Compound 5 causes caspase activation. A) qRT-PCR analysis of caspase 3, 4, 8 and 9 mRNA in compound 5-treated cells (GI50) as compared to vehicle-treated control cells [set as 1 arbitrary unit (a.u.)]. Values were normalized to β-actin. Scale bars: mean ± SEM of three independent experiments performed in triplicates. *p < 0.05, **p < 0.01 compared to vehicle-treated control cells, B) Representative Western blots showing cleavage “activation’ of procaspase 3 to the active form p17, procaspase 4 to the active form p20, and procaspase 9 to the active forms p35/p37. C: vehicle-treated control cells; 0.5%: 0.5% DMSO-treated cells; 1%: 1% DMSO-treated cells; 5%: 5% DMSO-treated cells; C.5: Compound 5-treated cells. The experiment was repeated three times.