title: Effect of DNA methylation inhibitor on RASSF1A genes expression in non-small cell lung cancer cell line A549 and A549DDP.
abstract: BACKGROUND
  Ras association domain family 1A gene (RASSFlA) is a candidate suppressor gene, Lack of RASSF1A expression was found in lung cancer. High DNA methylation at the promoter region is the main reason for inactivating RASSF1A transcription.
  
  
  METHODS
  In this study, we examined RASSF1A's methylation status and its mRNA expression level between non-small cell lung cancer cell line A549 and anti-Cisplatin cell strain A549DDP, Furthermore, methylation of A549DDP was reversed by treatment of 5-Aza-2' - deoxycytidine (5-Aza-cdR),a DNA methyltransferase inhibitor.
  
  
  RESULTS
  We found that RASSF1A's methylation status and its mRNA expression were obvious differences between A549 and A549DDP. 5-Aza-CdR treatment remarkablly reduced cell vability of A549DDP. Moreover, 5-Aza-CdR treatment induced A549DDP cell apoptosis in a dose dependent manner with declining cell percentage in S and G2/M stage, and increasing proportion in G0/G1 stage. Cell motility was blocked in G0/G1 stage. All of A549DDP cells showed unmethylated expression, its high methylation status was reversed in a dose-dependent manner within a certain range.
  
  
  CONCLUSIONS
  The abnormal gene methylation status of RASSF1A is a molecular biomarker in lung cancer diagnosis, treatment and prognosis.
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, China. lishijun@dl.cn.
authors.forename: Duan
authors.initials: D
authors.lastname: Mengxi
authors.forename: Wang
authors.initials: W
authors.lastname: Qian
authors.forename: Wang
authors.initials: W
authors.lastname: Nan
authors.forename: Xiao
authors.initials: X
authors.lastname: Xiaoguang
authors.forename: Li
authors.initials: L
authors.lastname: Shijun