Table 3 Inhibitors used in this study, their functions and concentrations

Bafilomycin A1

Inhibitor of endosomal acidification

100 nmol/L

Brefeldin A

Blocks transport from the endoplasmic reticulum to Golgi complex

25 µg/mL

Monensin

Blocks transport from the Golgi complex to plasma membrane

32.5 µg/mL

Verapamil

P-glycoprotein inhibitor

10 µmol/L

Fumitremorgin C

MDR-associated protein inhibitor

5 µmol/L

MK571

Breast cancer resistance protein inhibitor

50 µmol/L