title: Autophagy Attenuates MnCl2-induced Apoptosis in Human Bronchial Epithelial Cells.
abstract: OBJECTIVE
  To investigate the role of autophagy in MnCl2-induced apoptosis in human bronchial epithelial 16HBE cells.
  
  
  METHODS
  Cell proliferation was measured by MTT assay. Mitochondrial membrane potential (MMP) and apoptosis were measured by flow cytometry. Autophagic vacuoles were detected by fluorescence microscopy. Cellular levels of apoptosis and autophagy-related proteins were measured by western blotting.
  
  
  RESULTS
  16HBE cell proliferation was inhibited by MnCl2 in a dose- and time-dependent manner. MnCl2-induced 16HBE cell growth inhibition was related to MMP depolarization prior to the induction of apoptosis. Our data revealed that MnCl2-induced apoptosis in 16HBE cells was mediated by decreased expression of Bcl-2 and increased levels of cleaved caspase-3. It was observed that when we exposed 16HBE cells to MnCl2 in a dose-dependent manner, the formation of autophagic vacuoles and the levels of LC-3B-II were elevated. RNA interference of LC3B in these MnCl2-exposed cells demonstrated that MMP loss and apoptosis were enhanced. Additionally, the pan-caspase inhibitor Z-VAD-FMK increased the cellular levels of Bcl-2 and decreased apoptosis, but did not affect the cellular levels of LC3B in MnCl2-treated 16HBE cells.
  
  
  CONCLUSIONS
  MnCl2 dose- and time-dependently inhibits 16HBE cell proliferation and induces MMP loss and apoptosis. Autophagy acts in a protective role against MnCl2-induced apoptosis in 16HBE cells.
authors.affiliation: Department of Toxicology, Peking University Health Science Center, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Zhun
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: Department of Toxicology, Shanghai Municipal Center for Disease Control & Prevention, Shanghai 200336, China.
authors.forename: Xian Ping
authors.initials: XP
authors.lastname: Ying
authors.affiliation: Department of Toxicology, Shanghai Municipal Center for Disease Control & Prevention, Shanghai 200336, China.
authors.forename: Wei Jian
authors.initials: WJ
authors.lastname: Zhong
authors.affiliation: Chinese Academy of Inspection and Quarantine Comprehensive Test Center, Beijing 100123, China.
authors.forename: Shi Min
authors.initials: SM
authors.lastname: Tian
authors.affiliation: Department of Toxicology, Peking University Health Science Center, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Medical and Healthy Analytical Center, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Yong Rui
authors.initials: YR
authors.lastname: Jia
authors.affiliation: Department of Toxicology, Faculty of Preventive Medicine, School of Public Health, Sun Yat-sen University, Guangzhou 510080, Guangdong, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Toxicology, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Juan Ling
authors.initials: JL
authors.lastname: Fu
authors.affiliation: Department of Toxicology, Peking University Health Science Center, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.affiliation: Department of Toxicology, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Zong Can
authors.initials: ZC
authors.lastname: Zhou
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects / Q000502:physiology*; D001980:Bronchi; D002460:Cell Line; D002712:Chlorides / Q000494:pharmacology*; D015536:Down-Regulation; D004847:Epithelial Cells / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D017895:Manganese Compounds / Q000494:pharmacology*
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D002712:Chlorides; D017895:Manganese Compounds; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C025340:manganese chloride
keywords: 16HBE cells; Apoptosis; Autophagy; Manganese chloride; Mitochondrial membrane potential