title: Knock-down of NDRG2 sensitizes cervical cancer Hela cells to cisplatin through suppressing Bcl-2 expression.
abstract: BACKGROUND
  NDRG2, a member of N-Myc downstream regulated gene family, plays some roles in cellular stress, cell differentiation and tumor suppression. We have found that NDRG2 expression in cervical cancer Hela cells increases significantly upon stimulation with cisplatin, the most popular chemotherapeutic agent currently used for the treatment of advanced cervical cancer. This interesting phenomenon drove us to evaluate the role of NDRG2 in chemosensitivity of Hela cells.
  
  
  METHODS
  In the present study, RNA interference was employed to down-regulate NDRG2 expression in Hela cells. RT-PCR and Western blot were used to detect expression of NDRG2, Bcl-2 and Bax in cancer cells. Real-time PCR was applied to detect miR-15b and miR-16 expression levels. Drug sensitivity was determined with MTT assay. Cell cloning efficiency was evaluated by Colony-forming assay. Apoptotic cells were detected with annexin V staining and flow cytometry.
  
  
  RESULTS
  In vitro drug sensitivity assay revealed that suppression of NDRG2 could sensitize Hela cells to cisplatin. Down-regulation of NDRG2 didn't influence the colony-forming ability but promoted cisplatin-induced apoptosis of Hela cells. Inhibition of NDRG2 in Hela cells was accompanied by decreased Bcl-2 protein level. However, Bcl-2 mRNA level was not changed in Hela cells with down-regulation of NDRG2. Further study indicated that miR-15b and miR-16, two microRNAs targetting Bcl-2, were significantly up-regulated in NDRG2-suppressed Hela cells.
  
  
  CONCLUSIONS
  These data suggested that down-regulation of NDRG2 could enhance sensitivity of Hela cells to cisplatin through inhibiting Bcl-2 protein expression, which might be mediated by up-regulating miR-15b and miR-16.
authors.affiliation: Department of Radiation Medicine, Fourth Military Medical University, Xi'an, China.
authors.forename: Junye
authors.initials: J
authors.lastname: Liu
authors.forename: Le
authors.initials: L
authors.lastname: Yang
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Chen
authors.forename: Kangchu
authors.initials: K
authors.lastname: Li
authors.forename: Yurong
authors.initials: Y
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Libo
authors.initials: L
authors.lastname: Yao
authors.forename: Guozhen
authors.initials: G
authors.lastname: Guo
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D015536:Down-Regulation; D019008:Drug Resistance, Neoplasm; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D025521:Tumor Suppressor Proteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C505361:MIRN15 microRNA, human; C505362:MIRN16 microRNA, human; D035683:MicroRNAs; C466228:NDRG2 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D025521:Tumor Suppressor Proteins; D002945:Cisplatin