RESUMO
Peptides are receiving significant attention in pharmaceutical sciences due to their applications as anti-inflammatory drugs; however, many aspects of their interactions and mechanisms at the molecular level are not well-known. This work explores the molecular structure of two peptides-(i) cysteine (Cys)-asparagine (Asn)-serine (Ser) (CNS) as a molecule in the gas phase and solvated in water in zwitterion form, and (ii) the crystal structure of the dipeptide serine-asparagine (SN), a reliable peptide indication whose experimental cell parameters are well known. A search was performed by means of atomistic calculations based on density functional theory (DFT). These calculations matched the experimental crystal structure of SN, validating the CNS results and useful for assignments of our experimental spectroscopic IR bands. Our calculations also explore the intercalation of CNS into the interlayer space of montmorillonite (MNT). Our quantum mechanical calculations show that the conformations of these peptides change significantly during intercalation into the confined interlayer space of MNT. This intercalation is energetically favorable, indicating that this process can be a useful preparation for therapeutic anti-inflammatory applications and showing high stability and controlled release processes.
Assuntos
Anti-Inflamatórios , Bentonita , Cisteína , Teoria da Densidade Funcional , Serina , Bentonita/química , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Cisteína/química , Serina/química , Asparagina/química , Modelos Moleculares , Peptídeos/química , Substâncias Intercalantes/químicaRESUMO
Anticancer drugs inhibit DNA replication by intercalating between DNA base pairs, forming covalent bonds with nucleotide bases, or binding to the DNA groove. To develop safer drugs, novel molecular structures with alternative binding mechanisms are essential. Stable boron hydrides offer a promising alternative for cancer therapy, opening up additional options like boron neutron capture therapy based on 10B and thermal neutron beams or proton boron fusion therapy using 11B and proton beams. These therapies are more efficient when the boron compound is ideally located inside cancer cells, particularly in the nucleus. Current cancer treatments often utilize small, polycyclic, aromatic, planar molecules that intercalate between ds-DNA base pairs, requiring only a spacing of approximately 0.34 nm. In this paper, we demonstrate another type of intercalation. Notably, [3,3'-Fe(1,2-C2B9H11)2]-, ([o-FESAN]-), a compact 3D molecule measuring 1.1 nm × 0.6 nm, can as well intercalate by strong non-bonding interactions preferentially with guanine. Unlike known intercalators, which are positive or neutral, [o-FESAN]- is a negative species and when an [o-FESAN]- molecule approaches the negatively charged DNA phosphate chain an anion-anion interaction consistently anti-electrostatic via Ccluster-Hâ¯O-P bonds occurs. Then, when more molecules approach, an elongated outstandingly self-assembled structure of [o-FESAN]--[o-FESAN]- forms moving anions towards the interthread region to interact with base pairs and form aggregates of four [o-FESAN]- anions per base pair. These aggregates, in this environment, are generated by Ccluster-Hâ¯O-C, N-Hâ¯H-B and Ccluster-Hâ¯H-B interactions. The ferrabis(dicarbollide) boron-rich small molecules not only effectively penetrate the nucleus but also intercalate with ds-DNA, making them promising for cancer treatment. This amphiphilic anionic molecule, used as a carrier-free drug, can enhance radiotherapy in a multimodal perspective, providing healthcare professionals with improved tools for cancer treatment. This work demonstrates these findings with a plethora of techniques.
Assuntos
Ânions , Antineoplásicos , DNA , Substâncias Intercalantes , Antineoplásicos/química , Antineoplásicos/farmacologia , DNA/química , Substâncias Intercalantes/química , Substâncias Intercalantes/farmacologia , Humanos , Ânions/química , Compostos de Boro/química , Compostos de Boro/farmacologia , Estrutura MolecularRESUMO
The DNA binding and cellular uptake of the lambda enantiomer of two bis-tetraazaphenanthrene (TAP) Ru(II) polypyridyl complexes containing either a linear dppn (1) or a hooked bdppz (2) benzodipyridophenazine ligand are reported, and the role of different charge-transfer states of the structural isomers in the photo-oxidation of guanine is explored. Both complexes possess characteristic metal-to-ligand charge-transfer (MLCT) bands between 400 and 500 nm and emission at ca. 630 nm in an aerated aqueous solution. Transient visible absorption (TrA) spectroscopy reveals that 400 nm excitation of 1 yields a dppn-based metal-to-ligand charge-transfer (MLCT) state, which in turn populates a dppn intraligand (3IL) state. In contrast, photoexcitation of 2 results in an MLCT state on the TAP ligand and not the intercalating bdppz ligand. Both 1 and 2 bind strongly to double-stranded guanine-rich DNA with a loss of emission. Combined TrA and time-resolved infrared (TRIR) spectroscopy confirms formation of the guanine radical cation when 2 is bound to the d(G5C5)2 duplex, which is not the case when 1 is bound to the same duplex and indicates a different mechanism of action in DNA. Utilizing the long-lived triplet excited lifetime, we show good uptake and localization of 2 in live cells as well as isolated chromosomes. The observed shortening of the excited-state lifetime of 2 when internalized in cell chromosomes is consistent with DNA binding and luminescent quenching due to guanine photo-oxidation.
Assuntos
DNA , Guanina , Substâncias Intercalantes , Rutênio , DNA/química , DNA/metabolismo , Guanina/química , Rutênio/química , Ligantes , Substâncias Intercalantes/química , Humanos , Isomerismo , Processos Fotoquímicos , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/metabolismo , Piridinas/química , Complexos de Coordenação/química , Complexos de Coordenação/metabolismo , Estrutura Molecular , Células HeLaRESUMO
Targeting inter-duplex junctions in catenated DNA with bidirectional bis-intercalators is a potential strategy for enhancing anticancer effects. In this study, we used d(CGTATACG)2, which forms a tetraplex base-pair junction that resembles the DNA-DNA contact structure, as a model target for two alkyl-linked diaminoacridine bis-intercalators, DA4 and DA5. Cross-linking of the junction site by the bis-intercalators induced substantial structural changes in the DNA, transforming it from a B-form helical end-to-end junction to an over-wounded side-by-side inter-duplex conformation with A-DNA characteristics and curvature. These structural perturbations facilitated the angled intercalation of DA4 and DA5 with propeller geometry into two adjacent duplexes. The addition of a single carbon to the DA5 linker caused a bend that aligned its chromophores with CpG sites, enabling continuous stacking and specific water-mediated interactions at the inter-duplex contacts. Furthermore, we have shown that the different topological changes induced by DA4 and DA5 lead to the inhibition of topoisomerase 2 activities, which may account for their antitumor effects. Thus, this study lays the foundations for bis-intercalators targeting biologically relevant DNA-DNA contact structures for anticancer drug development.
Assuntos
Antineoplásicos , DNA , Substâncias Intercalantes , Conformação de Ácido Nucleico , Substâncias Intercalantes/química , Substâncias Intercalantes/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/química , Humanos , DNA/química , DNA/metabolismo , DNA Topoisomerases Tipo II/metabolismo , DNA Topoisomerases Tipo II/química , Linhagem Celular Tumoral , Inibidores da Topoisomerase II/química , Inibidores da Topoisomerase II/farmacologiaRESUMO
The difficulty in detecting viable but non-culturable (VBNC) Salmonella by culture-dependent methods poses a risk to food safety. In our study, we applied a viability test to Salmonella following a lethal treatment and to flour samples inoculated with Salmonella to evaluate the effectiveness of viability polymerase chain reaction (PCR). Our findings revealed that the combination of both ddPCR and qPCR with those DNA-intercalating dyes could quantify viable cells at low concentrations when the plate counting method failed to detect them post-inactivation. Prolonged UV exposure did not induce cell membrane disruption, as confirmed with PMA-ddPCR, with insignificant differences in gene copies. However, samples exposed to DyeTox13 and DyeTox13 + EMA showed lower gene copy numbers, implying that enzymatic activity was decreased by UV exposure duration. In addition, temperature-dependent survival in flour revealed uniform decay rates and D values (time required for a 1 log reduction) of DNA in untreated samples across various temperatures. By contrast, different decay rates were observed with DNA-intercalating dyes (DyeTox13 and DyeTox13 + EMA), showing faster metabolic activity loss at higher temperatures in flour. The decay rates and D values, determined through plate counting and those DNA-intercalating dyes, indicated the potential presence of VBNC Salmonella. A strong correlation between DyeTox13 dyes and the plate counting method suggested DyeTox13 as a rapid alternative for detecting Salmonella in flour. The ddPCR with DNA-intercalating dyes could effectively evaluate Salmonella viability, facilitating more precise monitoring of VBNC in food. IMPORTANCE: Salmonella, a major foodborne pathogen, poses significant risks, particularly to vulnerable groups like infants, older people, and the immunocompromised. Accurate detection is vital for public health and food safety, given its potential to cause severe and life-threatening symptoms. Our study demonstrated digital polymerase chain reaction (ddPCR) with DNA-intercalating dyes for identifying the different physiological statuses of Salmonella. Also, the application of ddPCR with DNA-intercalating dyes offers quantification of viable cells post-disinfection as an alternative method in food. Utilizing ddPCR and DNA-intercalating dyes, we enhanced the detection of VBNC Salmonella, a form often undetectable by conventional methods. This innovative approach could significantly improve the precision and efficiency of detection for viable Salmonella. By providing deeper insights into its transmission potential, our method is a critical tool in preventing outbreaks and ensuring the safety of food products. This research contributes substantially to global efforts in controlling foodborne illnesses and safeguarding public health.
Assuntos
DNA Bacteriano , Farinha , Microbiologia de Alimentos , Viabilidade Microbiana , Salmonella typhimurium , Farinha/microbiologia , Salmonella typhimurium/genética , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/efeitos da radiação , Salmonella typhimurium/isolamento & purificação , DNA Bacteriano/genética , Microbiologia de Alimentos/métodos , Reação em Cadeia da Polimerase/métodos , Substâncias Intercalantes/químicaRESUMO
Chemo-mechanical deformation of structured DNA assemblies driven by DNA-binding ligands has offered promising avenues for biological and therapeutic applications. However, it remains elusive how to effectively model and predict their effects on the deformation and mechanical properties of DNA structures. Here, we present a computational framework for simulating chemo-mechanical change of structured DNA assemblies. We particularly quantify the effects of ethidium bromide (EtBr) intercalation on the geometry and mechanical properties of DNA base-pairs through molecular dynamics simulations and integrated them into finite-element-based structural analysis to predict the shape and properties of DNA objects. The proposed model captures various structural changes induced by EtBr-binding such as shape variation, flexibility modulation, and supercoiling instability. It enables a rational design of structured DNA assemblies with tunable shapes and mechanical properties by binding molecules.
Assuntos
DNA , Etídio , Simulação de Dinâmica Molecular , Conformação de Ácido Nucleico , DNA/química , DNA/metabolismo , Etídio/química , Etídio/metabolismo , Substâncias Intercalantes/química , Ligantes , Pareamento de BasesRESUMO
DNA nanotubes with controllable geometries hold a wide range of interdisciplinary applications. When preparing DNA nanotubes of varying widths or distinct chirality, existing methods require repeatedly designing and synthesizing specific DNA sequences, which can be costly and laborious. Here, we proposed an intercalator-assisted DNA tile assembly method which enables the production of DNA nanotubes of diverse widths and chirality using identical DNA strands. Through adjusting the concentration of intercalators during assembly, the twisting direction and extent of DNA tiles could be modulated, leading to the formation of DNA nanotubes featuring controllable widths and chirality. Moreover, through introducing additional intercalators and secondary annealing, right-handed nanotubes could be reconfigured into distinct left-handed nanotubes. We expect that this method could be universally applied to modulating the self-assembly pathways of various DNA tiles and other chiral materials, advancing the landscape of DNA tile assembly.
Assuntos
DNA , Nanotubos , Nanotubos/química , Nanotubos/ultraestrutura , DNA/química , Conformação de Ácido Nucleico , Nanotecnologia/métodos , Substâncias Intercalantes/química , EstereoisomerismoRESUMO
We investigated in this work ruthenium-ligand bonding across the RuN framework in 12 Ru(II) polypyridyl complexes in the gas phase and solution for both singlet and triplet states, in addition to their affinity for DNA binding through π-π stacking interactions with DNA nucleobases. As a tool to assess the intrinsic strength of the ruthenium-ligand bonds, we determined local vibrational force constants via our local vibrational mode analysis software. We introduced a novel local force constant that directly accounts for the intrinsic strength of the π-π stacking interaction between DNA and the intercalated Ru(II) complex. According to our findings, [Ru(phen)2(dppz)]2+ and [Ru(phen)2(11-CN-dppz)]2+ provide an intriguing trade-off between photoinduced complex excitation and the strength of the subsequent π-π stacking interaction with DNA. [Ru(phen)2(dppz)]2+ displays a small singlet-triplet splitting and a strong π-π stacking interaction in its singlet state, suggesting a favorable photoexcitation but potentially weaker interaction with DNA in the excited state. Conversely, [Ru(phen)2(11-CN-dppz)]2+ exhibits a larger singlet-triplet splitting and a stronger π-π stacking interaction with DNA in its triplet state, indicating a less favorable photoinduced transition but a stronger interaction with DNA postexcitation. We hope our study will inspire future experimental and computational work aimed at the design of novel Ru-polypyridyl drug candidates and that our new quantitative measure of π-π stacking interactions in DNA will find a general application in the field.
Assuntos
Complexos de Coordenação , DNA , Substâncias Intercalantes , Piridinas , Rutênio , Vibração , DNA/química , Rutênio/química , Ligantes , Substâncias Intercalantes/química , Complexos de Coordenação/química , Piridinas/química , Estrutura MolecularRESUMO
A series of tetrahydrobenzo[b]thiophene derivatives was designed and synthesized as dual topoisomerase (Topo) I/II inhibitors implicating potential DNA intercalation. Ethyl-2-amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene-4-carboxylate (1) was prepared by modification of the Gewald reaction procedure using a Fe2O3 nanocatalyst and then it was used as a building block for the synthesis of tetrahydrobenzo[b]thiophene candidates (2-14). Interestingly, compound 14 showed the best cytotoxic potential against hepatocellular, colorectal, and breast cancer cell lines (IC50 = 7.79, 8.10, and 3.53 µM), respectively, surpassing doxorubicin at breast cancer (IC50 = 4.17 µM). Meanwhile, the Topo I and II inhibition assay displayed that compound 3 could exhibit the best inhibitory potential among the investigated candidates (IC50 = 25.26 and 10.01 nM), respectively, in comparison to camptothecin (IC50 = 28.34 nM) and doxorubicin (IC50 = 11.01 nM), as reference standards. In addition, the DNA intercalation assay showed that compound 14 could display the best binding affinity with an IC50 value of 77.82 µM in comparison to doxorubicin (IC50 = 58.03 µM). Furthermore, cell cycle and apoptosis analyses described that compound 3 prompts the G1 phase arrest in michigan cancer foundation-7 cancer cells and increases the apoptosis ratio by 29.31% with respect to untreated cells (2.25%). Additionally, the conducted molecular docking assured the promising binding of the investigated members toward Topo I and II with potential DNA intercalation. Accordingly, the synthesized compounds could be treated as promising anticancer candidates for future optimization.
Assuntos
Antineoplásicos , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Substâncias Intercalantes , Tiofenos , Inibidores da Topoisomerase I , Inibidores da Topoisomerase II , Humanos , Tiofenos/farmacologia , Tiofenos/síntese química , Tiofenos/química , Inibidores da Topoisomerase I/farmacologia , Inibidores da Topoisomerase I/síntese química , Inibidores da Topoisomerase I/química , Inibidores da Topoisomerase II/farmacologia , Inibidores da Topoisomerase II/síntese química , Inibidores da Topoisomerase II/química , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Relação Estrutura-Atividade , Substâncias Intercalantes/farmacologia , Substâncias Intercalantes/síntese química , Substâncias Intercalantes/química , Estrutura Molecular , Simulação de Acoplamento Molecular , Relação Dose-Resposta a Droga , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , DNA Topoisomerases Tipo II/metabolismo , Apoptose/efeitos dos fármacos , DNA , DNA Topoisomerases Tipo I/metabolismo , FarmacóforoRESUMO
Fluorescence indicators capable of binding to human immunodeficiency virus-1 (HIV-1) trans-activation responsive (TAR) RNA are powerful tools for the exploratory studies of the identification of anti-HIV drug candidates. This work presents a new design strategy for fluorogenic indicators with a transactivator of transcription (Tat)-derived peptide based on the forced intercalation of thiazole orange (TO) dyes (FIT). The developed 9-mer FIT peptide (RKKRR-TO-RRR: named FiLuP) features the TO unit integrated onto a Dap (2,3-diaminopropionic acid) residue in the middle of the Tat peptide sequence; the Q (glutamic acid) residue in the Tat peptide (RKKRR-Q-RRR) is replaced with TO as if it were an amino acid surrogate. This facilitates a significant light-up response (450-fold at λem = 541 nm, Φfree = 0.0057, and Φbound = 0.61) upon binding to TAR RNA. The response of FiLuP is highly selective to TAR RNA over other non-cognate RNAs, and FiLuP maintains strong binding affinity (Kd = 1.0 ± 0.6 nM). Significantly, in contrast to previously developed Tat peptide-based FRET probes, FiLuP is able to discriminate between "competitive" and "noncompetitive" inhibitors when used in the fluorescence indicator displacement (FID) assay. The FID assay under stringent screening conditions is also possible, enabling super-strong competitive binders toward TAR RNA to be sieved out.
Assuntos
Corantes Fluorescentes , Repetição Terminal Longa de HIV , HIV-1 , RNA Viral , Produtos do Gene tat do Vírus da Imunodeficiência Humana , Corantes Fluorescentes/química , Produtos do Gene tat do Vírus da Imunodeficiência Humana/química , Produtos do Gene tat do Vírus da Imunodeficiência Humana/metabolismo , Ligantes , Benzotiazóis/química , Quinolinas/química , Humanos , Peptídeos/química , Substâncias Intercalantes/químicaRESUMO
As a typical RNA virus, the genetic information on HIV-1 is entirely stored in RNA. The reverse transcription activity of HIV-1 reverse transcriptase (RT) plays a crucial role in the replication and transmission of the virus. Non-nucleoside RT inhibitors (NNRTIs) block the function of RT by binding to the RNA binding site on RT, with very few targeting viral RNA. In this study, by transforming planar conjugated ligands into a spiro structure, we convert classical Ru(II) DNA intercalators into a nonintercalator. This enables selective binding to HIV-1 transactivation response (TAR) RNA on the outer side of nucleic acids through dual interactions involving hydrogen bonds and electrostatic attraction, effectively inhibiting HIV-1 RT and serving as a selective fluorescence probe for TAR RNA.
Assuntos
Transcriptase Reversa do HIV , HIV-1 , Inibidores da Transcriptase Reversa , Rutênio , Transcriptase Reversa do HIV/antagonistas & inibidores , Transcriptase Reversa do HIV/metabolismo , Inibidores da Transcriptase Reversa/química , Inibidores da Transcriptase Reversa/farmacologia , Inibidores da Transcriptase Reversa/metabolismo , Ligantes , HIV-1/enzimologia , HIV-1/efeitos dos fármacos , Rutênio/química , Rutênio/farmacologia , RNA Viral/metabolismo , RNA Viral/química , Compostos de Espiro/química , Compostos de Espiro/farmacologia , Compostos de Espiro/metabolismo , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/síntese química , Substâncias Intercalantes/química , Substâncias Intercalantes/farmacologia , Estrutura Molecular , Humanos , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Repetição Terminal Longa de HIV , Sítios de LigaçãoRESUMO
Chemotherapeutic anthracyclines, like doxorubicin (DOX), are drugs endowed with cytostatic activity and are widely used in antitumor therapy. Their molecular mechanism of action involves the formation of a stable anthracycline-DNA complex, which prevents cell division and results in cell death. It is known that elevated DOX concentrations induce DNA chain loops and overlaps. Here, for the first time, tip-enhanced Raman scattering was used to identify and localize intercalated DOX in isolated double-stranded calf thymus DNA, and the correlated near-field spectroscopic and morphologic experiments locate the DOX molecules in the DNA and provide further information regarding specific DOX-nucleobase interactions. Thus, the study provides a tool specifically for identifying intercalation markers and generally analyzing drug-DNA interactions. The structure of such complexes down to the molecular level provides mechanistic information about cytotoxicity and the development of potential anticancer drugs.
Assuntos
DNA , Doxorrubicina , Análise Espectral Raman , Doxorrubicina/farmacologia , Doxorrubicina/química , DNA/química , Animais , Bovinos , Substâncias Intercalantes/química , Substâncias Intercalantes/farmacologia , Antibióticos Antineoplásicos/farmacologia , Antibióticos Antineoplásicos/químicaRESUMO
In recent years, extensive research has been directed towards understanding the interactions between various zinc complexes with DNA, specifically delving into their intercalation and binding behaviors. The binding of zinc complexes to DNA is particularly intriguing due to their distinctive intercalating capabilities. This study unveils a remarkable phenomenon observed with a specific Zn complex, ([B-Zn-N3], where B is a Schiff base ligand), during DNA intercalation investigations in the popular DMSO-Water binary solvent mixture. An unanticipated observation revealed time-dependent changes in the UV-visible absorption spectroscopic studies, coupled with the existence of an isosbestic point. This observation questions the stability of the intercalating agent itself during the intercalation process. The emergence of a decomposed product during the intercalation study has been confirmed through various analytical techniques, including CHN analysis, MALDI mass, XPS, Raman spectroscopy, and Powder XRD. The change in the chemical species on intercalation is further substantiated by theoretical studies, adding depth to our understanding of the intricate dynamics at play during DNA intercalation with the [B-Zn-N3] complex in the DMSO-Water system.
Assuntos
DNA , Dimetil Sulfóxido , Substâncias Intercalantes , Água , Dimetil Sulfóxido/química , Substâncias Intercalantes/química , DNA/química , DNA/metabolismo , Água/química , Análise Espectral Raman , Zinco/química , Espectrofotometria Ultravioleta , Complexos de Coordenação/química , Complexos de Coordenação/metabolismo , Bases de Schiff/químicaRESUMO
Proflavine (PF), an acridine DNA intercalating agent, has been widespread applied as an anti-microbial and topical antiseptic agent due to its ability to suppress DNA replication. On the other hand, various studies show that PF intercalation to DNA can increase photogenotoxicity and has potential chances to induce carcinomas of skin appendages. However, the effects of PF intercalation on the photophysical and photochemical properties of DNA have not been sufficiently explored. In this study, the excited state dynamics of the PF intercalated d(GC)9 ⢠d(GC)9 and d(AT)9 ⢠d(AT)9 DNA duplex are investigated in an aqueous buffer solution. Under 267 nm excitation, we observed ultrafast charge transfer (CT) between PF and d(GC)9 ⢠d(GC)9 duplex, generating a CT state with an order of magnitude longer lifetime compared to that of the intrinsic excited state reported for the d(GC)9 ⢠d(GC)9 duplex. In contrast, no excited state interaction was detected between PF and d(AT)9 ⢠d(AT)9. Nevertheless, a localized triplet state with a lifetime over 5 µs was identified in the PF-d(AT)9 ⢠d(AT)9 duplex.
Assuntos
Substâncias Intercalantes , Proflavina , Proflavina/química , Análise Espectral , Substâncias Intercalantes/química , DNA/químicaRESUMO
Cytosine rich sequences can form intercalated, i-motif DNA structures stabilized by hemi-protonated cytosine:cytosine base pairing. These sequences are often located in regulatory regions of genes such as promoters. Ligands targeting i-motif structures may provide potential leads for treatments for genetic disease. The focus on ligands interacting with i-motif DNA has been increasing in recent years. Here, we describe the fluorescent intercalator displacement (FID) assay using thiazole orange binding i-motif DNA and assess the binding affinity of a ligand to the i-motif DNA by displacing thiazole orange. This provides a time and cost-effective high throughput screening of ligands against secondary DNA structures for hit identification.
Assuntos
DNA , Substâncias Intercalantes , Substâncias Intercalantes/química , Ligantes , DNA/metabolismo , Pareamento de Bases , Citosina/químicaRESUMO
In this article, a new series of 2-((3,5-disubstituted-2-thioxo-imidazol-1-yl)imino)acenaphthylen-1(2H)-ones were synthesized. Imidazole-2-thione with acenaphthylen-one gave a hybrid scaffold that integrated key structural elements essential for DNA damage via direct DNA intercalation and inhibition of the topoisomerase II enzyme. All the synthesized compounds were screened to detect their DNA damage using a terbium fluorescent probe. Results demonstrated that 4-phenyl-imidazoles 5b and 5e in addition to 4-(4-chlorophenyl)imidazoles 5h and 5j would induce detectable potent damage in ctDNA. The four most potent compounds as DNA intercalators were further evaluated for their antiproliferative activity against HepG2, MCF-7 and HCT-116 utilizing the MTT assay. The highest anticancer activity was recorded with compounds 5b and 5h against the breast cancer cell line MCF-7 which were 1.5- and 3- folds more active than doxorubicin, respectively. Therefore, imidazole-2-thione tethered acenaphthylenone derivatives can be considered as promising scaffold for the development of effective dual DNA intercalators and topoisomerase II inhibitors.
Assuntos
Antineoplásicos , Inibidores da Topoisomerase II , Inibidores da Topoisomerase II/farmacologia , Inibidores da Topoisomerase II/química , Relação Estrutura-Atividade , Substâncias Intercalantes/farmacologia , Tionas/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Imidazóis/farmacologia , DNA , Apoptose , Simulação de Acoplamento Molecular , DNA Topoisomerases Tipo II/metabolismo , Proliferação de CélulasRESUMO
In cancer therapy, DNA intercalators are mainly known for their capacity to kill cells by inducing DNA damage. Recently, several DNA intercalators have attracted much interest given their ability to inhibit RNA Polymerase I transcription (BMH-21), evict histones (Aclarubicin) or induce chromatin trapping of FACT (Curaxin CBL0137). Interestingly, these DNA intercalators lack the capacity to induce DNA damage while still retaining cytotoxic effects and stabilize p53. Herein, we report that these DNA intercalators impact chromatin biology by interfering with the chromatin stability of RNA polymerases I, II and III. These three compounds have the capacity to induce degradation of RNA polymerase II and they simultaneously enable the trapping of Topoisomerases TOP2A and TOP2B on the chromatin. In addition, BMH-21 also acts as a catalytic inhibitor of Topoisomerase II, resembling Aclarubicin. Moreover, BMH-21 induces chromatin trapping of the histone chaperone FACT and propels accumulation of Z-DNA and histone eviction, similarly to Aclarubicin and CBL0137. These DNA intercalators have a cumulative impact on general transcription machinery by inducing accumulation of topological defects and impacting nuclear chromatin. Therefore, their cytotoxic capabilities may be the result of compounding deleterious effects on chromatin homeostasis.
Assuntos
Cromatina , DNA Topoisomerases Tipo II , Substâncias Intercalantes , RNA Polimerase II , Humanos , Antígenos de Neoplasias/metabolismo , Antígenos de Neoplasias/genética , Carbazóis , Cromatina/metabolismo , Dicetopiperazinas , DNA/metabolismo , DNA/química , Dano ao DNA , DNA Topoisomerases Tipo II/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Grupo de Alta Mobilidade/metabolismo , Proteínas de Grupo de Alta Mobilidade/genética , Histonas/metabolismo , Substâncias Intercalantes/farmacologia , Substâncias Intercalantes/química , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/genética , RNA Polimerase I/metabolismo , RNA Polimerase I/antagonistas & inibidores , RNA Polimerase II/metabolismo , RNA Polimerase III/metabolismo , Inibidores da Topoisomerase II/farmacologia , Transcrição Gênica/efeitos dos fármacos , Fatores de Elongação da Transcrição/metabolismo , Fatores de Elongação da Transcrição/genética , Aclarubicina/farmacologiaRESUMO
Pyrolysis is effective in reducing the volume of solid waste and sludge, and produces less pollutants than incineration and landfill, but the process still suffers from heavy metal pollution. Four types of intercalated-exfoliated modified vermiculite (UIV, DIV, TIV and 3IV) were prepared using urea, dimethylsulfoxide, tributyl phosphate and 3-aminopropyltriethoxysilane as intercalators for the control of Cd, Cr, Cu, Pb and Zn in municipal sewage sludge (MSL), paper mill sludge (PML), municipal domestic waste (MWA) and aged refuse (AFE). The larger the interlayer spacing of the vermiculite, the more favorable the retention of heavy metals. 3IV was the most effective additive, with an average retention of more than 75 % of all heavy metals at 450 â for the four raw materials. Cr, Cu, Pb and Zn were all at low potential ecological risk (Pr), while Cd was moderate or considerable Pr, and the addition of 3IV reduced the Pr. Distribution of intercalators between vermiculite interlayers was haphazard, and interlayer spacing results were close to those of the experiment (except for tributyl phosphate). The reactive electrons mainly flowed from the Highest Occupied Molecular Orbital (HOMO) of vermiculite flakes to the Lower Unoccupied Molecular Orbital (LUMO) of heavy metal chlorides. In contrast, the reactive electrons mostly flowed from the HOMO of heavy metal oxides to the LUMO of vermiculite flakes. Heavy metal oxides were more readily adsorbed on vermiculite flakes than heavy metal chlorides, and the adsorption capacity of Cr and Zn was stronger than that of Cd, Pb and Cu.
Assuntos
Metais Pesados , Organofosfatos , Esgotos , Resíduos Sólidos , Pirólise , Cádmio , Substâncias Intercalantes , Chumbo , Metais Pesados/análise , Silicatos de AlumínioRESUMO
Bisphenol A (BPA), an important endocrine disrupting compound, has infiltrated human daily lives through electronic devices, food containers, and children's toys. Developing of novel BPA assay methods with high sensitivity holds tremendous importance in valuing the pollution state. Here, we constructed an ultrasensitive photoelectrochemical (PEC) aptasensor for BPA determination by regulating photoactivities of CdS/Ni-based metal-organic framework (CdS/Ni-MOF) with [Ru(bpy)2dppz]2+ sensitizer. CdS/Ni-MOF spheres exhibited excellent photocatalytic performance, serving as a potential sensing platform for the construction of target recognition process. [Ru(bpy)2dppz]2+ were embedded into DNA double-stranded structure, functioning as sensitizer for modulating the signal response of the developed PEC aptasensor. The proposed PEC sensor exhibited outstanding analytical performances, including a wide linear range (0.1 to 1000.0 nM), low detection limit (0.026 nM, at 3σ/m), excellent selectivity, and high stability. This work provides a perspective for the design of ideal photosensitive materials and signal amplification strategies and extends their application in environment analysis.
Assuntos
Técnicas Biossensoriais , Estruturas Metalorgânicas , Fenóis , Criança , Humanos , Substâncias Intercalantes , Técnicas Biossensoriais/métodos , Compostos Benzidrílicos , DNARESUMO
Cancer is a global public health problem characterized by deviations in the mechanisms that control cell proliferation, resulting in mutations and variations in the structure of DNA. The mechanisms of action of chemotherapeutic drugs are related to their interactions and binding with DNA; consequently, the development of antineoplastic agents that target DNA has extensively focused on use of acridine, a heterocyclic molecule that binds to deoxyribonucleic acid via intercalation, a process that modifies DNA and makes replication impossible. In this context, this study aimed to computationally investigate how acridine intercalators interact with DNA by evaluating the mechanism of interactions, binding, and interaction energies using quantum mechanics calculations. Molecular electrostatic potential (MEP) analysis revealed that acridine has well- distributed negative charges in the center of the molecule, indicative of a dominant electron-rich region. Acridine exhibits well-defined π orbitals (HOMO and LUMO) on the aromatic rings, suggesting that charge transfer occurs within the molecule and may be responsible for the pharmacological activity of the compound. Structural analysis revealed that acridine interacts with DNA mainly through hydrogen bonds between HAcridine ODNA with bond lengths ranging from 2.370â¯Å to 3.472â¯Å. The Binding energy (ΔEBind) showed that acridine interacts with DNA effectively for all complexes and the electronic energy results (E+ZPE) for complexes revealed that the complexes are more stable when the DNA-centered acridine molecule. The Laplacian-analysis topological QTAIM parameter (∇2ρ(r)) and total energy (H(r)) categorized the interactions as being non-covalent in nature. The RGD peak distribution in the NCI analysis reveals the presence of van der Waals interactions, predominantly between the intercalator and DNA. Accordingly, we confirm that acridine/DNA interactions are relevant for understanding how the intercalator acts within nucleic acids.