title: Passenger strand miRNA miR-31* regulates the phenotypes of oral cancer cells by targeting RhoA.
abstract: OBJECTIVE
  MicroRNAs (miRNAs) are endogenous small non-coding RNAs that negatively regular target gene expression by RNA interference. The processing of the pre-miRNA hairpin generates a miRNA duplex, which consists of a miRNA (guide strand) and a miRNA(*) (passenger strand). miR-31 is an oncogenic miRNA and is up-regulated in oral squamous cell carcinoma (OSCC). miR-31(*) shows a high level of conservation across species and, based on this, this study hypothesized that miR-31(*) is a functional miRNA.
  
  
  METHODS
  The expression of miR-31 and miR-31* in OSCC tissues and oral cells were analyzed. Functional studies were performed on OSCC cells.
  
  
  RESULTS
  miR-31(*) is up-regulated in OSCC tissues, but its expression is less abundant than miR-31. miR-31(*) decreases the proliferation and migration of both SAS and Fadu cells. Furthermore, miR-31(*) targets the 3'UTR of RhoA and is able to down-regulate RhoA expression. Knockdown of RhoA expression is known to decrease the proliferation and migration of OSCC cells. However, up-regulation of both miR-31 and miR-31(*) by delivery of pre-mir-31 does still enhance OSCC oncogenicity.
  
  
  CONCLUSIONS
  miR-31(*) is a functional miRNA involving in regulating RhoA, and the activity of miR-31(*)'s activity seems to counteract the functions of miR-31 during OSCC tumorigenesis.
authors.affiliation: Institute of Oral Biology and Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Kuo-Wei
authors.initials: KW
authors.lastname: Chang
authors.forename: Shou-Yen
authors.initials: SY
authors.lastname: Kao
authors.forename: Yi-Hsuan
authors.initials: YH
authors.lastname: Wu
authors.forename: Meng-Miao
authors.initials: MM
authors.lastname: Tsai
authors.forename: Hsi-Feng
authors.initials: HF
authors.lastname: Tu
authors.forename: Chung-Ji
authors.initials: CJ
authors.lastname: Liu
authors.forename: Mann-Tin
authors.initials: MT
authors.lastname: Lui
authors.forename: Shu-Chun
authors.initials: SC
authors.lastname: Lin
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D017124:Conserved Sequence / Q000235:genetics; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics*; D009062:Mouth Neoplasms / Q000235:genetics*; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D015854:Up-Regulation; D020742:rhoA GTP-Binding Protein / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; C534612:MIRN31 microRNA, human; D035683:MicroRNAs; D034741:RNA, Small Interfering; C066737:RHOA protein, human; D020742:rhoA GTP-Binding Protein