To investigate if the pathway is involved in PAC-320 induced antitumor activity in prostate cancer cells, we detected the activation of MAP kinases, including extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK) and p38, after PAC-320 treatment (Figure 6A and Supplementary Figure 4). Here, MAPK8 is linked to prostate cancer.