title: Aberrant Hypermethylation of SALL3 with HPV Involvement Contributes to the Carcinogenesis of Cervical Cancer.
abstract: OBJECTIVE
  This study aimed to investigate the methylation status of the promoter region of spalt-like transcription factor 3 (SALL3) and the expression of SALL3 in cervical cancer to explore the function of this gene in cervical cancer carcinogenesis.
  
  
  METHODS
  The methylation status of SALL3 was detected by methylation-specific PCR, and SALL3 gene expression was assessed by real-time quantitative PCR in the cervical cancer cell lines, SiHa, HeLa and C33A, as well as in cervical cancer tissue samples (n = 23), matched pericarcinomatous tissue samples (n = 23) and normal cervix tissue samples (n = 17). MTT was used to measure the cell viability and proliferation capacity of SiHa and HeLa cells.
  
  
  RESULTS
  The SALL3 promoter was completely methylated in SiHa cells, unmethylated in C33A cells and partially methylated in HeLa cells. After treatment of SiHa and HeLa cells with 5 μM and 10 μM of 5-Azacytidine (5-Aza), respectively, the methylation level of the SALL3 promoter decreased and observed increase in the degree of unmethylation in a dose-dependent manner. Moreover, the relative expression of SALL3 mRNA increased as the concentration of 5-Aza increased in SiHa (p<0.05) and HeLa (p<0.05) cells. This above-mentioned increase in SALL3 mRNA in SiHa cells was more remarkable than that observed in HeLa cells. Cell proliferation capacity also decreased after administration of 5-Aza to SiHa and HeLa cells (p<0.05). Methylation of the SALL3 promoter was observed in 15 of 23 (65.21%) cervical cancer tissue samples, 15 of 23 (65.21%) matched pericarcinomatous tissue samples and 5 of 17 (29.41%) normal cervical tissue samples (p<0.05). SALL3 mRNA expression was significantly lower in cervical cancer and pericarcinomatous tissues compared with normal cervical tissues (p<0.05). In all cervix tissue samples, HPV infection was positively associated with hypermethylation of the promoter region of SALL3 (p<0.05, r = 0.408), and the expression of SALL3 mRNA in HPV-positive tissues was lower than that in HPV-negative tissues (p<0.05).
  
  
  CONCLUSIONS
  The aberrant hypermethylation of SALL3 together with HPV involvement inactivated its function as a tumor suppressor and contributed to carcinogenesis in cervical cancer.
authors.affiliation: Department of Gynecology and Obstetrics, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Gynecology and Obstetrics, The Affiliated Hospital of Xi'an Medical College, Xi'an 710077, China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Gynecology and Obstetrics, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Di
authors.initials: D
authors.lastname: Cao
authors.affiliation: Department of Gynecology and Obstetrics, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Minyi
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Department of Gynecology and Obstetrics, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Gynecology and Obstetrics, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Gynecology and Obstetrics, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Yang
authors.affiliation: Department of Gynecology and Obstetrics, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Meili
authors.initials: M
authors.lastname: Pei
authors.affiliation: Center of Maternal and Child Health Care, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Gynecology and Obstetrics, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Gynecology and Obstetrics, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, 277 West Yanta Road, Xi'an 710061, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Yang
mesh_terms: D015153:Blotting, Western; D063646:Carcinogenesis / Q000235:genetics / Q000473:pathology*; D016022:Case-Control Studies; D049109:Cell Proliferation; D002584:Cervix Uteri / Q000378:metabolism; D019175:DNA Methylation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D027383:Papillomaviridae / Q000472:pathogenicity*; D030361:Papillomavirus Infections / Q000150:complications* / Q000821:virology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics*; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms / Q000209:etiology* / Q000473:pathology
chemical_list: D018398:Homeodomain Proteins; D012333:RNA, Messenger; C484466:SALL3 protein, human; D014157:Transcription Factors