In vitro cultured human term cytotrophoblast: a model for normal primary epithelial cells demonstrating a spontaneous differentiation programme that requires EGF for extensive development of syncytium

Placenta. 1997 Sep;18(7):577-85. doi: 10.1016/0143-4004(77)90013-3.

Abstract

Normal human term cytotrophoblast cells prepared by trypsin-DNAse I digestion with and without secondary immunological purification with CD9 antibodies were investigated for the expression of morphological and genetic markers of proliferation and differentiation. After 24 h of culture, the cell preparations demonstrated spontaneous formation of microvilli and formation of small syncytial units as assessed by desmoplakin staining and FITC-dextran microinjection. EGF was required for mature syncytial formation. Compared to log-phase proliferating HeLa cells, uptake of [3H]thymidine incorporation was low and quickly decreased to negligible levels. Expression of the proto-oncogenes c-myc, c-fos, and c-jun and histone 2A decreased rapidly in the first 24 h of culture in both cell preparations, followed by an increase in expression of c-fos and junB over the next 3 days of culture. Proto-oncogene changes were similar in attached and suspension cells. Spontaneous increases in alpha hCG, pregnancy-specific beta(1)-glycoprotein and 3 beta-hydroxysteroid dehydrogenase (3 beta OHSD) occurred within 1 day in both cell preparations. EGF receptor blocking antibodies did not inhibit minor degrees of spontaneous syncytial formation nor inhibit spontaneous expression of alpha hCG or 3 beta OHSD mRNA, but did prevent extensive synctialization induced by EGF. The results demonstrate that term cytotrophoblast cells even in serum-free conditions or suspension culture rapidly commit to a non-proliferative differentiation program in culture which includes limited syncytialization and marked hormone mRNA expression. However, EGF is required for extensive syncytial development.

MeSH terms

  • 3-Hydroxysteroid Dehydrogenases / genetics
  • Cell Differentiation*
  • Cell Division
  • Cells, Cultured
  • Epidermal Growth Factor / pharmacology*
  • Epithelial Cells
  • Female
  • Gene Expression
  • Giant Cells / cytology*
  • Humans
  • Microscopy, Electron, Scanning
  • Models, Biological*
  • Pregnancy
  • Proto-Oncogenes / genetics
  • Trophoblasts / cytology*

Substances

  • Epidermal Growth Factor
  • 3-Hydroxysteroid Dehydrogenases