Abstract：
Photodynamic therapy (PDT) is a therapeutic modality based on the simultaneous action of three elements: photosensitizer, light and oxygen. This triad generates singlet oxygen and reactive oxygen species that can reduce the mass of a tumor. PDT is also able to stimulate iNOS, the enzyme that generates nitric oxide (NO). The role of NO in PDT-treated cancer cells has been investigated in several studies. They showed that low iNOS/NO levels stimulate signaling pathways that promote tumor survival, while high iNOS/NO levels arrest tumor growth. There is increasing evidence that ROS/RNS control both proliferation and migration of cells in the vicinity of PDT-treated tumor cells (so-called bystander cells). In this work, we addressed the question of how NO, which is generated by weak PDT, affects bystander cells. We used a conditioned medium: medium of PDT-treated tumor cells containing the stressors produced by the cells was added to untreated cells mimicking the neighboring bystander cells to investigate whether the conditioned medium affects cell proliferation. We found that low-level NO in prostate cancer cells affects the bystander tumor cells in a manner that depends on their malignancy grade.
摘要：
光动力疗法（PDT）是一种基于三个元素同时作用的治疗方式：光敏剂，光和氧气该三联体产生可以减少肿瘤质量的单线态氧和活性氧。PDT也能刺激iNOS,产生一氧化氮（NO）的酶。已经在若干研究中研究了NO在PDT处理的癌细胞中的作用。他们表明低iNOS/NO水平刺激促进肿瘤存活的信号通路，而高iNOS/NO水平阻止肿瘤生长。越来越多的证据表明ROS/RNS控制PDT处理的肿瘤细胞(所谓的旁观者细胞)附近细胞的增殖和迁移。在这项工作中,我们解决了如何不的问题，它是由弱PDT产生的，影响旁观者细胞。我们使用条件培养基:将含有由细胞产生的应激源的PDT处理的肿瘤细胞的培养基添加到模拟邻近旁观者细胞的未处理的细胞中,以研究条件培养基是否影响细胞增殖。我们发现，前列腺癌细胞中低水平的NO以取决于其恶性程度的方式影响旁观者肿瘤细胞。
