title: MiR-21 suppresses the anticancer activities of curcumin by targeting PTEN gene in human non-small cell lung cancer A549 cells.
abstract: OBJECTIVE
  Curcumin, a natural phytochemical, exhibits potent anticancer activities. Here, we sought to determine the molecular mechanisms underlying the cytotoxic effects of curcumin against human non-small cell lung cancer (NSCLC) cells.
  
  
  METHODS
  MTT assay and annexin-V/PI staining were used to analyze the effects of curcumin on the proliferation and apoptosis of A549 cells. The expression of microRNA-21 in curcumin-treated A549 cells was measured by quantitative real-time polymerase chain reaction assay. The protein level of phosphatase and tensin homolog (PTEN), a putative target of microRNA-21, was determined by Western blot analysis. Transfection of A549 cells with microRNA-21 mimic or PTEN small interfering RNA was performed to modulate the expression of microRNA-21 and PTEN under the treatment of curcumin.
  
  
  RESULTS
  Curcumin at 20-40 μM inhibited cell proliferation and induced apoptosis in A549 cells. Curcumin treatment produced a dose-dependent and significant (P < 0.05) suppression of microRNA-21 expression, compared to untreated A549 cells. Moreover, the protein level of PTEN, a putative target of microRNA-21, was significantly elevated in curcumin-treated A549 cells, as determined by Western blot analysis. Transfection of A549 cells with microRNA-21 mimic or PTEN small interfering RNA significantly (P < 0.05) reversed the growth suppression and apoptosis induction by curcumin, compared to corresponding controls.
  
  
  CONCLUSIONS
  Our data suggest a novel molecular mechanism in which inhibition of microRNA-21 and upregulation of PTEN mediate the anticancer activities of curcumin in NSCLC cells. Suppression of microRNA-21 may thus have therapeutic benefits against this malignancy.
authors.affiliation: Department of Respiratory Diseases, The First Affiliated Hospital of Nanchang University, Nanchang, People's Republic of China.
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.forename: W
authors.initials: W
authors.lastname: Bai
authors.forename: W
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003474:Curcumin / Q000494:pharmacology*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D014162:Transfection
chemical_list: D000970:Antineoplastic Agents; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; D003474:Curcumin