title: MicroRNA-21 promotes phosphatase gene and protein kinase B/phosphatidylinositol 3-kinase expression in colorectal cancer.
abstract: OBJECTIVE
  To explore the regulatory mechanism of the target gene of microRNA-21 (miR-21), phosphatase gene (PTEN), and its downstream proteins, protein kinase B (AKT) and phosphatidylinositol 3-kinase (PI3K), in colorectal cancer (CRC) cells.
  
  
  METHODS
  Quantitative real-time PCR (qRT-PCR) and Western blot were used to detect the expression levels of miR-21 and PTEN in HCT116, HT29, Colo32 and SW480 CRC cell lines. Also, the expression levels of PTEN mRNA and its downstream proteins AKT and PI3K in HCT116 cells after downregulating miR-21 were investigated.
  
  
  RESULTS
  Comparing the miR-21 expression in CRC cells, the expression levels of miR-21 were highest in HCT116 cells, and the expression levels of miR-21 were lowest in SW480 cells. In comparing miR-21 and PTEN expression in CRC cells, we found that the protein expression levels of miR-21 and PTEN were inversely correlated (P < 0.05); when miR-21 expression was reduced, mRNA expression levels of PTEN did not significantly change (P > 0.05), but the expression levels of its protein significantly increased (P < 0.05). In comparing the levels of PTEN protein and downstream AKT and PI3K in HCT116 cells after downregulation of miR-21 expression, the levels of AKT and PI3K protein expression significantly decreased (P < 0.05).
  
  
  CONCLUSIONS
  PTEN is one of the direct target genes of miR-21. Thus, phosphatase gene and its downstream AKT and PI3K expression levels can be regulated by regulating the expression levels of miR-21, which in turn regulates the development of CRC.
authors.affiliation: Wei-Zhong Sheng, Yu-Sheng Chen, Bo Zhang, Wei-Dong Gao, Department of General Surgery, Fudan University affiliated Zhongshan Hospital, Shanghai 200032, China.
authors.forename: Wei-Zhong
authors.initials: WZ
authors.lastname: Sheng
authors.affiliation: Wei-Zhong Sheng, Yu-Sheng Chen, Bo Zhang, Wei-Dong Gao, Department of General Surgery, Fudan University affiliated Zhongshan Hospital, Shanghai 200032, China.
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Chen
authors.affiliation: Wei-Zhong Sheng, Yu-Sheng Chen, Bo Zhang, Wei-Dong Gao, Department of General Surgery, Fudan University affiliated Zhongshan Hospital, Shanghai 200032, China.
authors.forename: Chuan-Tao
authors.initials: CT
authors.lastname: Tu
authors.affiliation: Wei-Zhong Sheng, Yu-Sheng Chen, Bo Zhang, Wei-Dong Gao, Department of General Surgery, Fudan University affiliated Zhongshan Hospital, Shanghai 200032, China.
authors.forename: Juan
authors.initials: J
authors.lastname: He
authors.affiliation: Wei-Zhong Sheng, Yu-Sheng Chen, Bo Zhang, Wei-Dong Gao, Department of General Surgery, Fudan University affiliated Zhongshan Hospital, Shanghai 200032, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Wei-Zhong Sheng, Yu-Sheng Chen, Bo Zhang, Wei-Dong Gao, Department of General Surgery, Fudan University affiliated Zhongshan Hospital, Shanghai 200032, China.
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Gao
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D045325:HCT116 Cells; D019073:HT29 Cells; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D051059:PTEN Phosphohydrolase / Q000235:genetics* / Q000378:metabolism; D058539:Phosphatidylinositol 3-Kinase / Q000235:genetics* / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: Colorectal cancer; MicroRNA-21; Phosphatase and tensin homolog; Phosphatidylinositol 3-kinase; Protein kinase B