title: Expression and functional significance of HtrA1 loss in endometrial cancer.
abstract: OBJECTIVE
  The purpose of this study was to determine if loss of serine protease HtrA1 in endometrial cancer will promote the invasive potential of EC cell lines.
  
  
  METHODS
  Western blot analysis and immunohistochemistry methods were used to determine HtrA1 expression in EC cell lines and primary tumors, respectively. Migration, invasion assays and in vivo xenograft experiment were performed to compare the extent of metastasis between HtrA1 expressing and HtrA1 knocked down clones.
  
  
  RESULTS
  Western blot analysis of HtrA1 in 13 EC cell lines revealed complete loss of HtrA1 expression in all seven papillary serous EC cell lines. Downregulation of HtrA1 in Hec1A and Hec1B cell lines resulted in a three- to fourfold increase in the invasive potential. Exogenous expression of HtrA1 in Ark1 and Ark2 cells resulted in three- to fourfold decrease in both invasive and migration potential of these cells. There was an increased rate of metastasis to the lungs associated with HtrA1 downregulation in Hec1B cells compared to control cells with endogenous HtrA1 expression. Enhanced expression of HtrA1 in Ark2 cells resulted in significantly less tumor nodules metastasizing to the lungs compared to parental or protease deficient (SA mutant) Ark2 cells. Immunohistochemical analysis showed 57% (105/184) of primary EC tumors had low HtrA1 expression. The association of low HtrA1 expression with high-grade endometrioid tumors was statistically significant (P = 0.016).
  
  
  CONCLUSIONS
  Collectively, these data indicate loss of HtrA1 may contribute to the aggressiveness and metastatic ability of endometrial tumors.
authors.affiliation: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Wake Forest Medical Center, Salem, North Carolina, USA.
authors.forename: Sally A
authors.initials: SA
authors.lastname: Mullany
authors.forename: Mehdi
authors.initials: M
authors.lastname: Moslemi-Kebria
authors.forename: Ramandeep
authors.initials: R
authors.lastname: Rattan
authors.forename: Ashwani
authors.initials: A
authors.lastname: Khurana
authors.forename: Amy
authors.initials: A
authors.lastname: Clayton
authors.forename: Takayo
authors.initials: T
authors.lastname: Ota
authors.forename: Andrea
authors.initials: A
authors.lastname: Mariani
authors.forename: Karl C
authors.initials: KC
authors.lastname: Podratz
authors.forename: Jeremy
authors.initials: J
authors.lastname: Chien
authors.forename: Viji
authors.initials: V
authors.lastname: Shridhar
mesh_terms: D000368:Aged; D000818:Animals; D045744:Cell Line, Tumor; D015536:Down-Regulation; D016889:Endometrial Neoplasms / Q000235:genetics / Q000378:metabolism*; D005260:Female; D000074289:High-Temperature Requirement A Serine Peptidase 1; D006801:Humans; D008175:Lung Neoplasms / Q000556:secondary; D051379:Mice; D016513:Mice, SCID; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000074289:High-Temperature Requirement A Serine Peptidase 1; C474012:HTRA1 protein, human; D012697:Serine Endopeptidases