Inhibitory Role Of Amp-Activated Protein Kinase In Necroptosis Of Hct116 Colon Cancer Cells With P53 Null Mutation Under Nutrient Starvation

Simultaneous induction of other types of programmed cell death, alongside apoptosis, in cancer cells may be considered an attractive strategy for the development of more effective anticancer therapies. The present study aimed to investigate the role of AMP-activated protein kinase (AMPK) in nutrient/serum starvation-induced necroptosis, which is a programmed form of necrosis, in the presence or absence of p53. The present study detected higher cell proliferation and lower cell death rates in the HCT116 human colon cancer cell line containing a p53 null mutation (HCT116 p53(-/-)) compared with in HCT116 cells harboring wild-type p53 (HCT116 p53(+/+)), as determined using a cell viability assay. Notably, western blot analysis revealed a relatively lower level of necroptosis in HCT116 p53(-/-) cells compared with in HCT116 p53(+/+) cells. Investigating the mechanism, it was revealed that necroptosis may be induced in HCT116 p53(+/+) cells by significantly increasing reactive oxygen species (ROS) and decreasing mitochondrial membrane potential (MMP), whereas little alterations were detected in HCT116 p53(-/-) cells. Unexpectedly, a much lower level of ATP was detected in HCT116 p53(-/-) cells compared with in HCT116 p53(+/+) cells. Accordingly, AMPK phosphorylation on the Thr172 residue was markedly increased in HCT116 p53(-/-) cells. Furthermore, western blot analysis and ROS measurements indicated that AMPK inhibition, using dorsomorphin dihydrochloride, accelerated necroptosis by increasing ROS generation in HCT116 p53(-/-) cells. However, AMPK activation by AICAR did not suppress necroptosis in HCT116 p53(+/+) cells. In conclusion, these data strongly suggested that AMPK activation may be enhanced in HCT116 p53(-/-) cells under serum-depleted conditions via a drop in cellular ATP levels. In addition, activated AMPK may be at least partially responsible for the inhibition of necroptosis in HCT116 p53(-/-) cells, but not in HCT116 p53(+/+)cells.