Fig. 4.

Low-dose perifosine enhances the cytotoxicity in ABCB1-overexpressing drug-resistant KBV20C cancer cells. (A) MCF-7/ADR cells were treated with 10 μM perifosine (PERI), 5 μM aripiprazole (ARI), 1.5 μM tariquidar (Tari), or 0.1% DMSO (CON). After 1 h (left panel) or 21 h (right panel), all cells were stained with rhodamine 123 for 3 h and examined by using FACS analysis as described in Materials and Methods. (B) MCF-7/ADR, MCF-7, HaCaT, and MDA-MB-231 cells were treated with 5 nM VIC, 20 μM miltefosine, 10 μM miltefosine, or 0.1% DMSO (CON). After 1 day, all cells were also observed using an inverted microscope at ×100 magnification. (C, D) P-gp overexpressing drug-resistant KBV20C cells were treated with 5 nM VIC, 5 μM perifosine (PERI), 10 μM GSK690693, or 0.1% DMSO (CON). After 1 day, all cells were also observed using an inverted microscope at ×40 magnification. (E) KBV20C cells were treated with 5 nM VIC, 5 μM perifosine (PERI), or 0.1% DMSO (CON). Cell viability assay was performed as described in “Materials and Methods”. The data are presented as the mean ± S.D. of at least two experiments repeated in triplicate experiments. Data are presented as mean ± SD. ****p<0.0001 was considered be statistically significant. (F) KBV20C cells were treated with 5 nM VIC, 5 μM perifosine (PERI), or 0.1% DMSO (CON). After 24 h, western blot analysis was performed using antibodies against C-PARP, α-LC3B, and GAPDH.