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Endocrine Connections Dec 2018We investigated the functional role of ATF2, a transcription factor normally activated via its phosphorylation in response to phospho-ERK/MAPK signals, in the outgrowth...
We investigated the functional role of ATF2, a transcription factor normally activated via its phosphorylation in response to phospho-ERK/MAPK signals, in the outgrowth of urothelial cancer. In both neoplastic and non-neoplastic urothelial cells, the expression levels of androgen receptor (AR) correlated with those of phospho-ATF2. Dihydrotestosterone treatment in AR-positive bladder cancer cells also induced the expression of phospho-ATF2 and phospho-ERK as well as nuclear translocation and transcriptional activity of ATF2. Meanwhile, ATF2 knockdown via shRNA resulted in significant decreases in cell viability, migration and invasion of AR-positive bladder cancer lines, but not AR-negative lines, as well as significant increases and decreases in apoptosis or G0/G1 cell cycle phase and S or G2/M phase, respectively. Additionally, the growth of AR-positive tumors expressing ATF2-shRNA in xenograft-bearing mice was retarded, compared with that of control tumors. ATF2 knockdown also resulted in significant inhibition of neoplastic transformation induced by a chemical carcinogen 3-methylcholanthrene, as well as the expression of Bcl-2/cyclin-A2/cyclin-D1/JUN/MMP-2, in immortalized human normal urothelial SVHUC cells stably expressing AR, but not AR-negative SVHUC cells. Finally, immunohistochemistry in surgical specimens demonstrated significant elevation of ATF2/phospho-ATF2/phospho-ERK expression in bladder tumors, compared with non-neoplastic urothelial tissues. Multivariate analysis further showed that moderate/strong ATF2 expression and phospho-ATF2 positivity were independent predictors for recurrence of low-grade tumors (hazard ratio (HR) = 2.956, P = 0.045) and cancer-specific mortality of muscle-invasive tumors (HR = 5.317, P = 0.012), respectively. Thus, ATF2 appears to be activated in urothelial cells through the AR pathway and promotes the development and progression of urothelial cancer.
PubMed: 30521479
DOI: 10.1530/EC-18-0364 -
Molecules (Basel, Switzerland) Oct 2018Isopsoralen (IPRN), one of the main effective ingredients in Linn, has a variety of biological effects, including antiosteoporotic effects. In vivo studies show that...
Isopsoralen (IPRN), one of the main effective ingredients in Linn, has a variety of biological effects, including antiosteoporotic effects. In vivo studies show that IPRN can increase bone strength and trabecular bone microstructure in a sex hormone deficiency-induced osteoporosis model. However, the mechanism underlying this osteogenic potential has not been investigated in detail. In the present study, we investigated the molecular mechanism of IPRN-induced osteogenesis in MC3T3-E1 cells. Isopsoralen promoted osteoblast differentiation and mineralization, increased calcium nodule levels and alkaline phosphatase (ALP) activity and upregulated osteoblast markers, including ALP, runt-related transcription factor 2 (RUNX2), and collagen type I alpha 1 chain (COL1A1). Furthermore, IPRN limited the nucleocytoplasmic shuttling of aryl hydrocarbon receptor (AhR) by directly binding to AhR. The AhR target gene cytochrome P450 family 1 subfamily A member 1 (CYP1A1) was also inhibited in vitro and in vivo. This effect was inhibited by the AhR agonists indole-3-carbinol (I3C) and 3-methylcholanthrene (3MC). Moreover, IPRN also increased estrogen receptor alpha (ERα) expression in an AhR-dependent manner. Taken together, these results suggest that IPRN acts as an AhR antagonist and promotes osteoblast differentiation via the AhR/ERα axis.
Topics: Animals; Calcification, Physiologic; Cell Differentiation; Cell Line; Estrogen Receptor alpha; Furocoumarins; Gene Expression Regulation; Mice; Molecular Structure; Osteoblasts; Osteogenesis; Protein Binding; Protein Transport; Receptors, Aryl Hydrocarbon
PubMed: 30314280
DOI: 10.3390/molecules23102600 -
Toxicological Sciences : An Official... Oct 2018Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants that interact in a complex manner with both the aryl hydrocarbon receptor (AhR) and...
Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants that interact in a complex manner with both the aryl hydrocarbon receptor (AhR) and estrogen receptors (ER). Their potential endocrine-disrupting activities may depend on both inhibitory AhR-ER cross-talk and on AhR-dependent metabolic production of estrogenic PAH metabolites. Here, we analyzed the impact of AhR on estrogen-like effects of PAHs, such as benzo[a]pyrene (BaP), in particular, on control of cell cycle progression/cell proliferation. Using AhR knockout variant of estrogen-sensitive human breast cancer MCF-7 cells (MCF-7 AhRKO cells), we observed that the AhR-dependent control of cytochrome P450 family 1 (CYP1) expression played a major role in formation of estrogenic BaP metabolites, most notably 3-OH-BaP, which contributed to the ER-dependent induction of cell cycle progression/cell proliferation. Both BaP metabolism and the BaP-induced S-phase transition/cell proliferation were inhibited in MCF-7 AhRKO cells, whereas these cells remained sensitive towards both endogenous estrogen 17β-estradiol or hydroxylated BaP metabolites. BaP was found to increase the activity of ER-dependent luciferase reporter gene in wild-type MCF-7 cells; however, unlike its hydroxylated metabolite, BaP failed to stimulate luciferase activity in MCF-7 AhRKO cells. Similarly, estrogen-like effects of other known estrogenic PAHs, such as benz[a]anthracene or 3-methylcholanthrene, were diminished in MCF-7 AhRKO cells. Ectopic expression of human CYP1A1 and CYP1B1 enzymes partly restored both BaP metabolism and its effects on cell proliferation. Taken together, our data suggest that the AhR-dependent metabolism of PAHs contributes significantly to the impact of PAHs on cell proliferation in estrogen-sensitive cells.
Topics: Cell Culture Techniques; Cell Cycle; Cell Proliferation; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1B1; Endocrine Disruptors; Gene Expression; Gene Knockdown Techniques; Genes, Reporter; Genetic Vectors; Humans; MCF-7 Cells; Plasmids; Polycyclic Aromatic Hydrocarbons; Receptors, Aryl Hydrocarbon; Receptors, Estrogen; Transfection
PubMed: 30137621
DOI: 10.1093/toxsci/kfy153 -
Toxicology Nov 2018Welding fumes were reclassified as a Group 1 carcinogen by the International Agency for Research on Cancer in 2017. Gas metal arc welding (GMAW) is a process widely used...
Welding fumes were reclassified as a Group 1 carcinogen by the International Agency for Research on Cancer in 2017. Gas metal arc welding (GMAW) is a process widely used in industry. Fume generated from GMAW-mild steel (MS) is abundant in iron with some manganese, while GMAW-stainless steel (SS) fume also contains significant amounts of chromium and nickel, known carcinogenic metals. It has been shown that exposure to GMAW-SS fume in A/J mice promotes lung tumors. The objective was to determine if GMAW-MS fume, which lacks known carcinogenic metals, also promotes lung tumors in mice. Male A/J mice received a single intraperitoneal injection of corn oil or the initiator 3-methylcholanthrene (MCA; 10 μg/g) and, one week later, were exposed by whole-body inhalation to GMAW-MS aerosols for 4 hours/day x 4 days/week x 8 weeks at a mean concentration of 34.5 mg/m. Lung nodules were enumerated by gross examination at 30 weeks post-initiation. GMAW-MS fume significantly increased lung tumor multiplicity in mice initiated with MCA (21.86 ± 1.50) compared to MCA/air-exposed mice (8.34 ± 0.59). Histopathological analysis confirmed these findings and also revealed an absence of inflammation. Bronchoalveolar lavage analysis also indicated a lack of lung inflammation and toxicity after short-term inhalation exposure to GMAW-MS fume. In conclusion, this study demonstrates that inhalation of GMAW-MS fume promotes lung tumors in vivo and aligns with epidemiologic evidence that shows MS welders, despite less exposure to carcinogenic metals, are at an increased risk for lung cancer.
Topics: Administration, Inhalation; Air Pollutants, Occupational; Animals; Carcinogens; Iron; Lung Neoplasms; Male; Mice; Steel; Welding
PubMed: 30055299
DOI: 10.1016/j.tox.2018.07.007 -
Drug Metabolism and Disposition: the... Sep 2018expression can be upregulated by the ligand-activated aryl hydrocarbon receptor (AHR). Based on prior observations with estrogen receptors and estrogen response...
expression can be upregulated by the ligand-activated aryl hydrocarbon receptor (AHR). Based on prior observations with estrogen receptors and estrogen response elements, we tested the hypothesis that single-nucleotide polymorphisms (SNPs) mapping hundreds of base pairs (bp) from xenobiotic response elements (XREs) might influence AHR binding and subsequent gene expression. Specifically, we analyzed DNA sequences 5 kb upstream and downstream of the gene for putative XREs. SNPs located ±500 bp of these putative XREs were studied using a genomic data-rich human lymphoblastoid cell line (LCL) model system. CYP1A1 mRNA levels were determined after treatment with varying concentrations of 3-methylcholanthrene (3MC). The rs2470893 (-1694G>A) SNP, located 196 bp from an XRE in the promoter, was associated with 2-fold variation in AHR-XRE binding in a SNP-dependent fashion. LCLs with the AA genotype displayed significantly higher AHR-XRE binding and CYP1A1 mRNA expression after 3MC treatment than did those with the GG genotype. Electrophoretic mobility shift assay (EMSA) showed that oligonucleotides with the AA genotype displayed higher LCL nuclear extract binding after 3MC treatment than did those with the GG genotype, and mass spectrometric analysis of EMSA protein-DNA complex bands identified three candidate proteins, two of which were co-immunoprecipitated with AHR. In conclusion, we have demonstrated that the rs2470893 SNP, which maps 196 bp from a promoter XRE, is associated with variations in 3MC-dependent AHR binding and expression. Similar "distant SNP effects" on AHR binding to an XRE motif and subsequent gene expression might occur for additional AHR-regulated genes.
Topics: 5' Untranslated Regions; Basic Helix-Loop-Helix Transcription Factors; Binding Sites; Cell Line, Tumor; Cytochrome P-450 CYP1A1; Cytochrome P-450 Enzyme Inducers; Enzyme Induction; Humans; Methylcholanthrene; Polymorphism, Single Nucleotide; Protein Binding; Receptors, Aryl Hydrocarbon; Response Elements; Transcription, Genetic; Xenobiotics
PubMed: 29980579
DOI: 10.1124/dmd.118.082164 -
Gastroenterology Research and Practice 2018The incidence of the upper gastrointestinal tumor has increased rapidly during recent decades. The relationship between local water pollution and the tumor is still not...
OBJECTIVE
The incidence of the upper gastrointestinal tumor has increased rapidly during recent decades. The relationship between local water pollution and the tumor is still not much clear, so this study was conducted to further investigate the local water pollution and its influence on the malignant cell transformation. Prevalence of human papillomavirus (HPV) in local esophageal cancer (EC) patients was also analyzed in Shenqiu County for the first time.
METHODS
Two-step cell transformation was used to study different sources of water in the malignant cell transformation, and the existence of 3-methylcholanthrene (3-MC) in water was analyzed from the river and shallow and deep wells. HPV DNA in tissue samples of EC patients was detected by polymerase chain reaction (PCR) and HPV diagnostic kit.
RESULTS
The river water has higher cytotoxicity than the shallow well water and induced significant cell malignant transformation, while deep well water has not shown the malignant cell transformation. In Huaihe River water, the 3-MC concentration was found higher than shallow and deep wells. An HPV infection rate was found high in patients with esophageal cancer.
CONCLUSION
Long-term consumption of polluted water can induce malignant cell transformation, and the presence of HPV may be an important cause of cancer.
PubMed: 29853858
DOI: 10.1155/2018/2028986 -
Cellular & Molecular Immunology Dec 2018
Topics: Animals; Antineoplastic Agents; Cell Differentiation; Cellular Reprogramming; Cytokines; Gold; Humans; Inflammation Mediators; Macrophages; Metal Nanoparticles; Methylcholanthrene; Mice; Neoplasms, Experimental; Oxidation-Reduction; Signal Transduction; Silver; Skin Neoplasms; Tetradecanoylphorbol Acetate; Th1 Cells; Th2 Cells
PubMed: 29799021
DOI: 10.1038/s41423-018-0046-7 -
Carcinogenesis Jul 2018The development of alternative methods to animal testing is a priority in the context of regulatory toxicology. Carcinogenesis is a field where the demand for...
The development of alternative methods to animal testing is a priority in the context of regulatory toxicology. Carcinogenesis is a field where the demand for alternative methods is particularly high. The standard rodent carcinogenicity bioassay requires a large use of animals, high costs, prolonged duration and shows several limitations, which can affect the comprehension of the human relevance of animal carcinogenesis. The cell transformation assay (CTA) has long been debated as a possible in vitro test to study carcinogenesis. This assay provides an easily detectable endpoint of oncotransformation, which can be used to anchor the exposure to the acquisition of the malignant phenotype. However, the current protocols do not provide information on either molecular key events supporting the carcinogenesis process, nor the mechanism of action of the test chemicals. In order to improve the use of this assay in the integrated testing strategy for carcinogenesis, we developed the transformics method, which combines the CTA and transcriptomics, to highlight the molecular steps leading to in vitro malignant transformation. We studied 3-methylcholanthrene (3-MCA), a genotoxic chemical able to induce in vitro cell transformation, at both transforming and subtransforming concentrations in BALB/c 3T3 cells and evaluated the gene modulation at critical steps of the experimental protocol. The results gave evidence for the potential key role of the immune system and the possible involvement of the aryl hydrocarbon receptor (AhR) pathway as the initial steps of the in vitro transformation process induced by 3-MCA, suggesting that the initiating events are related to non-genotoxic mechanisms.
Topics: 3T3 Cells; Animals; Biological Assay; Carcinogenesis; Carcinogenicity Tests; Carcinogens; Cell Transformation, Neoplastic; Methylcholanthrene; Mice; Mice, Inbred BALB C; Receptors, Aryl Hydrocarbon
PubMed: 29554273
DOI: 10.1093/carcin/bgy037 -
Frontiers in Immunology 2018An individual tumor can present intratumoral phenotypic heterogeneity, containing tumor cells with different phenotypes that do not present irreversible genetic...
An individual tumor can present intratumoral phenotypic heterogeneity, containing tumor cells with different phenotypes that do not present irreversible genetic alterations. We have developed a mouse cancer model, named GR9, derived from a methylcholanthrene-induced fibrosarcoma that was adapted to tissue culture and cloned into different tumor cell lines. The clones showed diverse MHC-I phenotypes, ranging from highly positive to weakly positive MHC-I expression. These MHC-I alterations are due to reversible molecular mechanisms, because surface MHC-I could be recovered by IFN-γ treatment. Cell clones with high MHC-I expression demonstrated low local oncogenicity and high spontaneous metastatic capacity, whereas MHC-I-low clones showed high local oncogenicity and no spontaneous metastatic capacity. Although MHC-I-low clones did not metastasize, they produced MHC-I-positive dormant micrometastases controlled by the host immune system, i.e., in a state of immunodormancy. The metastatic capacity of each clone was directly correlated with the host T-cell subpopulations; thus, a strong decrease in cytotoxic and helper T lymphocytes was observed in mice with numerous metastases derived from MHC-I positive tumor clones but a strong increase was observed in those with dormant micrometastases. Immunotherapy was administered to the hosts after excision of the primary tumor, producing a recovery in their immune status and leading to the complete eradication of overt spontaneous metastases or their decrease. According to these findings, the combination of MHC-I surface expression in primary tumor and metastases with host T-cell subsets may be a decisive indicator of the clinical outcome and response to immunotherapy in metastatic disease, allowing the identification of responders to this approach.
Topics: Animals; Cell Line, Tumor; Disease Models, Animal; Docetaxel; Fibrosarcoma; Histocompatibility Antigens Class I; Immunotherapy; Male; Methylcholanthrene; Mice, Inbred BALB C; Oligodeoxyribonucleotides; Polysaccharides
PubMed: 29434605
DOI: 10.3389/fimmu.2018.00102 -
Scientific Reports Feb 2018Cancer incidence appears to be higher amongst firefighters compared to the general population. Given that many cancers have an environmental component, their...
Cancer incidence appears to be higher amongst firefighters compared to the general population. Given that many cancers have an environmental component, their occupational exposure to products of carbon combustion such as polycyclic aromatic hydrocarbons (PAHs) is of concern. This is the first UK study identifying firefighters exposure to PAH carcinogens. Wipe samples were collected from skin (jaw, neck, hands), personal protective equipment of firefighters, and work environment (offices, fire stations and engines) in two UK Fire and Rescue Service Stations. Levels of 16 US Environmental Protection Agency (EPA) PAHs were quantified together with more potent carcinogens: 7,12-dimethylbenzo[a]anthracene, and 3-methylcholanthrene (3-MCA) (12 months post-initial testing). Cancer slope factors, used to estimate cancer risk, indicate a markedly elevated risk. PAH carcinogens including benzo[a]pyrene (B[a]P), 3-MCA, and 7,12-dimethylbenz[a]anthracene PAHs were determined on body surfaces (e.g., hands, throat), on PPE including helmets and clothing, and on work surfaces. The main exposure route would appear to be via skin absorption. These results suggest an urgent need to monitor exposures to firefighters in their occupational setting and conduct long-term follow-up regarding their health status.
Topics: 9,10-Dimethyl-1,2-benzanthracene; Benzopyrenes; Carcinogens; Environmental Monitoring; Firefighters; Humans; Incidence; Methylcholanthrene; Neoplasms; Occupational Diseases; Occupational Exposure; Polycyclic Aromatic Hydrocarbons; Protective Clothing; Skin; Skin Absorption; United Kingdom
PubMed: 29410452
DOI: 10.1038/s41598-018-20616-6