RASSF1A disrupts the NOTCH signaling axis via SNURF/RNF4-mediated ubiquitination of HES1.

RASSF1A promoter methylation has been correlated with tumor dedifferentiation and aggressive oncogenic behavior. Nevertheless, the underlying mechanism of RASSF1A-dependent tumor dedifferentiation remains elusive. Here, we show that RASSF1A directly uncouples the NOTCH-HES1 axis, a key suppressor of differentiation. Interestingly, the crosstalk of RASSF1A with HES1 occurs independently from the signaling route connecting RASSF1A with the Hippo pathway. At the molecular level, we demonstrate that RASSF1A acts as a scaffold essential for the SUMO-targeted E3 ligase SNURF/RNF4 to target HES1 for degradation. The reciprocal relationship between RASSF1A and HES1 is evident across a wide range of human tumors, highlighting the clinical significance of the identified pathway. We show that HES1 upregulation in a RASSF1A-depleted environment renders cells non-responsive to the downstream effects of γ-secretase inhibitors (GSIs) which restrict signaling at the level of the NOTCH receptor. Taken together, we report a mechanism through which RASSF1A exerts autonomous regulation of the critical Notch effector HES1, thus classifying RASSF1A expression as an integral determinant of the clinical effectiveness of Notch inhibitors.

Serrapeptase impairs biofilm, wall, and phospho-homeostasis of resistant and susceptible Staphylococcus aureus.

Staphylococcus aureus biofilms are implicated in hospital infections due to elevated antibiotic and host immune system resistance. Molecular components of cell wall including amyloid proteins, peptidoglycans (PGs), and lipoteichoic acid (LTA) are crucial for biofilm formation and tolerance of methicillin-resistant S. aureus (MRSA). Significance of alkaline phosphatases (ALPs) for biofilm formation has been recorded. Serrapeptase (SPT), a protease of Serratia marcescens, possesses antimicrobial properties similar or superior to those of many antibiotics. In the present study, SPT anti-biofilm activity was demonstrated against S. aureus (ATCC 25923, methicillin-susceptible strain, methicillin-susceptible S. aureus (MSSA)) and MRSA (ST80), with IC50 values of 0.67 µg/mL and 7.70 µg/mL, respectively. SPT affected bacterial viability, causing a maximum inhibition of - 46% and - 27%, respectively. Decreased PGs content at [SPT] ≥ 0.5 µg/mL and ≥ 8 µg/mL was verified for MSSA and MRSA, respectively. In MSSA, LTA levels decreased significantly (up to - 40%) at lower SPT doses but increased at the highest dose of 2 µg/mL, a counter to spectacularly increased cellular and secreted LTA levels in MRSA. SPT also reduced amyloids of both strains. Additionally, intracellular ALP activity decreased in both MSSA and MRSA (up to - 85% and - 89%, respectively), while extracellular activity increased up to + 482% in MSSA and + 267% in MRSA. Altered levels of DING proteins, which are involved in phosphate metabolism, in SPT-treated bacteria, were also demonstrated here, implying impaired phosphorus homeostasis. The differential alterations in the studied molecular aspects underline the differences between MSSA and MRSA and offer new insights in the treatment of resistant bacterial biofilms. KEY POINTS: • SPT inhibits biofilm formation in methicillin-resistant and methicillin-susceptible S. aureus. • SPT treatment decreases bacterial viability, ALP activity, and cell wall composition. • SPT-treated bacteria present altered levels of phosphate-related DING proteins.

In vitro and in silico evaluation of the serrapeptase effect on biofilm and amyloids of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an emerging threat for hospitalized and cystic fibrosis patients. Biofilm, a microbial community embedded in extracellular polymeric substance, fortifies bacteria against the immune system. In biofilms, the expression of functional amyloids is linked with highly aggregative, multi-resistant strains, and chronic infections. Serrapeptase (SPT), a protease possessing similar or superior anti-microbial properties with many antibiotics, presents anti-amyloid potential. However, studies on the employment of SPT against Pseudomonas biofilms and Fap amyloid, or the possible mechanisms of action are scarce. Here, SPT inhibited biofilm formation of P. aeruginosa ATCC 27853 on both plastic and glass surfaces, with an IC50 of 11.26 µg/mL and 0.27 µg/mL, respectively. The inhibitory effect of SPT on biofilm was also verified with optical microscopy of crystal violet-stained biofilms and with confocal microscopy. Additionally, SPT caused a dose-dependent decrease of bacterial viability (IC50 of 3.07 µg/mL) as demonstrated by MTT assay. Reduction of bacterial functional amyloids was also demonstrated, employing both fluorescence microscopy with thioflavin T and photometrical determination of Congo-red-positive compounds. Both viability and functional amyloids correlated significantly with biofilm inhibition. Finally, in silico molecular docking studies provided a mechanistic insight into the interaction of SPT with FapC or FapD, proving that both peptides are possible targets of SPT. These results offer new insights into the biofilm formation of P. aeruginosa and potentiate the involvement of SPT in the prevention and eradication of Pseudomonas biofilms. KEY POINTS: • Serrapeptase inhibits biofilm formation of P. aeruginosa on plastic and glass. • Biofilm inhibition correlated with reduced viability and functional amyloid levels. • In silico studies indicated that serrapeptase may target FapC and FapD peptides.

Oleuropein is a natural inhibitor of PAI-1-mediated proliferation in human ER-/PR- breast cancer cells.

PURPOSE: Elevated expression of PAI-1 has been widely linked with adverse outcomes in a variety of human cancers, such as breast, gastric and ovarian cancers, rendering PAI-1 a prognostic biomarker. As a result, several chemical inhibitors are currently being developed against PAI-1; however, the clinical setting where they might confer survival benefits has not yet been elucidated. METHODS: RNA sequencing data analysis from the TCGA/GTEx cancer portals (n = 3607 samples). In silico molecular docking analyses to predict functional macromolecule interactions. ER-/PR- (MDA-MB-231) and ER+/PR+ (MCF-7) breast cancer cell lines implemented to assess the effect of oleuropein as a natural inhibitor of PAI-1-mediated oncogenic proliferation. RESULTS: We show that high PAI-1 levels inversely correlate with ER and PR expressions in a wide panel of estrogen/progesterone-responsive human malignancies. By implementing an in silico molecular docking analysis, we identify oleuropein, a phenolic component of olive oil, as a potent PAI-1-binding molecule displaying increased affinity compared to the other olive oil constituents. We demonstrate that EVOO or oleuropein treatment alone may act as a natural PAI-1 inhibitor by incrementally destabilising PAI-1 levels selectively in ER-/PR- breast cancer cells, accompanied by downstream caspase activation and cell growth inhibition. In contrast, ER+/PR+ breast cancer cells, where PAI-1 expression is absent or low, do not adequately respond to treatment. CONCLUSIONS: Our study demonstrates an inverse correlation between PAI-1 and ESR1/PGR levels, as well as overall patient survival in estrogen/progesterone-responsive human tumours. With a focus on breast cancer, our data identify oleuropein as a natural PAI-1 inhibitor and suggest that oleuropein-mediated PAI-1 destabilisation may confer clinical benefit only in ER-/PR- tumours.

Evidence for lytic transglycosylase and ß-N-acetylglucosaminidase activities located at the polyhydroxyalkanoates (PHAs) granules of Thermus thermophilus HB8.

The thermophilic bacterium Thermus thermophilus HB8 accumulates polyhydroxyalkanoates (PHAs) as intracellular granules used by cells as carbon and energy storage compounds. PHAs granules were isolated from cells grown in sodium gluconate (1.5 % w/v) as carbon source. Lytic activities are strongly associated and act to the PHAs granules proved with various methods. Specialized lytic trasglycosylases (LTGs) are muramidases capable of locally degrading the peptidoglycan (PG) meshwork of Gram negative bacteria. These enzymes cleave the ß-1,4-glycosidic linkages between the N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) residues of PG. Lysozyme-like activity/-ies were detected using lysoplate assay. Chitinolytic activity/-ies, were detected as N-acetyl glucosaminidases (NAG) (E.C.3.2.1.5.52) hydrolyzing the synthetic substrate p-nitrophenyl-N-acetyl-ß-D-glucosaminide (pNP-GlcNAc) releasing pNP and GlcNAc. Using zymogram analysis two abundant LTGs were revealed hydrolyzing cell wall of Micrococcus lysodeikticus or purified PG incorporated as natural substrates, in SDS-PAGE and then renaturation. These proteins corresponded in a SDS-PAGE and Coomassie-stained gel in molecular mass of 110 and 32 kDa respectively, were analyzed by MALDI-MS (Matrix-assisted laser desorption/ionization-Mass Spectrometry). The 110 kDa protein was identified as an S-layer domain-containing protein [gi|336233805], while the 32 kDa similar to the hypothetical protein VDG1235_2196 (gi/254443957). Overall, the localization of PG hydrolases in PHAs granules appears to be involved to their biogenesis from membranes, and probably promoting septal PG splitting and daughter cell separation.

Hepatotoxicity assessment of innovative nutritional supplements based on olive-oil formulations enriched with natural antioxidants.

Introduction: This study focuses on the assessment of extra virgin olive-oil and olive fruit-based formulations enriched with natural antioxidants as potential nutritional supplements for alleviating symptoms and long-term consequences of illnesses whose molecular pathophysiology is affected by oxidative stress and inflammation, such as Alzheimer's disease (AD). Methods: Besides evaluating cell viability and proliferation capacity of human hepatocellular carcinoma HepG2 cells exposed to formulations in culture, hepatotoxicity was also considered as an additional safety measure using quantitative real-time PCR on RNA samples isolated from the cell cultures and applying approaches of targeted molecular analysis to uncover potential pathway effects through gene expression profiling. Furthermore, the formulations investigated in this work contrast the addition of natural extract with chemical forms and evaluate the antioxidant delivery mode on cell toxicity. Results: The results indicate minimal cellular toxicity and a significant beneficial impact on metabolic molecular pathways in HepG2 cell cultures, thus paving the way for innovative therapeutic strategies using olive-oil and antioxidants in dietary supplements to minimize the long-term effects of oxidative stress and inflammatory signals in individuals being suffered by disorders like AD. Discussion: Overall, the experimental design and the data obtained support the notion of applying innovative molecular methodologies and research techniques to evidently advance the delivery, as well as the scientific impact and validation of nutritional supplements and dietary products to improve public health and healthcare outcomes.

Therapeutic and Diagnostic Potential of Exosomes as Drug Delivery Systems in Brain Cancer.

Cancer is designated as one of the principal causes of mortality universally. Among different types of cancer, brain cancer remains the most challenging one due to its aggressiveness, the ineffective permeation ability of drugs through the blood-brain barrier (BBB), and drug resistance. To overcome the aforementioned issues in fighting brain cancer, there is an imperative need for designing novel therapeutic approaches. Exosomes have been proposed as prospective "Trojan horse" nanocarriers of anticancer theranostics owing to their biocompatibility, increased stability, permeability, negligible immunogenicity, prolonged circulation time, and high loading capacity. This review provides a comprehensive discussion on the biological properties, physicochemical characteristics, isolation methods, biogenesis and internalization of exosomes, while it emphasizes their therapeutic and diagnostic potential as drug vehicle systems in brain cancer, highlighting recent advances in the research field. A comparison of the biological activity and therapeutic effectiveness of several exosome-encapsulated cargo including drugs and biomacromolecules underlines their great supremacy over the non-exosomal encapsulated cargo in the delivery, accumulation, and biological potency. Various studies on cell lines and animals give prominence to exosome-based nanoparticles (NPs) as a promising and alternative approach in the management of brain cancer.

Flagellin gene (fliC) of Thermus thermophilus HB8: characterization of its product and involvement to flagella assembly and microbial motility.

Thermus thermophilus HB8 flagellin protein (FliC) is encoded by the TTHC004 (fliC) gene, which is located in the pTT8 plasmid of the bacterium. Flagellin monomer and flagella fibres were isolated from a culture of T. thermophilus grown in rich medium, or in mineral salt medium with sodium gluconate as the carbon source. Western blot immunodetection with anti-FliC revealed a stable complex (FliC)(1)(FliS)(2) of flagellin (FliC, 27.7 kDa) with a homodimer of FliS (FliS, 18.2 kDa) that are encoded by TTHC004 and TTHC003 genes, respectively. The complex is dissociable at low pHs and/or by heat treatment. Glycan staining of purified flagella and treatment with N-glycosidase F suggested that flagellin of T. thermophilus is a glycosylated protein. Size exclusion chromatography revealed that flagellar filaments (FliC) have a molecular mass higher than 200 kDa. The formation of flagella is enhanced after prolonged cultivation time where phosphate and other nutrient were depleted, giving in the bacterium considerable swimming motility in low viscosity media.

Salivary GFAP as a potential biomarker for diagnosis of mild cognitive impairment and Alzheimer's disease and its correlation with neuroinflammation and apoptosis.

Glial fibrillary acidic protein (GFAP) is the main constituent of the astrocytic cytoskeleton, overexpressed during reactive astrogliosis-a hallmark of Alzheimer's Disease (AD). GFAP and established biomarkers of neurodegeneration, inflammation, and apoptosis have been determined in the saliva of amnestic-single-domain Mild Cognitive Impairment (MCI) (Ν = 20), AD (Ν = 20) patients, and cognitively healthy Controls (Ν = 20). Salivary GFAP levels were found significantly decreased in MCI and AD patients and were proven an excellent biomarker for discriminating Controls from MCI or AD patients. GFAP levels correlate with studied biomarkers and Aß42, IL-1ß, and caspase-8 are its main predictors.

Involvement and relationship of bacterial lipopolysaccharides and cyclooxygenases levels in Alzheimer's Disease and Mild Cognitive Impairment patients.

This study reports elevated levels of bacterial lipopolysaccharides (LPSs) and cyclooxygenases (COX-1/2) in blood serum and cerebrospinal fluid (CSF) of Alzheimer's Disease (AD) and Mild Cognitive Impairment (MCI) patients compared to cognitively healthy individuals, indicating LPSs as promising biomarkers, especially in serum. LPSs, in both fluids, positively correlate with COX-1/2, Αß42 and tau and negatively with mental state. Furthermore, COX-2 is the main determinant of LPSs presence in serum, whereas COX-1 in CSF. These results underline the significance of microbial/ inflammatory involvement in dementia and offer novel perspectives on the roles of LPSs and COX in pathogenesis of AD.

Unraveling the binding mechanism of an Oxovanadium(IV) - Curcumin complex on albumin, DNA and DNA gyrase by in vitro and in silico studies and evaluation of its hemocompatibility.

An oxovanadium(IV) - curcumin based complex, viz. [VO(cur)(2,2´-bipy)(H2O)] where cur is curcumin and bipy is bipyridine, previously synthesized, has been studied for interaction with albumin and DNA. Fluorescence emission spectroscopy was used to evaluate the interaction of the complex with bovine serum albumin (BSA) and the BSA-binding constant (Kb) was calculated to be 2.56 x 105 M-1, whereas a single great-affinity binding site was revealed. Moreover, the hemocompatibility test demonstrated that the complex presented low hemolytic fraction (mostly below 1%), in all concentrations tested (0-250 µΜ of complex, 5% DMSO) assuring a safe application in interaction with blood. The binding of the complex to DNA was also investigated using absorption, fluorescence, and viscometry methods indicating a binding through a minor groove mode. From competitive studies with ethidium bromide the apparent binding constant value to DNA was estimated to be 4.82 x 106 M-1. Stern-Volmer quenching phenomenon gave a ΚSV constant [1.92 (± 0.05) x 104 M-1] and kq constant [8.33 (± 0.2) x 1011 M-1s-1]. Molecular docking simulations on the crystal structure of BSA, calf thymus DNA, and DNA gyrase, as well as pharmacophore analysis for BSA target, were also employed to study in silico the ability of [VO(cur)(2,2´-bipy)(H2O)] to bind to these target bio-macromolecules and explain the observed in vitro activity.

Sunflower seed oil and oleic acid utilization for the production of rhamnolipids by Thermus thermophilus HB8.

The potential production of rhamnolipids was demonstrated using the thermophilic eubacterium Thermus thermophilus HB8 and sunflower seed oil or oleic acid as carbon sources. Sunflower seed oil was directly hydrolyzed by secretion of lipase and became a favorable carbon source for rhamnolipids production. Rhamnolipids levels were attainted high values, comparable to those produced by Pseudomonas strains from similar sources. Rhamnolipids synthesis in oleic acid exhibited a long period of induction, while in sunflower seed oil, the synthesis is more rapid. Glucose resulted in a more protracted period of rhamnolipids production after exhaustion of each or both carbon sources. Both mono- and di-rhamnolipids were identified by thin-layer chromatography (TLC) in the total rhamnolipids extract. The molecular composition of the produced biosurfactant was evaluated by Fourier transform infrared (FTIR) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and LC-MS analysis. Furthermore, secretion of rhamnolipids was confirmed on agar plates. The antimicrobial activity of rhamnolipids was detected against the bacterium Micrococcus lysodeikticus using a lysoplate assay. These results demonstrate that rhamnolipids produced in these substrates can be useful in both environmental and food industry applications by using cheap oil wastes. The alternative use of this thermophilic microorganism opens a new perspective concerning the valorization of wastes containing plant oils or frying oils to reduce the cost of rhamnolipids production.

Modeling and Targeting Alzheimer's Disease With Organoids.

Human neurodegenerative diseases, such as Alzheimer's disease (AD), are not easily modeled in vitro due to the inaccessibility of brain tissue and the level of complexity required by existing cell culture systems. Three-dimensional (3D) brain organoid systems generated from human pluripotent stem cells (hPSCs) have demonstrated considerable potential in recapitulating key features of AD pathophysiology, such as amyloid plaque- and neurofibrillary tangle-like structures. A number of AD brain organoid models have also been used as platforms to assess the efficacy of pharmacological agents in disease progression. However, despite the fact that stem cell-derived brain organoids mimic early aspects of brain development, they fail to model complex cell-cell interactions pertaining to different regions of the human brain and aspects of natural processes such as cell differentiation and aging. Here, we review current advances and limitations accompanying several hPSC-derived organoid methodologies, as well as recent attempts to utilize them as therapeutic platforms. We additionally discuss comparative benefits and disadvantages of the various hPSC-derived organoid generation protocols and differentiation strategies. Lastly, we provide a comparison of hPSC-derived organoids to primary tissue-derived organoids, examining the future potential and advantages of both systems in modeling neurodegenerative disorders, especially AD.

Structurally characterized gallium-chrysin complexes with anticancer potential.

Chemotherapeutic metal-based compounds are effective anticancer agents; however, their cytotoxic profile and significant side effects limit their wide application. Natural products, especially flavonoids, are a prominent alternative source of anticancer agents that can be used as ligands for the generation of new bioactive complexes with metal ions of known biochemical and pharmacological activities. Herein, we present the synthesis and detailed structural and physicochemical characterizations of three novel complex assemblies of Ga(iii) with the flavonoid chrysin and the ancillary aromatic chelators 1,10-phenanthroline, 2,2'-bipyridine and imidazole. The complexes constitute the only crystallographically characterized structures having a metal core from the boron group elements and a flavonoid as the ligand. The in vitro biological evaluation of the three complexes in a series of cancer cell lines of different origin established their cytotoxicity and ROS generating potential. In particular, the Ga(iii)-chrysin-imidazole complex displayed the highest anticancer efficacy against all cancer cell lines with IC50 values in the low micromolar range (<1.18 µM), a result worth further investigation.

Synthesis, physicochemical characterization and biological properties of two novel Cu(II) complexes based on natural products curcumin and quercetin.

Curcumin and quercetin are two of the most prominent natural polyphenols with a diverse spectrum of beneficial properties, including antioxidant, anti-inflammatory, chemopreventive and chemotherapeutic activity. The complexation of these natural products with bioactive transition metal ions can lead to the generation of novel metallodrugs with enhanced biochemical and pharmacological activities. Within this framework, the synthesis and detailed structural and physicochemical characterization of two novel complex assemblies of Cu(II) with curcumin and quercetin and the ancillary aromatic chelator 2,2'-bipyridine is presented. The two complexes represent the only crystallographically characterized structures with Cu(II) as the central metal ion and curcumin or quercetin as the ligands. The new complexes were biologically evaluated in vitro for their antioxidant potential, both exhibiting strong scavenging activity in the 2,2-diphenyl-1-picrylhydrazyl assay, and their plasmid DNA binding/cleavage properties. Both complexes appear to be non-toxic in the eukaryotic experimental model Saccharomyces cerevisiae and merit further investigation of their pharmacological profile.

An extracellular polyhydroxybutyrate depolymerase in Thermus thermophilus HB8.

The thermophilic bacterium Thermus thermophilus HB8 has been characterized as a polyhydroxybutyrate (PHB)-degrading microorganism since it grows efficiently and forms clear zones on agar plates containing PHB as sole carbon source. T. thermophilus extracellular PHB depolymerase was purified to homogeneity using an affinity chromatography protocol. The purified enzyme was estimated to have an apparent molecular mass of 42 kDa. The extracellular PHB depolymerase gene was identified as the TTHA0199 gene product of T. thermophilus HB8. The amino acid sequence of the TTHA0199 gene product shared significant homologies to other carboxylesterases. A catalytic triad was identified consisting of S(183), E(310), and H(405). A pentapeptide sequence (GX(1)SX(2)G) exists within the molecule, characteristic for PHB depolymerases (lipase box) and for other serine hydrolases. Purified extracellular PHB depolymerase was stable at high temperatures with an optimum activity at pH 8.0. The apparent Km value of the purified enzyme for PHB was 53 microg/ml. As the main product of the enzymic hydrolysis of PHB, the monomer 3-hydroxybutyrate was identified, suggesting that the enzyme acts principally as an exo-type hydrolase.

Homoleptic and heteroleptic silver(I) complexes bearing diphosphane and thioamide ligands: Synthesis, structures, DNA interactions and antibacterial activity studies.

Three silver(I) complexes bearing different combinations of diphosphanes and N-heterocyclic thioamides or thioamidates as ligands have been synthesized and structurally characterized: the ionic, homoleptic compound [Ag(xantphos)2][BF4] (1), where xantphos = 4,5-bis(diphenylphosphano)-9,9-dimethyl-xanthene, and the neutral, heteroleptic compounds [Ag(xantphos)(κ-S-pymt)] (2), where pymt = pyrimidine-2-thiolate, and [AgCl(dppbz)(κ-S-mtdztH)] (3), where dppbz = bis(diphenylphosphano)benzene and mtdztH = 5-methyl-1,3,4-thiadiazole-2-thione. X-ray crystallography studies reveal tetrahedral coordination environments around the silver(I) ions in compounds 1 and 3, while a trigonal planar arrangement of the P2S donor set has been found around the metal center in compound 2. The interaction of the three compounds with calf-thymus DNA was monitored by UV-vis spectroscopy, DNA-viscosity measurements and indirectly by testing their ability to compete with ethidium bromide for DNA intercalation sites studied by fluorescence emission spectroscopy. Intercalation was revealed as the most possible binding mode for the neutral compounds 2 and 3 and electrostatic interactions for the cationic complex [Ag(xantphos)2]+ in 1. Complexes 1-3 have also been found to display moderate in vitro antibacterial activity against the Gram-positive B. cereus, S. aureus and the Gram-negative E. coli bacterial strains, with the homoleptic bis-phosphane silver(I) compound 1 exhibiting a lower activity than the other two neutral compounds.

Magnetic cationic liposomal nanocarriers for the efficient drug delivery of a curcumin-based vanadium complex with anticancer potential.

In this work novel magnetic cationic liposomal nanoformulations were synthesized for the encapsulation of a crystallographically defined ternary V(IV)-curcumin-bipyridine (VCur) complex with proven bioactivity, as potential anticancer agents. The liposomal vesicles were produced via the thin film hydration method employing N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium (DOTAP) and egg phosphatidylcholine lipids and were magnetized through the addition of citric acid surface-modified monodispersed magnetite colloidal magnetic nanoparticles. The obtained nanoformulations were evaluated for their structural and textural properties and shown to have exceptional stability and enhanced solubility in physiological media, demonstrated by the entrapment efficiency and loading capacity results and the in vitro release studies of their cargo. Furthermore, the generated liposomal formulations preserved the superparamagnetic behavior of the employed magnetic core maintaining the physicochemical and morphological requirements for targeted drug delivery applications. The novel nanomaterials were further biologically evaluated for their DNA interaction potential and were found to act as intercalators. The findings suggest that the positively charged magnetic liposomal nanoformulations can generate increased concentration of their cargo at the DNA site, offering a further dimension in the importance of cationic liposomes as nanocarriers of hydrophobic anticancer metal ion complexes for the development of new multifunctional pharmaceutical nanomaterials with enhanced bioavailability and targeted antitumor activity.

A palladium(II) complex with the Schiff base 4-chloro-2-(N-ethyliminomethyl)-phenol: Synthesis, structural characterization, and in vitro and in silico biological activity studies.

The synthesis and characterization of the Pd(II) complex of the formula [Pd(L)2] 1 with the Schiff base 4-chloro-2-(N-ethyliminomethyl)-phenol (HL) as derived in situ via the condensation reaction of 5-chloro-salicylaldehyde and ethylamine was undertaken. The structure of 1 was verified by single-crystal X-ray crystallography. The ability of 1 to interact with calf-thymus (CT) DNA was studied by UV-vis and viscosity experiments, and its ability to displace ethidium bromide (EB) from the DNA-EB conjugate was revealed by fluorescence spectroscopy. It was found that intercalation is the most possible mode of interaction with CT DNA. Additionally, DNA electrophoretic mobility experiments showed that 1 interacts with the plasmid pBluescript SK(+) (pDNA) as proved by the formation of unusual mobility DNA bands and degradation of relaxed pDNA at concentration of 5 mM. The interaction of 1 with human (HSA) and bovine serum albumin (BSA) was monitored revealing its reversible binding to albumins. The complex showed noteworthy antimicrobial activity against one (Bacillus subtilis) of the five tested bacteria. In order to explain the described in vitro activity of the compound, we adopted molecular docking studies on the crystal structure of HSA, BSA, CT DNA and DNA-gyrase. Furthermore, in silico predictive tools have been employed to study the properties of the complex. The in silico studies are adopted on a multitude of proteins involved in cancer growth, as well as prediction of drug-induced changes of gene expression profile, protein- and mRNA-based prediction results, prediction of sites of metabolism, cytotoxicity for cancer cell lines, etc.

Synthesis, structure and interactions with DNA of novel tetranuclear, [Mn4(II/II/II/IV)] mixed valence complexes.

Reaction of Mn(II) with phenoxyalkanoic acids and di-2-pyridyl ketone oxime (Hpko) leads to neutral tetranuclear complexes of the general formula Mn(4)(O)(pko)(4)(phenoxyalkanoato)(4) (phenoxyalkanoic acids: H-mcpa=2-methyl-4-chloro-phenoxy-acetic acid, H-2,4,5-T=2,4,5-trichloro-phenoxy-acetic acid or H3,4-D=3,4-dichloro-phenoxy-acetic acid). The compounds were synthesized by adding di-2-pyridyl ketone oxime to MnCl(2) in the presence of the sodium salts of the alkanoic acids in methanol. The crystal structure of Mn(4)(II/II/II/IV)(O)(pko)(4)(2,4,5-T)(4).2.5CH(3)OH.0.25H(2)O 1 shows that the complex consists of a [Mn(4)(mu(4)-O)](8+) core with a Mn(IV) and 3 Mn(II) ions in octahedral environment and a mu(4)-O atom bridging the four manganese ions. Spectroscopic studies of the interaction of these tetranuclear clusters with DNA showed that these compounds bind to dsDNA. The binding strength of the Mn(4)(II/II/II/IV)(O)(pko)(4)(2,4,5-T)(4) complex for calf thymus DNA is equal to 1.1x10(4)M(-1). Among the deoxyribonucleotides they bind preferentially to deoxyguanylic acid (dGMP). Competitive studies with ethidium bromide (EthBr) showed that the Mn(4)(II/II/II/IV)(O)(pko)(4)(2,4,5-T)(4) complex exhibited the ability to displace the DNA-bound EthBr indicating that the complex binds to DNA via intercalation in strong competition with EthBr for the intercalative binding site. Additionally, DNA electrophoretic mobility experiments showed that all three complexes, at low cluster concentration, are obviously capable of binding to pDNA causing its cleavage (relaxation) at physiological pH and temperature. At higher cluster concentration, catenated dimer forms of pDNA was formed.