Interaction of Trophoblast and of Tumor Cells with Endometrial Fragments in Organ Culture

23. Annual Meeting of the Cell, Tissue and Organ Culture Study Group (C.T.O.C.), Kollekolle, 1985 INTERACTION OF TROPHOBLAST AND OF TUMOR CELLS WITH ENDOMETRIAL FRAGMENTS IN ORGAN CULTURE H.-W. Denker, A. Donner, H.-P. Hohn Abteilung Anatomie der RWTH, Melatener Straße 211, D-5100 Aachen (West Germany) The uterine epithelial lining shows a property which is unusual for an epithelium: after proper hormonal conditioning it can enter a special physiological state("receptive state") during which attachment of trophoblast to its apical surf~ce is possible and may be followed (in most species) by invasion. It is hoped that the possibility to manipulate this "receptivity" via its steroid hormone dependency may help to define factors involved in the regulation of invasive processes. We have previously reported on an endometrial organ culture system which apparently allows rabbit endometrium to develop at least many major characteristics of the "receptive state" in vitro (C.T.O.C. Meeting, Milano 1983; Eur.J.Cell Biol. 33, Suppl. 5, 17, 1984). When implantation stage rabbit blastocysts are confronted with these endometrial fragments in vitro, the syncytiotrophoblast can attach to the uterine epithelium and invade it, provided that the culture system allows to maintain a close physical contact for prolonged per iods of time (C.T.O.C. Meeting, Noordwijkerhout 1984). The light and electron microscopical details of attachment and invasion in this system are very similar to what is observed in vivo. Whether or not this "receptivety" involves any specificity for trophoblast is being tested in arecent series of experiments on confrontation of the endometrial fragments .with tumor ce II aggregates. It has previously been reported