Cisplatin, glutathione and the third wheel: a copper-(1,10-phenanthroline) complex modulates cisplatin-GSH interactions from antagonism to synergism in cancer cells resistant to cisplatin

DNA Damage Response Network and Intracellular Redox Status in the Clinical Outcome of Patients with Lung Cancer

Background/Objectives: DNA damage response (DDR) is a network of molecular pathways associated with the pathogenesis and progression of several diseases, as well as the outcome of chemotherapy. Moreover, the intracellular redox status is essential for maintaining cell viability and controlling cellular signaling. Herein, we analyzed DDR signals and redox status in peripheral blood mononuclear cells (PBMCs) from patients with lung cancer with different response rates to platinum-based chemotherapy. Methods: Several DDR-associated signals and redox status, expressed as the GSH/GSSG ratio, were measured in two lung cancer cell lines (A549, H1299), two normal fibroblast cell lines (WS1, 1BR3hT), and PBMCs from 20 healthy controls and 32 patients with lung cancer at baseline (17 responders and 15 non-responders to subsequent platinum-based chemotherapy). Results: Higher levels of endogenous/baseline DNA damage, decreased GSH/GSSG ratios, and augmented apurinic/apyrimidinic sites, as well as lower nucleotide excision repair (NER) and increased interstrand cross-links (ICLs) repair efficiencies, were observed in lung cancer cell lines compared with normal ones (all p < 0.05). Moreover, PBMCs from patients with lung cancer showed reduced GSH/GSSG ratios, augmented apurinic/apyrimidinic sites, decreased NER and ICL repair capacities, and lower apoptosis rates, compared with healthy controls (all p < 0.001). Interestingly, PBMCs from patients who are responders are characterized by reduced GSH/GSSG ratios, augmented apurinic/apyrimidinic sites, decreased NER and ICL repair capacities, and higher apoptosis rates compared with patients who are non-responders (all p < 0.01). Conclusions: Together, DDR-associated parameters and redox status measured in PBMCs from patients with lung cancer at baseline are associated with the therapeutic benefit of platinum-based chemotherapy.

Core-shell cisplatin/SiO2 nanocapsules combined with PTC-209 overcome chemotherapy-Acquired and intrinsic resistance in hepatocellular carcinoma

The primary cause of cisplatin resistance in liver cancer is reduced intracellular drug accumulation and altered DNA repair/apoptosis signaling. Existing strategies to reverse cisplatin resistance have limited efficacy, as they target individual factors. This study proposes a drug delivery system consisting of a cisplatin core, a silica shell with a tetra-sulfide bond, and a PEG-coated surface (Core/shell-PGCN). The system is designed to consume glutathione (GSH) and reduce cisplatin excretion from cells, thereby overcoming acquired cisplatin resistance. In addition, Core/shell-PGCN incorporates PTC-209 (Core/shell-PGCN@PTC-209), a Bmi1 inhibitor that suppresses liver cancer stem cells (CSC), to mitigate DNA repair/apoptosis signaling and reverse intrinsic cisplatin resistance. In vivo and in vitro results demonstrate that Core/shell-PGCN@PTC-209 can comprehensively regulate GSH and CSC, reverse intrinsic and acquired cisplatin resistance, and enhance the efficacy of cisplatin in treating liver cancer. This "inner cultivation, outer action" approach may offer a new strategy for reversing cisplatin resistance in liver cancer. STATEMENT OF SIGNIFICANCE: Cisplatin resistance is widely observed in liver cancer (HCC) chemotherapy, with two mechanisms identified: acquired and intrinsic. Most strategies aimed at overcoming cisplatin resistance focus on a single perspective. This study introduces a core-shell drug delivery system (DDS) combined with HCC stem cell inhibitors, which can effectively address cisplatin resistance in HCC by targeting both acquisition and internality. Specifically, the core-shell drug delivery system can impede cisplatin efflux by neutralizing the acquired resistance factor (GSH), thus overcoming acquired resistance. Additionally, HCC stem cell inhibitors can reverse intrinsic resistance by inhibiting HCC stem cells. Therefore, this study contributes to the application of DDS in combating drug resistance in HCC and enhances its potential for clinical implementation.

Reducing Chemotherapy-Induced DNA Damage via nAChR-Mediated Redox Reprograming-A New Mechanism for SCLC Chemoresistance Boosted by Nicotine

Up to 60% of patients with small cell lung cancer (SCLC) continue to smoke, which is associated with worse clinical outcomes. Platinum-based chemotherapies, in combination with topoisomerase inhibitors, are first-line therapies for SCLC, with rapid chemoresistance as a major barrier. We provided evidence in this study that nicotine and its major metabolite, cotinine, at physiologically relevant concentrations, reduced the efficacy of platinum-based chemotherapies and facilitated chemoresistance in SCLC cells. Mechanistically, nicotine or cotinine reduced chemotherapy-induced DNA damage by modulating cellular redox processes, with nAChRs as the upstream targets. Surprisingly, cisplatin treatment alone also increased the levels of nAChRs in SCLC cells, which served as a self-defense mechanism against platinum-based therapies. These discoveries were confirmed in long-term in vitro and in vivo studies. Collectively, our results depicted a novel and clinically important mechanism of chemoresistance in SCLC treatment: nicotine exposure significantly compromises the efficacy of platinum-based chemotherapies in SCLC treatment by reducing therapy-induced DNA damage and accelerating chemoresistance acquisition. The results also emphasized the urgent need for tobacco cessation and the control of NRT use for SCLC management.

Copper(II) Phenanthroline-Based Complexes as Potential AntiCancer Drugs: A Walkthrough on the Mechanisms of Action

Copper is an endogenous metal ion that has been studied to prepare a new antitumoral agent with less side-effects. Copper is involved as a cofactor in several enzymes, in ROS production, in the promotion of tumor progression, metastasis, and angiogenesis, and has been found at high levels in serum and tissues of several types of human cancers. Under these circumstances, two strategies are commonly followed in the development of novel anticancer Copper-based drugs: the sequestration of free Copper ions and the synthesis of Copper complexes that trigger cell death. The latter strategy has been followed in the last 40 years and many reviews have covered the anticancer properties of a broad spectrum of Copper complexes, showing that the activity of these compounds is often multi factored. In this work, we would like to focus on the anticancer properties of mixed Cu(II) complexes bearing substituted or unsubstituted 1,10-phenanthroline based ligands and different classes of inorganic and organic auxiliary ligands. For each metal complex, information regarding the tested cell lines and the mechanistic studies will be reported and discussed. The exerted action mechanisms were presented according to the auxiliary ligand/s, the metallic centers, and the increasing complexity of the compound structures.

Structure elucidation, in vitro binding studies and ROS-dependent anti-cancer activity of Cu(II) and Zn(II) phthaloylglycinate(phen) complexes against MDA-MB-231 cells

New mononuclear Cu(II) and Zn(II)-based complexes 1 [Cu(L)2(diimine)HOCH3] and 2 [Zn(L)2(diimine)] have been synthesized as anti-cancer chemotherapeutics targeted to tRNA. The structure elucidation of complexes 1 and 2 was carried out by spectroscopic and single X-ray diffraction studies. In vitro interaction studies of complexes 1 and 2 with ct-DNA/tRNA were performed by employing various biophysical techniques to evaluate and predict their interaction behavior and preferential selectivity at biomolecular therapeutic targets. The corroborative results of the interaction studies demonstrated that complexes 1 and 2 exhibited avid binding propensity via intercalative mode of binding toward ct-DNA/tRNA. Electrophoretic assay revealed that the complexes 1 and 2 were able to promote single- and double-strand cleavage of the plasmid DNA at low micromolar concentrations under physiological conditions in the absence of an additional oxidizing or reducing agent. RNA hydrolysis studies revealed that the complexes 1 and 2 could promote tRNA cleavage in a concentration and time-dependent manner. The cytotoxic potential of complexes 1 and 2 was evaluated against the MDA-MB-231 cell line, which showed that the complexes were able to inhibit the cell growth in a dose-dependent manner. The intracellular ROS production and mitochondrial superoxide anion assay revealed that the complexes 1 and 2 induce a dose-dependent activity, suggesting the involvement of ROS-mediated mitochondrial apoptotic pathway leading to cell death.

The first copper(ii) complex with 1,10-phenanthroline and salubrinal with interesting biochemical properties

The novel copper complex [Cu(phen)2(salubrinal)](ClO4)2 (C0SAL) has been synthesised and characterised. Copper(ii) is coordinated by salubrinal through the thionic group, as shown by the UV-Vis, IR, ESI-MS and tandem mass results, together with the theoretical calculations. The formed complex showed a DPPH radical scavenging ability higher than that of salubrinal alone. Studies on lipid oxidation inhibition showed that the C0SAL concentration, required to inhibit the enzyme, was lower than that of salubrinal. The inhibition of the enzyme could take place via allosteric modulation, as suggested by docking calculations. C0SAL showed a good cytotoxic activity on A2780 cells, 82 fold higher than that of the precursor salubrinal and 1.4 fold higher than that of [Cu(phen)2(H2O)](ClO4)2. Treatment with C0SAL in SKOV3 ovarian cancer cells induced expression of GRP-78 and DDIT3 regulators of ER-stress response. The cytotoxic effect of C0SAL was reverted in the presence of TUDCA, suggesting that C0SAL induces cell death through ER-stress. In A2780 cells treated with C0SAL γ-H2AX was accumulated, suggesting that DNA damage was also involved.

Supraamphiphilic Systems Based on Metallosurfactant and Calix[4]resorcinol: Self-Assembly and Drug Delivery Potential

Metallic amphiphiles are used as building blocks in the construction of nanoscale superstructures, where the hydrophobic effects induce the self-assembly of the nanoparticles of interest. However, the influence of synergizing multiple chemical interactions on an effective design of these structures mostly remains an open question. In this regard, supraamphiphilic systems based on flexible surfactant molecules and rigid macrocycles are being actively developed, but there are few works on the interaction between metallosurfactants and macrocycles. In the present work, the self-assembly and biological properties of a metallosurfactant with calixarene were studied for the first time. The metallosurfactant, a complex between lanthanum nitrate and two 4-aza-1-hexadecylazoniabicyclo[2.2.2]octane bromide units, and calix[4]resorcinol containing sulfonate groups on the upper rim were used to form a novel supraamphiphilic composition. The system formed was studied using a variety of physicochemical methods, including spectrophotometry, NMR, XRF, and dynamic and electrophoretic light scattering. It was found that the most optimal tetraanionic calix[4]resorcinol to dicationic metallosurfactant molar ratio, leading to mixed aggregation upon ion pair complexation, is 2:3. The mixed aggregates formed in the pentamolar concentration range were able to encapsulate hydrophilic substrates, including the anticancer drug cisplatin, the pure form of which is more cytotoxic toward healthy cells than toward diseased cells. Interestingly, the drug loaded into the macrocycle-metallosurfactant particles was less cytotoxic to a healthy Chang liver cell line and more cytotoxic to tumor M-HeLa cells. This selectivity depends on the amount of cisplatin added. The more drug is added to the macrocycle-metallosurfactant composition, the greater the biological activity against cancer cells. Taking into account that the appearance of resistance of cancer cells to drugs, especially to cisplatin, is one of the most important problems in treatment, the results of this work envisage the potential application of a mixed macrocycle-metallosurfactant system for the design of therapeutic cisplatin compositions.

SynergyFinder 2.0: visual analytics of multi-drug combination synergies

SynergyFinder (https://synergyfinder.fimm.fi) is a stand-alone web-application for interactive analysis and visualization of drug combination screening data. Since its first release in 2017, SynergyFinder has become a widely used web-tool both for the discovery of novel synergistic drug combinations in pre-clinical model systems (e.g. cell lines or primary patient-derived cells), and for better understanding of mechanisms of combination treatment efficacy or resistance. Here, we describe the latest version of SynergyFinder (release 2.0), which has extensively been upgraded through the addition of novel features supporting especially higher-order combination data analytics and exploratory visualization of multi-drug synergy patterns, along with automated outlier detection procedure, extended curve-fitting functionality and statistical analysis of replicate measurements. A number of additional improvements were also implemented based on the user requests, including new visualization and export options, updated user interface, as well as enhanced stability and performance of the web-tool. With these improvements, SynergyFinder 2.0 is expected to greatly extend its potential applications in various areas of multi-drug combinatorial screening and precision medicine.

A simultaneously GSH-depleted bimetallic Cu(ii) complex for enhanced chemodynamic cancer therapy

A bimetallic Cu(ii) complex was developed as a novel antitumor chemodynamic therapy agent with glutathione depletion properties.

Mixed copper(ii)–phenanthroline complexes induce cell death of ovarian cancer cells by evoking the unfolded protein response

There is an ongoing need for development of new therapeutics that override acquired resistance to cancer therapy. Targeting endoplasmic reticulum by Cu(ii)–phenanthroline complexes may represent such alternative strategy to current cytotoxic drugs.