2017 Fiscal Year Final Research Report

Elucidation of the action mechanism of combined treatment with X-ray irradiation and 5-aminolevulinic acid by trantcriptome analysis

Research Project

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Project/Area Number	25293270
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Partial Multi-year Fund
Section	一般
Research Field	Radiation science
Research Institution	National Institute of Advanced Industrial Science and Technology
Principal Investigator	Takahashi Junko 国立研究開発法人産業技術総合研究所, 生命工学領域, 主任研究員 (80415702)
Co-Investigator(Kenkyū-buntansha)	森崇岐阜大学, 応用生物科学部, 教授 (40402218) 岩橋均岐阜大学, 応用生物科学部, 教授 (60356540)
Project Period (FY)	2013-04-01 – 2018-03-31
Keywords	放射線治療 / X線 / 放射線増感剤 / 5-アミノレブリン酸 / ポルフィリン / がん治療 / 放射線力学療法 / 光線力学療法
Outline of Final Research Achievements	Combined treatment with 5-aminolevulinic acid (ALA) and X-rays improves tumor suppression in vivo. This is because the accumulated protoporphyrin IX from ALA enhances the generation of ROS by the X-ray irradiation. In the present study, a high-energy medical linear accelerator was used instead of a non-medical low energy X-ray irradiator, which had been previously used. Tumor-bearing mice implanted with B16-BL6 melanoma cells were treated with fractionated doses of irradiation (in total, 20 or 30 Gy), using two types of X-ray irradiator after ALA administration. Suppression of tumor growth was enhanced with X-ray irradiation in combination with ALA treatment compared with X-ray treatment alone, using both medical and non-medical X-ray irradiators. “Radiodynamic therapy” using radiation from medical linacs as a physical driving force, rather than the light used in photodynamic therapy, may have potential clinical applications.
Free Research Field	医用生体工学
Academic Significance and Societal Importance of the Research Achievements	本課題の目標は、光線力学療法の励起メカニズムと類似しているが、光に替わりX線を用い、放射線の腫瘍選択性を高め、深部癌の治療に有効な「放射線力学療法」を開発し、今までの放射線治療では治療できなかったがんの治療に役立てることである。放射線力学療法に用いる放射線増感剤は低分子有機化合物であり、この様な化合物の放射線応答性に関する研究は独創的であり、世界的にも類似の研究はほとんど進められていない。