title: Cytokine-induced killer cells showing multidrug resistance and remaining cytotoxic activity to tumor cells after transfected with mdr1 cDNA.
abstract: BACKGROUND
  Routine treatment of cancer such as surgery, radiation or chemotherapy is sometimes unable to eradicate metastatic malignant cells. So we tried a new method and increased the adoptive immunotherapy of Cytokine-induced killer (CIK) cells in tumor patients and the multidrug resistance (mdr1) cDNA was transfected into CIK cells.
  
  
  METHODS
  CIK cells were obtained from peripheral blood and induced by IFN-gamma, anti-CD3 monoclonal antibody, IL-2 and IL-1. CIK cells were transfected with plasmid PHaMDR containing human mdr1 cDNA by electroporation. RT-PCR was used to detect mdr1 mRNA in transfected CIK cells. P-glycoprotein (P-gp) expressed on surface of CIK cells was assayed by FITC-conjugated anti-P-gp monoclonal antibody and flow cytometry. Multidrug resistance to doxorubicin and colchicine and cytotoxic activity to human breast cancer cell line MCF7 were performed using MTT method.
  
  
  RESULTS
  mdr1 mRNA was detected in transfected CIK cells. P-gp was expressed on the surface of the transfected CIK cells, and the P-gp positive cells reached 21% - 37% of the total CIK cells after transfection. The IC50 to doxorubicin increased to 22.3 - 45.8 times, and that to colchicines to 6.7 - 11.35 times, as compared to those of untransfected CIK cells. However, the cytotoxic activity to MCF7 cell line remained unaltered.
  
  
  CONCLUSIONS
  CIK cells were successfully transfected with mdr1 cDNA by using electroporation. The transfected CIK cells had the characteristics of multidrug resistance without change in their cytotoxic activity to tumor cells.
authors.affiliation: The Department of Hemotology, First Hospital of Peking University, Beijing 100034, China. huifangli302003@yahoo.com.cn
authors.forename: Hui-fang
authors.initials: HF
authors.lastname: Li
authors.forename: Yong-hong
authors.initials: YH
authors.lastname: Yang
authors.forename: Yong-jin
authors.initials: YJ
authors.lastname: Shi
authors.forename: Yi-qun
authors.initials: YQ
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Zhu
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000502:physiology*; D017252:CD3 Complex / Q000032:analysis; D019002:CD56 Antigen / Q000032:analysis; D045744:Cell Line, Tumor; D016207:Cytokines / Q000494:pharmacology*; D003602:Cytotoxicity, Immunologic; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D017252:CD3 Complex; D019002:CD56 Antigen; D016207:Cytokines; D012333:RNA, Messenger