Isochaihulactone induces cell death and initiates Bcl-2 phosphorylation and caspase activation in LNCaP cells. LNCaP cells were treated with 0.2% DMSO (A) or 20 μM isochaihulactone (B) for 48 h and then were fixed and stained for cleaved caspase-3. Nuclei were stained with DAPI. LNCaP cells were treated with 0.2% DMSO (C) or 20 μM isochaihulactone (D) for 60 h and then were fixed and stained with the TUNEL assay. Nuclei were stained with DAPI. (E) Isochaihulactone induced caspase-9 activation, followed by Bcl-2 phosphorylation and then caspase-3 activation. Cells were treated with 20 μM isochaihulactone for the indicated time and analysis by Western blotting. Membranes were probed with caspase-8, phosphor-Asp330 caspase-9, phosphor-Ser70 Bcl-2, cleaved-βaspase-3, PARP antibodies. β-actin was used as an internal control.