title: [MicroRNA-221 promotes colon carcinoma cell proliferation in vitro by inhibiting CDKN1C/p57 expression].
abstract: OBJECTIVE
  To investigate the regulatory effect of microRNA-221 (MIR221) on CDKN1C/p57 expression in colon carcinoma cells in vitro.
  
  
  METHODS
  Caco2 cells were treated with or without anti-p57-siRNA prior to the addition of pre-MIR221 or anti-MIR221. The MIR221 expression pattern was detected by real-time RT-PCR, and the mRNA and protein levels of CDKN1C/p57 expression were detected using semi-quantitative RT-PCR and Western blotting. Caco2 cell proliferation following the treatment was detected with MTT assay. CDKN1C/p57 3'-UTR fragment was amplified by PCR from the genome DNA of human colon and inserted into a luciferase reporter plasmid. The luciferase reporter plasmid construct was then transfected into Caco2 cells along with pre-MIR221 or anti-MIR221, and the luciferase activity in the transfected cells was detected.
  
  
  RESULTS
  MIR221-specific inhibitor significantly up-regulated CDKN1C/p57 protein expression in Caco2 cells (P<0.01). Anti-MIR221 could markedly inhibit Caco2 cell proliferation, and the inhibitory effect was obviously abolished by pretreatment with anti-p57-siRNA, suggesting that the inhibition was mediated by CDKN1C/p57 (P<0.01). A significant increase of luciferase activity was detected in Caco2 cells co-transfected with the luciferase reporter plasmid construct and anti-MIR221 (P<0.01).
  
  
  CONCLUSIONS
  MIR221 can interact with the target site on the 3'-UTR of CDKN1C/p57 mRNA to inhibit CDKN1C/p57 expression by post-transcriptional gene silencing to promote colon carcinoma cell proliferation, suggesting the value of MIR221 as a potential target for treatment of colon carcinoma.
authors: Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. sunkai9602@sina.com
authors: Kai
authors: K
authors: Sun
authors: Wei
authors: W
authors: Wang
authors: Shang-tong
authors: ST
authors: Lei
authors: Cheng-tang
authors: CT
authors: Wu
authors: Guo-xin
authors: GX
authors: Li
mesh_terms: D020413:3' Untranslated Regions; D018938:Caco-2 Cells; D049109:Cell Proliferation / Q000187:drug effects*; D050761:Cyclin-Dependent Kinase Inhibitor p57 / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D006801:Humans; D035683:MicroRNAs / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D050761:Cyclin-Dependent Kinase Inhibitor p57; D035683:MicroRNAs; D012333:RNA, Messenger; C493964:CDKN1C protein, human; C525709:MIR221, human