Table 4.

Antiproliferative activity (GI₅₀) of organochalcogen derivatives in SW1573 and SW1573/P-gp cell lines ¹.

	w/o Verapamil			w Verapamil
	SW1573	SW1573/PGP	Rf	SW153	SW1573/PGP	Rf
15	3.3 ± 0.4	5.0 ± 0.1	1.5	5.0 ± 0.7	5.3 ± 0.3	1.1
16	2.7 ± 0.3	5.1 ± 0.6	1.9	2.3 ± 0.3	5.1 ± 0.4	2.2
35	2.3 ± 0.5	7.1 ± 0.6	3.1	3.1 ± 1.0	7.0 ± 0.6	2.3
36	4.2 ± 0.7	6.8 ± 0.4	1.6	3.1 ± 0.4	5.3 ± 0.6	1.7
38	27 ± 2	29 ± 0.2	1.1	15 ± 3	25 ± 2	1.6
39	3.0 ± 0.5	18 ± 0.1	6.0	2.5 ± 0.1	5.1 ± 0.4	2.0
40	1.9 ± 0.1	3.9 ± 0.2	2.0	1.8 ± 0.2	4.5 ± 1.0	2.5
45	1.1 ± 0.2	3.3 ± 0.6	3.1	1.1 ± 0.1	2.5 ± 0.1	2.3
PTX	1.5 ± 0.5	196 ± 53	128	1.6 ± 0.2	4.2 ± 0.9	2.6
VB	0.9 ± 0.3	2051 ± 682	2388	0.8 ± 0.2	1.0 ± 0.5	1.3

¹ Paclitaxel (PTX) and vinblastine (VB) were used as reference drugs. GI₅₀ values are given in μM for organochalcogen derivatives and in nM for PTX and VB. Standard deviation was calculated from at least two independent experiments. Rf represents the ratio between GI₅₀ values in SW1573/PGP and SW1573 cells.