CASP9 and cancer: In PEPE2-incubated T24 and J82 cells, the apoptosis-activator Bax level was increased while the anti-apoptotic Bcl-2 amount was decreased and thus, the pro-caspase-9 level dwindled, implying that the mitochondrial pathway was related to cancer cell apoptosis (Figure 3C and Figure S3B).