Adeno-associated virus mediated endostatin gene therapy in combination with topoisomerase inhibitor effectively controls liver tumor in mouse model.
OBJECTIVE
rAAV mediated endostatin gene therapy has been examined as a new method for treating cancer. However, a sustained and high protein delivery is required to achieve the desired therapeutic effects. We evaluated the impact of topoisomerase inhibitors in rAAV delivered endostatin gene therapy in a liver tumor model.


METHODS
rAAV containing endostatin expression cassettes were transduced into hepatoma cell lines. To test whether the topoisomerase inhibitor pretreatment increased the expression of endostatin, Western blotting and ELISA were performed. The biologic activity of endostatin was confirmed by endothelial cell proliferation and tube formation assays. The anti-tumor effects of the rAAV-endostatin vector combined with a topoisomerase inhibitor, etoposide, were evaluated in a mouse liver tumor model.


RESULTS
Topoisomerase inhibitors, including camptothecin and etoposide, were found to increase the endostatin expression level in vitro. The over-expressed endostatin, as a result of pretreatment with a topoisomerase inhibitor, was also biologically active. In animal experiments, the combined therapy of topoisomerase inhibitor, etoposide with the rAAV-endostatin vector had the best tumor-suppressive effect and tumor foci were barely observed in livers of the treated mice. Pretreatment with an etoposide increased the level of endostatin in the liver and serum of rAAV-endostatin treated mice. Finally, the mice treated with rAAV-endostatin in combination with etoposide showed the longest survival among the experimental models.


CONCLUSIONS
rAAV delivered endostatin gene therapy in combination with a topoisomerase inhibitor pretreatment is an effective modality for anticancer gene therapy.
Hong
Sung-Yi
SY
Department of Surgery, Yonsei University College of Medicine, Youngdong PO Box 1217, Seoul, Korea.
Lee
Myun-Hee
MH
Kim
Kyung-Sup
KS
Jung
Hyun-Cheol
HC
Roh
Jae-Kyung
JK
Hyung
Woo-Jin
WJ
Noh
Sung-Hoon
SH
Choi
Seung-Ho
SH
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D002166:Camptothecin / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000401:mortality; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D004357:Drug Synergism; D043169:Endostatins / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005047:Etoposide / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000401:mortality; D051379:Mice; D012509:Sarcoma / Q000188:drug therapy* / Q000401:mortality; D015996:Survival Rate; D059003:Topoisomerase Inhibitors; D014471:Umbilical Veins / Q000166:cytology
D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; D043169:Endostatins; D004791:Enzyme Inhibitors; D059003:Topoisomerase Inhibitors; D005047:Etoposide; D002166:Camptothecin