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Lou Q, Chen F, Li B, Zhang M, Yin F, Liu X, Zhang Z, Zhang X, Fan C, Gao Y, Yang Y. Malignant growth of arsenic-transformed cells depends on activated Akt induced by reactive oxygen species. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2023; 33:284-298. [PMID: 34974760 DOI: 10.1080/09603123.2021.2023113] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Arsenic is an identified carcinogen for humans.In this study, chronic exposure of human hepatocyte L-02 to low-doses of inorganic arsenic caused cell malignant proliferation. Meanwhile, compared with normal L-02 cells, arsenic-transformed malignant cells, L-02-As displayed more ROS and significantly higher Cyclin D1 expression as well as aerobic glycolysis. Moreover, Akt activation is followed by the upregulation of Cyclin D1 and HK2 expression in L-02-As cells, since inhibition of Akt activity by Ly294002 attenuated the colony formation in soft agar and decreased the levels of Cyclin D1 and HK2. In addition, scavenging of ROS by NAC resulted in a decreased expression of phospho-Akt, HK2 and Cyclin D1, and attenuates the ability of anchorage-independent growth ofL-02-As cells, suggested that ROS mediated the Akt activation in L-02-As cells. In summary, our results demonstrated that ROS contributes to the malignant phenotype of arsenic-transformed human hepatocyte L-02-As via the activation of Akt pathway.
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Affiliation(s)
- Qun Lou
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Fuxun Chen
- Yantai Center for Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Yantai, Shandong, China
| | - Bingyang Li
- Yantai Center for Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Yantai, Shandong, China
| | - Meichen Zhang
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Fanshuo Yin
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Xiaona Liu
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Zaihong Zhang
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Xin Zhang
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Chenlu Fan
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Yanhui Gao
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Yanmei Yang
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province, China
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2
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Martinez VD, Lam WL. Health Effects Associated With Pre- and Perinatal Exposure to Arsenic. Front Genet 2021; 12:664717. [PMID: 34659330 PMCID: PMC8511415 DOI: 10.3389/fgene.2021.664717] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 07/26/2021] [Indexed: 12/11/2022] Open
Abstract
Inorganic arsenic is a well-established human carcinogen, able to induce genetic and epigenetic alterations. More than 200 million people worldwide are exposed to arsenic concentrations in drinking water exceeding the recommended WHO threshold (10μg/l). Additionally, chronic exposure to levels below this threshold is known to result in long-term health effects in humans. The arsenic-related health effects in humans are associated with its biotransformation process, whereby the resulting metabolites can induce molecular damage that accumulates over time. The effects derived from these alterations include genomic instability associated with oxidative damage, alteration of gene expression (including coding and non-coding RNAs), global and localized epigenetic reprogramming, and histone posttranslational modifications. These alterations directly affect molecular pathways involved in the onset and progression of many conditions that can arise even decades after the exposure occurs. Importantly, arsenic metabolites generated during its biotransformation can also pass through the placental barrier, resulting in fetal exposure to this carcinogen at similar levels to those of the mother. As such, more immediate effects of the arsenic-induced molecular damage can be observed as detrimental effects on fetal development, pregnancy, and birth outcomes. In this review, we focus on the genetic and epigenetic damage associated with exposure to low levels of arsenic, particularly those affecting early developmental stages. We also present how these alterations occurring during early life can impact the development of certain diseases in adult life.
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Affiliation(s)
- Victor D. Martinez
- Department of Pathology, Dalhousie University, Halifax, NS, Canada
- Department of Pathology and Laboratory Medicine, IWK Health Centre, Halifax, NS, Canada
- Beatrice Hunter Cancer Research Institute, Halifax, NS, Canada
- The Canadian Environmental Exposures in Cancer (CE2C) Network, Halifax, NS, Canada
| | - Wan L. Lam
- The Canadian Environmental Exposures in Cancer (CE2C) Network, Halifax, NS, Canada
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
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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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Cooperation between NRF2-mediated transcription and MDIG-dependent epigenetic modifications in arsenic-induced carcinogenesis and cancer stem cells. Semin Cancer Biol 2021; 76:310-318. [PMID: 33823236 DOI: 10.1016/j.semcancer.2021.03.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/27/2021] [Accepted: 03/28/2021] [Indexed: 02/07/2023]
Abstract
Environmental exposure to arsenic, a well-established carcinogen linked to a number of human cancers, is a public health concern in many areas of the world. Despite extensive studies on the molecular mechanisms of arsenic-induced carcinogenesis, how initial cellular responses, such as activation of stress kinases and the generation of reactive oxygen species, converge to affect the transcriptional and/or epigenetic reprogramming required for the malignant transformation of normal cells or normal stem cells remains to be elucidated. In this review, we discuss some recent discoveries showing how the transcription factor NRF2 and an epigenetic regulator, MDIG, contribute to the arsenic-induced generation of cancer stem-like cells (CSCs) as determined by applying CRISPR-Cas9 gene editing and chromosome immunoprecipitation followed by DNA sequencing (ChIP-seq).
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Koual M, Tomkiewicz C, Cano-Sancho G, Antignac JP, Bats AS, Coumoul X. Environmental chemicals, breast cancer progression and drug resistance. Environ Health 2020; 19:117. [PMID: 33203443 PMCID: PMC7672852 DOI: 10.1186/s12940-020-00670-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 10/21/2020] [Indexed: 05/04/2023]
Abstract
Breast cancer (BC) is one of the most common causes of cancer in the world and the second leading cause of cancer deaths among women. Mortality is associated mainly with the development of metastases. Identification of the mechanisms involved in metastasis formation is, therefore, a major public health issue. Among the proposed risk factors, chemical environment and pollution are increasingly suggested to have an effect on the signaling pathways involved in metastatic tumor cells emergence and progression. The purpose of this article is to summarize current knowledge about the role of environmental chemicals in breast cancer progression, metastasis formation and resistance to chemotherapy. Through a scoping review, we highlight the effects of a wide variety of environmental toxicants, including persistent organic pollutants and endocrine disruptors, on invasion mechanisms and metastatic processes in BC. We identified the epithelial-to-mesenchymal transition and cancer-stemness (the stem cell-like phenotype in tumors), two mechanisms suspected of playing key roles in the development of metastases and linked to chemoresistance, as potential targets of contaminants. We discuss then the recently described pro-migratory and pro-invasive Ah receptor signaling pathway and conclude that his role in BC progression is still controversial. In conclusion, although several pertinent pathways for the effects of xenobiotics have been identified, the mechanisms of actions for multiple other molecules remain to be established. The integral role of xenobiotics in the exposome in BC needs to be further explored through additional relevant epidemiological studies that can be extended to molecular mechanisms.
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Affiliation(s)
- Meriem Koual
- INSERM UMR-S1124, 3TS, Toxicologie Pharmacologie et Signalisation Cellulaire, Université de Paris, Paris, France.
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Service de Chirurgie Cancérologique Gynécologique et du Sein, Paris, France.
- Faculté de Médecine, Université de Paris, Paris, France.
| | - Céline Tomkiewicz
- INSERM UMR-S1124, 3TS, Toxicologie Pharmacologie et Signalisation Cellulaire, Université de Paris, Paris, France
- Faculté de Médecine, Université de Paris, Paris, France
| | | | | | - Anne-Sophie Bats
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Service de Chirurgie Cancérologique Gynécologique et du Sein, Paris, France
- Faculté de Médecine, Université de Paris, Paris, France
- INSERM UMR-S1147, Equipe labellisée Ligue Nationale Contre le Cancer, Université de Paris, Paris, France
| | - Xavier Coumoul
- INSERM UMR-S1124, 3TS, Toxicologie Pharmacologie et Signalisation Cellulaire, Université de Paris, Paris, France.
- Faculté de Médecine, Université de Paris, Paris, France.
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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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7
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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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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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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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Wu X, Yang B, Hu Y, Sun R, Wang H, Fu J, Hou Y, Pi J, Xu Y. NRF2 Is a Potential Modulator of Hyperresistance to Arsenic Toxicity in Stem-Like Keratinocytes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:7417694. [PMID: 29081891 PMCID: PMC5610874 DOI: 10.1155/2017/7417694] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 07/07/2017] [Accepted: 08/01/2017] [Indexed: 12/26/2022]
Abstract
Arsenic is a well-known human carcinogen. Stem cells are indicated to be involved in arsenic carcinogenesis and have a survival selection advantage during arsenic exposure with underlying mechanisms undefined. In the present study, we demonstrated that CD34high-enriched cells derived from HaCaT human keratinocytes showed stem-like phenotypes. These cells were more resistant to arsenic toxicity and had higher arsenic efflux ability than their mature compartments. The master transcription factor in antioxidant defense, nuclear factor erythroid 2-related factor 2 (NRF2) with its downstream genes, was highly expressed in CD34high-enriched cells. Stable knockdown of NRF2 abolished the hyperresistance to arsenic toxicity and holoclone-forming ability of CD34high-enriched cells. Our results suggest that skin epithelial stem/progenitor cells are more resistant to arsenic toxicity than mature cells, which is associated with the high innate expression of NRF2 in skin epithelial stem/progenitor cells.
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Affiliation(s)
- Xiafang Wu
- Program of Environmental Toxicology, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Bei Yang
- Department of Histology and Embryology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
| | - Yuxin Hu
- Experimental Teaching Center, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Ru Sun
- Program of Environmental Toxicology, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Huihui Wang
- Program of Environmental Toxicology, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Jingqi Fu
- Program of Environmental Toxicology, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Yongyong Hou
- Program of Environmental Toxicology, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Jingbo Pi
- Program of Environmental Toxicology, School of Public Health, China Medical University, Shenyang, Liaoning, China
- Experimental Teaching Center, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Yuanyuan Xu
- Program of Environmental Toxicology, School of Public Health, China Medical University, Shenyang, Liaoning, China
- Experimental Teaching Center, School of Public Health, China Medical University, Shenyang, Liaoning, China
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11
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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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12
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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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13
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Morpho-mechanical intestinal remodeling in type 2 diabetic GK rats--is it related to advanced glycation end product formation? J Biomech 2013. [PMID: 23403079 DOI: 10.1016/j.] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Little is known about the mechanisms for the biomechanical remodeling in diabetes. The histomorphology, passive biomechanical properties and expression of advanced glycation end product (N epsilon-(carboxymethyl) lysine, AGE) and its receptor (RAGE) were studied in jejunal segments from 8 GK diabetic rats (GK group) and 10 age-matched normal rats (Normal group). The mechanical test was done by using a ramp distension of fluid into the jejunal segments in vitro. Circumferential stress and strain were computed from the length, diameter and pressure data and from the zero-stress state geometry. AGE and RAGE were detected by immunohistochemistry staining. Linear regression analysis was done to study association between the glucose level and AGE/RAGE expression with the histomorphometric and biomechanical parameters. The blood glucose level, the jejunal weight per length, wall thickness, wall area and layer thickness significantly increased in the GK group compared with the Normal group (P<0.05, P<0.01 and P<0.001). The opening angle and absolute values of residual strain decreased whereas the circumferential stiffness of the jejunal wall increased in the GK group (P<0.05 and P<0.01). Furthermore, stronger AGE expression in the villi and crypt and RAGE expression in the villi were found in the GK group (P<0.05 and P<0.01). Most histomorphometric and biomechanical changes were associated with blood glucose level and AGE/RAGE expression. In conclusion, histomorphometric and biomechanical remodeling occurred in type 2 diabetic GK rats. The increasing blood glucose level and the increased AGE/RAGE expression were associated with the remodeling, indicating a causal relationship.
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14
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Xu Y, Tokar EJ, Sun Y, Waalkes MP. Arsenic-transformed malignant prostate epithelia can convert noncontiguous normal stem cells into an oncogenic phenotype. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:865-71. [PMID: 22472196 PMCID: PMC3385457 DOI: 10.1289/ehp.1204987] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 03/27/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND Cancer stem cells (CSCs) are likely critical to carcinogenesis, and, like normal stem cells (NSCs), are affected by microenvironmental factors. Malignant cells release extracellular factors, modifying tumor behavior. Inorganic arsenic, a human carcinogen, is associated with an overproduction of CSCs in various model systems of carcinogenesis. OBJECTIVE We aimed to determine if NSCs are influenced by nearby arsenic-transformed malignant epithelial cells (MECs) as a possible factor in arsenic-associated CSC overabundance. METHODS Transwell noncontact co-culture allowed the study of the effects of non-contiguous, arsenic-transformed prostate MECs on the isogenic human prostate NSC line, WPE-stem. Cancer phenotype was assessed by evaluating secreted matrix metalloproteinases (MMPs), invasiveness, colony formation, and spheroid formation. Gene expression was assessed at the protein (Western blot) or mRNA (real-time reverse transcription-polymerase chain reaction) levels. RESULTS Noncontact co-culture of MECs and NSCs rapidly (≤ 3 weeks) caused hypersecretion of MMPs and marked suppression of the tumor suppressor gene PTEN in NSCs. NSCs co-cultured with MECs also showed increased invasiveness and clonogenicity and formed more free-floating spheroids and highly branched ductal-like structures in Matrigel, all typical for CSCs. MEC co-culture caused dysregulated self-renewal and differentiation-related gene expression patterns and epithelial-to-mesenchymal transition in NSCs consistent with an acquired cancer phenotype. Interleukin-6 (IL-6), a cytokine involved in tumor microenvironment control, was hypersecreted by MECs, and IL-6 exposure of NSCs resulted in the duplication of several responses in NSCs of conversion to CSCs via MEC co-culture (e.g., MMP hypersecretion, decreased PTEN). CONCLUSIONS Arsenic-transformed MECs recruit nearby NSCs into a cancer phenotype, thereby potentially increasing CSC number. This may be a factor in arsenic-induced CSC overabundance seen in multiple model systems.
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Affiliation(s)
- Yuanyuan Xu
- National Toxicology Program Laboratory, Division of the National Toxicology Program, 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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15
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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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16
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Wang X, Mandal AK, Saito H, Pulliam JF, Lee EY, Ke ZJ, Lu J, Ding S, Li L, Shelton BJ, Tucker T, Evers BM, Zhang Z, Shi X. Arsenic and chromium in drinking water promote tumorigenesis in a mouse colitis-associated colorectal cancer model and the potential mechanism is ROS-mediated Wnt/β-catenin signaling pathway. Toxicol Appl Pharmacol 2012; 262:11-21. [PMID: 22552367 DOI: 10.1016/j.taap.2012.04.014] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/09/2012] [Accepted: 04/10/2012] [Indexed: 12/19/2022]
Abstract
Exposure to carcinogenic metals, such as trivalent arsenic [As(III)] and hexavalent chromium [Cr(VI)], through drinking water is a major global public health problem and is associated with various cancers. However, the mechanism of their carcinogenicity remains unclear. In this study, we used azoxymethane/dextran sodium sulfate (AOM/DSS)-induced mouse colitis-associated colorectal cancer model to investigate their tumorigenesis. Our results demonstrate that exposure to As(III) or Cr(VI), alone or in combination, together with AOM/DSS pretreatment has a promotion effect, increasing the colorectal tumor incidence, multiplicity, size, and grade, as well as cell inflammatory response. Two-dimensional differential gel electrophoresis coupled with mass spectrometry revealed that As(III) or Cr(VI) treatment alone significantly changed the density of proteins. The expression of β-catenin and phospho-GSK was increased by treatment of carcinogenic metals alone. Concomitantly, the expression of NADPH oxidase1 (NOX1) and the level of 8-OHdG were also increased by treatment of carcinogenic metals alone. Antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, were decreased. Similarly, in an in vitro system, exposure of CRL-1807 to carcinogenic metals increased reactive oxygen species (ROS) generation, the expression of β-catenin, phospho-GSK, and NOX1. Inhibition of ROS generation by addition of SOD or catalase inhibited β-catenin expression and activity. Our study provides a new animal model to study the carcinogenicity of As(III) and Cr(VI) and suggests that As(III) and Cr(VI) promote colorectal cancer tumorigenesis, at least partly, through ROS-mediated Wnt/β-catenin signaling pathway.
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Affiliation(s)
- Xin Wang
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536, USA
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17
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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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18
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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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19
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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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20
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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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21
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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: 89] [Impact Index Per Article: 6.4] [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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22
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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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23
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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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24
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Cooper KL, Liu KJ, Hudson LG. Enhanced ROS production and redox signaling with combined arsenite and UVA exposure: contribution of NADPH oxidase. Free Radic Biol Med 2009; 47:381-8. [PMID: 19414066 PMCID: PMC2777740 DOI: 10.1016/j.freeradbiomed.2009.04.034] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 02/27/2009] [Accepted: 04/30/2009] [Indexed: 10/20/2022]
Abstract
Solar ultraviolet radiation (UVR) is the major etiological factor in skin carcinogenesis. However, in vivo studies demonstrate that mice exposed to arsenic and UVR exhibit significantly more tumors and oxidative DNA damage than animals treated with either agent alone. Interactions between arsenite and UVR in the production of reactive oxygen species (ROS) and stress-associated signaling may provide a basis for the enhanced carcinogenicity. In this study keratinocytes were pretreated with arsenite (3 microM) and then exposed to UVA (10 kJ/m(2)). We report that exposure to UVA after arsenite pretreatment enhanced ROS production, p38 MAP kinase activation, and induction of a redox-sensitive gene product, heme oxygenase-1, compared to either stimulus alone. UVR exposure resulted in rapid and transient NADPH oxidase activation, whereas the response to arsenite was more pronounced and persistent. Inhibition of NADPH oxidase decreased ROS production in arsenite-treated cells but had little impact on UVA-exposed cells. Furthermore, arsenite-induced, but not UVA-induced, p38 activation and HO-1 expression were dependent upon NADPH oxidase activity. These findings indicate differences in the mechanisms of ROS production by arsenite and UVA that may provide an underlying basis for the observed enhancement of redox-related cellular responses upon combined UVA and arsenite exposure.
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Affiliation(s)
- Karen L Cooper
- College of Pharmacy, University of New Mexico Health Sciences Center, University of New Mexico, Albuquerque, NM 87131, USA
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25
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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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26
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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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27
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Patterson TJ, Rice RH. Arsenite and insulin exhibit opposing effects on epidermal growth factor receptor and keratinocyte proliferative potential. Toxicol Appl Pharmacol 2007; 221:119-28. [PMID: 17400267 PMCID: PMC1950287 DOI: 10.1016/j.taap.2007.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Revised: 12/27/2006] [Accepted: 02/02/2007] [Indexed: 10/23/2022]
Abstract
Previous work has suggested that arsenic exposure contributes to skin carcinogenesis by preserving the proliferative potential of human epidermal keratinocytes, thereby slowing the exit of putative target stem cells into the differentiation pathway. To find a molecular basis for this action, present work has explored the influence of arsenite on keratinocyte responses to epidermal growth factor (EGF). The ability of cultured keratinocytes to found colonies upon passaging several days after confluence was preserved by arsenite and EGF in an additive fashion, but neither was effective when the receptor tyrosine kinase activity was inhibited. Arsenite prevented the loss of EGF receptor protein and phosphorylation of tyrosine 1173, preserving its capability to signal. The level of nuclear beta-catenin was higher in cells treated with arsenite and EGF in parallel to elevated colony forming ability, and expression of a dominant negative beta-catenin suppressed the increase in both colony forming ability and yield of putative stem cells induced by arsenite and EGF. As judged by expression of three genes regulated by beta-catenin, this transcription factor had substantially higher activity in the arsenite/EGF-treated cells. Trivalent antimony exhibited the same effects as arsenite. A novel finding is that insulin in the medium induced the loss of EGF receptor protein, which was largely prevented by arsenite exposure.
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Affiliation(s)
| | - Robert H. Rice
- *Correspondence to: Robert. H. Rice, Department of Environmental Toxicology, University of California, One Shields Avenue, Davis, CA 95616-8588. Tel: 530-752-5176; Fax: 530-752-3394;
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28
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Cooper KL, Liu KJ, Hudson LG. Contributions of reactive oxygen species and mitogen-activated protein kinase signaling in arsenite-stimulated hemeoxygenase-1 production. Toxicol Appl Pharmacol 2006; 218:119-27. [PMID: 17196236 DOI: 10.1016/j.taap.2006.09.020] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 09/12/2006] [Accepted: 09/21/2006] [Indexed: 11/23/2022]
Abstract
Hemeoxygenase-1 (HO-1) is an oxidative stress responsive gene upregulated by various physiological and exogenous stimuli. HO-1 has cytoprotective activities and arsenite is a potent inducer of HO-1 in many cell types and tissues, including epidermal keratinocytes. We investigated the potential contributions of reactive oxygen species (ROS) generation and mitogen-activated protein kinase (MAPK) activation to arsenite-dependent regulation of HO-1 in HaCaT cells, an immortalized human keratinocyte line. Both epidermal growth factor (EGF) and arsenite stimulated ROS production was detected by dihydroethidium (DHE) staining and fluorescence microscopy. Arsenite induced HO-1 in a time- and concentration-dependent manner, while HO-1 expression in response to EGF was modest and evident at extended time points (48-72 h). Inhibition of EGF receptor, MEK I/II or Src decreased arsenite-stimulated HO-1 expression by 20-30%. In contrast, addition of a superoxide scavenger or inhibition of p38 activity decreased the arsenite-dependent response by 80-90% suggesting that ROS and p38 are required for HO-1 induction. However, ROS generation alone was insufficient for the observed arsenite-dependent response as use of a xanthine/xanthine oxidase system to generate ROS did not produce an equivalent upregulation of HO-1. Cooperation between ERK signaling and ROS generation was demonstrated by synergistic induction of HO-1 in cells co-treated with EGF and xanthine/xanthine oxidase resulting in a response nearly equivalent to that observed with arsenite. These findings suggest that the ERK/MAPK activation is necessary but not sufficient for optimal arsenite-stimulated HO-1 induction. The robust and persistent upregulation of HO-1 may have a role in cellular adaptation to chronic arsenic exposure.
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Affiliation(s)
- Karen L Cooper
- MSC09 5360, 1 University of New Mexico Health Sciences Center, Program in Toxicology, College of Pharmacy, Albuquerque, NM 87131, USA
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29
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Lemarie A, Morzadec C, Bourdonnay E, Fardel O, Vernhet L. Human Macrophages Constitute Targets for Immunotoxic Inorganic Arsenic. THE JOURNAL OF IMMUNOLOGY 2006; 177:3019-27. [PMID: 16920938 DOI: 10.4049/jimmunol.177.5.3019] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Chronic exposure to inorganic arsenic, a widely distributed environmental contaminant, can lead to toxic effects, including immunosuppression. Owing to the established roles of human macrophages in immune defense, we determined, in the present study, whether inorganic arsenic can affect these major immune cells. Our results demonstrate that noncytotoxic concentrations of arsenic trioxide (As2O3), an inorganic trivalent form, markedly impair differentiated features of human blood monocyte-derived macrophages. First, treatment of macrophages with 1 microM As2O3 induced a rapid cell rounding and a subsequent loss of adhesion. These morphologic alterations were associated with a marked reorganization of actin cytoskeleton, which includes retraction of peripheral actin extensions and formation of a cortical actin ring. In addition, As2O3 reduced expression of various macrophagic surface markers, enhanced that of the monocytic marker CD14, and altered both endocytosis and phagocytosis; unexpectedly, exposure of macrophages to the metalloid also strongly potentiated expression of TNFalpha and IL-8 induced by LPS. Finally, like monocytes, As2O3-treated macrophages can be differentiated into dendritic-like cells. Impairment of macrophage function by As2O3 mainly resulted from activation of a RhoA/Rho-associated kinase pathway; indeed, pretreatment of macrophages with the Rho-associated kinase inhibitor Y-27632 prevented metalloid effects on cytoskeleton and phagocytosis. Moreover, As2O3 was found to increase level of the active GTP-bound form of RhoA and that of phosphorylated-Moesin, a major cytoskeleton adaptor protein involved in RhoA regulation. Taken together, our results demonstrated that human macrophages constitute sensitive targets of inorganic arsenic, which may contribute to immunotoxicity of this environmental contaminant.
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Affiliation(s)
- Anthony Lemarie
- Institut National de la Santé et de la Recherche Médicale, Unité 620, Détoxication et Réparation Tissulaire, Université de Rennes-1, France
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