Cytotoxicity, apoptosis, cell cycle arrest, reactive oxygen species, mitochondrial membrane potential, and Western blotting analysis of ruthenium(II) complexes

Beyond Chemistry: Investigating the Physical, Pharmacological, and Computational Aspects of Polyoxometalate Integrated Solid Lipid Nanoparticles for Cancer Treatment

Purpose

The solid lipid nanoparticles of transitional metal complexes (POMs) were prepared with natural lipids with the aim of developing a safer therapeutic approach for cancer treatment.

Methods

Natural lipids were used to create solid lipid nanoparticles containing transitional metal complexes (POMs).

Results

The nanoparticles had displayed appreciable entrapment and loading percentage of P5W30. The zeta capacitance was measured to be -32.57±6.44 mV with average particle dimension of 160.5±8.61 nm and polydispersity index (PDI) of around 0.3814±0.096. The effectiveness of P5W30-BW-SLNs in inhibiting the growth of HeLa cells was found to be higher (IC50 = 3.02±2.14 µg/mL) compared to pure P5W30 (IC50 = 7.93±5.08 µg/mL). Further examinations of DNA damage were made through comet test and flow cytometry techniques. The assessment of tumor regression and survival was conducted, and comparison was recorded. The P5W30-BW-SLNs resulted in a 72.91% increase in survival rates and a reduction in tumor burden by 2.967±0.543%. Moreover, the computational findings demonstrate a strong connection with the actual data, providing a plausible explanation for the notable chemopreventive efficacy of POM against HeLa cell lines.

Conclusion

The study's findings might pave the way for a more efficient delivery system in cancer treatment.

Endocytic Uptake of Self-Assembled Iridium(III) Nanoaggregates for Holistic Treatment of Metastatic 3D Triple-Negative Breast Tumor Spheroids

Triple-negative breast cancer (TNBC) presents a formidable challenge due to its aggressive behavior and limited array of treatment options available. This study focuses on employing nanoaggregate material of organometallic Ir(III) complexes for treating TNBC cell line MDA-MB-231. In this approach, Ir(III) complexes with enhanced cellular permeability are strategically designed and achieved through the incorporation of COOMe groups into their structure. The lead compound, IrL1, exhibits promiscuous nanoscale aggregation in RPMI cell culture media, characterized by a stable hydrodynamic effective diameter ranging from 190 to 202 nm over 48 h. With excellent photo-responsive contrast-enhanced cell imaging properties IrL1 exhibits an outstanding IC50, 48h value of 36.05± 0.03 nm when irradiated with 390 nm light in MDA-MB-231 (IC50, 48 h of Cisplatin is 5.29 µµ). In cell, investigation confirms that IrL1 nanoaggregates internalization via energy-dependent endocytosis undergo ferroptosis and ROS mediated cell death in MDA-MB-231 cells. Further, these in vivo studies using NOD-SCID mice confirmed that IrL1 exhibits a tendency to ablate tumors inoculated in mice models at therapeutically relevant doses. Thus, this comprehensive approach holds promise for expanding the repertoire of organometallic Ir(III) nanoaggregates with adaptable characteristics, thereby advancing their clinical utility of nanomedicine in the holistic treatment of metastatic 3D triple-negative breast tumor spheroids.

Synthesis, characterization, pharmacological and computational evaluation of hyaluronic acid modified chebulinic acid encapsulated chitosan nanocomposite for cancer therapy

The purpose of this study was to produce hyaluronic acid customized nanoparticles with chitosan for the delivery of chebulinic acid (CLA) to enhance its anticancer potential against breast cancer. A significant portion of CLA was encapsulated (89.72 ± 4.38 %) and loaded (43.15 ± 5.61 %) within hybrid nanoparticles. The colloidal hybrid nanoparticles demonstrated a polydispersity index (PDI) of about 0.379 ± 0.112, with zeta capacitance of 32.69 ± 5.12 (mV), and an average size of 115 ± 8 (nm). It was found that CLA-CT-HA-NPs had stronger anticancer effects on MCF-7 cells (IC50 = 8.18 ± 3.02 μM) than pure CLA (IC50 = 17.15 ± 5.11 μM). The initial cytotoxicity findings were supported by additional investigations based on comet assay and flow cytometry analysis. Tumor remission and survival were evaluated in five separate groups of mice. When juxtaposed with pure CLA (3.17 ± 0.419 %), CLA-CT-HA-NPs improved survival rates and reduced tumor burden by 3.76 ± 0.811(%). Furthermore, in-silico molecular docking investigations revealed that various biodegradable polymers had several levels of compatibility with CLA. The outcomes of this study might potentially served as an effective strategy for delivering drugs in the context of breast cancer therapy.

Fabrication and evaluation of anticancer potential of diosgenin incorporated chitosan-silver nanoparticles; in vitro, in silico and in vivo studies

The discovery of effective therapeutic approaches with minimum side effects and their tendency to completely eradicate the disease is the main challenge in the history of cancer treatment. Fenugreek (FGK) seeds are a rich source of phytochemicals, especially Diosgenin (DGN), which shows outstanding anticancer activities. In the present study, chitosan-silver nanoparticles (ChAgNPs) containing Diosgenin (DGN-ChAgNPs) were synthesized and evaluated for their anticancer activity against breast cancer cell line (MCF-7). For the physical characterization, the hydrodynamic diameter and zeta potential of DGN-ChAgNPs were determined to be 160.4 ± 12 nm and +37.19 ± 5.02 mV, respectively. Transmission electron microscopy (TEM) showed that nanoparticles shape was mostly round with smooth edges. Moreover, DGN was efficiently entrapped in nanoformulation with good entrapment efficacy (EE) of ~88 ± 4 %. The in vitro anti-proliferative activity of DGN-ChAgNPs was performed by sulforhodamine B (SRB) assay with promising inhibitory concentration of 6.902 ± 2.79 μg/mL. DAPI staining, comet assay and flow cytometry were performed to validate the anticancer potential of DGN-ChAgNPs both qualitatively and quantitatively. The percentage of survival rate and tumor reduction weight was evaluated in vivo in different groups of mice. Cisplatin was used as a standard anticancer drug. The DGN-ChAgNPs (12.5 mg/kg) treated group revealed higher percentage of survival rate and tumor reduction weight as compared to pure DGN treated group. These findings suggest that DGN-ChAgNPs could be developed as potential treatment therapy for breast cancer.

Increasing the π-Expansive Ligands in Ruthenium(II) Polypyridyl Complexes: Synthesis, Characterization, and Biological Evaluation for Photodynamic Therapy Applications

Lack of selectivity is one of the main issues with currently used chemotherapies, causing damage not only to altered cells but also to healthy cells. Over the last decades, photodynamic therapy (PDT) has increased as a promising therapeutic tool due to its potential to treat diseases like cancer or bacterial infections with a high spatiotemporal control. Ruthenium(II) polypyridyl compounds are gaining attention for their application as photosensitizers (PSs) since they are generally nontoxic in dark conditions, while they show remarkable toxicity after light irradiation. In this work, four Ru(II) polypyridyl compounds with sterically expansive ligands were studied as PDT agents. The Ru(II) complexes were synthesized using an alternative route to those described in the literature, which resulted in an improvement of the synthesis yields. Solid-state structures of compounds [Ru(DIP)2phen]Cl2 and [Ru(dppz)2phen](PF6)2 have also been obtained. It is well-known that compound [Ru(dppz)(phen)2]Cl2 binds to DNA by intercalation. Therefore, we used [Ru(dppz)2phen]Cl2 as a model for DNA interaction studies, showing that it stabilized two different sequences of duplex DNA. Most of the synthesized Ru(II) derivatives showed very promising singlet oxygen quantum yields, together with noteworthy photocytotoxic properties against two different cancer cell lines, with IC50 in the micro- or even nanomolar range (0.06-7 μM). Confocal microscopy studies showed that [Ru(DIP)2phen]Cl2 and [Ru(DIP)2TAP]Cl2 accumulate preferentially in mitochondria, while no mitochondrial internalization was observed for the other compounds. Although [Ru(dppn)2phen](PF6)2 did not accumulate in mitochondria, it interestingly triggered an impairment in mitochondrial respiration after light irradiation. Among others, [Ru(dppn)2phen](PF6)2 stands out for its very good IC50 values, correlated with a very high singlet oxygen quantum yield and mitochondrial respiration disruption.

Exploration of the Pharmacophore for Cytoskeletal Targeting Ruthenium Polypyridyl Complexes

Ruthenium(II) trisdiimine complexes of the formula, [Ru(dip)n (L-L)3-n ]2+ , where n=0-3; dip=4,7-diphenyl-1,10-phenanthroline; L-L=2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) were prepared and tested for cytotoxicity in two cell lines (H358, MCF7). Cellular uptake and subcellular localization were determined by harvesting treated cells and determining the ruthenium concentration in whole or fractionated cells (cytosolic, nuclear, mitochondrial/ ER/Golgi, and cytoskeletal proteins) by Ru ICP-MS. The logP values for the chloride salts of these complexes were measured and the data were analyzed to determine the role of lipophilicity versus structure in the various biological assays. Cellular uptake increased with lipophilicity but shows the biggest jump when the complex contains two or more dip ligands. Significantly, preferential cytoskeletal localization is also correlated with increased cytotoxicity. All of the RPCs promote tubulin polymerization in vitro, but [Ru(dip)2 phen]2+ and [Ru(dip)3 ]2+ show the strongest activity. Analysis of the pellet formed by centrifugation of MTs formed in the presence of [Ru(dip)2 phen]2+ establish a binding stoichiometry of one RPC per tubulin heterodimer. Complexes of the general formula [Ru(dip)2 (L-L)]2+ possess the necessary characteristics to target the cytoskeleton in live cells and increase cytotoxicity, however the nature of the L-L ligand does influence the extent of the effect.

Fabrication and Evaluation of Anticancer Potential of Eugenol Incorporated Chitosan-Silver Nanocomposites: In Vitro, In Vivo, and In Silico Studies

The expanding global cancer burden necessitates a comprehensive strategy to promote possible therapeutic interventions. Nanomedicine is a cutting-edge approach for treating cancer with minimal adverse effects. In the present study, chitosan-silver nanoparticles (ChAgNPs) containing Eugenol (EGN) were synthesized and evaluated for their anticancer activity against breast cancer cells (MCF-7). The physical, pharmacological, and molecular docking studies were used to characterize these nanoparticles. EGN had been effectively entrapped into hybrid NPs (84 ± 7%). The EGN-ChAgNPs had a diameter of 128 ± 14 nm, a PDI of 0.472 ± 0.118, and a zeta potential of 30.58 ± 6.92 mV. Anticancer activity was measured in vitro using an SRB assay, and the findings revealed that EGN-ChAgNPs demonstrated stronger anticancer activity against MCF-7 cells (IC50 = 14.87 ± 5.34 µg/ml) than pure EGN (30.72 ± 4.91 µg/ml). To support initial cytotoxicity findings, advanced procedures such as cell cycle analysis and genotoxicity were performed. Tumor weight reduction and survival rate were determined using different groups of mice. Both survival rates and tumor weight reduction were higher in the EGN-ChAgNPs (12.5 mg/kg) treated group than in the pure EGN treated group. Based on protein-ligand interactions, it might be proposed that eugenol had a favorable interaction with Aurora Kinase A. It was observed that C9 had the highest HYDE score of any sample, measuring at -6.8 kJ/mol. These results, in conjunction with physical and pharmacological evaluations, implies that EGN-ChAgNPs may be a suitable drug delivery method for treating breast cancer in a safe and efficient way.

New ruthenium(II) complexes with cyclic thio- and semicarbazone: evaluation of cytotoxicity and effects on cell migration and apoptosis of lung cancer cells

We describe the synthesis, physicochemical characterization, and in vitro antitumor assays of four novel analogous ruthenium(II) complexes with general formula cis-[Ru^II(N-L)(P-P)₂]PF₆, where P-P = bis(diphenylphosphine)methane (dppm, in complexes 1 and 2) or bis(diphenylphosphine)ethane (dppe, in complexes 3 and 4) and N-L = 5,6-diphenyl-4,5-dihydro-2H-[1,2,4]triazine-3-thione (Btsc, in complexes 1 and 3) or 5,6-diphenyltriazine-3-one (Bsc, in complexes 2 and 4). The data were consistent with cis arrangement of the biphosphine ligands. For the Btsc and Bsc ligands, the data pointed to monoanionic bidentate coordination to ruthenium(II) through N,S and N,O, respectively. Single-crystal X-ray diffraction showed that complex 1 crystallized in the monoclinic system, space group P2₁/c. Determination of the cytotoxicity profiles of complexes 1-4 gave SI values ranging from 1.19 to 3.50 against the human lung adenocarcinoma cell line A549 and the non-tumor lung cell line MRC-5. Although the molecular docking studies suggested that the interaction between DNA and complex 4 was energetically favorable, the experimental results showed that they interacted weakly. Overall, our results demonstrated that these novel ruthenium(II) complexes have interesting in vitro antitumor potential and this study may contribute to further studies in medicinal inorganic chemistry.

Novel Ru(II)-bipyridine/phenanthroline-lapachol complexes as potential anti-cancer agents

For the first time, we herein report on the syntheses of two new Ru(II)/bipyridine/phenanthroline complexes containing lapachol as ligand: complex (1), [Ru (bipy)₂(Lap)]PF₆ and complex (2), [Ru(Lap)(phen)₂]PF₆, where bipy = 2,2'-bipyridine and ph en = 1,10-phenanthroline; Lap = lapachol (2-hydroxy-3-(3-methylbut-2-en-1- yl)naphthalene-1,4-dione). The complexes were synthesized and characterized by elemental analyses, molar conductivity, mass spectrometry, ultraviolet-visible and infrared spectroscopies, nuclear magnetic resonance (¹H, ¹³C), and single crystal X-ray diffraction, for complex (2). In addition, in vitro cytotoxicity was tested against six cancer cells: A549 (lung carcinoma); DU-145 (human prostate carcinoma); HepG2 (human hepatocellular carcinoma), PC-3 (human prostate adenocarcinoma); MDA-MB-231 (human breast adenocarcinoma); Caco-2 (human colorectal adenocarcinoma), and against two non-cancer cells, FGH (human gingival normal fibroblasts) and PNT-2 (prostate epithelial cells). Complex (1) was slightly more toxic and selective than complex (2) for all cell lines, except against the A549 cells, where (2) was more potent than complex (1). The complexes induced an increase in the reactive oxygen species, and the co-treatment with N-acetyl-L-cysteine remarkably suppressed the ROS generation and prevented the reduction of cell viability, suggesting that the cytotoxicity of the complexes is related to the ROS-mediated pathway. Further studies indicated that the complexes may bind to DNA via minor groove interaction. Our studies also revealed that free Lap induces gene mutations in Salmonella Typhimurium, nevertheless, the complexes demonstrated the absence of genotoxicity by the Ames test. The present study provides a relevant contribution to understanding the anti-cancer potential and genetic toxicological events of new ruthenium complexes containing the lapachol molecule as a ligand.

Preparation, Characterization, and Pharmacological Investigation of Withaferin-A Loaded Nanosponges for Cancer Therapy; In Vitro, In Vivo and Molecular Docking Studies

The rapidly growing global burden of cancer poses a major challenge to public health and demands a robust approach to access promising anticancer therapeutics. In parallel, nanotechnology approaches with various pharmacological properties offer efficacious clinical outcomes. The use of new artificial variants of nanosponges (NS) as a transporter of chemotherapeutic drugs to target cells has emerged as a very promising tool. Therefore, in this research, ethylcellulose (EC) NS were prepared using the ultrasonication assisted-emulsion solvent evaporation technique. Withaferin-A (WFA), an active ingredient in Withania somnifera, has been implanted into the nanospongic framework with enhanced anticancer properties. Inside the polymeric structure, WFA was efficiently entrapped (85 ± 11%). The drug (WFA) was found to be stable within polymeric nanosponges, as demonstrated by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) studies. The WFA-NS had a diameter of 117 ± 4 nm and zeta potential of −39.02 ± 5.71 mV with a polydispersity index (PDI) of 0.419 ± 0.073. In addition, scanning electron microscopy (SEM) revealed the porous surface texture of WFA-NS. In vitro anticancer activity (SRB assay) results showed that WFA–NS exhibited almost twice the anticancer efficacy against MCF-7 cells (IC₅₀ = 1.57 ± 0.091 µM), as quantified by flow cytometry and comet tests. Moreover, fluorescence microscopy with DAPI staining and analysis of DNA fragmentation revealed apoptosis as a mechanism of cancer cell death. The anticancer activity of WFA-NS was further determined in vivo and results were compared to cisplatin. The anticancer activity of WFA-NS was further investigated in vivo, and the data were consistent to those obtained with cisplatin. At Day 10, WFA-NS (10 mg/kg) significantly reduced tumour volume to 72 ± 6%, which was comparable to cisplatin (10 mg/kg), which reduced tumour volume to 78 ± 8%. Finally, the outcomes of molecular modeling (in silico) also suggested that WFA established a stable connection with nanosponges, generating persistent hydrophobic contacts (polar and nonpolar) and helping with the attractive delayed-release features of the formulation. Collectively, all the findings support the use of WFA in nanosponges as a prototype for cancer treatment, and opened up new avenues for increasing the efficacy of natural product-derived medications.

An organometallic catalase mimic with exceptional activity, H2O2 stability, and catalase/peroxidase selectivity

Manganese-porphyrin and -salen redox therapeutics catalyze redox reactions involving O2˙-, H2O2, and other reactive oxygen species, thereby modulating cellular redox states. Many of these complexes perform catalase reactions via high-valent Mn-oxo or -hydroxo intermediates that oxidize H2O2 to O2, but these intermediates can also oxidize other molecules (e.g., thiols), which is peroxidase reactivity. Whether catalase or peroxidase reactivity predominates depends on the metal-ligand set and the local environment, complicating predictions of what therapeutic effects (e.g., promoting vs. suppressing apoptosis) a complex might produce in a given disease. We recently reported an organoruthenium complex (Ru1) that catalyzes ABTS˙- reduction to ABTS2- with H2O2 as the terminal reductant. Given that H2O2 is thermodynamically a stronger oxidant than ABTS˙-, we reasoned that the intermediate that reduced ABTS˙- would also be able to reduce H2O2 to H2O. Herein we demonstrate Ru1-catalyzed H2O2 disproportionation into O2 and H2O, exhibiting an 8,580-fold faster catalase TOF vs. peroxidase TOF, which is 89.2-fold greater than the highest value reported for a Mn-porphyin or -salen complex. Furthermore, Ru1 was 120-fold more stable to H2O2 than the best MnSOD mimic (TON = 4000 vs. 33.4) Mechanistic studies provide evidence that the mechanism for Ru1-catalyzed H2O2 disproportionation is conserved with the mechanism for ABTS˙- reduction. Therapeutic effects of redox catalysts can be predicted with greater accuracy for catalysts that exhibit exclusively catalase activity, thereby facilitating the development of future redox therapeutic strategies for diseases.

New Hybrid Scaffolds Based on Carbazole-Chalcones as Potent Anticancer Agents

BACKGROUND AND OBJECTIVES

Despite various technological advances for the treatment of cancer, the identification of new chemical entities with potent anticancer effects remain an indispensable requirement of the time due to multi-drug resistance exhibited by previously developed anticancer drugs. Particularly, the hybrid drugs incorporating two individual bioactive pharmacophores present medicinally important structural leads, thus improving the pharmacodynamic profile of the drug molecules. The antiproliferative and pro-apoptotic activity of the carbazole-chalcone hybrids on human breast and cervical cancer cells will be examined.

MATERIALS AND METHODS

To overcome such complications, in the current study, we evaluated the cytotoxic effects of carbazole-chalcone hybrids on human breast adenocarcinoma (MCF-7), cervical adenocarcinoma (HeLa) cells and normal cells, i.e., Baby Hamster Kidney cells (BHK-21) using MTT (dimethyl-2-thiazolyl-2,5- diphenyl-2H-tetrazolium bromide) assay. The mechanistic studies were performed on potent compound 4g by fluorescent microscopic studies, release of Lactate Dehydrogenase (LDH) and mitochondrial membrane potential, activation of caspase-9 and -3 and flow cytometric analysis.

RESULTS

As revealed by MTT assay, compound 4g was identified as the most potent derivative among the tested series with IC₅₀ values of 5.64 and 29.15μM against HeLa and MCF-7 cells, respectively. The results were compared with cisplatin. Fluorescent microscopic studies using 4',6-diamidino-2-phenylindole (DAPI) and Propidium Iodide (PI) staining confirmed the occurrence of apoptosis in HeLa cells treated with the most active compound 4g. Moreover, compound 4g also triggered the release of Lactate Dehydrogenase (LDH) in treated HeLa and MCF-7 cells while a fluorescence assay displayed a remarkable increase in the activity of caspase-9 and -3. Moreover, flow cytometric results revealed that compound 4g caused G₀/G₁ arrest in the treated HeLa cells.

CONCLUSION

Our results demonstrated that the compound 4g possesses chemotherapeutic properties against breast cancer and cervical adenocarcinoma cells, thus warranting further research to test the anticancer potential of this compound at preclinical and clinical level.

In Vitro Anticancer Effects of Stilbene Derivatives: Mechanistic Studies on HeLa and MCF-7 Cells

BACKGROUND AND OBJECTIVE

The growing prevalence of cancer and the resulting chemoresistance exert a huge burden on healthcare systems and impose a great challenge to public health around the world. In efforts to develop new chemotherapeutic agents for cancer treatment, a class of heterocyclic compounds i.e. triazine-based molecules were investigated as anticancer agents.

MATERIALS AND METHODS

New triazine hybrids of stilbene were synthesized and evaluated as anticancer agents for cervical (HeLa) and breast (MCF-7) carcinoma cells. The compound (7e), sodium (E)-6,6'-(ethene-1,2- diyl)bis(3-((4-chloro-6-((3-luorophenyl)amino)-1,3,5-triazin-2-yl)amino)benzenesulfonate) was found to be most potent among synthesized derivatives and was explored further for detailed mechanistic studies.

RESULTS

In a set comprised of twelve derivatives, compound 7e, sodium (E)-6,6'-(ethene-1,2-diyl)bis(3-((4- chloro-6-((3-luorophenyl)amino)-1,3,5-triazin-2-yl)amino)benzenesulfonate) was found most potent inhibitor for HeLa and MCF-7 cells.

DISCUSSION

The present study has revealed that compound 7e may activate mitochondrial pathway of apoptosis in HeLa and MCF-7 cells which was assessed by DNA binding studies, estimation of the release of Lactate Dehydrogenase (LDH), fluorescence imaging, production of Reactive Oxygen Species (ROS) in cancer cells, analysis of cell cycle by flow cytometry, change in Mitochondrial Membrane Potential (MMP) and activation of caspase-9 and caspase-3.

CONCLUSION

Compound 7e may serve as a lead in designing new anticancer compounds based on stilbene scaffold.

A Click Chemistry Approach to Developing Molecularly Targeted DNA Scissors

Nucleic acid click chemistry was used to prepare a family of chemically modified triplex forming oligonucleotides (TFOs) for application as a new gene-targeted technology. Azide-bearing phenanthrene ligands-designed to promote triplex stability and copper binding-were 'clicked' to alkyne-modified parallel TFOs. Using this approach, a library of TFO hybrids was prepared and shown to effectively target purine-rich genetic elements in vitro. Several of the hybrids provide significant stabilisation toward melting in parallel triplexes (>20 °C) and DNA damage can be triggered upon copper binding in the presence of added reductant. Therefore, the TFO and 'clicked' ligands work synergistically to provide sequence-selectivity to the copper cutting unit which, in turn, confers high stabilisation to the DNA triplex. To extend the boundaries of this hybrid system further, a click chemistry-based di-copper binding ligand was developed to accommodate designer ancillary ligands such as DPQ and DPPZ. When this ligand was inserted into a TFO, a dramatic improvement in targeted oxidative cleavage is afforded.

Photochemical and Photobiological Properties of Pyridyl-pyrazol(in)e-Based Ruthenium(II) Complexes with Sub-micromolar Cytotoxicity for Phototherapy

The discovery of new light-triggered prodrugs based on ruthenium (II) complexes is a promising approach for photoactivated chemotherapy (PACT). The light-mediated activation of "strained" Ru(II) polypyridyl complexes resulted in ligand release and produced a ligand-deficient metal center capable of forming covalent adducts with biomolecules such as DNA. Based on the strategy of exploiting structural distortion to activate photochemistry, biologically active small molecules were coordinated to a Ru(II) scaffold to create light-triggered dual-action agents. Thirteen new Ru(II) complexes with pyridyl-pyrazol(in)e ligands were synthesized, and their photochemical reactivity and anticancer properties were investigated. Isomeric bidentate ligands were investigated, where "regular" ligands (where the coordinated nitrogens in the heterocycles are linked by C-C atoms) were compared to "inverse" isomers (where the coordinated nitrogens in the heterocycles are linked by C-N atoms). Coordination of the regular 3-(pyrid-2-yl)-pyrazol(in)es to a Ru(II) bis-dimethylphenanthroline scaffold yielded photoresponsive compounds with promising photochemical and biological properties, in contrast to the inverse 1-(pyrid-2-yl)-pyrazolines. The introduction of a phenyl ring to the 1N-pyrazoline cycle increased the distortion in complexes and improved ligand release upon light irradiation (470 nm) up to 5-fold in aqueous media. Compounds 1-8, containing pyridyl-pyrazol(in)e ligands, were at least 20-80-fold more potent than the parent pyridyl-pyrazol(in)es, and exhibited biological activity in the dark, with half-maximal inhibitory concentration (IC₅₀) values ranging from 0.2 to 7.6 μM in the HL60 cell line, with complete growth inhibition upon light irradiation. The diversification of coligands and introduction of a carboxylic acid into the Ru(II) complex resulted in compounds 9-12, with up to 146-fold improved phototoxicity indices compared with complexes 1-8.

Combination Therapy of Doxorubicin and Quercetin on Multidrug-Resistant Breast Cancer and Their Sequential Delivery by Reduction-Sensitive Hyaluronic Acid-Based Conjugate/d-α-Tocopheryl Poly(ethylene glycol) 1000 Succinate Mixed Micelles

The therapeutic efficacy of chemotherapy in many types of hematological malignancies and solid tumors is dramatically hindered by multidrug resistance (MDR). This work presents a combination strategy of pretreatment of MDA-MB-231/MDR1 cells with quercetin (QU) followed by doxorubicin (DOX) to overcome MDR, which can be delivered by mixed micelles composed of the reduction-sensitive hyaluronic acid-based conjugate and d-α-tocopheryl poly(ethylene glycol) 1000 succinate. The combination strategy can enhance the cytotoxicity of DOX on MDA-MB-231/MDR1 cells by increasing intracellular DOX accumulation and facilitating DOX-induced apoptosis. The probable MDR reversal mechanisms are that the pretreatment cells with QU-loaded mixed micelles downregulate P-glycoprotein expression to decrease DOX efflux as well as initiate mitochondria-dependent apoptotic pathways to accelerate DOX-induced apoptosis. In addition, this combination strategy can not only potentiate in vivo tumor-targeting efficiency but also enhance the antitumor effect in MDA-MB-231/MDR1-bearing nude mice without toxicity or side effects. This research suggests that the co-administration of natural compounds and chemotherapeutic drugs could be an effective strategy to overcome tumor MDR, which deserves further exploration.

Cytotoxicity, Pro-apoptotic Activity and in silico Studies of Dithiocarbamates and their Structure Based Design and SAR Studies

Background:

Cancer is a far-reaching and lethal but curable disease. Researchers have investigated numerous anticancer agents with only a few commercially available effective drugs which are very costly.

Objective:

Herein, we report the synthesis , characterization and anti cancer assays of a series of novel dithiocarbamates derivatives.

Methods:

All compounds were synthesized from different secondary amines and substituted benzyl chlorides in a single step. The structures of newly synthesized dithiocarbamate derivatives were confirmed by spectroscopic techniques (IR, NMR and HR-MS).

Results:

The synthesized compounds showed a significant anti-proliferative effect in cancer cells (HeLa) with the maximum inhibitory activity of compound SHD-2 with an IC50 = 0.31 ± 0.09 μM. However, the same compound exhibited 19.2% inhibition towards Baby Hamster Kidney fibroblasts (BHK-21), normal cell lines. Moreover, quantification of cellular DNA by flow cytometry for the evaluation of pro-apoptotic activity in HeLa cells demonstrates that arrest in cell cycle along with apoptosis advance towards drug cytotoxicity. However, molecular docking studies of the potent compound suggested that it binds to the major groove of the DNA.

Conclusion:

The cytotoxic and pro-apoptotic potential of the potent inhibitor may be further investigated in the animal models to advance their anti-cancer prospective.

Eco-friendly green synthesis of silver nanoparticles and their potential applications as antioxidant and anticancer agents

Eco-friendly green synthesis of nanoparticles using medicinal plants gained immense importance due to its potential therapeutic uses. In the current study, silver nanoparticles (AgNPs) were synthesized using water extract of Jurinea dolomiaea leaf and root at room temperature. MTT assay was used to study anticancer potential of AgNPs against cervical cancer cell line (HeLa), breast cancer cell lines (MCF-7), and mouse embryonic fibroblast (NIH-3 T3) cell line for toxicity evaluation. The antioxidant potential was evaluated using stable DPPH radicals. In addition, the apoptotic nuclear changes prompted by AgNPs in more susceptible HeLa cells were observed using fluorescence microscope through DAPI and PI staining. Physiochemical properties of biosynthesized AgNPs were characterized using various techniques. AgNPs were formed in very short time and UV-vis spectra showed characteristic absorption peak of AgNPs. SEM and TEM showed spherical shape of AgNPs and XRD revealed their crystalline nature. EDX analysis revealed high percentage of silver in green synthesized AgNPs. FTIR analysis indicated involvement of secondary metabolites in fabrication of AgNPs. In vitro cytotoxic and antioxidant study revealed that herb and biosynthesized AgNPs exhibited significant dose-dependent and time-dependent anticancer and antioxidant potential. Furthermore, study on normal cell line and microscopic analysis of apoptosis revealed that AgNPs exhibited good safety profile as compared to cisplatin and induces significant apoptosis effect. Based on the current findings, it is strongly believe that use of J. dolomiaea offers large scale production of biocompatible AgNPs that can be used as alternative anticancer agents against cancer cell lines tested.

Synthesis, characterization, and anticancer activity of Schiff bases

Five Schiff bases, 2-((3-chlorophenylimino)methyl)-5-(diethylamino)phenol (L1), 2-((2,4-dichlorophenylimino)methyl)-5-(diethylamino)phenol (L2), 5-(diethylamino)-2-((3,5-dimethylphenylimino)methyl)phenol (L3), 2-((2-chloro-4-methylphenylimino)methyl)-5-(diethylamino)phenol (L4), and 5-(diethylamino)-2-((2,6-diethylphenylimino)methyl)phenol (L5) were synthesized and characterized by elemental analysis, FT-IR, ¹H and ¹³C NMR spectroscopy. Three of the compounds (L1, L2, and L4) were analyzed by single crystal X-ray diffraction: L1 and L2 crystallized in orthorhombic P2₁2₁2₁ and Pca2₁ space group, respectively, while L4 crystallized in monoclinic P2₁/c space group. Theoretical investigations were performed for all the synthesized compounds to evaluate the structural details. Drug-DNA interaction studies results from UV-Vis spectroscopy and electrochemistry complement that the compounds bind to DNA through electrostatic interactions. The cytotoxicity of the synthesized compounds was studied against cancer cell lines (HeLa and MCF-7) and a normal cell line (BHK-21) by means of an MTT assay compared to carboplatin, featuring IC₅₀ values in the micromolar range. The pro-apoptotic mechanism for the active compound L5 was evaluated by fluorescence microscopy, cell cycle analysis, caspase-9 and -3 activity, reactive oxygen species production, and DNA binding studies that further strengthen the results of that L5 is a potent drug against cancer.Communicated by Ramaswamy H. Sarma.

Exploration of quinolone and quinoline derivatives as potential anticancer agents

BACKGROUND

Among the different types of cancers, breast cancer, bone cancer and cervical cancer are the most common gender specific cancer types that are affecting the women worldwide. Currently, many enzymatic and cellular pathways are known as drug targets for the treatment of cancer. Even though many improvements have been made in the therapy of various types of cancer, but the major disadvantage of available anti-cancer drugs is their non-selective behavior towards cancer cells as well as normal cells.

OBJECTIVES

In the light of this fact, the searching of new compounds with selective behavior only towards cancer cells is critically important. Previously, we have identified several series of compounds as the potential inhibitors of these families.

METHODS

Herein, we investigate quinolones and quinolines for their anti-cancer activity against breast cancer cells (MCF-7), bone marrow cancer cells (K-562) and cervical cancer cells (HeLa) by MTT assay. The most effective derivatives were further subjected to flow cytometry analysis followed by fluorescence microscopic analysis by using 4´,6-diamidine-2´-phenylindole (DAPI) and propidium staining (PI) staining.

RESULTS

All the tested compounds were found selective only towards cancer cells. The identified compounds also induced either G2 or S-phase cell cycle arrest within the respective cancer cell line, chromatin condensation and the nuclear fragmentation, as well as maximum interaction with DNA.

CONCLUSIONS

These results provide evidence that the characteristic chemical features of attached groups are the key factors for their anticancer effects and play a useful role in revealing the mechanisms of action in relation to the known compounds in future research programs. Graphical abstract Flow cytometric analysis of cell cycle using propidium iodide staining. Cell apoptosis observed under fluorescence microscope using DAPI and PI staining.

Anti-proliferative Effects of Chromones: Potent Derivatives Affecting Cell Growth and Apoptosis in Breast, Bone-marrow and Cervical Cancer Cells

BACKGROUND

Previously, we have identified 3,3'-carbonyl-bis(chromones) (1a-h, 5e) and 3-(5-(benzylideneamino)thiozol-3-yl)-2H-chromen-2-ones (7a-j) as potent inhibitors of tissue non-specific alkaline phosphatase (TNAP). The present study was designed to investigate the cytotoxic and pro-apoptotic effect of the said derivatives.

METHODS

The anti-proliferative effect of the derivatives was investigated in three cancer cell lines i.e., MCF-7, K-562, HeLa and normal BHK21 cells using MTT assay. The pro-apoptotic effect of the most potent derivatives was investigated by using flow cytometry, DAPI and PI staining and DNA binding studies.

RESULTS

Among all the screened compounds, 1f, 1d, 1c (from 3,3'-carbonyl-bis(chromones), 7c, 7h and 7i (from 3-(5-(benzylideneamino)thiozol-3-yl)-2H-chromen-2-ones) exhibited remarkable growth inhibitory effects. Compounds 1f and 7c were found to be the most potent cytotoxic derivatives against MCF-7; 1d and 7h inhibited most of the proliferation of K-562 cells, whereas 1c and 7i showed maximum growth inhibition in HeLa cells. The identified compounds exerted lower micromolar potency against the respective cell line with significant selectivity over the normal cells (BHK-21). The identified compounds also induced either G2 or S-phase arrest within the respective cancer cells, chromatin condensation and nuclear fragmentation, as well as maximum interaction with DNA.

CONCLUSIONS

These results provide evidence that the characteristic chemical features of attached groups are the key factors for their anticancer effects and play a useful role in revealing the mechanisms of action in relation to the known compounds in future research programs.

Anticancer and antibacterial activity in vitro evaluation of iridium(III) polypyridyl complexes

Three iridium(III) polypyridyl complexes [Ir(ppy)₂(PYTA)](PF₆) (1) (ppy = 2-phenylpyridine), [Ir(bzq)₂(PYTA)](PF₆) (2) (bzq = benzo[h]quinolone) and [Ir(piq)₂(PYTA)](PF₆) (3) (piq = 1-phenylisoquinoline, PYTA = 2,4-diamino-6-(2'-pyridyl)-1,3,5-triazine) were synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR. The cytotoxic activity of the complexes toward cancer SGC-7901, Eca-109, A549, HeLa, HepG2, BEL-7402 and normal LO2 cell lines was investigated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Complex 3 shows the most effective on inhibiting the above cell growth among these complexes. The complexes locate at the lysosomes and mitochondria. AO/EB, Annex V and PI and comet assays indicate that the complexes can induce apoptosis in SGC-7901 cells. Intracellular ROS and mitochondrial membrane potential were examined under fluorescence microscopy. The results demonstrate that the complexes increase the intracellular ROS levels and induce a decrease in the mitochondrial membrane potential. The complexes can enhance intracellular Ca²⁺ concentration and cause a release of cytochrome c. The autophagy was studied using MDC staining and western blot. Complexes 1-3 can effectively inhibit the cell invasion with a concentration-dependent manner. Additionally, the complexes target tubules and inhibit the polymerization of tubules. The antimicrobial activity of the complexes against S. aureus, E. coli, Salmonella and L. monocytogenes was explored. The mechanism shows that the complexes induce apoptosis in SGC-7901 cells through ROS-mediated lysosomal-mitochondrial, targeting tubules and damage DNA pathways. Three iridium(III) complexes [Ir(N-C)₂(PYTA)](PF₆) (N-C = ppy, 1; bzq, 2; piq, 3) were synthesized and characterized. The anticancer activity of the complexes against SGC-7901 cells was studied by apoptosis, comet assay, autophagy, ROS, mitochondrial membrane potential, intracellular Ca²⁺ levels, release of cytochrome c, tubules and western blot analysis. The antibacterial activity in vitro was also assayed.

Development of a novel morphological paclitaxel-loaded PLGA microspheres for effective cancer therapy: in vitro and in vivo evaluations

Sustained release of therapeutic agents into tumor cells is a potential approach to improve therapeutic efficacy, decrease side effects, and the drug administration frequency. Herein, we used the modified double-emulsion solvent evaporation (DSE) method to prepare a novel morphological paclitaxel (PTX) loaded poly(lactide-co-glycolide) (PLGA) microspheres (MS). The prepared rough PTX-PLGA-MS possessed microporous surface and highly porous internal structures, which significantly influenced the drug entrapment and release behaviors. The rough MS with an average particle size of 53.47 ± 2.87 μm achieved high drug loading (15.63%) and encapsulation efficiency (92.82%), and provided a favorable sustained drug release. The in vitro antitumor tests of flow cytometry and fluoroimmunoassay revealed that the rough PTX-PLGA-MS displayed effective anti-gliomas activity and enhanced the cellular PTX uptake through adsorptive endocytosis. Both in vitro and in vivo antitumor results demonstrated that the sustained-release PTX could induce the microtubules assembly and the over-expression of Bax and Cyclin B1 proteins, resulting in the microtubule dynamics disruption, G2/M phase arrest, and cell apoptosis accordingly. Furthermore, as the rough PTX-PLGA-MS could disperse and adhere throughout the tumor sites and cause extensive tumor cell apoptosis with one therapeutic course (12 days), they could reduce the system toxicity and drug administration frequency, thus achieving significant tumor inhibitory effects with rapid sustained drug release. In conclusion, our results verified that the rough PTX-PLGA-MS drug release system could serve as a promising treatment to malignant glioma.

Distinctive inhibition of alkaline phosphatase isozymes by thiazol-2-ylidene-benzamide derivatives: Functional insights into their anticancer role

In the recent years, the role of alkaline phosphatase (AP) isozymes in the cause of neoplastic diseases such as breast, liver, renal, and bone cancer has been confirmed and, thus they represent a novel target for the discovery of anticancer drugs. In this study different derivatives of thiazol-2-ylidene-benzamide were evaluated for their potential to inhibit alkaline phosphatase (AP) isozymes. Their anticancer potential was assessed using human breast cancer (MCF-7), bone-marrow cancer (K-562), and cervical cancer (HeLa) cell lines in comparison to normal cells from baby hamster kidney BHK-21. The results suggested that in comparison to other derivatives, compounds 2i, 2e, and 2a showed more sensitivity towards human tissue non-specific alkaline phosphatase (h-TNAP). Among these, 2″-chloro-N-(3-(4'-fluorophenyl)-4-methylthiazol-2(3H)-ylidene) benzamide (2e) was found as the most potent and selective inhibitor for h-TNAP with an IC₅₀ value of 0.079 ± 0.002 μM. Moreover, a significant correlation was observed between the enzyme inhibition profile and cytotoxic data. The compounds exhibiting maximum anticancer potential also induced maximum apoptosis in the respective cell lines. Furthermore, the DNA interaction studies exhibited the non-covalent mode of interaction with the herring sperm-DNA. Molecular docking studies also supported the in vitro inhibitory activity of potent compounds. Our findings suggested that potent and selective inhibitors might be useful candidates for the treatment or prevention of those diseases associated with the higher level of AP. Moreover, the study can be useful for the researcher to explore more molecular mechanisms of such derivatives and their analogues with the exact findings.

The development of ruthenium(ii) polypyridyl complexes and conjugates for in vitro cellular and in vivo applications

Ruthenium(ii) [Ru(ii)] polypyridyl complexes have been the focus of intense investigations since work began exploring their supramolecular interactions with DNA. In recent years, there have been considerable efforts to translate this solution-based research into a biological environment with the intention of developing new classes of probes, luminescent imaging agents, therapeutics and theranostics. In only 10 years the field has expanded with diverse applications for these complexes as imaging agents and promising candidates for therapeutics. In light of these efforts this review exclusively focuses on the developments of these complexes in biological systems, both in cells and in vivo, and hopes to communicate to readers the diversity of applications within which these complexes have found use, as well as new insights gained along the way and challenges that researchers in this field still face.

4-Aminopyridine based amide derivatives as dual inhibitors of tissue non-specific alkaline phosphatase and ecto-5'-nucleotidase with potential anticancer activity

Ecto-nucleotidase members i.e., ecto-5'-nucleotidase and alkaline phosphatase, hydrolyze extracellular nucleotides and play an important role in purinergic signaling. Their overexpression are implicated in a variety of pathological states, including immunological diseases, bone mineralization, vascular calcification and cancer, and thus they represent an emerging drug targets. In order to design potent and selective inhibitors, new derivatives of 4-aminopyridine have been synthesized (10a-10m) and their structures were established on the basis of spectral data. The effect of nature and position of substituent was interestingly observed and justified on the basis of their detailed structure activity relationships (SARs) against both families of ecto-nucleotidase. Compound 10a displayed significant inhibition (IC₅₀ ± SEM = 0.25 ± 0.05 µM) that was found ≈168 fold more potent as compared to previously reported inhibitor suramin (IC₅₀ ± SEM = 42.1 ± 7.8 µM). This compound exhibited 6 times more selectivity towards h-TNAP over h-e5'NT. The anticancer potential and mechanism were also established using cell viability assay, flow cytometric analysis and nuclear staining. Molecular docking studies were also carried out to gain insight into the binding interaction of potent compounds within the respective enzyme pockets and herring-sperm DNA.

Synthesis and evaluation of new salicylaldehyde-2-picolinylhydrazone Schiff base compounds of Ru(II), Rh(III) and Ir(III) as in vitro antitumor, antibacterial and fluorescence imaging agents

Reaction of salicylaldehyde-2-picolinylhydrazone (HL) Schiff base ligand with precursor compounds [{(p-cymene)RuCl2}2] 1, [{(C6H6)RuCl2}2] 2, [{Cp*RhCl2}2] 3 and [{Cp*IrCl2}2] 4 yielded the corresponding neutral mononuclear compounds 5-8, respectively. The in vitro antitumor evaluation of the compounds 1-8 against Dalton's ascites lymphoma (DL) cells by fluorescence-based apoptosis study and by their half-maximal inhibitory concentration (IC50) values revealed the high antitumor activity of compounds 3, 4, 5 and 6. Compounds 1-8 render comparatively lower apoptotic effect than that of cisplatin on model non-tumor cells, i.e., peripheral blood mononuclear cells (PBMC). The antibacterial evaluation of compounds 5-8 by agar well-diffusion method revealed that compound 6 is significantly effective against all the eight bacterial species considered with zone of inhibition up to 35 mm. Fluorescence imaging study of compounds 5-8 with plasmid circular DNA (pcDNA) and HeLa RNA demonstrated their fluorescence imaging property upon binding with nucleic acids. The docking study with some key enzymes associated with the propagation of cancer such as ribonucleotide reductase, thymidylate synthase, thymidylate phosphorylase and topoisomerase II revealed strong interactions between proteins and compounds 5-8. Conformational analysis by density functional theory (DFT) study has corroborated our experimental observation of the N, N binding mode of ligand. Compounds 5-8 exhibited a HOMO (highest occupied molecular orbital)-LUMO (lowest unoccupied molecular orbital) energy gap 2.99-3.04 eV. Half-sandwich ruthenium, rhodium and iridium compounds were obtained by treatment of metal precursors with salicylaldehyde-2-picolinylhydrazone (HL) by in situ metal-mediated deprotonation of the ligand. Compounds under investigation have shown potential antitumor, antibacterial and fluorescence imaging properties. Arene ruthenium compounds exhibited higher activity compared to that of Cp*Rh/Cp*Ir in inhibiting the cancer cells growth and pathogenic bacteria. At a concentration 100 µg/mL, the apoptosis activity of arene ruthenium compounds, 5 and 6 (~30 %) is double to that of Cp*Rh/Cp*Ir compounds, 7 and 8 (~12 %). Among the four new compounds 5-8, the benzene ruthenium compound, i.e., compound 6 is significantly effective against the pathogenic bacteria under investigation.

DNA interaction, antioxidant activity, and bioactivity studies of two ruthenium(II) complexes

Two new ruthenium(II) polypyridyl complexes [Ru(dmb)2(dcdppz)](ClO4)2 (1) and [Ru(bpy)2(dcdppz)](ClO4)2 (2) were prepared and characterized. The crystal structure of the complex 2 was solved by single crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group P21/n with a=12.9622(14)Å, b=17.1619(19)Å, c=22.7210(3)Å, β=100.930(2)(°), R=0.0536, Rω=0.1111. The DNA-binding constants for complexes 1 and 2 were determined to be 1.92×10(5) (s=1.72) and 2.24×10(5) (s=1.86)M(-1), respectively. The DNA-binding behaviors showed that complexes 1 and 2 interact with DNA by intercalative mode. The antioxidant activities of the ligand and the complexes were performed. Ligand, dcdppz, has no cytotoxicity against the selected cell lines. Complex 1 shows higher cytotoxicity than complex 2, but lower than cisplatin toward selected cell lines. The apoptosis and cell cycle arrest were investigated, and the apoptotic mechanism of BEL-7402 cells was studied by reactive oxygen species (ROS), mitochondrial membrane potential and western blot analysis. Complex 1 induces apoptosis in BEL-7402 cells through ROS-mediated mitochondrial dysfunction pathway and by regulating the expression of Bcl-2 family proteins.

Synthesis, characterization, crystal structure, cytotoxicity, apoptosis and cell cycle arrest of ruthenium(ii) complex [Ru(bpy)2(adpa)](PF6)2 (bpy = 2,2′-bipyridine, adpa = 4-(4-aminophenyl)diazenyl-N-(pyridin-2-ylmethylene)aniline)

A new ruthenium complex (Ru-adpa) characterized by single X-ray diffraction exhibits excellent cytotoxicity against AGS cells.

Cytotoxicity in vitro, cell migration and apoptotic mechanism studies induced by ruthenium(ii) complexes

Four Ru(ii) complexes [Ru(N–N)₂(DHBT)](ClO₄)₂ were synthesized and characterized. The cytotoxicity in vitro, apoptosis, comet assay, cell migration, ROS, mitochondrial membrane potential, cell cycle arrest and expression of proteins were investigated.