title: Transcription factor STOX1 regulates proliferation of inner ear epithelial cells via the AKT pathway.
abstract: OBJECTIVE
  Storkhead box 1 (STOX1) belongs to the forkhead family of transcription factors, and is reported to be involved in apoptosis of Caenorhabditis elegans. However, up to now the precise role of STOX1 in mammalian epithelial development has not been established. Here, we report that it plays an important role in regulation of proliferation of inner ear epithelial cells.
  
  
  METHODS
  Immunohistochemistry and reverse transcription-PCR assays were used to determine expression pattern of STOX1 in the mouse inner ear. Furthermore, its overexpression and knockdown effects on mouse inner ear epithelial cells were studied using RT-PCR, immunofluorescence, MTT assay, BrdU labelling and western blotting.
  
  
  RESULTS
  Storkhead box 1 was selectively expressed in epithelial cells, but not in stromal cells of the inner ear. Its over-expression enhanced cell proliferation and sphere formation, however, STOX1 knockdown inhibited cell proliferation and sphere formation in purified utricular epithelial cells in culture. Consistently, several cell cycle regulatory genes such as for PCNA, cyclin A and cyclin E, were up-regulated by STOX1 over-expression. Furthermore, biochemical analyses indicated that proliferation-promoting effects induced by STOX1 were mediated via phosphorylation of AKT in these cells.
  
  
  CONCLUSIONS
  Taken together, we demonstrate that STOX1 is a novel stimulatory factor for inner ear epithelial cell proliferation and might be an important target to be considered in regeneration or repair of inner ear epithelium.
authors: State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 210027, China.
authors: Xiaowei
authors: X
authors: Nie
authors: Kaiqing
authors: K
authors: Zhang
authors: Li
authors: L
authors: Wang
authors: Guangshuo
authors: G
authors: Ou
authors: He
authors: H
authors: Zhu
authors: Wei-Qiang
authors: WQ
authors: Gao
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D010766:Phosphorylation / Q000235:genetics; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering; D012444:Saccule and Utricle / Q000166:cytology* / Q000378:metabolism; D018874:Spheroids, Cellular / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D034741:RNA, Small Interfering; C000596379:STOX1 protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases