AUTOCRINE MECHANISM OF EPIDERMAL GROWTH-FACTOR IN CHORIOCARCINOMA CELL-PROLIFERATION

We examined four choriocarcinoma cell lines, NaUCC-1, NaUCC-3, NaUCC-4 and BeWo, for the presence of epidermal growth factor (EGF) by enzyme immunoassay and reverse transcription and polymerase chain reaction, and for EGF receptor (EGFR) by I-125-EGF binding assay. Specific EGF b inding and EGF proteins were detected in these four choriocarcinoma ce ll lines. Of the cell lines examined, NaUCC-4 had the greatest EGF bin ding capacity (18 x 10(5) sites/cell) and the highest amount of immuno reactive EGF (142 pg/ml). These results prompted us to assess the sign ificance of EGF/EGFR autocrine mechanism in NaUCC-4 cells. Low doses o f exogenous EGF stimulated H-3-thymidine incorporation, and monoclonal antibodies against EGF or EGFR dose-dependently inhibited 3H-thymidin e incorporation. On the other hand, these antibodies did not significa ntly affect hCG production. These results suggested that EGF might fun ction in an autocrine manner to stimulate proliferation rather than di fferentiation of NaUCC-4 choriocarcinoma cells. Copyright (C) 1996 Els evier Science Ireland Ltd.