Figure 2

Sorafenib in combination with vitamin K1 (VK1) induces apoptosis in BT325 (A,C) and U251 (B,D) cells. Cells were treated with sorafenib (2.5 μM), VK1 (50 μM) alone or in combination for 10 h. Then, cells were harvested and stained with annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) followed by flow cytometry analysis. The four different cell populations marked as: unstained cells indicating a live cell population (LL, lower left), annexin V-positive and PI-negative stained cells indicating early apoptosis (LR, lower right), annexin V/PI double-stained cells showing late apoptosis (UR, upper right), and annexin V-negative and PI-positive stained cells showing dead cells (UL, upper left).