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Publikation

Soboleva, A.; Mavropulo-Stolyarenko, G.; Karonova, T.; Thieme, D.; Hoehenwarter, W.; Ihling, C.; Stefanov, V.; Grishina, T.; Frolov, A.; Multiple Glycation Sites in Blood Plasma Proteins as an Integrated Biomarker of Type 2 Diabetes Mellitus Int. J. Mol. Sci. 20, 2329, (2019) DOI: 10.3390/ijms20092329

Type 2 diabetes mellitus (T2DM) is one of the most widely spread metabolic diseases. Because of its asymptomatic onset and slow development, early diagnosis and adequate glycaemic control are the prerequisites for successful T2DM therapy. In this context, individual amino acid residues might be sensitive indicators of alterations in blood glycation levels. Moreover, due to a large variation in the half-life times of plasma proteins, a generalized biomarker, based on multiple glycation sites, might provide comprehensive control of the glycemic status across any desired time span. Therefore, here, we address the patterns of glycation sites in highly-abundant blood plasma proteins of T2DM patients and corresponding age- and gender-matched controls by comprehensive liquid chromatography-mass spectrometry (LC-MS). The analysis revealed 42 lysyl residues, significantly upregulated under hyperglycemic conditions. Thereby, for 32 glycation sites, biomarker behavior was demonstrated here for the first time. The differentially glycated lysines represented nine plasma proteins with half-lives from 2 to 21 days, giving access to an integrated biomarker based on multiple protein-specific Amadori peptides. The validation of this biomarker relied on linear discriminant analysis (LDA) with random sub-sampling of the training set and leave-one-out cross-validation (LOOCV), which resulted in an accuracy, specificity, and sensitivity of 92%, 100%, and 85%, respectively.
Publikation

Shumilina, J.; Kusnetsova, A.; Tsarev, A.; Janse van Rensburg, H. C.; Medvedev, S.; Demidchik, V.; Van den Ende, W.; Frolov, A.; Glycation of Plant Proteins: Regulatory Roles and Interplay with Sugar Signalling? Int. J. Mol. Sci. 20, 2366, (2019) DOI: 10.3390/ijms20092366

Glycation can be defined as an array of non-enzymatic post-translational modifications of proteins formed by their interaction with reducing carbohydrates and carbonyl products of their degradation. Initial steps of this process rely on reducing sugars and result in the formation of early glycation products—Amadori and Heyns compounds via Schiff base intermediates, whereas their oxidative degradation or reactions of proteins with α-dicarbonyl compounds yield a heterogeneous group of advanced glycation end products (AGEs). These compounds accompany thermal processing of protein-containing foods and are known to impact on ageing, pathogenesis of diabetes mellitus and Alzheimer’s disease in mammals. Surprisingly, despite high tissue carbohydrate contents, glycation of plant proteins was addressed only recently and its physiological role in plants is still not understood. Therefore, here we summarize and critically discuss the first steps done in the field of plant protein glycation during the last decade. We consider the main features of plant glycated proteome and discuss them in the context of characteristic metabolic background. Further, we address the possible role of protein glycation in plants and consider its probable contribution to protein degradation, methylglyoxal and sugar signalling, as well as interplay with antioxidant defense.
Publikation

Shaaban, S.; Ashmawy, A. M.; Negm, A.; Wessjohann, L. A.; Synthesis and biochemical studies of novel organic selenides with increased selectivity for hepatocellular carcinoma and breast adenocarcinoma Eur. J. Med. Chem. 179, 515-526, (2019) DOI: 10.1016/j.ejmech.2019.06.075

Nineteen organoselenides were synthesized and tested for their intrinsic cytotoxicity in hepatocellular carcinoma (HepG2) and breast adenocarcinoma (MCF-7) cell lines and their corresponding selective cytotoxicity (SI) was estimated using normal lung fibroblast (WI-38) cells. Most of the organic selenides exhibited good anticancer activity, and this was more pronounced in HepG2 cells. Interestingly, the naphthoquinone- (5), thiazol- (12), and the azo-based (13) organic selenides demonstrated promising SI (up to 76). Furthermore, the amine 4c, naphthoquinone 5, and azo-based 13 and 15 organic selenides were able to down-regulate the expression of Bcl-2 and up-regulate the expression levels of IL-2, IL-6 and CD40 in HepG2 cells compared to untreated cells. Moreover, most of the synthesized candidates manifested good free radical-scavenging and GPx-like activities comparable to vitamin C and ebselen. The obtained results suggested that some of the presented organoselenium candidates have promising anti-HepG2 and antioxidant activities.
Publikation

Seixas, N.; Ravanello, B. B.; Morgan, I.; Kaluđerović, G. N.; Wessjohann, L. A.; Chlorambucil Conjugated Ugi Dendrimers with PAMAM-NH2 Core and Evaluation of Their Anticancer Activity Pharmaceutics 11, 59, (2019) DOI: 10.3390/pharmaceutics11020059

Herein, a new Ugi multicomponent reaction strategy is described to enhance activity and solubility of the chemotherapeutic drug chlorambucil through its conjugation to poly(amidoamine) (PAMAM-NH2) dendrimers with the simultaneous introduction of lipidic (i-Pr) and cationic (–NH2) or anionic (–COOH) groups. Standard viability assays were used to evaluate the anticancer potential of the water-soluble dendrimers against PC-3 prostate and HT-29 colon cancer cell lines, as well as non-cancerous mouse NIH3T3 fibroblasts. It could be demonstrated that the anticancer activity against PC-3 cells was considerably improved when both chlorambucil and –NH2 (cationic) groups were present on the dendrimer surface (1b). Additionally, this dendrimer showed activity only against the prostate cancer cells (PC-3), while it did not affect colon cancer cells and fibroblasts significantly. The cationic chlorambucil-dendrimer 1b blocks PC-3 cells in the G2/M phase and induces caspase independent apoptosis.
Publikation

Podolskaya, E. P.; Gladchuk, A. S.; Keltsieva, O. A.; Dubakova, P. S.; Silyavka, E. S.; Lukasheva, E.; Zhukov, V.; Lapina, N.; Makhmadalieva, M. R.; Gzgzyan, A. M.; Sukhodolov, N. G.; Krasnov, K. A.; Selyutin, A. A.; Frolov, A.; Thin Film Chemical Deposition Techniques as a Tool for Fingerprinting of Free Fatty Acids by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Anal. Chem. 91, 1636-1643, (2019) DOI: 10.1021/acs.analchem.8b05296

Metabolic fingerprinting is a powerful analytical technique, giving access to high-throughput identification and relative quantification of multiple metabolites. Because of short analysis times, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is the preferred instrumental platform for fingerprinting, although its power in analysis of free fatty acids (FFAs) is limited. However, these metabolites are the biomarkers of human pathologies and indicators of food quality. Hence, a high-throughput method for their fingerprinting is required. Therefore, here we propose a MALDI-TOF-MS method for identification and relative quantification of FFAs in biological samples of different origins. Our approach relies on formation of monomolecular Langmuir films (LFs) at the interphase of aqueous barium acetate solution, supplemented with low amounts of 2,5-dihydroxybenzoic acid, and hexane extracts of biological samples. This resulted in detection limits of 10–13–10–14 mol and overall method linear dynamic range of at least 4 orders of magnitude with accuracy and precision within 2 and 17%, respectively. The method precision was verified with eight sample series of different taxonomies, which indicates a universal applicability of our approach. Thereby, 31 and 22 FFA signals were annotated by exact mass and identified by tandem MS, respectively. Among 20 FFAs identified in Fucus algae, 14 could be confirmed by gas chromatography-mass spectrometry.
Publikation

Feilcke, R.; Arnouk, G.; Raphane, B.; Richard, K.; Tietjen, I.; Andrae-Marobela, K.; Erdmann, F.; Schipper, S.; Becker, K.; Arnold, N.; Frolov, A.; Reiling, N.; Imming, P.; Fobofou, S. A. T.; Biological activity and stability analyses of knipholone anthrone, a phenyl anthraquinone derivative isolated from Kniphofia foliosa Hochst. J. Pharm. Biomed. Anal. 174, 277-285, (2019) DOI: 10.1016/j.jpba.2019.05.065

Knipholone (1) and knipholone anthrone (2), isolated from the Ethiopian medicinal plant Kniphofia foliosa Hochst. are two phenyl anthraquinone derivatives, a compound class known for biological activity. In the present study, we describe the activity of both 1 and 2 in several biological assays including cytotoxicity against four human cell lines (Jurkat, HEK293, SH-SY5Y and HT-29), antiplasmodial activity against Plasmodium falciparum 3D7 strain, anthelmintic activity against the model organism Caenorhabditis elegans, antibacterial activity against Aliivibrio fischeri and Mycobacterium tuberculosis and anti-HIV-1 activity in peripheral blood mononuclear cells (PBMCs) infected with HIV-1c. In parallel, we investigated the stability of knipholone (2) in solution and in culture media. Compound 1 displays strong cytotoxicity against Jurkat, HEK293 and SH-SY5Y cells with growth inhibition ranging from approximately 62–95% when added to cells at 50 μM, whereas KA (2) exhibits weak to strong activity with 26, 48 and 70% inhibition of cell growth, respectively. Both 1 and 2 possess significant antiplasmodial activity against Plasmodium falciparum 3D7 strain with IC50 values of 1.9 and 0.7 μM, respectively. These results complement previously reported data on the cytotoxicity and antiplasmodial activity of 1 and 2. Furthermore, compound 2 showed HIV-1c replication inhibition (growth inhibition higher than 60% at tested concentrations 0.5, 5, 15 and 50 μg/ml and an EC50 value of 4.3 μM) associated with cytotoxicity against uninfected PBMCs. The stability study based on preincubation, HPLC and APCI-MS (atmospheric-pressure chemical ionization mass spectrometry) analysis indicates that compound 2 is unstable in culture media and readily oxidizes to form compound 1. Therefore, the biological activity attributed to 2 might be influenced by its degradation products in media including 1 and other possible dimers. Hence, bioactivity results previously reported from this compound should be taken with caution and checked if they differ from those of its degradation products. To the best of our knowledge, this is the first report on the anti-HIV activity and stability analysis of compound 2.
Publikation

Farag, M. A.; El-Kersh, D. M.; Ehrlich, A.; Choucry, M. A.; El-Seedi, H.; Frolov, A.; Wessjohann, L. A.; Variation in Ceratonia siliqua pod metabolome in context of its different geographical origin, ripening stage and roasting process Food Chem. 283, 675-687, (2019) DOI: 10.1016/j.foodchem.2018.12.118

Carob is a legume tree of a considerable commercial importance for the flavor and sweet industry. In this context, it is cultivated mostly for its pods, which are known for their nutritive value and multiple health benefits. However, metabolite patterns, underlying these properties are still mostly uncharacterized. In this study, the role of geographical origin, ontogenetic changes and thermal processing on the Ceratonia siliqua pod metabolome was assessed by mass spectrometry (MS)-based metabolomics. Thereby, a total of 70 fruits primary metabolites, represented mainly by carbohydrates, organic and amino acids were detected. Analysis of secondary bioactive metabolites assessed by ultra-high-performance liquid chromatography-electrospray ionization high resolution mass spectrometry (UHPLC-ESI-HR-MS) revealed in total 83 signals. The major signals, most significantly contributing in discrimination of C. siliqua specimens were assigned to tannins and flavonoids. PCA models derived from either UHPLC-MS or GC-MS proved to be powerful tools for discrimination of C. siliqua specimens.
Publikation

Drača, D.; Mijatović, S.; Krajnović, T.; Pristov, J. B.; Đukić, T.; Kaluđerović, G. N.; Wessjohann, L. A.; Maksimović-Ivanić, D.; The synthetic tubulysin derivative, tubugi-1, improves the innate immune response by macrophage polarization in addition to its direct cytotoxic effects in a murine melanoma model Exp. Cell Res. 380, 159-170, (2019) DOI: 10.1016/j.yexcr.2019.04.028

Synthetic tubugis are equally potent but more stable than their natural forms. Their anticancer potential was estimated on a solid melanoma in vitro and in vivo. Tubugi-1 induced the apoptosis in B16 cells accompanied with strong intracellular production of reactive species, subsequently imposing glutathione and thiol group depletion. Paradoxically, membrane lipids were excluded from the cascade of intracellular oxidation, according to malondialdehyde decrease. Although morphologically apoptosis was typical, externalization of phosphatidylserine (PS) as an early apoptotic event was not detected. Even their exposition is pivotal for apoptotic cell eradication, primary macrophages successfully eliminated PS-deficient tubugi-1 induced apoptotic cells. The tumor volume in animals exposed to the drug in therapeutic mode was reduced in comparison to control as well as to paclitaxel-treated animals. Importantly, macrophages isolated from tubugi-1 treated animals possessed conserved phagocytic activity and were functionally and phenotypically recognized as M1. The cytotoxic effect of tubugi-1 is accomplished through its ability to polarize the macrophages toward M1, probably by PS independent apoptotic cell engulfment. The unique potential of tubugi-1 to prime the innate immune response through the induction of a specific pattern of tumor cell apoptosis can be of extraordinary importance from fundamental and applicable aspects.
Publikation

Drača, D.; Mijatović, S.; Krajnović, T.; Kaluđerović, G. N.; Wessjohann, L. A.; Maksimović-Ivanić, D.; Synthetic Tubulysin Derivative, Tubugi-1, Against Invasive Melanoma Cells: The Cell Death Triangle Anticancer Res. 39, 5403-5415, (2019) DOI: 10.21873/anticanres.13734

Background/Aim: Tubugi-1 is a more stable and accessible synthetic counterpart of natural tubulysins. This study aimed to evaluate its cytotoxic potential against anaplastic human melanoma cells. Materials and Methods: The viability of A-375 cells was determined by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet assay. The type of cell death and proliferative rate were investigated using flow cytometry and fluorescent microscopy, while the molecular background was evaluated by western blot. Results: Tubugi-1 reduced the viability of A-375 cells, inducing massive micronucleation, followed by augmented expression of inhibitor of nuclear factor-κB and caspase-2, typical of a mitotic catastrophe. Disturbed proliferation and G2M block with prominent caspase activity, weakened the expression of B-cell lymphoma 2 and B-cell lymphoma 2-associated X transient up-regulation, coexisted with intensive autophagy. Specific inhibition of autophagy by chloroquine resulted in conversion from mitotic catastrophe to rapid apoptosis. Conclusion: Multilevel anticancer action of tubugi-1 is extended by co-application of an autophagy inhibitor, giving a new dimension in further preclinical advancement of this potential agent.
Publikation

Zoufal, V.; Mairinger, S.; Krohn, M.; Wanek, T.; Filip, T.; Sauberer, M.; Stanek, J.; Traxl, A.; Schuetz, J. D.; Kuntner, C.; Pahnke, J.; Langer, O.; Influence of Multidrug Resistance-Associated Proteins on the Excretion of the ABCC1 Imaging Probe 6-Bromo-7-[11C]Methylpurine in Mice Mol. Imaging Biol. 21, 306-316, (2019) DOI: 10.1007/s11307-018-1230-y

PurposeMultidrug resistance-associated proteins (MRPs) mediate the hepatobiliary and renal excretion of many drugs and drug conjugates. The positron emission tomography (PET) tracer 6-bromo-7-[11C]methylpurine is rapidly converted in tissues by glutathione-S-transferases into its glutathione conjugate, and has been used to measure the activity of Abcc1 in the brain and the lungs of mice. Aim of this work was to investigate if the activity of MRPs in excretory organs can be measured with 6-bromo-7-[11C]methylpurine.ProceduresWe performed PET scans with 6-bromo-7-[11C]methylpurine in groups of wild-type, Abcc4(−/−) and Abcc1(−/−) mice, with and without pre-treatment with the prototypical MRP inhibitor MK571.Results6-Bromo-7-[11C]methylpurine-derived radioactivity predominantly underwent renal excretion. In blood, MK571 treatment led to a significant increase in the AUC and a decrease in the elimination rate constant of radioactivity (kelimination,blood). In the kidneys, there were significant decreases in the rate constant for radioactivity uptake from the blood (kuptake,kidney), kelimination,kidney, and the rate constant for tubular secretion of radioactivity (kurine). Experiments in Abcc4(−/−) mice indicated that Abcc4 contributed to renal excretion of 6-bromo-7-[11C]methylpurine-derived radioactivity.ConclusionsOur data suggest that 6-bromo-7-[11C]methylpurine may be useful to assess the activity of MRPs in the kidneys as well as in other organs (brain, lungs), although further work is needed to identify the MRP subtypes involved in the disposition of 6-bromo-7-[11C]methylpurine-derived radioactivity.

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