Down-regulation of hematopoiesis master regulator PU.1 via aberrant methylation in chronic myeloid leukemia.
The PU.1 transcription factor is a crucial regulator of hematopoiesis, and its expression is altered in various leukemic processes. It has been shown that expression of PU.1 is severely impaired in patients with chronic myeloid leukemia (CML), but the mechanism underlying this effect remains unknown. Through bisulfite sequencing, semi-quantitative PCR, and indirect immunofluorescence and Western blot techniques, we found aberrant methylation in the promoter region of transcription factor PU.1 in CML patients both in the chronic and blast crisis phases, as well as in the CML blast K562 cell line. Of these, several CpG sites were more highly methylated in blast crisis than chronic phase, while no methylation of these sites was observed in healthy individuals. Interestingly, CML patients achieved complete cytogenetic remission under imatinib mesylate treatment, but the aberrant methylation status of PU.1 was not reversed. Down-regulation of PU.1 expression at the mRNA and protein levels was also observed in association with aberrant methylation. Thus, for the first time, we have revealed a potential epigenetic modification of PU.1 in CML, which may be responsible for the down-regulation of PU.1. These data suggest that aberrant methylation of PU.1 may play a role in CML pathogenesis, and may therefore serve as a useful biomarker and potential target for demethylating drugs.
Department of Hematology, Xin Hua Hospital-Shanghai Jiao Tong University, School of Medicine, 1665 Kong Jiang Road, Shanghai, China.
Hui
H
Yang
Hui
H
Liang
Jing-song
JS
Yan
Rong
R
Tao
Si-guo
SG
Hao
Li-yuan
LY
Ma
D001483:Base Sequence; D018899:CpG Islands; D019175:DNA Methylation; D015536:Down-Regulation / Q000235:genetics; D015973:Gene Expression Regulation, Leukemic; D006410:Hematopoiesis / Q000235:genetics; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D000099232:Proto-Oncogene Protein Spi-1
D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1