title: Reversal of chemoresistance with small interference RNA (siRNA) in etoposide resistant acute myeloid leukemia cells (HL-60).
abstract: BACKGROUND
  Overexpression of ATP-binding cassette (ABC) drug transporters is a major barrier in the success of cancer chemotherapy. One way to overcome overexpression of ABC drug transporter-mediated chemoresistance in acute myeloid leukemia is to suppress ABC drug transporter genes expression by small interference RNA (siRNA). In this study was assessed the involvement of ABCB1 gene in the mechanisms of resistance to etoposide in AML cells.
  
  
  METHODS
  The etoposide-resistant HL-60 cells were generated by stepwise exposure increasing concentrations of etoposide. The etoposide-resistant HL-60 cells were transfected with siRNAs using Transfection Reagent. The ABCB1 mRNA expression were assessed by real-time quantitative PCR. The MDR1/P-gp levels were measured by Western blotting. The sensitivity of resistant HL-60 cells to etoposide after transfection was determined using MTT assay. Apoptosis of resistant HL-60 cells after transfection was detected by flow cytometer.
  
  
  RESULTS
  It was found that siRNA effectively inhibited ABCB1 expression at both mRNA and protein levels. Knockdown of the ABCB1 gene correlated with increased sensitivity of the resistant HL-60 cells to etoposide and was observed to lower the cytotoxic index (IC50 etoposide value) after transfection.
  
  
  CONCLUSIONS
  Our results indicate that product of the ABCB1 gene have effective role in resistance to etoposide in acute myeloid leukemia cells.
authors.affiliation: Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: saeed.kachalaki@gmail.com.
authors.forename: Saeed
authors.initials: S
authors.lastname: Kachalaki
authors.affiliation: Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: baradaranb@tbzmed.ac.ir.
authors.forename: Behzad
authors.initials: B
authors.lastname: Baradaran
authors.affiliation: Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: jmajidiz@yahoo.com.
authors.forename: Jafar
authors.initials: J
authors.lastname: Majidi
authors.affiliation: Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: Yousefime@tbzmed.ac.ir.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Yousefi
authors.affiliation: Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: dariush_shanehbandi@yahoo.com.
authors.forename: Dariush
authors.initials: D
authors.lastname: Shanehbandi
authors.affiliation: Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: sina.mohammadinejada@gmail.com.
authors.forename: Sina
authors.initials: S
authors.lastname: Mohammadinejad
authors.affiliation: Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: b.mansoori_lab@yahoo.com.
authors.forename: Behzad
authors.initials: B
authors.lastname: Mansoori
mesh_terms: D064286:ATP Binding Cassette Transporter 1 / Q000235:genetics* / Q000378:metabolism; D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics / Q000378:metabolism; D000972:Antineoplastic Agents, Phytogenic / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005047:Etoposide / Q000378:metabolism / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic; D018922:HL-60 Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
chemical_list: C577836:ABCA1 protein, human; C513055:ABCB1 protein, human; D064286:ATP Binding Cassette Transporter 1; D018435:ATP Binding Cassette Transporter, Subfamily B; D000972:Antineoplastic Agents, Phytogenic; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D005047:Etoposide
keywords: ABCB1 gene; Chemosensitivity; Drug resistance; Etoposide; HL-60 cell; Small interference RNA