JNK signaling pathway is involved in piperlongumine-mediated apoptosis in human colorectal cancer HCT116 cells

Piperlongumine (PPLGM), an alkaloid isolated from the long pepper (Piper longum L.), can selectively trigger cancer cell death in colorectal cancer cells. The present study investigated whether the c-Jun NH2-terminal kinase (JNK) signaling pathway is involved in PPLGM-induced apoptosis in the human colorectal cancer HCT116 cell line. The results demonstrated that PPLGM reduced the cell viability and induced cell apoptosis in a time- and concentration-dependent manner, without a significant effect on cell cycle distribution. Meanwhile, treatment with 10 mu M PPLGM resulted in JNK activation within 1 h, and a marked and sustained increase in c-Jun phosphorylation in the HCT116 cells. In addition, SP600125, a general inhibitor of JNK, inhibited PPIGM-induced apoptosis in the HCTH6 cells by inhibiting PPI,GM-induced c-Jun phosphorylation. Altogether, it can be concluded that the.INK signaling pathway, at least in part, is involved in PPLGM-mediated apoptosis in HCI116 cells.