title: A ROS/STAT3/HIF-1α signaling cascade mediates EGF-induced TWIST1 expression and prostate cancer cell invasion.
abstract: BACKGROUND
  Epidermal growth factor (EGF) has been known to induce epithelial-mesenchymal transition (EMT) and prostate cancer cell progression. However, a detailed underlying mechanism by which EGF induces EMT and prostate cancer cell progression remained to be answered. Hypoxia-inducible factor (HIF)-1α and TWIST1 are transcription factors implicated in EMT and cancer metastasis. The purpose of this study is to determine the underlying mechanism of EGF-induced TWIST1 expression and prostate cancer invasion.
  
  
  METHODS
  siRNAs were used to silence genes. Immunoblotting, quantitative RT-PCR and immunofluorescence analysis were used to examine protein or mRNA expression. Modified Boyden chamber and invasion assay kit with Matrigel-coated inserts were used to determine prostate cancer cell migration and invasion, respectively.
  
  
  RESULTS
  We observed that EGF induced HIF-1α expression and morphological change of prostate cancer epithelial cells to mesenchymal cells. Silencing HIF-1α expression dramatically reduced EGF-induced TWIST1 expression and prostate cancer cell EMT. Conversely, transfection of the cells with HIF-1α siRNA reversed the reduced E-cadherin expression by EGF. Pretreatment of the cells with pharmacological inhibitors of reactive oxygen species [ROS, N-acetylcysteine (NAC)] and STAT3 (WP1066) but not p38 MAPK (SB203580) significantly reduced EGF-induced HIF-1α mRNA and protein expression. Further, pretreatment of the cells with NAC attenuated EGF-induced STAT3 phosphorylation. In addition, we showed that TWIST1 mediated EGF-induced N-cadherin expression, leading to prostate cancer invasion.
  
  
  CONCLUSIONS
  We demonstrate a mechanism by which EGF promotes prostate cancer cell progression through a ROS/STAT3/HIF-1α/TWIST1/N-cadherin signaling cascade, providing novel biomarkers and promising therapeutic targets for prostate cancer cell progression.
authors.affiliation: Department of Pharmacology, Myunggok Medical Research Institute, College of Medicine, Konyang University, Daejeon, Republic of Korea.
authors.forename: Kyung Hwa
authors.initials: KH
authors.lastname: Cho
authors.forename: Moon Jung
authors.initials: MJ
authors.lastname: Choi
authors.forename: Kang Jin
authors.initials: KJ
authors.lastname: Jeong
authors.forename: Jeong Jin
authors.initials: JJ
authors.lastname: Kim
authors.forename: Min Ha
authors.initials: MH
authors.lastname: Hwang
authors.forename: Shang Cheul
authors.initials: SC
authors.lastname: Shin
authors.forename: Chang Gyo
authors.initials: CG
authors.lastname: Park
authors.forename: Hoi Young
authors.initials: HY
authors.lastname: Lee
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D018450:Disease Progression; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D058750:Epithelial-Mesenchymal Transition; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D051879:Twist-Related Protein 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D015820:Cadherins; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D050796:STAT3 Transcription Factor; C103173:TWIST1 protein, human; D051879:Twist-Related Protein 1; D004815:Epidermal Growth Factor; D000111:Acetylcysteine
keywords: HIF-1α; STAT3; TWIST1; epidermal growth factor; prostate cancer invasion