title: Apicidin induces endoplasmic reticulum stress- and mitochondrial dysfunction-associated apoptosis via phospholipase Cγ1- and Ca(2+)-dependent pathway in mouse Neuro-2a neuroblastoma cells.
abstract: Apicidin, a fungal metabolite that functions as a histone deacetylase inhibitor, induces apoptosis in cancer cells. We investigated the molecular mechanisms of the anti-cancer effects of apicidin in mouse Neuro-2a neuroblastoma cells. Apicidin induced apoptotic cell death and activation of caspase-12, -9, and -3. Apicidin induced expression of endoplasmic reticulum (ER) stress-associated proteins, including CCAAT/enhancer binding protein homologous protein (CHOP), cleavage of activating transcription factor 6α, and phosphorylation of eukaryotic initiation factor 2α. Inhibition of ER stress by CHOP knockdown or using the ER stress inhibitors, salubrinal and 4-phenylbutyric acid, reduced apicidin-induced cell death. Apicidin induced reactive oxygen species accumulation and mitochondrial membrane potential loss. An antioxidant, N-acetyl cysteine, reduced apicidin-induced cell death, CHOP expression, and mitochondrial dysfunction. In addition, apicidin increased cytosolic Ca(2+), which was blocked by 2-aminoethoxydiphenyl borate, an antagonist of inositol 1,4,5-trisphosphate receptor, and BAPTA-AM, an intracellular Ca(2+) chelator. 2-Aminoethoxydiphenyl borate and BAPTA-AM inhibited apicidin-induced cell death and ER stress. Interestingly, apicidin induced phosphorylation of phospholipase Cγ1 (PLCγ1) and epidermal growth factor receptor (EGFR), and inhibition of PLCγ1 and EGFR reduced cell death and ER stress. Finally, apicidin-induced histone H3 hyperacetylation and reduction of histone deacetylase 2 mRNA expression were not affected by either a PLCγ1 inhibitor, U73122, or the antioxidant, N-acetyl cysteine. Taken together, the results suggest that apicidin induces apoptosis by ER stress and mitochondrial dysfunction via PLCγ1 activation, Ca(2+) release, and reactive oxygen species accumulation in Neuro-2a neuroblastoma cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Medicine, Medical Research Center for Bioreaction to Reactive Oxygen Species, Biomedical Science Institute, Kyung Hee University, Seoul 130-701, Republic of Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Choi
authors.forename: Jung Yeon
authors.initials: JY
authors.lastname: Lee
authors.forename: A-Young
authors.initials: AY
authors.lastname: Choi
authors.forename: Keun-Young
authors.initials: KY
authors.lastname: Hwang
authors.forename: Wonchae
authors.initials: W
authors.lastname: Choe
authors.forename: Kyung-Sik
authors.initials: KS
authors.lastname: Yoon
authors.forename: Joohun
authors.initials: J
authors.lastname: Ha
authors.forename: Eui-Ju
authors.initials: EJ
authors.lastname: Yeo
authors.forename: Insug
authors.initials: I
authors.lastname: Kang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009447:Neuroblastoma / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D010456:Peptides, Cyclic / Q000494:pharmacology*; D051966:Phospholipase C gamma / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D051742:Transcription Factor CHOP / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D010456:Peptides, Cyclic; D017382:Reactive Oxygen Species; C102351:apicidin; D051742:Transcription Factor CHOP; D051966:Phospholipase C gamma; D002118:Calcium