Table 2.

SSJ26 and SSJ32 reverse the P-gp-mediated drug resistance to doxorubicin and paclitaxel.

Treatment	SW620		SW620/Ad300
	IC50 ± SD a (μM)	FR b	IC50 ± SD a (μM)	FR b
Doxorubicin	0.0201 ± 0.0023	(1.00)	4.3221 ± 0.4513	(215.16)
+SSJ26 (1.25 μM)	0.0199 ± 0.0018	(0.99)	0.5314 ± 0.05134	(26.44) *
+SSJ26 (2.5 μM)	0.0185 ± 0.0017	(0.92)	0.3212 ± 0.09021	(15.98) *
+SSJ26 (5 μM)	0.0181 ± 0.0021	(0.90)	0.1017 ± 0.01022	(5.06) **
+SSJ32 (1.25 μM)	0.0210 ± 0.0025	(1.05)	0.6354 ± 0.0724	(31.61) *
+SSJ32 (2.5 μM)	0.0199 ± 0.0021	(0.99)	0.3317 ± 0.0413	(16.50) *
+SSJ32 (5 μM)	0.0189 ± 0.0017	(0.94)	0.1528 ± 0.0132	(7.60) **
+Verapamil (5 μM)	0.0179 ± 0.0015	(0.89)	0.0923 ± 0.0058	(4.59) **
Paclitaxel	0.0072 ± 0.0010	(1.00)	2.7402 ± 0.2813	(380.58)
+SSJ26 (1.25 μM)	0.0063 ± 0.0008	(0.88)	0.2046 ± 0.0194	(28.42) *
+SSJ26 (2.5 μM)	0.0063 ± 0.0009	(0.92)	0.1081 ± 0.0098	(15.01) *
+SSJ26 (5 μM)	0.0057 ± 0.0006	(0.79) *	0.0737 ± 0.0084	(10.23) **
+SSJ32 (1.25 μM)	0.0068 ± 0.0005	(0.94)	0.2977 ± 0.0313	(41.35) *
+SSJ32 (2.5 μM)	0.0064 ± 0.0006	(0.89)	0.1110 ± 0.0092	(15.41) *
+SSJ32 (5 μM)	0.0061 ± 0.0005	(0.85)	0.0872 ± 0.0095	(12.12) **
+Verapamil (5 μM)	0.0062 ± 0.0007	(0.86)	0.0658 ± 0.0068	(9.14) **
Cisplatin	1.8203 ± 0.1744	(1.00)	2.3217 ± 0.3353	(1.28)
+SSJ26 (5 μM)	1.8556 ± 0.2919	(1.02)	2.1842 ± 0.3148	(1.20)
+SSJ32 (5 μM)	1.7453 ± 0.2434	(0.96)	2.1772 ± 0.0210	(1.19)
+Verapamil (5 μM)	1.8012 ± 0.2017	(0.99)	2.0313 ± 0.0251	(1.12)

^a IC₅₀ values are represented as mean ± SD of at least three independent experiments performed in triplicate; ^b Values represent the fold-of-resistance (FR) obtained by dividing IC₅₀ value of antineoplastic drug in SW620 and SW620/Ad300 cells with or without reversal agent divided by the IC₅₀ value of respective antineoplastic drug in SW620 cells without reversal agent. Cell survival assay was determined by the MTT assay as described in Section 2. Verapamil was used as a positive control of P-gp inhibitor; * p < 0.05; ** p < 0.01 versus the control group without reversal agent.