アブストラクト（58巻1号：神奈川歯学）

神奈川歯学

Japanese

Title　： 光感受性物質を利用した口腔癌治療への光線力学療法の応用
Subtitle　： 神奈川歯科大学学会 第57回総会宿題報告
Authors　： 吉野文彦
Authors（kana）　：
Organization　： 神奈川歯科大学生体機能学講座歯科薬理学分野・准教授
Journal　： 神奈川歯学
Volume　： 58
Number　： 1
Page　： 61-64
Year/Month　： 2023 / 6
Article　： 報告
Publisher　： 神奈川歯科大学学会
Abstract　： 「緒言」 光線力学療法(Photodynamic Therapy; PDT)は, 細胞や組織に酸素依存性の効果をもたらすために組み合わされた, 無毒な2つのコンポーネントを含んでいる. PDTは, 二つの非毒性コンポーネントからなる療法法則であり, 対象の細胞や組織に酸素依存性の効果をもたらすことができる. その第一のコンポーネントは光増感剤(Photosensitizer; PS)であり, 対象の細胞や組織内に存在する光受容性分子である. 第二のコンポーネントは, PSを活性化させる特定の波長の光照射である. PSが光エネルギーを酸素分子に変換することで, 活性酸素種(Reactive Oxygen Species; ROS)を生成する反応は, 光を吸収した光増感剤の近傍で起こることが知られている. そのため, PSに対する生物学的反応は, 光が照射された組織の特定の部分でのみ活性化されると考えられている.
Practice　： 歯科学
Keywords　： 光線力学療法, 5-アミノレブリン酸, プロトポルフィリン, 青色光

English

Title　： The Utilization of Photodynamic Therapy with Photoreactive Substances for the Management of Oral Cancer
Subtitle　：
Authors　： Fumihiko YOSHINO
Authors（kana）　：
Organization　： Department of Pharmacology, Kanagawa Dental University
Journal　： Kanagawa Shigaku
Volume　： 58
Number　： 1
Page　： 61-64
Year/Month　： 2023 / 6
Article　： Report
Publisher　： Kanagawa Odontological Society
Abstract　： [Abstract] Photodynamic therapy (PDT) is a treatment modality that employs light of various wavelengths to activate photosensitizers (PSs), which generate reactive oxygen species (ROS) to exert an anti-tumor and bactericidal effect. Recently, research on PDT using 5-aminolevulinic acid (ALA), a porphyrin precursor that is thought to have fewer side effects (photosensitivity) than traditional PSs, has been conducted globally. ALA itself is not photosensitizing, but upon administration, it becomes the photosensitive protoporphyrin IX (PpIX) in mitochondria. Notably, the intracellular metabolic rate of ALA is significantly different between normal cells and cancer cells, with PpIX exhibiting a high accumulation in cancer tissues. This is a universal biological characteristic of cancer cells, and ALA-PDT, a technique that exploits this phenomenon, can be applied to almost all types of cancer. The history of PDT for oral cancer is short, and there have been few fundamental studies, with no studies of ALA-PDT for oral cancer focusing on blue light. In this study, my research team conducted a basic investigation of ALA-PDT for oral cancer with the aim of establishing a more effective PDT strategy for oral cancer by using blue light for ALA-PDT and optimizing the photoexcitation reaction of PpIX. The following experiments were performed using oral squamous cell carcinoma cell lines (HSC-3 and Ca9-22): (1) examination of the intracellular PpIX concentration following ALA treatment, (2) inhibition of PpIX to heme, (3) examination of the effect of additives on cell proliferation, and (4) examination of the cell-killing effect and oxidative stress induced by ALA-PDT. The intracellular PpIX concentration increased in an ALA concentration-dependent manner in both HSC-3 and Ca9- 22 cells following ALA treatment, with particularly high concentrations observed in the absence of serum and in the presence of DFX. No significant changes in cell proliferation were observed with the addition of various drugs. Blue and red light irradiation after cell culture demonstrated a significant cell-killing effect on Ca9-22 cells. Intracellular oxidative stress was increased by blue light irradiation compared to the non-irradiated group. These results suggest that ALA treatment increases PpIX in cancer cells and that blue light irradiation, in particular, generates intracellular ROS, which may have a cell-killing effect. Further in vivo studies using blue light in cancer cell transplantation are necessary to advance ALA-PDT.
Practice　： Dentistry
Keywords　：