Radiation enhances adenoviral gene therapy in pancreatic cancer via activation of cytomegalovirus promoter and increased adenovirus uptake.
OBJECTIVE
Adenovirus-mediated gene therapy combined with radiation is expected to be a new approach to treat pancreatic cancer. However, there are no reports of definitive effects of radiation on adenovirus-mediated gene therapies. In the present study, we investigated the effect of radiation on the transduction efficiency of an adenovirus-based gene therapy.


METHODS
We used adenovirus expressing NK4 (Ad-NK4), an antagonist for hepatocyte growth factor, as a representative gene therapy. Pancreatic cancer cells preinfected with Ad-NK4 were irradiated, and NK4 levels in culture media of these cells were measured. We investigated cytomegalovirus (CMV) promoter activity and uptake of adenovirus in these cells. To examine the effect of radiation in vivo, Ad-NK4 was given to irradiated subcutaneous tumors in nude mice, and NK4 levels in tumors were measured.


RESULTS
NK4 levels in culture media of irradiated cells were 4.5-fold (P < 0.01) higher than those of nonirradiated cells. Radiation enhanced activation of the CMV promoter and adenovirus uptake (P < 0.01), leading to increased levels of NK4. We found that activation of p38 mitogen-activated protein kinase and up-regulation of dynamin 2 may be involved in the radiation-induced activation of the CMV promoter and adenovirus uptake, respectively. NK4 levels in irradiated tumors were 5.8-fold (P = 0.017) higher than those in nonirradiated tumors.


CONCLUSIONS
The present findings suggest that radiation significantly improves the efficiency of adenovirus-mediated gene transfer in pancreatic cancer and probably contributes to decreasing the dose of adenovirus required for gene transfer and controlling side effects of adenovirus infection in nonirradiated normal tissue.
Egami
Takuya
T
Department of Surgery and Oncology, Kyushu University, Fukuoka, Japan.
Ohuchida
Kenoki
K
Mizumoto
Kazuhiro
K
Onimaru
Manabu
M
Toma
Hiroki
H
Nishio
Shoko
S
Nagai
Eishi
E
Matsumoto
Kunio
K
Nakamura
Toshikazu
T
Tanaka
Masao
M
D000256:Adenoviridae / Q000235:genetics* / Q000502:physiology* / Q000528:radiation effects; D000818:Animals; D045744:Cell Line, Tumor; D003587:Cytomegalovirus / Q000235:genetics; D034285:Dynamin II / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000528:radiation effects; D017228:Hepatocyte Growth Factor / Q000235:genetics; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010190:Pancreatic Neoplasms / Q000628:therapy*; D010957:Plasmids / Q000528:radiation effects; D011401:Promoter Regions, Genetic / Q000528:radiation effects*; D014161:Transduction, Genetic; D053586:Virus Internalization / Q000528:radiation effects*; D023041:Xenograft Model Antitumor Assays
C066855:HGF protein, human; D017228:Hepatocyte Growth Factor; D034285:Dynamin II