title: miR-106b is overexpressed in medulloblastomas and interacts directly with PTEN.
abstract: OBJECTIVE
  MicroRNAs (miRNAs) are an abundant group of small non-coding RNAs that have been implicated in tumorigenesis. They regulate expression of target genes by complementary base pairing. The purposes of this study were to delineate miR-106b expression in medulloblastoma (MB) and to explore its functional contributions to MB pathogenesis.
  
  
  METHODS
  We analysed expression of miR-106b in 32 MB samples by quantitative RT-PCR. We applied gain- and loss-of-function strategies to delineate the functional roles of miR-106b in MB. Luciferase reporter assay was conducted to confirm target gene of miR-106b.
  
  
  RESULTS
  Expression of miR-106b was overexpressed in MB, and was significantly associated with its host gene MCM7 (P = 0.020). Transfection of miR-106b inhibitor in MB cell lines markedly reduced cell proliferation, migration and invasion potential, and tumour sphere formation. Cell cycle analysis indicated that miR-106b inhibition induced G1 arrest and apoptosis. The cell cycle regulators, p21 and cyclin D1, and apoptotic marker cleaved PARP were differentially expressed in miR-106b inhibitor-transfected cells. PTEN was identified as a direct target gene of miR-106b. Luciferase reporter assay confirmed miR-106b directly interacted with the 3' UTR of PTEN. We found miR-106b directly targeted PTEN at transcriptional and translational levels. Immunohistochemistry revealed a trend between PTEN and miR-106b in MB tumours (P = 0.07).
  
  
  CONCLUSIONS
  These data suggested the upregulation of miR-106b in MB and the involvement of miR-106b in MB biology.
authors.affiliation: Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China.
authors.forename: Kay Ka-Wai
authors.initials: KK
authors.lastname: Li
authors.forename: Tian
authors.initials: T
authors.lastname: Xia
authors.forename: Fanny Man Ting
authors.initials: FM
authors.lastname: Ma
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Mao
authors.forename: Yin
authors.initials: Y
authors.lastname: Wang
authors.forename: Liangfu
authors.initials: L
authors.lastname: Zhou
authors.forename: Kin-Mang
authors.initials: KM
authors.lastname: Lau
authors.forename: Ho-Keung
authors.initials: HK
authors.lastname: Ng
mesh_terms: D000293:Adolescent; D000328:Adult; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002528:Cerebellar Neoplasms / Q000235:genetics* / Q000378:metabolism; D002648:Child; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008527:Medulloblastoma / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000032:analysis / Q000096:biosynthesis*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D014162:Transfection; D015854:Up-Regulation; D055815:Young Adult
chemical_list: C542541:MIRN106 microRNA, human; D035683:MicroRNAs; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: MCM7; PTEN; medulloblastoma; miR-106b; microRNA