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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.

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. The prospects of the combined therapy of tumors based on multimodal nanostructures are also discussed.

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 ZHER2:342 (8 kDa); (ii) bifunctional genetically engineered DARP-LoPE (42 kDa) immunotoxin comprising of a low-immunogenic modification of therapeutic Pseudomonas exotoxin A (LoPE) and a scaffold targeting protein, DARPin9.29 (14 kDa). According to the proposed strategy, the first chemotherapeutic nanoagent is targeted by the affibody to subdomain III and IV of HER2 with 60-fold specificity compared with nontargeted particles, while the second immunotoxin is effectively targeted by DARPin molecule to subdomain I of HER2. We demonstrate that this dual targeting strategy can enhance anticancer therapy of HER2-positive cells with a very strong synergy, which made possible 1000-fold decrease of effective drug concentration in vitro and a significant enhancement of HER2 cancer therapy compared to monotherapy in vivo. Moreover, this therapeutic combination prevented the appearance of secondary tumor nodes. Thus, the suggested synergistic strategy utilizing dual targeting of the same oncomarker could give rise to efficient methods for aggressive tumors treatment.

Barnase is an extracellular ribonuclease secreted by Bacillus amyloliquefaciens 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. Moreover, compared to other dimerization systems, the barnase-barstar module provides the exact one-to-one ratio of the complex components and possesses high stability of each component in a complex and high solubility in aqueous solutions without self-aggregation. The unique properties of barnase and barstar allow the application of this pair for the engineering of different variants of targeted anticancer compounds and cytotoxic supramolecular complexes. Using barnase in suicide gene therapy has also found its niche in anticancer therapy. The application of barnase and barstar in contemporary experimental cancer therapy is reflected in the review.

Simple Summary Breast cancer is one of the main causes of cancer-related death in women all around the world. The disease becomes largely incurable and lethal after metastasis to distant organs. High level of HER2, a tyrosine kinase receptor, is associated with more aggressive clinical behavior and poor prognosis for breast cancer patients. In this paper, we developed a novel nano-biomaterial for selective photothermal therapy of HER2-positive breast cancers. We demonstrate that bovine serum albumin (BSA)-coated mini gold nanorods (GNRs) chemically conjugated with 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. Abstract 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. The results pave the way for the development of novel DARPin-based targeted photothermal therapy of cancer.

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 &ndash, a low immunogenic variant of Pseudomonas aeruginosa exotoxin A and ribonuclease Barnase from Bacillus amyloliquefaciens. The delivery of toxins to cancer cells was carried out by targeting designed ankyrin repeat proteins (DARPins). We have shown that both target agents efficiently accumulate in the tumor. Simultaneous treatment of breast carcinoma-bearing mice with anti-EpCAM fusion toxin based on LoPE and HER2-specific liposomes loaded with Barnase leads to concurrent elimination of primary tumor and metastases. Monotherapy with anti-HER2- or anti-EpCAM-toxins did not produce a comparable effect on metastases. The proposed approach can be considered as a promising strategy for significant improvement of cancer therapy.

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 5336.2 Da, 3803.0 Da, 5173.0 Da, 4777.5 Da, 5449.4 Da, and 2740.2 Da, designated as Ac1–Ac6, respectively. Complete primary structures of all the isolated peptides were determined, and the biological activities of three major components – Ac1, Ac2, and Ac6 – were examined. The peptides Ac1, Ac2, Ac3, Ac4, and Ac5 were found to be the N-terminal acetylated fragments 1–0, 1–5, 1–9, 1–4, and 1–1 of the histone H2A, respectively, while Ac6 was shown to be the 62–5 fragment of the histone H2A. The peptides Ac1 and Ac2 displayed potent antimicrobial activity towards Gram-negative and Gram-positive bacteria (Escherichia coli ML35p, Listeria monocytogenes EGD, MRSA ATCC 33591) and the fungus Candida albicans 820, while Ac6 proved effective only against Gram-negative bacteria. The efficacy of Ac 1 and Ac2 towards the fungus and MRSA was reduced upon an increase in the ionic strength of the solution. Ac1, Ac2, and Ac6, at concentrations close to their minimum inhibitory concentrations, enhanced the permeability of the E.coli ML35p outer membrane to the chromogenic marker, but they did not affect appreciably the permeability of the bacterial inner membrane in comparison with a potent pore-forming peptide, protegrin 1. Ac1, Ac2, and Ac6 revealed no hemolytic activity against human erythrocytes at concentrations of 1 to 40 μM and had no cytotoxic effect (1 to 20 μM) on K-562 and U-937 cells in vitro. Our findings suggest that histone-derived peptides serve as important anti-infective host defense molecules.

Антимикробные пептиды (АМП) являются важнейшими компонентами системы врожденного иммунитета человека и животных. Охарактеризован ряд АМП, выделенных нами из лейкоцитов русского осетра Acipenser gueldenstaedtii - представителя подкласса хрящевых ганоидов, формирующих наиболее древнюю группу костных рыб. Структурный анализ пептидов, названных аципенсинами (Ac), показал, что лейкоциты осетра содержат шесть пептидов с молекулярными массами 5336.2, 3803.0, 5173.0, 4777.5 и 5449.4 и 2740.2 Да, обозначенных Ac1-Ac6 соответственно. Нами определены полные первичные структуры всех выделенных пептидов и исследована биологическая активность трех главных компонентов - Ас1, Ас2 и Ac6. Установлено, что Ас1, Ас2, Ас3, Ас4 и Ас5 представляют собой N-концевые ацетилированные фрагменты 1-50, 1-35, 1-49, 1-44 и 1-51 гистона Н2А соответственно, а Ас6 является фрагментом 62-85 гистона Н2А. Выделенные из лейкоцитов пептиды Ас1 и Ас2 обладают высокой антимикробной активностью в отношении грамотрицательных и грамположительных бактерий ( Escherichia coli ML-35p, Listeria monocytogenes EGD, MRSA ATCC 33591), а также гриба Candida albicans 820. Ас6 активен только в отношении грамотрицательной бактерии. Активность Ac1 и Ас2 в отношении гриба и MRSA снижалась при повышении ионной силы раствора. В концентрациях, близких к минимальным ингибирующим, Ас1, Ас2 и Ас6 увеличивали проницаемость наружной мембраны E. coli ML-35p для хромогенного маркера, но их влияние на проницаемость цитоплазматической мембраны бактерии не было существенным по сравнению с действием мембраноактивного пептида протегрина 1. Все три аципенсина не проявляли гемолитической активности в отношении эритроцитов человека в диапазоне концентраций от 1 до 40 мкМ и не оказывали цитотоксических эффектов на клетки К-562 и U-937 (1-20 мкМ) in vitro . Обнаружение в лейкоцитах осетра антимикробных пептидов, производных гистона Н2А, свидетельствует в пользу предположения о биологически значимой роли гистонов и их фрагментов в обеспечении противоинфекционной защиты.

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.