title: ONTD induces apoptosis of human hepatoma Bel-7402 cells via a MAPK-dependent mitochondrial pathway and the depletion of intracellular glutathione.
abstract: 3-Oxo-29-noroleana-1,9(11),12-trien-2,20-dicarbonitrile (ONTD) is a novel synthetic derivative of glycyrrhetinic acid (GA), which has the ability to inhibit the proliferation of human hepatocellular carcinoma (HCC) cells. However, the mechanisms by which ONTD exerts its inhibitory effects remain elusive. The present study was conducted to investigate the cytotoxicity of ONTD in Bel-7402 cells and its molecular mechanisms. We found that ONTD depleted intracellular GSH, increased the level of ROS, and consequently induced mitochondrial permeability transition (MPT) leading to the release of apoptosis-inducing factor (AIF) and cytochrome c (Cyt c) to the cytosol. Mitochondrial alteration and subsequent apoptotic cell death in ONTD-treated Bel-7402 cells could be blocked by addition of exogenous antioxidants N-acetylcystein (NAC), GSH and the MTP inhibitor cyclosporin A (CsA). In addition, ONTD activated the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (MAPK) but not extracellular signal-regulated protein kinases (ERK 1/2). When the cells were exposed to SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor), the deregulation of the expression of apoptotic proteins was attenuated. Furthermore, 40 mg/kg ONTD significantly reduced tumor weight (-70.62%, p<0.01) in the H22 tumor-bearing mouse model in vivo. Taken together, these findings provide the first experimental evidence supporting that ONTD could induce apoptosis of Bel-7402 cells via MAPK-mediated mitochondrial pathway and ONTD has the potential to be developed as a therapeutic agent for the treatment of HCC.
authors.affiliation: State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, PR China; Department of Pharmacology, China Pharmaceutical University, Nanjing 210009, PR China.
authors.forename: Jiani
authors.initials: J
authors.lastname: Tan
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Lai
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.forename: Wenyan
authors.initials: W
authors.lastname: Long
authors.forename: Tong
authors.initials: T
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Zha
authors.forename: Linna
authors.initials: L
authors.lastname: Wang
authors.forename: Meiyu
authors.initials: M
authors.lastname: Chen
authors.forename: Hui
authors.initials: H
authors.lastname: Ji
authors.forename: Yisheng
authors.initials: Y
authors.lastname: Lai
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000201:enzymology* / Q000473:pathology; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008113:Liver Neoplasms / Q000201:enzymology* / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D017382:Reactive Oxygen Species / Q000378:metabolism; D014315:Triterpenes / Q000737:chemistry / Q000494:pharmacology*
chemical_list: C581004:3-oxo-29-noroleana-1,9(11),12-trien-2,20-dicarbonitrile; D000975:Antioxidants; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D017382:Reactive Oxygen Species; D014315:Triterpenes; D005978:Glutathione
keywords: Apoptosis; GSH; Hepatocellular carcinoma; MAPKs; Mitochondria