Enhancement of p53-dependent apoptosis by CHC in an oligomerization-independent manner. (a) Enhanced caspase-3/7 activation during apoptosis induced by monomeric CHC in the presence of p53. H1299 cells were transfected with p53 and CHC expression vectors. At 17 h after transfection, cells were lysed and caspase-3/7 activity in lysates was determined by fluorometric assay. CHC1-494 was used as a negative control for apoptosis assay. (b) Expression levels of p53 and CHC used for (a). (c) Enhanced PARP-1 cleavage caused by p53-mediated apoptosis in response to monomeric CHC expression. The above samples were immunoblotted with anti-PARP-1 antibody and immunocomplex was detected by enhanced chemiluminescence.