A novel HER2-specific sensor based on DARPin_9-29 and albumin binding domain for real-time fluorescence-guided tumor detection in animal model of cancer.

In animal models of cancer, targeted fluorescence bioimaging, performed non-invasively and in real time, is indispensable tool for assessing tumor location, spread of metastasis, and the therapeutic potential of anticancer drugs under development. To overcome the limitation of antibodies in bioimaging applications, small artificial scaffold proteins based on ankyrin repeats (DARPins, designed ankyrin repeat proteins) are used as tumor-associated antigen binders. In this study for the first time, we assessed the potential of DARPin_9-29, the human epidermal growth factor receptor 2 (HER2) subdomain I-specific protein, genetically fused with albumin binding domain (ABD) and conjugated with Cyanine5.

The Barnase-Barstar-based pre-targeting strategy for enhanced antitumor therapy in vivo.

There is a great need for novel approaches to the treatment of epithelial ovarian carcinoma, which is the leading cause of mortality from gynecological malignancies. In this study, the pre-targeting technology was used to enhance the in vivo targeting of cytotoxic module composed of nanoliposomes loaded with a truncated form of Pseudomonas aeruginosa exotoxin A (PE40) to cancer cells. Pre-targeting system used in this study is composed of bacterial ribonuclease Barnase and its natural antitoxin Barstar.

A Vector Nanoplatform for the Bioimaging of Deep-Seated Tumors.

Today, in preclinical studies, optical bioimaging based on luminescence and fluorescence is indispensable in studying the development of neoplastic transformations, the proliferative activity of the tumor, its metastatic potential, as well as the therapeutic effect of antitumor agents. In order to expand the capabilities of optical imaging, sensors based on the bioluminescence resonance energy transfer (BRET) mechanism and, therefore, independent of an external light source are being developed. A targeted nanoplatform based on HER2-specific liposomes whose internal environment contains a genetically encoded BRET sensor was developed in this study to visualize deep-seated tumors characterized by overexpression of human epidermal growth factor receptor type 2 (HER2).

Genetically engineered CD80-pMHC-harboring extracellular vesicles for antigen-specific CD4 T-cell engagement.

The identification of low-frequency antigen-specific CD4 T cells is crucial for effective immunomonitoring across various diseases. However, this task still encounters experimental challenges necessitating the implementation of enrichment procedures. While existing antigen-specific expansion technologies predominantly concentrate on the enrichment of CD8 T cells, advancements in methods targeting CD4 T cells have been limited.

System for Self-excited Targeted Photodynamic Therapy Based on the Multimodal Protein DARP-NanoLuc-SOPP3.

Despite the significant potential of photodynamic therapy (PDT) as a minimally invasive treatment modality, the use of this method in oncology has remained limited due to two serious problems: 1) limited penetration of the excitation light in tissues, which makes it impossible to affect deep-seated tumors and 2) use of chemical photosensitizers that slowly degrade in the body and cause photodermatoses and hyperthermia in patients. To solve these problems, we propose a fully biocompatible targeted system for PDT that does not require an external light source. The proposed system is based on bioluminescent resonance energy transfer (BRET) from the oxidized form of the luciferase substrate to the photosensitizing protein SOPP3.

HER2-specific liposomes loaded with proteinaceous BRET pair as a promising tool for targeted self-excited photodynamic therapy.

Photodynamic therapy (PDT) for deep-seated tumors is still challenging due to the limited penetration of visible light through tissues. To resolve this limitation, systems based on bioluminescence resonance energy transfer (BRET), that do not require an external light source are proposed. Herein, for BRET-activated PDT we developed proteinaceous BRET-pair consisting of luciferase NanoLuc, which acts as energy donor upon addition of luciferase specific substrate furimazine, and phototoxic protein SOPP3 as a photosensitizer.

Selective targeting of α7 nicotinic acetylcholine receptor by synthetic peptide mimicking loop I of human SLURP-1 provides efficient and prolonged therapy of epidermoid carcinoma .

α7-Type nicotinic acetylcholine receptor (α7-nAChR) promotes the growth and metastasis of solid tumors. Secreted Ly6/uPAR-Related Protein 1 (SLURP-1) is a specific negative modulator of α7-nAChR produced by epithelial cells. Here, we investigated mechanisms of antiproliferative activity of recombinant SLURP-1 in epidermoid carcinoma A431 cells and activity of SLURP-1 and synthetic 21 a.

Polymer/magnetite carriers functionalized by HER2-DARPin: Avoiding lysosomes during internalization and controlled toxicity of doxorubicin by focused ultrasound induced release.

Nanomedicine has revolutionized the available treatment options during the last decade, but poor selectivity of targeted drug delivery and release is still poses a challenge. In this study, doxorubicin (DOX) and magnetite nanoparticles were encapsulated by freezing-induced loading, coated with polymeric shell bearing two bi-layers of polyarginine/dextran sulphate and finally modified with HER2-specific DARPin proteins. We demonstrated that the enhanced cellular uptake of these nanocarriers predominantly occurs by SKOV-3 (HER2+) cells, in comparison to CHO (HER2-) cells, together with the controlled DOX release using low intensity focused ultrasound (LIFU).

Novel Small Multilamellar Liposomes Containing Large Quantities of Peptide Nucleic Acid Selectively Kill Breast Cancer Cells.

Peptide nucleic acid (PNA) may be used in various biomedical applications; however, these are currently limited, due to its low solubility in aqueous solutions. In this study, a methodology to overcome this limitation is demonstrated, as well as the effect of PNA on cell viability. We show that extruding a mixture of natural phospholipids and short (6-22 bases), cytosine-rich PNA through a 100 nm pore size membrane under mild acidic conditions resulted in the formation of small (60-90 nm in diameter) multilamellar vesicles (SMVs) comprising several (3-5) concentric lipid membranes.

Genetically encoded BRET-activated photodynamic therapy for the treatment of deep-seated tumors.

Photodynamic therapy (PDT) is one of the most appealing photonic modalities for cancer treatment based on anticancer activity of light-induced photosensitizer-mediated reactive oxygen species (ROS), but a limited depth of light penetration into tissues does not make possible the treatment of deep-seated neoplasms and thus complicates its widespread clinical adoption. Here, we introduce the concept of genetically encoded bioluminescence resonance energy transfer (BRET)-activated PDT, which combines an internal light source and a photosensitizer (PS) in a single-genetic construct, which can be delivered to tumors seated at virtually unlimited depth and then triggered by the injection of a substrate to initiate their treatment. To illustrate the concept, we engineered genetic NanoLuc-miniSOG BRET pair, combining NanoLuc luciferase flashlight and phototoxic flavoprotein miniSOG, which generates ROS under luciferase-substrate injection.

Barnase-Barstar Pair: Contemporary Application in Cancer Research and Nanotechnology.

Barnase is an extracellular ribonuclease secreted by that was originally studied as a small stable enzyme with robust folding. The identification of barnase intracellular inhibitor barstar led to the discovery of an incredibly strong protein-protein interaction. Together, barnase and barstar provide a fully genetically encoded toxin-antitoxin pair having an extremely low dissociation constant.

Barnase*Barstar-guided two-step targeting approach for drug delivery to tumor cells in vivo.

For precise ligation of a targeting and cytotoxic moiety, the use of Barnase-Barstar pair as a molecular glue is proposed for the first time. Targeting was mediated through the use of a scaffold protein DARPin_9-29 specific for the human epidermal receptor 2 (HER2) antigen that is highly expressed on some types of cancer and Barnase*Barstar native bacterial proteins interacted with each other with K 10 M. The approach proposed consists of prelabeling a target tumor with hybrid protein DARPin-Barnase prior to administration of cytotoxic component-loaded liposomes that have Barstar covalently attached to their surface.

DARPin_9-29-Targeted Gold Nanorods Selectively Suppress HER2-Positive Tumor Growth in Mice.

Near-infrared phototherapy has great therapeutic potential for cancer treatment. However, for efficient application, in vivo photothermal agents should demonstrate excellent stability in blood and targeted delivery to pathological tissue. Here, we demonstrated that stable bovine serum albumin-coated gold mini nanorods conjugated to a HER2-specific designed ankyrin repeat protein, DARPin_9-29, selectively accumulate in HER2-positive xenograft tumors in mice and lead to a strong reduction in the tumor size when being illuminated with near-infrared light.

Natural and Designed Toxins for Precise Therapy: Modern Approaches in Experimental Oncology.

Cancer cells frequently overexpress specific surface receptors providing tumor growth and survival which can be used for precise therapy. Targeting cancer cell receptors with protein toxins is an attractive approach widely used in contemporary experimental oncology and preclinical studies. Methods of targeted delivery of toxins to cancer cells, different drug carriers based on nanosized materials (liposomes, nanoparticles, polymers), the most promising designed light-activated toxins, as well as mechanisms of the cytotoxic action of the main natural toxins used in modern experimental oncology, are discussed in this review.

Near-Infrared Activated Cyanine Dyes As Agents for Photothermal Therapy and Diagnosis of Tumors.

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 (700-900 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.

Dual Targeting of Cancer Cells with DARPin-Based Toxins for Overcoming Tumor Escape.

We report here a combined anti-cancer therapy directed toward HER2 and EpCAM, common tumor-associated antigens of breast cancer cells. The combined therapeutic effect is achieved owing to two highly toxic proteins-a low immunogenic variant of exotoxin A and ribonuclease Barnase from . The delivery of toxins to cancer cells was carried out by targeting designed ankyrin repeat proteins (DARPins).

Dual Regioselective Targeting the Same Receptor in Nanoparticle-Mediated Combination Immuno/Chemotherapy for Enhanced Image-Guided Cancer Treatment.

When combined with immunotherapy, image-guided targeted delivery of chemotherapeutic agents is a promising direction for combination cancer theranostics, but this approach has so far produced only limited success due to a lack of molecular targets on the cell surface and low therapeutic index of conventional chemotherapy drugs. Here, we demonstrate a synergistic strategy of combination immuno/chemotherapy in conditions of dual regioselective targeting, implying vectoring of two distinct binding sites of a single oncomarker (here, HER2) with theranostic compounds having a different mechanism of action. We use: (i) PLGA nanoformulation, loaded with an imaging diagnostic fluorescent dye (Nile Red) and a chemotherapeutic drug (doxorubicin), and functionalized with affibody Z (8 kDa); (ii) bifunctional genetically engineered DARP-LoPE (42 kDa) immunotoxin comprising of a low-immunogenic modification of therapeutic exotoxin A (LoPE) and a scaffold targeting protein, DARPin9.

Death Mechanism of Breast Adenocarcinoma Cells Caused by BRET-Induced Cytotoxicity of miniSOG Depends on the Intracellular Localization of the NanoLuc-miniSOG Fusion Protein.

Photodynamic therapy (PDT) is widely used in clinical practice to influence neoplasms in the presence of a photosensitizer, oxygen, and light source. The main problem of PDT of deep tumors is the problem of delivering excitation light (without lost of its intensity) inside the body. An alternative to the external light sources can be the internal light sources based on luciferase-substrate bioluminescent systems.

Phototoxicity of flavoprotein miniSOG induced by bioluminescence resonance energy transfer in genetically encoded system NanoLuc-miniSOG is comparable with its LED-excited phototoxicity.

Photodynamic therapy (PDT) is a clinical, minimally invasive method for destroying cancer cells in the presence of a photosensitizer, oxygen, and a light source. The main obstacle for the PDT treatment of deep tumors is a strong reduction of the excitation light intensity as a result of its refraction, reflection, and absorption by biological tissues. Internal light sources based on bioluminescence resonance energy transfer can be a solution of this problem.

[Bifunctional Toxin DARP-LoPE Based on the HER2-Specific Innovative Module of a Non-Immunoglobulin Scaffold as a Promising Agent for Theranostics].

We have generated and characterized HER2-specific targeted toxin based on the low-immunogenic variant of Pseudomonas exotoxin A (LoPE), in which most of the human immunodominant B-cell epitopes have been inactivated. Nonimmunoglobulin DARPin-based HER2-specific protein was used as a targeting module for toxin delivery to the cellular target. Using confocal microscopy, it has been found that both domains in this hybrid toxin retained their functionality, i.

Flavoprotein miniSOG BRET-induced cytotoxicity depends on its intracellular localization.

It is proposed to use the bioluminescent resonance energy transfer to solve the problem of creating the internal light sources in photodynamic therapy of cancer. Energy donor in the developed system is the oxidized form of the luciferase NanoLuc substrate furimamide, and acceptor is the phototoxic fluorescent protein miniSOG. It is shown that, in the proposed system, the photoinduced cytotoxicity of flavoprotein miniSOG in vitro depends on the intracellular localization, and the cytotoxic effect is 48% for the cytoplasmic localization of the fusion protein, 65% for the mitochondrial localization, and 69% for the membrane localization.

Flavoprotein miniSOG Cytotoxisity Can Be Induced By Bioluminescence Resonance Energy Transfer.

In this study, we investigated the possibility of phototoxic flavoprotein miniSOG (photosensitizer) excitation in cancer cells by bioluminescence occurring when luciferase NanoLuc oxidizes its substrate, furimazine. We have shown that the phototoxic flavoprotein miniSOG expressed in eukaryotic cells in fusion with NanoLuc luciferase is activated in the presence of its substrate, furimazine. Upon such condition, miniSOG possesses photoinduced cytotoxicity and causes a 48% cell death level in a stably transfected cell line.

Acipensins - Novel Antimicrobial Peptides from Leukocytes of the Russian Sturgeon Acipenser gueldenstaedtii.

Antimicrobial peptides (AMPs) play an important role in the innate defense mechanisms in humans and animals. We have isolated and studied a set of antimicrobial peptides from leukocytes of the Russian sturgeon Acipenser gueldenstaedtii belonging to a subclass of chondrosteans, an ancient group of bony fish. Structural analysis of the isolated peptides, designated as acipensins (Ac), revealed in leukocytes of the Russian sturgeon six novel peptides with molecular masses of 5336.

Characteristics of new monomolecular chimeric T-cell receptors to carcinoembryonic antigen.

We described two original genetic constructs encoding chimeric monomolecular T-cell receptors, where the effector T-cell receptor fragment was linked with the antigen-recognizing part consisting of two variable fragments of two different antibodies to carcinoembryonic antigen. Following transfection, these receptors were expressed on the cell surface and bound carcinoembryonic antigen. Human peripheral blood lymphocytes transfected with the above constructs demonstrated high cytotoxic activity against HCT116 cells expressing carcinoembryonic antigen.

[The status of nucleolus organizing regions in hybrids of pluripotent and somatic mouse cells cultured under different conditions].

In the present work we examined the status of nucleolus organizing regions of mitotic chromosomes (NOR) in hybrid cells obtained by fusion of the mouse teratocarcinoma cells PCC4aza1 and adult mouse spleenocytes upon cultivation of hybrid cells under different conditions. We have shown that extended cultivation of hybrid cells in medium supplemented with HAT (hypoxanthine, aminopterin, thymidine) promotes the maintenance of NO-chromosomes, whereas under nonselective conditions elimination of NO-chromosome occurs. In nonselective medium the number of active, i.