title: Polysaccharides of Dendrobium officinale inhibit TNF-α-induced apoptosis in A-253 cell line.
abstract: OBJECTIVE
  Our previous study demonstrated that polysaccharides of Dendrobium officinale Kimura et Migo (DP) were capable of enhancing immunomodulation in an experimental model of Sjögren's syndrome, a chronic autoimmune disease mainly affecting the salivary glands. In the present study, we further investigated the protective effect of DP on a human salivary gland cell line A-253 against tumor necrosis factor (TNF)-α-induced apoptosis.
  
  
  METHODS
  TNF-α (100 U/ml) was used as the stimulus for treating the A-253 cells to induce cellular apoptosis. Nuclear factor-kappa B (NF-κB, p65), phosphorylation of mitogen-activated protein kinases (MAPK), reactive oxygen species (ROS) generation, mitochondrial membrane potential and proapoptotic proteins were examined. A-253 cells were pre-treated with DP for 12 h before TNF-α stimulation.
  
  
  RESULTS
  We observed translocation of NF-κB into the nuclei, prolonged MAPK, excessive ROS generation and strongly decreased mitochondrial membrane potential, and subsequently cytochrome C release and caspase-3 activation. However, pre-treatment with DP significantly inhibited the TNF-α-induced apoptotic factors.
  
  
  CONCLUSIONS
  Our data suggested the inhibitory effect of DP on TNF-α-induced apoptosis in a human salivary gland cell line. This inhibition indicated potential inference of DP in the initial plasma membrane-bound complex of TNF-α and its receptors.
authors.affiliation: School of Chinese Medicine, The University of Hong Kong, 1/F, Estate Building, 10 Sassoon Road, Pokfulam, Hong Kong, China.
authors.forename: L
authors.initials: L
authors.lastname: Xiang
authors.forename: C W
authors.initials: CW
authors.lastname: Stephen Sze
authors.forename: T B
authors.initials: TB
authors.lastname: Ng
authors.forename: Y
authors.initials: Y
authors.lastname: Tong
authors.forename: P C
authors.initials: PC
authors.lastname: Shaw
authors.forename: C W
authors.initials: CW
authors.lastname: Sydney Tang
authors.forename: Y B
authors.initials: YB
authors.lastname: Kalin Zhang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D045304:Cytochromes c / Q000378:metabolism; D031667:Dendrobium; D004305:Dose-Response Relationship, Drug; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D010936:Plant Extracts / Q000494:pharmacology*; D011134:Polysaccharides / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012469:Salivary Glands / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D016328:NF-kappa B; D010936:Plant Extracts; D011134:Polysaccharides; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D045304:Cytochromes c; D020929:Mitogen-Activated Protein Kinase Kinases; D053148:Caspase 3