Epidermal growth factor receptor expression in three different human endometrial cancer cell lines

Background. The aim of the current study was to establish the characteristics of the epidermal growth factor (EGF) receptor in endometrial cell lines to determine the possible relation of EGF to endometrial cancer. Methods. Three different cell lines were used: RL95‐2 (derived from a moderately differentiated adenosquamous carcinoma), HEC‐I‐A (from a moderately differentiated adenocarcinoma), and KLE (from a poorly differentiated adenocarcinoma). The binding of (¹²⁵‐I) EGF to these cell lines and the stimulatory effect of EGF on (³H) thymidine incorporation into DNA were examined. Results. EGF receptor was present in all three cell lines. The binding of ¹²⁵‐I‐labeled EGF was saturable and of high affinity. Scatchard analysis of the competitive binding data for KLE, HEC‐I‐A, and RL95‐2 revealed linear plots, indicating a single class of binding sites with almost identical equilibrium dissociation constants (0.34 nM, 0.23 nM, and 0.20 nM, respectively). Other peptides, such as insulin‐like growth factor (IGF) I and II and insulin, did not compete for the receptor. RL95‐2 cells bound significantly more EGF (P < 0.005) than did the HEC‐I‐A and KLE cell lines. EGF increased ³H‐thymidine incorporation in all three cell lines. Conclusion. Because EGF receptors are expressed by all three cell lines at markedly different levels and because EGF stimulates ³H‐thymidine incorporation into DNA in the three cell lines, the current study suggests that EGF may play a role in the promotion of growth endometrial adenocarcinoma.