Archives of Biochemistry and Biophysics 2015-01-15

Tumor necrosis factor-α-induced apoptosis of gastric cancer MKN28 cells: accelerated degradation of the inhibitor of apoptosis family members.

Maki Kitagawa, Atsushi Shiozaki, Daisuke Ichikawa, Shingo Nakashima, Toshiyuki Kosuga, Hirotaka Konishi, Shuhei Komatsu, Hitoshi Fujiwara, Kazuma Okamoto, Eigo Otsuji

文献索引：Arch. Biochem. Biophys. 566 , 43-8, (2015)

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摘要

The role of the inhibitor of apoptosis (IAP) family members in tumor necrosis factor-α (TNF-α)-induced apoptosis of human gastric cancer MKN28 cells was explored. TNF-α induced up-regulation of cIAP2, whereas cycloheximide (CHX) induced down-regulation of XIAP and survivin. Degradation of cIAP1 and XIAP, but not survivin, was accelerated by co-treatment of cells with TNF-α and CHX, and TNF-α-induced up-regulation of cIAP2 was inhibited by BMS-345541 (NF-κB inhibitor). Treatment of MKN28 cells with TNF-α plus CHX induced degradation of survivin and activation of caspase-8 and -3, followed by degradation of cIAP1 and XIAP and apoptosis. Proteasome inhibitors (MG132 and epoxomicin) suppressed TNF-α plus CHX-induced degradation of survivin, cIAP1, and XIAP as well as apoptosis. A caspase inhibitor (z-VAD-fmk) suppressed TNF-α plus CHX-induced apoptosis, but allowed degradation of survivin, cIAP1 and XIAP. TNF-α receptor 1 and 2 were expressed on MKN28 cells. The magnitude of apoptosis induced by TNF-α plus BMS-345541 was much less than that induced by TNF-α plus CHX. These findings suggest that TNF-α plus CHX-induced apoptosis of gastric cancer MKN28 cells may be caused by accelerated degradation of the IAP family members (survivin, cIAP1, and XIAP), in addition to inhibition of NF-κB-dependent synthesis of anti-apoptotic molecules. Copyright © 2014 Elsevier Inc. All rights reserved.