Roles of antiestrogen binding sites in human endometrial cancer cells - Hayashida, M.; Terakawa, N.; Shimizu, I.; Ikegami, H.; Wakimoto, H.; Aono, T.; Tanizawa, O.; Matsumoto, K. (Elsevier)
Estrogen-noncompatible antiestrogen binding sites (AEBS) as well as estrogen receptors (ER), and the growth-inhibitory effect of tamoxifen were investigated in two human endometrial cancer cell lines, IK-90 and HEC-IA cells. IK-90 cells contained specific AEBS, but no ER was found in these cells. Scatchard plot analysis of AEBS in 12,000 g supernatant from IK-90 cells showed a high affinity binding site for tamoxifen (K"d:5.6 +/- 1.0nM) with the maximum binding site of 457 +/- 47 fmol/mg protein. However, no measurable ER or AEBS was found in HEC-IA cells. The effect of tamoxifen on the growth of cells was found to be identical in both cell lines; the addition of 10 μ M tamoxifen to culture medium was cytocidal whereas tamoxifen at lower concentrations (1 nM-1μM) did not significantly affect the growth of both IK-90 and HEC-IA cells. These results demonstrate for the first time the presence of AEBS in human endometrial cancer cells. The present results also suggest that AEBS does not play a fundamental role in mediating the growth:inhibitory effect of tamoxifen in endometrial cancer cells.
http://linkinghub.elsevier.com/retrieve/pii/0022-4731(87)91043-0
Keywords: W; V