Effect of paclitaxel (PTX) and/or MG132 on cell cycle and apoptosis of breast cancer cells and human umbilical vein endothelial cells (HUVECs). (A, B, D, E) PTX or MG132 treatment for 24 h induced G2 arrest and apoptosis in a concentration-dependent manner in MCF-7 and EO771 cells. (C, F) Effect of PTX and/or MG132 treatment for 24 h on cell cycle and apoptosis in HUVECs. MG132 (0.25 μM) had no effect on G2 arrest and apoptosis of HUVECs. When combined with PTX, MG132 had no significant effect compared with the PTX alone group. Data are expressed as means ± standard deviation of 3 independent experiments. P0.1, PTX 0.1 μM; P0.5, PTX 0.5 μM; M0.25, MG132 0.25 μM; M0.5, MG132 0.5 μM; P + M, PTX 0.1 μM and MG132 0.25 μM. * p<0.05 vs. single treatment and control (ctrl) groups. # p<0.05 vs. MG132 and ctrl groups.