Chlorin e6 embedded in phospholipid nanoparticles equipped with specific peptides: Interaction with tumor cells with different aminopeptidase N expression.

A promising direction in Biopharmaceuticals is the development of specific peptide-based systems to improve drug delivery. This approach may increase tumor specificity and drug penetration into the target cell. Similar systems have been designed for several antitumor drugs. However, for photodynamic therapy drugs, such studies are not yet enough. Previously, we have developed a method of inclusion of chlorin e6 (Ce6), a photosensitizer used in photodynamic therapy, in phospholipid nanoparticles with a diameter of up to 30 nm, and reported an increase in its effectiveness in the experiments in vivo. In this work, we propose to modify a previously developed delivery system for Ce6 by the addition of cell-penetrating (R7) and/or targeting NGR peptides. The interaction of the compositions developed with HepG2 and MCF-7 tumor cells is shown. The expression of CD13 protein with affinity to NGR on the surface of these cells has been studied using flow cytometry. The expression of this protein on the HepG2 cells and its absence on MCF-7 was demonstrated. After incubation of tumor cells with the resulting Ce6 compositions, we evaluated the cellular accumulation, photoinduced, and dark cytotoxicity of the drugs. After irradiation, the highest level of cytotoxicity was observed when R7 peptide was added to the system, either alone or in combination with NGR. In addition to R7, the NGR-motif peptide increased the internalization of Ce6 in HepG2 cells without affecting its photodynamic activity. In this work we also discuss possible mechanisms of action of the cell-penetrating peptide when attached to phospholipid nanoparticles.

[Targeted drug delivery system for doxorubicin based on a specific peptide and phospholipid nanoparticles]. / Sistema adresnoi dostavki dlia doksorubitsina na osnove spetsificheskogo peptida i fosfolipidnykh nanochastits.

Doxorubicin is one of the widely known and frequently used chemotherapy drugs for the treatment of various types of cancer, the use of which is difficult due to its high cardiotoxicity. Targeted drug delivery systems are being developed to reduce side effects. One of the promising components as vector molecules (ligands) are NGR-containing peptides that are affinity for the CD13 receptor, which is expressed on the surface of many tumor cells and tumor blood vessels. Previously, a method was developed for preparing a composition of doxorubicin embedded in phospholipid nanoparticles with a targeted fragment in the form of an ultrafine emulsion. The resulting composition was characterized by a small particle size (less than 40 nm) and a high degree of incorporation of doxorubicin (about 93%) into transport nanoparticles. When assessing the penetrating ability and the degree of binding to the surface of fibrosarcoma cells (HT-1080), it was shown that when the composition with the targeted fragment was added to the cells, the level of doxorubicin was almost 2 times higher than that of the liposomal form of doxorubicin, i.e. the drug in the system with the targeted peptide penetrated the cell better. At the same time, on the control line of breast adenocarcinoma cells (MCF-7), which do not express the CD13 receptor on the surface, there was not significant difference in the level of doxorubicin in the cells. The data obtained allow us to draw preliminary conclusions about the prospects of targeted delivery of doxorubicin to tumor cells when using a peptide conjugate containing an NGR motif and the further need for its comprehensive study.