Human (h) placenta-derived choriocarcinoma cell lines (BeWo, JAR, and JEG-3) were examined for expression of pituitary GH (hGH-N) as well as placental GH variant (hGH-V) and chorionic somatomammotropin (hCS, encoded by the hCS-A or hCS-B gene).
Chorionic somatomammotropin (hCS) genes (hCS-A and hCS-B) and the placental growth hormone variant (hGH-V) gene are expressed in the syncytiotrophoblast in vivo, and at low levels in cytotrophoblast-like choriocarcinoma (BeWo) cells.
Induction of CSH1 (chorionic somatomammotropin hormone 1) by NECC1 expression suggested differentiation of choriocarcinoma cells to syncytiotrophoblasts.
Furthermore, overexpression of ovine Pur alpha enhanced transactivation of the oPL gene proximal promoter in both choriocarcinoma cell lines through this novel cis-element.
The tumors of two patients, including one fatal case, contained more human placental lactogen-positive cells than HCG-positive cells, while the tumor of the remaining patient, who had high serum HCG levels, showed a reversed staining pattern resembling that of CC; this patient has been alive without disease for 9 years.