title: Tetrandrine is a potent cell autophagy agonist via activated intracellular reactive oxygen species.
abstract: BACKGROUND
  Autophagy is an evolutionarily conserved cellular process that involves the lysosomal degradation of proteins and organelles and the recycling of cellular components to ensure cellular survival under external or internal stress. Numerous data has indicated that autophagy can be successfully targeted for the treatment of multiple cancers. We have previously demonstrated that tetrandrine, a bisbenzylisoquinoline alkaloid isolated from the broadly used Chinese medicinal herb Stephaniae tetrandrae, exhibits potent antitumor effects when used either alone or in combination with other drugs.
  
  
  RESULTS
  In the present study, we showed that tetrandrine is a broad-spectrum potent autophagy agonist. Although low-dose tetrandrine treatment does not affect cell viability, it can potently induce autophagy in a variety of cell lines, including cancerous cells and nontumorigenic cells. The autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ), effectively blocked tetrandrine-induced autophagy. Moreover, tetrandrine significantly triggered the induction of mitophagy. The underlying mechanisms are associated with the tetrandrine-induced production of intracellular reactive oxygen species (ROS), which plays a critical role in tetrandrine-induced autophagy.
  
  
  CONCLUSIONS
  Here, we report that tetrandrine is a potent cell autophagy agonist and may have a wide range of applications in the fields of antitumor therapy and basic scientific research.
authors.affiliation: College of Life Sciences, Wuhan University, Wuhan, 430072 P R China.
authors.forename: Haiqing
authors.initials: H
authors.lastname: Wang
authors.affiliation: College of Life Sciences, Wuhan University, Wuhan, 430072 P R China.
authors.forename: Ting
authors.initials: T
authors.lastname: Liu
authors.affiliation: College of Life Sciences, Wuhan University, Wuhan, 430072 P R China.
authors.forename: Lu
authors.initials: L
authors.lastname: Li
authors.affiliation: College of Life Sciences, Wuhan University, Wuhan, 430072 P R China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.affiliation: College of Life Sciences, Wuhan University, Wuhan, 430072 P R China.
authors.forename: Chunrong
authors.initials: C
authors.lastname: Yu
authors.affiliation: Ministry of Education Laboratory of Combinatorial Biosynthesis and Drug Discovery, College of pharmacy, Wuhan University, Wuhan, 430072 P R China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Life Sciences, Wuhan University, Wuhan, 430072 P R China.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Li
keywords: Autophagy; Reactive oxygen species; Tetrandrine