Figure 1

Cytotoxicity of proteasome inhibitors alone or in combination with nelfinavir in NSCLC cell lines. Cell viability assays (MTS) were performed with NSCLC cell lines A549 (adenocarcinoma), H460 (large cell lung cancer), H157 (squamous cell carcinoma) and H1703 (adenocarcinoma), and dose‒response curves were obtained to calculate the IC50 values for the drugs in all cell lines (presented in Table S1). Cells were treated with increasing concentrations of (A) bortezomib and (B) carfilzomib for two hours, washed, and then left in drug-free medium for an additional 48 h. (C) Cells were treated with increasing concentrations of nelfinavir continuously for 48 h. Data represent the mean ± SD of at least three replicates. Escalating doses of (D) bortezomib and (E) carfilzomib were added for 2 h. After washing away proteasome inhibitors, nelfinavir was added for an additional 48 h at a concentration of 10 µM, except for A549 cells, where a concentration of 20 µM was used. The synergistic effect for drug combinations was calculated, and the most significant synergy is presented in Table S2. Data represent the mean ± SD of at least three replicates.