Development of the electrochemical, spectroscopic and molecular docking approaches toward the investigation of interaction between DNA and anti-leukemic drug azacytidine

Voltammetric quantification, spectroscopic, and DFT studies on the binding of the antineoplastic drug Azacitidine with DNA

In this study, experimental studies were carried out to explore the action mechanism of the anti-cancer drug Azacitidine on the double-stranded DNA (dsDNA). The drug binding constant (Kb) was found to be 4.13 ± 0.23 × 105 M-1 using voltammetric measurements and 1.67 ± 0.24 × 105 M-1 using the fluorescence spectroscopy. Both values are close to the values of 2.04 ± 0.30 × 105 M-1 for deoxyguanosine (dGuO) and 1.23 ± 0.30 × 105 M-1 for deoxyadenosine (dAdo). In the displacement studies, the ethidium bromide, strong DNA intercalator, was replaced by the Azacitidine, hence caused a decrease on the fluorescence emission intensity. In thermal denaturation studies, the increase of 8.60 °C in the melting temperature upon introduction of the Azacitidine into the dsDNA solution cleary indicated intercalation binding mode of the drug. The experimental and theoretical IR spectra of Azacitidine, dsDNA and their H-bonded complex were confirmed the Azacitidine's intercalation ability to induce cytotoxicity. We also developed a method for the detection of Azacitidine at low concentrations using the differential pulse voltammetry (DPV). The peak current decreases in the oxidation signals of the deoxyguanosine obtained voltammetrically upon the interaction of Azacitidine and dsDNA allowed a sensitive determination of Azacitidine in pH 4.80 acetate buffer. A linear dependence of the deoxyguanosine oxidation signals was observed within the range of 2-20 µM Azacitidine, with a limit of detection (LOD) 0.62 µM.

Electroanalysis in Pharmacogenomic Studies: Mechanisms of Drug Interaction with DNA

The review discusses electrochemical methods for analysis of drug interactions with DNA. The electroanalysis method is based on the registration of interaction-induced changes in the electrochemical oxidation potential of heterocyclic nitrogenous bases in the DNA molecule and in the maximum oxidation current amplitude. The mechanisms of DNA-drug interactions can be identified based on the shift in the electrooxidation potential of heterocyclic nitrogenous bases toward more negative (cathodic) or positive (anodic) values. Drug intercalation into DNA shifts the electrochemical oxidation potential to positive values, indicating thermodynamically unfavorable process that hinders oxidation of nitrogenous bases in DNA. The potential shift toward the negative values indicates electrostatic interactions, e.g., drug binding in the DNA minor groove, since this process does not interfere with the electrochemical oxidation of bases. The concentration-dependent decrease in the intensity of electrochemical oxidation of DNA bases allows to quantify the type of interaction and calculate the binding constants.

Electrochemical DNA biosensors developed for the monitoring of biointeractions with drugs: a review

The interaction of drugs with DNA is important for the discovery of novel drug molecules and for understanding the therapeutic effects of drugs as well as the monitoring of side effects. For this reason, many studies have been carried out to investigate the interactions of drugs with nucleic acids. In recent years, a large number of studies have been performed to electrochemically detect drug-DNA interactions. The fast, sensitive, and accurate results of electrochemical techniques have resulted in a leading role for their implementation in this field. By means of electrochemical techniques, it is possible not only to demonstrate drug-DNA interactions but also to quantitatively analyze drugs. In this context, electrochemical biosensors for drug-DNA interactions have been examined under different headings including anticancer, antiviral, antibiotic, and central nervous system drugs as well as DNA-targeted drugs. An overview of the studies related to electrochemical DNA biosensors developed for the detection of drug-DNA interactions that were reported in the last two decades in the literature is presented herein along with their applications and they are discussed together with their future perspectives.

Interaction of Doxorubicin Embedded into Phospholipid Nanoparticles and Targeted Peptide-Modified Phospholipid Nanoparticles with DNA

The interactions of dsDNA with new targeted drug delivery derivatives of doxorubicin (DOX), such as DOX embedded into phospholipid nanoparticles (NPhs) and DOX with the NGR targeted peptide-modified NPhs were studied electrochemically by differential pulse voltammetry technique. Screen-printed electrodes (SPEs), modified with stable fine dispersions of carbon nanotubes (CNTs), were used for quantitative electrochemical investigations of direct electrochemical oxidation of guanine, adenine, and thymine heterocyclic bases of dsDNA, and their changes in the presence of DOX nanoderivatives. Analysing the shifts of peak potentials of nucleobases in the presence of drug, we have shown that the doxorubicin with NGR targeted peptide changed the mode of interaction in DNA-drug complexes from intercalative to electrostatic. Binding constants (K_b) of DNA-drug complexes were calculated in accordance with adenine, guanine, and thymine oxidation signals. Based on our experiments, we have proven that the surface modification of a drug delivery system with NGR targeted peptide dramatically changed the mechanism of interaction of drug with genetic material. DNA-mediated drug toxicity was calculated based on the concentration-dependent "response" of heterocyclic nucleobases on drug influence. DOX, DOX-loaded phospholipid nanoparticles (NPhs), and DOX with NGR addressed peptide-modified NPhs were moderately toxic in the concentration range of 0.5-290 µM.

Revealing the effects of ligands of silver nanoclusters on the interactions between them and ctDNA: Abstraction to visualization

Silver nanoclusters (AgNCs) have been widely applied in the field of biology, drug therapy and cell imaging in the last decade. In order to study the biosafety of AgNCs, GSH-AgNCs and DHLA-AgNCs were synthesized using glutathione (GSH) and dihydrolipoic acid (DHLA) as ligands, and their interactions with calf thymus DNA (ctDNA) from abstraction to visualization were studied. The results of spectroscopy, viscometry and molecular docking demonstrated that GSH-AgNCs mainly bound to ctDNA in a groove mode, while DHLA-AgNCs were both groove and intercalation binding. Fluorescence experiments suggested that the quenching mechanism of both AgNCs to the emission of ctDNA-probe were both in static mode, and thermodynamic parameters demonstrated that the main forces between GSH-AgNCs and ctDNA were hydrogen bonds and van der Waals forces, while hydrogen bonds and hydrophobic forces contributed to the binding of DHLA-AgNCs to ctDNA. The binding strength demonstrated that DHLA-AgNCs bound to ctDNA more strongly than that of GSH-AgNCs. The results of circular dichroism (CD) spectroscopy reflected small effects of both AgNCs on the structure of ctDNA. This study will support the theoretical foundation for the biosafety of AgNCs and have a guiding significance for the preparation and application of AgNCs.

Interaction between Benzo[a]anthracene 7,2-dione 7-oxime (BZA) and calf thymus dsDNA using electroanalytical genosensor

In the present study, the objective was to evaluate in situ interaction between Benzo[a]anthracene 7,2-dione 7-oxime (BZA) and calf thymus dsDNA (ct-dsDNA) using electroanalytical genosensor. Analytical techniques based on Ultraviolet/Visible (UV-Vis) spectroscopy and electroanalytical were used to investigate the interaction processes in solution and immobilized on carbon screen-printed electrodes modified with electrochemical mediator Meldola blue. In addition, was possible to evaluate the degree of damage caused to the genetic material by the analyte through of toxicity estimate (S%). The interaction evaluated by genosensor showed processes of intercalation, degradation, and breaks of the double strand of ct-dsDNA, suggesting that the interaction simulates highly toxic (values varying from 0.6 to 0.8 μA in 48 h of interaction), such as 8-oxoguanine (+0.48 V), which is a by-product of guanine oxidation. Furthermore, monitoring A (+1.10 V) after 1 h showed an S% value between 50 and 90%, indicative of high toxicity, and monitoring G (+0.85 V), which showed S>90%, indicated no toxicity after 10 min. Overall, the electroanalytical genosensor developed in a miniaturized system displayed good reproducibility and stability over time being a quick alternative for assesses the degree of toxicity between toxic xenobiotics and biologically electroactive molecules, such as DNA.

Electrochemical DNA sensors for drug determination

In this review, recent achievements in the development of the DNA biosensors developed for the drug determination have been presented with particular emphasis to the main principles of their assembling and signal measurement approaches. The design of the DNA sensors is considered with characterization of auxiliary components and their necessity for the biosensor operation. Carbon nanomaterials, metals and their complexes as well as electropolymerized polymers are briefly described in the assembly of DNA sensors. The performance of the DNA sensors is summarized within 2017-2022 for various drugs and factors influencing the sensitivity and selectivity of the response are discussed. Special attention is paid to the mechanism of the signal generation and possible drawbacks in the analysis of real samples.