Theranostics 2013; 3(11):831-840. doi:10.7150/thno.6715
Genetically Encoded Immunophotosensitizer 4D5scFv-miniSOG is a Highly Selective Agent for Targeted Photokilling of Tumor Cells In Vitro
1. Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya, 16/10, Moscow, 117997, Russia;
2. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilova, 38, 119991 Moscow, Russia;
3. Research Institute of Applied and Fundamental Medicine, Nizhny Novgorod State Medical Academy, Nizhny Novgorod, Russia.
* These authors contributed equally to this work.
Mironova KE, Proshkina GM, Ryabova AV, Stremovskiy OA, Lukyanov SA, Petrov RV, Deyev SM. Genetically Encoded Immunophotosensitizer 4D5scFv-miniSOG is a Highly Selective Agent for Targeted Photokilling of Tumor Cells In Vitro. Theranostics 2013; 3(11):831-840. doi:10.7150/thno.6715. Available from http://www.thno.org/v03p0831.htm
Tumor-targeted delivery of cytotoxins presents considerable advantages over their passive transport. Chemical conjugation of cytotoxic module to antibody is limited due to insufficient reproducibility of synthesis, and recombinant immunotoxins are aimed to overcome this disadvantage. We obtained genetically encoded immunophotosensitizer 4D5scFv-miniSOG and evaluated its photocytotoxic effect in vitro. A single-chain variable fragment (scFv) of humanized 4D5 antibody was used as a targeting vehicle for selective recognition of the extracellular domain of human epidermal growth factor receptor 2 (HER2/neu) overexpressed in many human carcinomas. As a phototoxic module we used a recently described photoactivated fluorescent flavoprotein miniSOG. We found that recombinant protein 4D5scFv-miniSOG exerts a highly specific photo-induced cytotoxic effect on HER2/neu-positive human breast adenocarcinoma SK-BR-3 cells (IC50= 160 nM). We demonstrated that the 4D5scFv-miniSOG specifically binds to HER2-positive cells and internalizes via receptor-mediated endocytosis. Co-treatment of breast cancer cells with 4D5scFv-miniSOG and Taxol or junction opener protein JO-1 produced remarkable additive effects.
Keywords: tumor-targeted delivery, immunophototoxin, phototoxicity, HER2/neu, single-chain variable fragment.