BML-275, an AMPK inhibitor, induces DNA damage, G2/M arrest and apoptosis in human pancreatic cancer cells

Adenosine monophosphate-activated protein kinase (AMPK) is a principal intracellular energy sensor which regulates energy producing pathways and energy requiring pathways when the cellular AMP/ATP ratio is altered. BML-275 (compound C), a well-known inhibitor of AMPK, has been found to induce apoptosis in myeloma, glioma and prostate cancer cells. However, the mechanisms responsible for the selective apoptotic effect(s) by BML-275 in cancer cells remain unknown. In the present study, BML-275 was investigated for its antitumor effect(s) in human pancreatic cancer cell lines. BML-275 inhibited the cell proliferation of 4 human pancreatic cancer cell lines (MIA PaCa-2, Panc-1, Colo-357 and AsPC-1). In addition, BML-275 significantly increased the generation of intracellular reactive oxygen species (ROS), followed by induction of DNA damage signaling and apoptosis. Furthermore, BML-275 induced cell cycle arrest in the G2/M phase. The inhibition of ROS generation by N-acetyl cysteine (NAC) significantly prevented the induction of DNA damage and apoptosis, but failed to prevent the induction of G2/M arrest by BML-275. Small interfering RNA (siRNA)-mediated knockdown of AMPKα increased the generation of intracellular ROS, DNA damage signaling and apoptosis without cell cycle arrest at the G2/M phase. These findings suggest that BML-275 exerts its antitumor effects by inducing ROS generation, DNA damage and apoptosis via inhibition of the AMPK pathway and by inducing G2/M arrest via a pathway independent of AMPK, implicating its potential application as an antitumor agent for pancreatic cancer.