title: Baculovirus vector-mediated transfer of sodium iodide symporter and plasminogen kringle 5 genes for tumor radioiodide therapy.
abstract: BACKGROUND
  Both tumor cells and their supporting endothelial cells should be considered for targeted cell killing when designing cancer treatments. Here we investigated the feasibility of combining radioiodide and antiangiogenic therapies after baculovirus-mediated transfer of genes encoding the sodium iodide symporter (NIS) and plasminogen kringle 5 (K5).
  
  
  METHODS
  A recombinant baculovirus containing the NIS gene under control of the human telomerase reverse transcriptase (hTERT) promoter and the K5 gene driven by the early growth response 1 (Egr1) promoter was developed. Dual-luciferase reporter assay was performed to confirm the activation of hTERT transcription. NIS and K5 gene expression were identified by Western blot and Real-Time PCR. Functional NIS activity in baculovirus-infected Hela cells was confirmed by the uptake of 125I and cytotoxicity of 131I. The apoptotic effect of 131I-induced K5 on baculovirus-infected human umbilical vein endothelial cells (HUVECs) was analyzed by a flow cytometry-based assay. In vivo, NIS reporter gene imaging and therapeutic experiments with 131I were performed. Finally, the microvessel density (MVD) in tumors after treatment was determined by CD31 immunostaining.
  
  
  RESULTS
  The activation of hTERT transcription was specifically up-regulated in tumor cells. NIS gene expression markedly increased in baculovirus-infected HeLa cells, but not in MRC5 cells. The Hela cells showed a significant increase of 125I uptake, which was inhibited by NaClO4, and a notably decreased cell survival rate by 131I treatment. Expression of the K5 gene induced by 131I was elevated in a dose- and time-dependent manner and resulted in the apoptosis of HUVECs. Furthermore, 131I SPECT imaging clearly showed cervical tumor xenografts infected with recombinant baculovirus. Following therapy, tumor growth was significantly retarded. CD31 immunostaining confirmed a significant decrease of MVD.
  
  
  CONCLUSIONS
  The recombinant baculovirus supports a promising strategy of NIS-based raidoiodide therapy combined with K5-based antiangiogenic therapy by targeting both the tumor and its supporting vessels.
authors.affiliation: Department of Nuclear Medicine, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Nuclear Medicine, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Guo
authors.affiliation: Department of Nuclear Medicine, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Shi
authors.affiliation: Department of Nuclear Medicine, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Miao
authors.affiliation: Department of Nuclear Medicine, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Nuclear Medicine, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Li
mesh_terms: D016367:Baculoviridae / Q000235:genetics*; D045744:Cell Line, Tumor; D005260:Female; D005822:Genetic Vectors / Q000235:genetics*; D006367:HeLa Cells; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007457:Iodine Radioisotopes / Q000378:metabolism / Q000627:therapeutic use*; D010446:Peptide Fragments / Q000235:genetics* / Q000502:physiology; D010958:Plasminogen / Q000235:genetics* / Q000502:physiology; D011401:Promoter Regions, Genetic; D011859:Radiography; D027981:Symporters / Q000235:genetics* / Q000502:physiology; D019098:Telomerase / Q000235:genetics; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays; D000099209:Sodium-Iodide Symporters
chemical_list: D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D010958:Plasminogen; D027981:Symporters; D019098:Telomerase; D000099209:Sodium-Iodide Symporters; C491499:plasminogen kringle 5; C509186:TERT protein, human