title: [Effects of 5-Aza-2-deoxycytidine on DNA methylation of anti-oncogenes in non-small cell lung cancer cells].
abstract: OBJECTIVE
  To observe the expression of SFRP1 gene methylation in non-small cell lung cancer (NSCLC), and study the effect of 5-Aza-2-deoxycytidine (5-Aza-CdR) on DNA methylation and expression of SFRP1, p16 and MGMT genes in the human lung cancer cell line SPC-A-1 cells.
  
  
  METHODS
  SP immunohistochemistry and methylation-specific PCR were used to detect the SFRP1 methylation in 60 NSCLC cases, and 21 cases of benign lung diseases were used as control group. SPC-A-1 cells were cultured and treated with 5-Aza-CdR. The promoter methylation status of SFRP1, p16 and MGMT genes were detected by methylation-specific polymerase (MSP) chain reaction, and mRNAs were detected by real-time PCR.
  
  
  RESULTS
  The positive rate of SFRP1 gene methylation in NSCLC was significantly higher than that in normal lung tissue (58.3% vs. 14.3%; χ(2) = 12.118, P = 0.001). SFRP1 gene methylation was closely correlated with lymph node metastasis and degree of differentiation in NSCLC (P < 0.05). SFRP1 protein expression was correlated with clinical stage, degree of differentiation and lymph node metastasis in NSCLC (P < 0.05). The positive expression of SFRP1 protein in 30 cases of NSCLC tissue containing SFRP1 gene methylation was significantly higher than that in non-methylated NSCLC (68.6% vs. 24.0%; χ(2) = 9.613, P = 0.002). SFRP1 gene methylation was closely correlated with SFRP1 gene protein expression in NSCLC (P < 0.05). Negative expression of SFRP1 protein was correlated with the differentiation, clinical stage, and lymph node metastasis in NSCLC (all P < 0.05). Without 5-Aza-CdR treatment, the expressions of methylation of SFRP1, p16 and MGMT genes and their mRNA were low. After 5-Aza-CdR treatment at different concentrations, their expressions were significantly elevated (all P < 0.05).
  
  
  CONCLUSIONS
  SFRP1 gene methylation is closely associated with carcinogenesis and development of NSCLC. 5-Aza-CdR may reverse the methylation of SFRP1, p16 and MGMT genes, and facilitate the re-expression of the anti-oncogenes.
authors.affiliation: Department of Thoracic Surgery, First Affiliated Hospital of Anhui Medical University, Hefei 230022, China.
authors.forename: Han-lin
authors.initials: HL
authors.lastname: Fang
authors.forename: Zai-cheng
authors.initials: ZC
authors.lastname: Yu
authors.forename: Hui-bin
authors.initials: HB
authors.lastname: Zhu
authors.forename: Yong-tang
authors.initials: YT
authors.lastname: Jin
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism / Q000473:pathology*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D015254:DNA Modification Methylases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism; D000077209:Decitabine; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009367:Neoplasm Staging; D012333:RNA, Messenger / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism; D000094742:Secreted Frizzled-Related Proteins
chemical_list: D000964:Antimetabolites, Antineoplastic; D001374:Azacitidine; D019941:Cyclin-Dependent Kinase Inhibitor p16; D015254:DNA Modification Methylases; D045643:DNA Repair Enzymes; D000077209:Decitabine; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; C117636:SFRP1 protein, human; D000094742:Secreted Frizzled-Related Proteins; C515491:MGMT protein, human