Fig. 2

Proapoptotic effects of Pyr-analogues versus Pyrimethamine and temozolomide on Mel501 and MeWo cell lines. Flow cytometric analysis of apoptosis after the treatment with Pyr (8 μg/ml), TMZ (100 μmol/L) and Pyr-analogues (0.8, 8, 80 μg/ml) for 24, 48 and 72 h on Mel501 (left panels) and MeWo (right panels) cell lines. Columns, mean values of 10 independent experiments; bars, SD. *, P < 0.05; **, P < 0.01, *** P < 0.001 significance compared with untreated cells. All screened compounds, Iso-Pyr (a), MNP (b), MZPES (c) and MBP (d), were able to induce apoptosis but only one of these, MBP (d), was more potent than Pyr and TMZ even at very low concentration (0.8 μg/ml) in both cell lines. Note the significant difference between MBP-treated and TMZ-treated samples after 48 and 72 h even at lower concentration of MBP (0.8 μg/ml)