RESUMO
The cancer hazard associated with lifetime exposure to radiofrequency radiation (RFR) was examined in Sprague Dawley (SD) rats at the Ramazzini Institute (RI), Italy. There were increased incidences of gliomas and cardiac schwannomas. The translational relevance of these rare rat tumors for human disease is poorly understood. We examined the genetic alterations in RFR-derived rat tumors through molecular characterization of important cancer genes relevant for human gliomagenesis. A targeted next-generation sequencing (NGS) panel was designed for rats based on the top 23 orthologous human glioma-related genes. Single-nucleotide variants (SNVs) and small insertion and deletions (indels) were characterized in the rat gliomas and cardiac schwannomas. Translational relevance of these genetic alterations in rat tumors to human disease was determined through comparison with the Catalogue of Somatic Mutations in Cancer (COSMIC) database. These data suggest that rat gliomas resulting from life-time exposure to RFR histologically resemble low grade human gliomas but surprisingly no mutations were detected in rat gliomas that had homology to the human IDH1 p.R132 or IDH2 p.R172 suggesting that rat gliomas are primarily wild-type for IDH hotspot mutations implicated in human gliomas. The rat gliomas appear to share some genetic alterations with IDH1 wildtype human gliomas and rat cardiac schwannomas also harbor mutations in some of the queried cancer genes. These data demonstrate that targeted NGS panels based on tumor specific orthologous human cancer driver genes are an important tool to examine the translational relevance of rodent tumors resulting from chronic/life-time rodent bioassays.
Assuntos
Neoplasias Encefálicas , Glioma , Neurilemoma , Exposição à Radiação , Humanos , Ratos , Animais , Ratos Sprague-Dawley , Glioma/genética , Glioma/patologia , Mutação , Neurilemoma/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Isocitrato Desidrogenase/genética , Neoplasias Encefálicas/patologiaRESUMO
Antimony trioxide (AT) is used as a flame retardant in fabrics and plastics. Occupational exposure in miners and smelters is mainly through inhalation and dermal contact. Chronic inhalation exposure to AT particulates in B6C3F1/N mice and Wistar Han rats resulted in increased incidences and tumor multiplicities of alveolar/bronchiolar carcinomas (ABCs). In this study, we demonstrated Kras (43%) and Egfr (46%) hotspot mutations in mouse lung tumors (n = 80) and only Egfr (50%) mutations in rat lung tumors (n = 26). Interestingly, there were no differences in the incidences of these mutations in ABCs from rats and mice at exposure concentrations that did and did not exceed the pulmonary overload threshold. There was increased expression of p44/42 mitogen-activated protein kinase (MAPK) (Erk1/2) protein in ABCs harboring mutations in Kras and/or Egfr, confirming the activation of MAPK signaling. Transcriptomic analysis indicated significant alterations in MAPK signaling such as ephrin receptor signaling and signaling by Rho-family GTPases in AT-exposed ABCs. In addition, there was significant overlap between transcriptomic data from mouse ABCs due to AT exposure and human pulmonary adenocarcinoma data. Collectively, these data suggest chronic AT exposure exacerbates MAPK signaling in ABCs and, thus, may be translationally relevant to human lung cancers.
Assuntos
Adenocarcinoma Bronquioloalveolar , Neoplasias Pulmonares , Camundongos , Ratos , Humanos , Animais , Proteínas Proto-Oncogênicas p21(ras)/genética , Adenocarcinoma Bronquioloalveolar/genética , Adenocarcinoma Bronquioloalveolar/patologia , Proteínas Quinases Ativadas por Mitógeno , Exposição por Inalação/efeitos adversos , Ratos Wistar , Camundongos Endogâmicos , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Receptores ErbB/genéticaRESUMO
Rodent alveolar/bronchiolar carcinomas (ABC) that arise either spontaneously or due to chemical exposure are similar to a subtype of lung adenocarcinomas in humans. B6C3F1/N mice and F344/NTac rats exposed to cobalt metal dust (CMD) by inhalation developed ABCs in a dose dependent manner. In CMD-exposed mice, the incidence of Kras mutations in ABCs was 67% with 80% of those being G to T transversions on codon 12 suggesting a role of oxidative stress in the pathogenesis. In vitro studies, such as DMPO (5,5-dimethyl-1-pyrroline N-oxide) immune-spin trapping assay, and dihydroethidium (DHE) fluorescence assay on A549 and BEAS-2B cells demonstrated increased oxidative stress due to cobalt exposure. In addition, significantly increased 8-oxo-dG adducts were demonstrated by immunohistochemistry in lungs from mice exposed to CMD for 90 days. Furthermore, transcriptomic analysis on ABCs arising spontaneously or due to chronic CMD-exposure demonstrated significant alterations in canonical pathways related to MAPK signaling (IL-8, ErbB, Integrin, and PAK pathway) and oxidative stress (PI3K/AKT and Melatonin pathway) in ABCs from CMD-exposed mice. Oxidative stress can stimulate PI3K/AKT and MAPK signaling pathways. Nox4 was significantly upregulated only in CMD-exposed ABCs and NOX4 activation of PI3K/AKT can lead to increased ROS levels in human cancer cells. The gene encoding Ereg was markedly up-regulated in CMD-exposed mice. Oncogenic KRAS mutations have been shown to induce EREG overexpression. Collectively, all these data suggest that oxidative stress plays a significant role in CMD-induced pulmonary carcinogenesis in rodents and these findings may also be relevant in the context of human lung cancers.
Assuntos
Neoplasias Brônquicas/induzido quimicamente , Cobalto/toxicidade , Neoplasias Pulmonares/induzido quimicamente , Estresse Oxidativo/efeitos dos fármacos , Células A549 , Adenocarcinoma Bronquioloalveolar/induzido quimicamente , Adenocarcinoma Bronquioloalveolar/patologia , Animais , Neoplasias Brônquicas/patologia , Carcinogênese/induzido quimicamente , Linhagem Celular , Relação Dose-Resposta a Droga , Poeira , Feminino , Humanos , Neoplasias Pulmonares/patologia , Masculino , Camundongos , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Alvéolos Pulmonares/patologia , Ratos , Ratos Endogâmicos F344RESUMO
Ginkgo biloba extract (GBE) is used in traditional Chinese medicine as a herbal supplement for improving memory. Exposure of B6C3F1/N mice to GBE in a 2-year National Toxicology Program (NTP) bioassay resulted in a dose-dependent increase in hepatocellular carcinomas (HCC). To identify key microRNAs that modulate GBE-induced hepatocarcinogenesis, we compared the global miRNA expression profiles in GBE-exposed HCC (GBE-HCC) and spontaneous HCC (SPNT-HCC) with age-matched vehicle control normal livers (CNTL) from B6C3F1/N mice. The number of differentially altered miRNAs in GBE-HCC and SPNT-HCC was 74 (52 up and 22 down) and 33 (15 up and 18 down), respectively. Among the uniquely differentially altered miRNAs in GBE-HCC, miR-31 and one of its predicted targets, Cdk1 were selected for functional validation. A potential miRNA response element (MRE) in the 3'-untranslated regions (3'-UTR) of Cdk1 mRNA was revealed by in silico analysis and confirmed by luciferase assays. In mouse hepatoma cell line HEPA-1 cells, we demonstrated an inverse correlation between miR-31 and CDK1 protein levels, but no change in Cdk1 mRNA levels, suggesting a post-transcriptional effect. Additionally, a set of miRNAs (miRs-411, 300, 127, 134, 409-3p, and 433-3p) that were altered in the GBE-HCCs were also altered in non-tumor liver samples from the 90-day GBE-exposed group compared to the vehicle control group, suggesting that some of these miRNAs could serve as potential biomarkers for GBE exposure or hepatocellular carcinogenesis. These data increase our understanding of miRNA-mediated epigenetic regulation of GBE-mediated hepatocellular carcinogenesis in B6C3F1/N mice.
Assuntos
Biomarcadores Tumorais/genética , Carcinoma Hepatocelular/genética , Transformação Celular Neoplásica/genética , Neoplasias Hepáticas/genética , MicroRNAs/genética , Extratos Vegetais/toxicidade , Transcriptoma , Regiões 3' não Traduzidas , Animais , Biomarcadores Tumorais/metabolismo , Proteína Quinase CDC2/genética , Proteína Quinase CDC2/metabolismo , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Transformação Celular Neoplásica/induzido quimicamente , Transformação Celular Neoplásica/metabolismo , Epigênese Genética , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Ginkgo biloba , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/metabolismo , Masculino , Camundongos , MicroRNAs/metabolismo , Fatores de TempoRESUMO
Human exposure to pentabromodiphenyl ether (PBDE) mixture (DE-71) and its PBDE-47 congener can occur both in utero and during lactation. Here, we tested the hypothesis that PBDE-induced neonatal hepatic transcriptomic alterations in Wistar Han rat pups can inform on potential toxicity and carcinogenicity after longer term PBDE exposures. Wistar Han rat dams were exposed to either DE-71 or PBDE-47 daily from gestation day (GD 6) through postnatal day 4 (PND 4). Total plasma thyroxine (T4) was decreased in PND 4 pups. In liver, transcripts for CYPs and conjugation enzymes, Nrf2, and ABC transporters were upregulated. In general, the hepatic transcriptomic alterations after exposure to DE-71 or PBDE-47 were similar and provided early indicators of oxidative stress and metabolic alterations, key characteristics of toxicity processes. The transcriptional benchmark dose lower confidence limits of the most sensitive biological processes were lower for PBDE-47 than for the PBDE mixture. Neonatal rat liver transcriptomic data provide early indicators on molecular pathway alterations that may lead to toxicity and/or carcinogenicity if the exposures continue for longer durations. These early toxicogenomic indicators may be used to help prioritize chemicals for a more complete toxicity and cancer risk evaluation.
Assuntos
Éteres Difenil Halogenados/toxicidade , Fígado/efeitos dos fármacos , Exposição Materna/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal/patologia , Transcriptoma/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Feminino , Éteres Difenil Halogenados/sangue , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/sangue , Ratos , Ratos WistarRESUMO
Epigenetic modifications, such as DNA methylation, play an important role in carcinogenesis. In a recent NTP study, chronic exposure of B6C3F1/N mice to Ginkgo biloba extract (GBE) resulted in a high incidence of hepatocellular carcinomas (HCC). Genome-wide promoter methylation profiling on GBE-exposed HCC (2000 mg/kg group), spontaneous HCC (vehicle-control group), and age-matched vehicle control liver was performed to identify differentially methylated genes in GBE-exposed HCC and spontaneous HCC. DNA methylation alterations were correlated to the corresponding global gene expression changes. Compared to control liver, 1296 gene promoters (719 hypermethylated, 577 hypomethylated) in GBE-exposed HCC and 738 (427 hypermethylated, 311 hypomethylated) gene promoters in spontaneous HCC were significantly differentially methylated, suggesting an impact of methylation on GBE-exposed HCC. Differential methylation of promoter regions in relevant cancer genes (cMyc, Spry2, Dusp5) and their corresponding differential gene expression was validated by quantitative pyrosequencing and qRT-PCR, respectively. In conclusion, we have identified differentially methylated promoter regions of relevant cancer genes altered in GBE-exposed HCC compared to spontaneous HCC. Further study of unique sets of differentially methylated genes in chemical-exposed mouse HCC could potentially be used to differentiate treatment-related tumors from spontaneous-tumors in cancer bioassays and provide additional understanding of the underlying epigenetic mechanisms of chemical carcinogenesis.
Assuntos
Carcinoma Hepatocelular/induzido quimicamente , Metilação de DNA/efeitos dos fármacos , Neoplasias Hepáticas/induzido quimicamente , Extratos Vegetais/efeitos adversos , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Epigênese Genética/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Estudo de Associação Genômica Ampla , Ginkgo biloba , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Masculino , Camundongos Endogâmicos , Extratos Vegetais/administração & dosagem , Regiões Promotoras Genéticas , Reprodutibilidade dos Testes , Testes de Toxicidade CrônicaRESUMO
This article describes data related to the research article entitled "Carcinogenic activity of pentabrominated diphenyl ether mixture (DE-71) in rats and mice" (Dunnick et al., 2018). PBDE-induced hepatocellular tumors harbored Hras and Ctnnb1 mutations and the methods for these studies are provided. Tissue levels of PBDE congeners in rats and mice after oral exposure to PBDE mixture increased with increasing dose of PBDE. There was no correlation between AhR status and the incidence of hepatocellular tumors in female Wistar Han rats. This manuscript provides additional information on the methods for conducting mutational analysis, PBDE tissue level determinations, and AhR genotyping.
RESUMO
Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide; however, the mutational properties of HCC-associated carcinogens remain largely uncharacterized. We hypothesized that mechanisms underlying chemical-induced HCC can be characterized by evaluating the mutational spectra of these tumors. To test this hypothesis, we performed exome sequencing of B6C3F1/N HCCs that arose either spontaneously in vehicle controls ( n = 3) or due to chronic exposure to gingko biloba extract (GBE; n = 4) or methyleugenol (MEG; n = 3). Most archived tumor samples are available as formalin-fixed paraffin-embedded (FFPE) blocks, rather than fresh-frozen (FF) samples; hence, exome sequencing from paired FF and FFPE samples was compared. FF and FFPE samples showed 63% to 70% mutation concordance. Multiple known (e.g., Ctnnb1T41A, BrafV637E) and novel (e.g., Erbb4C559S, Card10A700V, and Klf11P358L) mutations in cancer-related genes were identified. The overall mutational burden was greater for MEG than for GBE or spontaneous HCC samples. To characterize the mutagenic mechanisms, we analyzed the mutational spectra in the HCCs according to their trinucleotide motifs. The MEG tumors clustered closest to Catalogue of Somatic Mutations in Cancer signatures 4 and 24, which are, respectively, associated with benzo(a)pyrene- and aflatoxin-induced HCCs in humans. These results establish a novel approach for classifying liver carcinogens and understanding the mechanisms of hepatocellular carcinogenesis.
Assuntos
Carcinógenos/toxicidade , Exoma/genética , Perfilação da Expressão Gênica , Neoplasias Hepáticas Experimentais/genética , Fígado/efeitos dos fármacos , Mutação , Análise de Sequência de DNA/métodos , Animais , Criopreservação , DNA de Neoplasias/genética , Eugenol/análogos & derivados , Eugenol/toxicidade , Feminino , Formaldeído/química , Ginkgo biloba , Fígado/patologia , Neoplasias Hepáticas Experimentais/induzido quimicamente , Neoplasias Hepáticas Experimentais/patologia , Masculino , Camundongos Endogâmicos , Inclusão em Parafina , Extratos Vegetais/toxicidade , Reprodutibilidade dos Testes , Fixação de TecidosRESUMO
Vinylidene chloride (VDC) has been widely used in the production of plastics and flame retardants. Exposure of B6C3F1 mice to VDC in the 2-year National Toxicology Program carcinogenicity bioassay resulted in a dose-dependent increases in renal cell hyperplasia, renal cell adenoma, and renal cell carcinomas (RCCs). Among those differentially expressed genes from controls and RCC of VDC-exposed mice, there was an overrepresentation of genes from pathways associated with chronic xenobiotic and oxidative stress as well as c-Myc overexpression and dysregulation of TP53 cell cycle checkpoint and DNA damage repair pathways in RCC. Trend analysis comparing RCC, VDC-exposed kidney, and chamber control kidney showed a conservation of pathway dysregulation in terms of overrepresentation of xenobiotic and oxidative stress, and DNA damage and cell cycle checkpoint pathways in both VDC-exposed kidney and RCC, suggesting that these mechanisms play a role in the pathogenesis of RCC in VDC-exposed mice.
Assuntos
Carcinoma de Células Renais , Dicloroetilenos/toxicidade , Neoplasias Renais , Estresse Oxidativo/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Proteína Supressora de Tumor p53/genética , Animais , Carcinoma de Células Renais/induzido quimicamente , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/patologia , Carcinoma de Células Renais/fisiopatologia , Relação Dose-Resposta a Droga , Feminino , Perfilação da Expressão Gênica , Rim/efeitos dos fármacos , Rim/patologia , Neoplasias Renais/induzido quimicamente , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Neoplasias Renais/fisiopatologia , Masculino , Camundongos , Mutação , Testes de Toxicidade Crônica , Proteína Supressora de Tumor p53/metabolismoRESUMO
The cell of origin of hepatoblastoma (HB) in humans and mice is unknown; it is hypothesized to be a transformed hepatocyte, oval cell, or hepatic progenitor cell. In mice, current dogma is that HBs arise from preexisting hepatocellular neoplasms as a result of further neoplastic transformation. However, there is little evidence supporting this direct relationship. To better understand the relationship between hepatocellular carcinoma (HCC) and HB and determine molecular similarities between mouse and human HB, global gene expression analysis and targeted mutation analysis were performed using HB, HCC, and adjacent liver from the same animals in a recent National Toxicology Program bioassay. There were significant differences in Hras and Ctnnb1 mutation spectra, and by microarray, HBs showed dysregulation of embryonic development, stem cell pluripotency, and genomic imprinting compared to HCC. Meta-analysis showed similarities between HB, early mouse embryonic liver, and hepatocyte-derived stem/progenitor cells compared to HCC. Our data show that there are striking differences between HB and HCC and suggest that HB is a significantly different entity that may arise from a hepatic precursor cell. Furthermore, mouse HB is similar to the human disease at the pathway level and therefore is likely a relevant model for evaluating human cancer hazard.
Assuntos
Carcinoma Hepatocelular/genética , Perfilação da Expressão Gênica/métodos , Genômica/métodos , Hepatoblastoma/genética , Neoplasias Hepáticas/genética , Animais , Carcinoma Hepatocelular/metabolismo , Hepatoblastoma/metabolismo , Humanos , Imuno-Histoquímica , Fígado/química , Neoplasias Hepáticas/metabolismo , Camundongos , Análise de Sequência com Séries de Oligonucleotídeos , Patologia Molecular , ToxicologiaRESUMO
Rodent lung tumors are morphologically similar to a subtype of human lung adenocarcinomas. The objective of this study was to evaluate Kirsten rat sarcoma oncogene homolog (Kras), epidermal growth factor receptor (Egfr), and tumor protein 53 (Tp53) mutations, which are relevant to human lung cancer, in cobalt metal dust (CMD)-induced alveolar/bronchiolar tumors of B6C3F1/N mice and F344/NTac rats. Kras mutations were detected in 67% (mice) and 31% (rats) of CMD-induced lung tumors and were predominantly exon 1 codon 12 G to T transversions (80% in mice and 57% in rats). Egfr mutations were detected in 17% (both mice and rats) of CMD-induced lung tumors and were predominantly in exon 20 with 50% G to A transitions (mice and rats). Tp53 mutations were detected in 19% (mice) and 23% (rats) of CMD-induced lung tumors and were predominant in exon 5 (mice, 69% transversions) and exon 6 (rats, all transitions). No mutations were observed for these genes in spontaneous lung tumors or normal lungs from untreated controls. Ames assay indicated that CMD is mutagenic in the absence but not in the presence of S9 mix. Thus, the mutation data (G to T transversions) and Ames assay results suggest that oxidative damage to DNA may be a contributing factor in CMD-induced pulmonary carcinogenesis in rodents.
Assuntos
Adenocarcinoma Bronquioloalveolar/induzido quimicamente , Adenocarcinoma Bronquioloalveolar/genética , Cobalto/toxicidade , Receptores ErbB/genética , Genes p53/genética , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Adenocarcinoma Bronquioloalveolar/patologia , Animais , Análise Mutacional de DNA , DNA de Neoplasias/biossíntese , DNA de Neoplasias/genética , Poeira , Receptores ErbB/efeitos dos fármacos , Éxons/genética , Feminino , Genes p53/efeitos dos fármacos , Exposição por Inalação , Neoplasias Pulmonares/patologia , Masculino , Camundongos , Testes de Mutagenicidade , Mutação/efeitos dos fármacos , Proteínas Proto-Oncogênicas p21(ras)/efeitos dos fármacos , RatosRESUMO
Obliterative bronchiolitis (OB) is an irreversible lung disease characterized by progressive fibrosis in the small airways with eventual occlusion of the airway lumens. OB is most commonly associated with lung transplant rejection; however, OB has also been diagnosed in workers exposed to artificial butter flavoring (ABF) vapors. Research has been limited by the lack of an adequate animal model of OB, and as a result the mechanism(s) is unclear and there are no effective treatments for this condition. Exposure of rats to the ABF component, 2,3-pentanedione (PD) results in airway lesions that are histopathologically similar to those in human OB. We used this animal model to evaluate changes in gene expression in the distal bronchi of rats with PD-induced OB. Male Wistar Han rats were exposed to 200 ppm PD or air 6 h/d, 5 d/wk for 2-wks. Bronchial tissues were laser microdissected from serial sections of frozen lung. In exposed lungs, both fibrotic and non-fibrotic airways were collected. Following RNA extraction and microarray analysis, differential gene expression was evaluated. In non-fibrotic bronchi of exposed rats, 4683 genes were significantly altered relative to air-exposed controls with notable down-regulation of many inflammatory cytokines and chemokines. In contrast, in fibrotic bronchi, 3807 genes were significantly altered with a majority of genes being up-regulated in affected pathways. Tgf-ß2 and downstream genes implicated in fibrosis were significantly up-regulated in fibrotic lesions. Genes for collagens and extracellular matrix proteins were highly up-regulated. In addition, expression of genes for peptidases and peptidase inhibitors were significantly altered, indicative of the tissue remodeling that occurs during airway fibrosis. Our data provide new insights into the molecular mechanisms of OB. This new information is of potential significance with regard to future therapeutic targets for treatment.
Assuntos
Brônquios/metabolismo , Bronquiolite Obliterante/patologia , Regulação para Baixo/efeitos dos fármacos , Pentanonas/toxicidade , Regulação para Cima/efeitos dos fármacos , Animais , Brônquios/patologia , Bronquiolite Obliterante/induzido quimicamente , Bronquiolite Obliterante/genética , Modelos Animais de Doenças , Fibrose/patologia , Imuno-Histoquímica , Exposição por Inalação , Masculino , Análise de Componente Principal , RNA/isolamento & purificação , RNA/metabolismo , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Fator de Crescimento Transformador beta2/genética , Fator de Crescimento Transformador beta2/metabolismoRESUMO
A majority (â¼80%) of human malignant mesotheliomas are asbestos-related. However, non-asbestos risk factors (radiation, chemicals, and genetic factors) account for up to 30% of cases. A recent 2-year National Toxicology Program carcinogenicity bioassay showed that male F344/N rats exposed to the industrial toxicant vinylidene chloride (VDC) resulted in a marked increase in malignant mesothelioma. Global gene expression profiles of these tumors were compared to spontaneous mesotheliomas and the F344/N rat mesothelial cell line (Fred-PE) in order to characterize the molecular features and chemical-specific profiles of mesothelioma in VDC-exposed rats. As expected, mesotheliomas from control and VDC-exposed rats shared pathways associated with tumorigenesis, including cellular and tissue development, organismal injury, embryonic development, inflammatory response, cell cycle regulation, and cellular growth and proliferation, while mesotheliomas from VDC-exposed rats alone showed overrepresentation of pathways associated with pro-inflammatory pathways and immune dysfunction such as the nuclear factor kappa-light-chain-enhancer of activated B cells signaling pathway, interleukin (IL)-8 and IL-12 signaling, interleukin responses, Fc receptor signaling, and natural killer and dendritic cells signaling, as well as overrepresentation of DNA damage and repair. These data suggest that a chronic, pro-inflammatory environment associated with VDC exposure may exacerbate disturbances in oncogene, growth factor, and cell cycle regulation, resulting in an increased incidence of mesothelioma.
Assuntos
Dicloroetilenos/toxicidade , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Doenças do Sistema Imunitário/induzido quimicamente , Inflamação/induzido quimicamente , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/genética , Mesotelioma/induzido quimicamente , Mesotelioma/genética , Animais , Linhagem Celular Tumoral , Dano ao DNA , Feminino , Genes cdc/efeitos dos fármacos , Doenças do Sistema Imunitário/imunologia , Inflamação/fisiopatologia , Masculino , Mesotelioma Maligno , Análise em Microsséries , Neoplasias Peritoneais/induzido quimicamente , Neoplasias Peritoneais/patologia , RNA Neoplásico/biossíntese , Ratos , Ratos Endogâmicos F344 , Transdução de Sinais/efeitos dos fármacos , Neoplasias Testiculares/induzido quimicamente , Neoplasias Testiculares/patologiaRESUMO
Aged male Fischer 344/N rats are prone to developing spontaneous peritoneal mesotheliomas that arise predominantly from the tunica vaginalis of the testes. A definitive cause for the predominance of this neoplasm in F344/N rats is unknown. Investigation of the molecular alterations that occur in spontaneous rat mesotheliomas may provide insight into their pathogenesis as well enable a better understanding regarding the mechanisms underlying chemically induced mesothelioma in rodents. Mesothelial cell function represents a complex interplay of pathways related to host defense mechanisms and maintenance of cellular homeostasis. Global gene expression profiles of spontaneous mesotheliomas from vehicle control male F344/N rats from 2-year National Toxicology Program carcinogenicity bioassays were analyzed to determine the molecular features of these tumors and elucidate tumor-specific gene expression profiles. The resulting gene expression pattern showed that spontaneous mesotheliomas are associated with upregulation of various growth factors, oncogenes, cytokines, pattern recognition response receptors, and pathogen-associated molecular patterns receptors, and the production of reactive oxygen and nitrogen species, as well as downregulation of apoptosis pathways. Alterations in these pathways in turn trigger molecular responses that stimulate cell proliferation and promote tumor survival and progression.
Assuntos
Regulação Neoplásica da Expressão Gênica , Mesotelioma/genética , Neoplasias Testiculares/genética , Animais , Carcinogênese , Ciclo Celular , Proliferação de Células , Epitélio/metabolismo , Fenômenos do Sistema Imunitário , Masculino , Mesotelioma/imunologia , Mesotelioma/patologia , Análise de Componente Principal , Ratos , Ratos Endogâmicos F344 , Neoplasias Testiculares/imunologia , Neoplasias Testiculares/patologia , Testículo/patologia , TranscriptomaRESUMO
Ginkgo biloba leaf extract (GBE) has been used for centuries in traditional Chinese medicine and today is used as an herbal supplement touted for improving neural function and for its antioxidant and anticancer effects. Herbal supplements have the potential for consumption over extended periods of time, with a general lack of sufficient data on long-term carcinogenicity risk. Exposure of B6C3F1 mice to GBE in the 2-year National Toxicology Program carcinogenicity bioassay resulted in a dose-dependent increase in hepatocellular tumors, including hepatocellular carcinoma (HCC). We show that the mechanism of hepatocarcinogenesis in GBE exposed animals is complex, involving alterations in H-ras and Ctnnb1 mutation spectra, WNT pathway dysregulation, and significantly altered gene expression associated with oncogenesis, HCC development, and chronic xenobiotic and oxidative stress compared to spontaneous HCC. This study provides a molecular context for the genetic changes associated with hepatocarcinogenesis in GBE exposed mice and illustrates the marked differences between these tumors and those arising spontaneously in the B6C3F1 mouse. The molecular changes observed in HCC from GBE-treated animals may be of relevance to those seen in human HCC and other types of cancer, and provide important data on potential mechanisms of GBE hepatocarcinogenesis.
Assuntos
Medicamentos de Ervas Chinesas/toxicidade , Ginkgo biloba/química , Neoplasias Hepáticas Experimentais/induzido quimicamente , Neoplasias Hepáticas Experimentais/genética , Administração Oral , Animais , Testes de Carcinogenicidade , Análise por Conglomerados , Relação Dose-Resposta a Droga , Medicamentos de Ervas Chinesas/administração & dosagem , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Imuno-Histoquímica , Fígado/química , Fígado/efeitos dos fármacos , Fígado/patologia , Neoplasias Hepáticas Experimentais/metabolismo , Neoplasias Hepáticas Experimentais/patologia , Masculino , Camundongos , Testes de Mutagenicidade , Estresse Oxidativo/efeitos dos fármacos , Reprodutibilidade dos Testes , Transdução de Sinais/efeitos dos fármacos , beta Catenina/metabolismoRESUMO
Lung cancer is the leading cause of cancer-related death in people and is mainly due to environmental factors such as smoking and radon. The National Toxicology Program (NTP) tests various chemicals and mixtures for their carcinogenic hazard potential. In the NTP chronic bioassay using B6C3F1 mice, the incidence of lung tumors in treated and control animals is second only to the liver tumors. In order to study the molecular mechanisms of chemically induced lung tumors, an understanding of the genetic changes that occur in spontaneous lung (SL) tumors from untreated control animals is needed. The authors have evaluated the differential transcriptomic changes within SL tumors compared to normal lungs from untreated age-matched animals. Within SL tumors, several canonical pathways associated with cancer (eukaryotic initiation factor 2 signaling, RhoA signaling, PTEN signaling, and mammalian target of rapamycin signaling), metabolism (Inositol phosphate metabolism, mitochondrial dysfunction, and purine and pyramidine metabolism), and immune responses (FcγR-mediated phagocytosis, clathrin-mediated endocytosis, interleukin 8 signaling, and CXCR4 signaling) were altered. Meta-analysis of murine SL tumors and human non-small cell lung cancer transcriptomic data sets revealed a high concordance. These data provide important information on the differential transcriptomic changes in murine SL tumors that will be critical to our understanding of chemically induced lung tumors and will aid in hazard analysis in the NTP 2-year carcinogenicity bioassays.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/patologia , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/patologia , Animais , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Feminino , Perfilação da Expressão Gênica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos , Proteínas de Neoplasias/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Especificidade da EspécieRESUMO
Aloe vera is one of the most commonly used botanicals for various prophylactic and therapeutic purposes. Recently, NTP/NCTR has demonstrated a dose-dependent increase in large intestinal tumors in F344 rats chronically exposed to Aloe barbadensis Miller (Aloe vera) non-decolorized whole leaf extract (AVNWLE) in drinking water. The morphological and molecular pathways of AVNWLE-induced large intestinal tumors in the F344 rats were compared to human colorectal cancer (hCRC) literature. Defined histological criteria were used to compare AVNWLE-induced large intestinal tumors with hCRC. The commonly mutated genes (Kras, Ctnnb1, and Tp53) and altered signaling pathways (MAPK, WNT, and TGF-ß) important in hCRC were evaluated within AVNWLE-induced large intestinal tumors. Histological evaluation of the large intestinal tumors indicated eight of twelve adenomas (Ads) and four of twelve carcinomas (Cas). Mutation analysis of eight Ads and four Cas identified point mutations in exons 1 and 2 of the Kras gene (two of eight Ads, two of four Cas), and in exon 2 of the Ctnnb1 gene (three of eight Ads, one of four Cas). No Tp53 (exons 5-8) mutations were found in Ads or Cas. Molecular pathways important in hCRC such as MAPK, WNT, and TGF-ß signaling were also altered in AVNWLE-induced Ads and Cas. In conclusion, the AVNWLE-induced large intestinal tumors in F344 rats share several similarities with hCRC at the morphological and molecular levels.
Assuntos
Aloe/química , Neoplasias Colorretais/metabolismo , Neoplasias Intestinais/induzido quimicamente , Neoplasias Intestinais/metabolismo , Extratos Vegetais/toxicidade , Adenoma/induzido quimicamente , Adenoma/metabolismo , Adenoma/patologia , Animais , Biomarcadores Tumorais/metabolismo , Neoplasias Colorretais/patologia , Modelos Animais de Doenças , Histocitoquímica , Humanos , Neoplasias Intestinais/patologia , Intestino Grosso/patologia , Folhas de Planta/química , Análise de Componente Principal , Ratos , Ratos Endogâmicos F344 , Transdução de Sinais/efeitos dos fármacosRESUMO
The incidences of alveolar/bronchiolar adenomas and carcinomas in cumene-treated B6C3F1 mice were significantly greater than those of the control animals. We evaluated these lung neoplasms for point mutations in the K-ras and p53 genes that are often mutated in humans. K-ras and p53 mutations were detected by cycle sequencing of PCR-amplified DNA isolated from paraffin-embedded neoplasms. K-ras mutations were detected in 87% of cumene-induced lung neoplasms, and the predominant mutations were exon 1 codon 12 G to T transversions and exon 2 codon 61 A to G transitions. P53 protein expression was detected by immunohistochemistry in 56% of cumene-induced neoplasms, and mutations were detected in 52% of neoplasms. The predominant mutations were exon 5, codon 155 G to A transitions, and codon 133 C to T transitions. No p53 mutations and one of seven (14%) K-ras mutations were detected in spontaneous neoplasms. Cumene-induced lung carcinomas showed loss of heterozygosity (LOH) on chromosome 4 near the p16 gene (13%) and on chromosome 6 near the K-ras gene (12%). No LOH was observed in spontaneous carcinomas or normal lung tissues examined. The pattern of mutations identified in the lung tumors suggests that DNA damage and genomic instability may be contributing factors to the mutation profile and development of lung cancer in mice exposed to cumene.
Assuntos
Derivados de Benzeno/toxicidade , Genes p53/genética , Genes ras , Neoplasias Pulmonares/genética , Proteína Supressora de Tumor p53/genética , Adenocarcinoma Bronquioloalveolar/induzido quimicamente , Adenocarcinoma Bronquioloalveolar/genética , Adenocarcinoma Bronquioloalveolar/patologia , Animais , Carcinoma/induzido quimicamente , Carcinoma/genética , Carcinoma/patologia , Códon , Éxons , Imuno-Histoquímica , Perda de Heterozigosidade , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Endogâmicos , Mutação PuntualRESUMO
National Toxicology Program (NTP) inhalation studies demonstrated that cumene significantly increased the incidence of alveolar/bronchiolar adenomas and carcinomas in B6C3F1 mice. Cumene or isopropylbenzene is a component of crude oil used primarily in the production of phenol and acetone. The authors performed global gene expression analysis to distinguish patterns of gene regulation between cumene-induced tumors and normal lung tissue and to look for patterns based on the presence or absence of K-ras and p53 mutations in the tumors. Principal component analysis segregated the carcinomas into groups with and without K-ras mutations, but failed to separate the tumors based on p53 mutation status. Expression of genes associated with the Erk MAP kinase signaling pathway was significantly altered in carcinomas with K-ras mutations compared to tumors without K-ras mutations or normal lung. Gene expression analysis also suggested that cumene-induced carcinomas with K-ras mutations have greater malignant potential than those without mutations. In addition, significance analysis of function and expression (SAFE) demonstrated expression changes of genes regulated by histone modification in carcinomas with K-ras mutations. The gene expression analysis suggested the formation of alveolar/bronchiolar carcinomas in cumene-exposed mice typically involves mutation of K-ras, which results in increased Erk MAP kinase signaling and modification of histones.
Assuntos
Derivados de Benzeno/toxicidade , Genes ras/genética , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Transdução de Sinais/genética , Adenocarcinoma Bronquioloalveolar/induzido quimicamente , Adenocarcinoma Bronquioloalveolar/genética , Adenocarcinoma Bronquioloalveolar/patologia , Animais , Feminino , Regulação Neoplásica da Expressão Gênica , Imuno-Histoquímica , Neoplasias Pulmonares/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Transdução de Sinais/fisiologiaRESUMO
Ethylene oxide is a multisite carcinogen in rodents and classified as a human carcinogen by the National Toxicology Program. In 2-year mouse studies, ethylene oxide (EO) induced lung, Harderian gland (HG), and uterine neoplasms. We evaluated representative EO-induced and equivalent spontaneous neoplasms for K-ras mutations in codons 12, 13, and 61. K-ras mutations were identified in 100% (23/23) of the EO-induced lung neoplasms and 25% (27/108) of the spontaneous lung neoplasms. Codon 12 G to T transversions were common in EO-induced lung neoplasms (21/23) but infrequent in spontaneous lung neoplasms (1/108). K-ras mutations were found in 86% (18/21) of the EO-induced HG neoplasms and 7% (2/27) of the spontaneous HG neoplasms. Codon 13 G to C and codon 12 G to T transversions were predominant in the EO-induced HG neoplasms but absent in spontaneous HG neoplasms (0/27). K-ras mutations occurred in 83% (5/6) of the EO-induced uterine carcinomas and all were codon 13 C to T transitions. These data show a strong predilection for development of K-ras mutations in EO-induced lung, Harderian gland, and uterine neoplasms. This suggests that EO specifically targets the K-ras gene in multiple tissue types and that this event is a critical component of EO-induced tumorigenesis.