Vassiliki Theodorou
University of Ioannina
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Featured researches published by Vassiliki Theodorou.
Inorganica Chimica Acta | 1982
Vassiliki Theodorou; I. Photaki; Nick Hadjiliadis; R.W. Gellert; Robert Bau
Abstract IR, 1 H NMR and 13 C NMR spectra of cis -Pt(S-EtCys)Cl 2 have been analyzed and interpreted in favor of a structure which the ethyl-cysteine ligand coordinates through its S and N atoms. Additionally, the 1 H and 13 C NMR spectra show the existence of two diastereomers, differing in their absolute configuration at sulfur. These conclusions were confirmed by a single-crystal X-ray structure determination, which showed the presence of both diastereomers in the unit cell. Crystallographic details: cis -Pt(S-EtCys)Cl 2 crystallizes in the monoclinic space group P2 1 , with a = 8.336(6) A , b = 10.997(8) A , c = 15.097(9) A , β = 120.76(3)°, Z = 4. Final R factor = 0.054 for 1842 reflections.
Bioorganic & Medicinal Chemistry Letters | 1997
George Kokotos; Vassiliki Theodorou; Chryssa Tzougraki; Dieter Deforce; Elfreide G. Van den Eeckhout
A number of cis-dichloro[bis(aminocoumarin)]platinum(II) complexes have been synthesized and evaluated for their in vitro cytotoxicity against Caco-2T cells. The complex with 7-amino-4-trifluoromethylcoumarin as ligand has been found to be the most active (IC50 10 μg/ml) in this study.
Current Medicinal Chemistry | 2005
Andreas G. Tzakos; Petri Kursula; Anastassios N. Troganis; Vassiliki Theodorou; Theodore Tselios; Christos Svarnas; John Matsoukas; Vasso Apostolopoulos; Ioannis P. Gerothanassis
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by demyelination and loss of neurological function, local macrophage infiltrate and neuroantigen-specific CD4(+)T cells. MS arises from complex interactions between genetic, immunological, infective and biochemical mechanisms. Although the circumstances of MS etiology remain hypothetical, one persistent theme involves immune system recognition of myelin-specific antigens derived from myelin basic protein, the most abundant extrinsic myelin membrane protein, and/or another equally suitable myelin protein or lipid. Knowledge of the biochemical and physico-chemical properties of myelin proteins and lipids, particularly their composition, organization, structure and accessibility with respect to the compacted myelin multilayers, becomes central to understanding how and why myelin-specific antigens become selected during the development of MS. This review focuses on the current understanding of the molecular basis of MS with emphasis: (i) on the physical-chemical properties, organization, morphology, and accessibility of the proteins and lipids within the myelin multilayers; (ii) on the structure-function relationships and characterization of the myelin proteins relevant to the manifestation and evolution of MS; (iii) on conformational relationships between myelin epitopes which might become selected during the development of MS; (iv) on the structure of MHC/HLA in complex with MBP peptides as well as with TCR, which is crucial to the understanding of the pathogenesis of MS with the ultimate goal of designed antigen-specific treatments.
Bioorganic & Medicinal Chemistry Letters | 1998
George Kokotos; Vassiliki Theodorou; Violetta Constantinou-Kokotou; William A. Gibbons; Christos Roussakis
A number of lipophilic platinum(II) complexes of the general structures cis-[Pt(LA)2Cl2] and [Pt(LD)Cl2] were synthesised. Long chain amines (LA) and diamines (LD), prepared from lipidic amino acids, were used as ligands. The in vitro cytotoxicity of the complexes was evaluated against four cell lines (P388, NSCLC-N6, E39, M96). cis-Dichloro-bis(2-aminohexadecanol)platinum(II) was the most active against P388, NSCLC-N6 and E39 (IC50: 11 micrograms/ml, 25 micrograms/ml, 31 micrograms/ml), while dichloro(1,3-heptadecanediamine)platinum(II) presented the highest activity against M96 (IC50: 13 micrograms/ml).
ChemMedChem | 2010
Konstantinos Skobridis; Maria Kinigopoulou; Vassiliki Theodorou; Emilia Giannousi; Alison Russell; Rakhee Chauhan; Roberta Sala; Nicola Brownlow; Serafim Kiriakidis; Jan Domin; Andreas G. Tzakos; N J Dibb
Imatinib is a clinically important ATP analogue inhibitor that targets the tyrosine kinase domain of the intracellular Abl kinase and the PDGF receptor family. Imatinib has revolutionised the treatment of chronic myeloid leukaemia, which is caused by the oncogene Bcr–Abl and certain solid tumours that harbor oncogenic mutations of the PDGF receptor family. As a leading kinase inhibitor, imatinib also provides an excellent model system to investigate how changes in drug design impact biological activity, which is an important consideration for rational drug design. Herein we report a new series of imatinib derivatives that in general have greater activity against the family of PDGF receptors and poorer activity against Abl, as a result of modifications of the phenyl and N‐methylpiperazine rings. These new compounds provide a platform for further drug development against the therapeutically important PDGF receptor family and they also provide insight into the engineering of drugs with altered biological activity.
Amino Acids | 2013
Panagiotis Stathopoulos; Serafim Papas; Charalambos Pappas; Vassilios Mousis; Nisar Sayyad; Vassiliki Theodorou; Andreas G. Tzakos; Vassilios Tsikaris
Alkylation of sensitive amino acids during synthesis of biologically important peptides is a common and well-documented problem in Fmoc-based strategy. Herein, we probed for the first time an unexpected S-alkylation of Cys-containing peptides that occur during the final TFA cleavage of peptides from the Wang solid support. Through a battery of approaches (NMR, UV and LC–MS) the formed by-product was assigned as the alkylation of the cysteine sulfydryl group by the p-hydroxyl benzyl group derived from the acidic Wang linker decomposition. Factors affecting this side reaction were monitored and a protocol that minimizes the presence of the by-product is reported.
The FASEB Journal | 2015
Serafim Kiriakidis; Anne-Theres Henze; Ilona Kruszynska-Ziaja; Konstantinos Skobridis; Vassiliki Theodorou; Ewa Paleolog; Massimiliano Mazzone
Factor‐inhibiting hypoxia‐inducible factor (HIF)‐1 (FIH‐1) is an asparaginyl β‐hydroxylase enzyme that was initially found to hydroxylate the HIF‐α, preventing its transcriptional activity and leading to adaptive responses to hypoxia. More recently, other substrates, such as neurogenic locus notch homolog (Notch), have been found to be alternative FIH targets, but the biologic relevance of this regulation was never investigated. Given the key function of Notch in angiogenesis, we here investigate the role of FIH/Notch signaling in endothelial cells. We report that FIH‐1 silencing in HUVECs results in reduced growth and increased apoptosis. The knockdown of FIH is associated with increased Notch2 activity, leading to enhanced expression of the Notch target hairy/enhancer‐of‐split related with YRPW motif protein 1 (Hey‐1). Consistent with recent findings showing that Notch2 suppresses survivin (a key inhibitor of apoptosis), FIH targeting in HUVECs leads to selective repression of survivin in endothelial cells, thus promoting cell apoptosis and growth arrest. Our data support the concept that FIH‐1 may interact with Notch2 and repress its activity, thereby playing a critical role in controlling the survival of vascular endothelial cells. These findings might pave the way toward novel, antiangiogenic strategies in disorders that are characterized by excessive vascular growth, such as cancer and rheumatoid arthritis.—Kiriakidis, S., Henze, A.‐T., Kruszynska‐Ziaja, I., Skobridis, K., Theodorou, V., Paleolog, E. M., Mazzone, M. Factor‐inhibiting HIF‐1 (FIH‐1) is required for human vascular endothelial cell survival. FASEB J. 29, 2814‐2827 (2015). www.fasebj.org
Journal of Labelled Compounds and Radiopharmaceuticals | 2014
Vassiliki Theodorou; Konstantinos Skobridis; Dimitrios Alivertis; Ioannis P. Gerothanassis
This review is a critical survey of the literature that aims to highlight the most significant developments on synthetic strategies involving stable oxygen isotopes ([(17)O] and [(18)O]). The labeling methodologies are categorized in groups, according to the oxygen-containing functional group.
Supramolecular Chemistry | 2007
Konstantinos Skobridis; Vassiliki Theodorou; Dimitrios Alivertis; Wilhelm Seichter; Edwin Weber; Ingeborg Csöregh
Four crystalline inclusion compounds of the 2,2′-bis(9-hydroxy-9-fluorenyl)biphenyl host 1, containing diethylene glycol (1:1) (1a), bis(2-aminoethyl)amine (1:1) (1b), methacrylic acid (1:1) (1c) and 2-cyclopenten-1-one (1:2) (1d), have been studied by X-ray diffraction analysis from single crystals. Departure from the expectation, the multifunctional and conjugate functional guest molecules, potentially being able to offer multiple H donor-/acceptorships or other modes of polar interaction due to the conjugation, do not result in the formation of infinitely connected networks in the crystal structures. Instead of this, discrete 2:2 host–guest aggregates (1a, 1b), guest dimers (1c) and rather conventional host–guest units (1d) are found. Hence, inherent shielding effects of the host molecule owing to the fluorenyl moieties and the presence of a strong intramolecular hydrogen bond, impeding multiple intermolecular association, are not overcome by the merits of the guest molecules, showing that the host compound 1 is superior by structural constancy in its crystalline inclusions.
Inorganica Chimica Acta | 1993
Vassiliki Theodorou; Anna Nicolaou; Nick Hadjiliadis
Abstract Complexes of the general formulae [(dien)Pt(nucl)]Br2, with nucl=guanosine (guo), inosine (ino), xanthosine (xao) and 9-methyl guanine (9-MeG) were first isolated from the reactions of [(dien)PtBr]Br with the nucleosides. Further reactions between the [(dien)Pt(nucl)]Br 2 , [(dien)PtBr]Br and K 2 PtX 4 (XCl, Br) complexes produced new ones of formulae [(dien)Pt(nucl-H + )]Br, [{(dien)Pt} 2 (nucl-H + )](ClO 4 0) 3 , [(dien)Pt(nucl-H + )PtX 3 ] and [(dien)Pt(nucl)](PtX 4 ) (XCl, Br). All complexes were characterized by elemental analysis, conductivity measurements, IR and 1 H NMR spectra. All the nucleosides are firstly coordinated through their N 7 atoms. This is followed by an attack of a second Pt(II) atom at N 1 , after deprotonation of this site in the dinuclear complexes.