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PloS One Apr 2011As an addictive substance, nicotine has been suggested to facilitate pro-survival activities (such as anchorage-independent growth or angiogenesis) and the establishment...
As an addictive substance, nicotine has been suggested to facilitate pro-survival activities (such as anchorage-independent growth or angiogenesis) and the establishment of drug resistance to anticancer therapy. Tobacco smoking consists of a variety of carcinogens [such as benzopyrene (BP) and nitrosamine derivatives] that are able to cause DNA double strand breaks. However, the effect of nicotine on DNA damage-induced checkpoint response induced by genotoxins remains unknown. In this study, we investigated the events occurred during G(1) arrest induced by γ-radiation or BP in nicotine-treated murine or human lung epithelial cells. DNA synthesis was rapidly inhibited after exposure to γ-radiation or BP treatment, accompanied with the activation of DNA damage checkpoint. When these cells were co-treated with nicotine, the growth restriction was compromised, manifested by upregulation of cyclin D and A, and attenuation of Chk2 phosphorylation. Knockdown of cyclin D or Chk2 by the siRNAs blocked nicotine-mediated effect on DNA damage checkpoint activation. However, nicotine treatment appeared to play no role in nocodazole-induced mitotic checkpoint activation. Overall, our study presented a novel observation, in which nicotine is able to override DNA damage checkpoint activated by tobacco-related carcinogen BP or γ-irradiation. The results not only indicates the potentially important role of nicotine in facilitating the establishment of genetic instability to promote lung tumorigenesis, but also warrants a dismal prognosis for cancer patients who are smokers, heavily exposed second-hand smokers or nicotine users.
Topics: Animals; Benzopyrenes; Carcinogens; Cyclin A; Cyclin D1; DNA Damage; Epithelial Cells; G1 Phase; Gamma Rays; Ganglionic Stimulants; Humans; Lung; Mice; Mutation; Nicotine; Nocodazole; Phosphorylation; S Phase
PubMed: 21559516
DOI: 10.1371/journal.pone.0018619 -
BMC Pediatrics Jan 2014Asthma is the most common chronic childhood disease. Imbalance of cytokines released from T helper cells and environmental factors, such as exposure to poly-aromatic...
BACKGROUND
Asthma is the most common chronic childhood disease. Imbalance of cytokines released from T helper cells and environmental factors, such as exposure to poly-aromatic hydrocarbon (PAH), play pivotal roles in the pathogenesis of asthma. The aim of this study was to compare the mRNA expression patterns of Interleukin (IL)-4, interferon (IFN)-γ and Acyl Co A long chain 3 (ACSL3) in peripheral blood leukocytes of children with and without asthma. To correlate the obtained mRNA data with serum IL-4, IFN-γ and PAH levels. Further, to determine the effect of in vivo exposure to PAH on mRNA expression of IL-4, IFN-γ and ACSL3 genes in a rat model.
METHODS
A total of 170 children below 16 years (85 pediatric asthma patients and 85 matched healthy controls) were randomly selected from the Riyadh Cohort, Saudi Arabia. Gene expression analysis was performed using qRTPCR. Serum IL-4, IFN-γ and PAH were measured using LINCOplex (human multiplex immunoassay kit) and HPLC respectively.
RESULTS
IL-4 mRNA expression was significantly increased (P < 0.05) in children with asthma compared to healthy control group whereas no differences were observed for either IFN-γ or ACSL3 mRNA. Similarly, serum IL- 4 and PAHs concentration was significantly higher as well in children with asthma in whom IFN-γ was also significantly lower. Results obtained in rats showed that exposure to the benzopyrene prototype PAH resulted in a 2.6 fold (P < 0.001) increased IL-4 mRNA expression in blood.
CONCLUSION
Peripheral blood IL-4 mRNA levels, serum concentration of this cytokine are elevated in children with asthma. Also, elevated levels of PAH were observed in children with asthma. Additionally, PAH administration in rodents resulted in an increased IL-4 mRNA which is supposed to partly mediate the inflammatory response noted in asthma.
Topics: Acyl Coenzyme A; Adolescent; Animals; Asthma; Benzopyrenes; Child; Cross-Sectional Studies; Humans; Interferon-gamma; Interleukin-4; Monocytes; RNA, Messenger; Rats; Rats, Wistar
PubMed: 24450480
DOI: 10.1186/1471-2431-14-17 -
Proceedings of the National Academy of... Jul 1978Highly purified cytochromes P-450(LM2) and P-450(LM4) and partially purified P-450(LM1), P-450(LM3b), and P-450(LM7) from rabbit liver microsomes exhibit different...
Regio- and stereoselectivity of various forms of purified cytochrome P-450 in the metabolism of benzo[a]pyrene and (-) trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene as shown by product formation and binding to DNA.
Highly purified cytochromes P-450(LM2) and P-450(LM4) and partially purified P-450(LM1), P-450(LM3b), and P-450(LM7) from rabbit liver microsomes exhibit different catalytic activities in the metabolism of benzo[a]pyrene (BzP) and (-)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene [(-)trans-7,8-diol] in a reconstituted enzyme system. The two highly purified cytochromes also exhibit differences in the activation of BzP and (-)trans-7,8-diol to intermediates that bind to DNA, as well as in the stereoselective conversion of (-)trans-7,8-diol to the highly mutagenic and carcinogenic diol-epoxides r-7,t-8-dihydroxy-t-9,10-oxy-7,8,9,10- tetrahydrobenzo[a]pyrene (diol-epoxide I) and r - 7,t - 8 - dihydroxy - c - 9,10 - oxy - 7,8,9,10 - tetrahydrobenzo[a]pyrene (diol-epoxide II). P-450(LM2) is more active than P-450(LM4) in the metabolism of BzP and in its conversion to products that bind to DNA. In contrast, P-450(LM4) is more active than P-450(LM2) in the metabolism of (-)trans-7,8-diol and in its conversion to products that bind to DNA. The ratio of activity (percent substrate metabolized) with BzP relative to that with (-)trans-7,8-diol is 21 for P-450(LM2) and 0.3 for P-450(LM4); P-450(LM1), P-450(LM3b), and P-450(LM7) gave intermediate ratios. Marked stereoselectivity in the oxygenation of the (-)trans-7,8-diol to the highly mutagenic and putatively carcinogenic diol-epoxides I and II was observed with P-450(LM4), whereas the other preparations showed less selectivity. The ratio of diolepoxide I to diol-epoxide II ranges from 0.3 for P-450(LM7) to 11 for P-450(LM4). The substrate specificity and regio- and stereo-selectivity of the different forms of cytochrome P-450 may regulate the balance between activation and detoxification pathways of BzP and therefore determine the susceptibility of individual tissues, strains, and species to the carcinogenic action of BzP.
Topics: Animals; Benzopyrenes; Cytochrome P-450 Enzyme System; DNA; Epoxy Compounds; Microsomes, Liver; Mixed Function Oxygenases; Oxidoreductases; Rabbits; Stereoisomerism; Substrate Specificity
PubMed: 277915
DOI: 10.1073/pnas.75.7.3123 -
The Biochemical Journal Mar 1976A study was made of the nature and specificity of the increase in biphenyl 2-hydroxylase activity after preincubation of liver microsomal preparations with various... (Comparative Study)
Comparative Study
A study was made of the nature and specificity of the increase in biphenyl 2-hydroxylase activity after preincubation of liver microsomal preparations with various carcinogens in vitro. This enhancement of enzyme activity in vitro was investigated in mouse, hamster and rat, and although the rat appears to be atypical in the variation of the pattern of 2- and 4-hydroxylation with age, similar enhancements were detectable in each species examined. An increase in biphenyl 2-hydroxylase activity was apparent 2h after intraperitoneal administration of safrole or benzopyrene to mature Wistar albino rats and appeared to be similar in nature to that observed after preincubation of liver microsomal preparations with the same chemical in vitro. Investigation of other drug-metabolizing enzyme systems suggests that the enhancing effects of carcinogens in vitro are specific for biphenyl 2-hydroxylase. No correlation between the enhancement of biphenyl 2-hydroxylase and inhibtion of biphenyl 4-hydroxylase was apparent.
Topics: Acetone; Aniline Hydroxylase; Animals; Benzopyrene Hydroxylase; Benzopyrenes; Catechol Oxidase; Cricetinae; Cytochromes; Dactinomycin; Dioxoles; Male; Methylcholanthrene; Metyrapone; Mice; Microsomes, Liver; NADPH-Ferrihemoprotein Reductase; Nikethamide; Phenobarbital; Rats; Safrole
PubMed: 821473
DOI: 10.1042/bj1540773 -
Journal of Bacteriology Oct 1965Moore, B. G. (Oak Ridge National Laboratory, Oak Ridge, Tenn.), and Arthur P. Harrison, Jr. Benzo[a]pyrene uptake by bacteria and yeast. J. Bacteriol. 90:989-1000....
Moore, B. G. (Oak Ridge National Laboratory, Oak Ridge, Tenn.), and Arthur P. Harrison, Jr. Benzo[a]pyrene uptake by bacteria and yeast. J. Bacteriol. 90:989-1000. 1965.-Various Enterobacteriaceae and yeast incubated in a medium containing 25 mug/ml of H(3)-benzo[a]pyrene (30% serum in the medium dissolves the hydrocarbon) retain radioactivity after washings with fresh 30% serum-medium. This radioactivity is defined as bound and represents intact benzo[a]pyrene. Factors relating to the binding of benzo[a]pyrene (benzo[a]pyrene uptake) have been studied in detail with Escherichia coli Ma, a triple auxotroph requiring l-leucine, uracil, and thymine. In defined medium, benzo[a]pyrene uptake by normally growing cells is 10(-10) to 2 x 10(-10) mug per cell. Uptake is the same in suspensions lacking leucine and containing chloramphenicol where there is neither measurable protein synthesis nor cell division. Uptake is diminished, but not eliminated, by autoclaving the cells; thus, some uptake occurs in the absence of enzymatic activity. Uptake is enhanced by heat shock, thymine deprivation, uracil deprivation, and exposure to penicillin. Thus, uptake is affected by the physiological state of the cells. Either the cells play a direct (enzymatic) role in uptake, or they affect uptake indirectly by increasing or altering the benzo[a]pyrene-binding structure. Physical fractionation of cells demonstrates that this structure is associated with the cell wall-membrane complex. All but 1% of the bound radioactivity is extracted with ethyl alcohol-ether. This residual radioactivity is defined as fixed, and may be associated with cell protein. The extracted radioactivity is identified as benzo[a]pyrene. Very little hydrocarbon is metabolized. Adverse photodynamic effects, increase in mutation, and dimunition in bacteriophage replication (in whole cells) have not been observed in the benzo[a]pyrene cultures.
Topics: Benzopyrenes; Carbon Isotopes; Chromatography; Coliphages; Enterobacter; Escherichia coli; Glucose; Hot Temperature; In Vitro Techniques; Penicillins; Saccharomyces; Salmonella typhimurium; Thymine; Uracil
PubMed: 5321405
DOI: 10.1128/jb.90.4.989-1000.1965 -
Scientific Reports Jul 2020To reveal the impacts of smoking on genetic architecture of human body weight, we conducted a genome-wide association study on 5,336 subjects in four ethnic populations...
To reveal the impacts of smoking on genetic architecture of human body weight, we conducted a genome-wide association study on 5,336 subjects in four ethnic populations from MESA (The Multi-Ethnic Study of Atherosclerosis) data. A full genetic model was applied to association mapping for analyzing genetic effects of additive, dominance, epistasis, and their ethnicity-specific effects. Both the unconditional model (base) and conditional model including smoking as a cofactor were investigated. There were 10 SNPs involved in 96 significant genetic effects detected by the base model, which accounted for a high heritability (61.78%). Gene ontology analysis revealed that a number of genetic factors are related to the metabolic pathway of benzopyrene, a main compound in cigarettes. Smoking may play important roles in genetic effects of dominance, dominance-related epistasis, and gene-ethnicity interactions on human body weight. Gene effect prediction shows that the genetic effects of smoking cessation on body weight vary from different populations.
Topics: Atherosclerosis; Benzopyrenes; Body Weight; Epistasis, Genetic; Ethnicity; Gene Ontology; Genome-Wide Association Study; Genotype; Humans; Phenotype; Polymorphism, Single Nucleotide; Quantitative Trait, Heritable; Smoking
PubMed: 32699216
DOI: 10.1038/s41598-020-68935-x -
Cells Jul 2020Resistance of cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis represents the major hurdle to the clinical use of TRAIL...
Resistance of cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis represents the major hurdle to the clinical use of TRAIL or its derivatives. The discovery and development of lead compounds able to sensitize tumor cells to TRAIL-induced cell death is thus likely to overcome this limitation. We recently reported that marine actinomycetes' crude extracts could restore TRAIL sensitivity of the MDA-MB-231 resistant triple negative breast cancer cell line. We demonstrate in this study, that purified secondary metabolites originating from distinct marine actinomycetes (sharkquinone (1), resistomycin (2), undecylprodigiosin (3), butylcyclopentylprodigiosin (4), elloxizanone A (5) and B (6), carboxyexfoliazone (7), and exfoliazone (8)), alone, and in a concentration-dependent manner, induce killing in both MDA-MB-231 and HCT116 cell lines. Combined with TRAIL, these compounds displayed additive to synergistic apoptotic activity in the Jurkat, HCT116 and MDA-MB-231 cell lines. Mechanistically, these secondary metabolites induced and enhanced procaspase-10, -8, -9 and -3 activation leading to an increase in PARP and lamin A/C cleavage. Apoptosis induced by these compounds was blocked by the pan-caspase inhibitor QvD, but not by a deficiency in caspase-8, FADD or TRAIL agonist receptors. Activation of the intrinsic pathway, on the other hand, is likely to explain both their ability to trigger cell death and to restore sensitivity to TRAIL, as it was evidenced that these compounds could induce the downregulation of XIAP and survivin. Our data further highlight that compounds derived from marine sources may lead to novel anti-cancer drug discovery.
Topics: Actinobacteria; Apoptosis; Aquatic Organisms; Benzopyrenes; Caspase 8; Cell Survival; Down-Regulation; Drug Discovery; Drug Resistance, Neoplasm; Gene Deletion; HCT116 Cells; Humans; Jurkat Cells; Oxazines; Prodigiosin; Quinones; Secondary Metabolism; Survivin; TNF-Related Apoptosis-Inducing Ligand; X-Linked Inhibitor of Apoptosis Protein
PubMed: 32708048
DOI: 10.3390/cells9081760 -
Toxicology and Applied Pharmacology Dec 2011Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants generated as byproducts of natural and anthropogenic combustion processes. Despite...
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants generated as byproducts of natural and anthropogenic combustion processes. Despite significant public health concern, physiologically based pharmacokinetic (PBPK) modeling efforts for PAHs have so far been limited to naphthalene, plus simpler PK models for pyrene, nitropyrene, and benzo[a]pyrene (B[a]P). The dearth of published models is due in part to the high lipophilicity, low volatility, and myriad metabolic pathways for PAHs, all of which present analytical and experimental challenges. Our research efforts have focused upon experimental approaches and initial development of PBPK models for the prototypic PAH, B[a]P, and the more potent, albeit less studied transplacental carcinogen, dibenzo[def,p]chrysene (DBC). For both compounds, model compartments included arterial and venous blood, flow limited lung, liver, richly perfused and poorly perfused tissues, diffusion limited fat, and a two compartment theoretical gut (for oral exposures). Hepatic and pulmonary metabolism was described for both compounds, as were fractional binding in blood and fecal clearance. Partition coefficients for parent PAH along with their diol and tetraol metabolites were estimated using published algorithms and verified experimentally for the hydroxylated metabolites. The preliminary PBPK models were able to describe many, but not all, of the available data sets, comprising multiple routes of exposure (oral, intravenous) and nominal doses spanning several orders of magnitude.
Topics: Administration, Oral; Algorithms; Animals; Benzo(a)pyrene; Benzopyrenes; Environmental Pollutants; Female; Injections, Intravenous; Mice; Models, Biological; Rats; Rats, Sprague-Dawley; Tissue Distribution
PubMed: 22001385
DOI: 10.1016/j.taap.2011.09.020 -
International Journal of Environmental... Jun 2007Polycyclic aromatic hydrocarbons (PAHs) are widespread genotoxic environmental pollutants and potentially pose a health risk to humans. Although the biological and...
Polycyclic aromatic hydrocarbons (PAHs) are widespread genotoxic environmental pollutants and potentially pose a health risk to humans. Although the biological and toxicological activities, including metabolism, mutagenicity and carcinogenicity of PAHs have been thoroughly studied, their phototoxicity and photo-induced biological activities have not been well examined. In this research, we studied the photoirradiation of isomeric methylbenzo[a]pyrene (MBaP) and methylbenzo[e]pyrene (MBeP) by UVA light in the presence of a lipid, methyl linoleate, and evaluated the potential of these compounds to induce lipid peroxidation. The compounds chosen for study included BaP, 3-MBaP, 4-MBaP, 6-MBaP, 7-MBaP, 10-MBaP, BeP, 4-MBeP, and 9-MBeP. The results indicate that upon photoirradiation by UVA at 7 and 21 J/cm2, these compounds induced lipid peroxidation. The levels of the induced lipid peroxidation were similar among BaP and the isomeric MBaPs, and among the BeP and MBePs, with the BaP group higher than the BeP group. There was also a co-relation between the UV A light dose and the level of lipid peroxidation induced. Lipid peroxide formation was inhibited by NaN3 (singlet oxygen and free radical scavenger) and was enhanced by the presence of deuterium oxide (D2O) (extends singlet oxygen lifetime). These results suggest that photoirradiation of MBaPs and MBePs by UVA light generates reactive oxygen species (ROS), which induce lipid peroxidation.
Topics: Benzo(a)pyrene; Benzopyrenes; Free Radical Scavengers; Humans; Lipid Peroxidation; Lipid Peroxides; Phototherapy; Polycyclic Aromatic Hydrocarbons; Pyrenes; Reactive Oxygen Species; Singlet Oxygen; Superoxides; Ultraviolet Rays
PubMed: 17617679
DOI: 10.3390/ijerph2007040010 -
Applied and Environmental Microbiology Jan 2004Metabolism of the environmental pollutant benzo[a]pyrene in the bacterium Mycobacterium vanbaalenii PYR-1 was examined. This organism initially oxidized benzo[a]pyrene...
Metabolism of the environmental pollutant benzo[a]pyrene in the bacterium Mycobacterium vanbaalenii PYR-1 was examined. This organism initially oxidized benzo[a]pyrene with dioxygenases and monooxygenases at C-4,5, C-9,10, and C-11,12. The metabolites were separated by reversed-phase high-performance liquid chromatography (HPLC) and characterized by UV-visible, mass, nuclear magnetic resonance, and circular dichroism spectral analyses. The major intermediates of benzo[a]pyrene metabolism that had accumulated in the culture media after 96 h of incubation were cis-4,5-dihydro-4,5-dihydroxybenzo[a]pyrene (benzo[a]pyrene cis-4,5-dihydrodiol), cis-11,12-dihydro-11,12-dihydroxybenzo[a]pyrene (benzo[a]pyrene cis-11,12-dihydrodiol), trans-11,12-dihydro-11,12-dihydroxybenzo[a]pyrene (benzo[a]pyrene trans-11,12-dihydrodiol), 10-oxabenzo[def]chrysen-9-one, and hydroxymethoxy and dimethoxy derivatives of benzo[a]pyrene. The ortho-ring fission products 4-formylchrysene-5-carboxylic acid and 4,5-chrysene-dicarboxylic acid and a monocarboxylated chrysene product were formed when replacement culture experiments were conducted with benzo[a]pyrene cis-4,5-dihydrodiol. Chiral stationary-phase HPLC analysis of the dihydrodiols indicated that benzo[a]pyrene cis-4,5-dihydrodiol had 30% 4S,5R and 70% 4R,5S absolute stereochemistry. Benzo[a]pyrene cis-11,12-dihydrodiol adopted an 11S,12R conformation with 100% optical purity. The enantiomeric composition of benzo[a]pyrene trans-11,12-dihydrodiol was an equal mixture of 11S,12S and 11R,12R molecules. The results of this study, in conjunction with those of previously reported studies, extend the pathways proposed for the bacterial metabolism of benzo[a]pyrene. Our study also provides evidence of the stereo- and regioselectivity of the oxygenases that catalyze the metabolism of benzo[a]pyrene in M. vanbaalenii PYR-1.
Topics: Benzopyrenes; Biodegradation, Environmental; Chromatography, High Pressure Liquid; Circular Dichroism; Environmental Pollutants; Magnetic Resonance Spectroscopy; Mass Spectrometry; Mycobacterium; Stereoisomerism
PubMed: 14711661
DOI: 10.1128/AEM.70.1.340-345.2004