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Biochemistry. Biokhimiia Jan 2019Olivomycin A is a highly active antitumor drug that belongs to the family of aureolic acid antibiotics. The antitumor effect of olivomycin A is related to its ability to...
Olivomycin A is a highly active antitumor drug that belongs to the family of aureolic acid antibiotics. The antitumor effect of olivomycin A is related to its ability to bind to the DNA minor groove in GC-rich regions as Mg2+-coordinated complexes. Characterization of cellular targets of olivomycin A and its mechanism of action is crucial for the successful application of this antibiotic in clinical practice and development of semi-synthetic derivatives with improved pharmacological properties. Previously, we have shown that minor groove ligands are able to disrupt the key epigenetic process of DNA methylation. In this paper, we have studied the impact of olivomycin A and its improved semi-synthetic analogue N,N-dimethylaminoethylamide of 1'-des-(2,3-dihydroxy-n-butyroyl)-1'-carboxy-olivomycin A (olivamide) on the functioning of de novo DNA methyltransferase Dnmt3a (enzyme that carries out methylation of cytosine residues in the DNA CG-sites in eukaryotic cells) using an in vitro system consisting of the murine Dnmt3a catalytic domain and a 30-mer DNA duplex containing four consecutive GC pairs. We have shown that olivomycin A and olivamide inhibit Dnmt3a with IC of 6 ± 1 and 7.1 ± 0.7 μM, respectively. Neither olivomycin A nor olivamide interfered with the formation of the specific enzyme-substrate complex; however, olivomycin A prevented formation of the covalent DNA-Dnmt3a intermediate that is necessary for the methylation reaction to proceed. The inhibitory effects of olivomycin A and olivamide can be explained by the disruption of the enzyme catalytic loop movement through the DNA minor groove (the reaction stage that precedes the covalent bond formation between DNA and the enzyme). The results of this work indicate the epigenetic contribution to the antitumor effect of aureolic acid group antibiotics.
Topics: Animals; Antibiotics, Antineoplastic; DNA (Cytosine-5-)-Methyltransferases; DNA Methylation; DNA Methyltransferase 3A; Mice; Olivomycins; Protein Binding
PubMed: 30927527
DOI: 10.1134/S0006297919010085 -
International Journal of Molecular... Aug 2022Olivomycin A (OA), an antibiotic of the aureolic acid family, interferes with gene transcription upon forming complexes with GC-rich regions in the DNA minor groove. We...
Olivomycin A (OA), an antibiotic of the aureolic acid family, interferes with gene transcription upon forming complexes with GC-rich regions in the DNA minor groove. We demonstrate that the mechanism of transcriptional deregulation is not limited to OA interaction with GC-containing binding sites for transcription factors. Using electrophoretic mobility shift assays and DNAse I footprinting of cytomegalovirus (CMV) promoter fragments carrying OA-preferred GC tetrads (CMVwt), we showed OA binding specifically to GC islands. Replacement of G for A in these tetrads (CMVmut) abrogated OA binding. Furthermore, OA decreased RNA polymerase II (RNAPII) binding to the CMVwt promoter and inhibited the reporter gene expression. In line with the absence of OA binding sites in CMVmut DNA, the expression driven from this promoter was weakly sensitive to OA. In the endogenous genes OA decreased RNAPII on promoters and coding regions. In certain cases this phenomenon was concomitant with the increased histone 3 abundance. However, the sensitivity to OA did not correlate with GC patterns around transcription start sites, suggesting that certain GC stretches play unequal roles in OA-induced transcriptional perturbations. Thus, OA affects transcription via complex mechanisms in which GC tetranucleotide binding causes RNAPII/chromatin alterations differentially manifested in individual gene contexts.
Topics: Binding Sites; Chromatin; DNA; Olivomycins; Promoter Regions, Genetic; RNA Polymerase II; Transcription Factors; Transcription, Genetic
PubMed: 36012127
DOI: 10.3390/ijms23168871 -
Antibiotics (Basel, Switzerland) Oct 2020is one of the most dangerous pathogens. Bacterial resistance to antituberculosis drugs grows each year, but searching for new drugs is a long process. Testing for...
is one of the most dangerous pathogens. Bacterial resistance to antituberculosis drugs grows each year, but searching for new drugs is a long process. Testing for available drugs to find active against mycobacteria may be a good alternative. In this work, antibiotics of the aureolic acid group were tested on a model organism . We presumed that antibiotics of this group may be potential G4 ligands. However, this was not confirmed in our analyses. We determined the antimicrobial activity of these drugs and revealed morphological changes in the cell structure upon treatment. Transcriptomic analysis documented increased expression of and , involved in cell division. Therefore, drugs may affect cell division, possibly disrupting the function of the Z-ring and the formation of a septum. Additionally, a decrease in the transcription level of several indispensable genes, such as nitrate reductase subunits ( and ) and was shown. We concluded that the mechanism of action of aureolic acid and its related compounds may be similar to that bedaquiline and disturb the NAD+/NADH balance in the cell. All of this allowed us to conclude that aureolic acid derivatives can be considered as potential antituberculosis drugs.
PubMed: 33086595
DOI: 10.3390/antibiotics9100715 -
International Journal of Molecular... Jul 2020Olivomycin A (OA) exerts its cytotoxic potency due to binding to the minor groove of the G/C-rich DNA and interfering with replication and transcription. Screening of...
Olivomycin A (OA) exerts its cytotoxic potency due to binding to the minor groove of the G/C-rich DNA and interfering with replication and transcription. Screening of the complete set of tetranucleotide G/C sites by electrophoretic mobility gel shift assay (EMSA) revealed that the sites containing central GC or GG dinucleotides were able to bind OA, whereas the sites with the central CG dinucleotide were not. However, studies of equilibrium OA binding in solution by fluorescence, circular dichroism and isothermal titration calorimetry failed to confirm the sequence preference of OA, indicating instead a similar type of complex and comparable affinity of OA to all G/C binding sites. This discrepancy was resolved by kinetics analysis of the drug-DNA interaction: the dissociation rate significantly differed between SGCS, SGGS and SCGS sites (S stands for G or C), thereby explaining the disintegration of the complexes during EMSA. The functional relevance of the revealed differential kinetics of OA-DNA interaction was demonstrated in an in vitro transcription assay. These findings emphasize the crucial role of kinetics in the mechanism of OA action and provide an important approach to the screening of new drug candidates.
Topics: Circular Dichroism; CpG Islands; DNA; Kinetics; Olivomycins; Spectrometry, Fluorescence
PubMed: 32722584
DOI: 10.3390/ijms21155299 -
Cytometry Feb 1995It is shown by means of flow cytometry that during several seconds after cell membrane damage by a non-ionic detergent in physiologically relevant buffer solution, the...
It is shown by means of flow cytometry that during several seconds after cell membrane damage by a non-ionic detergent in physiologically relevant buffer solution, the chromatin of mouse thymocyte nuclei undergoes a drastic decondensation, which is revealed by a sharp increase of binding of DNA-specific fluorochromes (olivomycin or propidium iodide) and of DNA accessibility to DNAse I digestion. A similar change is observed in dead cells. Roughly half of this decondensation can be prevented by lowering the pH of the outside medium to the level known to be inside the cells; the other half remains thus far unexplained (divalent cations and the difference between small anion species seem not to be involved). The approach is based on a novel observation that fixation by formaldehyde conserves chromatin structure before the action of detergent. Flow cytometric assay is proposed for monitoring these condensation/decondensation events in media of different composition. In addition, a new approach to viable/dead cell determination, which has the advantage of immediately fixing the cell state and preserving it for a reasonably long time, is proposed.
Topics: Animals; Cell Membrane; Chromatin; DNA; Deoxyribonuclease I; Flow Cytometry; In Vitro Techniques; Male; Mice; Mice, Inbred C57BL; Octoxynol; Olivomycins; Propidium; Thymus Gland
PubMed: 7743898
DOI: 10.1002/cyto.990190214 -
PloS One 2018The current model of binding of the antitumor antibiotic olivomycin A (1) to GC-rich DNA regions presumes that coordination of the magnesium divalent cation with drug...
The current model of binding of the antitumor antibiotic olivomycin A (1) to GC-rich DNA regions presumes that coordination of the magnesium divalent cation with drug dimers is necessary for binding of 1 into the minor groove of the DNA duplex. Previously we have synthesized the derivatives of 1 termed 'short acid' (2) and its N,N-dimethylaminoethylamide (3). The latter compound demonstrated an improved tolerance in vivo compared to 1 and good therapeutic potency in animal models. We herein report that compound 3 is able to form stable complexes with DNA in the absence of Mg2+, in striking contrast to 1 whose binding to the DNA absolutely requires Mg2+. The mode of binding of 3 to DNA is similar in the presence or absence of Mg2+ as determined by circular dichroism. The affinity to DNA of 3 in Mg2+-free solution was similar to that of 1 or 3 in the presence of Mg2+ at low ionic strength. Non-electrostatic contributions to total free energy of binding of 1 and 3 to DNA were comparable for Mg2+-free complexes. Our data strongly suggest that electrostatic interaction of the positively charged 3 can compensate for the absence of divalent ions in complexes with DNA. This new property of the olivomycin A derivative expands the mechanistic knowledge of the modes of interaction with DNA of small molecular weight drug candidates.
Topics: Binding Sites; Cations, Divalent; Circular Dichroism; DNA; Electrophoresis, Agar Gel; Olivomycins; Spectrometry, Fluorescence; Static Electricity
PubMed: 29420558
DOI: 10.1371/journal.pone.0191923 -
Journal of Inorganic Biochemistry Sep 2020Twenty-four novel organometallic osmium(II) phenylazopyridine (AZPY) complexes have been synthesised and characterised; [Os(η-arene)(5-RO-AZPY)X]Y, where...
Twenty-four novel organometallic osmium(II) phenylazopyridine (AZPY) complexes have been synthesised and characterised; [Os(η-arene)(5-RO-AZPY)X]Y, where arene = p-cym or bip, AZPY is functionalized with an alkoxyl (O-R, R = Me, Et, Pr, Pr, Bu) or glycolic (O-{CHCHO}R*, n = 1-4, R* = H, Me, or Et) substituent on the pyridyl ring para to the azo-bond, X is a monodentate halido ligand (Cl, Br or I), and Y is a counter-anion (PF, CFSO or IO). X-ray crystal structures of two complexes confirmed their 'half-sandwich' structures. Aqueous solubility depended on X, the AZPY substituents, arene, and Y. Iodido complexes are highly stable in water (X = I ⋙ Br > Cl), and exhibit the highest antiproliferative activity against A2780 (ovarian), MCF-7 (breast), SUNE1 (nasopharyngeal), and OE19 (oesophageal) cancer cells, some attaining nanomolar potency and good cancer-cell selectivity. Their activity and distinctive mechanism of action is discussed in relation to hydrophobicity (RP-HPLC capacity factor and Log P), cellular accumulation, electrochemical reduction (activation of azo bond), cell cycle analysis, apoptosis and induction of reactive oxygen species (ROS). Two complexes show ca. 4× higher activity than cisplatin in the National Cancer Institute (NCI) 60-cell line five-dose screen. The COMPARE algorithm of their datasets reveals a strong correlation with one another, as well as anticancer agents olivomycin, phyllanthoside, bouvardin and gamitrinib, but only a weak correlation with cisplatin, indicative of a different mechanism of action.
Topics: Antineoplastic Agents; Azo Compounds; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Coordination Complexes; Drug Screening Assays, Antitumor; Ethers; Humans; Molecular Structure; Osmium; Pyridines; Reactive Oxygen Species; Structure-Activity Relationship
PubMed: 32771772
DOI: 10.1016/j.jinorgbio.2020.111154 -
3 Biotech Dec 2019We isolated an actinobacterium, sp. strain SP 85 from the marine sponge Polyphasic identification of the microorganism showed that the strain SP 85 had high 16S rRNA...
We isolated an actinobacterium, sp. strain SP 85 from the marine sponge Polyphasic identification of the microorganism showed that the strain SP 85 had high 16S rRNA gene similarity (99%) with strain NBRC 12805, while some physiological and biochemical differences were observed. A cytotoxic compound, was isolated from the active culture extract of the strain SP 85 by bioassay-guided purification over silica gel column chromatography, preparative TLC, and HPLC. The structure elucidation based on the spectroscopic analysis, including UV, ESI-MS, and C NMR data revealed that compound is an analog of anti-tumor drug, "olivomycin A". The compound showed high cytotoxic activity against three human cancer cell lines, including SW480, HepG2, and MCF7 with IC values of 16, 93, and 78 nM, respectively. exhibited significantly (2-10 times) higher cytotoxicity against the tumor cell lines in comparison with HUVECs as the normal cell line, which also induced apoptosis in the tested cancerous cell line. This is the first report on the production of an "olivomycin A" derivative by a sponge-associated , showing the great potential of sponge-associated actinobacteria in producing cytotoxic natural products.
PubMed: 31750037
DOI: 10.1007/s13205-019-1964-5 -
The Journal of Antibiotics Jan 1988Detailed studies on the 13C and 1H NMR spectra of chromomycins A2 and A3, olivomycins A and B, and their derivatives clarified the assignment of many signals which had...
Detailed studies on the 13C and 1H NMR spectra of chromomycins A2 and A3, olivomycins A and B, and their derivatives clarified the assignment of many signals which had been unassigned or erroneously reported in the literatures. The revised assignments for chromomycin A3 and olivomycin A include the assignment of a key 13C signal used to discuss the saccharide linkage in question. Structure analyses based on the revised assignments support the alpha,1----3-bond between components of the disaccharide moiety in the molecules. Some general information useful for structure analysis of saccharides is also reported.
Topics: Chromomycins; Magnetic Resonance Spectroscopy; Olivomycins
PubMed: 3346193
DOI: 10.7164/antibiotics.41.53 -
The Journal of Antibiotics Jan 1988Structure determination using NMR spectroscopy of new aureolic acid analogues, demethylchromomycins A2 and A3 and demethylolivomycins A and B produced by Streptomyces...
Structure determination using NMR spectroscopy of new aureolic acid analogues, demethylchromomycins A2 and A3 and demethylolivomycins A and B produced by Streptomyces aburaviensis PA-39856, is described.
Topics: Antibiotics, Antineoplastic; Chemical Phenomena; Chemistry; Chromomycins; Magnetic Resonance Spectroscopy; Olivomycins
PubMed: 3346194
DOI: 10.7164/antibiotics.41.68