TY - JOUR
T1 - Methylation analysis of the human multidrug resistance 1 gene in normal and leukemic hematopoietic cells
AU - Fryxell, K. B.
AU - McGee, S. B.
AU - Simoneaux, D. K.
AU - Willman, C. L.
AU - Cornwell, M. M.
N1 - Funding Information:
We thank Christina Jancke for excellent technical assistance, Reinhard Stoger for helpful advice on the bisulphite sequencing method, Tracy Stapp and Mary Kay Dolejsi for high quality sequencing, and Bernard Futscher for control primer sequences for methylation analysis of the deoxycytidine kinase gene CpG island. This research was supported by PHS grant No. R01 CA51728 (MC) and NIH grant No. U10 CA32102 (CW).
PY - 1999
Y1 - 1999
N2 - Expression of the human multidrug resistance 1 gene (MDR1), which encodes the P-glycoprotein transmembrane efflux pump, has been associated with treatment failure of some leukiemias, primarily acute myeloid leukemia (AML). To elucidate the epigenetic events associated with overexpression of MDR1 in AML, we analyzed the methylation status of a 2000 bp region within the MDR1 locus using a bisulphite genomic sequencing technique. A CpG-rich domain, approximately 1 kb in size, encompasses the promoter region, exon I, and intron I. This domain was found to be relatively unmethylated in five out of six primary and cultured human hematopoietic cells, as well as five out of six AML patient samples, independent of the MDR1 phenotype. The data suggest that the methylation status of the CpG-rich domain does not act as a 'switch' to regulate expression of the MDR1 gene. In addition, we found an upstream Alu repeat sequence to be unmethylated in three out of five cultured hematopoietic cell lines, both MDR1 expressing and non-expressing. However, analysis of primary CD8-positive T cells and AML patient samples revealed dense methylation of this region which is consistent with methylation of Alu repeat sequences observed in somatic tissues.
AB - Expression of the human multidrug resistance 1 gene (MDR1), which encodes the P-glycoprotein transmembrane efflux pump, has been associated with treatment failure of some leukiemias, primarily acute myeloid leukemia (AML). To elucidate the epigenetic events associated with overexpression of MDR1 in AML, we analyzed the methylation status of a 2000 bp region within the MDR1 locus using a bisulphite genomic sequencing technique. A CpG-rich domain, approximately 1 kb in size, encompasses the promoter region, exon I, and intron I. This domain was found to be relatively unmethylated in five out of six primary and cultured human hematopoietic cells, as well as five out of six AML patient samples, independent of the MDR1 phenotype. The data suggest that the methylation status of the CpG-rich domain does not act as a 'switch' to regulate expression of the MDR1 gene. In addition, we found an upstream Alu repeat sequence to be unmethylated in three out of five cultured hematopoietic cell lines, both MDR1 expressing and non-expressing. However, analysis of primary CD8-positive T cells and AML patient samples revealed dense methylation of this region which is consistent with methylation of Alu repeat sequences observed in somatic tissues.
KW - Acute myeloid leukemia
KW - Bisulphite sequencing
KW - CpG island
KW - MDR1
KW - Methylation
KW - Multidrug resistance
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U2 - 10.1038/sj.leu.2401424
DO - 10.1038/sj.leu.2401424
M3 - Article
C2 - 10360380
AN - SCOPUS:0032969236
SN - 0887-6924
VL - 13
SP - 910
EP - 917
JO - Leukemia
JF - Leukemia
IS - 6
ER -