Egami Takuya, Ohuchida Kenoki, Mizumoto Kazuhiro, Onimaru Manabu, Toma Hiroki, Nishio Shoko, Nagai Eishi, Matsumoto Kunio, Nakamura Toshikazu, Tanaka Masao
Department of Surgery and Oncology, Kyushu University, Fukuoka, Japan.
Clin Cancer Res. 2008 Mar 15;14(6):1859-67. doi: 10.1158/1078-0432.CCR-07-0933.
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.
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.
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.
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.
腺病毒介导的基因治疗联合放疗有望成为治疗胰腺癌的新方法。然而，尚无关于放疗对腺病毒介导的基因治疗的确切影响的报道。在本研究中，我们调查了放疗对基于腺病毒的基因治疗转导效率的影响。
我们使用表达肝细胞生长因子拮抗剂NK4的腺病毒（Ad-NK4）作为代表性基因治疗。对预先感染Ad-NK4的胰腺癌细胞进行放疗，并测量这些细胞培养基中的NK4水平。我们研究了这些细胞中巨细胞病毒（CMV）启动子活性和腺病毒摄取情况。为了研究放疗在体内的作用，将Ad-NK4给予裸鼠经放疗的皮下肿瘤，并测量肿瘤中的NK4水平。
放疗细胞培养基中的NK4水平比未放疗细胞高4.5倍（P < 0.01）。放疗增强了CMV启动子的激活和腺病毒摄取（P < 0.01），导致NK4水平升高。我们发现p38丝裂原活化蛋白激酶的激活和发动蛋白2的上调可能分别参与了放疗诱导的CMV启动子激活和腺病毒摄取。放疗肿瘤中的NK4水平比未放疗肿瘤高5.8倍（P = 0.017）。
本研究结果表明，放疗可显著提高腺病毒介导的胰腺癌基因转移效率，可能有助于减少基因转移所需的腺病毒剂量，并控制腺病毒感染在未放疗正常组织中的副作用。
