title: Chloroquine-induced glioma cells death is associated with mitochondrial membrane potential loss, but not oxidative stress.
abstract: Chloroquine (CQ), a quinolone derivative widely used to treat and prevent malaria, has been shown to exert a potent adjuvant effect when combined with conventional glioblastoma therapy. Despite inducing lysosome destabilization and activating p53 in human glioma cells, the mechanisms underlying cell death induced by this drug are poorly understood. Here, we analyzed in a time- and dose-dependent manner, the effects of CQ upon mitochondria integrity, autophagy regulation and redox processes in four human glioma cell lines that differ in their resistance to this drug. NAC-containing media protected cells against CQ-induced loss of mitochondrial membrane potential (MMP), autophagic vacuoles (LC3II) accumulation and loss of cell viability induced by CQ. However, we noticed that part of this protection was due to media acidification in NAC preparations, alerting for problems in experimental procedures using NAC. The results indicate that although CQ induces accumulation of LC3II, mitochondria, and oxidative stress, neither of these events is clearly correlated to cell death induced by this drug. The only event elicited in all cell lines at equitoxic doses of CQ was the loss of MMP, indicating that mitochondrial stability is important for cells resistance to this drug. Finally, the data indicate that higher steady-state MMP values can predict cell resistance to CQ treatment.
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil. Electronic address: alexandre.vessoni@usp.br.
authors.forename: Alexandre Teixeira
authors.initials: AT
authors.lastname: Vessoni
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil. Electronic address: annabel.quinet@usp.br.
authors.forename: Annabel
authors.initials: A
authors.lastname: Quinet
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil. Electronic address: leolima11@gmail.com.
authors.forename: Leonardo Carmo
authors.initials: LC
authors.lastname: de Andrade-Lima
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil.
authors.forename: Davi Jardim
authors.initials: DJ
authors.lastname: Martins
authors.affiliation: Núcleo de Pesquisa em Ciências Biológicas & Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, 35400-000 Minas Gerais, MG, Brazil. Electronic address: carriao.camila@gmail.com.
authors.forename: Camila Carrião Machado
authors.initials: CC
authors.lastname: Garcia
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil. Electronic address: calsmah@yahoo.com.br.
authors.forename: Clarissa Ribeiro Reily
authors.initials: CR
authors.lastname: Rocha
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil. Electronic address: deborabv@hotmail.com.
authors.forename: Debora Braga
authors.initials: DB
authors.lastname: Vieira
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil. Electronic address: cfmmenck@usp.br.
authors.forename: Carlos Frederico Martins
authors.initials: CF
authors.lastname: Menck
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002738:Chloroquine / Q000494:pharmacology*; D005910:Glioma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D002738:Chloroquine; D000111:Acetylcysteine
keywords: Autophagy; Chloroquine; Glioma; Glutathione; Mitochondrial membrane potential; Oxidative stress