title: [Triptolide affect the methylation status of HL-60cells].
abstract: OBJECTIVE
  To study the effect of triptolide (TP) on the methylation status of human promyelocytic leukemia cells (HL-60) and explore a preliminary demethylation mechanism.
  
  
  METHODS
  Normal HL-60 cells as control group, the cell proliferation level of HL-60 cells was detected by MTT assay, being treated by different concentration TP (3.125, 6.25, 12.5, 25 nmol/L) for 24 h or 48 h respectively; Choosing the 3.125 nmol/L and the 6.25 nmol/L TP affected HL-60 cells for 48 h, the cell apoptosis rate and cell cycle were determined by flow cytometry, the expressions of death-associated protein kinase 1 (DAPK-1) and methyltransferase DNMT1, DNMT3B mRNA were measured by real time-PCR (RT-PCR), LINE-1, DAPK-1 genes'methylation variations were analyzed by methylation specific PCR (MSP).
  
  
  RESULTS
  Compared with control group, the different concentration TP could significantly inhibit the proliferation of HL-60 in a time-dose dependent manner (P<0.05, P<0.01). After being treated by TP for 48 h, the cell early apoptosis rate of control group and 6.250 nmol/L TP group were (2.07 ± 1.91)%, (9.77 ± 3.52)%, respectively (P<0.05); When the TP concentration increased, DAPK-1mRNA expression increased (P<0.01), DNMT1, DNMT3B mRNA expression significantly dampened (P<0.01); the promoter of LINE-1, DAPK-1 genes were hypermethylation state in the control group, after being treated by TP for 48 h, the brightness of LINE-1, DAPK-1 genes'methylation strips weakened, and the non-methylation strips enhanced all in a dose-dependent manner.
  
  
  CONCLUSIONS
  TP could down-regulate the transcriptional expression of methyltransferase DNMT1/3B genes, indirect action to reduce the degree of DAPK-1, LINE-1 genes mathylation, thus promote DAPK-1 gene expression level and inhibit the HL 60 cell growth.
authors.affiliation: Department of Hematology, the Affiliated Dayi Hospital of Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Ruijun
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Hematology, the Affiliated Dayi Hospital of Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Liangming
authors.initials: L
authors.lastname: Ma
authors.affiliation: Department of Hematology, the Affiliated Dayi Hospital of Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Yujin
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Hematology, the Affiliated Dayi Hospital of Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Bai
mesh_terms: D004248:DNA (Cytosine-5-)-Methyltransferases; D019175:DNA Methylation / Q000187:drug effects; D064550:Death-Associated Protein Kinases; D004224:Diterpenes / Q000494:pharmacology*; D004852:Epoxy Compounds / Q000494:pharmacology; D018922:HL-60 Cells; D006801:Humans; D010616:Phenanthrenes / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger; D000097584:DNA Methyltransferase 3B
chemical_list: D004248:DNA (Cytosine-5-)-Methyltransferases; D064550:Death-Associated Protein Kinases; D004224:Diterpenes; D004852:Epoxy Compounds; D010616:Phenanthrenes; D012333:RNA, Messenger; D000097584:DNA Methyltransferase 3B; C001899:triptolide