Kuimova Marina K, Bhatti Manpreet, Deonarain Mahendra, Yahioglu Gokhan, Levitt James A, Stamati Ioanna, Suhling Klaus, Phillips David
Chemistry Department, Imperial College London, Exhibition Road, UK.
Photochem Photobiol Sci. 2007 Sep;6(9):933-9. doi: 10.1039/b708320c. Epub 2007 Aug 6.
We report the synthesis, spectroscopic properties and intracellular imaging of recombinant antibody single chain fragment (scFv) conjugates with photosensitizers used for photodynamic therapy of cancer (PDT). Two widely-studied photosensitizers have been selected: preclinical pyropheophorbide-a (PPa) and verteporfin (VP), which has been clinically approved for the treatment of acute macular degeneration (Visudyne). Pyropheophorbide-a and verteporfin have been conjugated to an anti-HER2 scFv containing on average ten photosensitizer molecules per scFv with a small contribution (<or=20%) from non-covalently bound molecules. Confocal fluorescence microscopy demonstrates good cellular uptake of PPa conjugate with the HER2-positive cell line, SKOV-3, while negligible cell uptake is demonstrated for the HER2-negative cell line, KB. For the VP conjugate, increased rate of cellular uptake and prolonged retention in SKOV-3 cells is observed compared to free photosensitizer. In clinical applications this could provide increased potency and desired selectivity towards malignant tissue, leaving surrounding healthy tissue unharmed and reducing skin photosensitivity. The present study highlights the usefulness of photosensitizer immunoconjugates with scFvs for targeted PDT.
我们报告了用于癌症光动力疗法（PDT）的重组抗体单链片段（scFv）与光敏剂缀合物的合成、光谱性质及细胞内成像。已选择两种广泛研究的光敏剂：临床前使用的焦脱镁叶绿酸-a（PPa）和已被临床批准用于治疗急性黄斑变性（维速达尔）的维替泊芬（VP）。焦脱镁叶绿酸-a和维替泊芬已与抗HER2 scFv缀合，每个scFv平均含有十个光敏剂分子，非共价结合分子的贡献较小（≤20%）。共聚焦荧光显微镜显示，PPa缀合物在HER2阳性细胞系SKOV-3中具有良好的细胞摄取，而在HER2阴性细胞系KB中细胞摄取可忽略不计。对于VP缀合物，与游离光敏剂相比，观察到SKOV-3细胞中细胞摄取率增加且保留时间延长。在临床应用中，这可以提高对恶性组织的效力和所需的选择性，使周围健康组织不受损害并降低皮肤光敏性。本研究突出了光敏剂与scFv免疫缀合物在靶向PDT中的有用性。
