PRIMA­1met induces autophagy in colorectal cancer cells through upregulation of the mTOR/AMPK­ULK1­Vps34 signaling cascade.

ABSTRACT

p53­reactivation and induction of massive apoptosis­1, APR­017 methylated (PRIMA­1met; APR246) targets mutant p53 to restore its wild­type structure and function. It was previously demonstrated that PRIMA­1met effectively inhibited the growth of colorectal cancer (CRC) cells in a p53­independent manner, and distinctly induced apoptosis by upregulating Noxa in p53­mutant cell lines. The present study including experiments of western blotting, acridine orange staining and transmission electron microscopy revealed that PRIMA­1met induced autophagy in CRC cells independently of p53 status. Importantly, PRIMA­1met not only promoted autophagic vesicle (AV) formation and AV­lysosome fusion, but also increased lysosomal degradation. Furthermore, Cell Counting Kit­8 assay, colony formation assay and small interfering RNA transfection were performed to investigate the underling mechanisms. The study indicated that activation of the mTOR/AMPK­ULK1­Vps34 autophagic signaling cascade was key for PRIMA­1met­induced autophagy. Additionally, autophagy served a crucial role in the inhibitory effect of PRIMA­1met in cells harboring wild­type p53, which was closely associated with the increased expression of Noxa. Taken together, the results determined the effect of PRIMA­1met on autophagy, and further revealed mechanistic insights into different CRC cell lines. It was concluded that PRIMA­1met­based therapy may be an effective strategy for CRC treatment.