3 4 5 dimethyl 2 thiazolyl 2 5 diphenyl tetrazolium bromide

EVO (98% purity) was purchased by Sigma-Aldrich. DOX (98% purity) was obtained from Meilun Biology Technology Company (Dalian, China). Dulbecco's Modified Eagle Medium (DMEM), fetal bovine serum (FBS), penicillin-streptomycin (PS), phosphate-buffered saline (PBS), propidium iodide (PI) and 0.25% w/v trypsin/1 mM EDTA were purchased from Gibco Life Technologies (Grand Island, USA). The lactate dehydrogenase (LDH) release detection kit was obtained from Roche Diagnostics. Hoechst 33342 and 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl tetrazolium bromide (MTT) were obtained by Molecular Probes (Grand Island, USA). Primary antibodies against cleaved caspase-7, cleaved caspase-9, cleaved PARP, Ras, phosphorylated MEK, MEK, phosphorylated ERK1/2, ERK1/2, XIAP, cIAP1, survivin, P-gp and GAPDH and secondary antibodies were purchased from Cell Signaling Technology.

DOX and dimethyl sulfoxide (DMSO) were obtained from Sigma (St. Louis, MO, USA). DOX was dissolved in DMSO at a concentration of 40 mM, and stored at −20°C. PD was purchased from Chengdu Best Reagent Co., LTD (Chengdu, Sichuan, China), and dissolved in DMSO at a concentration of 40 mM and stored at −20°C. 3-[4,5-Dimethyl-2-thiazolyl]-2,5-diphenyltetrazolium bromide (MTT) and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimi-dazolylcarbocyanine iodide (JC-1) were purchased from Molecular Probes (Eugene, OR, USA). RPMI 1640 medium, fetal bovine serum (FBS) and antibiotics were purchased from Gibco (Carlsbad, CA, USA). Primary antibodies [i.e., poly (ADP-ribose) polymerase (PARP) and β-actin], and secondary antibodies were obtained from Cell Signaling Technology (Beverly, MA, USA).