title: Adeno-associated virus-mediated doxycycline-regulatable TRAIL expression suppresses growth of human breast carcinoma in nude mice.
abstract: BACKGROUND
  Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) functions as a cytokine to selectively kill various cancer cells without toxicity to most normal cells. Numerous studies have demonstrated the potential use of recombinant soluble TRAIL as a cancer therapeutic agent. We have showed previous administration of a recombinant adeno-associated virus (rAAV) vector expressing soluble TRAIL results in an efficient suppression of human tumor growth in nude mice. In the present study, we introduced Tet-On gene expression system into the rAAV vector to control the soluble TRAIL expression and evaluate the efficiency of the system in cancer gene therapy.
  
  
  METHODS
  Controllability of the Tet-On system was determined by luciferase activity assay, and Western blotting and enzyme-linked immunoabsorbent assay. Cell viability was determined by MTT assay. The breast cancer xenograft animal model was established and recombinant virus was administrated through tail vein injection to evaluate the tumoricidal activity.
  
  
  RESULTS
  The expression of soluble TRAIL could be strictly controlled by the Tet-On system in both normal and cancer cells. Transduction of human cancer cell lines with rAAV-TRE-TRAIL&rAAV-Tet-On under the presence of inducer doxycycline resulted in a considerable cell death by apoptosis. Intravenous injection of the recombinant virus efficiently suppressed the growth of human breast carcinoma in nude mice when activated by doxycycline.
  
  
  CONCLUSIONS
  These data suggest that rAAV-mediated soluble TRAIL expression under the control of the Tet-On system is a promising strategy for breast cancer therapy.
authors.affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Zheng
authors.forename: Zhang
authors.initials: Z
authors.lastname: Weilun
authors.forename: Jiang
authors.initials: J
authors.lastname: Minghong
authors.forename: Zhang
authors.initials: Z
authors.lastname: Yaxi
authors.forename: Liu
authors.initials: L
authors.lastname: Shilian
authors.forename: Liu
authors.initials: L
authors.lastname: Yanxin
authors.forename: Zheng
authors.initials: Z
authors.lastname: Dexian
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002277:Carcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D000229:Dependovirus / Q000235:genetics*; D004318:Doxycycline / Q000494:pharmacology; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000235:genetics* / Q000378:metabolism; D047368:Tumor Burden
chemical_list: D053221:TNF-Related Apoptosis-Inducing Ligand; D004318:Doxycycline