Table 4.
Comparative analysis of the cytotoxic potential of mandelalide A or erlotinib to a panel of human glioblastoma cells.
| Relative IC50 (nM) ± SEM | ||||
|---|---|---|---|---|
| Cell Line | Mandelalide A 3 Day | Mandelalide A 6 Day | Erlotinib 3 Day | Erlotinib 6 Day |
| U87-MG | 0.38 ± 0.01 | 0.85 ± 0.11 | >300 | ~100 1 |
| U251 | 1.72 ± 0.22 | 1.21 ± 0.26 | >300 | >300 |
| SF-295 | >10 1 | 1.26 ± 0.23 | >300 | >300 |
| SF-268 | >300 | 1.07 ± 0.26 | >300 | >300 |
| U118-MG | >300 | 1.21 ± 0.19 | >300 | >300 |
1 Limited cytotoxic efficacy; absolute IC50 not determined (>300 nM or not active). Human glioblastoma cells were exposed to increasing concentrations of mandelalide A, erlotinib, or vehicle (0.1% DMSO), and the metabolic activity of the cultures was assessed at three days or six (three + three) days using a CellTiter-Glo® assay. Relative IC50 values were determined by nonlinear regression analysis fit of the data to a logistic equation, with the viability of vehicle-treated control cells used to define 100% viability. A single concentration of salinosporamide A (1 µM) was used as a positive cytotoxic control. Values represent the average of three independent experiments.