Table 2.

Antiproliferative effects of conjugate compounds 27–46 in MCF-7 human breast cancer cells ^a.

Compound	R1	R2	R3	R4	R5	R6	R7	IC50 (μM) b	% Cell Death at 10 μM c
27	H	OH	OMe	H	OMe	OMe	OMe	0.033	10
28	OH	OH	OMe	H	OMe	OMe	OMe	0.005	17
29	H	H	OMe	H	OMe	OMe	OMe	0.087	12
30	OH	H	OMe	H	OMe	OMe	OMe	0.043	19
31	H	OMe	OMe	OMe	H	OMe	H	2.08	1
32	OH	OMe	OMe	OMe	H	OMe	H	0.041	16
33	H	-OCH2O-		H	H	OMe	H	1.47	8
34	OH	-OCH2O-		H	H	OMe	H	0.049	6
35	H	-C4H4-		H	OMe	OMe	OMe	1.51	0
36	OH	-C4H4-		H	OMe	OMe	OMe	3.62	3
37	H	H	Me	H	OMe	OMe	OMe	1.75	2
38	OH	H	Me	H	OMe	OMe	OMe	0.372	12
39	H	H	SMe	H	OMe	OMe	OMe	0.790	3
40	OH	H	SMe	H	OMe	OMe	OMe	0.064	2
41	H	H	Br	H	OMe	OMe	OMe	1.03	5
42	OH	H	Br	H	OMe	OMe	OMe	2.35	7
43	H	F	OMe	H	OMe	OMe	OMe	0.180	2
44	OH	F	OMe	H	OMe	OMe	OMe	0.194	10
45	H	NH2	OMe	H	OMe	OMe	OMe	0.959	8
46	OH	NH2	OMe	H	OMe	OMe	OMe	6.15	6
26 (CA4) d	-	-	-	-	-	-	-	0.008	13
11 e	-	-	-	-	-	-	-	0.029	23
12	-	-	-	-	-	-	-	0.028	11

^a Mean IC₅₀ values of compounds for their antiproliferative effects and percent cytotoxicity on a human MCF-7 breast cancer cell line using the MTT assay. ^b IC₅₀ values are half maximal inhibitory concentrations required to block the growth stimulation of MCF-7 cells. Values are an average of at least three experiments performed in triplicate with typical standard errors below 15%. ^c Lactate Dehydrogenase assay: Following treatment of the cells, the amount of LDH was determined using LDH assay kit from Promega. Data is presented as % cell lysis at compound concentration of 10 µM [66]. ^d The IC₅₀ value obtained for 26 (CA4) in this assay is 8 nM for MCF-7 and is in good agreement with the reported values for CA4 using the MTT assay on human MCF-7 breast cancer cell lines ([59,68,69]). ^e The reported IC₅₀ value for endoxifen 11 in the MCF-7 cell line is 50 nM [70].