title: Korean mistletoe lectin regulates self-renewal of placenta-derived mesenchymal stem cells via autophagic mechanisms.
abstract: OBJECTIVE
  The balance between survival and death is a key point for regulation of physiology of stem cells. Recently, applications of natural products to enhance efficiencies in culturing and differentiation of stem cells are increasing. Korean mistletoe lectin (Viscum album L. var. coloratum agglutinin, VCA) has been known to be toxic to some cancer cells, but it is still unclear whether VCA has a cytotoxic or indeed a proliferative effect on mesenchymal stem cells (MSCs). Here, we have compared effects of VCA in naïve placenta-derived stem cells (PDSCs), immortalized PDSCs and cancer cells (HepG2), and analysed their mechanisms.
  
  
  METHODS
  MTT assay was performed to analyse effects of VCA on naïve PDSCs, immortalized PDSCs and HepG2. FACS, ROS, caspase-3 assay, western blotting and immunofluorescence were performed to detect signalling events involved in self-renewal of the above cell types.
  
  
  RESULTS
  VCA had cancer cell-specific toxicity to HepG2 cells even with low concentrations of VCA (1-5 pg/ml), toxicity was observed to immortalized PDSCs and HepG2s, while proliferation of naïve PDSCs was significantly increased (P < 0.05). ROS production by VCA treatment in naïve PDSCs was significantly lower compared to controls (P < 0.05). Furthermore, autophagy was activated in naïve PDSCs treated with VCA through increase in type II LC3 and decrease in phosphorylated mTOR.
  
  
  CONCLUSIONS
  VCA can promote MSC proliferation through an activated autophagic mechanism.
authors.affiliation: Department of Biomedical Science, CHA University, Kangnak-ku, Seoul, South Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Choi
authors.forename: S Y
authors.initials: SY
authors.lastname: Lyu
authors.forename: H J
authors.initials: HJ
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Jung
authors.forename: W B
authors.initials: WB
authors.lastname: Park
authors.forename: G J
authors.initials: GJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D001343:Autophagy / Q000187:drug effects / Q000502:physiology*; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002461:Cell Line, Transformed; D005260:Female; D056945:Hep G2 Cells; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D010920:Placenta / Q000166:cytology; D037121:Plant Lectins / Q000494:pharmacology*; D011247:Pregnancy; D028182:Viscum album / Q000737:chemistry / Q000502:physiology*
chemical_list: D037121:Plant Lectins