Description
Book SynopsisOver the last ten years the subject of toxicology has changed dramatically, moving from a discipline which was once firmly wedded to traditional (some might say old-fashioned) methods to one which is keen to embrace the innovative techniques emerging from the developing fields of cell culture and molecular biology.
Trade Review“Overall, we consider that this book is a useful summary of current and emerging techniques in molecular toxicology.” (BTS Newsletter, 1 March 2015)
Table of ContentsForeword xiii
Preface xv
Acknowledgements xvii
Abbreviations xix
About the Companion Website xxiii
1 Background to Molecular and Cellular Toxicology 1
1.1 What do we mean by molecular and cellular toxicology? 1
1.2 Tissues and their maintenance 2
1.2.1 Stem cells 3
1.3 Tissue damage 4
1.3.1 Consequences of tissue injury 4
1.3.2 Reversible changes in cells and tissues 6
1.3.3 Irreversible changes in cells and tissues 7
1.4 Tissue responses to injury 7
1.4.1 Oxidative stress 7
1.4.2 Necrosis and apoptosis 10
1.4.3 Neoplasia 13
1.4.4 The initiation–promotion paradigm 13
1.5 Key concepts in toxicology 23
1.5.1 Risk and hazard 23
1.5.2 Variability and uncertainty 25
1.5.3 Threshold and non-threshold dose responses 26
1.5.4 The regulatory context 28
1.5.5 Limitations of whole animal studies 29
1.5.6 Use of human tissues in toxicology 31
1.6 Summing up 33
Self-assessment questions 33
Background Reading 34
References 34
2 Individual Susceptibility to Toxic Chemicals 37
2.1 Introduction 37
2.2 Toxicogenetics and toxicogenomics 38
2.3 Genotyping and phenotyping 39
2.3.1 Genotyping 40
2.3.2 Phenotyping 43
2.3.3 Correlating genotype and phenotype 44
2.4 Polymorphic xenobiotic metabolism 45
2.4.1 Polymorphic xenobiotic metabolising enzymes 49
2.4.2 The role of xenobiotic metabolising polymorphisms in susceptibility to toxic agents 50
2.5 Study numbers and effect size 60
2.6 Recent developments 62
2.6.1 Genome-wide association studies 62
2.6.2 Collaborative programmes 64
2.7 The UK Biobank 69
2.8 Conclusions 71
Self-assessment questions 72
Background Reading 72
References 73
3 ‘Omics Techniques 79
3.1 ‘Omics and bioinformatics 79
3.2 Transcriptomics 80
3.2.1 Methodology 80
3.2.2 Proof of principle 89
3.2.3 Hepatotoxicity 91
3.2.4 Extrahepatic toxicity 96
3.3 Proteomics 97
3.3.1 Methodology 98
3.4 Metabolomics/metabonomics 101
3.4.1 MS-based metabolomics 102
3.4.2 NMR-based metabolomics 106
3.5 Integrating different types of ‘omics data 107
3.5.1 ‘Omics in drug discovery 108
3.5.2 ‘Omics profiles as biomarkers of toxicity 109
3.6 Remaining issues with ‘omics approaches 111
3.7 Conclusions 112
Self-assessment questions 113
Background Reading 113
References 113
4 In Vitro Methods for Predicting In Vivo Toxicity 117
4.1 In vitro toxicology 117
4.2 Tissue culture 117
4.2.1 Primary cell cultures 122
4.2.2 Established cell lines 125
4.3 Acute toxicity in vitro 127
4.3.1 Cytotoxicity testing 127
4.3.2 Choice of cell line 129
4.3.3 Liver 131
4.3.4 Skin 133
4.3.5 Eye 141
4.4 Repeated dose toxicity 144
4.5 Reproductive toxicity 147
4.6 Stem cell-derived systems 149
4.7 Conclusions 151
Self-assessment questions 151
Background Reading 152
References 152
5 In Vitro Methods for Absorption, Distribution, Metabolism and Excretion 159
5.1 Why study ADME in vitro? 159
5.2 Absorption 160
5.2.1 Dermal penetration 160
5.2.2 Gastrointestinal absorption 164
5.3 Distribution 171
5.3.1 Protein binding 172
5.3.2 Blood-brain barrier 172
5.3.3 Other protective barriers 176
5.4 Metabolism 176
5.4.1 Skin 177
5.4.2 Gastrointestinal tract 179
5.4.3 Liver 179
5.5 Excretion 189
5.5.1 Biliary excretion 190
5.5.2 Renal clearance 191
5.6 Conclusions 191
Self-assessment questions 192
References 192
6 In Silico Methods and Structure–Activity Relationships 199
6.1 Why in silico? 199
6.2 Predicting the ADME characteristics of xenobiotics 200
6.2.1 Absorption 200
6.2.2 Distribution 206
6.2.3 Metabolism 207
6.2.4 Excretion 212
6.3 Physiologically based biokinetic modelling 212
6.4 Toxicity 221
6.4.1 Exposure modelling 222
6.4.2 Prediction of toxicity 223
6.5 Conclusions 233
Self-assessment questions 235
References 235
7 Transgenic Animal Models for ADME and Systemic Toxicity 241
7.1 Transgenic models and their use in toxicology 241
7.2 ADME models 242
7.2.1 Nuclear receptor models 244
7.2.2 Xenobiotic metabolism models 251
7.2.3 Drug transporter models 259
7.3 Reporter models 264
7.3.1 LacZ-based models 264
7.3.2 Green fluorescent protein-based models 267
7.3.3 Luciferase-based models 268
7.3.4 Evaluation 273
7.4 Conclusions 273
Self-assessment questions 274
Background Reading 274
References 274
8 Genotoxicity and its Measurement 281
8.1 Genotoxicity testing 281
8.2 Core in vitro tests 282
8.2.1 The Ames test 282
8.2.2 In vitro gene mutation tests using mammalian cells 283
8.2.3 The in vitro chromosome aberration test 284
8.2.4 The in vitro micronucleus assay 287
8.3 Assessment of genotoxicity for regulatory purposes 291
8.4 Novel in vitro methods 292
8.4.1 GreenScreen HC 292
8.4.2 The Reconstructed Skin MicroNucleus assay 293
8.5 Novel in vivo assays for gene mutations 294
8.5.1 The Pig-A assay 294
8.5.2 In vivo assays using transgenic mouse models 295
8.6 DNA damage and its repair 300
8.6.1 DNA damage 300
8.6.2 DNA repair 305
8.7 Thresholds 308
8.8 Conclusions 310
Self-assessment questions 310
References 311
9 Oncogenes and the Identification of Human Carcinogens 317
9.1 Introduction 317
9.2 Identification of human carcinogens 317
9.2.1 The lifetime carcinogenicity bioassay 317
9.2.2 The National Toxicology Program 2-year bioassay 318
9.3 Genetic changes in cancer 321
9.3.1 Methods for detecting activated oncogenes 324
9.3.2 In vitro transformation assays 324
9.3.3 Ras oncogene activation during tumour development 326
9.3.4 Non-ras oncogenes 328
9.3.5 Evaluation 329
9.4 Non-genotoxic carcinogenesis 329
9.4.1 Non-receptor-mediated mechanisms 330
9.4.2 Receptor-mediated mechanisms 331
9.4.3 When is a genotoxic carcinogen not a genotoxic carcinogen? 333
9.5 Transgenic models for short-term carcinogenicity bioassays 335
9.5.1 RasH2 335
9.5.2 Tg.AC 337
9.5.3 p53 models 338
9.5.4 XPC−¨M−, XPA−¨M− and XPA−¨M−/p53+¨M− null mouse models 340
9.5.5 Comparative evaluation of models 340
9.5.6 Regulatory status 341
9.5.7 Limitations of the assays 343
9.5.8 Evaluation 344
9.6 Conclusions 345
Self-assessment questions 346
References 346
10 Emerging Techniques 351
10.1 What’s next? 351
10.2 Novel model organisms 351
10.2.1 The zebrafish 352
10.2.2 Evaluation 358
10.3 Less invasive methods 359
10.3.1 Use of biomarkers 359
10.3.2 Liver 359
10.3.3 Kidney 367
10.3.4 Circulating mRNA biomarkers 371
10.3.5 Evaluation 373
10.4 The systems biology approach 373
10.4.1 Systems biology in toxicology 376
10.5 Collaborative programmes 381
10.5.1 Europe 381
10.5.2 USA 383
10.5.3 Evaluation 384
10.6 Final word 385
Self-assessment questions 385
References 385
Index 391
