Figure 2.

Siramesine activates caspases in HaCaT and in U-87MG cells. Cells were treated with different siramesine concentrations, and then the total cell lysates were collected at indicated time points. The caspase activities were measured fluorimetrically using Ac-DEVD-AFC (10 μM) based on the initial velocities of substrate hydrolysis. The experiments were performed in triplicate; the bars represent mean±S.D. (a) DEVD-ase activity of HaCaT cells as a function of time and siramesine concentration. (b) DEVD-ase activity of HaCaT and U-87MG cells after 4- and 6-h incubation with siramesine and its prevention by α-tocopherol. (c) DEVD-ase activity of HaCaT and U-87MG cells treated with LLOMe for 18 h. (d) Ultrastructure of siramesine-treated HaCaT and U-87MG cells. Following the treatment, the cells were fixed with 1% glutaraldehyde and embedded in epon. Thin sections were analysed with TEM. Bar size, 5 μm. A, apoptotic cells; S, siramesine; T, α-tocopherol