Presence of epidermal growth factor (EGF) receptor and proliferative response to EGF in six human ovarian carcinoma cell lines

We investigated the role of the EGF-EGFR system as a regulator of ovarian cancer cell growth. In five (OVCA 433, OV 166, OV 1225, OV RS 1000, JA1) of six ovarian cancer cell lines examined we showed the presence of a single high-affinity 125I-EGF binding site with Kd varying from 0.24 to 0.86 nM and a number of binding sites/cell from 9700 to 75 000. In OVCA 433, OV 166, and OV RS 1000 cells we demonstrated a low-affinity 125I-EGF binding site with Kd ranging from 1.10 to 2.12 nM. TR-170 cells lacked the EGF binding and were unresponsive to EGF in terms of cell proliferation while all EGFR+ cells except JA 1 exhibited a proliferative response to EGF. Moreover, the growth response of the four EGF-sensitive cell lines showed different patterns since at high EGF concentrations (100 ng ml−1) there was no longer a stimulatory effect in OV 1225, OV 166, and OV RS 1000 cells while the mitogenic activity was still present in OVCA 433 cells. Our results demonstrate that EGF plays a role in regulating ovarian cancer cell growth. However, the presence of EGFR is not a perfect indicator of the EGFR system functionality. The cell lines we have examined could be useful models to clarify the mechanism of EGF action and the role played by the EGF system in the onset and spread of ovarian tumors.