title: Downregulated miR-646 in clear cell renal carcinoma correlated with tumour metastasis by targeting the nin one binding protein (NOB1).
abstract: BACKGROUND
  Nin one binding protein (NOB1) was identified as a potential oncogene in human glioma and miR-646 plays an important role in human growth and development. However, the underlying molecular mechanisms of NOB1 in tumorigenicity and its correlation with miR-646 in renal cell carcinoma (RCC) have not been investigated.
  
  
  METHODS
  We performed bioinformatic analysis to explore miRNA targeting NOB1. The expression of NOB1 and miR-646 from 100 cases of clear cell RCC (ccRCC) and 30 cases of adjacent non-tumour tissues were detected by quantitative real-time PCR. The expression of miR-646 was correlated with NOB1 expression, tumour features and patient metastasis-free survival. The effect of overexpression of mir-646 on renal cancer cell proliferation was detected by colony formation in soft agar. Using a xenograft tumour model, we observed the in vivo tumorigenesis effect of miR-646 and NOB1.
  
  
  RESULTS
  miR-646 negatively regulated NOB1 and inhibited the proliferation and migration of renal cancer cells. There was a significant upregulation of NOB1 in ccRCC and it was further increased in metastatic cases, while miR-646 was downregulated in tumour tissues and further decreased in metastatic ccRCC. Additionally, expression of miR-646 was inversely correlated with the expression of NOB1. The downregulation of miR-646 also indicated a higher probability of developing metastasis. Most importantly, miR-646 expression was an independent predictor of ccRCC metastasis by the univariate analysis and binary logistic regression model (both P<0.05). Colony formation in soft agar and xenograft tumour model suggested that miR-646 and NOB1 are required for tumorigenesis in vitro and in vivo. Furthermore, suppression of NOB1 increased the phosphorylation of several proteins in MAPK pathway.
  
  
  CONCLUSIONS
  Downregulated miR-646 in ccRCC was associated with tumour metastasis through MAPK pathway by targeting NOB1. miR-646 and NOB1 may play an important role in the development of ccRCC.
authors.affiliation: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China.
authors.forename: W
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China.
authors.forename: M
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Nephrology, Nanjing University Affiliated Drum Tower Hospital, Nanjing, Jiangsu 210093, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China.
authors.forename: Y-F
authors.initials: YF
authors.lastname: Xu
authors.affiliation: Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL 32603, USA.
authors.forename: Y-F
authors.initials: YF
authors.lastname: Huang
authors.affiliation: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China.
authors.forename: J-P
authors.initials: JP
authors.lastname: Che
authors.affiliation: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China.
authors.forename: G-C
authors.initials: GC
authors.lastname: Wang
authors.affiliation: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China.
authors.forename: X-D
authors.initials: XD
authors.lastname: Yao
authors.affiliation: Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China.
authors.forename: J-H
authors.initials: JH
authors.lastname: Zheng
mesh_terms: D000328:Adult; D000818:Animals; D017209:Apoptosis; D063646:Carcinogenesis / Q000235:genetics; D002292:Carcinoma, Renal Cell / Q000737:chemistry / Q000235:genetics* / Q000556:secondary*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D019295:Computational Biology; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D057809:HEK293 Cells; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology*; D020935:MAP Kinase Signaling System; D008297:Male; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics*; D010766:Phosphorylation; D011379:Prognosis; D016601:RNA-Binding Proteins / Q000032:analysis / Q000235:genetics*; D014162:Transfection; D014410:Tumor Stem Cell Assay; D015854:Up-Regulation
chemical_list: C000592812:MIRN646 microRNA, human; D035683:MicroRNAs; C506664:NOB1 protein, human; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D020928:Mitogen-Activated Protein Kinases