title: Clusterin plays an important role in clear renal cell cancer metastasis.
abstract: OBJECTIVE
  Clusterin (CLU) is implicated in regulating clear renal cell carcinoma (CRCC) progression and metastasis, yet the mechanisms are not elucidated. In the present study, we explored the potential role of CLU in CRCC metastasis.
  
  
  METHODS
  Levels of CLU mRNA and CLU protein were measured by RT-PCR and immunohistochemistry analysis in 22 CRCC with metastasis and 22 without metastasis and 22 samples of normal kidney tissue. After CLU silencing and re-expression, the migration and invasion in vitro and in vivo of Caki-2 cells were determined by wound healing assay, transwell migration assay and pulmonary nodule assay, respectively. The expression of pERK1/2 and MMP-9 were detected by RT-PCR and Western blot assay.
  
  
  RESULTS
  We found a significant increase of CLU and CLU mRNA expression in CRCC, and the expression of CLU is strongly correlated in patients with metastatic disease. We discovered that CLU-rich Caki-2 cells displayed higher invasive ability which prompted us to investigate if CLU silencing could reduce the migration and invasion in Caki-2 cells. Compared with the vector-transfected cells, CLU knocked-down (CLUi) cells showed reduced migration and invasion in vitro, as well as decreased metastatic potential in experimental metastasis. Re-expression of CLU in CLUi cells restored the invasive phenotypes. We found that MMP-9 was downregulated in CLUi cells. We also discovered that levels of activated ERK1/2 correlated with the rich expression of CLU and MMP-9.
  
  
  CONCLUSIONS
  Our data suggest that CLU may regulate aggressive behavior of human CRCC cells through modulating ERK1/2 signaling and MMP-9 expression.
authors.affiliation: Department of Urology, The Affiliated Hospital of Medical College, Qingdao University, Qingdao, PR China.
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Luo
authors.forename: Dahai
authors.initials: D
authors.lastname: Dong
authors.forename: Qinchao
authors.initials: Q
authors.lastname: Yu
authors.forename: Kai
authors.initials: K
authors.lastname: Zhao
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D002292:Carcinoma, Renal Cell / Q000235:genetics / Q000378:metabolism* / Q000556:secondary; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D002465:Cell Movement; D051152:Clusterin / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000556:secondary; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D009361:Neoplasm Invasiveness; D010641:Phenotype; D016133:Polymerase Chain Reaction; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; C495242:CLU protein, human; D051152:Clusterin; D012333:RNA, Messenger; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9