Antibacterial Activity of Various Morphologies of Films Based on Guanidine Derivatives of Pillar[5]arene: Influence of the Nature of One Substitute on Self-assembly.

The progress of the pillar[5]arene chemistry allowed us to set out a new concept on application of the supramolecular assemblies to create antimicrobial films with variable surface morphologies and biological activities. Antibacterial films were derived from the substituted pillar[5]arenes containing nine pharmacophoric guanidine fragments and one thioalkyl substituent. Changing the only thioalkyl fragment in the macrocycle structure made it possible to control the biological activity of the resulting antibacterial coating. Pretreatment of the surface with aqueous solution of the amphiphilic pillar[5]arenes reduced the biofilm thickness by 56 ± 10% of Gram-positive Staphylococcus aureus in the case of the pillar[5]arene containing a thiooctyl fragment and by 52 ± 7% for the biofilm of Gram-negative Klebsiella pneumoniae in the case of pillar[5]arene containing a thiooctadecyl fragment. Meanwhile, the cytotoxicity of the synthesized macrocycles was examined at a concentration of 50 µg/mL, which was significantly lower than that of bis-guanidine-based antimicrobial preparations.

UCNP-based Photoluminescent Nanomedicines for Targeted Imaging and Theranostics of Cancer.

Theranostic approach is currently among the fastest growing trends in cancer treatment. It implies the creation of multifunctional agents for simultaneous precise diagnosis and targeted impact on tumor cells. A new type of theranostic complexes was created based on NaYF4: Yb,Tm upconversion nanoparticles coated with polyethylene glycol and functionalized with the HER2-specific recombinant targeted toxin DARPin-LoPE. The obtained agents bind to HER2-overexpressing human breast adenocarcinoma cells and demonstrate selective cytotoxicity against this type of cancer cells. Using fluorescent human breast adenocarcinoma xenograft models, the possibility of intravital visualization of the UCNP-based complexes biodistribution and accumulation in tumor was demonstrated.

HER2-Specific Targeted Toxin DARPin-LoPE: Immunogenicity and Antitumor Effect on Intraperitoneal Ovarian Cancer Xenograft Model.

High immunogenicity and systemic toxicity are the main obstacles limiting the clinical use of the therapeutic agents based on Pseudomonas aeruginosa exotoxin A. In this work, we studied the immunogenicity, general toxicity and antitumor effect of the targeted toxin DARPin-LoPE composed of HER2-specific DARPin and a low immunogenic exotoxin A fragment lacking immunodominant human B lymphocyte epitopes. The targeted toxin has been shown to effectively inhibit the growth of HER2-positive human ovarian carcinoma xenografts, while exhibiting low non-specific toxicity and side effects, such as vascular leak syndrome and liver tissue degradation, as well as low immunogenicity, as was shown by specific antibody titer. This represents prospects for its use as an agent for targeted therapy of HER2-positive tumors.

Targeted Delivery to Tumors: Multidirectional Strategies to Improve Treatment Efficiency.

Malignant tumors are characterized by structural and molecular peculiarities providing a possibility to directionally deliver antitumor drugs with minimal impact on healthy tissues and reduced side effects. Newly formed blood vessels in malignant lesions exhibit chaotic growth, disordered structure, irregular shape and diameter, protrusions, and blind ends, resulting in immature vasculature; the newly formed lymphatic vessels also have aberrant structure. Structural features of the tumor vasculature determine relatively easy penetration of large molecules as well as nanometer-sized particles through a blood⁻tissue barrier and their accumulation in a tumor tissue. Also, malignant cells have altered molecular profile due to significant changes in tumor cell metabolism at every level from the genome to metabolome. Recently, the tumor interaction with cells of immune system becomes the focus of particular attention, that among others findings resulted in extensive study of cells with preferential tropism to tumor. In this review we summarize the information on the diversity of currently existing approaches to targeted drug delivery to tumor, including (i) passive targeting based on the specific features of tumor vasculature, (ii) active targeting which implies a specific binding of the antitumor agent with its molecular target, and (iii) cell-mediated tumor targeting.

3D in vitro models of tumors expressing EGFR family receptors: a potent tool for studying receptor biology and targeted drug development.

Carcinomas overexpressing EGFR family receptors are of high clinical importance, because the receptors have prognostic value and are used as molecular targets for anticancer therapy. Insufficient drug efficacy necessitates further in-depth research of the receptor biology and improvement in preclinical stages of drug evaluation. Here, we review the currently used advanced 3D in vitro models of tumors, including tumor spheroids, models in natural and synthetic matrices, tumor organoids and microfluidic-based models, as a potent tool for studying EGFR biology and targeted drug development. We are especially focused on factors that affect the biology of tumor cells, causing modification in the expression and basic phosphorylation of the receptors, crosstalk with other signaling pathways and switch between downstream cascades, resulting ultimately in the resistance to antitumor agents.

Proteinases from Bacillus intermedius secreted in the late stages of sporulation.

BACKGROUND: Proteinases are widely used in various fields of medicine, such as the treatment of burns, purulent wounds, or decubitus ulcers. On the basis of new microbial proteinases produced by nonpathogenic organisms, a new generation of medical preparations can be developed. Representatives of the Bacillus genera are nonpathogenic and are suitable for producing various proteases in large quantities. B. intermedius is shown to produce a set of alkaline proteases at the early and late stationary phase of growth. MATERIAL/METHODS: The activity of alkaline proteinases was determined using synthetic chromogenous substrates Z-Glu-pNA and Z-Ala-Ala-Leu-pNA. To determine beta-galactosidase activity, 2-nitro-beta-D-galactopyranosid was used. Spores were calculated by phase-contrast microscopy. RESULTS: During the late stages of sporulation B. intermedius 3-19 cells were shown to secrete two proteinases into the medium: glutamyl endopeptidase, with maximum activity at 40 hours of growth, and subtilisin, with maximum activity at 44 hours of growth. Evidence for the secretion of these enzymes into the medium was provided by measuring beta-galactosidase activity. CONCLUSIONS: Our results show that proteinases from B. intermedius (glutamyl endopeptidase 2 and subtilisin 2) in the late stationary phase of growth are secreted enzymes. This suggests that these enzymes play a role in sporulation.