title: Epigenetic interplay between histone modifications and DNA methylation in gene silencing.
abstract: Knowledge on heritable changes in gene expression that result from epigenetic events is of increasing relevance in the development of strategies for prevention, early diagnosis and treatment of cancer. Histone acetylation and DNA methylation are epigenetic modifications whose patterns can be regarded as heritable marks that ensure accurate transmission of the chromatin states and gene expression profiles over many cell generations. Importantly, patterns and levels of DNA methylation and histone acetylation are profoundly altered in human cancers. Accumulating evidence suggests that an epigenetic cross-talk, i.e. interplay between DNA methylation and histone acetylation, may be involved in the process of gene transcription and aberrant gene silencing in tumours. Although the molecular mechanism of gene activation is relatively well understood, the hierarchical order of events and dependencies leading to gene silencing in the course of cancer development remain largely unknown. While some studies suggest that DNA methylation patterns guide histone modifications (including histone acetylation and methylation) during gene silencing, other studies argue that DNA methylation takes its cues primarily from histone modification states. In this review, we summarize current knowledge on the interplay between DNA methylation and histone modifications during gene silencing and its importance in the integration of environmental and intrinsic stimuli in the control of gene expression. We also discuss the importance of an epigenetic cross-talk in the protection against genetic changes in response to environmental genotoxins as well as the implication for cancer therapy and prevention.
authors.affiliation: Epigenetics Group, International Agency for Research on Cancer (IARC), 150 Cours Albert-Thomas, F-69008 Lyon, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Vaissière
authors.forename: Carla
authors.initials: C
authors.lastname: Sawan
authors.forename: Zdenko
authors.initials: Z
authors.lastname: Herceg
mesh_terms: D000107:Acetylation; D042002:Chromatin Assembly and Disassembly; D019175:DNA Methylation; D004785:Environmental Pollutants / Q000494:pharmacology; D044127:Epigenesis, Genetic; D005786:Gene Expression Regulation; D020868:Gene Silencing; D006657:Histones / Q000378:metabolism*; D006801:Humans; D009153:Mutagens / Q000494:pharmacology; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D004785:Environmental Pollutants; D006657:Histones; D009153:Mutagens