Table 3. ERα Levels in MCF-7 Cells Determined by the In-Cell Western Immunoassay.

	compound	% ERα remaininga [1 μM]	% efficacyb [1 μM]
thioxo-quinazolinone	15	39.9 ± 8.5	60
	16	40.3 ± 8.6	60
	17	5.5 ± 5.0	95
	18	35.7 ± 11.3	64
5-methoxybenzimidazole	31	113.8 ± 4.3	c
	32	120.3 ± 31.6	c
	34	132.9 ± 14.1	c
	36	130.0 ± 15.1	c
	38	101.8 ± 1.9	c
5-hydroxybenzimidazole	39	99.2 ± 3.5	1
	40	90.0 ± 10.4	10
	41	83.8 ± 29.2	16
	42	92.0 ± 5.5	8
	43	85.2 ± 6.2	15
references	GW7604	44.3 ± 12.1	56
	fulvestrant	0	100
	4-OHT	263.0 ± 9.0	c
	44	165.0 ± 4.0	c

^aERα levels compared to the solvent control (dimethyl sulfoxide (DMSO)). Values represent the mean ± SD of ≥3 independent experiments.

^bEfficacy, calculated as the downregulation of ERα compared to the efficacy of the reference compound fulvestrant.

^cUpregulation.