Figure 1.

VOR enhances DOX-induced cytotoxicity in several cancer cell lines. (a) Isobologram analysis was performed to assess the synergistic cytotoxic effects between VOR and DOX. Three cervical cancer cell lines, HeLa, CaSki and SiHa, as well as the osteosarcoma cell line U2OS, were co-treated for 24 h at various combinations of concentrations. Notably, all four cancer cell lines showed synergistic cytotoxic effects, as the data sets (•) are located below the control line (a straight line). The data points in the isobologram are the mean values of four independent replicates. V=VOR, D=DOX. (b) HeLa or CaSki cells were treated with vehicle, 2.5 μM VOR, and/or 0.2 μM DOX for 24 h, and FACS analysis was performed with 0.5 μg ml⁻¹ Annexin V-FITC to assess the apoptotic cell population. Compared with the single treatments, VOR and DOX co-treatments notably increased the Annexin V-FITC-positive cell populations. Veh=vehicle, V=VOR, D=DOX.