Kuzichkina E O, Shilova O N, Deyev S M
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997 , Russia.
Acta Naturae. 2018 Oct-Dec;10(4):87-94.
The protein photosensitizer miniSOG is a promising agent for photodynamic therapy. The genetically encoded phototoxins 4D5scFv-miniSOG and DARPin-miniSOG specifically bind to the HER2 receptor overexpressed on the surface of cancer cells and promote receptor-mediated internalization of HER2. We show that ingestion of proteins in a complex with the receptor reduces the fluorescent signal of the phototoxic module in endosomes. In order to clarify the mechanism of decrease in the fluorescence intensity of miniSOG-based proteins as they enter a cancer cell during internalization, we analyzed the influence of different factors, including low pH, proteolysis, cofactor reduction, and shielding, on changes in the fluorescence of photosensitizers. Shielding and absorption of miniSOG fluorescence by cell fluorophores, including cytochrome c, were found to contribute significantly to the changes in the fluorescent properties of miniSOG.
蛋白质光敏剂miniSOG是一种很有前景的光动力治疗剂。基因编码的光毒素4D5scFv-miniSOG和DARPin-miniSOG特异性结合癌细胞表面过度表达的HER2受体，并促进HER2的受体介导内化。我们发现，摄入与该受体结合的复合物形式的蛋白质会降低内体中光毒性模块的荧光信号。为了阐明基于miniSOG的蛋白质在细胞内化过程中进入癌细胞时荧光强度降低的机制，我们分析了不同因素（包括低pH值、蛋白水解、辅因子还原和屏蔽）对光敏剂荧光变化的影响。发现包括细胞色素c在内的细胞荧光团对miniSOG荧光的屏蔽和吸收对miniSOG荧光特性的变化有显著贡献。
