title: Intranasal interleukin-12 gene therapy enhanced the activity of ifosfamide against osteosarcoma lung metastases.
abstract: BACKGROUND
  Cyclophosphamide (CTX) and ifosfamide (IFX) are alkylating agents used to treat osteosarcoma (OS). It was previously demonstrated that the sensitivity of OS cells to 4-hydroperoxycyclophosphamide (4-HC, the active metabolite of CTX) is augmented by interleukin (IL)-12 in vitro through a mechanism involving the Fas/FasL pathway. The purpose of these studies was to determine whether this synergistic effect is operational in vivo.
  
  
  METHODS
  Mice were injected intravenously with human LM7 osteosarcoma cells. Treatment was initiated with IFX (2.5 mg/kg intraperitoneally) with or without intranasal polyethylenimine (PEI):IL-12 gene therapy given twice weekly for 6 weeks.
  
  
  RESULTS
  Expression of IL-12 protein in the lung was demonstrated in all mice receiving intranasal PEI:IL-12 but not in control mice or those treated with IFX alone. Increased expression of FasL was detected in lungs of all mice receiving IFX. Both IFX and PEI:IL-12 alone significantly inhibited lung metastasis when compared with control groups (P < 0.05). However, the most significant tumor effect was observed in mice receiving IFX+PEI:IL-12 (P < 0.01). Immunohistochemical staining for CD31 and basic fibroblast growth factor (bFGF) and the number of proliferating cells as quantified by proliferating cell nuclear antigen (PCNA) staining were also most significantly decreased in mice receiving combination therapy.
  
  
  CONCLUSIONS
  These data indicate that combining IFX and IL-12 may have therapeutic potential and that this increased efficacy may be mediated through a mechanism involving the Fas/FasL pathway.
authors.affiliation: Division of Pediatrics, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Duan
authors.forename: Shu-Fang
authors.initials: SF
authors.lastname: Jia
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Koshkina
authors.forename: Eugenie S
authors.initials: ES
authors.lastname: Kleinerman
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use*; D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D003131:Combined Modality Therapy; D004357:Drug Synergism; D053222:Fas Ligand Protein; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D007069:Ifosfamide / Q000627:therapeutic use*; D018664:Interleukin-12 / Q000235:genetics* / Q000378:metabolism; D008175:Lung Neoplasms / Q000378:metabolism / Q000556:secondary / Q000628:therapy*; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D012516:Osteosarcoma / Q000378:metabolism / Q000556:secondary / Q000628:therapy*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D011094:Polyethyleneimine / Q000627:therapeutic use; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D048069:Tumor Necrosis Factors / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism
chemical_list: D018906:Antineoplastic Agents, Alkylating; C505661:FASLG protein, human; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008562:Membrane Glycoproteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D048069:Tumor Necrosis Factors; D019014:fas Receptor; D016222:Fibroblast Growth Factor 2; D018664:Interleukin-12; D011094:Polyethyleneimine; D007069:Ifosfamide