title: Effects of the epigenetic drug MS-275 on the release and function of exosome-related immune molecules in hepatocellular carcinoma cells.
abstract: BACKGROUND
  Tumor-derived exosomes have been viewed as a source of tumor antigens that can be used to induce anti-tumor immune responses. In the current study, we aim to investigate the regulatory effect of the epigenetic drug MS-275 on hepatoma G2 (HepG2) cell-derived exosomes, especially for their immunostimulatory properties and alteration of some non-specific immune protein expression, such as heat shock protein (HSP) 70, major histocompatibility complex (MHC) class I polypeptide-related sequence A (MICA) and MICB.
  
  
  METHODS
  MS-275 was used to modulate the secretion of exosomes in human HepG2 cells, and exosomes from untreated HepG2 cells served as negative controls. RT-PCR was used to test the expression of HSP70, MICA and MICB in HepG2 cells. Immunogold labeling of exosomes and western blotting analysis were carried out to compare the expression of HSP70, MICA and MICB proteins in exosomes with or without MS-275 treatment. A natural killer (NK) cell cytotoxicity assay and peripheral blood mononuclear cell (PBMC) proliferation assay were used to evaluate the effect of MS-275 on the immunostimulatory ability of exosomes.
  
  
  RESULTS
  Immunogold labeling and western blot analysis showed that modification of MS-275 increased the expression of HSP70 and MICB in exosomes. RT-PCR showed the mRNA levels of HSP70 and MICB were upregulated in HepG2 cells and were consistent with their protein levels in exosomes. The exosomes modified by MS-275 could significantly increase the cytotoxicity of NK cells and proliferation of PBMC (P < 0.05).
  
  
  CONCLUSIONS
  The non-specific immune response of exosomes derived from HepG2 cells could be enhanced with treatment by the histone deacetylase inhibitor (HDACi) drug MS-275; this could provide a potential tumor vaccine strategy against liver cancer.
authors.affiliation: The First Affiliated Hospital, PLA General Hospital, Fucheng Road 51, Beijing, China. wenhuaxiao77@163.com.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Xiao
authors.forename: Weiwei
authors.initials: W
authors.lastname: Dong
authors.forename: Caihong
authors.initials: C
authors.lastname: Zhang
authors.forename: Gaowa
authors.initials: G
authors.lastname: Saren
authors.forename: Paili
authors.initials: P
authors.lastname: Geng
authors.forename: Huixia
authors.initials: H
authors.lastname: Zhao
authors.forename: Quiwen
authors.initials: Q
authors.lastname: Li
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhu
authors.forename: Guanghui
authors.initials: G
authors.lastname: Li
authors.forename: Shufang
authors.initials: S
authors.lastname: Zhang
authors.forename: Ming
authors.initials: M
authors.lastname: Ye
mesh_terms: D001549:Benzamides / Q000494:pharmacology / Q000627:therapeutic use*; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology* / Q000648:ultrastructure; D049109:Cell Proliferation / Q000187:drug effects; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D044127:Epigenesis, Genetic / Q000187:drug effects*; D055354:Exosomes / Q000187:drug effects / Q000276:immunology* / Q000648:ultrastructure; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D056945:Hep G2 Cells; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology* / Q000648:ultrastructure; D011725:Pyridines / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D001549:Benzamides; D018840:HSP70 Heat-Shock Proteins; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A; C098080:MICB antigen; D011725:Pyridines; C118739:entinostat