title: Dichloroacetate induces protective autophagy in LoVo cells: involvement of cathepsin D/thioredoxin-like protein 1 and Akt-mTOR-mediated signaling.
abstract: Dichloroacetate (DCA) is an inhibitor of pyruvate dehydrogenase kinase (PDK), and recently it has been shown as a promising nontoxic antineoplastic agent. In this study, we demonstrated that DCA could induce autophagy in LoVo cells, which were confirmed by the formation of autophagosomes, appearance of punctate patterns of LC3 immunoreactivity and activation of autophagy associated proteins. Moreover, autophagy inhibition by 3-methyladenine (3-MA) or Atg7 siRNA treatment can significantly enhance DCA-induced apoptosis. To determine the underlying mechanism of DCA-induced autophagy, target identification using drug affinity responsive target stability (DARTS) coupled with ESI-Q-TOF MS/MS analysis were utilized to profile differentially expressed proteins between control and DCA-treated LoVo cells. As a result, Cathepsin D (CTSD) and thioredoxin-like protein 1 (TXNL1) were identified with significant alterations compared with control. Further study indicated that DCA treatment significantly promoted abnormal reactive oxygen species (ROS) production. On the other hand, DCA-triggered autophagy could be attenuated by N-acetyl cysteine (NAC), a ROS inhibitor. Finally, we demonstrated that the Akt-mTOR signaling pathway, a major negative regulator of autophagy, was suppressed by DCA treatment. To our knowledge, it was the first study to show that DCA induced protective autophagy in LoVo cells, and the potential mechanisms were involved in ROS imbalance and Akt-mTOR signaling pathway suppression.
authors.affiliation: 1] Department of Gynecology and Obstetrics, Second West China Hospital; Cancer center, West China hospital, Sichuan University, Chengdu, China [2] State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, China.
authors.forename: F
authors.initials: F
authors.lastname: Gong
authors.forename: X
authors.initials: X
authors.lastname: Peng
authors.forename: Y
authors.initials: Y
authors.lastname: Sang
authors.forename: M
authors.initials: M
authors.lastname: Qiu
authors.forename: C
authors.initials: C
authors.lastname: Luo
authors.forename: Z
authors.initials: Z
authors.lastname: He
authors.forename: X
authors.initials: X
authors.lastname: Zhao
authors.forename: A
authors.initials: A
authors.lastname: Tong
mesh_terms: D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D002402:Cathepsin D / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003999:Dichloroacetic Acid / Q000494:pharmacology*; D045325:HCT116 Cells; D006801:Humans; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; C504766:TXNL1 protein, human; D013879:Thioredoxins; D003999:Dichloroacetic Acid; C546842:MTOR protein, human; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D002402:Cathepsin D