title: Characterization of cell polarity and epithelial junctions in the choriocarcinoma cell line, JAR.
abstract: In the placenta the trophoblast cell layer separates maternal and fetal circulations and is involved in the active transport of selected substances across this barrier. We have used the JAR choriocarcinoma cell line to study aspects of trophoblast membrane transport. To determine whether JAR cells could be used in studies of vectorial transepithelial transport it was necessary to determine whether these cells were polarized and assembled tight junctions. In the present study we investigated JAR cells using a range of markers for specific cell surface domains combined with confocal laser scanning microscopy. Freshly isolated cells initially formed a confluent epithelial monolayer with recruitment of a tight junction-associated protein, ZO-1, and a cell adhesion molecule, E-cadherin, to the surface at sites of cell-cell contact. They did not, however, display cell surface polarization, as NaK-ATPase was not segregated in the basolateral domain, and a differentiated apical cell surface was not assembled. The monolayer stage was also unstable, as continued proliferation resulted in the formation of multilayered aggregates where ZO-1 and E-cadherin were lost from the cell surface. These results suggest that the JAR cell line is unlikely to be a suitable model for studies of transepithelial transport in the placenta.
authors.affiliation: Conjoint Endocrine Laboratory, Royal Brisbane Hospital, Qld, Australia.
authors.forename: A M
authors.initials: AM
authors.lastname: Mitchell
authors.forename: A S
authors.initials: AS
authors.lastname: Yap
authors.forename: E J
authors.initials: EJ
authors.lastname: Payne
authors.forename: S W
authors.initials: SW
authors.lastname: Manley
authors.forename: R H
authors.initials: RH
authors.lastname: Mortimer
mesh_terms: D001692:Biological Transport; D015820:Cadherins / Q000032:analysis; D002455:Cell Division; D016764:Cell Polarity; D002822:Choriocarcinoma; D004848:Epithelium / Q000378:metabolism / Q000648:ultrastructure; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives; D006801:Humans; D007365:Intercellular Junctions; D007834:Lasers; D008565:Membrane Proteins / Q000032:analysis; D018613:Microscopy, Confocal; D010750:Phosphoproteins / Q000032:analysis; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis; D014327:Trophoblasts / Q000378:metabolism* / Q000648:ultrastructure; D014407:Tumor Cells, Cultured; D014909:Wheat Germ Agglutinins; D062826:Zonula Occludens-1 Protein
chemical_list: D015820:Cadherins; D008565:Membrane Proteins; D010750:Phosphoproteins; C569042:TJP1 protein, human; D014909:Wheat Germ Agglutinins; D062826:Zonula Occludens-1 Protein; C047939:fluorescein isothiocyanate-wheat germ agglutinin; D000254:Sodium-Potassium-Exchanging ATPase; D016650:Fluorescein-5-isothiocyanate