Figure 9. Effects of MEK and mTOR inhibitors on the induction of apoptosis induced by doxorubicin. The effects of MEK1 and mTOR inhibitors on doxorubicin IC₅₀ was examined by culturing the indicated cells in the presence of the different concentrations of doxorubicin for three days and then determining the extent of apoptosis induction by annexin V/PI staining. Cells were cultured in medium containing 500 nM 4HT + 100 nM Test and the indicated concentrations of the inhibitors. (A) non-selected FL/ΔAkt-1:ER*(Myr⁺) + ΔRaf-1:AR cells, and (B) doxorubicin-selected FL/ΔAkt-1:ER*(Myr⁺) + ΔRaf-1:AR cells. Symbols: solid squares (■) = doxorubicin, solid downward triangles (▼) = indicated concentrations of doxorubicin and 5,000, 500, 50, 5, 0.5 and 0.05 nM MEK inhibitor, solid diamonds (◆) = indicated concentrations of doxorubicin and 500, 50, 5, 0.5, 0.05 and 0.005 nM mTOR inhibitors, and solid circles (●) = indicated concentrations of doxorubicin and 5,000, 500, 50, 5, 0.5 and 0.05 nM MEK and mTOR inhibitors.