Methylation, gene expression and the chromatin connection in cancer (review)
The mechanisms by which cells regulate gene expression are often altered in tumors. Modulating aspects of the components responsible for the nuclear packaging of DNA is one means by which the cell can control transcription, either by packaging the DNA such that access to specific sites of transcription is blocked or by modifying the DNA itself to prevent transcription factor binding. One such DNA modification is the methylation of cytosines. In addition, histone acetylation status has been linked recently through a large number of studies to the regulation of gene expression. Expressed genes are located in highly acetylated chromatin. The acetylation status of nucleosomes (the basic packaging unit of chromatin), is regulated by a group of enzymes, histone acetyltransferases (HATs), and histone deacetylases (HDACs). These two elements, methylation and histone acetylation have also been linked together, whereby methylation is used to direct gene repression through a histone deacetylase complex. Methylation, HATs, and HDACs have been shown to be altered in tumors. We present an overview of the current knowledge surrounding these elements in cancer, and in the final sections describe the likelihood of alterations of the histone modifying apparatus in hepatocellular carcinoma.
Gray
S G
SG
Laboratory for Molecular Development and Tumor Biology, Department of Clinical Neuroscience, Karolinska Hospital, S-171 76 Stockholm, Sweden.
Eriksson
T
T
Ekström
T J
TJ
D000818:Animals; D002843:Chromatin / Q000235:genetics*; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009369:Neoplasms / Q000235:genetics*; D009374:Neoplasms, Experimental / Q000235:genetics
D002843:Chromatin; D004273:DNA, Neoplasm