title: Gene delivery in malignant B cells using the combination of lentiviruses conjugated to anti-transferrin receptor antibodies and an immunoglobulin promoter.
abstract: BACKGROUND
  We previously developed an antibody-avidin fusion protein (ch128.1Av) specific for the human transferrin receptor 1 (TfR1; CD71) to be used as a delivery vector for cancer therapy and showed that ch128.1Av delivers the biotinylated plant toxin saporin-6 into malignant B cells. However, as a result of widespread expression of TfR1, delivery of the toxin to normal cells is a concern. Therefore, we explored the potential of a dual targeted lentiviral-mediated gene therapy strategy to restrict gene expression to malignant B cells. Targeting occurs through the use of ch128.1Av or its parental antibody without avidin (ch128.1) and through transcriptional regulation using an immunoglobulin promoter.
  
  
  METHODS
  Flow cytometry was used to detect the expression of enhanced green fluorescent protein (EGFP) in a panel of cell lines. Cell viability after specific delivery of the therapeutic gene FCU1, a chimeric enzyme consisting of cytosine deaminase genetically fused to uracil phosphoribosyltransferse that converts the 5-fluorocytosine (5-FC) prodrug into toxic metabolites, was monitored using the MTS or WST-1 viability assay.
  
  
  RESULTS
  We found that EGFP was specifically expressed in a panel of human malignant B-cell lines, but not in human malignant T-cell lines. EGFP expression was observed in all cell lines when a ubiquitous promoter was used. Furthermore, we show the decrease of cell viability in malignant plasma cells in the presence of 5-FC and the FCU1 gene.
  
  
  CONCLUSIONS
  The present study demonstrates that gene expression can be restricted to malignant B cells and suggests that this dual targeted gene therapy strategy may help to circumvent the potential side effects of certain TfR1-targeted protein delivery approaches.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
authors.forename: Lai Sum
authors.initials: LS
authors.lastname: Leoh
authors.forename: Kouki
authors.initials: K
authors.lastname: Morizono
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Kershaw
authors.forename: Irvin S Y
authors.initials: IS
authors.lastname: Chen
authors.forename: Manuel L
authors.initials: ML
authors.lastname: Penichet
authors.forename: Tracy R
authors.initials: TR
authors.lastname: Daniels-Wells
mesh_terms: D000906:Antibodies / Q000235:genetics / Q000276:immunology; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D045744:Cell Line, Tumor; D043525:Cytosine Deaminase / Q000235:genetics; D005437:Flucytosine / Q000378:metabolism; D015316:Genetic Therapy / Q000009:adverse effects; D005822:Genetic Vectors / Q000235:genetics / Q000627:therapeutic use; D049452:Green Fluorescent Proteins; D057809:HEK293 Cells; D006801:Humans; D019169:Jurkat Cells; D016086:Lentivirus / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics / Q000628:therapy; D010430:Pentosyltransferases / Q000235:genetics; D011355:Prodrugs / Q000009:adverse effects / Q000627:therapeutic use; D011401:Promoter Regions, Genetic; D011990:Receptors, Transferrin / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism; D014161:Transduction, Genetic; D014721:Vesicular stomatitis Indiana virus / Q000235:genetics
chemical_list: D000906:Antibodies; D015703:Antigens, CD; C068126:CD71 antigen; D011355:Prodrugs; D011990:Receptors, Transferrin; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D005437:Flucytosine; D010430:Pentosyltransferases; C023269:uracil phosphoribosyltransferase; D043525:Cytosine Deaminase
keywords: antibody; gene therapy; lentivirus; malignant B cells; prodrug therapy; transferrin receptor