Identification by subtractive hybridization of a spectrum of novel and unexpected genes associated with in vitro differentiation of human cytotrophoblast cells

We have previously demonstrated that epidermal growth factor (EGF), colony stimulating factor-1 (CSF-1), and granulocyte-monocyte colony stimulating factor (GMCSF) stimulate, while transforming growth factor β1 (TGFβ1) inhibits, cytotrophoblast differentiation. To identify genes mediating EGF-induced differentiation, we constructed a subtracted cDNA library between undifferentiated cytotrophoblast and differentiating cytotrophoblast. We identified six novel genes and four known syncytial products α-human chorionic gonadotrophin (αhCG) pregnancy-specific β1-glycoprotein, 3β-hydroxysteroid dehydrogenase, and plasminogen activator inhibitor type 1 whose mRNAs increased during differentiation. Ten other genes were identified whose mRNAs increased during differentiation. Five of these (keratin 19, calcreticulin, heat shock protein 27, serum and glucocorticoid-regulated kinase and adrenomedullin) were not previously reported to be expressed in placenta. Five other genes known to be expressed in placenta were identified: keratin 8, fibronectin, mitochondrial ATP synthase, H19, and cytosolic copper-zinc superoxide dismutase (SOD-1). Several of these genes may have regulatory functions in trophoblast differentiation.