Epigenetic and genetic alterations of the EDNRB gene in nasopharyngeal carcinoma.
BACKGROUND
Loss of heterozygosity (LOH) at 13q22 is a common event in nasopharyngeal carcinoma (NPC). EDNRB gene located at 13q22 has been demonstrated to be hypermethylated in some kinds of tumors. In the current study, we focused on the epigenetic and genetic alterations of EDNRB in NPC.


METHODS
The mRNA expression of EDNRB was detected by semiquantitative RT-PCR and real-time quantitative PCR in 49 NPC and 12 chronic nasopharyngitis biopsies. The methylation and LOH status of EDNRB were examined by methylation-specific polymerase chain reaction, microsatellite PCR and sequencing. We also examined the mRNA expression of EDNRB in four NPC cell lines after 5-aza-2'-deoxycytidine treatment.


RESULTS
EDNRB was downregulated in primary NPC tissues and NPC cell lines, and a relatively higher methylation level of EDNRB was found in NPC biopsies (84%) compared to that in chronic nasopharyngitis biopsies (42%). Treatment of NPC cell lines with 5-aza-2'-deoxycytidine activated EDNRB expression. LOH of EDNRB gene was also found at two microsatellite sites with ratios of 6.25 and 16.67% in NPC.


CONCLUSIONS
Our results suggested that EDNRB expression may be affected by aberrant promoter methylation and gene deletion and may play a role in the development of NPC.
Zhou
Liang
L
Cancer Research Institute, Xiang-Ya School of Medicine, Central South University, Changsha, PR China.
Feng
Xiangling
X
Shan
Wenjiao
W
Zhou
Wen
W
Liu
Weidong
W
Wang
Lei
L
Zhu
Bin
B
Yi
Hongmei
H
Yao
Kaitai
K
Ren
Caiping
C
D000328:Adult; D045744:Cell Line, Tumor; D002908:Chronic Disease; D015536:Down-Regulation; D044127:Epigenesis, Genetic; D005260:Female; D006801:Humans; D008297:Male; D008745:Methylation; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000378:metabolism; D010612:Pharyngitis / Q000235:genetics / Q000378:metabolism; D044023:Receptor, Endothelin B / Q000235:genetics* / Q000378:metabolism; D012220:Rhinitis / Q000235:genetics / Q000378:metabolism
D044023:Receptor, Endothelin B