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Jatko JT, Darling CL, Kellett MP, Bain LJ. Arsenic exposure in drinking water reduces Lgr5 and secretory cell marker gene expression in mouse intestines. Toxicol Appl Pharmacol 2021; 422:115561. [PMID: 33957193 DOI: 10.1016/j.taap.2021.115561] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 02/28/2021] [Accepted: 04/30/2021] [Indexed: 12/12/2022]
Abstract
Arsenic is a global health concern that causes toxicity through ingestion of contaminated water and food. In vitro studies suggest that arsenic reduces stem and progenitor cell differentiation. Thus, this study determined if arsenic disrupted intestinal stem cell (ISC) differentiation, thereby altering the number, location, and/or function of intestinal epithelial cells. Adult male C57BL/6 mice were exposed to 0 or 100 ppb sodium arsenite (AsIII) through drinking water for 5 weeks. Duodenal sections were collected to assess changes in morphology, proliferation, and cell types. qPCR analysis revealed a 40% reduction in Lgr5 transcripts, an ISC marker, in the arsenic-exposed mice, although there were no changes in the protein expression of Olfm4. Secretory cell-specific transcript markers of Paneth (Defa1), Goblet (Tff3), and secretory transit amplifying (Math1) cells were reduced by 51%, 44%, and 30% respectively, in the arsenic-exposed mice, indicating significant impacts on the Wnt-dependent differentiation pathway. Further, protein levels of phosphorylated β-catenin were reduced in the arsenic-exposed mice, which increased the expression of Wnt-dependent transcripts CD44 and c-myc. PCA analysis, followed by MANOVA and regression analyses, revealed significant changes and correlations between Lgr5 and the transit amplifying (TA) cell markers Math1 and Hes1, which are in the secretory cell pathway. Similar comparisons between Math1 and Defa1 show that terminal differentiation into Paneth cells is also reduced in the arsenic-exposed mice. The data suggests that ISCs are not lost following arsenic exposure, but rather, specific Wnt-dependent progenitor cell formation and terminal differentiation in the small intestine is reduced.
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Affiliation(s)
- Jordan T Jatko
- Environmental Toxicology Graduate Program, Clemson University, 132 Long Hall, Clemson, SC 29634, USA
| | - Caitlin L Darling
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634, USA
| | - Michael P Kellett
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634, USA
| | - Lisa J Bain
- Environmental Toxicology Graduate Program, Clemson University, 132 Long Hall, Clemson, SC 29634, USA; Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634, USA.
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2
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Hong BV, Lee JH, Rice RH. Off-target effects of protein tyrosine phosphatase inhibitors on oncostatin M-treated human epidermal keratinocytes: the phosphatase targeting STAT1 remains unknown. PeerJ 2020; 8:e9504. [PMID: 32864202 PMCID: PMC7430265 DOI: 10.7717/peerj.9504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 06/17/2020] [Indexed: 12/11/2022] Open
Abstract
Cytokine signaling in the epidermis has an important role in maintaining barrier function and is perturbed in pathological conditions. Environmental exposures, such as to metal compounds, are of interest for their potential contribution to skin disease. Present work explores the possibility that vanadate is a more effective protein tyrosine phosphatase inhibitor in human keratinocytes than previously observed in fibroblasts. It focuses on the state of phosphorylation of signal transducer and activator of transcription 1 (STAT1) on tyrosine 701 upon treatment of cultured human keratinocytes with the cytokine oncostatin M, a cutaneous inflammatory mediator that is highly effective in suppressing several differentiation markers and in preserving proliferative potential of keratinocytes. Exposure to sodium vanadate in the medium greatly prolonged the phosphorylation of STAT1, but only at high concentration (>30 µM). Inhibitors of protein tyrosine phosphatases known to dephosphorylate STAT1 (SHP2, TCPTP, PTP1B) were ineffective in mimicking the action of vanadate. The irreversible protein tyrosine phosphatase inhibitor phenyl vinyl sulfonate alone induced STAT1 phosphorylation and appeared to induce its limited cleavage. It also inhibited cross-linked envelope formation, a characteristic step of keratinocyte terminal differentiation, likely due to its reaction with the active site cysteine of keratinocyte transglutaminase. Thus, the key protein tyrosine phosphatase responsible for STAT1 dephosphorylation remains to be identified, and an off-target effect of a potential inhibitor was revealed.
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Affiliation(s)
- Brian V Hong
- Department of Environmental Toxicology and Forensic Science Program, University of California, Davis, CA, United States of America
| | - Ji H Lee
- Department of Environmental Toxicology and Forensic Science Program, University of California, Davis, CA, United States of America
| | - Robert H Rice
- Department of Environmental Toxicology and Forensic Science Program, University of California, Davis, CA, United States of America
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3
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Cheikhi A, Anguiano T, Lasak J, Qian B, Sahu A, Mimiya H, Cohen CC, Wipf P, Ambrosio F, Barchowsky A. Arsenic Stimulates Myoblast Mitochondrial Epidermal Growth Factor Receptor to Impair Myogenesis. Toxicol Sci 2020; 176:162-174. [PMID: 32159786 PMCID: PMC7357174 DOI: 10.1093/toxsci/kfaa031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Arsenic exposure impairs muscle metabolism, maintenance, progenitor cell differentiation, and regeneration following acute injury. Low to moderate arsenic exposures target muscle fiber and progenitor cell mitochondria to epigenetically decrease muscle quality and regeneration. However, the mechanisms for how low levels of arsenic signal for prolonged mitochondrial dysfunction are not known. In this study, arsenic attenuated murine C2C12 myoblasts differentiation and resulted in abnormal undifferentiated myoblast proliferation. Arsenic prolonged ligand-independent phosphorylation of mitochondrially localized epidermal growth factor receptor (EGFR), a major driver of proliferation. Treating cells with a selective EGFR kinase inhibitor, AG-1478, prevented arsenic inhibition of myoblast differentiation. AG-1478 decreased arsenic-induced colocalization of pY845EGFR with mitochondrial cytochrome C oxidase subunit II, as well as arsenic-enhanced mitochondrial membrane potential, reactive oxygen species generation, and cell cycling. All of the arsenic effects on mitochondrial signaling and cell fate were mitigated or reversed by addition of mitochondrially targeted agents that restored mitochondrial integrity and function. Thus, arsenic-driven pathogenesis in skeletal muscle requires sustained mitochondrial EGFR activation that promotes progenitor cell cycling and proliferation at the detriment of proper differentiation. Collectively, these findings suggest that the arsenic-activated mitochondrial EGFR pathway drives pathogenic signaling for impaired myoblast metabolism and function.
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Affiliation(s)
- Amin Cheikhi
- Division of Geriatric Medicine, Department of Medicine
- Department of Environmental and Occupational Health
- Department of Physical Medicine and Rehabilitation
| | | | - Jane Lasak
- Department of Physical Medicine and Rehabilitation
| | - Baoli Qian
- Department of Environmental and Occupational Health
| | - Amrita Sahu
- Department of Physical Medicine and Rehabilitation
| | | | | | | | - Fabrisia Ambrosio
- Department of Environmental and Occupational Health
- Department of Physical Medicine and Rehabilitation
- McGowan Institute for Regenerative Medicine
- Department of Bioengineering
| | - Aaron Barchowsky
- Department of Environmental and Occupational Health
- Department of Bioengineering
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
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4
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Kim C, States JC, Ceresa BP. Chronic and acute arsenic exposure enhance EGFR expression via distinct molecular mechanisms. Toxicol In Vitro 2020; 67:104925. [PMID: 32599262 DOI: 10.1016/j.tiv.2020.104925] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/02/2020] [Accepted: 06/22/2020] [Indexed: 01/06/2023]
Abstract
The impacts of acute arsenic exposure (i.e. vomiting, diarrhea, and renal failure) are distinct from those brought about by sustained, low level exposure from environmental sources or drinking of contaminated well water. Chronic arsenic exposure is a risk factor for the development of pulmonary diseases, including lung cancer. How arsenic exposure leads to pulmonary disease is not fully understood. Both acute versus chronic arsenic exposure increase EGFR expression, but do so via distinct molecular mechanisms. BEAS-2B cells were exposed to either acute sodium arsenite (5 μM for 24 h) or chronic sodium arsenite (100 nM for 24 weeks). Cells treated with acute arsenic exhibited a decrease in viability, changes in morphology, and increased mRNA level of BTC. In contrast, during 24 weeks of arsenic exposure, the cells had increased EGFR expression and activity, and increased mRNA and protein levels of TGFα. Further, chronic arsenic treatment caused an increase in cell migration in the absence of exogenous ligand. Elevated TGFα and EGFR expression are features of many non-small cell lung cancers. We propose that lung epithelial cells chronically exposed to low level arsenic increases EGFR signaling via TGFα production to enhance ligand-independent cell migration.
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Affiliation(s)
- Christine Kim
- Department of Pharmacology and Toxicology, University of Louisville, USA
| | | | - Brian P Ceresa
- Department of Pharmacology and Toxicology, University of Louisville, USA.
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5
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Li S, Ren Q. Effects of Arsenic on wnt/β-catenin Signaling Pathway: A Systematic Review and Meta-analysis. Chem Res Toxicol 2020; 33:1458-1467. [PMID: 32307979 DOI: 10.1021/acs.chemrestox.0c00019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We aimed to systematically evaluate the regulatory effect of arsenic on wnt/β-catenin signaling pathway and to provide theoretical basis for revealing the mechanism of the relationship between arsenic and cell proliferation. The meta-analysis was carried out using Revman5.2 and Stata13.0 to describe the differences between groups with standard mean difference. We found in normal cells that the levels of wnt3a, β-catenin, glycogen synthase kinase-3β phosphorylated at serine 9 (p-GSK-3β(Ser9)), cyclinD1, proto-oncogene c-myc, and vascular endothelial growth factor (VEGF) in the arsenic intervention group were higher than those in the control group, and the level of glycogen synthase kinase-3β (GSK-3β) was lower than that in the control group (P < 0.05, respectively). Subgroup analysis showed that for a long time period (>24 h), the level of β-catenin in the arsenic intervention group was higher than that in the control group, and the level of GSK-3β of the same long-time period (>24 h) with low-dose (≤5 μM) intervention was lower than those in the control group (P < 0.05, respectively). In cancer cells, the levels of β-catenin, cyclinD1, c-myc, and VEGF in the arsenic intervention group were lower than those in the control group, while the level of GSK-3β in the arsenic intervention group was higher than that in the control group (P < 0.05, respectively). Subgroup analysis showed that the levels of β-catenin, cyclinD1, and c-myc in the high-dose (>5 μM) arsenic intervention group were lower than those in the control group, and the levels of β-catenin and cyclinD1 in the high-dose (>5 μM) arsenic intervention group were lower than those in the low-dose (≤5 μM) arsenic intervention group (P < 0.05, respectively). In addition, the regulation of arsenic on β-catenin was dose-dependent in the range of arsenic concentration from 0 to 7.5 μM. This study revealed that arsenic could upregulate wnt/β-catenin signaling pathway in normal cells and downregulate it in cancer cells, and its effect was affected by time and dose.
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Affiliation(s)
- Shugang Li
- Department of Child, Adolescent Health and Maternal Health, School of Public Health, Capital Medical University, Beijing 100069, China
| | - Qingxin Ren
- Department of Public Health, College of Medicine, Shihezi University, Shihezi 832000, Xinjiang China
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6
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Phillips MA, Cánovas A, Rea MA, Islas-Trejo A, Medrano JF, Durbin-Johnson B, Rocke DM, Rice RH. Deducing signaling pathways from parallel actions of arsenite and antimonite in human epidermal keratinocytes. Sci Rep 2020; 10:2890. [PMID: 32076005 PMCID: PMC7031270 DOI: 10.1038/s41598-020-59577-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/29/2020] [Indexed: 11/09/2022] Open
Abstract
Inorganic arsenic oxides have been identified as carcinogens in several human tissues, including epidermis. Due to the chemical similarity between trivalent inorganic arsenic (arsenite) and antimony (antimonite), we hypothesized that common intracellular targets lead to similarities in cellular responses. Indeed, transcriptional and proteomic profiling revealed remarkable similarities in differentially expressed genes and proteins resulting from exposure of cultured human epidermal keratinocytes to arsenite and antimonite in contrast to comparisons of arsenite with other metal compounds. These data were analyzed to predict upstream regulators and affected signaling pathways following arsenite and antimonite treatments. A majority of the top findings in each category were identical after treatment with either compound. Inspection of the predicted upstream regulators led to previously unsuspected roles for oncostatin M, corticosteroids and ephrins in mediating cellular response. The influence of these predicted mediators was then experimentally verified. Together with predictions of transcription factor effects more generally, the analysis has led to model signaling networks largely accounting for arsenite and antimonite action. The striking parallels between responses to arsenite and antimonite indicate the skin carcinogenic risk of exposure to antimonite merits close scrutiny.
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Affiliation(s)
- Marjorie A Phillips
- Department of Environmental Toxicology, University of California, Davis, CA, USA
| | - Angela Cánovas
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Miguel A Rea
- Department of Chemistry, Universidad Autónoma Querétaro, Querétaro, Mexico
| | - Alma Islas-Trejo
- Department of Animal Science, University of California, Davis, CA, USA
| | - Juan F Medrano
- Department of Animal Science, University of California, Davis, CA, USA
| | - Blythe Durbin-Johnson
- Division of Biostatistics, Department of Public Health Sciences, Clinical and Translational Science Center Biostatistics Core, University of California, Davis, CA, USA
| | - David M Rocke
- Division of Biostatistics, Department of Public Health Sciences, Clinical and Translational Science Center Biostatistics Core, University of California, Davis, CA, USA
| | - Robert H Rice
- Department of Environmental Toxicology, University of California, Davis, CA, USA.
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Wang Z, Yang C. Metal carcinogen exposure induces cancer stem cell-like property through epigenetic reprograming: A novel mechanism of metal carcinogenesis. Semin Cancer Biol 2019; 57:95-104. [PMID: 30641125 PMCID: PMC6625953 DOI: 10.1016/j.semcancer.2019.01.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 12/13/2022]
Abstract
Arsenic, cadmium, nickel and hexavalent chromium are among the most common environmental pollutants and potent carcinogens. Chronic exposure to these metals causes various types of cancer in humans, representing a significant environmental health issue. Although under active investigation, the mechanisms of metal carcinogenesis have not been clearly defined. One common feature of these metal carcinogens is that they are all able to cause various epigenetic dysregulations, which are believed to play important roles in their carcinogenicity. However, how metal carcinogen-caused epigenetic dysregulation contributes to metal carcinogenesis remains largely unknown. The evolution of cancer stem cell (CSC) theory has opened exciting new avenues for studying the mechanism of metal carcinogenesis. Increasing evidence indicates that chronic metal carcinogen exposure produces CSC-like cells through dysregulated epigenetic mechanisms. This review will first provide some brief introductions about CSC, epigenetics and epigenetic regulation of CSCs; then summarize progresses in recent studies on metal carcinogen-induced CSC-like property through epigenetic reprograming as a novel mechanism of metal carcinogenesis. Some perspectives for future studies in this field are also presented.
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Affiliation(s)
- Zhishan Wang
- Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, Lexington, KY, United States.
| | - Chengfeng Yang
- Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, Lexington, KY, United States; Center for Research on Environment Disease, College of Medicine, University of Kentucky, Lexington, KY, United States.
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8
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Cutaneous Malignancy due to Arsenicosis in Bangladesh: 12-Year Study in Tertiary Level Hospital. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4678362. [PMID: 30643806 PMCID: PMC6311317 DOI: 10.1155/2018/4678362] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 12/03/2018] [Indexed: 12/12/2022]
Abstract
Bangladesh is grappling with the largest mass poisoning of a population in the world due to contamination of drinking water with naturally occurring inorganic arsenic. It is estimated that 75 million people of 59 (out of 64) districts are at risk of drinking contaminated water with arsenic above 50μg/L. Long term exposure to arsenic causes cancers, including skin, lung, and bladder. This is a randomized prospective study to see the prevalence of skin cancer from arsenic affected area of Bangladesh, as well as their variation by geographical area, age, gender, location on the body, and socioeconomic conditions, in outpatient department of plastic surgery unit of Bangabandhu Sheikh Mujib Medical University (BSMMU). A total of 960 patients with skin cancers comprised of 528 males and 432 females were selected for the study from January 2004 to December 2015. In this 12-year study, we found squamous cell carcinoma, basal cell carcinoma, melanoma, and Merkel cell carcinoma to be associated with the ingestion of arsenic contaminated ground water. This is a reflection of a small part of the total national scenario of devastating result of arsenic mediated cancer in terms of skin malignancy. This study will help the future researchers who are contemplating to work on arsenic induced health problem.
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Stannard L, Doak SH, Doherty A, Jenkins GJ. Is Nickel Chloride really a Non-Genotoxic Carcinogen? Basic Clin Pharmacol Toxicol 2017; 121 Suppl 3:10-15. [PMID: 27748567 DOI: 10.1111/bcpt.12689] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/13/2016] [Indexed: 12/16/2022]
Abstract
Human beings are exposed to carcinogens through air, water, food and tobacco smoke. Nickel chloride (NiCl2 ) is a toxic and carcinogenic environmental and occupational pollutant, which was previously classified as a non-genotoxic carcinogen and thought to not directly alter the DNA. Non-genotoxic carcinogens such as NiCl2 are difficult to detect in vitro; hence, a heavy reliance on animal studies exists. NiCl2 has previously been classified as a non-genotoxic carcinogen (NGTC); however, after studying the effect of NiCl2 on many mechanistic end-points, it has become clear that NiCl2 behaves more like a genotoxic carcinogen. The induction of reactive oxygen species (ROS) after treatment with NiCl2 along with positive micronuclei results from a preliminary 5-day chronic dose micronucleus study further supports that NiCl2 has been misclassified as a NGTC. It is possible that NiCl2 causes indirect DNA damage by the production of ROS and requires a longer, chronic exposure, which is more similar to that of human exposure. The focus of this MiniReview is on research into the molecular mechanisms of nickel-induced carcinogenicity and potential genotoxicity, with a focus on one of the salts of greatest commercial importance, nickel chloride.
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Affiliation(s)
- Leanne Stannard
- In Vitro Toxicology Group, Institute of Life Science, Swansea University Medical School, Swansea University, Swansea, Wales, UK
| | - Shareen H Doak
- In Vitro Toxicology Group, Institute of Life Science, Swansea University Medical School, Swansea University, Swansea, Wales, UK
| | - Ann Doherty
- Genetic Toxicology, Drug Safety and Metabolism, AstraZeneca R&D, Cambridge, UK
| | - Gareth J Jenkins
- In Vitro Toxicology Group, Institute of Life Science, Swansea University Medical School, Swansea University, Swansea, Wales, UK
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Wang L, Fan J, Hitron JA, Son YO, Wise JTF, Roy RV, Kim D, Dai J, Pratheeshkumar P, Zhang Z, Shi X. Cancer Stem-Like Cells Accumulated in Nickel-Induced Malignant Transformation. Toxicol Sci 2016; 151:376-87. [PMID: 26962057 DOI: 10.1093/toxsci/kfw044] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nickel compounds are known as human carcinogens. Chronic environmental exposure to nickel is a worldwide health concern. Although the mechanisms of nickel-induced carcinogenesis are not well understood, recent studies suggest that stem cells/cancer stem cells are likely important targets. This study examines the role of cancer stem cells in nickel-induced cell transformation. The nontransformed human bronchial epithelial cell line (Beas-2B) was chronically exposed to nickel chloride for 12 months to induce cell transformation. Nickel induced Beas-2B cell transformation, and cancer stem-like cells were enriched in nickel-transformed cell (BNiT) population. The BNiT cancer stem-like cells demonstrated enhanced self-renewal and distinctive differentiation properties. In vivo tumorigenesis studies show that BNiT cancer stem-like cells possess a high tumor-initiating capability. It was also demonstrated that superoxide dismutase 1 was involved in the accumulation of cancer stem-like cells; the regulation of superoxide dismutase 1 expression was different in transformed stem-like cells and nontransformed. Overall, the accumulation of stem-like cells and their enhanced stemness functions contribute to nickel-induced tumorigenesis. Our study provides additional insight into the mechanisms by which metals or other chemicals can induce carcinogenesis.
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Affiliation(s)
- Lei Wang
- *Center for Research on Environmental Disease Toxicology and Cancer Biology, and
| | - Jia Fan
- Toxicology and Cancer Biology, and
| | | | - Young-Ok Son
- *Center for Research on Environmental Disease Toxicology and Cancer Biology, and
| | - James T F Wise
- Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Ram Vinod Roy
- *Center for Research on Environmental Disease Toxicology and Cancer Biology, and
| | | | - Jin Dai
- Toxicology and Cancer Biology, and
| | - Poyil Pratheeshkumar
- *Center for Research on Environmental Disease Toxicology and Cancer Biology, and
| | | | - Xianglin Shi
- *Center for Research on Environmental Disease Toxicology and Cancer Biology, and
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11
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Phillips MA, Cánovas A, Wu PW, Islas-Trejo A, Medrano JF, Rice RH. Parallel responses of human epidermal keratinocytes to inorganic SbIII and AsIII. ENVIRONMENTAL CHEMISTRY (COLLINGWOOD, VIC.) 2016; 13:963-970. [PMID: 28713220 PMCID: PMC5507681 DOI: 10.1071/en16019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
SbIII and AsIII are known to exhibit similar chemical properties, but the degree of similarity in their effects on biological systems merits further exploration. Present work compares the responses of human epidermal keratinocytes, a known target cell type for arsenite-induced carcinogenicity, to these metalloids after treatment for a week at environmentally relevant concentrations. Previous work with these cells has shown that arsenite and antimonite have parallel effects in suppressing differentiation, altering levels of several critical enzymes and maintaining colony forming ability. More globally, protein profiling now reveals parallels in SbIII and AsIII effects. The more sensitive technique of transcriptional profiling also shows considerable parallels. Thus, gene expression changes were almost entirely in the same directions for the two treatments, although the degree of change was sometimes significantly different. Inspection of the changes revealed that RYR1 and LRIG1 were among the genes strongly suppressed, consistent with reduced calcium-dependent differentiation and maintenance of EGF-dependent proliferative potential. Moreover, levels of miRNAs in the cells were altered in parallel, with nearly 90% of the 198 most highly expressed ones being suppressed. Among these was miR-203, which is known to decrease proliferative potential. Finally, both SbIII and AsIII were seen to attenuate bone morphogenetic protein 6 induction of dual specificity phosphatases 2 and 14, consistent with maintaining epidermal growth factor receptor signaling. These findings raise the question whether SbIII, like AsIII, could act as a human skin carcinogen.
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Affiliation(s)
- Marjorie A. Phillips
- Department of Environmental Toxicology, University of California, Davis, CA 95616
| | - Angela Cánovas
- Department of Animal Science, University of California, Davis, CA 95616
| | - Pei-Wen Wu
- Department of Environmental Toxicology, University of California, Davis, CA 95616
| | - Alma Islas-Trejo
- Department of Animal Science, University of California, Davis, CA 95616
| | - Juan F. Medrano
- Department of Animal Science, University of California, Davis, CA 95616
| | - Robert H. Rice
- Department of Environmental Toxicology, University of California, Davis, CA 95616
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12
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Ochieng J, Nangami GN, Ogunkua O, Miousse IR, Koturbash I, Odero-Marah V, McCawley LJ, Nangia-Makker P, Ahmed N, Luqmani Y, Chen Z, Papagerakis S, Wolf GT, Dong C, Zhou BP, Brown DG, Colacci AM, Hamid RA, Mondello C, Raju J, Ryan EP, Woodrick J, Scovassi AI, Singh N, Vaccari M, Roy R, Forte S, Memeo L, Salem HK, Amedei A, Al-Temaimi R, Al-Mulla F, Bisson WH, Eltom SE. The impact of low-dose carcinogens and environmental disruptors on tissue invasion and metastasis. Carcinogenesis 2015; 36 Suppl 1:S128-59. [PMID: 26106135 DOI: 10.1093/carcin/bgv034] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The purpose of this review is to stimulate new ideas regarding low-dose environmental mixtures and carcinogens and their potential to promote invasion and metastasis. Whereas a number of chapters in this review are devoted to the role of low-dose environmental mixtures and carcinogens in the promotion of invasion and metastasis in specific tumors such as breast and prostate, the overarching theme is the role of low-dose carcinogens in the progression of cancer stem cells. It is becoming clearer that cancer stem cells in a tumor are the ones that assume invasive properties and colonize distant organs. Therefore, low-dose contaminants that trigger epithelial-mesenchymal transition, for example, in these cells are of particular interest in this review. This we hope will lead to the collaboration between scientists who have dedicated their professional life to the study of carcinogens and those whose interests are exclusively in the arena of tissue invasion and metastasis.
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Affiliation(s)
- Josiah Ochieng
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208, USA, Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA, Department of Biology/Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA 30314, USA, Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA, Department of Pathology, Wayne State University, Detroit, MI 48201, USA, Department of Obstetrics and Gynecology, University of Melbourne, Melbourne, Victoria, Australia, Faculty of Pharmacy, Department of Pathology, Kuwait University, Safat 13110, Kuwait, Department of Otolaryngology, University of Michigan Medical College, Ann Arbor, MI 48109, USA, Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, KY 40506, USA, Department of Environmental and Radiological Health Sciences/Food Science and Human Nutrition, College of Veterinary Medicine and Biomedical Sciences, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA, Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy, Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia, Istituto di Genetica Molecolare, CNR, via Abbiategrasso 207, 27100 Pavia, Italy, Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA, Centre for Advanced Research, King George's Medical University, Chowk, Lucknow, Uttar Pradesh 226003, India, Mediterranean Institute of Oncology, Viagrande 95029, Italy, Urology Department, kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo 12515, Egypt, Department of Experimental and
| | - Gladys N Nangami
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208, USA, Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA, Department of Biology/Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA 30314, USA, Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA, Department of Pathology, Wayne State University, Detroit, MI 48201, USA, Department of Obstetrics and Gynecology, University of Melbourne, Melbourne, Victoria, Australia, Faculty of Pharmacy, Department of Pathology, Kuwait University, Safat 13110, Kuwait, Department of Otolaryngology, University of Michigan Medical College, Ann Arbor, MI 48109, USA, Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, KY 40506, USA, Department of Environmental and Radiological Health Sciences/Food Science and Human Nutrition, College of Veterinary Medicine and Biomedical Sciences, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA, Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy, Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia, Istituto di Genetica Molecolare, CNR, via Abbiategrasso 207, 27100 Pavia, Italy, Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA, Centre for Advanced Research, King George's Medical University, Chowk, Lucknow, Uttar Pradesh 226003, India, Mediterranean Institute of Oncology, Viagrande 95029, Italy, Urology Department, kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo 12515, Egypt, Department of Experimental and
| | - Olugbemiga Ogunkua
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208, USA, Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA, Department of Biology/Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA 30314, USA, Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA, Department of Pathology, Wayne State University, Detroit, MI 48201, USA, Department of Obstetrics and Gynecology, University of Melbourne, Melbourne, Victoria, Australia, Faculty of Pharmacy, Department of Pathology, Kuwait University, Safat 13110, Kuwait, Department of Otolaryngology, University of Michigan Medical College, Ann Arbor, MI 48109, USA, Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, KY 40506, USA, Department of Environmental and Radiological Health Sciences/Food Science and Human Nutrition, College of Veterinary Medicine and Biomedical Sciences, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA, Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy, Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia, Istituto di Genetica Molecolare, CNR, via Abbiategrasso 207, 27100 Pavia, Italy, Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA, Centre for Advanced Research, King George's Medical University, Chowk, Lucknow, Uttar Pradesh 226003, India, Mediterranean Institute of Oncology, Viagrande 95029, Italy, Urology Department, kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo 12515, Egypt, Department of Experimental and
| | - Isabelle R Miousse
- Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Igor Koturbash
- Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Valerie Odero-Marah
- Department of Biology/Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA 30314, USA
| | - Lisa J McCawley
- Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA
| | | | - Nuzhat Ahmed
- Department of Obstetrics and Gynecology, University of Melbourne, Melbourne, Victoria, Australia
| | - Yunus Luqmani
- Faculty of Pharmacy, Department of Pathology, Kuwait University, Safat 13110, Kuwait
| | - Zhenbang Chen
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208, USA, Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA, Department of Biology/Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA 30314, USA, Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA, Department of Pathology, Wayne State University, Detroit, MI 48201, USA, Department of Obstetrics and Gynecology, University of Melbourne, Melbourne, Victoria, Australia, Faculty of Pharmacy, Department of Pathology, Kuwait University, Safat 13110, Kuwait, Department of Otolaryngology, University of Michigan Medical College, Ann Arbor, MI 48109, USA, Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, KY 40506, USA, Department of Environmental and Radiological Health Sciences/Food Science and Human Nutrition, College of Veterinary Medicine and Biomedical Sciences, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA, Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy, Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia, Istituto di Genetica Molecolare, CNR, via Abbiategrasso 207, 27100 Pavia, Italy, Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA, Centre for Advanced Research, King George's Medical University, Chowk, Lucknow, Uttar Pradesh 226003, India, Mediterranean Institute of Oncology, Viagrande 95029, Italy, Urology Department, kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo 12515, Egypt, Department of Experimental and
| | - Silvana Papagerakis
- Department of Otolaryngology, University of Michigan Medical College, Ann Arbor, MI 48109, USA
| | - Gregory T Wolf
- Department of Otolaryngology, University of Michigan Medical College, Ann Arbor, MI 48109, USA
| | - Chenfang Dong
- Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, KY 40506, USA
| | - Binhua P Zhou
- Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, KY 40506, USA
| | - Dustin G Brown
- Department of Environmental and Radiological Health Sciences/Food Science and Human Nutrition, College of Veterinary Medicine and Biomedical Sciences, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Anna Maria Colacci
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy
| | - Roslida A Hamid
- Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia
| | - Chiara Mondello
- Istituto di Genetica Molecolare, CNR, via Abbiategrasso 207, 27100 Pavia, Italy
| | - Jayadev Raju
- Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada
| | - Elizabeth P Ryan
- Department of Environmental and Radiological Health Sciences/Food Science and Human Nutrition, College of Veterinary Medicine and Biomedical Sciences, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA
| | - Jordan Woodrick
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
| | - A Ivana Scovassi
- Istituto di Genetica Molecolare, CNR, via Abbiategrasso 207, 27100 Pavia, Italy
| | - Neetu Singh
- Centre for Advanced Research, King George's Medical University, Chowk, Lucknow, Uttar Pradesh 226003, India
| | - Monica Vaccari
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy
| | - Rabindra Roy
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Stefano Forte
- Mediterranean Institute of Oncology, Viagrande 95029, Italy
| | - Lorenzo Memeo
- Mediterranean Institute of Oncology, Viagrande 95029, Italy
| | - Hosni K Salem
- Urology Department, kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo 12515, Egypt
| | - Amedeo Amedei
- Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy and
| | - Rabeah Al-Temaimi
- Faculty of Pharmacy, Department of Pathology, Kuwait University, Safat 13110, Kuwait
| | - Fahd Al-Mulla
- Faculty of Pharmacy, Department of Pathology, Kuwait University, Safat 13110, Kuwait
| | - William H Bisson
- Environmental and Molecular Toxicology, Environmental Health Sciences Center, Oregon State University, Corvallis, OR 97331, USA
| | - Sakina E Eltom
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN 37208, USA, Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA, Department of Biology/Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA 30314, USA, Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA, Department of Pathology, Wayne State University, Detroit, MI 48201, USA, Department of Obstetrics and Gynecology, University of Melbourne, Melbourne, Victoria, Australia, Faculty of Pharmacy, Department of Pathology, Kuwait University, Safat 13110, Kuwait, Department of Otolaryngology, University of Michigan Medical College, Ann Arbor, MI 48109, USA, Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, KY 40506, USA, Department of Environmental and Radiological Health Sciences/Food Science and Human Nutrition, College of Veterinary Medicine and Biomedical Sciences, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523-1680, USA, Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna 40126, Italy, Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor 43400, Malaysia, Istituto di Genetica Molecolare, CNR, via Abbiategrasso 207, 27100 Pavia, Italy, Toxicology Research Division, Bureau of Chemical Safety Food Directorate, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA, Centre for Advanced Research, King George's Medical University, Chowk, Lucknow, Uttar Pradesh 226003, India, Mediterranean Institute of Oncology, Viagrande 95029, Italy, Urology Department, kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo 12515, Egypt, Department of Experimental and
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13
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Liu ZM, Tseng HY, Cheng YL, Yeh BW, Wu WJ, Huang HS. TG-interacting factor transcriptionally induced by AKT/FOXO3A is a negative regulator that antagonizes arsenic trioxide-induced cancer cell apoptosis. Toxicol Appl Pharmacol 2015; 285:41-50. [PMID: 25791921 DOI: 10.1016/j.taap.2015.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 03/05/2015] [Accepted: 03/06/2015] [Indexed: 12/13/2022]
Abstract
Arsenic trioxide (ATO) is a multi-target drug approved by the Food and Drug Administration as the first-line chemotherapeutic agent for the treatment of acute promyelocytic leukemia. In addition, several clinical trials are being conducted with arsenic-based drugs for the treatment of other hematological malignancies and solid tumors. However, ATO's modest clinical efficacy on some cancers, and potential toxic effects on humans have been reported. Determining how best to reduce these adverse effects while increasing its therapeutic efficacy is obviously a critical issue. Previously, we demonstrated that the JNK-induced complex formation of phosphorylated c-Jun and TG-interacting factor (TGIF) antagonizes ERK-induced cyclin-dependent kinase inhibitor CDKN1A (p21(WAF1/CIP1)) expression and resultant apoptosis in response to ATO in A431 cells. Surprisingly, at low-concentrations (0.1-0.2 μM), ATO increased cellular proliferation, migration and invasion, involving TGIF expression, however, at high-concentrations (5-20 μM), ATO induced cell apoptosis. Using a promoter analysis, TGIF was transcriptionally regulated by ATO at the FOXO3A binding site (-1486 to -1479bp) via the c-Src/EGFR/AKT pathway. Stable overexpression of TGIF promoted advancing the cell cycle into the S phase, and attenuated 20 μM ATO-induced apoptosis. Furthermore, blockage of the AKT pathway enhanced ATO-induced CDKN1A expression and resultant apoptosis in cancer cells, but overexpression of AKT1 inhibited CDKN1A expression. Therefore, we suggest that TGIF is transcriptionally regulated by the c-Src/EGFR/AKT pathway, which plays a role as a negative regulator in antagonizing ATO-induced CDKN1A expression and resultant apoptosis. Suppression of these antagonistic effects might be a promising therapeutic strategy toward improving clinical efficacy of ATO.
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Affiliation(s)
- Zi-Miao Liu
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Hong-Yu Tseng
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Ya-Ling Cheng
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Bi-Wen Yeh
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Urology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wen-Jeng Wu
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Urology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Huei-Sheng Huang
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan.
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14
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Watcharasit P, Suntararuks S, Visitnonthachai D, Thiantanawat A, Satayavivad J. β-catenin involvement in arsenite-induced VEGF expression in neuroblastoma SH-SY5Y cells. ENVIRONMENTAL TOXICOLOGY 2014; 29:672-678. [PMID: 22859221 DOI: 10.1002/tox.21794] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Revised: 06/28/2012] [Accepted: 06/30/2012] [Indexed: 06/01/2023]
Abstract
Arsenic is a widespread contaminant in the environment especially in drinking water. Although it is a known carcinogen in human, the mechanism by which arsenic induces carcinogenesis is not well understood. Among several effects of arsenic, it has been suggested that arsenic-induced vascular endothelial growth factor (VEGF) expression plays a critical role in arsenic carcinogenesis. In the present study, we demonstrated that arsenite induced VEGF expression in neuroblastoma SH-SY5Y cells without induction of HIF-1α, a well-known transcriptional activator for VEGF suggesting that arsenite-induced VEGF expression in SH-SY5Y cells may not require HIF-1α activation. It has been reported that VEGF expression is regulated by multiple transcription factors including β-catenin. We therefore investigated whether β-catenin was involved in arsenite-induced VEGF expression in SH-SY5Y cells. Treatment of arsenite caused β-catenin accumulation in the nucleus. Additionally, arsenite treatment decreased the activity of GSK3, an enzyme that phosphorylates and targets β-catenin for degradation by proteasome, without activation of its upstream kinase, Akt. Inhibition of PI3K/Akt which negatively regulates GSK3 activity by LY294002 resulted in a decrease in arsenite-mediated β-catenin nuclear accumulation, and VEGF expression. These results suggested that β-catenin plays a role in arsenite-induced VEGF in SH-SY5Y cells, and the induction of β-catenin by arsenite is mediated by inhibition of GSK3 without activating its upstream kinase Akt.
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Affiliation(s)
- Piyajit Watcharasit
- Laboratory of Pharmacology, Chulabhorn Research Institute, 54 Kamphaeng Phet 6 Rd, Bangkok 10210, Thailand; Chulabhorn Graduate Institute, 54 Kamphaeng Phet 6 Rd, Bangkok 10210, Thailand; Center of Excellence on Environmental Health and Toxicology (EHT), Office of the Higher Education Commission, Thailand
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15
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Phillips MA, Qin Q, Hu Q, Zhao B, Rice RH. Arsenite suppression of BMP signaling in human keratinocytes. Toxicol Appl Pharmacol 2013; 269:290-6. [PMID: 23566955 DOI: 10.1016/j.taap.2013.02.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 02/25/2013] [Accepted: 02/26/2013] [Indexed: 12/12/2022]
Abstract
Arsenic, a human skin carcinogen, suppresses differentiation of cultured keratinocytes. Exploring the mechanism of this suppression revealed that BMP-6 greatly increased levels of mRNA for keratins 1 and 10, two of the earliest differentiation markers expressed, a process prevented by co-treatment with arsenite. BMP also stimulated, and arsenite suppressed, mRNA for FOXN1, an important transcription factor driving early keratinocyte differentiation. Keratin mRNAs increased slowly after BMP-6 addition, suggesting they are indirect transcriptional targets. Inhibition of Notch1 activation blocked BMP induction of keratins 1 and 10, while FOXN1 induction was largely unaffected. Supporting a requirement for Notch1 signaling in keratin induction, BMP increased levels of activated Notch1, which was blocked by arsenite. BMP also greatly decreased active ERK, while co-treatment with arsenite maintained active ERK. Inhibition of ERK signaling mimicked BMP by inducing keratin and FOXN1 mRNAs and by increasing active Notch1, effects blocked by arsenite. Of 6 dual-specificity phosphatases (DUSPs) targeting ERK, two were induced by BMP unless prevented by simultaneous exposure to arsenite and EGF. Knockdown of DUSP2 or DUSP14 using shRNAs greatly reduced FOXN1 and keratins 1 and 10 mRNA levels and their induction by BMP. Knockdown also decreased activated Notch1, keratin 1 and keratin 10 protein levels, both in the presence and absence of BMP. Thus, one of the earliest effects of BMP is induction of DUSPs, which increases FOXN1 transcription factor and activates Notch1, both required for keratin gene expression. Arsenite prevents this cascade by maintaining ERK signaling, at least in part by suppressing DUSP expression.
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Affiliation(s)
- Marjorie A Phillips
- Department of Environmental Toxicology, University of California, Davis, CA 95616-8588, USA
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16
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Tokar EJ, Person RJ, Sun Y, Perantoni AO, Waalkes MP. Chronic exposure of renal stem cells to inorganic arsenic induces a cancer phenotype. Chem Res Toxicol 2013; 26:96-105. [PMID: 23137061 PMCID: PMC3921970 DOI: 10.1021/tx3004054] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Inorganic arsenic in the drinking water is a multisite human carcinogen that potentially targets the kidney. Recent evidence also indicates that developmental arsenic exposure impacts renal carcinogenesis in humans and mice. Emerging theory indicates that cancer may be a disease of stem cells (SCs) and that there are abundant active SCs during early life. Therefore, we hypothesized that inorganic arsenic targets SCs, or partially differentiated progenitor cells (PCs), for oncogenic transformation. Thus, a rat kidney SC/PC cell line, RIMM-18, was chronically exposed to low-level arsenite (500 nM) for up to 28 weeks. Multiple markers of acquired cancer phenotype were assessed biweekly during arsenic exposure, including secreted matrix metalloproteinase (MMP) activity, proliferation rate, colony formation in soft agar, and cellular invasiveness. Arsenic exposure by 10 weeks and after also induced marked and sustained increases in colony formation, indicative of the loss of contact inhibition, and increased invasiveness, both cancer cell characteristics. Compared to the passage-matched control, chronic arsenic exposure caused exposure-duration dependent increases in secreted MMP-2 and MMP-9 activity, Cox-2 expression, and more rapid proliferation (all >2-fold), characteristics typical of cancer cells. Dysregulation of SC maintenance genes and signaling pathways are common during oncogenesis. During arsenite exposure, expression of several genes associated with normal kidney development and SC regulation and differentiation (i.e., Wt-1, Wnt-4, Bmp-7, etc.) were aberrantly altered. Arsenic-exposed renal SCs produced more nonadherent spheroid bodies that grew much more aggressively in Matrigel, typical of cancer SCs (CSCs). The transformed cells also showed gene overexpression typical of renal SCs/CSCs (CD24, Osr1, Ncam) and arsenic adaptation such as overexpression of Mt-1, Mt2, Sod-1, and Abcc2. These data suggest that inorganic arsenic induced an acquired cancer phenotype in vitro in these rat kidney SCs potentially forming CSCs and, consistent with data in vivo, indicate that these multipotent SCs may be targets of arsenic during renal carcinogenesis.
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Affiliation(s)
- Erik J. Tokar
- National Toxicology Program Laboratory, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, United States
| | - Rachel J. Person
- National Toxicology Program Laboratory, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, United States
| | - Yang Sun
- National Toxicology Program Laboratory, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, United States
| | - Alan O. Perantoni
- Cancer and Developmental Biology Laboratory, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
| | - Michael P. Waalkes
- National Toxicology Program Laboratory, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, United States
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17
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Xu Y, Li Y, Pang Y, Ling M, Shen L, Yang X, Zhang J, Zhou J, Wang X, Liu Q. EMT and stem cell-like properties associated with HIF-2α are involved in arsenite-induced transformation of human bronchial epithelial cells. PLoS One 2012; 7:e37765. [PMID: 22662215 PMCID: PMC3360629 DOI: 10.1371/journal.pone.0037765] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 04/24/2012] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Arsenic is well-established as a human carcinogen, but the molecular mechanisms leading to arsenic-induced carcinogenesis are complex and elusive. It is not been determined if the epithelial-mesenchymal transition (EMT) and stem cell-like properties contribute in causing to carcinogen-induced malignant transformation and subsequent tumor formation. METHODS To investigate the molecular mechanisms underlying EMT and the emergence of cancer stem cell-like properties during neoplastic transformation of human bronchial epithelial (HBE) cells induced by chronic exposure to arsenite. HBE cells were continuously exposed to arsenite. Spheroid formation assays and analyses of side populations (SPs) were performed to confirm that arsenite induces the acquired EMT and cancer stem cell-like phenotype. Treated HBE cells were molecularly characterized by RT-PCR, Western blots, immunofluorescence, Southwestern assays, reporter assays, and chromatin immunoprecipitation. RESULTS With chronic exposure to arsenite, HBE cells undergo an EMT and then acquire a malignant cancer stem cell-like phenotype. Twist1 and Bmi1 are involved in arsenite-induced EMT. The process is directly regulated by HIF-2α. The self-renewal genes, Oct4, Bmi1, and ALDH1, are necessary for arsenite-mediated maintenance of stem cells. CONCLUSIONS EMT, regulated by HIF-2α, and the development of a cancer stem cell-like phenotype are associated with arsenite-induced transformation of HBE cells.
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Affiliation(s)
- Yuan Xu
- Institute of Toxicology, Nanjing Medical University, Nanjing, People's Republic of China
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, People's Republic of China
| | - Yuan Li
- Institute of Toxicology, Nanjing Medical University, Nanjing, People's Republic of China
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, People's Republic of China
| | - Ying Pang
- Institute of Toxicology, Nanjing Medical University, Nanjing, People's Republic of China
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, People's Republic of China
| | - Min Ling
- Institute of Toxicology, Nanjing Medical University, Nanjing, People's Republic of China
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, People's Republic of China
| | - Lu Shen
- Institute of Toxicology, Nanjing Medical University, Nanjing, People's Republic of China
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, People's Republic of China
| | - Xiaojun Yang
- Department of General Surgery, The Second Affiliated Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Jianping Zhang
- Department of General Surgery, The Second Affiliated Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Jianwei Zhou
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, People's Republic of China
| | - Xinru Wang
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qizhan Liu
- Institute of Toxicology, Nanjing Medical University, Nanjing, People's Republic of China
- The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, People's Republic of China
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18
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Martinez VD, Becker-Santos DD, Vucic EA, Lam S, Lam WL. Induction of human squamous cell-type carcinomas by arsenic. J Skin Cancer 2011; 2011:454157. [PMID: 22175027 PMCID: PMC3235812 DOI: 10.1155/2011/454157] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 10/07/2011] [Indexed: 01/14/2023] Open
Abstract
Arsenic is a potent human carcinogen. Around one hundred million people worldwide have potentially been exposed to this metalloid at concentrations considered unsafe. Exposure occurs generally through drinking water from natural geological sources, making it difficult to control this contamination. Arsenic biotransformation is suspected to have a role in arsenic-related health effects ranging from acute toxicities to development of malignancies associated with chronic exposure. It has been demonstrated that arsenic exhibits preference for induction of squamous cell carcinomas in the human, especially skin and lung cancer. Interestingly, keratins emerge as a relevant factor in this arsenic-related squamous cell-type preference. Additionally, both genomic and epigenomic alterations have been associated with arsenic-driven neoplastic process. Some of these aberrations, as well as changes in other factors such as keratins, could explain the association between arsenic and squamous cell carcinomas in humans.
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Affiliation(s)
- Victor D. Martinez
- Department of Integrative Oncology, BC Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada V5Z 1L3
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19
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Sun Y, Tokar EJ, Waalkes MP. Overabundance of putative cancer stem cells in human skin keratinocyte cells malignantly transformed by arsenic. Toxicol Sci 2011; 125:20-9. [PMID: 22011395 DOI: 10.1093/toxsci/kfr282] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Arsenic is a human skin carcinogen. Cancer is probably a disease driven by stem cells (SCs), and SCs are likely a key target during arsenic oncogenesis. In utero arsenic exposure predisposes mice to skin cancers that overproduce cancer SCs (CSCs) and have distorted CSC signaling and population dynamics. Therefore, we hypothesized CSC accumulation may occur during arsenic-induced malignant transformation in vitro of human skin keratinocytes. Thus, the HaCaT cell line, malignantly transformed by arsenite (100 nM, 30 weeks; termed As-TM cells) in prior work, was further studied for the quantity and nature of SCs after this transformation. SCs were isolated from passage-matched control and As-TM cells by a magnetic bead system that enriches for CD34-positive cells. There were 2.5 times more SCs isolated from As-TM cells than control. Holoclone production from As-TM putative CSCs was 2.5-fold higher by 1 week and 3.5-fold higher by 2 weeks than control SCs. Potential malignant phenotype was assessed in isolated SC/CSCs. Transcript level of SC/CSC markers were elevated in both isolated As-TM CSCs and control SCs compared with parental cells, but compared with control SCs, As-TM putative CSCs had elevated CD34, K5, K14, K15, and K19 transcripts and dramatically stronger staining for p63, Rac1, K5, Notch1, and K19. As-TM putative CSCs also showed markedly elevated MMP-9 secretion and colony formation, indicators of cancer phenotype, even compared with total population of As-TM cells. Thus, malignant phenotype is particularly pronounced in CSCs after arsenic-induced transformation of human skin cells and occurs concurrently with a potential overproduction of these cells.
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Affiliation(s)
- Yang Sun
- National Toxicology Program Laboratory, Inorganic Toxicology Group, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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Tokar EJ, Qu W, Waalkes MP. Arsenic, stem cells, and the developmental basis of adult cancer. Toxicol Sci 2011; 120 Suppl 1:S192-203. [PMID: 21071725 PMCID: PMC3043086 DOI: 10.1093/toxsci/kfq342] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 11/08/2010] [Indexed: 12/18/2022] Open
Abstract
That chemical insults or nutritive changes during in utero and/or postnatal life can emerge as diseases much later in life are now being accepted as a recurring phenomenon. In this regard, inorganic arsenic is a multisite human carcinogen found at high levels in the drinking water of millions of people, although it has been difficult until recently to produce tumors in rodents with this metalloid. A mouse transplacental model has been developed where maternal exposure to inorganic arsenic either acts as a complete carcinogen or enhances carcinogenic response to other agents given subsequently in the offspring, producing tumors during adulthood. Similarly, human data now have emerged showing that arsenic exposure during the in utero period and/or in early life is associated with cancer in adulthood. The mouse arsenic transplacental model produces tumors or enhances response to other agents in multiple strains and tissues, including sites concordant with human targets of arsenic carcinogenesis. It is now believed that cancer often is a stem cell (SC)-based disease, and there is no reason to think cancer induced by developmental chemical exposure is any different. Indeed, arsenic impacts human SC population dynamics in vitro by blocking exit into differentiation pathways and whereby creating more key targets for transformation. In fact, during in vitro malignant transformation, arsenic causes a remarkable survival selection of SCs, creating a marked overabundance of cancer SCs (CSCs) compared with other carcinogens once a cancer phenotype is obtained. In addition, skin cancers produced following in utero arsenic exposure in mice are highly enriched in CSCs. Thus, arsenic impacts key, long-lived SC populations as critical targets to cause or facilitate later oncogenic events in adulthood as a possible mechanism of developmental basis of adult disease.
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Affiliation(s)
| | | | - Michael P. Waalkes
- National Toxicology Program Laboratories, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
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Tokar EJ, Diwan BA, Ward JM, Delker DA, Waalkes MP. Carcinogenic effects of "whole-life" exposure to inorganic arsenic in CD1 mice. Toxicol Sci 2011; 119:73-83. [PMID: 20937726 PMCID: PMC3003832 DOI: 10.1093/toxsci/kfq315] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 10/06/2010] [Indexed: 01/21/2023] Open
Abstract
In a previously developed mouse model, arsenic exposure in utero induces tumors at multiple sites in the offspring as adults, often duplicating human targets. However, human environmental inorganic arsenic exposure occurs during the entire life span, not just part of gestation. Thus, "whole-life" inorganic arsenic carcinogenesis in mice was studied. CD1 mice were exposed to 0, 6, 12, or 24 ppm arsenic in the drinking water 2 weeks prior to breeding, during pregnancy, lactation, and after weaning through adulthood. Tumors were assessed in offspring until 2 years of age. Arsenic induced dose-related increases in lung adenocarcinoma (both sexes), hepatocellular carcinoma (both sexes), gallbladder tumors (males), and uterine carcinomas. Arsenic induced dose-related increases in ovarian tumors (including carcinomas) starting with the lowest dose. Adrenal tumors increased at all doses (both sexes). Arsenic-induced lung and liver cancers were highly enriched for cancer stem cells, consistent with prior work with skin cancers stimulated by prenatal arsenic. Reproductive tract tumors overexpressed cyclooxygenase-2 and estrogen receptor-α. Arsenic target sites were remarkably similar to prior transplacental studies, although tumors from whole-life exposure were generally more aggressive and frequent. This may indicate that arsenic-induced events in utero dictate target site in some tissues, whereas other exposure periods of arsenic enhance incidence or progression, though other factors could be at play, like cumulative dose. Whole-life arsenic exposure induced tumors at dramatically lower external doses than in utero arsenic only while more realistically duplicating human exposure.
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Affiliation(s)
- Erik J. Tokar
- Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, and National Toxicology Program, The National Institute of Environmental Health Sciences, Research Triangle Park, Raleigh, North Carolina 27709
| | - Bhalchandra A. Diwan
- Basic Research Program, SAIC-Frederick, National Cancer Institute at Frederick, Frederick, Maryland 21773
| | | | - Don A. Delker
- University of Utah, School of Medicine, 30 North 1900 East, Salt Lake City, Utah 84132
| | - Michael P. Waalkes
- Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, and National Toxicology Program, The National Institute of Environmental Health Sciences, Research Triangle Park, Raleigh, North Carolina 27709
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Tokar EJ, Benbrahim-Tallaa L, Ward JM, Lunn R, Sams RL, Waalkes MP. Cancer in experimental animals exposed to arsenic and arsenic compounds. Crit Rev Toxicol 2010; 40:912-27. [PMID: 20812815 PMCID: PMC3076186 DOI: 10.3109/10408444.2010.506641] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Inorganic arsenic is a ubiquitous environmental contaminant that has long been considered a human carcinogen. Recent studies raise further concern about the metalloid as a major, naturally occurring carcinogen in the environment. However, during this same period it has proven difficult to provide experimental evidence of the carcinogenicity of inorganic arsenic in laboratory animals and, until recently, there was considered to be a lack of clear evidence for carcinogenicity of any arsenical in animals. More recent work with arsenical methylation metabolites and early life exposures to inorganic arsenic has now provided evidence of carcinogenicity in rodents. Given that tens of millions of people worldwide are exposed to potentially unhealthy levels of environmental arsenic, in vivo rodent models of arsenic carcinogenesis are a clear necessity for resolving critical issues, such as mechanisms of action, target tissue specificity, and sensitive subpopulations, and in developing strategies to reduce cancers in exposed human populations. This work reviews the available rodent studies considered relevant to carcinogenic assessment of arsenicals, taking advantage of the most recent review by the International Agency for Research on Cancer (IARC) that has not yet appeared as a full monograph but has been summarized (IARC, 2009 , IARC Special Report: Policy, Vol. 10. Lyon: IARC Press, 453–454). Many valid studies show that arsenic can interact with other carcinogens/agents to enhance oncogenesis, and help elucidate mechanisms, and these too are summarized in this review. Finally, this body of rodent work is discussed in light of its impact on mechanisms and in the context of the persistent argument that arsenic is not carcinogenic in animals.
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Affiliation(s)
- Erik J. Tokar
- National Toxicology Program, National Institute of Environmental Health Sciences and Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, Research Triangle Park, NC
| | | | - Jerold M. Ward
- Global VetPathology, 10513 Wayridge Drive, Montgomery Village, MD
| | - Ruth Lunn
- Report on Carcinogens Office, National Toxicology Program, National Institute of Environmental Health Science, Research Triangle Park, NC
| | - Reeder L. Sams
- National Center for Environmental Assessment, Office of Research and Development, US EPA, Research Triangle Park, NC
| | - Michael P. Waalkes
- National Toxicology Program, National Institute of Environmental Health Sciences and Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, Research Triangle Park, NC
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Reznikova TV, Phillips MA, Patterson TJ, Rice RH. Opposing actions of insulin and arsenite converge on PKCdelta to alter keratinocyte proliferative potential and differentiation. Mol Carcinog 2010; 49:398-409. [PMID: 20082316 DOI: 10.1002/mc.20612] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
When cultured human keratinocytes reach confluence, they undergo a program of changes replicating features of differentiation in vivo, including exit from the proliferative pool, increased cell size, and expression of specialized differentiation marker proteins. Previously, we showed that insulin is required for some of these steps and that arsenite, a human carcinogen in skin and other epithelia, opposes the differentiation process. In present work, we show that insulin signaling, probably through the IGF-I receptor, is required for the increase in cell size accompanying differentiation and that this is opposed by arsenite. We further examine the impact of insulin and arsenite on PKCdelta, a known key regulator of keratinocyte differentiation, and show that insulin increases the amount, tyrosine phosphorylation, and membrane localization of PKCdelta. All these effects are prevented by exposure of cells to arsenite or to inhibitors of downstream effectors of insulin (phosphotidylinositol 3-kinase and mammalian target of rapamycin). Retrovirally mediated expression of activated PKCdelta resulted in increased loss of proliferative potential after confluence and greatly increased formation of cross-linked envelopes, a marker of keratinocyte terminal differentiation. These effects were prevented by removal of insulin, but not by arsenite addition. We further demonstrate a role for src family kinases in regulation of PKCdelta. Finally, inhibiting epidermal growth factor receptor kinase activity diminished the ability of arsenite to prevent cell enlargement and to suppress insulin-dependent PKCdelta amount and tyrosine 311 phosphorylation. Thus suppression of PKCdelta signaling is a critical feature of arsenite action in preventing keratinocyte differentiation and maintaining proliferative capability.
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Affiliation(s)
- Tatiana V Reznikova
- Department of Environmental Toxicology, University of California, Davis, California 95616-8588, USA
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Tokar EJ, Qu W, Liu J, Liu W, Webber MM, Phang JM, Waalkes MP. Arsenic-specific stem cell selection during malignant transformation. J Natl Cancer Inst 2010; 102:638-49. [PMID: 20339138 PMCID: PMC2864291 DOI: 10.1093/jnci/djq093] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 02/02/2010] [Accepted: 02/26/2010] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Arsenic is a carcinogen that targets the urogenital system, including the prostate. Although the mechanisms for arsenic-induced carcinogenesis are undefined, arsenic drives overaccumulation of stem cells and cancer stem cells (CSCs) in vivo and in vitro, indicating that these cells are a key target population. Disruption of stem cell population dynamics may be critical to acquisition of cancer phenotype. We tested the hypothesis that prostate stem cells have a survival selection advantage during arsenic exposure that favors their accumulation and facilitates their malignant transformation. METHODS Innate and acquired resistance to acute (24-72 hours of exposure) and chronic (6 weeks of exposure) arsenite-induced cytolethality and apoptosis were assessed in a human prostate stem cell line (WPE-stem) and the mature parental cell line (RWPE-1). Real-time reverse transcription-polymerase chain reaction and/or Western blot analysis was used to measure the expression of apoptosis-, stress-, and arsenic-related genes. Arsenic-, cadmium-, and N-methyl-N-nitrosourea-induced isogenic malignant transformants of RWPE-1 cells were compared for acquisition of CSC-like qualities by holoclone and sphere formation assays, growth in soft agar, and expression of CSC biomarkers. All statistical tests were two-sided. RESULTS WPE-stem cells showed innate resistance to arsenic-induced cytolethality (arsenite concentration lethal to 50% of the cells [LC(50)] = 32.4 microM, 95% confidence interval [CI] = 31.5 to 33.3 muM) and apoptosis compared with parental RWPE-1 cells (LC(50) = 10.4 muM, 95% CI = 7.4 to 13.4 microM). Compared with RWPE-1 cells, WPE-stem cells showed noticeably higher expression of antiapoptotic (ie, BCL2, MT), stress-related (ie, NFE2L2, SOD1, PRODH), and arsenic adaptation (ie, ABCC1, GSTP1) factors and noticeably lower expression of proapoptotic factors (ie, BAX, caspases 3, 7, 8, and 9). WPE-stem cells also showed hyper-adaptability to chronic arsenite exposure (5 microM, 6 weeks) compared with RWPE-1 cells (LC(50) = 94.7 vs 32.1 microM, difference = 62.6 muM, 95% CI = 53.3 to 71.9 muM) at levels that in previous work induced a malignant phenotype in RWPE-1 after 30 weeks of exposure. Quantification of CSC-like cells in isogenic RWPE-1 transformants showed that marked overproduction was unique to a malignant phenotype acquired in response to arsenic exposure but not in response to cadmium or N-methyl-N-nitrosourea exposure. CONCLUSIONS An apparent stem cell survival advantage with regard to arsenic causes selection during malignant transformation that manifests itself as an overabundance of CSC-like cells specifically after arsenic-driven acquisition of malignant phenotype. The increased resistance to apoptosis and arsenite hyper-adaptability of WPE-stem cells suggests that arsenite transformation of RWPE-1 cells involves an increase in the number of CSC-like cells.
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Tokar EJ, Diwan BA, Waalkes MP. Arsenic exposure transforms human epithelial stem/progenitor cells into a cancer stem-like phenotype. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:108-15. [PMID: 20056578 PMCID: PMC2831952 DOI: 10.1289/ehp.0901059] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Accepted: 09/10/2009] [Indexed: 05/19/2023]
Abstract
BACKGROUND Inorganic arsenic is a ubiquitous environmental carcinogen affecting millions of people worldwide. Evolving theory predicts that normal stem cells (NSCs) are transformed into cancer stem cells (CSCs) that then drive oncogenesis. In humans, arsenic is carcinogenic in the urogenital system (UGS), including the bladder and potentially the prostate, whereas in mice arsenic induces multi-organ UGS cancers, indicating that UGS NSCs may represent targets for carcino-genic initiation. However, proof of emergence of CSCs induced by arsenic in a stem cell population is not available. METHODS We continuously exposed the human prostate epithelial stem/progenitor cell line WPE-stem to an environmentally relevant level of arsenic (5 microM) in vitro and determined the acquired cancer phenotype. RESULTS WPE-stem cells rapidly acquired a malignant CSC-like phenotype by 18 weeks of exposure, becoming highly invasive, losing contact inhibition, and hyper-secreting matrix metalloproteinase-9. When hetero-transplanted, these cells (designated As-CSC) formed highly pleomorphic, aggressive tumors with immature epithelial- and mesenchymal-like cells, suggesting a highly pluripotent cell of origin. Consistent with tumor-derived CSCs, As-CSCs formed abundant free-floating spheres enriched in CSC-like cells, as confirmed by molecular analysis and the fact that only these floating cells formed xeno-graft tumors. An early loss of NSC self-renewal gene expression (p63, ABCG2, BMI-1, SHH, OCT-4, NOTCH-1) during arsenite exposure was sub-sequently reversed as the tumor suppressor gene PTEN was progressively suppressed and the CSC-like phenotype acquired. CONCLUSIONS Arsenite transforms prostate epithelial stem/progenitor cells into CSC-like cells, indicating that it can produce CSCs from a model NSC population.
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MESH Headings
- Adult Stem Cells/drug effects
- Adult Stem Cells/metabolism
- Adult Stem Cells/pathology
- Animals
- Arsenic/toxicity
- Arsenites/toxicity
- Carcinogens, Environmental/toxicity
- Cell Line
- Cell Transformation, Neoplastic/drug effects
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/pathology
- Gene Expression/drug effects
- Humans
- Male
- Matrix Metalloproteinase 9/metabolism
- Membrane Proteins/genetics
- Mice
- Mice, Nude
- Neoplasms, Experimental/etiology
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/pathology
- Neoplastic Stem Cells/drug effects
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Neoplastic Stem Cells/transplantation
- PTEN Phosphohydrolase/genetics
- Phenotype
- Prostate/cytology
- Prostate/metabolism
- Spheroids, Cellular/pathology
- Transplantation, Heterologous
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Affiliation(s)
- Erik J. Tokar
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Bhalchandra A. Diwan
- Basic Research Program, SAIC-Frederick, Inc., National Cancer Institute-Frederick, Frederick, Maryland, USA
| | - Michael P. Waalkes
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
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Sinitsyna NN, Reznikova TV, Qin Q, Song H, Phillips MA, Rice RH. Arsenite suppression of involucrin transcription through AP1 promoter sites in cultured human keratinocytes. Toxicol Appl Pharmacol 2009; 243:275-82. [PMID: 20006635 DOI: 10.1016/j.taap.2009.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 11/07/2009] [Accepted: 12/05/2009] [Indexed: 02/08/2023]
Abstract
While preserving keratinocyte proliferative ability, arsenite suppresses cellular differentiation markers by preventing utilization of AP1 transcriptional response elements. In present experiments, arsenite had a dramatic effect in electrophoretic mobility supershift analysis of proteins binding to an involucrin promoter AP1 response element. Without arsenite treatment, binding of JunB and Fra1 was readily detected in nuclear extracts from preconfluent cultures and was not detected a week after confluence, while c-Fos was detected only after confluence. By contrast, band shift of nuclear extracts from arsenite treated cultures showed only JunB and Fra1 binding in postconfluent as well as preconfluent cultures. Immunoblotting of cell extracts showed that arsenite treatment prevented the loss of Fra1 and the increase in c-Fos proteins that occurred after confluence in untreated cultures. Chromatin immunoprecipitation assays demonstrated substantial reduction of c-Fos and acetylated histone H3 at the proximal and distal AP1 response elements in the involucrin promoter and of coactivator p300 at the proximal element. Alteration of AP1 transcription factors was also examined in response to treatment with four metal containing compounds (chromate, vanadate, hemin, divalent cadmium) that also suppress involucrin transcription. These agents all influenced transcription at AP1 elements in a transcriptional reporter assay, but exhibited less effect than arsenite on binding activity assessed by mobility shift and chromatin immunoprecipitation and displayed variable effects on AP1 protein levels. These findings help trace a mechanism by which transcriptional effects of arsenite become manifest and help rationalize the unique action of arsenite, compared to the other agents, to preserve proliferative ability.
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Affiliation(s)
- Nadezda N Sinitsyna
- Department of Environmental Toxicology, University of California, Davis, CA 95616-8588, USA
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Sun Y, Pi J, Wang X, Tokar EJ, Liu J, Waalkes MP. Aberrant cytokeratin expression during arsenic-induced acquired malignant phenotype in human HaCaT keratinocytes consistent with epidermal carcinogenesis. Toxicology 2009; 262:162-70. [PMID: 19524636 PMCID: PMC2747077 DOI: 10.1016/j.tox.2009.06.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 05/26/2009] [Accepted: 06/02/2009] [Indexed: 01/05/2023]
Abstract
Inorganic arsenic is a known human skin carcinogen. Chronic arsenic exposure results in various human skin lesions, including hyperkeratosis and squamous cell carcinoma (SCC), both characterized by distorted cytokeratin (CK) production. Prior work shows the human skin keratinocyte HaCaT cell line, when exposed chronically for >25 weeks to a low level of inorganic arsenite (100nM) results in cells able to produce aggressive SCC upon inoculation into nude mice. In the present study, CK expression analysis was performed in arsenic-exposed HaCaT cells during the progressive acquisition of this malignant phenotype (0-20 weeks) to further validate this model as relevant to epidermal carcinogenesis induced by arsenic in humans. Indeed, we observed clear evidence of acquired cancer phenotype by 20 weeks of arsenite exposure including the formation of giant cells, a >4-fold increase in colony formation in soft agar and a approximately 2.5-fold increase in matrix metalloproteinase-9 secretion, an enzyme often secreted by cancer cells to help invade through the local extra-cellular matrix. During this acquired malignant phenotype, various CK genes showed markedly altered expression at the transcript and protein levels in a time-dependent manner. For example, CK1, a marker of hyperkeratosis, increased up to 34-fold during arsenic-induced transformation, while CK13, a marker for dermal cancer progression, increased up to 45-fold. The stem cell marker, CK15, increased up to 7-fold, particularly during the later stages of arsenic exposure, indicating a potential emergence of cancer stem-like cells with arsenic-induced acquired malignant phenotype. The expression of involucrin and loricrin, markers for keratinocyte differentiation, increased up to 9-fold. Thus, during arsenic-induced acquired cancer phenotype in human keratinocytes, dramatic and dynamic alterations in CK expression occur which are consistent with the process of epidermal carcinogenesis helping validate this as an appropriate model for the study of arsenic-induced skin cancer.
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Affiliation(s)
- Yang Sun
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at National Institute of Environmental Health Sciences, National Institutes of Health, Reasearch Triangle Park, North Carolina 27709, USA
| | - Jingbo Pi
- Division of Translational Biology, The Hamner Institutes for Health Sciences, 6 Davis Dr., Research Triangle Park, NC 27709, USA
| | - Xueqian Wang
- Laboratory of Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
| | - Erik J. Tokar
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at National Institute of Environmental Health Sciences, National Institutes of Health, Reasearch Triangle Park, North Carolina 27709, USA
| | - Jie Liu
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at National Institute of Environmental Health Sciences, National Institutes of Health, Reasearch Triangle Park, North Carolina 27709, USA
| | - Michael P. Waalkes
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at National Institute of Environmental Health Sciences, National Institutes of Health, Reasearch Triangle Park, North Carolina 27709, USA
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Waalkes MP, Liu J, Germolec DR, Trempus CS, Cannon RE, Tokar EJ, Tennant RW, Ward JM, Diwan BA. Arsenic exposure in utero exacerbates skin cancer response in adulthood with contemporaneous distortion of tumor stem cell dynamics. Cancer Res 2008; 68:8278-85. [PMID: 18922899 PMCID: PMC2652700 DOI: 10.1158/0008-5472.can-08-2099] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Arsenic is a carcinogen with transplacental activity that can affect human skin stem cell population dynamics in vitro by blocking exit into differentiation pathways. Keratinocyte stem cells (KSC) are probably a key target in skin carcinogenesis. Thus, we tested the effects of fetal arsenic exposure in Tg.AC mice, a strain sensitive to skin carcinogenesis via activation of the v-Ha-ras transgene likely in KSCs. After fetal arsenic treatment, offspring received topical 12-O-tetradecanoyl phorbol-13-acetate (TPA) through adulthood. Arsenic alone had no effect, whereas TPA alone induced papillomas and squamous cell carcinomas (SCC). However, fetal arsenic treatment before TPA increased SCC multiplicity 3-fold more than TPA alone, and these SCCs were much more aggressive (invasive, etc.). Tumor v-Ha-ras levels were 3-fold higher with arsenic plus TPA than TPA alone, and v-Ha-ras was overexpressed early on in arsenic-treated fetal skin. CD34, considered a marker for both KSCs and skin cancer stem cells, and Rac1, a key gene stimulating KSC self-renewal, were greatly increased in tumors produced by arsenic plus TPA exposure versus TPA alone, and both were elevated in arsenic-treated fetal skin. Greatly increased numbers of CD34-positive probable cancer stem cells and marked overexpression of RAC1 protein occurred in tumors induced by arsenic plus TPA compared with TPA alone. Thus, fetal arsenic exposure, although by itself oncogenically inactive in skin, facilitated cancer response in association with distorted skin tumor stem cell signaling and population dynamics, implicating stem cells as a target of arsenic in the fetal basis of skin cancer in adulthood.
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Affiliation(s)
- Michael P Waalkes
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at NIEHS, North Carolina27709, USA.
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Abstract
Arsenic is a well-known human skin carcinogen whose mechanism of action remains to be elucidated. In this work using cultured human epidermal cells, arsenite suppressed accumulation of the transcriptionally active intracellular domain of Notch1. The cells responded to an active peptide from the Notch1 ligand, Jagged1, with increased levels of differentiation marker mRNAs and decreased colony-forming ability. Arsenite suppressed Jagged1 effects and expression of Jagged1 mRNA as well. Moreover, exposure of the cells to a gamma-secretase inhibitor prevented Notch1 processing, decreased cell size and differentiation marker expression, and increased proliferative potential, all effects that occur with arsenite treatment. Thus, arsenite action in suppressing keratinocyte differentiation while maintaining germinative capability could be due to inhibition of Notch1 signaling subsequent to ligand binding. This work also revealed that such arsenite action depends upon epidermal growth factor receptor kinase activity. These findings may help to explain how arsenite, by decreasing generation of the tumor suppressor Notch1, contributes to skin carcinogenesis.
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