Epigenetic regulation of bone morphogenetic protein-6 gene expression in breast cancer cells.
Bone morphogenetic protein-6 (BMP-6) is closely correlated with tumor differentiation and skeletal metastasis. Our previous research found that BMP-6 gene expression can be activated dose-dependently by estrogen in estrogen receptor positive (ER(+)) breast cancer cell line MCF-7, but not in ER negative (ER(-)) cell line MDA-MB-231. This experiment is designed to investigate the epigenetic regulatory mechanism of the BMP-6 gene expression in breast cancer cell lines MDA-MB-231, MCF-7 and T47D with regard to the methylation status in the 5' flanking region of the human BMP-6 gene. The endogenous level of BMP-6 mRNA in ER(-) cell line MDA-MB-231 was relatively lower than that in ER(+) MCF-7 and T47D cell lines. After the treatment with 5-aza-2'-deoxycytidine (5-aza-dC, especially in the concentration of 10 microM), the BMP-6 mRNA expression in MDA-MB-231 was obviously up-regulated. However, 5-aza-dC treatment failed to regulate the expression of BMP-6 in MCF-7 and T47D cells. Using enzyme restriction PCR (MSRE-PCR), as well as bisulfite sequencing (BSG), methylation of human BMP-6 gene promoter was detected in MDA-MB-231; while in MCF-7 and T47D, BMP-6 gene promoter remained demethylated status. In 33 breast tumor specimens, promoter methylation of BMP-6 was detected by methylation-specific PCR, hypermethylation of BMP-6 was observed in ER negative cases (16 of 16 cases (100%)), while obviously lower methylation frequency were observed in ER positive cases (3 of 17 cases (18%)), indicating that BMP-6 promoter methylation status is correlated with ER status in breast cancer.
Zhang
Ming
M
Laboratory of Molecular Medicines, Medical College, Nankai University, Tianjin 300071, China.
Wang
Qing
Q
Yuan
Wei
W
Yang
Shuang
S
Wang
Xu
X
Yan
Ji-Dong
JD
Du
Jun
J
Yin
Jian
J
Gao
Song-Yuan
SY
Sun
Bao-Cun
BC
Zhu
Tian-Hui
TH
D001483:Base Sequence; D055418:Bone Morphogenetic Protein 6; D019485:Bone Morphogenetic Proteins / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D019175:DNA Methylation; D017931:DNA Primers; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics
C525816:BMP6 protein, human; D055418:Bone Morphogenetic Protein 6; D019485:Bone Morphogenetic Proteins; D017931:DNA Primers; D012333:RNA, Messenger