The synthesis and investigation of a new bioconjugate for the targeted therapy of breast cancer is carried out. The ZHER2 scaffold polypeptide specific for the extracellular domain epitope of the HER2 transmembrane receptor, which is conjugated to a carrier molecule of human serum albumin (HSA) with the DOTA chelating agent attached to it, is used as the targeting agent. The radiolabeling reaction of the ZHER2–HSA–DOTA molecule is carried out with the 177Lu radionuclide, as well as with 212Pb, obtained using the developed laboratory generator. The radiochemical purity of the 177Lu-labeled preparation was 57 ± 10%, and that of the 212Pb-labeled preparation was 72 ± 5%. The degree of dissociative stability of these compounds was 73 ± 8% for 177Lu and more than 90% for 212Pb. In vitro tests of the cytotoxic activity of the obtained targeted radioactive compounds [177Lu]ZHER2–HSA–DOTA and [212Pb]ZHER2–HSA–DOTA in tumor-cell lines show a significant level of proliferation inhibition of the proliferation of human breast-cancer cells SK-BR-3 and BT474 with overexpression of the HER2/neu tumor marker in contrast to MCF-7 breast ductal adenocarcinoma cells with a low level of HER2/neu expression.

Today, it has become apparent that innovative treatment methods, including those involving simultaneous diagnosis and therapy, are particularly in demand in modern cancer medicine. The development of nanomedicine offers new ways of increasing the therapeutic index and minimizing side effects. The development of photoactivatable dyes that are effectively absorbed in the first transparency window of biological tissues (700900 nm) and are capable of fluorescence and heat generation has led to the emergence of phototheranostics, an approach that combines the bioimaging of deep tumors and metastases and their photothermal treatment. The creation of near-infrared (NIR) light-activated agents for sensitive fluorescence bioimaging and phototherapy is a priority in phototheranostics, because the excitation of drugs and/or diagnostic substances in the near-infrared region exhibits advantages such as deep penetration into tissues and a weak baseline level of autofluorescence. In this review, we focus on NIR-excited dyes and discuss prospects for their application in photothermal therapy and the diagnosis of cancer. Particular attention is focused on the consideration of new multifunctional nanoplatforms for phototheranostics which allow one to achieve a synergistic effect in combinatorial photothermal, photodynamic, and/or chemotherapy, with simultaneous fluorescence, acoustic, and/or magnetic resonance imaging.

Four variants of bifunctional HER2-specific recombinant proteins (anti-HER2-toxins) were created composed of HER2-specific scFv antibody (4D5scFv) or HER2-specific DARPin (D29) as targeting module and Pseudomonas exotoxin A fragment (PE40) as toxic module, and distinguished by the way of bacterial expression (cytoplasmic or periplasmic). Physicochemical, immunochemical, and functional properties of the created recombinant proteins as well as their expression yields were analyzed and compared with the option of the most promising one, D29-PE40, for further implementation as an agent for targeted therapy of HER2-overexpressing tumors.

In this review, the authors' works published within the past 5 years devoted to the development of bifunctional hybrid nanostructures based on the targeting polypeptides and nanoparticles of various origin (quantum dots, nanogold, nanodiamonds, upconversion nanoparticles, magnetic and polymer nanoparticles) as modules that ensure visualization and various damaging effects on cancer cells are surveyed and the prospects of their application in theranostics and precision medicine have been contemplated.

This mini-review summarizes recent data obtained in the process of creation of a versatile modular platform suitable for construction of supramolecular theranostic agents. As an example, we consider multifunctional hybrid agents for imaging and elimination of cancer cells. The use of an adapter protein system barnase:barstar for producing targeted multifunctional hybrid structures on the basis of highly specific peptides and mini-antibodies as addressing modules and recombinant proteins and/or nanoparticles of different natures (quantum dots, nanogold, magnetic nanoparticles, nanodiamonds, upconverting nanophosphors, polymer nanoparticles) as agents visualizing and damaging cancer cells is described. New perspectives for the creation of selective and highly effective compounds for theranostics and personified medicine are contemplated.

The review outlines progress and problems in the design of non-natural antibodies for clinical applications over the past 10-15 years. The modular structure of natural antibodies and approaches to its targeted modifications and combination with other structural elements and effector molecules are considered. The review covers modern methods for immunoglobulin engineering and promising strategies for the creation and applications of monoclonal antibodies, their derivatives and analogues, including abzymes and scaffolds, oriented to the use in the diagnosis and targeted therapy of cancer and other socially significant diseases.

Design and evaluation of new high-affinity protein compounds that can selectively and efficiently destroy human cancer cells are a priority research area in biomedicine. In this study we report on the ability of the recombinant phototoxic protein DARPin-miniSOG to interact with breast adenacarcinoma human cells overexpressing the extracellular domain of human epidermal growth factor receptor 2 (HER2). It was found that the targeted phototoxin DARPin-miniSOG specifically binds to the HER2 with following internalization and slow recycling back to the cell membrane. An insight into the role of DARPin-miniSOG in HER2 internalization could contribute to the treatment of HER2-positive cancer using this phototoxic protein.

Актуальным направлением в современной медицинской диагностике является создание нацеленных на патологические мишени конструкций на основе фотолюминесцентных наночастиц, обладающих высокой фото- и химической стабильностью, а также спектрами поглощения и испускания фотолюминесценции в области «окна прозрачности» биоткани. В работе получена двухкомпонентная конструкция на основе антистоксовых нанофосфoров (НАФ) и противоопухолевых мини-антител 4D5scFv для селективного мечения клеток, гиперэкспрессирующих опухолевый маркер HER2, характерный для целого ряда метастазирующих опухолей человека. Высокоаффинная белковая пара барстар : барназа (Bs : Bn), обладающая чрезвычайной устойчивостью в широком диапазоне pH и температур, использована в качестве молекулярного адаптера, обеспечивающего самосборку двухкомпонентной конструкции. На клетках аденокарциномы молочной железы человека SK-BR-3, гиперэкспрессирующих HER2, показана высокая избирательность связывания полученной двухкомпонентной конструкции 4D5scFv-Bn : Bs-НАФ с опухолевыми клетками. Предложенный подход позволяет получать аналогичные конструкции для визуализации различных специфических маркеров в патогенных тканях, в том числе в злокачественных новообразованиях.

The development of targeted constructs on the basis of photoluminescent nanoparticles with a high photo- and chemical stability and absorption/emission spectra in the "transparency window" of biological tissues is an important focus area of present-day medical diagnostics. In this work, a targeted two-component construct on the basis of upconversion nanophosphors (UCNPs) and anti-tumor 4D5 scFv was developed for selective labeling of tumor cells overexpressing the HER2 tumor marker characteristic of a number of human malignant tumors. A high affinity barnase : barstar (Bn : Bs) protein pair, which exhibits high stability in a wide range of pH and temperatures, was exploited as a molecular adapter providing self-assembly of the two-component construct. High selectivity for the binding of the two-component 4D5 scFv-Bn : UCNP-Bs construct to human breast adenocarcinoma SK-BR-3 cells overexpressing HER2 was demonstrated. This approach provides an opportunity to produce similar constructs for the visualization of different specific markers in pathogenic tissues, including malignant tumors.

General properties of the family of tyrosine kinase ERBB receptors are considered in connection with their role in the generation of cascades of signal transduction in normal and tumor cells. Causes of acquisition of oncogene features by genes encoding these receptors and their role in tumorigenesis are analyzed. Anti-ERBB monoclonal antibodies approved for therapy are described in detail, and mechanisms of their antitumor activity and development of resistance to them are reviewed. The existing and the most promising strategies for creating and using monoclonal antibodies and their derivatives for therapy of cancer are discussed.

Semiconductor quantum dots (QDs) are a new class of fluorophores with unique physical and chemical properties, which allow to appreciably expand the possibilities for the current methods of fluorescent imaging and optical diagnostics. Here we discuss the prospects of QD application for molecular diagnostics of tumors ranging from cancer-specific marker detection on microplates to non-invasive tumor imaging in vivo. We also point out the essential problems that require resolution in order to clinically promote QD, and we indicate innovative approaches to oncology which are implementable using QD.

Semiconductor quantum dots (QDs) are widely used in different fields of bioscience and biotechnology due to their unique optical properties. QDs can be used as fluorescent markers for optical detection and monitoring of deeply located tumors in vivo after specific labeling achieved by conjugating of QDs with targeting molecules. In this work the possibilities of intravital tumor labeling with QDs and subsequent in vivo tumor imaging were estimated. The experiments were run on immunodeficient nu/nu mice bearing human breast carcinoma SKBR-3, overexpressing surface protein HER2/neu. We used quantum dots Qdot 705 ITK (Invitrogen, USA) linked to anti-HER2/neu 4D5 scFv antibody. Antibody scFv fragments as a targeting agent for directed delivery of fluorophores possess significant advantages over full-size antibodies due to their small size, lower cross-reactivity and immunogenicity. QDs were bound to 4D5 scFv by barnase-barstar system (bn-bst) analogous to the streptavidin-biotidin system. Whole-body images were obtained using diffuse fluorescence tomography (DFT) setup with low-frequency modulation and transilluminative configuration of scanning, created at the Institute of Applied Physics of RAS (Russia). DFT-results were confirmed ex vivo by confocal microscopy. We report the results of in vivo whole-body tumor imaging with QDs complexes as contrasting agents. Intravital images of QDs-labeled tumors were obtained using specific tumor cells targeting and fluorescence transilluminative imaging method, while "passive" QD-labeling failed to mark effectively the tumor.