Table 1. IC₅₀ (μM) of different chemotherapeutic drugs in A549 and A549/MDR cells.

		A549	A549	A549	A549/MDR	A549/MDR	A549/MDR
Drug	Transporter	CTRL	ZA	NZ	CTRL	ZA	NZ
doxorubicin	Pgp, MRP1, MRP2, MRP3, BCRP	0.53 ± 0.06	0.41 ± 0.07	0.36 ± 0.07 *	1.83 ± 0.14°	1.53 ± 0.12	1.01 ± 0.18 *
vinblastine	Pgp, MRP1, MRP2	2.34 ± 0.25	1.24 ± 0.12 *	0.78 ± 0.13 *	12.37 ± 0.21°	5.41 ± 0.64 *	1.86 ± 0.44 *
etoposide	Pgp, MRP1, MRP2, MRP3	3.25 ± 0.12	0.87 ± 0.14 *	0.51 ± 0.12 *	8.33 ± 0.44°	5.43 ± 0.27 *	0.91 ± 0.12 *
irinotecan	Pgp, MRP1, MRP2	4.21 ± 0.15	3.37 ± 0.12	2.11 ± 0.12 *	8.11 ± 0.42°	6.77 ± 0.43	3.33 ± 0.41 *
cisplatin	MRP1, MRP2, MRP4	8.11 ± 0.44	1.37 ± 0.09 *	0.81 ± 0.11 *	12.88 ± 0.21°	1.97 ± 0.27 *	0.65 ± 0.12 *
oxaliplatin	MRP1, MRP4	2.87 ± 0.14	1.34 ± 0.17 *	1.03 ± 0.12 *	5.20 ± 0.32°	3.21 ± 0.17 *	1.86 ± 0.31 *
5-fluorouracile	MRP1, MRP3, MRP4, MRP5	4.42 ± 0.18	4.11 ± 0.17	4.26 ± 0.09	7.01 ± 0.45°	5.88 ± 0.36	5.15 ± 0.12
methotrexate	MRP4, Pgp, MRP1, MRP2, MRP3, BCRP	3.27 ± 0.11	1.88 ± 0.28 *	0.61 ± 0.14 *	9.37 ± 0.63°	8.67 ± 1.09	4.32 ± 0.67 *
pemetrexed	MRP5	0.51 ± 0.11	0.25 ± 0.08 *	0.07 ± 0.02 *	11.21 ± 0.87°	8.76 ± 0.77	2.51 ± 0.47 *
gemcitabine	MRP5	0.07 ± 0.02	0.04 ± 0.01 *	0.03 ± 0.01 *	0.88 ± 0.15°	0.81 ± 0.13	0.12 ± 0.04 *
mitoxantrone	BCRP, Pgp, MRP1	10.22 ± 0.88	5.24 ± 0.67 *	1.17 ± 0.18 *	17.88 ± 0.67°	12.33 ± 0.73	2.67 ± 0.25 *

Untreated (CTRL) A549 and A549/MDR cells, cells treated with 1 μM ZA or NZ, were incubated for 72 h with increasing concentrations of chemotherapeutic drugs, then stained in quadruplicate with neutral red (n = 3). Versus respective CTRL: *p < 0.02; A549/MDR versus A549 cells: °p < 0.005.