Figure 1. Five drugs result in higher sensitization of drug-resistant KBV20C cancer cells treated with eribulin. (A) KBV20C cells were grown on 60 mm-diameter dishes and treated with 10 nM eribulin, 5 nM vinblastine, 5 μM reserpine, 10 nM eribulin with 5 μM reserpine (ERI+RES), 5 nM vinblastine with 5 μM reserpine (VIB+RES), or 0.1% DMSO (control). After 1 day, all cells were observed using an inverted microscope at ×100 magnification. (B-E) Cell viability assay was performed as described in Materials and Methods. The data are presented as the mean±SD of at least two experiments repeated in triplicate. Significantly different at *p<0.05 compared to the corresponding control. (B) KBV20C cells were plated on 96-well plates and grown to 30%-40% confluence. The cells were then stimulated for 48 h with 10 μM of amiodarone (AMI), nicardipine (NIC), propafenone (PRO), carvedilol (CAR), amlodipine (AML), diltiazem (DIL), nifedipine (NIF), nimodipine (NIM), doxazosin mesylate (DOXA), and reserpine (RES) and in combination with 10 nM eribulin or alone, or 0.1% DMSO (control). (C) KBV20C cells were plated on 96-well plates and grown to 30%-40% confluence. The cells were then stimulated for 48 h with 10 μM of triamterene (TRI), isradipine (ISR), midodrine (MID), quinidine (QUI), prazosin (PRA), ethacrynic acid (ETH), losartan potassium (LOS), benazepril (BEN), eplerenone (EPL), and reserpine (RES) and in combination with 10 nM eribulin or alone, or 0.1% DMSO (control). (D) KBV20C cells were plated on 96-well plates and grown to 30%-40% confluence. The cells were then stimulated for 48 h with 10 μM of labetalol (LAB), methyclothiazide (METH), metolazone (METO), valsartan (VAL), and reserpine (RES) and in combination with 10 nM eribulin or alone, or 0.1% DMSO (control). (E) KBV20C cells were plated on 96-well plates and grown to 30%-40% confluence. The cells were then stimulated for 48 h with 10 μM of telmisartan (TEL), spironolactone (SPI) disopyramide (DIS), dipyridamole (DIP), vardenafil (VAR), and reserpine (RES) and in combination with 10 nM eribulin or alone, or 0.1% DMSO (control).