Platinum-based chemotherapy: trends in organic nanodelivery systems

Despite the investment in platinum drugs research, cisplatin, carboplatin and oxaliplatin are still the only Pt-based compounds used as first line treatments for several cancers, with a few other compounds being approved for administration in some Asian countries. However, due to the severe and worldwide impact of oncological diseases, there is an urge for improved chemotherapeutic approaches. Furthermore, the pharmaceutical application of platinum complexes is hindered by their inherent toxicity and acquired resistance. Nanodelivery systems rose as a key strategy to overcome these challenges, with recognized versatility and ability towards improving the safety, bioavailability and efficacy of the available drugs. Among the known nanocarriers, organic systems have been widely applied, taking advantage of their potential as drug vehicles. Researchers have mainly focused on the development of lipidic and polymeric carriers, including supramolecular structures, with an overall improvement of encapsulated platinum complexes. Herein, an overview of recent trends and strategies is presented, with the main focus on the encapsulation of platinum compounds into organic nanocarriers, showcasing the evolution in the design and development of these promising systems. This comprehensive review highlights formulation methods as well as characterization procedures, providing insights that may be helpful for the development of novel platinum nanocarriers aiming at future pharmaceutical applications.

FoxG1/BNIP3 axis promotes mitophagy and blunts cisplatin resistance in osteosarcoma

Cisplatin (CDDP) is a commonly used chemotherapeutic for osteosarcoma (OS) patients, and drug resistance remains as a major hurdle to undermine the treatment outcome. Here, we investigated the potential involvement of FoxG1 and BNIP3 in CDDP resistance of OS cells. FoxG1 and BNIP3 expression levels were detected in the CDDP-sensitive and CDDP-resistant OS tumors and cell lines. Mitophagy was observed through transmission electron microscope analysis. The sensitivity to CDDP in OS cells upon FoxG1 overexpression was examined in cell and animal models. We found that FoxG1 and BNIP3 showed significant downregulation in the CDDP-resistant OS tumor samples and cell lines. CDDP-resistant OS tumor specimens and cells displayed impaired mitophagy. FoxG1 overexpression promoted BNIP3 expression, enhanced mitophagy in CDDP-resistant OS cells, and resensitized the resistant cells to CDDP treatment in vitro and in vivo. Our data highlighted the role of the FoxG1/BNIP3 axis in regulating mitophagy and dictating CDDP resistance in OS cells, suggesting targeting FoxG1/BNIP3-dependent mitophagy as a potential strategy to overcome CDDP resistance in OS.

MicroRNAs as the pivotal regulators of cisplatin resistance in osteosarcoma

Osteosarcoma (OS) is an aggressive bone tumor that originates from mesenchymal cells. It is considered as the eighth most frequent childhood cancer that mainly affects the tibia and femur among the teenagers and young adults. OS can be usually diagnosed by a combination of MRI and surgical biopsy. The intra-arterial cisplatin (CDDP) and Adriamycin is one of the methods of choices for the OS treatment. CDDP induces tumor cell death by disturbing the DNA replication. Although, CDDP has a critical role in improving the clinical complication in OS patients, a high ratio of CDDP resistance is observed among these patients. Prolonged CDDP administrations have also serious side effects in normal tissues and organs. Therefore, the molecular mechanisms of CDDP resistance should be clarified to define the novel therapeutic modalities in OS. Multidrug resistance (MDR) can be caused by various cellular and molecular processes such as drug efflux, detoxification, and signaling pathways. MicroRNAs (miRNAs) are the key regulators of CDDP response by the post transcriptional regulation of target genes involved in MDR. In the present review we have discussed all of the miRNAs associated with CDDP response in OS cells. It was observed that the majority of reported miRNAs increased CDDP sensitivity in OS cells through the regulation of signaling pathways, apoptosis, transporters, and autophagy. This review highlights the miRNAs as reliable non-invasive markers for the prediction of CDDP response in OS patients.

Cu2+-Chelating Mesoporous Silica Nanoparticles for Synergistic Chemotherapy/Chemodynamic Therapy

In this study, a pH-responsive controlled-release mesoporous silica nanoparticle (MSN) formulation was developed. The MSNs were functionalized with a histidine (His)-tagged targeting peptide (B3int) through an amide bond, and loaded with an anticancer drug (cisplatin (CP)) and a lysosomal destabilization mediator (chloroquine (CQ)). Cu²⁺ was then used to seal the pores of the MSNs via chelation with the His-tag. The resultant nanoparticles showed pH-responsive drug release, and could effectively target tumor cells via the targeting effect of B3int. The presence of CP and Cu²⁺ permits reactive oxygen species to be generated inside cells; thus, the chemotherapeutic effect of CP is augmented by chemodynamic therapy. In vitro and in vivo experiments showed that the nanoparticles are able to effectively kill tumor cells. An in vivo cancer model revealed that the nanoparticles increase apoptosis in tumor cells, and thereby diminish the tumor volume. No off-target toxicity was noted. It thus appears that the functionalized MSNs developed in this work have great potential for targeted, synergistic anticancer therapies.

Probing the interaction of new and biologically active Pd(II) complex with DNA/BSA via joint experimental and computational studies along with thermodynamic, NLO, FMO and NBO analysis

Treatment with transition metal complexes is an efficient method to fight with cancer. Therefore, a new transition metal complex formulated as [Pd(1, 3-pn)(acac)]Cl (pn and acac stand for propylendiamine and acetylacetonate, respectively) was synthesized and analyzed using ¹H NMR, Fourier transform infrared, electronic absorption spectroscopy techniques as well as elemental analysis and conductivity measurement. The geometry optimization, frontier molecular orbital (FMO) analysis, molecular electrostatic potential (MEP), natural bond orbital (NBO) analysis and nonlinear optical (NLO) property were accomplished by density functional theory (DFT) at B3LYP level with 6-311G(d,p)/aug-cc-pVTZ-PP basis set. Preliminary determination of antitumor activity and lipophilicity of this metal complex was performed experimentally and the promising results were obtained. This encouraged us to study the interaction and binding mode/modes of this complex with DNA as the primary receptor for the chemotropic drugs and BSA as the transporter protein in the circulatory system. For this reason, the binding of newly made complex was assessed in-vitro under physiological state using experimental and in-silico molecular modeling studies. So, the CT-DNA binding study of this complex was explored using spectrofluorometric as well as spectrophotometric techniques, viscosity and gel electrophoresis experiments. Furthermore, fluorescence, UV-Vis, F[Formula: see text]rster resonance energy transfer and circular dichroism studies were carried out for BSA binding. The experimental and computational interaction studies showed that [Pd(1, 3-pn)(acac)]Cl complex binds to the minor groove of CT-DNA and interacts with BSA by van der Waals forces and hydrogen bond.

Comparative NMR metabolomics of the responses of A2780 human ovarian cancer cells to clinically established Pt-based drugs

Pt-based drugs play a very important role in current cancer treatments; yet, their cellular and mechanistic aspects are not fully understood. NMR metabolomics provides a powerful tool to investigate the...

TTK is a potential therapeutic target for cisplatin-resistant ovarian cancer

Background

Drug resistance and recurrence are main contributors to the poor prognosis of ovarian cancer. Cisplatin is a platinum compound which is widely used in the treatment of various solid tumors including ovarian cancer. Up to now, the mechanism of cisplatin resistance in ovarian cancer is unclear. Threonine and tyrosine kinase (TTK), an integral part of the spindle assembly checkpoint, may be a potential new target associated with chemotherapy sensitivity.

Results

TTK was up-regulated in the cisplatin-resistant ovarian cancer cell line. Down-regulation of TTK could recover the sensitivity of cisplatin-resistant ovarian cancer cells to cisplatin treatment. Mechanistically, the PI3K/AKT signaling pathway was activated in cisplatin-resistant cells, and this pathway would be affected by TTK expression. Furthermore, TTK was highly expressed in the tissues of ovarian cancer patients, especially those acquired resistance to cisplatin.

Conclusions

Our study revealed that TTK may be a promising therapeutic target for cisplatin-resistant ovarian cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-021-00884-z.

Synchrotron-Based Fourier-Transform Infrared Micro-Spectroscopy (SR-FTIRM) Fingerprint of the Small Anionic Molecule Cobaltabis(dicarbollide) Uptake in Glioma Stem Cells

The anionic cobaltabis (dicarbollide) [3,3'-Co(1,2-C2B9H11)2]-, [o-COSAN]-, is the most studied icosahedral metallacarborane. The sodium salts of [o-COSAN]- could be an ideal candidate for the anti-cancer treatment Boron Neutron Capture Therapy (BNCT) as it possesses the ability to readily cross biological membranes thereby producing cell cycle arrest in cancer cells. BNCT is a cancer therapy based on the potential of 10B atoms to produce α particles that cross tissues in which the 10B is accumulated without damaging the surrounding healthy tissues, after being irradiated with low energy thermal neutrons. Since Na[o-COSAN] displays a strong and characteristic ν(B-H) frequency in the infrared range 2.600-2.500 cm-1, we studied the uptake of Na[o-COSAN] followed by its interaction with biomolecules and its cellular biodistribution in two different glioma initiating cells (GICs), mesenchymal and proneural respectively, by using Synchrotron Radiation-Fourier Transform Infrared (FTIR) micro-spectroscopy (SR-FTIRM) facilities at the MIRAS Beamline of ALBA synchrotron light source. The spectroscopic data analysis from the bands in the regions of DNA, proteins, and lipids permitted to suggest that after its cellular uptake, Na[o-COSAN] strongly interacts with DNA strings, modifies proteins secondary structure and also leads to lipid saturation. The mapping suggests the nuclear localization of [o-COSAN]-, which according to reported Monte Carlo simulations may result in a more efficient cell-killing effect compared to that in a uniform distribution within the entire cell. In conclusion, we show pieces of evidence that at low doses, [o-COSAN]- translocates GIC cells' membranes and it alters the physiology of the cells, suggesting that Na[o-COSAN] is a promising agent to BNCT for glioblastoma cells.

Response of Osteosarcoma Cell Metabolism to Platinum and Palladium Chelates as Potential New Drugs

This paper reports the first metabolomics study of the impact of new chelates Pt2Spm and Pd2Spm (Spm = Spermine) on human osteosarcoma cellular metabolism, compared to the conventional platinum drugs cisplatin and oxaliplatin, in order to investigate the effects of different metal centers and ligands. Nuclear Magnetic Resonance metabolomics was used to identify meaningful metabolite variations in polar cell extracts collected during exposure to each of the four chelates. Cisplatin and oxaliplatin induced similar metabolic fingerprints of changing metabolite levels (affecting many amino acids, organic acids, nucleotides, choline compounds and other compounds), thus suggesting similar mechanisms of action. For these platinum drugs, a consistent uptake of amino acids is noted, along with an increase in nucleotides and derivatives, namely involved in glycosylation pathways. The Spm chelates elicit a markedly distinct metabolic signature, where inverse features are observed particularly for amino acids and nucleotides. Furthermore, Pd2Spm prompts a weaker response from osteosarcoma cells as compared to its platinum analogue, which is interesting as the palladium chelate exhibits higher cytotoxicity. Putative suggestions are discussed as to the affected cellular pathways and the origins of the distinct responses. This work demonstrates the value of untargeted metabolomics in measuring the response of cancer cells to either conventional or potential new drugs, seeking further understanding (or possible markers) of drug performance at the molecular level.

Metallodrug-protein interaction probed by synchrotron terahertz and neutron scattering spectroscopy

This experimental work applied coherent synchrotron-radiation terahertz spectroscopy and inelastic neutron scattering to address two processes directly associated with the mode of action of metal-based anticancer agents that can severely undermine chemotherapeutic treatment: drug binding to human serum albumin, occurring during intravenous drug transport, and intracellular coordination to thiol-containing biomolecules (such as metallothioneins) associated with acquired drug resistance. Cisplatin and two dinuclear platinum (Pt)- and palladium (Pd)-polyamine agents developed by this research group, which have yielded promising results toward some types of human cancers, were investigated. Complementary synchrotron-radiation-terahertz and inelastic neutron scattering data revealed protein metalation, through S- and N-donor ligands from cysteine, methionine, and histidine residues. A clear impact of the Pt and Pd agents was evidenced, drug binding to albumin and metallothionein having been responsible for significant changes in the overall protein conformation, as well as for an increased flexibility and possible aggregation.

Overexpression of miR-329-3p sensitizes osteosarcoma cells to cisplatin through suppression of glucose metabolism by targeting LDHA

Osteosarcoma (OS) is one of the most frequent malignant bone tumor types. Traditional treatments of OS involve standard chemotherapy or combination with radiation before and after surgery. Cisplatin is one of the most effective chemotherapeutic drugs used for treating osteosarcoma. However, patients with advanced tumor stages develop cisplatin resistance, leading to a major clinical challenge. In this study, we investigated the roles of miR-329-3p in cisplatin sensitivity of osteosarcoma cells. We found miR-329-3p was significantly downregulated in osteosarcoma tissues compared with normal bone tissues. Overexpression of miR-329-3p suppressed osteosarcoma cell proliferation. Moreover, we observed low-toxic cisplatin treatments suppressed miR-329-3p but higher concentrations of cisplatin-induced miR-329-3p expression. In addition, miR-329-3p was significantly downregulated in cisplatin-resistant Saos-2 cells which displayed elevated glucose metabolism. Overexpression of miR-329-3p significantly impaired glucose metabolism of Saos-2 cells. Bioinformatics analysis and luciferase assay consistently demonstrated the glycolysis enzyme, lactate dehydrogenase-A (LDHA) was a direct target of miR-329-3p in osteosarcoma cells. Rescue experiments revealed restoration of LDHA in miR-329-3p-overexpressed cisplatin-resistant cells effectively recovered glucose metabolism, resulting in increased cisplatin resistance. This study demonstrates a miR-329-3p-LDHA-glucose metabolism-cisplatin resistance axis in osteosarcoma cells, providing a miRNA-based therapeutic strategy against chemoresistant osteosarcoma.

Metabolic Aspects of Palladium(II) Potential Anti-Cancer Drugs

This mini-review reports on the existing knowledge of the metabolic effects of palladium [Pd(II)] complexes with potential anticancer activity, on cell lines and murine models. Most studies have addressed mononuclear Pd(II) complexes, although increasing interest has been noted in bidentate complexes, as polynuclear structures. In addition, the majority of records have reported in vitro studies on cancer cell lines, some including the impact on healthy cells, as potentially informative in relation to side effects. Generally, these studies address metabolic effects related to the mechanisms of induced cell death and antioxidant defense, often involving the measurement of gene and protein expression patterns, and evaluation of the levels of reactive oxygen species or specific metabolites, such as ATP and glutathione, in relation to mitochondrial respiration and antioxidant mechanisms. An important tendency is noted toward the use of more untargeted approaches, such as the use of omic sciences e.g., proteomics and metabolomics. In the discussion section of this mini-review, the developments carried out so far are summarized and suggestions of possible future developments are advanced, aiming at recognizing that metabolites and metabolic pathways make up an important part of cell response and adaptation to therapeutic agents, their further study potentially contributing valuably for a more complete understanding of processes such as biotoxicity or development of drug resistance.

A New Look into the Mode of Action of Metal-Based Anticancer Drugs

The mode of action of Pt- and Pd-based anticancer agents (cisplatin and Pd₂Spm) was studied by characterising their impact on DNA. Changes in conformation and mobility at the molecular level in hydrated DNA were analysed by quasi-elastic and inelastic neutron scattering techniques (QENS and INS), coupled to Fourier transform infrared (FTIR) and microRaman spectroscopies. Although INS, FTIR and Raman revealed drug-triggered changes in the phosphate groups and the double helix base pairing, QENS allowed access to the nanosecond motions of the biomolecule’s backbone and confined hydration water within the minor groove. Distinct effects were observed for cisplatin and Pd₂Spm, the former having a predominant effect on DNA’s spine of hydration, whereas the latter had a higher influence on the backbone dynamics. This is an innovative way of tackling a drug’s mode of action, mediated by the hydration waters within its pharmacological target (DNA).

Chemotherapeutic Targets in Osteosarcoma: Insights from Synchrotron-MicroFTIR and Quasi-Elastic Neutron Scattering

This study aimed at the development of improved drugs against human osteosarcoma, which is the most common primary bone tumor in children and teenagers with a low prognosis. New insights into the impact of an unconventional Pd(II) anticancer agent on human osteosarcoma cells were obtained by synchrotron radiation-Fourier transform infrared microspectroscopy and quasi-elastic neutron scattering (QENS) experiments from its effect on the cellular metabolism to its influence on intracellular water, which can be regarded as a potential secondary pharmacological target. Specific infrared biomarkers of drug action were identified, enabling a molecular-level description of variations in cellular biochemistry upon drug exposure. The main changes were detected in the protein and lipid cellular components, namely, in the ratio of unsaturated-to-saturated fatty acids. QENS revealed reduced water mobility within the cytoplasm for drug-treated cells, coupled to a disruption of the hydration layers of biomolecules. Additionally, the chemical and dynamical profiles of osteosarcoma cells were compared to those of metastatic breast cancer cells, revealing distinct dissimilarities that may influence drug activity.

Adsorbed States of Hydrogen on Platinum: A New Perspective

The interaction of hydrogen with platinum is enormously important in many areas of catalysis. The most significant of these are in polymer electrolyte membrane fuel cells (PEMFC), in which carbon‐supported platinum is used to dissociate hydrogen gas at the anode. The nature of adsorbed hydrogen on platinum has been studied for many years on single‐crystal surfaces, on high‐surface area‐platinum metal (Raney platinum and platinum black), and on supported catalysts. Many forms of vibrational spectroscopy have played a key role in these studies, however, there is still no clear consensus as to the assignment of the spectra. In this work, ab initio molecular dynamics (AIMD) and lattice dynamics were used to study a 1.1 nm nanoparticle, Pt₄₄H₈₀. The results were compared to new inelastic neutron scattering spectra of hydrogen on platinum black and of a carbon‐supported platinum fuel cell catalyst and an assignment scheme that rationalises all previous data is proposed.

Neuroprotective Role of Selected Antioxidant Agents in Preventing Cisplatin-Induced Damage of Human Neurons In Vitro

Chemotherapy-induced peripheral neuropathy (CIPN) is a side effect of platinum-based chemotherapy and decreases the quality of life of cancer patients. We compared neuroprotective properties of several agents using an in vitro model of terminally differentiated human cells NT2-N derived from cell line NT2/D1. Sodium azide and an active metabolite of amifostine (WR1065) increase cell viability in simultaneous treatment with cisplatin. In addition, WR1065 protects the non-dividing neurons by decreasing cisplatin caused oxidative stress and apoptosis. Accumulation of Pt in cisplatin-treated cells was heterogeneous, but the frequency and concentration of Pt in cells were lowered in the presence of WR1065 as shown by X-ray fluorescence microscopy (XFM). Transition metals accumulation accompanied Pt increase in cells; this effect was equally diminished in the presence of WR1065. To analyze possible chemical modulation of Pt-DNA bonds, we examined the platinum L_III near edge spectrum by X-ray absorption spectroscopy. The spectrum found in cisplatin-DNA samples is altered differently by the addition of either WR1065 or sodium azide. Importantly, a similar change in Pt edge spectra was noted in cells treated with cisplatin and WR1065. Therefore, amifostine should be reconsidered as a candidate for treatments that reduce or prevent CIPN.

Anticancer activity of palladium-based complexes against triple-negative breast cancer

Treatment of triple-negative breast carcinoma (TNBC) remains an unmet medical need with no targeted therapy available to date. Accounting for 10-30% of all human breast cancer tumors, this mammary carcinoma subtype has a particularly poor prognosis owing to its high metastatic potential, aggressive biology and limited pharmacological treatment options. Platinum chemotherapeutics are the mainstay therapy in patients with TNBC but their clinical use is limited by severe toxicity and acquired resistance. Palladium-based complexes are appealing alternative metal-based drugs because of significant similarities regarding structure and coordination chemistry with the platinum agents. This review summarizes the knowledge gathered so far on 121 Pd(II) complexes, emphasizing their anticancer activity and putative pharmacological targets toward TNBC.

Anticancer drug impact on DNA – a study by neutron spectroscopy coupled with synchrotron-based FTIR and EXAFS

Complementary information on drug–DNA interplay has been achieved for Pt/Pd anticancer agents, by a combined QENS, SR-FTIR-ATR and EXAFS approach.

Redox-responsive cisplatin nanogels for anticancer drug delivery

Inspired by cisplatin's deactivation by glutathione (GSH) in cancer, a GSH responsive nanogel loaded with doxorubicin (Dox) was prepared using hyaluronan as a matrix and cisplatin as a crosslinker. The elevated GSH depletes the cisplatin crosslinker in the nanogel, enhances Dox release and boosts cytotoxicity, thus providing a new GSH responsive platform to reverse cisplatin resistance.

Novel platinum-based anticancer drug: a complete vibrational study

The introduction of cisplatin to oncology, in the 1970s, marked the onset of the search for novel and improved metal-based anticancer drugs. Polynuclear PtII and PdII complexes with linear alkylamines as bridging ligands are a class of potential antineoplastic agents that have shown promising cytotoxicity against low-prognosis human cancers, such as metastatic breast adenocarcinoma and osteosarcoma. The present study reports an analysis of [μ-N,N′-bis(3-aminopropyl)butane-1,4-diamine-κ4 N,N′:N′′,N′′′]bis[dichloridoplatinum(II)], [Pt2Cl4(C10H26N4)], denoted Pt2Spm (Spm is spermine), by vibrational spectroscopy coupled to theoretical calculations. Within the latter, the Density Functional Theory (DFT – mPW1PW/6-31G*) and Effective Core Potential (ECP – LANL2DZ) approaches were used, in order to ensure the most accurate representation of the molecule and achieve a maximum agreement with the experimental data. The solid-state geometry of Pt2Spm corresponds to Ci symmetry, displaying 132 vibrational modes. A complete assignment of the experimental vibrational profile of the system was attained through the combined application of complementary Raman, FT–IR and Inelastic Neutron Scattering (INS) techniques. INS allowed an unequivocal identification of the CH2 and NH2 rocking modes, not clearly detected by the optical techniques, while Raman measurements led to a clear discrimination of the Pt—N stretching frequencies from the two distinct Pt—N moieties within the chelate. The metal-to-metal distances calculated for the molecule under study were found to allow the establishment of effective inter- and intrastrand crosslinks with DNA. These results will hopefully help to clarify the mode of action of the compound, at the molecular level, contributing to the development of improved cisplatin-like chemotherapeutic drugs having a higher efficacy and specificity coupled to lower acquired resistance and deleterious side effects.

Chemotherapeutic response to cisplatin-like drugs in human breast cancer cells probed by vibrational microspectroscopy

Studies of drug-cell interactions in cancer model systems are essential in the preclinical stage of rational drug design, which relies on a thorough understanding of the mechanisms underlying cytotoxic activity and biological effects, at a molecular level. This study aimed at applying complementary vibrational spectroscopy methods to evaluate the cellular impact of two Pt(ii) and Pd(ii) dinuclear chelates with spermine (Pt2Spm and Pd2Spm), using cisplatin (cis-Pt(NH3)2Cl2) as a reference compound. Their effects on cellular metabolism were monitored in a human triple-negative metastatic breast cancer cell line (MDA-MB-231) by Raman and synchrotron-radiation infrared microspectroscopies, for different drug concentrations (2-8 μM) at 48 h exposure. Multivariate data analysis was applied (unsupervised PCA), unveiling drug- and concentration-dependent effects: apart from discrimination between control and drug-treated cells, a clear separation was obtained for the different agents studied - mononuclear vs. polynuclear, and Pt(ii) vs. Pd(ii). Spectral biomarkers of drug action were identified, as well as the cellular response to the chemotherapeutic insult. The main effect of the tested compounds was found to be on DNA, lipids and proteins, the Pd(ii) agent having a more significant impact on proteins while its Pt(ii) homologue affected the cellular lipid content at lower concentrations, which suggests the occurrence of distinct and unconventional pathways of cytotoxicity for these dinuclear polyamine complexes. Raman and FTIR microspectroscopies were confirmed as powerful non-invasive techniques to obtain unique spectral signatures of the biochemical impact and physiological reaction of cells to anticancer agents.

Intracellular water – an overlooked drug target? Cisplatin impact in cancer cells probed by neutrons

Intracellular water as a secondary pharmacological target?

Anti-Invasive and Anti-Proliferative Synergism between Docetaxel and a Polynuclear Pd-Spermine Agent

The present work is aimed at evaluating the antitumour properties of a Pd(II) dinuclear complex with the biogenic polyamine spermine, by investigating: i) the anti-angiogenic and anti-migration properties of a Pd(II) dinuclear complex with spermine (Pd2Spm); ii) the anti-proliferative activity of Pd2Spm against a triple negative human breast carcinoma (MDA-MB-231); and finally iii) the putative interaction mediated by combination of Pd2Spm with Docetaxel. Anti-invasive (anti-angiogenic and anti-migratory) as well as anti-proliferative capacities were assessed, for different combination schemes and drug exposure times, using the CAM assay and VEGFR2 activity measurement, the MatrigelTM method and the SRB proliferation test. The results thus obtained evidence the ability of Pd2Spm to restrict angiogenesis and cell migration: Pd2Spm induced a marked inhibition of migration (43.8±12.2%), and a higher inhibition of angiogenesis (81.8±4.4% for total length values, at 4 μM) as compared to DTX at the clinical dosage 4x10-2 μM (26.4±14.4%; n = 4 to 11). Combination of Pd2Spm/DTX was more effective as anti-invasive and anti-proliferative than DTX or Pd2Spm in sole administration, which is compatible with the occurrence of synergism: for the anti-angiogenic effect, IC50(Pd2Spm/DTX) = 0.5/0.5x10-2 μM vs IC50(DTX) = 1.7x10-2 μM and IC50(Pd2Spm) = 1.6 μM. In conclusion, the reported effects of Pd2Spm on angiogenesis, migration and proliferation showed that this compound is a promising therapeutic agent against this type of breast cancer. Moreover, combined administration of Pd2Spm and DTX was found to trigger a substantial synergetic effect regarding angiogenesis inhibition as well as anti-migratory and anti-proliferative activities reinforcing the putative use of Pd(II) complexes in chemotherapeutic regimens. This is a significant outcome, aiming at the application of these combined strategies towards metastatic breast cancer (or other type of resistant cancers), justifying further studies that include pre-clinical trials.

Molecular dynamics simulation and free energy analysis of the interaction of platinum-based anti-cancer drugs with DNA

Cisplatin and oxaliplatin are two widely-used anti-cancer drugs which covalently bind to a same location in DNA strands. Platinum agents make intrastrand and interstrand cross-links with the N7 atoms of guanine nucleotides which prevent DNA from polymerization by causing a distortion in the double helix. Molecular dynamics simulations and free energy calculations were carried out to investigate the binding of two platinum-based anti-cancer drugs with DNA. We compared the binding of these drugs which differ in their carrier ligands, and hence their potential interactions with DNA. When a platinum agent binds to nucleotides, it causes a high amount of deformation in DNA structure. To find the extent of deformation, torsion angles and base pair and groove parameters of DNA were considered. These parameters were compared with normal B-DNA which was considered as the undamaged DNA. The formation of hydrogen bonds between drugs and DNA nucleotides was examined in solution. It was shown that oxaliplatin forms more hydrogen bonds than cisplatin. Our results confirm that the structure of the platinated DNA rearranges significantly and cisplatin tries to deform DNA more than oxaliplatin. The binding free energies were also investigated to understand the affinities, types and the contributions of interactions between drugs and DNA. It was concluded that oxaliplatin tendency for binding to DNA is more than cisplatin in solvent environment. The binding free energy was calculated based on the MM/PBSA and MM/GBSA methods and the results of QM/MM calculations verified them.

Combined treatment of epigallocatechin gallate and Coenzyme Q10 attenuates cisplatin-induced nephrotoxicity via suppression of oxidative/nitrosative stress, inflammation and cellular damage

Cisplatin (CP), a platinum based anticancer drug is used as one of the first-line therapy for the treatment of different types of solid tumors. However, CP-induced side effects particularly, nephrotoxicity is a major concern. A single nephrotoxic dose (7 mg/kg body weight) of CP was administered in rats with or without, pre and post combined multidoses of epigallocatechin gallate (EGCG) and coenzyme Q10 (CoQ10) (15 and 5 mg/kg body weight respectively). CP administration resulted in marked increase in the nephrotoxic parameters with alterations in the oxidative and nitrosative stress markers. The concentration of inflammatory, as well as apoptotic markers were markedly up-regulated in the kidney of the CP-treated group. Furthermore, CP resulted in histological injury in the renal tissues. Combined antioxidant treatment significantly (p < 0.01) attenuated CP-induced oxidative stress, nitrosative stress, inflammatory and apoptotic parameters. Moreover, an improvement in the histopathological changes confirmed the nephroprotective effect of antioxidant treatment. In conclusion, our study indicates that the combinatorial multidoses of EGCG and CoQ10 ameliorate the cisplatin-mediated pathogenesis by improving renal oxidative/nitrosative status, inflammation and apoptosis and thus can be used as a promising protective agent to increase the efficacy of the drug by minimizing its major side effect i.e. nephrotoxicity.

Conformational study and reassessment of the vibrational assignments for Norspermidine

The present study presents and discusses the conformational preferences of Norspermidine (NSpd). The effects of varying the dielectric constant on the conformational preferences are discussed, with a view to infer which conformation will correspond to the most stable in the pure condensed liquid phase. Within the same context, a set of NSpd-NH3 molecular adducts were simulated in order to determine the relevance of intermolecular hydrogen bonding on the overall stability and relative positioning of the respective vibrational frequencies. The calculations presently performed allowed a reassessment of the vibrational assignments for NSpd. A full assignment of the NSpd vibrational spectra is presented, with special emphasis being given to the vibrational modes that proved to be most affected by hydrogen bonding. The various inconsistencies of a prior study found in the literature were identified and rectified.

On the correction of calculated vibrational frequencies for the effects of the counterions - α,ω-diamine dihydrochlorides

The present work provides sets of correction factors to adjust the calculated vibrational frequencies of a series of α,ω-diamines hydrochloride salts to account for the intermolecular interactions with the counterion. The study was performed using different theory levels for predicting the vibrational data of isolated dicationic α,ω-diamines and their hydrochloride forms, with and without the explicit account of the interactions with the chloride counterions. Different sets of correction factors were determined for each theory level considering the four smallest elements for the α,ω-diamines series, while their transferability and reliability was evaluated considering the larger elements of the series. The theory level simplification was also evaluated and was found to neither compromise the vibrational frequencies estimates nor the magnitude and accuracy of the pre-defined scaling factors. This suggests that transferability of the correction factors is possible not only for different diamines but also between different levels of theory with the averaged group correction factor, ζ g (a) , being the best choice to account for the effects of the N-H · · · Cl interactions. The possibility of simplifying the theory level without compromising efficiency and accuracy is additionally of utmost importance. This computational approach can constitute a valuable tool in the future for studying the hydrochloride forms of larger and more complex diamine systems. Graphical Abstract A computational approach that may constitute a valuable tool for studying the hydrochloride forms of large and complex diamine systems. Correction factors to adjust the vibrational frequencies calculated for isolated dicationic primary diamines for the effects of the interactions with chloride counterions, without their explicit account in the calculations, are presented and evaluated for eficiency.