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Background: Gene therapy may offer a new tool for the treatment of bladder cancer. Previously, we have shown a significant antitumor effect in bladder cancer xeno-grafts in a nude mouse model using intratumoral herpes simplex virus thymidine (HSV-TK) and endostatin gene monotherapy.
Methods: Given the high vascularity of human bladder cancer and the ability of HSV-TK or endostatin monotherapy to eradicate the tumors, we decided to test a novel combination of cytotoxic and antiangiogenic gene therapy using intratumorally delivered HSV-TK and endostatin adenoassociated viruses (AAV).
We constructed plasmid AAV-TK-IRES-Endostatin (pAAV-TIE) and packaged the AAV par-ticles containing gene fragments of HSV-TK and endostatin. The combined anticancer effect of recombinant AAV-TIE (rAAV-TIE) was measured in vivo with rAAV-HSV-TK and rAAV-Endostatin as the control groups.
Results: The inverted terminal repeat sequence was amplified using only one primer and the fragment between two ITRs of pAAV-TIE measuring about 4 kb, which indicated a stable sequence of pAAV-TIE. Three clear bands representing the AAV capsid proteins VP1, VP2, and VP3 could be seen on both lanes against a very low back-ground, which demonstrated that chloroform extraction could effectively extract con-taminants from rAAV stock without significant loss of the rAAV. In vivo, our re-sults showed that the tumors in mice injected with the rAAV-TIE not only took signi-ficantly longer to emerge but also that their growth, once established, was signi-ficant slower than that of tumors grown with single HSV-TK or endostatin treated animals.
Conclusions: We concluded that the inhibition of angiogenesis using endostatin gene transfer, together with the cytotoxic HSV-TK gene therapy, resulted in a signifi-cant antitumor effect compared to the single gene based therapy in BTCC.
DOI: 10.7754/Clin.Lab.2012.121109
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