CELLULAR & SUBCELLULAR MECHANISMS OF PHOTODYNAMIC THERAPY

在这个项目中，我们正在研究 光动力疗法(PDT)对肿瘤微观结构的影响。 具体地说，亚细胞定位和亚细胞 光动力疗法药物的光毒性正在研究中。最初，CPAE 内皮细胞和PTK2上皮细胞的可视化研究 细胞暴露于亚细胞时的细胞器荧光 5-氨基乙酰丙酸(ALA)。两种类型的细胞都显示出大量的 核周细胞质中的荧光，其中 光敏剂选择性地定位在线粒体中。至 亚细胞丙氨酸的亚细胞光毒性研究 用630 nm激光微束照射细胞区域。 结果表明，细胞核后为核周。 细胞质是细胞中最敏感的区域。尤其是 耐人寻味的是，发现细胞核是最敏感的 区域：1)核内未见荧光；2)核内未见荧光 人们普遍接受的光动力疗法损伤机制涉及单线态氧 以细胞质分子为靶标。根据这些发现，我们将 进一步研究其亚细胞定位和光毒性 ALA等PDT药物采用双光子激发。光动力疗法的激活 药物通过多光子吸收提供了比多光子吸收更大的选择性 单光子吸收。此外，双光子荧光将 允许改进细胞内药物分布的可视化， 尤其是沿光轴方向。

In this project we are investigating the fundamental mechanisms of photodynamic therapy (PDT) action on tumor microstructure. Specifically, the subcellular localization and subcellular phototoxicity of PDT drugs are being investigated. Initially, CPAE endothelial and PTK2 epithelial cells were studied by visualizing the subcellular organelle fluorescence when the cells were exposed to 5-aminolaevulinic acid (ALA). Both cell types showed a large amount of fluorescence in the perinuclear cytoplasm, where the photosensitizer selectively localized in the mitochondria. To investigate the subcellular phototoxicity of ALA, the subcellular regions of the cells were irradiated with a 630 nm laser microbeam. The results demonstrated that the nucleus followed by the perinuclear cytoplasm are the most sensitive areas of the cell. Particularly intriguing was the finding that the nucleus was the most sensitive region since 1) no fluorescence was observed in the nucleus and 2) th e generally accepted mechanism for PDT damage involve singlet oxygen targeting of cytoplasmic elements. Based upon these findings we will further investigate the subcellular localization and phototoxicity of ALA and other PDT drugs using 2-photon excitation. Activation of PDT drugs through multiphoton absorption provides greater selectivity than single photon absorption. in addition, the 2-photon fluorescence will allow improved visualization of drug distribution within the cell, especially along the optical axis.