title: [Expression Analysis and Epigenetics of MicroRNA let-7b in Acute Lymphoblastic Leukemia].
abstract: OBJECTIVE
  To study the expression and its mechamisms of microRNA let-7b in adult acute lymphoblastic leukemia (ALL), so as to provide the basis for searching a new targeted therapy.
  
  
  METHODS
  Firstly, methylation-specific polymerase chain reaction (MSP) was used to analyze the methylation status of CpG islands in microRNA let-7b promoter of bone marrow mononuclear cells in the patients with ALL and patients with non-hematologic malignancies as control, the real-time fluorescence quantitative polymerase chain reaction (qPCR) was used to detect the expression levels of microRNA let-7b in this 2 groups; and then 5-aza-2'-deoxycytidine (5-Aza-dC, DAC) was used to treat ALL cell line MOLT-4; after drug treatment, MSP was used to analyze the methylation status of the CpG islands in microRNA let-7b promoter; the qPCR was used to detect the expression levels of microRNA let-7b, and further explore the regulatory mechanism of microRNA let-7b expression.
  
  
  RESULTS
  Hypermethylation of CpG islands in microRNA let-7b promoter in ALL patients was significantly higher than that in patients with non-hematologic malignancies, and the relative expression level of microRNA let-7b was significantly reduced in ALL patients; 5-aza-dC could significantly inhibit the growth of MOLT-4 cells and arrest the cells in G1 phase, thus biosynthesis of RNA and protein was suppressed, and the apoptosis was promoted, meanwhile, 5-Aza-dC could increase the expression of microRNA let-7b.
  
  
  CONCLUSIONS
  In the patients with ALL, the expression of microRNA let-7b is regulated by methylation of CpG islands in the region of genomic promoter. The microRNA let-7b may act as a tumor suppressor, whose low expression is involved in ALL development, indicating the microRNA let-7b may become a new therapeutic target for ALL.
authors.affiliation: Department of Hematology, The Quanzhou First Hospital Affiliated to Fujian Medical University, Quanzhou 362000, Fujian Province, China. E-mail: 15377994910@163.com.
authors.forename: Wen-Qian
authors.initials: WQ
authors.lastname: Xu
authors.affiliation: Department of Hematology, The Quanzhou First Hospital Affiliated to Fujian Medical University, Quanzhou 362000, Fujian Province, China.
authors.forename: Yuan-Mao
authors.initials: YM
authors.lastname: Huang
authors.affiliation: Department of Hematology, The Quanzhou First Hospital Affiliated to Fujian Medical University, Quanzhou 362000, Fujian Province, China.
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Xiao
mesh_terms: D017209:Apoptosis; D001374:Azacitidine / Q000031:analogs & derivatives; D018899:CpG Islands; D019175:DNA Methylation; D000077209:Decitabine; D044127:Epigenesis, Genetic; D006801:Humans; D035683:MicroRNAs; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma; D011401:Promoter Regions, Genetic; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D035683:MicroRNAs; C487931:mirnlet7 microRNA, human; D000077209:Decitabine; D001374:Azacitidine