Department Molecular Biology of Cell Cycle, Institute of Molecular Biology, Bulgarian Academy of Sciences, Acad. "G. Bonchev" Str., Bl. 21, Sofia 1113, Bulgaria.
Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
Photodiagnosis Photodyn Ther. 2016 Jun;14:9-17. doi: 10.1016/j.pdpdt.2016.01.012. Epub 2016 Feb 1.
Photodynamic therapy (PDT) is a noninvasive treatment for solid malignant and flat tumors. Light activated sensitizers catalyze photochemical reactions that produce reactive oxygen species which can cause cancer cell death. In this work we investigated the photophysical properties of the photosensitizer ruthenium(II) porphyrin (RuP), along with its PDT efficiency onto rat bladder cancer cells (AY27). Optical spectroscopy verified that RuP is capable to activate singlet oxygen via blue and red absorption bands and inter system crossing (ISC) to the triplet state. In vitro experiments on AY27 indicated increased photo-toxicity of RuP (20μM, 18h incubation) after cell illumination (at 435nm), as a function of blue light exposure. Cell survival fraction was significantly reduced to 14% after illumination of 20μM RuP with 15.6J/cm(2), whereas the "dark toxicity" of 20μM RuP was 17%. Structural and morphological changes of cells were observed, due to RuP accumulation, as well as light-dependent cell death was recorded by confocal microscopy. Flow cytometry verified that PDT-RuP (50μM) triggered significant photo-induced cellular destruction with a photoxicity of (93%±0.9%). Interestingly, the present investigation of RuP-PDT showed that the dominating mode of cell death is necrosis. RuP "dark toxicity" compared to the conventional chemotherapeutic drug cisplatin was higher, both evaluated by the MTT assay (24h). In conclusion, the present investigation shows that RuP with or without photoactivation induces cell death of bladder cancer cells.
光动力疗法（PDT）是一种治疗实体恶性和平坦肿瘤的非侵入性方法。光激活敏化剂催化光化学反应，产生活性氧物种，从而导致癌细胞死亡。在这项工作中，我们研究了光敏剂钌（II）卟啉（RuP）的光物理性质，以及其对大鼠膀胱癌细胞（AY27）的 PDT 效率。光学光谱证实，RuP 能够通过蓝光和红光吸收带以及系间窜越（ISC）到三重态激活单线态氧。体外实验表明，RuP（20μM，孵育 18 小时）在细胞照射（435nm）后，其光毒性增加，这是蓝光暴露的函数。在以 15.6J/cm(2)的剂量照射 20μM RuP 后，细胞存活分数显著降低至 14%，而 20μM RuP 的“暗毒性”为 17%。由于 RuP 的积累，观察到细胞的结构和形态变化，并且通过共聚焦显微镜记录了光依赖性细胞死亡。流式细胞术证实，PDT-RuP（50μM）引发了显著的光诱导细胞破坏，光毒性为（93%±0.9%）。有趣的是，RuP-PDT 的本研究表明，细胞死亡的主要模式是坏死。RuP 的“暗毒性”比传统的化疗药物顺铂更高，这两种药物都通过 MTT 测定法（24 小时）进行评估。总之，本研究表明 RuP 无论是否光激活都会诱导膀胱癌细胞死亡。
