Department of Neurosurgery, University Hospital Muenster, Muenster, Germany.
Institute of Neuropathology, University Hospital Muenster, Muenster, Germany.
Neurosurgery. 2018 Dec 1;83(6):1328-1337. doi: 10.1093/neuros/nyy054.
Light irradiation (635 nm) of cells containing protoporphyrin IX (PPIX) after 5- aminolevulinic acid (5-ALA) pretreatment causes cell death via different pathways including apoptosis and necrosis, as previously demonstrated for malignant glioma cells.
To elucidate whether various malignant pediatric brain tumors, which have been shown to accumulate PPIX, would also be susceptible to photodynamic therapy (PDT).
Medulloblastoma (DAOY, UW228), pNET (PFSK-1), and rhabdoid tumor (BT16) cell lines were incubated with 5-ALA in variable concentrations for 4 h. Consequently, cells were irradiated by 635 nm diode laser light. After 12 h, cell viability was measured by WST-1 testing and these results were compared to control cells incubated with 5-ALA without irradiation or irradiation only without prior incubation with 5-ALA.
We demonstrated significant cell death in malignant pediatric tumor cells after incubation with 5-ALA and laser irradiation in comparison to control groups. In all cell lines, we noticed significant cell death above a 5-ALA concentration of 50 μg/ml (P < .05). Neither 5-ALA incubation alone nor irradiation alone caused cell death. DAOY and PFSK cell lines were more susceptible than UW228 and BT16 cells.
We conclude that PDT causes cell death with higher PPIX concentrations after exposure to 5-ALA in vitro in accordance to similar studies with glioma cells. This indicates that PDT might be feasible for eliminating brain tumor cells in malignant pediatric brain tumors. Additionally, we noticed a dependency between fluorescence intensity and death rates.
经 5- 氨基酮戊酸（5-ALA）预处理后的含原卟啉 IX（PPIX）细胞在 635nm 光照射下会通过不同途径导致细胞死亡，包括凋亡和坏死，这在恶性神经胶质瘤细胞中已有证实。
阐明先前已证明可积累 PPIX 的各种恶性小儿脑肿瘤是否也易受光动力疗法（PDT）的影响。
将髓母细胞瘤（DAOY、UW228）、pNET（PFSK-1）和横纹肌样瘤（BT16）细胞系在不同浓度的 5-ALA 中孵育 4 小时。随后，用 635nm 二极管激光照射细胞。12 小时后，通过 WST-1 检测法测量细胞活力，并将这些结果与未经照射的 5-ALA 孵育的对照细胞或仅照射而未经 5-ALA 孵育的对照细胞进行比较。
与对照组相比，我们在孵育 5-ALA 和激光照射后发现恶性小儿肿瘤细胞出现明显的细胞死亡。在所有细胞系中，我们发现 5-ALA 浓度高于 50μg/ml 时均出现明显的细胞死亡（P<0.05）。单独孵育 5-ALA 或单独照射均不会导致细胞死亡。DAOY 和 PFSK 细胞系比 UW228 和 BT16 细胞系更敏感。
我们的结论是，PDT 会导致细胞死亡，其方式是在体外经 5-ALA 暴露后 PPIX 浓度升高，与类似的胶质瘤细胞研究一致。这表明 PDT 可能可用于消除恶性小儿脑肿瘤中的脑肿瘤细胞。此外，我们注意到荧光强度与死亡率之间存在依赖性。
