Microarray analysis of epigenetic silencing of gene expression in the KAS-6/1 multiple myeloma cell line.
The epigenetic control of gene transcription in cancer has been the theme of many recent studies and therapeutic approaches. Carcinogenesis is frequently associated with hypermethylation and consequent down-regulation of genes that prevent cancer, e.g., those that control cell proliferation and apoptosis. We used the demethylating drug zebularine to induce changes in DNA methylation, then examined patterns of gene expression using cDNA array analysis and Restriction Landmark Genomic Scanning followed by RNase protection assay and reverse transcription-PCR to confirm the results. Microarray studies revealed that many genes were epigenetically regulated by methylation. We concluded that methylation decreased the expression of, or silenced, several genes, contributing to the growth and survival of multiple myeloma cells. For example, a number of genes (BAD, BAK, BIK, and BAX) involved in apoptosis were found to be suppressed by methylation. Sequenced methylation-regulated DNA fragments identified by Restriction Landmark Genomic Scanning were found to contain CpG islands, and some corresponded to promoters of genes that were regulated by methylation. We also observed that after the removal of the demethylating drug, the addition of interleukin 6 restored CpG methylation and re-established previously silenced gene patterns, thus implicating a novel role of interleukin 6 in processes regulating epigenetic gene repression and carcinogenesis.
Pompeia
Celine
C
Laboratory of Molecular Immunoregulation, National Cancer Institute-Frederick Cancer Research and Development Center, Frederick, Maryland 21702, USA.
Hodge
David R
DR
Plass
Christoph
C
Wu
Yue-Zhong
YZ
Marquez
Victor E
VE
Kelley
James A
JA
Farrar
William L
WL
D045744:Cell Line, Tumor; D003562:Cytidine / Q000031:analogs & derivatives; D019175:DNA Methylation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D015894:Genome, Human; D006801:Humans; D009101:Multiple Myeloma / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D011741:Pyrimidine Nucleosides / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012260:Ribonucleases / Q000378:metabolism
D011741:Pyrimidine Nucleosides; D003562:Cytidine; C009131:pyrimidin-2-one beta-ribofuranoside; D012260:Ribonucleases