title: Downregulation of EphA5 by promoter methylation in human prostate cancer.
abstract: BACKGROUND
  EphA5 is a member of the Eph/ephrin family and plays a critical role in the regulation of carcinogenesis. A significant reduction of EphA5 transcripts in high-grade prostate cancer tissue was shown using a transcriptomic analysis, compared to the low-grade prostate cancer tissue. As less is known about the mechanism of EphA5 downregulation and the function of EphA5, here we investigated the expression and an epigenetic change of EphA5 in prostate cancer and determined if these findings were correlated with clinicopathologic characteristics of prostate cancer.
  
  
  METHODS
  Seven prostate cell lines (RWPE-1, LNCap, LNCap-LN3, CWR22rv-1, PC-3, PC-3M-LN4, and DU145), thirty-nine BPH, twenty-two primary prostate carcinomas, twenty-three paired noncancerous and cancerous prostate tissues were examined via qRT-PCR, methylation-specific PCR, bisulfite sequencing, immunohistochemistry and western blotting. The role of EphA5 in prostate cancer cell migration and invasion was examined by wound healing and transwell assay.
  
  
  RESULTS
  Downregulation or loss of EphA5 mRNA or protein expression was detected in 28 of 45 (62.2%) prostate carcinomas, 2 of 39 (5.1%) hyperplasias, and all 6 prostate cancer cell lines. Methylation of the EphA5 promoter region was present in 32 of 45 (71.1%) carcinoma samples, 3 of 39 (7.7%) hyperplasias, and the 6 prostate cancer cell lines. Among 23 paired prostate carcinoma tissues, 16 tumor samples exhibited the hypermethylation of EphA5, and 15 of these 16 specimens (93.8%) shown the downregulation of EphA5 expression than that of their respectively matched noncancerous samples. Immunostaining analysis demonstrated that the EphA5 protein was absent or down-regulated in 10 of 13 (76.9%) available carcinoma samples, and 8 of these 10 samples (80.0%) exhibited hypermethylation. The frequency of EphA5 methylation was higher in cancer patients with an elevated Gleason score or T3-T4 staging. Following the treatment of 6 prostate cancer cell lines with 5-aza-2'-deoxycytidine, the levels of EphA5 mRNA were significantly increased. Prostate cancer cells invasion and migration were significantly suppressed by ectopic expression of EphA5 in vitro.
  
  
  CONCLUSIONS
  Our study provides evidence that EphA5 is a potential target for epigenetic silencing in primary prostate cancer and is a potentially valuable prognosis predictor and thereapeutic marker for prostate cancer.
authors.affiliation: Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical School, Fudan University, 12 Central Urumqi Road, Shanghai, 200040, China. sdjnshlb@126.com.
authors.forename: Shibao
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Pathology, Huashan Hospital North, Fudan University, Shanghai, China. zhubona@qq.com.
authors.forename: Yingfeng
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China. machunguang@sohu.com.
authors.forename: Chunguang
authors.initials: C
authors.lastname: Ma
authors.affiliation: Department of Laboratory Medicine, The people's hospital of GaoZhou, GaoZhou, China. 345273895@qq.com.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Qiu
authors.affiliation: Central Laboratory, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China. pp_dou@163.com.
authors.forename: Xinju
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical School, Fudan University, 12 Central Urumqi Road, Shanghai, 200040, China. kangban@163.com.|Central Laboratory, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China. kangban@163.com.
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Kang
authors.affiliation: Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical School, Fudan University, 12 Central Urumqi Road, Shanghai, 200040, China. wuzhiyuan126@126.com.|Central Laboratory, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China. wuzhiyuan126@126.com.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical School, Fudan University, 12 Central Urumqi Road, Shanghai, 200040, China. nausicaa.dx@live.cn.|Central Laboratory, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China. nausicaa.dx@live.cn.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.affiliation: Central Laboratory, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China. nausicaadx@163.com.
authors.forename: Xiao
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Urology, Huashan Hospital, Fudan University, Shanghai, China. zhh_888666@126.com.
authors.forename: Hu
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Pathology, Huashan Hospital North, Fudan University, Shanghai, China. rentta@163.com.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Ren
authors.affiliation: Department of Pathology, Huashan Hospital North, Fudan University, Shanghai, China. tjm195925@163.com.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical School, Fudan University, 12 Central Urumqi Road, Shanghai, 200040, China. lxy_2006000@126.com.
authors.forename: Xiangyu
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical School, Fudan University, 12 Central Urumqi Road, Shanghai, 200040, China. guanming88@yahoo.com.|Central Laboratory, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China. guanming88@yahoo.com.
authors.forename: Ming
authors.initials: M
authors.lastname: Guan
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D045744:Cell Line, Tumor; D019175:DNA Methylation / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis; D036123:Receptor, EphA5 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D012333:RNA, Messenger; C484173:EPHA5 protein, human; D036123:Receptor, EphA5