TY - JOUR
T1 - Gene silencing of MIR22 in acute lymphoblastic leukaemia involves histone modifications independent of promoter DNA methylation
AU - Li, Xiaoqing
AU - Liu, Jun
AU - Zhou, Rui
AU - Huang, Shi
AU - Huang, Shiang
AU - Chen, Xian Ming
N1 - Funding Information:
The authors are grateful to the Director CSIO for allowing the publication of this paper. Thanks are also due to Department of Science and Technology, Govt of India for funding this project.
PY - 2010/1
Y1 - 2010/1
N2 - Aberrant epigenetic regulation has recently been implicated in the downregulation of tumour suppressor microRNAs (miRNAs). Histone modification and DNA methylation can have different roles in gene silencing in cancer. To investigate whether histone modifications would contribute to the dysregulation of miRNAs in acute lymphoblastic leukaemia (ALL), the effect of a histone deacetylase inhibitor, trichostatin A (TSA), on miRNA expression profile was analysed by microarray assay in a precursor B-cell ALL cell line NALM-6. A total of 10 miRNAs were downregulated and 31 were upregulated significantly following TSA treatment. Among TSA-upregulated miRNAs, MIR22 is an extronic miRNA and resides in the second exon of the non-coding transcript MGC14376. Upregulation of MIR22 transcription was found in both NALM-6 cells and primary human ALL malignant cells treated with TSA. Whereas a CpG island was identified within the promoter element of MIR22, no promoter DNA methylation was detected in these cells. In contrast, accumulation of the repressive histone marker H3K27 trimethylation (H3K27triM) was indentified around the transcriptional start point of the gene, which was reduced by TSA treatment. Thus, accumulation of H3K27triM independent of promoter DNA methylation may be a novel epigenetic mechanism for MIR22 silencing in ALL.
AB - Aberrant epigenetic regulation has recently been implicated in the downregulation of tumour suppressor microRNAs (miRNAs). Histone modification and DNA methylation can have different roles in gene silencing in cancer. To investigate whether histone modifications would contribute to the dysregulation of miRNAs in acute lymphoblastic leukaemia (ALL), the effect of a histone deacetylase inhibitor, trichostatin A (TSA), on miRNA expression profile was analysed by microarray assay in a precursor B-cell ALL cell line NALM-6. A total of 10 miRNAs were downregulated and 31 were upregulated significantly following TSA treatment. Among TSA-upregulated miRNAs, MIR22 is an extronic miRNA and resides in the second exon of the non-coding transcript MGC14376. Upregulation of MIR22 transcription was found in both NALM-6 cells and primary human ALL malignant cells treated with TSA. Whereas a CpG island was identified within the promoter element of MIR22, no promoter DNA methylation was detected in these cells. In contrast, accumulation of the repressive histone marker H3K27 trimethylation (H3K27triM) was indentified around the transcriptional start point of the gene, which was reduced by TSA treatment. Thus, accumulation of H3K27triM independent of promoter DNA methylation may be a novel epigenetic mechanism for MIR22 silencing in ALL.
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U2 - 10.1111/j.1365-2141.2009.07920.x
DO - 10.1111/j.1365-2141.2009.07920.x
M3 - Article
C2 - 19807731
AN - SCOPUS:72249107533
VL - 148
SP - 69
EP - 79
JO - British Journal of Haematology
JF - British Journal of Haematology
SN - 0007-1048
IS - 1
ER -