Epidermal growth factor receptors in cultured human trophoblast cells from first- and third-trimester placentas.
Epidermal growth factor (EGF) receptors were studied during the in vitro differentiation of human trophoblast cells from first- and third-trimester placentas. Cytotrophoblasts were isolated by enzymatic digestion and purified on a discontinuous Percoll gradient. As analyzed by flow cytometry, 5% of the cells are in the G2M phase in the early placenta and 0% in the term placenta. In culture, the cytotrophoblasts at both gestational ages flatten out, aggregate, and fuse together to form syncytiotrophoblasts. This in vitro morphological differentiation is associated with a threefold increase in the ability to bind specifically 125I-EGF. Trophoblastic cells from the term placenta have a significantly (p less than 0.005) higher receptor number (68.6 +/- 9.5 fmol/mg protein) for EGF after 2 days of culture than first-trimester cytotrophoblasts (35.8 +/- 2.3 fmol/mg protein). Scatchard plot analysis revealed two classes of binding sites with a similar affinity in both first-trimester and term placentas (9.5 x 10(9) M-1 for the high-affinity, 0.5 x 10(9) M-1 for the low affinity site). When 125I-EGF was affinity cross-linked to cytotrophoblasts, the receptors appeared as a specific band with a molecular weight of 180 kD in SDS-PAGE. This study demonstrates that the culture of cytotrophoblasts offer an appropriate model to study the modulation of EGF receptors.
Mirlesse
V
V
Laboratoire de Physiopathologie du Développement, CNRS-URA 1337, Paris, France.
Alsat
E
E
Fondacci
C
C
Evain-Brion
D
D
D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D003432:Cross-Linking Reagents; D004815:Epidermal Growth Factor; D066246:ErbB Receptors / Q000032:analysis*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007457:Iodine Radioisotopes; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011263:Pregnancy Trimester, Third; D014327:Trophoblasts / Q000378:metabolism*
D003432:Cross-Linking Reagents; D007457:Iodine Radioisotopes; D004815:Epidermal Growth Factor; D066246:ErbB Receptors