We previously reported the anticancer effects of
MHY218, which is a
hydroxamic acid derivative, in HCT116 human
colon cancer cells. In the present study, the involvement of autophagy in the MHY218-induced apoptotic cell death of AGS human
gastric cancer cells was investigated.
MHY218 treatment induced growth inhibition and apoptotic cell death in a concentration- and time-dependent manner. The induction of apoptosis was confirmed by observations of decreased viability, DNA fragmentation, and an increase in late apoptosis and sub-G1
DNA, which were detected with a flow cytometric analysis. Western blot analyses showed that
MHY218 treatment resulted in decreased
protein levels of
procaspase-8, -9, and -3; cleavage of
poly(ADP-ribose) polymerase (PARP); and alterations in the ratio of Bax/Bcl-2
protein expression. Apoptosis induced by
MHY218 was involved in the activation of
caspase-8, -9, and -3, and it was blocked by the addition of Z-VAD‑FMK, a pan-
caspase inhibitor. In addition, autophagy-inducing effects of
MHY218 were indicated by cytoplasmic vacuolation, the accumulation of acidic vesicular organelles, the appearance of
green fluorescent protein-light-chain 3 (LC3) punctate dots, and increased levels of
Beclin-1 and LC3-II
protein expression. Pretreatment with the autophagy inhibitors
LY294002,
3-methyladenine,
chloroquine, and
bafilomycin A1 enhanced the induction of apoptosis by
MHY218, and this was accompanied by an increase in PARP cleavage. Taken together, these results provide new insights into the role of
MHY218 as a potential
antitumor agent. The combination of
MHY218 with an autophagy inhibitor might be a useful candidate for the
chemoprevention and/or treatment of
gastric cancer.