cells in a dose-dependent manner. The extracts added above 0.13 microM could significantly inhibit EROD activity and higher levels of each extract (1.3 and 13 microM) caused approximately 10-fold suppression in the enzyme activity. Accordingly, data obtained from the RT-PCR (TaqMan) clearly showed the suppressive effects of plant extract on CYP1A1-related mRNA expression. These data clearly show that substances in caraway seeds extractable in organic solvents can potentially reverse the TCDD-dependent induction in cytochrome P450 1A1.

  7. Cytochrome P4501A1 expression in blubber biopsies of endangered false killer whales (Pseudorca crassidens) and nine other odontocete species from Hawai'i.

    PubMed

    Foltz, Kerry M; Baird, Robin W; Ylitalo, Gina M; Jensen, Brenda A

    2014-11-01

    Odontocetes (toothed whales) are considered sentinel species in the marine environment because of their high trophic position, long life spans, and blubber that accumulates lipophilic contaminants. Cytochrome P4501A1 (CYP1A1) is a biomarker of exposure and molecular effects of certain persistent organic pollutants. Immunohistochemistry was used to visualize CYP1A1 expression in blubber biopsies collected by non-lethal sampling methods from 10 species of free-ranging Hawaiian odontocetes: short-finned pilot whale, melon-headed whale, pygmy killer whale, common bottlenose dolphin, rough-toothed dolphin, pantropical spotted dolphin, Blainville's beaked whale, Cuvier's beaked whale, sperm whale, and endangered main Hawaiian Islands insular false killer whale. Significantly higher levels of CYP1A1 were observed in false killer whales and rough-toothed dolphins compared to melon-headed whales, and in general, trophic position appears to influence CYP1A1 expression patterns in particular species groups. No significant differences in CYP1A1 were found based on age class or sex across all samples. However, within male false killer whales, juveniles expressed significantly higher levels of CYP1A1 when compared to adults. Total polychlorinated biphenyl (∑PCBs) concentrations in 84% of false killer whales exceeded proposed threshold levels for health effects, and ∑PCBs correlated with CYP1A1 expression. There was no significant relationship between PCB toxic equivalent quotient and CYP1A1 expression, suggesting that this response may be influenced by agonists other than the dioxin-like PCBs measured in this study. No significant differences were found for CYP1A1 expression among social clusters of false killer whales. This work provides a foundation for future health monitoring of the endangered stock of false killer whales and other Hawaiian odontocetes.

  8. Analysis of gene expression changes of drug metabolizing enzymes in the livers of F344 rats following oral treatment with kava extract.

    PubMed

    Guo, Lei; Li, Quanzhen; Xia, Qingsu; Dial, Stacey; Chan, Po-Chuen; Fu, Peter

    2009-02-01

    The association of kava product use with liver-related risks has prompted regulatory action in many countries. We studied the changes in gene expression of drug metabolizing enzymes in the livers of Fischer 344 male rats administered kava extract by gavage for 14 weeks. Analysis of 22,226 genes revealed that there were 14, 41, 110, 386, and 916 genes significantly changed in the 0.125, 0.25, 0.5, 1.0, and 2.0 g/kg treatment groups, respectively. There were 16 drug metabolizing genes altered in all three high-dose treatment groups, among which seven genes belong to cytochrome P450 isozymes. While gene expression of Cyp1a1, 1a2, 2c6, 3a1, and 3a3 increased; Cyp 2c23 and 2c40 decreased, all in a dose-dependent manner. Real-time PCR analyses of several genes verified these results. Our results indicate that kava extract can significantly modulate drug metabolizing enzymes, particularly the CYP isozymes, which could cause herb-drug interactions and may potentially lead to hepatotoxicity.

  9. DDE and PCB 153 independently induce aryl hydrocarbon receptor (AhR) expression in peripheral blood mononuclear cells.

    PubMed

    Gaspar-Ramírez, Octavio; Pérez-Vázquez, Francisco J; Salgado-Bustamante, Mariana; González-Amaro, Roberto; Hernandez-Castro, Berenice; Pérez-Maldonado, Ivan N

    2015-01-01

    Recent studies have demonstrated that compounds inducing pro-inflammatory cytokines enhance AhR expression. The aim of this study was 2-fold: (1) to determine if two pro-inflammatory compounds, dichlorodiphenyldichloroethylene (DDE) and 2,2',4,4',5,5'-hexa-chlorobiphenyl (PCB 153), independently affect AhR gene expression in peripheral blood mononuclear cells (PBMC); and (2) if affected, to determine whether the mechanism involved was due to AhR activation or to a pro-inflammatory effect of the chemicals. PBMC isolated from healthy individuals were incubated in the presence of DDE (10 µg/ml) and PCB 153 (20 ng/ml) over time and AhR and CYP1A1 expression was assessed with a real-time PCR technique. The results indicated there was over-expression of the AhR mRNA in PBMC when the cells were treated with DDE and PCB 153. No changes in expression levels of CYP1A1 mRNA were found. Importantly, when the cells were exposed to DDE and PCB 153 in the presence of an antagonist of tumor necrosis factor (TNF)-α, the over-expression of AhR was abolished; as expected, the expression of CYP1A1 was unaffected. In conclusion, these studies demonstrated for the first time an increment of AhR expression "in vitro" in PBMC treated with two pro-inflammatory environmental pollutants, DDE and PCB153. Moreover, the over-expression of AhR was dependent of TNFα induced by DDE and PCB 153 and was independent of AhR activation.

  10. The metallohormone cadmium modulates AhR-associated gene expression in the small intestine of rats similar to ethinyl-estradiol.

    PubMed

    Kluxen, Felix M; Diel, Patrick; Höfer, Nicola; Becker, Eugenia; Degen, Gisela H

    2013-04-01

    Cadmium (Cd) affects the expression of estrogen receptor (ER) and aryl hydrocarbon receptor (AhR)-associated genes in rat uterus and elicits estrogen-like activity in vitro. The small intestine is highly exposed to dietary Cd which may mimic or antagonize estrogen action in this tissue. We investigated the effects of Cd and 17-alpha-ethinylestradiol (EE₂) on AhR-associated gene expression after oral exposure of ovariectomized female Wistar rats, and metallothionein (Mt1a) expression as a typical metal-response marker. Mt1a in the small intestine was strongly induced by co-treatment with CdCl₂ at 2 mg/kg b.wt (Cd 2) and 0.1 mg/kg b.wt EE2 than by the single compound (3-day gavage). The Cd 2-induced down-regulation of Cyp1a1, Gsta2, and Nqo1 mRNA was not antagonized by pure anti-estrogen (2.5 mg/kg b.wt ZK191703 s.c., ZK). Interestingly, the EE₂-induced down-regulation of Cyp1a1, Gsta2, and Nqo1 mRNA was antagonized by Cd 2 in vivo and in colon cancer cell lines (HT-29 and CaCo-2, treated 5 days with Cd 1 µM and/or E₂ 0.01 µM) with low or no ER-beta expression. Dose dependency was studied after Cd exposure with drinking water (5 and 50 ppm CdCl₂ equivalent to 0.4 and 4 mg/kg b.wt; Cd 0.4, Cd 4) for 28 days and EE₂ as reference. Intestinal Mt1a expression was dose dependently induced, while AhR target genes were down-regulated by Cd 0.4 similar to EE₂ and more pronounced than by Cd 4. We propose that Cd modulates intestinal AhR-associated gene expression similar to estrogens, but (contrary to its effects in uterus) via ER-independent and/or ER-beta-mediated mechanisms. Our new data suggest interference of Cd with estrogen and AhR signaling in the small intestine.

  11. Expression of the aryl hydrocarbon receptor pathway and cyclooxygenase-2 in dog tumors.

    PubMed

    Giantin, M; Vascellari, M; Lopparelli, R M; Ariani, P; Vercelli, A; Morello, E M; Cristofori, P; Granato, A; Buracco, P; Mutinelli, F; Dacasto, M

    2013-02-01

    In humans, the aryl hydrocarbon receptor (AHR) gene battery constitutes a set of contaminant-responsive genes, which have been recently shown to be involved in the regulation of several patho-physiological conditions, including tumorigenesis. As the domestic dog represents a valuable animal model in comparative oncology, mRNA levels of cytochromes P450 1A1, 1A2 and 1B1 (CYP1A1, 1A2 and 1B1), AHR, AHR nuclear translocator (ARNT), AHR repressor (AHRR, whose partial sequence was here obtained) and cyclooxygenase-2 (COX2) were measured in dog control tissues (liver, skin, mammary gland and bone), in 47 mast cell tumors (MCTs), 32 mammary tumors (MTs), 5 osteosarcoma (OSA) and related surgical margins. Target genes were constitutively expressed in the dog, confirming the available human data. Furthermore, their pattern of expression in tumor biopsies was comparable to that already described in a variety of human cancers; in particular, both AHR and COX2 genes were up-regulated and positively correlated, while CYP1A1 and CYP1A2 mRNAs were generally poorly expressed. This work demonstrated for the first time that target mRNAs are expressed in neoplastic tissues of dogs, thereby increasing the knowledge about dog cancer biology and confirming this species as an useful animal model for comparative studies on human oncology.

  12. Bcl-2 gene family expression in the brain of rat offspring after gestational and lactational dioxin exposure.

    PubMed

    Chang, Shwu-Fen; Sun, Yu-Yo; Yang, Liang-Yo; Hu, Ssu-Yao; Tsai, Shih-Ying; Lee, Wen-Sen; Lee, Yi-Hsuan

    2005-05-01

    Recent epidemiological studies have shown that dioxin, a persistent organic pollutant, is related to cognitive and behavioral abnormalities in the offspring of exposed cohort. In order to investigate the possible impact of dioxin in survival gene expression during brain development, we established an animal model of gestational and lactational dioxin-exposed rat offspring. The expressions of dioxin-responsive gene cytochrome P450 1A1 (CYP1A1), apoptotic gene Bax, and anti-apoptotic genes Bcl-2 and Bcl-xL were examined in rat liver and brains using Western blot analysis and RT-PCR. The results showed that treatment of pregnant rats with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (2 microg/kg body weight through oral delivery) at gestation day 15 resulted in an increase of Bcl-xL in offspring male liver and cerebral cortex, but a decrease in female offspring. In contrast, the expression of Bcl-xL in the cerebellum was decreased in male, but increased in female. Bcl-2, another anti-apoptotic gene, was also downregulated in P0 female liver, cerebral cortex, but was not observed in male. In the 4-month-old offspring, however, the Bcl-2 protein levels in the liver and cerebellum of both male and female pups were higher in the TCDD group as compared with the control group. However, the Bcl-2 level in the cerebral cortex of TCDD-treated groups was higher than the control group only in female but not male offspring at 4 months old. The expression of Bax showed no significant changes upon TCDD exposure at P0 stage, but was significantly reduced in the 4-month-old male cortex. These results indicate that early exposure of dioxin could affect the development of certain brain regions with gender difference, in terms of its differential effect on expressions of Bcl-xL, Bcl-2, and Bax.

  13. Preferential induction of the AhR gene battery in HepaRG cells after a single or repeated exposure to heterocyclic aromatic amines

    SciTech Connect

    Dumont, Julie Josse, Rozenn Lambert, Carine Antherieu, Sebastien Laurent, Veronique Loyer, Pascal Robin, Marie-Anne Guillouzo, Andre

    2010-11-15

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) are two of the most common heterocyclic aromatic amines (HAA) produced during cooking of meat, fish and poultry. Both HAA produce different tumor profiles in rodents and are suspected to be carcinogenic in humans. In order to better understand the molecular basis of HAA toxicity, we have analyzed gene expression profiles in the metabolically competent human HepaRG cells using pangenomic oligonucleotide microarrays, after either a single (24-h) or a repeated (28-day) exposure to 10 {mu}M PhIP or MeIQx. The most responsive genes to both HAA were downstream targets of the arylhydrocarbon receptor (AhR): CYP1A1 and CYP1A2 after both time points and CYP1B1 and ALDH3A1 after 28 days. Accordingly, CYP1A1/1A2 induction in HAA-treated HepaRG cells was prevented by chemical inhibition or small interference RNA-mediated down-regulation of the AhR. Consistently, HAA induced activity of the CYP1A1 promoter, which contains a consensus AhR-related xenobiotic-responsive element (XRE). In addition, several other genes exhibited both time-dependent and compound-specific expression changes with, however, a smaller magnitude than previously reported for the prototypical AhR target genes. These changes concerned genes mainly related to cell growth and proliferation, apoptosis, and cancer. In conclusion, these results identify the AhR gene battery as the preferential target of PhIP and MeIQx in HepaRG cells and further support the hypothesis that intake of HAA in diet might increase human cancer risk.

  14. Activation of the aryl hydrocarbon receptor pathway enhances cancer cell invasion by upregulating the MMP expression and is associated with poor prognosis in upper urinary tract urothelial cancer.

    PubMed

    Ishida, Masaru; Mikami, Shuji; Kikuchi, Eiji; Kosaka, Takeo; Miyajima, Akira; Nakagawa, Ken; Mukai, Makio; Okada, Yasunori; Oya, Mototsugu

    2010-02-01

    Aryl hydrocarbon receptor (AhR) and the activation of the AhR pathway are involved in xenobiotic-induced toxicity and carcinogenesis. Although xenobiotics, such as cigarette smoke, contribute to the development of urothelial carcinoma (UC), the relationship between AhR and UC is unclear. In the present study, we investigated AhR expression in 209 patients with upper urinary tract UC. The nuclear expression of AhR was significantly associated with histological grade, pathological T stage, lymphovascular invasion and lymph node involvement. A multivariate Cox analysis revealed that nuclear AhR expression was a significant and independent predictor for disease-specific survival (hazard ratio = 2.469, P = 0.013). To determine whether the AhR pathway can be activated in the T24 UC cell line, we examined the expression of cytochrome P450 (CYP) 1A1 and CYP1B1, which are target genes of the AhR pathway, following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a ligand of AhR. TCDD treatment upregulated the expression levels of AhR, CYP1A1 and CYP1B1. TCDD enhanced T24 cell invasion associated with the upregulation of matrix metalloproteinase (MMP)-1 and MMP-9. Furthermore, targeting AhR messenger RNA (mRNA) expression in T24 cells with small interfering RNA (siRNA) downregulated the mRNA expression of AhR, CYP1A1, CYP1B1, MMP-1, MMP-2 and MMP-9; furthermore, the cells transfected with siRNA for AhR showed decreased invasion activity in comparison with the cells transfected with a non-targeting siRNA. Our results therefore suggest that AhR plays a role in the invasiveness of UC cells and can serve as a marker for the prognosis of upper urinary tract UC.

  15. Low-dose dioxins alter gene expression related to cholesterol biosynthesis, lipogenesis, and glucose metabolism through the aryl hydrocarbon receptor-mediated pathway in mouse liver

    SciTech Connect

    Sato, Shoko; Shirakawa, Hitoshi Tomita, Shuhei; Ohsaki, Yusuke; Haketa, Keiichi; Tooi, Osamu; Santo, Noriaki; Tohkin, Masahiro; Furukawa, Yuji; Gonzalez, Frank J.; Komai, Michio

    2008-05-15

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a common environmental contaminant. TCDD binds and activates the transcription factor aryl hydrocarbon receptor (AHR), leading to adverse biological responses via the alteration of the expression of various AHR target genes. Although small amounts of TCDD are consumed via contaminated daily foodstuffs and environmental exposures, the effects of low-dose TCDD on gene expression in animal tissues have not been clarified, while a number of genes affected by high-dose TCDD were reported. In this study, we comprehensively analyzed gene expression profiles in livers of C57BL/6N mice that were orally administered relatively low doses of TCDD (5, 50, or 500 ng/kg body weight (bw) day{sup -1}) for 18 days. The hepatic TCDD concentrations, measured by gas chromatography-mass spectrometry, were 1.2, 17, and 1063 pg toxicity equivalent quantity (TEQ)/g, respectively. The mRNA level of the cytochrome P450 CYP1A1 was significantly increased by treatment with only TCDD 500 ng/kg bw day{sup -1}. DNA microarray and quantitative RT-PCR analyses revealed changes in the expression of genes involved in the circadian rhythm, cholesterol biosynthesis, fatty acid synthesis, and glucose metabolism in the liver with at all doses of TCDD employed. However, repression of expression of genes involved in energy metabolism was not observed in the livers of Ahr-null mice that were administered the same dose of TCDD. These results indicate that changes in gene expression by TCDD are mediated by AHR and that exposure to low-dose TCDD could affect energy metabolism via alterations of gene expression.

  16. 2,3,7,8-Tetrachlorodibenzo-p-dioxin-induced MUC5AC expression: aryl hydrocarbon receptor-independent/EGFR/ERK/p38-dependent SP1-based transcription.

    PubMed

    Lee, Yong C; Oslund, Karen L; Thai, Philip; Velichko, Sharlene; Fujisawa, Tomoyuki; Duong, Trang; Denison, Michael S; Wu, Reen

    2011-08-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent environmental toxicant. Epidemiological studies have associated TCDD exposure with the development of chronic obstructive pulmonary disease, which is manifested by mucous/goblet cell hyperplasia. The purpose of this research was to elucidate the pathway/mechanisms that lead to TCDD-induced gene expression in both primary normal human bronchial epithelial cells and an immortalized cell line, HBE1, under air-liquid interface conditions. TCDD exposure induced a time-dependent elevation of MUC5AC mRNA and protein synthesis, and cytochrome p450 1A1 (CYP1A1) expression in these cells. Treatment with an aryl hydrocarbon receptor antagonist had no effect on TCDD-induced MUC5AC expression, but significantly suppressed CYP1A1 induction. However, treatments with inhibitors of signaling pathways and the expression of dominant negative mutants of epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK) and p38, but not the inhibition of c-Jun N-terminal kinase pathway, abrogated MUC5AC induction, but not that of CYP1A1. These effects also occurred at the MUC5AC promoter-reporter level using the chimeric construct for a transient transfection study. Western blot analysis confirmed the phosphorylation of activated EGFR, ERK, and p38 signaling molecules, but not the c-Jun N-terminal kinase, in cells after TCDD exposure. Specificity protein 1 (Sp1) phosphorylation also occurred in cells after TCDD exposure. Both MUC5AC expression and the promoter activity were inhibited by mithramycin A, an inhibitor specific to Sp1-based transcription. These results lead to the conclusion that TCDD induced MUC5AC expression through a noncanonical aryl hydrocarbon receptor-independent, EGFR/ERK/p38-mediated signaling pathway-mediated/Sp1-based transcriptional mechanism.

  17. Endocrine disrupting effects of domestic wastewater on reproduction, sexual behavior, and gene expression in the brackish medaka Oryzias melastigma.

    PubMed

    Chen, Te-Hao; Chou, Shi-Ming; Tang, Cheng-Hao; Chen, Chia-Yang; Meng, Pei-Jie; Ko, Fung-Chi; Cheng, Jing-O

    2016-05-01

    The objective of this study was to investigate the endocrine disrupting effects of domestic wastewater on fish using the brackish medaka Oryzias melastigma as the animal model. Estuarine water samples were collected from Sihchong Creek and Baoli Creek estuaries, Taiwan, in March of 2012 to assess the whole effluent toxicity (WET) of domestic wastewater produced by the local residents and tourists. Chemical analysis detected various pharmaceuticals and personal care products (PPCPs) in the field water samples. Some of these PPCPs are endocrine disrupting chemicals. In the laboratory-based bioassay, breeding pairs were exposed to the water samples (Sihchong, Baoli, and control) for 21 days. Cumulative number of eggs spawned was significantly higher in the Sihchong group. While fish swimming activity was not affected, sexual behavior of the male fish was significantly induced in both Sihchong and Baoli groups. Male and female gonad histology was not affected. Expression level of biomarker genes CYP1A1, HSP70, and VTG was significantly induced in the Sihchong group. This study indicates that the mixture of contaminants contained in the estuarine water may cause endocrine disrupting effects in fish.

  18. Altered gene expression in HepG2 cells exposed to a methanolic coal dust extract.

    PubMed

    Guerrero-Castilla, Angelica; Olivero-Verbel, Jesus

    2014-11-01

    Exposure to coal dust has been associated with different chronic diseases and mortality risk. This airborne pollutant is produced during coal mining and transport activities, generating environmental and human toxicity. The aim of this study was to determine the effects of a coal dust methanolic extract on HepG2, a human liver hepatocellular carcinoma cell line. Cells were exposed to 5-100ppm methanolic coal extract for 12h, using DMSO as control. MTT and comet assays were used for the evaluation of cytotoxicity and genotoxicity, respectively. Real time PCR was utilized to quantify relative expression of genes related to oxidative stress, xenobiotic metabolism and DNA damage. Coal extract concentrations did not induce significant changes in HepG2 cell viability after 12h exposure; however, 50 and 100ppm of the coal extract produced a significant increase in genetic damage index with respect to negative control. Compared to vehicle control, mRNA CYP1A1 (up to 163-fold), NQO1 (up to 4.7-fold), and GADD45B (up to 4.7-fold) were up regulated, whereas PRDX1, SOD, CAT, GPX1, XPA, ERCC1 and APEX1 remained unaltered. This expression profile suggests that cells exposed to coal dust extract shows aryl hydrocarbon receptor-mediated alterations, changes in cellular oxidative status, and genotoxic effects. These findings share some similarities with those observed in liver of mice captured near coal mining areas, and add evidence that living around these industrial operations may be negatively impacting the biota and human health.

  19. INDUCTION OF CYP1A1 AD CYP1B1 AND FORMATION OF DNA ADDUCTS IN C57BL/6, BALB/C, AND F1 MICE FOLLOWING IN UTERO EXPOSURE TO 3-METHYLCHOLANTHRENE

    EPA Science Inventory

    Fetal mice are more sensitive to chemical carcinogens than are adults. Previous studies from our laboratory demonstrated differences in the mutational spectrum induced in the Ki-ras gene from lung tumors isolated from [D2 x B6D2F1]F2 mice and Balb/c mice treated in utero with 3�m...

  20. High dose of commercial products of kava (Piper methysticum) markedly enhanced hepatic cytochrome P450 1A1 mRNA expression with liver enlargement in rats.

    PubMed

    Yamazaki, Yuko; Hashida, Hiroko; Arita, Anna; Hamaguchi, Keiko; Shimura, Fumio

    2008-12-01

    Commercial products containing the kava plant (Piper methysticum), known to have the anxiolytic activity, are banned in several European countries and Canada because of the suspicion of a potential liver toxicity. In some reports, kava and kavalactones (major constituents of kava) inhibited activities of cytochrome P450 (CYP) isoforms including CYP1A2. On the other hand, a few studies showed that administration of kava to rats moderately increased CYP1A2 proteins in the liver. CYP1A isoforms are likely responsible for the metabolic activation of potent carcinogenic environmental toxins such as aflatoxins, benzo[a]pyrene, and others. On these bases, we have investigated the effects of administration of commercial kava products on gene expression of hepatic CYP1A isoforms in rats. A high dose (equivalent to approximately 380mg kavalactones/kg/day; 100 times of the suggested dosage for human use) of two different types of kava products for 8 days significantly increased liver weights. CYP1A2 mRNA expression was moderately increased (2.8-7.3 fold). More importantly, the high dose of kava markedly enhanced CYP1A1 mRNA expression (75-220 fold) as well as ethoxyresorufin O-deethylase activities and CYP1A1 immunoreactivities. Thus, no observed adverse effect levels of kavalactones would be lower than 380mg/kg/day. When the safety factor of kavalactones is assumed to be 100, a value most often used upon the risk analysis of chemicals and designed to account for interspecies and intraspecies variations, a number of kava product users likely ingest more kavalactones than acceptable daily intakes. Based on overall evidence, we should pay considerable attention to the possibility that kava products induce hepatic CYP1A1 expression in human especially in sensitive individuals.

  1. Quantification of phase I / II metabolizing enzyme gene expression and polycyclic aromatic hydrocarbon-DNA adduct levels in human prostate

    PubMed Central

    John, Kaarthik; Ragavan, Narasimhan; Pratt, M. Margaret; Singh, Paras B.; Al-Buheissi, Salah; Matanhelia, Shyam S.; Phillips, David H.; Poirier, Miriam C.; Martin, Francis L.

    2008-01-01

    BACKGROUND Studies of migrant populations suggest that dietary and/or environmental factors play a crucial role in the aetiology of prostatic adenocarcinoma (CaP). The human prostate consists of the peripheral zone (PZ), transition zone (TZ) and central zone (CZ); CaP occurs most often in the PZ. METHODS To investigate the notion that an underlying differential expression of phase I/II genes, and/or the presence of polycyclic aromatic hydrocarbon (PAH)-DNA adducts might explain the elevated PZ susceptibility, we examined prostate tissues (matched tissue sets consisting of PZ and TZ) from men undergoing radical retropubic prostatectomy for CaP (n=26) or cystoprostatectomy (n=1). Quantitative gene expression analysis was employed for cytochrome P450 (CYP) isoforms CYP1A1, CYP1B1 and CYP1A2, as well as N-acetyltransferase 1 and 2 (NAT1 and NAT2) and catechol-O-methyl transferase (COMT). RESULTS CYP1B1, NAT1 and COMT were expressed in all tissue sets; levels of CYP1B1 and NAT1 were consistently higher in the PZ compared to TZ. Immunohistochemistry confirmed the presence of CYP1B1 (nuclear-associated and primarily in basal epithelial cells) and NAT1. Tissue sections from 23 of these aforementioned 27 matched tissue sets were analyzed for PAH-DNA adduct levels using antiserum elicited against DNA modified with r7, t8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydro-benzo[a]pyrene (BPDE). PAH-DNA adduct levels were highest in glandular epithelial cells, but a comparison of PZ and TZ showed no significant differences. CONCLUSION Although expression of activating and/or detoxifying enzymes may be higher in the PZ, PAH-DNA adduct levels appear to be similar in both zones. Therefore, factors other than PAH-DNA adducts may be responsible for promotion of tumour formation in the human prostate. PMID:19143007

  2. Chlorophyllin significantly reduces benzo[a]pyrene-DNA adduct formation and alters cytochrome P450 1A1 and 1B1 expression and EROD activity in normal human mammary epithelial cells.

    PubMed

    Keshava, Channa; Divi, Rao L; Einem, Tracey L; Richardson, Diana L; Leonard, Sarah L; Keshava, Nagalakshmi; Poirier, Miriam C; Weston, Ainsley

    2009-03-01

    We hypothesized that chlorophyllin (CHLN) would reduce benzo[a]pyrene-DNA (BP-DNA) adduct levels. Using normal human mammary epithelial cells (NHMECs) exposed to 4 microM BP for 24 hr in the presence or absence of 5 microM CHLN, we measured BP-DNA adducts by chemiluminescence immunoassay (CIA). The protocol included the following experimental groups: BP alone, BP given simultaneously with CHLN (BP+CHLN) for 24 hr, CHLN given for 24 hr followed by BP for 24 hr (preCHLN, postBP), and CHLN given for 48 hr with BP added for the last 24 hr (preCHLN, postBP+CHLN). Incubation with CHLN decreased BPdG levels in all groups, with 87% inhibition in the preCHLN, postBP+CHLN group. To examine metabolic mechanisms, we monitored expression by Affymetrix microarray (U133A), and found BP-induced up-regulation of CYP1A1 and CYP1B1 expression, as well as up-regulation of groups of interferon-inducible, inflammation and signal transduction genes. Incubation of cells with CHLN and BP in any combination decreased expression of many of these genes. Using reverse transcription real time PCR (RT-PCR) the maximal inhibition of BP-induced gene expression, >85% for CYP1A1 and >70% for CYP1B1, was observed in the preCHLN, postBP+CHLN group. To explore the relationship between transcription and enzyme activity, the ethoxyresorufin-O-deethylase (EROD) assay was used to measure the combined CYP1A1 and CYP1B1 activities. BP exposure caused the EROD levels to double, when compared with the unexposed controls. The CHLN-exposed groups all showed EROD levels similar to the unexposed controls. Therefore, the addition of CHLN to BP-exposed cells reduced BPdG formation and CYP1A1 and CYP1B1 expression, but EROD activity was not significantly reduced.

  3. Human bronchial epithelial cells exposed in vitro to diesel exhaust particles exhibit alterations in cell rheology and cytotoxicity associated with decrease in antioxidant defenses and imbalance in pro- and anti-apoptotic gene expression.

    PubMed

    Seriani, Robson; de Souza, Claudia Emanuele Carvalho; Krempel, Paloma Gava; Frias, Daniela Perroni; Matsuda, Monique; Correia, Aristides Tadeu; Ferreira, Márcia Zotti Justo; Alencar, Adriano Mesquita; Negri, Elnara Marcia; Saldiva, Paulo Hilário Nascimento; Mauad, Thais; Macchione, Mariangela

    2016-05-01

    Diesel exhaust particles (DEPs) from diesel engines produce adverse alterations in cells of the airways by activating intracellular signaling pathways and apoptotic gene overexpression, and also by influencing metabolism and cytoskeleton changes. This study used human bronchial epithelium cells (BEAS-2B) in culture and evaluates their exposure to DEPs (15ug/mL for 1 and 2 h) in order to determine changes to cell rheology (viscoelasticity) and gene expression of the enzymes involved in oxidative stress, apoptosis, and cytotoxicity. BEAS-2B cells exposed to DEPs were found to have a significant loss in stiffness, membrane stability, and mitochondrial activity. The genes involved in apoptosis [B cell lymphoma 2 (BCL-2 and caspase-3)] presented inversely proportional expressions (p = 0.05, p = 0.01, respectively), low expression of the genes involved in antioxidant responses [SOD1 (superoxide dismutase 1); SOD2 (superoxide dismutase 2), and GPx (glutathione peroxidase) (p = 0.01)], along with an increase in cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) (p = 0.01). These results suggest that alterations in cell rheology and cytotoxicity could be associated with oxidative stress and imbalance between pro- and anti-apoptotic genes.

  4. Gene expression and pathologic alterations in juvenile rainbow trout due to chronic dietary TCDD exposure.

    PubMed

    Liu, Qing; Rise, Matthew L; Spitsbergen, Jan M; Hori, Tiago S; Mieritz, Mark; Geis, Steven; McGraw, Joseph E; Goetz, Giles; Larson, Jeremy; Hutz, Reinhold J; Carvan, Michael J

    2013-09-15

    The goal of this project was to use functional genomic methods to identify molecular biomarkers as indicators of the impact of TCDD exposure in rainbow trout. Specifically, we investigated the effects of chronic dietary TCDD exposure on whole juvenile rainbow trout global gene expression associated with histopathological analysis. Juvenile rainbow trout were fed Biodiet starter with TCDD added at 0, 0.1, 1, 10 and 100 ppb (ngTCDD/g food), and fish were sampled from each group at 7, 14, 28 and 42 days after initiation of feeding. 100 ppb TCDD caused 100% mortality at 39 days. Fish fed with 100 ppb TCDD food had TCDD accumulation of 47.37 ppb (ngTCDD/g fish) in whole fish at 28 days. Histological analysis from TCDD-treated trout sampled from 28 and 42 days revealed that obvious lesions were found in skin, oropharynx, liver, gas bladder, intestine, pancreas, nose and kidney. In addition, TCDD caused anemia in peripheral blood, decreases in abdominal fat, increases of remodeling of fin rays, edema in pericardium and retrobulbar hemorrhage in the 100 ppb TCDD-treated rainbow trout compared to the control group at 28 days. Dose- and time-dependent global gene expression analyses were performed using the cGRASP 16,000 (16K) cDNA microarray. TCDD-responsive whole body transcripts identified in the microarray experiments have putative functions involved in various biological processes including growth, cell proliferation, metabolic process, and immune system processes. Nine microarray-identified genes were selected for QPCR validation. CYP1A3 and CYP1A1 were common up-regulated genes and HBB1 was a common down-regulated gene among each group based on microarray data, and their QPCR validations are consistent with microarray data for the 10 and 100 ppb TCDD treatment groups after 28 days exposure (p<0.05). In addition, in the 100 ppb group at 28 days, expression of complement component C3-1 and trypsin-1 precursor have a more than 10-fold induction from the microarray

  5. Gene expression profiling of porcine mammary epithelial cells after challenge with Escherichia coli and Staphylococcus aureus in vitro.

    PubMed

    Jaeger, Alexandra; Bardehle, Danilo; Oster, Michael; Günther, Juliane; Muráni, Eduard; Ponsuksili, Siriluck; Wimmers, Klaus; Kemper, Nicole

    2015-05-06

    Postpartum Dysgalactia Syndrome (PDS) represents a considerable health problem of postpartum sows, primarily indicated by mastitis and lactation failure. The poorly understood etiology of this multifactorial disease necessitates the use of the porcine mammary epithelial cell (PMEC) model to identify how and to what extent molecular pathogen defense mechanisms prevent bacterial infections at the first cellular barrier of the gland. PMEC were isolated from three lactating sows and challenged with heat-inactivated potential mastitis-causing pathogens Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) for 3 h and 24 h, in vitro. We focused on differential gene expression patterns of PMEC after pathogen challenge in comparison with the untreated control by performing microarray analysis. Our results show that a core innate immune response of PMEC is partly shared by E. coli and S. aureus. But E. coli infection induces much faster and stronger inflammatory response than S. aureus infection. An immediate and strong up-regulation of genes encoding cytokines (IL1A and IL8), chemokines (CCL2, CXCL1, CXCL2, CXCL3, and CXCL6) and cell adhesion molecules (VCAM1, ICAM1, and ITGB3) was explicitly obvious post-challenge with E. coli inducing a rapid recruitment and activation of cells of host defense mediated by IL1B and TNF signaling. In contrast, S. aureus infection rather induces the expression of genes encoding monooxygenases (CYP1A1, CYP3A4, and CYP1B1) initiating processes of detoxification and pathogen elimination. The results indicate that the course of PDS depends on the host recognition of different structural and pathogenic profiles first, which critically determines the extent and effectiveness of cellular immune defense after infection.

  6. Method of controlling gene expression

    DOEpatents

    Peters, Norman K.; Frost, John W.; Long, Sharon R.

    1991-12-03

    A method of controlling expression of a DNA segment under the control of a nod gene promoter which comprises administering to a host containing a nod gene promoter an amount sufficient to control expression of the DNA segment of a compound of the formula: ##STR1## in which each R is independently H or OH, is described.

  7. The flow of gene expression.

    PubMed

    Misteli, Tom

    2004-03-01

    Gene expression is a highly interconnected multistep process. A recent meeting in Iguazu Falls, Argentina, highlighted the need to uncover both the molecular details of each single step as well as the mechanisms of coordination among processes in order to fully understand the expression of genes.

  8. Discovering modulators of gene expression

    PubMed Central

    Babur, Özgün; Demir, Emek; Gönen, Mithat; Sander, Chris; Dogrusoz, Ugur

    2010-01-01

    Proteins that modulate the activity of transcription factors, often called modulators, play a critical role in creating tissue- and context-specific gene expression responses to the signals cells receive. GEM (Gene Expression Modulation) is a probabilistic framework that predicts modulators, their affected targets and mode of action by combining gene expression profiles, protein–protein interactions and transcription factor–target relationships. Using GEM, we correctly predicted a significant number of androgen receptor modulators and observed that most modulators can both act as co-activators and co-repressors for different target genes. PMID:20466809

  9. Health risk assessment for air pollutants: alterations in lung and cardiac gene expression in mice exposed to Milano winter fine particulate matter (PM2.5).

    PubMed

    Sancini, Giulio; Farina, Francesca; Battaglia, Cristina; Cifola, Ingrid; Mangano, Eleonora; Mantecca, Paride; Camatini, Marina; Palestini, Paola

    2014-01-01

    Oxidative stress, pulmonary and systemic inflammation, endothelial cell dysfunction, atherosclerosis and cardiac autonomic dysfunction have been linked to urban particulate matter exposure. The chemical composition of airborne pollutants in Milano is similar to those of other European cities though with a higher PM2.5 fraction. Milano winter fine particles (PM2.5win) are characterized by the presence of nitrate, organic carbon fraction, with high amount of polycyclic aromatic hydrocarbons and elements such as Pb, Al, Zn, V, Fe, Cr and others, with a negligible endotoxin presence. In BALB/c mice, we examined, at biochemical and transcriptomic levels, the adverse effects of repeated Milano PM2.5win exposure in lung and heart. We found that ET-1, Hsp70, Cyp1A1, Cyp1B1 and Hsp-70, HO-1, MPO respectively increased within lung and heart of PM2.5win-treated mice. The PM2.5win exposure had a strong impact on global gene expression of heart tissue (181 up-regulated and 178 down-regulated genes) but a lesser impact on lung tissue (14 up-regulated genes and 43 down-regulated genes). Focusing on modulated genes, in lung we found two- to three-fold changes of those genes related to polycyclic aromatic hydrocarbons exposure and calcium signalling. Within heart the most striking aspect is the twofold to threefold increase in collagen and laminin related genes as well as in genes involved in calcium signaling. The current study extends our previous findings, showing that repeated instillations of PM2.5win trigger systemic adverse effects. PM2.5win thus likely poses an acute threat primarily to susceptible people, such as the elderly and those with unrecognized coronary artery or structural heart disease. The study of genomic responses will improve understanding of disease mechanisms and enable future clinical testing of interventions against the toxic effects of air pollutant.

  10. Human Lacrimal Gland Gene Expression

    PubMed Central

    Aakalu, Vinay Kumar; Parameswaran, Sowmya; Maienschein-Cline, Mark; Bahroos, Neil; Shah, Dhara; Ali, Marwan; Krishnakumar, Subramanian

    2017-01-01

    Background The study of human lacrimal gland biology and development is limited. Lacrimal gland tissue is damaged or poorly functional in a number of disease states including dry eye disease. Development of cell based therapies for lacrimal gland diseases requires a better understanding of the gene expression and signaling pathways in lacrimal gland. Differential gene expression analysis between lacrimal gland and other embryologically similar tissues may be helpful in furthering our understanding of lacrimal gland development. Methods We performed global gene expression analysis of human lacrimal gland tissue using Affymetrix ® gene expression arrays. Primary data from our laboratory was compared with datasets available in the NLM GEO database for other surface ectodermal tissues including salivary gland, skin, conjunctiva and corneal epithelium. Results The analysis revealed statistically significant difference in the gene expression of lacrimal gland tissue compared to other ectodermal tissues. The lacrimal gland specific, cell surface secretory protein encoding genes and critical signaling pathways which distinguish lacrimal gland from other ectodermal tissues are described. Conclusions Differential gene expression in human lacrimal gland compared with other ectodermal tissue types revealed interesting patterns which may serve as the basis for future studies in directed differentiation among other areas. PMID:28081151

  11. Stimulatory effect of sesamin on hepatic cytochrome P450 activities in Atlantic salmon (Salmo salar L.) is not directly associated with expression of genes related to xenobiotic metabolism.

    PubMed

    Zlabek, Vladimir; Vestergren, AnnaLotta Schiller; Trattner, Sofia; Wagner, Liane; Pickova, Jana; Zamaratskaia, Galia

    2015-01-01

    1. This study examined hepatic cytochrome P450 (CYP450) response to dietary sesamin in combination with different n-6/n-3 fatty acid ratios in fish diet. Over a period of 4 months, fish were fed seven different experimental diets an n-6/n-3 FA ratio of either 0.5 or 1.0 in combination with two sesamin levels: low sesamin = 1.16 g/kg feed and high sesamin = 5.8 g/kg feed. Control diets did not contain sesamin. 2. The CYP450-associated activities of ethoxyresorufin O-deethylase (EROD), 7-benzyloxy-4-trifluoromethylcoumarin O-debenzylation (BFCOD), pentoxyresorufin O-depentylase (PROD), coumarin hydroxylase (COH), methoxyresorufin O-deethylase (MROD) and p-nitrophenol hydroxylase (PNPH) were significantly induced by dietary sesamin in a dose-related manner. 3. Expressions of the genes CYP1A1, CYP1A3, CYP3A, AhR1α, AhR2β, AhR2δ and PXR involved in the regulation of CYP450 activities, was not the primary source of this induction.

  12. Differential Expression of Cytochrome P450 Enzymes in Normal and Tumor Tissues from Childhood Rhabdomyosarcoma

    PubMed Central

    Molina-Ortiz, Dora; Camacho-Carranza, Rafael; González-Zamora, José Francisco; Shalkow-Kalincovstein, Jaime; Cárdenas-Cardós, Rocío; Ností-Palacios, Rosario; Vences-Mejía, Araceli

    2014-01-01

    Intratumoral expression of genes encoding Cytochrome P450 enzymes (CYP) might play a critical role not only in cancer development but also in the metabolism of anticancer drugs. The purpose of this study was to compare the mRNA expression patterns of seven representative CYPs in paired tumor and normal tissue of child patients with rabdomyosarcoma (RMS). Using real time quantitative RT-PCR, the gene expression pattern of CYP1A1, CYP1A2, CYP1B1, CYP2E1, CYP2W1, CYP3A4, and CYP3A5 were analyzed in tumor and adjacent non-tumor tissues from 13 child RMS patients. Protein concentration of CYPs was determined using Western blot. The expression levels were tested for correlation with the clinical and pathological data of the patients. Our data showed that the expression levels of CYP1A1 and CYP1A2 were negligible. Elevated expression of CYP1B1 mRNA and protein was detected in most RMS tumors and adjacent normal tissues. Most cancerous samples exhibit higher levels of both CYP3A4 and CYP3A5 compared with normal tissue samples. Expression of CYP2E1 mRNA was found to be significantly higher in tumor tissue, however no relation was found with protein levels. CYP2W1 mRNA and/or protein are mainly expressed in tumors. In conclusion, we defined the CYP gene expression profile in tumor and paired normal tissue of child patients with RMS. The overexpression of CYP2W1, CYP3A4 and CYP3A5 in tumor tissues suggests that they may be involved in RMS chemoresistance; furthermore, they may be exploited for the localized activation of anticancer prodrugs. PMID:24699256

  13. Transgenic rice plants expressing human p450 genes involved in xenobiotic metabolism for phytoremediation.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2008-01-01

    Phytoremediation is the use of plants to remove xenobiotic compounds from the environment. Plants have the inherent ability to detoxify xenobiotic pollutants, but they are generally poor at degrading them. The introduction of genes involved in xenobiotic degradation is aimed at enhancing plants' potential further. Rice (Oryza sativa) is a good candidate for this purpose and has been transformed with genes encoding cytochrome P450 monooxygenases CYP1A1, CYP2B6, and CYP2C19. The transgenic plants were more tolerant to various herbicides than nontransgenic Nipponbare rice plants, owing to enhanced metabolism by the introduced P450 enzymes. Transgenic plants were able to remove atrazine and metolachlor from soil. Field testing and risk assessment are very important for developing transgenic plants for phytoremediation. Transgenic rice plants should become useful as herbicide-tolerant crops and for phytoremediation of xenobiotic pollutants in future.

  14. Monoallelic Gene Expression in Mammals.

    PubMed

    Chess, Andrew

    2016-11-23

    Monoallelic expression not due to cis-regulatory sequence polymorphism poses an intriguing problem in epigenetics because it requires the unequal treatment of two segments of DNA that are present in the same nucleus and that can indeed have absolutely identical sequences. Here, I focus on a few recent developments in the field of monoallelic expression that are of particular interest and raise interesting questions for future work. One development is regarding analyses of imprinted genes, in which recent work suggests the possibility that intriguing networks of imprinted genes exist and are important for genetic and physiological studies. Another issue that has been raised in recent years by a number of publications is the question of how skewed allelic expression should be for it to be designated as monoallelic expression and, further, what methods are appropriate or inappropriate for analyzing genomic data to examine allele-specific expression. Perhaps the most exciting recent development in mammalian monoallelic expression is a clever and carefully executed analysis of genetic diversity of autosomal genes subject to random monoallelic expression (RMAE), which provides compelling evidence for distinct evolutionary forces acting on random monoallelically expressed genes.

  15. Tuning noise in gene expression.

    PubMed

    Tyagi, Sanjay

    2015-05-05

    The relative contribution of promoter architecture and the associated chromatin environment in regulating gene expression noise has remained elusive. In their recent work, Arkin, Schaffer and colleagues (Dey et al, 2015) show that mean expression and noise for a given promoter at different genomic loci are uncorrelated and influenced by the local chromatin environment.

  16. Differential Gene Expression in Glaucoma

    PubMed Central

    Jakobs, Tatjana C.

    2014-01-01

    In glaucoma, regardless of its etiology, retinal ganglion cells degenerate and eventually die. Although age and elevated intraocular pressure (IOP) are the main risk factors, there are still many mysteries in the pathogenesis of glaucoma. The advent of genome-wide microarray expression screening together with the availability of animal models of the disease has allowed analysis of differential gene expression in all parts of the eye in glaucoma. This review will outline the findings of recent genome-wide expression studies and discuss their commonalities and differences. A common finding was the differential regulation of genes involved in inflammation and immunity, including the complement system and the cytokines transforming growth factor β (TGFβ) and tumor necrosis factor α (TNFα). Other genes of interest have roles in the extracellular matrix, cell–matrix interactions and adhesion, the cell cycle, and the endothelin system. PMID:24985133

  17. Differential gene expression in glaucoma.

    PubMed

    Jakobs, Tatjana C

    2014-07-01

    In glaucoma, regardless of its etiology, retinal ganglion cells degenerate and eventually die. Although age and elevated intraocular pressure (IOP) are the main risk factors, there are still many mysteries in the pathogenesis of glaucoma. The advent of genome-wide microarray expression screening together with the availability of animal models of the disease has allowed analysis of differential gene expression in all parts of the eye in glaucoma. This review will outline the findings of recent genome-wide expression studies and discuss their commonalities and differences. A common finding was the differential regulation of genes involved in inflammation and immunity, including the complement system and the cytokines transforming growth factor β (TGFβ) and tumor necrosis factor α (TNFα). Other genes of interest have roles in the extracellular matrix, cell-matrix interactions and adhesion, the cell cycle, and the endothelin system.

  18. Transgenic Arabidopsis Gene Expression System

    NASA Technical Reports Server (NTRS)

    Ferl, Robert; Paul, Anna-Lisa

    2009-01-01

    The Transgenic Arabidopsis Gene Expression System (TAGES) investigation is one in a pair of investigations that use the Advanced Biological Research System (ABRS) facility. TAGES uses Arabidopsis thaliana, thale cress, with sensor promoter-reporter gene constructs that render the plants as biomonitors (an organism used to determine the quality of the surrounding environment) of their environment using real-time nondestructive Green Fluorescent Protein (GFP) imagery and traditional postflight analyses.

  19. Zipf's Law in Gene Expression

    NASA Astrophysics Data System (ADS)

    Furusawa, Chikara; Kaneko, Kunihiko

    2003-02-01

    Using data from gene expression databases on various organisms and tissues, including yeast, nematodes, human normal and cancer tissues, and embryonic stem cells, we found that the abundances of expressed genes exhibit a power-law distribution with an exponent close to -1; i.e., they obey Zipf’s law. Furthermore, by simulations of a simple model with an intracellular reaction network, we found that Zipf’s law of chemical abundance is a universal feature of cells where such a network optimizes the efficiency and faithfulness of self-reproduction. These findings provide novel insights into the nature of the organization of reaction dynamics in living cells.

  20. Stress-related gene expression changes in rainbow trout hepatocytes exposed to various municipal wastewater treatment influents and effluents.

    PubMed

    Gagné, F; Smyth, S A; André, C; Douville, M; Gélinas, M; Barclay, K

    2013-03-01

    The present study sought to examine the performance of six different wastewater treatment processes from 12 wastewater treatment plants using a toxicogenomic approach in rainbow trout hepatocytes. Freshly prepared rainbow trout hepatocytes were exposed to increasing concentrations of influent (untreated wastewaters) and effluent (C(18)) extracts for 48 h at 15 °C. A test battery of eight genes was selected to track changes in xenobiotic biotransformation, estrogenicity, heavy metal detoxification, and oxidative stress. The wastewaters were processed by six different treatment systems: facultative and aerated lagoons, activated sludge, biological aerated filter, biological nutrient removal, chemically assisted primary treated, and trickling filter/solids contact. Based on the chemical characteristics of the effluents, the treatment plants were generally effective in removing total suspended solids and chemical oxygen demand, but less so for ammonia and alkalinity. The 12 influents differed markedly with each other, which makes the comparison among treatment processes difficult. For the influents, both population size and flow rate influenced the increase in the following mRNA levels in exposed hepatocytes: metallothionein (MT), cytochrome P4503A4 (CYP3A4), and vitellogenin (VTG). Gene expression of glutathione S-transferase (GST) and the estrogen receptor (ER), were influenced only by population size in exposed cells to the influent extracts. The remaining genes-superoxide dismutase (SOD) and multidrug resistance transporter (MDR)-were not influenced by either population size or flow rate in exposed cells. It is noteworthy that the changes in MT, ER, and VTG in cells exposed to the effluents were significantly affected by the influents across the 12 cities examined. However, SOD, CYP1A1, CYP3A4, GST, and MDR gene expression were the least influenced by the incoming influents. The data also suggest that wastewater treatments involving biological or aeration

  1. Neighboring Genes Show Correlated Evolution in Gene Expression.

    PubMed

    Ghanbarian, Avazeh T; Hurst, Laurence D

    2015-07-01

    When considering the evolution of a gene's expression profile, we commonly assume that this is unaffected by its genomic neighborhood. This is, however, in contrast to what we know about the lack of autonomy between neighboring genes in gene expression profiles in extant taxa. Indeed, in all eukaryotic genomes genes of similar expression-profile tend to cluster, reflecting chromatin level dynamics. Does it follow that if a gene increases expression in a particular lineage then the genomic neighbors will also increase in their expression or is gene expression evolution autonomous? To address this here we consider evolution of human gene expression since the human-chimp common ancestor, allowing for both variation in estimation of current expression level and error in Bayesian estimation of the ancestral state. We find that in all tissues and both sexes, the change in gene expression of a focal gene on average predicts the change in gene expression of neighbors. The effect is highly pronounced in the immediate vicinity (<100 kb) but extends much further. Sex-specific expression change is also genomically clustered. As genes increasing their expression in humans tend to avoid nuclear lamina domains and be enriched for the gene activator 5-hydroxymethylcytosine, we conclude that, most probably owing to chromatin level control of gene expression, a change in gene expression of one gene likely affects the expression evolution of neighbors, what we term expression piggybacking, an analog of hitchhiking.

  2. Long-term estrogen exposure promotes carcinogen bioactivation, induces persistent changes in gene expression, and enhances the tumorigenicity of MCF-7 human breast cancer cells

    SciTech Connect

    Spink, Barbara C.; Bennett, James A.; Pentecost, Brian T.; Lostritto, Nicole; Englert, Neal A.; Benn, Geoffrey K.; Goodenough, Angela K.; Turesky, Robert J.; Spink, David C.

    2009-11-01

    The cumulative exposure to estrogens is an important determinant in the risk of breast cancer, yet the full range of mechanisms involving estrogens in the genesis and progression of breast cancer remains a subject of debate. Interactions of estrogens and environmental toxicants have received attention as putative factors contributing to carcinogenesis. Mechanistic studies have demonstrated interactions between estrogen receptor alpha (ERalpha) and the aryl hydrocarbon receptor (AhR), with consequences on the genes that they regulate. Many studies of ERalpha and AhR-mediated effects and crosstalk between them have focused on the initial molecular events. In this study, we investigated ERalpha- and AhR-mediated effects in long-term estrogen exposed (LTEE) MCF-7 human breast cancer cells, which were obtained by continuous culturing for at least 12 weeks in medium supplemented with 1 nM of 17beta-estradiol (E{sub 2}). With these LTEE cells and with parallel control cells cultured without E{sub 2} supplementation, we performed an extensive study of cytochrome P450 (CYP) induction, carcinogen bioactivation, global gene expression, and tumorigenicity in immunocompromised mice. We found that LTEE cells, in comparison with control cells, had higher levels of AhR mRNA and protein, greater responsiveness for AhR-regulated CYP1A1 and CYP1B1 induction, a 6-fold higher initial level of benzo(a)pyrene-DNA adducts as determined by liquid chromatography tandem mass spectrometry, marked differences in the expression of numerous genes, and a higher rate of E{sub 2}-dependent tumor growth as xenografts. These studies indicate that LTEE causes adaptive responses in MCF-7 cells, which may reflect processes that contribute to the overall carcinogenic effect of E{sub 2}.

  3. Long-term estrogen exposure promotes carcinogen bioactivation, induces persistent changes in gene expression, and enhances the tumorigenicity of MCF-7 human breast cancer cells

    PubMed Central

    Spink, Barbara C.; Bennett, James A.; Pentecost, Brian T.; Lostritto, Nicole; Englert, Neal A.; Benn, Geoffrey K.; Goodenough, Angela K.; Turesky, Robert J.; Spink, David C.

    2009-01-01

    The cumulative exposure to estrogens is an important determinant in the risk of breast cancer, yet the full range of mechanisms involving estrogens in the genesis and progression of breast cancer remains a subject of debate. Interactions of estrogens and environmental toxicants have received attention as putative factors contributing to carcinogenesis. Mechanistic studies have demonstrated interactions between estrogen receptor α (ERα) and the aryl hydrocarbon receptor (AhR), with consequences on the genes that they regulate. Many studies of ERα and AhR-mediated effects and crosstalk between them have focused on the initial molecular events. In this study, we investigated ERα- and AhR-mediated effects in long-term estrogen exposed (LTEE) MCF-7 human breast cancer cells, which were obtained by continuous culturing for at least 12 weeks in medium supplemented with 1 nM of 17β-estradiol (E2). With these LTEE cells and with parallel control cells cultured without E2 supplementation, we performed an extensive study of cytochrome P450 (CYP) induction, carcinogen bioactivation, global gene expression, and tumorigenicity in immunocompromised mice. We found that LTEE cells, in comparison with control cells, had higher levels of AhR mRNA and protein, greater responsiveness for AhR-regulated CYP1A1 and CYP1B1 induction, a 6-fold higher initial level of benzo(a)pyrene-DNA adducts as determined by liquid chromatography tandem mass spectrometry, marked differences in the expression of numerous genes, and a higher rate of E2-dependent tumor growth as xenografts. These studies indicate that LTEE causes adaptive responses in MCF-7 cells, which may reflect processes that contribute to the overall carcinogenic effect of E2. PMID:19619570

  4. Regulation of ABO gene expression.

    PubMed

    Kominato, Yoshihiko; Hata, Yukiko; Matsui, Kazuhiro; Takizawa, Hisao

    2005-07-01

    The ABO blood group system is important in blood transfusions and in identifying individuals during criminal investigations. Two carbohydrate antigens, the A and B antigens, and their antibodies constitute this system. Although biochemical and molecular genetic studies have demonstrated the molecular basis of the histo-blood group ABO system, some aspects remain to be elucidated. To explain the molecular basis of how the ABO genes are controlled in cell type-specific expression, during normal cell differentiation, and in cancer cells with invasive and metastatic potential that lack A/B antigens, it is essential to understand the regulatory mechanism of ABO gene transcription. We review the transcriptional regulation of the ABO gene, including positive and negative elements in the upstream region of the gene, and draw some inferences that help to explain the phenomena described above.

  5. Gene expression profile of pulpitis

    PubMed Central

    Galicia, Johnah C.; Henson, Brett R.; Parker, Joel S.; Khan, Asma A.

    2016-01-01

    The cost, prevalence and pain associated with endodontic disease necessitate an understanding of the fundamental molecular aspects of its pathogenesis. This study was aimed to identify the genetic contributors to pulpal pain and inflammation. Inflamed pulps were collected from patients diagnosed with irreversible pulpitis (n=20). Normal pulps from teeth extracted for various reasons served as controls (n=20). Pain level was assessed using a visual analog scale (VAS). Genome-wide microarray analysis was performed using Affymetrix GeneTitan Multichannel Instrument. The difference in gene expression levels were determined by the Significance Analysis of Microarray program using a false discovery rate (q-value) of 5%. Genes involved in immune response, cytokine-cytokine receptor interaction and signaling, integrin cell surface interactions, and others were expressed at relatively higher levels in the in the pulpitis group. Moreover, several genes known to modulate pain and inflammation showed differential expression in asymptomatic and mild pain patients (≥30mm on VAS) compared to those with moderate to severe pain. This exploratory study provides a molecular basis for the clinical diagnosis of pulpitis. With an enhanced understanding of pulpal inflammation, future studies on treatment and management of pulpitis and on pain associated with it can have a biological reference to bridge treatment strategies with pulpal biology. PMID:27052691

  6. Gene expression profile of pulpitis.

    PubMed

    Galicia, J C; Henson, B R; Parker, J S; Khan, A A

    2016-06-01

    The cost, prevalence and pain associated with endodontic disease necessitate an understanding of the fundamental molecular aspects of its pathogenesis. This study was aimed to identify the genetic contributors to pulpal pain and inflammation. Inflamed pulps were collected from patients diagnosed with irreversible pulpitis (n=20). Normal pulps from teeth extracted for various reasons served as controls (n=20). Pain level was assessed using a visual analog scale (VAS). Genome-wide microarray analysis was performed using Affymetrix GeneTitan Multichannel Instrument. The difference in gene expression levels were determined by the significance analysis of microarray program using a false discovery rate (q-value) of 5%. Genes involved in immune response, cytokine-cytokine receptor interaction and signaling, integrin cell surface interactions, and others were expressed at relatively higher levels in the pulpitis group. Moreover, several genes known to modulate pain and inflammation showed differential expression in asymptomatic and mild pain patients (⩾30 mm on VAS) compared with those with moderate to severe pain. This exploratory study provides a molecular basis for the clinical diagnosis of pulpitis. With an enhanced understanding of pulpal inflammation, future studies on treatment and management of pulpitis and on pain associated with it can have a biological reference to bridge treatment strategies with pulpal biology.

  7. An in vivo and in vitro comparison of CYP gene induction in mice using liver slices and quantitative RT-PCR.

    PubMed

    Martignoni, Marcella; de Kanter, Ruben; Grossi, Pietro; Saturno, Grazia; Barbaria, Elena; Monshouwer, Mario

    2006-02-01

    The scope of this study was to compare in vitro and in vivo cytochrome P450 (CYP) gene induction in mice, using liver slices as an in vitro model. We have chosen to study mice to be able to better interpret CYP induction during long-term safety studies in this species. Mouse liver slices were incubated with beta-naphthoflavone (betaNF), phenobarbital (PB) or dexamethasone (DEX) for 24 h. In addition, in an in vivo study, mice were treated with the same compounds for three days. The mRNA expression of cyp1a1, cyp1a2, cyp2b10 and cyp3a11, which are important for drug metabolism and inducible by xenobiotics, were investigated in vivo and in vitro by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). Both in mouse liver slices and in vivo, betaNF was found to be a potent inducer of cyp1a1 and to a lesser extent of cyp1a2. All three compounds induced cyp2b10 mRNA levels, while the cyp3a11 mRNA level was induced only by DEX. Overall, these data demonstrated a good predictive in vitro-in vivo correlation of CYP induction.

  8. 17alpha-Ethinylestradiol decreases expression of multiple hepatic nucleotide excision repair genes in zebrafish (Danio rerio).

    PubMed

    Notch, Emily G; Miniutti, Danielle M; Mayer, Gregory D

    2007-10-15

    Waterborne 17alpha-ethinylestradiol (EE(2)) alters hormone-mediated biological indicators in fish. These alterations include increased plasma vitellogenin, increased intersex individuals, decreased egg and sperm production, reduced gamete quality, and complete feminization of male fish. Together, these observations implicate aquatic estrogens in a broad range of detrimental effects on fish reproduction and fitness. In addition to impairing reproductive processes, EE(2) is also a strong promoter of hepatic tumor formation. Since many ubiquitous, aquatic hepatocarcinogens form DNA adducts that are preferentially repaired by nucleotide excision repair (NER) processes, we hypothesized that EE(2) may exert co-carcinogenic effects by reducing an organisms ability to repair DNA adducts via this mechanism. The present study used fluorescence-based quantitative RT-PCR to examine effects of environmentally relevant concentrations of the semisynthetic estrogen, EE(2), on hepatic nucleotide excision repair (NER) gene expression. Adult male and female zebrafish (Danio rerio) were exposed to 1ng/L, 10ng/L or 100ng/L concentrations of EE(2), or to a solvent control (0.05%, v/v ethanol), for 7 days with static water renewal every 24h. Effectiveness of EE(2) exposure in the liver was confirmed by examining hepatic expression of two estrogen-responsive biomarkers, vitellogenin-1 and cytochrome P450-1A1 (CYP1A1). Quantitative analysis confirmed that exposure to 100ng/L EE(2) caused significant decreases in transcript abundance of several hepatic NER genes in male zebrafish, including XPC (>17-fold), XPA (>7-fold), XPD (>8-fold), and XPF (>8-fold). Adult female zebrafish exhibited a four-fold decreased in XPC mRNA abundance at all exposure concentrations. Decreased mRNA abundance of NER genes was also seen to a lesser degree at lower concentrations of EE(2). Adult male zebrafish showed greater reduction of hepatic NER transcript levels than their female counterparts, which is

  9. Gene expression throughout a vertebrate's embryogenesis

    PubMed Central

    2011-01-01

    Background Describing the patterns of gene expression during embryonic development has broadened our understanding of the processes and patterns that define morphogenesis. Yet gene expression patterns have not been described throughout vertebrate embryogenesis. This study presents statistical analyses of gene expression during all 40 developmental stages in the teleost Fundulus heteroclitus using four biological replicates per stage. Results Patterns of gene expression for 7,000 genes appear to be important as they recapitulate developmental timing. Among the 45% of genes with significant expression differences between pairs of temporally adjacent stages, significant differences in gene expression vary from as few as five to more than 660. Five adjacent stages have disproportionately more significant changes in gene expression (> 200 genes) relative to other stages: four to eight and eight to sixteen cell stages, onset of circulation, pre and post-hatch, and during complete yolk absorption. The fewest differences among adjacent stages occur during gastrulation. Yet, at stage 16, (pre-mid-gastrulation) the largest number of genes has peak expression. This stage has an over representation of genes in oxidative respiration and protein expression (ribosomes, translational genes and proteases). Unexpectedly, among all ribosomal genes, both strong positive and negative correlations occur. Similar correlated patterns of expression occur among all significant genes. Conclusions These data provide statistical support for the temporal dynamics of developmental gene expression during all stages of vertebrate development. PMID:21356103

  10. Does FACS perturb gene expression?

    PubMed

    Richardson, Graham M; Lannigan, Joanne; Macara, Ian G

    2015-02-01

    Fluorescence activated cell sorting is the technique most commonly used to separate primary mammary epithelial sub-populations. Many studies incorporate this technique before analyzing gene expression within specific cellular lineages. However, to our knowledge, no one has examined the effects of fluorescence activated cell sorting (FACS) separation on short-term transcriptional profiles. In this study, we isolated a heterogeneous mixture of cells from the mouse mammary gland. To determine the effects of the isolation and separation process on gene expression, we harvested RNA from the cells before enzymatic digestion, following enzymatic digestion, and following a mock FACS sort where the entire cohort of cells was retained. A strict protocol was followed to minimize disruption to the cells, and to ensure that no subpopulations were enriched or lost. Microarray analysis demonstrated that FACS causes minimal disruptions to gene expression patterns, but prior steps in the mammary cell isolation process are followed by upregulation of 18 miRNA's and rapid decreases in their predicted target transcripts. © 2015 International Society for Advancement of Cytometry.

  11. The Gene Expression Omnibus Database.

    PubMed

    Clough, Emily; Barrett, Tanya

    2016-01-01

    The Gene Expression Omnibus (GEO) database is an international public repository that archives and freely distributes high-throughput gene expression and other functional genomics data sets. Created in 2000 as a worldwide resource for gene expression studies, GEO has evolved with rapidly changing technologies and now accepts high-throughput data for many other data applications, including those that examine genome methylation, chromatin structure, and genome-protein interactions. GEO supports community-derived reporting standards that specify provision of several critical study elements including raw data, processed data, and descriptive metadata. The database not only provides access to data for tens of thousands of studies, but also offers various Web-based tools and strategies that enable users to locate data relevant to their specific interests, as well as to visualize and analyze the data. This chapter includes detailed descriptions of methods to query and download GEO data and use the analysis and visualization tools. The GEO homepage is at http://www.ncbi.nlm.nih.gov/geo/.

  12. Classification of genes based on gene expression analysis

    SciTech Connect

    Angelova, M. Myers, C. Faith, J.

    2008-05-15

    Systems biology and bioinformatics are now major fields for productive research. DNA microarrays and other array technologies and genome sequencing have advanced to the point that it is now possible to monitor gene expression on a genomic scale. Gene expression analysis is discussed and some important clustering techniques are considered. The patterns identified in the data suggest similarities in the gene behavior, which provides useful information for the gene functionalities. We discuss measures for investigating the homogeneity of gene expression data in order to optimize the clustering process. We contribute to the knowledge of functional roles and regulation of E. coli genes by proposing a classification of these genes based on consistently correlated genes in expression data and similarities of gene expression patterns. A new visualization tool for targeted projection pursuit and dimensionality reduction of gene expression data is demonstrated.

  13. Do single nucleotide polymorphisms in xenobiotic metabolizing genes determine breast cancer susceptibility and treatment outcomes?

    PubMed

    Singh, Virendra; Parmar, Devendra; Singh, Mahendra Pratap

    2008-10-01

    SNPs in CYP1A1, CYP2A1, CYP2B6, CYP2C, CYP2D6, CYP3A, GSTM1, GSTT1, GSTP1, SULT1A1, SULT1A2, UGT, and MTHFR are associated with breast cancer susceptibility; however, lack of such associations are also reported in some populations. The contradictory findings are explained on the basis of ethnic variation among populations and due to lack of proper sample size, detailed genotype-phenotype combinations and validation of gene expression studies at protein level. In this review, SNPs in these genes that have tremendous potential in identification of susceptible individuals, development of preventive strategies, treatment outcomes and their limitations are discussed.

  14. Harnessing gene expression networks to prioritize candidate epileptic encephalopathy genes.

    PubMed

    Oliver, Karen L; Lukic, Vesna; Thorne, Natalie P; Berkovic, Samuel F; Scheffer, Ingrid E; Bahlo, Melanie

    2014-01-01

    We apply a novel gene expression network analysis to a cohort of 182 recently reported candidate Epileptic Encephalopathy genes to identify those most likely to be true Epileptic Encephalopathy genes. These candidate genes were identified as having single variants of likely pathogenic significance discovered in a large-scale massively parallel sequencing study. Candidate Epileptic Encephalopathy genes were prioritized according to their co-expression with 29 known Epileptic Encephalopathy genes. We utilized developing brain and adult brain gene expression data from the Allen Human Brain Atlas (AHBA) and compared this to data from Celsius: a large, heterogeneous gene expression data warehouse. We show replicable prioritization results using these three independent gene expression resources, two of which are brain-specific, with small sample size, and the third derived from a heterogeneous collection of tissues with large sample size. Of the nineteen genes that we predicted with the highest likelihood to be true Epileptic Encephalopathy genes, two (GNAO1 and GRIN2B) have recently been independently reported and confirmed. We compare our results to those produced by an established in silico prioritization approach called Endeavour, and finally present gene expression networks for the known and candidate Epileptic Encephalopathy genes. This highlights sub-networks of gene expression, particularly in the network derived from the adult AHBA gene expression dataset. These networks give clues to the likely biological interactions between Epileptic Encephalopathy genes, potentially highlighting underlying mechanisms and avenues for therapeutic targets.

  15. Pulmonary Gene Expression Profiling of Inhaled Ricin

    DTIC Science & Technology

    2007-11-02

    in which 34 genes had statistically significant changes in gene expression. Transcripts identified by the assay included those that facilitate...gene expression. Transcripts identified by the assay included those that facilitate tissue healing (early growth response gene (egr)-1), regulate...impingement to determine aerosol concentration. Ricin concentrations from impinger samples were measured by protein assay (Pierce, MicroBCA, Rockford

  16. [Variability in the frequency of TCR-mutant lymphocytes associated with gene polymorphisms in women living in radiation-polluted areas].

    PubMed

    Sal'nikova, L E; Zamulaeva, I A; Saenko, A S; Abilev, S K; Rubanovich, A V

    2011-01-01

    The paper presents the results of an association study of a predisposition to increased somatic mutagenesis detected by the test for TCR-mutant lymphocytes (CD3-CD4+ phenotype). A study group consisted of 251 women who lived in the towns polluted by radionuclides after the Chernobyl accident and had estrogen-dependent reproductive system diseases (uterine myoma, fibrocystic mastopathy). The carriage of minor alleles in the genes (CYP1A1, GSTM1, and ABCB1) of all three stages of detoxification of xenobiotics was associated with the rise in the spontaneous frequency of TCR-mutant cells. Overweight modified the genotype (at CYP1A1 and GSTT1 loci) - environment interaction. When background radiation became higher, the contribution of minor alleles in the CYP1A1 genes to the instability recorded as the elevated frequency of TCR-mutant cells increased.

  17. Does inbreeding affect gene expression in birds?

    PubMed

    Hansson, Bengt; Naurin, Sara; Hasselquist, Dennis

    2014-09-01

    Inbreeding increases homozygosity, exposes genome-wide recessive deleterious alleles and often reduces fitness. The physiological and reproductive consequences of inbreeding may be manifested already during gene regulation, but the degree to which inbreeding influences gene expression is unknown in most organisms, including in birds. To evaluate the pattern of inbreeding-affected gene expression over the genome and in relation to sex, we performed a transcriptome-wide gene expression (10 695 genes) study of brain tissue of 10-day-old inbred and outbred, male and female zebra finches. We found significantly lower gene expression in females compared with males at Z-linked genes, confirming that dosage compensation is incomplete in female birds. However, inbreeding did not affect gene expression at autosomal or sex-linked genes, neither in males nor in females. Analyses of single genes again found a clear sex-biased expression at Z-linked genes, whereas only a single gene was significantly affected by inbreeding. The weak effect of inbreeding on gene expression in zebra finches contrasts to the situation, for example, in Drosophila where inbreeding has been found to influence gene expression more generally and at stress-related genes in particular.

  18. [Neuronal plasticity and gene expression].

    PubMed

    Sokolova, O O; Shtark, M B; Lisachev, P D

    2010-01-01

    Neuronal plasticity--a fundamental feature of brain--provides adequate interactions with dynamic environment. One of the most deeply investigated forms of the neuronal plasticity is a long-term potentiation (LTP)--a phenomenon underlying learning and memory. Signal paths activated during LTP converge into the nuclear of the neuron, giving rise to launch of the molecular-genetic programs, which mediate structural and functional remodeling of synapses. In the review data concerning involvement of multilevel gene expression into plastic change under neuronal activation are summarized.

  19. EGCG protects endothelial cells against PCB 126-induced inflammation through inhibition of AhR and induction of Nrf2-regulated genes

    SciTech Connect

    Han, Sung Gu; Han, Seong-Su; Toborek, Michal; Hennig, Bernhard

    2012-06-01

    Tea flavonoids such as epigallocatechin gallate (EGCG) protect against vascular diseases such as atherosclerosis via their antioxidant and anti-inflammatory functions. Persistent and widespread environmental pollutants, including polychlorinated biphenyls (PCB), can induce oxidative stress and inflammation in vascular endothelial cells. Even though PCBs are no longer produced, they are still detected in human blood and tissues and thus considered a risk for vascular dysfunction. We hypothesized that EGCG can protect endothelial cells against PCB-induced cell damage via its antioxidant and anti-inflammatory properties. To test this hypothesis, primary vascular endothelial cells were pretreated with EGCG, followed by exposure to the coplanar PCB 126. Exposure to PCB 126 significantly increased cytochrome P450 1A1 (Cyp1A1) mRNA and protein expression and superoxide production, events which were significantly attenuated following pretreatment with EGCG. Similarly, EGCG also reduced DNA binding of NF-κB and downstream expression of inflammatory markers such as monocyte chemotactic protein-1 (MCP-1) and vascular cell adhesion protein-1 (VCAM-1) after PCB exposure. Furthermore, EGCG decreased endogenous or base-line levels of Cyp1A1, MCP-1 and VCAM-1 in endothelial cells. Most of all, treatment of EGCG upregulated expression of NF-E2-related factor 2 (Nrf2)-controlled antioxidant genes, including glutathione S transferase (GST) and NAD(P)H:quinone oxidoreductase 1 (NQO1), in a dose-dependent manner. In contrast, silencing of Nrf2 increased Cyp1A1, MCP-1 and VCAM-1 and decreased GST and NQO1 expression, respectively. These data suggest that EGCG can inhibit AhR regulated genes and induce Nrf2-regulated antioxidant enzymes, thus providing protection against PCB-induced inflammatory responses in endothelial cells. -- Highlights: ► PCBs cause endothelial inflammation and subsequent atherosclerosis. ► Nutrition can modulate toxicity by environmental pollutants. ► We

  20. Thymoquinone regulates gene expression levels in the estrogen metabolic and interferon pathways in MCF7 breast cancer cells.

    PubMed

    Motaghed, Marjaneh; Al-Hassan, Faisal Muti; Hamid, Shahrul Sahul

    2014-01-01

    New drugs are continuously being developed for the treatment of patients with estrogen receptor-positive breast cancer. Thymoquinone is one of the drugs that exhibits anticancer characteristics based on in vivo and in vitro models. This study further investigates the effects of thymoquinone on human gene expression using cDNA microarray technology. The quantification of RNA samples was carried out using an Agilent 2100 Bioanalyser to determine the RNA integrity number (RIN). The Agilent Low Input Quick Amplification Labelling kit was used to generate cRNA in two-color microarray analysis. Samples with RIN >9.0 were used in this study. The universal human reference RNA was used as the common reference. The samples were labelled with cyanine-3 (cye-3) CTP dye and the universal human reference was labelled with cyanine-5 (cye-5) CTP dye. cRNA was purified with the RNeasy Plus Mini kit and quantified using a NanoDrop 2000c spectrophotometer. The arrays were scanned data analysed using Feature Extraction and GeneSpring software. Two-step qRT-PCR was selected to determine the relative gene expression using the High Capacity RNA-to-cDNA kit. The results from Gene Ontology (GO) analysis, indicated that 8 GO terms were related to biological processes (84%) and molecular functions (16%). A total of 577 entities showed >2-fold change in expression. Of these entities, 45.2% showed an upregulation and 54.7% showed a downregulation in expression. The interpretation of single experiment analysis (SEA) revealed that the cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) and UDP glucuronosyltransferase 1 family, polypeptide A8 (UGT1A8) genes in the estrogen metabolic pathway were downregulated significantly by 43- and 11‑fold, respectively. The solute carrier family 7 (anionic amino acid transporter light chain, xc-system), member 11 (SLC7A11) gene in the interferon pathway, reported to be involved in the development of chemoresistance, was downregulated by 15

  1. Resveratrol and its methoxy derivatives modulate the expression of estrogen metabolism enzymes in breast epithelial cells by AhR down-regulation.

    PubMed

    Licznerska, Barbara; Szaefer, Hanna; Wierzchowski, Marcin; Sobierajska, Hanna; Baer-Dubowska, Wanda

    2017-01-01

    Our earlier studies have shown that compared to resveratrol, its analogs with ortho-methoxy substituents exert stronger antiproliferative and proapoptotic activity. Since estrogens are considered the major risk factors of breast carcinogenesis, the aim of this study was to evaluate the effect of 3,4,2'-trimethoxy (3MS), 3,4,2',4'-tetramethoxy (4MS), and 3,4,2',4',6'-pentamethoxy (5MS) trans-stilbenes on the constitutive expression of the enzymes involved in estrogen metabolism, as well as receptors: AhR and HER2 in breast epithelial cell line MCF10A. The results showed different effect of resveratrol and its methoxy derivatives on the expression of genes encoding key enzymes of estrogen synthesis and catabolism. Resveratrol at the doses of 1 and 5 µmol/L increased the level of CYP19 transcript and protein level, while 5MS reduced mRNA transcript of both CYP19 and STS genes. Resveratrol and all its derivatives reduced also SULT1E1 mRNA transcript level. The reduced expression of AhR, CYP1A1, and 1B1 was also found as a result of treatment with these compounds. The most significant changes were found in the case of AhR. The most potent inhibitor of CYP1A1 and 1B1 genes expression was 5MS, which reduced the levels of mRNA transcript and protein of both CYPs from 31 to 89% of the initial levels. These results indicate that methoxy derivatives of resveratrol might be efficient modulators of estrogen metabolism. Moreover, the number of methoxy groups introduced to stilbene structure may play a certain role in this effect.

  2. Mechanoregulation of gene expression in fibroblasts

    PubMed Central

    Wang, James H.-C.; Thampatty, Bhavani P.; Lin, Jeen-Shang; Im, Hee-Jeong

    2010-01-01

    Mechanical loads placed on connective tissues alter gene expression in fibroblasts through mechanotransduction mechanisms by which cells convert mechanical signals into cellular biological events, such as gene expression of extracellular matrix components (e.g., collagen). This mechanical regulation of ECM gene expression affords maintenance of connective tissue homeostasis. However, mechanical loads can also interfere with homeostatic cellular gene expression and consequently cause the pathogenesis of connective tissue diseases such as tendinopathy and osteoarthritis. Therefore, the regulation of gene expression by mechanical loads is closely related to connective tissue physiology and pathology. This article reviews the effects of various mechanical loading conditions on gene regulation in fibroblasts and discusses several mechanotransduction mechanisms. Future research directions in mechanoregulation of gene expression are also suggested. PMID:17331678

  3. A Model for Aryl Hydrocarbon Receptor-Activated Gene Expression Shows Potency and Efficacy Changes and Predicts Squelching Due to Competition for Transcription Co-Activators

    PubMed Central

    Simon, Ted W.; Budinsky, Robert A.; Rowlands, J. Craig

    2015-01-01

    A stochastic model of nuclear receptor-mediated transcription was developed based on activation of the aryl hydrocarbon receptor (AHR) by 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and subsequent binding the activated AHR to xenobiotic response elements (XREs) on DNA. The model was based on effects observed in cells lines commonly used as in vitro experimental systems. Following ligand binding, the AHR moves into the cell nucleus and forms a heterodimer with the aryl hydrocarbon nuclear translocator (ARNT). In the model, a requirement for binding to DNA is that a generic coregulatory protein is subsequently bound to the AHR-ARNT dimer. Varying the amount of coregulator available within the nucleus altered both the potency and efficacy of TCDD for inducing for transcription of CYP1A1 mRNA, a commonly used marker for activation of the AHR. Lowering the amount of available cofactor slightly increased the EC50 for the transcriptional response without changing the efficacy or maximal response. Further reduction in the amount of cofactor reduced the efficacy and produced non-monotonic dose-response curves (NMDRCs) at higher ligand concentrations. The shapes of these NMDRCs were reminiscent of the phenomenon of squelching. Resource limitations for transcriptional machinery are becoming apparent in eukaryotic cells. Within single cells, nuclear receptor-mediated gene expression appears to be a stochastic process; however, intercellular communication and other aspects of tissue coordination may represent a compensatory process to maintain an organism’s ability to respond on a phenotypic level to various stimuli within an inconstant environment. PMID:26039703

  4. Differential Gene Expression in Human Cerebrovascular Malformations

    PubMed Central

    Shenkar, Robert; Elliott, J. Paul; Diener, Katrina; Gault, Judith; Hu, Ling-Jia; Cohrs, Randall J.; Phang, Tzulip; Hunter, Lawrence; Breeze, Robert E.; Awad, Issam A.

    2009-01-01

    OBJECTIVE We sought to identify genes with differential expression in cerebral cavernous malformations (CCMs), arteriovenous malformations (AVMs), and control superficial temporal arteries (STAs) and to confirm differential expression of genes previously implicated in the pathobiology of these lesions. METHODS Total ribonucleic acid was isolated from four CCM, four AVM, and three STA surgical specimens and used to quantify lesion-specific messenger ribonucleic acid expression levels on human gene arrays. Data were analyzed with the use of two separate methodologies: gene discovery and confirmation analysis. RESULTS The gene discovery method identified 42 genes that were significantly up-regulated and 36 genes that were significantly down-regulated in CCMs as compared with AVMs and STAs (P = 0.006). Similarly, 48 genes were significantly up-regulated and 59 genes were significantly down-regulated in AVMs as compared with CCMs and STAs (P = 0.006). The confirmation analysis showed significant differential expression (P < 0.05) in 11 of 15 genes (angiogenesis factors, receptors, and structural proteins) that previously had been reported to be expressed differentially in CCMs and AVMs in immunohistochemical analysis. CONCLUSION We identify numerous genes that are differentially expressed in CCMs and AVMs and correlate expression with the immunohistochemistry of genes implicated in cerebrovascular malformations. In future efforts, we will aim to confirm candidate genes specifically related to the pathobiology of cerebrovascular malformations and determine their biological systems and mechanistic relevance. PMID:12535382

  5. Norovirus gene expression and replication.

    PubMed

    Thorne, Lucy G; Goodfellow, Ian G

    2014-02-01

    Noroviruses are small, positive-sense RNA viruses within the family Caliciviridae, and are now accepted widely as a major cause of acute gastroenteritis in both developed and developing countries. Despite their impact, our understanding of the life cycle of noroviruses has lagged behind that of other RNA viruses due to the inability to culture human noroviruses (HuNVs). Our knowledge of norovirus biology has improved significantly over the past decade as a result of numerous technological advances. The use of a HuNV replicon, improved biochemical and cell-based assays, combined with the discovery of a murine norovirus capable of replication in cell culture, has improved greatly our understanding of the molecular mechanisms of norovirus genome translation and replication, as well as the interaction with host cell processes. In this review, the current state of knowledge of the intracellular life of noroviruses is discussed with particular emphasis on the mechanisms of viral gene expression and viral genome replication.

  6. Added value of stress related gene inductions in HepG2 cells as effect measurement in monitoring of air pollution

    NASA Astrophysics Data System (ADS)

    Nobels, Ingrid; Vanparys, Caroline; Van den Heuvel, Rosette; Vercauteren, Jordy; Blust, Ronny

    2012-08-01

    In this study we studied the effects of particulate matter samples (PM) through gene expression analysis in a routine air quality monitoring campaign by the Flemish Environment Agency (VMM, Belgium). We selected a human hepatoma (HepG2) multiple endpoint reporter assay for targeted stress related endpoint screening. Organic extracts of air samples (total suspended particles, TSP) were collected during one year in an industrial, urban and background location in Flanders, Belgium. Simultaneously, meteorological conditions (temperature, wind speed and precipitation) and particulate matter size ≤ 10 μM (PM10), organic (OC), elemental (EC) and total (TC) carbon were monitored and air samples were collected for chemical analysis (11 PAHs). Correlations between the induction of the different stress genes and the chemical pollutants were analysed. Exposure of HepG2 cells to daily air equivalents (20 m3) of organic TSP extracts revealed the dominant induction of the xenobiotic response element (Xre) and phase I (Cyp1A1) and phase II (GstYa) biotransformation enzymes. Additional effects were the induction of c-Fos, a proto-oncogen and Gadd45, a marker for cell cycle disturbance and responsive to genotoxic compounds. Inductions of other relevant pathways, such as sequestration of heavy metals, retinoids response, protein misfolding and increased cAMP levels were measured occasionally. A significant correlation was found between the genes Cyp1A1 (a typical marker for presence of PAHs and dioxin like compounds), c-Fos, Gadd45, (responsive to DNA damaging compounds) and the amount of PM10 and elemental carbon (EC) whereas no correlation was found between these genes and total PAHs content. This may suggest that the observed induction of Cyp1A1 and DNA damage related genes was provoked (partially) by other particle bound compounds (e.g. pesticides, PCBs, brominated flame retardants, dioxins, …), than PAHs. The contribution of particle bound compounds, other than PAHs might

  7. Familial aggregation analysis of gene expressions

    PubMed Central

    Rao, Shao-Qi; Xu, Liang-De; Zhang, Guang-Mei; Li, Xia; Li, Lin; Shen, Gong-Qing; Jiang, Yang; Yang, Yue-Ying; Gong, Bin-Sheng; Jiang, Wei; Zhang, Fan; Xiao, Yun; Wang, Qing K

    2007-01-01

    Traditional studies of familial aggregation are aimed at defining the genetic (and non-genetic) causes of a disease from physiological or clinical traits. However, there has been little attempt to use genome-wide gene expressions, the direct phenotypic measures of genes, as the traits to investigate several extended issues regarding the distributions of familially aggregated genes on chromosomes or in functions. In this study we conducted a genome-wide familial aggregation analysis by using the in vitro cell gene expressions of 3300 human autosome genes (Problem 1 data provided to Genetic Analysis Workshop 15) in order to answer three basic genetics questions. First, we investigated how gene expressions aggregate among different types (degrees) of relative pairs. Second, we conducted a bioinformatics analysis of highly familially aggregated genes to see how they are distributed on chromosomes. Third, we performed a gene ontology enrichment test of familially aggregated genes to find evidence to support their functional consensus. The results indicated that 1) gene expressions did aggregate in families, especially between sibs. Of 3300 human genes analyzed, there were a total of 1105 genes with one or more significant (empirical p < 0.05) familial correlation; 2) there were several genomic hot spots where highly familially aggregated genes (e.g., the chromosome 6 HLA genes cluster) were clustered; 3) as we expected, gene ontology enrichment tests revealed that the 1105 genes were aggregating not only in families but also in functional categories. PMID:18466548

  8. Methods for monitoring multiple gene expression

    SciTech Connect

    Berka, Randy; Bachkirova, Elena; Rey, Michael

    2012-05-01

    The present invention relates to methods for monitoring differential expression of a plurality of genes in a first filamentous fungal cell relative to expression of the same genes in one or more second filamentous fungal cells using microarrays containing Trichoderma reesei ESTs or SSH clones, or a combination thereof. The present invention also relates to computer readable media and substrates containing such array features for monitoring expression of a plurality of genes in filamentous fungal cells.

  9. Methods for monitoring multiple gene expression

    SciTech Connect

    Berka, Randy; Bachkirova, Elena; Rey, Michael

    2013-10-01

    The present invention relates to methods for monitoring differential expression of a plurality of genes in a first filamentous fungal cell relative to expression of the same genes in one or more second filamentous fungal cells using microarrays containing Trichoderma reesei ESTs or SSH clones, or a combination thereof. The present invention also relates to computer readable media and substrates containing such array features for monitoring expression of a plurality of genes in filamentous fungal cells.

  10. Methods for monitoring multiple gene expression

    DOEpatents

    Berka, Randy; Bachkirova, Elena; Rey, Michael

    2008-06-01

    The present invention relates to methods for monitoring differential expression of a plurality of genes in a first filamentous fungal cell relative to expression of the same genes in one or more second filamentous fungal cells using microarrays containing Trichoderma reesei ESTs or SSH clones, or a combination thereof. The present invention also relates to computer readable media and substrates containing such array features for monitoring expression of a plurality of genes in filamentous fungal cells.

  11. Estimation and Testing of Gene Expression Heterosis

    PubMed Central

    Liu, Peng; Nettleton, Dan

    2014-01-01

    Heterosis, also known as the hybrid vigor, occurs when the mean phenotype of hybrid off-spring is superior to that of its two inbred parents. The heterosis phenomenon is extensively utilized in agriculture though the molecular basis is still unknown. In an effort to understand phenotypic heterosis at the molecular level, researchers have begun to compare expression levels of thousands of genes between parental inbred lines and their hybrid offspring to search for evidence of gene expression heterosis. Standard statistical approaches for separately analyzing expression data for each gene can produce biased and highly variable estimates and unreliable tests of heterosis. To address these shortcomings, we develop a hierarchical model to borrow information across genes. Using our modeling framework, we derive empirical Bayes estimators and an inference strategy to identify gene expression heterosis. Simulation results show that our proposed method outperforms the more traditional strategy used to detect gene expression heterosis. This article has supplementary material online. PMID:25435758

  12. Estimation and Testing of Gene Expression Heterosis.

    PubMed

    Ji, Tieming; Liu, Peng; Nettleton, Dan

    2014-09-01

    Heterosis, also known as the hybrid vigor, occurs when the mean phenotype of hybrid off-spring is superior to that of its two inbred parents. The heterosis phenomenon is extensively utilized in agriculture though the molecular basis is still unknown. In an effort to understand phenotypic heterosis at the molecular level, researchers have begun to compare expression levels of thousands of genes between parental inbred lines and their hybrid offspring to search for evidence of gene expression heterosis. Standard statistical approaches for separately analyzing expression data for each gene can produce biased and highly variable estimates and unreliable tests of heterosis. To address these shortcomings, we develop a hierarchical model to borrow information across genes. Using our modeling framework, we derive empirical Bayes estimators and an inference strategy to identify gene expression heterosis. Simulation results show that our proposed method outperforms the more traditional strategy used to detect gene expression heterosis. This article has supplementary material online.

  13. Gene Expression Patterns in Ovarian Carcinomas

    PubMed Central

    Schaner, Marci E.; Ross, Douglas T.; Ciaravino, Giuseppe; Sørlie, Therese; Troyanskaya, Olga; Diehn, Maximilian; Wang, Yan C.; Duran, George E.; Sikic, Thomas L.; Caldeira, Sandra; Skomedal, Hanne; Tu, I-Ping; Hernandez-Boussard, Tina; Johnson, Steven W.; O'Dwyer, Peter J.; Fero, Michael J.; Kristensen, Gunnar B.; Børresen-Dale, Anne-Lise; Hastie, Trevor; Tibshirani, Robert; van de Rijn, Matt; Teng, Nelson N.; Longacre, Teri A.; Botstein, David; Brown, Patrick O.; Sikic, Branimir I.

    2003-01-01

    We used DNA microarrays to characterize the global gene expression patterns in surface epithelial cancers of the ovary. We identified groups of genes that distinguished the clear cell subtype from other ovarian carcinomas, grade I and II from grade III serous papillary carcinomas, and ovarian from breast carcinomas. Six clear cell carcinomas were distinguished from 36 other ovarian carcinomas (predominantly serous papillary) based on their gene expression patterns. The differences may yield insights into the worse prognosis and therapeutic resistance associated with clear cell carcinomas. A comparison of the gene expression patterns in the ovarian cancers to published data of gene expression in breast cancers revealed a large number of differentially expressed genes. We identified a group of 62 genes that correctly classified all 125 breast and ovarian cancer specimens. Among the best discriminators more highly expressed in the ovarian carcinomas were PAX8 (paired box gene 8), mesothelin, and ephrin-B1 (EFNB1). Although estrogen receptor was expressed in both the ovarian and breast cancers, genes that are coregulated with the estrogen receptor in breast cancers, including GATA-3, LIV-1, and X-box binding protein 1, did not show a similar pattern of coexpression in the ovarian cancers. PMID:12960427

  14. Arabidopsis gene expression patterns during spaceflight

    NASA Astrophysics Data System (ADS)

    Paul, A.-L.; Ferl, R. J.

    The exposure of Arabidopsis thaliana (Arabidopsis) plants to spaceflight environments resulted in the differential expression of hundreds of genes. A 5 day mission on orbiter Columbia in 1999 (STS-93) carried transgenic Arabidopsis plants engineered with a transgene composed of the alcohol dehydrogenase (Adh) gene promoter linked to the β -Glucuronidase (GUS) reporter gene. The plants were used to evaluate the effects of spaceflight on two fronts. First, expression patterns visualized with the Adh/GUS transgene were used to address specifically the possibility that spaceflight induces a hypoxic stress response, and to assess whether any spaceflight response was similar to control terrestrial hypoxia-induced gene expression patterns. (Paul et al., Plant Physiol. 2001, 126:613). Second, genome-wide patterns of native gene expression were evaluated utilizing the Affymetrix ATH1 GeneChip? array of 8,000 Arabidopsis genes. As a control for the veracity of the array analyses, a selection of genes identified with the arrays was further characterized with quantitative Real-Time RT PCR (ABI - TaqmanTM). Comparison of the patterns of expression for arrays of hybridized with RNA isolated from plants exposed to spaceflight compared to the control arrays revealed hundreds of genes that were differentially expressed in response to spaceflight, yet most genes that are hallmarks of hypoxic stress were unaffected. These results will be discussed in light of current models for plant responses to the spaceflight environment, and with regard to potential future flight opportunities.

  15. Combination effect of cytochrome P450 1A1 gene polymorphisms on uterine leiomyoma: A case-control study

    PubMed Central

    Salimi, Saeedeh; Sajadian, Mojtaba; Khodamian, Maryam; Yazdi, Atefeh; Rezaee, Soodabeh; Mohammadpour-Gharehbagh, Abbas; Mokhtari, Mojgan; Yaghmaie, Minoo

    2016-01-01

    Uterine leiomyoma (UL) is an estrogen-dependent neoplasm of the uterus, and estrogen metabolizing enzymes affect its progression. This study aimed to evaluate the association between two single-nucleotide polymorphisms of cytochrome P450 1A1 (CYP1A1) gene and UL risk. The study consisted of 105 patients with UL and 112 healthy women as controls. Ile462Val (A/G) and Asp449Asp (T/C) polymorphisms of CYP1A1 gene were analyzed by DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism methods, respectively. The findings indicated no association between Ile462Val (A/G) and Asp449Asp (T/C) polymorphisms of CYP1A1 gene and UL (p < 0.05). However, the combination effect of TT/AG genotypes of the Asp449Asp (T/C) and Ile462Val (A/G) polymorphisms was associated with 4.3-fold higher risk of UL. In addition, haplotype analysis revealed that TG haplotype of the Asp449Asp (T/C) and Ile462Val (A/G) polymorphisms could increase the UL risk nearly 4.9-fold. Asp449Asp (T/C) and Ile462Val (A/G) polymorphisms of CYP1A1 gene were not associated with UL susceptibility; however, the combination of the TT/AG genotypes and TG haplotype could increase the UL risk. PMID:27333216

  16. Stratified gene expression analysis identifies major amyotrophic lateral sclerosis genes.

    PubMed

    Jones, Ashley R; Troakes, Claire; King, Andrew; Sahni, Vibhu; De Jong, Simone; Bossers, Koen; Papouli, Efterpi; Mirza, Muddassar; Al-Sarraj, Safa; Shaw, Christopher E; Shaw, Pamela J; Kirby, Janine; Veldink, Jan H; Macklis, Jeffrey D; Powell, John F; Al-Chalabi, Ammar

    2015-05-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of motor neurons resulting in progressive paralysis. Gene expression studies of ALS only rarely identify the same gene pathways as gene association studies. We hypothesized that analyzing tissues by matching on degree of disease severity would identify different patterns of gene expression from a traditional case-control comparison. We analyzed gene expression changes in 4 postmortem central nervous system regions, stratified by severity of motor neuron loss. An overall comparison of cases (n = 6) and controls (n = 3) identified known ALS gene, SOX5, as showing differential expression (log2 fold change = 0.09, p = 5.5 × 10(-5)). Analyses stratified by disease severity identified expression changes in C9orf72 (p = 2.77 × 10(-3)), MATR3 (p = 3.46 × 10(-3)), and VEGFA (p = 8.21 × 10(-4)), all implicated in ALS through genetic studies, and changes in other genes in pathways involving RNA processing and immune response. These findings suggest that analysis of gene expression stratified by disease severity can identify major ALS genes and may be more efficient than traditional case-control comparison.

  17. Suppression of cytokine-mediated complement factor gene expression through selective activation of the Ah receptor with 3',4'-dimethoxy-α-naphthoflavone.

    PubMed

    Murray, Iain A; Flaveny, Colin A; Chiaro, Christopher R; Sharma, Arun K; Tanos, Rachel S; Schroeder, Jennifer C; Amin, Shantu G; Bisson, William H; Kolluri, Siva K; Perdew, Gary H

    2011-03-01

    We have characterized previously a class of aryl hydrocarbon receptor (AHR) ligand termed selective AHR modulators (SAhRMs). SAhRMs exhibit anti-inflammatory properties, including suppression of cytokine-mediated acute phase genes (e.g., Saa1), through dissociation of non-dioxin-response element (DRE) AHR activity from DRE-dependent xenobiotic gene expression. The partial AHR agonist α-naphthoflavone (αNF) mediates the suppressive, non-DRE dependent effects on SAA1 expression and partial DRE-mediated CYP1A1 induction. These observations suggest that αNF may be structurally modified to a derivative exhibiting only SAhRM activity. A screen of αNF derivatives identifies 3',4'-dimethoxy-αNF (DiMNF) as a candidate SAhRM. Competitive ligand binding validates DiMNF as an AHR ligand, and DRE-dependent reporter assays with quantitative mRNA analysis of AHR target genes reveal minimal agonist activity associated with AHR binding. Consistent with loss of agonist activity, DiMNF fails to promote AHR binding to DRE probes as determined through electromobility shift assay. Importantly, mRNA analysis indicates that DiMNF retains the suppressive capacity of αNF regarding cytokine-mediated SAA1 expression in Huh7 cells. Interestingly, predictive docking modeling suggests that DiMNF adopts a unique orientation within the AHR ligand binding pocket relative to αNF and may facilitate the rational design of additional SAhRMs. Microarray studies with a non-DRE binding but otherwise functional AHR mutant identified complement factor C3 as a potential SAhRM target. We confirmed this observation in Huh7 cells using 10 μM DiMNF, which significantly repressed C3 mRNA and protein. These data expand the classes of AHR ligands exerting DRE-independent anti-inflammatory SAhRM activity, suggesting SAhRMs may have application in the amelioration of inflammatory disorders.

  18. Gene Expression Noise, Fitness Landscapes, and Evolution

    NASA Astrophysics Data System (ADS)

    Charlebois, Daniel

    The stochastic (or noisy) process of gene expression can have fitness consequences for living organisms. For example, gene expression noise facilitates the development of drug resistance by increasing the time scale at which beneficial phenotypic states can be maintained. The present work investigates the relationship between gene expression noise and the fitness landscape. By incorporating the costs and benefits of gene expression, we track how the fluctuation magnitude and timescale of expression noise evolve in simulations of cell populations under stress. We find that properties of expression noise evolve to maximize fitness on the fitness landscape, and that low levels of expression noise emerge when the fitness benefits of gene expression exceed the fitness costs (and that high levels of noise emerge when the costs of expression exceed the benefits). The findings from our theoretical/computational work offer new hypotheses on the development of drug resistance, some of which are now being investigated in evolution experiments in our laboratory using well-characterized synthetic gene regulatory networks in budding yeast. Nserc Postdoctoral Fellowship (Grant No. PDF-453977-2014).

  19. Gene expression in the etiology of schizophrenia.

    PubMed

    Bray, Nicholas J

    2008-05-01

    Gene expression represents a fundamental interface between genes and environment in the development and ongoing plasticity of the human brain. Individual differences in gene expression are likely to underpin much of human diversity, including psychiatric illness. In the past decade, the development of microarray and proteomic technology has enabled global description of gene expression in schizophrenia. However, it is difficult on the basis of gene expression assays alone to distinguish between those changes that constitute primary etiology and those that reflect secondary pathology, compensatory mechanisms, or confounding influences. In this respect, tests of genetic association with schizophrenia will be instructive because changes in gene expression that result from gene variants that are associated with the disorder are likely to be of primary etiological significance. However, regulatory polymorphism is extremely difficult to recognize on the basis of sequence interrogation alone. Functional assays at the messenger RNA and/or protein level will be essential in elucidating the molecular mechanisms underlying genetic association with schizophrenia and are likely to become increasingly important in the identification of regulatory variants with which to test for association with the disorder and related traits. Once established, etiologically relevant changes in gene expression can be recapitulated in model systems in order to elucidate the molecular and physiological pathways that may ultimately give rise to the condition.

  20. Hexachlorobenzene and pentachlorobenzene accumulation, metabolism and effect on steroid secretion and on CYP11A1 and CYP19 expression in cultured human placental tissue.

    PubMed

    Gregoraszczuk, E L; Ptak, A; Karpeta, A; Fiedor, E; Wróbel, A; Milewicz, T; Falandysz, J

    2014-01-01

    Hexachlorobenzene and pentachlorobenzene accumulation and the effect on CYP1A1, SULT1A, COMT and steroid secretion in term placental tissue were determined. Explants of placental tissue were exposed to between 0.02 and 2 ng/ml HCBz or PeCBz for 6-72 h. Accumulation was measured by capillary gas chromatography and quadrupole mass spectrometry. CYP1A1, SULT1A, COMT activity and progesterone secretion were analysed by EIA. Protein expression was quantified by Western blot; 6% HCBz and 7% PeCBz were detected in the tissue. Fast induction of CYP1A1 activity and protein expression in the presence of HCBz were observed. HCBz increased, while PeCBz decreased COMT protein expression. The stimulatory effect of HCBz, and the inhibitory of PeCBz on progesterone secretion and CYP11A1 protein expression were noted. Later activation of CYP1A1, inhibition of COMT protein expression and progesterone secretion by PeCBz suggest greater exposure to PeCBz and pointing at PeCBz as the main factor responsible for the disruption of placental function.

  1. Noise minimisation in gene expression switches.

    PubMed

    Monteoliva, Diana; McCarthy, Christina B; Diambra, Luis

    2013-01-01

    Gene expression is subject to stochastic variation which leads to fluctuations in the rate of protein production. Recently, a study in yeast at a genomic scale showed that, in some cases, gene expression variability alters phenotypes while, in other cases, these remain unchanged despite fluctuations in the expression of other genes. These studies suggested that noise in gene expression is a physiologically relevant trait and, to prevent harmful stochastic variation in the expression levels of some genes, it can be subject to minimisation. However, the mechanisms for noise minimisation are still unclear. In the present work, we analysed how noise expression depends on the architecture of the cis-regulatory system, in particular on the number of regulatory binding sites. Using analytical calculations and stochastic simulations, we found that the fluctuation level in noise expression decreased with the number of regulatory sites when regulatory transcription factors interacted with only one other bound transcription factor. In contrast, we observed that there was an optimal number of binding sites when transcription factors interacted with many bound transcription factors. This finding suggested a new mechanism for preventing large fluctuations in the expression of genes which are sensitive to the concentration of regulators.

  2. Noise Minimisation in Gene Expression Switches

    PubMed Central

    Monteoliva, Diana; McCarthy, Christina B.; Diambra, Luis

    2013-01-01

    Gene expression is subject to stochastic variation which leads to fluctuations in the rate of protein production. Recently, a study in yeast at a genomic scale showed that, in some cases, gene expression variability alters phenotypes while, in other cases, these remain unchanged despite fluctuations in the expression of other genes. These studies suggested that noise in gene expression is a physiologically relevant trait and, to prevent harmful stochastic variation in the expression levels of some genes, it can be subject to minimisation. However, the mechanisms for noise minimisation are still unclear. In the present work, we analysed how noise expression depends on the architecture of the cis-regulatory system, in particular on the number of regulatory binding sites. Using analytical calculations and stochastic simulations, we found that the fluctuation level in noise expression decreased with the number of regulatory sites when regulatory transcription factors interacted with only one other bound transcription factor. In contrast, we observed that there was an optimal number of binding sites when transcription factors interacted with many bound transcription factors. This finding suggested a new mechanism for preventing large fluctuations in the expression of genes which are sensitive to the concentration of regulators. PMID:24376783

  3. Nucleosome repositioning underlies dynamic gene expression.

    PubMed

    Nocetti, Nicolas; Whitehouse, Iestyn

    2016-03-15

    Nucleosome repositioning at gene promoters is a fundamental aspect of the regulation of gene expression. However, the extent to which nucleosome repositioning is used within eukaryotic genomes is poorly understood. Here we report a comprehensive analysis of nucleosome positions as budding yeast transit through an ultradian cycle in which expression of >50% of all genes is highly synchronized. We present evidence of extensive nucleosome repositioning at thousands of gene promoters as genes are activated and repressed. During activation, nucleosomes are relocated to allow sites of general transcription factor binding and transcription initiation to become accessible. The extent of nucleosome shifting is closely related to the dynamic range of gene transcription and generally related to DNA sequence properties and use of the coactivators TFIID or SAGA. However, dynamic gene expression is not limited to SAGA-regulated promoters and is an inherent feature of most genes. While nucleosome repositioning occurs pervasively, we found that a class of genes required for growth experience acute nucleosome shifting as cells enter the cell cycle. Significantly, our data identify that the ATP-dependent chromatin-remodeling enzyme Snf2 plays a fundamental role in nucleosome repositioning and the expression of growth genes. We also reveal that nucleosome organization changes extensively in concert with phases of the cell cycle, with large, regularly spaced nucleosome arrays being established in mitosis. Collectively, our data and analysis provide a framework for understanding nucleosome dynamics in relation to fundamental DNA-dependent transactions.

  4. Gene Expression Patterns in Human Liver Cancers

    PubMed Central

    Chen, Xin; Cheung, Siu Tim; So, Samuel; Fan, Sheung Tat; Barry, Christopher; Higgins, John; Lai, Kin-Man; Ji, Jiafu; Dudoit, Sandrine; Ng, Irene O.L.; van de Rijn, Matt; Botstein, David; Brown, Patrick O.

    2002-01-01

    Hepatocellular carcinoma (HCC) is a leading cause of death worldwide. Using cDNA microarrays to characterize patterns of gene expression in HCC, we found consistent differences between the expression patterns in HCC compared with those seen in nontumor liver tissues. The expression patterns in HCC were also readily distinguished from those associated with tumors metastatic to liver. The global gene expression patterns intrinsic to each tumor were sufficiently distinctive that multiple tumor nodules from the same patient could usually be recognized and distinguished from all the others in the large sample set on the basis of their gene expression patterns alone. The distinctive gene expression patterns are characteristic of the tumors and not the patient; the expression programs seen in clonally independent tumor nodules in the same patient were no more similar than those in tumors from different patients. Moreover, clonally related tumor masses that showed distinct expression profiles were also distinguished by genotypic differences. Some features of the gene expression patterns were associated with specific phenotypic and genotypic characteristics of the tumors, including growth rate, vascular invasion, and p53 overexpression. PMID:12058060

  5. Digital gene expression signatures for maize development.

    PubMed

    Eveland, Andrea L; Satoh-Nagasawa, Namiko; Goldshmidt, Alexander; Meyer, Sandra; Beatty, Mary; Sakai, Hajime; Ware, Doreen; Jackson, David

    2010-11-01

    Genome-wide expression signatures detect specific perturbations in developmental programs and contribute to functional resolution of key regulatory networks. In maize (Zea mays) inflorescences, mutations in the RAMOSA (RA) genes affect the determinacy of axillary meristems and thus alter branching patterns, an important agronomic trait. In this work, we developed and tested a framework for analysis of tag-based, digital gene expression profiles using Illumina's high-throughput sequencing technology and the newly assembled B73 maize reference genome. We also used a mutation in the RA3 gene to identify putative expression signatures specific to stem cell fate in axillary meristem determinacy. The RA3 gene encodes a trehalose-6-phosphate phosphatase and may act at the interface between developmental and metabolic processes. Deep sequencing of digital gene expression libraries, representing three biological replicate ear samples from wild-type and ra3 plants, generated 27 million 20- to 21-nucleotide reads with frequencies spanning 4 orders of magnitude. Unique sequence tags were anchored to 3'-ends of individual transcripts by DpnII and NlaIII digests, which were multiplexed during sequencing. We mapped 86% of nonredundant signature tags to the maize genome, which associated with 37,117 gene models and unannotated regions of expression. In total, 66% of genes were detected by at least nine reads in immature maize ears. We used comparative genomics to leverage existing information from Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) in functional analyses of differentially expressed maize genes. Results from this study provide a basis for the analysis of short-read expression data in maize and resolved specific expression signatures that will help define mechanisms of action for the RA3 gene.

  6. Gene expression homeostasis and chromosome architecture

    PubMed Central

    Seshasayee, Aswin Sai Narain

    2014-01-01

    In rapidly growing populations of bacterial cells, including those of the model organism Escherichia coli, genes essential for growth - such as those involved in protein synthesis - are expressed at high levels; this is in contrast to many horizontally-acquired genes, which are maintained at low transcriptional levels.1 This balance in gene expression states between 2 distinct classes of genes is established by a galaxy of transcriptional regulators, including the so-called nucleoid associated proteins (NAP) that contribute to shaping the chromosome.2 Besides these active players in gene regulation, it is not too far-fetched to anticipate that genome organization in terms of how genes are arranged on the chromosome,3 which is the result of long-drawn transactions among genome rearrangement processes and selection, and the manner in which it is structured inside the cell, plays a role in establishing this balance. A recent study from our group has contributed to the literature investigating the interplay between global transcriptional regulators and genome organization in establishing gene expression homeostasis.4 In particular, we address a triangle of functional interactions among genome organization, gene expression homeostasis and horizontal gene transfer. PMID:25997086

  7. Unmasking ultradian rhythms in gene expression

    PubMed Central

    van der Veen, Daan R.; Gerkema, Menno P.

    2017-01-01

    Biological oscillations with an ultradian time scale of 1 to several hours include cycles in behavioral arousal, episodic glucocorticoid release, and gene expression. Ultradian rhythms are thought to have an extrinsic origin because of a perceived absence of ultradian rhythmicity in vitro and a lack of known molecular ultradian oscillators. We designed a novel, non–spectral-analysis method of separating ultradian from circadian components and applied it to a published gene expression dataset with an ultradian sampling resolution. Ultradian rhythms in mouse hepatocytes in vivo have been published, and we validated our approach using this control by confirming 175 of 323 ultradian genes identified in a prior study and found 862 additional ultradian genes. For the first time, we now report ultradian expression of >900 genes in vitro. Sixty genes exhibited ultradian transcriptional rhythmicity, both in vivo and in vitro, including 5 genes involved in the cell cycle. Within these 60 genes, we identified significant enrichment of specific DNA motifs in the 1000 bp proximal promotor, some of which associate with known transcriptional factors. These findings are in strong support of instrinsically driven ultradian rhythms and expose potential molecular mechanisms and functions underlying ultradian rhythms that remain unknown.—Van der Veen, D. R., Gerkema, M. P. Unmasking ultradian rhythms in gene expression. PMID:27871062

  8. Expression of polarity genes in human cancer.

    PubMed

    Lin, Wan-Hsin; Asmann, Yan W; Anastasiadis, Panos Z

    2015-01-01

    Polarity protein complexes are crucial for epithelial apical-basal polarity and directed cell migration. Since alterations of these processes are common in cancer, polarity proteins have been proposed to function as tumor suppressors or oncogenic promoters. Here, we review the current understanding of polarity protein functions in epithelial homeostasis, as well as tumor formation and progression. As most previous studies focused on the function of single polarity proteins in simplified model systems, we used a genomics approach to systematically examine and identify the expression profiles of polarity genes in human cancer. The expression profiles of polarity genes were distinct in different human tissues and classified cancer types. Additionally, polarity expression profiles correlated with disease progression and aggressiveness, as well as with identified cancer types, where specific polarity genes were commonly altered. In the case of Scribble, gene expression analysis indicated its common amplification and upregulation in human cancer, suggesting a tumor promoting function.

  9. Regulation of Gene Expression in Protozoa Parasites

    PubMed Central

    Gomez, Consuelo; Esther Ramirez, M.; Calixto-Galvez, Mercedes; Medel, Olivia; Rodríguez, Mario A.

    2010-01-01

    Infections with protozoa parasites are associated with high burdens of morbidity and mortality across the developing world. Despite extensive efforts to control the transmission of these parasites, the spread of populations resistant to drugs and the lack of effective vaccines against them contribute to their persistence as major public health problems. Parasites should perform a strict control on the expression of genes involved in their pathogenicity, differentiation, immune evasion, or drug resistance, and the comprehension of the mechanisms implicated in that control could help to develop novel therapeutic strategies. However, until now these mechanisms are poorly understood in protozoa. Recent investigations into gene expression in protozoa parasites suggest that they possess many of the canonical machineries employed by higher eukaryotes for the control of gene expression at transcriptional, posttranscriptional, and epigenetic levels, but they also contain exclusive mechanisms. Here, we review the current understanding about the regulation of gene expression in Plasmodium sp., Trypanosomatids, Entamoeba histolytica and Trichomonas vaginalis. PMID:20204171

  10. Dynamic modeling of gene expression data

    NASA Technical Reports Server (NTRS)

    Holter, N. S.; Maritan, A.; Cieplak, M.; Fedoroff, N. V.; Banavar, J. R.

    2001-01-01

    We describe the time evolution of gene expression levels by using a time translational matrix to predict future expression levels of genes based on their expression levels at some initial time. We deduce the time translational matrix for previously published DNA microarray gene expression data sets by modeling them within a linear framework by using the characteristic modes obtained by singular value decomposition. The resulting time translation matrix provides a measure of the relationships among the modes and governs their time evolution. We show that a truncated matrix linking just a few modes is a good approximation of the full time translation matrix. This finding suggests that the number of essential connections among the genes is small.

  11. Mining Gene Expression Data of Multiple Sclerosis

    PubMed Central

    Zhu, Zhenli; Huang, Zhengliang; Li, Ke

    2014-01-01

    Objectives Microarray produces a large amount of gene expression data, containing various biological implications. The challenge is to detect a panel of discriminative genes associated with disease. This study proposed a robust classification model for gene selection using gene expression data, and performed an analysis to identify disease-related genes using multiple sclerosis as an example. Materials and methods Gene expression profiles based on the transcriptome of peripheral blood mononuclear cells from a total of 44 samples from 26 multiple sclerosis patients and 18 individuals with other neurological diseases (control) were analyzed. Feature selection algorithms including Support Vector Machine based on Recursive Feature Elimination, Receiver Operating Characteristic Curve, and Boruta algorithms were jointly performed to select candidate genes associating with multiple sclerosis. Multiple classification models categorized samples into two different groups based on the identified genes. Models’ performance was evaluated using cross-validation methods, and an optimal classifier for gene selection was determined. Results An overlapping feature set was identified consisting of 8 genes that were differentially expressed between the two phenotype groups. The genes were significantly associated with the pathways of apoptosis and cytokine-cytokine receptor interaction. TNFSF10 was significantly associated with multiple sclerosis. A Support Vector Machine model was established based on the featured genes and gave a practical accuracy of ∼86%. This binary classification model also outperformed the other models in terms of Sensitivity, Specificity and F1 score. Conclusions The combined analytical framework integrating feature ranking algorithms and Support Vector Machine model could be used for selecting genes for other diseases. PMID:24932510

  12. Amino acid regulation of gene expression.

    PubMed Central

    Fafournoux, P; Bruhat, A; Jousse, C

    2000-01-01

    The impact of nutrients on gene expression in mammals has become an important area of research. Nevertheless, the current understanding of the amino acid-dependent control of gene expression is limited. Because amino acids have multiple and important functions, their homoeostasis has to be finely maintained. However, amino-acidaemia can be affected by certain nutritional conditions or various forms of stress. It follows that mammals have to adjust several of their physiological functions involved in the adaptation to amino acid availability by regulating the expression of numerous genes. The aim of the present review is to examine the role of amino acids in regulating mammalian gene expression and protein turnover. It has been reported that some genes involved in the control of growth or amino acid metabolism are regulated by amino acid availability. For instance, limitation of several amino acids greatly increases the expression of the genes encoding insulin-like growth factor binding protein-1, CHOP (C/EBP homologous protein, where C/EBP is CCAAT/enhancer binding protein) and asparagine synthetase. Elevated mRNA levels result from both an increase in the rate of transcription and an increase in mRNA stability. Several observations suggest that the amino acid regulation of gene expression observed in mammalian cells and the general control process described in yeast share common features. Moreover, amino acid response elements have been characterized in the promoters of the CHOP and asparagine synthetase genes. Taken together, the results discussed in the present review demonstrate that amino acids, by themselves, can, in concert with hormones, play an important role in the control of gene expression. PMID:10998343

  13. Imputing gene expression to maximize platform compatibility.

    PubMed

    Zhou, Weizhuang; Han, Lichy; Altman, Russ B

    2017-02-15

    Microarray measurements of gene expression constitute a large fraction of publicly shared biological data, and are available in the Gene Expression Omnibus (GEO). Many studies use GEO data to shape hypotheses and improve statistical power. Within GEO, the Affymetrix HG-U133A and HG-U133 Plus 2.0 are the two most commonly used microarray platforms for human samples; the HG-U133 Plus 2.0 platform contains 54 220 probes and the HG-U133A array contains a proper subset (21 722 probes). When different platforms are involved, the subset of common genes is most easily compared. This approach results in the exclusion of substantial measured data and can limit downstream analysis. To predict the expression values for the genes unique to the HG-U133 Plus 2.0 platform, we constructed a series of gene expression inference models based on genes common to both platforms. Our model predicts gene expression values that are within the variability observed in controlled replicate studies and are highly correlated with measured data. Using six previously published studies, we also demonstrate the improved performance of the enlarged feature space generated by our model in downstream analysis.

  14. Optimal Reference Genes for Gene Expression Normalization in Trichomonas vaginalis.

    PubMed

    dos Santos, Odelta; de Vargas Rigo, Graziela; Frasson, Amanda Piccoli; Macedo, Alexandre José; Tasca, Tiana

    2015-01-01

    Trichomonas vaginalis is the etiologic agent of trichomonosis, the most common non-viral sexually transmitted disease worldwide. This infection is associated with several health consequences, including cervical and prostate cancers and HIV acquisition. Gene expression analysis has been facilitated because of available genome sequences and large-scale transcriptomes in T. vaginalis, particularly using quantitative real-time polymerase chain reaction (qRT-PCR), one of the most used methods for molecular studies. Reference genes for normalization are crucial to ensure the accuracy of this method. However, to the best of our knowledge, a systematic validation of reference genes has not been performed for T. vaginalis. In this study, the transcripts of nine candidate reference genes were quantified using qRT-PCR under different cultivation conditions, and the stability of these genes was compared using the geNorm and NormFinder algorithms. The most stable reference genes were α-tubulin, actin and DNATopII, and, conversely, the widely used T. vaginalis reference genes GAPDH and β-tubulin were less stable. The PFOR gene was used to validate the reliability of the use of these candidate reference genes. As expected, the PFOR gene was upregulated when the trophozoites were cultivated with ferrous ammonium sulfate when the DNATopII, α-tubulin and actin genes were used as normalizing gene. By contrast, the PFOR gene was downregulated when the GAPDH gene was used as an internal control, leading to misinterpretation of the data. These results provide an important starting point for reference gene selection and gene expression analysis with qRT-PCR studies of T. vaginalis.

  15. Perspectives: Gene Expression in Fisheries Management

    USGS Publications Warehouse

    Nielsen, Jennifer L.; Pavey, Scott A.

    2010-01-01

    Functional genes and gene expression have been connected to physiological traits linked to effective production and broodstock selection in aquaculture, selective implications of commercial fish harvest, and adaptive changes reflected in non-commercial fish populations subject to human disturbance and climate change. Gene mapping using single nucleotide polymorphisms (SNPs) to identify functional genes, gene expression (analogue microarrays and real-time PCR), and digital sequencing technologies looking at RNA transcripts present new concepts and opportunities in support of effective and sustainable fisheries. Genomic tools have been rapidly growing in aquaculture research addressing aspects of fish health, toxicology, and early development. Genomic technologies linking effects in functional genes involved in growth, maturation and life history development have been tied to selection resulting from harvest practices. Incorporating new and ever-increasing knowledge of fish genomes is opening a different perspective on local adaptation that will prove invaluable in wild fish conservation and management. Conservation of fish stocks is rapidly incorporating research on critical adaptive responses directed at the effects of human disturbance and climate change through gene expression studies. Genomic studies of fish populations can be generally grouped into three broad categories: 1) evolutionary genomics and biodiversity; 2) adaptive physiological responses to a changing environment; and 3) adaptive behavioral genomics and life history diversity. We review current genomic research in fisheries focusing on those that use microarrays to explore differences in gene expression among phenotypes and within or across populations, information that is critically important to the conservation of fish and their relationship to humans.

  16. Control of gene expression in trypanosomes.

    PubMed Central

    Vanhamme, L; Pays, E

    1995-01-01

    Trypanosomes are protozoan agents of major parasitic diseases such as Chagas' disease in South America and sleeping sickness of humans and nagana disease of cattle in Africa. They are transmitted to mammalian hosts by specific insect vectors. Their life cycle consists of a succession of differentiation and growth phases requiring regulated gene expression to adapt to the changing extracellular environment. Typical of such stage-specific expression is that of the major surface antigens of Trypanosoma brucei, procyclin in the procyclic (insect) form and the variant surface glycoprotein (VSG) in the bloodstream (mammalian) form. In trypanosomes, the regulation of gene expression is effected mainly at posttranscriptional levels, since primary transcription of most of the genes occurs in long polycistronic units and is constitutive. The transcripts are processed by transsplicing and polyadenylation under the influence of intergenic polypyrimidine tracts. These events show some developmental regulation. Untranslated sequences of the mRNAs seem to play a prominent role in the stage-specific control of individual gene expression, through a modulation of mRNA abundance. The VSG and procyclin transcription units exhibit particular features that are probably related to the need for a high level of expression. The promoters and RNA polymerase driving the expression of these units resemble those of the ribosomal genes. Their mutually exclusive expression is ensured by controls operating at several levels, including RNA elongation. Antigenic variation in the bloodstream is achieved through DNA rearrangements or alternative activation of the telomeric VSG gene expression sites. Recent discoveries, such as the existence of a novel nucleotide in telomeric DNA and the generation of point mutations in VSG genes, have shed new light on the mechanisms and consequences of antigenic variation. PMID:7603410

  17. Resource Sharing Controls Gene Expression Bursting.

    PubMed

    Caveney, Patrick M; Norred, S Elizabeth; Chin, Charles W; Boreyko, Jonathan B; Razooky, Brandon S; Retterer, Scott T; Collier, C Patrick; Simpson, Michael L

    2017-02-17

    Episodic gene expression, with periods of high expression separated by periods of no expression, is a pervasive biological phenomenon. This bursty pattern of expression draws from a finite reservoir of expression machinery in a highly time variant way, i.e., requiring no resources most of the time but drawing heavily on them during short intense bursts, that intimately links expression bursting and resource sharing. Yet, most recent investigations have focused on specific molecular mechanisms intrinsic to the bursty behavior of individual genes, while little is known about the interplay between resource sharing and global expression bursting behavior. Here, we confine Escherichia coli cell extract in both cell-sized microfluidic chambers and lipid-based vesicles to explore how resource sharing influences expression bursting. Interestingly, expression burst size, but not burst frequency, is highly sensitive to the size of the shared transcription and translation resource pools. The intriguing implication of these results is that expression bursts are more readily amplified than initiated, suggesting that burst formation occurs through positive feedback or cooperativity. When extrapolated to prokaryotic cells, these results suggest that large translational bursts may be correlated with large transcriptional bursts. This correlation is supported by recently reported transcription and translation bursting studies in E. coli. The results reported here demonstrate a strong intimate link between global expression burst patterns and resource sharing, and they suggest that bursting plays an important role in optimizing the use of limited, shared expression resources.

  18. Application of multidisciplinary analysis to gene expression.

    SciTech Connect

    Wang, Xuefel; Kang, Huining; Fields, Chris; Cowie, Jim R.; Davidson, George S.; Haaland, David Michael; Sibirtsev, Valeriy; Mosquera-Caro, Monica P.; Xu, Yuexian; Martin, Shawn Bryan; Helman, Paul; Andries, Erik; Ar, Kerem; Potter, Jeffrey; Willman, Cheryl L.; Murphy, Maurice H.

    2004-01-01

    Molecular analysis of cancer, at the genomic level, could lead to individualized patient diagnostics and treatments. The developments to follow will signal a significant paradigm shift in the clinical management of human cancer. Despite our initial hopes, however, it seems that simple analysis of microarray data cannot elucidate clinically significant gene functions and mechanisms. Extracting biological information from microarray data requires a complicated path involving multidisciplinary teams of biomedical researchers, computer scientists, mathematicians, statisticians, and computational linguists. The integration of the diverse outputs of each team is the limiting factor in the progress to discover candidate genes and pathways associated with the molecular biology of cancer. Specifically, one must deal with sets of significant genes identified by each method and extract whatever useful information may be found by comparing these different gene lists. Here we present our experience with such comparisons, and share methods developed in the analysis of an infant leukemia cohort studied on Affymetrix HG-U95A arrays. In particular, spatial gene clustering, hyper-dimensional projections, and computational linguistics were used to compare different gene lists. In spatial gene clustering, different gene lists are grouped together and visualized on a three-dimensional expression map, where genes with similar expressions are co-located. In another approach, projections from gene expression space onto a sphere clarify how groups of genes can jointly have more predictive power than groups of individually selected genes. Finally, online literature is automatically rearranged to present information about genes common to multiple groups, or to contrast the differences between the lists. The combination of these methods has improved our understanding of infant leukemia. While the complicated reality of the biology dashed our initial, optimistic hopes for simple answers from

  19. Modeling gene expression in time and space.

    PubMed

    Rué, Pau; Garcia-Ojalvo, Jordi

    2013-01-01

    Cell populations rarely exhibit gene-expression profiles that are homogeneous in time and space. In the temporal domain, dynamical behaviors such as oscillations and pulses of protein production pervade cell biology, underlying phenomena as diverse as circadian rhythmicity, cell cycle control, stress and damage responses, and stem-cell pluripotency. In multicellular populations, spatial heterogeneities are crucial for decision making and development, among many other functions. Cells need to exquisitely coordinate this temporal and spatial variation to survive. Although the spatiotemporal character of gene expression is challenging to quantify experimentally at the level of individual cells, it is beneficial from the modeling viewpoint, because it provides strong constraints that can be probed by theoretically analyzing mathematical models of candidate gene and protein circuits. Here, we review recent examples of temporal dynamics and spatial patterning in gene expression to show how modeling such phenomenology can help us unravel the molecular mechanisms of cellular function.

  20. Chemically regulated gene expression in plants.

    PubMed

    Padidam, Malla

    2003-04-01

    Chemically inducible systems that activate or inactivate gene expression have many potential applications in the determination of gene function and in plant biotechnology. The precise timing and control of gene expression are important aspects of chemically inducible systems. Several systems have been developed and used to analyze gene function, marker-free plant transformation, site-specific DNA excision, activation tagging, conditional genetic complementation, and restoration of male fertility. Chemicals that are used to regulate transgene expression include the antibiotic tetracycline, the steroids dexamethasone and estradiol, copper, ethanol, the inducer of pathogen-related proteins benzothiadiazol, herbicide safeners, and the insecticide methoxyfenozide. Systems that are suitable for field application are particularly useful for experimental systems and have potential applications in biotechnology.

  1. CIRCADIAN CLOCK AND CELL CYCLE GENE EXPRESSION

    PubMed Central

    Metz, Richard P.; Qu, Xiaoyu; Laffin, Brian; Earnest, David; Porter, Weston W.

    2009-01-01

    Mouse mammary epithelial cells (HC-11) and mammary tissues were analyzed for developmental changes in circadian clock, cellular proliferation and differentiation marker genes. Expression of the clock genes, Per1 and Bmal1, were elevated in differentiated HC-11 cells whereas Per2 mRNA levels were higher in undifferentiated cells. This differentiation-dependent profile of clock gene expression was consistent with that observed in mouse mammary glands as Per1 and Bmal1 mRNA levels were elevated in late pregnant and lactating mammary tissues, while Per2 expression was higher in proliferating virgin and early pregnant glands. In both HC-11 cells and mammary glands, elevated Per2 expression was positively correlated with c-Myc and Cyclin D1 mRNA levels while Per1 and Bmal1 expression changed in conjunction with ß-casein mRNA levels. Interestingly, developmental stage had differential effects on rhythms of clock gene expression in the mammary gland. These data suggest that circadian clock genes may play a role in mouse mammary gland development and differentiation. PMID:16261617

  2. Paternally expressed genes predominate in the placenta.

    PubMed

    Wang, Xu; Miller, Donald C; Harman, Rebecca; Antczak, Douglas F; Clark, Andrew G

    2013-06-25

    The discovery of genomic imprinting through studies of manipulated mouse embryos indicated that the paternal genome has a major influence on placental development. However, previous research has not demonstrated paternal bias in imprinted genes. We applied RNA sequencing to trophoblast tissue from reciprocal hybrids of horse and donkey, where genotypic differences allowed parent-of-origin identification of most expressed genes. Using this approach, we identified a core group of 15 ancient imprinted genes, of which 10 were paternally expressed. An additional 78 candidate imprinted genes identified by RNA sequencing also showed paternal bias. Pyrosequencing was used to confirm the imprinting status of six of the genes, including the insulin receptor (INSR), which may play a role in growth regulation with its reciprocally imprinted ligand, histone acetyltransferase-1 (HAT1), a gene involved in chromatin modification, and lymphocyte antigen 6 complex, locus G6C, a newly identified imprinted gene in the major histocompatibility complex. The 78 candidate imprinted genes displayed parent-of-origin expression bias in placenta but not fetus, and most showed less than 100% silencing of the imprinted allele. Some displayed variability in imprinting status among individuals. This variability results in a unique epigenetic signature for each placenta that contributes to variation in the intrauterine environment and thus presents the opportunity for natural selection to operate on parent-of-origin differential regulation. Taken together, these features highlight the plasticity of imprinting in mammals and the central importance of the placenta as a target tissue for genomic imprinting.

  3. Hepatic Xenobiotic Metabolizing Enzyme Gene Expression ...

    EPA Pesticide Factsheets

    BACKGROUND: Differences in responses to environmental chemicals and drugs between life stages are likely due in part to differences in the expression of xenobiotic metabolizing enzymes and transporters (XMETs). No comprehensive analysis of the mRNA expression of XMETs has been carried out through life stages in any species. RESULTS: Using full-genome arrays, the mRNA expression of all XMETs and their regulatory proteins was examined during fetal (gestation day (GD) 19), neonatal (postnatal day (PND) 7), prepubescent (PND32), middle age (12 months), and old age (18 and 24 months) in the C57BL/6J (C57) mouse liver and compared to adults. Fetal and neonatal life stages exhibited dramatic differences in XMET mRNA expression compared to the relatively minor effects of old age. The total number of XMET probe sets that differed from adults was 636, 500, 84, 5, 43, and 102 for GD19, PND7, PND32, 12 months, 18 months and 24 months, respectively. At all life stages except PND32, under-expressed genes outnumbered over-expressed genes. The altered XMETs included those in all of the major metabolic and transport phases including introduction of reactive or polar groups (Phase I), conjugation (Phase II) and excretion (Phase III). In the fetus and neonate, parallel increases in expression were noted in the dioxin receptor, Nrf2 components and their regulated genes while nuclear receptors and regulated genes were generally down-regulated. Suppression of male-specific XMETs w

  4. Zearalenone activates pregnane X receptor, constitutive androstane receptor and aryl hydrocarbon receptor and corresponding phase I target genes mRNA in primary cultures of human hepatocytes.

    PubMed

    Ayed-Boussema, Imen; Pascussi, Jean Marc; Maurel, Patrick; Bacha, Hassen; Hassen, Wafa

    2011-01-01

    The mycotoxin zearalenone (ZEN) is found worldwide as a contaminant in cereals and grains. ZEN subchronic and chronic toxicities are dominated by reproductive disorders in different mammalian species which have made ZEN established mammalian endocrine disrupter. Over the last 30 years of ZEN biotransformation study, the toxin was thought to undergo reductive metabolism only, with the generation in several species of α- and β-isomers of zearalenol. However, recent investigations have noticed that the mycoestrogen is prone to oxidative metabolism leading to hydroxylation of ZEN though the involvement of different cytochromes P450 (CYPs) isoforms. The aim of the present study was to further explore the effect of ZEN on regulation of some CYPs using primary cultures of human hepatocytes. For this aim, using real time RT-PCR, we monitored in a first time, the effect of ZEN on mRNA levels of pregnane X receptor (PXR), constitutive androstane receptor (CAR) and aryl hydrocarbon receptor (AhR), nuclear receptors known to be involved in the regulation of some CYPs. In a second time, we looked for ZEN effect on expression of PXR, CAR and AhR corresponding phase I target genes (CYP3A4, CYP3A5, CYP2B6, CYP2C9, CYP1A1 and CYP1A2). Finally, we realised the luciferase assay in HepG2 treated with the toxin and transiently transfected with p-CYP3A4-Luc in the presence of a hPXR vector or transfected with p-CYPA1-Luc.Our results clearly showed that ZEN activated human PXR, CAR and AhR mRNA levels in addition to some of their phase I target genes mainly CYP3A4, CYP2B6 and CYP1A1 and at lesser extent CYP3A5 and CYP2C9 at ZEN concentrations as low as 0.1 μM.

  5. The Mitochondria-Targeted Antioxidant SkQ1 Downregulates Aryl Hydrocarbon Receptor-Dependent Genes in the Retina of OXYS Rats with AMD-Like Retinopathy

    PubMed Central

    Perepechaeva, M. L.; Grishanova, A. Yu.; Rudnitskaya, E. A.; Kolosova, N. G.

    2014-01-01

    The mitochondria-targeted antioxidant SkQ1 is a novel drug thought to retard development of age-related diseases. It has been shown that SkQ1 reduces clinical signs of retinopathy in senescence-accelerated OXYS rats, which are a known animal model of human age-related macular degeneration (AMD). The aim of this work was to test whether SkQ1 affects transcriptional activity of AhR (aryl hydrocarbon receptor) and Nrf2 (nuclear factor erythroid 2-related factor 2), which are considered as AMD-associated genes in the retina of OXYS and Wistar rats. Our results showed that only AhR and AhR-dependent genes were sensitive to SkQ1. Dietary supplementation with SkQ1 decreased the AhR mRNA level in both OXYS and Wistar rats. At baseline, the retinal Cyp1a1 mRNA level was lower in OXYS rats. SkQ1 supplementation decreased the Cyp1a1 mRNA level in Wistar rats, but this level remained unchanged in OXYS rats. Baseline Cyp1a2 and Cyp1b1 mRNA expression was stronger in OXYS than in Wistar rats. In the OXYS strain, Cyp1a2 and Cyp1b1 mRNA levels decreased as a result of SkQ1 supplementation. These data suggest that the Cyp1a2 and Cyp1b1 enzymes are involved in the pathogenesis of AMD-like retinopathy of OXYS rats and are possible therapeutic targets of SkQ1. PMID:25132985

  6. Three gene expression vector sets for concurrently expressing multiple genes in Saccharomyces cerevisiae.

    PubMed

    Ishii, Jun; Kondo, Takashi; Makino, Harumi; Ogura, Akira; Matsuda, Fumio; Kondo, Akihiko

    2014-05-01

    Yeast has the potential to be used in bulk-scale fermentative production of fuels and chemicals due to its tolerance for low pH and robustness for autolysis. However, expression of multiple external genes in one host yeast strain is considerably labor-intensive due to the lack of polycistronic transcription. To promote the metabolic engineering of yeast, we generated systematic and convenient genetic engineering tools to express multiple genes in Saccharomyces cerevisiae. We constructed a series of multi-copy and integration vector sets for concurrently expressing two or three genes in S. cerevisiae by embedding three classical promoters. The comparative expression capabilities of the constructed vectors were monitored with green fluorescent protein, and the concurrent expression of genes was monitored with three different fluorescent proteins. Our multiple gene expression tool will be helpful to the advanced construction of genetically engineered yeast strains in a variety of research fields other than metabolic engineering.

  7. Expression of myriapod pair rule gene orthologs

    PubMed Central

    2011-01-01

    Background Segmentation is a hallmark of the arthropods; most knowledge about the molecular basis of arthropod segmentation comes from work on the fly Drosophila melanogaster. In this species a hierarchic cascade of segmentation genes subdivides the blastoderm stepwise into single segment wide regions. However, segmentation in the fly is a derived feature since all segments form virtually simultaneously. Conversely, in the vast majority of arthropods the posterior segments form one at a time from a posterior pre-segmental zone. The pair rule genes (PRGs) comprise an important level of the Drosophila segmentation gene cascade and are indeed the first genes that are expressed in typical transverse stripes in the early embryo. Information on expression and function of PRGs outside the insects, however, is scarce. Results Here we present the expression of the pair rule gene orthologs in the pill millipede Glomeris marginata (Myriapoda: Diplopoda). We find evidence that these genes are involved in segmentation and that components of the hierarchic interaction of the gene network as found in insects may be conserved. We further provide evidence that segments are formed in a single-segment periodicity rather than in pairs of two like in another myriapod, the centipede Strigamia maritima. Finally we show that decoupling of dorsal and ventral segmentation in Glomeris appears already at the level of the PRGs. Conclusions Although the pair rule gene network is partially conserved among insects and myriapods, some aspects of PRG interaction are, as suggested by expression pattern analysis, convergent, even within the Myriapoda. Conserved expression patterns of PRGs in insects and myriapods, however, may represent ancestral features involved in segmenting the arthropod ancestor. PMID:21352542

  8. Human AZU-1 gene, variants thereof and expressed gene products

    DOEpatents

    Chen, Huei-Mei; Bissell, Mina

    2004-06-22

    A human AZU-1 gene, mutants, variants and fragments thereof. Protein products encoded by the AZU-1 gene and homologs encoded by the variants of AZU-1 gene acting as tumor suppressors or markers of malignancy progression and tumorigenicity reversion. Identification, isolation and characterization of AZU-1 and AZU-2 genes localized to a tumor suppressive locus at chromosome 10q26, highly expressed in nonmalignant and premalignant cells derived from a human breast tumor progression model. A recombinant full length protein sequences encoded by the AZU-1 gene and nucleotide sequences of AZU-1 and AZU-2 genes and variant and fragments thereof. Monoclonal or polyclonal antibodies specific to AZU-1, AZU-2 encoded protein and to AZU-1, or AZU-2 encoded protein homologs.

  9. Rubisco gene expression in C4 plants.

    PubMed

    Patel, Minesh; Berry, James O

    2008-01-01

    In leaves of most C(4) plants, ribulose 1,5 bisphosphate carboxylase (Rubisco) accumulates only in bundle sheath (bs) cells that surround the vascular centres, and not in mesophyll (mp) cells. It has been shown previously that in the C(4) dicots amaranth and Flaveria bidentis, post-transcriptional control of mRNA translation and stability mediate the C(4) expression patterns of genes encoding the large and small Rubisco subunits (chloroplast rbcL and nuclear RbcS, respectively). Translational control appears to regulate bs cell-specific Rubisco gene expression during early dicot leaf development, while control of mRNA stability appears to mediate bs-specific accumulation of RbcS and rbcL transcripts in mature leaves. Post-transcriptional control is also involved in the regulation of Rubisco gene expression by light, and in response to photosynthetic activity. Transgenic and transient expression studies in F. bidentis provide direct evidence for post-transcriptional control of bs cell-specific RbcS expression, which is mediated by the 5' and 3' untranslated regions (UTRs) of the mRNA. Comparisons of Rubisco gene expression in these dicots and in the monocot maize indicates possible commonalities in the regulation of RbcS and rbcL genes in these divergent C(4) species. Now that the role of post-transcriptional regulation in C(4) gene expression has been established, it is likely that future studies of mRNA-protein interactions will address long-standing questions about the establishment and maintenance of cell type-specificity in these plants. Some of these regulatory mechanisms may have ancestral origins in C(3) species, through modification of pre-existing factors, or by the acquisition of novel C(4) processes.

  10. Mixed-ligand copper(II) complexes activate aryl hydrocarbon receptor AhR and induce CYP1A genes expression in human hepatocytes and human cell lines.

    PubMed

    Kubešová, Kateřina; Dořičáková, Aneta; Trávníček, Zdeněk; Dvořák, Zdeněk

    2016-07-25

    The effects of four copper(II) mixed-ligand complexes [Cu(qui1)(L)]NO3·H2O (1-3) and [Cu(qui2)(phen)]NO3 (4), where qui1=2-phenyl-3-hydroxy-4(1H)-quinolinone, Hqui2=2-(4-amino-3,5-dichlorophenyl)-N-propyl-3-hydroxy-4(1H)-quinolinone-7-carboxamide, L=1,10-phenanthroline (phen) (1), 5-methyl-1,10-phenanthroline (mphen) (2), bathophenanthroline (bphen) (3), on transcriptional activities of steroid receptors, nuclear receptors and xenoreceptors have been studied. The complexes (1-4) did not influence basal or ligand-inducible activities of glucocorticoid receptor, androgen receptor, thyroid receptor, pregnane X receptor and vitamin D receptor, as revealed by gene reporter assays. The complexes 1 and 2 dose-dependently induced luciferase activity in stable gene reporter AZ-AhR cell line, and this induction was reverted by resveratrol, indicating involvement of aryl hydrocarbon receptor (AhR) in the process. The complexes 1, 2 and 3 induced CYP1A1 mRNA in LS180 cells and CYP1A1/CYP1A2 in human hepatocytes through AhR. Electrophoretic mobility shift assay EMSA showed that the complexes 1 and 2 transformed AhR in its DNA-binding form. Collectively, we demonstrate that the complexes 1 and 2 activate AhR and induce AhR-dependent genes in human hepatocytes and cancer cell lines. In conclusion, the data presented here might be of toxicological importance, regarding the multiple roles of AhR in human physiology and pathophysiology.

  11. Alternative-splicing-mediated gene expression

    NASA Astrophysics Data System (ADS)

    Wang, Qianliang; Zhou, Tianshou

    2014-01-01

    Alternative splicing (AS) is a fundamental process during gene expression and has been found to be ubiquitous in eukaryotes. However, how AS impacts gene expression levels both quantitatively and qualitatively remains to be fully explored. Here, we analyze two common models of gene expression, each incorporating a simple splice mechanism that a pre-mRNA is spliced into two mature mRNA isoforms in a probabilistic manner. In the constitutive expression case, we show that the steady-state molecular numbers of two mature mRNA isoforms follow mutually independent Poisson distributions. In the bursting expression case, we demonstrate that the tail decay of the steady-state distribution for both mature mRNA isoforms that in general are not mutually independent can be characterized by the product of mean burst size and splicing probability. In both cases, we find that AS can efficiently modulate both the variability (measured by variance) and the noise level of the total mature mRNA, and in particular, the latter is always lower than the noise level of the pre-mRNA, implying that AS always reduces the noise. These results altogether reveal that AS is a mechanism of efficiently controlling the gene expression noise.

  12. Age-related changes in microRNA expression and pharmacogenes in human liver

    PubMed Central

    Burgess, Kimberly S.; Philips, Santosh; Benson, Eric A.; Desta, Zeruesenay; Gaedigk, Andrea; Gaedigk, Roger; Segar, Matthew W.; Liu, Yunlong; Skaar, Todd C.

    2015-01-01

    Developmental changes in the liver can significantly impact drug disposition. Due to the emergence of microRNAs (miRNAs) as important regulators of drug disposition gene expression, we studied age-dependent changes in miRNA expression. Expression of 533 miRNAs was measured in 90 human liver tissues (fetal, pediatric (1-17 years), and adult (28-80 years); n=30 each). 114 miRNAs were upregulated and 72 were downregulated from fetal to pediatric, and 2 and 3, respectively, from pediatric to adult. Among the developmentally changing miRNAs, 99 miRNA-mRNA interactions were predicted or experimentally validated (e.g. hsamiR-125b-5p-CYP1A1; hsa-miR-34a-5p-HNF4A). In human liver samples (n=10 each), analyzed by RNA-sequencing, significant negative correlations were observed between the expression of >1000 miRNAs and mRNAs of drug disposition and regulatory genes. Our data suggest a mechanism for the marked changes in hepatic gene expression between the fetal and pediatric developmental periods, and support a role for these age-dependent miRNAs in regulating drug disposition. PMID:25968989

  13. Gene expression profiles in irradiated cancer cells

    NASA Astrophysics Data System (ADS)

    Minafra, L.; Bravatà, V.; Russo, G.; Ripamonti, M.; Gilardi, M. C.

    2013-07-01

    Knowledge of the molecular and genetic mechanisms underlying cellular response to radiation may provide new avenues to develop innovative predictive tests of radiosensitivity of tumours and normal tissues and to improve individual therapy. Nowadays very few studies describe molecular changes induced by hadrontherapy treatments, therefore this field has to be explored and clarified. High-throughput methodologies, such as DNA microarray, allow us to analyse mRNA expression of thousands of genes simultaneously in order to discover new genes and pathways as targets of response to hadrontherapy. Our aim is to elucidate the molecular networks involved in the sensitivity/resistance of cancer cell lines subjected to hadrontherapy treatments with a genomewide approach by using cDNA microarray technology to identify gene expression profiles and candidate genes responsible of differential cellular responses.

  14. Gene expression profiles in irradiated cancer cells

    SciTech Connect

    Minafra, L.; Bravatà, V.; Russo, G.; Ripamonti, M.; Gilardi, M. C.

    2013-07-26

    Knowledge of the molecular and genetic mechanisms underlying cellular response to radiation may provide new avenues to develop innovative predictive tests of radiosensitivity of tumours and normal tissues and to improve individual therapy. Nowadays very few studies describe molecular changes induced by hadrontherapy treatments, therefore this field has to be explored and clarified. High-throughput methodologies, such as DNA microarray, allow us to analyse mRNA expression of thousands of genes simultaneously in order to discover new genes and pathways as targets of response to hadrontherapy. Our aim is to elucidate the molecular networks involved in the sensitivity/resistance of cancer cell lines subjected to hadrontherapy treatments with a genomewide approach by using cDNA microarray technology to identify gene expression profiles and candidate genes responsible of differential cellular responses.

  15. Maternal cigarette smoking, metabolic gene polymorphisms, and preterm delivery: new insights on G×E interactions and pathogenic pathways

    PubMed Central

    Liu, Xin; Mestan, Karen; Yu, Yunxian; Zhang, Shanchun; Fang, Yaping; Pearson, Colleen; Ortiz, Katherin; Zuckerman, Barry; Bauchner, Howard; Cerda, Sandra; Stubblefield, Phillip G.; Xu, Xiping; Wang, Xiaobin

    2010-01-01

    Preterm delivery (PTD, <37 weeks of gestation) is a significant clinical and public health problem. Previously, we reported that maternal smoking and metabolic gene polymorphisms of CYP1A1 MspI and GSTT1 synergistically increase the risk of low birth weight. This study investigates the relationship between maternal smoking and metabolic gene polymorphisms of CYP1A1 MspI and GSTT1 with preterm delivery (PTD) as a whole and pre-term subgroups. This case–control study included 1,749 multi-ethnic mothers (571 with PTD and 1,178 controls) enrolled at Boston Medical Center. After adjusting covariates, regression analyses were performed to identify individual and joint associations of maternal smoking, two functional variants of CYP1A1 and GSTT1 with PTD. We observed a moderate effect of maternal smoking on PTD (OR = 1.6; 95% CI: 1.1–2.2). We found that compared to non-smoking mothers with low-risk genotypes, there was a significant joint association of maternal smoking, CYP1A1 (Aa/aa) and GSTT1 (absent) genotypes with gestational age (β = −3.37; SE = 0.86; P = 9 × 10−5) and with PTD (OR = 5.8; 95% CI: 2.0–21.1), respectively. Such joint association was particularly strong in certain preterm subgroups, including spontaneous PTD (OR = 8.3; 95% CI: 2.7–30.6), PTD < 32 weeks (OR = 11.1; 95% CI: 2.9–47.7), and PTD accompanied by histologic chorioamnionitis (OR = 15.6; 95% CI: 4.1–76.7). Similar patterns were observed across ethnic groups. Taken together, maternal smoking significantly increased the risk of PTD among women with high-risk CYP1A1 and GSTT1 genotypes. Such joint associations were strongest among PTD accompanied by histologic chorioamnionitis. PMID:18320229

  16. Maternal cigarette smoking, metabolic gene polymorphisms, and preterm delivery: new insights on GxE interactions and pathogenic pathways.

    PubMed

    Tsai, Hui-Ju; Liu, Xin; Mestan, Karen; Yu, Yunxian; Zhang, Shanchun; Fang, Yaping; Pearson, Colleen; Ortiz, Katherin; Zuckerman, Barry; Bauchner, Howard; Cerda, Sandra; Stubblefield, Phillip G; Xu, Xiping; Wang, Xiaobin

    2008-05-01

    Preterm delivery (PTD, <37 weeks of gestation) is a significant clinical and public health problem. Previously, we reported that maternal smoking and metabolic gene polymorphisms of CYP1A1 MspI and GSTT1 synergistically increase the risk of low birth weight. This study investigates the relationship between maternal smoking and metabolic gene polymorphisms of CYP1A1 MspI and GSTT1 with preterm delivery (PTD) as a whole and preterm subgroups. This case-control study included 1,749 multi-ethnic mothers (571 with PTD and 1,178 controls) enrolled at Boston Medical Center. After adjusting covariates, regression analyses were performed to identify individual and joint associations of maternal smoking, two functional variants of CYP1A1 and GSTT1 with PTD. We observed a moderate effect of maternal smoking on PTD (OR = 1.6; 95% CI: 1.1-2.2). We found that compared to non-smoking mothers with low-risk genotypes, there was a significant joint association of maternal smoking, CYP1A1 (Aa/aa) and GSTT1 (absent) genotypes with gestational age (beta = -3.37; SE = 0.86; P = 9 x 10(-5)) and with PTD (OR = 5.8; 95% CI: 2.0-21.1), respectively. Such joint association was particularly strong in certain preterm subgroups, including spontaneous PTD (OR = 8.3; 95% CI: 2.7-30.6), PTD < 32 weeks (OR = 11.1; 95% CI: 2.9-47.7), and PTD accompanied by histologic chorioamnionitis (OR = 15.6; 95% CI: 4.1-76.7). Similar patterns were observed across ethnic groups. Taken together, maternal smoking significantly increased the risk of PTD among women with high-risk CYP1A1 and GSTT1 genotypes. Such joint associations were strongest among PTD accompanied by histologic chorioamnionitis.

  17. Visualizing Gene Expression In Situ

    SciTech Connect

    Burlage, R.S.

    1998-11-02

    Visualizing bacterial cells and describing their responses to the environment are difficult tasks. Their small size is the chief reason for the difficulty, which means that we must often use many millions of cells in a sample in order to determine what the average response of the bacteria is. However, an average response can sometimes mask important events in bacterial physiology, which means that our understanding of these organisms will suffer. We have used a variety of instruments to visualize bacterial cells, all of which tell us something different about the sample. We use a fluorescence activated cell sorter to sort cells based on the fluorescence provided by bioreporter genes, and these can be used to select for particular genetic mutations. Cells can be visualized by epifluorescent microscopy, and sensitive photodetectors can be added that allow us to find a single bacterial cell that is fluorescent or bioluminescent. We have also used standard photomultipliers to examine cell aggregates as field bioreporter microorganisms. Examples of each of these instruments show how our understanding of bacterial physiology has changed with the technology.

  18. Gene expression profile in pelvic organ prolapse†

    PubMed Central

    Brizzolara, S.S.; Killeen, J.; Urschitz, J.

    2009-01-01

    It was hypothesized that the processes contributing to pelvic organ prolapse (POP) may be identified by transcriptional profiling of pelvic connective tissue in conjunction with light microscopy. In order to test this, we performed a frequency-matched case–control study of women undergoing hysterectomy for POP and controls. Total RNA, extracted from uterosacral and round ligament samples used to generate labeled cRNA, was hybridized to microarrays and analyzed for the expression of 32 878 genes. Significance Analysis of Microarrays (Stanford University, CA, USA) identified differentially expressed genes used for ontoanalysis. Quantitative PCR (qPCR) confirmed results. Light microscopy confirmed the tissue type and assessed inflammatory infiltration. The analysis of 34 arrays revealed 249 differentially expressed genes with fold changes (FC) larger than 1.5 and false discovery rates ≤5.2%. Immunity and defense was the most significant biological process differentially expressed in POP. qPCR confirmed the elevated steady-state mRNA levels for four genes: interleukin-6 (FC 9.8), thrombospondin 1 (FC 3.5) and prostaglandin-endoperoxide synthase 2 (FC 2.4) and activating transcription factor 3 (FC 2.6). Light microscopy showed all the samples were composed of fibromuscular connective tissue with no inflammatory infiltrates. In conclusion, genes enriched for ‘immunity and defense’ contribute to POP independent of inflammatory infiltrates. PMID:19056808

  19. Clustering of High Throughput Gene Expression Data

    PubMed Central

    Pirim, Harun; Ekşioğlu, Burak; Perkins, Andy; Yüceer, Çetin

    2012-01-01

    High throughput biological data need to be processed, analyzed, and interpreted to address problems in life sciences. Bioinformatics, computational biology, and systems biology deal with biological problems using computational methods. Clustering is one of the methods used to gain insight into biological processes, particularly at the genomics level. Clearly, clustering can be used in many areas of biological data analysis. However, this paper presents a review of the current clustering algorithms designed especially for analyzing gene expression data. It is also intended to introduce one of the main problems in bioinformatics - clustering gene expression data - to the operations research community. PMID:23144527

  20. Facilitated diffusion buffers noise in gene expression.

    PubMed

    Schoech, Armin P; Zabet, Nicolae Radu

    2014-09-01

    Transcription factors perform facilitated diffusion [three-dimensional (3D) diffusion in the cytosol and 1D diffusion on the DNA] when binding to their target sites to regulate gene expression. Here, we investigated the influence of this binding mechanism on the noise in gene expression. Our results showed that, for biologically relevant parameters, the binding process can be represented by a two-state Markov model and that the accelerated target finding due to facilitated diffusion leads to a reduction in both the mRNA and the protein noise.

  1. Facilitated diffusion buffers noise in gene expression

    NASA Astrophysics Data System (ADS)

    Schoech, Armin P.; Zabet, Nicolae Radu

    2014-09-01

    Transcription factors perform facilitated diffusion [three-dimensional (3D) diffusion in the cytosol and 1D diffusion on the DNA] when binding to their target sites to regulate gene expression. Here, we investigated the influence of this binding mechanism on the noise in gene expression. Our results showed that, for biologically relevant parameters, the binding process can be represented by a two-state Markov model and that the accelerated target finding due to facilitated diffusion leads to a reduction in both the mRNA and the protein noise.

  2. Objective and subjective probability in gene expression.

    PubMed

    Velasco, Joel D

    2012-09-01

    In this paper I address the question of whether the probabilities that appear in models of stochastic gene expression are objective or subjective. I argue that while our best models of the phenomena in question are stochastic models, this fact should not lead us to automatically assume that the processes are inherently stochastic. After distinguishing between models and reality, I give a brief introduction to the philosophical problem of the interpretation of probability statements. I argue that the objective vs. subjective distinction is a false dichotomy and is an unhelpful distinction in this case. Instead, the probabilities in our models of gene expression exhibit standard features of both objectivity and subjectivity.

  3. Genomic signatures of germline gene expression.

    PubMed

    McVicker, Graham; Green, Phil

    2010-11-01

    Transcribed regions in the human genome differ from adjacent intergenic regions in transposable element density, crossover rates, and asymmetric substitution and sequence composition patterns. We tested whether these differences reflect selection or are instead a byproduct of germline transcription, using publicly available gene expression data from a variety of germline and somatic tissues. Crossover rate shows a strong negative correlation with gene expression in meiotic tissues, suggesting that crossover is inhibited by transcription. Strand-biased composition (G+T content) and A → G versus T → C substitution asymmetry are both positively correlated with germline gene expression. We find no evidence for a strand bias in allele frequency data, implying that the substitution asymmetry reflects a mutation rather than a fixation bias. The density of transposable elements is positively correlated with germline expression, suggesting that such elements preferentially insert into regions that are actively transcribed. For each of the features examined, our analyses favor a nonselective explanation for the observed trends and point to the role of germline gene expression in shaping the mammalian genome.

  4. [Imprinting genes and it's expression in Arabidopsis].

    PubMed

    Zhang, Hong-Yu; Xu, Pei-Zhou; Yang, Hua; Wu, Xian-Jun

    2010-07-01

    Genomic imprinting refers to the phenomenon that the expression of a gene copy depends on its parent of origin. The Arabidopsis imprinted FIS (Fertilisation-independent seed) genes, mea, fis2, and fie, play essential roles in the repression of central cell and the regulation of early endosperm development. fis mutants display two phenotypes: autonomous diploid endosperm development when fertilization is absent and un-cellularised endosperm formation when fertilization occurs. The FIS Polycomb protein complex including the above three FIS proteins catalyzes histone H3 K27 tri-methylation on target loci. DME (DEMETER), a DNA glycosylase, and AtMET1 (Methyltransferase1), a DNA methyltransferase, are involved in the regulation of imprinted expression of both mea and fis2. This review summarizes the studies on the Arabidopsis imprinted FIS genes and other related genes. Recent works have shown that the insertion of transposons may affect nearby gene expression, which may be the main driving force behind the evolution of genomic imprinting. This summary covers the achievements on Arabidopsis imprinted genes will provide important information for studies on genomic imprinting in the important crops such as rice and maize.

  5. Sequence and gene expression evolution of paralogous genes in willows

    PubMed Central

    Harikrishnan, Srilakshmy L.; Pucholt, Pascal; Berlin, Sofia

    2015-01-01

    Whole genome duplications (WGD) have had strong impacts on species diversification by triggering evolutionary novelties, however, relatively little is known about the balance between gene loss and forces involved in the retention of duplicated genes originating from a WGD. We analyzed putative Salicoid duplicates in willows, originating from the Salicoid WGD, which took place more than 45 Mya. Contigs were constructed by de novo assembly of RNA-seq data derived from leaves and roots from two genotypes. Among the 48,508 contigs, 3,778 pairs were, based on fourfold synonymous third-codon transversion rates and syntenic positions, predicted to be Salicoid duplicates. Both copies were in most cases expressed in both tissues and 74% were significantly differentially expressed. Mean Ka/Ks was 0.23, suggesting that the Salicoid duplicates are evolving by purifying selection. Gene Ontology enrichment analyses showed that functions related to DNA- and nucleic acid binding were over-represented among the non-differentially expressed Salicoid duplicates, while functions related to biosynthesis and metabolism were over-represented among the differentially expressed Salicoid duplicates. We propose that the differentially expressed Salicoid duplicates are regulatory neo- and/or subfunctionalized, while the non-differentially expressed are dose sensitive, hence, functionally conserved. Multiple evolutionary processes, thus drive the retention of Salicoid duplicates in willows. PMID:26689951

  6. Sequence and gene expression evolution of paralogous genes in willows.

    PubMed

    Harikrishnan, Srilakshmy L; Pucholt, Pascal; Berlin, Sofia

    2015-12-22

    Whole genome duplications (WGD) have had strong impacts on species diversification by triggering evolutionary novelties, however, relatively little is known about the balance between gene loss and forces involved in the retention of duplicated genes originating from a WGD. We analyzed putative Salicoid duplicates in willows, originating from the Salicoid WGD, which took place more than 45 Mya. Contigs were constructed by de novo assembly of RNA-seq data derived from leaves and roots from two genotypes. Among the 48,508 contigs, 3,778 pairs were, based on fourfold synonymous third-codon transversion rates and syntenic positions, predicted to be Salicoid duplicates. Both copies were in most cases expressed in both tissues and 74% were significantly differentially expressed. Mean Ka/Ks was 0.23, suggesting that the Salicoid duplicates are evolving by purifying selection. Gene Ontology enrichment analyses showed that functions related to DNA- and nucleic acid binding were over-represented among the non-differentially expressed Salicoid duplicates, while functions related to biosynthesis and metabolism were over-represented among the differentially expressed Salicoid duplicates. We propose that the differentially expressed Salicoid duplicates are regulatory neo- and/or subfunctionalized, while the non-differentially expressed are dose sensitive, hence, functionally conserved. Multiple evolutionary processes, thus drive the retention of Salicoid duplicates in willows.

  7. The TRANSFAC system on gene expression regulation.

    PubMed

    Wingender, E; Chen, X; Fricke, E; Geffers, R; Hehl, R; Liebich, I; Krull, M; Matys, V; Michael, H; Ohnhäuser, R; Prüss, M; Schacherer, F; Thiele, S; Urbach, S

    2001-01-01

    The TRANSFAC database on transcription factors and their DNA-binding sites and profiles (http://www.gene-regulation.de/) has been quantitatively extended and supplemented by a number of modules. These modules give information about pathologically relevant mutations in regulatory regions and transcription factor genes (PathoDB), scaffold/matrix attached regions (S/MARt DB), signal transduction (TRANSPATH) and gene expression sources (CYTOMER). Altogether, these distinct database modules constitute the TRANSFAC system. They are accompanied by a number of program routines for identifying potential transcription factor binding sites or for localizing individual components in the regulatory network of a cell.

  8. Marker gene tethering by nucleoporins affects gene expression in plants.

    PubMed

    Smith, Sarah; Galinha, Carla; Desset, Sophie; Tolmie, Frances; Evans, David; Tatout, Christophe; Graumann, Katja

    2015-01-01

    In non-plant systems, chromatin association with the nuclear periphery affects gene expression, where interactions with nuclear envelope proteins can repress and interactions with nucleoporins can enhance transcription. In plants, both hetero- and euchromatin can localize at the nuclear periphery, but the effect of proximity to the nuclear periphery on gene expression remains largely unknown. This study explores the putative function of Seh1 and Nup50a nucleoporins on gene expression by using the Lac Operator / Lac Repressor (LacI-LacO) system adapted to Arabidopsis thaliana. We used LacO fused to the luciferase reporter gene (LacO:Luc) to investigate whether binding of the LacO:Luc transgene to nucleoporin:LacI protein fusions alters luciferase expression. Two separate nucleoporin-LacI-YFP fusions were introduced into single insert, homozygous LacO:Luc Arabidopsis plants. Homozygous plants carrying LacO:Luc and a single insert of either Seh1-LacI-YFP or Nup50a-LacI-YFP were tested for luciferase activity and compared to plants containing LacO:Luc only. Seh1-LacI-YFP increased, while Nup50a-LacI-YFP decreased luciferase activity. Seh1-LacI-YFP accumulated at the nuclear periphery as expected, while Nup50a-LacI-YFP was nucleoplasmic and was not selected for further study. Protein and RNA levels of luciferase were quantified by western blotting and RT-qPCR, respectively. Increased luciferase activity in LacO:Luc+Seh1-LacI-YFP plants was correlated with increased luciferase protein and RNA levels. This change of luciferase expression was abolished by disruption of LacI-LacO binding by treating with IPTG in young seedlings, rosette leaves and inflorescences. This study suggests that association with the nuclear periphery is involved in the regulation of gene expression in plants.

  9. Transgenic control of perforin gene expression

    SciTech Connect

    Lichtenheld, M.G.; Podack, E.R.; Levy, R.B.

    1995-03-01

    Perforin is a pore-forming effector molecule of CTL and NK cells. To characterize perforin gene expression and its transcriptional control mechanisms in vivo, expression of a cell surface tag, i.e., human CD4, was driven by 5.1 kb of the murin perforin 5{prime} flanking and promoter region in transgenic mice. Six out of seven transgenic lines expressed the perforin-tag hybrid gene at low to intermediate levels, depending on the integration site. Transgene expression occurred in all cells that physiologically are able to express perforin. At the whole organ level, significant amounts of transgenic mRNA and endogenous perforin mRNA were co-expressed in the lymphoid organs, as well as in the lung, the ileum, the oviduct/uterus, and the bone marrow. At the single cell level, the perforin tag was present on NK cells and on CD8{sup +}, as well as on CD4{sup +} cells. Also targeted were Thy-1.2{sup +} {gamma}{delta} T cells, but not Thy-1.2{sup -} {gamma}{delta} T cells, B cells, nor monocytes. During thymic T cell development, transgene expression occurred in double negative (CD4{sup -}CD8{sup -}) thymocytes and was detected at all subsequent stages, but exceeded the expression levels of the endogenous gene in the thymus. In conclusion, the analyzed perforin 5{prime} flanking and promoter region contains important cis-acting sequences that restrict perforin expression to T cells and NK cells, and therefore provides a unique tool for manipulating T cell and/or Nk cell-mediated immune responses in transgenic mice. On the other hand, the normal control of perforin gene expression involves at least one additional negative control mechanism that was not mediated by the transgenic promoter and upstream region. This control restricts perforin gene expression in thymically developing T cells and in most resting peripheral T cells, but can be released upon T cell activation. 43 refs., 7 figs., 1 tab.

  10. Organization and expression of hair follicle genes.

    PubMed

    Rogers, G E; Powell, B C

    1993-07-01

    Several families of proteins are expressed in the growth of hair and an estimated 50-100 proteins constitute the final hair fiber. The cumbersome nomenclature for naming these different proteins has led to a proposal to modify that which is currently used for epidermal keratins. Investigations of the organization of hair genes indicate that the members of each family are clustered in the genome and their expression could be under some general control. Interestingly, the protein called trichohyalin, markedly distinct from the hair proteins, is produced in the inner root sheath cells and the gene for it has been found to be located at the same human chromosome locus as the genes for profilaggrin, involucrin, and loricrin. A mainstream objective is to identify controls responsible for the production in the hair cortex of keratin intermediate filaments (IFs) and two large groups of keratin-associated proteins (KAPs) rich in the amino acids cysteine or glycine/tyrosine. A specific family of cysteine-rich proteins is expressed in the hair cuticle. Comparisons of promoter regions of IF genes and KAP genes, including a recently characterized gene for a glycine/tyrosine-rich protein, have revealed putative hair-specific motifs in addition to known elements that regulate gene expression. In the sheep, the patterns of expression in hair differentiation are particularly interesting insofar as there are distinct segments of para- and orthocortical type cells that have significantly different pathways of expression. The testing of candidate hair-specific regulatory sequences by mouse transgenesis has produced several interesting hair phenotypes. Transgenic sheep over-expressing keratin genes but showing no hair growth change have been obtained and compared with the equivalent transgenic hair-loss mice. Studies of the effects of amino acid supply on the rate of hair growth have demonstrated that with cysteine supplementation of sheep a perturbation occurs in which there is a

  11. Regulation of Calreticulin Gene Expression by Calcium

    PubMed Central

    Waser, Mathilde; Mesaeli, Nasrin; Spencer, Charlotte; Michalak, Marek

    1997-01-01

    We have isolated and characterized a 12-kb mouse genomic DNA fragment containing the entire calreticulin gene and 2.14 kb of the promoter region. The mouse calreticulin gene consists of nine exons and eight introns, and it spans 4.2 kb of genomic DNA. A 1.8-kb fragment of the calreticulin promoter was subcloned into a reporter gene plasmid containing chloramphenicol acetyltransferase. This construct was then used in transient and stable transfection of NIH/ 3T3 cells. Treatment of transfected cells either with the Ca2+ ionophore A23187, or with the ER Ca2+-ATPase inhibitor thapsigargin, resulted in a five- to sevenfold increase of the expression of chloramphenicol acetyltransferase protein. Transactivation of the calreticulin promoter was also increased by fourfold in NIH/3T3 cells treated with bradykinin, a hormone that induces Ca2+ release from the intracellular Ca2+ stores. Analysis of the promoter deletion constructs revealed that A23187- and thapsigargin-responsive regions are confined to two regions (−115 to −260 and −685 to −1,763) in the calreticulin promoter that contain the CCAAT nucleotide sequences. Northern blot analysis of cells treated with A23187, or with thapsigargin, revealed a fivefold increase in calreticulin mRNA levels. Thapsigargin also induced a fourfold increase in calreticulun protein levels. Importantly, we show by nuclear run-on transcription analysis that calreticulin gene transcription is increased in NIH/3T3 cells treated with A23187 and thapsigargin in vivo. This increase in gene expression required over 4 h of continuous incubation with the drugs and was also sensitive to treatment with cycloheximide, suggesting that it is dependent on protein synthesis. Changes in the concentration of extracellular and cytoplasmic Ca2+ did not affect the increased expression of the calreticulin gene. These studies suggest that stress response to the depletion of intracellular Ca2+ stores induces expression of the calreticulin gene in vitro

  12. The frustrated gene: origins of eukaryotic gene expression

    PubMed Central

    Madhani, Hiten D.

    2014-01-01

    Eukarytotic gene expression is frustrated by a series of steps that are generally not observed in prokaryotes and are therefore not essential for the basic chemistry of transcription and translation. Their evolution may have been driven by the need to defend against parasitic nucleic acids. PMID:24209615

  13. Trigger finger, tendinosis, and intratendinous gene expression.

    PubMed

    Lundin, A-C; Aspenberg, P; Eliasson, P

    2014-04-01

    The pathogenesis of trigger finger has generally been ascribed to primary changes in the first annular ligament. In contrast, we recently found histological changes in the tendons, similar to the findings in Achilles tendinosis or tendinopathy. We therefore hypothesized that trigger finger tendons would show differences in gene expression in comparison to normal tendons in a pattern similar to what is published for Achilles tendinosis. We performed quantitative real-time polymerase chain reaction on biopsies from finger flexor tendons, 13 trigger fingers and 13 apparently healthy control tendons, to assess the expression of 10 genes which have been described to be differently expressed in tendinosis (collagen type 1a1, collagen 3a1, MMP-2, MMP-3, ADAMTS-5, TIMP-3, aggrecan, biglycan, decorin, and versican). In trigger finger tendons, collagen types 1a1 and 3a1, aggrecan and biglycan were all up-regulated, and MMP-3and TIMP-3 were down-regulated. These changes were statistically significant and have been previously described for Achilles tendinosis. The remaining four genes were not significantly altered. The changes in gene expression support the hypothesis that trigger finger is a form of tendinosis. Because trigger finger is a common condition, often treated surgically, it could provide opportunities for clinical research on tendinosis.

  14. The low noise limit in gene expression

    SciTech Connect

    Dar, Roy D.; Weinberger, Leor S.; Cox, Chris D.; Simpson, Michael L.; Razooky, Brandon S.

    2015-10-21

    Protein noise measurements are increasingly used to elucidate biophysical parameters. Unfortunately noise analyses are often at odds with directly measured parameters. Here we show that these inconsistencies arise from two problematic analytical choices: (i) the assumption that protein translation rate is invariant for different proteins of different abundances, which has inadvertently led to (ii) the assumption that a large constitutive extrinsic noise sets the low noise limit in gene expression. While growing evidence suggests that transcriptional bursting may set the low noise limit, variability in translational bursting has been largely ignored. We show that genome-wide systematic variation in translational efficiency can-and in the case of E. coli does-control the low noise limit in gene expression. Therefore constitutive extrinsic noise is small and only plays a role in the absence of a systematic variation in translational efficiency. Lastly, these results show the existence of two distinct expression noise patterns: (1) a global noise floor uniformly imposed on all genes by expression bursting; and (2) high noise distributed to only a select group of genes.

  15. The Low Noise Limit in Gene Expression

    PubMed Central

    Dar, Roy D.; Razooky, Brandon S.; Weinberger, Leor S.; Cox, Chris D.; Simpson, Michael L.

    2015-01-01

    Protein noise measurements are increasingly used to elucidate biophysical parameters. Unfortunately noise analyses are often at odds with directly measured parameters. Here we show that these inconsistencies arise from two problematic analytical choices: (i) the assumption that protein translation rate is invariant for different proteins of different abundances, which has inadvertently led to (ii) the assumption that a large constitutive extrinsic noise sets the low noise limit in gene expression. While growing evidence suggests that transcriptional bursting may set the low noise limit, variability in translational bursting has been largely ignored. We show that genome-wide systematic variation in translational efficiency can–and in the case of E. coli does–control the low noise limit in gene expression. Therefore constitutive extrinsic noise is small and only plays a role in the absence of a systematic variation in translational efficiency. These results show the existence of two distinct expression noise patterns: (1) a global noise floor uniformly imposed on all genes by expression bursting; and (2) high noise distributed to only a select group of genes. PMID:26488303

  16. Digital gene expression signatures for maize development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genome-wide expression signatures detect specific perturbations in developmental programs and contribute to functional resolution of key regulatory networks. In maize (Zea mays) inflorescences, mutations in the RAMOSA (RA) genes affect determinacy of axillary meristems and thus alter branching patt...

  17. Analysis of baseline gene expression levels from ...

    EPA Pesticide Factsheets

    The use of gene expression profiling to predict chemical mode of action would be enhanced by better characterization of variance due to individual, environmental, and technical factors. Meta-analysis of microarray data from untreated or vehicle-treated animals within the control arm of toxicogenomics studies has yielded useful information on baseline fluctuations in gene expression. A dataset of control animal microarray expression data was assembled by a working group of the Health and Environmental Sciences Institute's Technical Committee on the Application of Genomics in Mechanism Based Risk Assessment in order to provide a public resource for assessments of variability in baseline gene expression. Data from over 500 Affymetrix microarrays from control rat liver and kidney were collected from 16 different institutions. Thirty-five biological and technical factors were obtained for each animal, describing a wide range of study characteristics, and a subset were evaluated in detail for their contribution to total variability using multivariate statistical and graphical techniques. The study factors that emerged as key sources of variability included gender, organ section, strain, and fasting state. These and other study factors were identified as key descriptors that should be included in the minimal information about a toxicogenomics study needed for interpretation of results by an independent source. Genes that are the most and least variable, gender-selectiv

  18. Multiple Stochastic Point Processes in Gene Expression

    NASA Astrophysics Data System (ADS)

    Murugan, Rajamanickam

    2008-04-01

    We generalize the idea of multiple-stochasticity in chemical reaction systems to gene expression. Using Chemical Langevin Equation approach we investigate how this multiple-stochasticity can influence the overall molecular number fluctuations. We show that the main sources of this multiple-stochasticity in gene expression could be the randomness in transcription and translation initiation times which in turn originates from the underlying bio-macromolecular recognition processes such as the site-specific DNA-protein interactions and therefore can be internally regulated by the supra-molecular structural factors such as the condensation/super-coiling of DNA. Our theory predicts that (1) in case of gene expression system, the variances ( φ) introduced by the randomness in transcription and translation initiation-times approximately scales with the degree of condensation ( s) of DNA or mRNA as φ ∝ s -6. From the theoretical analysis of the Fano factor as well as coefficient of variation associated with the protein number fluctuations we predict that (2) unlike the singly-stochastic case where the Fano factor has been shown to be a monotonous function of translation rate, in case of multiple-stochastic gene expression the Fano factor is a turn over function with a definite minimum. This in turn suggests that the multiple-stochastic processes can also be well tuned to behave like a singly-stochastic point processes by adjusting the rate parameters.

  19. The low noise limit in gene expression

    DOE PAGES

    Dar, Roy D.; Weinberger, Leor S.; Cox, Chris D.; ...

    2015-10-21

    Protein noise measurements are increasingly used to elucidate biophysical parameters. Unfortunately noise analyses are often at odds with directly measured parameters. Here we show that these inconsistencies arise from two problematic analytical choices: (i) the assumption that protein translation rate is invariant for different proteins of different abundances, which has inadvertently led to (ii) the assumption that a large constitutive extrinsic noise sets the low noise limit in gene expression. While growing evidence suggests that transcriptional bursting may set the low noise limit, variability in translational bursting has been largely ignored. We show that genome-wide systematic variation in translational efficiencymore » can-and in the case of E. coli does-control the low noise limit in gene expression. Therefore constitutive extrinsic noise is small and only plays a role in the absence of a systematic variation in translational efficiency. Lastly, these results show the existence of two distinct expression noise patterns: (1) a global noise floor uniformly imposed on all genes by expression bursting; and (2) high noise distributed to only a select group of genes.« less

  20. Expression of mouse metallothionein genes in tobacco

    SciTech Connect

    Maiti, I.B.; Yeargan, R.; Wagner, G.J.; Hunt, A.G. )

    1990-05-01

    We have expressed a mouse metallothionein (NT) gene in tobacco under control of the cauliflower mosaic virus (CaMV) 35S promoter and a pea ribulose-1,5-bisphosphate carboxylase small subunit (rbcS) gene promoter. Seedlings in which MT gene expression is driven by the 35S promoter are resistant to toxic levels of cadmium. Mature plants carrying the 35S-MT gene accumulate less Cd in their leaves when exposed to low levels of Cd in laboratory growth conditions. Plants with the rbcS-MT construction express this gene in a light-regulated and tissue-specific manner, as expected. Moreover, the MT levels in leaves in these plants are about 20% of those seen in 35S-MT plants. These plants are currently being tested for Cd resistance. In addition, a small field evaluation of 35S-MT lines for Cd levels is being evaluated. These experiments will address the possibility of using MTs to alter Cd levels in crop species.

  1. Regulation of methane genes and genome expression

    SciTech Connect

    John N. Reeve

    2009-09-09

    At the start of this project, it was known that methanogens were Archaeabacteria (now Archaea) and were therefore predicted to have gene expression and regulatory systems different from Bacteria, but few of the molecular biology details were established. The goals were then to establish the structures and organizations of genes in methanogens, and to develop the genetic technologies needed to investigate and dissect methanogen gene expression and regulation in vivo. By cloning and sequencing, we established the gene and operon structures of all of the “methane” genes that encode the enzymes that catalyze methane biosynthesis from carbon dioxide and hydrogen. This work identified unique sequences in the methane gene that we designated mcrA, that encodes the largest subunit of methyl-coenzyme M reductase, that could be used to identify methanogen DNA and establish methanogen phylogenetic relationships. McrA sequences are now the accepted standard and used extensively as hybridization probes to identify and quantify methanogens in environmental research. With the methane genes in hand, we used northern blot and then later whole-genome microarray hybridization analyses to establish how growth phase and substrate availability regulated methane gene expression in Methanobacterium thermautotrophicus ΔH (now Methanothermobacter thermautotrophicus). Isoenzymes or pairs of functionally equivalent enzymes catalyze several steps in the hydrogen-dependent reduction of carbon dioxide to methane. We established that hydrogen availability determine which of these pairs of methane genes is expressed and therefore which of the alternative enzymes is employed to catalyze methane biosynthesis under different environmental conditions. As were unable to establish a reliable genetic system for M. thermautotrophicus, we developed in vitro transcription as an alternative system to investigate methanogen gene expression and regulation. This led to the discovery that an archaeal protein

  2. Fluid Mechanics, Arterial Disease, and Gene Expression

    PubMed Central

    Tarbell, John M.; Shi, Zhong-Dong; Dunn, Jessilyn; Jo, Hanjoong

    2014-01-01

    This review places modern research developments in vascular mechanobiology in the context of hemodynamic phenomena in the cardiovascular system and the discrete localization of vascular disease. The modern origins of this field are traced, beginning in the 1960s when associations between flow characteristics, particularly blood flow–induced wall shear stress, and the localization of atherosclerotic plaques were uncovered, and continuing to fluid shear stress effects on the vascular lining endothelial) cells (ECs), including their effects on EC morphology, biochemical production, and gene expression. The earliest single-gene studies and genome-wide analyses are considered. The final section moves from the ECs lining the vessel wall to the smooth muscle cells and fibroblasts within the wall that are fluid me chanically activated by interstitial flow that imposes shear stresses on their surfaces comparable with those of flowing blood on EC surfaces. Interstitial flow stimulates biochemical production and gene expression, much like blood flow on ECs. PMID:25360054

  3. Fluid Mechanics, Arterial Disease, and Gene Expression.

    PubMed

    Tarbell, John M; Shi, Zhong-Dong; Dunn, Jessilyn; Jo, Hanjoong

    2014-01-01

    This review places modern research developments in vascular mechanobiology in the context of hemodynamic phenomena in the cardiovascular system and the discrete localization of vascular disease. The modern origins of this field are traced, beginning in the 1960s when associations between flow characteristics, particularly blood flow-induced wall shear stress, and the localization of atherosclerotic plaques were uncovered, and continuing to fluid shear stress effects on the vascular lining endothelial) cells (ECs), including their effects on EC morphology, biochemical production, and gene expression. The earliest single-gene studies and genome-wide analyses are considered. The final section moves from the ECs lining the vessel wall to the smooth muscle cells and fibroblasts within the wall that are fluid me chanically activated by interstitial flow that imposes shear stresses on their surfaces comparable with those of flowing blood on EC surfaces. Interstitial flow stimulates biochemical production and gene expression, much like blood flow on ECs.

  4. Gene expression profiling of human ovarian tumours

    PubMed Central

    Biade, S; Marinucci, M; Schick, J; Roberts, D; Workman, G; Sage, E H; O'Dwyer, P J; LiVolsi, V A; Johnson, S W

    2006-01-01

    There is currently a lack of reliable diagnostic and prognostic markers for ovarian cancer. We established gene expression profiles for 120 human ovarian tumours to identify determinants of histologic subtype, grade and degree of malignancy. Unsupervised cluster analysis of the most variable set of expression data resulted in three major tumour groups. One consisted predominantly of benign tumours, one contained mostly malignant tumours, and one was comprised of a mixture of borderline and malignant tumours. Using two supervised approaches, we identified a set of genes that distinguished the benign, borderline and malignant phenotypes. These algorithms were unable to establish profiles for histologic subtype or grade. To validate these findings, the expression of 21 candidate genes selected from these analyses was measured by quantitative RT–PCR using an independent set of tumour samples. Hierarchical clustering of these data resulted in two major groups, one benign and one malignant, with the borderline tumours interspersed between the two groups. These results indicate that borderline ovarian tumours may be classified as either benign or malignant, and that this classifier could be useful for predicting the clinical course of borderline tumours. Immunohistochemical analysis also demonstrated increased expression of CD24 antigen in malignant versus benign tumour tissue. The data that we have generated will contribute to a growing body of expression data that more accurately define the biologic and clinical characteristics of ovarian cancers. PMID:16969345

  5. Gene expression profiling of human ovarian tumours.

    PubMed

    Biade, S; Marinucci, M; Schick, J; Roberts, D; Workman, G; Sage, E H; O'Dwyer, P J; Livolsi, V A; Johnson, S W

    2006-10-23

    There is currently a lack of reliable diagnostic and prognostic markers for ovarian cancer. We established gene expression profiles for 120 human ovarian tumours to identify determinants of histologic subtype, grade and degree of malignancy. Unsupervised cluster analysis of the most variable set of expression data resulted in three major tumour groups. One consisted predominantly of benign tumours, one contained mostly malignant tumours, and one was comprised of a mixture of borderline and malignant tumours. Using two supervised approaches, we identified a set of genes that distinguished the benign, borderline and malignant phenotypes. These algorithms were unable to establish profiles for histologic subtype or grade. To validate these findings, the expression of 21 candidate genes selected from these analyses was measured by quantitative RT-PCR using an independent set of tumour samples. Hierarchical clustering of these data resulted in two major groups, one benign and one malignant, with the borderline tumours interspersed between the two groups. These results indicate that borderline ovarian tumours may be classified as either benign or malignant, and that this classifier could be useful for predicting the clinical course of borderline tumours. Immunohistochemical analysis also demonstrated increased expression of CD24 antigen in malignant versus benign tumour tissue. The data that we have generated will contribute to a growing body of expression data that more accurately define the biologic and clinical characteristics of ovarian cancers.

  6. Repression of gene expression by oxidative stress.

    PubMed Central

    Morel, Y; Barouki, R

    1999-01-01

    Gene expression is modulated by both physiological signals (hormones, cytokines, etc.) and environmental stimuli (physical parameters, xenobiotics, etc.). Oxidative stress appears to be a key pleiotropic modulator which may be involved in either pathway. Indeed, reactive oxygen species (ROS) have been described as second messengers for several growth factors and cytokines, but have also been shown to rise following cellular insults such as xenobiotic metabolism or enzymic deficiency. Extensive studies on the induction of stress-response genes by oxidative stress have been reported. In contrast, owing to the historical focus on gene induction, less attention has been paid to gene repression by ROS. However, a growing number of studies have shown that moderate (i.e. non-cytotoxic) oxidative stress specifically down-regulates the expression of various genes. In this review, we describe the alteration of several physiological functions resulting from oxidative-stress-mediated inhibition of gene transcription. We will then focus on the repressive oxidative modulation of various transcription factors elicited by ROS. PMID:10477257

  7. [Structure and expression of thyroglobulin gene].

    PubMed

    Vassart, G; Brocas, H; Christophe, D; de Martynoff, G; Leriche, A; Mercken, L; Pohl, V; Van Heuverswyn, B

    1982-01-01

    Thyroglobulin is composed of two 300000 dalton polypeptide chains, translated from an 8000 base mRNA. Preparation of a full length cDNA and its cloning in E. coli have lead to the demonstration that the polypeptides of thyroglobulin protomers were identical. Used as molecular probes, the cloned cDNA allowed the isolation of a fragment of thyroglobulin gene. Electron microscopic studies have demonstrated that this gene contains more than 90% intronic material separating small size exons (less than 200 bp). Sequencing of bovine thyroglobulin structural gene is in progress. Preliminary results show evidence for the existence of repetitive segments. Availability of cloned DNA complementary to bovine and human thyroglobulin mRNA allows the study of genetic defects of thyroglobulin gene expression in the human and in various animal models.

  8. Determining Physical Mechanisms of Gene Expression Regulation from Single Cell Gene Expression Data

    PubMed Central

    Moignard, Victoria; Göttgens, Berthold; Adryan, Boris

    2016-01-01

    Many genes are expressed in bursts, which can contribute to cell-to-cell heterogeneity. It is now possible to measure this heterogeneity with high throughput single cell gene expression assays (single cell qPCR and RNA-seq). These experimental approaches generate gene expression distributions which can be used to estimate the kinetic parameters of gene expression bursting, namely the rate that genes turn on, the rate that genes turn off, and the rate of transcription. We construct a complete pipeline for the analysis of single cell qPCR data that uses the mathematics behind bursty expression to develop more accurate and robust algorithms for analyzing the origin of heterogeneity in experimental samples, specifically an algorithm for clustering cells by their bursting behavior (Simulated Annealing for Bursty Expression Clustering, SABEC) and a statistical tool for comparing the kinetic parameters of bursty expression across populations of cells (Estimation of Parameter changes in Kinetics, EPiK). We applied these methods to hematopoiesis, including a new single cell dataset in which transcription factors (TFs) involved in the earliest branchpoint of blood differentiation were individually up- and down-regulated. We could identify two unique sub-populations within a seemingly homogenous group of hematopoietic stem cells. In addition, we could predict regulatory mechanisms controlling the expression levels of eighteen key hematopoietic transcription factors throughout differentiation. Detailed information about gene regulatory mechanisms can therefore be obtained simply from high throughput single cell gene expression data, which should be widely applicable given the rapid expansion of single cell genomics. PMID:27551778

  9. Coevolution of gene expression among interacting proteins

    SciTech Connect

    Fraser, Hunter B.; Hirsh, Aaron E.; Wall, Dennis P.; Eisen,Michael B.

    2004-03-01

    Physically interacting proteins or parts of proteins are expected to evolve in a coordinated manner that preserves proper interactions. Such coevolution at the amino acid-sequence level is well documented and has been used to predict interacting proteins, domains, and amino acids. Interacting proteins are also often precisely coexpressed with one another, presumably to maintain proper stoichiometry among interacting components. Here, we show that the expression levels of physically interacting proteins coevolve. We estimate average expression levels of genes from four closely related fungi of the genus Saccharomyces using the codon adaptation index and show that expression levels of interacting proteins exhibit coordinated changes in these different species. We find that this coevolution of expression is a more powerful predictor of physical interaction than is coevolution of amino acid sequence. These results demonstrate previously uncharacterized coevolution of gene expression, adding a different dimension to the study of the coevolution of interacting proteins and underscoring the importance of maintaining coexpression of interacting proteins over evolutionary time. Our results also suggest that expression coevolution can be used for computational prediction of protein protein interactions.

  10. Differential var gene expression in children with malaria and antidromic effects on host gene expression.

    PubMed

    Kalmbach, Yvonne; Rottmann, Matthias; Kombila, Maryvonne; Kremsner, Peter G; Beck, Hans-Peter; Kun, Jürgen F J

    2010-07-15

    Among 62 children with mild malaria, cerebral malaria, or severe malarial anemia, we analyzed the transcription of different var gene types. There was no difference in parasitemia level or body temperature between groups. However, a significantly different expression pattern was observed in children with cerebral malaria, compared with that in patients in the other 2 groups: children with cerebral malaria had lower expression of the upsA subtype but higher expression of the upsB and upsC subtypes. Furthermore, expression of human genes responsive to tumor necrosis factor and hypoxia correlated with distinct ups types.

  11. Transcriptome-Level Signatures in Gene Expression and Gene Expression Variability during Bacterial Adaptive Evolution

    PubMed Central

    Erickson, Keesha E.; Otoupal, Peter B.

    2017-01-01

    ABSTRACT Antibiotic-resistant bacteria are an increasingly serious public health concern, as strains emerge that demonstrate resistance to almost all available treatments. One factor that contributes to the crisis is the adaptive ability of bacteria, which exhibit remarkable phenotypic and gene expression heterogeneity in order to gain a survival advantage in damaging environments. This high degree of variability in gene expression across biological populations makes it a challenging task to identify key regulators of bacterial adaptation. Here, we research the regulation of adaptive resistance by investigating transcriptome profiles of Escherichia coli upon adaptation to disparate toxins, including antibiotics and biofuels. We locate potential target genes via conventional gene expression analysis as well as using a new analysis technique examining differential gene expression variability. By investigating trends across the diverse adaptation conditions, we identify a focused set of genes with conserved behavior, including those involved in cell motility, metabolism, membrane structure, and transport, and several genes of unknown function. To validate the biological relevance of the observed changes, we synthetically perturb gene expression using clustered regularly interspaced short palindromic repeat (CRISPR)-dCas9. Manipulation of select genes in combination with antibiotic treatment promotes adaptive resistance as demonstrated by an increased degree of antibiotic tolerance and heterogeneity in MICs. We study the mechanisms by which identified genes influence adaptation and find that select differentially variable genes have the potential to impact metabolic rates, mutation rates, and motility. Overall, this work provides evidence for a complex nongenetic response, encompassing shifts in gene expression and gene expression variability, which underlies adaptive resistance. IMPORTANCE Even initially sensitive bacteria can rapidly thwart antibiotic treatment

  12. Transcriptome-Level Signatures in Gene Expression and Gene Expression Variability during Bacterial Adaptive Evolution.

    PubMed

    Erickson, Keesha E; Otoupal, Peter B; Chatterjee, Anushree

    2017-01-01

    Antibiotic-resistant bacteria are an increasingly serious public health concern, as strains emerge that demonstrate resistance to almost all available treatments. One factor that contributes to the crisis is the adaptive ability of bacteria, which exhibit remarkable phenotypic and gene expression heterogeneity in order to gain a survival advantage in damaging environments. This high degree of variability in gene expression across biological populations makes it a challenging task to identify key regulators of bacterial adaptation. Here, we research the regulation of adaptive resistance by investigating transcriptome profiles of Escherichia coli upon adaptation to disparate toxins, including antibiotics and biofuels. We locate potential target genes via conventional gene expression analysis as well as using a new analysis technique examining differential gene expression variability. By investigating trends across the diverse adaptation conditions, we identify a focused set of genes with conserved behavior, including those involved in cell motility, metabolism, membrane structure, and transport, and several genes of unknown function. To validate the biological relevance of the observed changes, we synthetically perturb gene expression using clustered regularly interspaced short palindromic repeat (CRISPR)-dCas9. Manipulation of select genes in combination with antibiotic treatment promotes adaptive resistance as demonstrated by an increased degree of antibiotic tolerance and heterogeneity in MICs. We study the mechanisms by which identified genes influence adaptation and find that select differentially variable genes have the potential to impact metabolic rates, mutation rates, and motility. Overall, this work provides evidence for a complex nongenetic response, encompassing shifts in gene expression and gene expression variability, which underlies adaptive resistance. IMPORTANCE Even initially sensitive bacteria can rapidly thwart antibiotic treatment through stress

  13. Gene expression regulation in roots under drought.

    PubMed

    Janiak, Agnieszka; Kwaśniewski, Mirosław; Szarejko, Iwona

    2016-02-01

    Stress signalling and regulatory networks controlling expression of target genes are the basis of plant response to drought. Roots are the first organs exposed to water deficiency in the soil and are the place of drought sensing. Signalling cascades transfer chemical signals toward the shoot and initiate molecular responses that lead to the biochemical and morphological changes that allow plants to be protected against water loss and to tolerate stress conditions. Here, we present an overview of signalling network and gene expression regulation pathways that are actively induced in roots under drought stress. In particular, the role of several transcription factor (TF) families, including DREB, AP2/ERF, NAC, bZIP, MYC, CAMTA, Alfin-like and Q-type ZFP, in the regulation of root response to drought are highlighted. The information provided includes available data on mutual interactions between these TFs together with their regulation by plant hormones and other signalling molecules. The most significant downstream target genes and molecular processes that are controlled by the regulatory factors are given. These data are also coupled with information about the influence of the described regulatory networks on root traits and root development which may translate to enhanced drought tolerance. This is the first literature survey demonstrating the gene expression regulatory machinery that is induced by drought stress, presented from the perspective of roots.

  14. Expression of bacterial genes in plant cells.

    PubMed Central

    Fraley, R T; Rogers, S G; Horsch, R B; Sanders, P R; Flick, J S; Adams, S P; Bittner, M L; Brand, L A; Fink, C L; Fry, J S; Galluppi, G R; Goldberg, S B; Hoffmann, N L; Woo, S C

    1983-01-01

    Chimeric bacterial genes conferring resistance to aminoglycoside antibiotics have been inserted into the Agrobacterium tumefaciens tumor-inducing (Ti) plasmid and introduced into plant cells by in vitro transformation techniques. The chimeric genes contain the nopaline synthase 5' and 3' regulatory regions joined to the genes for neomycin phosphotransferase type I or type II. The chimeric genes were cloned into an intermediate vector, pMON120, and inserted into pTiB6S3 by recombination and then introduced into petunia and tobacco cells by cocultivating A. tumefaciens cells with protoplast-derived cells. Southern hybridization was used to confirm the presence of the chimeric genes in the transformed plant tissues. Expression of the chimeric genes was determined by the ability of the transformed cells to proliferate on medium containing normally inhibitory levels of kanamycin (50 micrograms/ml) or other aminoglycoside antibiotics. Plant cells transformed by wild-type pTiB6S3 or derivatives carrying the bacterial neomycin phosphotransferase genes with their own promoters failed to grow under these conditions. The significance of these results for plant genetic engineering is discussed. Images PMID:6308651

  15. Transient gene expression in electroporated Solanum protoplasts.

    PubMed

    Jones, H; Ooms, G; Jones, M G

    1989-11-01

    Electroporation was used to evaluate parameters important in transient gene expression in potato protoplasts. The protoplasts were from leaves of wild potato Solanum brevidens, and from leaves, tubers and suspension cells of cultivated Solanum tuberosum cv. Désirée. Reporter enzyme activity, chloramphenicol acetyl transferase (CAT) under the control of the cauliflower mosaic virus (CaMV) 35S promoter, depended on the field strength and the pulse duration used for electroporation. Using field pulses of 85 ms duration, the optimum field strengths for maximum CAT activity were: S. brevidens mesophyll protoplasts--250 V/cm; Désirée mesophyll protoplasts--225 V/cm; Désirée suspension culture protoplasts--225 V/cm; and Désirée tuber protoplasts--150 V/cm. The optimum field strengths correlated inversely with the size of the protoplasts electroporated; this is consistent with biophysical theory. In time courses, maximum CAT activity (in Désirée mesophyll protoplasts) occurred 36-48 h after electroporation. Examination at optimised conditions of a chimaeric gene consisting of a class II patatin promoter linked to the beta-glucuronidase (gus) gene, showed expression (at DNA concentrations between 0-10 pmol/ml) comparable to the CaMV 35S promoter in both tuber and mesophyll protoplasts. At higher DNA concentrations (20-30 pmol/ml) the patatin promoter directed 4-5 times higher levels of gus expression. Implications and potential contributions towards studying gene expression, in particular of homologous genes in potato, are discussed.

  16. Characterization of the Ala62Pro polymorphic variant of human cytochrome P450 1A1 using recombinant protein expression

    SciTech Connect

    Lee, Seung Heon; Kang, Sukmo; Dong, Mi Sook; Park, Jung-Duck; Park, Jinseo; Rhee, Sangkee; Ryu, Doug-Young

    2015-06-15

    Cytochrome P450 (CYP) 1A1 is a heme-containing enzyme involved in detoxification of hydrophobic pollutants. Its Ala62Pro variant has been identified previously. Ala62 is located in α-helix A of CYP1A1. Residues such as Pro and Gly are α-helix breakers. In this study, the Ala62Pro variant was characterized using heterologous expression. E. coli expressing the Ala62Pro variant, and the purified variant protein, had lower CYP (i.e. holoenzyme) contents than their wild-type (WT) equivalents. The CYP variant from E. coli and mammalian cells exhibited lower 7-ethoxyresorufin O-dealkylation (EROD) and benzo[a]pyrene hydroxylation activities than the WT. Enhanced supplementation of a heme precursor during E. coli culture did not increase CYP content in E. coli expressing the variant, but did for the WT. As for Ala62Pro, E. coli expressing an Ala62Gly variant had a lower CYP content than the WT counterpart, but substitution of Ala62 with α-helix-compatible residues such as Ser and Val partially recovered the level of CYP produced. Microsomes from mammalian cells expressing Ala62Pro and Ala62Gly variants exhibited lower EROD activities than those expressing the WT or Ala62Val variant. A region harboring α-helix A has interactions with another region containing heme-interacting residues. Site-directed mutagenesis analyses suggest the importance of interactions between the two regions on holoenzyme expression. Together, these findings suggest that the Ala62Pro substitution leads to changes in protein characteristics and function of CYP1A1 via structural disturbance of the region where the residue is located. - Highlights: • Ala62 is located in α-helix A of the carcinogen-metabolizing enzyme CYP1A1. • Pro acts as an α-helix breaker. • A variant protein of CYP1A1, Ala62Pro, had lower heme content than the wild-type. • The variant of CYP1A1 had lower enzyme activities than the wild-type.

  17. Toward stable gene expression in CHO cells

    PubMed Central

    Mariati; Koh, Esther YC; Yeo, Jessna HM; Ho, Steven CL; Yang, Yuansheng

    2014-01-01

    Maintaining high gene expression level during long-term culture is critical when producing therapeutic recombinant proteins using mammalian cells. Transcriptional silencing of promoters, most likely due to epigenetic events such as DNA methylation and histone modifications, is one of the major mechanisms causing production instability. Previous studies demonstrated that the core CpG island element (IE) from the hamster adenine phosphoribosyltransferase gene is effective to prevent DNA methylation. We generated one set of modified human cytomegalovirus (hCMV) promoters by insertion of one or two copies of IE in either forward or reverse orientations into different locations of the hCMV promoter. The modified hCMV with one copy of IE inserted between the hCMV enhancer and core promoter in reverse orientation (MR1) was most effective at enhancing expression stability in CHO cells without comprising expression level when compared with the wild type hCMV. We also found that insertion of IE into a chimeric murine CMV (mCMV) enhancer and human elongation factor-1α core (hEF) promoter in reverse orientation did not enhance expression stability, indicating that the effect of IE on expression stability is possibly promoter specific. PMID:25482237

  18. Engineering Genes for Predictable Protein Expression

    PubMed Central

    Gustafsson, Claes; Minshull, Jeremy; Govindarajan, Sridhar; Ness, Jon; Villalobos, Alan; Welch, Mark

    2013-01-01

    The DNA sequence used to encode a polypeptide can have dramatic effects on its expression. Lack of readily available tools has until recently inhibited meaningful experimental investigation of this phenomenon. Advances in synthetic biology and the application of modern engineering approaches now provide the tools for systematic analysis of the sequence variables affecting heterologous expression of recombinant proteins. We here discuss how these new tools are being applied and how they circumvent the constraints of previous approaches, highlighting some of the surprising and promising results emerging from the developing field of gene engineering. PMID:22425659

  19. Engineering genes for predictable protein expression.

    PubMed

    Gustafsson, Claes; Minshull, Jeremy; Govindarajan, Sridhar; Ness, Jon; Villalobos, Alan; Welch, Mark

    2012-05-01

    The DNA sequence used to encode a polypeptide can have dramatic effects on its expression. Lack of readily available tools has until recently inhibited meaningful experimental investigation of this phenomenon. Advances in synthetic biology and the application of modern engineering approaches now provide the tools for systematic analysis of the sequence variables affecting heterologous expression of recombinant proteins. We here discuss how these new tools are being applied and how they circumvent the constraints of previous approaches, highlighting some of the surprising and promising results emerging from the developing field of gene engineering.

  20. Cancer outlier differential gene expression detection.

    PubMed

    Wu, Baolin

    2007-07-01

    We study statistical methods to detect cancer genes that are over- or down-expressed in some but not all samples in a disease group. This has proven useful in cancer studies where oncogenes are activated only in a small subset of samples. We propose the outlier robust t-statistic (ORT), which is intuitively motivated from the t-statistic, the most commonly used differential gene expression detection method. Using real and simulation studies, we compare the ORT to the recently proposed cancer outlier profile analysis (Tomlins and others, 2005) and the outlier sum statistic of Tibshirani and Hastie (2006). The proposed method often has more detection power and smaller false discovery rates. Supplementary information can be found at http://www.biostat.umn.edu/~baolin/research/ort.html.

  1. Programming gene expression with combinatorial promoters

    PubMed Central

    Cox, Robert Sidney; Surette, Michael G; Elowitz, Michael B

    2007-01-01

    Promoters control the expression of genes in response to one or more transcription factors (TFs). The architecture of a promoter is the arrangement and type of binding sites within it. To understand natural genetic circuits and to design promoters for synthetic biology, it is essential to understand the relationship between promoter function and architecture. We constructed a combinatorial library of random promoter architectures. We characterized 288 promoters in Escherichia coli, each containing up to three inputs from four different TFs. The library design allowed for multiple −10 and −35 boxes, and we observed varied promoter strength over five decades. To further analyze the functional repertoire, we defined a representation of promoter function in terms of regulatory range, logic type, and symmetry. Using these results, we identified heuristic rules for programming gene expression with combinatorial promoters. PMID:18004278

  2. Combinatorial engineering for heterologous gene expression.

    PubMed

    Zwick, Friederike; Lale, Rahmi; Valla, Svein

    2013-01-01

    Tools for strain engineering with predictable outcome are of crucial importance for the nascent field of synthetic biology. The success of combining different DNA biological parts is often restricted by poorly understood factors deriving from the complexity of the systems. We have previously identified variants for different regulatory elements of the expression cassette XylS/Pm. When such elements are combined they act in a manner consistent with their individual behavior, as long as they affect different functions, such as transcription and translation. Interestingly, sequence context does not seem to influence the final outcome significantly. Expression of reporter gene bla could be increased up to 75 times at the protein level by combining three variants in one cassette. For other tested reporter genes similar results were obtained, except that the stimulatory effect was quantitatively less. Combination of individually characterized DNA parts thus stands as suitable method to achieve a desired phenotype.

  3. Structure, expression and functions of MTA genes.

    PubMed

    Kumar, Rakesh; Wang, Rui-An

    2016-05-15

    Metastatic associated proteins (MTA) are integrators of upstream regulatory signals with the ability to act as master coregulators for modifying gene transcriptional activity. The MTA family includes three genes and multiple alternatively spliced variants. The MTA proteins neither have their own enzymatic activity nor have been shown to directly interact with DNA. However, MTA proteins interact with a variety of chromatin remodeling factors and complexes with enzymatic activities for modulating the plasticity of nucleosomes, leading to the repression or derepression of target genes or other extra-nuclear and nucleosome remodeling and histone deacetylase (NuRD)-complex independent activities. The functions of MTA family members are driven by the steady state levels and subcellular localization of MTA proteins, the dynamic nature of modifying signals and enzymes, the structural features and post-translational modification of protein domains, interactions with binding proteins, and the nature of the engaged and resulting features of nucleosomes in the proximity of target genes. In general, MTA1 and MTA2 are the most upregulated genes in human cancer and correlate well with aggressive phenotypes, therapeutic resistance, poor prognosis and ultimately, unfavorable survival of cancer patients. Here we will discuss the structure, expression and functions of the MTA family of genes in the context of cancer cells.

  4. Identifying driver genes in cancer by triangulating gene expression, gene location, and survival data.

    PubMed

    Rouam, Sigrid; Miller, Lance D; Karuturi, R Krishna Murthy

    2014-01-01

    Driver genes are directly responsible for oncogenesis and identifying them is essential in order to fully understand the mechanisms of cancer. However, it is difficult to delineate them from the larger pool of genes that are deregulated in cancer (ie, passenger genes). In order to address this problem, we developed an approach called TRIAngulating Gene Expression (TRIAGE through clinico-genomic intersects). Here, we present a refinement of this approach incorporating a new scoring methodology to identify putative driver genes that are deregulated in cancer. TRIAGE triangulates - or integrates - three levels of information: gene expression, gene location, and patient survival. First, TRIAGE identifies regions of deregulated expression (ie, expression footprints) by deriving a newly established measure called the Local Singular Value Decomposition (LSVD) score for each locus. Driver genes are then distinguished from passenger genes using dual survival analyses. Incorporating measurements of gene expression and weighting them according to the LSVD weight of each tumor, these analyses are performed using the genes located in significant expression footprints. Here, we first use simulated data to characterize the newly established LSVD score. We then present the results of our application of this refined version of TRIAGE to gene expression data from five cancer types. This refined version of TRIAGE not only allowed us to identify known prominent driver genes, such as MMP1, IL8, and COL1A2, but it also led us to identify several novel ones. These results illustrate that TRIAGE complements existing tools, allows for the identification of genes that drive cancer and could perhaps elucidate potential future targets of novel anticancer therapeutics.

  5. Expression and induction of cytochrome p450 isoenzymes in human skin equivalents.

    PubMed

    Neis, M M; Wendel, A; Wiederholt, T; Marquardt, Y; Joussen, S; Baron, J M; Merk, H F

    2010-01-01

    Organotypic skin models are frequently used for a wide range of applications and latterly also for dermatotoxicological studies. To evaluate their practicability for the investigation of xenobiotic metabolism in human skin we compared three types of organotypic skin models, acquired by purchase from different manufacturers, to a self-constructed in-house model with regard to cytochrome P450 (CYP) isoenzyme expression on mRNA and protein level and the inducibility of these enzymes by aryl hydrocarbon receptor ligands. To induce enzyme activity, models were treated with benzanthracene, liquor carbonis detergens, pix lithanthracis or dimethyl sulfoxide as a solvent control. RNA was isolated by phenol-chloroform extraction and purified. Gene expression patterns were studied by cDNA microarray analysis. Microarray data were confirmed by real-time PCR. For quality control of the models and to detect and localize enzyme expression, immunofluorescence staining was performed with antibodies against CYPs and structure proteins. The immunofluorescence staining demonstrated the regular structure of our models. We could provide evidence for the expression of CYP types 1A1, 1B1, 2E1, 2C and 3A5 in organotypic skin models. The expression of CYP1A1 and CYP1B1 was highly inducible by treatment with liquor carbonis detergens. The proof of the expression and inducibility of CYP enzymes in organotypic skin models suggests that skin equivalents are a valuable tool that can emulate CYP-dependent metabolism of drugs and other xenobiotics in human skin.

  6. Gene expression during normal and malignant differentiation

    SciTech Connect

    Andersson, L.C.; Gahmberg, C.G.; Ekblom, P.

    1985-01-01

    This book contains 18 selections. Some of the titles are: Exploring Carcinogenesis with Retroviral and Cellular Oncogenes; Retroviruses, Oncogenes and Evolution; HTLV and Human Neoplasi; Modes of Activation of cMyc Oncogene in B and T Lymphoid Tumors; The Structure and Function of the Epidermal Growth Factor Receptor: Its Relationship to the Protein Product of the V-ERB-B Oncogene; and Expression of Human Retrovirus Genes in Normal and Neoplastic Epithelial Cells.

  7. Nonreplicating vaccinia vector efficiently expresses recombinant genes.

    PubMed

    Sutter, G; Moss, B

    1992-11-15

    Modified vaccinia Ankara (MVA), a highly attenuated vaccinia virus strain that has been safety tested in humans, was evaluated for use as an expression vector. MVA has multiple genomic deletions and is severely host cell restricted: it grows well in avian cells but is unable to multiply in human and most other mammalian cells tested. Nevertheless, we found that replication of viral DNA appeared normal and that both early and late viral proteins were synthesized in human cells. Proteolytic processing of viral structural proteins was inhibited, however, and only immature virus particles were detected by electron microscopy. We constructed an insertion plasmid with the Escherichia coli lacZ gene under the control of the vaccinia virus late promoter P11, flanked by sequences of MVA DNA, to allow homologous recombination at the site of a naturally occurring 3500-base-pair deletion within the MVA genome. MVA recombinants were isolated and propagated in permissive avian cells and shown to express the enzyme beta-galactosidase upon infection of nonpermissive human cells. The amount of enzyme made was similar to that produced by a recombinant of vaccinia virus strain Western Reserve, which also had the lacZ gene under control of the P11 promoter, but multiplied to high titers. Since recombinant gene expression is unimpaired in nonpermissive human cells, MVA may serve as a highly efficient and exceptionally safe vector.

  8. A gene expression biomarker accurately predicts estrogen ...

    EPA Pesticide Factsheets

    The EPA’s vision for the Endocrine Disruptor Screening Program (EDSP) in the 21st Century (EDSP21) includes utilization of high-throughput screening (HTS) assays coupled with computational modeling to prioritize chemicals with the goal of eventually replacing current Tier 1 screening tests. The ToxCast program currently includes 18 HTS in vitro assays that evaluate the ability of chemicals to modulate estrogen receptor α (ERα), an important endocrine target. We propose microarray-based gene expression profiling as a complementary approach to predict ERα modulation and have developed computational methods to identify ERα modulators in an existing database of whole-genome microarray data. The ERα biomarker consisted of 46 ERα-regulated genes with consistent expression patterns across 7 known ER agonists and 3 known ER antagonists. The biomarker was evaluated as a predictive tool using the fold-change rank-based Running Fisher algorithm by comparison to annotated gene expression data sets from experiments in MCF-7 cells. Using 141 comparisons from chemical- and hormone-treated cells, the biomarker gave a balanced accuracy for prediction of ERα activation or suppression of 94% or 93%, respectively. The biomarker was able to correctly classify 18 out of 21 (86%) OECD ER reference chemicals including “very weak” agonists and replicated predictions based on 18 in vitro ER-associated HTS assays. For 114 chemicals present in both the HTS data and the MCF-7 c

  9. Expression of foreign genes in filamentous cyanobacteria

    SciTech Connect

    Kuritz, T.; Wolk, C.P. )

    1993-06-01

    Several advantages make cyanobacteria attractive hosts for biodegradative genes and possibly for other exogenous genes that have practical uses. The authors have obtained expression in Anabaena sp. strain PCC 7120 and Nostoc ellipsosporum of a dechlorination operon, fcbAB, from Arthrobacter globiformis, and have also developed a simple method for qualitative assessment of dechlorination by microorganisms, such as cyanobacteria, whose metabolism is dependent on the presence of chloride in the medium. Transcription of fcbAB under the control of a variety of promoters was monitored by placing luxAB (encoding luciferase) downstream from fcbAB, and by measuring light emission from luciferase. They believe that the system that they have described has value as a means to screen for factors influencing transcription of foreign genes in cyanobacteria.

  10. GeneTIER: prioritization of candidate disease genes using tissue-specific gene expression profiles

    PubMed Central

    Antanaviciute, Agne; Daly, Catherine; Crinnion, Laura A.; Markham, Alexander F.; Watson, Christopher M.; Bonthron, David T.; Carr, Ian M.

    2015-01-01

    Motivation: In attempts to determine the genetic causes of human disease, researchers are often faced with a large number of candidate genes. Linkage studies can point to a genomic region containing hundreds of genes, while the high-throughput sequencing approach will often identify a great number of non-synonymous genetic variants. Since systematic experimental verification of each such candidate gene is not feasible, a method is needed to decide which genes are worth investigating further. Computational gene prioritization presents itself as a solution to this problem, systematically analyzing and sorting each gene from the most to least likely to be the disease-causing gene, in a fraction of the time it would take a researcher to perform such queries manually. Results: Here, we present Gene TIssue Expression Ranker (GeneTIER), a new web-based application for candidate gene prioritization. GeneTIER replaces knowledge-based inference traditionally used in candidate disease gene prioritization applications with experimental data from tissue-specific gene expression datasets and thus largely overcomes the bias toward the better characterized genes/diseases that commonly afflict other methods. We show that our approach is capable of accurate candidate gene prioritization and illustrate its strengths and weaknesses using case study examples. Availability and Implementation: Freely available on the web at http://dna.leeds.ac.uk/GeneTIER/. Contact: umaan@leeds.ac.uk Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25861967

  11. Reduced expression of Autographa californica nucleopolyhedrovirus ORF34, an essential gene, enhances heterologous gene expression

    SciTech Connect

    Salem, Tamer Z.; Zhang, Fengrui; Thiem, Suzanne M.

    2013-01-20

    Autographa californica multiple nucleopolyhedrovirus ORF34 is part of a transcriptional unit that includes ORF32, encoding a viral fibroblast growth factor (FGF) and ORF33. We identified ORF34 as a candidate for deletion to improve protein expression in the baculovirus expression system based on enhanced reporter gene expression in an RNAi screen of virus genes. However, ORF34 was shown to be an essential gene. To explore ORF34 function, deletion (KO34) and rescue bacmids were constructed and characterized. Infection did not spread from primary KO34 transfected cells and supernatants from KO34 transfected cells could not infect fresh Sf21 cells whereas the supernatant from the rescue bacmids transfection could recover the infection. In addition, budded viruses were not observed in KO34 transfected cells by electron microscopy, nor were viral proteins detected from the transfection supernatants by western blots. These demonstrate that ORF34 is an essential gene with a possible role in infectious virus production.

  12. Screening of differentially expressed genes in pathological scar tissues using expression microarray.

    PubMed

    Huang, L P; Mao, Z; Zhang, L; Liu, X X; Huang, C; Jia, Z S

    2015-09-09

    Pathological scar tissues and normal skin tissues were differentiated by screening for differentially expressed genes in pathologic scar tissues via gene expression microarray. The differentially expressed gene data was analyzed by gene ontology and pathway analyses. There were 5001 up- or down-regulated genes in 2-fold differentially expressed genes, 956 up- or down-regulated genes in 5-fold differentially expressed genes, and 114 up- or down-regulated genes in 20-fold differentially expressed genes. Therefore, significant differences were observed in the gene expression in pathological scar tissues and normal foreskin tissues. The development of pathological scar tissues has been correlated to changes in multiple genes and pathways, which are believed to form a dynamic network connection.

  13. Gene expression and IG-DMR hypomethylation of maternally expressed gene 3 in developing corticospinal neurons.

    PubMed

    Qu, Chunsheng; Jiang, Tian; Li, Yong; Wang, Xiongwei; Cao, Huateng; Xu, Hongping; Qu, Jia; Chen, Jie-Guang

    2013-01-01

    The mammalian cerebral cortex plays a central role in higher cognitive functions and in the complex task of motor control. Maternally expressed gene 3 (Meg3) appears to play a role in cortical development and neurodegeneration, but the expression and regulation of Meg3 in the cortex is not clear. In this study, we examined the expression of transcript variants of Meg3 in the developing mouse cerebral cortex. By in situ hybridization, we found that a novel transcript variant of Meg3 with 8 small exons was expressed in the developing cortex, whereas the long isoforms of Meg3 (~11 kb) were enriched in corticospinal neurons (CSNs) in layer V of the cortex. No transcript variants of Meg3 were found in the neural progenitors at E12.5, when the intergenic differential methylation region (IG-DMR) near Meg3 was highly methylated. IG-DMR became demethylated at E15.5 and remained hypomethylated in early CSNs isolated from Fezf2-EGFP transgenic mice. The expression of Meg3 transcript variant 1 was inversely correlated with the IG-DMR methylation level during development. Moreover, expression of paternally expressed gene Peg11 was limited to the upper layers, consistent with the idea that the maternally expressed gene may be preferentially transcribed in the lower layers of the cortex. The spatiotemporal expression pattern of Meg3 suggests that it may participate in the early development of CSNs and contribute to cortical malfunctions related to aberrant imprinting in Meg3.

  14. Gravity-Induced Gene Expression in Plants.

    NASA Astrophysics Data System (ADS)

    Sederoff, Heike; Heber, Steffen; Howard, Brian; Myburg-Nichols, Henrietta; Hammond, Rebecca; Salinas-Mondragon, Raul; Brown, Christopher S.

    Plants sense changes in their orientation towards the vector of gravity and respond with directional growth. Several metabolites in the signal transduction cascade have been identified. However, very little is known about the interaction between these sensing and signal transduction events and even less is known about their role in the differential growth response. Gravity induced changes in transcript abundance have been identified in Arabidopsis whole seedlings and root apices (Moseyko et al. 2002; Kimbrough et al. 2004). Gravity induced transcript abundance changes can be observed within less than 1 min after stimulation (Salinas-Mondragon et al. 2005). Gene expression however requires not only transcription but also translation of the mRNA. Translation can only occur when mRNA is associated with ribosomes, even though not all mRNA associated with ribosomes is actively translated. To approximate translational capacity we quantified whole genome transcript abundances in corn stem pulvini during the first hour after gravity stimulation in total and poly-ribosomal fractions. As in Arabidopsis root apices, transcript abundances of several clusters of genes responded to gravity stimulation. The vast majority of these transcripts were also found to associate with polyribosomes in the same temporal and quantitative pattern. These genes are transcriptionally regulated by gravity stimulation, but do not exhibit translational regulation. However, a small group of genes showed increased transcriptional regulation after gravity stimulation, but no association with polysomes. These transcripts likely are translationally repressed. The mechanism of translational repression for these transcripts is unknown. Based on the hypothesis that the genes essential for gravitropic responses should be expressed in most or all species, we compared the temporal gravity induced expression pattern of all orthologs identified between maize and Arabidopsis. A small group of genes showed high

  15. X chromosome regulation of autosomal gene expression in bovine blastocysts.

    PubMed

    Itoh, Yuichiro; Arnold, Arthur P

    2014-10-01

    Although X chromosome inactivation in female mammals evolved to balance the expression of X chromosome and autosomal genes in the two sexes, female embryos pass through developmental stages in which both X chromosomes are active in somatic cells. Bovine blastocysts show higher expression of many X genes in XX than XY embryos, suggesting that X inactivation is not complete. Here, we reanalyzed bovine blastocyst microarray expression data from a network perspective with a focus on interactions between X chromosome and autosomal genes. Whereas male-to-female ratios of expression of autosomal genes were distributed around a mean of 1, X chromosome genes were clearly shifted towards higher expression in females. We generated gene coexpression networks and identified a major module of genes with correlated gene expression that includes female-biased X genes and sexually dimorphic autosomal genes for which the sexual dimorphism is likely driven by the X genes. In this module, expression of X chromosome genes correlates with autosome genes, more than the expression of autosomal genes with each other. Our study identifies correlated patterns of autosomal and X-linked genes that are likely influenced by the sexual imbalance of X gene expression when X inactivation is inefficient.

  16. Regional specificity in deltamethrin induced cytochrome P450 expression in rat brain

    SciTech Connect

    Yadav, Sanjay; Johri, Ashu; Dhawan, Alok; Seth, Prahlad K.; Parmar, Devendra . E-mail: parmar_devendra@hotmail.com

    2006-11-15

    Oral administration of deltamethrin (5 mg/kg x 7 or 15 or 21 days) was found to produce a time-dependent increase in the mRNA expression of xenobiotic metabolizing cytochrome P450 1A1 (CYP1A1), 1A2 and CYP2B1, 2B2 isoenzymes in rat brain. RT-PCR studies further showed that increase in the mRNA expression of these CYP isoenzymes observed after 21 days of exposure was region specific. Hippocampus exhibited maximum increase in the mRNA expression of CYP1A1, which was followed by pons-medulla, cerebellum and hypothalamus. The mRNA expression of CYP2B1 also exhibited maximum increase in the hypothalamus and hippocampus followed by almost similar increase in midbrain and cerebellum. In contrast, mRNA expression of CYP1A2 and CYP2B2, the constitutive isoenzymes exhibited relatively higher increase in pons-medulla, cerebellum and frontal cortex. Immunoblotting studies carried out with polyclonal antibody raised against rat liver CYP1A1/1A2 or CYP2B1/2B2 isoenzymes also showed increase in immunoreactivity comigrating with CYP1A1/1A2 or 2B1/2B2 in the microsomal fractions isolated from hippocampus, hypothalamus and cerebellum of rat treated with deltamethrin. Though the exact relationship of the xenobiotic metabolizing CYPs with the physiological function of the brain is yet to be clearly understood, the increase in the mRNA expression of the CYPs in the brain regions that regulate specific brain functions affected by deltamethrin have further indicated that modulation of these CYPs could be associated with the various endogenous functions of the brain.

  17. Gene expression and cAMP.

    PubMed Central

    Nagamine, Y; Reich, E

    1985-01-01

    By comparing the 5'-flanking region of the porcine gene for the urokinase form of plasminogen activator with those of other cAMP-regulated genes, we identify a 29-nucleotide sequence that is tentatively proposed as the cAMP-regulatory unit. Homologous sequences are present (i) in the cAMP-regulated rat tyrosine aminotransferase, prolactin, and phosphoenolpyruvate carboxykinase genes and (ii) 5' to the transcription initiation sites of cAMP-regulated Escherichia coli genes. From this we conclude that the expression of cAMP-responsive genes in higher eukaryotes may be controlled, as in E. coli, by proteins that form complexes with cAMP and then show sequence-specific DNA-binding properties. The complex formed by cAMP and the regulatory subunit of the type II mammalian protein kinase might be one candidate for this function. Based on several homologies we suggest that this subunit may have retained both the DNA-binding specificity and transcription-regulating properties in addition to the nucleotide-binding domains of the bacterial cAMP-binding protein. If this were so, dissociation of protein kinase by cAMP would activate two processes: (i) protein phosphorylation by the catalytic subunit and (ii) transcription regulation by the regulatory subunit. PMID:2991882

  18. Constitutive Activation of the Aromatic Hydrocarbon Receptor

    PubMed Central

    Chang, Ching-Yi; Puga, Alvaro

    1998-01-01

    The ligand-activated aromatic hydrocarbon receptor (AHR) dimerizes with the AHR nuclear translocator (ARNT) to form a functional complex that transactivates expression of the cytochrome P-450 CYP1A1 gene and other genes in the dioxin-inducible [Ah] gene battery. Previous work from this laboratory has shown that the activity of the CYP1A1 enzyme negatively regulates this process. To study the relationship between CYP1A1 activity and Ah receptor activation we used CYP1A1-deficient mouse hepatoma c37 cells and CYP1A1- and AHR-deficient African green monkey kidney CV-1 cells. Using gel mobility shift and luciferase reporter gene expression assays, we found that c37 cells that had not been exposed to exogenous Ah receptor ligands already contained transcriptionally active AHR-ARNT complexes, a finding that we also observed in wild-type Hepa-1 cells treated with Ellipticine, a CYP1A1 inhibitor. In CV-1 cells, transient expression of AHR and ARNT leads to high levels of AHR–ARNT-dependent luciferase gene expression even in the absence of an agonist. Using a green fluorescent protein-tagged AHR, we showed that elevated reporter gene expression correlates with constitutive nuclear localization of the AHR. Transcriptional activation of the luciferase reporter gene observed in CV-1 cells is significantly decreased by (i) expression of a functional CYP1A1 enzyme, (ii) competition with chimeric or truncated AHR proteins containing the AHR ligand-binding domain, and (iii) treatment with the AHR antagonist α-naphthoflavone. These results suggest that a CYP1A1 substrate, which accumulates in cells lacking CYP1A1 enzymatic activity, is an AHR ligand responsible for endogenous activation of the Ah receptor. PMID:9418899

  19. Cotinine in Human Placenta Predicts Induction of Gene Expression in Fetal Tissues

    PubMed Central

    Riffel, Amanda K.; Haley, Kathleen J.; Sharma, Sunita; Dai, Hongying; Tantisira, Kelan G.; Weiss, Scott T.; Leeder, J. Steven

    2013-01-01

    Maternal cigarette smoking during pregnancy is associated with increased risk of perinatal morbidity and mortality. However, the mechanisms underlying adverse birth outcomes following prenatal exposure to cigarette smoke remain unknown due, in part, to the absence or unreliability of information regarding maternal cigarette smoke exposure during pregnancy. Our goal was to determine if placental cotinine could be a reliable biomarker of fetal cigarette smoke exposure during pregnancy. Cotinine levels were determined in placentas from 47 women who reported smoking during pregnancy and from 10 women who denied cigarette smoke exposure. Cotinine levels were significantly higher in placentas from women reporting cigarette smoking (median = 27.2 ng/g) versus women who reported no smoke exposure (2.3 ng/g, P < 0.001). Receiver operating characteristic curve analysis identified an optimal cut point of 7.5 ng/g (sensitivity = 78.7%, specificity = 100%) to classify placenta samples from mothers who smoked versus those from mothers who did not. Among 415 placentas for which maternal cigarette smoking status was unavailable, 167 had cotinine levels > 7.5 ng/g and would be considered positive for cigarette smoke exposure. Data from quantitative reverse-transcription polymerase chain reaction analyses demonstrated that in utero cigarette smoke exposure predicted by cotinine in placenta is associated with changes in the expression of xenobiotic-metabolizing enzymes in fetal tissues. CYP1A1 mRNA in fetal lung and liver tissue and CYP1B1 mRNA in fetal lung tissue were significantly induced when cotinine was detected in placenta. These findings indicate that cotinine in placenta is a reliable biomarker for fetal exposure and response to maternal cigarette smoking during pregnancy. PMID:23209192

  20. Acute doxorubicin cardiotoxicity alters cardiac cytochrome P450 expression and arachidonic acid metabolism in rats

    SciTech Connect

    Zordoky, Beshay N.M.; Anwar-Mohamed, Anwar; Aboutabl, Mona E.

    2010-01-01

    Doxorubicin (DOX) is a potent anti-neoplastic antibiotic used to treat a variety of malignancies; however, its use is limited by dose-dependent cardiotoxicity. Moreover, there is a strong correlation between cytochrome P450 (CYP)-mediated arachidonic acid metabolites and the pathogenesis of many cardiovascular diseases. Therefore, in the current study, we have investigated the effect of acute DOX toxicity on the expression of several CYP enzymes and their associated arachidonic acid metabolites in the heart of male Sprague-Dawley rats. Acute DOX toxicity was induced by a single intraperitoneal injection of 15 mg/kg of the drug. Our results showed that DOX treatment for 24 h caused a significant induction of CYP1A1, CYP1B1, CYP2C11, CYP2J3, CYP4A1, CYP4A3, CYP4F1, CYP4F4, and EPHX2 gene expression in the heart of DOX-treated rats as compared to the control. Similarly, there was a significant induction of CYP1A1, CYP1B1, CYP2C11, CYP2J3, CYP4A, and sEH proteins after 24 h of DOX administration. In the heart microsomes, acute DOX toxicity significantly increased the formation of 20-HETE which is consistent with the induction of the major CYP omega-hydroxylases: CYP4A1, CYP4A3, CYP4F1, and CYP4F4. On the other hand, the formation of 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids (EETs) was significantly reduced, whereas the formation of their corresponding dihydroxyeicosatrienoic acids was significantly increased. The decrease in the cardioprotective EETs can be attributed to the increase of sEH activity parallel to the induction of the EPHX2 gene expression in the heart of DOX-treated rats. In conclusion, acute DOX toxicity alters the expression of several CYP and sEH enzymes with a consequent alteration in arachidonic acid metabolism. These results may represent a novel mechanism by which this drug causes progressive cardiotoxicity.

  1. Differential expression of the ras gene family in mice.

    PubMed Central

    Leon, J; Guerrero, I; Pellicer, A

    1987-01-01

    We compared the expression of the ras gene family (H-ras, K-ras, and N-ras) in adult mouse tissues and during development. We found substantial variations in expression among different organs and in the amounts of the different transcripts originating from each gene, especially for the N-ras gene. The expression patterns were consistent with the reported preferential tissue activation of ras genes and suggested different cellular functions for each of the ras genes. Images PMID:3600635

  2. Cytochrome P450 expression and activities in human tongue cells and their modulation by green tea extract

    SciTech Connect

    Yang, S.-P.; Raner, Gregory M. . E-mail: gmraner@uncg.edu

    2005-01-15

    The expression, inducibility, and activities of several cytochrome P450 (CYP) enzymes were investigated in a human tongue carcinoma cell model, CAL 27, and compared with the human liver model HepG2 cells. The modulation effects of green tea on various CYP isoforms in both cell lines were also examined. RT-PCR analysis of CAL 27 cells demonstrated constitutive expression of mRNA for CYPs 1A1, 1A2, 2C, 2E1, 2D6, and 4F3. The results were negative for CYP2A6, 2B6/7, 3A3/4, and 3A7. Both cell lines displayed identical expression and induction profiles for all of the isoforms examined in this study except 3A7 and 2B6/7, which were produced constitutively in HepG2 but not Cal-27 cells. CYP1A1 and 1A2 were both induced by treatment with {beta}-napthoflavone as indicated by RT-PCR and Western blotting, while CYP2C mRNA was upregulated by all-trans retinoic acid and farnesol. RT-PCR and Western blot analysis showed that the expressions of CYP1A1 and 1A2 were induced by green tea extract (GTE), which also caused an increase in mRNA for CYP2E1, CYP2D6, and CYP2C isoforms. The four tea catechins, EGC, EC, EGCG and ECG, applied to either HepG2 or Cal-27 cells at the concentration found in GTE failed to induce CYP1A1 or CYP1A2, as determined by RT-PCR. Of the isoforms that were apparently induced by GTE, only 7-ethoxycoumarin deethylase (ECOD) activity could be detected in CAL 27 or HepG2 cells. Interestingly, mRNA and protein for CYP1A1 and CYP1A2 were detected in both cell lines, and although protein and mRNA levels of CYP1A1 and CYP1A2 were increased by GTE, the observed ECOD activity in both cell lines was decreased.

  3. Studying the complex expression dependences between sets of coexpressed genes.

    PubMed

    Huerta, Mario; Casanova, Oriol; Barchino, Roberto; Flores, Jose; Querol, Enrique; Cedano, Juan

    2014-01-01

    Organisms simplify the orchestration of gene expression by coregulating genes whose products function together in the cell. The use of clustering methods to obtain sets of coexpressed genes from expression arrays is very common; nevertheless there are no appropriate tools to study the expression networks among these sets of coexpressed genes. The aim of the developed tools is to allow studying the complex expression dependences that exist between sets of coexpressed genes. For this purpose, we start detecting the nonlinear expression relationships between pairs of genes, plus the coexpressed genes. Next, we form networks among sets of coexpressed genes that maintain nonlinear expression dependences between all of them. The expression relationship between the sets of coexpressed genes is defined by the expression relationship between the skeletons of these sets, where this skeleton represents the coexpressed genes with a well-defined nonlinear expression relationship with the skeleton of the other sets. As a result, we can study the nonlinear expression relationships between a target gene and other sets of coexpressed genes, or start the study from the skeleton of the sets, to study the complex relationships of activation and deactivation between the sets of coexpressed genes that carry out the different cellular processes present in the expression experiments.

  4. Covariance Structure Models for Gene Expression Microarray Data

    ERIC Educational Resources Information Center

    Xie, Jun; Bentler, Peter M.

    2003-01-01

    Covariance structure models are applied to gene expression data using a factor model, a path model, and their combination. The factor model is based on a few factors that capture most of the expression information. A common factor of a group of genes may represent a common protein factor for the transcript of the co-expressed genes, and hence, it…

  5. Gene Expression Omnibus: NCBI gene expression and hybridization array data repository.

    PubMed

    Edgar, Ron; Domrachev, Michael; Lash, Alex E

    2002-01-01

    The Gene Expression Omnibus (GEO) project was initiated in response to the growing demand for a public repository for high-throughput gene expression data. GEO provides a flexible and open design that facilitates submission, storage and retrieval of heterogeneous data sets from high-throughput gene expression and genomic hybridization experiments. GEO is not intended to replace in house gene expression databases that benefit from coherent data sets, and which are constructed to facilitate a particular analytic method, but rather complement these by acting as a tertiary, central data distribution hub. The three central data entities of GEO are platforms, samples and series, and were designed with gene expression and genomic hybridization experiments in mind. A platform is, essentially, a list of probes that define what set of molecules may be detected. A sample describes the set of molecules that are being probed and references a single platform used to generate its molecular abundance data. A series organizes samples into the meaningful data sets which make up an experiment. The GEO repository is publicly accessible through the World Wide Web at http://www.ncbi.nlm.nih.gov/geo.

  6. Identification of novel TCDD-regulated genes by microarray analysis

    SciTech Connect

    Hanlon, Paul R.; Zheng, Wenchao; Ko, Alex Y.; Jefcoate, Colin R. . E-mail: jefcoate@facstaff.wisc.edu

    2005-02-01

    TCDD exposure of multipotential C3H10T1/2 fibroblasts for 72 h altered the expression of over 1000 genes, including coordinated changes across large functionally similar gene clusters. TCDD coordinately induced 23 cell cycle-related genes similar to epidermal growth factor (EGF)-induced levels but without any affect on the major mitogenic signaling pathway (extracellular signal-regulated kinase, ERK). TCDD treatment also decreased glycolytic and ribosomal clusters. Most of these TCDD-induced changes were attenuated by the presence of EGF or an adipogenic stimulus, each added during the final 24 h. TCDD prevented 10% of EGF-induced gene responses and 40% of adipogenic responses. Over 100 other genes responded to TCDD during adipogenesis. This group of responses included complete suppression of three proliferins and stimulations of several cytokine receptors. Despite these varied secondary effects of TCDD, direct AhR activation measured by integrated AhR-responsive luciferase reporters was similar under quiescent, EGF-stimulated or adipogenic conditions. Only 23 genes were similarly induced by TCDD regardless of conditions and 10 were suppressed. These 23 genes include: 4 genes previously recognized to contain AhR response elements (cytochrome P450 (CYP) 1B1, CYP1A1, NAD(P)H quinone reductase 1 (NQO1), and aldehyde dehydrogenase 3A1); two novel oxidative genes (alcohol dehydrogenase 3 and superoxide dismutase 3); and glypican 1, a plasma membrane proteoglycan that affects cell signaling. Further experiments demonstrated that TCDD maximally induced NQO1, glypican 1 and alcohol dehydrogenase 3 by 6 h. Glypican 1 activates the actions of many growth factors and therefore may contribute to secondary effects on gene expression.

  7. Novel recombinant papillomavirus genomes expressing selectable genes

    PubMed Central

    Van Doorslaer, Koenraad; Porter, Samuel; McKinney, Caleb; Stepp, Wesley H.; McBride, Alison A.

    2016-01-01

    Papillomaviruses infect and replicate in keratinocytes, but viral proteins are initially expressed at low levels and there is no effective and quantitative method to determine the efficiency of infection on a cell-to-cell basis. Here we describe human papillomavirus (HPV) genomes that express marker proteins (antibiotic resistance genes and Green Fluorescent Protein), and can be used to elucidate early stages in HPV infection of primary keratinocytes. To generate these recombinant genomes, the late region of the oncogenic HPV18 genome was replaced by CpG free marker genes. Insertion of these exogenous genes did not affect early replication, and had only minimal effects on early viral transcription. When introduced into primary keratinocytes, the recombinant marker genomes gave rise to drug-resistant keratinocyte colonies and cell lines, which maintained the extrachromosomal recombinant genome long-term. Furthermore, the HPV18 “marker” genomes could be packaged into viral particles (quasivirions) and used to infect primary human keratinocytes in culture. This resulted in the outgrowth of drug-resistant keratinocyte colonies containing replicating HPV18 genomes. In summary, we describe HPV18 marker genomes that can be used to quantitatively investigate many aspects of the viral life cycle. PMID:27892937

  8. Nuclear AXIN2 represses MYC gene expression

    SciTech Connect

    Rennoll, Sherri A.; Konsavage, Wesley M.; Yochum, Gregory S.

    2014-01-03

    Highlights: •AXIN2 localizes to cytoplasmic and nuclear compartments in colorectal cancer cells. •Nuclear AXIN2 represses the activity of Wnt-responsive luciferase reporters. •β-Catenin bridges AXIN2 to TCF transcription factors. •AXIN2 binds the MYC promoter and represses MYC gene expression. -- Abstract: The β-catenin transcriptional coactivator is the key mediator of the canonical Wnt signaling pathway. In the absence of Wnt, β-catenin associates with a cytosolic and multi-protein destruction complex where it is phosphorylated and targeted for proteasomal degradation. In the presence of Wnt, the destruction complex is inactivated and β-catenin translocates into the nucleus. In the nucleus, β-catenin binds T-cell factor (TCF) transcription factors to activate expression of c-MYC (MYC) and Axis inhibition protein 2 (AXIN2). AXIN2 is a member of the destruction complex and, thus, serves in a negative feedback loop to control Wnt/β-catenin signaling. AXIN2 is also present in the nucleus, but its function within this compartment is unknown. Here, we demonstrate that AXIN2 localizes to the nuclei of epithelial cells within normal and colonic tumor tissues as well as colorectal cancer cell lines. In the nucleus, AXIN2 represses expression of Wnt/β-catenin-responsive luciferase reporters and forms a complex with β-catenin and TCF. We demonstrate that AXIN2 co-occupies β-catenin/TCF complexes at the MYC promoter region. When constitutively localized to the nucleus, AXIN2 alters the chromatin structure at the MYC promoter and directly represses MYC gene expression. These findings suggest that nuclear AXIN2 functions as a rheostat to control MYC expression in response to Wnt/β-catenin signaling.

  9. Inducible gene expression systems and plant biotechnology.

    PubMed

    Corrado, Giandomenico; Karali, Marianthi

    2009-01-01

    Plant biotechnology relies heavily on the genetic manipulation of crops. Almost invariantly, the gene of interest is expressed in a constitutive fashion, although this may not be strictly necessary for several applications. Currently, there are several regulatable expression systems for the temporal, spatial and quantitative control of transgene activity. These molecular switches are based on components derived from different organisms, which range from viruses to higher eukaryotes. Many inducible systems have been designed for fundamental and applied research and since their initial development, they have become increasingly popular in plant molecular biology. This review covers a broad number of inducible expression systems examining their properties and relevance for plant biotechnology in its various guises, from molecular breeding to pharmaceutical and industrial applications. For each system, we examine some advantages and limitations, also in relation to the strategy on which they rely. Besides being necessary to control useful genes that may negatively affect crop yield and quality, we discuss that inducible systems can be also used to increase public acceptance of GMOs, reducing some of the most common concerns. Finally, we suggest some directions and future developments for their further diffusion in agriculture and biotechnology.

  10. Combined clustering models for the analysis of gene expression

    SciTech Connect

    Angelova, M. Ellman, J.

    2010-02-15

    Clustering has become one of the fundamental tools for analyzing gene expression and producing gene classifications. Clustering models enable finding patterns of similarity in order to understand gene function, gene regulation, cellular processes and sub-types of cells. The clustering results however have to be combined with sequence data or knowledge about gene functionality in order to make biologically meaningful conclusions. In this work, we explore a new model that integrates gene expression with sequence or text information.

  11. Using PCR to Target Misconceptions about Gene Expression

    PubMed Central

    Wright, Leslie K.; Newman, Dina L.

    2013-01-01

    We present a PCR-based laboratory exercise that can be used with first- or second-year biology students to help overcome common misconceptions about gene expression. Biology students typically do not have a clear understanding of the difference between genes (DNA) and gene expression (mRNA/protein) and often believe that genes exist in an organism or cell only when they are expressed. This laboratory exercise allows students to carry out a PCR-based experiment designed to challenge their misunderstanding of the difference between genes and gene expression. Students first transform E. coli with an inducible GFP gene containing plasmid and observe induced and un-induced colonies. The following exercise creates cognitive dissonance when actual PCR results contradict their initial (incorrect) predictions of the presence of the GFP gene in transformed cells. Field testing of this laboratory exercise resulted in learning gains on both knowledge and application questions on concepts related to genes and gene expression. PMID:23858358

  12. Regulation of Airway Mucin Gene Expression

    PubMed Central

    Thai, Philip; Loukoianov, Artem; Wachi, Shinichiro; Wu, Reen

    2015-01-01

    Mucins are important components that exert a variety of functions in cell-cell interaction, epidermal growth factor receptor signaling, and airways protection. In the conducting airways of the lungs, mucins are the major contributor to the viscoelastic property of mucous secretion, which is the major barrier to trapping inhaled microbial organism, particulates, and oxidative pollutants. The homeostasis of mucin production is an important feature in conducting airways for the maintenance of mucociliary function. Aberrant mucin secretion and accumulation in airway lumen are clinical hallmarks associated with various lung diseases, such as asthma, chronic obstructive pulmonary disease, cystic fibrosis, emphysema, and lung cancer. Among 20 known mucin genes identified, 11 of them have been verified at either the mRNA and/or protein level in airways. The regulation of mucin genes is complicated, as are the mediators and signaling pathways. This review summarizes the current view on the mediators, the signaling pathways, and the transcriptional units that are involved in the regulation of airway mucin gene expression. In addition, we also point out essential features of epigenetic mechanisms for the regulation of these genes. PMID:17961085

  13. RNA-Sequencing studies identify genes differentially regulated during inflammation-driven lung tumorigenesis and targeted by chemopreventive agents

    PubMed Central

    Qian, Xuemin; Khammanivong, Ali; Song, Jung Min; Teferi, Fitsum; Upadhyaya, Pramod; Dickerson, Erin; Kassie, Fekadu

    2016-01-01

    Chronic pulmonary inflammation has been consistently shown to increase the risk of lung cancer. Therefore, assessing the molecular links between the two diseases and identification of chemopreventive agents that inhibit inflammation-driven lung tumorigenesis is indispensable. Recently, we found that 4-(methylnitro-samino)-1-(3-pyridyl)-1-butanone (NNK)-induced mouse lung tumorigenesis was significantly enhanced by chronic treatment with the inflammatory agents lipopolysaccharide (LPS) and combinatory treatment with the chemoprevenitve agents silibinin (Sil) and indole-3-carbinol (I3C) significantly inhibited the burden of inflammation-driven lung tumors. In this report, we described gene expression profiling of lung tissues derived from these studies to determine the gene expression signature in inflammation-driven lung tumors and modulation of this signature by the chemopreventive agents Sil and I3C. We found that 330, 2,957, and 1,143 genes were differentially regulated in mice treated with NNK, LPS, and NNK + LPS, respectively. The inflammatory response of lung tumors to LPS, as determined by the number of proinflammatory genes with altered gene expression or the level of alteration, was markedly less than that of normal lungs. Among 1,143 genes differentially regulated in the NNK + LPS group, the expression of 162 genes and associated signaling pathways were significantly modulated by I3C and/or Sil + I3C. These genes include cytokines, chemokines, putative oncogenes and tumor suppressor genes and Ros1, AREG, EREG, Cyp1a1, Arntl, and Npas2. To our knowledge, this is the first report that provides insight into genes that are differentially expressed during inflammation-driven lung tumorigenesis and the modulation of these genes by chemopreventive agents. PMID:25795230

  14. Hyperbaric oxygen treatment induces antioxidant gene expression.

    PubMed

    Godman, Cassandra A; Joshi, Rashmi; Giardina, Charles; Perdrizet, George; Hightower, Lawrence E

    2010-06-01

    Although the underlying molecular causes of aging are not entirely clear, hormetic agents like exercise, heat, and calorie restriction may generate a mild pro-oxidant stress that induces cell protective responses to promote healthy aging. As an individual ages, many cellular and physiological processes decline, including wound healing and reparative angiogenesis. This is particularly critical in patients with chronic non-healing wounds who tend to be older. We are interested in the potential beneficial effects of hyperbaric oxygen as a mild hormetic stress on human microvascular endothelial cells. We analyzed global gene expression changes in human endothelial cells following a hyperbaric exposure comparable to a clinical treatment. Our analysis revealed an upregulation of antioxidant, cytoprotective, and immediate early genes. This increase coincided with an increased resistance to a lethal oxidative stress. Our data indicate that hyperbaric oxygen can induce protection against oxidative insults in endothelial cells and may provide an easily administered hormetic treatment to help promote healthy aging.

  15. Expressing exogenous genes in newts by transgenesis.

    PubMed

    Casco-Robles, Martin Miguel; Yamada, Shouta; Miura, Tomoya; Nakamura, Kenta; Haynes, Tracy; Maki, Nobuyasu; Del Rio-Tsonis, Katia; Tsonis, Panagiotis A; Chiba, Chikafumi

    2011-05-01

    The great regenerative abilities of newts provide the impetus for studies at the molecular level. However, efficient methods for gene regulation have historically been quite limited. Here we describe a protocol for transgenically expressing exogenous genes in the newt Cynops pyrrhogaster. This method is simple: a reaction mixture of I-SceI meganuclease and a plasmid DNA carrying a transgene cassette flanked by the enzyme recognition sites is directly injected into fertilized eggs. The protocol achieves a high efficiency of transgenesis, comparable to protocols used in other animal systems, and it provides a practical number of transgenic newts (∼20% of injected embryos) that survive beyond metamorphosis and that can be applied to regenerative studies. The entire protocol for obtaining transgenic adult newts takes 4-5 months.

  16. Gene expression signatures in lymphoid tumours.

    PubMed

    Kees, Ursula R

    2004-04-01

    Lymphoid tumours comprise the acute and chronic leukaemias, the broad spectrum of lymphomas, including Hodgkin's disease, and multiple myeloma. The subdivision of the acute leukaemias according to the proliferating type of white blood cells has had a major impact on the care of these patients. More recently, specific chromosomal translocations have been used to identify patients who may benefit from more intensive therapies. The novel high-throughput genomic technologies, such as microarrays, provide new avenues for the molecular diagnosis of the haematological malignancies. Rapid advances in genome sequencing and gene expression profiling provide unprecedented opportunities to identify specific genes involved in complex biological processes, including tumorigenesis. The features of microarray technology and the variety of experimental approaches to elucidate lymphoid malignancies are discussed. Microarray technology has the potential to lead to more accurate prognostic assessment for patients and is expected to ultimately allow the clinician to select therapies optimally suited to each patient.

  17. Retrotransposons as regulators of gene expression.

    PubMed

    Elbarbary, Reyad A; Lucas, Bronwyn A; Maquat, Lynne E

    2016-02-12

    Transposable elements (TEs) are both a boon and a bane to eukaryotic organisms, depending on where they integrate into the genome and how their sequences function once integrated. We focus on two types of TEs: long interspersed elements (LINEs) and short interspersed elements (SINEs). LINEs and SINEs are retrotransposons; that is, they transpose via an RNA intermediate. We discuss how LINEs and SINEs have expanded in eukaryotic genomes and contribute to genome evolution. An emerging body of evidence indicates that LINEs and SINEs function to regulate gene expression by affecting chromatin structure, gene transcription, pre-mRNA processing, or aspects of mRNA metabolism. We also describe how adenosine-to-inosine editing influences SINE function and how ongoing retrotransposition is countered by the body's defense mechanisms.

  18. Gene expression-targeted isoflavone therapy.

    PubMed

    Węgrzyn, Alicja

    2012-04-01

    Lysosomal storage diseases (LSD) form a group of inherited metabolic disorders caused by dysfunction of one of the lysosomal proteins, resulting in the accumulation of certain compounds. Although these disorders are among first genetic diseases for which specific treatments were proposed, there are still serious unsolved problems that require development of novel therapeutic procedures. An example is neuronopathy, which develops in most of LSD and cannot be treated efficiently by currently approved therapies. Recently, a new potential therapy, called gene expression-targeted isoflavone therapy (GET IT), has been proposed for a group of LSD named mucopolysaccharidoses (MPS), in which storage of incompletely degraded glycosaminoglycans (GAGs) results in severe symptoms of virtually all tissues and organs, including central nervous system. The idea of this therapy is to inhibit synthesis of GAGs by modulating expression of genes coding for enzymes involved in synthesis of these compounds. Such a modulation is possible by using isoflavones, particularly genistein, which interfere with a signal transduction process necessary for stimulation of expression of certain genes. Results of in vitro experiments and studies on animal models indicated a high efficiency of GET IT, including correction of behavior of affected mice. However, clinical trials, performed with soy isoflavone extracts, revealed only limited efficacy. This caused a controversy about GET IT as a potential, effective treatment of patients suffering from MPS, especially neuronopathic forms of these diseases. It this critical review, I present possible molecular mechanisms of therapeutic action of isoflavones (particularly genistein) and suggest that efficacy of GET IT might be sufficiently high when using relatively high doses of synthetic genistein (which was employed in experiments on cell cultures and mouse models) rather than low doses of soy isoflavone extracts (which were used in clinical trials). This

  19. Maternal diet programs embryonic kidney gene expression.

    PubMed

    Welham, Simon J M; Riley, Paul R; Wade, Angie; Hubank, Mike; Woolf, Adrian S

    2005-06-16

    Human epidemiological data associating birth weight with adult disease suggest that organogenesis is "programmed" by maternal diet. In rats, protein restriction in pregnancy produces offspring with fewer renal glomeruli and higher systemic blood pressures than controls. We tested the hypothesis that maternal diet alters gene expression in the metanephros, the precursor of the definitive mammalian kidney. We demonstrated that maternal low-protein diet initiated when pregnancy starts and maintained to embryonic day 13, when the metanephros consists of mesenchyme surrounding a once-branched ureteric bud, is sufficient to significantly reduce glomerular numbers in offspring by about 20%. As assessed by representational difference analyses and real-time quantitative polymerase chain reactions, low-protein diet modulated gene expression in embryonic day 13 metanephroi. In particular, levels of prox-1, the ortholog of Drosophila transcription factor prospero, and cofilin-1, a regulator of the actin cytoskeleton, were reduced. During normal metanephrogenesis, prox-1 protein was first detected in mesenchymal cells around the ureteric tree and thereafter in nascent nephron epithelia, whereas cofilin-1 immunolocalized to bud derivatives and condensing mesenchyme. Previously, we reported that low-protein diets increased mesenchymal apoptosis cells when metanephrogenesis began and thereafter reduced numbers of precursor cells. Collectively, these studies prove that the maternal diet programs the embryonic kidney, altering cell turnover and gene expression at a time when nephrons and glomeruli have yet to form. The human implication is that the maternal diet ingested between conception and 5- 6-wk gestation contributes to the variation in glomerular numbers that are known to occur between healthy and hypertensive populations.

  20. Cytochrome P450 1b1 in polycyclic aromatic hydrocarbon (PAH)-induced skin carcinogenesis: Tumorigenicity of individual PAHs and coal-tar extract, DNA adduction and expression of select genes in the Cyp1b1 knockout mouse

    SciTech Connect

    Siddens, Lisbeth K.; Bunde, Kristi L.; Harper, Tod A.; McQuistan, Tammie J.; Löhr, Christiane V.; Bramer, Lisa M.; Waters, Katrina M.; Tilton, Susan C.; Krueger, Sharon K.; and others

    2015-09-01

    FVB/N mice wild-type, heterozygous or null for Cyp 1b1 were used in a two-stage skin tumor study comparing PAH, benzo[a]pyrene (BaP), dibenzo[def,p]chrysene (DBC), and coal tar extract (CTE, SRM 1597a). Following 20 weeks of promotion with TPA the Cyp 1b1 null mice, initiated with DBC, exhibited reductions in incidence, multiplicity, and progression. None of these effects were observed with BaP or CTE. The mechanism of Cyp 1b1-dependent alteration of DBC skin carcinogenesis was further investigated by determining expression of select genes in skin from DBC-treated mice 2, 4 and 8 h post-initiation. A significant reduction in levels of Cyp 1a1, Nqo1 at 8 h and Akr 1c14 mRNA was observed in Cyp 1b1 null (but not wt or het) mice, whereas no impact was observed in Gst a1, Nqo 1 at 2 and 4 h or Akr 1c19 at any time point. Cyp 1b1 mRNA was not elevated by DBC. The major covalent DNA adducts, dibenzo[def,p]chrysene-(±)-11,12-dihydrodiol-cis and trans-13,14-epoxide-deoxyadenosine (DBCDE-dA) were quantified by UHPLC-MS/MS 8 h post-initiation. Loss of Cyp1 b1 expression reduced DBCDE-dA adducts in the skin but not to a statistically significant degree. The ratio of cis- to trans-DBCDE-dA adducts was higher in the skin than other target tissues such as the spleen, lung and liver (oral dosing). These results document that Cyp 1b1 plays a significant role in bioactivation and carcinogenesis of DBC in a two-stage mouse skin tumor model and that loss of Cyp 1b1 has little impact on tumor response with BaP or CTE as initiators. - Highlights: • Cyp1b1 null mice exhibit lower skin cancer sensitivity to DBC but not BaP or CTE. • Cyp1b1 expression impacts expression of other PAH metabolizing enzymes. • cis/trans-DBCDE-dA ratio significantly higher in the skin than the spleen, lung or liver • Potency of DBC and CTE in mouse skin is higher than predicted by RPFs.

  1. Pathway network inference from gene expression data

    PubMed Central

    2014-01-01

    Background The development of high-throughput omics technologies enabled genome-wide measurements of the activity of cellular elements and provides the analytical resources for the progress of the Systems Biology discipline. Analysis and interpretation of gene expression data has evolved from the gene to the pathway and interaction level, i.e. from the detection of differentially expressed genes, to the establishment of gene interaction networks and the identification of enriched functional categories. Still, the understanding of biological systems requires a further level of analysis that addresses the characterization of the interaction between functional modules. Results We present a novel computational methodology to study the functional interconnections among the molecular elements of a biological system. The PANA approach uses high-throughput genomics measurements and a functional annotation scheme to extract an activity profile from each functional block -or pathway- followed by machine-learning methods to infer the relationships between these functional profiles. The result is a global, interconnected network of pathways that represents the functional cross-talk within the molecular system. We have applied this approach to describe the functional transcriptional connections during the yeast cell cycle and to identify pathways that change their connectivity in a disease condition using an Alzheimer example. Conclusions PANA is a useful tool to deepen in our understanding of the functional interdependences that operate within complex biological systems. We show the approach is algorithmically consistent and the inferred network is well supported by the available functional data. The method allows the dissection of the molecular basis of the functional connections and we describe the different regulatory mechanisms that explain the network's topology obtained for the yeast cell cycle data. PMID:25032889

  2. Altered gene expression correlates with DNA structure.

    PubMed

    Kohwi, Y; Kohwi-Shigematsu, T

    1991-12-01

    We examined the participation of triplex DNA structure in gene regulation using a poly(dG)-poly(dC) sequence as a model. We show that a poly(dG)-poly(dC) sequence, which can adopt an intramolecular dG.dG.dC triplex under superhelical strain, strongly augments gene expression when placed 5' to a promoter. The activity of this sequence exhibits a striking length dependency: dG tracts of 27-30 bp augment the expression of a reporter gene to a level comparable to that observed with the polyoma enhancer in mouse LTK- cells, whereas tracts of 35 bp and longer have virtually no effect. A supercoiled plasmid containing a dG tract of 30 bp competes in vivo for a trans-acting factor as revealed by reduction in the reporter gene transcription driven by the (dG)29/promoter of the test plasmid, while dGs of 35 bp and longer in the competition plasmid failed to compete. In purified supercoiled plasmid DNA at a superhelical density of -0.05, dG tracts of 32 bp and longer form a triplex, whereas those of 30 bp and shorter remain double-stranded under a PBS solution. These results suggest that a localized superhelical strain can exist, at least transiently, in mouse LTK- cells, and before being relaxed by topoisomerases this rapidly induces dG tracts of 35 bp and longer to adopt a triplex preventing the factor from binding. Thus, these data suggest that a poly(dG)-poly(dC) sequence can function as a negative regulator by adopting an intramolecular triple helix structure in vivo.

  3. Gene expression profiling of cytochromes P450, ABC transporters and their principal transcription factors in the amygdala and prefrontal cortex of alcoholics, smokers and drug-free controls by qRT-PCR.

    PubMed

    Toselli, Francesca; de Waziers, Isabelle; Dutheil, Mary; Vincent, Marc; Wilce, Peter A; Dodd, Peter R; Beaune, Philippe; Loriot, Marie-Anne; Gillam, Elizabeth M J

    2015-01-01

    1. Ethanol consumption and smoking alter the expression of certain drug-metabolizing enzymes and transporters, potentially influencing the tissue-specific effects of xenobiotics. 2. Amygdala (AMG) and prefrontal cortex (PFC) are brain regions that modulate the effects of alcohol and smoking, yet little is known about the expression of cytochrome P450 enzymes (P450s) and ATP-binding cassette (ABC) transporters in these tissues. 3. Here, we describe the first study on the expression of 19 P450s, their redox partners, three ABC transporters and four related transcription factors in the AMG and PFC of smokers and alcoholics by quantitative RT-PCR. 4. CYP1A1, CYP1B1, CYP2B6, CYP2C8, CYP2C18, CYP2D6, CYP2E1, CYP2J2, CYP2S1, CYP2U1, CYP4X1, CYP46, adrenodoxin and NADPH-P450 reductase, ABCB1, ABCG2, ABCA1, and transcription factors aryl hydrocarbon receptor AhR and proliferator-activated receptor α were quantified in both areas. CYP2A6, CYP2C9, CYP2C19, CYP3A4, CYP3A5, adrenodoxin reductase and the nuclear receptors pregnane X receptor and constitutive androstane receptor were detected but below the limit of quantification. CYP1A2 and CYP2W1 were not detected. 5. Adrenodoxin expression was elevated in all case groups over controls, and smokers showed a trend toward higher CYP1A1 and CYP1B1 expression. 6. Our study shows that most xenobiotic-metabolizing P450s and associated redox partners, transporters and transcription factors are expressed in human AMG and PFC.

  4. Dynamics of single-cell gene expression

    PubMed Central

    Longo, Diane; Hasty, Jeff

    2006-01-01

    Cellular behavior has traditionally been investigated by utilizing bulk-scale methods that measure average values for a population of cells. Such population-wide studies mask the behavior of individual cells and are often insufficient for characterizing biological processes in which cellular heterogeneity plays a key role. A unifying theme of many recent studies has been a focus on the development and utilization of single-cell experimental techniques that are capable of probing key biological phenomena in individual living cells. Recently, novel information about gene expression dynamics has been obtained from single-cell experiments that draw upon the unique capabilities of fluorescent reporter proteins. PMID:17130866

  5. Solid state nanopores for gene expression profiling

    NASA Astrophysics Data System (ADS)

    Mussi, V.; Fanzio, P.; Repetto, L.; Firpo, G.; Valbusa, U.; Scaruffi, P.; Stigliani, S.; Tonini, G. P.

    2009-07-01

    Recently, nanopore technology has been introduced for genome analysis. Here we show results related to the possibility of preparing "engineered solid state nanopores". The nanopores were fabricated on a suspended Si 3N 4 membrane by Focused Ion Beam (FIB) drilling and chemically functionalized in order to covalently bind oligonucleotides (probes) on their surface. Our data show the stable effect of DNA attachment on the ionic current measured through the nanopore, making it possible to conceive and develop a selective biosensor for gene expression profiling.

  6. Clinical diagnostic gene expression thyroid testing.

    PubMed

    Steward, David L; Kloos, Richard T

    2014-08-01

    Thyroid fine-needle aspiration biopsies are cytologically indeterminate in 15% to 30% of cases. When cytologically indeterminate thyroid nodules undergo diagnostic surgery, approximately three-quarters prove to be histologically benign. A negative predictive value of more than or equal to 94% for the Afirma Gene Expression Classifier (GEC) is achieved for indeterminate nodules. Most Afirma GEC benign nodules can be clinically observed, as suggested by the National Comprehensive Cancer Network Thyroid Carcinoma Guideline. More than half of the benign nodules with indeterminate cytology (Bethesda categories III/IV) can be identified as GEC benign and removed from the surgical pool to prevent unnecessary diagnostic surgery.

  7. Clustering gene expression data using graph separators.

    PubMed

    Kaba, Bangaly; Pinet, Nicolas; Lelandais, Gaëlle; Sigayret, Alain; Berry, Anne

    2007-01-01

    Recent work has used graphs to modelize expression data from microarray experiments, in view of partitioning the genes into clusters. In this paper, we introduce the use of a decomposition by clique separators. Our aim is to improve the classical clustering methods in two ways: first we want to allow an overlap between clusters, as this seems biologically sound, and second we want to be guided by the structure of the graph to define the number of clusters. We test this approach with a well-known yeast database (Saccharomyces cerevisiae). Our results are good, as the expression profiles of the clusters we find are very coherent. Moreover, we are able to organize into another graph the clusters we find, and order them in a fashion which turns out to respect the chronological order defined by the the sporulation process.

  8. Gene expression during the life cycle of Drosophila melanogaster.

    PubMed

    Arbeitman, Michelle N; Furlong, Eileen E M; Imam, Farhad; Johnson, Eric; Null, Brian H; Baker, Bruce S; Krasnow, Mark A; Scott, Matthew P; Davis, Ronald W; White, Kevin P

    2002-09-27

    Molecular genetic studies of Drosophila melanogaster have led to profound advances in understanding the regulation of development. Here we report gene expression patterns for nearly one-third of all Drosophila genes during a complete time course of development. Mutations that eliminate eye or germline tissue were used to further analyze tissue-specific gene expression programs. These studies define major characteristics of the transcriptional programs that underlie the life cycle, compare development in males and females, and show that large-scale gene expression data collected from whole animals can be used to identify genes expressed in particular tissues and organs or genes involved in specific biological and biochemical processes.

  9. Gene Expression During the Life Cycle of Drosophila melanogaster

    NASA Astrophysics Data System (ADS)

    Arbeitman, Michelle N.; Furlong, Eileen E. M.; Imam, Farhad; Johnson, Eric; Null, Brian H.; Baker, Bruce S.; Krasnow, Mark A.; Scott, Matthew P.; Davis, Ronald W.; White, Kevin P.

    2002-09-01

    Molecular genetic studies of Drosophila melanogaster have led to profound advances in understanding the regulation of development. Here we report gene expression patterns for nearly one-third of all Drosophila genes during a complete time course of development. Mutations that eliminate eye or germline tissue were used to further analyze tissue-specific gene expression programs. These studies define major characteristics of the transcriptional programs that underlie the life cycle, compare development in males and females, and show that large-scale gene expression data collected from whole animals can be used to identify genes expressed in particular tissues and organs or genes involved in specific biological and biochemical processes.

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