Combination effect of oncolytic adenovirus therapy and herpes simplex virus thymidine kinase/ganciclovir in hepatic carcinoma animal models.
OBJECTIVE
Oncolytic adenovirus, also called conditionally replicating adenovirus (CRAD), can selectively propagate in tumor cells and cause cell lysis. The released viral progeny can infect neighboring cancer cells, initiating a cascade that can lead to the ultimate destruction of the tumor. Suicide gene therapy using herpes simplex virus thymidine kinase (HSV-TK) and ganciclovir (GCV) offers a potential treatment strategy for cancer and is undergoing preclinical trials for a variety of tumors. We hypothesized that HSV-TK gene therapy combined with oncolytic adenoviral therapy would have an enhanced effect compared with the individual effects of the therapies and is a potential novel therapeutic strategy to treat liver cancer.


METHODS
To address our hypothesis, a novel CRAD was created, which consisted of a telomerase-dependent oncolytic adenovirus engineered to express E1A and HSV-TK genes (Ad-ETK). The combined effect of Ad-ETK and GCV was assessed both in vitro and in vivo in nude mice bearing HepG2 cell-derived tumors. Expression of the therapeutic genes by the transduced tumor cells was analyzed by RT-PCR and Western blotting.


RESULTS
We confirmed that Ad-ETK had antitumorigenic effects on human hepatocellular carcinoma (HCC) both in vitro and in vivo, and the TK/GCV system enhanced oncolytic adenoviral therapy. We confirmed that both E1A and HSV-TK genes were expressed in vivo.


CONCLUSIONS
The Ad-ETK construct should provide a relatively safe and selective approach to killing cancer cells and should be investigated as an adjuvant therapy for hepatocellular carcinoma.
Zheng
Fei-qun
FQ
Department of Interventional Therapy, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Peking University School of Oncology, Peking Cancer Hospital and Institute, Beijing, China.
Xu
Yin
Y
Yang
Ren-jie
RJ
Wu
Bin
B
Tan
Xiao-hua
XH
Qin
Yi-de
YD
Zhang
Qun-wei
QW
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000628:therapy*; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D015774:Ganciclovir / Q000008:administration & dosage*; D041722:Genes, Transgenic, Suicide; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D008114:Liver Neoplasms, Experimental / Q000628:therapy*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D050130:Oncolytic Virotherapy / Q000379:methods*; D018139:Simplexvirus / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics*
D013937:Thymidine Kinase; D015774:Ganciclovir