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Sinulariolide Induced Hepatocellular Carcinoma Apoptosis through Activation of Mitochondrial-Related Apoptotic and PERK/eIF2α/ATF4/CHOP Pathway
Department of Physical Medicine and Rehabilitation, Kaohsiung Medical University Hospital, Kaohsiung 80761, Taiwan
National Museum of Marine Biology and Aquarium, Pingtung 94450, Taiwan
Graduate Institute of Animal Vaccine Technology, National Pingtung University of Science and Technology, Pingtung 91202, Taiwan
Department of Ophthalmology, Yuan's General Hospital, Kaohsiung 80249, Taiwan
English Division of the Second Faculty of Medicine, Medical University of Warsaw, Warsaw 02091, Poland
Graduate Institute of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91202, Taiwan
Graduate Institute of Food Science, National Pingtung University of Science and Technology, Pingtung 91202, Taiwan
Department of Beauty Science, Meiho University, Pingtung 91202, Taiwan
Department of Hospitality Management, Meiho University, Pingtung 91202, Taiwan
These authors contributed equally to this work.
* Author to whom correspondence should be addressed.
Received: 22 July 2013; in revised form: 14 August 2013 / Accepted: 19 August 2013 / Published: 22 August 2013
Abstract: Sinulariolide, an active compound isolated from the cultured soft coral Sinularia flexibilis, has potent anti-microbial and anti-tumorigenesis effects towards melanoma and bladder cancer cells. In this study, we investigated the effects of sinulariolide on hepatocellular carcinoma (HCC) cell growth and protein expression. Sinulariolide suppressed the proliferation and colony formation of HCC HA22T cells in a dose-dependent manner and induced both early and late apoptosis according to flow cytometry, Annexin V/PI stain and TUNEL/DAPI stain analyses. A mechanistic analysis demonstrated that sinulariolide-induced apoptosis was activated through a mitochondria-related pathway, showing up-regulation of Bax, Bad and AIF, and down- regulation of Bcl-2, Bcl-xL, MCl-1 and p-Bad. Sinulariolide treatment led to loss of the mitochondrial membrane potential, release of mitochondrial cytochrome c to the cytosol, and activation of both caspase-9 and caspase-3. Sinulariolide-induced apoptosis was significantly blocked by the caspase inhibitors Z-VAD-FMK and Z-DEVD-FMK. The increased expression of cleaved PARP also suggested that caspase-independent apoptotic pathway was involved. In the western blotting; the elevation of ER chaperones GRP78; GRP94; and CALR; as well as up-regulations of PERK/eIF2α/ATF4/CHOP; and diminished cell death with pre-treatment of eIF2α phosphatase inhibitor; salubrinal; implicated the involvement of ER stress-mediated PERK/eIF2α/ATF4/CHOP apoptotic pathway following sinulariolide treatment in hepatoma cells. The current study suggested sinulariolide-induced hepatoma cell cytotoxicity involved multiple apoptotic signal pathways. This may implicate that sinulariolide is a potential compound for the treatment of hepatocellular carcinoma.
Keywords: hepatocellular carcinoma; sinulariolide; mitochondrial; PERK/eIF2α/ATF4/CHOP; apoptosis
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Chen, Y.-J.; Su, J.-H.; Tsao, C.-Y.; Hung, C.-T.; Chao, H.-H.; Lin, J.-J.; Liao, M.-H.; Yang, Z.-Y.; Huang, H.H.; Tsai, F.-J.; Weng, S.-H.; Wu, Y.-J. Sinulariolide Induced Hepatocellular Carcinoma Apoptosis through Activation of Mitochondrial-Related Apoptotic and PERK/eIF2α/ATF4/CHOP Pathway. Molecules 2013, 18, 10146-10161.
Chen Y-J, Su J-H, Tsao C-Y, Hung C-T, Chao H-H, Lin J-J, Liao M-H, Yang Z-Y, Huang HH, Tsai F-J, Weng S-H, Wu Y-J. Sinulariolide Induced Hepatocellular Carcinoma Apoptosis through Activation of Mitochondrial-Related Apoptotic and PERK/eIF2α/ATF4/CHOP Pathway. Molecules. 2013; 18(9):10146-10161.
Chen, Yi-Jen; Su, Jui-Hsin; Tsao, Chia-Yu; Hung, Chun-Tzu; Chao, Hsiang-Hao; Lin, Jen-Jie; Liao, Ming-Hui; Yang, Zih-Yan; Huang, Han H.; Tsai, Feng-Jen; Weng, Shun-Hsiang; Wu, Yu-Jen. 2013. "Sinulariolide Induced Hepatocellular Carcinoma Apoptosis through Activation of Mitochondrial-Related Apoptotic and PERK/eIF2α/ATF4/CHOP Pathway." Molecules 18, no. 9: 10146-10161.