title: Combined expression of KLK4, KLK5, KLK6, and KLK7 by ovarian cancer cells leads to decreased adhesion and paclitaxel-induced chemoresistance.
abstract: OBJECTIVE
  Chemoresistance is a critical feature of advanced ovarian cancer with only 30% of patients surviving longer than 5 years. We have previously shown that four kallikrein-related (KLK) peptidases, KLK4, KLK5, KLK6 and KLK7 (KLK4-7), are implicated in peritoneal invasion and tumour growth, but underlying mechanisms were not identified. We also reported that KLK7 overexpression confers chemoresistance to paclitaxel, and cell survival via integrins. In this study, we further explored the functional consequenses of overexpression of all four KLKs (KLK4-7) simultaneously in the ovarian cancer cell line, OV-MZ-6, and its impact on integrin expression and signalling, cell adhesion and survival as contributors to chemoresistance and metastatic progression.
  
  
  METHODS
  Quantitative gene and protein expression analyses, confocal microscopy, cell adhesion and chemosensitivity assays were performed.
  
  
  RESULTS
  Expression of α5β1/αvβ3 integrins was downregulated upon combined stable KLK4-7 overexpression in OV-MZ-6 cells. Accordingly, the adhesion of these cells to vitronectin and fibronectin, the extracellular matrix binding proteins of α5β1/αvβ3 integrins and two predominant proteins of the peritoneal matrix, was decreased. KLK4-7-transfected cells were more resistant to paclitaxel (10-100 nmol/L: 38-54%), but not to carboplatin, which was associated with decreased apoptotic stimuli. However, the KLK4-7-induced paclitaxel resistance was not blocked by the MEK1/2 inhibitor, U0126.
  
  
  CONCLUSIONS
  This study demonstrates that combined KLK4-7 expression by ovarian cancer cells promotes reduced integrin expression with consequently less cell-matrix attachment, and insensitivity to paclitaxel mediated by complex integrin and MAPK independent interactions, indicative of a malignant phenotype and disease progression suggesting a role for these KLKs in this process.
authors.affiliation: Cancer Program, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland 4059, Australia.
authors.forename: Daniela
authors.initials: D
authors.lastname: Loessner
authors.forename: Verena M C
authors.initials: VM
authors.lastname: Quent
authors.forename: Julia
authors.initials: J
authors.lastname: Kraemer
authors.forename: Eva C
authors.initials: EC
authors.lastname: Weber
authors.forename: Dietmar W
authors.initials: DW
authors.lastname: Hutmacher
authors.forename: Viktor
authors.initials: V
authors.lastname: Magdolen
authors.forename: Judith A
authors.initials: JA
authors.lastname: Clements
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology* / Q000627:therapeutic use; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016023:Integrins / Q000378:metabolism; D007610:Kallikreins / Q000235:genetics / Q000502:physiology*; D020935:MAP Kinase Signaling System; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D017239:Paclitaxel / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D016023:Integrins; C400147:KLK5 protein, human; C103551:KLK6 protein, human; C082472:KLK7 protein, human; D007610:Kallikreins; C120801:kallikrein 4; D017239:Paclitaxel