title: 7-Ketocholesterol overcomes drug resistance in chronic myeloid leukemia cell lines beyond MDR1 mechanism.
abstract: Chronic myeloid leukemia (CML) is a myeloproliferative disease with a characteristic BCR-ABL tyrosine kinase (TK) fusion protein. Despite the clinical efficacy accomplished by TKIs therapies, disease progression may affect patient response rate to these inhibitors due to a multitude of factors that could lead to development of a mechanism known as multidrug resistance (MDR). 7-Ketocholesterol (7KC) is an oxidized cholesterol derivative that has been extensively reported to cause cell death in a variety of cancer models. In this study, we showed the in vitro efficacy of 7KC against MDR leukemia cell line, Lucena. 7KC treatment induced reduction in cell viability, together with apoptosis-mediated cell death. Moreover, downregulation of MDR protein caused intracellular drug accumulation and 7KC co-incubation with either Daunorubicin or Vincristine reduced cell viability compared to the use of each drug alone. Additionally, quantitative label-free mass spectrometry-based protein quantification showed alteration of different molecular pathways involved in cell cycle arrest, induction of apoptosis and misfolded protein response. Conclusively, this study highlights the effect of 7KC as a sensitizing agent of multidrug resistance CML and elucidates its molecular mechanisms.
  
  
  
  CML patients treated with tyrosine kinase inhibitors (TKIs) have showed a 5-year estimated overall survival of 89%, with cumulative complete cytogenetic response of 87%. However, development of drug resistance is a common feature of the disease progression. This study aimed at showing the effect of 7KC as a cytotoxic and sensitizing agent of multidrug resistance CML cell lines. The cellular and molecular basis of this compound were elucidated using a comprehensive strategy based on quantitative proteomic and cell biology assays. We showed that 7KC induced cell death and overcomes drug resistance in CML through mechanisms that go beyond the classical MDR1 pathways.
authors.affiliation: Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo Medical School (FMUSP), São Paulo, Brazil.
authors.forename: Lívia
authors.initials: L
authors.lastname: Rosa Fernandes
authors.affiliation: Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo Medical School (FMUSP), São Paulo, Brazil.
authors.forename: Ana Carolina Bassi
authors.initials: AC
authors.lastname: Stern
authors.affiliation: Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo Medical School (FMUSP), São Paulo, Brazil.
authors.forename: Rita de Cássia
authors.initials: RC
authors.lastname: Cavaglieri
authors.affiliation: Proteomic Unit, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Fábio César Sousa
authors.initials: FC
authors.lastname: Nogueira
authors.affiliation: Proteomic Unit, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Domont
authors.affiliation: GlycoProteomics Laboratory, Department of Parasitology, ICB, University of Sao Paulo, Brazil. Electronic address: palmisano.gp@usp.br.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Palmisano
authors.affiliation: Laboratory of Genetics and Molecular Hematology (LIM31), University of São Paulo Medical School (FMUSP), São Paulo, Brazil. Electronic address: spbydlow@usp.br.
authors.forename: Sérgio Paulo
authors.initials: SP
authors.lastname: Bydlowski
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor; D003630:Daunorubicin / Q000627:therapeutic use; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004357:Drug Synergism; D006801:Humans; D007653:Ketocholesterols / Q000494:pharmacology* / Q000627:therapeutic use; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy*; D040901:Proteomics / Q000379:methods; D057165:Proteostasis Deficiencies / Q000378:metabolism; D014750:Vincristine / Q000627:therapeutic use
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D007653:Ketocholesterols; D014750:Vincristine; C003001:7-ketocholesterol; D003630:Daunorubicin
keywords: Cell death and 7-ketocholesterol; Chronic myeloid leukemia; Multidrug resistance; Oxysterols; Quantitative proteomics