Takahashi Junko, Misawa Masaki, Murakami Mami, Mori Takashi, Nomura Kazuki, Iwahashi Hitoshi
Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan.
Springerplus. 2013 Nov 12;2:602. doi: 10.1186/2193-1801-2-602. eCollection 2013.
5-Aminolevulinic acid (ALA) is a photosensitizer used in photodynamic therapy (PDT) because it causes preferential accumulation of protoporphyrin IX (PpIX) in tumor cells, where it forms singlet oxygen upon light irradiation and kills the tumor cells. Our previous study demonstrated that PpIX enhances generation of reactive oxygen species by physicochemical interaction with X-rays. We investigated the effect of ALA administration with X-ray irradiation of mouse B16-BL6 melanoma cells in vitro and in vivo. ALA facilitates PpIX accumulation in tumor cells and enhances ROS generation in vitro. Tumor suppression significantly improved in animals treated with fractionated doses of radiation (3 Gy × 10; total, 30 Gy) with local administration of 50 mg/kg ALA at 24 h prior to fractional irradiation. These results suggest ALA may improve the efficacy of cancer radiotherapy by acting as a radiomediator.
5-氨基酮戊酸（ALA）是一种用于光动力疗法（PDT）的光敏剂，因为它会使原卟啉IX（PpIX）在肿瘤细胞中优先蓄积，在光照下PpIX会形成单线态氧并杀死肿瘤细胞。我们之前的研究表明，PpIX通过与X射线的物理化学相互作用增强活性氧的生成。我们在体外和体内研究了ALA给药联合X射线照射小鼠B16-BL6黑色素瘤细胞的效果。ALA促进PpIX在肿瘤细胞中的蓄积，并在体外增强活性氧的生成。在分次照射前24小时局部给予50mg/kg ALA并进行分次剂量放疗（3Gy×10；总计30Gy）的动物中，肿瘤抑制效果显著改善。这些结果表明，ALA可能作为一种放疗介质提高癌症放疗的疗效。
