Publications by authors named "Steen Mollerup"

28 Publications

  • Page 1 of 1

Biological effects of combustion-derived particles from different biomass sources on human bronchial epithelial cells.

Toxicol In Vitro 2021 May 5;75:105190. Epub 2021 May 5.

Section of Pollution and Noise, Department of Environmental Health, Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403 Oslo, Norway. Electronic address:

Combustion-derived particles (CDPs), in particular from traffic, are regarded as a central contributor for adverse health effects linked to air pollution. Recently, also biomass burning has been recognized as an important source for CDPs. Here, the effects of CDPs (PM) originating from burning of pellet, charcoal and wood on key processes associated to lung carcinogenesis were explored. Human bronchial epithelial cells (HBEC3-KT) were exposed to 2.5 μg/cm of CDPs for 24 h and biological effects were examined in terms of cytotoxicity, inflammation, epithelial to mesenchymal transition (EMT)-related effects, DNA damage and genotoxicity. Reduced cell migration, inflammation and modulation of various PM-associated genes were observed mainly after exposure to wood and pellet. In contrast, only particles from pellet burning induced alteration in cell proliferation and DNA damage, which resulted in cell cycle alterations. Charcoal instead, appeared in general less effective in inducing pro-carcinogenic effects. These results illustrate differences in the toxicological profile due to the CDPs source. The different chemical compounds adsorbed on CDPs seemed to be central for particle properties, leading to an activation of various cellular signaling pathways involved in early steps of cancer progression.
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http://dx.doi.org/10.1016/j.tiv.2021.105190DOI Listing
May 2021

The airborne mycobiome and associations with mycotoxins and inflammatory markers in the Norwegian grain industry.

Sci Rep 2021 Apr 30;11(1):9357. Epub 2021 Apr 30.

Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.

Grain dust exposure is associated with respiratory symptoms among grain industry workers. However, the fungal assemblage that contribute to airborne grain dust has been poorly studied. We characterized the airborne fungal diversity at industrial grain- and animal feed mills, and identified differences in diversity, taxonomic compositions and community structural patterns between seasons and climatic zones. The fungal communities displayed strong variation between seasons and climatic zones, with 46% and 21% of OTUs shared between different seasons and climatic zones, respectively. The highest species richness was observed in the humid continental climate of the southeastern Norway, followed by the continental subarctic climate of the eastern inland with dryer, short summers and snowy winters, and the central coastal Norway with short growth season and lower temperature. The richness did not vary between seasons. The fungal diversity correlated with some specific mycotoxins in settled dust and with fibrinogen in the blood of exposed workers, but not with the personal exposure measurements of dust, glucans or spore counts. The study contributes to a better understanding of fungal exposures in the grain and animal feed industry. The differences in diversity suggest that the potential health effects of fungal inhalation may also be different.
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http://dx.doi.org/10.1038/s41598-021-88252-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8087811PMC
April 2021

Circulating miRNAs as molecular markers of occupational grain dust exposure.

Sci Rep 2020 07 9;10(1):11317. Epub 2020 Jul 9.

National Institute of Occupational Health, Gydas vei 8, PO Box 5330, 0304, Majorstuen, Oslo, Norway.

Dust from grain and feed production may cause adverse health effects in exposed workers. In this study we explored circulating miRNAs as potential biomarkers of occupational grain dust exposure. Twenty-two serum miRNAs were analyzed in 44 grain dust exposed workers and 22 controls. Exposed workers had significantly upregulated miR-18a-5p, miR-124-3p and miR-574-3p, and downregulated miR-19b-3p and miR-146a-5p, compared to controls. Putative target genes for the differentially expressed miRNAs were involved in a range of Kyoto Encyclopedia of Genes and Genomes signaling pathways, and 'Pathways in cancer' and 'Wnt signaling pathway' were common for all the five miRNAs. MiRNA-diseases association analysis showed a link between the five identified miRNAs and several lung diseases terms. A positive correlation between miR-124-3p, miR-18a-5p, and miR-574-3p and IL-6 protein level was shown, while miR-19b-3p was inversely correlated with CC-16 and sCD40L protein levels. Receiver-operating characteristic analysis of the five miRNA showed that three miRNAs (miR-574-3p, miR-124-3p and miR-18a-5p) could distinguish the grain dust exposed group from the control group, with miR-574-3p as the strongest predictor of grain dust exposure. In conclusion, this study identified five signature miRNAs as potential novel biomarkers of grain dust exposure that may have potential as early disease markers.
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http://dx.doi.org/10.1038/s41598-020-68296-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7347934PMC
July 2020

The Inhalable Mycobiome of Sawmill Workers: Exposure Characterization and Diversity.

Appl Environ Microbiol 2019 11 16;85(21). Epub 2019 Oct 16.

Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.

Exposure to fungal spores has been associated with respiratory symptoms and allergic alveolitis among sawmill workers, but the complexity of sawmill workers' fungal exposure has been poorly studied. We characterized the fungal diversity in air samples from sawmill workers' breathing zones and identified differences in the richness, diversity, and taxonomic composition between companies, departments, wood types, and seasons. Full-shift personal inhalable dust samples ( = 86) collected from 11 industrial sawmill, sorting mill, and planer mill companies processing spruce and/or pine were subjected to DNA metabarcoding using the fungal internal transcribed spacer (ITS) region 2. The workers were exposed to a higher total number of operational taxonomic units (OTUs) in summer than in winter and when processing spruce than when processing pine. Workers in the saw department had the richest fungal exposure, followed by workers in the planing department and sorting of dry timber department. Sawmills explained 11% of the variation in the fungal community composition of the exposure, followed by season (5%) and department (3%). The fungal compositions of the exposures also differed between seasons, sawmills, wood types, and departments at the taxonomic level, ranging from the phylum to the species level. The differences in exposure diversity suggest that the potential health effects of fungal inhalation may also be different; hence, a risk assessment based on the fungal diversity differences should be performed. This study may serve as a basis for establishing a fungal profile of signature species that are specific for sawmills and that can be measured quantitatively in future risk assessments of sawmill workers. To gain more knowledge about exposure-response relationships, it is important to improve exposure characterization by comprehensively identifying the temporal and spatial fungal composition and diversity of inhalable dust at workplaces. The variation in the diverse fungal communities to which individuals are exposed in different seasons and sawmills suggests that variations in exposure-related health effects between seasons and companies can be expected. More importantly, the distinct fungal profiles between departments across companies indicate that workers in different job groups are differently exposed and that health risks can be department specific. DNA metabarcoding provides insight into a broad spectrum of airborne fungi that may serve as a basis for obtaining important knowledge about the fungi to which workers are exposed.
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http://dx.doi.org/10.1128/AEM.01448-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6803317PMC
November 2019

Bulky DNA adducts, microRNA profiles, and lipid biomarkers in Norwegian tunnel finishing workers occupationally exposed to diesel exhaust.

Occup Environ Med 2019 01 13;76(1):10-16. Epub 2018 Nov 13.

Section for Toxicology and Biological Work Environment, Department of Chemical and Biological Work Environment, National Institute of Occupational Health, Oslo, Norway.

Objectives: This study aimed to assess the biological impact of occupational exposure to diesel exhaust (DE) including DE particles (DEP) from heavy-duty diesel-powered equipment in Norwegian tunnel finishing workers (TFW).

Methods: TFW (n=69) and referents (n=69) were investigated for bulky DNA adducts (by P-postlabelling) and expression of microRNAs (miRNAs) (by small RNA sequencing) in peripheral blood mononuclear cells (PBMC), as well as circulating free arachidonic acid (AA) and eicosanoid profiles in plasma (by liquid chromatography-tandem mass spectrometry).

Results: PBMC from TFW showed significantly higher levels of DNA adducts compared with referents. Levels of DNA adducts were also related to smoking habits. Seventeen miRNAs were significantly deregulated in TFW. Several of these miRNAs are related to carcinogenesis, apoptosis and antioxidant effects. Analysis of putative miRNA-gene targets revealed deregulation of pathways associated with cancer, alterations in lipid molecules, steroid biosynthesis and cell cycle. Plasma profiles showed higher levels of free AA and 15-hydroxyeicosatetraenoic acid, and lower levels of prostaglandin D and 9-hydroxyoctadecadienoic acid in TFW compared with referents.

Conclusion: Occupational exposure to DE/DEP is associated with biological alterations in TFW potentially affecting lung homoeostasis, carcinogenesis, inflammation status and the cardiovascular system. Of particular importance is the finding that tunnel finishing work is associated with an increased level of DNA adducts formation in PBMC.
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http://dx.doi.org/10.1136/oemed-2018-105445DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327869PMC
January 2019

In Vitro Transformation of Human Bronchial Epithelial Cells by Diesel Exhaust Particles: Gene Expression Profiling and Early Toxic Responses.

Toxicol Sci 2018 11;166(1):51-64

Section for Toxicology and Biological Work Environment, Department of Chemical and Biological Work Environment, National Institute of Occupational Health, N-0304 Oslo, Norway.

Occupational exposure to diesel exhaust may cause lung cancer in humans. Mechanisms include DNA-damage and inflammatory responses. Here, the potential of NIST SRM2975 diesel exhaust particles (DEP) to transform human bronchial epithelial cells (HBEC3) in vitro was investigated. Long-term exposure of HBEC3 to DEP led to increased colony growth in soft agar. Several DEP-transformed cell lines were established and based on the expression of epithelial-to-mesenchymal-transition (EMT) marker genes, one of them (T2-HBEC3) was further characterized. T2-HBEC3 showed a mesenchymal/fibroblast-like morphology, reduced expression of CDH1, and induction of CDH2 and VIM. T2-HBEC3 had reduced migration potential compared with HBEC3 and little invasion capacity. Gene expression profiling showed baseline differences between HBEC3 and T2-HBEC3 linked to lung carcinogenesis. Next, to assess differences in sensitivity to DEP between parental HBEC3 and T2-HBEC3, gene expression profiling was carried out after DEP short-term exposure. Results revealed changes in genes involved in metabolism of xenobiotics and lipids, as well as inflammation. HBEC3 displayed a higher steady state of IL1B gene expression and release of IL-1β compared with T2-HBEC3. HBEC3 and T2-HBEC3 showed similar susceptibility towards DEP-induced genotoxic effects. Liquid-chromatography-tandem-mass-spectrometry was used to measure secretion of eicosanoids. Generally, major prostaglandin species were released in higher concentrations from T2-HBEC3 than from HBEC3 and several analytes were altered after DEP-exposure. In conclusion, long-term exposure to DEP-transformed human bronchial epithelial cells in vitro. Differences between HBEC3 and T2-HBEC3 regarding baseline levels and DEP-induced changes of particularly CYP1A1, IL-1β, PGE2, and PGF2α may have implications for acute inflammation and carcinogenesis.
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http://dx.doi.org/10.1093/toxsci/kfy183DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6204768PMC
November 2018

The role of SerpinB2 in human bronchial epithelial cells responses to particulate matter exposure.

Arch Toxicol 2018 09 9;92(9):2923-2933. Epub 2018 Jul 9.

Department of Biological and Chemical Working Environment, National Institute of Occupational Health, 0033, Oslo, Norway.

Exposure to particulate matter (PM) has been related to the onset of adverse health effects including lung cancer, but the underlying molecular mechanisms are still under investigation. Epithelial-to-mesenchymal transition (EMT) is regarded as a crucial step in cancer progression. In a previous study, we reported EMT-related responses in the human bronchial epithelial cell line HBEC3-KT, exposed to Milan airborne winter PM2.5. We also found a strong modulation of SERPINB2, encoding for the PAI-2 protein and previously suggested to play an important role in cancer. Here we investigate the role of SERPINB2/PAI-2 in the regulation of EMT-related effects induced by PM exposure in HBEC3-KT. PM exposure (up to 10 µg/cm) increased SERPINB2 expression, reduced cell migration and induced morphological alterations in HBEC3-KT. Changes in actin structure and cadherin-1 relocalization were observed in PM-exposed samples. Knockdown of SERPINB2 by siRNA down-regulated the CDH1 gene expression, as well as PAI-2 and cadherin-1 protein expression. SERPINB2 knockdown also increased cell migration rate, and counteracted the PM-induced reduction of cell migration and alteration of cell morphology. SERPINB2 was found to be greatly down-regulated in a HBEC2-KT transformed cell line, supporting the importance of this gene in the regulation of EMT. In conclusion, here we show that PAI-2 regulates CDH1 gene/cadherin-1 protein expression in bronchial HBEC3-KT cells, and this mechanism might be involved in the regulation of cell migration. SERPINB2 down-regulation should be considered part of EMT, and the over-expression of SERPINB2 in PM-exposed samples might be interpreted as an initial protective mechanism.
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http://dx.doi.org/10.1007/s00204-018-2259-zDOI Listing
September 2018

A Two-Gene Prognostic Classifier for Early-Stage Lung Squamous Cell Carcinoma in Multiple Large-Scale and Geographically Diverse Cohorts.

J Thorac Oncol 2017 01 6;12(1):65-76. Epub 2016 Sep 6.

Laboratory of Human Carcinogenesis, National Cancer Institute Center for Cancer Research, National Institutes of Health, Bethesda, Maryland. Electronic address:

Introduction: There are no validated molecular methods that prospectively identify patients with surgically resected lung squamous cell carcinoma (SCC) at high risk for recurrence. By focusing on the expression of genes with known functions in development of lung SCC and prognosis, we sought to develop a robust prognostic classifier of early-stage lung SCC.

Methods: The expression of 253 genes selected by literature search was evaluated in microarrays from 107 stage I/II tumors. Associations with survival were evaluated by Cox regression and Kaplan-Meier survival analyses in two independent cohorts of 121 and 91 patients with SCC, respectively. A classifier score based on multivariable Cox regression was derived and examined in six additional publicly available data sets of stage I/II lung SCC expression profiles (n = 358). The prognostic value of this classifier was evaluated in meta-analysis of patients with stage I/II (n = 479) and stage I (n = 326) lung SCC.

Results: Dual specificity phosphatase 6 gene (DUSP6) and actinin alpha 4 gene (ACTN4) were associated with prognostic outcome in two independent patient cohorts. Their expression values were utilized to develop a classifier that identified patients with stage I/II lung SCC at high risk for recurrence (hazard ratio [HR] = 4.7, p = 0.018) or cancer-specific mortality (HR = 3.5, p = 0.016). This classifier also identified patients at high risk for recurrence (HR = 2.7, p = 0.008) or death (HR = 2.2, p = 0.001) in publicly available data sets of stage I/II and in meta-analysis of stage I patients.

Conclusions: We have established and validated a prognostic classifier to inform clinical management of patients with lung SCC after surgical resection.
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http://dx.doi.org/10.1016/j.jtho.2016.08.141DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6503970PMC
January 2017

Estrogen receptor expression and gene promoter methylation in non-small cell lung cancer - a short report.

Cell Oncol (Dordr) 2016 Dec 29;39(6):583-589. Epub 2016 Aug 29.

Section for Toxicology and Biological Working Environment, Department of Biological and Chemical Working Environment, National Institute of Occupational Health, PO box 8149, Dep., Gydas vei 8, N-0033, Oslo, Norway.

Purpose: In the past, anomalous estrogen receptor (ER) regulation has been associated with various lung pathologies, but so far its involvement in lung cancer initiation and/or progression has remained unclear. Here, we aimed at assessing in vivo and in vitro ER expression and its possible epigenetic regulation in non-small cell lung cancer (NSCLC) samples and their corresponding normal tissues and cells.

Methods: ERα and ERβ gene expression levels were assessed using real time quantitative PCR (RT-qPCR), whereas ERα and ERβ gene promoter methylation levels were assessed using DNA bisulfite conversion followed by pyrosequencing. We included NSCLC (n = 87) and adjacent histologically normal lung tissue samples from lung cancer patients (n = 184), primary normal bronchial epithelial-derived cell cultures (n = 11), immortalized bronchial epithelial-derived cell lines (n = 3) and NSCLC derived cell lines (n = 9).

Results: Using RT-qPCR we found significantly lower ERα and ERβ expression levels in the NSCLC tissue samples compared to their normal adjacent tissue samples. These lower ER expression levels were confirmed in vitro using primary normal bronchial epithelial-derived cell cultures, immortalized bronchial epithelial-derived cell lines and NSCLC-derived cell lines. By using this latter panel of cells, we found that ER gene promoter hypermethylation was associated with decreased ER expression. In addition we found that in tumor and normal lung tissues, smoking was associated with decreased ER expression and that normal lung tissues with a low ERβ expression level exhibited increased smoking-related DNA adducts.

Conclusions: Taken together, our results indicate that decreased ER expression mediated by DNA methylation may play a role in NSCLC development.
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http://dx.doi.org/10.1007/s13402-016-0295-3DOI Listing
December 2016

Epithelial-mesenchymal transition and FOXA genes during tobacco smoke carcinogen induced transformation of human bronchial epithelial cells.

Toxicol In Vitro 2016 Sep 21;35:55-65. Epub 2016 May 21.

Section for Toxicology and Biological Working Environment, Department of Biological and Chemical Working Environment, National Institute of Occupational Health, N-0033 Oslo, Norway. Electronic address:

Lung cancer is largely an environmentally caused disease with poor prognosis. An in vitro transformation model of human bronchial epithelial cells (HBEC) was used to study long-term effects of tobacco smoke carcinogens on epithelial-mesenchymal transition (EMT) and the forkhead box transcription factors FOXA1 and FOXA2. CDK4 and hTERT immortalized HBEC2 and HBEC12 cell lines were exposed weekly to either cigarette smoke condensate (CSC), benzo[a]pyrene, or methylnitrosourea. Transformed cell lines were established from soft-agar colonies after 12weeks of exposure. HBEC12 was transformed by all exposures while HBEC2 was only transformed by CSC. Untransformed HBEC2 showed little invasive capacity, whereas transformed cell lines completely closed the gap in a matrigel scratch wound assay. CDH1 was down-regulated in all of the transformed cell lines. In contrast, CDH2 was up-regulated in both HBEC2 and one of the HBEC12 transformed cell lines. Furthermore, transformed cells showed activation of EMT markers including SNAI1, ZEB1, VIM, and MMP2. All transformed cell lines had significant down-regulation of FOXA1 and FOXA2, indicating a possible role in cell transformation and EMT. ChIP analysis showed increased binding of Histone-H3 and macroH2A in FOXA1 and FOXA2 in the transformed HBEC2 cell lines, indicating a compact chromatin. In conclusion, long-term carcinogen exposure lead to down-regulation of FOXA1 and FOXA2 concomitantly with the occurrence of EMT and in vitro transformation in HBEC cells.
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http://dx.doi.org/10.1016/j.tiv.2016.04.012DOI Listing
September 2016

Physico-chemical properties and biological effects of diesel and biomass particles.

Environ Pollut 2016 Aug 15;215:366-375. Epub 2016 May 15.

Polaris Research Centre, Dept. of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza, 1, 20126, Milan, Italy.

Diesel combustion and solid biomass burning are the major sources of ultrafine particles (UFP) in urbanized areas. Cardiovascular and pulmonary diseases, including lung cancer, are possible outcomes of combustion particles exposure, but differences in particles properties seem to influence their biological effects. Here the physico-chemical properties and biological effects of diesel and biomass particles, produced under controlled laboratory conditions, have been characterized. Diesel UFP were sampled from a Euro 4 light duty vehicle without DPF fuelled by commercial diesel and run over a chassis dyno. Biomass UFP were collected from a modern automatic 25 kW boiler propelled by prime quality spruce pellet. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of both diesel and biomass samples showed aggregates of soot particles, but in biomass samples ash particles were also present. Chemical characterization showed that metals and PAHs total content was higher in diesel samples compared to biomass ones. Human bronchial epithelial (HBEC3) cells were exposed to particles for up to 2 weeks. Changes in the expression of genes involved in xenobiotic metabolism were observed after exposure to both UFP already after 24 h. However, only diesel particles modulated the expression of genes involved in inflammation, oxidative stress and epithelial-to-mesenchymal transition (EMT), increased the release of inflammatory mediators and caused phenotypical alterations, mostly after two weeks of exposure. These results show that diesel UFP affected cellular processes involved in lung and cardiovascular diseases and cancer. Biomass particles exerted low biological activity compared to diesel UFP. This evidence emphasizes that the study of different emission sources contribution to ambient PM toxicity may have a fundamental role in the development of more effective strategies for air quality improvement.
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http://dx.doi.org/10.1016/j.envpol.2016.05.015DOI Listing
August 2016

An Integrated Prognostic Classifier for Stage I Lung Adenocarcinoma Based on mRNA, microRNA, and DNA Methylation Biomarkers.

J Thorac Oncol 2015 Jul;10(7):1037-48

*Laboratory of Human Carcinogenesis, NCI-CCR, National Institutes of Health, Bethesda, Maryland; †Division of Molecular Pathology, National Cancer Center Research Institute, Tokyo, Japan; ‡Genetics Branch, NCI-CCR, National Institutes of Health, Bethesda, Maryland; §Division of Genome Biology, National Cancer Center Research Institute, Tokyo, Japan; ‖Department of Chemical and Biological Working Environment, National Institute of Occupational Health, Oslo, Norway; and ¶Genomics and Epigenomics of Cancer Prediction Program, Institute of Predictive and Personalized Medicine of Cancer (IMPPC), Badalona (Barcelona), Spain.

Introduction: Up to 30% stage I lung cancer patients suffer recurrence within 5 years of curative surgery. We sought to improve existing protein-coding gene and microRNA expression prognostic classifiers by incorporating epigenetic biomarkers.

Methods: Genome-wide screening of DNA methylation and pyrosequencing analysis of HOXA9 promoter methylation were performed in two independently collected cohorts of stage I lung adenocarcinoma. The prognostic value of HOXA9 promoter methylation alone and in combination with mRNA and miRNA biomarkers was assessed by Cox regression and Kaplan-Meier survival analysis in both cohorts.

Results: Promoters of genes marked by polycomb in embryonic stem cells were methylated de novo in tumors and identified patients with poor prognosis. The HOXA9 locus was methylated de novo in stage I tumors (p < 0.0005). High HOXA9 promoter methylation was associated with worse cancer-specific survival (hazard ratio [HR], 2.6; p = 0.02) and recurrence-free survival (HR, 3.0; p = 0.01), and identified high-risk patients in stratified analysis of stages IA and IB. Four protein-coding gene (XPO1, BRCA1, HIF1α, and DLC1), miR-21 expression, and HOXA9 promoter methylation were each independently associated with outcome (HR, 2.8; p = 0.002; HR, 2.3; p = 0.01; and HR, 2.4; p = 0.005, respectively), and when combined, identified high-risk, therapy naive, stage I patients (HR, 10.2; p = 3 × 10). All associations were confirmed in two independently collected cohorts.

Conclusion: A prognostic classifier comprising three types of genomic and epigenomic data may help guide the postoperative management of stage I lung cancer patients at high risk of recurrence.
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http://dx.doi.org/10.1097/JTO.0000000000000560DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4493931PMC
July 2015

Protective action of n-3 fatty acids on benzo[a]pyrene-induced apoptosis through the plasma membrane remodeling-dependent NHE1 pathway.

Chem Biol Interact 2014 Jan 15;207:41-51. Epub 2013 Nov 15.

Inserm U1085, Institut de Recherche en Santé, Environnement, Travail, Rennes, France; Université de Rennes 1, SFR Biosit, Rennes, France. Electronic address:

Plasma membrane is an early target of polycyclic aromatic hydrocarbons (PAH). We previously showed that the PAH prototype, benzo[a]pyrene (B[a]P), triggers apoptosis via DNA damage-induced p53 activation (genotoxic pathway) and via remodeling of the membrane cholesterol-rich microdomains called lipid rafts, leading to changes in pH homeostasis (non-genotoxic pathway). As omega-3 (n-3) fatty acids can affect membrane composition and function or hamper in vivo PAH genotoxicity, we hypothesized that addition of physiologically relevant levels of polyunsaturated n-3 fatty acids (PUFAs) might interfere with B[a]P-induced toxicity. The effects of two major PUFAs, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), were tested on B[a]P cytotoxicity in the liver epithelial cell line F258. Both PUFAs reduced B[a]P-induced apoptosis. Surprisingly, pre-treatment with DHA increased the formation of reactive B[a]P metabolites, resulting in higher levels of B[a]P-DNA adducts. EPA had no apparent effect on B[a]P metabolism or related DNA damage. EPA and DHA prevented B[a]P-induced apoptotic alkalinization by affecting Na(+)/H(+) exchanger 1 activity. Thus, the inhibitory effects of omega-3 fatty acids on B[a]P-induced apoptosis involve a non-genotoxic pathway associated with plasma membrane remodeling. Our results suggest that dietary omega-3 fatty acids may have marked effects on the biological consequences of PAH exposure.
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http://dx.doi.org/10.1016/j.cbi.2013.11.002DOI Listing
January 2014

Combination of protein coding and noncoding gene expression as a robust prognostic classifier in stage I lung adenocarcinoma.

Cancer Res 2013 Jul 2;73(13):3821-32. Epub 2013 May 2.

Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892, USA.

Prognostic tests for patients with early-stage lung cancer may provide needed guidance on postoperative surveillance and therapeutic decisions. We used a novel strategy to develop and validate a prognostic classifier for early-stage lung cancer. Specifically, we focused on 42 genes with roles in lung cancer or cancer prognosis. Expression of these biologically relevant genes and their association with relapse-free survival (RFS) were evaluated using microarray data from 148 patients with stage I lung adenocarcinoma. Seven genes associated with RFS were further examined by quantitative reverse transcription PCR in 291 lung adenocarcinoma tissues from Japan, the United States, and Norway. Only BRCA1, HIF1A, DLC1, and XPO1 were each significantly associated with prognosis in the Japan and US/Norway cohorts. A Cox regression-based classifier was developed using these four genes on the Japan cohort and validated in stage I lung adenocarcinoma from the US/Norway cohort and three publicly available lung adenocarcinoma expression profiling datasets. The results suggest that the classifier is robust across ethnically and geographically diverse populations regardless of the technology used to measure gene expression. We evaluated the combination of the four-gene classifier with miRNA miR-21 (MIR21) expression and found that the combination improved associations with prognosis, which were significant in stratified analyses on stage IA and stage IB patients. Thus, the four coding gene classifier, alone or with miR-21 expression, may provide a clinically useful tool to identify high-risk patients and guide recommendations regarding adjuvant therapy and postoperative surveillance of patients with stage I lung adenocarcinoma.
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http://dx.doi.org/10.1158/0008-5472.CAN-13-0031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6503978PMC
July 2013

DNA methylation of the CYP1A1 enhancer is associated with smoking-induced genetic alterations in human lung.

Int J Cancer 2012 Oct 28;131(7):1509-16. Epub 2012 Feb 28.

Section for Toxicology, Department of Biological and Chemical Working Environment, National Institute of Occupational Health, Oslo, Norway.

CYP1A1 (cytochrome P4501A1) catalyze the conversion of polycyclic aromatic hydrocarbons into reactive metabolites, which may induce DNA damage. We hypothesized that DNA methylation of the CYP1A1 enhancer could be involved in inter-individual differences in mRNA levels of CYP1A1 or affect the smoking-induced DNA damage in human lung. Using DNA bisulfite conversion and pyrosequencing, we show that DNA methylation of the CYP1A1 enhancer is affected by smoking. In adjacent histologically normal lung from lung cancer patients (n = 120), low levels of DNA methylation of the CYP1A1 enhancer were related to high levels of smoking-induced hydrophobic DNA adduct (p < 0.03), and to the presence of TP53 or K-ras mutations in the corresponding lung tumors (p < 0.03). We found an inverse correlation between DNA methylation of the CYP1A1 enhancer and mRNA levels in vivo (Spearman r = -0.54; p < 0.0001). Thus, in lung tumor tissues, the CYP1A1 enhancer hypermethylation was associated with lower mRNA levels compared to adjacent histologically normal tissue (p < 0.0001). In vitro, using a panel of cultured human lung cells, we found hypermethylation of the CYP1A1 enhancer in cancer cell lines and an inverse correlation between DNA methylation and mRNA levels (Spearman r = -0.53; p = 0.003). Altogether, our results indicated that low levels of DNA methylation of the CYP1A1 enhancer in histologically normal human lung were associated with high CYP1A1 mRNA levels and with smoking-induced genetic alterations; thus, it may play a role in the initiation of lung carcinogenesis.
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http://dx.doi.org/10.1002/ijc.27421DOI Listing
October 2012

Airborne urban particles (Milan winter-PM2.5) cause mitotic arrest and cell death: Effects on DNA, mitochondria, AhR binding and spindle organization.

Mutat Res 2011 Aug 30;713(1-2):18-31. Epub 2011 May 30.

Applied Cell Biology and Particles Effects, Department of Environmental Science, University Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy.

Airborne particulate matter (PM) is considered to be an important contributor to lung diseases. In the present study we report that Milan winter-PM2.5 inhibited proliferation in human bronchial epithelial cells (BEAS-2B) by inducing mitotic arrest. The cell cycle arrest was followed by an increase in mitotic-apoptotic cells, mitotic slippage and finally an increase in "classical" apoptotic cells. Exposure to winter-PM10 induced only a slight effect which may be due to the presence of PM2.5 in this fraction while pure combustion particles failed to disturb mitosis. Fewer cells expressing the mitosis marker phospho-histone H3 compared to cells with condensed chromosomes, suggest that PM2.5 induced premature mitosis. PM2.5 was internalized into the cells and often localized in laminar organelles, although particles without apparent plasma membrane covering were also seen. In PM-containing cells mitochondria and lysosomes were often damaged, and in mitotic cells fragmented chromosomes often appeared. PM2.5 induced DNA strands breaks and triggered a DNA-damage response characterized by increased phosphorylation of ATM, Chk2 and H2AX; as well as induced a marked increase in expression of the aryl hydrocarbon receptor (AhR)-regulated genes, CYP1A1, CYP1B1 and AhRR. Furthermore, some disturbance of the organization of microtubules was indicated. It is hypothesized that the induced mitotic arrest and following cell death was due to a premature chromosome condensation caused by a combination of DNA, mitochondrial and spindle damage.
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http://dx.doi.org/10.1016/j.mrfmmm.2011.05.011DOI Listing
August 2011

The association of microRNA expression with prognosis and progression in early-stage, non-small cell lung adenocarcinoma: a retrospective analysis of three cohorts.

Clin Cancer Res 2011 Apr 24;17(7):1875-82. Epub 2011 Feb 24.

Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.

Purpose: There is increasing evidence that altered microRNA expression is associated with tumor progression and survival in cancer patients. We tested if the expression of specific microRNAs was associated with prognosis and disease progression in early-stage lung adenocarcinoma.

Experimental Design: The expression of miR-21, miR-17, and miR-155 was measured by quantitative RT-PCR in tissues from 317 non-small cell lung cancer (NSCLC) patients that originated from Maryland, Norway, and Japan. Kaplan-Meier and Cox regression analysis evaluated associations of microRNA expression with cancer-specific mortality and disease-free survival.

Results: Elevated miR-21 (HR 2.06, 1.13-3.75), miR-17 (HR 2.00, 1.10-3.61), and miR-155 (HR 2.37, 1.27-4.42) was associated with worse cancer-specific mortality in the Maryland cohort. These were evaluated in two additional cohorts and only miR-21 was associated with worse cancer-specific mortality in the Norwegian cohort (HR 2.78, 1.22-6.31) and worse relapse-free survival in the Japanese cohort (HR 2.82, 1.57-5.07). More advanced stage tumors expressed significantly higher levels of miR-21 compared with TNM stage I tumors. TNM stage I patients were evaluated separately and high levels of miR-21 was associated with worse cancer-specific mortality (HR 2.16, 1.11-4.21) and relapse-free survival (3.40, 1.57-7.36) independent of other clinical factors.

Conclusions: This is the first study to report that increased miR-21 expression is associated with disease progression and survival in stage I lung cancer. This suggests that expression of miR-21 may contribute to lung carcinogenesis and serve as a therapeutic target or early-stage prognostic biomarker for lung adenocarcinoma.
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http://dx.doi.org/10.1158/1078-0432.CCR-10-2961DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3477786PMC
April 2011

Sex differences in susceptibility to PAHs is an intrinsic property of human lung adenocarcinoma cells.

Lung Cancer 2011 Mar 15;71(3):264-70. Epub 2010 Oct 15.

Section for Toxicology, Department of Chemical and Biological Working Environment, National Institute of Occupational Health, Oslo, Norway.

Recent epidemiological studies have disputed whether females are at increased risk of lung cancer compared to males. However, several molecular studies are in support of an increased susceptibility to tobacco smoke carcinogens among females. Our earlier findings suggest that women display higher levels of smoking-induced bulky/hydrophobic DNA adducts which may be related to an increased expression of CYP1A1 in their lungs, compared to men. In this in vitro study, 11 lung adenocarcinoma cell lines, 6 of male and 5 of female origin, were exposed to benzo[a]pyrene, cigarette smoke condensate (CSC), or vehicle control. Subsequent expression analysis of genes in the polycyclic aromatic hydrocarbon bioactivation pathway was conducted with Real-Time RT-PCR. DNA adducts were measured in benzo[a]pyrene-exposed cells by ³²P-postlabelling analysis, and CYP1 activity was measured by EROD assay. Analysis of benzo[a]pyrene-DNA adducts showed higher levels of adducts in cell lines from women compared to cell lines from men (p=0.03). The results also revealed significant sex differences in CYP1A1 gene expression, both in untreated cells (p=0.03), and in cells exposed to benzo[a]pyrene (p=0.017) and cigarette smoke condensate (p=0.0043). In CSC-exposed cells, significantly higher levels of CYP1 activity was found in cell lines of female origin (p=0.049). These results are in support of the previously published in vivo data, providing evidence for a higher susceptibility to PAH of women's lungs.
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http://dx.doi.org/10.1016/j.lungcan.2010.09.006DOI Listing
March 2011

Serum estrogen and tumor-positive estrogen receptor-alpha are strong prognostic classifiers of non-small-cell lung cancer survival in both men and women.

Carcinogenesis 2010 Oct 20;31(10):1778-86. Epub 2010 Aug 20.

Laboratory of Human Carcinogenesis, National Cancer Institute, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892, USA.

The role of tumor estrogen receptors (ERs) and serum estrogen in lung cancer is inconclusive. We investigated the hypothesis that ERs and functional single-nucleotide polymorphisms in the estrogen biosynthesis pathway are associated with poorer lung cancer survival. Lung cancer patients (n = 305) from a National Cancer Institute-Maryland (NCI-MD) case-case cohort in the Baltimore metropolitan area were used as a test cohort. To validate, 227 cases from the NCI-MD case-control cohort and 293 cases from a Norwegian lung cancer cohort were studied. Information on demographics, tobacco and reproductive histories was collected in an interviewer-administered questionnaire. Serum estrogen, progesterone, tumor messenger RNA expression of hormone receptors and germ line DNA polymorphisms were analyzed for associations with lung cancer survival. Patients in the highest tertile of serum estrogen had worse survival in all three cohorts (P combined < 0.001). Furthermore, the variant allele of estrogen receptor alpha (ER-α) polymorphism (rs2228480) was significantly associated with increased tumor ER-α levels and worse survival in all three cohorts [hazard ratio (HR) = 2.59, 95% confidence interval (CI): 1.20- 4.01; HR = 1.76, 95% CI: 1.08-2.87 and HR = 2.85, 95% CI: 1.31-4.36). Other polymorphisms associated with lower serum estrogen correlated with improved survival. Results were independent of gender and hormone replacement therapy. We report a significant association of increased serum estrogen with poorer survival among lung cancer male and female patients. Understanding the genetic control of estrogen biosynthesis and response in lung cancer could lead to improved prognosis and therapy.
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http://dx.doi.org/10.1093/carcin/bgq156DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2981456PMC
October 2010

Importance of CYP1A1 and CYP1B1 in bioactivation of benzo[a]pyrene in human lung cell lines.

Toxicol Lett 2010 Feb 30;192(2):221-8. Epub 2009 Oct 30.

Department of Chemical and Biological Working Environment, National Institute of Occupational Health, Oslo, Norway.

Polycyclic aromatic hydrocarbons are ubiquitous environmental pollutants classified as carcinogens in humans and rodents. The cytochromes P4501A1 and 1B1 have both shown capacity to carry out bioactivation of the prototype PAH, benzo[a]pyrene (B[a]P) to its ultimate carcinogenic B[a]P-diol-epoxide-I-1 form. The part played by each enzyme in human lung cells, however, has not been clarified. To get further insight into their individual role in the metabolic activation of B[a]P, RNA-interference was used to down-regulate CYP1A1 and/or CYP1B1 gene expression in the human lung cell lines BEP2D and NCIH2009. Fluorescence-HPLC analysis revealed that formation of B[a]P-tetrol-I-1 (hydrolyzed form of the corresponding diol-epoxide) was dependent primarily on CYP1A1. In cells without down-regulation of CYP1A1, the B[a]P-tetrol-I-1 was the major tested isomer formed. In contrast, the B[a]P-cis- and trans-7,8-dihydrodiol isomers were readily formed in cells expressing high levels of either CYP-gene. Simultaneous down-regulation of CYP1A1 and CYP1B1 mRNA resulted in low levels of metabolites overall. Residual unmetabolized B[a]P levels followed the expression of CYP1A1 in an inverse manner. In conclusion, these results indicate a major role of CYP1A1 in the bioactivation of B[a]P to carcinogenic B[a]P-diol-epoxides and in overall metabolism of B[a]P in human lung cell lines. In contrast, both CYP1A1 and CYP1B1 contribute significantly to the formation of the B[a]P-cis- and trans-7,8-dihydrodiol isomers.
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http://dx.doi.org/10.1016/j.toxlet.2009.10.025DOI Listing
February 2010

Spinal cord long-term potentiation (LTP) is associated with increased dorsal horn gene expression of IL-1beta, GDNF and iNOS.

Eur J Pain 2010 Mar 12;14(3):255-60. Epub 2009 Jul 12.

National Institute of Occupational Health, Oslo, Norway.

Previous data show that spinal cord long-term potentiation (LTP) can be induced by electrical high-frequency stimulation (HFS) conditioning applied to the sciatic nerve. It has been suggested that the cellular events leading to this form of plasticity may contribute to central hyperalgesia. In the present study, extracellular recordings from single dorsal horn neurons and quantitative real-time reverse-transcriptase polymerase chain reaction (RT-PCR) on rat dorsal horn tissue were used to examine whether maintenance of spinal LTP is associated with changes in gene expression of the proinflammatory interleukin-1beta (IL-1beta), glial cell-line derived neurotrophic factor (GDNF), inducible nitric oxide synthase (iNOS), p38 mitogen-activated protein kinase (p38 MAPK), cyclooxygenase 2 (COX2) and tumor necrosis factor alpha (TNFalpha). The data demonstrated that the HFS conditioning induced a robust increase in the dorsal horn C-fibre responses, which outlasted the duration of the experiments of 6h (p<0.05, HFS vs. control). Moreover, a significant increase in the expression of mRNA for IL-1beta, GDNF and iNOS were observed 6h following the HFS conditioning (p<0.05, HFS vs. control). For the first time we show that spinal cord LTP is associated with an increased dorsal horn expression of the genes for IL-1beta, GDNF and iNOS.
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http://dx.doi.org/10.1016/j.ejpain.2009.05.016DOI Listing
March 2010

Biotransformation of benzo[a]pyrene in Ahr knockout mice is dependent on time and route of exposure.

Chem Res Toxicol 2009 Mar;22(3):584-91

Section for Toxicology, The National Institute of Occupational Health, P.O. Box 8149 Dep., N-0033 Oslo, Norway.

Benzo[a]pyrene (BP) is an ubiquitous environmental pollutant with potent mutagenic and carcinogenic properties. The Ah receptor (Ahr) is important in the metabolic activation of BP and is therefore central to BP-induced carcinogenesis. Although Ahr(-/-) mice are refractory to BP-induced carcinogenesis, higher levels of BP-DNA and -protein adducts were formed in them than in wild-type mice. These results indicated the presence of an Ahr-independent and/or a slower biotransformation of BP in Ahr knockout mice. To address this issue further, we have now performed a time-course experiment, with mice receiving a single oral dose of BP (100 mg/kg). Wild-type mice have an effective clearance of BP metabolites, mainly through 3-hydroxybenzo[a]pyrene and 9-hydroxybenzo[a]pyrene in the feces with reduced levels of DNA and protein adducts in the examined tissues. On the other hand, the Ahr(-/-) mice appear to have a lower metabolic clearance of BP resulting in increased levels of DNA and protein adducts and of unmetabolized BP. In addition, we have performed an administration route experiment and found that skin-exposed Ahr(-/-) mice showed lower levels of protein adducts along with markedly reduced P450 1B1 expression, but only in the exposed area, as compared with the wild-type mice. In addition, the systemic uptake of BP is increased in the Ahr(-/-) mice as compared with the wild-type mice. Hence, the lack of a functional Ah receptor results in an Ahr-independent biotransformation of BP with a slower clearance of BP and higher levels of DNA and protein adducts, but the distribution and levels of BP and BP-protein adducts are clearly dependent on the route of exposure.
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http://dx.doi.org/10.1021/tx8003664DOI Listing
March 2009

Quantitative analysis of benzo[a]pyrene biotransformation and adduct formation in Ahr knockout mice.

Toxicol Lett 2006 Dec 16;167(3):173-82. Epub 2006 Oct 16.

Section for Toxicology, National Institute of Occupational Health, P.O. Box 8149 Dep., N-0033 Oslo, Norway.

Benzo[a]pyrene (BP) is an ubiquitous environmental pollutant with potent mutagenic and carcinogenic properties. The Ah receptor (Ahr) is involved in the metabolic activation of BP and is therefore important in the induction of chemical carcinogenesis. In this study, the relationship between Ahr genotype and biotransformation of BP in internal organs was investigated in Ahr (+/+), Ahr (+/-) and Ahr (-/-) mice. The mice were treated with BP (100mg/kg) by gavage. Gene expression was measured after 24h by real-time RT-PCR and showed induction of Cyp1a1 in liver and lung, and Cyp1b1 in lung in both Ahr (+/+) and Ahr (+/-). No induction of the Cyp genes was observed in the Ahr (-/-). There was a significant basal expression of Cyp1b1 in the liver of all genotypes, and this expression was independent of the BP exposure. Analyzed by HPLC-fluorescence, there were increased levels of protein and DNA adducts, metabolites, conjugates and unmetabolized BP in the internal organs of Ahr (-/-) as compared to Ahr (+/+) and Ahr (+/-) mice. This may be partly explained by a delayed bioactivation of BP in the Ahr deficient mice. The BP metabolism observed in the Ahr (-/-) mice is also evidence of an Ahr independent biotransformation of BP.
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http://dx.doi.org/10.1016/j.toxlet.2006.09.005DOI Listing
December 2006

Sex differences in risk of lung cancer: Expression of genes in the PAH bioactivation pathway in relation to smoking and bulky DNA adducts.

Int J Cancer 2006 Aug;119(4):741-4

Department of Toxicology, National Institute of Occupational Health, Oslo, Norway.

It is controversial whether women have a higher lung cancer susceptibility compared to men. We previously reported higher levels of smoking-related bulky DNA adducts in female lungs. In a pilot study (27 cases), we also found a higher level of female lung cytochrome P4501A1 (CYP1A1) gene expression. In the present extended study we report on the pulmonary expression of several genes involved in polycyclic aromatic hydrocarbon bioactivation in relation to sex, smoking and DNA adducts. CYP1A1, CYP1B1, aryl hydrocarbon receptor and microsomal epoxide hydrolase gene expression was measured by quantitative real-time reverse transcriptase-PCR in 121 normal lung tissue samples. The expression of CYP1A1 and CYP1B1 was significantly higher among current smokers compared to ex-smokers and never-smokers. Among current smokers, females had a 3.9-fold higher median level of CYP1A1 compared to males (p = 0.011). CYP1B1 expression was not related to sex. Lung DNA adducts (measured by 32P-postlabeling) were highly significantly related to CYP1A1 (p < 0.0001) irrespective of smoking-status. Our results are consistent with the hypothesis that CYP1A1 plays a significant role in lung DNA adduct formation and support a higher susceptibility to lung cancer among females.
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http://dx.doi.org/10.1002/ijc.21891DOI Listing
August 2006

Changes in gene expression of Zif, c-fos and cyclooxygenase-2 associated with spinal long-term potentiation.

Neuroreport 2005 Sep;16(13):1477-81

National Institute of Occupational Health, Pb 8149 Dep, N-0033 Oslo, Norway.

Spinal cord long-term potentiation is often studied as a model for cellular memory of nociceptive information. In the present report, extracellular single-unit recordings and quantitative real-time reverse transcriptase polymerase chain reaction were used to examine whether the induction of spinal cord long-term potentiation involves changes in expression of Zif, c-fos and cyclooxygenase-2. The data demonstrated that induction of spinal cord long-term potentiation was associated with a transient increase in the expression of Zif at 120 min (p < 0.05, long-term potentiation group vs. control group). In contrast, a decrease or no changes were observed in the expression of c-fos and cyclooxygenase-2. The transient increase of the expression of Zif is consistent with an involvement in the transition from the early to the late-phase of spinal cord long-term potentiation.
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http://dx.doi.org/10.1097/01.wnr.0000177004.19946.12DOI Listing
September 2005

Role of cell signaling in B[a]P-induced apoptosis: characterization of unspecific effects of cell signaling inhibitors and apoptotic effects of B[a]P metabolites.

Chem Biol Interact 2005 Jan;151(2):101-19

Division of Environmental Medicine, Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403 Oslo, Norway.

Here we show that several cell signaling inhibitors have effect on cyp1a1 expression and the metabolism of benzo[a]pyrene (B[a]P) in Hepa1c1c7 cells. The CYP1A1 inhibitor alpha-naphthoflavone (alpha-NF), the p53 inhibitor pifithrin-alpha (PFT-alpha), the ERK inhibitors PD98059 and U0126, and the p38 MAPK inhibitors SB202190 and PD169316 induced the expression and level of cyp1a1 protein. On the other hand, during the first h the inhibitors appeared to reduce the metabolism of B[a]P as measured by the generation of tetrols and by covalent binding of B[a]P to macromolecules. In contrast, the phosphatidylinositol-3 (PI-3) kinase inhibitor wortmannin, had neither an effect on the cyp1a1 expression nor the B[a]P-metabolism. In order to avoid these unspecific effects, we characterized the mechanisms involved in the apoptotic effects of B[a]P-metabolites. B[a]P and the B[a]P-metabolites B[a]P-7,8-DHD and BPDE-I induced apoptosis, whereas B[a]P-4,5-DHD had no effect. B[a]P, B[a]P-7,8-DHD and BPDE-I induced an accumulation and phosphorylation of p53, while the Bcl-2 proteins Bcl-xl, Bad and Bid were down-regulated. Interestingly, the levels of anti-apoptotic phospho-Bad were up-regulated in response to B[a]P as well as to B[a]P-7,8-DHD and BPDE-I. Both p38 MAPK and JNK were activated, but the p38 MAPK inhibitors were not able to inhibit BPDE-I-induced apoptosis. PFT-alpha reduced the BPDE-I-induced apoptosis, while both the PI-3 kinase inhibitor and the ERK inhibitors increased the apoptosis in combination with BPDE-I. BPDE-I also triggered apoptosis in primary cultures of rat lung cells. In conclusion, often used cell signaling inhibitors both enhanced the expression and the level of cyp1a1 and more directly acted as inhibitors of cyp1a1 metabolism of B[a]P. However, studies with the B[a]P-metabolite BPDE-I supported the previous suggestion that p53 has a role in the pro-apoptotic signaling pathway induced by B[a]P. Furthermore, these studies also show that the reactive metabolites of B[a]P induce the anti-apoptotic signals, Akt and ERK. Neither the induction nor the activity of p38 MAPK and JNK seems to be of major importance for the B[a]P-induced apoptosis.
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http://dx.doi.org/10.1016/j.cbi.2004.12.002DOI Listing
January 2005

Role of estrogen receptor in regulation of polycyclic aromatic hydrocarbon metabolic activation in lung.

Lung Cancer 2004 Sep;45(3):289-97

Department of Toxicology, National Institute of Occupational Health, PO Box 8149 Dep, N-0033 Oslo, Norway.

Epidemiological and biochemical studies have indicated that females may be at greater risk of smoking associated lung cancer compared with males. Among lung cancer patients, female smokers have been found to have higher levels of PAH-related DNA adducts and CYP1A1 gene expression in their normal lung tissue compared to male smokers. A possible role of steroid hormones in these sex differences via interactions between aryl hydrocarbon receptor and estrogen receptor mediated cellular effects has been suggested. In the present study the impact of the estrogen receptor (ERalpha) on CYP1A1 and CYP1B1 gene expression was studied in vitro in human bronchial epithelial cells. Transient transfection of the BEP2D cell line with ERalpha influenced neither constitutive expression of CYP1A1 or CYP1B1 nor induction of these genes by TCDD as measured by real-time RT-PCR. ERalpha had no effect on the constitutive or TCDD-induced enzymatic activity of CYP1A1 (EROD). We also studied the effect of steroid hormones on lung PAH metabolic activation in A/J mice. Intact and ovariectomized female mice were orally exposed to a single dose of benzo[a]pyrene. Ovariectomy did not influence the levels of either benzo[a]pyrene-derived protein or DNA adducts in the lung tissue measured by HPLC and 32P-postlabeling, respectively. In conclusion, the present data do not support the hypothesis of a role of estrogen or the ERalpha in regulating the metabolic activation of polycyclic aromatic hydrocarbons in lung.
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http://dx.doi.org/10.1016/j.lungcan.2004.02.014DOI Listing
September 2004

Expression of estrogen receptors alpha and beta in human lung tissue and cell lines.

Lung Cancer 2002 Aug;37(2):153-9

Department of Toxicology, National Institute of Occupational Health, P.O. Box 8149 Dep, N-0033 Oslo, Norway.

Epidemiological studies have indicated that females may be at greater risk of smoking associated lung cancer compared with males. Several lines of biochemical evidence support these observations. A possible role of circulating steroid hormones in the etiology of lung cancer has been hypothesized. In the present paper, we have studied the expression of the estrogen receptors (ER)-alpha and ER beta in histologically normal human lung tissue and lung tumor cell lines. Relative ER mRNA levels were measured by reverse transcriptase-PCR and normalized to the level of expression of the glyceraldehyde 3-phosphate dehydrogenase gene (GAPDH). In lung tissue, an ER alpha transcript was found at various levels in 38 out of 46 cases (83%). ER beta was expressed in all cases. The ERs were expressed at similar levels in females and males, and the levels of ER alpha and ER beta mRNA were significantly related (P<0.0001). Compared with the lung tissue, ER expression levels were lower in 16 human lung tumor cell lines and two immortalized human bronchial epithelial cell lines. Five of the tumor cell lines (31%) expressed detectable levels of ER alpha and both of the immortalized cell lines showed a weak ER alpha expression level. All cell lines expressed the ER beta. The lung cell lines BEAS-2B and DB354 showed significantly reduced cell proliferation in response to tamoxifen and a minor increased growth in response to 17 beta-estradiol. In conclusion, ER genes are abundantly expressed in both histologically normal human lung and lung tumor cell lines. This indicates a possible role of ERs in lung carcinogenesis.
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http://dx.doi.org/10.1016/s0169-5002(02)00039-9DOI Listing
August 2002