-
Chemico-biological Interactions Dec 2009The response of hepatic mono-oxygenase activities to Aroclor 1254 or 3-methylcholanthrene was investigated in wild-type and Cyp1a2(-/-) mice. Cytochrome P450...
The response of hepatic mono-oxygenase activities to Aroclor 1254 or 3-methylcholanthrene was investigated in wild-type and Cyp1a2(-/-) mice. Cytochrome P450 concentrations were similar in naïve Cyp1a2(-/-) and wild-type mice. There was no difference between naïve wild-type and Cyp1a2(-/-) animals in 7-ethoxyresorufin and 7-ethoxy-4-trifluoromethylcoumarin dealkylase activities, nor was the induction response after 3-methylcholanthrene any different between the two genotypes. However, both activities were induced to a higher extent in Cyp1a2(-/-) mice after Aroclor 1254. In contrast, 7-pentoxyresorufin dealkylation activity was lower in Cyp1a2(-/-) mice and this differential was maintained during induction by both agents. 7-Methoxy- and 7-benzoxyresorufin dealkylation activities were also lower than wild-type in naïve Cyp1a2(-/-) animals and during 3-methylcholanthrene induction, but showed accelerated induction in Cyp1a2(-/-) mice with Aroclor 1254. Bufuralol 1'- and testosterone 6beta-hydroxylation activities, and P450 characteristics were evaluated 48h after inducer administration. Bufuralol 1'-hydroxylation, a sexual dimorphic activity (female>male) showed no genotype differences in naïve animals. Activity changes varied across gender and genotype, with 3-methylcholanthrene and Aroclor 1254 inducing in male Cyp1a2(-/-), and Aroclor 1254 inducing in female wild-type. Testosterone 6beta-hydroxylation activity was 16% higher in Cyp1a2(-/-) mice and neither 3-methylcholanthrene nor Aroclor 1254 elicited induction. After Aroclor 1254, a 24% increase in P450 concentration with a hypsochromic shift in the ferrous-CO maximum characteristic of CYP1A enzymes occurred in wild-type, compared to no change in either parameter in Cyp1a2(-/-) mice. Induction changes with 3-methylcholanthrene were greater in wild-type mice, a 60% increase in concentration and approximately 2 nm hypsochromic shift versus a 10% increase and approximately 1nm hypsochromic shift in Cyp1a2(-/-) mice. The study demonstrates that deletion of a single P450 can profoundly affect the induction response, as monitored with activities of other P450s, in a manner unrelated to the contribution of the deleted P450 to the activity.
Topics: Animals; Chlorodiphenyl (54% Chlorine); Cytochrome P-450 CYP1A2; Cytochrome P-450 Enzyme System; Female; Gene Deletion; Liver; Male; Methylcholanthrene; Mice; Mice, Inbred C57BL; Polychlorinated Biphenyls
PubMed: 19772856
DOI: 10.1016/j.cbi.2009.09.007 -
Journal of Experimental & Clinical... Aug 2019The chemical carcinogen 3-methylcholanthrene (3MC) binds to the aryl hydrocarbon receptor (AHR) that regulates the expression of cytochrome P450 (CYP) enzymes as CYP1B1,...
BACKGROUND
The chemical carcinogen 3-methylcholanthrene (3MC) binds to the aryl hydrocarbon receptor (AHR) that regulates the expression of cytochrome P450 (CYP) enzymes as CYP1B1, which is involved in the oncogenic activation of environmental pollutants as well as in the estrogen biosynthesis and metabolism. 3MC was shown to induce estrogenic responses binding to the estrogen receptor (ER) α and stimulating a functional interaction between AHR and ERα. Recently, the G protein estrogen receptor (GPER) has been reported to mediate certain biological responses induced by endogenous estrogens and environmental compounds eliciting an estrogen-like activity.
METHODS
Molecular dynamics and docking simulations were performed to evaluate the potential of 3MC to interact with GPER. SkBr3 breast cancer cells and cancer-associated fibroblasts (CAFs) derived from breast tumor patients were used as model system. Real-time PCR and western blotting analysis were performed in order to evaluate the activation of transduction mediators as well as the mRNA and protein levels of CYP1B1 and cyclin D1. Co-immunoprecipitation studies were performed in order to explore the potential of 3MC to trigger the association of GPER with AHR and EGFR. Luciferase assays were carried out to determine the activity of CYP1B1 promoter deletion constructs upon 3MC exposure, while the nuclear shuttle of AHR induced by 3MC was assessed through confocal microscopy. Cell proliferation stimulated by 3MC was determined as biological counterpart of the aforementioned experimental assays. The statistical analysis was performed by ANOVA.
RESULTS
We first ascertained by docking simulations the ability of 3MC to interact with GPER. Thereafter, we established that 3MC activates the EGFR/ERK/c-Fos transduction signaling through both AHR and GPER in SkBr3 cells and CAFs. Then, we found that these receptors are involved in the up-regulation of CYP1B1 and cyclin D1 as well as in the stimulation of growth responses induced by 3MC.
CONCLUSIONS
In the present study we have provided novel insights regarding the molecular mechanisms by which 3MC may trigger a physical and functional interaction between AHR and GPER, leading to the stimulation of both SkBr3 breast cancer cells and CAFs. Altogether, our results indicate that 3MC may engage both GPER and AHR transduction pathways toward breast cancer progression.
Topics: Basic Helix-Loop-Helix Transcription Factors; Breast Neoplasms; Cancer-Associated Fibroblasts; Cell Line, Tumor; Cell Proliferation; Cytochrome P-450 CYP1B1; ErbB Receptors; Extracellular Signal-Regulated MAP Kinases; Female; Gene Expression Regulation, Neoplastic; Humans; Methylcholanthrene; Molecular Conformation; Molecular Docking Simulation; Molecular Dynamics Simulation; Protein Binding; Protein Transport; Receptors, Aryl Hydrocarbon; Receptors, Estrogen; Receptors, G-Protein-Coupled; Signal Transduction; Structure-Activity Relationship
PubMed: 31370872
DOI: 10.1186/s13046-019-1337-2 -
Anesthesiology Aug 1973
Review
Topics: Anesthesia, Inhalation; Anesthetics; Animals; Biotransformation; Cytochrome P-450 Enzyme System; Drug Interactions; Electron Transport; Endoplasmic Reticulum; Environmental Exposure; Enzyme Induction; Hormones; Humans; Methylcholanthrene; Microsomes, Liver; NADH, NADPH Oxidoreductases; Phenobarbital
PubMed: 4146382
DOI: 10.1097/00000542-197308000-00009 -
International Journal of Molecular... Mar 20233-methylcholanthrene (3-MC) is a highly toxic environmental pollutant that impairs animal health. 3-MC exposure can cause abnormal spermatogenesis and ovarian...
3-methylcholanthrene (3-MC) is a highly toxic environmental pollutant that impairs animal health. 3-MC exposure can cause abnormal spermatogenesis and ovarian dysfunction. However, the effects of 3-MC exposure on oocyte maturation and embryo development remain unclear. This study revealed the toxic effects of 3-MC exposure on oocyte maturation and embryo development. 3-MC with different concentrations of 0, 25, 50, and 100 μM was applied for in vitro maturation of porcine oocytes. The results showed that 100 μM 3-MC significantly inhibited cumulus expansion and the first polar body extrusion. The rates of cleavage and blastocyst of embryos derived from 3-MC-exposed oocytes were significantly lower than those in the control group. Additionally, the rates of spindle abnormalities and chromosomal misalignments were higher than those in the control group. Furthermore, 3-MC exposure not only decreased the levels of mitochondria, cortical granules (CGs), and acetylated α-Tubulin, but also increased the levels of reactive oxygen species (ROS), DNA damage, and apoptosis. The expression of cumulus expansion and apoptosis-related genes was abnormal in 3-MC-exposed oocytes. In conclusion, 3-MC exposure disrupted the nuclear and cytoplasmic maturation of porcine oocytes through oxidative stress.
Topics: Animals; Swine; Methylcholanthrene; Oogenesis; Oocytes; Oxidative Stress; Reactive Oxygen Species; Embryonic Development; In Vitro Oocyte Maturation Techniques
PubMed: 36982641
DOI: 10.3390/ijms24065567 -
Se Pu = Chinese Journal of... Oct 2022A new method for sample pretreatment using improved QuEChERs was established, and 289 organic pollutants with health risks could be identified and quantified through gas...
A new method for sample pretreatment using improved QuEChERs was established, and 289 organic pollutants with health risks could be identified and quantified through gas chromatography-orbitrap high-resolution mass spectrometry (GC-Orbitrap HRMS). A high-resolution database of 289 environmental pollutants belonging to ten categories, including organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), phthalates (PAEs), polychlorinated biphenyls (PCBs), and other agricultural chemicals (ACs), was established for the non-targeted screening and quantitative analysis. A simple method for biological sample preparation using improved QuEChERs was proposed by combining a conventional QuEChERs method and a column purification method. After purification using a Florisil column, the lipid content was reduced by 99.9%, which significantly reduced the interference of the matrix effect observed during the analysis. Furthermore, simultaneous high-accuracy qualitative screening and quantitative analysis of the target compounds were performed through high-resolution mass spectrometry (60000 resolution) conducted in the full scan mode. The limits of quantification were 0.56-57.8 pg/g, presenting a large linear range (~10), and the recovery range was 40%-120%. Due to the high-resolution and sensitivity of Q Exactive GC-Orbitrap HRMS, the limits of quantification of the target compounds were significantly lower than those achieved through methods based on conventional chromatography and mass spectrometry. Moreover, ultratrace organic contaminants that cannot be detected by conventional methods can be accurately quantified by the proposed method. Sea cucumber samples collected at the breeding site were analyzed using the proposed high-coverage multi-objective analytical method, and more than 100 types of organic pollutants were detected; the mean contents of PAHs, ACs, PAEs, and OCPs were 157.8, 153.2, 64.4, and 46.4 ng/g dw, respectively, which were higher than those of other pollutants. Some new contaminants, such as 9-chlorofluorene, 5-chloroacenaphthene, and 3-methylcholanthrene, were detected at very low contents for the first time in the sea cucumber samples. The proposed method is simple and efficient, allows the detection of pollutants at very low contents, and provides accurate and reliable results. Thus, this high-coverage multi-objective analytical method can be widely used for broad-spectrum screening and accurate quantification of contaminants in various aquatic products, providing technical support for food safety control.
Topics: Animals; Environmental Pollutants; Gas Chromatography-Mass Spectrometry; Hydrocarbons, Chlorinated; Lipids; Mass Spectrometry; Methylcholanthrene; Pesticides; Polychlorinated Biphenyls; Polycyclic Aromatic Hydrocarbons; Sea Cucumbers
PubMed: 36222258
DOI: 10.3724/SP.J.1123.2022.04001 -
Environment International Nov 2010Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants with myriad biological effects, including carcinogenicity. We present data showing...
Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants with myriad biological effects, including carcinogenicity. We present data showing gender-specific genotoxicity in Fischer 344 transgenic BigBlue rodents exposed to 4-chlorobiphenyl (PCB3), a hydroxylated metabolite, and the positive control 3-methylcholanthrene (3-MC) where female rats are more resistant to the genotoxic effects of the test compounds compared to their male counterparts. This difference is further highlighted through our examination of gene expression, organ-specific weight changes, and tissue morphology. The purpose of the present study was to explore the complex and multifaceted issues of lower molecular weight PCBs as initiators of carcinogenesis, by examining the mutagenicity of PCB3, a hydroxylated metabolite (4'-OH-PCB3), and 3-methylcholanthrene (3-MC, positive control) in a transgenic rodent model. Previous findings indicated that PCB3 is mutagenic in the liver of male BigBlue transgenic rats under identical exposure conditions. We expected that female rats would be equally, if not more sensitive than male rats, since a 2-year carcinogenesis bioassay with Sprague-Dawley rats and commercial PCB mixtures reported much higher liver cancer rates in female than in male rats. The current study, however, revealed a similar trend in the mutation frequencies across all four treatment groups in females as reported previously in males, but increased variability among animals within each group and a lower overall effect, led to non significant differences in mutation frequencies. A closer analysis of the possible reasons for this negative result using microarray, organ weight and histology data comparisons shows that female Fischer 344 rats 1) had a higher baseline mutation frequency in the corn oil control group and greater variability than male rats; 2) responded with robust gene expression changes, which may also play a role in our observation of 3) highly increased liver, spleen, and lung weight in 3-MC and PCB3-treated female rats and thus changed distribution and kinetics of the test compounds. Our analysis indicates that female transgenic BigBlue Fischer 344 rats are more resistant to PCB3 and 3-MC genotoxicity compared to their male counterparts.
Topics: Animals; Biphenyl Compounds; Female; Gene Expression Profiling; Histocytochemistry; Liver; Lung; Male; Methylcholanthrene; Microarray Analysis; Mutagens; Mutation; Rats; Rats, Inbred F344; Rats, Transgenic; Sex Characteristics; Spleen
PubMed: 20739065
DOI: 10.1016/j.envint.2010.07.006 -
The Journal of Experimental Medicine Jan 1958The repeated administration of 3-methylcholanthrene to adolescent rats resulted in (a) a profound, incomplete, and selective depression of certain hypophyseal functions;...
The repeated administration of 3-methylcholanthrene to adolescent rats resulted in (a) a profound, incomplete, and selective depression of certain hypophyseal functions; (b) decreased growth of transplanted mammary tumors; and (c) a retardation of body growth. Only the last mentioned effect was reversed by forced feeding. The retarded rate of body growth induced by 3-methylcholanthrene was prevented by the concurrent administration of dihydrotestosterone or progesterone, or by ovariectomy; rats so treated became overweight despite the injection of 3-methylcholanthrene. Phenolic estrogens intensified the retardation of body growth induced by 3-methylcholanthrene and emaciation resulted. The administration of 3-methylcholanthrene resulted in decreased gonadotrophin production by the pituitary and the ovaries were more drastically affected by the depression of pituitary activity than the adrenals were. The compound exerted differential effects on the pituitary glands of males and females respectively. Hormonal functions of both ovary and testis were decreased in rats treated with 3-methylcholanthrene but, whilst ovarian weight was much reduced, the size of the testis was not decreased and the germinal epithelium of the male was little affected by the treatment in most instances. There was a considerable reduction of the content of alkaline phosphatase in the breast of intact rats treated with 3-methylcholanthrene but atrophy of the mammary epithelium did not occur and hyperplasia of the mammary tree was often observed. The administration of 3-methylcholanthrene considerably slowed the growth of transplanted mammary tumors characterized by high dependence on hormones and the concurrent administration of gonadotrophin restored the growth rate of the tumors. The administration of 3-methylcholanthrene or androstan-17beta-ol-3-one was only moderately effective in controlling the growth of transplanted mammary tumors characterized by low hormonal dependence; the combined administration of these compounds was highly efficacious in retarding the growth of these refractory tumors. 3-Methylcholanthrene partially retarded the growth of mammary fibroadenomas in hypophysectomized rats.
Topics: Animals; Endocrine Glands; Endocrine System; Estrogens; Female; Humans; Male; Mammary Neoplasms, Animal; Mammary Neoplasms, Experimental; Metabolism; Methylcholanthrene; Neoplasms, Experimental; Ovariectomy; Pharmaceutical Preparations; Rats
PubMed: 13481252
DOI: 10.1084/jem.107.1.13 -
Brazilian Journal of Medical and... Jul 2003Cytochrome P450 (CYP) 2A enzymes are involved in the metabolism of numerous drugs and hormones and activate different carcinogens. Human CYP2A6, mouse CYP2A5 and rat...
Cytochrome P450 (CYP) 2A enzymes are involved in the metabolism of numerous drugs and hormones and activate different carcinogens. Human CYP2A6, mouse CYP2A5 and rat CYP2A3 are orthologous enzymes that present high similarity in their amino acid sequence and share substrate specificities. However, different from the human and mouse enzyme, CYP2A3 is not expressed in the rat liver. There are limited data about expression of CYP2A3 in extrahepatic tissues and its regulation by typical CYP inducers. Therefore, the objective of the present study was to analyze CYP2A3 mRNA expression in different rat tissues by RT-PCR, and to study the influence of 3-methylcholanthrene, pyrazole and -ionone treatment on its expression. Male Wistar rats were divided into four groups of 5 rats each, and were treated ip for 4 days with 3-methylcholanthrene (25 mg/kg body weight), pyrazole (150 mg/kg body weight), -ionone (1 g/kg body weight), or vehicle. Total RNA was extracted from tissues and CYP2A3 mRNA levels were analyzed by semiquantitative RT-PCR. CYP2A3 mRNA was constitutively expressed in the esophagus, lung and nasal epithelium, but not along the intestine, liver, or kidney. CYP2A3 mRNA levels were increased in the esophagus by treatment with 3-methylcholanthrene and pyrazole (17- and 7-fold, respectively), in lung by pyrazole and -ionone (3- and 4-fold, respectively, although not statistically significant), in the distal part of the intestine and kidney by 3-methylcholanthrene and pyrazole, and in the proximal part of the intestine by pyrazole. CYP2A3 mRNA was not induced in nasal epithelium, liver or in the middle part of the intestine. These data show that, in the rat, CYP2A3 is constitutively expressed in several extrahepatic tissues and its regulation occurs through a complex mechanism that is essentially tissue specific.
Topics: Animals; Aryl Hydrocarbon Hydroxylases; Cytochrome P-450 CYP2A6; Cytochrome P450 Family 2; Enzyme Inhibitors; Gene Expression; Male; Methylcholanthrene; Mixed Function Oxygenases; Norisoprenoids; Pyrazoles; RNA, Messenger; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction
PubMed: 12845369
DOI: 10.1590/s0100-879x2003000700003 -
Scientific Reports May 2016In vitro liver models have been important tools for more than 40 years for academic research and preclinical toxicity screening by the pharmaceutical industry....
In vitro liver models have been important tools for more than 40 years for academic research and preclinical toxicity screening by the pharmaceutical industry. Hepatocytes, the highly metabolic parenchymal cells of the liver, are efficient at different metabolic chemistries depending on their relative spatial location along the sinusoid from the portal triad to the central vein. Although replicating hepatocyte metabolic zonation is vitally important for physiologically-relevant in vitro liver tissue and organ models, it is most often completely overlooked. Here, we demonstrate the creation of spatially-controlled zonation across multiple hepatocyte metabolism levels through the application of precise concentration gradients of exogenous hormone (insulin and glucagon) and chemical (3-methylcholanthrene) induction agents in a microfluidic device. Observed gradients in glycogen storage via periodic acid-Schiff staining, urea production via carbamoyl phosphatase synthetase I staining, and cell viability after exposure to allyl alcohol and acetaminophen demonstrated the in vitro creation of hepatocyte carbohydrate, nitrogen, alcohol degradation, and drug conjugation metabolic zonation. This type of advanced control system will be crucial for studies evaluating drug metabolism and toxicology using in vitro constructs.
Topics: Acetaminophen; Animals; Cell Culture Techniques; Cells, Cultured; Ethanol; Female; Glucagon; Glucose; Hepatocytes; Insulin; Lab-On-A-Chip Devices; Methylcholanthrene; Microtechnology; Nitrogen; Rats, Inbred Lew
PubMed: 27240736
DOI: 10.1038/srep26868 -
The Journal of Experimental Medicine Nov 1955Three spontaneous pulmonary adenomas of C mice, morphologically resembling those induced by methylcholanthrene or urethane, were propagated in host after host under...
Are carcinogens responsible for the superimposed neoplastic changes occurring in mouse tumor cells? The effect of methylcholanthrene and urethane on pulmonary adenomas and of methylcholanthrene on mammary carcinomas.
Three spontaneous pulmonary adenomas of C mice, morphologically resembling those induced by methylcholanthrene or urethane, were propagated in host after host under conditions such that the neoplastic cells were directly exposed, while proliferating, to one or the other of these agents. The successive periods of test lasted for more than a year in some instances, the total exposure to the carcinogens far exceeding that required to change normal pulmonary cells into adenoma cells. One of the adenomas remained unaltered, and the others underwent cancerous changes; but these took place with equal frequency in the control growths, and their occurrence was neither hastened nor delayed by the carcinogens. Two polymorphous mammary carcinomas of "milk-factor" type, with the characteristic tendency to form acini and tubules, were exposed to methylcholanthrene in the same way as the pulmonary adenomas and for periods quite as long. Their cells continued to differentiate, and in other respects underwent no significant change. Urethane had no influence on the rate of growth of the adenomas exposed to it; methylcholanthrene, on the other hand, markedly retarded the enlargement both of them and of the mammary tumors. Its inhibitory influence was not passed on from cell to cell however; when freed of the carcinogen by further transplantation, the retarded tumors grew as fast as the controls. Furthermore the retardation caused no evident delay in the occurrence of cancerous changes in the adenomas. One of the adenomas was maintained in twelve parallel lines while under test and new tumors arose in nine of them, the earliest appearing more than fifteen months after initial transfer of the growth. Always it was an adenoma solidum, this appearing almost concurrently in eight of the nine lines. In six of them it was soon followed by carcinomas, the sequence of events and the morphological findings both indicating that they had derived from it. Individually the cancers were widely various, but they were similar on the whole from line to line. Carcinomas of a wholly different aspect arose from the other adenoma undergoing cancerous change, and they were not preceded by adenoma solidum. In both instances the character of the superimposed neoplastic alterations seemed to have been determined by some inherent trait of the adenoma concerned.
Topics: Adenoma; Animals; Breast Neoplasms; Carcinogens; Humans; Lung; Lung Neoplasms; Methylcholanthrene; Mice; Neoplasms; Urethane
PubMed: 13271668
DOI: 10.1084/jem.102.5.517