Differentiation and distributions of DNA/cisplatin crosslinks by liquid chromatography-electrospray ionization-infrared multiphoton dissociation mass spectrometry

The multifaceted roles of mass spectrometric analysis in nucleic acids drug discovery and development

The deceptively simple concepts of mass determination and fragment analysis are the basis for the application of mass spectrometry (MS) to a boundless range of analytes, including fundamental components and polymeric forms of nucleic acids (NAs). This platform affords the intrinsic ability to observe first-hand the effects of NA-active drugs on the chemical structure, composition, and conformation of their targets, which might affect their ability to interact with cognate NAs, proteins, and other biomolecules present in a natural environment. The possibility of interfacing with high-performance separation techniques represents a multiplying factor that extends these capabilities to cover complex sample mixtures obtained from organisms that were exposed to NA-active drugs. This report provides a brief overview of these capabilities in the context of the analysis of the products of NA-drug activity and NA therapeutics. The selected examples offer proof-of-principle of the applicability of this platform to all phases of the journey undertaken by any successful NA drug from laboratory to bedside, and provide the rationale for its rapid expansion outside traditional laboratory settings in support to ever growing manufacturing operations.

Prophylactic consequences of sodium salicylate nanoparticles in cisplatin-mediated hepatotoxicity

Unintended side effects linked to the antineoplastic drug cisplatin are a major drawback in its clinical application. The underlying source of these side effects include the generation of reactive oxygen species which are toxic and damaging to tissues and organs. In the present study the anti-inflammatory and antioxidant potential of sodium salicylate was assessed against cisplatin-induced hepatotoxicity in albino rats. Sodium salicylate was used as a model drug and loading into hollow structured porous silica using ultrasound-assisted sol-gel method to produce a nanoemulsion. Transmission Electron Microscopy and Dynamic Light scattering analysis were employed to assess the structural properties and stability of this model. Liver function was assessed by measuring biomarkers including ALT, AST & GGT and oxidant/antioxidant markers including MDA, NO, PON, GSH, MCP1 & AVP in serum or liver tissue. Additionally, blood leukocyte DNA damage was evaluated. Cisplatin significantly altered the normal levels of all biomarkers confirming its hepatotoxic effects. In contrast, treatment with sodium salicylate-loaded silica nanoemulsion significantly restored the levels of these markers. The finding suggests the protective effects of this model drug in preventing cisplatin-induced hepatotoxicity, and therefore may have implications in attenuating cisplatin-induced hepatotoxicity.

Recent developments in the characterization of nucleic acids by liquid chromatography, capillary electrophoresis, ion mobility, and mass spectrometry (2010-2020)

The development of new strategies for the analysis of nucleic acids has gained momentum due to the increased interest in using these biomolecules as drugs or drug targets. The application of new mass spectrometry ion activation techniques and the optimization of separation methods including liquid chromatography, capillary electrophoresis, and ion mobility have allowed more detailed characterization of nucleic acids and oligonucleotide therapeutics including confirmation of sequence, localization of modifications and interaction sites, and structural analysis as well as identification of failed sequences and degradation products. This review will cover tandem mass spectrometry methods as well as the recent developments in liquid chromatography, capillary electrophoresis, and ion mobility coupled to mass spectrometry for the analysis of nucleic acids and oligonucleotides.

A novel effect of Aprepitant: Protection for cisplatin-induced nephrotoxicity and hepatotoxicity

Cisplatin is widely used chemotherapeutic drug and have some serious side effects as tissue toxicity and nausea and vomiting. Aprepitant is used in clinic as an anti-emetic drug for cisplatin treated patient to prevent nausea and vomiting. We aimed to investigate the protective effects of Aprepitant on cisplatin-induced nephrotoxicity and hepatotoxicity. In total 42 male rats were separated into six groups (n = 7). A single dose of cisplatin (10 mg/kg i.p.) was administered to induce toxicity on first day. Different doses of Aprepitant (5, 10 and 20 mg/kg, p.o.) were given to treatment groups during 3 days. After the experimental procedures serum enzymes (ALT, AST, ALP, BUN and Creatinin), kidney and liver oxidative parameters (SOD, GSH and MDA), inflammatory cytokines (TNF-α and NF-κB) and Cyp2e1 expressions analyzed. Histopathological investigations also performed for all groups. Cisplatin caused tissue toxicity in both kidney and liver. Serum enzymes, tissue cytokines and oxidative stress were increased after the Cis treatment. Aprepitant treatment normalized all parameters compared to cisplatin treated group. Cisplatin significantly increased the Cyp2e1 expression in the kidney while significantly decreased in the liver compared to Healthy group. Histopathologically, it was shown that cisplatin causes a lot of abnormal structures as inflammatory infiltration and necrosis on the liver and kidney. Similar the biochemical and molecular results, aprepitant showed positive effects on tissue pathological parameters. With its main anti-emetic effect, Aprepitant treatment may be an effective option for cancer patients if they have additional injury as nephrotoxicity and hepatotoxicity due to cisplatin.

Ellagic acid ameliorates cisplatin induced hepatotoxicity in colon carcinogenesis

The clinical application of cisplatin (CP), one of the most extensively used antineoplastic drug, is restricted by its numerous side effects. CP's antitumor potential resides in the free generation of reactive oxygen species leading to oxidative stress. This stress is a source of the side effects associated with its use. Ellagic acid (EA), a polyphenol is known to possess multiple health benefits owing to its antioxidant properties. EA is largely metabolized by the colon microbiota of different mammals and therefore was a polyphenol of choice in the present study. The present study was thus carried out to explore the protective potential of EA on CP induced hepatotoxicity in colon tumor bearing mice. The administration of EA (10 mg/kg bwt po daily for 6 weeks) significantly ameliorated the toxicity caused by CP (5 mg/kg bwt ip once a week for 4 weeks). Activities of liver marker enzymes and lactate dehydrogenase were brought back to normal. EA cotreatment also led to a marked reduction in the extent of peroxidative damage to liver tissue as was evident from the improvement in the histopathological changes observed and FT-IR analysis. The present study, therefore, suggests that the administration of EA reduces the CP-induced hepatotoxicity, thereby emerging out as a potential candidate for chemopreventive action.

Binding motifs of cisplatin interaction with simple biomolecules and aminoacid targets probed by IR ion spectroscopy

The primary intermediates resulting from the interaction of cisplatin, cis-(PtCl2(NH3)2], most widespread antitumor drug, with biomolecular targets are characterized. Electrospray ionization is used to deliver ions formed in solution into the gas phase where they are structurally interrogated by vibrational “action” spectroscopy in conjunction with quantum chemical calculations. The aquation products, cis-[PtX(NH3)2(H2O)]+ (X = Cl, OH), lying along the path responsible for biological activity, are shown to display distinctive features responding to ligation pattern and optimized geometry. The IR spectra of trans-[PtX(NH3)2(H2O)]+ are different, testifying that cis and trans complexes are stable, non interconverting species both in solution and in the gas phase. Ligand substitution by simple nucleophiles (L = pyridine, 4(5)-methylimidazole, thioanisole, trimethylphosphate, acetamide, dimethylacetamide, urea and thiourea) yields cis-[PtCl(NH3)2(L)]+ complexes displaying remarkable regioselectivity whenever L presents multiple candidate platination sites. The incipient formation of cisplatin-derived complexes with the recognized biological amino acid targets L-histidine (His) and L-methionine (Met) has been investigated revealing the primary platination event to be mainly directed at the Nπ atom of the imidazole side chain of His and to the thiomethyl sulfur of Met. The isomer and conformer population of the ensuing cis-[PtCl(NH3)2(Met/His)]+ complexes, sampled in the gas phase, can be ascertained by photofragmentation kinetics on isomer/conformer specific resonances.

The Application of ATR-FTIR Spectroscopy and the Reversible DNA Conformation as a Sensor to Test the Effectiveness of Platinum(II) Anticancer Drugs

Platinum(II) complexes have been found to be effective against cancer cells. Cisplatin curbs cell replication by interacting with the deoxyribonucleic acid (DNA), reducing cell proliferation and eventually leading to cell death. In order to investigate the ability of platinum complexes to affect cancer cells, two examples from the class of polyfluorophenylorganoamidoplatinum(II) complexes were synthesised and tested on isolated DNA. The two compounds trans-[N,N′-bis(2,3,5,6-tetrafluorophenyl)ethane-1,2-diaminato(1-)](2,3,4,5,6-pentafluorobenzoato)(pyridine)platinum(II) (PFB) and trans-[N,N′-bis(2,3,5,6-tetrafluorophenyl)ethane-1,2-diaminato(1-)](2,4,6-trimethylbenzoato)(pyridine)platinum(II) (TMB) were compared with cisplatin through their reaction with DNA. Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy was applied to analyse the interaction of the Pt^(II) complexes with DNA in the hydrated, dehydrated and rehydrated states. These were compared with control DNA in acetone/water (PFB, TMB) and isotonic saline (cisplatin) under the same conditions. Principle Component Analysis (PCA) was applied to compare the ATR-FTIR spectra of the untreated control DNA with spectra of PFB and TMB treated DNA samples. Disruptions in the conformation of DNA treated with the Pt^(II) complexes upon rehydration were mainly observed by monitoring the position of the IR-band around 1711 cm⁻¹ assigned to the DNA base-stacking vibration. Furthermore, other intensity changes in the phosphodiester bands of DNA at ~1234 cm⁻¹ and 1225 cm⁻¹ and shifts in the dianionic phosphodiester vibration at 966 cm⁻¹ were observed. The isolated double stranded DNA (dsDNA) or single stranded DNA (ssDNA) showed different structural changes when incubated with the studied compounds. PCA confirmed PFB had the most dramatic effect by denaturing both dsDNA and ssDNA. Both compounds, along with cisplatin, induced changes in DNA bands at 1711, 1088, 1051 and 966 cm⁻¹ indicative of DNA conformation changes. The ability to monitor conformational change with infrared spectroscopy paves the way for a sensor to screen for new anticancer therapeutic agents.

Photodissociation mass spectrometry: new tools for characterization of biological molecules

Photodissociation mass spectrometry combines the ability to activate and fragment ions using photons with the sensitive detection of the resulting product ions by mass spectrometry. This combination affords a versatile tool for characterization of biological molecules. The scope and breadth of photodissociation mass spectrometry have increased substantially over the past decade as new research groups have entered the field and developed a number of innovative applications that illustrate the ability of photodissociation to produce rich fragmentation patterns, to cleave bonds selectively, and to target specific molecules based on incorporation of chromophores. This review focuses on many of the key developments in photodissociation mass spectrometry over the past decade with a particular emphasis on its applications to biological molecules.