Light-Responsive Pt(IV) Prodrugs with Controlled Photoactivation and Low Dark Toxicity.

Light-induced release of cisplatin from Pt(IV) prodrugs represents a promising approach for precise control over the antiproliferative activity of Pt-based chemotherapeutic drugs. This method has the potential to overcome crucial drawbacks of conventional cisplatin therapy, such as high general toxicity toward healthy organs and tissues. Herein, we report two Pt(IV) prodrugs with BODIPY-based photoactive ligands Pt-1 and Pt-2, which were designed using carbamate and triazole linkers, respectively. Both prodrugs demonstrated the ability to release cisplatin under blue light irradiation without the requirement of an external reducing agent. Dicarboxylated Pt-2 prodrug turned out to be more stable in the dark and more sensitive to light than its monocarbamate Pt-1 counterpart; these observations were explained using DFT calculations. The investigation of the photoreduction mechanism of Pt-1 and Pt-2 prodrugs using DFT modeling and ΔG0 PET estimation suggests that the photoinduced electron transfer from the singlet excited state of the BODIPY axial ligand to the Pt(IV) center is the key step in the light-induced release of cisplatin from the complexes. Cytotoxicity studies demonstrated that both prodrugs were nontoxic in the dark and toxic to MCF-7 cells under low-dose irradiation with blue light, and the observed effect was solely due to the cisplatin release from the Pt(IV) prodrugs. Our research presents an elegant synthetic approach to light-activated Pt(IV) prodrugs and presents findings that may contribute to the future rational design of photoactivatable Pt(IV) prodrugs.

Metal and Metal Oxides Nanoparticles and Nanosystems in Anticancer and Antiviral Theragnostic Agents.

The development of antiviral treatment and anticancer theragnostic agents in recent decades has been associated with nanotechnologies, and primarily with inorganic nanoparticles (INPs) of metal and metal oxides. The large specific surface area and its high activity make it easy to functionalize INPs with various coatings (to increase their stability and reduce toxicity), specific agents (allowing retention of INPs in the affected organ or tissue), and drug molecules (for antitumor and antiviral therapy). The ability of magnetic nanoparticles (MNPs) of iron oxides and ferrites to enhance proton relaxation in specific tissues and serve as magnetic resonance imaging contrast agents is one of the most promising applications of nanomedicine. Activation of MNPs during hyperthermia by an external alternating magnetic field is a promising method for targeted cancer therapy. As therapeutic tools, INPs are promising carriers for targeted delivery of pharmaceuticals (either anticancer or antiviral) via magnetic drug targeting (in case of MNPs), passive or active (by attaching high affinity ligands) targeting. The plasmonic properties of Au nanoparticles (NPs) and their application for plasmonic photothermal and photodynamic therapies have been extensively explored recently in tumor treatment. The Ag NPs alone and in combination with antiviral medicines reveal new possibilities in antiviral therapy. The prospects and possibilities of INPs in relation to magnetic hyperthermia, plasmonic photothermal and photodynamic therapies, magnetic resonance imaging, targeted delivery in the framework of antitumor theragnostic and antiviral therapy are presented in this review.

Copper coordination compounds with (5Z,5Z')-2,2'-(alkane-α,ω-diyldiselenyl)-bis-5-(2-pyridylmethylene)-3,5-dihydro-4H-imidazol-4-ones. Comparison with sulfur analogue.

A series of new organic ligands (5Z,5Z')-2,2'-(alkane-α,ω-diyldiselenyl)-bis-5-(2-pyridylmethylene)-3,5-dihydro-4H-imidazol-4-ones (L) consisting of two 5-(2-pyridylmethylene)-3,5-dihydro-4H-imidazol-4-one units linked with polymethylene chains of various lengths (n = 2-10, where n is the number of CH2 units) have been synthesized. The reactions of these ligands with CuCl2·2H2O and CuClO4·6H2O gave Cu2+ or Cu1+ containing mono- and binuclear complexes with Cu2LCl x (x = 2-4) or CuL(ClO4) y (y = 1, 2) composition. It was shown that the agents reducing Cu2+ to Cu1+ in the course of complex formation can be both a ligand and an organic solvent in which the reaction is carried out. This fundamentally distinguishes the selenium-containing ligands L from their previously described sulfur analogs, which by themselves are not capable of reducing Cu2+ during complexation under the same conditions. A higher cytotoxicity and reasonable selectivity to cancer cell lines for synthesized complexes of selenium-containing ligands was shown; unlike sulfur analogs, ligands L themselves demonstrate a high cytotoxicity, comparable in some cases to the toxicity of copper-containing complexes.

The Role of D2-like Dopaminergic Receptor in Dopamine-mediated Modulation of Th17-cells in Multiple Sclerosis.

BACKGROUND: Dopamine is one of the main mediators capable regulate the neuroimmune interaction and is involved in multiple sclerosis (MS) pathogenesis. OBJECTIVE: The aim of this study was to clarify the role of dopamine and its receptors in modulation of Th17-cells in MS. METHODS: 34 relapsing-remitting MS patients and 23 healthy subjects were examined. To assess the effect of dopamine on Th17-cells, CD4+ T-cells were cultured in the presence of dopamine and antagonist or agonist of D1- or D2-like dopaminergic receptors and stimulated with anti-CD3/CD28- microbeads. The levels of cytokines in supernatants were assessed by ELISA. RESULTS: Production of interleukin-17 (IL-17), interferon-γ (IFN-γ), granulocyte-colony stimulating factor (GM-CSF), and IL-21 by CD4+ T-cells as well as dopamine were comparable between the groups. Dopamine suppressed cytokine secretion by activated СD4+ T-cells in both groups. Blockade of D1-like dopaminergic receptor with a specific antagonist SCH23390 did not affect dopaminemediated cytokine suppression. In contrast, blockade of D2-like dopaminergic receptor by sulpiride decreased dopamine's inhibitory effect on IL-17 secretion in both groups and GM-CSF and IL-21 production in MS patients. Blockade of D1-like dopaminergic receptor directly inhibited IL-17, IFN- γ, GM-CSF in both groups and IL-21 production in healthy subjects, while blockade of D2-like dopaminergic receptor had no effect on cytokine secretion. Finally, activation of D2-like dopaminergic receptor with a specific agonist quinpirole decreased cytokine production in both groups. CONCLUSION: These data suggest an inhibitory role of dopamine on Th17-cells in MS, which could be mediated by the activation of the D2-like dopaminergic receptor.

Novel Copper-Containing Cytotoxic Agents Based on 2-Thioxoimidazolones.

A series of 73 ligands and 73 of their Cu+2 and Cu+1 copper complexes with different geometries, oxidation states of the metal, and redox activities were synthesized and characterized. The aim of the study was to establish the structure-activity relationship within a series of analogues with different substituents at the N(3) position, which govern the redox potentials of the Cu+2/Cu+1 redox couples, ROS generation ability, and intracellular accumulation. Possible cytotoxicity mechanisms, such as DNA damage, DNA intercalation, telomerase inhibition, and apoptosis induction, have been investigated. ROS formation in MCF-7 cells and three-dimensional (3D) spheroids was proven using the Pt-nanoelectrode. Drug accumulation and ROS formation at 40-60 µm spheroid depths were found to be the key factors for the drug efficacy in the 3D tumor model, governed by the Cu+2/Cu+1 redox potential. A nontoxic in vivo single-dose evaluation for two binuclear mixed-valence Cu+1/Cu+2 redox-active coordination compounds, 72k and 61k, was conducted.

Influence of succinylation of a wide-pore albumin cryogels on their properties, structure, biodegradability, and release dynamics of dioxidine loaded in such spongy carriers.

The goal of this study was to reveal how the chemical modification, succinylation in this case, of the wide-pore serum-albumin-based cryogels affects on their osmotic characteristics (swelling extent), biodegradability and ability to be loaded with the bactericide substance - dioxidine, as well as on its release. The cryogels were prepared via the cryogenic processing (freezing - frozen storage - thawing) of aqueous solutions containing bovine serum albumin (50 g/L), denaturant (urea or guanidine hydrochloride, 1.0 mol/L) and reductant (cysteine, 0.01 mol/L). Freezing/frozen storage temperatures were either -15, or -20, or -25 °C. After defrosting, spongy cryogels were obtained that possessed the system of interconnected gross pores, whose shape and dimensions were dependent on the freezing temperature and on the type of denaturant introduced in the feed solution. Subsequent succinylation of the resultant cryogels caused the growth of the swelling degree of the pore walls of these spongy materials, resulted in strengthening of their resistance against of trypsinolysis and gave rise to an increase in their loading capacity with respect to dioxidine. With that, the microbiological tests showed a higher bactericidal activity of the dioxidine-loaded sponges based on the succinylated albumin cryogels as compared to that of the drug-carriers based on the non-modified protein sponges.

Glycolytic reprogramming of macrophages activated by NOD1 and TLR4 agonists: No association with proinflammatory cytokine production in normoxia.

Upon activation with pathogen-associated molecular patterns, metabolism of macrophages and dendritic cells is shifted from oxidative phosphorylation to aerobic glycolysis, which is considered important for proinflammatory cytokine production. Fragments of bacterial peptidoglycan (muramyl peptides) activate innate immune cells through nucleotide-binding oligomerization domain (NOD) 1 and/or NOD2 receptors. Here, we show that NOD1 and NOD2 agonists induce early glycolytic reprogramming of human monocyte-derived macrophages (MDM), which is similar to that induced by the Toll-like receptor 4 (TLR4) agonist lipopolysaccharide. This glycolytic reprogramming depends on Akt kinases, independent of mTOR complex 1 and is efficiently inhibited by 2-deoxy-d-glucose (2-DG) or by glucose starvation. 2-DG inhibits proinflammatory cytokine production by MDM and monocyte-derived dendritic cells activated by NOD1 or TLR4 agonists, except for tumor necrosis factor production by MDM, which is inhibited initially, but augmented 4 h after addition of agonists and later. However, 2-DG exerts these effects by inducing unfolded protein response rather than by inhibiting glycolysis. By contrast, glucose starvation does not cause unfolded protein response and, in normoxic conditions, only marginally affects proinflammatory cytokine production triggered through NOD1 or TLR4. In hypoxia mimicked by treating MDM with oligomycin (a mitochondrial ATP synthase inhibitor), both 2-DG and glucose starvation strongly suppress tumor necrosis factor and interleukin-6 production and compromise cell viability. In summary, the requirement of glycolytic reprogramming for proinflammatory cytokine production in normoxia is not obvious, and effects of 2-DG on cytokine responses should be interpreted cautiously. In hypoxia, however, glycolysis becomes critical for cytokine production and cell survival.

3-(2-Azidoethyl)oxindoles: Advanced Building Blocks for One-Pot Assembly of Spiro[pyrrolidine-3,3'-oxindoles].

A new synthetic approach to biologically relevant spiro[pyrrolidine-3,3'-oxindoles] was developed on the basis of the cascade transformation of 3-(2-azidoethyl)oxindoles via Staudinger/aza-Wittig/Mannich reactions. The parent azides were readily synthesized through a nucleophilic ring opening of spiro[cyclopropane-1,3'-oxindoles] with the azide ion. A series of new spiro[pyrrolidine-3,3'-oxindoles] with various (het)aryl substituents at the C2 and C5 positions of the pyrrolidine ring were synthesized. In vitro experiments revealed their high cytotoxicity toward LNCaP and PC-3 tumor cell lines.

Simple assembly of polysubstituted pyrazoles and isoxazoles via ring closure-ring opening domino reaction of 3-acyl-4,5-dihydrofurans with hydrazines and hydroxylamine.

A convenient general approach to 2-(pyrazol-4-yl)- and 2-(isoxazol-4-yl)ethanols based on the Brønsted acid-initiated reaction of 3-acyl-4,5-dihydrofurans with hydrazines or hydroxylamine was developed. Further transformation of the alcohol moiety in 2-(pyrazolyl)ethanols affording 2-(pyrazolyl)ethylamine as potent bioactive compounds as well as pyrazole-substituted derivatives of antitumor alkaloid crispine A was elaborated.

A bioinspired route to indanes and cyclopentannulated hetarenes via (3+2)-cyclodimerization of donor-acceptor cyclopropanes.

A novel Lewis acid-catalyzed domino (3+2)-cyclodimerization of 2-arylcyclopropane-1,1-diesters and related stepwise cross-reaction of two different cyclopropanes were developed. These processes provide efficient and highly stereoselective access to polyoxygenated indanes and cyclopentannulated heteroarene derivatives, which display significant cytotoxicity against several lines of cancer cells (IC50 of 10(-6)-10(-5) M) while being non-toxic for normal cells.