title: Serine protease inhibitor Kazal type 1 promotes epithelial-mesenchymal transition through EGFR signaling pathway in prostate cancer.
abstract: BACKGROUND
  Overexpression of serine protease inhibitor Kazal type 1 (SPINK1) defines an aggressive molecular subtype of ETS fusion-negative prostate cancer (PCa) patients in western countries. However, how SPINK1 contributes to PCa invasion and metastasis is largely unknown.
  
  
  METHODS
  Fluorescence in situ hybridization and immunohistochemistry were utilized to detect ERG rearrangement, SPINK1 expression, and EGFR aberrations in a cohort of 211 PCa patients with radical prostatectomy. Real-time quantitative PCR and Western blotting were used to study the transcript and protein expression levels. Cellular distribution of E-cadherin and vimentin were observed by immunofluorescence. Cellular function was evaluated by siRNA, transwell, and wound healing assay, respectively.
  
  
  RESULTS
  SPINK1-induced Epithelial-mesenchymal transition (EMT) in benign prostate RWPE cells, manifested by acquisition of mesenchymal morphology, alternation of EMT markers as well as migration and invasion capabilities. Knockdown of SPINK1 in 22RV1 PCa cells results in up-regulation of E-cadherin and down-regulation of vimentin. SPINK1-induced EMT is mediated by EGFR, in which MAPK/MEK/ERK pathway is mainly involved. Connective tissue growth factor (CTGF) might be an important down-stream molecule of SPINK1-EGFR axis. Clinically, SPINK1 and EGFR were significantly co-overexpressed in a cohort of Chinese PCa patients (n > 200). SPINK1 is an unfavorable prognostic factor in Chinese PCas (P = 0.025).
  
  
  CONCLUSIONS
  These findings suggest that SPINK1 promotes EMT through EGFR signaling pathway in PCa and SPINK1 could be a new prognostic marker in Chinese PCas.
authors.affiliation: Department of Pathology, Shandong University Medical School, Jinan, China.
authors.forename: Chunni
authors.initials: C
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Bo
authors.initials: B
authors.lastname: Su
authors.forename: Ning
authors.initials: N
authors.lastname: Lu
authors.forename: Jingjing
authors.initials: J
authors.lastname: Song
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Yang
authors.forename: Weiwei
authors.initials: W
authors.lastname: Fu
authors.forename: Weiwei
authors.initials: W
authors.lastname: Tan
authors.forename: Bo
authors.initials: B
authors.lastname: Han
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism / Q000494:pharmacology*; D045744:Cell Line, Tumor; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects / Q000502:physiology*; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D014359:Trypsin Inhibitor, Kazal Pancreatic; D014746:Vimentin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D002352:Carrier Proteins; C486642:SPINK1 protein, human; D014746:Vimentin; D014359:Trypsin Inhibitor, Kazal Pancreatic; D066246:ErbB Receptors
keywords: CTGF; EGFR; SPINK1; epithelial-mesenchymal transition; prostate cancer