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The efficiency of the binding of tumor-targeting phage particles displaying tumor-targeting peptides, which were obtained with phage-display technology, to the U-87 MG human glioblastoma cell line and healthy, DKM-5 human embryo brain cells has been evaluated via flow cytometry and enzyme-linked immunosorbent assay. The specific binding of the selected bacteriophages to U-87 MG cells was shown via fluorescence microscopy. Based on the obtained data, the tumor-targeting phage particles that provide the most efficient in vitro binding to the U-87 MG cells were selected for further studies in order to create targeted antitumor compounds. [ABSTRACT FROM AUTHOR]

Brain tumors are among the most intractable types of malignant neoplasms. Despite advances in the treatment of cancer, in particular, the development of new approaches in surgery, radiotherapy and chemotherapy, the incidence remains high with a low 5-year survival rate. Targeted therapy (TT) may be a solution to the problem of low efficacy of the applied cancer treatment methods. TT is based on the use of drugs that specifically affect specific types of tumors, which allows one to increase the effectiveness of treatment and minimize toxic effects on healthy tissues of the body. The combination of the unique properties of cancer cells allows one to find specific ligands that interact directly with the tumor, and to conduct TT for malignant tumors. Phage display technology is one of the promising approaches to the search for tissue- and/or organ-specific molecules [1]. Combinatorial phage peptide libraries make it possible to obtain highly specific peptides, including for various types of tumors. Currently, such tumor-targeting peptides are considered as means of targeted delivery of therapeutic genes, cytokines, imaging agents, pro-apoptotic peptides, and cytotoxic drugs. The purpose of this work was to obtain from the phage peptide library of bacteriophages exposing peptides, which ensure the accumulation of phage particles in human glioblastoma cells U-87 MG, and to assess the specificity of the selected peptides for cells of the primary cultures of human gliomas. During the research, the following tasks were solved: (1) Tumor-targeting peptides were selected using human glioblastoma cells U-87 MG in vitro and on a U-87 MG tumor in a xenograft model in vivo; amino acid sequences of selected peptides (SWTFGVQFALQH (26), HPSSGSA (92), PVSNKMS (83)) were determined; (2) primary cultures of human gliomas AS2, MG1, MG2, MG3, MG4 cells were obtained and characterized; (3) specificity of the binding of bacteriophages exposing selected tumor-targeting peptides to cells of primary cultures of human gliomas was evaluated using immunocytochemical analysis. The specific binding of selected tumor-targeting peptides with cells of the primary cultures AS2, MG1 was shown. [ABSTRACT FROM AUTHOR]

Earlier, a pro-apoptotic peptide lactaptin was isolated from human milk and characterized and its recombinant analogue RL2 was generated. Both peptides were demonstrated to be capable of apoptotic cell death induction in human breast adenocarcinoma MCF-7 cells. In the work, biochemical markers of RL2-induced MCF-7 apoptosis are analyzed. Activation of initiator and effector caspases, as well as apoptotic changes in mitochondrial membrane potential and cytoplasm membrane composition in cells treated with RL2, were analyzed using flow cytometry and Western blot techniques. MCF-7 cell death induced by RL2 was found to be associated with phosphatidylserine exposure on the surface of the plasma membrane. Also, RL2 was demonstrated to induce dissipation of the mitochondrial membrane potential and activation of initiator caspases 8 and 9 and an effector caspase 7. [ABSTRACT FROM AUTHOR]