title: Potent antitumour activity of the combination of HSV-TK and endostatin armed oncolytic adeno-associated virus for bladder cancer in vitro and in vivo.
abstract: BACKGROUND
  Gene therapy may offer a new tool for the treatment of bladder cancer. Previously, we have shown a significant antitumour effect in bladder cancer xenografts in a nude mouse model using intratumoural herpes simple virus thymidine (HSV-TK) and Endostatin gene therapy.
  
  
  OBJECTIVE
  Given the high vascularity of human bladder cancer and the ability of HSV-TK or Endostatin monotherapy to eradicate the tumours, we decided to test a novel combination of cytotoxicity and antiangiogenisis gene therapy using intratumourally delivered HSV-TK and Endostatin adeno-associated viruses (AAVs).
  
  
  METHODS
  We constructed plasmid AAV-TK-IRES-Endostatin (pAAV-TIE) and packaged the AAV particles contain gene fragments of HSV-TK and Endostatin. The function of HSV-TK and Endostatin was evaluated separately in vitro via T24 bladder tumour cells and human umbilical vein endothelial (HUVEC) cells. The combination anticancer effect of recombinant AAV-TIE (rAAV-TIE) was measured in vivo while rAAV-HSV-TK and rAAV-Endostatin as control groups.
  
  
  RESULTS
  In vitro, rAAV-TIE was found to induce a significant increase in apoptosis in HUVEC cells equally as rAAV-Endostatin and confirmed that the inhibition of endothelial cells mediated by rAAV-TIE was associated with the apoptotic process. rAAV-TIE was found to induce a significant increase in apoptosis in T24 cells equally as rAAV-HSV-TK and confirmed that the inhibition of T24 cells mediated by rAAV-TIE was associated with the apoptotic process too. In vivo, our results showed that the tumours in mice injected with the rAAV-TIE not only took significantly longer to emerge but also that their growth, once established, was significant slower than that of tumours grown, compared with single HSV-TK or Endostatin treated animals.
  
  
  CONCLUSIONS
  We concluded that the inhibition of angiogenesis using Endostatin gene transfer, together with the cytotoxicity HSV-TK gene therapy, resulted in a significant antitumour effect compared to the single gene based therapy in BTCC. The results warrant further development of the combination gene therapy, and suggest that this approach, directed towards systemic efficiency, could be used as an additional treatment for human BTCC.
authors.affiliation: The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China. thatdaypjg@163.com
authors.forename: Jian Gang
authors.initials: JG
authors.lastname: Pan
authors.forename: Xing
authors.initials: X
authors.lastname: Zhou
authors.forename: Ge Wa
authors.initials: GW
authors.lastname: Zeng
authors.forename: Rui Fa
authors.initials: RF
authors.lastname: Han
mesh_terms: D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D002470:Cell Survival; D000229:Dependovirus / Q000235:genetics*; D043169:Endostatins / Q000235:genetics*; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D061307:Human Umbilical Vein Endothelial Cells / Q000473:pathology; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009389:Neovascularization, Pathologic; D018139:Simplexvirus / Q000201:enzymology / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics*; D014162:Transfection; D001749:Urinary Bladder Neoplasms / Q000473:pathology / Q000628:therapy*
chemical_list: D043169:Endostatins; D013937:Thymidine Kinase