Figure 2.

(A) Resistant cells display higher IC⁵⁰ for sorafenib. After treatment with ubenimex, both 786-O-R and ACHN-R displayed low IC⁵⁰ values for sorafenib. (B) Ubenimex dose dependently inhibited p-Akt-ser473 expression. Without treatment, 786-O (C) and 786-O-R (D) cells showed very low levels of apoptosis as assessed by AO/EB staining. (E) Ubenimex enhanced apoptosis in sorafenib resistant cells. (F) Inhibition of autophagy by 3MA resulted in enhanced apoptosis in sorafenib resistant cells, but no more than ubenimex. Data represent three independent experiments. **P < 0.001 versus sorafenib resistant cells; ^##P < 0.001 versus sorafenib resistant cells treated with ubenimex. Bars, 100 μm.