Resveratrol induces apoptosis via ROS-triggered autophagy in human colon             cancer cells.
Resveratrol (Res; 3,4',5-trihydroxy-trans-stilbene), which is a polyphenol found in grapes, can block cell proliferation and induce growth arrest and/or cell death in several types of cancer cells. However, the precise mechanisms by which Res exerts anticancer effects remain poorly understood. Res blocked both anchorage-dependent and -independent growth of HT-29 and COLO 201 human colon cancer cells in a dose- and time-dependent manner. Annexin V staining and Western blot analysis revealed that Res induced apoptosis accompanied by an increase in Caspase-8 and Caspase-3 cleavage. In HT-29 cells, Res caused autophagy as characterized by the appearance of autophagic vacuoles by electron microscopy and elevation of microtubule-associated protein 1 light chain 3 (LC3)-II by immunoblotting, which was associated with the punctuate pattern of LC3 detected by fluorescein microscopy. Inhibition of Res-induced autophagy by the autophagy inhibitor 3-methyladenine caused a significant decrease in apoptosis accompanied by decreased cleavage of Casapse-8 and Caspase-3, indicating that Res-induced autophagy was cytotoxic. However, inhibition of Res-induced apoptosis by the pan-caspase inhibitor Z-VAD(OMe)-FMK did not decrease autophagy but elevated LC3-II levels. Interestingly, Res increased the intracellular reactive oxygen species (ROS) level, which correlated to the induction of Casapse-8 and Caspase-3 cleavage and the elevation of LC3-II; treatment with ROS scavenger N-acetyl cysteine diminished this effect. Therefore, the effect of Res on the induction of apoptosis via autophagy is mediated through ROS in human colon cancer cells.
Department of Pathology II, Kansai Medical University, Moriguchi,                     Osaka 570-8506, Japan.
Hisanori
H
Miki
Norihisa
N
Uehara
Ayako
A
Kimura
Tomo
T
Sasaki
Takashi
T
Yuri
Katsuhiko
K
Yoshizawa
Airo
A
Tsubura
D016588:Anticarcinogenic Agents / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D048708:Cell Growth Processes / Q000187:drug effects; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D019073:HT29 Cells; D006801:Humans; D009842:Oligopeptides / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000077185:Resveratrol; D015398:Signal Transduction / Q000187:drug effects; D013267:Stilbenes / Q000494:pharmacology*
D016588:Anticarcinogenic Agents; D000972:Antineoplastic Agents, Phytogenic; D009842:Oligopeptides; D017382:Reactive Oxygen Species; D013267:Stilbenes; C517629:benzyloxycarbonyl-valyl-alanyl-aspartic acid; D053148:Caspase 3; D053181:Caspase 8; D000077185:Resveratrol