Worthington J, Robson T, O'Keeffe M, Hirst D G
Radiation Science Research Group, School of Biomedical Sciences, University of Ulster, Newtownabbey, Co. Antrim, UK.
Gene Ther. 2002 Feb;9(4):263-9. doi: 10.1038/sj.gt.3301609.
Nitric oxide (NO()) has many characteristics including cytotoxicity, radiosensitization and anti-angiogenesis, which make it an attractive molecule for use in cancer therapy. We have investigated the use of iNOS gene transfer, driven by both a constitutive (CMV) and X-ray inducible (WAF1) promoter, for generating high concentrations of NO() within tumour cells. We have combined this treatment with radiation to exploit the radiosensitizing properties of this molecule. Transfection of murine RIF-1 tumour cells in vitro with the iNOS constructs resulted in increased iNOS protein levels. Under hypoxic conditions cells were radiosensitized by delivery of both constructs so that these treatments effectively eliminated the radioresistance observed under hypoxic conditions. In vivo transfer of the CMV/iNOS construct by direct tumour injection resulted in a delay (4.2 days) in tumour growth compared with untreated controls. This was equivalent to the effect of 20 Gy X-rays alone. Combination of CMV/iNOS gene transfer with 20 Gy X-rays resulted in a dramatic 19.8 day growth delay compared with controls. Tumours treated with the CMV/iNOS showed large areas of necrosis and abundant apoptosis. We believe that iNOS gene transfer has the potential to be a highly effective treatment in combination with radiotherapy.
一氧化氮（NO()）具有多种特性，包括细胞毒性、放射增敏作用和抗血管生成作用，这些特性使其成为癌症治疗中一个有吸引力的分子。我们研究了由组成型（CMV）和X射线诱导型（WAF1）启动子驱动的诱导型一氧化氮合酶（iNOS）基因转移，用于在肿瘤细胞内产生高浓度的NO()。我们将这种治疗方法与放疗相结合，以利用该分子的放射增敏特性。用iNOS构建体体外转染小鼠RIF-1肿瘤细胞导致iNOS蛋白水平升高。在缺氧条件下，两种构建体的递送都使细胞对放疗敏感，因此这些治疗有效地消除了缺氧条件下观察到的放射抗性。通过直接肿瘤注射进行CMV/iNOS构建体的体内转移导致与未治疗的对照相比肿瘤生长延迟（4.2天）。这相当于单独20 Gy X射线的效果。CMV/iNOS基因转移与20 Gy X射线联合使用导致与对照相比肿瘤生长延迟显著延长19.8天。用CMV/iNOS治疗的肿瘤显示出大面积坏死和大量凋亡。我们认为，iNOS基因转移有可能与放疗联合成为一种高效的治疗方法。
