Tailoring protease-sensitive photodynamic agents to specific disease-associated enzymes
Tailoring protease-sensitive photodynamic agents to specific disease-associated enzymes
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DOI：
10.1021/bc060321l
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发表时间：
2007-07-01
影响因子：
4.7
通讯作者：
Lange, Norbert
中科院分区：
文献类型：
--
作者：
Gabriel, Doris;Campo, Marino A.;Lange, Norbert
我们开发了新型聚合物光敏剂前药(PPP)，用于改进光动力疗法。在PPP中，多个光敏剂单元通过蛋白酶可切割的多肽连接物共价偶联到聚合物骨架上。这些最初不具有光活性的化合物在特定的酶作用下裂解多肽连接物并随后释放光敏剂部分后变得荧光和光毒。通过短的和容易修饰的氨基酸序列将光敏剂连接到聚合物主干上，允许靶向各种不同的蛋白酶。对具有不同脱镁叶绿酸a肽负载率和主链净电荷的模型化合物进行了评估，考察了它们的溶解度、荧光发射的“自猝灭”能力和活性氧物种(ROS)的产生。此外，通过将PPP与具有类胰酶活性的不同酶孵育，或者通过在肽序列中引入单个D-精氨酸突变体，连接体序列削弱了对酶切割的选择性。体外细胞培养试验证实，在白光照射后，酶激活的PPP比未激活的结合物具有更高的光毒性，且具有剂量依赖性。这些数据表明，与疾病相关的蛋白酶相适应的类似化合物可以用于选择性光动力疗法。
We have developed novel polymeric photosensitizer prodrugs (PPPs) for improved photodynamic therapy. In PPPs, multiple photosensitizer units are covalently coupled to a polymeric backbone via protease-cleavable peptide linkers. These initially non-photoactive compounds become fluorescent and phototoxic after specific enzymatic cleavage of the peptide linkers and subsequent release of the photosensitizer moieties. Tethering the photosensitizer via a short and easily modified amino acid sequence to the polymeric backbone allows for the targeting of a wide variety of proteases. Model compounds, sensitive to trypsin-mediated cleavage, with different pheophorbide a-peptide loading ratios and backbone net charges were evaluated with respect to their solubility, "self-quenching" capacity of fluorescence emission, and reactive oxygen species (ROS) generation. In addition, linker sequence impaired selectivity toward enzymatic cleavage was demonstrated either by incubating PPPs with different enzymes having trypsin-like activity or by introducing a single D-arginine mutant in the peptide sequence. In vitro cell culture tests confirmed dose-dependent higher phototoxicity of enzymatically activated PPPs compared to the nonactivated conjugate after irradiation with white light. These data suggest that similar compounds adapted to disease-associated proteases can be used for selective photodynamic therapy.