title: Apoptosis signal-regulating kinase 1 is associated with the effect of claudin-6 in breast cancer.
abstract: BACKGROUND
  Previous studies have demonstrated that claudin-6 functions as a cancer suppressor in human MCF-7 breast cancer cells. The growth inhibitory effect could be attributed to inhibition of cell proliferation and induction of apoptosis. The purpose of the current study was to examine the involvement of apoptosis signal-regulating kinase 1 (ASK1) in the anticancer effect of claudin-6.
  
  
  METHODS
  Immunohistochemical analysis was performed to evaluate the ASK1 protein expression and the correlation between ASK1, claudin-6 and clinicopathological features in 85 samples of breast invasive ductal carcinomas (IDC). Western blotting and RT-PCR was carried out to examine the expression of ASK1 and claudin-6 in MCF-7 cell clones transfected with claudin-6.
  
  
  RESULTS
  Immunohistochemical analysis showed that ASK1 expression was significantly related with that of claudin-6 in breast invasive ductal carcinomas (P < 0.05). In addition, a positive correlation between ASK1 and C-erb B 2 protein expression was identified (P < 0.05). Western blotting and RT-PCR consistently revealed that the level of ASK1 protein and mRNA was upregulated in MCF-7 cell clones transfected with claudin-6.
  
  
  CONCLUSIONS
  Our data suggests, for the first time, that the ASK1 signal may play a positive role in the inhibitory effect of claudin-6 in breast cancer.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1200314318763661.
authors.affiliation: The Key Laboratory of Pathobiology, Ministry of Education, Beyuthune Medical College, Jilin University, Changchun, Jilin, China.
authors.forename: Yaxiong
authors.initials: Y
authors.lastname: Guo
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Xu
authors.forename: Zhijing
authors.initials: Z
authors.lastname: Liu
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Zhang
authors.forename: Liping
authors.initials: L
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.forename: Yunpeng
authors.initials: Y
authors.lastname: Liu
authors.forename: Chengshi
authors.initials: C
authors.lastname: Quan
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D057167:Claudins / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D048848:MAP Kinase Kinase Kinase 5 / Q000235:genetics / Q000378:metabolism*; D061986:MCF-7 Cells; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014162:Transfection
chemical_list: D057167:Claudins; D048848:MAP Kinase Kinase Kinase 5; D012333:RNA, Messenger; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human; C482858:MAP3K5 protein, human; C122101:claudin 6