PMID- 22672838
OWN - NLM
STAT- MEDLINE
DCOM- 20130117
LR  - 20211021
IS  - 1471-2407 (Electronic)
IS  - 1471-2407 (Linking)
VI  - 12
DP  - 2012 Jun 6
TI  - Promoter hypermethylation-induced transcriptional down-regulation of the gene 
      MYCT1 in laryngeal squamous cell carcinoma.
PG  - 219
LID - 10.1186/1471-2407-12-219 [doi]
AB  - BACKGROUND: MYCT1, previously named MTLC, is a novel candidate tumor suppressor 
      gene. MYCT1 was cloned from laryngeal squamous cell cancer (LSCC) and has been 
      found to be down-regulated in LSCC; however, the regulatory details have not been 
      fully elucidated. METHODS: Here, we sought to investigate the methylation status 
      of the CpG islands of MYCT1 and mRNA levels by bisulfite-specific PCR (BSP) based 
      on sequencing restriction enzyme digestion, reverse transcription and real-time 
      quantitative polymerase chain reaction (RQ-PCR). The function of specific sites 
      in the proximal promoter of MYCT1 in LSCC was measured by transient transfection, 
      luciferase assays, electrophoretic mobility shift assay (EMSA) and chromatin 
      immunoprecipitation assay (ChIP). RESULTS: The results suggested hypermethylation 
      of 12 CpG sites of the promoter in both laryngeal cancer tissues and the 
      laryngeal cancer line Hep-2 cell. The hypermethylation of the site CGCG (-695 to 
      -692), which has been identified as the c-Myc binding site, was identified in 
      laryngeal cancer tissues (59/73) compared to paired mucosa (13/73); in addition, 
      statistical analysis revealed that the methylation status of this site 
      significantly correlated with cancer cell differentiation(p < 0.01). The mRNA 
      level of MYCT1 increased in Hep-2 cells treated with 5-aza-C (p < 0.01). The 
      luciferase activity from mutant transfectants pGL3-MYCT1m (-852/+12, 
      mut-695-C > A, mut-693-C > G) was significantly reduced compared with the wild 
      type pGL3-MYCT1 (-852/+12), while the luciferase activity from wild transfectants 
      pGL3-MYCT1 (-852/+12) rose after 5-aza treatment in Hep-2 cells. Finally, EMSA 
      and ChIP confirmed that the methylation of the CGCG (-695 to -692) site prevented 
      c-Myc from binding of the site and demethylation treatment of the 5' flanking 
      region of MYCT1 by 5-aza induced the increased occupation of the core promoter by 
      c-Myc (p < 0.01). CONCLUSION: In summary, this study concluded that 
      hypermethylation contributed to the transcriptional down-regulation of MYCT1 and 
      could inhibit cancer cell differentiation in LSCC. DNA methylation of the CGCG 
      site (-695 to -692) of MYCT1 altered the promoter activity by interfering with 
      its binding to c-Myc in LSCC. Epigenetic therapy of reactivating MYCT1 by 5-aza 
      should be further evaluated in clinical trails of LSCC.
FAU - Yang, Min
AU  - Yang M
AD  - Department of Medical Genetics, China Medical University, Shenyang, P.R. China.
FAU - Li, Wei
AU  - Li W
FAU - Liu, Yi-Ying
AU  - Liu YY
FAU - Fu, Shuang
AU  - Fu S
FAU - Qiu, Guang-Bin
AU  - Qiu GB
FAU - Sun, Kai-Lai
AU  - Sun KL
FAU - Fu, Wei-Neng
AU  - Fu WN
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20120606
PL  - England
TA  - BMC Cancer
JT  - BMC cancer
JID - 100967800
RN  - 0 (MYCT1 protein, human)
RN  - 0 (Nuclear Proteins)
SB  - IM
MH  - Base Sequence
MH  - Carcinoma, Squamous Cell/*genetics/metabolism
MH  - Cell Line, Tumor
MH  - *DNA Methylation
MH  - Down-Regulation
MH  - *Gene Expression Regulation, Neoplastic/drug effects
MH  - Humans
MH  - Laryngeal Neoplasms/*genetics/metabolism
MH  - Nuclear Proteins/*genetics/metabolism
MH  - Nucleotide Motifs
MH  - *Promoter Regions, Genetic
MH  - Transcription, Genetic
PMC - PMC3472177
EDAT- 2012/06/08 06:00
MHDA- 2013/01/18 06:00
PMCR- 2012/06/06
CRDT- 2012/06/08 06:00
PHST- 2012/03/01 00:00 [received]
PHST- 2012/06/06 00:00 [accepted]
PHST- 2012/06/08 06:00 [entrez]
PHST- 2012/06/08 06:00 [pubmed]
PHST- 2013/01/18 06:00 [medline]
PHST- 2012/06/06 00:00 [pmc-release]
AID - 1471-2407-12-219 [pii]
AID - 10.1186/1471-2407-12-219 [doi]
PST - epublish
SO  - BMC Cancer. 2012 Jun 6;12:219. doi: 10.1186/1471-2407-12-219.