title: Silencing of DUSP6 gene by RNAi-mediation inhibits proliferation and growth in MDA-MB-231 breast cancer cells: an in vitro study.
abstract: BACKGROUND
  Dual-specificity phosphatase 6 (DUSP6) is a negative feedback mechanism of the mitogen-activated protein (MAP) kinase superfamily (MAPK/ERK, SAPK/JNK, p38), that is associated with cellular proliferation and differentiation. It has been reported that the expression of DUSP6 in different types of breast cancer is diverse and therefore it has altered functions in various types of breast cancer. Our aim was to explore the exact function of DUSP6 in triple-negative breast cancer cells (MDA-MB-231 cell) and to determine whether the suppression of DUSP6 by small interfering RNA (siRNA) and mircroRNA (miRNA) inhibits the growth of human MDA-MB-231 breast cancer cells.
  
  
  METHODS
  DUSP6-siRNA was used to inhibit the expression of DUSP6 directly and miR-145 to inhibit the expression of DUSP6 either in MDA-MB-231 breast cancer cells and successful transfection being confirmed by Real-time PCR and Western Blotting. Down regulation of DUSP6 in MDA-MB-231 cells suppressed the cell proliferation as investigated by MTT assay and colony form assay. Transwell test and Scratch assay were conducted to investigate the migration and invasion of MDA-MB-231 cells. T-test (two-tailed) was used to compare differences between groups, and the significance level was set at P<0.05.
  
  
  RESULTS
  DUSP6 mRNA expression and protein expression were reduced after transfection with DUSP6-siRNA directly and similar trend with transfection with miR-145. The treated group with DUSP6-siRNA or miR-145 suppressed MDA-MB-231 cells proliferation, migration and invasion, and meanwhile the cells were arrested at G0/G1 phase.
  
  
  CONCLUSIONS
  DUSP6 plays a role in triple-negative breast cancer cells that might promote growth in MDA-MB-231 triple-negative breast cancer cells.
authors.affiliation: Department of General Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai 200072, China.
authors.forename: Hongming
authors.initials: H
authors.lastname: Song
authors.affiliation: Department of General Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai 200072, China.
authors.forename: Chenyang
authors.initials: C
authors.lastname: Wu
authors.affiliation: Department of General Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai 200072, China.
authors.forename: Chuankui
authors.initials: C
authors.lastname: Wei
authors.affiliation: Department of General Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai 200072, China.
authors.forename: Dengfeng
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of General Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai 200072, China.
authors.forename: Kaiyao
authors.initials: K
authors.lastname: Hua
authors.affiliation: Department of General Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai 200072, China.
authors.forename: Jialu
authors.initials: J
authors.lastname: Song
authors.affiliation: Department of General Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai 200072, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of General Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai 200072, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of General Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai 200072, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Fang
keywords: DUSP6; MDA-MB-231 cells; breast cancer; miR-145; siRNA