Role for the endometrial epithelial protein MFG-E8 and its receptor integrin αvβ3 in human implantation: results of an in vitro trophoblast attachment study using established human cell lines

Objective: To investigate the role of MFG-E8 and its receptor integrin avb3 in the attachment of trophoblast cells to the endometrial epithelium. Design: Experimental in vitro study. Setting: Academic center. Patient(s): None. Intervention(s): By using a well-differentiated endometrial adenocarcinoma cell line (Ishikawa cells) and choriocarcinoma human trophoblast cells (Jar cells), an in vitro assay mimicking human implantation was established. To investigate the impact of blocking MFG-E8 and integrin avb3, we pretreated the cell lines with antibodies against those proteins at different concentrations before the attachment assay. Main Outcome Measure(s): Attachment rate of Jar spheroids to the epithelial cell monolayer. Result(s): Pretreatment of Ishikawa cells with anti-MFG-E8 antibody caused a dose-dependent and significant inhibition of attachment. On the other hand, pretreatment of Jar spheroids did not result in a significant effect on the attachment rate. Pretreatment of Ishikawa cells as well as Jar spheroids with anti-integrin avb3 antibodies resulted in a dose-dependent, significant inhibition of attachment. Conclusion(s): This study showed that blocking MFG-E8 and its receptor integrin avb3 in Ishikawa cells diminishes Jar spheroid attachment. Moreover, blocking integrin avb3 in the trophoblastic cells also diminished their attachment to the Ishikawa monolayer. (c) 2014 by American Society for Reproductive Medicine.