Arsenic Research Partnership Biomarkers of Arsenic Effects on Gene Expression in Human Skin Subject Area: High-Quality Water Biomarkers of Arsenic Effects on Gene Expression in Human Skin ©2004 AwwaRF. All rights reserved. The mission of the Awwa Research Foundation (AwwaRF) is to advance the science of water to improve the quality of life. Funded primarily through annual subscription payments from over 1,000 utilities, consulting firms, and manufacturers in North America and abroad, AwwaRF sponsors research on all aspects of drinking water, including supply and resources, treatment, monitoring and analysis, distribution, management, and health effects. From its headquarters in Denver, Colorado, the AwwaRF staff directs and supports the efforts of over 800 volunteers, who are the heart of the research program. These volunteers, serving on various boards and committees, use their expertise to select and monitor research studies to benefit the entire drinking water community. Research findings are disseminated through a number of technology transfer activities, including research reports, conferences, videotape summaries, and periodicals. ©2004 AwwaRF. All rights reserved. Biomarkers of Arsenic Effects on Gene Expression in Human Skin Prepared by: Jerome Nriagu and Luda Bernstam Department of Environmental & Industrial Health School of Public Health, University of Michigan 109 Observatory Street, Ann Arbor, MI 48109-2029 Jointly sponsored by: Awwa Research Foundation 6666 West Quincy Avenue, Denver, CO 80235-3098 and Association of California Water Agencies Sacramento, CA Published by: ©2004 AwwaRF. All rights reserved. DISCLAIMER This study was jointly funded by the Awwa Research Foundation (AwwaRF) and the Association of California Water Agencies (ACWA). AwwaRF and ACWA assume no responsibility for the content of the research study reported in this publication or for the opinions or statements of fact expressed in the report. The mention of trade names for commercial products does not represent or imply the approval or endorsement of AwwaRF or ACWA. This report is presented solely for informational purposes. Copyright © 2004 by Awwa Research Foundation All Rights Reserved Printed in the U.S.A. ©2004 AwwaRF. All rights reserved. CONTENTS LIST OF TABLES.................................................................................................................... vii LIST OF FIGURES.................................................................................................................. ix FOREWORD............................................................................................................................ xiii ACKNOWLEDGMENTS........................................................................................................ xv EXECUTIVE SUMMARY...................................................................................................... xvii CHAPTER 1: INTRODUCTION AND LITERATURE REVIEW........................................ 1 Mechanisms of Arsenic Toxicity: An Overview.......................................................... 2 Morphological and Cytoskeletal Effects........................................................... 4 Genotoxic Effects.............................................................................................. 6 Effects on Chromosomes and Mitotic Apparatus............................................. 6 Generation of Oxidative Stress and Heat Shock Response by Arsenic............ 9 CHAPTER 2: MATERIAL AND METHODS........................................................................ 17 General.......................................................................................................................... 17 Uniqueness of “Lifted” Keratinocyte Cultures for Toxicity Studies................ 17 Source of Tissue................................................................................................ 17 Preparation of Cell Cultures.............................................................................. 18 Experimental Details: Exposure of Cells to Arsenic.................................................... 19 Morphological Evaluation............................................................................................ 20 Cytotoxicity Evaluation................................................................................................ 20 Permeability Assay: Water (Solvent)................................................................ 20 Permeability Assay: Arsenic (Solute)............................................................... 20 Lactate Dehydrogenase (LDH) Assay.............................................................. 21 MTS Cell Proliferation Assay........................................................................... 22 Evaluation of Toxic Effects of Arsenic on Macromolecular Biosynthesis................... 22 Evaluation of Effects of Arsenic on Programmed Cell Death...................................... 23 DNA Fragmentation Assay (TUNEL Assay)................................................... 23 Apoptosis Evaluation at the Single Cell Level (COMET Assay)..................... 23 Apoptosis Evaluation on the Chromosome Level (Telomerase Assay)........... 24 Chromosome Analysis...................................................................................... 25 Analysis of Toxic Effects of Arsenic on Signal Transduction (Western Blot)............................................................................................. 25 Genotoxicity Experiments................................................................................ 25 Inhibition of Arsenic Effect.......................................................................................... 26 Arsenate Reduction by Amino Acids........................................................................... 27 Quality Assurance Program.......................................................................................... 28 Data Analysis................................................................................................................ 29 v ©2004 AwwaRF. All rights reserved. CHAPTER 3: RESULTS......................................................................................................... 31 Morphological Studies.................................................................................................. 31 Submerged Cultures.......................................................................................... 31 Exposure to Arsenate........................................................................................ 31 Exposure to Arsenite......................................................................................... 31 Morphological Changes in Artificial Human Skin........................................... 36 Ultrastructural Changes in Artificial Skin Exposed to As(III) and As(V).................... 37 Electron Microscopy Studies............................................................................ 37 Permeation and Uptake of Water in Artificial Skin...................................................... 41 Uptake of As(III) and As(V) by the Artificial Skin...................................................... 42 Arsenate Reduction by Amino Acids........................................................................... 43 Cytotoxicity Evaluation in Submerged Cultures.......................................................... 44 LDH Assay........................................................................................................ 44 MTS Cell Viability Assay................................................................................. 47 Cytotoxicity Evaluation in Artificial Skin.................................................................... 47 Incorporation Studies in Artificial Skin............................................................ 48 DNA Synthesis................................................................................................. 50 RNA Synthesis.................................................................................................. 55 Protein Synthesis............................................................................................... 56 Effects of Arsenic on Programmed Cell Death............................................................. 57 DNA Fragmentation Assay (TUNEL Assay)................................................... 57 Apoptosis Evaluation at the Single Cell Level (COMET Assay)..................... 59 Evaluation of Apoptosis at the Chromosome Level (Telomerase Assay)........ 64 Chromosomal Damage...................................................................................... 65 Effects of Arsenic on Signal Transduction (Western Blot Method)............................. 65 Genotoxicity Experiments............................................................................................ 67 Inhibitor Experiments and Prevention of Arsenic Toxicity.......................................... 69 CHAPTER 4: DISCUSSION................................................................................................... 77 General.......................................................................................................................... 77 Permeation and Retention of Arsenic by Human Skin................................................. 77 Morphological Effects.................................................................................................. 80 Cytotoxicity of Arsenic................................................................................................. 80 Genotoxicity of Arsenic................................................................................................ 83 Chemical Inhibition of Arsenic Toxicity...................................................................... 84 CHAPTER 5: RECOMMENDATIONS................................................................................. 87 REFERENCES......................................................................................................................... 89 ABBREVIATIONS.................................................................................................................. 105 vi ©2004 AwwaRF. All rights reserved. TABLES 3.1 Absorption of As(III) by skin cultures....................................................................... 43 3.2 Percutaneous absorption of As(III) and As(V) by artificial human skins.................. 44 vii ©2004 AwwaRF. All rights reserved. ©2004 AwwaRF. All rights reserved.
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