title: Use of thymidine kinase gene-modified endothelial progenitor cells as a vector targeting angiogenesis in glioma gene therapy.
abstract: OBJECTIVE
  The poor prognosis of patients with glioma is due to infiltrative growth of glioma cells, which correlates with their ability to induce angiogenesis. Tumor angiogenesis is supported by the mobilization and functional incorporation of endothelial progenitor cells (EPCs). The aim of this study was to propose the use of gene-modified EPCs as a vector system that allowed systemic gene delivery into multiple areas of tumor angiogenesis for glioma therapy.
  
  
  METHODS
  Thymidine kinase (TK) gene-modified EPCs were mixed with glioma cells or human umbilical vein endothelial cells (HUVECs) at varying ratios for ganciclovir in vitro. Cell proliferation was evaluated by MTT assay, and apoptosis was examined by annexin-V and phosphatidylserine (propidium iodide) staining. EPCs were injected via tail vein into nude mice bearing glioma, and EPC incorporation into the tumor was determined immunohistochemically. The antitumor effects of TK gene-modified EPCs in vivo were evaluated by apoptosis assay and microvessel density analysis.
  
  
  RESULTS
  TK gene-modified EPCs exerted a potent bystander effect on glioma cells and HUVECs by induction of apoptosis via caspase activation in vitro. EPCs incorporated preferentially into glioma vasculatures. Furthermore, TK gene-modified EPCs clearly augmented the antitumor effect by inhibition of angiogenesis following repeated intravenous injection in vivo.
  
  
  CONCLUSIONS
  The results indicate the feasibility of EPC-based gene delivery into disseminated areas of tumor angiogenesis as a rational strategy for glioma gene therapy.
authors.affiliation: Department of Neurosurgery, First Affiliated Hospital, Nanjing Medical University, Nanjing, PR China.
authors.forename: Jun-xia
authors.initials: JX
authors.lastname: Zhang
authors.forename: Chun-sheng
authors.initials: CS
authors.lastname: Kang
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.forename: Ning
authors.initials: N
authors.lastname: Liu
authors.forename: Yong-ping
authors.initials: YP
authors.lastname: You
mesh_terms: D000071916:AC133 Antigen; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology; D005312:Fetal Blood / Q000166:cytology; D015774:Ganciclovir / Q000494:pharmacology; D015316:Genetic Therapy / Q000379:methods*; D005910:Glioma / Q000235:genetics / Q000628:therapy*; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000517:prevention & control*; D010455:Peptides / Q000032:analysis; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology / Q000201:enzymology*; D013937:Thymidine Kinase / Q000235:genetics* / Q000378:metabolism; D014183:Transplantation, Heterologous; D014471:Umbilical Veins
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; D010455:Peptides; D013937:Thymidine Kinase; D015774:Ganciclovir