Table 1.

Inhibition of Tubulin Polymerization, Binding of Colchicine to Tubulin, and Growth of MCF-7 Human Breast Carcinoma Cells by Compounds 6–45 and References 1–5

compd	R	X	tubulin assembly IC50 ± SDa (μM)	MCF-7 IC50 ± SDb,c (nM)	colchicine binding inhibitionc,d (% ± SD)
6	4-Br	S	2.4 ± 0.1	400 ± 70	33 ± 2
7	4-Br	C=O	>20 (partial activity)e	430 ± 100	ndf
8	4-Cl	S	1.6 ± 0.07	290 ± 50	48 ± 5
9	4-Cl	C=O	3.6 ± 0.2	260 ± 50	38 ± 3
10	4-Cl	CH2	17 ± 0.2	>5000	nd
11	4-F	S	1.7 ± 0.07	80 ± 30	80 ± 0.4
12	4-F	C=O	1.6 ± 0.08	65 ± 7	63 ± 1
13	4-MeO	S	>20 (partial activity)e	1400 ± 300	nd
14	4-MeO	C=O	>20 (no activity)g	>5000	nd
15	5-Br	S	1.3 ± 0.1	320 ± 100	39 ± 3
16	5-Br	C=O	>40	530 ± 100	nd
17	5-Br	CH2	4.0 ± 0.5	700 ± 300	31 ± 2
18	5-Cl	S	1.5 ± 0.2	280 ± 70	49 ± 5
19	5-Cl	C=O	>20	330 ± 100	nd
20	5-Cl	CH2	4.4 ± 0.8	310 ± 10	38 ± 3
21	5-F	S	1.5 ± 0.1	300 ± 0	61 ± 4
22	5-F	C=O	13 ± 0.4	240 ± 90	nd
23	5-OMe	S	2.1 ± 0.01	200 ± 80	58 ± 0.5
24	5-OMe	C=O	8.3 ± 1	170 ± 60	nd
25	5-OMe	CH2	3.5 ± 0.4	100 ± 0	41 ± 0.9
26	6-Br	S	1.9 ± 0.2	9.0 ± 2	87 ± 0.6
27	6-Br	C=O	1.3 ± 0.2	30 ± 2	86 ± 0.4
28	6-Cl	S	1.2 ± 0.2	20 ± 10	88 ± 3
29	6-Cl	C=O	1.4 ± 0.06	35 ± 7	71 ± 5
30	6-Cl	CH2	1.6 ± 0.01	55 ± 20	72 ± 6
31	6-F	S	2.4 ± 0.2	80 ± 20	74 ± 2
32	6-F	C=O	10 ± 0.4	600 ± 0	nd
33	6-MeO	S	1.1 ± 0.1	1.3 ± 0.6	96 ± 1
34	6-MeO	C=O	1.2 ± 0.06	30 ± 10	95 ± 0.4
35	7-Br	S	1.6 ± 0.2	25 ± 5	82 ± 1
36	7-Br	C=O	1.7 ± 0.1	4.0 ± 0.5	72 ± 0.3
37	7-Cl	S	1.3 ± 0.2	50 ± 10	82 ± 0.3
38	7-Cl	C=O	1.8 ± 0.05	9.0 ± 1	69 ± 0.5
39	7-Cl	CH2	2.4 ± 0.2	200 ± 0	50 ± 4
40	7-F	S	1.0 ± 0.1	20 ± 9	92 ± 0.3
41	7-F	C=O	1.7 ± 0.1	30 ± 0	67 ± 3
42	7-OMe	S	1.2 ± 0.01	19 ± 10	87 ± 2
43	7-OMe	C=O	1.8 ± 0.1	200 ± 0	62 ± 3
44	6,7-Cl2	S	1.2 ± 0.1	7.0 ± 3	92 ± 2
45	6,7-Cl2	C=O	1.5 ± 0.03	15 ± 5	93 ± 0.7
1			3.2 ± 0.4	5.0 ± 1	nd
2			1.0 ± 0.1	13 ± 3	98 ± 0.6
3h			3.3 ± 0.1	52 ± 7	nd
4i			2.0 ± 0.2	13 ± 3	93 ± 0.8
5i			2.5 ± 0.3	42 ± 10	76 ± 0.2

^aInhibition of tubulin polymerization. Tubulin was at 10 μM in the assembly assay.

^bInhibition of growth of MCF-7 human breast carcinoma cells.

^cCompounds that inhibited tubulin assembly with IC₅₀ ≤ 5 μM were tested in the cellular and colchicine binding assays.

^dInhibition of [³H]colchicine binding. Tubulin was at 1 μM. Both [³H]colchicine and inhibitor were at 5 μM.

^ePartial inhibition at 20 μM.

^fNo data.

^gLittle or no activity at 20 μM.

^hReference 15.

ⁱReference 16.