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1.
Appl Environ Microbiol ; 87(24): e0138021, 2021 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-34586912

RESUMO

The production of specialized metabolites by Streptomyces bacteria is usually temporally regulated. This regulation is complex and frequently involves both global and pathway-specific mechanisms. Streptomyces ambofaciens ATCC23877 produces several specialized metabolites, including spiramycins, stambomycins, kinamycins and congocidine. The production of the first three molecules has been shown to be controlled by one or several cluster-situated transcriptional regulators. However, nothing is known regarding the regulation of congocidine biosynthesis. Congocidine (netropsin) belongs to the family of pyrrolamide metabolites, which also includes distamycin and anthelvencins. Most pyrrolamides bind into the minor groove of DNA, specifically in A/T-rich regions, which gives them numerous biological activities, such as antimicrobial and antitumoral activities. We previously reported the characterization of the pyrrolamide biosynthetic gene clusters of congocidine (cgc) in S. ambofaciens ATCC23877, distamycin (dst) in Streptomyces netropsis DSM40846, and anthelvencins (ant) in Streptomyces venezuelae ATCC14583. The three gene clusters contain a gene encoding a putative transcriptional regulator, cgc1, dst1, and ant1, respectively. Cgc1, Dst1, and Ant1 present a high percentage of amino acid sequence similarity. We demonstrate here that Cgc1, an atypical orphan response regulator, activates the transcription of all cgc genes in the stationary phase of S. ambofaciens growth. We also show that the cgc cluster is constituted of eight main transcriptional units. Finally, we show that congocidine induces the expression of the transcriptional regulator Cgc1 and of the operon containing the resistance genes (cgc20 and cgc21, coding for an ABC transporter), and propose a model for the transcriptional regulation of the cgc gene cluster. IMPORTANCE Understanding the mechanisms of regulation of specialized metabolite production can have important implications both at the level of specialized metabolism study (expression of silent gene clusters) and at the biotechnological level (increase of the production of a metabolite of interest). We report here a study on the regulation of the biosynthesis of a metabolite from the pyrrolamide family, congocidine. We show that congocidine biosynthesis and resistance are controlled by Cgc1, a cluster-situated regulator. As the gene clusters directing the biosynthesis of the pyrrolamides distamycin and anthelvencin encode a homolog of Cgc1, our findings may be relevant for the biosynthesis of other pyrrolamides. In addition, our results reveal a new type of feed-forward induction mechanism, in which congocidine induces its own biosynthesis through the induction of the transcription of cgc1.


Assuntos
Regulação Bacteriana da Expressão Gênica , Netropsina , Streptomyces , Distamicinas , Genes Bacterianos , Família Multigênica , Netropsina/biossíntese , Streptomyces/genética , Streptomyces/metabolismo
2.
Molecules ; 26(17)2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34500619

RESUMO

The recognition of specific DNA sequences in processes such as transcription is associated with a cooperative binding of proteins. Some transcription regulation mechanisms involve additional proteins that can influence the binding cooperativity by acting as corepressors or coactivators. In a conditional cooperativity mechanism, the same protein can induce binding cooperativity at one concentration and inhibit it at another. Here, we use calorimetric (ITC) and spectroscopic (UV, CD) experiments to show that such conditional cooperativity can also be achieved by the small DNA-directed oligopeptides distamycin and netropsin. Using a global thermodynamic analysis of the observed binding and (un)folding processes, we calculate the phase diagrams for this system, which show that distamycin binding cooperativity is more pronounced at lower temperatures and can be first induced and then reduced by increasing the netropsin or/and Na+ ion concentration. A molecular interpretation of this phenomenon is suggested.


Assuntos
DNA/metabolismo , Oligopeptídeos/metabolismo , Distamicinas/metabolismo , Netropsina/metabolismo , Ligação Proteica/genética , Ligação Proteica/fisiologia , Sódio/metabolismo , Termodinâmica , Transcrição Gênica/genética
3.
Arch Biochem Biophys ; 701: 108797, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33607110

RESUMO

Human telomerase that activates within cancer cells has a telomeric sequence at the 3' end. Each factor that stabilizes the G-quadruplex in guanine-rich telomeric sequences can inhibit the regular telomerase activity. Therefore, the telomeric G-quadruplex is known as a promising target in cancer treatment. In this work, we studied the binding of positively charged distamycin A and its uncharged derivative to the G-quadruplex in a solution environment by Molecular Dynamics (MD) simulation. The binding mechanism and subtle conformational changes were investigated as a result of the ligand attachment. Moreover, binding free energy and clustering analysis describe the stability and flexibility of G-quadruplexes upon ligand binding. Structural analyses displayed that the favorable binding of both ligands imposes significant stability and rigidity in G-quadruplex conformation compared to free G-quadruplex, especially charged distamycin. Hydration pattern and ion distribution were different for free G-quadruplex and both of the ligand complexes. Energy decomposition reveals the electrostatic effect on the stability of G-quadruplex. The radial distribution function displayed the solvent shell and ion moving away from the groove. The hydrogen bond played an essential role in the binding of both ligands, especially for the charged derivative. van der Waals interaction is the only factor that is more important in binding uncharged distamycin into G-quadruplex than the charged one. The calculated ΔGbind showed the stability of both ligands within grooves and good agreement with the experimental binding free energy data. Finally, the results suggest that ligand modification improves the binding mode toward stabilizing G-quadruplexes.


Assuntos
Antineoplásicos/química , Distamicinas/química , Quadruplex G , Simulação de Dinâmica Molecular , Telômero/química , Humanos
4.
Eur J Med Chem ; 195: 112202, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32302880

RESUMO

We have designed and synthesized anthraquinone containing compounds which have oligopyrrole side chains of varying lengths. These compounds stabilized the G-quadruplex DNA formed in the promoter regions of c-MYC oncogenes selectively over the duplex DNA. These observations were recorded using UV-vis spectroscopic titrations, fluorescence measurements and circular dichroism (CD) spectral titrations. The potency of the compounds to stabilize the G4 DNA has been shown from the thermal denaturation experiments. The compound interacts with c-MYC G-quadruplex DNA through stacking mode as obtained from ethidium bromide displacement assay, cyclic voltammetric titration, and docking experiments. Molecular modeling studies suggested that the stacking of the anthraquinone moiety over the G-tetrad of the G4 structures are responsible for the stability of such quadruplex secondary structure. Furthermore, polymerase stop assay also supported the formation of stable G4 structures in the presence of the above-mentioned compounds. The compounds have shown selective cancer cell (HeLa and HEK293T) cytotoxicity over normal cells (NIH3T3 and HDFa) under in vitro conditions as determined from MTT based cell viability assay. Apoptosis was found to be the mechanistic pathway underlying the cancer cell cytotoxicity as obtained from Annexin V-FITC and PI dual staining assay which was further substantiated by nuclear morphological changes as observed by AO/EB dual staining assay. Cellular morphological changes, as well as nuclear condensation and fragmentation upon treatment with these compounds, were observed under bright field and confocal microscopy.


Assuntos
Antracenos/química , Dimerização , Distamicinas/química , Distamicinas/farmacologia , Quadruplex G/efeitos dos fármacos , Regiões Promotoras Genéticas/genética , Proteínas Proto-Oncogênicas c-myc/genética , Antineoplásicos/química , Antineoplásicos/farmacologia , DNA/química , DNA/genética , Desenho de Fármacos , Modelos Moleculares
5.
Eur J Med Chem ; 189: 112043, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31978782

RESUMO

Polyamides-based compounds related to the Streptomycetal distamycin and netropsin are potent cytostatic molecules that bind to AT-rich regions of the minor groove of the DNA, hence interfering with DNA replication and transcription. Recently, derivatives belonging to this scaffold have been reported to halt the proliferation of deadly African trypanosomes by different and unrelated mechanisms. Here we describe the synthesis and preliminary characterization of the anti-trypanosomal mode of action of new potent and selective distamycin analogues. Two tri-heterocyclic derivatives containing a central N-methyl pyrrole ring (16 and 17) displayed high activity (EC50 < 20 nM) and selectivity (selectivity index >5000 with respect to mammalian macrophages) against the infective form of T. brucei. Both compounds caused cell cycle arrest by blocking the replication of the mitochondrial DNA but without affecting its integrity. This mode of action clearly differs from that reported for classical minor groove binder (MGB) drugs, which induce the degradation of the mitochondrial DNA. In line with this, in vitro assays suggest that 16 and 17 have a comparatively lower affinity for different template DNAs than the MGB drug diminazene. Therapeutic efficacy studies and stability assays suggest that the pharmacological properties of the hits should be optimized. The compounds can be rated as excellent scaffolds for the design of highly potent and selective anti-T. brucei agents.


Assuntos
Ciclo Celular/efeitos dos fármacos , Distamicinas/química , Macrófagos/efeitos dos fármacos , Tiazóis/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma/efeitos dos fármacos , Tripanossomíase Africana/tratamento farmacológico , Animais , Feminino , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Tiazóis/química , Tripanossomicidas/química , Trypanosoma/parasitologia , Tripanossomíase Africana/parasitologia
6.
J Comput Chem ; 41(10): 986-999, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-31930547

RESUMO

Alchemically derived free energies are artifacted when the perturbed moiety has a nonzero net charge. The source of the artifacts lies in the effective treatment of the electrostatic interactions within and between the perturbed atoms and remaining (partial) charges in the simulated system. To treat the electrostatic interactions effectively, lattice-summation (LS) methods or cutoff schemes in combination with a reaction-field contribution are usually employed. Both methods render the charging component of the calculated free energies sensitive to essential parameters of the system like the cutoff radius or the box side lengths. Here, we discuss the results of three previously published studies of ligand binding. These studies presented estimates of binding free energies that were artifacted due to the charged nature of the ligands. We show that the size of the artifacts can be efficiently calculated and raw simulation data can be corrected. We compare the corrected results with experimental estimates and nonartifacted estimates from path-sampling methods. Although the employed correction scheme involves computationally demanding continuum-electrostatics calculations, we show that the correction estimate can be deduced from a small sample of configurations rather than from the entire ensemble. This observation makes the calculations of correction terms feasible for complex biological systems. To show the general applicability of the proposed procedure, we also present results where the correction scheme was used to correct independent free energies obtained from simulations employing a cutoff scheme or LS electrostatics. In this work, we give practical guidelines on how to apply the appropriate corrections easily.


Assuntos
Eletricidade Estática , Artefatos , Sítios de Ligação , DNA/química , Distamicinas/química , Ligantes , Simulação de Dinâmica Molecular , Netropsina/química , Solventes/química , Termodinâmica , Inibidores da Tripsina/química
7.
Acta Biochim Biophys Sin (Shanghai) ; 52(1): 91-96, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31833535

RESUMO

Distamycin (DST) is a well-characterized DNA minor groove binder with antivirus activity and antitumor potency. Two separate gene clusters (a 28-kb cluster and a 7-kb cluster) have recently been identified to coordinately encode the biosynthetic machinery of DST in Streptomyces netropsis. Here we report a gene cassette, which is linked to the aforementioned smaller dst gene cluster and plays an important role in the self-resistance to DST in S. netropsis. This cassette consists of three uncharacterized genes that might be implicated in DNA replication/repair. Knockout of the cassette led to the decrease in the production of DST, while heterologous expression of part of the cassette in S. lividans made it become resistant to both DST and mitomycin C, another DNA-binding agent. More interestingly, homologs of these three genes were found in genomes of other actinomyces that produce DNA-binding antibiotics, suggesting that a novel common mechanism in addition to pumping may enable these strains to resist the cytotoxic metabolites they produced.


Assuntos
Antibacterianos/farmacologia , Reparo do DNA/genética , Replicação do DNA/genética , Distamicinas/farmacologia , Farmacorresistência Bacteriana/genética , Genes Bacterianos/genética , Streptomyces/genética , Antibacterianos/biossíntese , Células Cultivadas , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/farmacologia , Distamicinas/biossíntese , Escherichia coli/genética , Técnicas de Inativação de Genes , Mitomicina/farmacologia , Família Multigênica/genética , Streptomyces/efeitos dos fármacos , Streptomyces lividans/efeitos dos fármacos
8.
Mini Rev Med Chem ; 19(2): 98-113, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30626311

RESUMO

The DNA as the depository of genetic information is a natural target for chemotherapy. A lot of anticancer and antimicrobial agents derive their biological activity from their selective interaction with DNA in the minor groove and from their ability to interfere with biological processes such as enzyme catalysis, replication and transcription. The discovery of the details of minor groove binding drugs, such as netropsin and distamycin A, oligoamides built of 4-amino-1-methylpyrrole-2-carboxylic acid residues, allowed to develop various DNA sequence-reading molecules, named lexitropsins, capable of interacting with DNA precisely, strongly and with a high specificity, and at the same time exhibiting significant cytotoxic potential. Among such compounds, lexitropsins built of carbocyclic sixmembered aromatic rings occupy a quite prominent place in drug research. This work is an attempt to present current findings in the study of carbocyclic lexitropins, their structures, syntheses and biological investigations such as DNA-binding and antiproliferative activity.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Distamicinas/química , Distamicinas/farmacologia , Desenho de Fármacos , Netropsina/análogos & derivados , Netropsina/farmacologia , Ácidos Carbocíclicos/síntese química , Ácidos Carbocíclicos/química , Ácidos Carbocíclicos/farmacologia , Animais , Antibacterianos/síntese química , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , DNA/química , DNA/metabolismo , Distamicinas/síntese química , Humanos , Neoplasias/tratamento farmacológico , Netropsina/síntese química
9.
Biochimie ; 157: 149-157, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30481539

RESUMO

PA1 (dIm-PyPyßPyPyPy-γ-PyPyßPyPyPyPyß-Ta) is a large (14-ring) hairpin polyamide that was designed to recognize the DNA sequence 5'-W2GW7-3', where W is either A or T. As is common among the smaller 6-8-ring hairpin polyamides (PAs), it binds its target recognition sequence with low nM affinity. However, in addition to its large size, it is distinct from these more extensively characterized PAs in its high tolerance for mismatches and antiviral properties. In ongoing attempts to understand the basis for these distinctions, we conducted thermodynamics studies of PA1-DNA interactions. The temperature dependence of binding affinity was measured using TAMRA-labeled hairpin DNAs containing a single target sequence. PA1 binding to either an ATAT/TATA or an AAAA/TTTT pattern is consistently entropically driven. This is in contrast to the A/T pattern-dependent driving forces for DNA binding by netropsin, distamycin, and smaller hairpin polyamides. Analysis of the salt dependence of PA1-DNA binding reveals that within experimental error, there is no dependence on ionic strength, indicating that the polyelectrolyte effect does not contribute to PA1-DNA binding energetics. This is similar to that observed for smaller PAs. PA1-DNA recognition sequence binding stoichiometries were determined at both nM (fluorescence) and µM (circular dichroism) concentrations. With all sequences and under both conditions, multiple PA1 molecules bind the small DNA hairpin that contains only a single recognition sequence. Implications for these observations are discussed.


Assuntos
Antivirais/química , DNA/química , Distamicinas/química , Netropsina/química , Nylons/química , Termodinâmica
10.
Biochemistry (Mosc) ; 83(10): 1231-1244, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30472960

RESUMO

We studied the thermodynamics of melting of isolated rat liver nuclei with different degrees of chromatin condensation determined by the concentration of polyamines (PA) and the solution ionic strength, as well as the effect of the antibiotic distamycin A (DM) on melting. Differential scanning calorimetry (DSC) profiles of nuclear preparations contained three peaks that reflected melting of three main chromatin domains. The number of peaks did not depend on the degree of condensation; however, nuclei with more condensed chromatin had a higher total enthalpy. DM stabilized peaks II and III corresponding to the melting of relaxed and topologically strained DNA, respectively, but destabilized peak I corresponding to the melting of nucleosome core histones. At the saturating concentration (DM/DNA molar ratio = 0.1), DM increased Tm of peaks II and III by ~5°C and decreased Tm of peak I by ~2.5°C. Based on the dependence of ΔH on DM concentration, we established that at low DM/DNA ratio (≤0.03), when DM interacted predominantly with AT-rich DNA regions, the enthalpy of peak II decreased in parallel with the increase in the enthalpy of peak III, which indicated that DM induces structural transitions in the nuclear chromatin associated with the increase in torsional stress in DNA. An increase in free energy under saturation conditions was equal to the change in the free energy of DM interaction with DNA. However, the increase in the enthalpy of melting of the nuclei in the presence of DM was much greater than the enthalpy of titration of nuclei with DM. This indicates a significant increase in the strength of interaction between the two DNA strands apparently due, among other things, to changes in the torsional stress of DNA in the nuclei. Titration of the nuclei with increasing PA concentrations resulted in the decrease in the number of DM-binding sites and the non-monotonous dependence of the enthalpy and entropy contribution to the binding free energy on the PA content. We suggested that the observed differences in the thermodynamic parameters were due to the different width of the minor groove in the nuclear chromatin DNA, which depends on PA concentration.


Assuntos
Núcleo Celular/metabolismo , Cromatina/metabolismo , Distamicinas/metabolismo , Fígado/metabolismo , Poliaminas/metabolismo , Animais , Sítios de Ligação , Varredura Diferencial de Calorimetria , Cromatina/química , DNA/química , DNA/metabolismo , Distamicinas/química , Feminino , Microscopia Eletrônica , Poliaminas/química , Ratos , Termodinâmica , Temperatura de Transição
11.
Nucleic Acids Res ; 46(11): 5355-5365, 2018 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-29762718

RESUMO

The structural differences among different G-quadruplexes provide an opportunity for site-specific targeting of a particular G-quadruplex structure. However, majority of G-quadruplex ligands described thus far show little selectivity among different G-quadruplexes. In this work, we delineate the design and synthesis of a crescent-shaped thiazole peptide that preferentially stabilizes c-MYC quadruplex over other promoter G-quadruplexes and inhibits c-MYC oncogene expression. Biophysical analysis such as Förster resonance energy transfer (FRET) melting and fluorescence spectroscopy show that the thiazole peptide TH3 can selectively interact with the c-MYC G-quadruplex over other investigated G-quadruplexes and duplex DNA. NMR spectroscopy reveals that peptide TH3 binds to the terminal G-quartets and capping regions present in the 5'- and 3'-ends of c-MYC G-quadruplex with a 2:1 stoichiometry; whereas structurally related distamycin A is reported to interact with quadruplex structures via groove binding and end stacking modes with 4:1 stoichiometry. Importantly, qRT-PCR, western blot and dual luciferase reporter assay show that TH3 downregulates c-MYC expression by stabilizing the c-MYC G-quadruplex in cancer cells. Moreover, TH3 localizes within the nucleus of cancer cells and exhibits antiproliferative activities by inducing S phase cell cycle arrest and apoptosis.


Assuntos
Quadruplex G/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Neoplasias/patologia , Peptídeos/metabolismo , Proteínas Proto-Oncogênicas c-myc/biossíntese , Tiazóis/metabolismo , Células A549 , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Distamicinas/química , Regulação para Baixo , Células HeLa , Humanos , Modelos Moleculares , Pontos de Checagem da Fase S do Ciclo Celular/efeitos dos fármacos , Relação Estrutura-Atividade
12.
Eur J Med Chem ; 136: 561-572, 2017 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-28544982

RESUMO

This study details the synthesis and biological evaluation of a collection of 19 structurally related Minor Groove Binders (MGBs), derived from the natural product distamycin, which were designed to probe antifungal and antimycobacterial activity. From this initial set, we report several MGBs that are worth more detailed investigation and optimisation. MGB-4, MGB-317 and MGB-325 have promising MIC80s of 2, 4 and 0.25 µg/mL, respectively, against the fungus C. neoformans.MGB-353 and MGB-354 have MIC99s of 3.1 µM against the mycobacterium M. tuberculosis. The selectivity and activity of these compounds is related to their physicochemical properties and the cell wall/membrane characteristics of the infective agents.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Produtos Biológicos/farmacologia , Cryptococcus neoformans/efeitos dos fármacos , Distamicinas/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Antifúngicos/síntese química , Antifúngicos/química , Produtos Biológicos/síntese química , Produtos Biológicos/química , Distamicinas/síntese química , Distamicinas/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade
13.
Pharm Biol ; 55(1): 687-690, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27982735

RESUMO

CONTEXT: Natural oligopeptide antibiotic distamycin A (Dst) biosynthesized by Streptomyces distallicus is traditionally used in medical practice as an anti-inflammatory and antitumour drug. OBJECTIVE: Dst was investigated for its effect on the structural components of native chromatin directly within isolated rat liver nuclei in the presence of physiologically significant cations (magnesium or spermine and spermidine). MATERIALS AND METHODS: Differential scanning calorimetry (DSC) was used to study the Dst action at molar ratio Dst/DNA = 0.1 and 0.15 mM Dst on the melting profile of nuclei suspension in different conditions. RESULTS: Results showed that the thermodynamic parameters of control nuclei in the presence of polyamines or Mg2+ were different. The incubation of nuclei with Dst raised transition temperatures of relaxed (peak II) and topologically constrained DNA (peak III) by 6-8 °C and decreased by 2-4 °C that of core-histones (peak I). The total excess transition enthalpy (ΔHexc) in buffer with polyamines (24.7 kJ/mol DNA nucleotides) increased by1.5 times versus control but in buffer with Mg2+, the value of ΔHexc (35.8 kJ/mol DNA nucleotides) remained unchanged. CONCLUSIONS: The association of Dst with chromatin in the nucleus weakens histone-DNA contacts and causes additional strengthening of interaction between two complementary DNA chains. Our results contribute towards validation of DSC to test drug ability to modulate chromatin structure in the physiological environment and to clarify the mechanism of these modulations.


Assuntos
Antibacterianos/metabolismo , Varredura Diferencial de Calorimetria , Núcleo Celular/metabolismo , Cromatina/metabolismo , DNA/metabolismo , Distamicinas/metabolismo , Histonas/metabolismo , Fígado/metabolismo , Animais , Antibacterianos/farmacologia , Núcleo Celular/efeitos dos fármacos , Cromatina/química , Cromatina/efeitos dos fármacos , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , DNA/química , Distamicinas/farmacologia , Feminino , Histonas/química , Fígado/efeitos dos fármacos , Magnésio/metabolismo , Conformação de Ácido Nucleico , Ligação Proteica , Ratos , Espermidina/metabolismo , Espermina/metabolismo , Temperatura
14.
Eur J Med Chem ; 126: 776-788, 2017 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-27951486

RESUMO

Distamycin, a natural polyamide containing three heterocycle rings with a polar end, has inspired several groups to prepare synthetic analogues, which proved to have anti-trypanosomal and anti-tumoral activity. We describe the synthesis of bi and tri thiazoles amides that harbor different substitutions at their ends and the evaluation of their anti-Trypanosoma brucei activity. The most active compound 10b showed better biological activity (EC50 310 nM and selectivity index 16) than the control drug nifurtimox (EC50 15 µM and selectivity index 10). Studies on the mode of action show that the parasiticidal activity of 10b originates from disruption of lysosomal homeostasis, which is followed by release of redox active iron, an increase in oxidizing species and collapse of cell membrane integrity. In this respect, our study suggests that non-charged lipophylic distamycins destabilize cell membranes.


Assuntos
Distamicinas/farmacologia , Tripanossomicidas/química , Trypanosoma/efeitos dos fármacos , África , Antineoplásicos/química , Antineoplásicos/farmacologia , Membrana Celular/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Tiazóis/síntese química , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos
15.
Acta Chim Slov ; 63(4): 689-704, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-28004090

RESUMO

The synthesis and biological activity of a variety of analogues to the naturally occurring antibacterial and antifungal Distamycin A were explored by a number of authors. These compounds were subject to a large array of assays. Some of these compounds showed high activity against a range of Gram-positive, Gram-negative bacteria as well as fungi. To explore the anti-parasitic activity of this class of compounds, specific modifications had to be made. A number of these compounds proved to be active against Trypanosoma brucei. The binding of a number of these compounds to short sequences of DNA were also examined using footprinting assays as well as NMR spectroscopy. Computer modelling was employed on selected compounds to understand the way these compounds bind to specific DNA sequences. A large number of variations were made to the standard structure of Distamycin. These changes involved the replacement of the pyrrole moieties as well as the head and tail groups with a number of heterocyclic compounds. Some of these minor groove binders (MGBs) were also investigated for their capability for the treatment of cancer and in particular lung cancer.


Assuntos
DNA/metabolismo , Distamicinas/metabolismo , Animais , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Simulação por Computador , DNA/química , Pegada de DNA , Distamicinas/química , Distamicinas/farmacologia , Humanos , Espectroscopia de Ressonância Magnética , Tripanossomicidas/química , Tripanossomicidas/metabolismo , Tripanossomicidas/farmacologia
16.
Bioorg Med Chem Lett ; 26(15): 3478-86, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27349332

RESUMO

A series of 47 structurally diverse MGBs, derived from the natural product distamycin, was evaluated for anti-lung cancer activity by screening against the melanoma cancer cell line B16-F10. Five compounds have been found to possess significant activity, more so than a standard therapy, Gemcitabine. Moreover, one compound has been found to have an activity around 70-fold that of Gemcitabine and has a favourable selectivity index of greater than 125. Furthermore, initial studies have revealed this compound to be metabolically stable and thus it represents a lead for further optimisation towards a novel treatment for lung cancer.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Produtos Biológicos/farmacologia , Desoxicitidina/análogos & derivados , Distamicinas/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Desoxicitidina/química , Desoxicitidina/isolamento & purificação , Desoxicitidina/farmacologia , Distamicinas/química , Distamicinas/isolamento & purificação , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Neoplasias Pulmonares/patologia , Estrutura Molecular , Relação Estrutura-Atividade , Gencitabina
17.
Dalton Trans ; 45(22): 9345-53, 2016 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-27186601

RESUMO

Minor groove binding distamycin like moieties were conjugated with core salens and the corresponding Fe(iii) and Co(ii) complexes were synthesized. Herein, we have shown efficient DNA minor groove binding specificities along with excellent DNA cleavage capacities with metallosalen conjugates. The metal complexes showed toxicity toward various cancer cells over normal cells with high specificity. Interestingly, the Co(ii) complexes exhibited greater activity than the Fe(iii) complexes in accordance with the stronger affinity of the former in the biophysical studies. Active DNA damage, and prominent nuclear condensation along with the release of cytochrome-c from the mitochondria unanimously showed that the metal complexes followed apoptotic pathways to induce cell death.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Cobalto/farmacologia , Complexos de Coordenação/farmacologia , Dano ao DNA , DNA/efeitos dos fármacos , Distamicinas/farmacologia , Compostos Férricos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Sobrevivência Celular/efeitos dos fármacos , Quelantes/farmacologia , Complexos de Coordenação/síntese química , DNA/biossíntese , Clivagem do DNA , Etilenodiaminas/farmacologia , Compostos Férricos/síntese química , Células HEK293 , Células HeLa , Humanos , Mitocôndrias/metabolismo
18.
Acta Pol Pharm ; 73(1): 47-53, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27008800

RESUMO

The evaluation of a new group of distamycin analogues 1-6 as potential minor groove binders for the treatment of cancer were investigated. The activity of the new compounds against several restriction enzymes was examined. The studied compounds did not block GC-rich sequences regions of DNA but inhibited catalytic action of endonucleases in AA, AT, TT and AG restriction sites. Determination of association constants using calf thymus DNA, T4 coliphage DNA, poly(dA-dT)2 and poly(dG-dC)2 have confirmed that the tested compounds bind within minor groove of B-DNA. All of the compounds demonstrated activity against DNA topoisomerases II at the concentration 10 µM, but they did not inhibit activity of topoisomerase I. The studied derivatives were evaluated in human MCF-7 breast cancer cells and showed antiproliferative and cytotoxic effects in the range of 81.70 µM and 200.00 µM.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Proliferação de Células/efeitos dos fármacos , Endonucleases/antagonistas & inibidores , Inibidores da Topoisomerase/farmacologia , Neoplasias da Mama/patologia , Distamicinas/farmacologia , Feminino , Humanos , Células MCF-7
19.
Int J Pharm ; 492(1-2): 120-6, 2015 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-26183332

RESUMO

Liposomes containing Distamycin A (DA) may be clinically useful in the treatment of ocular HSV infections, especially in acyclovir-resistant HSV keratitis. This study evaluated the in vitro and in vivo performance of a topical controlled release liposomal formulation containing DA (DA-Lipo) aimed at reducing the toxicity of the encapsulated active agent and improving drug uptake by ocular tissues. The bioavailability of DA in the tear fluid and the DA uptake into the cornea were increased after instillation of DA-Lipo in rabbits, reaching the DA corneal concentration corresponding to IC50 values against HSV without any sign of transcorneal permeation of drug. DA-Lipo was definitely less cytotoxic then plain DA in rabbit corneal epithelial cells. These results provide new insights into the correlation between the in vitro data and the drug kinetics following ocular applications of liposomal vesicles.


Assuntos
Antivirais/administração & dosagem , Distamicinas/administração & dosagem , Administração Oftálmica , Animais , Antivirais/farmacocinética , Humor Aquoso/metabolismo , Disponibilidade Biológica , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Córnea/metabolismo , Distamicinas/farmacocinética , Herpesvirus Humano 1/efeitos dos fármacos , Herpesvirus Humano 2/efeitos dos fármacos , Lipossomos , Masculino , Coelhos , Lágrimas/metabolismo , Células Vero
20.
Bioorg Med Chem ; 23(13): 3705-11, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-25921267

RESUMO

The alarming rise of extensively drug-resistant tuberculosis (XDR-TB) strains, compel the development of new molecules with novel modes of action to control this world health emergency. Distamycin analogues containing N-terminal biaryl-motifs 2(1-5)(1-7) were synthesised using a solution-phase approach and evaluated for their anti-mycobacterial activity and DNA-sequence selectivity. Thiophene dimer motif-containing polyamide 2(2,6) exhibited 10-fold higher inhibitory activity against Mycobacterium tuberculosis compared to distamycin and library member 2(5,7) showed high binding affinity for the 5'-ACATAT-3' sequence.


Assuntos
Antituberculosos/síntese química , DNA Bacteriano/antagonistas & inibidores , Distamicinas/síntese química , Nylons/síntese química , Bibliotecas de Moléculas Pequenas/síntese química , Antituberculosos/farmacologia , Sítios de Ligação , Técnicas de Química Combinatória , Pegada de DNA , DNA Bacteriano/química , Distamicinas/farmacologia , Ligantes , Testes de Sensibilidade Microbiana , Modelos Moleculares , Mycobacterium tuberculosis/química , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/crescimento & desenvolvimento , Nylons/farmacologia , Bibliotecas de Moléculas Pequenas/farmacologia , Relação Estrutura-Atividade , Tiofenos/química
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