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Pulmonary Inflammation and KRAS Mutation in Lung Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 33788188 DOI: 10.1007/978-3-030-63046-1_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2023]
Abstract
Chronic lung infection and lung cancer are two of the most important pulmonary diseases. Respiratory infection and its associated inflammation have been increasingly investigated for their role in increasing the risk of respiratory diseases including chronic obstructive pulmonary disease (COPD) and lung cancer. Kirsten rat sarcoma viral oncogene (KRAS) is one of the most important regulators of cell proliferation, differentiation, and survival. KRAS mutations are among the most common drivers of cancer. Lung cancer harboring KRAS mutations accounted for ~25% of the incidence but the relationship between KRAS mutation and inflammation remains unclear. In this chapter, we will describe the roles of KRAS mutation in lung cancer and how elevated inflammatory responses may increase KRAS mutation rate and create a vicious cycle of chronic inflammation and KRAS mutation that likely results in persistent potentiation for KRAS-associated lung tumorigenesis. We will discuss in this chapter regarding the studies of KRAS gene mutations in specimens from lung cancer patients and in animal models for investigating the role of inflammation in increasing the risk of lung tumorigenesis driven primarily by oncogenic KRAS.
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Dwyer-Nield LD, McArthur DG, Tennis MA, Merrick DT, Keith RL. An Improved Murine Premalignant Squamous Cell Model: Tobacco Smoke Exposure Augments NTCU-Induced Murine Airway Dysplasia. Cancer Prev Res (Phila) 2020; 14:307-312. [PMID: 33115782 DOI: 10.1158/1940-6207.capr-20-0332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/25/2020] [Accepted: 10/22/2020] [Indexed: 12/31/2022]
Abstract
Tobacco smoke-induced squamous cell lung cancer (SCC) develops from endobronchial dysplastic lesions that progress to invasive disease. A reproducible murine model recapitulating histologic progression observed in current and former smokers will advance testing of new preventive and therapeutic strategies. Previous studies show that prolonged topical application of N-nitroso-tris-chloroethylurea (NTCU) generates a range of airway lesions in sensitive mice similar to those induced by chronic tobacco smoke exposure in humans. To improve the current NTCU model and better align it with human disease, NTCU was applied to mice twice weekly for 4-5 weeks followed by a recovery period before cigarette smoke (CS) or ambient air (control) exposure for an additional 3-6 weeks. Despite the short time course, the addition of CS led to significantly more premalignant lesions (PML; 2.6 vs. 0.5; P < 0.02) and resulted in fewer alveolar macrophages (52,000 macrophages/mL BALF vs. 68,000; P < 0.05) compared with control mice. This improved NTCU + CS model is the first murine SCC model to incorporate tobacco smoke and is more amenable to preclinical studies because of the increased number of PML, decreased number of mice required, and reduced time needed for PML development.
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Affiliation(s)
- Lori D Dwyer-Nield
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Center, Aurora, Colorado
| | - Debbie G McArthur
- Research Division, Rocky Mountain Regional Veterans Administration Medical Center, Aurora, Colorado
| | - Meredith A Tennis
- Division of Pulmonary Sciences and Critical Care Medicine, School of Medicine, University of Colorado Anschutz Medical Center, Aurora, Colorado
| | - Daniel T Merrick
- Division of Pathology, School of Medicine, University of Colorado Anschutz Medical Center, Aurora, Colorado
| | - Robert L Keith
- Research Division, Rocky Mountain Regional Veterans Administration Medical Center, Aurora, Colorado. .,Division of Pulmonary Sciences and Critical Care Medicine, School of Medicine, University of Colorado Anschutz Medical Center, Aurora, Colorado
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Redente EF, Higgins DM, Dwyer-Nield LD, Orme IM, Gonzalez-Juarrero M, Malkinson AM. Differential polarization of alveolar macrophages and bone marrow-derived monocytes following chemically and pathogen-induced chronic lung inflammation. J Leukoc Biol 2010; 88:159-68. [PMID: 20360403 DOI: 10.1189/jlb.0609378] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Alveolar macrophages and BDMCs undergo sequential biochemical changes during the chronic inflammatory response to chemically induced lung carcinogenesis in mice. Herein, we examine two chronic lung inflammation models-repeated exposure to BHT and infection with Mycobacterium tuberculosis-to establish whether similar macrophage phenotype changes occur in non-neoplastic pulmonary disease. Exposure to BHT or M. tuberculosis results in pulmonary inflammation characterized by an influx of macrophages, followed by systemic effects on the BM and other organs. In both models, pulmonary IFN-gamma and IL-4 production coincided with altered polarization of alveolar macrophages. Soon after BHT administration or M. tuberculosis infection, IFN-gamma content in BALF increased, and BAL macrophages became classically (M1) polarized, as characterized by increased expression of iNOS. As inflammation progressed in both models, the amount of BALF IFN-gamma content and BAL macrophage iNOS expression decreased, and BALF IL-4 content and macrophage arginase I expression rose, indicating alternative/M2 polarization. Macrophages present in M. tuberculosis-induced granulomas remained M1-polarized, implying that these two pulmonary macrophage populations, alveolar and granuloma-associated, are exposed to different activating cytokines. BDMCs from BHT-treated mice displayed polarization profiles similar to alveolar macrophages, but BDMCs in M. tuberculosis-infected mice did not become polarized. Thus, only alveolar macrophages in these two models of chronic lung disease exhibit a similar progression of polarization changes; polarization of BDMCs was specific to BHT-induced pulmonary inflammation, and polarization of granuloma macrophages was specific to the M. tuberculosis infection.
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Affiliation(s)
- Elizabeth F Redente
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO 80045, USA
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Bauer AK, Dixon D, DeGraff LM, Cho HY, Walker CR, Malkinson AM, Kleeberger SR. Toll-like receptor 4 in butylated hydroxytoluene-induced mouse pulmonary inflammation and tumorigenesis. J Natl Cancer Inst 2005; 97:1778-81. [PMID: 16333033 DOI: 10.1093/jnci/dji403] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Because chronic pulmonary diseases predispose to lung neoplasia, the identification of the molecular mechanisms involved could provide novel preventive, diagnostic, and therapeutic strategies. Toll-like receptors (TLRs) transduce exogenous and endogenous signals into the production of inflammatory cytokines to coordinate adaptive immune responses. To determine the role of Tlr4 in chronic lung inflammation, we compared lung permeability, leukocyte infiltration, and nuclear factor kappa B (NFkappaB) and activator protein 1 (AP-1) DNA binding in butylated hydroxytoluene (BHT)-treated (four weekly injections of 125-200 mg/kg each) inbred mouse strains with functional Tlr4 (OuJ and BALB) and mutated Tlr4 (HeJ and BALB(Lps-d)). We also measured primary tumor formation in these mice after single-carcinogen injection (3-methylcholanthrene; 10 microg/kg), followed by BHT treatment (six weekly injections of 125-200 mg/kg each). Mice with functional Tlr4 had reduced lung permeability, leukocyte inflammation, and primary tumor formation (BALB(Lps-d), mean = 22.3 tumors/mouse, versus BALB, mean = 13.9 tumors/mouse, difference = 8.4 tumors/mouse, 95% confidence interval = 4.6 to 12.1 tumors/mouse; P = .025) compared with mice with mutated Tlr4. NFkappaB DNA binding activity was higher in OuJ than in HeJ mice; however, AP-1 activity was elevated in HeJ mice. To our knowledge, this is the first model to demonstrate a modulatory role for Tlr4 in chronic lung inflammation and tumorigenesis.
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Affiliation(s)
- Alison K Bauer
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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Bauer AK, Malkinson AM, Kleeberger SR. Susceptibility to neoplastic and non-neoplastic pulmonary diseases in mice: genetic similarities. Am J Physiol Lung Cell Mol Physiol 2004; 287:L685-703. [PMID: 15355860 DOI: 10.1152/ajplung.00223.2003] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chronic inflammation predisposes toward many types of cancer. Chronic bronchitis and asthma, for example, heighten the risk of lung cancer. Exactly which inflammatory mediators (e.g., oxidant species and growth factors) and lung wound repair processes (e.g., proangiogenic factors) enhance pulmonary neoplastic development is not clear. One approach to uncover the most relevant biochemical and physiological pathways is to identify genes underlying susceptibilities to inflammation and to cancer development at the same anatomic site. Mice develop lung adenocarcinomas similar in histology, molecular characteristics, and histogenesis to this most common human lung cancer subtype. Over two dozen loci, called Pas or pulmonary adenoma susceptibility, Par or pulmonary adenoma resistance, and Sluc or susceptibility to lung cancer genes, regulate differential lung tumor susceptibility among inbred mouse strains as assigned by QTL (quantitative trait locus) mapping. Chromosomal sites that determine responsiveness to proinflammatory pneumotoxicants such as ozone (O3), particulates, and hyperoxia have also been mapped in mice. For example, susceptibility QTLs have been identified on chromosomes 17 and 11 for O3-induced inflammation (Inf1, Inf2), O3-induced acute lung injury (Aliq3, Aliq1), and sulfate-associated particulates. Sites within the human and mouse genomes for asthma and COPD phenotypes have also been delineated. It is of great interest that several susceptibility loci for mouse lung neoplasia also contain susceptibility genes for toxicant-induced lung injury and inflammation and are homologous to several human asthma loci. These QTLs are described herein, candidate genes are suggested within these sites, and experimental evidence that inflammation enhances lung tumor development is provided.
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Affiliation(s)
- Alison K Bauer
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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Abstract
BHT is the recognized name in the cosmetics industry for butylated hydroxytoluene. BHT is used in a wide range of cosmetic formulations as an antioxidant at concentrations from 0.0002% to 0.5%. BHT does penetrate the skin, but the relatively low amount absorbed remains primarily in the skin. Oral studies demonstrate that BHT is metabolized. The major metabolites appear as the carboxylic acid of BHT and its glucuronide in urine. At acute doses of 0.5 to 1.0 g/kg, some renal and hepatic damage was seen in male rats. Short-term repeated exposure to comparable doses produced hepatic toxic effects in male and female rats. Subchronic feeding and intraperitoneal studies in rats with BHT at lower doses produced increased liver weight, and decreased activity of several hepatic enzymes. In addition to liver and kidney effects, BHT applied to the skin was associated with toxic effects in lung tissue. BHT was not a reproductive or developmental toxin in animals. BHT has been found to enhance and to inhibit the humoral immune response in animals. BHT itself was not generally considered genotoxic, although it did modify the genotoxicity of other agents. BHT has been associated with hepatocellular and pulmonary adenomas in animals, but was not considered carcinogenic and actually was associated with a decreased incidence of neoplasms. BHT has been shown to have tumor promotion effects, to be anticarcinogenic, and to have no effect on other carcinogenic agents, depending on the target organ, exposure parameters, the carcinogen, and the animal tested. Various mechanism studies suggested that BHT toxicity is related to an electrophillic metabolite. In a predictive clinical test, 100% BHT was a mild irritant and a moderate sensitizer. In provocative skin tests, BHT (in the 1% to 2% concentration range) produced positive reactions in a small number of patients. Clinical testing did not find any depigmentation associated with dermal exposure to BHT, although a few case reports of depigmentation were found. The Cosmetic Ingredient Review Expert Panel recognized that oral exposure to BHT was associated with toxic effects in some studies and was negative in others. BHT applied to the skin, however, appears to remain in the skin or pass through only slowly and does not produce systemic exposures to BHT or its metabolites seen with oral exposures. Although there were only limited studies that evaluated the effect of BHT on the skin, the available studies, along with the case literature, demonstrate no significant irritation, sensitization, or photosensitization. Recognizing the low concentration at which this ingredient is currently used in cosmetic formulations, it was concluded that BHT is safe as used in cosmetic formulations.
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Leonardis AD, Macciola V. Effectiveness of caffeic acid as an anti-oxidant for cod liver oil. Int J Food Sci Technol 2003. [DOI: 10.1046/j.1365-2621.2003.00707.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Umemura T, Kodama Y, Hioki K, Nomura T, Nishikawa A, Hirose M, Kurokawa Y. The mouse rasH2/BHT model as an in vivo rapid assay for lung carcinogens. Jpn J Cancer Res 2002; 93:861-6. [PMID: 12716462 PMCID: PMC5927112 DOI: 10.1111/j.1349-7006.2002.tb01330.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
We have demonstrated the utility of a 9-week in vivo two-stage assay for lung cancer initiating agents, using transgenic mice carrying the human prototype c-Ha-ras gene (rasH2 mice) and butylhydroxytoluene (BHT) as a potent lung promoter (rasH2/BHT model). In the present study, to ascertain appropriate conditions for BHT administration in this model, the effects of exposure on proliferation of alveolar type II cells in male rasH2 mice were examined. Additionally, use of BHT was validated for promotion of urethane (UR) carcinogenesis in male and female rasH2 mice. In a time-course study of a single intragastric administration of BHT at a dose of 400 mg/kg, increased bromodeoxyuridine-labeling index (LI) reached a maximum 3 days after treatment and was still observed after 7 days. In a dose-response study, effects were dose-dependent, the dose of 400 mg/kg causing eight-fold elevation as compared to the control. With repeated administration, whereas the LI was increased dramatically at first, effects gradually diminished with further exposure, and finally six BHT treatments failed to induce cell proliferation. In a two-stage model using UR as the initiator, although up to five consecutive doses of BHT were able to exert continued enhancing effects in terms of adenoma yield, no increment was evident with further treatments. The data overall indicate that a rasH2/BHT model with five weekly administrations of BHT at a dose of 400 mg/kg is most efficacious.
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Affiliation(s)
- Takashi Umemura
- Division of Pathology, Biological Safety Research Center, National Institute of Health Sciences, Setagaya-ku, Tokyo 158-8501, Japan.
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Malkinson AM, Radcliffe RA, Bauer AK. Quantitative trait locus mapping of susceptibilities to butylated hydroxytoluene-induced lung tumor promotion and pulmonary inflammation in CXB mice. Carcinogenesis 2002; 23:411-7. [PMID: 11895855 DOI: 10.1093/carcin/23.3.411] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have reported previously [Bauer,A.K. et al. (2001) Exp. Lung Res., 27, 197-216] that the 13 CXB recombinant inbred mouse strains derived from BALB/cByJ and C57BL/6J progenitors vary in their responsiveness to both lung tumor promotion and pulmonary inflammation induced by chronic administration of butylated hydroxytoluene (BHT). Herein we have applied these data, along with markers known to be polymorphic among these strains, to conduct linkage analysis of these susceptibilities. This enabled us to assign provisional quantitative trait loci (QTL) that govern these strain variations in susceptibility as a genetic approach to assessing the influence of inflammation on tumorigenesis. A Chr 15 (39.1-55.6 cM) QTL regulated susceptibility to two-stage carcinogenesis, a protocol in which chronic BHT exposure followed a single urethane injection; a similar QTL on Chr 15 (46.7-61.7 cM) influenced BHT induction of cyclooxygenase-2 (COX-2) expression. A Chr 18 (37-41 cM) QTL modulated both the number of lung tumors induced by 3-methylcholanthrene (MCA) injection with subsequent treatment with BHT as well as BHT-induced ingress of macrophages into airways. Other chromosomal sites that affected either the degree of BHT-elicited macrophage infiltration, Chr 9 (48-61 cM), or COX-2 induction, Chr 10 (59-65 cM), were reported to influence susceptibility to lung tumorigenesis in other strains. The fact that common chromosomal locations regulate both inflammation and carcinogenesis suggests a pathogenic role of inflammatory mediators in tumor development that may be exploited for chemoprevention of lung cancer.
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Affiliation(s)
- Alvin M Malkinson
- Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262, USA.
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Bauer AK, Dwyer-Nield LD, Hankin JA, Murphy RC, Malkinson AM. The lung tumor promoter, butylated hydroxytoluene (BHT), causes chronic inflammation in promotion-sensitive BALB/cByJ mice but not in promotion-resistant CXB4 mice. Toxicology 2001; 169:1-15. [PMID: 11696405 DOI: 10.1016/s0300-483x(01)00475-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An inflammatory response accompanies the reversible pneumotoxicity caused by butylated hydroxytoluene (BHT) administration to mice. Lung tumor formation is promoted by BHT administration following an initiating agent in BALB/cByJ mice, but not in CXB4 mice. To assess the contribution of inflammation to this differential susceptibility, we quantitatively characterized inflammation after one 150 mg/kg body weight, followed by three weekly 200 mg/kg ip injections of BHT into male mice of both strains. This examination included inflammatory cell infiltrate and protein contents in bronchoalveolar lavage (BAL) fluid, cyclooxygenase (COX)-1 and COX-2 expression in lung extracts, and PGE(2) and PGI(2) production by isolated bronchiolar Clara cells. BAL macrophage and lymphocyte numbers increased in BALB mice (P<0.0007 and 0.02, respectively), as did BAL protein content (P<0.05), COX-1 and COX-2 expression (P<0.05 for each), and PGI(2) production (P<0.05); conversely, these indices were not perturbed by BHT in CXB4 mice. BALB mice fed aspirin (400 mg/kg of chow) for two weeks prior to BHT treatment had reduced inflammatory cell infiltration. Our results support a hypothesis that resistance to BHT-induced inflammation in CXB4 mice accounts, at least in part, for the lack of effect of BHT on lung tumor multiplicity in this strain.
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Affiliation(s)
- A K Bauer
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver, CO 80262, USA
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Malkinson AM. Primary lung tumors in mice as an aid for understanding, preventing, and treating human adenocarcinoma of the lung. Lung Cancer 2001; 32:265-79. [PMID: 11390008 DOI: 10.1016/s0169-5002(00)00232-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Primary lung tumors in mice have morphologic, histogenic, and molecular features similar to human lung adenocarcinoma, and in particular, the bronchiolo-alveolar carcinoma subtype. Because of this, and because of the genetic homology between man and mouse and the ease of genetic manipulations in mice, this model system is receiving intense research attention. This review is intended to be informative to clinical investigators, and describes features of this model, how it is being used for translational research, and points out additional avenues of study that could have practical benefits, such as application for identifying novel therapeutic strategies.
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Affiliation(s)
- A M Malkinson
- Department of Pharmaceutical Sciences and University of Colorado Cancer Center, University of Colorado Health Sciences Center, Denver, CO 80262, USA.
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Dwyer-Nield LD, Paigen B, Porter SE, Malkinson AM. Quantitative trait locus mapping of genes regulating pulmonary PKC activity and PKC-alpha content. Am J Physiol Lung Cell Mol Physiol 2000; 279:L326-32. [PMID: 10926556 DOI: 10.1152/ajplung.2000.279.2.l326] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Strain A/J mice, which are predisposed to experimentally induced asthma and adenocarcinoma, have the lowest pulmonary protein kinase (PK) C activity and content among 22 inbred mouse strains. PKC in neonatal A/J mice is similar to that in other strains, so this difference reflects strain-dependent postnatal regulation. PKC activity is 60% higher in C57BL/6J (B6) than in A/J lungs, and the protein and mRNA concentrations of PKC-alpha, the major pulmonary PKC isozyme, are two- to threefold higher in B6 mice. These differences result from more than a single gene as assessed in F(1), F(2), and backcross progeny of B6 and A/J parents. Quantitative trait locus (QTL) analysis of 23 AxB and BxA recombinant inbred strains derived from B6 and A/J progenitors indicates a major locus regulating lung PKC-alpha content that maps near the Pkcalpha structural gene on chromosome 11 (D11MIT333; likelihood ratio statistic = 12.5) and a major locus controlling PKC activity that maps on chromosome 3 (D3MIT19; likelihood ratio statistic = 15.4). The chromosome 11 QTL responsible for low PKC-alpha content falls within QTLs for susceptibilities to lung tumorigenesis and ozone-induced toxicity.
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Affiliation(s)
- L D Dwyer-Nield
- Department of Pharmaceutical Sciences and University of Colorado Cancer Center, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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Blaxall BC, Dwyer-Nield LD, Bauer AK, Bohlmeyer TJ, Malkinson AM, Port JD. Differential Expression and Localization of the mRNA Binding Proteins, AU-Rich Element mRNA Binding Protein (AUF1) and Hu Antigen R (HuR), in Neoplastic Lung Tissue. Mol Carcinog 2000. [DOI: 10.1002/1098-2744(200006)28:2<76::aid-mc3>3.0.co;2-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gressani KM, Leone-Kabler S, O'Sullivan MG, Case LD, Malkinson AM, Miller MS. Strain-dependent lung tumor formation in mice transplacentally exposed to 3-methylcholanthrene and post-natally exposed to butylated hydroxytoluene. Carcinogenesis 1999; 20:2159-65. [PMID: 10545420 DOI: 10.1093/carcin/20.11.2159] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The carcinogenic effects of in utero exposure to 3-methylcholanthrene (MC) have been demonstrated in the tumor-resistant C57BL/6 (B6) and DBA (D2) strains of mice. In this study, we determined the effects of in utero exposure to MC in BALB/c mice, a strain which demonstrates greater susceptibility to lung tumor induction, and compared our findings with those previously found in [D2xB6D2F(1)]F(2) mice. In addition, we assessed the molecular pathogenesis of the chemically induced tumors and examined the effects of the putative lung tumor promoter butylated hydroxytoluene (BHT) in BALB/c mice. BALB/c mice were treated on day 17 of gestation with 5, 15 or 45 mg/kg MC and 6 weeks after birth with BHT for 6 consecutive weeks. Mice were killed at 6 months of age. Ki-ras, p16Ink4a and p19ARF gene loci were amplified from paraffin-embedded lung tumor tissue and screened for the presence of point mutations via allele-specific oligonucleotide hybridization and single strand conformation polymorphism (SSCP) analyses. Ki-ras point mutations were found in 56% (20/36) of BALB/c lung tumors, with 33% (2/6) of the hyperplasias, 58% (10/19) of the adenomas and 73% (8/11) of the carcinomas exhibiting point mutations at this gene locus. Similar incidences of Ki-ras mutations were previously found following transplacental exposure of [D2xB6D2F(1)]F(2) mice to MC and treatment of adult A/J mice with urethane. Interestingly, a strain-dependent difference was observed in the mutational spectrum. Sixty-two and 38% of the lung lesions in BALB/c mice exhibited G-->C and G-->T transversions, respectively, in contrast to the 13 and 84% incidences previously observed in [D2xB6D2F(1)]F(2) mice. SSCP analysis of the tumor suppressor gene p16Ink4a showed a 6% incidence of point mutations, consistent with that found in [D2xB6D2F(1)]F(2) mice. No mutations were found in exon 1beta of the p19ARF gene of either strain. BHT, a lung tumor promoter in adult mice, had no statistically significant effects on either tumor incidence, tumor multiplicity or the mutational spectrum produced in the Ki-ras gene by in utero MC treatment. However, though not significant, there was an observable trend in increased tumor multiplicity in mice co-treated with BHT. These data demonstrate the transplacental carcinogenic effect of MC in BALB/c mice and show that mutagenic damage to Ki-ras is a critical early event mediating murine lung tumorigenesis in both the tumor-sensitive and tumor-resistant strains. Unlike what occurs when adult BALB/c mice are treated with MC, BHT does not appear to significantly promote the formation of lung tumors following transplacental exposure to MC, possibly due to the rapid growth and cell proliferation in the developing organism. Strain-dependent differences in the Ki-ras mutational spectrum may be associated with their differential susceptibility to lung tumor initiation.
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Affiliation(s)
- K M Gressani
- Department of Physiology and Pharmacology, Department of Cancer Biology and Department of Public Health Sciences, Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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Rice PL, Porter SE, Koski KM, Ramakrishna G, Chen A, Schrump D, Kazlauskas A, Malkinson AM. Reduced receptor expression for platelet-derived growth factor and epidermal growth factor in dividing mouse lung epithelial cells. Mol Carcinog 1999; 25:285-94. [PMID: 10449035 DOI: 10.1002/(sici)1098-2744(199908)25:4<285::aid-mc7>3.0.co;2-f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The roles of growth factors in mouse lung neoplasia were investigated by examining receptors for platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) in epithelial cell lines. Whereas nontumorigenic lung cells expressed mRNA and protein for PDGF receptor (PDGFR)-alpha, PDGFR-beta, and EGF receptor (EGFR), five of six neoplastic lines did not. Because this exceptional tumorigenic cell line grows slowly, we hypothesized that receptor levels increased with cell stasis. To test this hypothesis, serum concentrations were manipulated, and log-phase and post-confluent cells were compared. Consistent with our hypothesis, PDGFR-alpha and EGFR contents, but not PDGFR-beta contents, increased at stasis. Ki-ras mutation initiates lung tumorigenesis in mice, but activation of Ki-ras did not affect receptor expression. This was determined both by transfecting nontumorigenic cells with activated Ki-ras and neoplastic cells with a Ki-ras antisense construct and by diminishing Ki-ras activation by using a farnesyltransferase inhibitor. Stasis-associated upregulation of growth-factor receptor expression suggests a function in lung cell differentiation that is abrogated during neoplastic growth.
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Affiliation(s)
- P L Rice
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Health Sciences Center, Denver 80262, USA
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Dwyer-Nield LD, Thompson JA, Peljak G, Squier MK, Barker TD, Parkinson A, Cohen JJ, Dinsdale D, Malkinson AM. Selective induction of apoptosis in mouse and human lung epithelial cell lines by the tert-butyl hydroxylated metabolite of butylated hydroxytoluene: a proposed role in tumor promotion. Toxicology 1998; 130:115-27. [PMID: 9865479 DOI: 10.1016/s0300-483x(98)00102-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Butylated hydroxytoluene (BHT) causes lung injury in mice and promotes tumor formation. Hydroxylation of a tert-butyl group on BHT to yield the metabolite, 6-tert-butyl-2-[2'-(2'-hydroxymethyl)-propyl]-4-methylphenol (BHTOH), may be required. BHTOH is more potent than BHT on an equimolar basis in causing lung damage, enhancing lung tumor development, killing isolated bronchiolar non-ciliated Clara cells, and inhibiting lung epithelial gap junctional intercellular communication. One mechanism proposed for tumor promoting agents is selective cytotoxicity; killing normal cells allows uninhibited clonal expansion of neighboring initiated cells. We compared the abilities of BHT, BHTOH, and other BHT metabolites to kill non-tumorigenic and tumorigenic mouse and human lung cell lines, and examined the contribution of apoptosis to this cytotoxicity. These cells lack the cytochrome P450 2B isozyme necessary for converting BHT to BHTOH. BHTOH and 4-hydroperoxy-4-methyl-2,6-di-tert-butyl-2,5-cyclohex-adienone+ ++ (BHTOOH) were most toxic, BHT and 2,6-di-tert-butyl-1,4-benzoquinone (BHTQu) were less potent, and 4-methyl BHT metabolites that are not pneumotoxic were ineffective. BHTOH most strongly induced apoptosis, based on nuclear condensation and transmission electron microscopy. Non-tumorigenic cells were as susceptible to cell death as the neoplastic cell lines when apoptosis and necrosis are not distinguished, but more sensitive to BHTOH-induced apoptosis. An apoptotic mechanism may underlie the lung tumor promoting actions of BHTOH.
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Affiliation(s)
- L D Dwyer-Nield
- Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, Denver 80262, USA
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Malkinson AM, Dwyer-Nield LD, Rice PL, Dinsdale D. Mouse lung epithelial cell lines--tools for the study of differentiation and the neoplastic phenotype. Toxicology 1997; 123:53-100. [PMID: 9347924 DOI: 10.1016/s0300-483x(97)00108-x] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Several dozen lung epithelial cell lines have been established in culture over the past 20 years from normal lung explants and their spontaneous transformants, and from lung tumors that arose spontaneously or were induced with chemicals, viruses, or oncogenic transgenes. To provide information from which to choose appropriate lines for investigating problems in lung cell biology and pulmonary neoplasia, this review describes the origins of these lines and some of their characteristics. These include growth, morphology, tumorigenicity, ability to metastasize, xenobiotic metabolism, mutational status, signal transducing activities, cytogenetics, ability to form domes, and electric conductance. In addition to collecting this information in a single place for the first time, we describe previously unpublished apoptosis features of some of these lines. An increasing number of investigations are beginning to use these lines and this review contains references into 1997.
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Affiliation(s)
- A M Malkinson
- Department of Pharmaceutical Sciences, Colorado Cancer Center, University of Colorado Health Sciences Center, Denver 80262, USA
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Sun B, Fukuhara M, Kinoshita T, Kimura M, Ushio F. Differential induction of isozymes of drug-metabolizing enzymes by butylated hydroxytoluene in mice and Chinese hamsters. Food Chem Toxicol 1996; 34:595-601. [PMID: 8761352 DOI: 10.1016/0278-6915(96)00020-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Induction of isozymes of drug-metabolizing enzymes by butylated hydroxytoluene (BHT) was studied in the male ddY mouse and Chinese hamster. In mice given 0.05 and 0.15% BHT in the diet for 14 days cytochrome P-450 contents and the activities of uridine diphosphate-glucuronyl transferase (UDP-GT) and pentoxyresorufin O-dealkylase were markedly increased, while in those fed 0.15% BHT testosterone 6 alpha-, 16 alpha- and 16 beta-hydroxylases were greatly increased, which indicated induction of cytochrome P-450 isozymes of the CYP2B family. Western blot analysis also showed an increased level of the isozyme immunorelated to rat CYP2B2 by BHT feeding. The activities of aryl hydrocarbon hydroxylase, ethoxycoumarin O-deethylase (ECOD), erythromycin N-demethylase and glutathione S-transferase (GST) remained unchanged. In Chinese hamsters given 0.05 and 0.15% BHT in the diet for 14 days activities of ECOD and GST were induced, but cytochrome P-450 contents and the activities of other enzymes were unaffected. Testosterone 15 alpha-hydroxylase was induced in hamsters fed 0.15% BHT. These findings suggested that BHT administration in the hamster induced CYP2A2-type isozyme, which was confirmed by Western blot analysis. BHT treatment enhanced activation of benzo[a] pyrene (B[a]P) as determined by the mutagenicity test, especially in Chinese hamsters. The results suggest that BHT treatment induces specific isozymes of drug-metabolizing enzymes and might modify the expression of toxicities of other chemicals.
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Affiliation(s)
- B Sun
- Department of Pharmaceutical Sciences, National Institute of Public Health, Tokyo, Japan
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Miller AC, Dwyer-Nield LD, Malkinson AM. Very early changes in pulmonary protein kinase C-alpha and calpain II contents following injection of butylated hydroxytoluene (BHT) into mice. Toxicology 1995; 97:141-9. [PMID: 7716780 DOI: 10.1016/0300-483x(94)02943-o] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Butylated hydroxytoluene (BHT)-induced lung damage in mice is an excellent model system for studying mechanisms of chemically-induced, reversible alveolar injury. Changes in the pulmonary contents of protein kinase C (PKC) and the calcium-dependent protease, calpain, were previously noted during the repair phase following BHT-induced pneumotoxicity. Calpain is believed to initiate PKC down-regulation. PKC-alpha is the major PKC isozyme and calpain II the major calpain isozyme in mouse lung. We have now studied the time course of these enzymatic changes in detail. Pulmonary PKC-alpha concentrations decreased as early as 45 min after an i.p. injection of 200 mg/kg BHT. Calpain II levels rose within the first 40 min after BHT injection, and then declined below control levels. The rapidity of these changes implies a role of these enzymes in mediating the onset of injury. Lung damage and repair, as estimated by measuring the lung weight/body weight ratio, is maximal 6 days after administration of this dose of BHT. The extent of the decreased PKC-alpha and calpain II concentrations at this time was linearly related to the estimated degree of injury based on increased lung weight. This correlation suggests the value of monitoring these enzymes as putative early biomarkers of alveolar injury.
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Affiliation(s)
- A C Miller
- Colorado Cancer Center, School of Pharmacy, University of Colorado, Denver 80262, USA
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