Differential Immunomodulatory Activities of Schiff Base Complexes Depending on their Metal Conjugation

Electrospun nanofiber mats caged the mammalian macrophages on their surfaces and prevented their inflammatory responses independent of the fiber diameter

Poly-ε-caprolactone (PCL) has been widely used as biocompatible materials in tissue engineering. They have been used in mammalian cell proliferation to polarization and differentiation. Their modified versions had regulatory activities on mammalian macrophages in vitro. There are also studies suggesting different nanofiber diameters might alter the biological activities of these materials. Based on these cues, we examined the inflammatory activities and adherence properties of mammalian macrophages on electrospun PCL nanofibrous scaffolds formed with PCL having different nanofiber diameters. Our results suggest that macrophages could easily attach and get dispersed on the scaffolds. Macrophages lost their inflammatory cytokine TNF and IL6 production capacity in the presence of LPS when they were incubated on nanofibers. These effects were independent of the mean fiber diameters. Overall, the scaffolds have potential to be used as biocompatible materials to suppress excessive inflammatory reactions during tissue and organ transplantation by caging and suppressing the inflammatory cells.

Photodynamic anti-inflammatory activity of meso‑aryl substituted porphyrin derivative on mammalian macrophages

BACKGROUND

Our group focused on a meso‑aryl substituted porphyrin molecule for its photodynamic anti-inflammatory activities on the mammalian macrophages.

MATERIALS AND METHODS

The porphyrine derivative previously synthesized in this study was synthesized and characterized by 1H NMR. We then examined their immunomodulatory activities based on the changes in the pro-inflammatory cytokine production levels after LPS stimulation in dark and light activated conditions.

RESULTS

Our results suggest that porphyrin derivative had anti-inflammatory photodynamic activity in vitro at subtoxic concentrations. Our study aims to pave a way for anti-inflammatory photodynamic therapy application in the inflammatory and autoimmune disorders. Most of the studies either focus on photodynamic cytotoxicity of the porphyrin derivatives to suppress the inflammation or porphyrin derivatives' anti-inflammatory activity without the photodynamic activation.

CONCLUSION

Our future studies will focus on the generation and in vitro as well as in vivo characterization of the porphyrin derivatives with anti-inflammatory photodynamic therapy applications. In this way, novel drug candidates that would have lower side effects can be generated for the patients.

An Insight into the Effect of Schiff Base and their d and f Block Metal Complexes on Various Cancer Cell Lines as Anticancer Agents: A Review

Over the last few decades, an alarming rise in the percentage of individuals with cancer and those with multi-resistant illnesses has forced researchers to explore possibilities for novel therapeutic approaches. Numerous medications currently exist to treat various disorders, and the development of small molecules as anticancer agents has considerable potential. However, the widespread prevalence of resistance to multiple drugs in cancer indicates that it is necessary to discover novel and promising compounds with ideal characteristics that could overcome the multidrug resistance issue. The utilisation of metallo-drugs has served as a productive anticancer chemotherapeutic method, and this approach may be implemented for combating multi-resistant tumours more successfully. Schiff bases have been receiving a lot of attention as a group of compounds due to their adaptable metal chelating abilities, innate biologic properties, and versatility to tweak the structure to optimise it for a specific biological purpose. The biological relevance of Schiff base and related complexes, notably their anticancer effects, has increased in their popularity as bio-inorganic chemistry has progressed. As a result of learning about Schiff bases antitumor efficacy against multiple cancer cell lines and their complexes, researchers are motivated to develop novel, side-effect-free anticancer treatments. According to study reports from the past ten years, we are still seeking a powerful anticancer contender. This study highlights the potential of Schiff bases, a broad class of chemical molecules, as potent anticancer agents. In combination with other anticancer strategies, they enhance the efficacy of treatment by elevating the cytotoxicity of chemotherapy, surmounting drug resistance, and promoting targeted therapy. Schiff bases also cause cancer cell DNA repair, improve immunotherapy, prevent angiogenesis, cause apoptosis, and lessen the side effects of chemotherapy. The present review explores the development of potential Schiff base and their d and f block metal complexes as anticancer agents against various cancer cell lines.

Assessment of synergism between enzyme inhibition of Cu/Zn-SOD and antimicrobial photodynamic therapy in suspension and E. coli biofilm

BACKGROUND

Antimicrobial Photodynamic Therapy (aPDT) is a treatment based on the interaction between a photosensitizer (PS), oxygen and a light source, resulting in the production of reactive oxygen species (ROS). There are two main types of reactions that can be triggered by this interaction: type I reaction, which can result in the production of hydrogen peroxide, superoxide anion and hydroxyl radical, and type II reaction, which is the Photodynamic Reaction, which results in singlet oxygen production. Antioxidant enzymes (e.g., catalase and superoxide dismutase) are agents that help prevent the damage caused by ROS and, consequently, reduce the effectiveness of aPDT. The aim of this study was to evaluate a possible synergism of the combined inhibition therapy of the enzyme Cu/Zn-Superoxide dismutase (SOD) and the methylene blue- and curcumin-mediated aPDT against Escherichia coli ATCC 25922, in suspension and biofilm.

METHODS

Kinetic assay of antimicrobial activity of diethydithiocarbamate (DDC) and Minimum Bactericidal Concentration (MIC) of DDC were performed to evaluate the behavior of the compound on bacterial suspension. Inhibition times of Cu/Zn-SOD, as well as DDC concentration, were evaluated via bacterial susceptibility to combined therapy in suspension and biofilm.

RESULTS

DDC did not present MIC at the evaluated concentrations. The inhibition time and Cu/Zn-SOD concentration with the highest bacterial reductions were 30 minutes and 1.2 μg/mL, respectively. Synergism occurred between DDC and MB-mediated aPDT, but not with CUR-mediated aPDT.

CONCLUSIONS

The synergism between Cu/Zn-SOD inhibition and aPDT has been confirmed, opening up a new field of study full of possibilities.

Water-Based Synthesis of Copper Chalcogenide Structures and Their Photodynamic Immunomodulatory Activities on Mammalian Macrophages

Generation of novel and versatile immunomodulatory agents that could suppress excessive inflammation has been crucial to fight against chronic inflammatory and autoimmune disorders. Immunomodulatory agents regulate the function of immune system cells to manage their activities. Current therapy regimens for the inflammatory and autoimmune disorders rely on immunomodulatory drug molecules but they are also associated with unwanted and severe side effects. In order to prevent the side effects associated with drug molecules, the field should generate novel immunomodulatory drug candidates and further test them. Moreover, the generation of photodynamic immunomodulatory molecules would also decrease possible side effects. Photodynamic activation enables specific and localized activation of the active ingredients upon exposure to a certain wavelength of light. In our study, we generated copper-based chalcogenide structures in gel and nanoparticle form by using a water-based method so that they are more biocompatible.After their chemical characterization, they were tested on mammalian macrophages in vitro. Our results suggest that these molecules were anti-inflammatory in dark conditions and their anti-inflammatory potentials significantly increased upon xenon light treatment. We are presenting novel photodynamic immunomodulatory agents that can be used to suppress excessive inflammation in disease conditions that have been associated with excessive inflammation.

Novel benzoylthiourea derivatives had differential anti-inflammatory photodynamic therapy potentials on in vitro stimulated mammalian macrophages

Novel benzoylthioureas, N-((5-chloropyridin-2yl)carbamothioyl)benzamide, (HL¹), N-((2-chloropyridin-3yl)carbamothioyl)benzamide, (HL²), N-((5-bromopyridin-2yl)carbamothioyl)benzamide, (HL³) and N-(Naphthalene-1-yl(phenyl)carbamothioyl)benzamide, (HL⁴), were synthesized. Their characterizations were made by FT-IR,¹H NMR and ¹³C NMR spectrophotometric analysis. Single crystal X-ray diffraction measurements were conducted to determine the crystal structure of HL¹ and HL⁴.  The HL¹ crystallization conditions are: in the monoclinic crystal system with P2₁/c space group, Z = 2, a = 8.118(2) Å, b = 12.056(3) Å, c = 13.753(4) Å. HL⁴crystallization conditions are: in the orthorhombic crystal system with Pbca space group, Z = 8, a = 19.597(9) Å, b = 8.270(4) Å, c = 24.299(11) Å. Investigation of photodynamic and antiinflamatory effects of these compounds revealed that they are potent adducts. Using these derivatives, mammalian macrophages were stimulated with LPS to test their anti-inflammatory activity. Based on pro-inflammatory cytokine production levels, the photodynamic anti-inflammatory activity of these adducts were found to differ. Our results showedthat benzoylthioureas can be used as potential photodynamic therapy agents to suppress the excessive inflammatory reactions encountered in autoimmune and inflammatory disorders.

Antimicrobial Photodynamic Therapy: Latest Developments with a Focus on Combinatory Strategies

Antimicrobial photodynamic therapy (aPDT) has become a fundamental tool in modern therapeutics, notably due to the expanding versatility of photosensitizers (PSs) and the numerous possibilities to combine aPDT with other antimicrobial treatments to combat localized infections. After revisiting the basic principles of aPDT, this review first highlights the current state of the art of curative or preventive aPDT applications with relevant clinical trials. In addition, the most recent developments in photochemistry and photophysics as well as advanced carrier systems in the context of aPDT are provided, with a focus on the latest generations of efficient and versatile PSs and the progress towards hybrid-multicomponent systems. In particular, deeper insight into combinatory aPDT approaches is afforded, involving non-radiative or other light-based modalities. Selected aPDT perspectives are outlined, pointing out new strategies to target and treat microorganisms. Finally, the review works out the evolution of the conceptually simple PDT methodology towards a much more sophisticated, integrated, and innovative technology as an important element of potent antimicrobial strategies.

From solid state to in vitro anticancer activity of copper(II) compounds with electronically-modulated NNO Schiff base ligands

The copper(ii) complexes of general formula [Cu(GL)(Cl)] (1-3, G = OMe, H and NO2, respectively), bearing tridentate Schiff base ligands (GL-) and a chloride as a fourth labile one, are here reported. The Schiff bases derive from the monocondensation of ethylenediamine and substituted salicylaldehyde, where the electronic properties are modulated by the releasing or withdrawing power of the G group. The compounds were structurally characterized through single crystal Synchrotron X-ray diffraction experiments in the solid state, revealing that 1 (OMe) and 2 (H) adopt a dimeric assembly [Cu(μ-Cl)(GL)]2 through apical interaction of the chloride ions of two monomeric units, while 3 embraces a 1D polymeric chain structure [Cu(μ-Cl)(NO2L)]n with a similar bridging fashion, all supported by extended intramolecular or intrachain hydrogen bonds. The redox properties of the complexes were also studied by cyclic voltammetry with no marked effect of the substituent on the potential of the CuII/CuI redox system. UV/Vis spectroscopic studies in mimicked physiological conditions highlighted the intactness and stability of the coordinated NNO tridentate ligand in 1-3 and the lability of the coordinated chloride ion with the formation of the aquo-complexes [Cu(GL)(H2O)]+ in aqueous solution, as confirmed by conductance measurements with a 1 : 1 electrolyte molar conductivity. In vitro tests on cell viability were conducted on malignant cell lines typical for their poor prognosis and curability, revealing time-dependent and differential cytotoxicity given by the substituent G. All compounds were capable of formation of intracellular reactive oxygen species and DNA intercalation, acting as nuclease and producing double-strand DNA breaks. This is especially effective for 3 (NO2), which revealed the highest anticancer activity against malignant triple-negative breast cancer MDA-MB-231 cells, with a two-to-four-fold cytotoxicity enhancement with respect to 1 (OMe) and 2 (H), and, most important, substantial differentiation of cytotoxicity with respect to healthy endothelial HUVEC cell line.

Pt(II) and Au(III) complexes containing Schiff-base ligands: A promising source for antitumor treatment

The effective application of cisplatin in the clinic as an antitumor treatment has stimulated widespread interest in inorganic metal drugs. In particular, complexes containing the transition metals platinum and gold have attracted considerable attention due to their antitumor effects. The Pt(II) and Au(III) Schiff-base complexes are potential antitumor agents because of their remarkable biological activities and good stability, lipophilicity, and electroluminescent properties. These complexes act via various antitumor mechanisms that are unlike those of the classic platinum drugs, providing a feasible solution for improving the serious side effects caused by metal chemotherapy. In this review, promising antitumor agents based on Pt(II) and Au(III) complexes containing Schiff-base ligands, and their biological targets, including G-quadruplex DNA and thioredoxin reductase, are comprehensively summarized.

Immunoactive photosensitizers had photodynamic immunostimulatory and immunomodulatory effects on mammalian macrophages

Photodynamic compounds have great potential in biological applications. Their controlled and localized activation with specific wavelength of light provides opportunities to potentially evade the side effects of today's cancer therapies. Biologically compatible photosensitizers can be used in therapy against cancer, infections as well as inflammatory and immune disorders. In this study, we examined chlorophyll derivatives for anti-microbial, immunostimulatory and immunomodulatory activities. Under dark conditions, these chlorophyll derivatives had strong anti-microbial activities on gram positive S.aureus and gram negative E.coli. Photo activation of the chlorophyll derivatives did not alter their anti-microbial activities on gram negative or gram positive bacteria. In order to examine how these anti-microbial chlorophyll derivatives might effect immune reaction of macrophages, they were tested on mammalian macrophages. They had immunostimulatory activities on them in the dark conditions since they led to increased TNF and IL6 cytokine production even in the absence of stimulants lipopolysaccharide (LPS) and lipoteichoic acid (LTA). Photo-activation of the compounds led to decrease in pro-inflammatory cytokines, TNF and IL6, production by LPS or LTA activated macrophages. Therefore, these molecules can be used to regulate the immune response in the patients with bacterial infection while leading to death of bacteria. Light induced activation of the compounds could enable localized and controlled activation of their anti-inflammatory effects.

DNA-damage and cell cycle arrest initiated anti-cancer potency of super tiny carbon dots on MCF7 cell line

While carbon-based materials have spearheaded numerous breakthroughs in biomedicine, they also have procreated many logical concerns on their overall toxicity. Carbon dots (CDs) as a respectively new member have been extensively explored in nucleus directed delivery and bioimaging due to their intrinsic fluorescence properties coupled with their small size and surface properties. Although various in vitro/in vivo studies have shown that CDs are mostly biocompatible, sufficient information is lacking regarding genotoxicity of them and underlying mechanisms. This study aims to analyze the real-time cytotoxicity of super tiny CDs (2.05 ± 0.22 nm) on human breast cancer cells (MCF7) and human primary dermal fibroblast cell cultures (HDFa) by xCELLigence analysis system for further evaluating their genotoxicity and clastogenicity to evaluate the anti-tumor potential of CDs on breast adenocarcinoma. As combined with flow cytometry studies, comet assay and cytokinesis-block micronucleus assay suggest that the CDs can penetrate to the cell nuclei, interact with the genetic material, and explode DNA damage and G0/G1 phase arrest in cancer cells even at very low concentrations (0.025 ppm) which provide a strong foundation for the design of potentially promising CD-based functional nanomaterials for DNA-damage induced treatment in cancer therapy.

Ruthenium Bipyridyl Dithiocyanate Complex Exerted Adjuvant Activity on the Activated Mammalian Macrophages in vitro

A cell's function can be regulated through its mechanism, and there has been a growing body of literature on how immune cells' metabolism shapes its overall immune response. Manipulation of the cells metabolic activity through a biocompatible material would present new venues to the field of medicine. These agents are known as immunomodulatory and immunostimulatory reagents. They can either stimulate the immune response in a disease case where the immune response is lacking the strength or they can determine the nature and strength of the immune response as an immunomodulator according to our needs to cope with certain disorders. In our recent studies, we have been examining different kinds of materials on the macrophages in order to delineate their immunostimulatory or immunomodulatory potentials. Ruthenium-based materials have gathered our attention due to their ability to get involved into the electron mobility processes in the solar cells. In line with our expectations, probably by interfering the electron transport processes of the macrophages, ruthenium bipyridyl dithiocyanate complex had a stark immunomodulatory function on the LPS-activated mammalian macrophages in vitro. Our results support that it can be utilized as an adjuvant in the new generation vaccines.

Differential effects of aminochlorin derivatives on the phagocytic and inflammatory potentials of mammalian macrophages

Chlorin derivatives have been known for their biological activities. Especially due to their advanced electron transfer capacity they have been used as photodynamic therapy agent both at clinical and laboratory scales. Photodynamic therapy (PDT) against cancer or an infectious disease aims the development of less side effect on the patient since the activation of the inert drug molecule will start only after the light treatment. In order to increase our library of photodynamic therapy agents, we generated a set of chlorin derivatives and tested their PDT potential on the immune system cells; macrophages. Macrophages are known for their primary role as an inflammatory cell type that have been found in the inflamed tissues of the patients with autoimmune and inflammatory disorders as well as in the tumor environment as tumor associated macrophages. Our derivatives had anti-inflammatory PDT potential in the presence of a danger mimic but they lacked immunostimulatory effect. Moreover, these cells' ability to eliminate an infectious agent or present the danger molecules to the other immune cells were tested by phagocytosis assay in the presence of our compounds. Chlorin derivatives were able to differentially regulate the phagocytic activity of the mammalian macrophages.