Epirubicin hydrochloride

) of chemotherapy drugs. NUGC3 cells were grown at 4x10 4 cells/well in a 24-well plate, and transfected with siNegative or siYB-1 after 24 h post seeding using the aforementioned protocol. Then, following transfection for 48 h, treatment with varying concentrations of doxorubicin hydrochloride (0, 0.3125, 0.625, 1.25, 2.5 and 5 µM) or epirubicin hydrochloride (0, 0.3125, 0.625, 1.25, 2.5, 10 and 20 µM) (both from Sigma-Aldrich; Merck KGaA) was performed. The corresponding percentages of cell viability at different concentrations of drugs were determined by MTS assay, after 24 h incubation. Subsequently, 600 µl of MTS mixture (diluted 1:5 in RPMI-1640 with 10% FBS; Promega Corporation, Madison, WI, USA) were added to each of the wells. A negative control set of blank wells containing only MTS solution with no cells was also prepared. Incubation of cells was performed in the dark at 37˚C for 4 h. CellTiter 96 ® AQueous One Solution Cell Proliferation assay reagent (Promega Corporation) was added to cells to measure cell viability. A wavelength of 490 nm was used for measuring of the absorbance with an ELISA plate reader. The IC 50 value of each drug was then determined by plotting the survival rate after 24 h of drug treatment against varying drug concentrations.