title: Mesenchymal-to-epithelial transition determinants as characteristics of ovarian carcinoma effusions.
abstract: The present study investigated the intracellular regulation of E-cadherin in ovarian carcinoma. E-cadherin expression and regulation by Snail and Pak1 were studied in ES-2 and OVCAR-3 ovarian cancer cells in vitro. Twist1, Zeb1 and Vimentin mRNA expression and HIF-1alpha protein expression were analyzed in 80 and 189 clinical specimens, respectively. OVCAR-3 cells incubated with an anti-E-cadherin antibody formed smaller and looser spheroids compared to controls. Snail silencing using Small Hairpin RNA in ES-2 cells reduced invasion and MMP-2 activity, with unaltered cellular morphology. Using dominant negative (DN) and constitutively active (CA) Pak1 constructs, we found that DN Pak1 ES-2 and OVCAR-3 clones had reduced attachment to matrix proteins, invasion and MMP-2 activity compared to CA and wild-type cells. DN Pak1 ES-2 cells also bound less to LP9 mesothelial cells. DN Pak1 OVCAR-3 cells had lower Vimentin levels. Snail expression was lower in cultured effusions compared to primary carcinomas, and was cytoplasmic rather than nuclear. Twist1 (P < 0.001), Zeb1 (P = 0.003) and Vimentin (P = 0.03) mRNA expression was significantly higher in solid metastases compared to primary carcinomas and effusions. HIF-1alpha protein expression was lower in effusions compared to primary carcinomas and solid metastases (P = 0.033). Our data suggest that the previously reported E-cadherin re-expression in ovarian carcinoma effusions is regulated by Pak1. The transient nature of E-cadherin expression during ovarian carcinoma progression is probably the result of partial epithelial-to-mesenchymal transition (EMT) and the reverse process of mesenchymal-to-epithelial-like transition (MET). Expression of the EMT-related molecules Twist, Zeb1, Vimentin and HIF-1alpha is anatomic site-dependent in ovarian carcinoma.
authors.affiliation: Institute of Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Sivan
authors.initials: S
authors.lastname: Elloul
authors.forename: Olga
authors.initials: O
authors.lastname: Vaksman
authors.forename: Helene Tuft
authors.initials: HT
authors.lastname: Stavnes
authors.forename: Claes G
authors.initials: CG
authors.lastname: Trope
authors.forename: Ben
authors.initials: B
authors.lastname: Davidson
authors.forename: Reuven
authors.initials: R
authors.lastname: Reich
mesh_terms: D001483:Base Sequence; D015820:Cadherins / Q000378:metabolism; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D004848:Epithelium / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics / Q000502:physiology; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism* / Q000473:pathology; D009687:Nuclear Proteins / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D016066:Pleural Effusion, Malignant / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D051879:Twist-Related Protein 1 / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism*; D000071799:Zinc Finger E-box-Binding Homeobox 1; D054462:p21-Activated Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D015820:Cadherins; C497442:HIF1A protein, human; D018398:Homeodomain Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D012333:RNA, Messenger; D000071250:Snail Family Transcription Factors; C103173:TWIST1 protein, human; D014157:Transcription Factors; D051879:Twist-Related Protein 1; D014746:Vimentin; C486307:ZEB1 protein, human; D000071799:Zinc Finger E-box-Binding Homeobox 1; C515903:PAK1 protein, human; D054462:p21-Activated Kinases