Figure 2.

PX-12 treatment sensitizes human GBM cells to cytostatic drug treatment. (a) PX-12 causes a concentration-dependent reversal of cisplatin resistance. IC₅₀ concentrations of cisplatin in the absence and presence of 10 µM and 20 µM PX-12 for 72 h, respectively, were obtained from sigmoidal concentration-response curves (0.03–300 µM cisplatin) of MTT assays (n = 3, * p < 0.05); (b) MTT assays with a concentration-response curve of PX-12 in primary human GBM cells treated for 72 h (n = 3); (c) Temozolomide (TMZ) concentration-response curves showing sensitization of primary GBM cells at 100 µM PX-12 incubated for 72 h (upper graph). Respective TMZ IC₅₀ values are depicted in the table below the graph (n = 3, * p < 0.05); (d) Apoptotic rates as determined by annexin-V assays of primary GBM cells treated with either vehicle (DMSO), TMZ (1000 µM), PX-12 (100 µM), or a combination of both for 48 h as indicated. Annexin V positive cells were regarded as apoptotic cells (n = 3, * p < 0.05).