Anticancer and antimicrobial activity of new copper (II) complexes

Unveiling the promising anticancer effect of copper-based compounds: a comprehensive review

Copper is a necessary micronutrient for maintaining the well-being of the human body. The biological activity of organic ligands, especially their anticancer activity, is often enhanced when they coordinate with copper(I) and (II) ions. Copper and its compounds are capable of inducing tumor cell death through various mechanisms of action, including activation of apoptosis signaling pathways by reactive oxygen species (ROS), inhibition of angiogenesis, induction of cuproptosis, and paraptosis. Some of the copper complexes are currently being evaluated in clinical trials for their ability to map tumor hypoxia in various cancers, including locally advanced rectal cancer and bulky tumors. Several studies have shown that copper nanoparticles can be used as effective agents in chemodynamic therapy, phototherapy, hyperthermia, and immunotherapy. Despite the promising anticancer activity of copper-based compounds, their use in clinical trials is subject to certain limitations. Elevated copper concentrations may promote tumor growth, angiogenesis, and metastasis by affecting cellular processes.

Macrophages morphology and cytokine reeducation by ex situ copper thiol complexes

OBJECTIVE

To study the reeducation effect of copper thiol complexes on macrophage morphology and cytokine expression.

METHODS

The effect of copper thiol complexes was assessed on murine macrophages by the cell morphology observed through optical microscopy, while the expression of cytokines by protein abundance after stimulation. A viability experiment was performed on PMBC to confirm that copper complexes do not affect other cells.

RESULTS

The M1 shape was reported after treatment with copper thiol complexes at 1-200 µM, while M2 behavior was documented between 50 and 800 µM. Surprisingly, a thin elongate morphology was observed between 400-800 µM like the M2 shape. The expression of M1 cytokines was noted ranging from 1 to 100 µM, with the highest yield at 1 µM (2243 pg/µL) for the copper-penicillamine complex. M2 production behavior was observed at 1-800 µM, with the highest abundance close to 1150 pg/µL (200-400 µM) was quantified from the copper-cysteine complex. Finally, LCCu complexes did not induce a cytotoxic response on PBMC while exhibiting a high IL-4 and IL-10 production, similar to their gold analogs.

CONCLUSIONS

The capacity of copper thiol complexes to reeducate M1 to M2 morphoexpression can be promising for cell protection by using copper thiol penicillamine or immuno-regeneration of tissues when using copper thiol cysteine.

Bimetallic bis-Aroyldihydrazone-Isatin Complexes of High O=V(IV) and Low Cu(II) Valent Ions as Effective Biological Reagents for Antimicrobial and Anticancer Assays

Due to the versatile bioreactivity of aroyldihydrazone complexes as cost-effective alternatives with different transition metals, two novel bimetallic homo-complexes (VOLph and CuLph) were prepared via the coordination of a terephthalic dihydrazone diisatin ligand (H2Lph) with VO2+ and Cu2+ ions, respectively. The structure elucidation was confirmed by alternative spectral methods. Biologically, the H2Lph ligand and its MLph complexes (M2+ = VO2+ or Cu2+) were investigated as antimicrobial and anticancer agents. Their biochemical activities towards ctDNA (calf thymus DNA) were estimated using measurable titration viscometrically and spectrophotometrically, as well as the gel electrophoresis technique. The growth inhibition of both VOLph and CuLph complexes against microbial and cancer cells was measured, and the inhibition action, MIC, and IC50 were compared to the inhibition action of the free H2Lph ligand. Both VOLph and CuLph showed remarkable interactive binding with ctDNA compared to the free ligand H2Lph, based on Kb = 16.31, 16.04 and 12.41 × 107 mol-1 dm3 and ΔGb≠ = 47.11, -46.89, and -44.05 kJ mol-1 for VOLph, CuLph, and H2Lph, respectively, due to the central metal ion (VIVO and CuII ions). VOLph (with a higher oxidation state of the V4+ ion and oxo-ligand) exhibited enhanced interaction with the ctDNA molecule compared to CuLph, demonstrating the role and type of the central metal ion within the performed electronegative and electrophilic characters.

Copper(II) Complexes with 1-(Isoquinolin-3-yl)heteroalkyl-2-ones: Synthesis, Structure and Evaluation of Anticancer, Antimicrobial and Antioxidant Potential

Four copper(II) complexes, C1-4, derived from 1-(isoquinolin-3-yl)heteroalkyl-2-one ligands L1-4 were synthesized and characterized using an elemental analysis, IR spectroscopic data as well as single crystal X-ray diffraction data for complex C1. The stability of complexes C1-4 under conditions mimicking the physiological environment was estimated using UV-Vis spectrophotometry. The antiproliferative activity of both ligands L1-4 and copper(II) compounds C1-4 were evaluated using an MTT assay on four human cancer cell lines, A375 (melanoma), HepG2 (hepatoma), LS-180 (colon cancer) and T98G (glioblastoma), and a non-cancerous cell line, CCD-1059Sk (human normal skin fibroblasts). Complexes C1-4 showed greater potency against HepG2, LS180 and T98G cancer cell lines than etoposide (IC50 = 5.04-14.89 μg/mL vs. IC50 = 43.21->100 μg/mL), while free ligands L1-4 remained inactive in all cell lines. The prominent copper(II) compound C2 appeared to be more selective towards cancer cells compared with normal cells than compounds C1, C3 and C4. The treatment of HepG2 and T98G cells with complex C2 resulted in sub-G1 and G2/M cell cycle arrest, respectively, which was accompanied by DNA degradation. Moreover, the non-cytotoxic doses of C2 synergistically enhanced the cytotoxic effects of chemotherapeutic drugs, including etoposide, 5-fluorouracil and temozolomide, in HepG2 and T98G cells. The antimicrobial activities of ligands L2-4 and their copper(II) complexes C2-4 were evaluated using different types of Gram-positive bacteria, Gram-negative bacteria and yeast species. No correlation was found between the results of the antiproliferative and antimicrobial experiments. The antioxidant activities of all compounds were determined using the DPPH and ABTS radical scavenging methods. Antiradical tests revealed that among the investigated compounds, copper(II) complex C4 possessed the strongest antioxidant properties. Finally, the ADME technique was used to determine the physicochemical and drug-likeness properties of the obtained complexes.

Carnosine, Zinc and Copper: A Menage a Trois in Bone and Cartilage Protection

Dysregulated metal homeostasis is associated with many pathological conditions, including arthritic diseases. Osteoarthritis and rheumatoid arthritis are the two most prevalent disorders that damage the joints and lead to cartilage and bone destruction. Recent studies show that the levels of zinc (Zn) and copper (Cu) are generally altered in the serum of arthritis patients. Therefore, metal dyshomeostasis may reflect the contribution of these trace elements to the disease's pathogenesis and manifestations, suggesting their potential for prognosis and treatment. Carnosine (Car) also emerged as a biomarker in arthritis and exerts protective and osteogenic effects in arthritic joints. Notably, its zinc(II) complex, polaprezinc, has been recently proposed as a drug-repurposing candidate for bone fracture healing. On these bases, this review article aims to provide an overview of the beneficial roles of Cu and Zn in bone and cartilage health and their potential application in tissue engineering. The effects of Car and polaprezinc in promoting cartilage and bone regeneration are also discussed. We hypothesize that polaprezinc could exchange Zn for Cu, present in the culture media, due to its higher sequestering ability towards Cu. However, future studies should unveil the potential contribution of Cu in the beneficial effects of polaprezinc.

Hydrazylpyridine salicylaldehyde-copper(II)-1,10-phenanthroline complexes as potential anticancer agents: synthesis, characterization and anticancer evaluation

We synthesized and analyzed nine unique copper(II) hydrazylpyridine salicylaldehyde and 1,10-phenanthroline complexes, [Cu(L1a)(phen)] (Cugdupt1), [Cu(L2a)(phen)]·(CH3CN) (Cugdupt2), [Cu(L3a)(phen)] (Cugdupt3), [Cu(L4a)(phen)]·(CH3CN) (Cugdupt4), [Cu(L5a)(phen)] (Cugdupt5), [Cu(L6a)(phen)] (Cugdupt6), [Cu(L7a)(phen)] (Cugdupt7) [Cu(L8a)(phen)] (Cugdupt8) and [Cu(L9a)(phen)]·0.5(H2O) (Cugdupt9). We were motivated by the intriguing properties of the coupled ligands of hydrazylpyridine, salicylaldehyde, and 1,10-phenanthroline. The MTT assay demonstrated that Cugdupt1-Cugdupt9 have higher anticancer activity than L1H2-L9H2, phen and cisplatin on A549/DDP cancer cells (A549cis). Cugdupt1-Cugdupt9 were superior to cisplatin with IC50 values of 1.6-100.0 fold on A549cis cells (IC50(Cugdupt1-Cugdupt9) = 0.5-30.5 μM, IC50(cisplatin) = 61.5 ± 1.0 μM). However, Cugdupt1-Cugdupt9 had lower cytotoxicity toward the HL-7702 normal cells. Cugdupt1 and Cugdupt8 can induce reduction of mitochondrial respiratory chain complexes I/IV (MRCC-I/IV), mitophagy pathways, and eventually protein regulation and adenosine triphosphate (ATP) depletion in A549cis cells. The findings indicated that Cugdupt1 and Cugdupt8 caused cell death via both ATP diminution and mitophagy pathways. Finally, Cugdupt8 demonstrated high efficacy and no obvious cytotoxicity in A549 tumor-bearing mice. This study thus helps evaluate the potential of the hydrazylpyridine salicylaldehyde-copper(II)-1,10-phenanthroline compounds for cisplatin-resistant tumor therapy.

New Copper Complexes with Antibacterial and Cytotoxic Activity

The discovery of a new non-toxic metal complex with biological activity represents a very active area of research. Two Cu+2 complexes, [Cu4(L1)4(OH)4(DMF)2(H2O)] (C1) (HL1 = N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)-benzenesulfonamide) and [Cu(L2)2(phen)(H2O)] (C2) (HL2 = N-(5-(4-methylphenyl)-[1,3,4]-thiadiazole-2-yl)-naphtalenesulfonamide), with two new ligands were synthesized. The X-ray crystal structures of the complexes were determined. In both complexes, Cu+2 is five-coordinated, forming a CuN2O3 and CuN4O chromophore, respectively. The ligands act as monodentate, coordinating the metal ion through a single Nthiadiazole atom; for the two complexes, the molecules from the reaction medium (phenantroline, dimethylformamide and water) are also involved in the coordination of Cu+2. The complexes have a distorted square pyramidal square-planar geometry. The compounds were characterized by FT-IR and UV-Vis spectroscopy. Using the microdilution method, the antibacterial activity of the complexes was determined against four Gram-positive and two Gram-negative bacteria, with Gentamicin as the positive control. Cytotoxicity studies were carried out on two tumor cell lines (HeLa, DLD-1) and on a normal cell line (HFL1) using the MTT method and Cisplatin as a positive control. Flow cytometric assessment of apoptosis induced by the complexes on the three cell lines was also performed. Both complexes present in vitro biological activities but complex C2 is more active.

Anticancer properties of complexes derived from bidentate ligands

Cancer is the abnormal division and multiplication of cells in an organ or tissue. It is the second leading cause of death globally. There are various types of cancer such as prostate, breast, colon, lung, stomach, liver, skin, and many others depending on the tissue or organ where the abnormal growth originates. Despite the huge investment in the development of anticancer agents, the transition of research to medications that improve substantially the treatment of cancer is less than 10%. Cisplatin and its analogs are ubiquitous metal-based anticancer agents notable for the treatment of various cancerous cells and tumors but unfortunately accompanied by large toxicities due to low selectivity between cancerous and normal cells. The improved toxicity profile of cisplatin analogs bearing bidentate ligands has motivated the synthesis of vast metal complexes of bidentate ligands. Complexes derived from bidentate ligands such as β-diketones, diolefins, benzimidazoles and dithiocarbamates have been reported to possess 20 to 15,600-fold better anticancer activity, when tested on cell lines, than some known antitumor drugs currently on the market, e.g. cisplatin, oxaliplatin, carboplatin, doxorubicin, and 5-fluorouracil. This work discusses the anticancer properties of various metal complexes derived from bidentate ligands, for possible application in chemotherapy. The results discussed were evaluated by the IC50 values as obtained from cell line tests on various metal-bidentate complexes. The structure-activity relationship study of the complexes discussed, revealed that hydrophobicity is a key factor that influences anticancer properties of molecules.

Pharmacological activity and mechanism of pyrazines

Heterocycles are common in the structure of drugs used clinically to deal with diseases. Such drugs usually contain nitrogen, oxygen and sulfur, which possess electron-accepting capacity and can form hydrogen bonds. These properties often bring enhanced target binding ability to these compounds when compared to alkanes. Pyrazine is a nitrogen-containing six-membered heterocyclic ring and many of its derivatives are identified as bioactive molecules. We review here the most active pyrazine compounds in terms of their structure, activity in vitro and in vivo (mainly antitumor activity) and the reported mechanisms of action. References have been downloaded through Web of Science, PubMed, Science Direct, Google Scholar and SciFinder Scholar. Publications reporting only the chemistry of pyrazine derivatives are beyond the scope of this review and have not been included. We found that compounds in which a pyrazine ring was fused into other heterocycles especially pyrrole or imidazole were the highly studied pyrazine derivatives, whose antineoplastic activity had been widely investigated. To the best of our knowledge, this is the first review of pyrazine derivatives and their bioactivity, especially their antitumor activity. This review should be useful for those engaged in development of medications based on heterocyclic compounds especially those based on pyrazine.