Regulation of the synthesis of human chorionic gonadotrophin by 5-bromo-2'-deoxyuridine and dibutyryl cyclic AMP in trophoblastic and nontrophoblastic tumor cells.

Synthesis of hCG and its alpha subunit (hCG-alpha) by trophoblastic tumor cell lines (JEG-3, Reid, and BeWo) and by nontrophoblastic tumor cell lines [ChaGo and three HeLa lines (HeLa CCL2, HeLa S3, and HeLa 65)] was studied. cAMP, dibutyryl cAMP, and 8-bromo-cAMP induced, but 5-bromo-2'-deoxyuridine inhibited, the synthesis of hCG-alpha and hCG in trophoblastic tumor cells, Addition of 5-bromo-2'-deoxyuridine partially blocked the induction by dibutyryl cAMP in these cells. The synthesis of hCG-alpha and hCG in nontrophoblastic tumor cells was stimulated by dibutyryl cAMP. cAMP and 8-bromo-cAMP, however, did not affect the synthesis of hCG-alpha, although the synthesis of hCG was enhanced. 5-Bromo-2'-deoxyuridine induced hCG-alpha synthesis but did not affect hCG synthesis in nontrophoblastic tumor cells. In HeLa S3 and HeLa 65 cells, the amount of hCG-alpha and hCG produced in the presence of dibutyryl cAMP and 5-bromo-2'-deoxyuridine together was greater than the total hormone produced by each inducer separately. Our data indicate that the regulation of the production of hCG-alpha and hCG differs in trophoblastic and nontrophoblastic tumors.