Effects of RAL and its analogues on ER-expressing breast cancer cell (MCF-7 and T47D) proliferation. Oestrogen-negative breast cancer cell line (MDA-MB-231) was used as a control. (a, c and e) Agonist effects of raloxifene (RAL) and Y134 on MCF-7, T47D and MDA-MB-231 cell growth relative to vehicle control (100%) in the absence of oestrogen, respectively. (b, d and f) Demonstrate antagonist effects of RAL and the analogue(s) on MCF-7, T47D and MDA-MB-231 cell growth relative to 17β-oestradiol (E2; 1 nM for MCF-7 and 10 nM for T47D and MDA-MB-231 cells; 100%). Values in parentheses indicate respective IC50 (nM) for each compound. Results represent an average of three independent measurements. *P<0.05, **P<0.01 compared to RAL treatment.