title: Emodin ameliorates cisplatin-induced apoptosis of rat renal tubular cells in vitro by activating autophagy.
abstract: OBJECTIVE
  A previous report shows that emodin extracted from the Chinese herbs rhubarb and giant knotweed rhizome can ameliorate the anticancer drug cisplatin-induced injury of HEK293 cells. In this study, we investigated whether and how emodin could protect renal tubular epithelial cells against cisplatin-induced nephrotoxicity in vitro.
  
  
  METHODS
  The viability and apoptosis of normal rat renal tubular epithelial cells (NRK-52E) were detected using formazan assay and flow cytometry analysis, respectively. The expression levels of cleaved caspase-3, autophagy maker LC3 I/II, and AMPK/mTOR signaling pathway-related proteins were measured with Western blot analysis. The changes of morphology and RFP-LC3 fluorescence were observed under microscopy.
  
  
  RESULTS
  Cisplatin (10-50 μmol/L) dose-dependently induced cell damage and apoptosis in NRK-52E cells, whereas emodin (10 and 100 μmol/L) significantly ameliorated cisplatin-induced cell damage, apoptosis and caspase-3 cleavage. Emodin dose-dependently increased LC3-II levels and induced RFP-LC3-containing punctate structures in NRK-52E cells. Furthermore, the protective effects of emodin were abolished by bafilomycin A1 (10 nmol/L), and mimicked by rapamycin (100 nmol/L). Moreover, emodin increased the phosphorylation of AMPK and suppressed the phosphorylation of mTOR. The AMPK inhibitor compound C (10 μmol/L) not only abolished emodin-induced autophagy activation, but also emodin-induced anti-apoptotic effects.
  
  
  CONCLUSIONS
  Emodin ameliorates cisplatin-induced apoptosis of rat renal tubular cells in vitro through modulating the AMPK/mTOR signaling pathways and activating autophagy. Emodin may have therapeutic potential for the prevention of cisplatin-induced nephrotoxicity.
authors.affiliation: Department of Nephrology, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210029, China.|Department of Graduate School, Nanjing University of Chinese Medicine, Nanjing 210046, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.affiliation: Center for Diabetes Care, Education and Research, Jiangsu Province Institute of Geriatrics, Nanjing 210024, China.
authors.forename: Liu-bao
authors.initials: LB
authors.lastname: Gu
authors.affiliation: Department of Graduate School, Nanjing University of Chinese Medicine, Nanjing 210046, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Tu
authors.affiliation: Department of Graduate School, Nanjing University of Chinese Medicine, Nanjing 210046, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Molecular Signaling, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Yan-ru
authors.initials: YR
authors.lastname: Huang
authors.affiliation: Department of Nephrology, The Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210029, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects*; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D002945:Cisplatin / Q000009:adverse effects*; D004642:Emodin / Q000494:pharmacology*; D006801:Humans; D007684:Kidney Tubules / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D020011:Protective Agents / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D020011:Protective Agents; D047428:Protein Kinase Inhibitors; D058570:TOR Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; D053148:Caspase 3; D004642:Emodin; D002945:Cisplatin